MXPA97003684A - Coil and armor with seal activated with fluid depresurizac - Google Patents

Abstract

The present invention relates to a process and apparatus for the expansion of tobacco is used to expand the tobacco at fast rates of yield. The apparatus includes a coil and frame unit wherein the coil can be moved within the frame between the loading, impregnation and discharge positions. In the impregnation position, the sealing units seal the radial clearance between the frame and the end members of the coil to provide a pressure vessel for the impregnation of the tobacco. The sealing units include at least one elastically deformable sealing ring associated with the circumferential exterior of the end member. A pressure applying member is operatively associated with an axial end of each of the sealing members to transmit axial pressure releasably to the axial end of the sealing member when the coil is in the treatment position to cause radial expansion of the sealing ring. deformable seal and thereby achieve the sealing of the coil inside the frame

Description

COIL AND FRAMEWORK WITH SEAL ACTIVATED WITH PRESSURIZING FLUID FIELD OF THE INVENTION The invention relates to a pressure vessel and processes for the treatment of high pressure fluid and preferably, processes for treating tobacco with a high pressure fluid, including processes to increase the filling capacity of tobacco, extraction processes and other processes in which the treatment of an elevated pressure material is required. BACKGROUND OF THE INVENTION The apparatus and process of the invention are particularly convenient in relation to tobacco expansion processes, i.e. processes to increase the filling capacity of tobacco. The tobacco expansion processes are used to restore the bulk density of the tobacco and / or volume which is lost during the curing and storage of the tobacco leaf. In addition, expanded tobacco is an important component of many cigars with low content and very small tar content. In current commercial processes for impregnating tobacco with a blowing agent under high pressure, for example, from 200 psig and above, the required pressure vessel is very bulky, having heavy portable lids to withstand the pressure. The seal mechanisms for the covers are specially designed to withstand high pressures. These types of pressure vessels, which are generally called autoclaves, usually have a cylindrical body portion with convex ends, one or both ends being removable to allow loading and unloading. A goal in any process is to increase the performance of the material. However, many tobacco expansion processes include a high pressure impregnation step along with other steps which can not be performed under high pressure. This, in turn, requires that the pressure be released at a certain point and the treated tobacco removed from the pressure vessel. As a result, the entrance to and exit from the pressure treatment step is a limiting factor to improve the efficiencies in the high pressure tobacco treatment processes. Therefore, tobacco expansion processes employing a high pressure impregnation step are limited in their performance efficiencies by the equipment used, particularly the pressure vessel. Specifically, in the processes of tobacco expansion, a volatile agent of tobacco expansion is introduced into the cellular structure of the tobacco which has broken due to the curing process. Generally, this step is known as impregnation. The impregnated tobacco is then exposed to conditions that cause the blowing agent to volatilize rapidly, causing the tobacco cell to expand when the compound is expelled from the cell in a gaseous state. The volatilization of the blowing agent is achieved by heating the impregnated tobacco in many cases or by rapidly reducing the pressure in other cases. There are several processes which use these basic concepts with different blowing agents, some of which are disclosed in U.S. Patent No. 30,693, U.S. Patent Nos. 3,524,452; 3,771,533 and 4,531,529; British Patent Specification Number 1,484,536 and Canadian Patent Number 1,013,640. The amount of pressure used to impregnate tobacco generally depends on the particular blowing agent employed. U.S. Patent Number 3,524,452 to Stewart et al. Discloses a process in which relatively low pressure can be used since the impregnant is normally in a condensed state at these pressures, while Canadian Patent Number 1,013,640 and British Patent Specification Number 1,484,536, disclose processes that use carbon dioxide as the impregnating compound and require a much higher pressure to ensure that carbon dioxide is introduced to the tobacco cells in sufficient quantity to cause expansion of the cells when the impregnated tobacco is heated .

