US1596671A

US1596671A - Method and apparatus for impregnating fabrics

Info

Publication number: US1596671A
Application number: US490495A
Authority: US
Inventors: Lionne Ernest
Original assignee: Individual
Current assignee: Individual
Priority date: 1921-08-06
Filing date: 1921-08-06
Publication date: 1926-08-17
Anticipated expiration: 1943-08-17

Description

Aug. 17 9 1926.

E. LIONNE umuon AND APPARATUS FOR rurnssmrmc names I 5 Sheen-Shoot 1 Filed August 6, 1921 E. LIONNE METHOD AND APPARATUS FOR IMPREGNA'IING FABRICS Aug. 17 1926.

Filed August 5, 1921 5 Shoots-Sheet 5 z I 2 F gig/ Aug. 17 1926. 1,596,671

. E. LIONNE METHOD AND, APPARATUS FOR IMPREGNATING FABRICS Filed Aug e, 1921 5 Sheets-Shoot 4.

Au 411 192s. I 1,596,671

E. LIONNE H ETHOD AND APPARATUS FOR IHPREGNATIYIQ FABRICS Filed August 1921- u shuts-sun s Patented Aug. 1?, 1926. v

UNITED STATES PATENT O FICE.

u moms, or nnnnmm arrears unssscnusnrrs I METHOD AND hummus non imrnnenatrrue sums.

Application filed Aug 'ust fi, 1921. Serial No. 480,495.

This invention relates to appar atu s fori impregnating" webs of fabric and the like wherein the material finally is impre nated' with the solidified cellulosic materia from which the solvents have been removed and the solidified cellulosic material is madeartificiallyporous whereby the treated textile material is fluid permeable and, while be practically instantaneously softened by the application of a suitable softening agent which will permeate the entire body of the prepared material by assinginto the artifi ciial pores of the soli ified cellulosic materia .v

In carrying out the above object of the" invention, the textile material is impregnated. with the preferably cellulosic solution chamber is maintained at a temperature practically equal to or, and preferably, above the boiling point of the solvent and'the chamber is adapted substantially to be filledwith solvent vapor with a minimum amount'of air.

Due to the elevated temperature and satu- 40 rated solvent vapor in contact with the impregnated web,- the entire solutionimpre nating the web dries pra'cticall' uniform y and minute solvent. vapor .bu bles rising throngh' the solution from the interior'thereof and bursting through the surface leave minute passages or pores which. remain when the evaporation of-the solventvapor is complated and thecellulosic material is dry and result in the formation of a structure which is fluidpermeable by reason ofhaving minute poresinit. J Y

7 i The invention comprehends, a further object, an impregnating or saturating device through which the web is passedto be impregnated with the solution; 'a drying chamber through which the wet impregnated web ispassed to-be dried; and a solvent re covery apparatus to condense thesolvent vapor a stracted from the "solution in the web;

tlOIl. '1 v 9 A further object "of the invention is to pro vide an impregnating device especially ary and all correlated to fuiiction in combine ranged"thoroughly to impregnate thick por-4 ous materialsin the web, as felt and the like.

Another object is to provide .a drying chamber in which the, wet impregnated-web may be dried rapidly to producethe product above set forth.

A further object is to provide a solvent re;-

' covery apparatus arran ed to handle the 1131- normally relatively stiff and inflexible may atively large amount 0 solvent vapors coni tained in the impregnating solution and condense the vapors andrecover a relatively high proportion of the solvent.- 1

Coating and solvent recovery-apparatus are used in the manufactureqof artificial leather-,ior instance ratus of the present. inventionis particu arly designed; p p In I artificial leather "making, .for instance, the'fabric body is subjected to repeated 8 ,pli'cations of the'coatin'g substancezandt e coating is driedbefore the application of a further coat and. the amount of coatin I a plied for each layer'i-s relativelys'ma iii the impregnating of a material such as felt with .an imperg'na'ting solution, however,

but, by reason of the great differences" in the method of treatment" of the fabric and the amount of coatingsolution employed as compared to the resent in and then passed into a drying chamber wherein the volatile solvents are evaporated from' the impregnated web. The. drying conditions are essentially diffierent. ,The en tire quantity of solution is applied-in one operation to the material, as contrasted with the several operations in the ooating'method.

