SK69394A3 - Method and device for enlarging of bulk of tobacco - Google Patents

Abstract

This invention provides tobacco expansion processes and apparatus that can be employed for expanding tobacco at rapid throughput rates employing high pressure tobacco impregnation conditions. The processes and apparatus of the invention are particularly useful in tobacco expansion processes employing cycle times of less than 20 - 30 seconds; the use of preheated, prepressurized expansion agent such as propane; preheating of tobacco batches; and/or compression of tobacco within a high pressure impregnation zone for greatly improving use of available space in a high pressure impregnation vessel. <IMAGE>

Description

Method and apparatus no. increasing the volume of tobacco

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for increasing the volume of tobacco, and in particular to a method and apparatus for increasing the performance of the smell process and the economics of tobacco expansion.

BACKGROUND OF THE INVENTION

Over the past two decades, the methods of smelling cut tobacco have become an important component of the manufacturing process for cigarette production. Tobacco puff enhancement processes are used in particular to restore tobacco density, corresponding to the density and / or bulk of loose tobacco that has been lost during the treatment and storage of tobacco leaves. In addition, puffed tobacco is an important component of many low or very low tar cigarettes.

U.S. Pat. Nos. 3,524,451 and 3,524,452 disclose technological processes in which tobacco is contacted with an impregnating agent and then heated rapidly to vaporize the impregnating agent and increase the tobacco volume. U.S. Pat. No. 3,683,937 describes the impergence of tobacco with a gaseous impregnating agent followed by either heating or rapid depressurization to increase the tobacco batch volume.

The use of carbon dioxide to increase tobacco volume is described in US-PS 4,235,250 (Utsch), US-PS 4,258,729 (Burde et al.) And US-PS 4,336,814 (Sykes et al.). In these and related processes, carbon dioxide, whether in gaseous alego liquid form, is contacted with tobacco to impregnate the tobacco, and the impregnated tobacco is subjected to processing conditions to provide rapid heating of the tobacco to cause an increase in its volume. In the known expansion process carried out with carbon dioxide, it is particularly necessary to overheat the tobacco in order to achieve a significant and stable increase in the tobacco volume. However, this excessive heating of the tobacco may reduce the smell of tobacco and / or cause the formation of excessive amounts of fine tobacco particles. In addition, these processes, which use carbon dioxide for impregnation of the tobacco, lead to the formation of solid blocks of impregnated tobacco which contain dry ice, which must be disrupted prior to heat treatment, thereby increasing the complexity of the process.

U.S. Pat. No. 4,388,932 (Merrit et al.) Discloses a method of increasing the filling capacity of previously unfettered tobacco. Increased bulk tobacco having a "furnace volatile" (OV) content of less than 6 percent is heated to reduce the content of such volatile materials to less than 3 percent. The volatile matter (OV) content is substantially equivalent to the moisture content of the tobacco, as typically only not more than 0.9 percent by weight of the tobacco is volatile than the water. The tobacco obtained from the heating operation after expansion and sniffing, and having a very low volatile matter (OV) content, is then subjected to a treatment to obtain the original arrangement of the cut tobacco particles and increase in moisture, assuming that during regeneration The process results in less collapse of the tobacco particles than would occur without heat treatment after expansion. In this solution, it is proposed to stiffen the tobacco particles during the heat treatment in order to achieve increased stability of the expanded tobacco during its regeneration.

US-PS 4,531,529 (White and Conrad) discloses a method of increasing the filling capacity of tobacco by impregnating tobacco with a highly volatile low boiling expanding agent, for example halogenated hydrocarbons or hydrocarbons that are under normal operating conditions at expanding agent pressures and temperatures higher or near critical gas values. The pressure is released rapidly into the atmosphere, so the tobacco expands without the need for a heating operation to both increase the tobacco volume and stabilize the tobacco in a fluffy state. The pressure conditions of this f

of the process range from 3.6 MPa upwards, the upper limit of the pressure values being unknown. Pressures of less than 14.2 MPa are sufficient to achieve sufficient tobacco sniffing without excessive breakage of the tobacco particles.

US-PS 4 554 932 (Conrad and White) discloses a pressurized fluid treatment device for tobacco comprising a cylindrical hollow shell and a sliding coil unit displaceable therein in two opposite directions between a loading position outside the shell and a working position in inside the shell. When the coil unit is housed within the housing, the deformable sealing rings housed in grooves in the end disc portions of the coil unit are pushed radially outwardly into contact with the inner surface of the housing to form a pressure chamber within the cylindrical housing and between the disc end portions. . The annular pressure chamber formed inside the cylindrical housing is provided with conduits for supplying working fluids. The use of this device for high pressure tobacco impregnation with an expansion agent allows for easy filling of the chamber with tobacco and eliminates the problems of closing and opening its interior, associated with conventional anti-leak seals and locking mechanisms, such as occur with rotary autoclave caps. This pressure vessel can thus save time and increase economy by increasing tobacco volume.

The tobacco expansion methods described in the previous section, as well as other methods, must be carried out in batches when impregnating pressures greater than atmospheric pressure are used. Processes in which the tobacco is processed in batches require complex processing equipment and long cycle times, since considerable time losses arise during opening and closing of the pressure vessels and the introduction and removal of the impregnating agent from the pressure vessel. Some improvements aimed at increasing plant performance and the amount of tobacco processed per unit of time have been achieved by modifying the various devices used to shorten the duration of a single cycle. A substantial increase in the performance of the tobacco batch processing device can be achieved according to known techniques essentially only by increasing the volume of the individual systems and / or by increasing the number of individual batch spaces used simultaneously.

SUMMARY OF THE INVENTION

The drawbacks of these hitherto known processes are overcome in the tobacco bulk process and apparatus, which can be used to significantly increase production capacity through high pressure impregnation conditions for tobacco impregnation. The methods and apparatus of the invention comprise impregnation and expansion cycles with a duration of less than 20 to 30 seconds, the use of preheated and pre-compressed expansion agent, in particular propane, pre-heating tobacco batches and / or squeezing tobacco within the high pressure impregnation zone. which is available in the high pressure impregnation chamber.

The solution according to the invention substantially improves the degree of utilization of the tobacco storage space in the method of increasing the volume of tobacco by using impregnating working conditions in which high pressure is maintained. In another aspect, the device according to the invention provides systems for rapid delivery of tobacco batches for the reliable and economical delivery of pre-measured batches of tobacco to the impregnation zone and for rapid and economical preheating of individual batches of tobacco. The invention also provides an improved device operating at high operating speed and high pressure and comprising an impregnating device formed by a coil unit housed within the shell shell. According to yet another preferred embodiment of the invention, the device comprises an accumulation device for rapidly generating and supplying high pressure and high temperature impregnating gases, including combustible gases such as propane. The solution of the accumulator according to the invention minimizes the volume of gas present in the whole system at any time but also eliminates the need for expensive moving parts, which present many problems with known devices.

Substantial advantages in increasing the filling capacity of the device are achieved in a first embodiment of the method according to the invention, which is based on first impregnating the high humidity tobacco with an expansion agent in the high pressure impregnation zone for tobacco impregnation. to obtain tobacco with increased volume even at higher humidity, then the tobacco is dried after completion of the nose. The drying of the expanded tobacco is carried out, in particular, within a short period of time after the expansion of the volume has ended, for example less than 5 minutes after expansion. Although the high humidity of the tobacco fed into the high pressure impregnation zone could cause the tobacco particles to collapse after expansion in these processes that do not use heat to increase the tobacco volume, it has been found that when operating the process with increasing filling capacity, it increases with increasing moisture and can be maintained drying the tobacco to a moisture content of less than about 13 percent by weight in the time period following expansion. Preferably, the drying of the tobacco is carried out at temperatures of about 177 ° C or less, and the moisture content achieved is not to be less than 6 to 8 percent by weight, therefore the volatile fragrances are not removed from the tobacco.

In a preferred embodiment of the invention, the humidity of the tobacco fed into the impregnation zone is greater than 20 percent by weight, in particular greater than 24 percent by weight, to ensure a substantial increase in the degree of tobacco expansion. Tobacco with a particularly high degree of moisture is preheated to a temperature above 66 ° C prior to impregnation. The drying following the increase in the volume of tobacco carried out by the process of the invention ensures a high level of filling capacity of the increased volume tobacco.

In another preferred embodiment of the method according to the invention, the rapid delivery and pre-formation of the necessary doses for the impregnation of the tobacco and the subsequent increase in its volume are achieved. The apparatus adapted to carry out the method comprises a substantially vertical dispensing tube for forming a vertical column of tobacco. These metering tubes are associated with a separating device, provided in particular with a set of needles, and introduced into the tobacco column to be divided into a programmed upper part supported by a separating device, and a lower part under the separating device. Underneath the separating device there is a shut-off member, on which the tobacco column can be supported, which is thus supported on the shut-off member, however, when the dividing device is disengaged from the tobacco column. The closure member can be pulled out of engagement with the tobacco column, therefore, when the dividing device is inserted into the tobacco column, the release of the closure member results in the release of the lower portion of the tobacco column from the dispensing tube.

This amount of tobacco is then fed as a single dose into the impregnation zone. The tobacco batch volume can be easily controlled by varying the distance between the separating device and the closure member.

According to another preferred embodiment of the method according to the invention, the vertically oriented metering tube is also used for preheating the tobacco fed into the impregnation zone. According to a preferred embodiment of the invention, steam is injected into the metering tube at a location below the upper end of the tobacco column to heat the tobacco to a higher temperature between 38 ° C and 100 ° C, and the heated tobacco is then fed into the impregnation zone. In particular, a system for rapidly delivering tobacco and pre-metering the amount of tobacco described in the preceding section is used to feed the pre-heated tobacco in the form of individual doses into the impregnation zone. The pre-heating of the tobacco by this preferred particular embodiment of the method of the invention is rapid because the vapor spreads rapidly throughout the batch of tobacco. In addition, by increasing the steam, the tobacco is also preheated above the steam-injected area, whereby the upper tobacco layers simultaneously act as the tobacco insulator in the injection zone, hence the amount of heat required is reduced to a minimum.

