FI103635B - Method and apparatus for expanding tobacco - Google Patents

Description

103635

Method and apparatus for expanding tobacco. - Tobaksexpansions-. förfarande och -anordning.

The invention relates to methods and apparatus for expanding tobacco 5. More particularly, the invention relates to methods and apparatus for improving the production and economy of expanded tobacco.

Over the past two decades, tobacco-blowing methods have become an important part of the cigarette making process. Tobacco expansion methods are used to restore the bulk density (bulk density) and / or volume of tobacco lost during drying and storage of the tobacco leaf. In addition, expanded tobacco is an important component of many low health and very low health cigarettes.

U.S. Patent No. 3,524,451 to Fredrickson; and U.S. Patent No. 3,524,452 to Moser et al. describes methods of contacting a tobacco with an impregnating agent and then heating it rapidly to evaporate the impregnating agent and expand the tobacco. U.S. Patent No. 3,683,937 to Fredrickson et al. impregnation of the tobacco followed by either heating or rapid pressure reduction to expand the tobacco.

The use of carbon dioxide to expand tobacco has been described e.g. U.S. Patent No. 4,235,250 to Utsch; U.S. Patent No. 30,2258,729 to Burde et al .; and U.S. Patent No. 4,336,814,

Sykes et al. In these and related methods, carbon dioxide, either in the form of gas or liquid, is contacted with the tobacco to impregnate it and the impregnated tobacco is subjected to a rapid heating condition for expansion. In the known carbon dioxide expansion processes, it is typically necessary to overheat the tobacco in order to achieve a substantial and stable expansion. This overheating may adversely affect the taste of the tobacco and / or form excessive fine powder. In addition, methods that use liquid carbon dioxide to impregnate tobacco typically result in impregnated tobacco in the form of solid tobacco pieces containing carbonic acid ice which must be decomposed before heat treatment, thereby increasing the complexity of the method.

10 U.S. Patent No. 4,388,932 to Merritt et al., Describes a process for reconstituting previously expanded tobacco! post-reordering to increase fill capacity.

Previously expanded tobacco with an OV content of less than 6% ('Door Volatiles') is heated to reduce its OV content to a value well below 3%. The OV content of tobacco is said to be approximately equivalent to its moisture content since less than 0.9% by weight of the tobacco contains volatile substances other than water. The OV 20-delta very low tobacco recovered from the post-expansion heating step is subjected to the rebuilding step to increase its moisture content and is said to weigh less during the rebuilding step than if it were not heat-treated * * i · ·· ····· after expansion. It was proposed to strengthen tobacco during heat treatment to explain the increased stability of expanded tobacco during tobacco reorganization.

30, U.S. Patent No. 4,531,529 to White and Conrad describes a method for increasing tobacco fill capacity, wherein the tobacco is impregnated with a low boiling and high volatile blowing agent, such as a normally gaseous halogen or or near it. The pressure is rapidly released to atmospheric pressure so that the tobacco expands without the need for a 3 103635 defrost step to either expand the tobacco or attach the tobacco to the expanded space. The pressure conditions of this method start at 36 kg / cm 2 (512 psi) and higher without a known upper limit. A pressure of less than 142 kg / cm 2 (2000 psi) was used to form a satisfactory puff of tobacco without excessive cracking.

EP-0404475 discloses a method for treating tobacco based on the use of a pressurized medium to alter the chemical and / or physical properties of the tobacco. FI-85094 is directed to a device for expanding tobacco using carbon dioxide as the expanding agent.

Conrad and White, U.S. Patent No. 4,554,932, disclose a fluid pressure processing device comprising a cylindrical tubular jacket and a bobbin assembly mounted to move reciprocally between the outer jacket loading station and the inner jacket handling station. When the spool is within the shell 20 in the cylindrical ends of the spool held in the annular grooves deformable sealing rings are forced radially outwardly tandemly-engagement with the inner side of the PAI to form a chamber therebetween inside the shell between the spool ends. The channels are arranged to introduce the treatment medium 25 into an annular pressure chamber formed inside the jacket. The use of this device to impregnate high pressure tobacco with an expanding agent allows for easy loading and unloading of the tobacco and avoids the closing and opening problems associated with conventional sealing and locking mechanisms such as reversible autoclave lids.

This pressure vessel saves time and improves economy. . added to the expansion of tobacco.

The tobacco expansion method, including those described above and the 35 others, must be performed in batch processing using impregnation pressures substantially above atmospheric pressure. Batch processing processes require complex handling equipment and long cycle times due to the time required to open and close the containers and introduce and remove the impermeable agent from the containers. Some improvements in production have been made by modifying various devices used to reduce cycle time; however, significant production improvements in known batch processing systems are obtainable in accordance with conventional techniques, mainly by increasing the volume of individual systems and / or by increasing the number of simultaneous batch processing systems.

The present invention provides methods for expanding tobacco and a device that can be used to expand tobacco at rapid production rates utilizing high pressure tobacco impregnation conditions. The methods and apparatus include tobacco impregnation and expansion cycles of less than 20 to 30 seconds; the use of a preheated pressurized pressurizing agent such as propane; preheating the batches of tobacco; and / or compressing the tobacco in the high pressure impregnation zone to significantly improve the use of the space available in the high pressure impregnation vessel.

In order to achieve the objects of the invention, the apparatus for distributing heated tobacco according to the invention is characterized by the elements set forth in the characterizing part of claim 1.

The device for compressing tobacco into the impregnation zone according to the invention is characterized by the features set forth in the characterizing part of claim 7. The method disclosed in the preamble of claim 9 according to the invention is in turn characterized by the features set forth in the characterizing part of claim 9.

In one aspect, the present invention substantially improves the amount of tobacco filling capacity increase in tobacco expansion processes using high pressure impregnation conditions. In other aspects, the present invention provides fast batch feeding systems for reliably and economically feeding pre-sized batches of tobacco to the impregnation zone and for rapid and economical preheating of the batches of tobacco. The invention also provides hardware improvements to a high speed / high pressure, spool and diaper 5 type tobacco impregnator. Still further, the invention provides an improved pressure accumulator device for the rapid development and delivery of high temperature / high pressure impregnation gases which include flammable gas such as propane. The improved pressure accumulator not only minimizes the mass of any gas in the system at any given time, but also eliminates the expensive and problematic moving parts required in prior art pressure accumulators.

A substantial improvement in the tobacco filling capacity increase is achieved by impregnating the high moisture content of the tobacco with a blowing agent in a high pressure tobacco impregnation zone, expanding the impregnated tobacco under conditions which give expanded tobacco, which also has a high degree of dryness. Preferably, the drying of the expanded tobacco is carried out for a short period of time following the expansion, for example, less than about 5 minutes after the expansion. Although the extremely high moisture content of the tobacco fed to the high pressure impregnation zone may cause the tobacco to squeeze following the expansion process, which does not use heating for the expansion, it has been found that the fill capacity increases with the increased humidity up to about 30% . Preferably, the drying treatment is carried out at a temperature of 350 ° F (177 ° C) or less and does not reduce the moisture content of the tobacco to less than about 6-8% by weight so that volatile flavors are not removed from the tobacco.

Preferably, the tobacco introduced into the impregnation zone has a moisture content of greater than about 20% by weight, and 1 n 7 7 7 '

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preferably, it is greater than about 24% by weight to provide a substantial increase in the amount of puffing tobacco. Preferably, high moisture tobacco is preheated to a temperature above about 150 ° F (66 ° C) prior to impregnation. Drying following the expansion of the tobacco maintains a high filling capacity of the expanded tobacco.