The quantity of solution employ for. im-

pregnating the, material varies with the character, as thickness and porosity?- of the material to be impregnated, whereas, the amount oft-eating solution, except fpomibly for the first layer, is independent 0 the nature of the material. For satisfactory results, the impregnation must be rformed in a single passage of the web 0 material through the im regnating device and dryin chamber. (ibnsequently, the amount of sofvent vapor that must be evaporated from the. impregnated material in the dryin chamber is relatively great as contraste with the usual coatin (process and especial means must be provicfi; to effect the eve oration and subsequent 'recove of the so vent. The usual types of drying chamber and solvent recove apparatus employed for the coating of abrics can not handle this large amount of solvent effectively; and a combination of impregnating. apparatus, drying chamber and solvent recovery apparatus to impregnate materials with and abstract and recover the volatile solvents from, such large amounts of impregnating solution is an object of this invention.

A further object is generally to improve the construction and operation of impregnating and solvent recovery apparatus.

The product made in accordancewith the process herein disclosed is claimed in my atent No. 1,514,548, granted Nov. 4, 1924. Fig. 1 is 'a diagrammatic representation of the impregnating and solvent recovery apparatus embodying the invention. ig. 2 is an enlarged longitudinal section through the im regnating device.

Fi. 3 is a plan view of the impregnatevice of Fig. 2 with the cover removed. i 4 is an end detail of the im regnat= ing evice, partly in section, and 1 lustrating ing more particularly the means for auto-.

matically maintaining a constan'; level of solution in the device.

Fig. 5 is a section taken along line 5-5 of Fig.3.

Fig. 6 is-a section taken along line 6-'6 of Fig. 3.

Fig. 7 is a detail illustrating the bearing support for a pair of superimposed pres sure rolls.

Fig. 8 is a longitudinal sectional elevation of the drying chamber.

Fig. 9 is a section along line 99 of Fig. 8.

Figs. 10 and 11 are front and sectional elevation details of the entrance slot of the drying chamber.

i 12 is a sectional view of the novel artic e made in accordance with this invention.

.As here shown the impre ating and solvent recovery apparatus inc ude the impregnating device 15, the drying chamber 16 and. solvent recovery apparatus associated with said drying chamber and of which said drying chamber forms an integral part.

The web of material 17, as felt, is supported on the shaft 18 in front of the impregnating device. The web is passed over the idler roll 19 disposed above the impre nating device and down into and throug said device and becomes thoroughly impregnated or saturated with the impregnating solution. The impregnated web is then passed into the drying chamber 16, preferably without passing over any intermediate supporting rolls, and becomes dried by evaporation of the volatile solvents from the wet web, and thence is passed out of the drying chamber and over the guide roll 20 and is wound into a roll on the winding shaft 21; and said winding shaft may be suitably driven in any well known manner, not

necessarily shown.

It will be noted that the web is adapted to be passed but once through the impregnating and drying apparatus to become saturate and dried, and a relatively large amount of'solution is taken up by the web as contrasted with the usual coating machine wherein but a relatively small amount of solution is applied to the web at one coating operation and the web must be assed through the coatin machine a pluraii times for the a plication of a coating of the required thiclm ss The impre ating device comprises a tank 22 of vs'uitabi shape and dimensions to receive the web; and said tank is adapted to contain rolls which act upon the web to effect the thorough saturation-thereof with the impregnating solution; and the driving apparatus for said rolls. Said tank is provided with a removable cover 23 formed.

with an entrance slot 24 throu h which the web is passed. A plurality of pairs of superimposed rolls, each pair comprising atop or pressure roll25, and a lower or driving roll 26, are disposed in spaced relation preferably in a horizontal line in the tank and are adapted to be below the level of the impregnating solution in the tank. Said rolls are formed at each end with reduced or bearing-

portions

25 and 26 which are retatably receivedin vertical slots 27 in the, preferably, wooden bearing members 28 arranged at the opposite sides of the tank. Said lower rolls 26 rest in the bottom of said slots and the upper rolls are adapted to rest upon and be rotated by the web passed between the rolls and the side walls of the slots serve to restrain said upper rolls against displacement in the direction of the moving we 1 Each pair .of rolls is arranged to serve as a driving element for the web, in addition to its function of eifecting the therough im regnation of the web as is hereinafter to e' described, and all lower rolls'are adapted independently to be driven positively at equal speeds whereby to etfect the movement of the web through the impreg- I nating device.