Some of the disadvantages of using any of these systems and other high pressure systems of the prior art are the magnitude of the autoclave and covers, the difficulties with the sealing of the system, the basket or special container required to contain the tobacco and apparatus associated with the loading and unloading tobacco to and from the pressure vessel. U.S. Patent No. 4,554,932 to Conrad and White, herein incorporated by reference, discloses a fluid pressure treatment apparatus including a tubular frame housing a coil unit. The coil includes a connecting rod which is preferably of a relatively small diameter, which extends between two cylindrical coil ends. The coil ends have a larger diameter than the connecting rod, but smaller than the inner diameter of the tubular frame. The coil is mounted for reciprocal movement between a loading position outside the frame, a treatment position within the frame and a discharge position outside the frame. When the coil is inside the tubular frame, the deformable sealing rings carried in annular grooves at the ends of the coil are forced radially outwardly to engage with the inner wall of the frame. This provides a pressure chamber sealed annularly inside the frame, in the space between the ends of the coil and around the smaller body of the coil. When the coil is in this sealed treatment position, one or more ports through the frame are transversally aligned with cavities in the form of ducts extending radially to one or both ends of the coil and axially along the coil body , to allow the entrance and elimination of process fluids to and from the annular space around the connecting rod between the ends of the coil inside the frame. US Patent Application No. 08 / 163,049 filed December 6, 1993, by Beard et al., Entitled "Process and Tobacco Expansion Apparatus", now US Patent No. 5,469,872 discloses an apparatus and process for expanding tobacco at rapid speeds. of performance using high pressure tobacco impregnation conditions. A preferred apparatus according to that invention employs the concepts of the pressure vessel including the coil and frame unit of U.S. Patent No. 4,554,932 set forth above. An improved coil unit disclosed therein includes elastically deformable sealing rings joined in the annular grooves near the periphery of the end members of the coil, as well as wear rings to decrease the annular space or gap between the coil unit and the framework. These sealing rings are an integral part of the wear rings and are exposed to a high-pressure fluid, typically a vegetable oil of food-grade quality, on their inner circumferential surface to cause the rings to expand radially outward to achieve their sealing function. Although the coil and the pressure vessel of the frame produce a substantial time saving and improve the economy in the expansion of the tobacco, the fluid used to expand the sealing rings must be carried to the sealing rings providing blind ports inside the body. the coil In addition, the rings must be replaced periodically by removing the old rings and attaching the new rings to the body of the coil. This takes a lot of time and is expensive. In addition, if the pressurized fluid of the elastically deformable ring like vegetable oil spills onto the tobacco, the utility of the tobacco in the manufacture of cigarettes is impaired. SUMMARY OF THE PRESENT INVENTION This invention provides an improved coil unit and improved high pressure tobacco treatment process, preferably of the type disclosed in U.S. Patent No. 4, 554,932 of Conrad and White and in the process and apparatus of US Patent Application Serial No. 08 / 163,049, filed December 6, 1993, by Beard et al. And now U.S. Patent Number 5,469,872 and US Patent Application Serial Number 08 / 076,535, filed June 14, 1993, by Conrad and White, now U.S. Patent Number 5,483,977. The present invention provides an improved frame coil and pressure vessel including a sealing unit that can improve the operation of the coil and the apparatus, simplify its construction and / or improve its long-term reliability, while also improving the ease of replacement of worn sealing elements. An improved coil and frame unit according to one aspect of the invention comprises a pressure vessel defined by a tubular frame and a coil unit movable between at least a first position outside the frame and a treatment position within the frame. The coil unit includes two cylindrical end members joined by a connecting rod. At least one sealing unit is carried by each of the end members of the coil. The sealing units seal the ends of the coil when the coil is in the treatment position within the frame. Each of the sealing units includes at least one elastically deformable sealing member, preferably a sealing ring, associated with the circumferential exterior of the end member. An axial pressure applying member is operatively associated with an annular end of each of the sealing rings to transmit axial pressure releasably to the axial end of the sealing member when the coil is in the treatment position to cause radial extrusion. , ie, an increased size in the radial dimension, of the deformable sealing ring and thereby achieve the sealing of the coil within the frame. Preferably, the pressure applying member is an annular member axially positioned adjacent to the sealing member. It is also preferred that the liquid blowing agent of the tobacco be used to apply fluid pressure to the pressure applying member to achieve radial expansion of the sealing ring. Advantageously, a first annular end surface of the annular pressure applying member touches the sealing ring and has a smaller surface area than a second annular end surface of the pressure applying member which, in turn, It is in fluid communication with the expansion agent. As a result, the pressure applying member applies a contact pressure to the sealing ring which is greater than the fluid pressure of the blowing agent, per se. In another aspect of the present invention, the coil is advantageously formed of one or more radially central components supporting a plurality of discrete annular components, the latter including the sealing units. With this construction, the annular sealing members can be easily replaced. A preferred component coil includes a radially central coil body forming the connecting rod between the end members and also a core portion of both end members of the coil. A retaining member associated with the axial end of each end member retains the components of the annular sealing unit in the body of the radially central coil. The replacement of the worn sealing members can be achieved by simply removing the retaining members allowing the sealing units to be then removed from the main body of the coil for replacement of the