IMPROVEMENTS IN TANNING AND IN THE MACHINERY AND APPARATUS TO BE EMPLOYED THEREIN.
Year: 1867

page_text: LETTERS PATENT to Sterling Bonsall, of Philadelphia, United States of
America, but now residing in Aldersgate Street, in the City of London,
for the Invention of "IMPROVEMENTS IN TANNING AND IN THE MACHINERY
AND APPARATUS TO BE EMPLOYED THEREIN.
Sealed the 21st January 1868, and dated the 23rd July 1867.
PROVISIONAL SPECIFICATION left by the said Sterling Bonsall at the
Office of the Commissioners of Patents,, with his Petition, on the
23rd July 1867.
I, STERLING BONSALL, of Philadelphia, United States of America, but now
residing in Aldersgate Street, in the City of London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN TANNING AND IN THE
MACHINERY AND APPARATUS TO BE EMPLOYED THEREIN," to be as follows:-
This Invention relates to certain improvements in tanning and in the
machinery and apparatus to be employed therein, the object being to secure
more effectively as rapid and complete an action of tannic acid or other acid
employed on the central parts of the hide, at the same time securing a proper
expansion and filling of the pores of the hide.
By the ordinary process the action of the liquor is first on the outside pores
of the hide, the gelatin is at once acted upon, the pores are filled up, and the

page_text: outside almost as fully tanned as is necessary, consequently the liquor must
first soak through the pores that are already filled, and as the process increases
and the outside becomes denser the time lengthens and the soaking or
absorption becomes slower and slower as the liquor has to find its way through
the increased resistance, all of which is avoided when we can find a means of
tanning the centre as fast, and in fact almost at the same time as the outside
is tanned. The work can be done by chemicals or by any process, but by this
Invention pure bark liquors only are intended to be used in the same manner and
without much change in the ordinary apparatus. Hydrostatic pressure is com-
bined in this plan with agitation of liquors in a closed vessel without handling
the hides. The vat consists of a square or oblong square receptacle braced with
uprights or retainers and cross bars arranged in fours and secured with wedges,
and forming frames and tightening the vat, but which are easily removed.
The lid rests on an elastic packing forming an air-tight joint; the hides are
hung across the vat on supports or bars; a pipe or nozzle is inserted in the lid,
and is provided with a stop-cock. At the lower part of the vat a rotating dash is
arranged; it is set on an axle or shaft which is turned by a band on a pulley
keyed to the shaft outside the vat, the shaft being secured by a packing or
stuffing box arrangement through which the axle or shaft passes; a man-hole
is formed on the top of the vat, through which the liquors are inserted and
the hides inspected.
The operation is as follows:-Having lined and bated or sweated the hides
in the usual manner they are suspended across the vat on the bars, the vat is
filled with liquor, and the lid placed in position and wedged down, then a hose
is attached to the pipe or nozzle, and with a small force pump placed in a
bucket of liquor such an extra amount of liquor is forced in as will put on
what pressure is required, say from 5 to 10 pounds to the square inch, then
the stop-cock is turned and the pressure retained, one force pump will do for
all the vats, motion is then given to the dasher by the pulley, and this is kept
up either all day, or day and night, as the yard may be running, either by steam
or water power, access is had to the holes by the man-hole; the lid is not
taken off until the hides are tanned and all handling of the hides is avoided.
As the chemical change or action of tannic acid on gelatine is almost
instantaneous, it follows that it is only necessary to bring them together to
accomplish the tanning of the hide, but as too great strength of acid or liquor
is not desirable the weak liquors are put in first, and the strength gradually
increased as well as the pressure, using in all on sole leather about 13 to 15
runs; by these means the gelatin is gradually changed, the pores expanded, and
thoroughly filled. The dasher being in motion draws down the spent liquor