In a further preferred embodiment, the vertically oriented metering tube is located above an opening in the upper wall of a horizontally arranged feed line for supplying tobacco batches to the high-pressure impregnation device. In this feed line, the compression parts movable in two opposite directions are displaceably disposed for conveying tobacco through the feed line and forcing the tobacco into a high-pressure working apparatus downstream of the feed line. The upper opening in the feed tube is connected to the feed tube and this connection is provided with a pivoting closing element which presses the tobacco into the feed tube. Thereby it is possible to feed tobacco of different density and supplied in batches of different volume into the impregnation zone, without the need to replace or modify the feed device.

The invention is also an improved solution of a coil unit and a cylindrical shell body according to US-PS 4,554,932 (Conrad and White) in order to achieve an increased durability of the tobacco processing results and a higher speed of operation. When the principle of this solution with a coil unit and a cylindrical shell is used in a preferred embodiment of the invention, the device operates at a speed of four to five cycles per minute or even faster. Thus, it is possible for the assembly comprising the coil unit housed in the cylindrical shell body to perform 3000 to 3600 or even more cycles in a twelve-hour day. Although this device increases the working speed and economy of tobacco sniffing, it has been found that repeated expansion of the elastomeric sealing rings radially outwardly on the cylindrical end pieces of the coil unit at high temperatures and high pressures may cause the sealing rings to expire prematurely.

The operation of the sealing rings is improved and their service life extension is achieved in such a particular embodiment of the invention by reducing the width of the radial gap between the coil unit and the inner surface of the cylindrical shell body at least one location axially adjacent to the sealing ring. This is achieved by placing the at least one annular element in the form of a ring of enlarged outer diameter which is a wear element and is disposed on each cylindrical end piece of the spool unit in a position that is axially adjacent and abuts the at least one axial face of the elastomeric sealing ring. In a more preferred embodiment of the invention, wear rings with an increased outer diameter are disposed on both sides of each elastomeric sealing ring. Because the wear rings have a larger circumference than the circumference of the cylindrical end pieces of the coil unit to prevent direct contact of the coil unit with the inner surface of the shell and scratching of its surface, the axial gap between the coil unit and the cylindrical shell is narrowed beside the wear rings. By placing the elastomeric sealing rings next to the wear rings, an improved axial support of the sealing rings is achieved if these sealing rings expand radially outwardly by large internal pressure. This again minimizes the destructive axial deformations of the circumferential portions of the sealing rings.

According to yet another preferred particular embodiment of the invention, the efficiency of the coil unit and cylindrical shell impregnation device is improved by increasing the rate of formation and removal of the high pressure gaseous expansion agent into the annular high pressure impregnation area within the shell. This object is achieved by providing gas inlet and outlet openings connecting the exterior space to the interior of the shell with a sufficient overall cross-sectional area, while providing these inlet and outlet openings with blocking or closing elements capable of minimizing the entry of tobacco particles.

In another particular embodiment of this basic solution, the gases are introduced at high pressure into the cylindrical shell and in turn removed therefrom by a plurality of interacting orifices in the shell that are distributed over the entire circumference of the cylindrical shell. The openings are surrounded by an annular space which is filled with the working fluid and which ensures its even distribution to the individual openings and to the interior of all the peripheral openings. The diameter of each orifice on the inside of the shell is smaller than the predetermined size of tobacco particles to prevent tobacco from entering the orifices.

In an alternative preferred embodiment, the cylindrical shell has at least one elongated opening having a larger diameter substantially greater than the size of the tobacco particles. Radially opposite this elongated aperture is an elongated locking member whose outer surface has a width greater than the width of the elongated aperture and extends from one portion of one end portion of the spool unit to the other end portion. When the chamber region of the coil unit, i.e. the space between the two cylindrical end pieces, moves within the cylindrical shell, the locking member overlaps the elongated opening, so that tobacco in the coil chamber cannot enter the elongated opening. Advantageously, two elongate holes are formed opposite each other in the cylindrical shell and a corresponding number of locking members are provided on the spool unit.

The invention also provides an improved high-pressure accumulator for generating and storing doses of a gaseous expansion agent having a high temperature and high pressure, in particular propane at a temperature above 121 ° C and a pressure above 172.3 MPa. In the prior art devices, for supplying high temperature and high pressure propane to the impregnation zone at a rate sufficient for four to five duty cycles or more, it would be necessary to either store or use an accumulator in the form of a pressure vessel having chambers separated from each other by movable members. The inert compression gas was stored in one chamber and the propane was stored in the other chamber. During the periodic replenishment of propane into the pressure chamber and its withdrawal, the movable member moves within the pressure chamber and may be damaged over time.

The accumulators of the present invention consist of a high-pressure vessel containing both an expansion agent and a gaseous pressurizing agent inside the vessel but which is not provided with any separating member between the expanding agent and the pressurizing agent. In one preferred embodiment of the accumulator, the interior is maintained at a temperature above the critical temperature of both the pressurizing agent and the expanding agent and under a sufficiently high pressure to have both the pressurizing agent and the expanding agent having a high density close to that of the liquid. The squeezing agent is selected with respect to its diffusion properties relative to the expanding agent such that both of them can be kept in contact with each other and, to an extremely low degree, are mixed by diffusion occurring between the two retention agents under the conditions prevailing inside the container. In particular, the pressurizing gas is nitrogen and the expansion agent is propane. At pressures higher than 172.3 MPa and temperatures above 93 ° C, the two gases can be kept substantially separate from each other in the vessel, therefore the propane can be cyclically replenished and withdrawn from the vessel with very low nitrogen losses due to its penetration into the propane.

In a further preferred embodiment of the accumulator according to the invention, the expansion agent and the gaseous pressurizing gas are held within a high pressure vessel comprising a first zone and a second zone adapted to separately store two fluids at near-supercritical temperature and pressure conditions and a third zone. which is in fluid communication with both the first and second zones and which is adapted to store a barrier fluid between the fluids in the first and second zones. The barrier fluid, which may be water, prevents a significant mixing of the pressurizing agent with the expansion agent.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail with reference to the drawings, in which: FIG. 1 is a schematic cross-section of one of the preferred embodiments of the impregnation device used in the invention, with various operating positions, some of which are shown in dotted lines; FIG. 1A is a schematic cross-sectional view of an accumulator which may be advantageously used together with the apparatus of FIG. 1 for rapidly supplying a high pressure and high temperature impregnating agent to the apparatus and comprising a first and a second zone adapted to separately maintain two fluids at temperature and pressure conditions approaching or exceeding supercritical values, and an area interconnected by the fluid column with the first i a second zone for maintaining a barrier liquid between the liquids in the first and second zones, FIG. 2 is a cross-sectional view of a tobacco feeding and loading device comprising a pair of vertically oriented dispensing tubes adapted to supply a pair of horizontally oriented pipes disposed upstream of the impregnation device of FIG. 1, FIG. 2A is an enlarged longitudinal sectional view of one end of the back-sliding compression member disposed in the loading duct of the loading device of FIG. 2, FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2, which is connected to the metering tubes of the device according to FIG. 2 for supplying steam to the tobacco column; FIG. 4 is an enlarged cross-sectional view taken along line 4-4 of FIG. 2, a second exemplary embodiment of a steam injection device connected to the metering tubes of the device shown in FIG. 2, FIG. 5 is an enlarged cross-sectional view taken along line 5-5 of FIG. 2, a preferred exemplary embodiment of a tobacco column separator associated with the metering tubes; FIG. 6 is a front view of the lower portion of the dispensing tube of the device of FIG. 2, shown partially in section along line 6-6 of FIG. 5 and comprising a plurality of brushes connected to a tobacco column splitter; FIG. 7 is an enlarged schematic cross-section through part of the supply device of FIG. 2 showing the injection device for injecting steam, the splitting elements for dividing the tobacco column, and the closing element for dispensing a predetermined amount of tobacco into the impregnating expansion device of FIG. 1, FIG. 8 is a cross-sectional view of one end portion of the coil unit housed in the cylindrical shell of the device of FIG. 1 showing cross-section of the sealing and wear rings connected to the end parts of the coil unit, this example also showing circumferentially spaced openings extending through the shell wall for supplying working fluids to the impregnation zone; FIG. 8A is a greatly enlarged cross-section of a portion of the device shown in FIG. 8 and illustrating a preferred embodiment of the individual apertures forming the passages through the wall of the shell; FIG. 9 is a schematic cross-sectional view of a tobacco drying dryer utilized downstream of the impregnating device of FIG. 1, FIG. 10 is a longitudinal section through part of an alternative embodiment of a fluid supply arrangement with a coil unit mounted in a cylindrical shell as in the apparatus of FIG. 1 in which the coil unit is engaged in movement between the loading position and the impregnation position, in which elongated holes are formed in the cylindrical shell and radially opposed locking elements are arranged on the coil unit, FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. 10 and illustrating how the locking members on the coil unit block the holes through the shell as the coil unit passes through the shell; FIG. 12 is an enlarged axonometric view of an elongated locking element selected from the device of FIG. 10 and 11, FIG. Fig. 13 is a graph showing the increase in tobacco volume as a function of tobacco moisture and the various stages of tobacco preheating; 14 is a graph illustrating how tobacco expansion can vary in tobacco of different density during impregnation with an expansion agent and at different impregnation times; and FIG. 15 is a graph derived from the composite expansion data illustrating the flexibility of the method of increasing the volume of tobacco and the apparatus of the invention and indicating the overall increase in tobacco volume per hour (in cubic meters per hour) that can be achieved by the apparatus of FIG. 1 as a function of the impregnation time and tobacco compression.