worn sealing rings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, which form a portion of the original disclosure OF THE INVENTION: Figure 1 is a schematic view of an advantageous tobacco expansion system including a preferred embodiment of an improved reciprocating coil and pressure chamber apparatus according to the present invention. Figure 2 is a detailed sectional view of the coil and frame unit of Figure 1 and illustrates the coil is a treatment position within the frame. Figure 3 is an exploded view taken in perspective of a preferred sealing unit associated with an end member of the coil body of Figure 2. Figure 4 is a detailed elongated sectional view of an end portion of the body of the coil of Figure 2 positioned within the frame unit. Figure 5 is a detailed elongated sectional view of the other end portion of the body of the coil of Figure 2 positioned within the frame unit. Figure 6 is a cross-sectional view taken along line 6-6 of Figure 5 and illustrates a load of tobacco within the annular space surrounding the connecting rod of the coil body. Figure 7 is a partial cross-sectional view taken along line 7-7 of Figure 5 illustrating an end view of an axially mobile compression member which includes paths to allow high pressure fluid to enter the adjacent space to an annular end of the compression member to cause the compression member to move axially toward an elastically deformable sealing member which is positioned adjacent its other annular end. Figure 8 is a partial cross-sectional view taken along line 8-8 of Figure 4 illustrating a cross-sectional view of the end member of Figure 4 and an end view of an elastically deformable sealing member which is positioned near a portion of the circumferential exterior of the end member. Figure 9 is a partial cross-sectional view taken along line 9-9 of Figure 4 illustrating a plurality of cavities provided in the annular end face of a rigid annular spacer support member. Preferably, the spaces receive alignment pins attached to the compression members. Figure 10 is a cross-sectional view taken along line 10-10 of Figure 4 illustrating fluid receiving ports within the annular spacer support members, which are fluidly connected to ports within the coil body to allow the high pressure fluid to exit the annular space surrounding the annular spacer support member and between the two sealing rings as shown in Figure 9. Figure 11 is a detailed sectional view of the sealing unit of the Figures 3, 4, 8 and 9 shown with the elastic sealing member in its radially extruded condition. DETAILED DESCRIPTION OF THE PREFERRED MODALITY The present invention will now be described in a more complete manner in detail with reference to the accompanying drawings, in which the preferred embodiments of the invention are shown. However, it should not be construed that this invention is limited to the embodiments set forth herein, rather they are proportionate for this disclosure to be detailed and complete and to fully convey the scope of the invention to those skilled in the art. Figure 1 is a schematic illustration of an advantageous embodiment of a tobacco expansion system and process which utilizes a preferred coil and frame unit 10 according to the present invention. The coil and frame apparatus is generally constructed in accordance with U.S. Patent No. 4,554,932, published November 26, 1985, Conrad and White and U.S. Patent Nos. 5,469,872 to Beard et al. And 5,483,977 to Conrad and White, the complete disclosures of which are incorporated herein by reference. incorporated in the present by reference. Several details revealed in the above disclosures are not repeated in the present for brevity purposes. However, reference may be made to your complete disclosures for such details. In the apparatus of Figure 1, the tobacco which has preferably been first treated in a single preparation zone or in a series of preparation zones (not shown) to increase its moisture content to a value above about 16. % by weight, preferably above about 20% by weight and also to increase its temperature substantially above room temperature, is supplied to a loading zone 12. The loading zone 12 defines a loading position for a reciprocal apparatus of high pressure fluid treatment with coil and frame 10. The reciprocal high pressure fluid treatment apparatus with coil and frame 10 includes a cylindrical frame or box 14 and a coil unit 16 which can be moved between the position of loading 12, an impregnation position 18 and a discharge position 20. The coil unit 16 is illustrated in Figure 1 placed in the impregnation position 18 where the coil unit is complete. enclosed within the tubular frame 14. In this position, a pressure chamber 22 is formed in the annular space within the frame 14 surrounding a portion of the coil unit 16. The frame 14 and the coil unit 16, best viewed in Figure 2 can be made of suitable materials, including stainless steel and the like. Preferably, a plurality of wear rings 23 made of a bearing alloy such as a bronze bearing grade, for example, an aluminum and bronze alloy, or a similar softer material than the frame 14, is provided around the circumferential surfaces of the coil ends so that the interior surface of the frame 14 is not damaged when the coil moves within the frame. The specific materials, construction and size of the frame and coil will be sufficient to withstand the pressures contemplated with the pressure vessel, as apparent. Returning to Figure 1, the coil is loaded with tobacco in the loading position 12 using various processes or apparatus including the apparatus described in U.S. Patent Number 4, 554,932. In a preferred embodiment, the tobacco is loaded into the reel 16 using the process and apparatus mentioned and described in U.S. Patent Nos. 5,469,872 and 5,483,977, previously disclosed. The tobacco can be provided in various ways, including the leaf form (including stem and ribs), strips (leaf with the stem removed), cigar stuffing, cut filler for cigars (strips cut or shredded to make cigars), or similar, preferably cut filler. Preferably, the tobacco moistened by any of several means known to those skilled in the art at a moisture content of at least about 12% and preferably at least about 20%. The tobacco is also preferably preheated to a temperature above ambient and is then charged to the annular space 22 of the spool 16, preferably under conditions such that the tobacco is compressed thereto at a density of 125% or more as compared to the loose filling density of the same tobacco, normally the tobacco can be squeezed to a density of 20-30 pounds per cubic foot. After charging the tobacco in position 12, the coil unit is moved through the connecting rod 24 to the impregnation position 18 shown in Figure 1.