with the gears 30 of said shaft. It is chvious thatas said shaft is rotated, all of said rolls will also be rotated positively, and, as all sets of gears are identical, all rolls will be rotated at equal ed. A pulley 32, see Fig. 5, is secured to t e bearing-portion of an intermediate roll 26 and is drawn by a belt from some suitable external power source, as the pulley32", Fig. 1, whereby to drive the driving shaft through a pair of said gears and 31. I

Said rolls and driving mechanism. is

' adapted to be submerged in the impregnating'solution and lubrication of the movingparts is efiected by the solution.

The web is adapted to be passed under the surface of the solution in the tank and through the pairs of rolls. Said upper rolls are adapted to be relatively heavy whereby to effect a considerable pressure upon and compress the web and hold it in driving engagement with the lower rolls. Said lowerrolls are adapted to move the web through the solution. 1

The arrangement of rolls is an important feature of the invention and said rolls serve to provide a series of alternate compres' sions and subsequent releases of the loosely formed Web while submerged in the solution, whereby to effect the thorough satura' tion of the web with the solution.

As the loosel i formed web passes downward into the bight of the first pair of rolls it may contain a relatively large amount of air which, if not forced out, may prevent access of the solution to the interstices, and the thorough saturation, of the web. Said first pair of rolls acts to compress the web and force out a large portion of the air in front of the rolls. As the web passes from the bight of the rolls, the pressure is released. The material. of the web tends to return to its original position and solution is forced into the interstices of the web by atmospheric pressure andthe weight of the solution. As the web passes into the bight of'the second pair of rolls, the solution al.

ready in the web is forced to penetrate the web yet further and any remaining entrapped air is forced out. As the web leaves the bight of the second pair of rolls, the compression pressure is released and further solution is forced into the web. Thisaction continues in successive pair of rolls and when the web passes from the last air of rolls of the series it will be thoroug y impregnated with solution.

The number of pairs of rolls will vary with the nature of the web and the solution and, obviously, a thick web and solution rolls. than a thin web, and thin. solution.

The web passes from the, last pair of rolls of the series u wardly through a scraping and squeezing evice and thence through the Exit slot 35 in the tank to the drying cham-. er. v

The scraping and squeezing device maycomprise any suitable means and, as here shown, includes the stationary bar 36 having may require a larger number of pairs of a curved web-engaging face etxended trans versely beneath the web in front of the exit slot. A'weighted pressure bar 37 having a correspondingly-shaped lower face is disof the tank. The weight of said pressurebar 37 is adapted to press the web between it and the lower bar 26 and, as said web passes therebetwee-n, surplus im regnating solution will be removed from t e surface and interior of the web and drain back into the tank.

vice and above the level of the solutions therein. Said tank is provided-with an open neck 41 in its bottom which extends within a lower receptacle 42 adapted to be incommunication with the atmosphere and which is adapted normally to be filled with the impregnating solution to a level sufiiciently above the mouth of the neck to seal the neck and prevent a flow of solution from the elevated'tank 40. Said receptacle 42 is connected by the pipe 43 to the impregnating device; and the level of solution in said receptacle 41 is adapted to be substantially the same as in the impregnating device. It is obvious that solution will flow from said receptacle 42 to the impregnating device to compensate for that taken up by the web and when the solution level in the receptacle descends to uncover said neck air will be admitted to the tank 40 and solution will flow into the receptacle 42 to restore the fluid level therein.

I Said tank 40 may be provided with a constant the level of imposed above the web and is pivoted to the rod 38 which is supported in side members sight gage 44 and when the solution in said tank is ow an operative will open a'valve 45 in a pipe 46 to admit solution therein from a supply tank 47 which preferably is "under elevated air pressure.

Said receptacle 42 and impregnating de vice are provided with drain-

oil pipes

48 and 49 through which solution may be drained back into the supply tank when the air pressure in said tank is relieved.

