Improvements in the Method of and Machines for Degreasing Leather.
Year: 1896

page_text: Date of Application, 19th May, 1896-Accepted, 20th June, 1896
COMPLETE SPECIFICATION.
Improvements in the Method of and Machines for Degreasing
Leather.
We, GEORGE EDWARD WRIGHT, of Wollaton, Nottingham, Electrical
Engineer, and WILLIAM MONK, of 428 Alfreton Road, Nottingham, Engineer,
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 :-
Our invention relates to improvements in the method of and machines for
degreasing leather, and the chief features of our improvements are-
First, Employing a warm instead of a cold liquid volatile solvent whereby the
process of degreasing the skins is appreciably accelerated.
Secondly, Immersing the skins in the liquid solvent instead of showering or
spraying the liquid on to the skins as in previous methods. By this improvement
we avoid the streaks and patches constantly caused by the spraying system.
Thirdly, Agitating the skins by a suitable mechanical contrivance during
the degreasing process whereby the grease is caused to leave the leather more
rapidly.
Fourthly, Admitting air under pressure so as to cause a constant movement
and agitation of the warm liquid solvent in which the skins are immersed
whereby the fat extracted is uniformly distributed throughout the entire volume
of the solvent.
Fifthly, Causing a thorough and uniform circulation of hot air through the
skins during the drying process in such a manner as to prevent scorching and
uneven drying.
Sixthly, Employing a separate air heater, circulating pipes and condenser
instead of employing the hot air circulating through the evaporating pan as in
previous machines, and by these means avoiding the use for drying purposes of air
saturated with vapour generated in the evaporating pan.
We carry our improvements into practical effect by means of a machine or
apparatus constructed substantially as hereinafter described with reference to the
accompanying ten sheets of drawings forming part of this Specification.
Figures 1 and 2 are elevations of the machine.
Figure 3 is a plan of the lower part, and Figure 4 is a plan of the upper part
of the machine, and Fig. 4^ is a detail of part of the same.
Figures 5 to 10 are detail views of various parts of the machine.
In the construction illustrated the machine is furnished with two tanks A A' for
the reception of the skins or leather goods to be degreased, so that whilst the
degrcased skins in ore tank are being dried, another series of skins are being
degreased in the other tank.
Each of the tanks A A' is fitted with a suitable lid B shown in the detail views,
Figs. 5 and 6, which is capable of being raised and lowered by any convenient
arrangement of gearing. For example, as illustrated in Figs. 1 and 2, a shaft C¹
is supported in bearings carried by two girders C above the lid B and two
chains C secured at one end respectively to the girders; each chain C² passes
under a grooved pulley C³ mounted on the lid, over a chain wheel C fixed on the
shaft C and round a chain wheel C to a balance weight C. Also fixed on the
shaft C' is a sur wheel C7 which gears with a pinion C8 upon the axis of which is
fixed a sprocket wheel C' actuated by a hand chain C¹º.
The skins A, A, A, Fig. 2, to be treated are suspended by means of spring