In order for the coil 16 to be moved within the frame 14, that is, from the loading position to an impregnation position and then to a discharge position, it is important that there be at least a small gap or annular free space. 26 (see Figure 11) between the inner circumferential surface of the frame and the outermost circumferential surface of the coil 16. When the coil 16 reaches the impregnation position 18, a portion of the gap 26 is closed by radial expansion of a plurality of sealing members 28a-28d, shown in Figure 2, in order to provide a pressure chamber 22 between the coil 16 and the frame 14. Once the coil is in the impregnation position, shown in Figure 2 , a tobacco blowing agent, preferably propane, is admitted to the impregnation chamber 22 through a supply pipe 29 and ports 30 through the frame 14 and following a suitable impregnation time. When it can be as short as one to several seconds, the propane is removed through a recovery tube 32, which can be the same as the supply tube 29 if desired. The sealing members 28a-28d, discussed below, are then relaxed and contracted radially and the coil unit 16 is moved to the discharge position 20 schematically illustrated in Figure 1. In a preferred embodiment, the tobacco is discharged while it is discharged. subjected substantially at the same time to the expansion in a drying tower 34 (Figure 1) which removes the excess moisture from the expanded tobacco to stabilize its expansion. However, numerous and diverse apparatus and processes can be used to recover and / or treat expanded tobacco, as apparent. Figure 2 illustrates in detail the frame and coil unit in the impregnation position. The coil unit 16 includes cylindrical end members 35 and 36 and a connecting rod 37. When the coil 16 is inside the frame 14, the end members 35 and 36 together with the connecting rod 37 and the frame 14 define an annular space 22 of the predetermined volume constituting a sealed chamber or pressure vessel. The coil unit 16 is installed for reciprocal movement between the various positions shown in Figure 1 including the loading position 12, the impregnation position 18 and the discharge position 20, by any of the various arrangements and is preferably moved by a quick acting hydraulic cylinder (not shown) which is operatively connected to the coil via the axially oriented shaft or rod 24 partially shown in Figure 1 and Figure 2. The coil 16 illustrated in Figure 2 includes four sealing units 38a-38d arranged in the circumferential periphery of the two end members 35 and 36 of the coil. One of the end members 35 includes a plurality of radially oriented ports 39 for the entrance and exit of the expansion agent a and the expansion zone 22. Three sealing units 38a, 38b and 38c are located in the radially radially end-effected end member. 35 while only one sealing unit 38d is located in the other end member 36 of the coil. This positioning provides an individual sealing unit adjacent each axial end of the two areas of the body of the coil 16 in which the high pressure expanding agent communicates with the circumferential exterior of the coil body 16; mainly the area of the chamber 22 between the end members and the outer circumferential portion of the end member 35 defined by the ports 39 which provide the entrance and exit of the expansion agent. Although this positioning of the sealing units is a preferred embodiment, the present invention is not limited to this precise placement or this exact number of sealing units 38, as apparent. Each member 35 is shown in Figure 4. Two of the sealing units, 38a and 38b in an end member 35 are axially between the pressure chamber 22 and the ports of the expansion agent 39. Each of these sealing units 38a and 38b includes an elastically deformable annular sealing member 28a and 28b and a corresponding compression member 44a and 44b touching an annular end of the sealing member. Axially positioned between the two sealing members 28a and 28b is an annular bearing member 46 which separates the sealing rings 28a and 28b from each other and provides a bearing surface for each of the sealing rings 28a and 28b when they are compressed by the compression members 44a and 44b. A plurality of axially oriented pins 48 are fixedly attached to each compression member 44a and 44b. The pins 48 extend axially from the annular end face of the compression member which faces its respective sealing member 28a and 28b. The pins 48 extend toward and / or through axially aligned apertures 50 (see Figures 3 and 8) extending through the sealing members 28a and 28b. The pins 48 can also extend through a portion of axially aligned apertures 52 (Figures 3, 9 and 10) formed in the annular spacer support member 46.

As best seen in Figure 4, the two sealing units 38a and 38b are positioned within an annular groove formed on the circumferential exterior of the end member 35 such that the circumferentially outer surface of each sealing member 28a and 28b form a portion of the circumferentially outer surface of the end member 35. As best seen in Figure 3, each of the compression members 44a and 44b includes one or more radial channels 58 formed in its annular end surface which is away from its respective sealing member 28a and 28b. The radial channels 58 in the compression member 44a receive a high pressure expansion agent from the impregnation zone 22, as will be discussed below, and therefore allow the high pressure expansion agent to enter a space 60 shown in Figure 11, which is axially between the compression member 44a and an adjacent shoulder portion 64 (also seen in Figure 11) of the end member 35. Corresponding radial channels 58 in the compression member 44b receive the high-pressure expansion agent of radial ports 59 (Figure 4) formed in the end member 35 and therefore allow the high pressure expansion agent to enter the space 62, (shown in Figure 11), which it lies axially between the compression member 44b and an adjacent shoulder portion 66 (also seen in Figure 11) of the end member 35. Returning to Figure 2, each of the compression members n 44a and 44b can be moved axially within the annular groove in the end member 35. When the expanding agent is admitted to the coil body through the ports 39 for impregnation of the tobacco in the chamber 22, it is received to and flows along axial channels 70 formed in the end member 35 and a portion