HRP940121A2 - Electrical smoking apparatus for creating and delivering flavours, and a process for the production thereof - Google Patents

Description

The origin of the invention

This invention relates to a smoking device in which cigarettes are used with lighters, and a process for its production.

In our US patent no. No. 5,060,671 describes an electric smoking device, which is incorporated herein by reference in its entirety. That patent described a smoking device equipped with a set of disposable electric heaters. A filling of a tobacco-flavored agent, for example tobacco or tobacco products, is placed on each heating element. The disposable heater/flavoring unit connects to an electrical power source such as a battery or capacitor, as well as a control circuit to activate the heater that responds to the pull of smoke from the smoker or to the push of a hand switch. The control system is designed so that with each smoke intake, at least one, but less than the total number of heating elements, is switched on, and so that a previously determined number of smokes, each of which contains a previously measured amount of tobacco aroma substance, e.g. an aerosol containing the aroma of tobacco, released by the smoker. The control circuit preferably prevents each individual heater from being turned on more than once to prevent overheating of the tobacco flavoring agent located on the heater. With such articles (devices), the heater is thrown away together with the rest of the spent tobacco material. Also, the electrical connections between the heater and the battery cartridge must be such that they can withstand repeated removal and reconnection when replacing the aroma production parts.

In our still valid US Patent application ser. no. 07/666,926 filed on March 11, 1991, which is now abandoned in favor of permanent application ser. no. 08/012,799, filed on February 2, 1995, disclosed an electric smoking device (article) that has reusable heating elements and a disposable part for producing tobacco flavoring. This disposable portion includes, preferably, an aromatic segment and a filter segment that is attached with a thin filter paper or other means. In any case, with heating elements for multiple use there are certain difficulties in application, especially because the rest of the aerosol shows a tendency to deposit condensate on the heating elements as well as on other permanent components of the device.

The aim of the present invention is to alleviate the above-mentioned problems.

This invention, in its various embodiments (aspects), is defined by the independent patent claims to which reference should be made.

The smoking device according to the present invention, in which cigarettes are used with lighters, has the advantage of enabling improved delivery (creation) of aroma. The advantage of the smoking device made according to this invention is that the heating elements of the lighter can be used multiple times, while the volume of discarded parts is reduced to a minimum.

The device according to the present invention has the advantage that aerosol condensation on the heating elements and other constituent components of the lighter is minimized.

The smoking article made in accordance with the present invention as well as the manufacturing processes for making it and also incorporating the present invention have the advantage of being simple and cost-effective, even at today's mass production speeds.

Embodiments incorporating the present invention have the further advantage of enabling improved production and delivery of aerosol and aroma to the smoker.

In accordance with one recommended embodiment corresponding to one variant (aspect) of this invention, it is provided that a cigarette is used for the production and delivery of tobacco aroma in the smoking apparatus, wherein this system includes heating elements. The cigarette includes a carrier having first and second ends spaced apart in the longitudinal direction, and having first and second surfaces. The first surface defines a cavity between the first and second ends, and the second surface includes a zone that is placed adjacent to the heater elements. The tobacco-flavored material is placed on the first surface of the carrier. The tobacco-flavored material produces tobacco flavor in the cavity for delivery to the smoker when the material is heated by the heating elements. The support and material with tobacco aroma enable the transverse flow of air in the cavity.

In accordance with the recommended embodiment in the second variant of this invention, in the smoking device that gives the smoker the aroma of tobacco, a lighter is used in combination with a cigarette that can be removed, wherein the lighter includes a holder (tension element) into which, through the first end, cigarette. The holder of the heater is designed in such a way that it enables a transverse flow of air to at least one part of the cigarette.

A large number of heating elements are placed in the heater holder.

Each of the heating elements has a surface that is placed immediately next to the surface of that part of the cigarette to which the transverse flow of air is enabled.

A system is provided for activating (switching on) one or several of the total number of electric heaters, so that a predetermined amount of tobacco aroma is produced on the cigarette. Cross-flow of air occurs when a smoker draws in smoke from a cigarette placed in the lighter.

In accordance with the recommended embodiment of the second variant of the subject invention, a smoking device is provided for providing tobacco aroma to the smoker. This device individually includes a number of electrical elements for heating, so that a previously determined amount of tobacco aroma is created in the cavity of the cigarette.

In accordance with the recommended embodiment of another variant of the subject invention, a heater element is provided for use in a smoking device that provides the smoker with a tobacco aroma. The heating element includes a first end and a second end, and a plurality of curved zones between the first and second ends to increase the electrical resistance of the heating element. The heating element is made of a resistant material and has the first and second surfaces mostly oriented (placed) in a plane, and has a total length L, a total width W and a thickness T. The effective length of the heating element in the electrical sense is much greater than the length L, and the effective the electrical cross-sectional area of the heating element is less than the product of W and T.

In accordance with a recommended embodiment of another aspect of the present invention, a process for manufacturing a heater assembly as a whole for use in a smoking apparatus for creating and imparting tobacco flavor to a smoker is described.

In accordance with this procedure, a plate (sheet) made of electrically resistant material is cut to form a large number of heating elements that are connected to each other at least at one end. The plate is cylindrical.

The embodiments of this invention in their various variants will now be described, by means of examples, with reference to the attached drawings, in which:

Figure 1 is a schematic perspective view of a smoking device incorporating the present invention;

Fig. 2 is a schematic partial cross-sectional perspective view of a smoking apparatus according to the present invention;

Figure 3A is a cross-sectional view of a heater assembly incorporating the present invention;

Figure 3B is a side view in section 3B-3B of Figure 3A;

Figure 4A is a schematic perspective view of a cigarette according to the present invention;

Figure 4B is a longitudinal cross-sectional view 4B-4B of Figure 4A;

Figure 5 is a schematic assembly drawing of a heater assembly according to the present invention;

Fig. 6 is a perspective view of a heater constructed according to the present invention;

Figure 7 is a view of a developed heater jacket according to the present invention;

Figure 8 is a perspective view of a portion of a heating element according to the present invention;

Figure 9 is a perspective view of a plug-in element according to the present invention;

Figure 10A is a cross-sectional view of a spacer according to the present invention:

Figure 10B is a schematic side view in plane 10B-10B of Figure 10A;

Figure 10C is a schematic side view in plane 10C-10C of Figure 10A;

Figure 11A is a schematic cross-sectional view of a base according to the present invention;

Figure 11B is a schematic side view in plane 11B-11B of Figure 11A;

Figure 11C is a schematic side view in plane 11C-11C of Figure 11A;

Figure 12A is a schematic perspective view of the combined base and spacer;

Figure 12B is a schematic cross-sectional view in plane 12B-12B of Figure:12A;

Figure 12C is a schematic side view in plane 12C-12C of Figure 12A;

Figure 12D is a schematic side view in plane 12D-12D of Figure 12A;

Figure 13 is a side view of a ring in accordance with one embodiment of the present invention;

Figure 14A is a schematic perspective view of a cap in accordance with one embodiment of the present invention;

Figure 14B is a schematic cross-sectional view in plane 14B-14B of Figure 14A;

Figure 14C is a schematic side view in plane 14C-14C of Figure 14A;

Figure 14D is a schematic side view in plane 14D-14D of Figure 14A;

Figure 15A is a schematic diagram of a heater sleeve in accordance with the present invention;

Figure 15B is a side view in plane 15B-15B from Figure 15A;

Figures 16 and 17 show schematic drawings of the longitudinal section of parts of the smoking apparatus showing the air flow paths in the smoking apparatus;

Fig. 18 is a connection diagram of the control circuit according to the present invention;

Fig. 19 is a schematic drawing in longitudinal section of another smoking apparatus incorporating embodiments in accordance with the present invention;

Figure 20 is a schematic drawing of a longitudinal section of another heater assembly incorporating the present invention;

Fig. 21 is a schematic perspective view of an apparatus for producing the middle portion of a disposable cigarette used in the smoking apparatus of Fig. 19;

Fig. 22 is a schematic drawing of a longitudinal cross-section of a smoking apparatus in an embodiment that allows circumferential retraction and is made in accordance with the present invention;

Figure 23 is a circuit diagram showing another control circuit in accordance with the present invention; and

Figure 24 is a connection diagram of the network for time regulation of the control circuit from Figure 23.

Detailed description

The smoking apparatus 21 according to the present invention is visible in Figures 1 and 2. The smoking apparatus 21 includes a cigarette 23 and a lighter 25 for multiple use. The cigarette 23 is adapted to be inserted and removed from the throat 27 at the front end 29 of the lighter 25. The smoking apparatus 21 is used in almost the same way as conventional cigarettes. The cigarette 23 is discarded after one or more smoke inhalation cycles. The lighter 25 is preferably thrown away after a greater number of smoke inhalation cycles than the cigarette 23.

The lighter 25 includes a housing 31, and has a front and rear part 33 and 35. The energy source 37 that supplies energy to the heating elements for heating the cigarette 23 is located, if possible, in the rear part 35 of the lighter 25. The rear part 35 should be designed so that easily opens and closes, for example with screws or snap fasteners, to allow easy replacement of the power source 37. The front part 33 is provided for housing the heating elements and the control circuit in electrical connection with the power source 37 located in the rear part 35. the part 33 should be able to be easily connected to the rear part 35, for example by hinged connection or by means of a socket. The housing 31 should preferably be made of hard, heat-resistant material. Recommended materials include metal-based materials or, even better, polymer-based materials. The housing 31 should be designed so that it fits and lies well in the hand of the smoker and that, in the version in question, it has overall dimensions of 10.7 cm x 3.8 cm x 1.5 cm.

The energy source 37 is sized to provide enough power for the heating elements that heat the cigarette 23.

The energy source 37 should preferably be replaceable and rechargeable and may consist of a capacitor or a battery pack. In the proposed embodiment, the energy source is a replaceable, rechargeable battery (in fact, four nickel-cadmium battery cartridges connected in series) with a total no-load voltage of 4.8 to 5.6 V. The required characteristics of the energy source 37 are in any case selected in accordance with the characteristics of the other components of the apparatus for smoking 21, especially in accordance with the characteristics of the heating elements. LOUSE. patent no. 5,144,962 describes several forms of power sources that can be used with the smoking apparatus of the present invention, such as rechargeable battery power sources and battery-charged fast-discharge capacitor power sources (accumulator), which is why this patent is here listed as a reference.

A mainly cylindrical heater assembly 39 that heats the cigarette 23 and holds the cigarette in a certain position relative to the lighter 25, as well as an electrical control assembly (circuit) 41 for sending a predetermined amount of energy from the energy source 37 to the heating elements (not visible in Figures 1 and 2) as part of the heater, they are located in the front part of 33 lighters. In the presently proposed embodiment, the heater assembly 39 contains eight radially spaced heating elements 43, shown in Figure 3A, which are individually supplied with energy from the power source 37 via the control assembly 41 to heat eight zones around the periphery of the cigarette 23 and produce eight aroma "smokes" tobacco. Although some other number of heating elements 43 can be installed, eight heating elements are recommended for the reason that even with a conventional cigarette, nominally eight smoke intakes can be achieved, and because eight elements can be electrically controlled by binary devices.

It is recommended that the control circuit 41 be actuated by a smoke-intake responsive sensor 45, shown in Figure 2, which is sensitive to either pressure changes or airflow changes that occur when the smoker inhales the smoke on the cigarette 23. Sensor 45 which reacts to smoke intake is located preferably in the front part 33 of the lighter 25, and is connected to the space inside the heater assembly 39 and in the vicinity of the cigarette 23 via a passage 47 that extends through the spacer element 49 and the base 50 of the heater assembly and, if required, via the sensor tube (not shown). A smoke responsive sensor 45 suitable for use in the smoking apparatus 21 is described in U.S. Pat. Patent no. 5,060,671, from which the invention is incorporated herein by reference, and is made in the form of a silicon sensor Model 163PCO1D35, manufactured by the Microswitch division of Honeywell Inc., Freeport, 111., which includes a corresponding heating element 43 as a result of a change in pressure when the smoker inhales cigarette smoke 23. Flow sensors, such as those using the principles of hot wire flow velocity measurement, have been successfully proven in practice to be useful for activating a corresponding one of all heating elements 43 based on registering a change in air flow.

On the outside of the lighter 25, preferably on the front part 33, an indicator 51 is placed to indicate the number of "smokes" remaining on the cigarette 23 inserted in the lighter. Indicator 51 has a seven-segment screen (display) with a liquid crystal. In the currently proposed embodiment, the indicator 51 shows the number "8" when the light beam emitted by the light sensor 53, visible in Figure 2, is reflected from the front of the inserted new cigarette 23, and is again captured by the light sensor. The light sensor 53 is preferably incorporated into the opening 55 of the spacer 49 and the base 50 of the heater assembly 39, as seen, for example, in Figure 3A. The light sensor 53 gives a signal to the control unit 41, which further sends a signal to the indicator 51. The number "8" on the screen of the indicator 51 shows that there are still eight "smokes" on each cigarette 23, i.e., none of the heating elements 43 were turned on for heating a cigarette.

After cigarette 23 has been smoked to the end, the indicator shows the number "0". When the cigarette 23 is removed from the lighter 25, the light sensor 53 does not register the presence of the cigarette 23 and the indicator 51 turns off. The light sensor 53 is modulated in such a way that it does not emit a light beam continuously, and thus does not unnecessarily consume energy from the energy source 37. The light sensor 53 in question, suitable for use in the smoking device 21, is of the OPR5005 Light Sensor type, manufactured by OPTEK Technology Inc. ., 1215 West Crosby Road, Carrollton, Texas 75006.

As one of the possible alternatives for the application of the above-mentioned light sensor 53, a mechanical switch can be installed to detect the presence or absence of a cigarette 23, as well as a reset button (not shown) for returning the control circuit 41 to the initial state when a new cigarette is inserted into the lighter 25 cigarette, that is, the indicator 51 would show the number "8", etc. Power sources, control circuits, smoke-responsive sensors, and indicators applicable to the smoking apparatus 21 of the present invention are described in U.S. Pat. patent no. 5,060,671 which is incorporated herein by reference. The passage 47 and the opening 55 in the spacer element 49 and the base 50 of the heater assembly should be preferably airtight during smoking.

Here, the preferred cigarette 23 for use in the smoking apparatus 21 is seen in more detail in Figures 4A and 4B, although the cigarette may be in any desired form in which it can impart a tobacco flavor to the smoker when the cigarette is heated by the heating elements 43. The cigarette 23 includes tobacco paper. (weaving) 57 which is made of a supporting part or plenum 59 (a space filled with a substance) which carries a tobacco-flavoured material 61, which preferably includes tobacco. The tobacco paper 57 is wrapped around and stiffened by a cylindrical return filter 63 at one end and a cylindrical free-pass first filter 65 at the opposite end. That first filter with a free passage 65 should, if possible, be an "open pipe" type filter that has a longitudinal passage 67 that passes through the middle of the first filter with a free passage and thus enables a small resistance to smoke entrainment, i.e. free flow.

