US593660A - Half to william evans - Google Patents

Description

(No Model.)

H. HOLMES.

PROCESS 0F DBPILATING EIDES 0R SKINS.

No. 593,660. Patented Nov. 16, 1897.

. gases.

UNrrnD STATES muon.

ATENT HENRY HOLMES, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE- I-IALF TO WILLIAM EVANS, OF SAME PLACE.

PROCESS OF DEPILATING HIDES O R SKINS.

SPECIFICATION forming part of'Letters Patent No. 593,660, dated November 16, 1897.

' Application filed December 22,1896. Serial No. 616,578. (No specimens.)

To all whom it may concern:

Be it known that I, HENRY HOLMES, a citizen of the United Statcs,*residing at the city of Phi1adelphia,in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in the Process of Depilating Hides or Skins, of vwhich the following is a speciiication.

My invention has relation to a process whereby'hides/or skins may be depilated in from eighteen to twenty-four hours and thoroughly prepared for the subsequent operations of leshing and tanning.

Hitherto the usual mode whereby hides and skins were successfully and completely depilated and prepared for fleshing or tanning was that known as the limingi process or method, wherein the hides or skins were covered with a paint or layer of lime applied to both the iiesh and the hair sides and subjected to the caustic action of the lime for a period ranging from ten to fourteen days.

' My present invention is designed to accomplish ,the same end as the liming process above referred to and to thoroughly and completely depilate the hide or skin in a materially less time-to wit, in from eighteen to twenty-four hours.

In the carrying out of my invention I iirst subject the hide or skin to the action of a bath consisting of a strong solution of sulfid of sodium, the strength of the solution varying withv the nature ofthe hideor skin to be treated, in an open vessel which will permit of the escape of noxious and destructive Then the hide or skin and solution are agitated by means of a paddle or paddles, after which the skin or hide is permitted to remain at rest in the solution for about ten or twelve hours, when the strength of the solution is gradually diluted while the -hide or skin remains therein, the caustic strength of the solution being thereby gradually weakened until the hides or skins remain in a bath of pure or substantially pure water. The result of this process is a hide or skin which is pulpy, porous, soft, and well adapted to undergo the subsequent operations of leshing and tanning. A

The nature and scope of my invention will be more fully understood from the following description, taken in connection with the accompanying drawings, forming part hereof, in which-e Figure l is a transverse sectional view of an apparatus designed to carry the depilating process of my invention into eect, and Fig. 2 is a longitudinal sectional View of said apparatus.

Referring to the drawings, A represents a vat or tank, whichqis preferably cylindriform, having an opening extending longitudinally across the upper end. On the open upper end is mounted a shaft b, carrying a series of paddlesB and adapted to be revolved or rotated by a belt b2 and pulley B', as illustrated in Fig. 2. The shaft b is eccentrically located, so that the paddles will dip into the upper portion of a liquid placed in the vat and to one side ofthe vertical center of the vat. The rotation of the shaft b and paddles B, by reason of the position of the paddles, will'cause a circulation of the liquid, as indicated by the arrows in Fig. l.

In the vat A is placed sulfid of sodium in solution of required strength, and the hides or skins to be treated are submerged in this solution and agitated bythe revolution of the paddles B. rllhe hides travel in the liquid from the bottom of the vat along its sides to the top of the vat,when they are pushed down by the paddles and along the sides of the vat to the bottom thereof. By this action of the paddles the hides or skins are thoroughly washed in the solution. At the side of the vat A is arranged a pipe cl, controlled by a cock or valve d', and adapted to discharge into the vat at or near its upper end a stream of fresh water, and at the side ends of the vat are arranged a series of valve-controlled outlets c, adapted to permit of the discharge of the solution in the vat. When the valve d is open and the outlets c are also open, a curv rent of water enters the vat and mixes with the solution of sodium sulfid therein and gradually dilutes it, the diluted mixture flowing through the outlets c, thereby permitting of a still further dilution of the solution upon the entrance of more fresh water from th pipe d.

