United States Patent (19) 11 3,813,041 Kleine (45) May 28, 1974

(54) APPARATUS FOR STORING A LIQUID FOR 56) References Cited ITS DISTRIBUTION IN THE GASEOUS UNITED STATES PATENTS : STATE 3,129,888 4/1964 O'Hagan...... 239/55 75 Inventor: Jean Jacques Kleine, Letraz-Sevrier, 3,729,289 4/1973 Bouvier...... 431/344 France Primary Examiner-Lloyd L. King 73 Assignee: S. T. DuPont, Paris, France Attorney, Agent, or Firm-Waters, Roditi, Schwartz & 22 Filed: Sept. 12, 1972 Nissen 21 ) Appl. No.: 288,396 57 ABSTRACT 30 Foreign Application Priority Data Apparatus for storing liquified gas under pressure in a Sept. 13, 1971 France...... 71.32946 container from which the liquid is released as a gas June 6, 1972 France...... 72.20346 into an atmosphere or region at a lower pressure than the storage pressure. This container additionally con 52 U.S. Cl...... 239/55 tains a solid on which the liquid acts like a 51) Int. Cl...... A24f 25/00, A61 l 9/04 swelling agent so that the polymer becomes a gel 58 Field of Search...... 239153-56; which releases the liquid stored therein as a gas. 43 1/344; 222/3 11 Claims, 7 Drawing Figures

f S s T

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3,813,041 2 APPARATUS FOR STORING A LIQUID FOR ETS An object of the present invention is to remedy these DISTRIBUTION IN THE GASEOUS STATE drawbacks by providing apparatus for storing a liquifia ble product in the liquid state with a view of its distribu The invention relates to apparatus for storing a tion is the gaseous state and make it possible to elimi liquifiable product in the liquid state, with a view to its 5 nate the auxiliary cut-off members for the gases. distribution in the gaseous state. According to the invention, there is provided a de Apparatus for distributing liquifiable products in the vice for storing a liquifiable product in the liquid state gaseous state are known. and for its distribution in the gaseous state into an at Depending on the vapor pressure of the liquid to be mosphere whose pressure is less than the storage pres distributed, very fine droplets of the liquid must be dis O sure, which device comprises a storage enclosure in persed in a jet of gas, under pressure for example. The tended to receive the liquid to be stored, at least one drawback of this distribution apparatus is the pressure part of which is occupied by a solid polymer with re which it requires. spect to which said liquid acts like a swelling solvent, The vapor pressure permitting, the gaseous distribu said enclosure communicating with at least one distri tion of the liquid can be sufficiently ensured by using 5 bution aperture. merely the gaseous air located at the top of the storage Certain liquid products act, with respect to certain enclosure. Depending on the desired distribution, it is , like swelling solvents, i.e., like solvents necessary that the outlet be provided with either a pres which cause the elastomer in question to swell, by act sure reducing device or with a device limiting the rate ing on the intermolecular connections (or "bridges') of flow, or with both. The main drawbacks of this man 20 between chains without causing the complete dissolu ner of storage and distribution is that the auxiliary tion of the polymer, the latter being, after the action of members considerably increase its cost price. said swelling solvent, in the form of a gel, but again This is why it has been proposed to provide the stor finding the integrality of its initial products after re age enclosure with a double chamber: a so-called stor moval of said liquid product. Polymers having this age chamber and a distribution chamber into which is 25 property have been previously described in the prior introduced a predetermined amount of liquid which va art and it is known that it is a question of polymers hav porizes therein before being distributed. However, this ing cross-links which, in the absence of these cross distribution method has the drawbacks of necessitating links would be soluble in the solvent in question but a device for determining the amount of liquid admitted which, due to these cross-links, swell and form gels into the distribution chamber, of being discontinuous 30 until the osmotic pressures balance the resilient ten and of resulting in a non-consistent distribution of each sions of the lattice. The bridges between the chains of vaporized amount and of reducing the volume available the polymers may be made by covalent connections, by for storage, due to the existance of the distribution ionic co-ordination connections by hydrogen connec chamber. tions or by crystallites. It has also been proposed to direct the liquid to its 35 The many tests carried out by the applicant have, distribution point by capillary means for example, by however, proved that, for a given liquid, stored accord means of a wick or a