If desired, cigarette paper 69 may be wrapped around the tobacco layer (paper) 57. Types of paper that can be used as the outer wrapper 69 include light basis weight paper, preferably tobacco flavored paper or tobacco based paper to the tobacco aroma of each flavored "smoke" intensified. Wrapping paper 69 can be coated with liquid extract in concentrated or diluted form. Wrapping paper 69 should preferably have minimal weight and porosity while at the same time having sufficient tensile strength for machining procedures. Here, the preferred characteristics of tobacco-based paper include a basis weight (at 60% relative humidity) between 20-25 g/m2, a minimum permeability of 0-25 CORESTA (defined as the amount of air, measured in cubic centimeters) passing through one square centimeter of the material , for example sheet of paper, in one minute with a pressure drop of 1.0 kPa), tensile strength ≥ 2000 grams/27 mm width (1 in/min - 2.54 cm/min), hole diameter in the paper 1.3-1.5 mils (1mil=0.001 in =0.0254 mm - eg.pr.), CaCO3 content ≤ 5%, citrate 0%. Materials for making the wrapper 69 preferably include 75% tobacco-based paper (non-cigar smoke-cured or mixed smoke/air-cured filler compound and fresh (light) stem). Flax fibers may be added in an amount no greater than necessary to achieve adequate tensile strength. The wrapping paper 69 can also be conventional paper with flax fibers of a basis weight of 15-20 g/m2 or such paper with an extract coating. A binder in the form of lemon pectin may be added in amounts less than or equal to 1%. Glycerin can also be added in an amount that is not greater than necessary to achieve the stiffness of the paper as in a classic cigarette.

Cigarette 23 also has a cylindrical mouthpiece 71 (the tip of the cigarette that is placed in the mouth), preferably a conventional filter of the RDT (Resistance to draw) type, and a cylindrical second free-flow filter 73. Filter (mouthpiece) 71 and a second free-flow filter flow lines 73 are bound together by a thin filter paper 75. This filter paper 75 passes over one end of the second free-pass filter 73 and is connected to the wrapping paper 69 to secure one end of the first free-pass filter 65 in position all the way to the end of the second free-pass filter passing through. Like the first free-pass filter 65, the second free-pass filter 73 is made with a longitudinal passage 77 extending through its middle. The return filter 63 and the first free-pass filter 65 form, together with the tobacco paper 57, a cavity 79 inside the cigarette 23. It is recommended that the inner diameter of the longitudinal passage 77 of the second free-pass filter 73 be greater than the inner diameter of the longitudinal passage 67 of the first free-pass filter through the passage 65. The internal diameters of the longitudinal passage 67 recommended here are between 1-4 mm, and for the longitudinal passage 77 between 2-6 mm. It has been observed that the different inner diameters of the passages 67 and 77 favorably affect the development of the required mixing or turbulence between the aerosol that is developed from the heated tobacco flavor material and the air drawn in from the outer space around the cigarette 23 during the smoking of the cigarette and thus lead to improved tobacco aroma creation and allow a larger area than just one end of the filter 71 to be exposed to the mixed aerosol. The tobacco aroma developed by heating the tobacco aroma material 61 is primarily in the vapor phase within the cavity 79 and becomes a visible aerosol after mixing in the passage 77. In addition to the above described first free passage filter 65 having a longitudinal passage 67, there are other designs which can produce the required mixing of the vapor phase of the tobacco aroma with entrained air, which include those embodiments where the first free-pass filter is made in the form of a filter with a large number of small chokes, i.e. the first free-pass filter can be in the form of a honeycomb or a metal plate which has a larger number of openings.

Air is preferably drawn into the cigarette 23 mainly through the tobacco paper 57 and wrapping paper 69, in the transverse or radial direction, and not through the return filter 63 in the longitudinal direction. As explained below, it is still preferable to allow the air to flow through the return filter when drawing the first smoke on the cigarette in order to reduce resistance to drawing ("RTD"). It is understood that drawing air into the cigarette 23 in the longitudinal direction results in the aerosol, developed by heating the tobacco paper 57 by means of the heating elements 43 radially arranged around the tobacco paper, not being completely removed from the cavity 79. Here, it is preferred that the tobacco flavor is produced almost exclusively as a function of the composition of the tobacco paper and the energy level of the heating elements 43. Accordingly, the portion of the air stream through the cigarette resulting from the longitudinal flow through the return filter 63 should preferably be minimal during smoking, except during the first smoke inhalation. Furthermore, the return filter 63 minimizes the backflow of aerosol from the cavity 79 after heating the tobacco flavor material 61, so that the possibility of damage to the components of the lighter 25 due to the backflow of aerosol from the cigarette 23 is reduced to a minimum.

The supporting part or plenum 59 which carries the tobacco flavor material 61 enables separation of the heating elements 45 and the flavored material, transfers the heat produced by the heating elements to the flavored material, and maintains the cohesion of the cigarette after smoking. Recommended bearing members 59 include those composed of non-interwoven carbon fibers, preferred for their thermal stability. Such carriers are described in more detail in current US Patent Application Ser. no. 07/943,747, filed Sep. 11, 1992, which is incorporated herein by reference. Such nets should preferably have a thickness of approximately between 0.05 mm and 0.11 mm and be composed of non-woven carbon fibers (with a basis weight in the range of approximately 6 g/m2 to approximately 12 g/m2 and with a fiber diameter between approximately 7 m and 30 m). The length of the fibers should allow the net to withstand the tensile stresses that occur during processing. The mesh should preferably contain a binder suitable for use in electronic smoking devices (ie with properties that are acceptable).

Other load-bearing parts 59 include lightweight open-mesh metal screens or perforated metal foils. For example, a screen having a mass in the range of approximately 5 g/m 2 to 15 g/m 2 and wire diameters of approximately 0.038 mm (about 1.5 mil) to approximately 0.076 mm (about 3.0 mil) is used. Another embodiment of the screen is made of foil (e.g. aluminum) 0.0064 mm (about 0.25 mil) thick with perforation diameters ranging from approximately 0.3 mm to approximately 0.5 mm, in order to reduce the weight of the foil by approximately 30% and 50%, respectively. The perforation of such a film is preferably made in a zigzag pattern or discontinuously, with breaks (i.e. the perforation is not flat) in order to reduce lateral heat dissipation from the tobacco flavoring material 61.

Such metal screens and foils are incorporated into the cigarette 23 in a variety of ways including, for example, (1) casting a tobacco flavor suspension onto a strip and covering that suspension with a screen or foil carrier before drying, and (2) gluing, in layers , carrier in the form of a sieve or foil on the base layer with tobacco aroma in the form of a leaf or net using a suitable adhesive. Due to the possibility of an electrical short circuit in or between the heating elements 43 in the case where a metal bearing part is used, such supports should generally not be in direct contact with the heating elements. To achieve electrical isolation between the metal support 59 and the electrical heating elements 43 in the case where a metal support part is used, suitable binders and paper of low basis weight, such as wrapping paper 69, are preferably used.

The tobacco paper (weave) 57 recommended here is formed using the paper making process. In this process, the tobacco in strips is washed with water. Dissolved substances are used in the later stage of coating. The remaining (extracted) fiber is used in the production of the basic knitted structure. Carbon fibers are dispersed in water and sodium alginate is added. Any other hydrocolloid that does not react with tobacco flavoring smoke, is soluble in water, and has a suitable molecular weight to impart strength to the tobacco paper 57 may be added in place of the sodium alginate. This solution is mixed with a suspension of extracted tobacco fibers and aromas of choice. The resulting mixture is placed wet on the wire and the thread is passed along the remainder of the conventional papermaking machine to form the base weave. Soluble substances removed by washing the tobacco strips are applied as a coating to one side of the base fabric, preferably with the aid of a standard roll-back coating device installed after a roller or "Yankee" dryer. Soluble tobacco/tobacco dust or particles should preferably vary in the ratio range of 1:1 to 20:1. The suspension can be applied to the base fabric (knitting) by casting or drawing. Alternatively, the coating process can be carried out separately. During or after the coating phase, flavorings common in the tobacco industry (cigarette production) are added. In order to improve the properties of the coating suspension, pectin or another hydrocolloid is added, preferably in the range of 0.1 to 2.0%.

Regardless of which type of carrier 59 is used, the tobacco flavor material 61, which is applied to the inner surface of the carrier, releases the aroma when heated and has the ability to adhere to the carrier surface. Such materials include continuous (continuous) sheets, foams, gels, dried suspensions or spray-applied dry suspensions, which preferably, although not necessarily, contain tobacco or tobacco products, and are described in more detail in the aforementioned US Patent Application Ser. no. 07/943,747. It is recommended that some humectant, such as glycerine or propylene glycol, be added to the tobacco paper 57 during processing in amounts of 0.5% to 10% by weight in relation to the weight of the paper. The humidifier enables the formation of a visible aerosol by acting as an aerosol precursor.

When a smoker emits an aerosol containing tobacco flavor smoke and a humidifier, the humidifier condenses in the atmosphere, and the condensed humidifier leads to the appearance of normal cigarette smoke.

Since the tobacco flavoring material 61 of the present invention is applied to the surface of the carrier 59, its flavoring properties can be varied widely to allow the flavoring profile to be selectively varied from one puff to the next. For example, the tobacco flavoring material 61 adjacent to the first heating element 43 may contain a first amount or type of flavoring agent, while the material adjacent to the second heating element may contain a second different amount or type of flavoring agent. In this way, the delivery of flavored tobacco smoke to the smoker can be selectively varied or determined by using different profiles of tobacco flavoring material applied to the surface of the carrier material. The smoker can, for example, insert a cigarette 23 into the lighter 25 so that it is in a certain position with respect to the permanent heating elements, if it is desired that a certain heater heats a predetermined part of the non-uniformly distributed material with tobacco aroma.

Additionally, the flavored tobacco smoke can be selectively varied in accordance with the present invention by supplying a controlled amount of energy to the heating elements 43. For example, if the amount of energy supplied to the first heating element 43 (e.g. 20 Joules) is greater than the amount supplied to the second (eg 15 Joules), then the temperature reached by the first heater is generally higher than the temperature of the second heater. Because of this, the first heating element generally produces more flavored tobacco smoke than the second heating element. In this way, the amount of flavored tobacco smoke can be selectively controlled by varying the amount of energy from one puff to the next.

The cigarette 23 is preferably of substantially constant diameter throughout its length and, like a conventional cigarette, has a diameter between approximately 7.5 mm and 8.5 mm, so that a smoker using the smoking device 21 has a similar mouthfeel to a conventional cigarette. In the embodiment proposed here, the cigarette 23 has a length of 58 mm, end to end, which enables the use of standard packaging machines in the process of packaging these cigarettes. The common length of the filter nozzle 71 and the second filter with a free passage 73 should preferably be 30 mm. The filter paper 75 should extend 5 mm over the end of the second free-pass filter 73 and over the tobacco paper 57. A length of tobacco paper 57 of 28 mm is recommended. The tobacco paper 57 is carried at the opposite ends by means of the return filter 63, the recommended length of which is 7 mm, and the first filter with a free passage 65, which should preferably have a length of 7 mm. The cavity 79 defined by the tobacco paper 57, the return filter 63 and the free passage filter 63 has a length of 14 mm.

When the cigarette 23 is inserted into the throat 27 at the front end 29 of the lighter 25, it abuts or nearly abuts the inner lower surface 81 of the spacer 49 of the heater assembly 39, as seen in Figure 3A, immediately adjacent to the passage 47 which is connected to the sensor 45 which reacts to smoke intake and with an opening 55 for the light sensor 53. In this position, the cavity 79 of the cigarette 23 is located directly next to the heating elements 43, and mostly the entire part of the cigarette that includes the second filter with a free passage 73 and the filter whistle 71 is located outside the lighter 25 The parts of the heating elements 43 are preferably directed radially inwards so that it is possible to hold the cigarette 23 in a certain position in relation to the heater 25 and that the transfer of heat between the heater and the tobacco paper 57 is enabled, either directly or through the wrapping paper 69. Therefore , the cigarette 23 should be squeezable in order to allow the heating elements to be pressed into the sides of the cigarette.

The flow of air through the cigarette 23 is achieved in several ways. For example, in the embodiment of the cigarette 23 shown in Figures 4A and 4B, the wrapping paper 69 and the tobacco paper 57 are sufficiently air permeable to achieve the desired resistance to draw (RTD) so that when the smoker draws smoke on the cigarette, air flows into the cavity 79 transversely or radially through wrapping paper and tobacco paper. As noted above, an air-permeable non-return filter 69 may be applied to achieve longitudinal air flow into the cavity 79 .

If desired, transverse air flow into the cavity 79 can be achieved by a series of radial perforations (not shown) in the wrapping paper 69 and the tobacco paper 57 in one or more zones bordering the cavity. Such perforations have been found to enhance the production of flavored tobacco smoke and aerosols. Perforation is performed on tobacco paper 57 with a density of 1 hole per 1-2 square millimeters with a hole diameter of 0.4 mm to 0.7 mm. This achieves the porosity of COREST between 100-500. Wrapping paper 69 has a permeability of 100 to 1000 COREST. Of course, in order to achieve the desired smoking characteristics, such as drag resistance, the perforation density and the corresponding opening diameter other than those mentioned can be used.

Transverse flow of air into the cavity 79 can also be made possible by punching a perforation through both papers, i.e. through the wrapping paper 69 and the tobacco paper 57. In forming the cigarette 23 with such a perforation, the wrapping paper 69 and the tobacco paper 57 are perforated together after being placed one on each other, or they are drilled separately and then placed on top of each other so that the perforations are aligned or overlapped.

The embodiment of the heater assembly 39 proposed here is seen in Figures 3A and 3B. A modified version of the heater assembly 39A with a combined spacer and base element 49A is shown in the disassembled state in Figure 5.

Element 49A of heater assembly 39A replaces spacer element 49 and base 50 of heater assembly 39 shown in Figure 3A. The basic functions of providing a space for accepting the cigarette 23 and installing heating elements for heating the cigarette can, of course, be achieved with heater assemblies other than those shown in Figures 3A-3B and 5.

According to Figures 3A-3B, the heater assembly 39 is placed in the throat 27 of the lighter 25. The cigarette 23 is inserted, first the return filter 63, into the throat 27 of the lighter 25 in the generally cylindrical space of the heater assembly 39 which space is defined (bounded) by the annular cover 83 which has one open end for receiving a cigarette, one optional cylindrical heater sleeve 85, one cylindrical air sleeve 87, a heater assembly 89 together with heating elements 43, an electrically conductive pin or common conductor assembly 91, which serves as a common conductor for the heating elements of the assembly heater, and the spacer element 49. The lower inner surface 81 of the spacer element 49 stops the cigarette 23 in the desired position in the heater assembly 39 so that the heating elements 43 are placed all the way to the cavity 79 in the cigarette. In the heater assembly 39A shown in Figure 5, the lower inner surface 81A of the element 49A stops the cigarette 23 in the desired position in the heater assembly.

Essentially, the entire heater assembly 39 is located inside and fixed by means of a tight fit in the housing 31 of the front part 33 of the lighter 25. The front edge 93 of the cover 83 is preferably located on the front end 29 of the lighter 25 or is slightly extended over it, and includes an internal bevel or a rounded part to achieve the guidance of the cigarette 23 in the heater assembly 39. The parts of the heating elements 43 of the heater assembly 89 and the pins 95 of the pin assembly 91 are fixed around the outer surface 97 of the spacer element 49 in a frictional fit by means of a ring 99. The rear ends 101 of the heating elements 43 a the rear ends 103 of, preferably, pins 95 are welded to pins 104 which tightly fit into an extension that passes over the lower outer surface 105, visible in Figure 3B, of the base 50 through holes 107 in the base provided for connecting the control assembly 41 and the power source 37 The pins 104 should be sufficiently attached to the base 50 so that they block the flow of air through the holes 107. The pins 104 fit in o suitable couplings (bearings) (not shown), thereby enabling the fastening and carrying of the heater assembly 39 in the lighter 25, and thus creating the possibility of connecting these couplings with different electrical elements by means of conductors or printed circuits. The other two pins 95 provide additional support for strengthening the pin assembly 91. The passage 47 in the spacer element 49 and the base 50 is connected to the sensor 45 which reacts to the intake of smoke and to the sensor 53 which determines the presence or absence of a cigarette 23 in the lighter 25.

