US1556598A - Leather-degreasing process - Google Patents

Description

A. J. HANGLIN LEATHER DEGREAS ING PROCESS Oct. 13

Original Filed Dec. 6, 1919 Patented oai. 13, 1925-.

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Application led December 6', 1919,-Seria1 .ll'o-.IMSQ Blj` Renewed Iarchjfim. A

ToaZZ whom/jt may concern; I I Be it known'thatl I, ALBERT J. HANGLIN,

acitizen of the United States,- residing at Newark, New Jersey, have invented certain new andfuseful Improvements-in Leatherof materials such-as theskins and ide's o t greasing o vil .ing is a clear, full,fand exact description.

Degreasing Processes, of. which the' follow- This invention relates to the de easin animals and sh, andV particularly to Hic deraw, wet condition before being subjected tothe limingvor tanning processes, and the invention has for its general object -an improved process for effecting the degreasing ofthe aforementioned. and other materialsand for conserving and recovering the.sol-- vent employed and the grease removed.

' apparatus being shown on the accompanyprocess of this invention;

' that is, as they are Heretofore it has been customary to e'ect the degreasing of skins to'be tanned'after the liming operation, andso far as I am aware, no' successful process' or means has ever before been devised for degreasing skins or hides in their raw wet conditiontaken romthefanimal or fish, and also skins which have been salted, pickled, or otherwise treated b the packer, butcher, or other person who olds them in s uch a condition that putrefaction will not take place' before the skins `are treated by the tanner. Thelprocess is also applicable to dry hides or skins which have not been treated by the tanner? In carryin out thel novel process, I preerably eploy apparatus suc as that herein illustra and which. constitutes a part of the present invention, this degreasing in` sheet of drawings in which ig. A1 is a side elevation of the essential parts of the apparatus for carrying out Lthe Fig. 2 is a longitudinal drum having a perfora false bottom 12 Y between which. and the outer wall. of the drum a steam pipe Mis-located, this pipe being'connectedthrough the hollow trunnion 4 by a connection 16 (allow' the'ppe 14 to revolve with the ilrum), lh a pipe 18 f' such materials when in their'-v pulley 32 connected ing to a storage tank t0 pass from lan Sgply -connected to t e pipe 68 and controll by section through the rotatable drum, in which the main Stepfrom the condenser valve 82 in said pipe from any .suitable source ofsteamsupply l' f'- age for the so vent and its contained grease and water, an air intake Apet cock 26 and Ywith a drainage cock 28 for the steam and the dium is "al'so rovided with a drainpipe ,14.- Within the drui'irare paddlesor l aillepplates 30 which serve to insure ofthe material to ,be degreased with the solvent when the drum rotates. 'A driving of power may serveto elect the rotation of the drum.

' Through the. other hollow trunnion 6 ofv ther drum, the interior of the' drum is rotatably connected by a union 34. with apipe 36, which inturn isV connected by a double 'll-joint 38 .with a ipe 4'0` leading to a condenser coil 42; .wit a second pi 46, and with a third pipe 4811eadin to a still 50, the condenser coil 42 Abeing so connected through apipe 51'- with the storage tank `46. By means of .cocks 52, 54 and 5 6, -thevarious operative The storage tank 46 is connected by a pipe 58 to a vacuum pump 60,l which discharges through a 4pipe'62 into a discharge throughsaidpump 60. The storage 46 is. surround through which cold water may be caused suitable source of to any suitable source A tank 64 h containing any suitable material or chemical 'for recovering vapors Vwhich may N pass 44 leadconnections between the 36'and the other pipes hereinafter to described maylbe effected.'

ed by a water jacket-66 the cock 70, this water preferably then passingv through 4a'pipe`72 into the condenserA tank 74 enclosing the condenser coil 42, and

76 to the discharge.

tank through an` outlet' pliebe still 50 is surrounded by a steam jacket 78 connected by a pipe180 to n suit- 4 able source of steam supply controll by'a erably provided with severalfpet cocks 84, 86 and 88 to permit the entrance of air, and

,andthisstll'ispref-v ics with a valve 94.

Ainto the still 50, this pipe' being provided The storage tank 46 is preferably provided with a vacuum gage 9 6 and a vacuum relief pet cock 98, and the connection 5l between the condenser and the-storage tank is preferably provided with a sight glass 100.

In carrying out the novel process `of this invention with the novel apparatus just described, the hides or skins to be degreased are introduced into the drum 2, through the opening 23, normally closed by the door 22, together with the solvent, a, suitable proportion, when naphtha is used as a solvent, being about 35. gallons of naphtha for each 100 pounds of wet hides or skins. In order to produce the internalv pressure in the drum, which is one of the lmportant novel i features of the process of this invention, the

naphtha is preferably introduced into-the drum at a temperature below normal room temperature, say about 60 F., andthe drum is then closed and sealed air-tight and is set in rotation. Heat is then applied through the steam pipe 14 until the' temperature of the contents of the drum has been raised to approximately 80 F., thereby attaining an internal pressure of about 3 pounds, due to the expansion of the air and the naphtha.

The agitation of the contents of the drum, while subjected to this internal pressure, by the continued rotationv of -the drum, causes the naphtha to penetrate the hides or skins and partly to dissolve and partly to emulsify the grease and to displace so-m'e of the water in the hides or skins.

The drum is rotated for a suitable length of time, the length of time naturally varying with the size of the drum and with the amount and thickness 'of 'the material treated. I have found the time required to vary from 15'minutes to an hour, in ac-4 cordance with-the varying conditions just enumerated.