Examples of the invention

In the following description, various exemplary embodiments of the method and apparatus of the invention are explained in more detail. While the invention has been elucidated by specific exemplary processes and devices, including those shown in the drawings, it is to be understood that the scope of the invention is by no means limited to these exemplary embodiments. On the contrary, the invention encompasses a number of other alternative embodiments and structural modifications which will be apparent to those skilled in the art from the foregoing sections and from the following detailed description of exemplary embodiments of the invention.

Fig. 1 schematically illustrates the process of an exemplary embodiment of an impregnation process and an exemplary device of the invention comprising a coil embedded in a cylindrical shell as described in U.S. Pat. The various details of the design of US-PS 4,554,932 are no longer re-introduced in order to maintain a useful brief description. If necessary, these details can be discussed directly in this U.S. Pat. No. 4,554,932.

As schematically shown in FIG. 1, the tobacco is first prepared and processed in the pre-treatment zone 10 to increase its moisture to a value greater than 16 percent by weight, in particular greater than 20 percent by weight. The tobacco with increased humidity then enters the feed zone 12 in which the tobacco is heated by the process described in more detail below and then fed back to the coil body and slidable in a cylindrical shell forming the high-pressure device for the tobacco. processing of tobacco with working fluid.

The high pressure processing device with a coil bearing body and a cylindrical shell comprises a pressure vessel consisting of a cylindrical shell 14 in the form of a hollow cylindrical housing and a coil unit 1.6. The cylindrical shell 14 and the coil unit 16 may be made of any material, especially stainless steel and the like. When designing and dimensioning these parts of the device, it should be borne in mind that these parts must withstand pressures comparable to those present in the pressure receptacles, as will be evident from the next section.

The coil unit 16 comprises cylindrical end portions 18 and a connecting rod 20. If the coil unit 16 is housed within a cylindrical shell 14, as shown in FIG. 1, the end portions 18 together with the connecting rod 20 and the cylindrical shell 14 form an annular space of predetermined volume forming a sealed impregnation chamber 22 or zone. The spool unit 16 is horizontally disposed and is adapted to perform a backward movement in two opposite directions between the loading position 24 shown by the dotted lines, the unloading position 26 shown by the same dotted lines and the impregnation position shown in FIG. 1 solid lines. The coil unit 16 is connected in the axial direction by a shaft 28, shown only partially in FIG. 1, with a quick acting hydraulic piston or other drive device (not shown) for controlling the movement of the spool unit 16 between the three positions.

The bobbin unit 16 is loaded with tobacco at the loading position 24, as described in more detail below, and the bobbin unit 16 is then moved to the impregnation position. In the impregnation position, the coil unit 16 is sealed within the cylindrical shell 14 and the seal is provided by radially expanding the elastomeric sealing rings 3.0, which are housed in annular grooves formed in each of the coil end pieces 18. The construction of the elastomeric sealing rings 30 is described in more detail. In the following, when explaining the example of FIG. 8th

The sealing rings 30 are formed of a deformable elastomeric material, for example vulcanized rubber, and are adapted to supply hydraulic fluid to their inner annular space through a supply line 32. Hydraulic fluid, such as food oil, is injected into the supply line 32 from a hydraulic accumulator 34. Hydraulic the liquid is injected into one end of the spool unit 16 through a hole extending through the connecting rod 36, shown partially in FIG. 1 and connected to at least one end of the coil unit 16. The hydraulic fluid presses on the inside of the wall of the sealing rings 30 and causes them to expand outwardly so that the annular space forming the pressure impregnation chamber 22 is sealed against leakage on both sides.

The inlet and outlet gas conduits 38 for the high pressure gas 38 are connected to the interior of the cylindrical shell 14 via a plurality of openings 42, as will be described in more detail in the explanation of the example of FIG. These openings 42, which may be spaced around the circumference of the cylindrical shell 14, as shown in FIG. 8, or the enlarged longitudinal and cross-sections of FIG. 10, 11 and 12, and which provide for the introduction and removal of the high pressure fluid into the pressure impregnation chamber 22 formed by the annular space, however, when the coil unit 16 is in the impregnation position. The apertures 42 are surrounded by a distributor piece 45 that defines an annular space 44 containing working fluid supplied to the cylindrical shell 14 through peripheral apertures 42. The high pressure fluid flows through the peripheral apertures 42 and then enters the tobacco stored and compressed around the spool tie 20 through the aperture and ducts. in the coil body shown in FIG. 8 and will be described in more detail below.

To control the rapid supply and discharge of fluid to the impregnation pressure chamber 22, the device is provided with a pair of quick acting valves 46, 48. These valves 46, 48 may in particular be ball valves having an inlet diameter in the range of 12.7 mm to 43.2 mm; even greater, depending on the size of the pressure impregnation chamber 22, to achieve substantially instantaneous admission of the high pressure fluid into the pressure impregnation chamber 22 and its removal. In particular, the valves 46, 48 are opened and closed automatically by means of a quick-acting actuator (not shown).

At the inlet side, the high pressure gas line 38 is connected to an accumulation unit in the form of an accumulator 50, which will be described in more detail in the supply to the accumulator. The accumulator 50 may be a device (not shown) of the description below.

A heating unit 52 is also used to heat the gas 50, also heated by means of others, which take care, in particular, of maintaining the fluid inside the accumulator 50 in a heated state. Upstream of the heater unit 52 upstream of the gas flow is a high pressure pump 54 that provides high pressure gas supply, e.g., 172.4 MPa, to the heater unit 52 and the accumulator 50. The discharge gas line 50 serves to discharge the high pressure fluid from the pressure The impregnation chamber 22 is connected to a zone (not shown) for recovering selected gases of the fluid discharged from the pressure impregnation chamber 22.

The accumulator 50 is used to prepare a high pressure fluid such as propane having a pressure of 172.4 MPa and supply it to the impregnation zone of the coil impregnator shown in FIG.

1. The accumulator 50 is a cylindrical container 56 made of a material capable of withstanding high temperatures and pressures. On the upper side and the lower side of the accumulator 50, respective inlet openings 58, 60 are provided for supplying high-pressure gases.

An inert high pressure gas such as nitrogen having a pressure greater than

172.4 MPa is fed through the first inlet port 58 and, due to the pressure and temperature conditions inside the vessel 56, is maintained separately in the upper zone 62 of the cylindrical vessel 56, while the expansion fluid, e.g. propane, is fed through the second port 60 and maintained The cylindrical vessel 56 is maintained at a temperature and pressure that approach or exceed the critical temperatures and pressures of both the pressurizing fluid and the expansion agent. Under these conditions and using selected substances, particularly nitrogen as the compression fluid and propane as the expansion agent, the gas diffusivity in the two fluid zones 62, 64 can be kept sufficiently low so that these fluids are kept within the accumulator 50 substantially separated from each other. .

Upon removal of the expansion gaseous agent from the accumulator 50, a pressure drop is detected by means of sensors (not shown) and the controller actuates a pump 54, which immediately replenishes the accumulator 50 with a high pressure expansion agent, in particular propane. The pressure sensor may be located within the accumulator 50 or may be part of the pump 54. The gas accumulator 50 is supplemented with gas for a short period of time ranging from 5 to 30 seconds during the time interval reserved in the invention for tobacco impregnation in pressure impregnation. the chamber 22 shown in FIG. First

As shown by the double arrow 65 in FIG. 1, the level of expansion agent within the accumulator 50 may fluctuate cyclically between the predetermined upper level and the predetermined lower level when replenishing and withdrawing the substance. The lower level is selected such that it is still at a predetermined distance from the bottom of the cylindrical vessel 56 so that the escape of the expansion agent does not cause the escape of the pressurizing gas. The lower level is also selected with a view to preventing the expansion agent from escaping from the interface area between the two fluids. However, if propane gas and nitrogen gas are used in the apparatus, the lower level for the propane gas can be chosen in particular about 30 cm, and other distances can be set according to the size of the cylindrical vessel 56 and the internal conditions as will be apparent from the rest of the description.

The level sensing and regulating means 10 can be used to assist in maintaining the level of the expansion agent, for example propane, in a predetermined range as mentioned in the previous section. It is also advantageous to use liquid interface sensors or the like for sensing the boundary between the expanding agent and the pressurizing agent. An integral or standalone control system responds to the fluid interface sensor signals and controls the supply of, or withdrawal of, a pressurizing fluid, such as nitrogen gas, to or from the accumulator 50 to maintain the expansion agent level between predetermined upper and lower levels.

After the expansion agent has been removed, another fresh charge of the expansion agent is pumped back into the accumulator 50 until a predetermined upper pressure value is reached. The predetermined upper pressure value is selected first based on the total combined volume of the accumulator container, the pressure impregnation chamber 22 and the gas line 38 between the accumulator 50 and the pressure impregnation chamber 22, and secondly based on the desired pressure in the impregnation zone. Since the pressure in the accumulator 50 decreases as gas is discharged into the gas line 38 and then into the impregnation zone of the pressure impregnation chamber 22 as the gas has more space, the upper pressure value must be large enough to reach the resulting pressure of the gaseous expansion agent in the impregnation zone. a predetermined pressure value corresponding to the impregnation pressure for tobacco impregnation. Where the final pressure is about 172.4 MPa, the upper pressure must be

186.1 MPa to 206.8 MPa, depending on the influence of these factors.

Typically, however, there is some loss of compression fluid over the operating time, due to the absorption of the compression fluid by the expansion agent during its contact with the compression fluid during its presence in the accumulator 50. Although low gas diffusivity occurs between the fluids in the accumulator 50, which, in theory, allows the two fluids to be kept separate, even at extremely low diffusivity values of the two gases in the accumulator 50, a small amount of compression fluid is discharged together with the expansion agent, since both fluids have been partially mixed. However, the small extent of absorption of the pressurizing fluid generally has no adverse effect on tobacco expansion.

