An Improved Method of Treating Hides and Skins for the Purpose of Removing Lime and other Undesirable Matter therefrom, and Preparing the Hides and Skins for being Immersed in or other- wise Treated by Tannin.
Year: 1896

page_text: Date of Application, 13th Mar., 1896-Accepted, 29th Aug., 1896
COMPLETE SPECIFICATION.
An Improved Method of Treating Hides and Skins for the Purpose
of Removing Lime and other Undesirable Matter therefrom, and
Preparing the Hides and Skins for being Immersed in or other-
wise Treated by Tannin.
I, JAMES ANDERSON MCINTOSH Oil Merchant, Love Lane, Quayside, Newcastle-
on-Tyne (a communication from abroad) 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 of a novel method of treating hides and skins for the
purpose of removing lime and other undesirable matter therefrom and preparing the
hides and skins for being immersed in or otherwise treated by tannin, by the adoption
of which some of the preliminary stages in the manufacture of leather are dispensed
with, and the time ordinarily occupied in tanning is reduced by one half, and a
saving of a considerable amount of labour is effected. The hides and skins are
taken from the lime pit in the usual manner, and treated according to our method
in order to remove the lime and other undesirable matter therefrom and to prepare
the hides and skins for being immersed in or otherwise treated by tannin. The
invention possesses advantages over every known process of treating hides and
skins with the same or similar objects, inasmuch as I have discovered and prac-
tically applied an effective method for the purpose. I use aerated water prepared
by impregnating water with carbonic acid gas, and inject the aerated water into an
bermetically sealed receptacle, wherein the hides and skins are hung, which has the
effect of completely removing or destroying the lime and other undesirable matter,
and rendering the hides and skius pliable and opening the pores, thus enabling
them to be placed in tannin of a strong degree which they quickly absorb and in a
much shorter space of time than would otherwise be required, are completely
tanned ready to be curried. In working my invention any apparatus or plant which
may be found effective may be used, but the apparatus or plant which is hereinafter
described has been found effective for all practical purposes.
The apparatus or plant consists of a generator wherein carbonic acid gas is
generated or produced by means of bi-carbonate of soda and sulphuric acid, or in
any other feasible manner, and taken from the generator to a gas holder and thence
to a force pump which forces the gas, together with water, along a pipe leading to
the hermetically sealed receptacle, wherein the hides and skins are hung, the said
pipe is fitted with a steam jacket to heat (when necessary) the water so impregnated
with the gas, prior to its being discharged into the receptacle. The receptacle is
made to stand pressure and is fitted with corresponding flanges on each side so that
sticks may be inserted to admit of the hides or skins being hung thereon. The
receptacle may be made with a surrounding or encircling jacket, and steam let into
the jacket instead of using the steam jacket or the pipe leading to the receptacle
as before described, the receptacle is constructed with an opening preferably at one
end, having fastenings to render it airtight. In all cases where the interior of the
receptacle is constructed wholly or partially of material which is subject to
chemical action injurious either to the receptacle or to the hides or skins it should
be lined with copper, lead, or other suitable material. It is also désirable for the
receptacle to be placed upon a cradle in such manner that when it is fully charged
it may be moved with a rocking motion, thus causing the gas to more thoroughly
permeate the hides and skins.