In a similar way, in the heater assembly 39A shown in Figure 5, the parts of the heating elements 43 of the heater 89, and the pins 95 of the pin assembly 91 are fixed around one outer surface 97A of the element 49A by means of a friction disc using a ring 99. The rear ends 101 of the heating elements 43 and the rear ends 103 of, preferably, two pins 95 pass over the lower outer surface 105A of the element 49A for connecting the control circuit 41 and the power source 37.

The element 49A is preferably formed by means of a flanged end 109 in which at least two grooves or bores 107A are provided through which the rear ends 103 of the two pins 95 pass over the lower outer surface 105A. The other two pins 95 provide additional strength to the pin assembly 91. The rear ends 101 of the heating elements 43 are bent to conform to the flange end 109 and pass over the lower outer surface 105A radially outside the outer edge 111 of the flange end. The passage 47 in the element 49A connects the sensor 45 which reacts to the drawing in of smoke and the light sensor 53 determines whether the cigarette 23 is placed in the lighter 25 or not.

The heater 89, shown in Figure 3A, 5 and 6, is preferably made from a single, laser-cut sheet of a so-called superalloy that has a combination of high mechanical strength and surface wear resistance properties at high temperatures. The plate is cut or is shaped either by cutting (stamping) or drilling or, even better, by means of a CO2 laser, to obtain the general outline (contour) 115 of the heater 89, visible in Figure 7.

In the pattern 115, the heater elements 43 are connected to each other at their rear ends 101 by means of the rear part 117 of the cut-out heater plate 115 and, at the front ends 119, by means of the part forming the front part 121 of the heater 89. The two side parts 123 extend between the rear part 117 and of the front part 121. The back part 117 and the side parts 123 serve, while not yet forming part of the finished heater 89, to handle the cut plate 115 during processing.

After the plate 115 is formed, each heating element 43 has a wide part 125 which, in the finished heater 89, is located directly next to the tobacco paper 57, and a narrow part 127 for making electrical connections with the control assembly 41. If desired, the narrow part 127 of each heating element 43 may be provided with extended contacts 129 near the rear end 101 to allow welding with pins 104 or to be fixed in connectors (seats) (not shown) for electrical connection with the control circuit 41 .The basic shape of the heater plate 115 is further processed, preferably by further laser cutting, to produce a serpentine "footprint" 131, as seen in Figures 6 and 8, from the wide portion 125. Of course, if desired, footprint 131 can be cut at the same time as the basic shape 115.

It is recommended that the cut or patterned plate be electropolished in order to level and smooth the edges of the individual heating elements 43. The smooth edges of the heating elements 43 enable the cigarette 23 to be inserted into the lighter 25 without sticking.

The cut shaped plate is rolled (wrapped) around a holder (not shown) to form a cylindrical shape. The rear portion 117 as well as the side portions 123 are then cut off and the edges 133 of the front portion 121 are welded together to form a single, integral heater 89, as shown in Figure 6.

Heater 89 can be made in any other suitable way available to us. For example, according to one alternative method, the heater 89 is formed from a plate that is initially formed into a tube (not shown) and then cut to produce a plurality of heating elements as in Figure 6. Additionally, the heater 89 can be formed from a number of individual heating elements 43 which are connected, for example by spot welding, to a common ring or strip (not shown) which has the same functions as the front part 121, i.e. it serves as a common electrical conductor for the heating elements and their mechanical bracket. Further, the front portion 121 of the heater 89 may be welded or otherwise attached to a calibration ring (not shown) having an inner diameter substantially equal to the cigarette 23. The calibration ring allows the heater assembly to be held in the desired shape and increases strength.

The pin assembly 91 shown in Figure 9 is preferably formed by one of the methods similar to the process described in connection with the heater 89. Like the heater 89, the individual pins 95 as well as the strip part for forming the front part 135 of the pin assembly 91 are also cut from a flat sheets of electrically conductive material, then rolled and welded to form a cylindrical shape. The pin assembly 91 is formed with an inner diameter substantially equal to the outer diameter of the heater 89. The front part 121 of the heater 89 is then inserted into the front part 135 of the pin assembly 91 and the two parts are secured together, preferably by spot welding, so that the four pins 95 located in the free space between adjacent pairs of heating elements 43. As can be seen in Figure 3B, the four pins 95 (of which only two are connected electrically to the pins 104 which in the proposed embodiment extend through the base 50) are preferably radially located at an angle of 22.5° in relation to the adjacent heating element 43 (out of a total of eight heating elements) and its connected pin 104 extending through the base.

The various designs of the lighter 25 in accordance with the present invention are all intended to produce and deliver to the smoker an adequate amount of flavored tobacco smoke under standard conditions of use. More precisely, the delivery to the smoker of between 5 and 13 mg, preferably between 7 and 10 mg, of aerosol in all 8 smokes is considered here as a desirable amount, whereby one inhalation of smoke contains 35 ml for two seconds. It has been found that to achieve such a supply, the heating elements 43 should be able to reach a temperature between 200°C and 900°C when there is heat transfer between the heater and the cigarette 23. Furthermore, the heating elements 43 should preferably consume between 5 and approximately 40 Joules of energy, preferably between 10 Joules and 25 Joules, more preferably around 15 Joules. Lower energy consumption is achieved with heating elements that are bent inwards in the direction of the cigarette 23 to improve heat transfer conditions.

Heating elements 43 with the desired characteristics preferably have an active surface between approximately 3 mm2 and 25 mm2 and a resistance of approximately 0.5 Ω to approximately 3.0 Ω. It is even more advantageous if the heating elements 43 have a resistance between approximately 0.8 Ω and 2.1 Ω. Of course, the resistance of the heater is also conditioned by a certain energy source 37 that is used to deliver the necessary electrical energy to heat the heating elements 43. For example, the above resistances of the heating element correspond to designs where the electrical energy is provided by four serially connected nickel-cadmium battery cells with a total with no-load voltage of approximately 4.8 to 5.8 volts. If, alternatively, six or eight such series-connected batteries are used, the heating elements 43 will have a resistance between approximately 3 Ω and 5 Ω and between 5 Ω and 7 Ω, respectively.

The materials of which the heating elements 43 are made are preferably selected to ensure reliable repeated use of at least 1800 on/off cycles without failure. The heater assembly 39 is preferably discarded independently of the igniter 25 including the power source 37 and control assembly, and is preferably discarded after 3600 cycles or more. Heating element materials are selected based on their resistance to oxidation and general lack of reactivity to ensure that they will not oxidize or otherwise react with the cigarette 23 at any temperature that may occur. If desired, the heating elements can be hermetically sealed in a material of poor thermal conductivity, such as a ceramic material, to further prevent oxidation and reaction.

Based on these criteria, materials for electric heater elements include alloyed semiconductors (eg silicon), carbon graphite, stainless steel, tantalum, metal ceramic matrices and metal alloys, such as alloys containing nickel, chromium and iron. A silicon semiconductor material doped with phosphorus impurities to a level in the range of 5 x 1018 impurities/cm3 to 5 x 1019 impurities/cm3, corresponding to a specific resistance in the range of approximately 1 x 10-2 Ω-cm to approximately 1 x 10-3 Ω -cm, is described in current U.S. Pat. patent application ser. no. 07/943,505, which is incorporated by reference. Suitable metal-ceramic matrices include silicon carbide aluminum and silicon carbide titanium. Oxidation-resistant intermetallic compounds such as nickel aluminides and iron aluminides are also suitable.

It is even more advantageous that the electric heating elements 43 are made of a heat-resistant alloy that exhibits a combination of properties of high mechanical strength and resistance to surface wear at high temperatures.

The heating elements 43 are preferably made from a material that has high strength and surface stability at temperatures up to approximately 80% of its melting point. Such alloys include those commonly referred to as superalloys and are generally based on nickel, iron or cobalt. Advantageously, the super-alloy of the heating elements 43 includes aluminum to further improve the characteristics of the heating element (eg resistance to oxidation). Such material is available from the manufacturer Haynes International, Inc. of Kokomo, Indiana, under the name(s) of Haynes 214 alloy. This high-temperature material contains, among other elements, about 75% nickel, about 16% chromium, about 4.5% aluminum and about 3% iron by weight.

As noted above, the individual heating elements 43 of the heater 89 preferably include a "footprint" shaped portion 131 with a plurality of interconnected curved zones - generally S-shaped - to increase the effective resistance of each heating element. The sinuous outline of the footprint 131 of the heating elements 43 increases the electrical resistance without increasing the overall length or reducing the cross-sectional width of the heating element. Heating elements 43 having a resistance in the range of approximately 0.5 Ω to approximately 3 Ω and whose footprint length is adapted to fit into the heater assembly 39 of Figure 3A and the heater assembly 39A of Figure 5 preferably have N interconnected zones S-shaped, wherein N is in the range of about three to about 12, more preferably between six and ten.

If the heater footprint 131 shown in Figure 8 is first cut into the shape of the wide portion 125 of Figure 7, such that the wide portion has a width W1, a length L1, and a thickness T, the resistance from one end 125' to the opposite end 125'' of the wide portion is determined is the equation:

[image]

where means the specific resistance of the particular material used. After forming the footprint 131, the resistance of the footprint is increased since the effective electrical resistance length of the heating element 43 is increased while the cross-sectional area is reduced. For example, after the footprint is formed in the heating element 43, current flow through the heating element is along path P. Path P has an effective electrical length of approximately 9 or 10 x W1 (for nearly five full revolutions of the footprint of the heating element), opposite the initial electrical length L1. Furthermore, the cross-section has decreased from W1 x T to W2 x T. In accordance with the present invention, both of these changes, i.e., the increase in electrical length and the decrease in cross-section, tend to increase the total electrical resistance of the heating element 43, since the electrical resistance is proportional to electrical length and inversely proportional to cross-sectional area.

Therefore, by shaping the footprint 131 in the heating element 43, a reduction in the volume of the conductive material used is achieved while at the same time achieving a predetermined resistance over a given heating surface, for example, 3 mm2 to 25 mm2. The above characteristic of the subject invention provides at least three advantages.

First, for a given resistance, the heating element 43 is formed from a rectangular plate having a smaller length than would be necessary if it were formed as a linear element. This enables a more compact design of the heater assembly 39 and the production of the lighter 25 with lower production costs.

Second, given that the energy required to heat the heating element 43 to the set operating temperature in still air increases as the mass of the heating element increases, the design of the heating element with turns is energetically favorable, since it enables the achievement of the set resistance at a reduced volume. For example, if the volume of the heating element 43 is reduced twice (a factor of two), then the mass is also reduced in the same proportion. In this way, given that the energy required to heat the heating element 43 to the set operating temperature in still air is mainly proportional to the mass and heat capacity of the heating element, reducing the volume by a factor of two also reduces the necessary energy by two times. This results in a more energy efficient heating element 43.

The third advantage of the reduced volume of the heating element 43 of the coil design is related to the time duration of the reaction of the heating element. Time response is defined as the length of time it takes for a specific heating element 43 to change the first (initial) temperature to another, higher temperature as a reaction to the supplied (input) energy. Since the time response of the heating element 43 is generally proportional to its mass, it is desirable that a heating element with a reduced volume also has a reduced response time. For this reason, the heating elements 43 in the spiral version, apart from their compactness and energy efficiency, also have the ability to heat up to the working temperature more quickly. This characteristic of the subject invention also results in a better utilization of the heating element 43.

In this way, by making more turns in the heating elements 43 (eg in the form of a bend), the resistance of the heating element is increased without the need to increase the length or reduce the cross-sectional area of the heating element. There are, of course, other models of the heating element 43 besides the one shown in Figure 8, by means of which the principles used in the above design can be applied, thereby also achieving a compact and efficient heating element.

The footprint 131 is etched into the heating elements 43 using any compatible process, preferably a laser (preferably a CO2 laser). Due to the small geometrical sizes that occur with the heating elements 43 with turns (for example, the gap B in Figure 8 should be on the order of 0.1 mm to approximately 0.25 mm), laser cutting has an advantage over other methods for cutting the footprint 131. Whereas that laser energy is adapted for concentration on small volumes, laser energy enables versatile, fast, accurate and automated processing. In addition, laser processing reduces the induced stresses of the material being cut, as well as the surface of the material under the influence of heat (i.e. oxidized material) compared to other cutting processes (eg electric discharge processing). Other compatible processes include electric discharge machining, precision embossing, chemical etching, and chemical milling (grinding). It is also possible to form the footprint 131 by conventional methods using a cutting tool, although this alternative is less attractive due to the wear of the cutting tool, at least in the winding designs.

In addition to cutting the heating elements 43 with turns, the laser can also be very conveniently used for the efficient joining (bonding) of different components of the lighter (preferably a laser with yttrium-aluminum-garnet (YAG)). For example, the heater 89 and pin assembly 91 are preferably spot welded to each other using a CO2 or YAG laser. In addition, the rear ends 101 or extended contacts 129 of the heating elements 43 are preferably also laser welded to the electrical connections (pins) 104 in the base 50 or to corresponding circular elements or sockets. Of course, there are also various conventional connection methods for connecting the different components of the lighter to each other.

In accordance with the present invention, thermally induced stresses in the heating elements 43, which could cause damage, are reduced to a minimum. As seen in Figure 6, the rear ends 101 (or extended contacts 129) which are welded to the pins 104 or other electrical assemblies or components, and the heat producing portions of the footprint 131, are formed as a single heating element 43, thereby avoiding the need to weld separate parts of the footprint and end parts. Such welding has been found to produce unwanted distortion during heating of the heating elements. The longitudinal central axes of the end parts 101 or contacts 129 should preferably be aligned with the central axes of the footprints 131. It has also been observed that misaligned central axes cause distortions during heating of the heating elements. Furthermore, the opposite ends 131' and 131'' of the footprints 131 preferably symmetrically contact the uncurved parts of the heating element 43, i.e. each point in the same direction. The symmetry of the ends 131' and 131'' tends to prevent the ends of the footprints 131 from buckling in opposite directions during heating and thus from damaging the footprint. The transitional surfaces 137' and 137'' at the ends 131' and 131'' of the footprint 131, and between the non-curved parts of the heating element 43 and the ends are preferably beveled as shown in Figure 6. Bevelled transitional surfaces 137' and 137'' they also reduce thermally induced stresses.

Heating elements 43 and heater assembly 39 have some additional features that avoid problems related to heating and reheating. For example, during heating, the heating elements 43 show a tendency to expand. Since the heating elements 43 are secured between the stationary front end 135 of the pin assembly 91 attached to the front 121 of the heater 89 and the ring 99 near the rear ends 101 of the heating elements, expansion of the heating elements will result in either the desired bending of the heating elements inwardly in the direction of the cigarette 23 or in unwanted bending outwards opposite to the cigarette. During external bending, a thermal gap will appear between the heating element 43 and the cigarette 23. This leads to inefficient and inconsistent heating of the tobacco paper 57 due to a change in the degree of mutual contact between the surfaces of the heating element and the cigarette.

In order to avoid bending in the outward direction, the individual heating elements 43 of the heater 89 are preferably shaped to have the desired inward curvature, as seen in Figure 3 A. The inward bending ensures a tight fit and good thermal contact between the heating elements 43 and cigarettes 23. The inwardly bent shape of the heating elements 43 is achieved in any of a number of possible ways, such as forming cylindrical heaters, such as that shown in Figure 6, on a mold (not shown) having the desired inward curvature. It is recommended that an inward curved shape be made in the heating elements 43 during cutting and pressing (not shown).

Before forming the heater 89 into a cylinder. The shape with internal distortion of the heating elements 43 will result in further bending inward when the heating elements expand during heating. This curvature should preferably be relatively mild along the entire length of the footprint 151. Beveled transition surfaces 137' 137'' can be more curved than the sensitive footprints 131. In this way, the concentration of thermal stresses on the more sensitive parts of the heating elements 43 is avoided.