of the expanding agent then flows into the radial channels 59 and into the space 62 (Figure 11) axially adjacent the compression member 44b. The expansion agent is admitted to the space 60 (Figure 11) axially adjacent the compression member 44a through the portion of the annular space 26, which is radially between the frame 14 and the end member 35 and axially between the chamber of impregnation 22 and compression member 44a. The additional expansion agent is also admitted to the space 62 adjacent the compression member 44b through the portion of the annular space 26 located radially between the frame 14 and the end member 35 and axially between the sealing member 28b and the ports 39. in the coil 16. As best seen in Figure 11, the high-pressure blowing agent which enters the spaces 60 and 62 causes the compression members 44a and 44b to move axially, each towards its sealing member adjacent 28a and 28b, respectively and in the direction of the spacer support ring 46. The resulting axial pressure applied to each of the sealing members 28a and 28b causes each sealing member to be extruded radially, i.e., to expand radially and therefore form a seal with the inner surface 72 (Figure 11) of the frame 14 and also with the bottom surface 74 (Figure 11) of the annular groove supporting the sealing unit in the sealing member. end 35. The expansion agent remains in the spaces 60 and 62 during the time in which the tobacco in the chamber 22 is impregnated with the expanding agent and therefore keeps the sealing members 28a and 28b in the expanded state during This weather. As seen in Figure 3, the surface of the annular end face 76a of each of the compression members 44a and 44b which is in fluid contact with the expansion agent, is larger than the surface of the face of opposite end 76b of each compression member 44a and 44b which, in turn, touches and applies pressure to the elastically deformable sealing members 28a and 2ßb. This is achieved by providing the ports 50 through the elastic sealing members 28a and 28b which in fact define areas on the end face 76b of each compression member that has no contact with the sealing member. Accordingly, the compression members 44a and 44b each apply a contact pressure (in force per unit area) to the sealing rings 28a and 28b larger than the pressure applied to each of the compression members by the expansion agent in the spaces 60 and 62. In turn, when the sealing members are extruded, that is, they expand radially, to the sealing contact with the inner surface 72 (Figure 11) of the frame 14 and the surface of bottom 74 (Figure 11) of the annular groove in the end member, the sealing members touch these surfaces at a pressure which is the same as the pressure applied by each of the end faces of the compression member 76b to the annular end surfaces of the elastically deformable sealing members 28a and 28b. Accordingly, the sealing members form seals between the interior of the frame and the peripheral surfaces of the end members of the coil at a sealing pressure that exceeds the fluid pressure of the blowing agent. This allows the sealing members to seal against the leakage of the blowing agent when the coil is in the impregnation position 18 although the force used to expand the seals is derived from the pressure of the blowing agent. The sealing rings can be formed from any of the various high-temperature, elastically deformable stable materials used to form sealing rings, including graphite-based carbon and graphite materials available on the market as GRAFOIL. In an advantageous embodiment, the sealing rings can be formed of an EDP elastomer having a durometer hardness of between 70 and 90, more preferably 80. As seen in Figures 2, 3, 4 and 11, the spacer support ring 46 advantageously includes radially oriented ports 80 which communicate between the circumferential outer and inner surfaces of the spacer support ring 46. The radial ports provide fluid communication at their outer ends with the portion of the annular space 26 (Figure 11) surrounding the ring 46 inside the frame 14. As seen in Figure 4, the radial ports are also in fluid communication with the axial openings 52 through the spacer support ring 46. The radial ports 80 through the ring 46 communicate in their outer ends with a plurality of radial ports 86 in the body of the coil shown in Figures 2, 4 and 10. The radial ports 86 through the body of the The coil is fluidly connected to an axial port 88 extending through the body of the coil which terminates in a vent port 90 on the low pressure side of the coil body. The radial channels 80 therefore allow ventilation of gases trapped in the portion of the annular space 26 surrounding the spacer support member 46 and between the seals of the two sealing members 28a and 28b. In the presently preferred embodiment of the invention, the washers 91, better seen in Figures 3 and 8, are joined at both axial end surfaces of each sealing member 28a-given their areas restricting each axial port 50. The washers 91 prevent that the sealing member is extruded and closes the ports 50 of the sealing member when it expands. It is also currently preferred to permanently join the compression face of each compression member to the adjacent axial face of the respective sealing member, by one of several methods such as vulcanization, as also indicated in Figure 3. As indicated in Figure 8 for distances 93 and 94, the pins 48 extending axially from the compression members, as well as the channels 50 through the sealing members 28a-b are preferably positioned radially closer to the circumferential exterior than to the circumferential interior of the sealing members 28a and 28b and compression members 44a and 44b. In this manner, the distance 93 in Figure 8 exceeds the distance indicated at 94. This preferred positioning of the pins balances the surface areas of the two radial portions of the compression member that touch the sealing member, i.e. the portion radially outer and the radially inner portion to the pins 48. This is believed to ensure that when each of the sealing rings 28a-b is radially expanded, it will receive the same pressure contact at the various radial sites on its axial surface which, in turn, it protects the pins 48 and / or washers 91 so that they are not bent and / or twisted due to unequal pressure. The sealing units 38c and 38d positioned