In yet another aspect, rapid feeding and pre-shaping of batches of tobacco for impregnation of tobacco and subsequent expansion thereof is achieved. The device formed according to this aspect comprises a substantially vertical measuring tube for forming a vertical tobacco pillar. The tobacco pill dispenser, which is preferably a member having a plurality of spikes / pivots, is connected to the measuring tube and is selectively engageable with the tobacco pill to divide the pillar into and above the dispenser and to the lower portion below the dispenser. The blocking member disposed on the underside of the dispensing means is engageable with the tobacco pillar to support the tobacco pillar when the dispensing means is disengaged with the pillar. The barrier means is removable from the tobacco pillar such that, when the dispensing means engages the tobacco cap, the release of the barrier means results in the lower portion of the tobacco bar being released from the measuring tube. This tobacco is then fed in batches into the impregnation zone. The size of the batch of tobacco can be easily adjusted by varying the space between the dispensing means and the blocking member. 1 2 3 4 5 6

In yet another aspect, the vertical measuring tube 2 is used to pre-heat the tobacco fed into the impregnation zone. According to this aspect, the steam jet 4 is applied to the measuring tube at a point 5 on the upper part of the tobacco column to heat the tobacco to a high temperature, 6 preferably between about 100 ° F (38 ° C) and about 212 ° F (100 ° C) and heated tobacco is then fed into the impregnation zone. Preference is given to using the fast feeding and pre-measuring system described above to produce a preheated 1/1 Λ ”, / 7 f η to deliver the tobacco in a batch to the impregnation zone.

The preheating of the tobacco according to this aspect is rapid because the vapor is rapidly distributed through the tobacco. Further, the tobacco above the vapor spray zone is lost by rising steam and further acts as an insulator for the tobacco in the vapor spray zone so that heating costs can be minimized.

The vertical measuring tube is preferably disposed above an opening in the top wall of the horizontal feeding tube 10, which is arranged for feeding batches of tobacco into a high pressure impregnation device. A reciprocating compression member is mounted in the conduit to transfer tobacco through the conduit and to compress the tobacco 15 in a high pressure processing device downstream of the conduit. The opening in the tube, which is in communication with the measuring tube, is provided with a pivotable closing member capable of being compressed into the tobacco tube. This allows the tobacco and batch volumes of different densities to be fed into the impregnation zone without the need to change or modify the feeder.

The invention also provides improvements to the spool and diaper device of U.S. Patent No. 4,554,932 to Conrad and White to provide improved durability and speed. When used in preferred embodiments of the present invention, the bobbin and diaphragm device are operated at a cycle speed of 4 to 5 times per minute or faster. Thus, the high pressure 30 bobbin and diaper device is preferably cycled from 3,000 to 3,600 cycles or more per 12 hour day.

•: Although this device improves the speed and economy of tobacco expansion, it has been found that repeated outward expansion of elastomeric sealing rings on cylindrical end members under high temperature and high pressure conditions may cause premature failure of the sealing rings.

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The function and life of the sealing rings are improved by reducing the radial gap between the bobbin member and the inner surface of the tubular sheath at one or more locations axially adjacent to the sealing rings. This is preferably achieved by forming at least one circumferentially extended wear ring at each cylindrical end member at a position axially adjacent and in contact with at least a portion of the axial end face of the elastomeric sealing ring. Preferred la-10 extended wear rings are disposed in contact with each axial end surface of each elastomeric sealing ring. Because the wear ring has a larger circumference than the circumference of the bobbin end members, in order to prevent the bobbin from scratching the diaper, the shaft gap between the bobbin and the diaper adjacent the wear members is reduced. Placing elastomeric sealing rings adjacent to the wear rings provides improved axial support for the sealing ring when these rings are forced radially outwards at high pressures. This in turn minimizes the destruction of the peripheral parts of the sealing rings by receiving axial deformation.

In yet another aspect, the efficiency of the bobbin and diaper impregnation device is improved by increasing the inlet and outlet pressure of the high pressure gaseous blowing agent into and out of the annular high pressure impregnation zone. This is achieved by expanding the size of the gas inlet and outlet ports a female cross-sectional area, the gates communicating with the outside and inside of the jacket, while incorporating particle-preventing means to minimize tobacco entry into the gates.

In one embodiment of this aspect, the high pressure gases are discharged into and discharged from the cylindrical sheath through a plurality of cooperating ports through the sheath circumferentially distributed around the cylindrical sheath. An external manifold element surrounds the gates including a treatment medium that is allowed to pass through the peripheral gates to the 9 10 o 6 3 5 sheath. The diameter of each gate inside the sheath is smaller than a predetermined size to prevent tobacco from entering the gates.

In an alternative embodiment, at least one enlarged port having a substantially larger diameter than the tobacco particles is provided through the sheath. An elongate barrier means having an outer surface which is wider than the diameter of the gate engages longitudinally the peripheral portions of the spool end members and is radially aligned with the gate opening. When polishing the chamber portion, i. the portion between the end members being moved through the jacket, the barrier means covering the gate such that tobacco in the bobbin chamber is prevented from entering the enlarged gate. Preferably, at least two expanded ports are formed through the jacket and a corresponding number of barrier means are provided in Poland.

In another aspect, improved high pressure pressure batteries are provided for developing and storing batches of high temperature, high pressure gaseous blowing agent, preferably propane, at a temperature of about 250 ° F (121 ° C) and at a pressure greater than about 2500 psig. Previously, the introduction of batches of high pressure and high temperature propane into the impregnation zone at a cycle rate of 4 to 5 times per minute or faster has required either the storage of very high volumes of high pressure, high temperature propane; or the use of a pressure accumulator in the form of a pressure vessel having chambers separated by a motion-30 image member. An inert pressurizing gas was held in one chamber and propane stored in another. When propane was periodically added to and removed from the vessel, the movable member moved inside the vessel but was prone to failure.

The present pressure accumulators use a high pressure vessel containing both the blowing agent 35 103635 10 and the gaseous pressurizing medium inside the vessel but without a separating member between the blowing agent and the pressurizing medium. In one embodiment, the vessel is maintained at a temperature above both the critical temperature of the pressurizing medium 5 and the blowing agent and at a sufficiently high pressure such that the pressurizing agent and the blowing agent have a high density close to the density of the fluid. The pressurizing medium is selected such that its diffusion properties with respect to the blowing agent are such that the two materials can be kept in contact at very low mass transfer levels due to the diffusion between the two agents under in-vessel conditions. Preferably, the pressurizing gas is nitrogen and the blowing agent is propane. At pressures above 2500 psig and at temperatures above about 200 ° F (93 ° C), the two gases can be kept substantially separate in the vessel such that propane can be added to the vessel periodically and removed from the vessel with very low nitrogen loss to 20 kilos of propane.

In another embodiment of the pressure accumulator, the blowing agent and the gaseous pressurizing medium are contained in a high pressure vessel containing the first and second belt regions arranged separately to maintain the two media at or near supercritical temperature and the first zone; with the second zone to maintain the blocking medium: between the media in the first and second zones. The barrier medium, which may be water, prevents a substantial mass transfer between the pressurizing medium and the pressurizing medium. 1

In the drawings which form part of the original description of the invention: 103635 11

Fig. 1 is a schematic cross-sectional view of a preferred impregnation device used in the invention with various operating positions partially shown in dashed lines;

Fig. 1A is a schematic cross-sectional view of a pressure accumulator which may advantageously be used in conjunction with the apparatus of Fig. 1 for rapidly feeding a high temperature, high pressure impregnating agent thereto, including first and second zones arranged to hold two media separately at temperature and pressure supercritical 15 or above, and in zone medium communication with both the first and second zones to maintain the barrier medium between the fluids in the first and second zones; 20

Figure 2 is a cross-sectional view of a preferred tobacco delivery and loading device including a pair of vertical measuring tubes arranged to supply a pair of horizontal tubes upstream of the impregnation device of Figure 1;

Fig. 2A is an enlarged cross-sectional view of one end of a reciprocating tobacco compression member connected to a horizontal conduit in the tobacco dispenser of Fig. 2;

Fig. 3 is an enlarged cross-sectional view taken along line 3-3 of Fig. 2 and showing a preferred embodiment of a steam injection apparatus associated with measuring tubes in the apparatus of Fig. 2 12 105635 for introducing vapor into a tobacco pill;