If desired, a ring (not shown) is placed around the footprint 131 of the heating elements 43. This ring serves as a heat sink and, when the footprints 131 of the heating elements 43 expand during heating, the footprints are forced to expand inwardly, towards the cigarette 23.

In addition to the previously described heater 89, the heater assembly 39 shown in Figure 3A also includes a spacer element 49 and a heater assembly base 50. The spacer element 49, shown individually in Figures 10A-10C, has a cylindrical outer surface 97 to which the pins 91 and heating elements are attached. 43 attached with a friction fit using a ring 99.

The spacer element 49 further includes a floor wall 139, whose lower inner surface 81 serves to limit the further movement of the cigarette 23 into the lighter 25 so that the cigarette comes into the correct position in relation to the heating elements 43, and a cylindrical inner wall 141 to enable the passage of the cigarette in spacer element. In the floor wall 139, a part 47' of the passage 47 is formed for connection with the sensor 45 which reacts to the inflow of smoke. The part 47' is preferably in the form of a hole or bore that passes through the floor wall 139 parallel to the central axis of the spacer element 49. Likewise, an opening 55 for the light sensor 53 is made in the floor wall 139. The damper 143 for the first insertion extends from the outer surface 97 of the spacer element 49 to the part 55' of the opening. Throat 143 for the first draw of smoke helps achieve the desired draw resistance (RTD) during the first draw of smoke on the cigarette 23 by opening an additional passage for the air flow from the zone around the cigarette to the zone adjacent to the return filter 63. Given that the tobacco paper 57 and wrapping paper 69 tend to restrict the flow of air into the cigarette 23 until the heating element 43 heats one zone on the cigarette, the choke 143 ensures the flow of air to the zone of the heater assembly 39 by means of the return filter 63 of the cigarette. The return filter 63 allows a sufficient amount of air into the cigarette 23 to achieve a lower resistance to draw (RTD) than would otherwise be the case. In any case, the return filter 63 should be as compact as possible (dense, tight) while at the same time enabling the aforementioned air flow during the first inhalation, so that the aerosol that remained in the cavity 79 after the inhalation of smoke on the cigarette 23 does not pass back into igniter through the return filter. After the first inhalation of cigarette smoke 23, part of the tobacco paper 57 and wrapping paper 69 that was heated by turning on the heating element becomes more permeable to air. Therefore, the airflow through the first draw choke 143 and the return filter becomes irrelevant for all smoke draws on the cigarette 23 after the first draw.

The base 50, as seen in Figures 11A-11C, is generally cylindrical in shape and includes a floor wall 151, pins or guides 104 for connection to the pins 95, and heating elements 43 that pass through holes 107 made in the floor wall and pass over the lower outer area of 105 bases. The base 50 is preferably made with a cylindrical outer surface 153 and a cylindrical inner wall 155, wherein the inner wall has a diameter that is greater than the outer diameter of the spacer element 49, and generally the same as the outer diameter of the ring 99. The spacer element 49 is held in a certain position in relative to the base 50 by means of a frictional fit between the inner wall 169 of the air sleeve 87, the ring 99 and the outer surface 97 of the spacer element. The method of securing the air sleeve 87 to the base 50 is explained below. The spacer element and the base 50 can be fixed with other, or with additional means such as glue, screws or snap-on fasteners. In addition, one or more ridges and grooves (not shown) may be formed on the spacer and base 50 to provide a desired mutual position of the spacer and base at a certain angle. A portion 47'' of the passage 47 is formed in the floor wall 151 and preferably extends from a point near the center of the base 50 to the peripheral edge of the base. If desired, the part 47'' can be partly made in the form of a groove on the inner surface 157 of the floor wall, whereby this groove becomes air-tight after the installation of the spacer element 49. It is recommended that the part 47'' be in the form of longitudinal and radial holes which intersect with each other made in the floor wall 151. In the floor wall, a part 55'' of the opening 55 is made. would form passage 47 and opening 55.

Element 49A of the heater assembly 39A in the embodiment of Figure 5 is seen further in Figures 12A-12D. The element 49A has a cylindrical outer surface 97A to which the pins 95 and the heating elements 43 are fixed by means of a ring 99. The element 49A also has a floor wall 139A, the inner surface 81A of which serves to block the further movement of the cigarette 23 into the lighter 25 so that the cigarette is in the correct position in relation to the heating elements 43 and to the cylindrical inner wall 141A of the element, in order to enable the passage of cigarettes into the element. A choke for the first feed (not shown) can also be made in element 49A. In the lower wall 139A, there is a passage 47A for connection with the sensor 45, which is activated by pulling it in. The passage 47A is preferably in the form of a hole or bore that passes through the floor wall 139A parallel to the center of the element 49A. In the floor wall 139A, there is also an opening 55A for the light sensor 53. As previously stated, the rear ends 101 of the heating elements 43 and the rear ends 103, preferably at least two pins 95, pass over the outer surface 105A of the floor wall of the element 49A for connection to the control assembly 41 and the power source 37. The element 49A is preferably made with a flanged end 109 in which at least two grooves or holes 107A are made through which the rear ends 103 of the two pins 95 pass so that they protrude beyond the outer surface 105A of the floor wall. The rear ends 101 of the heating elements 43 are bent to match the shape of the flange end 109, and pass over the outer surface 105A of the floor wall in a radial direction beyond the outer edge 111 of the flange end. An air sleeve 87A fits on the outer edge 111 of the flanged end 109 in order to additionally fix the ends 101 of the heating elements 43 in their position.

Unless otherwise indicated, further discussion of the smoking device 21 relates, for ease of reference, primarily to the components of the heater assembly 39 shown in Figures 3A-3B. It will be understood, however, that this consideration may apply generally to the embodiment of the heater assembly 39A shown in Figure 5, as well as to other embodiments not specifically shown or discussed herein. As previously noted, the heater assembly may include other devices that may perform various functions of the heater assembly, such as creating a space near the heating elements for heating the cigarette. Figure 13 shows a side view of the ring 99 that secures the heating elements 43 and pins 95 around the outer surface 97 of the spacer element 49 from Figure 3A. The inner diameter of the ring 99 is large enough to allow the ring to surround and secure the heating elements 43 to the cylindrical outer surface 97 by a frictional fit.

Longitudinal grooves 159 are disposed at a mutual angle of 90° around the inner periphery of the ring 99 to accept generally thicker pins 95 so that the ring can embrace and secure the pins to the outer surface 97.

The air sleeve 87 is placed with the first end 161 on the base 50, and with the second end 163 on the cover 83. The first end 161 of the air sleeve 87 is preferably made with an outer edge (ridge) 165 that engages in an inner groove 167 on the inner wall 155. base 50. In a similar way, the other end 163 of the air sleeve 87 is, if possible, made with an outer ridge 171 for engagement in the inner groove 173 on the inner edge 175 of the cover 83. The air sleeve 87A in the embodiment of the heater assembly 39A shown in Figure 5 is differs from the design of the air sleeve 87 shown in Figure 3 in that the first end 161A of the air sleeve 87A is preferably made with an internal groove 165A into which the outer edge 167A engages on the outer edge 111 of the flange end 109 of the element 49A. Parts of the heating elements 43 near the rear ends 101 pass between the mutually engaged parts of the element 49A and the air sleeve 87A.

As will be seen from further consideration in connection with Fig. 17, if it is desired to increase air flow, one or more radial holes or bores may be made through portions of heater assembly 39 such as air sleeve 87, preferably at locations along the air sleeve where the air flow is not blocked or forced to travel in a tortuous path at the cover 85 or spacer 49 before reaching the cigarette 23.

The cover 83 of the heater assembly 39, seen in Figure 3A, and the cover 83A of the heater assembly 39A, seen in Figure 5, are similar in every respect except that the cover 83 has an inner wall 177 longer than the inner wall 177A of the cover 83A. The inner diameter of the inner wall 177 of the cover 83 should not be larger than the outer diameter of the cigarette 23, but preferably a little smaller, so that after insertion into the lighter 25 the cigarette is pressed and held firmly in place. A longer inner wall 177 of the cap 39 is recommended to provide additional support to the cigarette 23. For ease of following this consideration, the cap 83A is shown separately in Figures 14A-14D.

The cap 83A is formed with a plurality of longitudinal bores or passages 179A extending through the cap from the rounded or beveled front end 93A to the rear face 181A to allow air to flow into the space within the heater assembly 39A for receiving the cigarette 23, between the cigarette and the air sleeve 87. , so that a transverse (ie, radially inward) stream of air passes through the tobacco paper 57 at the footprint 131 of the heating elements 43. As seen in Figure 3A, in the recommended embodiment of the cover 83 of the heater assembly 39, the holes or passages 179 are shaped so that they are greater near the rear face 181 than they are near the front end 93, in order to achieve the desired drag resistance (RTD). In another embodiment of the cap, the longitudinal holes or bores are replaced with longitudinal grooves (not shown) which are formed on the inner wall of the cap.

Referring to Figures 14A-14D, a circumferential groove 183A is formed on the rear face 181A to receive and support the heater guard sleeve 85 (optional installation), shown separately in Figures 15A-15B. The heater sleeve 85 is a tubular element that has a first and a second end, 185 or. 187, adjusted to fit into slot 183A. The circumferential groove 183A is formed at a larger radius than the bores or passages 179A to allow air to be introduced into the heater assembly 39 when the smoker takes a puff on the cigarette 23.

Cover 83, shown in Figure 3A, may be cast or machined. It is recommended that the cap be cast in one piece, such as cap 83A in Figure 5. If the cap is machined, then it is formed in two parts, an outer part 83' and an inner part 83'', as seen in FIG. Figure 3A, which connect to each other. Before assembling the inner part into the outer part 83', a circumferential recess is made on the outer surface of the inner part 83'', which, after joining the inner and outer parts, forms a groove 183. This avoids the need for machining the one-piece cover with the machined two-part cover 83 of groove shaping 183.

The removal and replacement of the sleeve of the heater 85 with a new sleeve is performed by the smoker at desired intervals (for example, after smoking 30-60 cigarettes 23). The heater sleeve 85 prevents exposure of the inner wall 169 of the air sleeve 87 to the residual aerosol produced in the zone between the heating elements 43 and the air sleeve. Instead, that aerosol acts on the heater sleeve 85.

The heater sleeve 85 is made of a material such as paper or heat-resistant plastic, and the smoker changes it after smoking a number of cigarettes. Thus, in contrast to a "tube-in-tube" embodiment including an aerosol protection tube that is placed on the flavoring component and that is discarded together with that component after it has been used for smoking, the heater sleeve 85 of the subject smoking device 21 is adapted for multiple use. Accordingly, the production of cigarette 23 is simplified, and the amount of material discarded after each cigarette is reduced. Figure 16 schematically shows the flow of air in the heater assembly 39 and the cigarette 23 when the smoker draws in smoke at the filter nozzle 71. Air is drawn in, as a result of suction on the filter nozzle 71, through the longitudinal holes or passages 179 into the interior of the heater assembly 39 between the air sleeve or of the sleeve of the heater (not marked with a number in this picture), passes the heating elements (not shown) in contact with the cigarette 23, and enters the cavity 79 through the air-permeable outer wrapping paper 69 and tobacco paper 57 (or through the perforation made on them) in a cigarette. From the cavity 79, the air flows further into the longitudinal passages 67 in the first filter with a free passage 65, the longitudinal passages 77 in the second filter with a free passage 73, and through the filter nozzle 71 to the smoker. The number and dimensions of the passages 179 are chosen in such a way that the optimal total amount of ingredients is delivered to the smoker. In the embodiment proposed here, six or eight passages 179 are provided in the cover 83.

As seen in Figure 17, other air passages may optionally be provided instead of or in addition to the passages 179 to allow air to enter the interior of the heater assembly 39 and the cavity 79 of the cigarette 23. For example, one or more radial passages 189 can be made in the heater assembly 39 in any desired position, usually in the air sleeve. Longitudinal passages 191 can be made in the heater assembly 39 through the base or through the base and the spacer element (not shown in the drawing).

Likewise, the passages 179 in the cover 83 may be in the form of holes or bores, as previously discussed, or longitudinal grooves formed in the inner wall 177 of the cover. As previously stated, a return filter 63 may be incorporated, if desired, to allow longitudinal flow in the cavity 79 when the smoker inhales the smoke on the cigarette.

If desired, the lighter 25 may additionally have a pointed tube (not shown) positioned within the heater assembly 39 for piercing the return filter 63 of the cigarette 23 after the cigarette has been inserted. The pipe is designed so that it ends inside the cavity 79 and enables a direct flow of air into the cavity when the smoker draws smoke on the cigarette 23. The pipe is equipped with one or more small openings (mufflers) at the introduction end, preferably on the sides of the pipe opposite the introduction end of the pipe, in order to establish a flow of air at high speed in directions that help the vortex of the air current inside the cavity. Such swirling enhances the mixing of the incoming air with the aerosol and vapor produced on the cigarette 23.

The electrical control circuit 41 of the smoking device 21 is shown schematically in Figure 18. The control circuit 41 includes a logic circuit 195, which is a specific integrated circuit or ASIC, a sensor 45 activated by smoke inhalation which serves to detect smoke inhalation on the cigarette 23, a light sensor 53 for cigarette lighter 25 detection, a liquid crystal display (LCD) 51 for indicating the number of puffs remaining on the cigarette, a power source 37 and a timing circuit 197. The logic circuit 195 may be any conventional circuit capable of performing the functions discussed herein. word. A field-programmable controller (eg, type ACTEL A1010A FPGA PL44C, manufactured by Actel Corporation, Sunnyvale, California) can be programmed to perform digital logic functions while analog functions are performed by other components, and to perform both digital and analog functions in one component, an application-specific integrated circuit (ASIC) is required. Control circuit and logic circuit characteristics similar to those of control circuit 41 and logic circuit 195 of the present invention are disclosed, for example, in U.S. Pat. Patent no. 5,060,671, which disclosure is incorporated herein by reference.

In the embodiment recommended herein, eight individual heating elements 43 (not shown in FIG. 18) are connected to the positive terminal of the power source 37 and to ground via the corresponding field effect transistor (FET) heater switches 201-208. Individual heater switches 210-208 will be turned on under the action of logic circuit 195 via connections 211-208. Logic circuit 195 provides on and off signals to individual heater switches 201-208 to turn the respective heaters on and off.

The sensor 45 which responds to the inflow of smoke sends a signal to the control assembly 195 which is an indication of the start of smoking (ie that there is a constant drop in pressure or air flow for a sufficiently long period of time). Logic circuit 195 includes elements for distinguishing between minor changes in air pressure and a stronger draw of smoke on the cigarette, to avoid inadvertent activation of the heating elements in response to a signal from the draw-activated sensor 45. The sensor 45 may include a piezoresistive pressure sensor or an optical wafer sensor which is used to drive the operational amplifier, the output of which is used to send a logic signal to the logic circuit 195. Smoke-responsive sensors suitable for smoking device applications include a silicon sensor model 163PC01D35 manufactured by the MicroSwitch division ) by Honeyvell, Inc., Freeport, 111., or type NPH-5-02.5G NOVA sensor by Lucas-Nova, Freemont, California, or type SLP004D sensor by SenSym Incorporated, Sunnyvale, California.

The light sensor 53 for detecting the insertion of a cigarette sends a signal to the logic circuit 195 which is an indication that the cigarette 23 is inserted into the lighter 25 to the proper depth (ie, the cigarette 23 is located at a distance of several millimeters away from the light sensor mounted by means of the spacer element 49 and the base 50 of the heater assembly 39, which is established by the reflected beam of light). A light sensor suitable for use with a smoking device is the OPR5005 Light Sensor, manufactured by OPTEK Technology, Inc., 1215 West Crosby Road, Carrollton, Texas 75006.