adjacent the axial ends of the end members of the coil 35 and 36 respectively and illustrated in Figures 4 and 5 are similar in construction and operation to the sealing units 3ßa and 38b. Each of these sealing units includes a sealing member 28c and 28d respectively and a compression member 44c and 44d respectively, there bearing axially extending pins 48. The pins 48 are arranged to extend through axial ports 50 in each sealing member 28c and 28d and also through ports 52 extending through an annular spacer support member 146 associated with each of the sealing members 28c and 28d. Each of the compression members 44c and 44d can move axially, relative to their respective compression member within an annular groove in their respective end member 35 and 36. As seen in Figures 2, 4 and 7, a portion of the expansion agent admitted to the coil body through ports 39 for impregnation of the tobacco in the chamber 22 is directed towards and flows along the ports 70 extending through the coil 16 and then through the radial ports 170 and 172 which communicate with radial channels formed in the annular end faces of the compression members 44c and 44d respectively. The expanding agent is also admitted to the radial channels 58 formed in the annular end faces of the compression members 44c and 44d through the portions of the annular space 26 surrounding each of the end members 35 and 36 and located axially. between each of the sealing units 38c and 38d and a space containing the high pressure expansion agent. In the case of an end member 35, the space containing the high pressure expansion agent is the annular space between the frame 14 and the ports 39 in the body of the coil. In the case of an end member 36, the annular space containing the high pressure expansion agent is the annular space between the sealing member 28d and the impregnation zone 22. As best shown in Figures 4 and 5, each one of the end support rings 146 of the coil advantageously includes a plurality of blind radial ports 184 which communicate between the axial openings 52 in the support rings and the non-pressurized space at the outer ends of the end members. and 36, respectively. The radial channels 184 allow ventilation of gases trapped in the axial openings 52 in the support rings. In a tobacco expansion operation, the blowing agent is introduced to the system through a high pressure gas supply line 29 and the ports 30 which communicate through the frame 14. These ports, which can be distributed circumferentially around the periphery of the frame 14, allow the introduction and elimination of the high pressure fluid inside and outside the coil 16 when it is in the impregnation position. An outer manifold 192 (Figures 2 and 4) surrounds the ports 30 and contains the expansion agent admitted to the frame 14 through the circumferential ports 30. The high pressure fluid flows through the ports 39 in the end member 35. and then to the loaded and compressed tobacco around the connecting rod 37 of the coil through the axial ports and channels in the body of the coil. Preferably, the blowing agent is propane at a pressure preferably above 2,000 psig and more preferably around 2,500 psig and 3,000 psig. The temperature of the propane in the chamber 22 is advantageously maintained above 200 ° F, preferably between 200 ° and 270 ° F, for example, 260 ° F. Under these conditions, the extremely short impregnation times, between 5 and 15 seconds, can be used to impregnate the tobacco while obtaining extremely desirable increases in the filling capacity of the tobacco, for example, greater than 50 to 100% increase in capacity. filling. The expansion agent enters the ports 39 located within the end member 35 of the coil 16 and flows along the axial channels 70 substantially extending the length of the connecting rod 37 of the coil 16 as illustrated schematically in FIG. Figure 2. In the portion of the coil between the end members 35 and 36, the axial channels 70 are open along their radial outer surface and are covered by a cylindrical diffuser sleeve 200, better seen in Figures 5 and 6 , which covers the channels 70 and prevents the entry of tobacco into the channels. The diffusing sleeve is formed from one of the numerous stable materials at high temperature, for example, several layers joined by fusion of narrow mesh metal screen, a perforated metal sleeve, a structural sleeve of ceramic or the like, or other porous materials including screens or other perforated sheet materials. As illustrated in Figure 6, the propane exits through the diffuser sleeve 200 to the tobacco in the impregnation zone 22 for impregnation thereof. The radial expansion of the sealing members in the sealing units 38a and 38b during the admission of the propane to the coil 16 is best illustrated in Figure 11. In a preferred embodiment of the present invention, a spring 202 is provided (Figure 11). ) between the axial ends of each set of axially aligned pins 48 within the spacer support ring 46. The spring is shown in a compressed state in Figure 11 as a result of the movement of the compression members 44a and 44b relative to each other. The spring 202 ensures the return of the compression members 44a and 44b to a relaxed state after the release of pressure and it may be particularly convenient to counteract any pressure caused by some residual high pressure blowing agent remaining within the range of pressure. impregnation 22 after release of pressure. It is also desirable that the springs counteract the entrainment of the pins 48 against the sealing members 28a and 28b. Although not shown in the drawings, the springs 202 are also conveniently provided for each of the pins 48 associated with the sealing units 38a and 38d. Returning to Figure 1, after introduction of the propane blowing agent into the impregnating apparatus, the compressed impregnated tobacco is maintained under impregnation conditions for a short period of time ranging from less than one second to twenty seconds. Afterwards, the pressure is released. Preferably, the release of the pressure is substantially instantaneous, that is, it is achieved in one second or less. This can be achieved in part by employing a large port size quick acting valve in the recovery tubes 32. A sensor (not shown) is advantageously provided to detect the pressure inside the impregner. When the pressure in the impregnation 22 has