Fig. 4 is an enlarged cross-sectional view taken along line 4-4 of Fig. 2 and showing a different preferred embodiment of the steam injection device in relation to the dispensing tubes in the device of Fig. 2; Fig. 5 is an enlarged cross-sectional view taken along line 5-5 of Fig. 2 and showing an embodiment of a preferred tobacco column dispenser associated with measuring tubes in the device of Fig. 2; 15

Fig. 6 is a partial front view, taken with parts thereof, taken along line 6-6 of Fig. 5, showing the lower portion of the dispensing tube of the device of Fig. 2 and showing a plurality of ridges associated with the tobacco piston assembly of Fig. 5;

Fig. 7 is an enlarged schematic cross-sectional view of a portion of the dispenser of Fig. 2 showing a vapor injector, a tobacco pillar dividing means, and a barrier means for delivering a predetermined tobacco volume to the impregnation expansion device of Fig. 1; Fig. 8 is a cross-sectional view of one end portion of the bobbin and diaper device of Fig. 1 showing sealing and abrasion rings associated with bobbin end members, also showing a plurality of circumferentially gated ports through the diaper wall 35 for introducing treatment medium; 13 10οόό5

Figure 8Α is a greatly enlarged cross-sectional view of a portion of the device shown in Figure 8 showing a preferred cross-section for individual gates through the shell wall; 5

Figure 9 is a schematic cross-sectional view of the tobacco drying loop used downstream of the impregnating device of Figure 1; Fig. 10 is a partial cross-sectional view of an alternative medium inlet arrangement for the bobbin and diaper device of Fig. 1, with the bobbin in motion between its loading position and its impregnation station, with enlarged gates disposed through the jacket, and with; Fig. 11 is a cross-sectional view taken along line 11-11 of Fig. 10 showing how gate blocking means, in Poland, plug gates extending through the sheath as the spool moves through the sheath; Fig. 12 is an enlarged perspective view of one of the elongate blocking members removed from the device of Figs. 10 and 11;

Fig. 13 is a diagram showing the expansion of tobacco with different amounts of moisture and different amounts of tobacco preheating;

Fig. 14 is a diagram illustrating how tobacco swelling may vary during impregnation with different tobacco densities and with different impregnation times; and 103635 14

Fig. 15 is a diagram derived from a combination of different expansion data to show the flexibility of the expansion method and apparatus of the invention and illustrates the total increase in tobacco volume per 5 hours (cubic meters per hour) obtained from the device of Figure 1 as a function of impregnation time and tobacco compression.

The various methods and device embodiments of the invention 10 are described below. As the invention is described with reference to certain methods and devices, including those shown in the drawings, it is to be understood that the invention is not intended to be so limited. On the contrary, the invention includes numerous alternatives, modifications and equivalents, as will become apparent from the discussion of the foregoing description and the following detailed description.

Figure 1 schematically illustrates the preferred impregnation methods and apparatus of the invention, including a spool and jacket device substantially constructed in accordance with U.S. Patent No. 4,554,932, issued November 26, 1985 to Conrad, the entire disclosure of which is hereby incorporated by reference. . The various details described in the '932 patent are omitted here for brevity. However, the '932 patent may be referred to for such details.

As shown schematically in Figure 1, tobacco is preferably first handled in preparation zone 10 to increase its moisture content to more than about 16% by weight, preferably more than about 20% by weight. The tobacco with increased moisture content is then introduced into the feed zone 12, where the tobacco is heated, as depicted in more detail below, and then fed back and forth to a high pressure medium bobbin and diaper processing device.

15 103635

The high pressure medium spool and diaper processing device includes a pressure vessel defined by a cylindrical diaper or shell 14 and a bobbin assembly 16. The diaper 14 and bobbin assembly 16 may be made of any suitable material, including stainless steel and the like. The particular structure and size of the jacket and spool is sufficient to withstand the pressures that are encountered inside the pressure vessel, as is evident.

The bobbin assembly 16 includes cylindrical end members 18 and a connecting rod 20. When the bobbin 16 is inside the sheath 14, as shown in Figure 1, the end members 18 together with the connecting rod 20 and the sheath 14 define an annular space 22 having a predetermined space 15. , forming a closed pressure chamber or zone.

The bobbin assembly 16 is disposed horizontally and is arranged for reciprocating motion by a dashed charging station 24; a discharge station 26, also shown with dashed lines; and, in particular, among the impregnation station 20 shown in Fig. 1. The high-speed hydraulic piston or similar motor means (not shown) is axially secured through the shaft 28, shown in part in Figure 1, to move the bobbin between the three positions.

'25

The polish is applied with tobacco at position 24 as described in more detail below and then transferred to the impregnation station. At the impregnation station, the bobbin is sealed inside the jacket 14 by radial expansion of the elastomeric sealing rings held in the annular grooves formed on each end member of the bobbin 18. The construction of the elastomeric sealing rings 30 will be described in greater detail later in connection with FIG.

The sealing rings are formed of a deformable elastomeric material, such as vulcanized rubber, and are arranged to receive hydraulic fluid through hydraulic lines 32. Hydraulic fluid, for example food grade oil, is forced through conduits 32 by hydraulic pressure accumulator 34. Hydraulic fluid is forced through bore 5 through connecting rod 36, shown in part in Figure 1, connected to at least one end of spool 16. The hydraulic fluid is forced against the inside of the sealing rings 30, causing them to swell outward and seal the pressure chamber 22 against leaks.

10

The high pressure gas supply and discharge lines 38 and 40, respectively, are connected through the sheath 14 via a plurality of ports 42, which will be described in greater detail in connection with FIG. These gates, which may be circumferentially distributed around the circumference of the sheath 14, as shown in Fig. 8, or may have an enlarged cross-section as shown in Figs. 10, 11 and 12, allow high-pressure medium to enter and expel is impregnoin-20 in the position. The external manifold channel 44 surrounds the ports 42 and includes a treatment medium which is passed to the sheath 14 via the peripheral ports 42. The high pressure medium flows through the ports 42 and then into the tobacco which is loaded and pressed around the bobbin connecting rod 20 through a plurality of ports and channels in the bobbin body, shown in Figure 8 and described below.

A pair of fast acting valves 46 and 48 are provided to rapidly introduce and release the media into the impregnation chamber 22. Preferably, these valves are ball valves having a port size ranging from 0.5 inches to 1.5 inches in diameter or more, depending on the size of the impregnation zone 22, thereby providing substantially immediate entry and removal of the high pressure medium into the impregnation zone 22. The valves are opened 17 10ό635 and preferably closed by high-speed hydraulic actuators, not shown.

On the inlet side, the high pressure gas line 38 is coupled to the accumulator 50, which is described in more detail below. The heater 52 is arranged to heat the gas supplied to the pressure accumulator 50. The pressure accumulator 50 may also be heated by means not shown to maintain the medium in the accumulator in a heated state 10. The high pressure pump 54 is provided upstream of the heater 52 to supply the high pressure medium, e.g. at 2500 psig, to the heater 52 and the pressure accumulator 50. The line 40 used to remove the high pressure fluid from the impregnation zone 22

The pressure accumulator 50 is used to provide a high pressure imp-20 conditioning medium such as propane at 2500 psig to the impregnation zone in the bobbin winder indicated in Figure 1. The pressure accumulator 50 includes a tubular container 56 formed of a material capable of withstanding high temperatures and pressures. . The top and bottom of the pressure accumulator have apertures 58 and 60, respectively, to release high pressure gases.

An inert high pressure gas such as nitrogen, at a pressure greater than about 2500 psig, is allowed to pass through port 58, and due to pressure and temperature conditions in the reservoir, is substantially separated in the upper portion 62 while an expansion medium such as propane is passed through port 60 at elevated pressure, for example greater than about 2500 psig, at lower portion 64 of container 35. Container 56 is maintained at a temperature and pressure approaching or above the critical temperature and pressure of both the pressurizing medium and the expanding medium. Under these conditions, and with selected media, such as nitrogen pressurizing medium and propane blowing agent, the diffusion capacity of the gases in the two media zones 62 and 64, respectively, may be low enough to keep the two media substantially separate in the pressure medium 50.