In order to conserve power, it is recommended that the retracting sensor 45 as well as the light sensor 53 be cycled on and off with shorter duty cycles (eg, from approximately 2 to 10% of a full duty cycle). For example, it is recommended that smoke-responsive sensor 45 be turned on for 1 millisecond every 10 milliseconds. If, for example, the pull-in sensor 45 detects a drop in pressure or air flow, as an indication of cigarette smoke being drawn in, during four consecutive pulses (ie, during a 40-millisecond period), the pull-in sensor sends a signal via terminal 221 to logic circuit 195. Logic circuit 195 then sends a signal through one of the respective terminals 211-218 to turn on one of the respective heater FET switches 201-208 to the ON position.

Similarly, the light sensor 53 preferably turns on for 1 millisecond every 10 milliseconds. If, for example, the light sensor 53 detects four consecutive reflected pulses, as an indication of the presence of a cigarette 23 in the lighter 25, the light sensor sends a signal via terminal 223 to the logic circuit 195. The logic circuit 195 then sends a signal via terminal 225 to the sensor 45 which is activated by retraction and turns on him. The logic circuit also sends a signal via pin 227 to indicator 51 to turn on. The above modulation techniques reduce the time averaging current required for pull-in sensor 45 and light sensor 53, thereby extending the life of power source 37.

Timer 197 is preferably a constant Joules energy timer and is used to provide a closing signal to logic circuit 195 at terminal 229, after one of the heating elements, which has been activated by turning on (ON) one of the heater FET switches 201-208, was included during the desired time period. In accordance with the present invention, timing circuit 197 provides a shutdown signal to logic circuit 195 after a period of time measured as a function of the power source voltage, which decreases during heating of the heating elements. The timing circuit 197 is also adapted to prevent activation of the heating element 43 after the battery is discharged. Other timing configurations can be used, such as those described below.

During operation, the cigarette 23 is inserted into the lighter 25, and the presence of the cigarette is detected by the light sensor 53.

Light sensor 53 sends a signal to logic circuit 195 via port 223. Logic circuit 195 checks whether power source 37 is charged or low voltage. If, after inserting the cigarette 23 into the lighter 25, the logic circuit 195 determines that the voltage of the power source 37 is low, the indicator 51 begins to flash and further operation of the lighter is stopped until the power source is recharged or replaced. The voltage of the energy source 37 is also monitored during the ignition of the heating elements 43, and the ignition of the heating elements is interrupted if the voltage falls below a predetermined value.

If the power source 37 is charged and there is sufficient voltage, the logic circuit 195 sends a signal via terminal 225 to the draw-in sensor 45 to determine whether the smoker is inhaling the smoke on the cigarette 23. At the same time, the logic circuit 195 sends a signal via terminal 227 to the indicator 51 so that the liquid crystal display (LCD) displays the number "8", indicating that there are eight more smoke draws available.

When the logic circuit 195 receives a signal via port 221 from the pull-in sensor 45 that a certain pressure drop or airflow has been detected, the logic circuit turns off the light sensor 53 during the pull-in to save power. Logic circuit 195 sends a signal via port 231 to timing circuit 197 to activate the constant Joules energy timing circuit. Logic circuit 195 also determines, by counting down, which of the eight heating elements is next to fire and sends a signal through one of the corresponding terminals 211-218 to turn one of the corresponding heater FET switches 201-208 ON. The corresponding heater remains on as long as the timing circuit is operating.

When the timing circuit 197 sends a signal through the connection 229 to the logic circuit 195 that the timing programmer has stopped working, a certain FET switch of the heater 211-218, which was turned on and in the ON position, is turned off, that is, switched to the OFF position, thereby cutting off the supply of energy to the heater element. The logic circuit 195 simultaneously counts down and sends a signal to the indicator 51 via port 227 so that the on-screen indicator shows that there is one less draw of smoke left (ie, "7" after the first draw). When the smoker next takes a puff on the cigarette 23, the logic circuit 195 will turn on (ON) the next predetermined heater FET switch 211-218, thereby allowing power to be delivered to another predetermined heating element. The procedure will be repeated until the indicator 51 shows "0" on the screen, which means that there is no smoke left on the cigarette 23. When the cigarette 23 is removed from the lighter 25, the light sensor 53 determines that there is no cigarette and the logic circuit 195 is set to the initial state.

The control circuit 41 may have other properties, such as those described below, instead of or in addition to the properties described so far. For example, if desired, different blocks can be performed. One type of interlock allows a timing circuit (not shown) to prevent successive fumes from being drawn too closely spaced, so as to allow the energy source 37 to be renewed. ) product. For example, the cigarette 23 may be equipped with some distinguishing characteristic that the lighter 25 must recognize before lighting the heating elements 43.

Figure 19 shows another embodiment of a smoking device 222 in accordance with the present invention. The smoking device 222 has a disposable cigarette 224 and a reusable lighter 226 having a throat 228 into which the cigarette is placed. The smoking device 222 is a "central draw" system in which the airflow is mainly through the central portion of the cigarette 224 and the lighter. The igniter 226 includes a power source (not shown) at an end remote from the nozzle 228 and control assembly (not shown). Like the smoking device 21, the smoking device 222 is preferably made with elements such as a smoke-activated sensor and an indicator (not shown).

The lighter 226 is covered by a housing 232 which gives an appearance similar to a conventional cigarette. The housing 232 is preferably tubular, and may be made of heat-resistant plastic or aluminum, or of spirally wound, double-layer heavy paper. The housing is provided with a perforation 233 to allow outside air to be drawn into the lighter 226 during smoking. If desired, air passages (not shown) may be provided in the cigarette 224 or at other locations along the lighter 226 in order to achieved the desired air flow.

Cigarette 224 is similar to cigarette 23. Cigarette 224 has a tobacco paper 257 derived from a support or plenum 259 that carries (holds) tobacco flavoring material 261, which preferably includes tobacco. Tobacco paper 257 is wrapped around and supported by a cylindrical return filter 263 on one side and a cylindrical free-pass first filter 265 on the opposite side. The first free-pass filter may have a longitudinal pass (not shown).

The cigarette 224 also includes a cylindrical filter pen 271 , which should preferably be a conventional resistance-to-draw (RTD) type filter. The cigarette 224 may have a cylindrical second free-pass filter (not shown) that facilitates mixing of the vapor phase of flavored tobacco smoke and air, similar to the second free-pass filter 73 described above. The return filter 263 and the first free-pass filter 265 form, together with the tobacco paper 257, a cavity 279 within the cigarette 224. The first free-pass filter 265, the return filter 263 and the filter whistle 271 are preferably secured together by a process compatible with conventional machines. large mounting capacity.

Unlike the cigarette 23, the cigarette 224 has an annular protective tube 273 as an aerosol protection, placed around and at a predetermined distance from the tobacco paper 257. This protective anti-aerosol tube 273 minimizes the condensation of the aerosol created by heating the tobacco flavoring material 261 on the inner housing walls 232. The aerosol protection tube 273 is preferably secured to the cigarette 224 around the first free-pass filter 263 by means of a ring 275. The ring 275 and the aerosol protection tube 273 are sufficiently rigid to prevent crushing of the cigarette 224 and to retain the parallelism of the protective tube and the outer surface of the tobacco paper 257, so that a substantially uniform gap is maintained between the inside of the aerosol protection tube and the paper. A wrapping or filter paper 269 secures the filter nozzle 271 in position immediately next to the first free passage filter 265, the hoop 275 and one end of the aerosol protection tube 275.

Lighter 226 includes a heater assembly 239 having multiple, preferably eight, heating elements 243 for heating cigarette 224. Heating elements 243 are generally linear in shape and extend from a location within lighter 226 near throat 228 to a point near return filter cavity 245 which is adapted to accommodate the return filter. The heating elements 243 are joined together at one end, preferably at the end near the return filter cavity 245, and are beveled at one end near the throat 228 to facilitate insertion of the cigarette 224 without damaging the heating elements. The heating elements 243 are placed in the gap between the tobacco paper 257 and the tube 273 for protection against aerosols.

Figure 20 shows a schematic representation of the heater assembly 239. The heater assembly 239 includes a heater base 249, a heater support 251, and multiple heater support arms 253, all made of thermally stable, electrically insulating material. Heaters 243 are mounted on support arms 253. Heaters 243 are electrically connected at opposite ends 243' and 243'' by conductive extensions (fingers) 255A and 255B.

The ends 243' of the heater 243 are all electrically connected together to form a "common terminal" of the heating system. The common connection 291 is connected to the conductive plate 293 which is further connected to the common conductive extensions 255A, which in turn are electrically connected to the ends 243' of the heater 243. The plate 293 includes one or more air passages 295 which allow air to flow into the zone immediately to the return filter 263 of the cigarette 224 during the inhalation of smoke on the cigarette.

A grommet 299 is threaded onto the heater ring 297 around the common connection portion 291 adjacent to the conductor plate 293. The grommet 299 has one or more passages 301 for passing air current into the passages 295. Conductive pins 303 extend through the ring portion of the heater 297 to make an electrical connection between the conductive extensions 255B and control assembly 241. Conductive extensions 255B extend along the outer edges of heater support arms 253 and are individually electrically connected to ends 243'' of heating elements 243.

The ends 255B' of the conductive extensions 255B are preferably bent to facilitate the formation of a "snap-fit" connection between the heater ring 297 and the neck 299, in which the ends 255B' are in contact with the pins 303. The snap-fit connection allows the heating elements 243 to be removed from lighter 226 for replacement or repair. Pins 303 and common connector 291 enter corresponding sockets (not shown) for the purpose of connecting the heating elements 243 to the control assembly 241 for individual ignition of the heating elements.

Figure 22 shows schematically one version of the device 321 for the production of the part 224' of the cigarette 224, which contains tobacco paper 257, the first free-pass filter 265 and the return filter 263. The carrier material 259' for making the carrier 259 is pulled from a roll of material 323 using measuring rollers (not shown).

The weft of carrier material 259' shown in this embodiment includes spaced zones of tobacco flavored material 261 which are applied to the base carrier material 259' at station 325, or at any position prior to winding the roll 323. The carrier material 259' then passes through an application device. adhesive, which includes an adhesive application station 327 in which a plurality of adhesive zones 261A are applied to the surface of the carrier material 259'. Alternatively, the tobacco-flavored material 261 may be applied continuously along the entire length of the carrier material 259', and at predetermined locations, the adhesive zones 261A may be applied over the tobacco-flavored material.

Behind the adhesive zone application station 327 is a filter application station 329. This filter application station 329 preferably has a rotary drum device 331 for alternately applying the filter 333 or the filter 335 to the adhesive zones 261A located on the carrier material 259'. The rotational speed of the device 331 is synchronized with the speed of the carrier belt 259'.

Behind the filter placement station 329, there is a wrapping station 337. The carrier material 259' is wrapped around the filters 333 and 335 to form a continuous rod. After the rod is shaped, it is cut in the cutting station 339. The cutting station includes a device for cutting the rod in the middle of the filters 333 and 335, so that the cut parts of the filter 333 form two first free-pass filters 265 265, and the cut parts of the filter 335 form two return filters 263 from two parts 224' to form a cigarette 224. If desired, return filters 263 are machined after cutting to have an angled end to facilitate insertion of heating elements 243 around parts 224'. After cutting, each part 224' is placed in an aerosol protection tube 273 in a protection tube installation station (not shown), and secured therein by means of a ring 275. The protection tube 273 has a diameter greater than the diameter of the continuous rod and has a length of at least as individual cut cigarettes 224. A generally cylindrical filter pen 271 is placed over each free passage filter 265, and each aerosol protection tube 273 and its corresponding filter pen 271 are wrapped with wrapping paper in additional cells (not shown).

The following embodiment of the smoking device 421 is shown schematically in Figure 23. The smoking device 421 is designed to achieve a "peripheral draw-in" smoking system in which the heating elements 443 of the lighter 425 are arranged inside the cavity 427, connected by one ring part of the cigarette 423 .

The cigarette 423 includes a tobacco paper 457 having a tobacco flavoring material 461 applied to the surface of the carrier 459 opposite the cavity 427. The cigarette 423 further comprises an aerosol protection tube 473, a plug 475, an annular free-pass filter 465, an annular return filter 463 and the filter whistle 471. The free-pass filter 465, the return filter 463, the tobacco paper 457, and the aerosol protection tube 473 define a cavity 479 in which the tobacco-flavored smoke is developed after the tobacco-flavored material 461 is heated by the heater 443. The cigarette 423 is preferably wrapped with wrapping paper or filter paper 469. The heater assembly 439 is equipped with a plug 477 which, together with the plug 475, serves to minimize aerosol transmission through the heater zones of the smoking device 421. The plug 477 is made with holes for the passage of the conductor 481 for the control of the heating elements 443.

Figure 24 shows a schematic diagram of the alternative electrical control system 541. The control system 541 should fulfill several functions. It preferably sequentially selects from (typically) eight heating elements 43 to select the next available heating element 43 each time smoke-activated sensor 45 is activated. It supplies current to the selected heater for a predetermined duration and long enough to produce enough flavored tobacco smoke for one average draw, but not so long as to cause combustion of the tobacco flavoring material 61. This system preferably operates indicator 51 which indicates : (1) how many cigarettes 23 are left (ie, how many puffs of smoke); (2) whether the voltage of the power source 37 is out of range (inappropriate); (3) whether the cigarette is inserted into the lighter 25 or not; and (4) whether the heater assembly is inserted into the lighter, such as the heater assembly 239 which is adapted to be inserted into the lighter 226 by means of a snap connection.

The control system 541 also controls the total amount of power that the power source 37 delivers to each heating element 43. Since the voltage provided by the power source 37 can vary from one draw to the next, instead of providing a variable amount of power and energy by activating each heating element 43 in the same time duration, it is recommended to deliver a constant amount of energy for each pull. To achieve constant power delivery, the controller 541 monitors the load voltage of the power source 37 while the heating element is on and continues to supply current to the heating element until the desired amount of energy in Joules is delivered.

As seen in Figure 24, the control system 541 includes a logic circuit 570, a BCD also 580, a voltage detector 590, a timing circuit 591, a feed-activated sensor 45, an indicator 51, and a charger circuit 593. The logic circuit 570 may be any conventional a circuit capable of containing the functions specified herein, such as a field-programmable logic circuit (eg, type ACTEL A1010A FPGA PL44C, manufactured by Actel Corporation of Sunnyvale, California) that is programmed to perform such functions. Preferably, logic circuit 570 operates with low rate cycles (eg 33kHz) to conserve power. Each heating element 43A-43H is connected to the positive terminal of the power source 37 and to ground via a corresponding field effect transistor (FET) 595A-595H.

Certain FETs 595A-595H are turned on by command of a BCD decoder 580 (BCD-binary coded decimal, eg) (preferably a standard type CD4514B 4 to 16 line decoder) via terminals 581-588. BCD decoder 580 receives two types of signals via control port 580A from logic circuit 570: (1) BCD code of the individual heater 43A-43H to be turned on; and (2) ON and OFF signals for that heater.

BCD decoder 580 is connected, via terminal 580B, to terminal 593A of charging circuit 593 which provides a voltage used to drive the gate of each field effect transistor (FET) 595A-595H. The charger assembly 593 includes a diode 594 connected to the power source 37 and a capacitor 595 connected to the logic circuit 570. The logic circuit 570 includes a conventional switching network (not separately shown) connected to a terminal 572 which allows the voltage at the terminal 593A of the charger assembly 593 to be increased to, preferably, approximately twice the value of the voltage of the power source 37. Diode 594 prevents such a voltage from being reconnected to the power source 37. Thus, double the voltage at terminal 580B of the decoder 580 is used to drive the gates of the field effect transistor (FET). 595A-595H at increased voltages, to increase the efficiency (utilization rate) of the control circuit 541. Resistors 596A-596H are connected in series with the control electrodes of the field effect transistor (FET) 595A-595H, and are included to increase the charging time of the respective control electrodes to reduce the generation of high harmonic frequency that could create noise in the 541 control system.