capillary tube. However, the draw ing to the present invention and intended to be distrib back of this means of distribution is that it necessitates, uted in the gaseous state, the polymers which can be in addition to a pressure reducing device and/or a de used must have a solubility parameter which differs at vice limiting the rate of flow, a transformation device 40 the maximum by 2.0 and preferably by it 0.5 from from the liquid to the gaseous state. that of the stored product in question. Moreover, the In another proposed solution, the liquid storage en temperature for transformation to the viscous state of closure is filled with a porous material such as cotton these polymers must be at the most equal to 50°C. or polyurethene . By capillary action, the porous Only polymers which fulfil this definition will there material keeps the liquid in its pores, which liquid is 45 fore be considered as lying within the scope of the in therefore never, in its liquid state, in contact with the vention, the present description and the claims which pressure reducing device, if there is one, or with the de will follow, vice limiting the rate of flow. This mode of distribution Thus, for example, polysiloxanes which have a solu is thus more advantageous, but it has the drawback of bility parameter of 7.3 can be used for storing liquified reducing the useful capacity of the storage enclosure, 50 butane, the solubility parameter of which is 6,75. The device according to the invention results in find Finally, it has been proposed to dispose, in the stor ings by the applicant during numerous tests which have age enclosure of the liquid, a polymeric foam with open proved that by placing, in the storage enclosure of a liq. cells, for example a polyurethene foam. As the liquified uified product and in conjunction therewith, a polymer, product is introduced under pressure, this foam is 55 with respect to which it acts like a swelling solvent, the soaked with liquid like a sponge and is also compressed gel obtained has the surprising property of releasing the . so that it acts mechanically, by elasticity, at the mo stored product only in its gaseous state at the moment ment when the product is distributed in the gaseous when it is distributed into an atmosphere whose pres state, the amount of product stored however remains sure is less than that of the storage enclosure. about the same as that which would be stored if a foam 60 A first advantage of the device according to the in with open cells was not being used, and contrary to vention lies in the fact that the presence of a gel in the statements by certain authors, a storage method of this. storage enclosure permits the use of the latter both as type does not make it possible to eliminate the auxiliary a stationary reservoir as well as a movable reservoir. cut-off apparatuses so that this storage method has A second advantage lies in the fact that the discharge never been used successfully in practise, for example 65 of the liquid in the entirely gaseous state makes it possi for supplying gas lighters from a reservoir of liquified ble to remove the devices intended to transform the fuel gas. fuel from its liquid to its gaseous state. 3,813,041 3 4 A third advantage relates to the amount of liquid fied fuel gas cartridges which cannot be refilled for gas which can be stored in a given reservoir. Indeed, tests lighters, for example). have been carried out by the applicant to determine the Various devices for carrying out the invention will liquified amount of gaseous hydrocarbons which could also be described in the following, but they will not be be stored, on the one hand in an empty reservoir and limitative. on the other hand in the same reservoir containing a porous material and thirdly in the same reservoir con EXAMPLE I taining a polymer according to the invention. These This example is intended to illustrate the fact that tests have proved that the device according to the in only polymers with weak transverse connections vention makes it possible to store greater quantities of 10 ("weakly linked polymers') may be used for carrying liquified products, all things being equal. out the invention. The storage device according to the invention has nu merous applications. Three types of polymers have been used for this pur A particularly important application relates to stored pose; on the one hand a without cross-links gas combustion devices such as lighters for smokers, 15 manufactured by the Shell Company, a polystyrene luminous gas lamps or gas heating apparatuses wherein with 2 percent cross-linking (beads sold under the com liquified hydrocarbons, particularly aliphatic hydrocar mercial name "IONAC") and poly-tert-butylstyrene bons such as butane, propane, pentrane or the like are with 0.025 percent cross-linking manufactured by the used individually or