page_text: clips or other suitable fasteners from a series of gratings E which run on angle
iron or other suitable fraines A2 connected by links E to the under side of the
lid B, rollers E being mounted on the gratings E to diminish friction and facilitate
the handling of the gratings with the skins.
Any suitable arrangement of mechanism may be employed to impart a recipro
cating movement to the frames A2 and gratings so as to move the skins to and fro
whilst immersed in the solvent. We show for this purpose a crank E³ on a
vertical shaft E which passes through a stuffing box in the lid B and is supported
by standards B₁ on the under side and standards B' on the top side of the lid.
On each shaft E' is a bevel wheel E' gearing with a bevel wheel E on a horizontal
shaft E' supported in brackets secured to the lid. Also mounted on the shaft E
are fast and loose pulleys E" which are driven by a belt, not shown, and so drive
the vertical shafts E and cranks E which by connecting rods E impart a
reciprocating motion to the cross stays of the frames A and so to the series of
gratings E, this motion assisting and accelerating the process of extracting the
grease from the skins suspended from the gratings and immersed in the solvent.
The tanks A. A have suitable pipes controlled by valves D D' for regulating
the ingress and D, D, D', and D the egress of the liquid volatile solvent used in
degreasing the leather placed in the tanks.
The tanks A A' are charged with the liquid volatile solvent from a charging
tank F to which they are counected by means of pipes De D' controlled by
valves D D respectively, see Figs. 2 and 3. The charging tank is supplied with
clean solvent from two reserve tanks G G which are connected together by a
pipe G2 and by a pipe, not shown, at a lower level so that the solvent in each tank
may be at the same height. The charging tank F is also connected to the
tanks G G by a pipe G³ controlled by a valve G' actuated by a hand wheel G,
Figs. 1 and 4, and by a pipe Hi to the delivery side of a pump H. The pump H
is also connected on the suction or inlet side by pipes H H and valves D³ D'
respectively to stand pipes H', see Fig. 4 in plan and Fig. 4 in elevation, placed
one in each tank A A', and by which means two-thirds or other desired pro-
portion of the liquid volatile solvent from either tank can be pumped back into the
charging tank F
The valve D actuated by a hand wheel H, Fig. 4 and Fig. 1, is to break
connection between the pump H and the tanks A A while the pump H is taking
from G a quantity of clean solvent to make up the charge in the tank F equal to
that run off by the valve D' into the evaporating pan L for recovery as hereinafter
described,
The pump H is driven by means of a belt and pulleys I, Fig. 3, and a crank pin
on a disc coupled by a connecting rod 12 to the piston of the pump H, or by
any other convenient arrangement of driving gear.
Inside the tank F we place an arrangement of steam pipes J, or any other
suitable means for heating a charge of liquid solvent prior to running it off by the
pipe D or D' and valve D or D' into the tank A or A' as the case may be.
The
The tanks A A' are connected by pipes L' controlled by valves D D respec-
tively actuated by hand wheels Ds and D° Fig. 2 and Fig. 4, to the steam jacketed
pan L which is preferably fitted with a steam coil and into which the spent solvent
when saturated with grease is run from either tank to be evaporated.
evaporating pan L is connected by pipes M¹ M² to two condensers M M respec-
tively by which the volatile solvent evaporated in the pan L is condensed and
recovered and returned through pipes M M to the pipe G'and reserve tanks GG'.
A fan W is connected on the bottom side of the condensers M³ and M' by
pipes Wand W and draws air from the pan L to the condensers and discharges
it by a pipe W³ into the pan L again, thereby assisting vapour to pass through M
and M. The grense separated from the spent solvent in the evaporating pan L
is run off through a cock L, shown in Fig. 1 in elevation and Fig. 3 in plan.
In addition to the condensers M³ M which recover the solvent evaporated in
the pan L we also employ a separate condenser N for recovering the solvent

page_text: absorbed by the hot air circulated through the saturated goods during the drying
process after the solvent has been run out of the tank A or A'. This condenser N
is connected by pipes N', N, N³, and valves N, N', actuated by chain and
wheels N and N with the tanks A A¹ and on the bottom side by a pipe N with
a fan O and heater P which is connected by pipes O' and O' and valves O' and
the rectangular branch 06 to the tanks A and A¹; and by a pipe O' and valve O
to the charging tank F. The fan O is driven by a belt and pulley as shown or in
any other convenient manner and the hot air circulated by it passes into one end
of the tank A or A as the case may be, above the suspended skins and following
the course indicated by the arrows in Fig. 6, passes downward at the other end
through a perforated zinc or other suitable baffle plate A³ which distributes the
hot air evenly among the goods which are suspended at an equal and known
distance from each other, this arrangement preventing any skin coming in contact
with another which was a defect in previous methods of hanging goods on skewers;
the hot air passes out by valves N and N° and by pipes N2 N3 and N¹ into the
condenser N where the solvent absorbed by the hot air in its passage through the
saturated goods is recovered, and drained off into the reserve tank G or G¹, the air
being drawn again through the heater P by the fan O and passing thence into the
tanks A A through the goods as before described.
To keep the condensers M³ M* and N cool, a pump Q, shown in Fig. 1, driven
by a belt and pair of pulleys Q' or otherwise as convenient, is employed to circulate
cold water through the condensers the water being supplied to the condenser N by
a pipe Q and passing thence by pipes Q³ Q into the condensers M* M* from
which it is discharged through pipes Q Q respectively.
To agitate and maintain the temperature of the liquid volatile solvent in which
the skins are immersed during the degreasing process we employ perforated pipes R
inside each tank A A¹ through which pipes air under pressure is forced by an air
pump S through a heater T. The air drawn from the top of the tank A or A¹
above the level of the liquid solvent therein through a pipe S¹ controlled by
valves Sinto the air pump S whence it is forced through a pipe S³ into the
heater T and then, raised to the desired temperature, passing through a valve S,
Fig. 4, it is forced through the perforated pipes R into the tank A or A¹ thus
completing the circuit.
Having specified the several parts of the machine we will now proceed to
describe how we carry out the operation of degreasing leather therein.
We first release the fastenings B³, Figs. 6 and 8, by which the lid B is made
airtight and retained in position on its tank A or A' (for convenience of description
we will suppose that the operation is in this case to be carried out in the tank A).
We then by means of the hand chain C and gearing described, raise the lid B
clear of the tank A and draw the gratings E on their rollers E out of the
frames A and take off the goods which we will suppose have already been
degreased. These gratings are then put aside to be re-filled with skins during the
time that the goods are drying in the other tank A' and we take a third set of
gratings E which have been filled with skins whilst the goods were drying in the
tank A and slide them into their places on the frames A. This having been done
the lid is lowered and secured by the fasteners B and the following valves are
closed, the valve D' to shut off communication with the evaporating pan L, the
valve O to shut off the hot air from the fan O and heater P and the valves N* N*
shutting off the condenser N from the tank A. Then the valve D is opened to
allow the charge of warm liquid volatile solvent in the charging tank to flow
into the tank A and the valve O is opened to allow the air displaced by the solvent
to pass from the tank A through the pipe O into the tank F. When the charge
of solvent has entered the tank A the valve D is closed, the valves S and S are
opened, the air pump S is set in motion thereby circulating warm air through the
perforated pipes R as before described, and the belt is put on the fast_pulley E*
so as to drive the shaft E' and agitate the frames A' with the gratings E and the
skins immersed in the solvent.