However, if the system of the invention includes a recovery device for recycling the expansion agent, recovery of the expansion agent immediately following the use of the expansion agent will result in separation and recovery of all absorbed compression fluid, therefore substantially pure expansion agent for recycling can be recovered. . The absorbed compression fluid is generally not recoverable, and moreover, the presence of the absorbed compression fluid in the expansion agent reduces the amount of expansion agent that can be recovered economically after use. The amount of compression fluid absorbed in the expansion agent is an equilibrium amount determined based on the diffusivity value of the two fluids at the temperature and pressure prevailing within the accumulator 50, the turbulence within the accumulator 50, and is in particular less than 5% by weight.

An accumulator 50 adapted to minimize absorption of the pressurizing fluid by the expansion agent is shown in FIG. 1Λ. This accumulator 50 'uses a third fluid of greater density, for example water, in the region separating the expansion agent from the compression fluid to form a separation zone separating the expansion agent from the compression fluid. As shown in FIG. 1A, the accumulator 50 'comprises a first zone 62' for receiving a pressurizing fluid, particularly nitrogen, and a second zone 64 'for receiving the expansion agent and keeping it separate under severe high temperature and pressure conditions. The third zone 61 is in fluid communication with both the first zone 62 'and the second zone 64' and maintains a more dense fluid, especially water, as a barrier fluid between the fluids in the first zone 62 'and the second zone 64'.

The barrier fluid shown in the accumulator 50 'of FIG. 1A, restricts significantly or even eliminates mixing with one another f

the expansion agent and the compression fluid even under conditions where fluid swirling occurs. This feature of the invention reduces the consumption of the pressurizing fluid and the consequent loss of the expansion agent during its regeneration and may thus simplify the construction of a recovery system for recovering the expansion agent because of the separation of absorbed fluid by the condition. In the accumulator 50 'shown the expansion agent, in particular propane, only a small one is no longer shown in FIG. 1A, the amount by the base absorbs a barrier fluid, for example water.

The accumulator 50 'is supplied with water, as well as nitrogen separately, and their level is monitored by separate LC level detection devices as shown in FIG. 1A, which are additionally connected in combination with integral or separate control units for controlling the supply of water and nitrogen N2 to the accumulator 50 '. These control operations respond to the LC purging level detector and provide the addition of water at a rate and rate per unit of time sufficient to maintain the total amount of water in the accumulator 50 'between predetermined upper and lower limit levels. In addition, the control device provides additional nitrogen supply or withdrawal, depending on the level detector signals, to maintain the interface between water and nitrogen at a level within predetermined limit positions.

In the accumulator unit shown in FIG. 1A, the second zone is 64 /. wherein the expansion agent is maintained substantially separately in a partially closed cylindrical chamber disposed within the upper portion of the larger pressurized container. This or a similar arrangement is particularly advantageous in a system according to the invention using a barrier fluid having a greater density than the compression fluid and also an expansion agent. It is obvious that this design and arrangement is only one of the possible preferred exemplary embodiments

The invention and others may be used

Containers for forming a movable fluid layer to separate other fluids within the container.

Fig. 1 and 1A illustrate preferred embodiments of the battery 50, 50 'according to the invention, but other devices providing virtually instantaneous delivery of the high pressure and high temperature expansion agent may also be used. Such a device may be provided with a container containing only a high density expansion agent maintained above the supercritical temperature. However, if the vessel contains a relatively large amount of expansion agent compared to the amount of expansion agent withdrawn in each cycle and if the expansion agent is maintained at a high density, the expansion agent can be removed from the vessel with only a small pressure drop in the expansion agent.

For example, at a pressure of 20 psi and a temperature of 149 ° C, the density of propane is

380.6 kg / m ³ . At the same temperature and pressure of 172.4 MPa, the density of propane is 365.2 kg / m ^3. This implies that a vessel containing one cubic foot (28.3 dm ³ ) and containing a propane fluid maintained at a pressure of 189.3 MPa and At 149 ° C, 0.44 kg of propane at 149 ° C can be discharged to the impregnation zone with only a small pressure drop which decreases from 189.3 MPa to 172.4 MPa.

In yet another exemplary embodiment of the invention, it is possible to use a mechanical accumulator to supply the expansion agent. One such mechanical battery currently recommended for use is the Parker Bertea Aerospace Metal Bellows', Parker Hannfin Corp., Metal Bellows Division of Moorpark, California.

In the example of FIG. 1, the pressure of the propane introduced into the pressure impregnation chamber 22 is in particular higher than 137.9 MPa, preferably between 172.3 MPa and 206.8 MPa. In accordance with the present invention, it has been found that using these pressures achieves extremely short impregnation times for the impregnation of tobacco, ranging between 5 and 15 seconds, while achieving a very significant increase in the tobacco filling capacity, which is increased, for example, by 50% to 100%. The temperature of the propane is preferably maintained above 138 ° C, in particular between 149 ° C and 204 ° C, for example around 149 157 ° C. This ensures the supply of gentle heat for heating the tobacco in the impregnation zone.

In FIG. 2 shows a preferred exemplary embodiment of a tobacco inlet and feed device. Tobacco in any form, including tobacco leaves, with stalks and veins, strips of tobacco from which stalks and veins are removed, cigarette fillings, cut cigarette fillets consisting of cut or crushed cigarette strips, in particular in the form of cut filler strips, are moistened in block 66 by means of known devices, the design of which is readily apparent to those skilled in the art to achieve a moisture content of at least 13% and preferably at least 20%, and then the tobacco passes through the pneumatic conveying line 68 to the metering device 70.

The dosing device 70 is in the illustrated embodiment formed by two separate dosing tubes 72, 74. Each of the dosing tubes 72, 74 has a substantially rectangular cross-section whose size is continuously increased in the direction of tobacco travel. As will be appreciated by those skilled in the art, the dispensing tubes may have other designs, such as a circular cross-section.

The tobacco coming from the conveying line 68 enters a feed valve 76, which is located on the top of the metering tubes 72, 74. In the system of the invention, the fill valve 76 may be any valve used in the prior art for supplying solid materials such as tobacco. An example of such a filling valve 76 may be a rotary valve with a plurality of blades shown in FIG. 2. The tobacco material thus supplied forms substantially vertical columns of tobacco in each of the metering tubes 72, 74. These vertical tobacco columns have a predetermined height which is monitored in each of the dispensing tubes 72, 74 by height sensors for sensing the height of the tobacco column. The height of the tobacco column is preferably between 90 cm and 120 cm in each of the dispensing tubes 72, 74. However, if the tobacco level falls below a predetermined minimum value in any of the metering tubes 72, 74, the height sensors 78 actuate the feed valve 76, so additional quantities of tobacco are fed into the metering tubes 72, 74 until the desired height is reached. .

After the tobacco has been divided and fed to each of the dispensing tubes 72, 74, a preheating steam treatment is initiated which further increases the moisture content of the tobacco. The pre-heating of the tobacco provides heat to create suitable conditions for the short-term cycle in the impregnation zone. In addition, the additional moisture supplied to the tobacco serves the function of ensuring good results in increasing the tobacco volume and enhances the suppleness of the tobacco. In the solution according to the invention, it has been found that if tobacco is introduced into the pressure impregnation chamber 22 with a moisture content of more than 20% by weight, in particular between 24% and about 30% by weight, and when preheated to a temperature greater than 66 ° C more sniffing. In carrying out the method of the invention, the tobacco is both humidified and preheated by steam injected into each of the dispensing tubes 72, 74. Steam heating is advantageous in that the heat can be efficiently and effectively transferred to the tobacco at the same time as its moisture is increased. In addition, since the tobacco comes into contact with the steam in the dispensing tubes 72, 74, the tobacco layers above the steam injection area or regions act as insulating layers, thereby increasing the efficiency of using steam injection to heat the tobacco.

The steam is injected into each of the metering tubes 72, 74 at locations below the upper end of the tobacco column in the metering tubes 72, 74. In FIG. 2, two steam injectors 80, 82 are shown, which will be described in more detail below. These steam injectors 80, 82 require dry steam, which can be provided by preheating or external heating of the steam pipes and pipes to prevent condensation. The temperature of the steam injected into the tobacco is sufficiently high to heat the tobacco to a temperature above ambient temperature, in particular above 52 ° C, more preferably above 66 ° C, for example from 66 ° C to 93 ° C.

Fig. Figures 3 and 4 show two exemplary embodiments of a steam injection device for tobacco columns. In FIG. 3 is a sectional view taken along line 3-3 of FIG. 2. The steam is injected via supply lines 84 into the outer manifold chamber 86 surrounding the dispensing tube 72. The distribution chamber 86 is spaced apart from the outer wall of the dispensing tube 72 and forms an annular enclosure 88 in which the injected steam is contained. The distribution chamber 86 communicates with the interior of the dispensing tube 72 by a plurality of apertures 90 disposed on two mutually opposed walls of the dispensing tube 72. The vapor passing through these apertures 90 penetrates into the tobacco column, as indicated by the arrows in FIG. Third

Fig. 4 shows another preferred embodiment of the steam injection device by which steam is injected into the tobacco column. In this FIG. 4, the device is a second injector 82 in the form of a retractable fork unit formed by a hollow bridge 92 that carries a plurality of hollow perforated nails 94. The steam injector 82 is disposed horizontally and can perform sliding movement in two mutually opposite directions between a first position on the outside of the dispensing tube 72 and a second position within the dispensing tube 72. The second injector 82 is connected by piston rod to a hydraulic cylinder with piston movement of this injection device between the two extreme positions, hence the hollow perforated nails 94 penetrate into and out of the tobacco column as indicated by the double arrow in FIG. 4. After the hollow perforated nails 94 have been inserted into the tobacco column, they are forced into them by the supply line 96 para, which enters the hollow bridge 92 and then into each of the hollow perforated nails 94 of the plug-in unit. The vapor then exits the hollow punched nails 94 through a set of injection ports 98 in each hollow punched nail 94. and enters the tobacco column as indicated by the arrows.