The wet impregnated web is passed from the impregnating device into the drying chamber 16 through the entrance slot 55. To prevent loss of solvent vapor from the wet web in its passage to the drying cham- 'ber the web is enclosed in a closed box 56 which extends between and is in communication with said slots and incloses the wet web; andisald box may be provided with a removable cover 57 adapted to be removed atmosphere through the entrance slot and exit slot 62. I Said meansincludes the sets of plates 63' and 64 adjustably disposed above and below each slot and having the ends thereof formed with elongated slots 65- with wing nuts 67 are through which clamping bolts 66 provided passed. Relatively thick sheets of flexible material 68,;as felt,

are clamped removably between the plates of each set b the bolts 69 and project over in front of t e slot. The web is ada ted to.

be passed between and in substantial y gastight contact with said upper and lower strips. The extended portions of said strips are relatively flexible'whereby to yield and maintain contact-with the moving web. Ad-. justmentsof said stripsto take up wear and maintain good on gement with the web may be made by a justing said sets'of plates vertically.

In the drying chamber the wet web is passed over a roll 70 adjacent the entrance slot 55 and thence ufwardly over the first one of a series 0 horizontally aligned, spaced upper rolls 71. A series of horizontally-aligned, spaced rolls 72 are disposed in the lower portion of the drying chamber and are preferably intermedial y spaced relative to the upper rolls. The web 1s threaded alternately over an u per roll 71 and thence about a lower roll 2 and again over an upper roll and so on, assing substantially vertically between sai rolls and finally passing; in dried condition, through the and onto the winding shaft 21.

exit slot 62 over the external guide roll 20 All of said

rolls

70, 71 and 72 are positively driven whereby to pass ,the web through the drying chamber with the minimum of stretch. The driving means includes the horizontal shaft 74 disposed beneath and at one end of the up er set of rollers 71 and extended beyond the drying chamber for connection with a suitable power source by means of the pulley 75 or equivalent. Saidshaft is provided with a plurality of worms 7 6 and-each of said rolls 1 is provided with a worm gear 77 which meshes with its corresponding worm and by which it is driven positivel A similar horizontal shaft 78 is dispose in the lower portion of the drying chamber above and at one end of the lower set of rolls 72 and worms 79 carried by said shaft mesh with worm gears 80 of said rolls. 'A vertical I ,shaft 81 connects said upper and lower shafts through the mitre gears 82 and 83 for rotation at equal speeds and a worm 84 on said vertical shaft meshes with a. worm gear 84" carried by said roll 70 to provide positive driving means for said roll. All of said worms and worm gears are so arranged. that the peripheral .s eed of all rolls is the same wherebythe we will be driven with cultl strain between, or slippage on, adjacent ro s.

Pressure rolls 85 are disposed to bear upon the partially dry web as it passes over one or more of the upper rear rolls 71- ance. cally-disposed guide assages 86 formed by the angle-irons 87 an are free to move vertically in said-pamages.

The wet web is ada ted to be heated to an elevated temperature y heatin coils 'where-= by to evaporate the solvent om the impregnating solution and dry the web; and verticall -arranged heating coils 90 and 91 may be isposed within the chamber adjacent the sidewalls thereof, and a horizontallyarranged heating coil 92 may be disposed in the lower part of the chamber below the the pipes of said coils are ground joints whereby toreduce the probabili of steam g "chem r which woul ultimately require distillation to separate the :water from the li uefied solvent. Apertures 94 areformed in t ewalls of the leaka into the "d chamber'to admit the passage of circulating pipes to said coils and said apertures about i said pipes are adapted to be substantially 1257 gas tight to avoid eakage from. or to said chamber.

A door 95 is provided at the rear wall of i the chamber to admit an operativewithin' the chamber and said door will be sealed whereby to calender the surface of the web Y and improve its surfacefinish and appearaid rolls are supported in vertilower rolls 72. Preferably the joints '93 in v necessarily shown, whereby to reduce heatwith the drying of a purely coated mautee ezsr or two of said sets of

rolls

71 and 72 to lubricate them to avoid the adherency of the wet web thereto; and other doors may be provided to ermit access toother parts of 1 the dr ing 0 amben.

- If esired, he'd ing chamber may be enclosed in a' heat-insulating casing, not

losses through the walls of the chamber.