decreased to a predetermined pressure in ambient pressure or near, the coil is moved to the discharge position 20 so that the expansion of the tobacco can be effected. A pneumatic discharge device such as an oil-free compressor (not shown) is provided in the tobacco discharge zone and directs the fluid as air or nitrogen at high pressure to the tobacco surrounding the spool 16 when the spool is moved to and from the discharge position 20. The tobacco withdrawn in the discharge position 20 expands substantially instantaneously due to the release of pressure. Expanded tobacco advantageously contains a substantial amount of moisture, ie 12% by weight or more. In addition, as illustrated in Figure 1, the expanded tobacco which is withdrawn in the discharge position 20 can then be treated in a drying tower 34. The heated air, nitrogen, or the like is supplied through a supply pipe. 210 and flows upward to the drying tower 34 to force the expanded tobacco upward to the drying tower 34 for a short period of time in order to remove moisture and stabilize the expansion of the tobacco. The drying tower is lined with a porous liner allowing the heated air or nitrogen used to dry the tobacco to be recirculated through line 214 and passed through a fan 216 and then recirculated through a supply pipe. 218 for supplying the tube 210. If desired, filler air can be added to the drying tower 34 through the outer supply tube 220. In a preferred embodiment of the invention, the coil 16 is advantageously formed of one or more components radially central supporting a plurality of discrete annular components so that the sealing members 28 can be easily replaced. A preferred component coil is illustrated in Figures 2, 4 and 5. With reference to Figures 2 and 4, the coil is formed of a coil body 37 forming the connecting rod and a radially central portion of the two ends of the coil. coil. The rod 37 has a plurality of integral threads 226 formed on its periphery at one or both axial ends. An annular retaining member 228, provided with mating female threads 230 on its inner surface, retains the three sealing units 38a, 38b and 38c together with the annular inlet port component 232 in suitable positions in the main body 224 of the coil. At the other end of the coil body, a second holding member 232 is threadedly connected to an inner end portion of the radially central connecting rod 37. The holding member 232 applies compressive force to a second holding member 234 which retains the sealing unit 38d in the proper place on the radially central connecting rod 37. The replacement of worn sealing members can be achieved by simply removing the retaining members 232 and 230. The sealing units 38a, 38b, 38c and 38d can then be easily removed from the central component 37. The new sealing members 28a-28d can be replaced for the worn sealing members. The coil is then reset for continuous use. The coil of the invention is susceptible to numerous changes and variations. Although the coil has been illustrated for use in connection with a particular blowing agent, it will be apparent that numerous different blowing agents and processes may be employed in connection with the coil and frame apparatus disclosed herein. It will also be apparent that the coil and frame apparatus of the invention can be used in connection with other processes employing a high pressure treating agent, including extraction processes applied to tobacco and other materials and the like. The invention has been described in detail in considerable detail with reference to the preferred embodiments. However, many changes, variations and modifications can be made without departing from the spirit and scope of the invention as described in the above specification and defined in the appended claims.

Claims (25)

1. CLAIMS 1. A coil and frame unit for use in tobacco expansion comprising: a pressure vessel defined by a tubular frame and a movable coil unit between at least a first position outside the frame and a treatment position within the frame. frame; the coil unit comprising a first cylindrical end member and a second cylindrical end member and a connecting rod extending therebetween; at least one sealing unit carried by each of the first and second end members to seal the pressure vessel when the coil is in the treatment position; each of the sealing units comprising at least one elastically deformable annular sealing member associated with the circumferential exterior of the end member for sealing the coil in the treatment position; and a pressure applying member operatively associated with at least one axial end of each of the sealing members to transmit axial pressure releasably to the axial end of the sealing member when the coil unit is in the treatment position for causing radial expansion of at least one circumferentially outer portion of the deformable sealing member.
2. 2. A coil and frame unit according to Claim 1 wherein the pressure applying member comprises an annular shaped member axially positioned adjacent to the sealing member.
3. 3. A coil and frame unit according to the Claim 1 comprising a fluid inlet port in at least one of the end members for admitting the liquid expansion agent into the pressure vessel, the fluid inlet port being fluidly connected to the pressure applying member to make that the blowing agent applies fluid pressure to the pressure applying member.
4. A coil and frame unit according to Claim 2 comprising a fluid inlet port in at least one of the end members for admitting the liquid expansion agent into the pressure vessel, the fluid inlet port being fluidly connected to the pressure applying member to cause the expanding agent to apply fluid pressure to the pressure applying member.
5. A coil and frame unit according to Claim 4 wherein the annular pressure applying member comprises a first axial end surface having contact with a first annular end surface of the sealing member and a second surface of axial end in fluid communication with the expansion agent and wherein the surface area of the second axial end surface is greater than the surface area of the first axial end surface.
6. 6. A coil and frame unit according to the Claim 5 further comprising at least one fluid vent communicating with a second axial surface of the sealing member to release the fluid pressure applied to the second axial surface of the sealing member.