Although FIG. 2 shows the use of both types of injection devices for steam injection, it will be apparent to those skilled in the art that only one of them is sufficient in practice. However, it is preferred to use a combination of two steam injectors to ensure that the steam is evenly injected throughout the cross-section of the tobacco column.

In particular, the steam injectors 80, 82 of the invention are located at locations along the tobacco column selected so that substantially all of the steam injected into the tobacco column condenses before reaching the upper end of the tobacco column. The injected vapor moves upward inside the tobacco column and heats the tobacco in the column as it moves. Heat is gradually lost from the steam and the steam then condenses on the tobacco as its moisture until all the steam condenses.

After it has been preheated and humidified, the tobacco moves down the column in the column and is fed into the feed lines 110 shown in FIG. 2. A tobacco column splitting device 112, shown in FIG. The cutting device 12 has its working tool as retractable in two opposite and substantially horizontal directions as the nail steam injector 82, the tool moving between a first position outside the tobacco column and a second position within the column.

A top view of a preferred embodiment of the separating device 112 is shown in FIG. 5. As shown in FIG. 5, the tobacco column splitter 112 includes a control bar 114, a support bridge 116, and a plurality of spaced nails 118. The splitting device 12 moves between the first and second end positions to divide the tobacco column into an upper portion and a lower portion, and thus separating a predetermined amount of tobacco, representing a single dose, which is then withdrawn from the lower end of each tobacco column. When the nails 118 are inserted into the tobacco column through the apertures described in more detail below, the upper portion of the tobacco column above the dividing device 112 is supported by the nail system 118. The nails 118 are relatively close together, for example at 6 mm to 25 mm distances. or up to 38 mm. The lower portion of the tobacco column under the nails 118 then enters the feed line 110 in the form of a batch of tobacco.

The tobacco column dividing device 112 provided with nail-like dividing elements is preferably vertically adjustable for optionally extending into the tobacco column at several predetermined and vertically preset positions. In FIG. 7 shows a range H of heights at which the position of the tobacco column splitter 112 can be locked. By this design, the possibility of changing the amount of tobacco per batch delivered to the feed line 110 is obtained, since by locking the position of the dividing device 112, the amount of tobacco taken from the lower end of the tobacco column is adjusted.

The nails 118 of the dividing device 112 penetrate into the tobacco column by a plurality of vertical elongated slits that are formed against the nails 118 in the double wall of the portion of the dispensing tube 72, as best seen in FIG. 6 and 7. FIG. 6 shows a first outer side wall 120 of this portion of the dispensing tube 72 which is provided with elongated vertical slits 122. The outer side wall 120 is shown in FIG. 6 partially cut to show the inner side wall 124 of the double portion of the dispensing tube 72 spaced from the outer side wall 120 and comprising a second row of vertical slits 126 facing the first vertical slits, and a plurality of horizontal brushes 128 associated with the vertical slits 126. A plurality of second brushes 130 may then be associated with the outer side wall 120. The double-walled structure of this portion of dispensing tube 72 serves as a containment tank that retains tobacco particles that adhere to the nails 118 of the splitting device 112 while pulling the nails 118 from the tobacco column. The brushes 128, 130 wipe the adhered tobacco particles from the surface of the nails 118. As they are pulled from the interior of the tobacco column to a position outside the outer side wall 120, the nails 118 come into contact with the rows of brushes 128, 130 and the tobacco particles wipe off the surface. they fall into the gap 132 between the two side walls 120, 124. The tobacco particles fall through the gap 132 between the two side walls 120, 124 into its lower part and fall out of the drop hole 134 formed at the lower end of the gap 132.

A shut-off member 140, in particular in the form of a rotary valve, is connected to the lower end of each of the metering tubes 72, 74. The closure member 140 is positioned in the path of the advancing tobacco column in a vertical position below the dividing device 112 to support the tobacco column while the dividing device 112 is disengaged from the tobacco column. The locking closure member 140 is released from the tobacco column to release the lower portion of the tobacco column below the dividing device 112 and to feed it to the feed line 110.

In particular, the locking closure member 140 is an air operated rotary valve. The air shut-off rotary valve may have some of the known designs known to those skilled in the art, and preferably consists of a rotary valve without rotary blades operating intermittently and capable of receiving and delivering one batch of tobacco at a time, as shown in FIG. 7. The bladeless rotary valve of FIG. 7 includes a housing 142 housing a rotating bucket wheel 144 which can rotate about its centerline within the housing 142. In the apparatus of the invention, a continuous shut-off air shut-off valve provided with a paddle assembly may also be used.

A group of second brushes 130 can then be associated with the outer side wall 120. The double-walled structure of this portion of dispensing tube 72 serves as a collection tank that retains tobacco particles that adhere to the nails 118 of the splitting device 112 as the nails 118 are pulled out of the tobacco column. Brushes 128, 130 wipe the adhered tobacco particles from the surface of the nails 118. As they are pulled from the interior of the tobacco column to an outside position from the outer side wall 120, the nails 118 come into contact with the rows of brushes 128, 130 and the tobacco particles wipe off the surface. and fall into the gap 132 between the two side walls 120, 124. The tobacco particles fall through the gap 132 between the two side walls 120, 124 into its lower part and fall out of the drop hole 13 formed at the lower end of the gap 132.

A shut-off member 140, in particular in the form of a rotary valve, is connected to the lower end of each of the metering tubes 72, 74. The closure member 140 is positioned in the path of the advancing tobacco column in a vertical position below the dividing device 112 to support the tobacco column while the dividing device 112 is disengaged from the tobacco column. The locking closure member 140 is released from the tobacco column to release the lower portion of the tobacco column below the dividing device 112 and to feed it to the feed line 110.

In particular, the locking closure member 140 is an air operated rotary valve. The air shut-off rotary valve may have some of the known designs known to those skilled in the art, and preferably consists of a rotary valve without rotary blades operating intermittently and capable of receiving and delivering one batch of tobacco at a time, as shown in FIG. 7. The bladeless rotary valve of FIG. 7 comprises a housing 142 housing a rotatable bucket wheel 144 which can rotate about its central axis within the housing 142. In the apparatus of the invention, a continuous shut-off air shut-off valve provided with a paddle assembly may also be used.

The closure member 140 is shown in FIG. 7 in an empty position in which it supports the tobacco column. If an additional batch of tobacco is to be removed from the lower end of the tobacco column, the nail splitting device 112 is inserted into the tobacco column and the closure member 140 is rotated 180 ° from its stop position to a receiving position in which it can be filled with tobacco and the wheel 144 rotated with its open side 146 upward and coupled to the lower end of the tobacco column. In this position, the bucket wheel 144 receives tobacco from the bottom of the tobacco column and then rotates 180 ° again to a position where it delivers a pre-measured dose of tobacco to the feed line 110. The use of air damper rotary valves as shut-off member 140 is particularly preferred. because in its dispensing position shown in FIG. 7, the valve blocks and supports the tobacco column and at the same time, by means of its gasket 14 8, ensures complete separation of the tobacco column from the impregnation zone into which the expansion agent is supplied.

The system of the present invention for dispensing single doses of tobacco provides a number of advantages. In particular, it is possible to easily and precisely control the amount of tobacco delivered to the impregnation zone. To regulate this amount, the dividing device 112 can be moved vertically to different height positions to produce batches of tobacco of any desired volume for subsequent impregnation. In addition, the use of the metering tubes 72, 74 provides a substantially uniform distribution of the tobacco batch across the width of the feed line 110 below them. The dispensing of the tobacco batch is rapid and is able to ensure that each batch of tobacco is delivered to the impregnation zone in accordance with the short duration of the impregnation cycles of the system of the invention.

As can be seen from the perspective of FIG. 2, the predetermined amount of tobacco is thus transferred to the feed lines

110, by means of which the annular space of the coil unit 16 of the impregnation device is filled. As shown in FIG. 2, the individual tobacco batches 150 are loaded into the annular space of the bobbin unit 16 in the loading position 24 shown in FIG. 1, by means of a pair of mutually opposed semi-cylindrical loading and squeezing parts 152, which are mounted in the loading ducts 110 in translational retraction. The loading ducts 110 are preferably rectangular in cross-section and are made of a material capable of withstanding abrasion and wear caused by repeated horizontal movements within the loading chambers, for example of hardened aluminum. In addition, it is preferred that the upper and lower surfaces of the loading and compression portions 152, as best seen in FIG. 2A, provided with rigid plastic sleeves 154 that provide lubrication between the inner walls of the loading chambers and the outer surfaces of the loading and squeezing portions 152 to prevent them from seizing or jamming. Exemplary materials for forming plastic sheaths 154 are polyetheretherketone (PEEK) manufactured by ICI America and RTP Co.