When the blowing gas is removed from the pressure accumulator, the pressure drop 10 is detected by sensor means (not shown) and the controller activates a pump 54 which immediately begins to refill the pressure accumulator with a high pressure blowing agent, preferably propane. The pressure sensor can be arranged in a pressure accumulator or integrally inside the pump 54. The gas-15 pressure accumulator 50 is refilled in a short period of 5 to 30 seconds, the period used in the present invention to impregnate tobacco in the impregnation zone 22 of Figure 1.

As indicated by arrows 65 in Figure 1, the level of the blowing agent in the pressure accumulator 50 changes cyclically between a predetermined upper level and a predetermined lower level as it is added to and removed from the container. The lower level is selected to be at a certain predetermined distance '' 2'5 from the bottom of the container such that removal of the blowing agent does not remove the pressurizing medium. Thus, a lower level is selected to prevent the blowing agent from leaving near the interface of the two media. For propane and nitrogen gases, the lower level of the propane medium 3.0 may preferably be selected to be about 1 foot (about 305 mm), although different levels may be used depending upon the size of the tank and the conditions therein, as is self-evident.

The altitude control device, LC, may be used to assist the earth in maintaining the blowing agent, for example propane, within the 1 η λ (<7 r ί y / 't'UuO 19) level of the above predetermined limits. Preferably, the media interface level sensor or the like The integral or separate control system responds to a 5-level sensor and controls the release and removal of the pressurizing medium, such as nitrogen, into and out of the pressure accumulator, as required to maintain the blowing medium between the upper and lower predetermined levels.

Following removal of the blowing agent, a fresh portion of the blowing agent is pumped back into the pressure accumulator until a predetermined upper pressure is reached. The predetermined upper pressure is selected based on the following criteria: (1) the combined total volume of the conduits 38 between the pressure accumulator, the impregnation zone 22 and the pressure accumulator 50 15 and the impregnation zone 22; and (2) the desired pressure in the impregnoin zone. Because the pressure in the accumulator drops when gas is discharged to the gas conduits 38 and then to the impregnator impregnation zone 22 as a result of increasing the gas volume, the upper pressure must be sufficient to achieve the final pressure of the blowing agent at the predetermined pressure for tobacco impregnation. Thus, with a final pressure of about 2,500 psig, the upper pressure may be, for example,}}, 2,700-3,000 psig, depending on the factors mentioned above.

Typically, the pressurizing medium disappears over time due to absorption of the pressurizing medium into the blowing agent when in contact with the pressurizing medium when in the pressure accumulator. Although the low gas diffusion capacity ratio between the media in the pressure accumulator may theoretically allow them to remain substantially separated, even the extremely low gas diffusion capacity values for the two media in the pressure accumulator can result in 35 small pressurized media discharges with each blowing agent removal. However, the low level of absorption of 10ό6ό5 20 of 20 carcinogenic media has no substantially negative effect on the expansion of the tobacco.

When the system includes a recovery system, recovery of the blowing agent after filling typically results in the separation and removal of any absorbed pressurizing medium so that substantially pure blowing agent can be recovered for recycling. However, the absorbed pressurizing medium is typically not recovered, and furthermore, the presence of the absorbed pressurizing medium in the blowing agent typically reduces the amount of blowing agent that can be economically recovered after use. The amount of pressurizing medium absorbed by the blowing agent is an equilibrium amount determined based on the diffusion capacity values of the two media at temperature and pressure of the pressure accumulator 50 and pressure accumulators, and is preferably less than about 5% to 20% by weight.

Fig. 1A shows a pressure accumulator adapted to minimize absorption of the pressurizing medium by the blowing agent. This pressure accumulator 50 'employs a third and even' 2Ϊ denser medium, such as water, in the zone separating the pressurizing medium and the expanding medium as a moving fluid barrier layer between the two media. As shown in Figure 1A, the pressure accumulator 50 'includes a first zone 62' for receiving a pressurizing medium 3.0 such as nitrogen, and a second zone 64 'for receiving and separating the blowing agent under high temperature and pressure conditions. The third zone 61 is in fluid communication with both the first and second zones and includes a dense fluid such as water as a barrier medium between the media in the first and second zones.

i 21 10ό635

The barrier fluid medium shown in Fig. 1Α pressure accumulator minimizes or eliminates mixing of the pressurizing medium and the blowing agent even under conditions of increased turbulence.

This feature reduces the consumption of the pressurizing medium and subsequent loss of the blowing agent during its recovery, and may also simplify the structure of the blowing agent recovery system, since the separation of the absorbed medium is no longer essential. In a pressure accumulator of Figure 1A, a blowing agent, such as a pro-10 head, typically absorbs a small amount of a barrier medium, e.g., water.

Both water and nitrogen replenishment are fed to the pressure accumulator 50 'as shown in Fig. 1A, and separate interface 15 level detectors LC are preferably arranged in combination with integral or discrete control means to control the water and nitrogen discharged to the pressure accumulator. These guides respond to the surface level detectors and provide water addition at a sufficient rate and speed to maintain the total volume of water within the pressure accumulator within a predetermined upper and lower control limit. Additionally, the control means provide for addition and removal of nitrogen in response to altitude detector signals to maintain the height or position of the water-nitrogen interface within predetermined control limits.

In the pressure accumulator of Fig. 1A, the third zone 64 ', which contains the blowing agent substantially apart, is defined by a partially closed cylindrical chamber disposed at the top of the larger pressure vessel. This or similar arrangement is particularly advantageous in a preferred system that uses a barrier layer medium that is denser than either of the flowing pressurizers or expanders.

It will be understood that this structure and arrangement is merely a preferred construct and that other storage structures may be readily arranged to provide a movable barrier medium that separates the other flowable media within the container.

Figures 1 and 1A show preferred pressure accumulators according to the invention. However, other devices for providing a substantially immediate supply of a high pressure, high temperature blowing agent may also be used. For example, a container containing only a high density blowing agent maintained above the supercritical temperature may also be used. When the container contains a relatively large amount of blowing agent mass relative to the blowing agent mass removed in each cycle and maintains the high density of the blowing agent, removal of the blowing agent from the container can be achieved by a relatively small pressure drop in the blowing agent.

For example, at 2750 psig and 300 ° F (149 ° C), propane has a density of 23.76 lb / ft 3 (380 kg / m 3).

20 At the same temperature and pressure, 2,500 psig propane

density is 22.8 lb / ft3 (365 kg / m3). Thus, a one cubic foot (28 dm3) container of propane medium maintained at 2750 psig and 300 ° F (149 ° C) can remove 0.96 pounds (435 g) of propane at 300 ° F.

9 25 (149 ° C) into the impregnation zone with only slight pressure drop, m.p. from 2,750 psig to 2,500 psig.

In yet another embodiment of the invention, a mechanical pressure accumulator can be used to supply the blowing agent. One currently preferred mechanical pressure accumulator contemplated for use herein is a 'Metal Bellows' accumulator available from Parker Bertea Aerospace, Parker Hannfin Corp., Metal Bellows Division, 35 Moorpark, California.

Returning to Fig. 1, 23 105635 discharged into the impregnation zone 22

propane pressure is preferably greater than 2,000 psig, and more preferably between about 2,500 psig and 3,000 psig. In accordance with the present invention, it has been found that very short impregnation times, between about 5 and about 15 se-5 municipalities, can be used to impregnate tobacco at these high pressures while achieving a very favorable increase in tobacco filling capacity, for example over 50-100%. The temperature of propane is preferably maintained above 280 ° F (138 ° C), preferably in the range of about 300 ° F

(149 ° C) to 400 ° F (204 ° C), for example about 300-315 ° F (149-157 ° C). This provides extra sensible heat for heating the hair in the impregnation zone.

