IMPROVEMENTS IN TANNING 4 HIDES, AND IN APPARATUS TO BE USED FOR THIS PURPOSE
Year: 1873

page_text: LETTERS PATENT to John Evershed, of Shere, in the County of
Surrey, Tanner, for the Invention of "IMPROVEMENTS IN TANNING
4
HIDES, AND IN APPARATUS TO BE USED FOR THIS PURPOSE.”
Sealed the 26th August 1873, and dated the 24th June 1873.
´PROVISIONAL SPECIFICATION left by the said John Evershed at the
Office of the Commissioners of Patents, with his Petition, on the
24th June 1873.
I, JOHN EVERSHED, of Shere, in the County of Surrey, Tanner, do
5 hereby declare the nature of the said Invention for "IMPROVEMENTS IN
TANNING HIDES, AND IN APPARATUS TO BE USED FOR THIS PURPOSE," to be as
follows:-
The principle of "tanning by percolation," has been long known, and
various Patents have been granted in the United Kingdom for apparatus.
:intended to render available the great advantages this system of tanning
has appeared to present over that in common use in the great saving:
effected in time and tanning material, ..

page_text: Some of the methods Patented for the utilization of this idea have
been fully tested on a manufacturing scale and for a considerable time,
but have always resulted in failure; this want of success I believe to
have arisen mainly from two causes :—
1st. The cumbrous and expensive character of the apparatus used,
cach hide or skin having been treated singly (or at most in pairs) instead
of in "packs" of 80 or 100, as in the ordinary process of tanning. This
single treatment involves an enormous outlay for plant and machinery.
2nd. The absence from all previous Patents of any provision for
applying motion to the hides or skins while in process. In all good
tanning practice the necessity of constant "handling ". is fully recognised,
especially in the early stages of the process of tanning.
33
By my Invention I am enabled to treat the hides or skins in "packs
of 60 to 100 or more, instead of singly, and to apply constant or inter-
mittent motion as may be required while in process at a small cost as
compared to the manual labour of “handling," while the full advantages
of the "percolating" system are secured in a simple and convenient way,
either pressure or suction being applied as the operator may see fit by.
closing one valve and opening another.
*
The apparatus which I employ consists of a central shaft, around
which the hides or skins are to be arranged radially; each hide or skin is
first doubled over and sewn together round the edges, so as to form a
bag, which is to be attached to the shaft in any convenient way and in
such position that the thin (or "offal") part of the hide is next the
shaft, and the thick (or "butt") part outwards. Thus the thick part of
the hide occupies the outer and larger circle, while the thin part finds
room near the shaft. Arranged in this way, "100 ordinary "heavy ox
hides will occupy a space of about 3 feet 6 inches diameter at the central
shaft, and 10 feet 6 inches diameter outside, the length being from 6 feet
to 7 feet 6 inches.
"
For convenience of fixing and support to the hides I prefer to attach
strong discs to the ends of the shaft, and to enable the waste liquor to
pass away more freely I insert between the hides thin lattices of wood
covered with canvas or unbleached calico, or any suitable material of
open texture, each hide or skin being sewn up and placed in the apparatus
as described is connected by a suitable nozzle and flexible pipe with a
main supply pipe, which passes round the shaft, and is furnished with a

page_text: proper number of suitable taps or openings so as to supply each hide
with liquor when required... The main supply pipe passes through the
central spindle of the shaft, and is continued to an elevated tank, being
connected at the spindle in a way well-known so as to allow the shaft
freely to revolve on its proper bearings while the liquor is passing from
the tank to the hides. The height of the tank and the consequent
pressure will be arranged as required by the particular goods in process.
I prefer a height of about 15 feet between the central spindle and the
top of the tank, and that the pressure be regulated by a throttle valve;
but a less height will suffice.
When these arrangements are completed, tanning liquor of any kind
or strength is allowed to flow through the central pipe from the tank and
to pass into each bag of hide as described, and the shaft with hides
attached' is made to turn slowly either by hand or mechanical power, a
speed of one revolution per minute will ordinarily be fully sufficient,
and while the whole is slowly turning the feed from the tank is to be
sometimes shut off to allow the hides partially to collapse or even become
quite empty, which will allow of such a slight amount of swaying and
movement of the parts as will be found beneficial as in "handling" in
the old process of tanning. I may also use an exhaust pump in con-
nection with the feed pipe of the apparatus, so that by shutting off the
feed from the tank and turning on the pump suction in place thereof,
the pressure may be readily reversed, and either liquor or air be made to
pass through the pores of the hides in the opposite direction, accordingly
as the hides may be immersed in liquor or air at the time. As to the
quality and strength of the tan liquor used it will be regulated by the
skill of the tanner as in ordinary tan yard practice. The apparatus is
preferably mounted on supports in such a way that the lower part may
dip into a pit of convenient depth, and provided with a proper pipe or
gutter for the conveyance of the waste liquor. I consider this the best
arrangement of the apparatus for ordinary use, but it may be desirable
in some cases to let the whole be either completely removed from the
liquor in the pit underneath or nearly or quite immersed in the same
while applying the suction pump or otherwise.
Although I consider the horizontal arrangement of shaft and hides to
be the best, it may in some cases be of advantage to arrange it vertically.
or in some other position, and in such a manner as that it may revolve
either in or out of liquor.