in combination as a fuel, these hy DOW Company and bearing the commercial name drocarbons having the property of causing certain poly 20 'MBIBER BEADD PR 171-71.' The tests have been mers to swell. carried out by dipping samples, for one day, in liquified Another application relates to the transportation, n-butane or in liquified pentane, greatly in excess. The over great distances, by vehicles provided with tanks or excess liquid has then been removed and the ratio of by ships of the type designed to carry liquified natural the weight of liquid absorbed by the polymer to the ini gas, of these liquified hydrocarbons the importance of 25 tial weight of the polymer (ratio designated by the ex which is becoming increasingly greater. pression "capacity of the polymer') was noted. Another application, always in the case of liquified The results obtained are illustrated in the following hydrocarbons, relates to the storage of these hydrocar Table . bons in vehicles with a combustion engine, with a view TABLE I to supplying these engines. In fact, it is known with ref 30 erence to the fight against atmospheric pollution that the liquified hydrocarbons tend to replace the liquid Polymer Test in n-butane Test in pentane Appear- Capacity Appear- Capacity hydrocarbons, the combustion of which results in much ance of of the ance of of the more harmful products (unburnt products, carbon 35 the polymer the polymer monoxide, etc.). polymer polymer Another application relating to other types of liqui Of-COSS linked dispersed 0.2 dispersed 0.0 fied compounds distributed in the gaseous state into the polystyrene ambient atmosphere, relates for example, to deodoriz Polystyrene unchanged 0.0 unchanged 0.0 ing products or insecticides. 40 with 2% appearance appearance COSS The numerous examples which will be described in linking the following description relate particularly to the case Poly-tert- Swelling 1.4 Swelling 20.0 of liquified hydrocarbons, which is very important as butyl-styrene (after 7 with 0.025% days) has just been indicated. This application, however, only COSS aims to illustrate the invention and must not be re 45 linking garded as limitative. However, it will be pointed out again that for liqui fied hydrocarbons stored in the liquid state with a view This table clearly shows that only polymers with a to their distribution in the gaseous state, the preferred low degree of cross-linking make it possible to store liq polymers which can be used are divided into seven 50 uified n-butane or liquified pentane efficiently. large classes of products, namely: polysiloxanes (so-called "polymers of silicons'); EXAMPLE II polyisoprenes, natural (latex) or synthetic; This example illustrates different ways of carrying polyolefins with transverse connections, obtained by out the invention with the polymers each belonging to action of radiation or peroxides; 55 the above-mentioned classes as capable of being used polyalkylstyrenes with cross-links; in the case where the stored liquid in a hydrocarbon in block polymers, at least one constituent part of which the liquid state. The following polymers have been has a maximum affinity for the solvent; used: polymethylpentenes; 1. Polysiloxanes: butyl rubber with weak links between the chains. la, foam with closed cells and having a low density The polymer used may be introduced into the storage manufactured by "Silicone Engineering Ltd." enclosure in the solid state. It may also possibly be po 2a. RTV foam (abbreviation of Room Temperature lymerized in the storage enclosure before it is filled Vulcanizing) 558; with the compound in the liquid state intended to be 2. Polyisoprene: distributed in the gaseous state. This latter modification 65 isoprene foam with closed cells manufactured by for carrying out the invention may be found to be ad Shell (commercial name Latex 700); vantageous for certain applications (formation of liqui 3. Polyolefins with cross-links: 3,813,041 5 6 3a. cross-linking by peroxide: manufac not been subjected to extraction and the same RTV tured by Sekisui, Japan (commercial name Softlon foam after extraction. This foam has been obtained BN-30). 3b. cross-linking under radiations: polyethylene man from commercialized products under the following ufactured by Furakawa Electric, Japan (commer- 5 aes: cial name: Minicel L-200); Rhodorsil 0558 4. Polyalkylstyrenes with cross-links: poly-tert Catalyst 10052 (14% by weight of the preceding) butylstyrene, manufactured by DOW (commercial Rhodorsil Oil Y-V-20 (% indicated above by weight name: Imbiber Bead XE-0 100.31) with 0.025% trans of Rhodorsil 10558). verse connections; 10 1. CAF 3THIXO 5. Block polymers: Characteristics of the polymer before absorption: olefin styrene manufactured by Shell, of the type of Extract the products "Kraton' of this Company (commer Weight: 100 g cial name GXT 0650). Apparent Volume: 97 cm 6. : 5 Shape: cylinders having a diameter of 6mm and a product sold by I.C.I. under the commercial name length of 20 mm. TPW RT 20. Swelling liquid presented (butane). 