Referring now to Figure 2, there is illustrated a preferred tobacco upstream feeder and loading device. Tobacco in any number of shapes including leaf form (including stalk and veins), strips (stripped leaf), cigar-filler, cigarette filler (strips or shreds for making cigarettes) or the like, preferably cut filler tobacco, wetted by means known to a person skilled in the art, in block 66 a moisture content of at least about 13%, and preferably at least about 20%, and passed through a pneumatic conveying tube 68 to a measuring device generally designated 70. Preferably, as described, a measuring device 70 is formed by two separate measuring tubes 72 and 74. Preferably, '30 each measuring tube 72 and 74 has a substantially rectangular cross-section that increases or diverges slightly in the direction of the tobacco flow. As is evident, the measuring tubes may have other structures such as, for example, a circular cross-section.

35

The tobacco from the tube 68 is inserted into the inlet valve 76, which is located at the top of the measuring tubes and is divided by 1 n 's & 7 s l U v .. t-U'j 24 between the two measuring tubes 72 and 74. Any of the valves known in the art for feeding a solid material such as tobacco into a column may be used in accordance with the present invention. An example of the feed vent 5 brick is a multi-blade rotary valve as shown in Figure 2. The tobacco thus distributed forms substantially vertical tobacco columns in each of the measuring tubes 72 and 74. Each of the vertical tobacco columns has a predetermined height, the column has about 3 to 4 feet (about 0.9 to 1.2 m). When the height of the tobacco in one of the two tubes falls below a predetermined desired height, the sensing means actuates the inlet valve so that additional tobacco is inserted into that tube until the desired height is reached.

After the tobacco is divided and fed into each of the measuring tubes 72 and 74, it is subjected to steam pre-heat treatment, which also moisturizes the tobacco. The preheating of the tobacco provides heat to form a suitably short cycle-loss condition in the impregnation zone. In addition, the added moisture in the tobacco contributes to the formation of a good expansion effect and an increase in tobacco tendency of <25. In accordance with the present invention, it has been found that when the tobacco supplied to the impregnation zone 22 has a moisture content of greater than about 20% by weight, preferably between about 24% by weight and about 30% by weight, and preheated to a temperature above about 150 ° F (66 ° F). C), increased swelling can be achieved for '30. In the present invention, biscuit-j? Preferably, the tobacco is preferably both moistened and preheated by steam injection into each of the measuring column bodies. Steam heating is desirable because heat can be efficiently and efficiently transferred to the tobacco while simultaneously increasing the moisture level. In addition, since the tobacco is wetted with steam in the measuring tube, the tobacco in the tube above the steam jet or zones may act as an insulator, thereby increasing the efficiency of using steam jet to heat the tobacco.

5 Steam is injected into each of the measuring tubes at points 72 and 74 located below the top of the tobacco column in the tube. The two preferred steam jets are generally designated by reference numerals 80 and 82 in Figure 2, and each is described in more detail below. These jets require dry steam, which can be provided by overheating or by external heating of the steam pipes and the manifold to prevent condensation. Further, the temperature of the sprayed vapor is sufficient to heat the tobacco to a temperature above ambient temperature, preferably above about 125 ° F (52 ° C), more preferably above 150 ° F (66 ° C), for example 150 to about 200 ° F. (66 ~ 93 ° C).

Figures 3 and 4 show two embodiments for providing steam injection onto tobacco columns. Figure 3 is a top view taken along line 3-3 of the steam jet 80 of Figure 2. The steam is injected through the conduits 84 into an external manifold 86 which surrounds the measuring tube 72. The manifold is spaced from the outer wall of the measuring tube to form an annular closed space 88. This space contains the injected steam. Distribution manifold 86 is in communication with the inside of the measuring pipe through a plurality of ports 90, which ports are positioned along the opposite surfaces of the '30 pipe. The steam passing through the ports 90 penetrates the tobacco column as indicated by arrows in Figure 3.

Figure 4 shows another preferred embodiment of the steam-35 injection device for introducing steam into the tobacco columns. In Fig. 4, the steam injection device 82 is an insert fork-like member formed by a 103635 26 hollow bridge 92 supporting a plurality of apertured hollow spikes 94. between. The hydraulic piston or similar motor means is axially connected through the shaft to move the steam jets between the two positions so that the spikes 94 project into and out of the tobacco column as indicated by directional arrow 10 in Figure 4. When the spikes are inserted into body spike. The vapor then exits the spikes through a plurality of openings 98 in each spike tongue, into the tobacco column as indicated by arrows 15.

Although the use of both embodiments of the steam jet is shown in Figure 2, it will be apparent to one skilled in the art that either of the steam jets may be used alone. However, it may be advantageous to use a combination of the two steam jets to ensure that the steam is sprayed across the width of the tobacco column.

The vapor injectors of the present invention are preferably disposed at selected locations along the height of the tobacco column so that substantially all of the vapor injected into the column is condensed before exiting the top of the tobacco column. The sprayed vapor passes upward in the tobacco column and heats the tobacco within the tobacco column as it rises upward. As the heat gradually disappears from the steam, it condenses as the moisture in the tobacco until all the steam is condensed.

1 35 Following preheating and moistening, the tobacco passes downwardly in the column to distribute it in a batch tube 110, shown in Figure 2. The divider of the tobacco column 27 10o63b, generally designated 12 in Figure 2, is operatively connected to each measuring column 82, the divider of the tobacco column is disposed for even-5 rearward motion between the first position outside the column and the second position inside the column.

A top view of the preferred embodiment of the tobacco dispenser 10 is shown in Figure 5. As shown in Figure 5, the tobacco dispenser 112 comprises an actuator bar 114, a bridge 116, and a plurality of closely spaced peaks 118. The dispensers move between said first and second positions to distribute the tobacco column 15. and to the lower portion and therewith to measure a predetermined amount of tobacco for dispensing from the bottom of each tobacco column. As the prongs 18 are inserted into the tobacco column through the opening described below, the upper portion 20 of the tobacco, located above the dispensing means, is supported by the prongs. Accordingly, the tines are spaced close together, for example about 1/4 to 1 1/2 inches apart. The lower portion of the tobacco column below the prongs is then dispensed to the batch conduits 110.

25

The pronged tobacco divider 112 is preferably configured vertically to selectively engage the tobacco column at a plurality of predetermined vertical positions. Fig. 7 shows a region H of heights where the position of the tobacco column distributor can be adjusted. This provides flexibility in selecting the amount of tobacco to be dispensed into the dosing tube 110 as the position control of the dispenser adjusts the size of the dispensed tobacco charge at the bottom of the column.

35

The prongs 118 of the divider 112 access the tobacco column through a plurality of vertical elongated slots 103635 28 aligned with the prongs 118 through the double-walled portion of the measuring tube as best shown in Figures 6 and 7. Figure 6 shows a first outer side wall 120 having elongated vertical slots 122 formed therein. The outer sidewall 120 is partially cut away in Fig. 6 to show the inner sidewall 124 at one end thereof having a second row of vertical slots 126 aligned with the vertical slots 122 and associated with a plurality of horizontal ridges 128. In addition, a plurality of ridges 130 is likewise preferably connected to the outer wall 120. The double-walled structure serves as a capture vessel for receiving tobacco particles that can adhere to the peaks of the dispensing member 15 when the peaks are removed from the interior of the tobacco column. The brushes help remove tobacco particles from the peaks. When the spikes are pulled back from the inside of the tobacco column to the outside of the wall 120, they touch the two rows of brushes and the tobacco particles are scraped 20 off the spikes and fall into the opening 132 between the walls. The tobacco particles fall downwardly in opening 132 into the lower portion thereof and exit through opening 134 through port 134 in the lower portion thereof.

The blocking member, preferably in the form of a rotary valve 140, engages the bottom portion of each measuring tube. The blocking member 140 is engageable with the tobacco column in a vertical position below the dispenser 112 to support the tobacco column when the dispenser is detached for 30 hours with the column. The blocking member 140 is also removable from engaging with the tobacco column to release the lower portion of the tobacco column below the dispensing means 112 into the loading conduits 110. 1

The Estoelin 140 is a preferential airlock circulation valve. The airlock rotary valve may be any of the valves known to those skilled in the art, and preferably, the valve is a wingless rotary valve used for intermittently receiving and delivering one batch of tobacco at a time, as shown in Figure 7. The wingless rotary valve of FIG. 142, 5, which supports a fold or pocket 144 that is pivotable within the housing. A continuous rotary valve, such as one having a plurality of blades, may also be used.