page_text: By the arrangement of the hides in a circle as above described the
pressure on each hide is balanced by those adjoining, and the strength of
framework required is simply that sufficient to support the weight of
hides and liquor, say for 100 "heavy ox" of average size, and full of
tan liquor, a weight of 31,500 pounds, or about fourteen tons exclusivo
"of apparatus.
For sewing up the hides I propose to use sewing machines, and I also
propose to sew up latticework within the bag of hide to prevent a
'water-tight adhesion of the sides of the bags during the time that tan
liquor is being drawn into them.
$
:
•
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Evershed in the Great Seal Patent Office on
the 24th December 1873.
:
1 TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
EVERSHED, of Shere, in the County of Surrey, Tanner, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of June, in the year t
of our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors, give
and. grant unto me, the said John, Evershed, Her special license that
I, the said John Evershed, my executors, administrators, and assigns
or such others as I, the said John Evershed, my executors, admini-
strators, and assigns,, should at any time agree with and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN TANNING
HIDES, AND IN APPARATUS TO BE USED FOR THIS PURPOSE," upon the condition
(amongst others) that I, the said John Evershed, my executors or
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said. Invention, and in what manner the same was to be.
performed, and cause the same to be filed in the Great Seal Patent Office
'within six calendar months next and immediately after the date of the
said Letters Patent.

page_text: NOW KNOW YE, that I, the said John Evershed, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained.in and by the
following statement thereof, that is to say
The principle of "tanning by percolation," that is, applying a pressure
of tan liquor on one side only of the hide or skin to cause the liquor to
percolate through it, has been long known, and various Patents have
been granted in the United Kingdom for apparatus intended to render
available the great advantages this system of tanning has appeared to
present over that in common use in the great saving effected in time
and tanning material.
Some of the methods Patented for the utilization of this idea have:
been fully tested on a manufacturing scale and for a considerable time,:
but have always resulted in failure. This want of success I believe to:
have arisen mainly from two causes.
1st. The cumbrous and expensive character of the apparatus used,'
cach hide or skin having been treated singly (or at most in pairs) instead
of in "packs" of 80 or 100, as in the ordinary process of tanning.
This single treatment involves an enormous outlay for plant and
machinery, while the cost of labour per lb. of leather produced is
actually more than by the common system of tanning.
2nd. The absence from all previous Patents of any provision .for
applying motion to the hides or skins while in process. In all good
tanning practice the necessity of frequent "handling" is fully recog-
nized, especially in the early stages of the process of tanning.
By my Invention I am enabled to treat the hides or skins in "packs"
of 60 to 100, or more, instead of singly, and to apply constant or inter-
mittent motion, as may be required, while in process at a small cost as
compared with the manual labour of "handling," while the full advan-
tages of the " 'percolating system are secured in a simple and
convenient way, the bags of hide or skin being either filled or emptied
with liquor as the operator may see fit by simply closing one valve and-
opening another.
"
The apparatus which I.employ consists of a central shaft, around
which the hides or skins are to be arranged radially... The hides or skins
after having been prepared for tanning in the ordinary manner, or in
any

page_text: way that may be preferred, are each doubled over and sewn together
round the edges so as to form a bag, which is to be attached to the shaft
in any convenient way and in such position that the thin (or "offal")
part of the hide is next the shaft, and the thick (or "butt") part out-
wards. Thus the thick part of the bide occupies the outer and larger
circle, while the thin part finds room near the shaft. Arranged in this.
way 100 ordinary "heavy ox" hides will occupy a space of about 3 feet
6 inches diameter at the central shaft and 10 feet 6 inches diameter
outside, the length being from 6 feet to 7 feet 6 inches, the "cheeks"
being cut off.
For convenience of fixing and support to the hides I prefer also to
attach strong discs to the ends of the shaft. Each hide or skin being
sewn up and placed in the apparatus is connected by a suitable nozzle
and flexible pipe with a main supply pipe or pipes which pass round
the shaft, and are furnished with a proper number of suitable taps or
openings so as to supply each hide with liquor when required. The
main supply pipe or pipes pass through the central spindle of the shaft
and are continued to an elevated tank, being connected at the spindle in
a way well known so as to allow the shaft freely to revolve on its own
proper bearings while the liquor is passing from the tank to the hides.
The height of the tank and the consequent pressure will be arranged as
required by the particular goods in process. I prefer a height of about
15 feet between the central spindle and the top of the tank, and that
the pressure be regulated by a throttle valve, but a less height will
suffice.
By the arrangement of the hides in a circle, as above described, the
pressure on cach hide is balanced by those adjoining, and the strength
of framework required is simply that, sufficient to support the weight of
hides and liquor, say for 100 "heavy ox" of average size and full of tan
liquor, a weight of 31,500 lbs, or about fourteen tons, exclusive of
apparatus.
The apparatus for carrying the hides may either be constructed of
wood; or it may be partly of wood and partly of metal.
On Sheet 1 of the Drawings, I have shewn the apparatus constructed
of wood, and adapted for tanning 128 "heavy ox" hides at once.
Figure 1 shews a side view of the apparatus, and Figure 2 a longi-
tudinal section of the same. a is the central shaft, mounted on its