7. Butyl rubber with weak linking: product sold by Polysar Polymer Corp. Ltd., Canada, Weight: 300g under the commercial name Polysar Butyl XL. 20 Volume: 520 cm Tests for all these samples have been carried out by Characteristics of the polymer after absorption: dipping them for one day into liquified n-butane (ex Weight: 370g cept for sample No. 7 which was dipped in a mixture Apparent Volume: 565 cm comprising 20 percent by weight n-butane and 80 per Shape: substantially the same as that before ab cent by weight isobutane), or in liquified pentane. As 25 sorption. in example the excess liquid was removed and the ap Swelling liquid absorbed: pearance and capacity of the polymer was noted. The Weight: 270g results obtained are collected in the following Table II. Volume: 468cm 2. NOT EXTRACTED RTV FOAM. 30 TABLE II Characteristics of the solid polymer before absorp tion: Polymer Weight: 100g Sample Test in n-butane Test in pentane Apparent volume: 286 cm Appear- Capacity Appear- Capacity 35 Shape: Diabolos - large diameter of 12 mm; small ance of of the ance of of the the polymer the polymer diameter of 8 mm height 20 mm with "skin' on polymer polymer each base. la Swelling 9.0 b Swelling 7.0 Swelling liquid presented (butane): 2 Swelling 5.0 Weight: 400g 3a No Change 10.0 No change 1.5 40 3b Swelling 10.5 Swelling (35%) 10.2 Volume: 694 cm 4. Swelling 11.3 Swelling "T 16.0 Characteristics of the polymer after absorption: 5 Swelling 3.4 Geis 5.9 6 Swelling 1.7 - - - - Weight: 443g 7 Swelling 2.16 Apparent volume: 694 cm ------45 Shape: maximum swelling in the center. These tests aim only to illustrate the invention and Swelling liquid absorbed: are not limitative. On the contrary, the applicant has Weight: 343g carried out numerous tests, just as conclusive, on a Volume: 594 cm large number of compounds belonging to the various 50 3, EXTRACTED RTV FOAM aforementioned classes of polymers. Characteristics of the solid polymer before absorp In the ensuing examples, the operation, which con tion: sists of heating the polymer used, three times with ex Weight: 100g cess butane, until complete saturation, before it is used Apparent volume: 143 cm for storage, whether the liquid to be stored is butane or 55 Shape: Diabolos: large diameter 12mm, small di not, is termed "extraction'. Likewise, the treated poly ameter 8mm height 20 mm with “skin' on each mer is termed the "extracted' polymer. base. EXAMPLE III Swelling liquid presented (butane) This example relates to the case where the stored 60 Weight: 800g product is butane in the liquid state. Volume: 1,388 cm Three storage tests have been carried out, at 20°C Characteristics of solid product after absorption: and for 20 hours, with three different polymers respec Weight: 825g tively a CAF 3 THIXO (registered trademark, abbrevi Apparent Volume: 1,356 cm ation of "colle a froid") polymerized at 25°C for 24 65 Shape: maximum swelling in the center. hours, an RTV foam (abbreviation of Room Tempera Swelling liquid absorbed: ture Vulcanizing; rubber with silicon type) with 10 per Weight: 72.5g cent oil, polymerized at 150°C for 1 hour, which has Volume: 1,256 cm 3,813,041 7 8 EXAMPLE IV extraction, by the swelling liquid, of soluble matter This example relates to the case where the stored "present" in the polymer and which are usually added product is pentane in the liquid state. Three compara thereto to impart certain mechanical or chemical prop tive tests have been carried out with the same polymers erties thereto. Naturally, this preliminary extraction as in Example I, at 20°C and for 20 hours. 5 could be effected by a compound other than butane 1 CAF 3THXO and could comprise any numbder of successive absorp Characteristics of the solid polymer before absorp tions and deposits. tion: These examples also show the amount of liquid Extract stored varies depending on the polymer used and also Weight: 100g O on the structure of the polymer. In particular, it is as Apparent Volume: 98 cm certained that the rate of filling of a polymeric foam Shape: cylinder: diameter 6mm length 20mm with closed cells is always greater than that of a com Swelling liquid presented (pentane): pact elastomer. The applicant has also ascertained that macromolecular with closed cells have a second Weight: 200g 15 Volume: 319 cm advantage which is due to the fact that the liquid is ab sorbed and deposited more quickly than with a com Characteristics of the solid product after absorption: pact macromolecular compound. Weight: 227g In order to determine if the amount of liquid which Apparent volume: 301 cm can be stored in a given macromolecular product is an Shape: substantially the