The blocking member 140 is shown in Fig. 7 in a depleted position supporting the tobacco column. When the new tobacco cartridge is intended to be dispensed from the bottom of the tobacco column, the pronged dispensing member 112 is mounted on the tobacco column and rotated by 180 ° from its locking position to its tobacco receiving position such that the open end 146 of the cap 144 is positioned upwardly in contact with the tobacco column. In this position, the kippet receives the tobacco in the lower portion of the column and is then moved again 180 ° to dispense a pre-sized batch of tobacco into the riser pipe 110. The use of an airlock circulation valve as a blocking member is particularly desirable also forms a seal 148 between the tobacco column and the blowing agent impregnation zone 75.

The batch dosing system according to the invention offers several advantages. The amount of tobacco delivered to the impregnation zone can be easily and accurately controlled. Thus, the dispensing means 30 can be positioned vertically to different positions to provide any of a plurality of predetermined batch sizes of impregnation. In addition, the use of measuring tubes provides a substantially uniform distribution of tobacco across the width of the lower charging tube 35. Batch dispensing of the tobacco charge is rapid and may be provided in the impregnation zone of each tobacco charge in agreement with the short 103635 30 impregnation cycles of the invention.

Referring now to Fig. 2, a predetermined amount of tobacco is thus dispensed into batch conduits 110 for loading into the impregnation device Poland. As shown in Figure 2, individual tobacco cartridges 150 are charged to Poland at a charging station 24 (Figure 1) by a pair of opposed semi-cylindrical loading and compression members 152 which are mounted 10 to reciprocate in horizontal pipelines 110. Preferably, they are formed of a material, such as hardened aluminum, which can withstand the wear and tear associated with repeated horizontal movement of the cartridge members inside the cartridge chambers. Further, preferably, as best shown in Figure 2A, the upper and lower surfaces of the loading and compression members are covered by a reinforced plastic sleeve 154 which forms a lubrication between the inner wall and the outer surface of the loading members to prevent bending or stalling of the loading members. Exemplary materials used to form the slides include a polyetheretherketone (PEEK) available from ICI America and RTP Co.

* 25

The loading members 152 are coupled to and from reciprocating motors, such as a hydraulic piston 157 or the like, between the retracted position and the extended position 30 for cyclic motion. The tobacco charges are dispensed to the loading conduits 110 through an opening 158 in their upper wall. Aperture 158 extends substantially across the width of the loading conduits and is disposed between the retracted position of the loading member 152 and its extended position. A pivotable cover member 160 for closing this opening is also provided and is capable of compressing the tobacco charge into the loading chamber when in a cover position as indicated by the dotted lines in Figure 2. Preferably, a pair of barrier members 162 which may be spiked members are provided. The blocking means 162 are mounted to move between the first detachment position outside the loading line 5 and the second blocking station inside the loading line and prevent the tobacco from being blown along the line when the lid member is closed.

10 for loading the tobacco charge into Poland 16, the tobacco charges 150 are dispensed from the rotary valve 140 through the opening 158 into the charging tube 110. The closure members are inserted into the conduits 110 and . The semi-cylindrical charging members 152 are then moved to their extended position. The tobacco cartridges are moved horizontally through the guide tubes of the loading tubes 20 by the loading members 152 and compressed onto the spool 16. The opposed semi-cylindrical shaped loading members cooperate in their fully extended position to form a diaper spool around the connecting rod 20 such described below. Further, the cylindrical sheath formed by the charging members may be partially defined by one or two elongated frame members (not shown), which may be arranged in '30 positions above and / or below the spool axis.

Preferably, such frame members are arranged to engage at the edges of the semicylindrical loading members to form a closed cylindrical space around the compressed tobacco.

35

The charged bobbin is moved to its impregnation position as shown in Figures 1 and 8, and the sealing rings 30 32 105635 at each end of the bobbin are forced radially outwardly by hydraulic fluid from the hydraulic conduit 32 to seal the pressure chamber 22 against leaks. Preferably, the sealing rings are vulcanized or otherwise bonded to annular grooves formed in the circumference of the bobbin ends. The deformable plate or ribbon 153 is disposed at the interface between each elastomeric sealing ring and the fluid conduit 32 such that the sealing rings are not connected at this point and can thus be forced outwardly.

The annular members 160, which may be wear rings, scraper rings or the like, are likewise secured to annular grooves formed on the circumference of each cylindrical end member of spool 15 and axially adjacent at least one end surface of each of the conductive sealing members 30. The wear members have a larger circumference than the circumference of each cylindrical end member of the bobbin, which narrows the annular space or gap between the bobbin assembly 20 and the diaper 14. By narrowing this gap, the elastomer of the elastomeric sealing rings 30 receives better axial support while being used for sealing. This minimizes compaction. disintegrating deformation of the rings due to "overflow or pinching" of the peripheral edges of the sealing rings into the annular space between the cylindrical end members of the bobbin assembly and the casing.

Preferably, each sealing ring 30 is connected to the surface of the wear member 160 and to the circumferential surface of the bobbin end member. Even more preferably, the wear members 160 are disposed axially adjacent to and connected to each end face of the elastomeric sealing rings 30. The wear members may be attached to the elastomeric sealing members 35 by welding, adhesive bonding, vulcanization, and the like.

j 33 10 3 6 ό 5

FIG. 8 likewise illustrates a preferred gate structure that allows high pressure gas lines 38 and 40 to communicate through the sheath 14 upon rapid delivery of the blowing agent. A plurality of ports 42 are circumferentially distributed around the circumference of the sheath 14. The enlarged cross-sectional area of the gate openings formed by the array of gates 42 provides an increased high-pressure medium inlet velocity into the pressure chamber 22 and the outlet rate from the pressure chamber 22 when the bobbin 10 member 16 is in the impregnation position. Preferably, gates 42 are oriented diagonally and taper into smaller diameter openings, as shown in Figures 8 and 8A, to prevent the introduction of particulate tobacco into the gates as the bobbin assembly moves from position to position.

15

The outer distribution channel 45 surrounds the sheath 14 and forms an annular space around the circumferentially divided gates. The gates 42 are aligned with the annular groove 162 at the end of the bobbin, which communicates 20 with a plurality of radial passages 164 and axial passages 166 with the grooves 170 formed on the surface of the connecting rod 20. Once introduced through gas line 38, the high-pressure medium flows through gates 42 to channels 164 and 166 until it reaches grooves 170.

Herein, the medium is exposed to tobacco that is loaded and compressed around the spool connecting rod 22 and flowing out of the channels and into the tobacco as shown by arrows in Figure 8. One or more shields (not shown) surround the connecting rod 20 to prevent the tobacco from clogging the grooves.

Figures 10, 11 and 12 show an alternative device for improving the efficiency of a spool and diaper impregnator by increasing the rate of delivery of the high pressure gaseous blowing agent 35 to the annular high pressure impregnation zone and the rate of removal therefrom. As shown in Figures 10 and 12, the device 103635 34 is shown in a bobbin assembly frame 16 in motion between the loading station and the impregnation station. Thus, the bobbin assembly 16 is shown partly inside and partly outside the shell 14. In this device 5, each port 42 through the shell 14 is preferably in the form of an enlarged cross-sectional area, which preferably has approximately the same cross-sectional area of the openings 46 and 48 through the gas conduits 38 and 40 which supply the blowing agent 10 therewith. . This allows a reduction in the frictional interaction between the gates and the expansion medium, resulting in a faster feed rate of the expansion medium entering and exiting the impregnation as a net result.