page_text: from the top, throws up the stronger liquors from the bottom, and keeps up a
constant agitation from end to end, and, in fact, in all parts of the vat; this
keeps a uniform strength of liquor to all parts of the hides, and makes a more
even grain, free from kinking. This arrangement of rotating dash located in
the bottom of the vat is the best for keeping a thorough agitation of liquor
throughout the vat, which may be used either with or without pressure.
It is intended to claim the apparatus either combined with pressure and
agitation, or the pressure and agitation separately, for the cover or lid may be
removed so as to operate in a closed or open vessel as convenient, or the dasher
may be placed in the ordinary vats and worked by a pulley and strap within
the vat.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Sterling Bonsall in the Great Seal Patent Office on the
23rd January 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, 1, STERLING
BONBALL, of Philadelphia, United States of America, but now residing in
Aldersgate Street, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of July, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of
Her reign did, for Herself, Her heirs and successors, give and grant me,
the said Sterling Bonsall, Her special licence that I, the said Sterling Bonsall,
my executors, administrators, and assigns, or such others as I, the said
Sterling Bonsall, my executors, administrators, 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 AND IN THE MACHINERY AND APPARATUS TO BE EMPLOYED THEREIN,"
upon the condition (amongst others) that I, the said Sterling Bonsall, my
executors or administrators by an instrument in writing under , 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 per-
formed, 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 -**
Letters Patent.

page_text: NOW KNOW YE, that I, the said Sterling Bonsall, do hereby declare the
nature of my Invention, and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
My Invention relates to certain improvements in tanning and in the
machinery and apparatus to be employed therein, the object being to secure
more effectively as rapid and complete an action of tannic acid or other acid
employed in the central parts of the hide, at the same time securing a proper
expansion and filling of the pores of the hide.
By the ordinary process the action of the liquor is first on the outside pores
of the hide, the gelatin is at once acted upon, the pores are filled up, and the
outside almost as fully tanned as is necessary, consequently the liquor must first
soak through the pores that are already filled, and as the process increases
and the outside becomes denser the time lengthens, and the soaking or
absorption becomes slower and slower, as the liquor has to find its way through
the increased resistance, all of which is avoided when a means can be found
of tanning the centre as fast, and, in fact, almost at the same time, as the
outside is tanned. The work can be done by chemicals or by any process, but
by this Invention pure bark liquors only are intended to be used in the same
manner and without much change in the ordinary apparatus. Hydrostatic
pressure is combined in this plan with agitation of liquors in a closed vessel
without handling the hides.
In order that my said Invention may be completely understood I annex
the accompanying Drawings, in which Fig. 1 represents the vat filled, closed,
and ready for use; Fig. 2 being a longitudinal vertical section of the same,
the vat is made of strong timbers to withstand the pressure, and can be used
in a room, or can be put in a pit and cemented or puddled in the ordinary
manner; Fig. 3 is an end view shewing the pulley E of the agitator.
A represents a vat; A¹ a lid resting on an elastic packing a, a, forming
an air-tight joint; the hides are hung across the vat on supports or bars B, B,
shewn in Fig. 2; C, C, are the upright braces or retainers which are connected
together in fours by pins and wedges, forming frames bracing and tightening
the vat, but easily removed; D is a pipe or nozzle inserted into and passing
through the lid A', and provided with a stop-cock D¹; E is a dasher (shewu
in Figure 2) turned by a band placed around the pulley E on the outside of
the vat; this joint is secured by a packing or stuffing box arrangement, through
which the axle passes; F¹ is a man-hole through which the liquors are put in
the vat and the hides inspected.
The operation of the apparatus is as follows:-Having lined and bated
or sweated the hides in the usual manner I suspend them across the vat on