Sensor 45, which is activated by smoke inhalation, sends a signal to logic assembly 570, which signal is indicative of smoker activation (ie, a continuous pressure drop of approximately 2.54 cmVS).

Thus, smoke actuated sensors 45 may have a piezoresistive pressure sensor used to drive an operational amplifier, the output of which is then used to send a logic signal to logic circuit 570. For example, the pressure sensor may be a type NPH-5- 002.5G NOVA, manufactured by LucusNova, Freemont, California, or type SLP004D sensor, manufactured by Sensym Incorporated, of Sunnyvale, California.

To conserve power, it is recommended that the pull-in sensor 45 be cycled on and off with shorter duty cycles (eg, approximately 2% to 10% of full duty cycle). For example, it is recommended that sensor 45 be turned on for only 0.5 ms every 16 ms. This modulation technique reduces the time average current required for the pull-in activated sensor 45, thereby extending the life of the power source 37.

Timer circuit 591 is used to provide a shutdown signal to logic circuit 570 after one of the heaters 43A-43H has been on for a predetermined period of time, depending on the amount of power supplied to the heater. In accordance with the present invention, it is recommended that each heater 43A-43H be activated for such a period of time that a constant amount of energy is delivered to each heater (eg in the range of 5 to 40 Joules or, even better, between 15 to 25 Joules), independent of the load voltage of the energy source 37. Therefore, the connection 591A gives the timing circuit 591 information about the duration of each heater 43 and the operating voltage of the energy source 37, assuming that the heat resistance is known and constant (i.e. 1.2 .Ω ). Terminal 591B then sends a shutdown signal to logic circuit 570 via terminal 578 as an indication of the time period corresponding to the delivery of a constant amount of power.

Figure 24 shows the recommended design of the timing circuit 591. The timing circuit 591 has a terminal 591A that receives a signal from the logic circuit 570 that changes from approximately zero volts to the battery workload voltage level at the time each heater 43A-43H starts to activate. This signal is filtered through a resistor-capacitor circuit 601 (including resistors 603-606, capacitor 607 and diode 608) and is used to drive an overvoltage detector 602. The overvoltage detector 602 is preferably an over/undervoltage detector type ICL7665A available from the manufacturer. Maxim Corporation, of Sunnyvale, California. In accordance with the present invention, the resistor-capacitor circuit 601 is selected so that the terminal 591B of the timing circuit 591 switches from a higher level (HIGH) to a lower level (LOW) at the moment when a predetermined constant amount of energy is supplied to each heater. Other timing configurations can of course be used. If desired, the controller 541 sets a limit on the longest duration of the time period for delivering a constant amount of energy. For example, if the voltage of the power source 37 is so low that it would take more than 2 seconds to deliver 20 Joules of energy, then the logic circuit 570 provides an automatic shutdown signal via terminal 571 after the heater has been on for 2 seconds, even though 20 Joules - and it had not been delivered yet.

In an alternative embodiment of the present invention, timing circuit 591 is used to provide a closing signal to logic circuit 570 for a predetermined period of time independent of the power delivered. Thus, the timing circuit 591 gives a signal to close after, for example, a precisely determined time period in the range of 0.5 seconds to 5 seconds. The voltage detector 590 is used to monitor the voltage of the power source 37 and to provide a signal to the logic circuit 170 when the voltage is either (1) lower than a first determined voltage (eg, 3.2 volts) which is an indication to recharge the power source, or (2 ) higher than the second predetermined voltage (eg 5.5 volts), which is an indication that the energy source is fully charged after the voltage has fallen below the first, previously determined level.

The voltage detector 590 should preferably be an over/under voltage detector type ICL7665A available from Maxim Corporation, Sunnyvale, California.

As previously explained, logic circuit 570 is used to control BCD decoder 580 via port 571. Logic circuit 570 also controls indicator 51 which is used to indicate the number of smoke draws remaining available to the user and which is a single digit, seven segment display with liquid crystals (LCD) for smoking device with eight intakes. Thus, for a newly inserted cigarette that has eight corresponding pieces of tobacco flavoring material, the indicator 51 shows the number "8", while for a cigarette with only one puff remaining, the indicator 51 shows "1". After drawing in the last smoke, the indicator 51 shows "0".

In addition, the indicator 51 shows "0" also in the case when there is no cigarette or heater assembly or heater (eg, the heating elements 243 with a snap-on fit are not placed in the heater assembly 239) in the lighter. Furthermore, to indicate that the voltage of the power source is out of the specified range, i.e. that it has fallen below the recharge level (eg 3.2 volts) or is not fully charged after the voltage has fallen below the recharge level, the indicator 51 turns on and off repeatedly with a frequency of 0.5Hz. For example, if the voltage of the power source drops below 3.2 V immediately after the first pull-in, the indicator 51 flashes and shows the number "7" twice per second.

The logic circuit 570 determines, through the connections 597A and 598A, whether the heater assembly or the heater is placed in the lighter by measuring the corresponding voltage drops on the high resistance resistors 597 and 598 (eg 1 M). Each of the resistors 597 and 598 has one terminal permanently connected to the drains of the field effect transistors (FET) 595G or 595H, and the other connection is connected to the ground. When the heater assembly is not placed in the lighter, the heaters marked with reference numbers 43G and 43H in Figure 23 are disconnected from the drain (FET) of transistor 595G and 595H. Therefore, the power source 37 is also disconnected from the drains (FETs) of transistors 595G and 595H. The consequence of this is that no voltage is generated on the arrestors 597 and 598, which is monitored by the logic circuit 570 via the connections 597A or 598A. Therefore, when the heater assembly is not installed in the igniter, logic circuit 570 detects two "zeros" at terminals 597A and 598A.

While the heater assembly is inserted into the electric igniter, the power source 37 is connected to resistors 597 and 598 via heater 43G and respectively. 43H. This results in a voltage across resistors 597 and 598, causing logic circuit 570 to normally detect two "ones" across terminals 597A and 598A. Logic circuit 570 monitors two resistors (ie, resistors 597 and 598) because if either transistor (FET) 595G and 595H turns on to activate its associated heater, the corresponding resistor 597 or 598 becomes effectively grounded. This can result in, even when the heater assembly is in place, giving a false indication that the assembly is not present due to the use of only one resistor.

In any case, if two resistors are used, then, for example, while FET 595G is on, the voltage across resistor 597 is close to zero, and the voltage across resistor 598 is an indication of a logic "one", while FET 595H is on , then the voltage across resistor 598 is close to zero and the voltage across resistor 597 is an indication of a logic "one". Therefore, two resistors 597, 598 are used, and the associated signals from resistors 597 and 598 are logical OR read in logic circuit 570 to determine if the heater assembly is installed in the electric igniter.

In order to be able to determine if a cigarette is inserted into the lighter, logic circuit 570 has one additional port 599 that receives a signal each time a cigarette is physically present in the lighter. The signal at port 599 is produced by a conventional switch 599A, which is mechanically and electrically activated by the presence of a cigarette. However, if the cigarette has a carbon fiber mesh according to the subject invention as previously explained, it is recommended that the signal at port 599 be produced by connecting an electrical probe directly to the carbon mesh to monitor the electrical currents passing through the mesh. Since the carbon grid is not perfectly insulating, if a heater, one terminal of which is connected to the power source 37 as in Figure 23, is brought into contact with the carbon grid according to the present invention, some electric current is passed through the carbon grid regardless of whether the transistors (FET) 595A-595H activated or not. In accordance with the present invention, such a passed current is monitored by an electric sensor connected directly to the carbon grid in order to detect the presence of a cigarette.

In addition to the use of electrical conductivity through the carbon mesh to determine whether a cigarette has been inserted into an electric lighter, such conductivity can also be used, if desired, to determine the presence of certain types of cigarettes (eg, cigarette type X, versus cigarette Y). In accordance with the above characteristic of the present invention, the logic circuit 570 is used to determine the specific resistance of the carbon network by incorporating two additional terminals (not shown) which are in contact with the carbon network with a certain mutual distance. By producing a special type of carbon mesh so that it has a pre-selected specific resistance within a selected range (ie by changing the type and amount of carbon fibers and/or binders in them), which resistance is exclusively suited to a particular type of cigarette, the specific resistance measurement can be used to distinguish between different types of cigarettes that are inserted into the electric lighter. This information is then used in logic circuit 570 to enable delivery of the preselected amount of electricity. For example, a first type or brand of cigarette is manufactured with a carbon mesh having a first predetermined specific resistance, while a second type or brand of cigarette is manufactured with a second but different predetermined specific resistance.

Thus, if the logic circuit 570 can determine the specific resistance associated with the inserted cigarette, in situ, then such measurement is used to actively control the delivery of electrical power to the lighter heaters.

In accordance with the above-mentioned characteristic of the subject invention, the conditions for the delivery of electricity then change depending on the particular type or type of cigarette that is in the lighter. For example, once the logic circuit 570 has established the specific resistance corresponding to a particular cigarette, it will, due to its performance, deliver either 15 Joules or 20 Joules of energy, depending on the measured specific resistance. Further, logic circuit 570 also has circuitry to prevent delivery of any amount of power if it is determined that the specific resistance corresponding to a particular cigarette is not compatible with the particular lighter into which that cigarette is inserted.

According to Figure 23, before the smoker draws the first smoke, the indicator 51 shows, for example, the number "8" indicating that there are eight more puffs available. Accordingly, logic circuit 570 provides the address (label) of the first heater (eg, heater 43A) to port 571, so that BCD decoder 580 selects that heater (eg, via port 581) to fire upon activation of the smoker. When the smoker takes a puff, smoke-triggered sensor 45 sends a HIGH signal via port 575 to logic circuit 570, indicating that the pressure in the lighter has dropped, e.g. for at least 1 inch (2.54 cm) of water. At that point, logic circuit 570 sends a signal via terminal 571 indicating to BCD decoder 580 that transistor (FET) 595A for the first heater should be turned ON (turned ON). Thereafter, the voltage at terminal 580B of the BCD decoder 580 is coupled through the BCD decoder 580 to the drain of the first transistor (FET) 595A to set the heater to the ON position.

Simultaneously with the start of activation of the first heater 43A, the timing circuit 591 monitors the current total amount of energy that was delivered to the heater, and gives a logic signal to the logic circuit 570, via the connection 578, at the moment when the quantity reaches a predetermined value (e.g. 20 Joules ). Logic circuit 570 then sends an OFF signal via port 571 to BCD decoder 580 which, in response, causes heater 43A to turn off.

After that, while waiting for the smoker to inhale the second smoke, the logic circuit 570 sends the address of the second heater (eg 43B) to the BCD decoder 580, via port 571, so that during the next smoke inhalation, the second transistor (FET) 595B is activated. Likewise, the logic circuit 570 sends a signal to the indicator 51 to display the number "7" on the screen, thereby indicating to the smoker that there are seven puffs remaining.

Optionally, the logic circuit 570 may also include a timing control circuit to prevent the smoker from inhaling the next smoke within a predetermined period of time to allow the power source to be regenerated. For example, the logic circuit 570 may have a circuit (not shown separately) that prevents an ON signal from being sent to the BCD decoder 580 via terminal 571 for a 6-second OFF period after the last OFF signal was sent. to BCD decoder 580. If desired, to indicate to the smoker that the lighter is in the off state, the indicator 51 is repeatedly turned on and off at a frequency of, for example, 4 Hz (ie, at a rate different from the rate used to indicate to the smoker that the power source voltage outside the operating range).

Regardless of whether or not the lighter includes the above smoke inhibit feature or an indication of such disablement, when the smoker draws a second smoke (after a predetermined time in which logic signals are prevented from being sent, if that feature is implemented), the control circuit 541 repeats above steps used to activate the first heater.

The above cycle is then repeated until the last heater has been heated. At that point, logic circuit 570

(1) sends a signal to the indicator 51 that the screen should be blank and

(2) prevents further activation of any heater until a new disposable cigarette is inserted into the lighter.

Although the control system 541 of FIG. 23 shows the logic circuit 570, BCD decoder 580, voltage detector 590, and timing circuit 591 as separate circuits, it is apparent that their functions may also be unified into a single integrated system (eg, a chip with one integrated assembly).

The disposable cigarette according to the present invention includes, if desired, elements for indicating to the smoker that the cigarette has already been previously placed in the lighter and then removed. For example, in one embodiment, an unused cigarette has a strip or other element that must be removed from the cigarette before inserting the cigarette into the lighter. Because of this, a cigarette that has already been used before does not have a suitable release strip or similar element. Alternatively, an unused cigarette has a zone on it that, after inserting the cigarette into the lighter, changes its physical characteristics and becomes torn, destroyed, compressed or otherwise physically changed. In this way, the smoker can determine whether that cigarette has already been placed in the lighter by visual inspection of the zone that changes its physical characteristics. In addition, the disposable cigarette may, if desired, have means for indicating to the smoker that a particular cigarette has already been heated to create and deliver tobacco-flavored smoke.

For example, a cigarette may have a heat-sensitive zone, which changes color as an indication to the smoker that the cigarette has already been heated. Alternatively, the heat-sensitive zone may include a strip that melts, opens circuits, or otherwise physically changes shape to indicate to the smoker that the cigarette has already been heated. Of course, there are various other means that are heat activated to indicate that the cigarette has already been heated. In addition, it is apparent that many other electrically or mechanically actuated means can be used to achieve the same goal -- ie. indicated to the smoker that the cigarette had already been heated.

While the present invention has been illustrated and described in accordance with a preferred embodiment, it is understood that variations and changes may be made within that embodiment without departing from the present invention as further set forth in the claims.