same as that before ab inverse function not only of the dimensions of the stor sorption. age container which may hinder swelling but also of Swelling liquid absorbed: stresses peculiar to its structure, two series of tests were Weight: 127g also carried out which were made from solid products Volume: 203 cm 25 of identical material, but whose outer characteristics 2. NOT EXTRACTED RTV FOAM were different. In the first case (Example V hereafter) the foam with closed cells which constituted the solid Characteristicstion: of the solid polymer before absorp products had each of its two bases constituted by a Weight: 100g "skin," i.e., from a plane surface, evidently less flexible Apparent Volume: 286 cm 30 than an alveolar surface, while in the second case (Ex Shape: diabolos: large diameter 12mm small diam ample VI) only one of its bases was constituted by a eter 8mm length 20 mm with "skin' on each skin, the other being constituted by an alveolar surface. base. Swelling liquid presented (pentane). Weight: 400g 35 EXAMPLE V Volume: 640 cm In this test, liquified butane was stored at 20°C for 20 hours, using the same RTV foam as in the preceding ex Characteristics of the solid product after absorption: amples. Weight: 400g The test conditions and results obtained were as fol Apparent volume: 580 cm 40 lows: Shape: maximum swelling in the center. Characteristics of the solid polymer before absorp Swelling liquid absorbed: tion: Weight: 300g Extract Volume: 480 cm Weight: 100g 3. EXTRACTED RTV FOAM 45 Apparent Volume: 143 cm Characteristics of the polymer before absorption: Shape: diabolos: large diameter 12mm small diam Weight: 100g eter 8mm height 20mm with "skin' on each Apparent Volume: 143 cm base. Shape: diabolos: large diameter 12mm small diam 50 Swelling liquid presented: eter 8mm length 20 mm with "skin' on each Weight: 800g base. Volume: 1,388 cm Swelling liquid presented (pentane) Weight: 600g Characteristics of the solid product after absorption: Volume: 959 cm Weight: 690g Characteristics of the solid product after absorption: 55 Apparent Volume: 1,122 cm Shape: maximum swelling in the center. Weight: 660g Swelling liquid absorbed: Apparent Volume: 993cm Weight: 590g Shape: maximum swelling in the center. Volume: 1,022 cm Swelling liquid absorbed: 60 Weight: 560g EXAMPLE VI Volume: 893 cm In this example a test was carried out which is exactly Examples III and IV clearly show the importance of the same as that of Example III, with the single differ the treatment byy "extraction' of the polymers used, be 65 ence that one of the bases of the solid polymer used had fore their application to the storage of liquids. The fact a skin while the other base was deprived of a skin. that after a first absorption, an increase in the absorp Using the same amount of butane as before, in the same tion rate of the polymers is noted, could be due to the conditions the following results were obtained: 3,813,041 9 10 Characteristics of the solid product after absorption: Duration of test: 20 hours The conditions and results of the test were as follows: Weight: 860g Apparent Volume: 1,417 cm Characteristics of the solid product before absorp Shape: maximum swelling between the center and tion: the base without skin. Not extracted Swelling liquid absorbed: Weight: 100g Weight: 760g Apparent volume: 107 cm Volume: 1,317 cm Shape: circular rings: The comparison of these results with those of Exam O outer diameter: 10mm ple V reveals the fact that the amount of liquid which inner diameter: 3mm can be stored by the process according to the invention thickness: 3mm is directly related to the structure of the solid polymer Swelling liquid presented: used for carrying out this process. Weight: 200g Other tests carried out by the applicant for the same 15 Volume: 303 cm purpose have also proved that, for the same solid poly Characteristics of the solid product after absorption: mer used, the amount of liquid stored depends on the sum of the volumes of the alveoles per unit of apparent Weight 270g volume. Apparent volume: 364 cm Various tests, intended to illustrate the various ways 20 Shape: substantially the same as before absorption. of carrying out the invention, will now be described in the following examples, which are not limitative. These Swelling liquid absorbed: examples do not relate merely to the storage, in the liq Weight: 170g uid state, of compounds intended to be distributed in Volume: 257 cm the gaseous state into the same temperature conditions, 25 but also to the conditioning of products (normally liq EXAMPLE IX uid) at the temperature in question and consequently Polymer used: CAF 3 THIXO (registered trademark; intended to be distributed in the liquid state. Indeed, product similar to that described in the preceding ex these tests give valuable information about the function amples) of the solid polymer used in the framework of the in 30 Swelling solvent (product stored) ; hexane vention. Moreover, they prove that, at the limit, the Temperature of the test : 20°C process described in the main patent may also be ap Duration of the test : 20 hours plied to the storage of liquid products intended to be The conditions of the test and the results obtained distributed in the liquid state by increasing the pressure are as follows: inside the enclosure. 