page_text: ends in suitable bearings of gun metal. These bearings are carried by
the side walls of a tan pit A, as shewn. The central part of the shaft is
strengthened by surrounding it with a cylinder b, built up from planks
of wood, cemented to one another with marine gluc, in a similar manner
to that in which built up wooden masts have heretofore been constructed.
Between the ends of the cylinder and the shaft a arc wedges c, which
fix the two securely in place. Before these wedges are driven in, the
ends of the cylinder are embraced by strong iron hoops, and compressed
by temporary wedges, and before removing these hoops screw bolts d
are passed through the cylinder and into the shaft, in the manner shewn
at Figure 2, and in the cross section of the shaft at Figure 3. The shaft
having thus been built up with a strengthening cylinder around it is
then turned truly in a lathe. At the ends of the cylinder are two discs e,
which are each built up and fixed to the shaft and to the cylinder, in
the manner shewn at Figure 2, and in the sectional view of one of the
discs shewn at Figure 4. Stay or distance pieces fare also placed at
intervals between the discs at their periphery. Along the circumferenco
of the cylinder are fixed parallel fillets of wood g. By these fillets
sheets of coarse calico or canvas are held at their middle to the
cylinder b, and between the two free ends of the calico or canvas are
placed openwork frames of wood, or basketwork, or boards grooved or
scored on their surfaces. These are at their ends held by cords to the
discs e, so that their inner edge comes within about 10 or 12 inches of
the cylinder, and two of the free ends of the canvas are secured together
so as to envelope them. These canvas covered frames or grooved boards
are for the purpose of keeping the several hides apart from one another,
and for allowing the tan liquor to percolate between them.
F
The cords which connect the frames to the periphery of the discs aro
attached to the frames near their inner ends next the shaft, so that a
certain amount of play is allowed to them that they may adapt
themselves freely. to the sides of the bags of hide or skin. Along each
of the strips g is also fixed a row of screw eyes, to which the hides
which have previously been sewn up into the form of bags are to be
secured, and there are also other rows of screw cyes fixed radially in tho
inner faces of the discs e, to which the ends of the bags are to be
attached. Around the shaft a near each of the discs a tube or passage
is also formed, having a series of short pipes or nipples ¹ projecting
from each. These tubes surrounding the shaft are cachi formed by two
.K

page_text: wooden rings fixed to the shaft at a short distance from one another, and
covered over by metal plates which have the nipples h¹ formed upon
them, and to each of the nipples is secured a short flexible tube /³. A
hole is bored from each of the tubes to the central line of the shaft,
and other holes are formed along the centre of the shaft to meet these
holes. To each end of the shaft is applied a stuffing box through which
a pipo is passed, by which tanning liquor may be supplied to the
tubes h.
The hides after having been suitably prepared for tanning arc, as
before stated, doubled over to form a bag, and a latticework frame
may, if desired, be inserted within them; their edges are then tied
together at intervals by strong twine passed through holes formed in
them, so as to keep the edges of the hide together. Afterwards the
edges are sewn together by a sewing machine, by which the hide is
sewn up into a nearly water-tight bag. Previous to thus sewing up
the hide a small metal tube is inserted near one corner of the bag, and
the edges of the hide are bound around it, and when the bag is sub-
sequently secured to the cylinder 6 this tube is inserted into one of the
flexible tubes 2 of the nipples ³, so that the liquor can be supplied
through it to the interior. Another tube, with a very small aperture
through it may also be similarly sewn into another corner of the bag
to allow air to escape when the bag is being filled with liquor, or a small
puncture might for the same purpose be made through the hide. To
secure the bag to the cylinder 6 and end dises e small bent hooks are
hooked into the ties of twine by which the edges of the hide were held
together previous to being sewn, a strong cord is then threaded
alternately through eyes formed upon these hooks, and through onc
of the rows of radial screw eyes on the discs e and along one of the
wooden fillets which are fixed, as before stated, along the cylinder.
When a bag of hide has thus been fixed to every row of cyes along cach
of the fillets the cylinder will be entirely surrounded by the bags of
hide, and between the several bags there will be a canvas covered
openwork frame, as before described.
A cross section of the cylinder, with some of the bags around it, is:
shown at Figure 3*. Tan liquor of any suitable kind or strength may now
be introduced from both ends of the shaft a into the interior of the
bags, and the shaft be also slowly revolved by a spur wheel k upon it
being driven slowly by a pinion 7; a speed of one half revolution per
2