' The solvent vapor within the drying chamber is adapted to be substantially at atmospheric'pressure and the solvent recovery apparatus, hereinafter to bedescribed, is adapted to cooperatewith the heating coils to remove. and condense the vapor subs'tantially as fast as vapor is formed whereequal to atmospheric 4 pheric is built up by to maintain a pressure substantially ressure within said chamber. A loaded 0 eck valve 98 is in communication with the interior of the chamber and is adapted to open outwardly if a dangerous pressure greater than atmoswithin the chamber by any cause, where y to relieve the pressure; and an inwardly-opening check valve 99 is arranged to admit air to the chamber if a' dangerous within the c amber, whereby to prevent collapse of the walls thereof.

A blower 100 is connected with the chamher and is adapted-to be operated if the solvent recovery apparatus becomes ineffestive to remove the solvent vapor whereby to permit the impregnating and drying up paratus to continue to operate temporarily. An appreciable amount of solvent vapor may condense within the drying chamber and will collect on "the bottom wall 61 Said wall is pitched toward the middle and communicates with a drain pipe 102 to conduct the condensate to a' storage tank 103; and said pipe may have a valve 104 therein.

The drying chamber above described ,is an important feature ofthe invention.

The temperature within the chamber is adapted to be maintained by the heating coils about at or preferably above the boil-P ing point of the solvent employed in the impregnating solution. It several solvents are employed they preferably will be selected to have about the same boiling points and if'the solvents difier substantially in boiling points the temperature otthe drying chamber will preferably be near or above that of the solvent having the most elevated boiling point. An elevated temperature,

while desirable to promote rapid evapora tion of'the solvent vapor from the irnprag I nated web is especially advantageous in pre paring the desired porous cellulosic impregnated product. The drying chamber is artial vacuum should exist Y adapted to be filled with solvent vapor and with as small as practicable amount of air. As the temperature is practically that "of the boiling point of the solvent, solventvapor bubbles will rise from the interiorof the impregnated web and burst through the surface and leave minute channels or'pores in the material. -As the chamber is filled with saturated solvent vapor'there is little tendency for the outer surface of the ma terial "to dry or'solidify first, asis the case terial in the usual drying chamber, and the material will dry practically: uniformly.

throughout its body.

As the solution becomes and nenfluid the channels or pores by the escaping vapor bubbles remain open'and when the material is thoroughly dry'it will be found to be porous'and fluid. permeablefand cathereon by the process.

The solvent recovery apparatus is an im portant component of the impregnating and drying apparatus and is arranged tohandle and condense the relatively great volume of solvent vapor contained in the web as it is passed from the im legnating device through the drying chamher.

Means are provided stages. In the first stage the vapor is cooled at substantially atmosphereic pressure and to condense t me 'tively high proportion of the solvent vapor temperature and some of the vapor is con densed. The cooled gas and uncondensed vapor is then strongly compressed and;

cooled at the elevated flpressure and afurther condensation is e ected, The remaining vapor is then subjected to-refrigeration.

' in previous solvent recovery ap aratus, refrigeration has been wggested' as t e final stageof solvent recovery and independent apparatus has'been utilized to refrigerate lit? a cooling medium as brine and circulate the cold brine inv heat-transferring relation with the solvent vapor, adds to the cost and complexity of. vent recovery apparatus. 1 c

It is an important ob'ect of this invention to utilizetheenergy o the compressed gas;

and vapor to produce a reduced temperature which will be effective in condensingjthe larger part of thefinal solvent vapor; and

pandin the cooled vapor and gas' fromits elevated pressure to a lower and substan- Such apparatus: the sol:

the reduced temperature'isattained by .'ex-.-

' tially atmospheric 'ressure; and preferably 1 struction. -Gooling water,

' .Water is circulated by the ge tank 120-. "is

utilizin the expan 'ng gas and-vapor to do work whereby the reduction in tem rature of the gas and vapor is enhan Fur:

thermorethe energy liberated may be used in supplying power to operate components of theapparatus. 1 Fig. '1 illustrates diagrammatically the solvent recovery apparatus embody ng the invention. a

tively small volume of air, and both at substantially atmospheric pressure, are drawn through a pipe 110 from the lower part of the drying chamber and through a condenser 111 into the compressor 112. Said condenser may be of more or less common conor other cooling medium, is adapted to enter thecondens'er through the pipe'113 an'd flow-upwardly in a direction contrary-to the flow of vapor i and gas and pas from the condenser through the pipe 114; A-"cooling and partial condensation of the. solvent vapor will take place in the condensator' which consti-.