Each of the loading and squeezing parts 152 is connected via a control rod 15 to a retractable drive shaft of the hub, for example, a hydraulic piston 157 or the like that controls its cyclic movement between the retracted position and the extended position. Tobacco batches are fed to the feed lines 110 through feed openings 158 formed in their upper wall. In particular, the loading apertures 158 extend over the entire width of the loading ducts 10 and are positioned between the withdrawn position of the loading and compression portions 52 and their extended position. These rotary closure members 160 are associated with these loading apertures 160 and are capable of pushing the tobacco dose 150 into the loading chamber as they move into the closed position shown in FIG. 2 dashed lines. In particular, a pair of barrier members 162 are used to separate the loading chamber from the impregnation device, which may also be nail-closing members. The latching members 162 are movably mounted between a first position in which their latching members are located from the outside of the loading ducts 110 and a second latching position in which the working nails are inserted into the loading ducts 110 and thereby prevent further progress within the loading ducts. 0, however, if the closure part is closed.

To feed the tobacco batches 150 into the spool unit 16, the tobacco batches 150 are discharged from the rotary shut-off member 140 in the form of a rotary valve through the feed aperture 158 into the feed line 110. The shutters 162 are inserted into these feed lines 110 and the rotary shutter 160 is rotated downwardly to cover the loading opening 158, and in this closing movement, if necessary, squeezes the tobacco dose 150 within the loading lines 110, if necessary.

The semi-cylindrical loading and compression parts 152 then begin to move to their extended position. Tobacco batches 150 are moved horizontally through the inner space of the loading ducts 110 by the loading and squeezing portions 152 and are pressed into the annular space at the periphery of the spool unit 16. The opposing half-roller loading and squeezing portions 152 cooperate with each other to form a cylindrical joint. a shell around the tie rod 20 of the spool unit 16, therefore, the compressed tobacco is held on the tie rod 20 of the spool unit 16 during its movement to the impregnation position, which will be described in the next section. The cylindrical shell assembled from a pair of semi-cylindrical loading and compression members 152 may also be delimited in part by one frame member or a pair of frame members (not shown) that may be positioned above and / or below the axis of the spool unit 16. Such frame members are preferably adapted to flush with semicircular edges

Μ loading and compression parts 152 to form a closed cylindrical space around the compressed tobacco.

The loaded coil unit 16 moves to its impregnation position as shown in FIG. 1 and 8, and the sealing rings 30 on both ends of the coil unit 16 are

Ί pushed radially outwardly by the hydraulic fluid supplied by the supply line 32 to seal the pressure impregnation chamber 22 against leakage of substances from its interior. The sealing rings 30 are preferably joined by vulcanization or otherwise glued into annular grooves formed on the periphery of the end pieces 18 of the spool unit 16. At the interface between each of the elastomeric sealing rings 30 and the fluid supply line 32, a deformable plate or deformable strip 153 is disposed to the strips 30 were not glued to the bottom of the annular grooves at the outlets of the supply line 32. therefore, this deformable cover strip 153 can be pushed outward when the fluid is supplied.

In the annular grooves formed in the peripheral surface of each end portion 18 of the coil unit 16, annular elements 16 '', which may be abrasion-resistant rings or wiper rings, are fixed and are disposed in the axial direction immediately adjacent at least one face of each of The wear-resistant rings have a circumference larger than each of the cylindrical end pieces 18 of the coil unit 16, in which the annular space or gap between the coil unit 16 and the cylindrical shell 14 narrows. By narrowing this gap, elastomeric or elastomeric sealing rings 30 axial guidance during the time interval for sealing the joints. This limited destructive deformation of the sealing rings 30 leads to "overflow or extrusion" | the peripheral edges of the sealing rings 30 into the annular space between the cylindrical end portions 18 of the coil unit 16 and the cylindrical shell 14.

Preferably, each of the sealing rings of the end face of the annular surface at the periphery of the end is attached to the abrasion-resistant lid 160 'and the parts 18 of the coil unit 16 '

In a preferred embodiment, each abrasion-resistant ring is disposed adjacent the two end faces of the elastomeric sealing rings 30 and is welded, glued, and the like thereto.

Abrasion can be attached fastened. Elements resistant to the sealing rings 30 by the vulcanization process

Fig. 8 illustrates such a preferred embodiment of the passage design allowing interconnection of gas lines 38, 40 for supplying high pressure gas through the interior of the cylindrical shell 14 to ensure very rapid delivery of the expansion agent. An array of apertures 42 is formed around the periphery of the cylindrical shell 14. The increased cross-sectional area of the passage provided by the apertures 42 forming the group provides increased velocity of supplying and discharging the high pressure fluid into and out of the pressure impregnation chamber 22. position. Preferably, the apertures 42 are oriented diagonally and taper into narrower aperture sections 43 of smaller diameters, as shown in FIG. 8 and 8A to prevent tobacco caps from entering the passages during the movement of the bobbin unit 16 from one position to another.

The outer distributor ring 45 surrounds the cylindrical shell 14 and forms an annular space 44 around the apertures 42 distributed around the circumference of the cylindrical shell 14. The apertures 42 open into an annular groove 162 'in the end portions 18 of the coil unit 16 which is interconnected by radial ducts and metal. 164 and axial channels 166 with grooves 170 formed in the surface of the connecting rod 20. The high pressure fluid that has been supplied through the gas line 38 flows through the openings 42 into the channels 164, 166 until it reaches the longitudinal grooves 170. In these longitudinal grooves 170 the fluid comes into contact with tobacco loaded and compressed by the tie rod 20 of the spool unit 16, flows from the longitudinal channels 170 and enters the tobacco as shown by the arrows in FIG. The connecting rod 20 is surrounded by at least one mesh (not shown) to prevent clogging of the longitudinal grooves 170 by tobacco.

Fig. 10, 11, and 12 show alternative exemplary embodiments of the impregnator efficiency device with the coil unit housed in the shell, increasing the rate of delivery of the high pressure gaseous expansion agent to the annular high pressure impregnation zone, and extracting the expansion agent from the impregnation zone. As shown in FIG. 10 and 12, the device according to this particular embodiment is shown with the coil outlet body 16 in motion between its position. Thus, the coil unit 16 at the loading position and the impregnator is shown partially in and out of the cylindrical shell 14. In this exemplary embodiment of the device according to the invention, the apertures 42 passing through the cylindrical shell 14 are formed in the form of slots with an elongated cross-sectional shape which is particularly close to the cross-sectional shape of the valves 46, 48 in the gas lines 38, 40. impregnation mechanism and out of it. This achieves a reduction in the frictional interaction between the orifices and the expansion agent and the resulting effect based on a greater transport rate of the expansion agent at the entry and exit of the impregnation device.

Since the elongate openings 42 have a diameter larger than the particle size of the tobacco, e.g., tobacco cut filler, the exemplary embodiment of the apparatus of the invention shown in FIG. 10 to 12, the passage blocking member 260 best visible from FIG. 11 and which prevents or at least limits tobacco entry into f

elongate holes 42. The passage blocking member 260 is formed by an elongate body provided with an outer surface 262 having a greater width than the diameter of the holes 42. As best seen in FIG. 11 and 12, the locking member 260 is connected in the longitudinal direction between the circumferential portions of the end portions 18 of the bobbin 16 and is positioned in a radial direction opposite the apertures 42 passing through the cylindrical shell 14, as shown in FIG. 11th

As shown in FIG. 11, the locking members 260 extend across the portion of the tie rod 20 of the bobbin unit 16, which in turn forms the inner wall of the "chamber" on the bobbin unit 16. However, when this portion of the spool unit 16 passes through the cylindrical shell 14, the blocking members 260 cover the apertures 42 passing through the cylindrical shell 14, so that the tobacco present in the spool chamber is prevented from accessing the elongate holes 42. As best seen in FIG. 11 and 12, the outer surface of the locking member 260 is preferably curved, and its curvature corresponds to the shape of the inner surface of the cylindrical shell 14. The lower portion of the locking member 260 is preferably tapered to minimize tobacco storage space.

In a preferred embodiment of this part of the device according to the invention, at least two elongate holes 452 are formed in the cylindrical shell 14 and a corresponding number of locking members 260 are formed on the spool unit 16, as can be seen from the drawings. A spacer ring 45 is disposed around the outside of the cylindrical shell 14, defining an annular space 44 interconnecting the two apertures 42. therefore, the expansion agent supplied through the inlet aperture 38 'in the manifold piece 45 can enter the coil space through both groups of apertures 42 in the cylindrical shell. 14 simultaneously. Similarly, the discharged expansion agent may be discharged through all orifices 42 in the cylindrical shell 14 and through the orifice 40 'in the manifold 45.

Also, this measure increases the rate of supply and withdrawal of the expansion agent from the impregnation device formed by the coil unit 16 and the cylindrical shell 14, thereby allowing the length of one cycle to be reduced.

Again, as shown in FIG. 1, in a further operation following the introduction of the expansion agent into the impregnation device, the compressed and impregnated tobacco is maintained for a short period of time ranging from 1-2 seconds to about 20 seconds, under impregnation conditions, then the pressure is reduced. The pressure reduction should be practically instantaneous, that is to say, within a period of one second. This can be achieved in part by using a quick acting valve having a large cross-section of the through hole for rapid gas discharge and pressure reduction. In a preferred embodiment, the device is provided with a pressure sensor (not shown) located within the impregnation device for sensing the pressure and initiating the discharge of fluid from the sealing rings 30 on the coil unit 16, but when the internal pressure reaches a predetermined value above ambient. pressure and is, for example, equal to 352 kPa. The pressure of the hydraulic fluid in the supply line 32 supplying the sealing rings 3.0 is sensed by a second pressure sensor. Before the pressure drops to atmospheric pressure, for example at a pressure of about 350 kPa, the transducer actuates the hydraulic piston connected to the shaft 28 to control the movement of the spool unit 16. The spool unit 16 is then substantially immediately moved to the unloading position 26., therefore, tobacco expansion can begin.

