Process of Unhairing Hides or Skins of Animals and the like.
Year: 1898

page_text: Date of Application, 27th June, 1898-Accepted, 24th June, 1899
COMPLETE SPECIFICATION.
Process of Unhairing Hides or Skins of Animals and the like.
I, GEORGE DEXTER BURTON, of 138, Lincoln Street, Boston, in the County of
Suffolk and State of Massachusetts, Electrician, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
The invention consists in subjecting the skins or hides to be unhaired to the
action of a suitable solution and a current of electricity, which is passed through
the solution in which the hides or skins are placed, as hereinafter described.
In the accompanying drawings Figure 1 is a side view of the tank containing
the solution, showing one side of the tank removed. The same figure also shows
the generator for furnishing current to the tank, and also the controlling switch.
Figure 2 is a top plan view of the same.
Figure 3 represents a section of the tank on the line of Figure 2.
Referring again to Figure 1, A is the tank containing the solution. B is the
solution, and C C screens, to prevent the skins or hides from coming in contact
with the electrodes 1) 1). E is a screen at the bottom of the tank, to prevent
the skins coming in direct contact with the lime and arsenic, should the
liquid remain too long unstirred. F is the switch, for controlling_the
electric current. G is the dynamo. H H are conductors to the electrodes D D.
JJ are the conductors leading from the dynamo to the switch.
My process and apparatus for the unhairing of all kinds of animal skins consists
of a tank composed of wood, or other non-conducting substance, into which is
placed a suitable solution, and at each end of the tank two carbon plates, one-half
inch thick and twelve by sixteen inches, properly connected to a suitable source
of electricity, preferably that consisting of a current of electricity varying
from 1 to 20 volts and from 30 to 75 amperes, according to the size of the tank
and the gravity of the solution and the number of skins to be unhaired. In a
solution consisting of 70 gallons of water I add 10 pounds of quicklime (unslacked)
and 1 pound of red arsenic, making the solution, after the lime is thoroughly
dissolved and mixed with the arsenic, of a specific gravity of 1025 at 60° Fahrenheit,
which is accomplished by stirring the bath briskly for a few minutes. I then
place in such bath four dozen skins to be unhaired, which have previously been
broken or softened by soaking in water or a proper solution, such as kangaroo
skins, calf skins, or one dozen ox hides, etc. I allow the skins to remain in the
bath from one hour and ten to one hour and thirty minutes. When the skins are
removed from the bath or solution the hair is easily removed from the skin. The
old process for removing the hair requires the skins to remain in solution from
fourteen to twenty-one days and leaves the skins, after they are unhaired, in a
condition whereby they have to be soaked in a prepared solution for some time,
in order to bring them to a proper state to be treated by the tanning process:
while, by my process, the hides or skins are ready, as soon as unhaired, to proceed
at once with the tanning process, after being subjected to a thorough washing in
cold water. I do not use a warm solution as is now used in the tannery, which is
detrimental to the finish of the hides and skins.

page_text: The essential features of my process of unhairing hides or skins consists of
making a solution in the proportion of 70 gallons of water, 10 pounds of quicklime
and 1 pound of red arsenic, and passing a suitable electric current through the bath
containing the hides or skins. The proportions, of course, may be varied, in
accordance with the size of the tank, the number of skins to be treated at one time
and the quantity of the liquid used.
The screen in the bottom of the tank is about 21%, inches therefrom; it is made of
a non-conducting substance and has a perforated bottom, best shown in Figure 3,
which prevents the skins or hides from coming into direct contact with the lime
or arsenic, should it settle and the bath or the liquid remain too long unstirred.
I also use as a modification a solution of 70 gallons of water, 10 pounds of
quicklime, 1 pound of red arsenic and 1 pound of alum, which simply adds another
element to the solution and for some skins is preferable, as it causes the hair cells
or pores to immediately contract as soon as the hair has been removed from the
skin.
The electric current employed in the process hereinbefore described is of such a
strength as will raise the hair and permit circulation through it.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is―
1. The process of unhairing animal hides or skins which consists in subjecting
the hides or skins to the action of an unhairing solution, and a current of electricity
passed through said solution, said current being of sufficient volume to raise the
hair and permit circulation through it.
2. The process of unhairing animal hides or skins which consists
in subjecting said hides or skins to the action of a solution of quick-
lime, and red sulphide of arsenic, and an electric current passed through said
solution, said current being of sufficient volume to raise the hair and permit
circulation through it.
3. The process of unhairing hides or skins, which consists in subjecting said
hides or skins to the action of a solution composed of quicklime, red sulphide of
arsenic, and water in the proportions of about ten pounds of quicklime, one pound
of red sulphide of arsenic, and seventy gallons of water, and an electric current
passed through said solution containing the hides or skins, said current being of
sufficient volume to raise the hair and permit circulation through it.
4. The process of unhairing animal hides and skins, which consists in subjecting
said hides or skins to the action of an unhairing solution, and a suitable electric
current passed through said solution, and avoiding injury to the said hides or
skins by preventing their coming in direct contact with sediment should the
solution remain too long unstirred, said current being of sufficient volume to
raise the hair and permit circulation through it.
5. The process of unhairing animal hides or skins which consists in subjecting
the hides to the action of an unhairing solution, and a current of electricity passed
through said solution in lines parallel with the layers of skins, said current being of
sufficient volume to raise the hair and permit circulation through it.
In testimony that I claim the invention above set forth I affix my signature
in presence of two witnesses at Boston, Mass., U.S.A.. May 14. 1898.
Witnesses :
E. F. PHILIPSON.
GEO. STELNER.
GEORGE DEXTER BURTON.