The operation of the apparatus is as follows: The solution of sodium suliid and the ICO hides or skins are introduced into the vat and subjected to agitation by the paddles for a period of about half an hour. The hides or skins are then permitted to remain at rest in the solution over night or for a period ranging from ten to twelve hours, when the hides or skins and the solution are preferably again agitated by the paddles for a period of about two hours. During this second agitation the valve d is opened to permit of the constant fiow of water through pipe d, and hence the addition of fresh water to the solution of sodium sulfid for the purpose of gradually diluting said solution, and at the same time the outlets c, of approximately the same area as the area of pipe d, are also opened to permit of the escape of the solution. During the entire operation, the upper end of the vat being open, all noxious and destructive gases are permitted to escape from the vat. The constant infiow of water and constant outfiow of solution are so proportioned to the bulk of solution in the vat that it requires approximately two hours to replace the solution in the vat with fresh water. Thus if the vat contains, say, four hundred and eighty gallons the infiow and outiiow should be approximately four gallons per minute.

From the description of the operation above set forth it will be understood that my depilating` process consists in certain well-defined steps, which may be summarized as follows: first, the placing of the hide or skin in abath of sulfid of sodium of a required strength of solution; second, the agitation of the hide or skin and the bath for a comparatively short period of time; third, the subjection of the hide or skin to the action of the solution for from ten to twelve hours without agitation; fourth, the second agit-ation of the hide or skin and the solution, and, fifth, the gradual weakening of the strength of the solution by dilution during the second agitation until the bath in which the hide or skin is immersed becomes free or substantially free of caustic matter. Of allthese steps the fifth appears to be the most important, for by it the hide or skin is subjected to a washing by a solution of gradually-decreasing strength, which solution washes out whatever caustic matter remains in the substance of the hide or skin and washes out or removes the dissolved hair and certain iibrous matters and breaks up the gristle of the hide or skin, thus leaving the same pulpy, porous, soft, and well adapted to undergo the tanning and other subsequent operations.

As far as l am enabled at present to understand, the chemical action of my process upon the skin is as follows: The solution of sulfid of sodium of normal strength burns out and dissolves the nitrogenous and hairy matters and swells the skin, rendering it pulpy and porous, but fills the pores with caustic matter in a more or less undissolved state and in chemical combination with the substance of the skin. lf this caustic material were permitted to remain in the skin, it would speedily eat up those matters which give to the finished leather its life or vitality and would render the skin brittle, liable to split or break, and imperfectly susceptible to the tanning operation. By agitating the skin a second time in the solution, which is gradually weakened by dilution, I am enabled to wash out this caustic matter, and at the same time the diluted solution appears to penetrate the body or substance of the skin and acts upon the gristly matter, which it breaks up and renders porous. The caustic matter, l believe, is dissolved by the weakened solution and is thus carried off as the solution escapes from the vat. The original solution should be of a strength varying from 2 to (5o Eaum test, according to the nature of the hide or skin to be treated, as well as the uses to which the skin or its hair is to be put.

Having thus described the nature and objects of my invention, what l claim as new, and desire to secure by Letters Patent, is-

l. The herein-described process of depilat ing hides or skins, which consists in subjecting the hides or skins to a bath, consisting of a solution of sulfid of sodium of required strength, then agitating the hides or skins and the solution for a relatively short interval of time, then subjecting the hides or skins to the action of the solution for a comparatively long period of time and without agitation, then reagitating the hides or skins and the solution and finally gradually weakening the strength of the solution by dilution during this reagitation, substantially as and for the purposes described.

2. The herein-described process of depilating hides or skins, which consists in subjecting the hides or skins to a bath consisting of a solution of sulfid of sodium of required strength, then agitating the hides or skins and the solution, then aga-in subjecting the hides or skins to the action of the solution but without agitation, then reagitating the hides or skins and the solution and at the same time gradually weakening the strength of said solution and finally permitting during the entire operation the free escape of gases generated in ihe solution, substantially as and for the purposes described.

In testimony whereof I have hereunto set my signature in the presence of two subscribing witnesses.

HENRY HOLMES.

lVitnesses:

J. WALTER DoUoLAss, THOMAS M. SMITH.

lOO

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