35 Characteristics of the solid product before absorp tion: EXAMPLE VII Extracted Solid polymer used: Viton (registered trademark; a Weight: 100g fluoric elastomer having as a base the copolymer of flu Apparent volume: 97cm oride of vinylidene and of hexafluoropropylene). 40 Shape: cylinder: diameter 6mm; length 20mm Product stored : acetone Swelling liquid presented: Storage temperature : 20°C Weight: 300g Duration of storage : 20 hours. Volume: 455 cm The conditions and results of this test were as follows: 45 Characteristics of the solid product after absorption: Characteristics of the solid product before absorp Weight:368g tion: Apparent volume: 504 cm Not extracted: Shape: substantially the same as that before ab Weight: 200g sorption. Apparent volume: 109 cm 50 Swelling liquid absorbed: Shape: smallplate: length 20 mm width 20 mm Weight: 268g thickness 1 mm Volume: 407 cm Swelling liquid presented: Weight: 200 g EXAMPLE X Volume: 253 cm 55 Polymer used: natural rubber Characteristics of solid product after absorption: Swelling solvent (Liquid stored) : pentane Weight: 324g Temperature of the test: 20°C Apparent volume - 266 cm Duration of the test: 20 hours. Shape: swelling in thickness 60 The conditions of this test and the results obtained Swelling liquid absorbed: are as follows: . Weight: 124g Characteristics of the solid product before absorp Volume: 157 cm tion: Not extracted EXAMPLE VIII Weight: 100g Solid polymer used: natural rubber 65 Apparent volume: 108 cm Swelling solvent stored: hexane Shape: circular rings: Temperature of the test: 20°C outer diameter: 10mm 3,813,041 11 12 inner diameter: 3mm Weight: 330g thickness: 3mm Swelling liquid presented: Volume: 202 cm Weight: 100g The above examples clearly show the various poly mers which can be used in various physical forms, and Volume: 160 cm 5 the numerous applications of the process according to Characteristics of the solid product after absorption: the invention both to the storage of liquified products Weight: 163g and products normally liquid at ambient temperatures. Apparent volume: 208 cm As has already been emphasized, one of the most im Shape: substantially the same as that before ab- 10 portant and most advantageous applications of the pro sorption. cess according to the invention relates to liquified fuel Swelling liquid absorbed: gases, in particular liquified, gaseous aliphatic hydro Weight: 63g carbons. Volume: 100 cm In this application, the storage device according to EXAMPLE X 15 the invention has surprising advantages which were not Solid polymer: CAF 4THIXO evident to the man skilled in the art. These advantages Swelling solvent: butane will now be revealed. Temperature of the test: 20°C Firstly, it is evident that the process according to the Duration of the test: 20 hours. 2O invention retains the advantages of processes for stor The conditions of the test and the results obtained ing liquids with spongy supports, namely stabilization are as follows: of the stored liquid and possiblity of using the storage Characteristics of the solid product before absorp container in any position whatsoever. t1On: With respect to known apparatus, the apparatus ac Not extracted 25 cording to the invention also has the advantage of im Weight: 100g proving the checking of the distribution, which in the Apparent volume: 91 cm caseexplosion. of easily combustible liquids, reduces the risks of Shape: cylinder: diameter 6mm; length 20mm Swelling liquid presented: In order to illustrate the improvement made by the Weight: 200g 30 invention, a certain number of tests have been initiated of the combustion of butane either alone, or stored in Volume: 347 cm with open cells, or stored in cotton, or Characteristics of the solid product after absorption: stored in RTV elastomer foams with closed cells or fi Weight: 250g nally stored in elastomers of the CAF series. Apparent volume 351 cm 35 All these tests were effected in the open air. During Shape: substantially the same as that before ab each test, the combustion of the same amount of bu sorption. tane was initiated. The supports used all had a thick ness of 1cm and had, at the beginning of the test, the Swelling liquid absorbed: same evaporation surface as the free butane. Weight: 150g In these conditions, the results expressed as coeffici Volume: 260 cm 40 ent of combustion duration were as follows: EXAMPLE XII butane