Claims (162)

1. A cigarette for use in a smoking device for creating and supplying the smoker with flavored tobacco smoke, where the device includes at least one electrical means for heating, and the cigarette consists of: a supporting element (support) that has the first and second ends spaced from each other and in the longitudinal direction, and having a first and a second surface, wherein the first surface defines a cavity between the first and second ends, and the second surface includes a zone that is placed immediately next to the electric heater; and a tobacco-flavored material disposed on a first surface of the support, which tobacco-flavored material produces tobacco-flavored smoke in the cavity for delivery to the smoker when the tobacco-flavored material is heated by an electric heater, characterized in that the support and the tobacco-flavored material allow cross-flow of air in the cavity. 2. A smoking device for supplying flavored tobacco smoke to a smoker, which device consists of: a cigarette that can be removed, where the cigarette includes a support having first and second ends spaced from each other in the longitudinal direction and having first and second surfaces, wherein the first surface defines a cavity between the first and second ends, and the tobacco-flavored material for producing tobacco-flavored smoke in the cavity, wherein the tobacco-flavored material is disposed on the first surface of the carrier; a lighter, wherein the lighter includes a heater assembly for receiving, through the first end, a replaceable cigarette, and a plurality of electric heating elements arranged in the heater assembly, wherein each of the heating elements has a surface that is placed immediately adjacent to another surface of the cigarette and which heating the elements heat the tobacco-flavored material to produce tobacco-flavored smoke in the cavity; and a system for individually activating the heating elements so that a previously determined amount of tobacco-flavored smoke is created in the cavity, indicated by the fact that the carrier and the tobacco-flavored material enable cross-flow of air into the cavity. 3. The cigarette of claim 1 or 2, characterized in that the carrier is in the form of a mostly hollow cylinder, wherein the first surface forms the inner surface, and the second surface forms the outer surface. 4. The cigarette from patent claims 1, 2 or 3, which further contains: a filter with a free passage placed to the other end of the support, where this filter with a free passage represents the structural support of the cigarette and enables the longitudinal flow of air from the cavity; and a return filter positioned to the first end of the carrier, where the return filter secures the cigarette and restricts the longitudinal flow of air through the cigarette. 5. The cigarette of claim 4, characterized in that the first free-pass filter and the return filter are generally cylindrical and each has a surface defining a portion of the cavity. 6. The cigarette of claim 4, which additionally has a filter nozzle. 7. The cigarette of claim 6, which further has filter paper wrapped around the filter mouth and at least one part of the support for attaching the filter mouth to the support. 8. The cigarette of claim 4, which further contains a second filter with a free passage immediately next to the first filter with a free passage, characterized in that both the first filter with a free passage and the second filter with a free passage are made with longitudinal passages, wherein the longitudinal passage of the second of the free-pass filter has a larger inner diameter than the longitudinal passage of the first free-pass filter. 9. The cigarette of any one of claims 1 to 8, further comprising a wrapping paper wrapped around the carrier. 10. Cigarette from any one of patent claims 1 to 9, characterized in that the carrier is composed of a non-woven network (weft) of carbon fibers. 11. A cigarette according to any one of claims 1 to 10, characterized in that the tobacco-flavored material contains tobacco material. 12. Cigarette according to any one of patent claims 1 to 11, characterized in that the tobacco-flavored material consists of a continuous sheet (plate) of tobacco material. 13. A cigarette according to any one of claims 1 to 11, characterized in that the tobacco-flavored material contains a dried suspension of tobacco material. 14. Cigarette from any one of patent claims 1 to 15, characterized by the fact that in the carrier and material with tobacco aroma, a greater number of perforations are made that allow transverse air flow during smoking. 15. Cigarette from any one of patent claims 1 to 14, characterized in that the permeability of the support and material with tobacco aroma is previously determined and that it allows transverse air flow. 16. A lighter for use in conjunction with a replaceable cigarette in a smoking device that generates and delivers tobacco-flavored smoke to a smoker, the lighter comprising: a heater assembly for receiving, through a first end, a replaceable cigarette, the heater assembly has means for enabling air flow to at least one part of the cigarette; and a larger number of electric heating elements arranged in the heater assembly, where each heating element has a surface that is placed right next to the surface of the part of the cigarette to which air can flow; and a system for individually activating a number of heating elements so that a previously determined amount of smoke with a tobacco aroma is produced in the cigarette, indicated by the fact that, when the smoker draws smoke on the cigarette inserted in the lighter, the air flows transversely into the cigarette. 17. The lighter of claim 2 or 6, characterized in that the heater assembly has a cover at the first end, the cover having one open end for accepting a cigarette. 18. The lighter from patent claim 17, characterized in that the cover ensures a close fit of the cigarette. 19. Lighter according to patent claim 17 or 18, characterized in that the means for enabling air flow include one or more air passages made in the cover. 20. The lighter from patent claim 19, characterized in that one or more air passages are made in the form of a hole through the cover. 21. The lighter from patent claim 19, characterized in that one or more air passages are designed as grooves on the inner wall of the cover, and that these grooves are connected to the cigarette after placing the cigarette in the lighter. 22. Lighter according to claim 17, 18, 19 or 20, characterized in that the heater assembly has a mostly cylindrical wall which, with the cover, defines the space into which at least part of the cigarette enters. 23. The lighter from patent claim 22, characterized in that the means for enabling the flow of air include one or more air passages made in the cover that allow the flow of air into the space. 24. The lighter from claim 2 or 16 characterized in that the heater assembly has a mostly cylindrical wall that defines the space into which at least part of the cigarette enters. 25. The lighter from claim 24, characterized in that, after inserting the cigarette into the lighter, the air is allowed to flow between the cylindrical wall and the cigarette. 26. The lighter according to claim 24 or 25, characterized in that the means for enabling the flow of air include one or more air passages made through a generally cylindrical wall. 27. The lighter according to patent claim 26, characterized in that one or more air passages are made immediately adjacent to the first end of the heater assembly. 28. The lighter of claim 26, characterized in that one or more air passages are provided near the other end of the heater assembly. 29. The lighter from patent claim 26, characterized in that a greater number of air passages are distributed along the cylindrical wall. 30. A heating element for use in a smoking device for creating and supplying tobacco-flavored smoke to a smoker, having: a first end and a second end, and a plurality of curved zones between the first and second ends to increase the electrical resistance of the heating element, wherein the heating element is made of resistant material which has a first and second surface mainly in the form of a flat surface, and which has a total length L, a total width W and a thickness T, indicated by the fact that the effective electrical length of the heating element is greater than the length L, and that the effective area of the transverse section of the heating element smaller than the product of W and T. 31. The heating element of claim 50, characterized in that the plurality of curved zones consists of a plurality of interconnected zones generally S-shaped. 32. The heating element of claim 31, which has N mutually S-shaped zones, characterized in that N is greater than three and less than twelve. 33. Heating element from claim 32, characterized in that N is greater than six and less than ten. 34. The heating element of any one of claims 30 to 33, characterized in that the heating element has a resistance in the range of approximately 0.8 Ω to approximately 2.1 Ω. 35. The heating element of any one of claims 30 to 34, characterized in that the resistant material consists of a material that exhibits surface stability at temperatures up to approximately 80% of its melting point. 36. The heating element of any one of claims 30 to 35, characterized in that the resistant material is a super alloy. 37. The heating element of claim 36, characterized in that the superalloy is based on at least one material selected from the group of materials including nickel, iron and cobalt. 38. Heating element according to any one of claims 30 to 35, characterized in that the resistant material is an intermetallic compound. 39. The heating element from claim 38, characterized in that the resistant material is an intermetallic compound resistant to oxidation, which is based on at least one material selected from the group of materials in which there are nickel aluminides and iron aluminides. 40. The heating element of claim 37, wherein the resistive material contains more than approximately 1% aluminum. 41. The heating element of any one of claims 30 to 40, characterized in that the first and second ends extend over (beyond) the plurality of curved zones, and that the first and second ends as well as the curved zones are made of a single piece of material. 42. The heating element of any one of claims 30 to 41, characterized in that the longitudinal central axes of the first and second ends and the plurality of curved zones are mutually aligned. 43. The heating element of any one of claims 30 to 42, characterized in that the transition surfaces between the first end and the plurality of curved zones as well as between the second end and the plurality of curved zones are beveled. 44. The heating element of any one of claims 30 to 43, characterized in that the end turns of the plurality of curved zones, which are located immediately next to the first and second ends, are turned in the same direction. 45. A process for the production of an integral heater for use in a smoking device to create and supply the smoker with tobacco-flavored smoke, which consists of the following steps: cutting a sheet of electro-resistant material to form a number of heating elements connected to each other at at least one end; and molding the plate into a cylindrical shape. 46. The method of patent claim 45, which further comprises a step in which the heating element is shaped in such a way that at least one part of the heating element is bent inward in the direction of the central axis of the cylindrical shape. 47. The method of claim 45 to 46, which further comprises a step in which the edges of the heating elements are flattened. 48. The method of claim 45, 46 or 47, characterized in that, during the straightening step, the heating elements are electro-polished. 49. The method of claim 45, 46, 47 or 48, characterized in that the plate is formed into a cylindrical shape after the plate is cut to form a plurality of heating elements. 50. The method of any one of claims 45 to 49, further comprising the step of welding together the edges of the connecting portion joining the plurality of heating elements. 51. The method from patent claim 50, characterized in that, in the welding step, the edges are laser welded. 52. The method from patent claim 51, characterized in that the laser is an yttrium-aluminum-garnet (YAG) laser. 53. The method according to any one of patent claims 45 to 52, characterized in that, in the cutting step, the sheet of electro-resistant material is cut using a laser. 54. The method of claim 53, characterized in that said laser is a CO2 laser. 55. The method of any one of claims 45 to 52, characterized in that, during the cutting step, the sheet of resist material is cut by means of precision cutting. 56. The method from patent claims 45 to 52, characterized in that, during the cutting step, the sheet of resistant material is cut by precise cutting. 57. The method from patent claims 45 to 52, characterized in that, during cutting, the sheet of electro-resistant material is cut by chemical grinding. 58. The method from claim 45 to 52, characterized in that, during cutting, the plate of resistant material is cut by chemical etching. 59. A cigarette comprising: a thermally permeable paper base formed into a generally cylindrical shape having an outer heat absorbing surface and an inner surface; and a tobacco-flavored material disposed on at least one portion of the inner surface, wherein said tobacco material releases flavored tobacco smoke when the outer surface of said base paper is heated. 60. The cigarette of claim 59, further comprising: wrapping paper wrapped around the outer surface. 61. A tobacco product adapted to work with a special heat source, wherein said tobacco product contains a weave of fibrous carbon and fibrous tobacco as well as flavored tobacco material distributed over the first surface of the weave, and a mesh of fibrous carbon that is adapted to receive heat in at least one place along the other surface and to transfer a significant part of that heat to the parts of the tobacco-flavored material that are closest to that place. 62. The tobacco product of claim 61, characterized in that the weave is in the form of a generally hollow cylinder having an internal cavity. 63. The tobacco product of patent claim 62, which further contains: a filter with a free passage directly next to the other end of the paper cylinder, which filter serves as a support for the paper cylinder and enables the longitudinal flow of air from the cavity; and a return filter immediately adjacent the first end of the paper cylinder, where the cylinder serves as a support for the paper cylinder and restricts the longitudinal flow of air from the cavity. 64. The tobacco product of claim 63, wherein the free-pass filter and the return filter are generally cylindrical and each has a surface defining a portion of the cavity. 65. The tobacco product of claim 63 or 64, further comprising a filter mouthpiece immediately adjacent to the free-pass filter. 66. The tobacco product of claim 65, further comprising a filter paper wrapped around the filter mouth and at least one portion of the paper cylinder to secure the filter mouth to the cylinder. 67. Tobacco product according to patent claim 63, 64, 65 or 66, which further has a second filter with a free passage immediately next to the first filter with a free passage, characterized by the fact that both the first and the second filter with a free passage are made with longitudinal passages, whereby the longitudinal passage of the second free-pass filter has a larger internal diameter than the longitudinal passage of the first free-pass filter. 68. The tobacco product of any one of claims 63 to 67, further comprising a wrapping paper wrapped around a paper cylinder. 69. Tobacco product from any one of the patent claims 63 to 68, characterized in that the paper cylinder has a large number of perforations that enable the desired cross flow of air during smoking. 70. Cigarette according to any one of patent claims 63 to 69, characterized in that the permeability of the paper cylinder is previously determined, and that it allows the desired cross flow of air. 71. A replaceable cigarette for use in a smoking device, which device includes a lighter, for creating and supplying flavored tobacco smoke to the smoker, wherein the lighter has electrical heating means arranged in a permanent cavity, and the replaceable cigarette consists of: a carrier having a first end and a second end as well as a first surface and a second surface, wherein the first surface defines a cavity for producing flavored tobacco smoke between the first and second ends, and the second surface is adapted to be placed directly adjacent to the electric heating means; tobacco flavored material distributed over the first surface, characterized in that, when the electrical heating means are activated, the corresponding portion of the tobacco flavored medium that is in thermal contact with the heating means is heated, which then creates a previously determined amount of flavored tobacco smoke for supply to the smoker; and filter elements for filtering a predetermined amount of smoke with tobacco aroma before releasing it to the smoker. 72. Replaceable cigarette according to patent claim 71, characterized in that the filter elements contain: a filter with a free passage immediately next to the other end of the support, adapted to be placed between the cavity in which the flavored smoke is created and the mouth of the smoker, in order to stiffen the cigarette; and a return filter immediately adjacent the first end of the carrier for filtering the return stream of tobacco smoke to reduce condensation of residual tobacco flavored smoke on any (a) heating element and (b) part of the fixed (permanent) lighter cavity. 73. Replaceable cigarette according to patent claim 72, characterized in that: the carrier forms a generally hollow cylinder with an inner and outer surface, wherein the electrical means for heating are placed directly next to the outer surface of the carrier; and that the tobacco-flavored medium is disposed on the inner surface of the cylindrical support, indicating that the tobacco-flavored smoke is generated within the support. 74. The replaceable cigarette of claim 73, wherein the free-pass filter and the return filter are generally cylindrical and each has a surface that forms a portion of the carrier cavity in which flavored smoke is generated. 75. The replaceable cigarette of claim 74, further comprising a generally cylindrical aerosol protection tube, which is concentric with the carrier and has a larger diameter than the carrier, characterized in that the inner surface of the protective tube and the outer surface of the carrier define the receiving (installation) zone. electric heating elements, whereby the protective tube reduces the condensation of smoke residues with tobacco aroma on parts of the permanent cavity of the lighter. 76. The replaceable cigarette of claim 75, characterized in that the generally cylindrical aerosol protection tube is attached to the free-pass filter by means of a ring of a material having a high drag resistance, the ring being determined by the size of the zone in which the heaters are placed. 77. The replaceable cigarette of claim 76, further comprising: a generally cylindrical filter spout immediately adjacent to the free-pass filter; and wrapping paper for wrapping the aerosol protection tube and for attaching the filter nozzle to the aerosol protection tube. 78. The replaceable cigarette from claim 76 to 77, characterized in that the carrier is composed of a non-woven carbon fiber network. 79. The replacement cigarette of claim 78, wherein the carbon fibers in the web have a basis weight in the range of between 6 g/m and approximately 12 g/m. 80. The replaceable cigarette of claim 79, characterized in that the tobacco-flavored material contains tobacco material. 81. The replaceable cigarette of claim 80, characterized in that the tobacco-flavored material consists of a continuous strip (sheet) of tobacco material. 82. The replaceable cigarette of claim 80, characterized in that the tobacco-flavored material consists of foamed tobacco material. 83. The replaceable cigarette of claim 80, characterized in that the tobacco-flavored material consists of a gel of tobacco material. 84. The replaceable cigarette of claim 80, characterized in that the tobacco-flavored material consists of a dried suspension of tobacco material. 85. The replaceable cigarette of claim 80, characterized in that the tobacco-flavored material consists of a spray-dried suspension of tobacco material. 86. A replaceable cigarette according to any one of claims 72 to 85, characterized in that: the carrier forms a generally hollow cylinder with an inner and outer surface, wherein the electric heating elements are distributed throughout the interior of the carrier; and the tobacco-flavored medium is disposed on the outer surface of the cylindrical support, wherein the tobacco-flavored smoke is generated outside the support. 87. The replaceable cigarette of claim 86, characterized in that the free-pass filter and the return filter are generally annular in shape and that each of them has a surface that forms part of the cavity in which the flavored smoke is generated. 88. The replaceable cigarette of claim 87, further comprising: a generally cylindrical aerosol shielding tube, a flavored tobacco smoke generation cavity, wherein the shielding tube reduces condensation of residual tobacco flavored smoke onto parts of the permanent lighter cavity. 