15

Since the expanded gates 42 have a larger diameter than the size of the tobacco particles, for example a tobacco clip filler, the device of Figs. 10-12 includes a gate closing member 260, best seen in Fig. 2011, to prevent or minimize tobacco penetration into the expanded gates. The gate closing member 260 is an elongate body having an outside surface 262 that is wider than the gate diameter. As best seen in Figures 11 and 12, the closing member 260 is • ♦ 25 longitudinally coupled between the peripheral portions of the end members 18 of the bobbin assembly 16 and is radially aligned with the port openings 42 (Fig. 12). 1

As shown in Fig. 11, the closing members extend across the portion of the connecting rod 20 of the spool 16, which in turn forms a 'chamber' for the spool to hold the tobacco. When this portion of the bobbin is passed through the jacket, the closing members 260 cover the gates 42 extending through the jacket 14 such that tobacco in the bobbin chamber 35 is prevented from entering the expanded ports 42. As best seen in Figures 11 and 12, the outer surface 262 of the closing members 260 is preferred. curved to coincide with the inner surface of the shell 14. The lower portion of the closure member is preferably convergent in order to minimize the reduction in the volume available for filling with tobacco.

5

Preferably, at least two enlarged gates are provided through the jacket and a corresponding number of closing members are provided in Poland, as shown in the figures. The distribution channel 45 is arranged around the outer surface of the sheath 14 and defines an annular space 44 associated with each port 42 such that the expansion agent introduced into the distribution channel through port 38 'may communicate with the spool simultaneously through each of the sheath ports 42. Similarly, the blowing agent which is discharged through the manifold port 40 'following use, may likewise exit the jacket through each port 42. This also increases the rate of blowing agent feed rate and removal rate from the bobbin and diaper impregnator, allowing for a reduction in cycle time.

20

Returning to Figure 1, following the introduction of the blowing agent into the impregnator, the compressed and impregnated tobacco is held under impregnation conditions for a short period of time ranging from 1 to 2 seconds to approximately 20 seconds. After this • · 25 'the pressure is released. Preferably, the pressure release is substantially immediate, i. it is allowed in about 1 second or faster. This can be accomplished in part by using a high-speed valve with a large port for rapid pressure release. The sensor, not shown, is preferably arranged to detect pressure inside the impregnator and trigger the emptying of the sealing rings 30 in the bobbin body when the pressure therein reaches a predetermined pressure above ambient pressure, for example 5 psig. The second pressure sensor 35 detects the pressure of the hydraulic fluid in the conduit 36 which feeds the sealing rings. Prior to the time when this pressure reaches ambient pressure, for example at 36

11; λ {A £ I v-'uUuJ

5 psig, this sensor triggers the action of the hydraulic piston connected to the arm 28 to move the bobbin body. The bobbin is then moved to the unloading station 26 substantially immediately so that expansion of the tobacco can be achieved.

5

A pneumatic discharge device such as an oil-free compressor (not shown) is disposed within the tobacco discharge zone and targets a tobacco such as high pressure air or nitrogen to wrap around the spool 16 as the spool is moved to and from the discharge station 26. The expanded tobacco, which has been removed, expands substantially immediately into the unloading station 26 and, as shown in Figure 1, is fed to a recovery chute 172 and then to a conveyor 174, for example a screw 15 conveyor or the like. The tobacco, which preferably contains a substantial amount of moisture, for example more than 13% by weight, is conveyed to the drying zone 176 by means of a conveyor 174.

As best illustrated in Figure 9, expanded tobacco is introduced into the conduit 178 in the drying zone where it is picked up by the upwardly moving heated air. Preferably, the heated air has a temperature of less than about 350 ° F (177 ° C) and is preferably at a temperature of between about 200 ° F (93 ° C) and about 300 ° F (149 ° C). The tobacco is conveyed through the drying zone at a temperature and time sufficient to reduce its moisture content to less than about 13% by weight, preferably to a value of from about 6% to about 12% by weight. The dried, expanded tobacco '30 is then transported to a separation zone 180. Here an intermediate '! the substances, including the blowing agent, are passed through a screen 182 or other separating device such as a hydraulic separator and into a recovery loop 184.

! Preferably, the gas passing through the recovery loop is predominantly nitrogen or other inert gas and is injected into the loop, as indicated by zone 186 of the gas injection. Nitrogen is heated by heater 188, transported through blower 190, and then proceeds to a loop to pick up tobacco. The purge stream 192 is continuously withdrawn from the loop and transported to a thermal oxidation zone where the propane in question is burned.

The tobacco passes from the separation zone 180 to a pair of airlock circulation valves 194 and 196 and is then recovered in the recovery zone 108. The two valves act to ensure that no propane gas is conveyed outward to the recovery zone. Therefore, an inert gas such as nitrogen is passed between the two valves. Similarly, as shown in Figure 2, nitrogen may be released into other areas of the system for a similar reason. In this regard, the sheath 200 in Figure 2 may be arranged around the lower portion of the device as indicated by dashed lines. This jacket is provided to recover any propane that is removed from the system during use. Nitrogen is continuously added to various locations in the system. Propane, which leaves the various leaking points in the system, is recovered in a jacket and transported to the thermal oxygen for combustion.

* 25

Returning to the drying treatment, even though the blowing agent is propane or the like blowing agent of the type described in U.S. Patent No. 4,531,529,

White and Conrad, no heating of tobacco is required to fix the '30 tobacco in expanded form, it has now been found that tobacco with a high moisture content can be expanded to a greater extent than tobacco with a normal moisture content. However, it has also been found that some or all of the increased swelling may be lost as high moisture tobacco can collapse.

The drying treatment of the present invention has been found to maintain increased swelling.

38 i ϋ ö 6ό '3

Preferably, the drying treatment is carried out rapidly after the expansion of the tobacco, for example less than about 5 minutes after the expansion, preferably over a period of less than about 1 minute following the expansion. The drying may also be carried out substantially immediately following the expansion. For example, the blower used to remove the expanded tobacco from Poland may use heated nitrogen if desired and the tobacco may be immediately transferred to the drying zone.

10

The effect of moisture content on tobacco expansion is illustrated with reference to Figure 13, which is a schematic showing tobacco expansion at different moisture levels and different tobacco preheating rates. In each case, the tobacco was impregnated with propane for 15 seconds at a pressure of about 2500 psig and heated to about 300 ° F (149 ° C). Prior to expansion, the tobacco had a fill value of about 450 cm 3/100 g. As can be seen in Figure 13, increasing the moisture content of the tobacco to 20 levels above about 20% greatly improves its expansion, especially when the tobacco is preheated to about 150 ° F (66 ° C) or higher. When propane is used as an impregnation medium, the cumulative amount of heat introduced into the impregnation zone from the heated propane 25 and the preheated tobacco is preferably sufficient to provide impregnation conditions in the impregnation zone. between about 240 ° F (116 ° C) and about 270 ° F (132 ° C), preferably about 260 ° F (127 ° C). It has been found that at temperatures and pressures of about 260 ° F (127 ° C) and 2500 psig, impregnation can be achieved in about 5 seconds or less when heat is supplied by both preheated tobacco and preheated propane.

The amount of tobacco compression during impregnation also affects the amount of expansion. Preferably, the tobacco is compressed at a compression ratio of at least about 1.5: 1 during impregnation. The compression ratio is 39

1P7x ^ h I U U O

determined on the basis of the volume of tobacco before compression. The volume of tobacco before compression, or the bulk fill volume of the tobacco, is determined by measuring the density of the tobacco in a cubic container of 5 one foot by one foot by one foot. The tobacco is poured into a cubic container and weighed to determine the bulk density of the tobacco. The bulk fill volume of the tobacco batch before compression to Poland may then be determined by the weight of the batch and the density of the bulk tobacco 10. The bulk fill volume of the cartridge is divided by the compressed volume of the tobacco cartridge, i. the volume treated in an impregnation device, such as in Poland, to determine the compression ratio, all values are determined at the actual moisture content of the tobacco charge or corrected to which charge is fed into the impregnation zone. Thus, in Poland, with a cubic inch impregnation volume, the compression ratio for tobacco with a bulk volume of 50 cubic inches results in a compression ratio of 2: 1.