tutes the first-stage of thesolvent recovery apparatus, and the condensate is adapted to pass through the pipe 115 to the drain pipe 102 and thence into the storage tank 103. The cooled gas and vapor are drawn from the. condenser into the preferablg cooled compressor 112, which may e in any suitable manner, andheated comprewed gas and vapor ispassed into a condenser 116 through which cooling The gas and vapor is cooled substantially to the temperature of the cooling water in saidcondenser, and without substantial reducmuch as the "solvent in the storage tank 103" may be at substantially-atmospheric pressure andjthe pressure ,within the condenser 116 is greater than that of the atmosphere, the condensed: solven t preferably is discharged through'said pipgllQ to an auxiliary stor odl 11 d1 h m 'Whg0h;'t%11e-hS0lVpnt is.

i ca y se argedt roug t epipe 121: 1 l t 0 thesto e tank 103.; l/Vhile a" re atively' moderateelevation of pressure of solvent vapor above its vapor pressure corresponding controlled by the temperature of the cooling water isisuilitzienttoproduce an abundant condensation of solvent vapor, "raise the'pressure of'the mixture of air and:

3 stage to its temperature as I prefer to solvent vapor considerably above this value whereby to prepare the'mixture for the third of condensation. In the third stage, as

water-1'. 'driven--.--. is compressed? to an elevated pressure, say fiveltof ten atff niospheres. In the process ofcompressionthe gas and vapor becomes heated and the pipes 117 and 118.

Instead of the condenser; and the iaseaevi pressure of the mixture before and after ex- I pansion. r

The operation The cooled compressed gas and vapor is taken from said condenser and expanded.

and cooled by its expansion. The expansion apparatus preferably consists of an air vmotor 123 connected to said condenser through the pipe 124'. The cooled gas and vapor, at e through said motor and. operating it, ex-

pands and at the exit of the motor is at a.

substantiall reduced or refrigerating temstorage tank.

The expanded and refrigerated gas and v'apor are conducted from the air motor into ;a condenser .125. Said condenser maybe i'milar in constructionto said condensers lland' 116 and formed with a lurality of "pipes 126 throughiwhich the solirent vapor and gas is passed; Due to the 'duced temperature of the expand ed "vapor which temperature may be considerably Y .a largeproportion of.the vaporIwill be condensed and collect inthe bottoinof the condenser 125 from which it willffiow. throu tion-in elevated pressure,-ja'nd a partial conlower than atmospheric,

' h the pipe 128 to the drain tank'103. I Y

pasing an independent "cooling medium about the denser. 125, I. and vapor from the base ofthe condenser through the pipe 129 into thespace between said pipesand direct it upward within said pipe 102 an into the storage of said compressor 112 and condenser 116'constitute the second state of solvent recovery. The hot solvent vapor, mixedwith a rela evated pressure, in passing perature. aid motor is adapted tobe oper= 17 ated under loadby said gas and vaporh- .whereby to'enh'ance the cooling effect of the expansion; and for this urpose said motor may operate any desirab eapparatus, as an air compressor, not necessarily shown, which preferably is maintained under constant load, as by maintaining a constant pressure in' a eatly re? 7 space. Said condenser '125 may function p more or less as a gas expansion chamber in which the vapor and gas will become increasingly cooled as they pass toward the base of gas and vapor as they pass from the base and into the space between the cold gas;and vapor as they ass upward about said pipes may serve 9.

within said pipes an tly asist in cool-' ing and condensing t e pipes 126 of the condenser may be at theextreme reduced temperature. Theremainin' uncondensed vapor in the gas. I Condense solvent w ll flow from the space about said pipes pipes-126 of said conprefer todirect the-cold gas- 126-through the pipe130 a the slain pipe 102. Said condenser is preferabl encased in a heat-insulating 'acket 131 w ereb to mains in the as pass through the pipe135' into the top 0% reduce absorption of eatof the atmosp ere by the cold gas and vapor.