alone: 1.0; Solid polymer: natural rubber butane stored in polyurethene foam with open cells: Swelling solvent: carbon sulphate 1.4, 45 butane stored in cotton: 1.9; Temperature of the test: 20°C butane stored in RTV elastomer foam with closed Duration of the test: 20 hours cells: 2.5; The conditions of the test and the results obtained are as follows: butane stored in compact elastomer of the CAF se Characteristics of the solid product before absorp ries: 3.0. tion: 50 A second advantage made by the invention lies in the Not extracted fact that the pressure of the gaseous air above the liquid Weight: 100g stored in the storage container is less than that of the Apparent volume: 107 cm gaseous air in a container with liquified gas alone or in Shape: circular rings: a container with gas and cotton or gas and alveolar outer diameter: 10mm 55 foam with open cells. inner diameter: 3mm The tests which have been carried out to illustrate thickness: 3mm this point have been greatly influenced by the variables Swelling liquid presented: which could not be exactly identified (probably varia Weight: 400g tions in composition both of liquids and elastomers). 60 Nevertheless, even if the favorable results which can Volume: 31 7cm . not be reproduced are excluded to retain only the aver Characteristics of the solid product after absorption: age values of the results obtained, it is established that the device according to the invention is found to be Weight: 430g very superior to the conventional devices. This is Apparent volume: 309 cm 65 proved by the following numbers which relate to the Shape: substantially the same as that before ab value, in bars, at a temperature of 25°C, of the relative sorption pressure of the gaseous air in a storage container con Swelling liquid absorbed: taining a mixture of liquified hydrocarbons comprising 3,813,041 3 4. (in 96 by weight) 79.0% n-butane, 19.0% isobutane, tainer. The chamber 1 which may be filled with liqui 1.0% propane, 0.5% ethane and 0.5% pentane and bu fied gas by a valve 16 has a much greater volume than tene: in the case of the embodiment shown in FIG. 2, with this mixture alone: 1.65 whereas the chamber 2 has a minimum volume in with this mixture and a polyurethene foam with open communication with the distribution aperture 17. The cells: - 1.65 membrane 4 ensures a continuous distribution of gas, with this mixture and a cotton: 1.65 releasing the latter through the face located opposite with this mixture and an RTV elastomer foam with the aperture 17, whereas through the opposite face, it closed cells: 1.51 absorbs an amount of liquified gas which may or may with this mixture and a compact CAF elastomer: 1.45 10 not be equal to the amount of gas released. FIG. 4 is a detail view of a modification of the device It is to be noted that the tests carried out by the appli of FIG. 3, wherein the elastomeric membrane 4a cant have proved that the difference between the gase surrounds the grid 13.a. ous air pressures in the apparatus according to the in In the embodiment according to FIG. 5, the hollow vention and in conventional apparatus is more accentu 5 body 8 comprises a main chamber 19 which can be ated for containers with a leakage having a constant filled with liquified gas by the valve 20. The liquified cross-section. gas impregnates a polymeric material which fills a tubu Finally, in the application of the means according to lar member 21 made of gridding and connected to the the invention to the storage of liquified fuel gases in distribution aperture 22. tended to supply a combustion means, an extremely im 20 As shown in FIG. 7, the tubular element 21 made of portant advantage lies in the fact that the combustion gridding, may be replaced by a tube 23 of any material device can be supplied directly without the interposi containing no polymer, but having perforations closed tion of a device for transformation from the liquid to by a suitable macromolecular material 24. the vapor state. Finally, in the modification according to FIG. 6, the Another advantage peculiar to this application is due 25 storage enclosure 25 comprises no more than one sin to the fact that the device limiting the rate of flow may gle chamber 26, whose inner walls, with the exception be removed, which is usually mounted on the supply of the part adjacent the filling aperture 27, are covered line of the combustion device so as to keep only a regu with a layer 28 of a solid polymer so as to form a kind lating device at the users disposal. of pocket which receives the liquid by way of the aper The accompanying drawings given merely by way of 30 ture 27, the gas being released directly through the a non-limiting example, illustrate various embodiments membrane 28 on a level with the distribution aperture of an enclosure for storing a liquified fuel gas utilizing 29. these advantages of the storage process according to When a storage chamber of the type which has just the invention. In these drawings: been described is intended to supply a gas combustion FIG. 1 is a vertical section showing a first embodi 35 device, it may be made integral with the device and ment according to the invention; may be filled with liquified gas either directly by way FIGS. 2, 3, 5 and 6 are respectively views similar to of the filling aperture or by means of a "refill' consti FIG. 1 of four variations, and tuted by an element of a macromolecular product hav FIG. 4 and 7 are detail views illustrating other varia ing a suitable shape and volume, and previously satu tions. 