A pneumatic discharge device is provided in the tobacco removal zone, such as an oil-free discharge compressor, not shown, which directs a fluid, such as high pressure air or nitrogen, to the tobacco layer surrounding the spool unit 16 as the spool unit 16 moves into of the unloading position 26 and out of it. The expanded tobacco collected in the unloading position 26 expands almost immediately and is shown in FIG. 1 to a regeneration hopper 172 and then to a conveyor device 174, for example, to a screw conveyor or the like. Preferably, the tobacco having a significant moisture content, for example greater than 13 percent by weight, is conveyed to the drying zone 176 by means of a conveying device 174.

As can be better seen from FIG. 9, expanded tobacco is fed to a drying line 178 in a drying zone in which it is entrained by heated air moving upwards. The heated air preferably has a temperature of less than about 177 ° C, in particular a temperature in the range of 93 ° C to 149 ° C. The tobacco is conveyed through the drying zone at a temperature and for a time sufficient to reduce the moisture to less than 13 percent by weight, in particular to a humidity between 6 and 12 percent by weight. The dried expanded tobacco is then fed to a separation zone 180 where the fluids, including the expansion agent, pass through a screen 182, or other separation means, such as a cyclone separator, and are transferred to a regeneration loop 184.

The gas passing through the regeneration loop 184 is primarily composed of nitrogen or other inert gas that is injected into the regeneration loop 184 in the injection zone 186 for injecting the gas. The nitrogen is heated in the heater 18 8, passes through the fan 190 and then continues to move the regeneration loop 184 to the tobacco inlet point. Extraction stream 192 is continuously discharged from regeneration loop 184 and transferred to a thermal oxidation zone in which propane in nitrogen is combusted.

F

The tobacco then passes from the separation zone 180 to the gas interruption rotary valves 194, 196 and is then recovered in the regeneration zone 198. The two rotary valves 194, 196 prevent any quantity of propane from outside from entering the regeneration zone 198. For reliable assurance This function therefore also supplies an inert gas, for example nitrogen, between the two rotary valves 194, 196. As shown in FIG. 2, nitrogen may also be fed to other areas of the system for similar reasons. In this connection, a security jacket 200, shown in FIG. 2 dashed lines. This safety jacket 200 is adapted to recover any amount of propane escaping from the system during operation. Nitrogen is continuously supplied to various places in the system. Propane escaping through various leaks of the system is recovered within the containment jacket 200 and is fed to the thermal oxidizer for combustion.

Although using propane or a similar gas as an expansion agent or an expansion agent of the type described in US-PS 4,531,529 (White and Conrad), it is not necessary to heat the tobacco to achieve fixation of the tobacco in expanded form. High humidity can expand to a higher degree than tobacco with normal humidity. However, it has also been found that some or all of the increased volumes may be lost because tobacco that is too moist may collapse. However, the drying carried out by the process according to the invention, as determined by the tests, retains an increased volume.

The drying process proceeds particularly rapidly and, for example, after increasing the tobacco volume, starts at less than 5 minutes after completion of the expansion, in particular at less than 1 minute after expansion. However, it is also possible to start drying the tobacco immediately after expansion. However, there is also such an exemplary embodiment in which heated nitrogen can be blown through the fan used to remove tobacco from the spool unit 16, if necessary, and the tobacco can be immediately transferred to a drying zone.

The effect of tobacco moisture on its expansion is shown in FIG. 13, which is a graph showing the extent of tobacco expansion at different humidity levels and different degrees of pre-heating of tobacco. In all cases, the tobacco was impregnated for 15 seconds with propane at a pressure of about 172.3 MPa and preheated to a temperature of about 149 ° C. Prior to expansion, the tobacco had a filling capacity of about 450 cm ² / 100g. As shown in FIG. 13, increasing the moisture content of the tobacco to a level of about 20 percent by weight greatly improved the expandability of the tobacco, especially when the tobacco was heated to a temperature of about 66 ° C or higher.

When propane is used as the impregnating fluid, the cumulative amount of heat supplied to the impregnation zone from the heated propane and preheated tobacco is preferably sufficient to create impregnation conditions in the impregnation zone, i.e. temperatures between 116 ° C and 132 ° C, especially about 127 ° C. It has been found that impregnation taking place at a temperature of about 127 ° C and a pressure of about 172.3 MPa can be carried out in a time of about 5 seconds or less if the heat is supplied by both preheated tobacco and preheated propane.

The degree of compression of the tobacco during the impregnation also affects the degree of volume increase. The tobacco is compressed at impregnation to a compression ratio of at least 1.5: 1. The compression ratio is the ratio of tobacco volume before and after compression. The volume of tobacco prior to squeezing or the loose volume is determined by measuring the density of tobacco in a cube container, all sides of which are one foot long, i.e. 30.5 cm long. The tobacco is poured into this cube container and weighed to determine the density of the loose tobacco. The volume of bulk loose tobacco before and after compression at the periphery of the spool unit 16 can be determined from the batch weight and bulk density of the bulk tobacco. The bulk of the bulk tobacco is then divided by the volume of the compressed tobacco batch, i.e. the volume of tobacco batch treated in the impregnation device, such as the coil unit 16, to determine the compression ratio. All values are measured at the actual humidity, or are adjusted to the actual humidity of the tobacco feed to the impregnation zone. Thus, for a spool 16 with an impregnation volume of 409.7 cm ^3, when tobacco compression, having in bulk volume of 819.3 cm ^3, the peripheral surface of the spool 1 6 should result in a compression ratio of 2: 1.

The tobacco is preferably compressed to a compression ratio greater than 2: 1, up to a ratio of 3: 1, or even greater. Compressing the tobacco increases its density, so the tobacco fed into the impregnation zone has a significantly greater density than the tobacco density before compression. It is known to those skilled in the art that the bulk density of the loose tobacco may vary within very wide limits depending on whether the tobacco is in leaf form or in the cut filler type of tobacco, the moisture content of the tobacco, and a variety of other factors. Tobacco with a packing density of 320 to 561 kg / m ³ , calculated for a moisture content of 12%, is used in the apparatus of the invention. Although increasing the density of the packaged tobacco may increase the cycle time to some extent to achieve consistent expansion, packaging densities of greater than 400 to 480kg / m ³ , and higher, calculated for a humidity of 12%, have also been successfully used in the present invention. impregnation of less than 20 seconds and the filling capacity increased by more than 50-100%.

In FIG. 14 is a graph showing the possibilities of varying the tobacco volume increase as a function of changes in tobacco densities during impregnation and at different impregnation times. This graph shows the impregnation of tobacco samples having a moisture content of 27% propane under the same conditions described above. The impregnation times varied from 4 seconds to 20 seconds. Tobacco samples having an initial bulk density of about 100 kg / m ³ at 12% humidity and at 24 ° C were compressed to 320, 400, 480 and 560 kg / m ³ (all densities were calculated or adjusted for humidity 12%). As shown in FIG. 14, the degree of expansion increases with increasing impregnation times and decreasing tobacco compression. However, excellent tobacco expansion is achieved even at high packaging densities and short impregnation times of about 10 seconds or less.

Fig. 15 illustrates the flexibility of the expansion process and apparatus of the invention. This graph is composed of a graph containing various expansion values and shows the total increase in tobacco volume per hour (in cubic meters per hour) that can be achieved in the apparatus of FIG. 1 as a function of impregnation times and tobacco compaction. These data assume that there is space for storing tobacco around 6.555 dm ³ and that the process proceeds continuously at the displayed cyclic time intervals. As shown in FIG. Obviously, it is possible to increase the amount of tobacco being processed by shortening cycle times and increasing tobacco compression. This is due to the increased amount of tobacco processing, notwithstanding the fact that the expansion of each batch of tobacco was not necessarily as great as could be achieved at lower densities and / or longer cycle times. Thus, the present invention provides a flexible tobacco processing method that allows varying the degree of tobacco expansion and the amount of tobacco being processed per unit of time.

The various aspects of the tobacco expansion processes described above have been mentioned in particular in connection with the use of propane as an expansion agent to promote tobacco expansion and the use of impregnation temperature conditions near or above supercritical temperatures together with conditions involving elevated pressure approaching or exceeding supercritical pressure, and in conjunction with the device of the invention. It is to be understood that the method and apparatus of the invention may be varied and not merely carried out in accordance with the exemplary embodiments described and illustrated. For example, if regeneration of the expansion agent, especially propane, is not desired, the expansion agent may be combusted in a subsequent use. In addition, the basic features of a method of inducing tobacco expansion and apparatuses for carrying out the method, although the most preferred field of use are expansion methods and apparatuses employing high density expansion agents at supercritical temperatures and employing short impregnation times. also in different variations of expansion processes using different expansion agents and different devices.

The tobacco filling capacity, considered in the context of this description, is measured by normal procedures using an electronic automatic filling capacity meter having a stiff spot of 92.1 mm diameter sliding in a cylinder of the same inner diameter and acting on the tobacco sample stored therein. in the cylinder at a pressure of 182.8 kPa for 5 seconds. These parameters should simulate the packaging conditions to which tobacco is exposed in a cigarette manufacturing facility during the formation of tobacco rods. Weighed 50g tobacco samples were used to test tobacco expansion. For unexpanded tobacco, samples weighing 100g were used.

The moisture content of the tobacco samples was measured by placing a stogram sample of tobacco in a wire mesh basket followed by placing the basket in a forced air oven in which the temperature was maintained at about 93 ° C for about two minutes. Tobacco was also weighed with a wire basket before and after heating in the furnace and the weight loss, expressed as a percentage of tobacco weight before and after heating, was considered to be moisture percentage.

The invention has been elucidated on the basis of the examples given, but many changes, variations and modifications can be made to the examples, without departing from the scope of the invention described in the foregoing and defined in the following claims.