page_text: the bars B, B, fill the vat with liquor, put on the lid A', wedge it down, then
attach a hose to pipe D, and with a small force pump placed in a bucket of
liquor I force in such an extra amount of liquor as will put on what pressure
1 require, say from 5 to 10 pounds to the square inch; I then turn the stop-
cock D¹ and shut in or retain this pressure; one force pump does for all the
vats; motion is then given to the dasher E by the pulley, and this is kept up
either all day, or day and night, as the yard may be running either by steam
or water power; access is had to the hides by a man-hole F in the top of
the vat, through which the liquor is changed and the hides inspected.. The
lid is not taken off until the hides are tanned. I prefer not to use too great
a degree of pressure, but any required degree of pressure may be applied.
I claim in regard to the aforesaid "Improvements in Tanning and the
Machinery or Apparatus to be employed therein," the following advantages:-
When the pressure is put on, as the liquor cannot be compressed and cannot
enter the pores of the wood, it must enter the pores of the hides, carrying with
it the tannic acid to the centre before the chemical change can fully take
place on the outside, making almost a uniformity of action; the outside cannot
become overtanned or brittle, the fibre is perfectly preserved and will be
found long and with life in it rather than short, and comparatively dried up as
it will often be with bark liquors, or rotten as chemicals will make it. As the
chemical change or action of tannic acid on gelatin is almost instantaneous it
follows that it is only necessary to bring them together to accomplish the tanning
of the hide, but as too great strength of liquor is not desirable I put on weak
liquors at first, and gradually increase the strength of the liquor, and the
amount of pressure used; by this means I gradually change the gelatin, expand
the pores, and fill them thoroughly; the dasher E being in motion draws down
the spent liquor from the top, throws up the stronger liquors from the bottom,
keeps up a constant agitation from end to end, and, in fact, to all parts of the
vat, and keeps a uniform strength of liquor to all parts of the hides, and makes
a more even grain. The dasher or agitator may be used with good effect
without pressure, but I prefer to agitate the liquor when under pressure, as
above described. If it is desired to use the agitator in a very simple manner
I can fix it in the bottom of the pit or vat as now used by means of a suitable
framework, and operate it by a band passing around a pulley attached to the
axle of the dasher and passing over a pulley placed at the top of the vat or
pit, and turned in the usual manner by suitable power, thereby making use
of the dasher or agitator in an ordinary pit or vat, thus with very slight
expense saving the handling of the hides, and agitating the liquor in a more
effctive manner than has heretofore been done.

page_text: Having now described the nature of my said Invention, and the manner in
which the same is to be performed, I would remark that I do not limit myself
to the precise details and configuration of parts I have expressed and shewn,
as the same may obviously be varied or modified without in any degree
departing from the principles on which my Invention is based; but what I
claim and desire to be secured by the herein in part recited Letters Patent are,-
1st. Hanging the hides in a vat and agitating the tanning liquid by means
of a rotary dasher or agitator, substantially as and for the purpose described.
2nd. The application or placing the dasher or agitator entirely in the inside
of an ordinary pit or vat, or a vat constructed for the purpose and working
or operating the same, in order to treat the hides hung in such pit or vats.
3rd. Hanging the hides in a close water-tight vat, and agitating the tanning
liquor by means of a rotary or otherwise moving dasher while the liquor is
under pressure within the said closed vat, substantially as described.
4th. The combination of the water-tight vat A, the dasher E, and a force
pump or other equivalent means of producing pressure within the vat, and
the stop-cock arrangement for retaining the pressure, substantially as described.
5th. The dasher E located in the lower portion of the vat in combination
with the bars B, B, or other equivalent means of hanging, suspending, or
supporting the hides in the vat, either above or below the said dasher, so that
the tanning liquid when agitated by the dasher will freely permeate between
the hides, substantially as herein specified.
In witness whereof, I, the said Sterling Bonsall, have hereunto set my
hand and seal, this Fourteenth day of January, in the year of our
Lord One thousand eighteen hundred and sixty-eight.
Witness,
ALEX. M. PRINCE,
Office for Patents,
4, Trafalgar Square,
Charing Cross,
London, W.C.
STERLING BONSALL. (L.S.)