page_text: minute.for the shaft a will ordinarily be fully sufficient. On the pipes
by which tan liquor is admitted to the two ends of the shaft is a tap m
for cutting off the supply of tan liquor from the elevated cistern in which
the liquor is contained. There is also a branch pipe m², on which is an
outlet tap and another branch pipe m², also fitted with a tap, and leading
to a suction pump. By closing the tap m and opening the tap m¹ at onc
end of the apparatus the tan liquor may be allowed to escape from
every alternate bag, whilst the other bags continue to be distended by
the pressure of liquor within them; when one half of the bags have
thus been emptied they may if desired be put in connection with a
suction pump by opening the tap m², and tan liquor be thus drawn into
them; but in most cases I believe that this will be unnecessary, and
that the tap m³ and suction pump might be omitted.
.
After one half of the bags have been emptied, as above described; the
operation may be reversed and tan liquor be again supplied to these
bags, whilst it is allowed to escape from the bags which were previously
distended. Thus the several bags may be successively emptied and
distended, so that the liquor in addition to being caused to percolato
through the hides is also kept flowing into and out of the bags, and the
bags are continuously shifting their position as they are carried round with
the revolving shaft. The arrangement above described will give to the
bags a certain amount of swaying and movement of the parts, and will
act beneficially to serve the purpose of "handling," as in the old
process of tanning.
I would here remark that in place of the shaft a being of wood it
may be formed of a hollow tube of metal, as shown at Figures 5 and 6,
in which like letters of reference are placed upon the parts which are
similar to those shewn in the previous Figures. Other suitable
arrangements may also be adopted for constructing a shaft capable
of carrying the weight of the bags of hides, together with their contents
of tan liquor.
I would also remark that the tan pit A may either be kept full of
tan liquor or may be kept empty, and simply used for collecting the
liquor which percolates through the bags. In cases also where suction
is used to draw tan liquor into the bags the pit might be made of such
a height that all of the bags might be kept immersed in tan liquor.
In place also of the shaft a being horizontal it might be placed
vertically, although I believe not so advantageously.
j

page_text: I would also remark that in place of the bags of hide being ranged
radially around a central shaft, as above described, some of the
advantages obtained from that arrangement might be obtained by
ranging a number of bags in a straight row, each bag being connected
to a movable supporting bar, and every alternate bag being coupled up
to one liquor supply pipe, whilst the remainder are coupled to another
liquor supply pipe, so that the bags may alternately be emptied and
distended with liquor in the manner before described. Such a row of
bags may be contained in a tank or pit of suitable form and material,
and sufficiently strong to resist the pressure upon it.
The tank may either be of wood, or partly of wood and partly of
metal, and may either be a fixed tank or it may be mounted upon a
shaft, as shewn at Figure 7, so that its ends may alternately be raised
and lowered at the same time that the bags of hide or skin arc
alternately filled and emptied, as before described; this motion will
assist the tanning process by causing a shifting movement of the
several bags of hide or skin, as in "handling," by the old process of
tanning. With this arrangement also tan liquor may be drawn from
the tank into every alternate bag, whilst the others are kept distended
with tan liquor.
Having thus described the nature of my Invention, and the manner
of performing the same, I would have it understood that what I claim
as my improvements in tanning, and in apparatus to be used for this
purpose, is,-
1. The tanning hides, substantially in the manner herein described,
by assembling together a number of hides sewn up into the form of
bags, and with or without movable openwork frames between them,
in such manner that the bags afford support to one another when they
are supplied with tan liquor under pressure..
2. I claim alternately admitting tan liquor to and allowing it to
escape from such an assemblage of bags of hide, one half of the bags
being distended whilst the others are allowed to empty, substantially
as herein described.
3. I claim ranging a number of hides, sewn up into the form of
bags, radially around a supporting shaft, and giving to such shaft a
slow revolving motion at the same time that tan liquor is supplied to
or alternately supplied to and withdrawn from the bags.

page_text: 4. I claim the construction of apparatus to be used when tanning
ides, substantially in the manner herein described.
In witness whereof, I, the said John Evershed, have hercunto
set my hand and seal, this Nineteenth day of December, in the
year of our Lord One thousand eight hundred and seventy-
three.