7. 7. A coil and frame unit according to Claim 6 wherein at least one of the cylindrical end members comprises at least two sealing units.
8. 8. A coil and frame unit according to the Claim 7 wherein one of the end members comprises at least three sealing units.
9. A coil and frame unit according to Claim 7 wherein two sealing units comprise an annular bearing member positioned between the sealing members of the two sealing units and contacting a portion of the second end surface axial of the sealing members.
10. A coil and frame unit according to Claim 9 further comprising a vent line in fluid communication with an outer portion of the coil unit, the vent line extending through the annular support member to release the fluid pressure applied to the second axial surface of the sealing members.
11. 11. A coil and frame unit according to Claim 10 wherein the annular support member comprises radial channels communicating with its periphery.
12. 12. A coil and frame unit according to Claim 11 further comprising at least one polarization member associated with each of the sealing units, the polarization member being arranged to assist in the release of pressure by the application member of pressure.
13. 13. A coil and frame unit according to the Claim 2 wherein the coil unit can further be moved to a discharge position in addition to the loading and treatment positions.
14. A coil and frame unit according to Claim 5 further comprising at least one axially directed pin connected to an axial end surface of each of the annular pressure applying members and wherein at least one A portion of the pin extends axially to the sealing member associated with the pressure applying member.
15. 15. A coil and frame unit according to Claim 14 comprising a plurality of pins connected to each of the pressure applying members.
16. 16. A coil and frame unit for use in the treatment of a material with a fluid under high pressure conditions comprising: a pressure vessel defined by a tubular frame and a movable coil unit between at least a first position outside the frame and a treatment position within the frame; the coil unit comprising a first cylindrical end member and a second cylindrical end member and a connecting rod extending therebetween; at least one sealing unit carried by each of the first and second cylindrical end members to seal the pressure vessel when the coil is in the treatment position; each of the sealing units comprising an elastically deformable sealing ring associated with the circumferential exterior of the end member and an annular compression member axially positioned adjacent to the sealing ring, the compression member being arranged for reciprocal axial movement toward and away of the sealing member to provide radial expansion of the sealing member for sealing and removing the seal of the coil unit.
17. 17. A coil and frame unit according to Claim 16 for impregnating tobacco loaded to the coil in the first position with a tobacco blowing agent while the coil unit is in the second position and further comprising a supply of blowing agent. expansion of the tobacco to supply the expansion agent to the pressure vessel.
18. 18. A coil and frame unit according to Claim 17 wherein the connecting rod comprises at least one axially extending fluid channel for delivering the expanding agent to the pressure vessel for impregnating the tobacco.
19. A coil and frame unit according to Claim 18 further comprising at least one radial channel in at least one of the end members for transferring the expansion agent from the expansion agent supply to the fluid channel that It extends axially.
20. 20. A coil and frame unit according to Claim 19 further comprising a fluid supply channel in fluid communication with an axial surface of the compression member for supplying a fluid under high pressure to apply axial pressure to the fluid pressure unit. sealing of the compression member to cause its radial expansion.
21. 21. A coil and frame unit according to Claim 20 wherein the annular compression member comprises a first annular end surface having contact with a first axial end surface of the sealing member and a second axial end surface in fluid communication with the expansion agent and wherein the surface area of the second axial end surface is greater than the surface area of the first axial end surface.
22. 22. A coil and frame unit for use in impregnating tobacco with a high pressure tobacco blowing agent comprising: a pressure vessel including a cylindrical tubular frame and a coil unit; the coil unit comprising a first cylindrical end member and a second cylindrical end member and a connecting rod extending therebetween; at least one sealing unit carried by each of the first and second cylindrical end members to seal the pressure vessel when the coil is in the treatment position; each of the sealing units comprising at least one elastically deformable annular sealing member associated with the circumferential exterior of at least one of the end members for sealing the coil in the treatment position and an annular compression member having a first axial surface of predetermined area having contact with the sealing member and a second axial surface of the surface area larger than the first axial surface and being arranged for fluid communication with the tobacco expanding agent.
23. 23. A process for impregnating tobacco with a high pressure expanding agent comprising the following steps: loading tobacco into an annular space of a coil body defined by the first cylindrical end member and the second cylindrical end member and a connecting rod that it extends between them; moving the coil unit into a tubular frame; applying axial pressure to an elastically deformable sealing ring associated with the circumferential periphery of each of the end members to thereby form a sealed annular impregnation zone within the tubular frame; admitting the expansion agent to the impregnation zone and removing the expansion agent from the impregnation zone and releasing the axial pressure applied to the sealing members. The process of claim 23 further comprising the step of touching each of the elastically deformable sealing members along an axial surface thereof with an annular compression member and touching an annular end surface of the sealing member. compression with tobacco blowing agent to thereby cause the compression member to apply axial pressure to the sealing members. The process of claim 24 wherein the annular compression member comprises a first axial surface that touches the sealing member and a second axial surface that touches the expanding agent and wherein the second surface is of larger surface area than the first surface.