page_text: In order that the apparatus and plant before mentioned may be more clearly
understood reference may now be made to the accompanying drawings, wherein
Figure I is a plan view of the plant, including a generator A., gasholder H.,
force-pumps J. and J 1, and a receptacle T.
Figure II is a perspective view of the receptacle T.
A. a generator in which carbonic acid gas may be generated.
B. is a feeding box which supplies sulphuric acid to the generator A.
C. an opening to admit of bi-carbonate of soda being placed in generator A.
D. paddle arms attached to a driving wheel E. and worked by belting F. to mix
ingredients.
E. a driving wheel to be worked by belting F.
F. belting worked from a shaft and attached to driving wheel E.
G. pipe supplying carbonic acid gas to gasholder H.
H. a gasholder.
I. and 11. pipes leading from gasholder H. to a double force pump J. and J 1.
J. and Ji. a double action force pump worked by a central shaft K. and
belting L. the pump J. takes gas from pipe I. and water from pipe M. and the
pump J 1. takes gas from pipe 1 1. & water from pipe M 1.
K. central pump shaft worked by belting L.
L. belting working shaft K.
M. and M 1. water pipes from a tank N. and supplying pumps J. and J 1.
N. water tank fitted with a ball cock O. receiving water from pipe P. and
supplying pipes M. and M 1.
O. a ball cock in tank N. regulating the inflow from water pipe P.
P. water supply pipe to tank N.
Q. and Q 1. pipes discharging aerated water from pumps J. and J 1. to a main
pipe R.
R. a main pipe receiving aerated water from pipes Q. and Q 1. and surrounded
by a steam jacket S. emptying through a tap R 1. into receptacle T.
R 1. a tap at the extremity of pipe R. to shut off the supply of aerated water.
S. a jacket surrounding the pipe R. having a steam supply pipe S 1. and a corre-
sponding discharge pipe S 2.
S 1. steam supply pipe to jacket S.
S2. discharge pipe froin jacket S.
T. a receptacle which can be hermetically sealed, having inside flanges or
supports T 1. and fitted with a pressure gauge U. a waste gas pipe V. outlet
pipe 1. water gauge V 2. the receptacle opens at one end by means of a screw
bolted lid W. and is fed with aerated water from pipe R.
T 1. flanges on both sides of the receptacle acting as supports for horizontally
placed sticks X.
U. a gauge to indicate the pressure in the receptacle.
V. a waste gas pipe to conduct the superfluous gas back to gas holder H.
V 1. an outlet pipe to empty the receptacle T.
V 2. a water gauge to indicate the height of the aerated water in receptacle T.
W. a lid or cover entirely covering the end of the receptacle T. and held in
position by means of screw bolts.
✗. sticks or bars resting on flanges T 1. holding the hides or skins Y.
Y. hides or skins hanging from sticks X.
The
takes
Carbonic acid gas may be obtained in any feasible manner, but in order to
generate it from bicarbonate of soda and sulphuric acid, we take in the proportions
following, namely, to six pounds of bicarbonate of soda one piut of sulphuric acid,
a sufficient quantity to charge the generator. The gas passes from the generator
to the gas holder and is taken from the gas holder by the
pump.
the water and gas simultaneously and forces them through two pipes converging
into the supply pipe and through the latter into the receptacle. During the
progress of the gas and water through the pipes leading from the pump to the
receptacle the water becomes impregnated with the gas and discharges into
pump

page_text: the receptacle in the condition of aerated water. The supply pipe is fitted with a
steam jacket in order that the impregnated water may be heated, which it may be
found desirable to do when the hides being treated are required for kip or similar
leather, but which will be found undesirable when the hides are intended for crop
leather. The supply of aerated water is continued until such time as the hides or
skins banging in the receptacle are covered, and it has in addition been found
desirable to regulate the proportionate amount of gas and water forced into the
receptacle so as to attain and maintain a pressure in the receptacle up to about
thirty pounds to the square inch. The hides or skins are hung from sticks which
are supported on each side of the receptacle at a sufficient distance (say of one
inch) apart to enable the aerated water to circulate between and reach every part
of the hides or skins and after the hides or skins have been subjected to the action
of the aerated water for about one hour they may be removed and are ready for
tanning. It may be found desirable to have the receptacle resting on a cradle in
such manner that when the receptacle is fully charged it may be rocked or moved
so as to cause the gas in the aerated water to more thoroughly reach all portions
of the hides or skins. Hides intended for crop should be treated with cold aerated
water as they require to be harsh and firm, and those intended for kip or similar
leathers should be treated with hot aerated water.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same may be performed, I declare that what
I claim is :-
An improved method of treating hides and skins for the purpose of removing
lime and other undesirable matter therefrom and preparing the hides and skins for
being immersed in or otherwise treated by tannin which consists in treating the
hides and skins placed in an hermetically sealed receptacle with aerated water
(prepared by impregnating water with carbonic acid gas) as herein before described
and explained.
Doted this 7th day of March 1896.
JAMES ANDERSON MCINTOSH,
Newcastle-on-Tyne.