Said air motor and regenerative condensator 125 constitute a refrigerating appa- V ratus and its operation constitutes the third stage of solvent recovery.

The cold gas and whatever small proportion of uncondensed solvent vapor yet. re-

factory condensation of solvent vapor may be attained without the operation of the third stage of the recovery apparatus. A pipe 136 may serve to connect the discharge pipe 124 of the second stage condenser 116 to the return pipe 135, and the third stage will be by-passed upon opening the valve 137 in said pipe and closing the valve 138 in said pipe 124 adjacent the air .motor.

When the third stage is by-passed, the

valves 139 and 14.0 in the

pipes

128 and 130 will be closed to isolate the third stage from the storage tanks.

The solvent recovery apparatus is arranged to circulate a minimum volume of gas, as air, and a maximum amount of sol vent vapor, whereby to enhance the efli: ciency of solvent recovery. Furthermore, with a relatively great proportion of sol vent vapor to air in the drying chamber the F danger from explosion is reduced.

, impregnating solution and havin 5 trance slot, for the web at one' en and an 5 .exit slot for the wet impregnated web having an n and an exit slot at the other end disposed. with its entrance slot adjacent the 'exit slot e .invention may be applied to other specific I embodiments without departing from the spirit thereof.

I claim: i

1. Impregnating, drying and solvent recovery. apparatus for material in the web comprising thecombination of a closed impregnating device adapted to contain an an enat the other end, a drying chamber entrance slot at one end of the impregnatin 'device, a closed C0111". partment extended etween the impregnat-' ing device and drying chamber arranged to enclose the wet impregnated web in its passage from the exit slot of the im regnating device to the entrance slot of t e drying; chamber, said impregnating device and dry dried. I

substance which consists in impre stance when 'dry.

losicsubstance. whereby ing chamber each having self-contained power-driven means to move the web there- 'through, said drying chamber havingheating means disposed within it tof-evaporatc the solvent from the solution in the web,

and solvent recovery apparatus arranged to receive and condense solvent vapor circulate-d through itfrorn thedrying ,cham- I ber.

. 2. The method of making a fluid-permea'- ble textile material characterized by'being' impregnated with a porous solid-cellulosic substance which consists in impre the material with a solution of the ce lulosicating substance containing a volatile solvent, and drying thewet lmpregnated material at a relatively rapid rate, whereby to form arti-- ficial pores in the cellulosic substance when 3. The method of making a fluid-pennea ble textile material characterized by being impregnated with'a porous solid 'cellulosic atins the material with a solution of the co lulosic substance'containing a volatile solvent, and drying the wet impregnated material at a re atively rapidrate, whereby to form artificial pores in the cellulosic substance in the process of drying which will remain in the cellulosic substance when the impregnated material is dry and the cellulosic substance is solid. 1

4:. The method of making a fluid-permeable textile material characterized by being impregnated with a porous solid oellulosic substance which consists in .impregna the material with a solution of the co lulosic substance containing a volatile solvent, and

drying the wet impre ated material at such a tem erature t at pores will be formed arti cially in the cellulosic substance which. will be permanent in the sub- .5. The method of making a fluid-permeable textile material characterizedby being impregnated with a porous solid oellulosic substance which consists in impre ating the material with a solution of-the ce ulosic substance containing a volatile solvent, and drying the wet impre ated material at a temperature substantia y equal to or above the boiling point of the solvent in the cellu-. pores will be formed artificially. in the cellulosic substance which will be permanent in the when dry.

6. The method of making-affluid-permem I ble textile material-characterizedby being impregnated with a porous solid cellulosic substance which consists in'impre sting the material witha'. solution of the ce lulosic substance containing a volatile solvent, and drying the wet impre ated material at such a temperature an in an atmosphere saturated with solvent vapor that pores will 10 drying the wet impregnated material at a tem erature substantially equal to or above the iling point of the solvent in the cellulosic solution and in an atmosphere saturated with solvent vapor whereby be formed artificially in the cellu osic substance whichwill ,be permanent in the substance when dry.

In testimony whereof, I have signed my name to this specification.

ERNEST LIONNE.

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