After the drumhas been rotateda suitable len h of time, it is stopped, the drain cock 24 1s vconnected with the pipe 92, and the liquid is dra-wn olf into the still 50, all valves in the drum being preferably opened to allow free ingress of air to facilitate the draining of the liquid.l lVhen the draining is completed, the drum is disconnected from the still, the drain cock 24 closed, the same quantity of fresh cold naphtha. as used in the lirst instance is introduced into the drum, and .the operation repeated. The liquid is then again drawn off into the still through the drain cock' 24 and pipe 92, and all valves again closed and, the vacuum pump vbeing in operation,. the drum is revolved and the valve 52 on' the pipe 36 leading to the vacuum pump through the pipe 40, condenser coil 42, pipe 51, storage n tank. 46 and-pipe 58 is opened, the valves 456 and 54y being closed, and this connectionv 2 in avolune so small that it Will not overcome more than two or three inches of vacuum, the pump 60 being maintained in operation. The pump 60 is then continued in operation until allnaphtha vapors are removed from the drum 2; this operation usually taking from 15 minutes to an hour, and the result may be observed in the sight glass 100. This completes the degreasing operation and the drum is opened and the contents are removed.

-To recover the solvent from the still 50, the liquid `'and semi-solid material which has beenI drained from the drum 2 into the still are heated until most of the volatile solvent is driven'off through the pipes 48, 40' and condenser-pipe 42 mto the storage tank 46, the still 5() being heated by the steam jacket 78. In order to recover still more of the solvent, the still is connected with the vacuum pump through the storage tank and condenser, the valves in the still' are closed, and the pump vis operated until a maximum vacuum is attained in the still. The pet cocks 84,86 and .88 on the bottom of the still are" then opened and air is admitted in volume suicient to maintain within four or live inches of maximum vacuum While the pump is continued in operation, this operatlon being continued until all the solventis removed. The still is preferably provided with a cup connection 102 to facilitatewashing out of the still, this connection being normally closed by valve 104. The grease in the still may be drawn off through the drainage cock 90. Any vapors which pass through the vacuum pum 60 may be recovered in the discharge ta 64 by providing suitable chemicalsor other means for effecting combi-nation or condensation.

From the foregoing description of the novel degreasing process and the apparatus for practicing this process, some ofthe advantages ofthe process will be apparent. By treating raw. Wet hides and skins under pressure accompanied by agitation, I secure a vpractically complete removal of grease, something that has not heretofore been done with wet material, such as pigskins, sheepskins, goatskins, dogskins, seal and porpoise skins, and the other raw skins used in thel -tanning industry.

The advantage of removing the grease before the tanning operation is begun will be obvious to those lskilled-in the art, such removal Serving to effect a shortening of the time required for liming in the beamhouse e'ect of caustic lime and sodium sulphide because of the fact that the materials used can more rapidly attack the hair cells of the degreased hide and thus permit the removal of the hair or wool is important since it lessens'the harmful on the raw hides or skins, resulting -therefore in the production of a iner and stronger leather in a shorter time than lby processes heretofore practiced. The process also is more economical of solvent than processes heretofore used, and `a greater-percentage of grease is recovered in a usefulY form. Upto the present` time' most sheepskins and many other kinds offskins have been onlypartially degreased before tanning. Vha't grease has been left in the skins, if it interferes' with the roper finishing of the leather, is removed a ter the tanning process, being usually removed from the dry tanned leather. This pract'ce results also in the re'- inoval of the grease and oils which the tanner has used in his processes. Moreover, as. naphtha does not dissolve alkalis, these .if used in conjunctionl with oils or soap in' the stuiiing or fat liquoring treatment ofthe `weaken 1t.

the leather and subseleather are left in the leather fibre and quently 0 act upon' When my process is employed, the de'- greasing of the tanned leather is'not necessary, and therefore the greases and oils used in stuing are rnot removed, the quality of the resultant leather is therefore better, and the danger of injury to the leather bythe excessive heat sometimes employed with processes now in use is avoid It will be understood that the process may.

be practiced with any suitable grease sol- "vent, vsuch as na lcarbon bi'sulphl e,

in a shorter time. Thisy be understood that f That Vimprovement in fish,

- -Signed at Newark, New Jersey,

htha, carbon tetra-chloride, tetra-chlorfethylene, these solvents being capable of dissolving animal and fish oils and grease and yemulsifying them under the conditions produced with the apparatus herein described. To facilitate continuous operation, it will a battery of degreasing drims may be associatedwith a single pump, still, condenser and storage tank, such an obvious modification of the structure hereinshown not requiring special illustration.

1 Although the invention is particularly described in connection with the degreasing of itis obvious that the process maybe utilized in'degrea'sing other materials, such, for eX- ar'nple, as wool.

^ What I claim as new is:

he art of degreasing raw wet skins or hides of animals and which consists in enclosing the material .to'be degreased and areadily volatiliz'- able grease solvent in a-drum, sealing-the j drumair tight, raising the temperature of. the drum contentsto a degree to meure the production of substantial pressure in the drum, the vinitial temperature of the drum contents being such that the temperature required to produce such pressure will not be so high as to injure the skins or hides, then agitating the drum contents, while lmaintaining the internalpressure, to effect a solution or emulsion ofthe'greasa-and then removing the solvent with its contained grease and water.

this 2nd day of December, 1919. f

^ ALBERT J. HANGLIN.

raw wet skins I,or hides of animals and fish, v

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