40 rated with liquified gas. Detachable enclosures may In the embodiment shown in FIG. 1, a hollow body also be used constituting disposable refills. 1, which cannot be refilled, contains a plurality of What is claimed is: pieces 2 of a solid elastomer with respect to which the 1. A device for storing a liquefiable product in the liquified fuel gas to be stored acts like a swelling sol liquid state with a view to its distribution in the gaseous vent. An aperture 3 formed at the top of the body 1 45 state, comprising a storage enclosure, at least one part makes it possible to supply a burner with fuel gas with of which is occupied by a solid polymer with respect to out the interposition of a cut-off system. which the liquid to be stored acts like a swelling sol In the modification, according to FIG. 2, the hollow vent, this part of the enclosure communicating with body 4 is divided into two separate chambers 5 and 6 one or more distribution apertures, said polymer being respectively by a grid, latticework or more usually a 50 absorbative of the liquefied gas and having a limited support 7 provided with apertures, secured in the body solubility parameter with respect to said liquefied gas 1 and through which communication between the two so as to undergo swelling and form a gel which releases chambers is effected. A filling valve 8 provided in the the liquid only in gaseous state. base of the body 4 makes it possible to fill the chamber 2. A device according to claim 1, in which said poly 5 with a liquified fuel gas, the liquid passing through the 55 mer comprises a membrane covering at least one part support 7 so as to impregnate a solid polymeric mate of the inner walls of the storage enclosure. rial contained in the chamber 6. A burner (not shown) 3. A device, according to claim 1, in which said poly is supplied with fuel gas by way of the aperture 9 mer comprises a membrane interposed between the formed at the top of the body 4. 60 stored liquid and said one or more distribution aper The embodiment according to FIG. 3 is derived di tureS. rectly from that of FIG. 2. The hollow body 10 is di 4. A device according to claim 1, comprising a tubu vided into two chambers 11 and 12 by a grid 13 or the lar member connected to said one or more distribution like, however, the elastomer intended to be impreg apertures, said tubular member having at least one ap nated with liquified gas is constituted by a simple mem erture closed by said polymer. brane 14 held against the grid 13 by a ring 15 force fit 65 5. A device according to claim 1, wherein said poly ted into an inner groove of the body 1, the grid itself mer is polymerized "in situ' in the storage enclosure bearing against a shoulder of the inner walls of the con prior to being filled with the liquid to be stored. 3,813,041 15 16 6. A gas lighter, in which ignition means and combus tion means for the gas is supplied by a device according 8. A device according to claim 1 wherein said poly to claim 1 without the interposition of a member ensur mer is weakly cross-linked. ing the cutting off of the gas. 9. A device according to claim 1 wherein the solubil 7. A device according to claim 1, in which the liquid 5 ity parameter of the polymer differs at most from the to be stored comprises a major part of at least one liq liquefied gas by E2.0. uefied saturated hydrocarbon and the solid polymer is 10. A device according to claim 1 wherein the solu selected from the group consisting of polysiloxanes; bility parameter of the polymer differs at most from the natural polyisoprenes; synethtic polyisoprenes; poly liquefied gas by it 0.5. olefins with cross-links, obtained by action of radiation 10 11. A device according to claim 1 wherein said distri or peroxides; polyalkylstyrenes, with cross-links; block bution aperture of the storage enclosure is adapted for polymers having at least one constituent part with a direct communication with ignition means and com maximum affinity for the solvent; polymethylpentenes; bustion means for the gaseous product. and butyl rubbers with weak bridging between chains. k k. k. xk sk 15

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