89. The replaceable cigarette of claim 88, further comprising a generally cylindrical plug made of a material having a high resistance to drawing in and substantially filling the central portion of the free passage filter. 90. Replaceable cigarette from patent claim 89, which further contains; mostly cylindrical filter mouth directly adjacent to the free-pass filter; and wrapping paper for wrapping the aerosol protection tube and filter mouth, and for attaching the filter mouth to the aerosol protection tube. 91. A replaceable cigarette according to any one of claims 72 to 90, characterized in that the tobacco aroma medium consists of a spatially variable (different) tobacco aroma medium, and the release of the aroma to the smoker varies according to the choice of one puff of smoke to another. 92. The replaceable cigarette of claim 71, further including means for indicating to the smoker that the cigarette has previously been placed in the lighter and then removed. 93. The replaceable cigarette of claim 92, characterized in that the indicating means must be removed from the cigarette before inserting the cigarette into the lighter. 94. The replaceable cigarette of patent claim 92, characterized in that the indication means represent a zone on the cigarette that becomes physically changed after the cigarette is inserted into the lighter. 95. The replaceable cigarette of claim 71, further including means for indicating to the smoker that the cigarette has been previously heated. 96. The replaceable cigarette of claim 95, wherein the indicating means are thermally activated and change color to indicate that the cigarette has been previously heated. 97. Replaceable cigarette from patent claim 71, characterized in that the support is composed of a non-woven network of carbon fibers that has a previously selected specific resistance, and characterized in that the specific resistance corresponds to a specific type of cigarette so that it enables the control unit of the lighter to distinguish between different types of cigarettes. 98. A process for manufacturing a replaceable cigarette for use in a smoking device, wherein the smoking device includes a lighter, for creating and supplying a smoker with a tobacco flavor, wherein the lighter has electric heating elements placed in a fixed (permanent) cavity, which process includes : a) Procurement (preparation) of carrier paper that has zones of material with tobacco aroma; b) applying the adhesive zones to the support surface so that spaced zones with the adhesive are formed between the spaced zones of the tobacco flavoring material; c) placing the filter material on the adhesive zones on the surface of the paper carrier; d) wrapping the carrier around the filter to form a continuous rod with alternating zones of filter and tobacco flavoring material; and e) cutting the continuous rod in the filter zones to form individual replaceable cigarettes. 99. The method of patent claim 98, characterized in that the step of placing the filter material consists in placing a mostly cylindrical filter material. 100. The method from patent claim 99, characterized in that the step (phase) of placing the filter material consists in alternately placing a filter with free passage and a return filter on the adhesive zones in order to achieve the repetition of zones of filter material with free passage, material with tobacco aroma and return filter. 101. The method of claim 98, 99 or 100, wherein the step of cutting the continuous bar consists of cutting each zone of filter material substantially in half to form, alternately, a pair of return filters and a pair of free-pass filters. 102. The method of claim 101, further comprising machining the replaceable cigarettes to form a rounded end on the return insert filters. 103. The method of claim 101 or 102, further comprising placing a generally cylindrical aerosol protection tube on the free-pass filters, wherein the protection tube has a diameter greater than the diameter of the continuous rod and has a length at least equal to the length of the cut individual cigarette. 104. The method of claim 102 or 103, further comprising the step of placing (attaching) a generally cylindrical filter spout to each free-pass filter; wrapping each tube to protect against aerosols and the corresponding filter pipe with wrapping paper. 105. A replacement cigarette manufacturing device for use in a smoking device that produces and delivers tobacco-flavored smoke to a smoker, said smoking device including a lighter having electrical heating elements arranged in a fixed cavity, said device comprising: means for providing a paper carrier having zones of tobacco-flavored material; means for applying adhesive zones to the surface of the carrier to form spaced zones of adhesive between spaced zones of tobacco flavoring material; filter mounting means for mounting the filters on adhesive zones on the surface of the carrier; wrapping means for wrapping the carrier around the filter to provide a continuous rod with alternating zones of filter and tobacco flavoring material; and cutting means for cutting the continuous rod in the filter zones to form individual replaceable cigarettes. 106. The device from patent claim 105, characterized in that the means for setting filters are used for setting mostly cylindrical filters. 107. The device of claim 106, characterized in that the filter placement means are for alternate placement of free-pass filters and return filters on the adhesive zones, in order to achieve repetition of free-pass filter zones, tobacco flavoring material and return filters. 108. The device of claim 105, 106 or 107, characterized in that the cutting means serve to cut each filter substantially in half. 109. The device of claim 108, further comprising means for forming a rounded end for insertion on return filters. 110. The device of claim 108, further comprising means for placing a shield tube by which a generally cylindrical aerosol shield tube is placed on each free-pass filter, wherein the shield tube has a diameter greater than the diameter of the continuous rod and has a length substantially equal to of cut individual cigarettes. 111. The device of claim 110, further comprising: means for mounting a filter nozzle by which a generally cylindrical filter nozzle is mounted on a free-pass filter; and wrapping means for wrapping the aerosol protection tube and filter nozzle with wrapping paper. 112. A permanent heater assembly for use in a smoking device, which device includes a lighter, wherein the permanent heater assembly forms part of the lighter, for creating and delivering tobacco flavored smoke to the smoker, wherein the smoking device has a replaceable cigarette in which the tobacco flavoring medium is disposed along the first surface of the support, and the support has a second surface opposite the first surface, wherein the permanent heater assembly consists of; a heater base defining a first end of the cavity for receiving a replaceable cigarette, the cavity having an air passage from the first end to the second end to allow air to pass therebetween; and a plurality of permanent electric heaters located on the heater base, each heater having a surface adapted to be placed directly adjacent to another surface of the support, characterized in that, when the electric heating elements are activated, a corresponding portion of the tobacco flavor medium, which is with heating elements in such a relationship that heat transfer is enabled, it heats up, producing a previously determined amount of smoke with tobacco aroma to be supplied to the smoker. 113. A smoking device that creates and delivers tobacco-flavored smoke to a smoker, comprising: a permanent heater assembly including a heater base defining a first end of a cavity for receiving a replaceable cigarette, said cavity having a single air passage from the first end to the second end which allows air to flow between; a number of permanent electric heaters located on the base of the heater, each heater having a surface adapted to be placed directly next to the replaceable cigarette; source of electricity for powering a large number of permanent heaters; a control system for connecting permanent heaters to electricity in order to selectively turn on at least one of a plurality of permanent heaters; and a replaceable cigarette that is placed in the cavity of the heater in the closest proximity to a plurality of permanent heaters, characterized in that, when any one of the plurality of heaters is turned on, a corresponding portion of the tobacco-flavored material, which is in such connection with one of the heaters that heat transfer enabled, heats up, producing a predetermined amount of tobacco-flavored smoke to be supplied to the smoker. 114. The permanent heater assembly of claim 112 or 113, characterized in that the cavity is generally cylindrical, and characterized in that the assembly further comprises: a number of supporting heater arms extending from the first end of the base of the heater for carrying (supporting) a number permanent heaters, characterized by the fact that the arms are elongated, have an inner and outer surface and are arranged to define the surface of the cylinder. 115. The permanent heater assembly from claim 114, characterized in that a greater number of permanent heaters are mounted on the inner surface of the bearing arms of the heater. 116. The permanent heater assembly of claim 115, wherein the cavity is adapted to receive a return filter and the filter is positioned between the air passage of the heater base and the plurality of permanent heaters. 117. The permanent heater assembly of claim 116, characterized in that the return filter is generally cylindrical. 118. Permanent heater assembly from claim 112 or 113, characterized in that the cavity forms one ring; and characterized in that the heater assembly further comprises a plurality of supporting heater arms arranged from the first end of the heater base for carrying a plurality of permanent heaters, wherein the arms are elongated, have an inner and outer surface and are arranged to form the surface of the cylinder. 119. The permanent heater assembly from claim 118, characterized in that a greater number of permanent heaters are mounted on the outer surface of the supporting arms of the heater. 120. The permanent heater assembly of claim 119, wherein the cavity of the heater base is adapted to accept a return filter, the filter being positioned between the air passage in the heater base and the plurality of permanent heaters. 121. Permanent heater assembly from claim 120, characterized in that the return filter is ring-shaped. 122. Permanent heater assembly from patent claim 115, characterized in that a greater number of permanent heaters are made of silicon semiconductor material. 123. The permanent heater assembly of claim 122, characterized in that the silicon semiconductor material is doped with phosphorus impurities to a level in the range between approximately 5x1018 impurities/cm3 and approximately 5x1019 impurities/cm3. 124. Permanent heater assembly from patent claim 119, characterized in that the majority of permanent heaters are made of silicon semiconductor material. 125. The permanent heater assembly of claim 124, wherein the silicon semiconductor material is doped with phosphorus impurities to a level in the range between approximately 5 x 1018 impurities/cm3 and approximately 5 x 1019 impurities/cm3. 126. A smoking device for producing and supplying a smoker with a tobacco flavor, the smoking device comprising: a lighter, which lighter includes a heater base defining a first end of a cavity for receiving a replaceable cigarette, the cavity having an air passage from the first to a round end for allowing air to pass therebetween, a plurality of permanent electric heaters arranged on a heater base, each heater having a surface adapted to be placed immediately adjacent to a replaceable cigarette, an electrical power source for powering the plurality of permanent heaters, and a control system for supplying electricity to permanent heaters for selective heating of at least one of a larger number of heaters; and replaceable cigarettes, which cigarette includes a carrier having a first end and a second end and a first and a second surface, wherein the first surface defines a cavity for producing tobacco-flavored smoke between the first and second ends, and, characterized in that the second surface is positioned immediately adjacent electric heating elements, filter elements for filtering a predetermined amount of tobacco-flavored smoke before releasing it to the smoker, and a tobacco-flavored medium arranged on the first surface of the support, characterized in that, when any one of a plurality of electric heaters is activated, a corresponding portion of the medium with with the tobacco aroma, which is in such a connection with the heater elements that heat transfer is enabled, it heats up, producing at the same time a predetermined amount of smoke with the tobacco aroma to be supplied to the smoker. 127. A smoking device for supplying a smoker with tobacco-flavored smoke, the device comprising: a lighter, which lighter includes electric heating elements arranged in a fixed cavity, a source of electric power for powering the electric heating elements, and a control system for supplying electric power to the electric heaters elements for selective heating of at least one of the larger number of heating elements of the electric heater; and a replaceable cigarette, wherein the replaceable cigarette includes a support having a first end and a second end and a first and a second surface, wherein the first surface defines a cavity for producing tobacco flavored smoke between the first end and the second end, and, characterized in that the second surface is placed directly next to the electric heater, filter elements for filtering a previously determined amount of smoke with a tobacco aroma before releasing it to the smoker, and a medium with a tobacco aroma arranged on the first surface of the support; characterized by the fact that, upon activation of any one of a large number of heating elements, the corresponding part of the medium with a tobacco aroma is heated, which is in such a connection with one of the large number of heating elements that heat transfer is enabled, thereby producing a predetermined amount of smoke with a tobacco aroma to supply the smoker. 128. The smoking device of claim 113, characterized in that the energy source contains a battery. 129. The smoking device of claim 128, characterized in that the source of electrical energy contains a charger assembly connected to the battery to boost the battery voltage. 130. The smoking device of claim 129, characterized in that the battery is disposable. 131. The smoking device of claim 129, characterized in that the battery is rechargeable. 132. The device from patent claim 113, characterized in that the control system consists of: a system for selecting one of a large number of electric heaters; and a system for, when the smoker wants to draw smoke on the smoking device, supplying pulses of electrical energy to heat the selected heater. 133. Smoking device from patent claim 132, characterized in that the optional system is manual. 134. The smoking device of claim 132, characterized in that the selection system is automatic. 135. The smoking device from claim 134, characterized in that the automatic selection system selects each of a number of electric heaters. 136. The smoking device of claim 134 or 135, characterized in that the control system further comprises a sequential indication system for indicating the number of electric heaters that can be sequentially activated (heated) until all the electric heaters are activated at least once for the respective replaceable a cigarette. 137. The smoking device of claim 136, characterized in that the sequential indication system comprises a liquid crystal display. 138. The smoking device of claim 137, characterized in that the liquid crystal display indicates when the battery voltage drops below a preselected low voltage level (LOW) by repeatedly turning the display on and off. 139. The smoking device of claim 137, characterized in that the liquid crystal display indicates when the battery voltage drops below a preselected low (LOW) voltage level, and when the battery has been recharged to a preselected high (HIGH) voltage level after the voltage has fallen below the previously selected low (LOW) voltage level. 140. The smoking device of claim 137, characterized in that the liquid crystal display indicates when there is no replaceable cigarette in the lighter. 141. The smoking device of claim 137, characterized in that the liquid crystal display indicates when the heater assembly is not inserted into the lighter. 142. The smoking device of claim 132, characterized in that the pulse delivery system provides a pulse of predetermined duration. 143. The smoking device of claim 132, characterized in that the pulse delivery system provides a pulse of predetermined duration in the range of approximately 0.5 seconds to approximately 5 seconds, depending on the desired amount of energy to be delivered to the selected electric heater. 144. The smoking device of claim 143, characterized in that the pulse delivery system provides a pulse of predetermined duration ranging from approximately 1 second to approximately 3 seconds, depending on the amount of energy supplied to the selected electric heater. 145. The smoking device of claim 144, characterized in that the pulse delivery system provides a pulse of predetermined duration ranging from approximately 1 second to approximately 2 seconds, depending on the amount of energy supplied to the selected electric heater. 146. The smoking device from any one of claims 132 to 145, characterized in that the pulse of electrical energy contains a pulse of a previously determined amount of electrical energy. 147. The smoking device of claim 146, wherein the predetermined amount of electrical energy is from approximately 5 Joules to approximately 40 Joules. 148. The smoking device of claim 147, wherein the predetermined amount of electrical energy is from approximately 15 Joules to approximately 25 Joules. 149. The smoking device of any one of claims 132 to 148, characterized in that the pulse delivery system has actuating elements and provides a pulse in response to activation of said actuating elements by the smoker. 150. The smoking device of claim 149, characterized in that the actuating elements comprise a pressure sensor. 151. The smoking device from patent claim 149, characterized in that the activation elements are cyclically switched on and off in order to save the source of electrical energy. 152. The smoking device of claim 150, wherein the actuating elements are engaged for less than approximately 50% of the given time period. 153. The smoking device of claim 159, wherein the actuating elements are engaged for less than approximately 20% of the given time period. 154. The smoking device of claim 153, wherein the actuating elements are engaged for less than approximately 5% of a given time period. 155. The smoking device of claim 113 or any of claims 128 to 154, characterized in that the control system comprises a logic circuit with a programmable field area. 156. The smoking device of any one of claims 132 to 155, characterized in that the control system further comprises a voltage detection detector circuit for detecting the battery voltage when that voltage drops below a preselected low (LOW) voltage level and for detecting when the battery was recharged to a previously selected high (HIGH) voltage level after that voltage had fallen below a previously selected low (LOW) voltage level. 157. The smoking device of claim 156, wherein the preselected low (LOW) voltage level is lower than approximately 5 volts and the preselected high (HIGH) voltage level is above approximately 5 volts. 158. The smoking device of claim 157, wherein the preselected low (LOV) voltage level is in the range of approximately 3 to approximately 3.5 volts, and the preselected high (HIGH) voltage level is in the range of approximately 5 to approximately 6 volts. 159. The device from patent claim 113 or any of patent claims 128 to 158, characterized in that the carrier (bearing component) is composed of a non-woven carbon fiber network having a previously selected specific resistance, and characterized in that the specific resistance corresponds to a certain type of cigarette as would allow the lighter to distinguish between different types of cigarettes. 160. The smoking device from patent claim 159, characterized in that the control system contains: a system for selecting one of a number of electric heaters; and a system for, when the smoker wants to draw smoke on the smoking device, providing a pulse of electrical energy to heat a heater selected from a plurality of electric heaters. 161. The smoking device of claim 160, further comprising elements for measuring a previously selected specific resistance. 162. The smoking device of claim 161, characterized in that the first pulse of electrical energy is sent to heat the selected electric heater if the first pre-selected specific resistance is measured, and the second pulse of electrical energy is sent to heat the selected electric heater if the second pre-selected specific resistance is measured selected specific resistance.