Claims (42)

PATENT CLAIMS Apparatus for supplying heated tobacco to an impregnating zone, characterized in that it comprises a conveying line (68) for tobacco supply, a metering device (70) downstream of the conveying line (68) for metering batches of tobacco supplied to the impregnation zone, steam injectors (80) for injecting steam into the tobacco batches and devices for conveying the heated tobacco into the impregnation zone. Apparatus according to claim 1, characterized in that the device for conveying tobacco to the impregnation zone comprises a horizontally oriented pipe (110) provided with a feed opening (158) in its upper wall and adapted to supply tobacco to the impregnation zone. Apparatus according to claim 2, characterized in that the filling opening (158) in the horizontal conduit (110) is provided with a rotatable closing element (160) adapted to press tobacco into the horizontal conduit (110). Apparatus according to at least one of claims 1 to 3, characterized in that the steam injector (80) comprises steam guiding elements through a plurality of openings formed in at least one wall in contact with the tobacco batch. Apparatus according to at least one of claims 1 to 4, characterized in that the steam injector (80) comprises elements for injecting steam into the tobacco at a temperature sufficient to heat the tobacco to a temperature of at least 52 ° C. Apparatus according to at least one of claims 1 to 4, characterized in that the steam injector (80) comprises elements for injecting steam into the tobacco at a temperature sufficient to raise the temperature of the tobacco to at least 66 ° C. An apparatus for injecting tobacco into an impregnation zone, comprising a pair of opposed pipes (110), a spool unit (16) movable back between its first position, located between the open ends of the opposed pipes (110), and an impregnation position. located within the cylindrical pin of the pin body (14), the coil unit (16) comprising first and second disc members (18) and a connecting rod (20) connecting the two end portions (18) to each other between the inner sides and the surface a connecting rod (20) is formed around the connecting rod (20) an annular space, and a compression device for compressing tobacco, slidable in reciprocating movements within each conduit (110) between the withdrawn position and the extended tobacco transporting conduit (110) and its injection into the annular space on the coil unit (16). wherein the tobacco squeezer comprises in each case a squeezer (152) having a semi-cylindrical face, the size and shape of which are adapted to form a cooperating cylindrical surface around the annular space of the spool unit (16). Apparatus according to claim 7, characterized in that each pipe (110) is provided with an opening (158) about its upper wall for loading tobacco into the pipe (110) at a location between the withdrawn position and the extended position of the compression device and the pivotable element (160) for Also closing the opening (158) and injecting the tobacco into the pipe (110). Apparatus according to claim 7 or 8, characterized in that it comprises a steam injector (80) for injecting steam into the tobacco. F Device according to at least one of claims 7 to 9, characterized in that the spool unit (16) is provided with sealing elements adapted to form a seal between the cylindrical end portions (18) of the spool unit (16) and the inner surface of the cylindrical shell (14). when the coil unit (16) is in the operating position, wherein the pressure chamber is defined by the shell (14), the end portions (18) and the sealing elements, and inlet cylinders are formed in the cylindrical shell (14) to supply the working fluid to the pressure chamber; when the coil unit (16) is slid into the operating position, wherein the inlet elements have a total cross-sectional area sufficient to rapidly deliver the fluid to be treated into the chamber and a blocking device for trapping particles and restricting solid material entry into the inlet elements. Device according to claim 10, characterized in that the inlet elements comprise a plurality of openings (42) distributed around the circumference of the cylindrical shell (14), and the locking means comprise inlet portions (43) of the openings (42) having a smaller cross section than is a predetermined size for preventing particles from entering the apertures (42). Device according to claim 11, characterized in that the group of holes (42) passing through the cylindrical shell (14) is circumferentially surrounded by an outer annular space (44) for directing the working fluid evenly to all the holes (42) in the cylindrical shell (14). 14). Apparatus according to claim 10, characterized in that the inlet elements comprise at least one elongated opening (42) with an increased diameter substantially greater than the particle size of the cut tobacco filling, wherein the blocking elements for blocking the inlet of the tobacco particles comprise at least one an elongate locking member (262) having an outer surface (262) of greater width than the diameter of the at least one aperture (42) and the locking member (260) being inserted longitudinally between portions of the end portions (18) of the spool unit (16). Apparatus according to claim 13, characterized in that the locking member (262) is located radially opposite at least one elongated hole (42) of enlarged diameter. Apparatus according to claim 14, characterized in that at least two elongated openings (42) with an enlarged cross-section are formed in the cylindrical shell (14ä) and the outer side of said openings (42) is surrounded by an annular space (44) for conducting the working fluid. simultaneously through the at least two openings (42). Device according to at least one of claims 10 to 16 15, characterized in that the coil unit (16) is provided with an elastomeric sealing ring (30) disposed in an annular groove on the periphery of each end piece (18) by means for deforming the elastomeric sealing ring (30) radially outwardly for peripheral contact with the inner surface of the cylindrical shell (14) when the coil unit (16) is positioned in the impregnation position, in which the cylindrical shell (14), the end portions (18) of the coil unit (16) and the sealing means are formed after compression; one annular member (160 ') disposed on a peripheral portion of each cylindrical end piece (18) and having a perimeter larger than the end piece (18) and adjacent axially to at least one end face of the elastomeric sealing ring (30) disposed on the periphery of the end piece ( 18). Apparatus according to claim 16, characterized in that each of the elastomeric sealing rings (30) is connected to an axially adjacent prestressing element (160 '). Device according to claim 16 or 17, characterized in that each of the elastomeric sealing rings (30) is mounted in an annular circumferential groove formed on the periphery of the end piece (18) of the coil element (16). 19.. Device according to at least one of Claims 16 to 18, characterized in that one of the annular elements (160 ') is connected axially to each end face of the sealing rings (30) and is connected to the sealing ring (30). 20. A method of increasing the volume of tobacco, characterized in that a batch of tobacco having a predetermined pre-expansion moisture of greater than 13 percent by weight is placed in the impregnation chamber, the tobacco is impregnated in the impregnation chamber with an expansion agent, then tobacco is removed from the impregnation the chambers and the impregnated tobacco are subjected to conditions sufficient to increase the tobacco volume and produce expanded tobacco with a moisture content greater than 13 percent by weight, and finally the tobacco is dried to postexpansive moisture less than 13 percent by weight to maintain the tobacco expansion value resulting from . The method of claim 20, wherein the drying is carried out in a time interval of less than 5 minutes and prior to the subsequent tobacco start-up. 22. The method of claim 21, wherein the drying is carried out in a time interval of less than 1 minute and before the subsequent tobacco start-up. Method according to at least one of Claims 20 to 22, characterized in that the drying is carried out at a temperature of up to 177 ° C. The method of at least one of claims 20 to 24 23, characterized in that the tobacco coming out of the drying process has a moisture content greater than 6 percent by weight. A method according to at least one of claims 20 to 25 24, characterized in that tobacco with a moisture content of greater than about 20 weight percent is loaded into the impregnation chamber. The method of at least one of claims 20 to 24, characterized in that tobacco with a moisture content of greater than about 24 weight percent is loaded into the impregnation chamber. A method according to at least one of claims 20 to 27 26, characterized in that tobacco having a temperature above 66 ° C is placed in the impregnation chamber. Method according to at least one of claims 20 to 28 27, characterized in that the drying is carried out by applying a stream of heated gas to the expanded tobacco. The method of claim 28, wherein the gas stream is heated to a temperature between 93 ° C and 149 ° C. The method of claims 28 to 29, wherein the tobacco is conveyed through the drying zone by a stream of heated gas for a period of time sufficient to reduce moisture to 6 to 12 percent by weight. The method of claims 20 to 30, wherein in the impregnation operation, the tobacco is contacted with propane at a pressure greater than about 150 psig for a maximum of about 15 seconds. T The method of claims 20 to 31, wherein the propane used to treat the tobacco placed in the impregnation chamber is preheated to a temperature greater than 132 ° C. 33. The method of claim 32, wherein the sum of heat supplied to the tobacco in the impregnation chamber from heated propane and preheated tobacco is sufficient to provide impregnation conditions in the impregnation zone at temperatures between 116 ° C and 132 ° C. . The method of at least one of claims 20 to 34 33, characterized in that the tobacco stored in the impregnation chamber is compressed in a compression ratio of at least 1.5: 1. 35. The method of claim 34, wherein the tobacco stored in the impregnation chamber is compressed in a compression ratio of about 2: 1. 36. The method of claim 34, wherein the tobacco stored in the impregnation chamber is compressed in a compression ratio of at least 3: 1. An accumulator for rapidly delivering an expansion fluid having a density equal to or approaching the density of a fluid, comprising a pressure vessel (56) containing the expansion fluid and a gaseous pressurizing agent within a single and a non-divided chamber, the pressure vessel (56) comprising a first zone (62) and a second zone (64) adapted to separately maintain the fluids under pressure conditions and to maintain the fluids at or near the critical temperature of the expansion agent. 38. The accumulator of claim 37, wherein the container (56) further comprises a third zone interconnected with both the first fluid zone (62) and the second fluid zone (64) to maintain the fluid barrier at the point of contact of the two fluids in the fluid. a first zone (62) and a second zone (64). 39. The accumulator of claim 37, wherein the third zone comprises a movable separating fluid layer separating the expansion agent from the compression fluid within the pressure vessel (56). The accumulator according to at least one of claims 37 to 39, characterized in that the pressurizing gas is nitrogen and the expansion agent is propane. 41. The accumulator of claim 39 or 40, wherein the partitioning fluid is water. Battery according to at least one of Claims 38 to 41, characterized in that the container (56) is maintained at a pressure of more than 172.3 MPa and at a temperature of greater than 93 ° C,