20

Preferably, the tobacco is compressed to a compression ratio greater than 2: 1, to a ratio of 3: 1 or greater. Compressing the tobacco increases the density of the tobacco so that the density of the tobacco 75 introduced into the impregnation zone is substantially higher than the density of the tobacco prior to compression. Those skilled in the art are aware that the bulk bulk densities of tobacco can vary greatly depending on whether the tobacco is in leaf or cut filler form; the type of tobacco, the moisture content of the tobacco, and other factors. Packing densities of 20 to 35 pounds per cubic foot, calculated on a moisture content of 12%, are readily available in the present invention. Although increasing the packing density may somewhat increase the cycle time to achieve identical amounts of expansion, packing densities greater than 25-30 pounds per cubic foot, based on 12% moisture, and higher, have also been successfully used in the present invention to achieve impregnation times of less than 20 seconds and fill capacity increases of more than 50-100%.

Fig. 14 is a diagram showing how the expansion can vary by varying the tobacco densities during impregnation and at different impregnation times. This graph shows the impregnation of tobacco samples having a moisture content of 27% with propane under the same conditions as described above. Impregnation times ranged from 4 seconds to 20 seconds. Tobacco samples having an initial bulk volume of about 6.2 pounds / cubic foot at 12% humidity and 76 ° F (24 ° C) were compressed to densities of 20, 25, 30, and 36 pounds / cubic foot (all 15 densities calculated or corrected to 12% humidity). ). As can be seen in Figure 14, the amount of expansion increases with increasing impregnation time and with reduced tobacco compression. However, excellent expansion is achieved even at high pack-20 heights and short impregnation times of 10 seconds or less.

Figure 15 shows the flexibility of the expansion method and apparatus of the invention. This graph is combined with various expansion data and shows the total increase in tobacco volume per hour (in cubic meters per hour) that can be achieved from the device of Figure 1 as a function of impregnation time and tobacco compression. This information assumes that the available volume for filling the tobacco is 400 cubic inches and that the method is used continuously at the cycle times shown. As is evident, tobacco yields increase as cycle times are shortened and tobacco compression is increased. As also shown in Fig. 15, the increase in tobacco per hour is 35 highest with short cycle times and increased tobacco compression. This is due to the increased throughput, and despite the fact that the amount of swelling for each batch of tobacco was not necessarily as high as could have been achieved at lower densities and / or longer cycle times.

Accordingly, the present invention provides a flexible method 5, allowing for variations in the amount of tobacco expansion and tobacco throughput.

The various aspects of the tobacco expansion method described herein have been described in detail using pro-10 Pan expansion agent and impregnation conditions near or above the supercritical temperature, together with elevated pressure conditions approaching or above the supercritical pressure, and in conjunction with the device.

It is obvious that the methods and devices of the invention can be varied with numerous modifications; for example, when recovery of a blowing agent such as propane is not desired, the blowing agent may be incinerated following its use. In addition, the various significant tobacco expanding methods and devices described herein, although particularly suitable for tobacco expanding methods and devices employing a high density blowing agent at supercritical temperatures and using short impregnation times, have also been contemplated for a wide variety of other expansion methods, expansion media and equipment.

Tobacco refilling capacities, as referred to herein, are normally measured electronically using 30 automatic refill capacitance meters, wherein a solid piston, 3.625 inches in diameter, is slidably mounted on a cylinder of the same size and exerts a pressure of 2.6 pounds / cubic inch on a tobacco sample placed within the cylinder. These parameters are believed to simulate the packaging conditions to which the tobacco is subjected during the process of forming the cigarette rod. The measured tobacco samples having 50 g weight 103635 42 no are used for expanded tobacco. Samples of 100 g are used for unsweetened tobacco.

The moisture content of the tobacco samples is measured by placing a 5 stick 100 g 'tobacco sample in a wire basket and then placing the basket in a convection oven having an air temperature of about 200 ° F for about 3 minutes. The tobacco and yarn basket shall be weighed before and after oven heating and the weight loss, expressed as a percentage by weight of tobacco, before heating, shall be expressed as the moisture content.

The invention has been described in considerable detail with reference to the preferred embodiments.

However, many changes, variations, and modifications may be made without departing from the spirit and scope of the invention as described in the foregoing description and as defined in the appended claims.

20 • · '' 25

Claims (11)

Apparatus for dispensing heated tobacco into an impregnation zone (22), characterized in that it comprises: a tobacco delivery tube (68); a measuring device (70,72,74) associated with said tobacco delivery tube (68) for measuring the tobacco charge supplied to the impregnation zone (22); 10 vapor spraying means (80.82) for injecting steam into the tobacco charge to preheat the tobacco to a temperature greater than about 52 °; and means (110,152) arranged to supply heated tobacco to the impregnation zone (22). 15 Apparatus according to claim 1, characterized in that said means for feeding tobacco into the impregnation zone (22) comprises a horizontally oriented tube (110) having an opening (158) in its upper wall and arranged to deliver tobacco to the impregnation zone (22). Device according to Claim 2, characterized in that the opening 25 in the horizontal conduit (110) is provided with a pivotable closing member (160) capable of squeezing tobacco into said horizontal conduit (110). Device according to one of Claims 1 to 3, characterized in that the vapor spraying means include means (84,86) for transferring steam through a plurality of apertures (90) through at least one wall in contact with said tobacco charge. 1 Apparatus according to any one of claims 1 to 4, characterized in that said steam injection means (80,82) comprises means for spraying the tobacco at a temperature sufficient to heat the tobacco to at least 125 ° F (52 ° C). 44 10 ό 6 3 5 Apparatus according to any one of claims 1 to 4, characterized in that said vapor injection means (80,82) comprises means for vaporizing the tobacco at a temperature sufficient to raise the tobacco temperature above 150 ° F (66 ° C). . Apparatus for compressing tobacco into an impregnation zone (22), characterized in that it comprises: 10 pairs of opposed conduits (110); a spool member (16) mounted for at least central rearward movement of the impregnation station (22) located at least between the open ends of the first ends of said opposed conduits (72,74) and the inside of the cylindrical jacket portion (14); the bobbin member (16) comprising first and second cylindrical end members (18) and a connecting rod (20) extending between the first and second end members (18), the end members (18) and the connecting rod (20) defining an annular space connecting rod (20). 20) around; tobacco compression means (152) mounted on the inside of each of said tubing (110) for reciprocating movement between a retracted and ejected position for moving the tobacco through the tubing (110) and for compressing the tobacco 25 into an annular space (22); and wherein each tobacco compression means (152) comprises a semi-cylindrical end surface, said end surfaces being dimensioned and shaped to cooperatively form a cylinder (16) around an annular space (22), and. further comprising steam injection means for spraying the tobacco to preheat the tobacco to a temperature above about 52 ° C. 35 The apparatus of claim 7, further comprising: an opening (158) in the top wall of each conduit (110) for introducing tobacco into each conduit (110) at a position 45 45 between the retracted position and the ejected position; and a pivotable closing member (160) capable of closing the opening (158) and of being able to compress the tobacco into the conduit. A method of increasing the tobacco filling capacity by expanding the volume of said tobacco, comprising the steps of: compressing an expandable tobacco cartridge (150), inserting said compressed tobacco cartridge (150) into an impregnation chamber (22) resistant to elevated pressure conditions and substantially filled with said charge of compressed 15 tobacco, impregnating said compressed tobacco charge in said chamber (22) with propane under conditions sufficient to produce an impregnated tobacco capable of expanding at least 50% when subjected to said expanding and impregnating conditions, and removing said impregnate. tobacco for conditions sufficient to expand the tobacco, characterized in that the tobacco placed in the impregnation chamber is preheated to a temperature greater than about 125 ° F (52 ° C) in a vapor injection interval. with (80.82) steam injected. A method according to claim 9, characterized in that the propane used to process the 30 tobacco placed in the impregnation chamber is preheated to a temperature above about 270 ° F (132 ° C). 9 The method of claim 9, wherein the amount of heat supplied to the tobacco in the impregnation chamber of the heated propane and preheated tobacco is sufficient to provide impregnation conditions in the impregnation zone between about 240 ° F (116 ° C) and about 270 ° F (132 ° C). C). 46 1 0 3 6 3 5