page_text: This process is continued say for an hour or more or less as required, until the
skins are completely degreased, then the belt is shifted from the fast to the loose
pulley E to stop the rotation of the shaft E' and the oscillation of the frames A
and gratings E and the pump S is also stopped to interrupt the air circulation
through the perforated pipes R.
On completion of the degreasing process and after an interval of at least ten
minutes to allow time for the grease and solid matters to settle somewhat in the
tank A, the valve D' actuated by the hand wheel H is opened and the pump H
started and two-thirds of the liquid solvent in the tank A pumped back to the
charging tank F until the solvent is reduced to the level of the top of the stand
pipe H', then the valve D' is closed and the valve D is opened and the one-third
charge of solvent remaining in the tank A is ran off into the evaporating pan L;
the valve D is then closed, and the solvent is then evaporated in the pan L
the grease and solids separated and collected, the vapour condensed in the
condensers M M and the recovered liquid solvent thus purified is run off through
the pipe G2 into the reserve tank G or G¹.
Whilst the separation of the grease and the purification and recovery of the
liquid volatile solvent is taking place the valves N' and N are opened and the
fan O set in motion and air heated by the heater P is circulatel through the tank A
flowing evenly and softly between and about the suspended skins and gradually
absorbing the liquid volatile solvent with which they are saturated.
As the saturated air passes through the condenser N the vapour is condensed
into liquid and the volatile solvent recovered in that form, the purified air passing
forward to the tank A after being re-heated in the heater P.
This air circulation and drying process is continued for say an hour or an hour
and a half until the skins are quite dry and all the solvent has been recovered.
The valves N N are then closed, the lid B is released and the gratings E with
the degreased skins are then removed from the tank A. and a fresh set substituted
in the manner described.
We wish it to be clearly understood that we do not limit ourselves to the several
details nor to the particular construction or arrangement of the parts herein shown
and described as the same may be considerably varied and modified without
departing from the essential features of our invention hereinbefore specified and as
hereinafter pointed out in the claims. For example, we might employ a single
tank and appurtenances but we prefer to duplicate the tanks and connections so
that whilst the degreased skins in the tank A are being dried another series of
akins may be degrease in the tank A' and vice versa. Again we might employ
one supply tank instead of the two tanks G G and instead of the pumps, fans
and condensers employed we might employ any suitable equivalents.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:-
1. The improved method of degreasing leather consisting in its essential features
in immersing the skins in a warm liquid volatile solvent, preferably agitating the
skins or the solvent or both during the degreasing process, causing a thorough,
even and uniform circulation and distribution of hot air during the drying process
and separating the grease and recovering the volatile solvent by evaporation and
condensation, all substantially in the manner and for the purposes herein set
forth.
2. An improved machine for degreasing leather, said machine having the
following essential elements in combination (a) means for charging the tank in
which the skins are treated with warm liquid volatile solvent and means for
discharging the same, (6) means for suspending and preferably agitating the skins
whilst immersed in the solvent in conjunction with means for agitating the solvent,
(e) means for supplying and circulating warm air and distributing the same among
the skius evenly and uniformly thus drying the saturated skins and absorbing the

page_text: volatile solvent, (d) means for evaporating and con lensing so as to separate the
grease and recover the volatile solvent.
3. The combination with a tank such as A or A', of a movable lid fitted with
sliding frames carrying the gratings or equivalents from which the skins are
suspended at equal distances apart and means for moving said frames during the
degreasing process substantially as herein set forth.
4. The combination with a tank such as A or A' and a stand pipe H' or
equivalent, of a pump and charging tank for the liquid volatile solvent in
conjunction with an evaporating pan and condenser substantially as herein set
forth.
5. The combination with a tank such as A or A', of means for with Irawing air
from above the level of the liquid volatile solvent in the tank and then heating and
forcing the air again into the tank through perforated pipes or equivalents in order
to agitate and aerate the solvent and facilitate the degreasing process substantially
as herein set forth.
6. The combination with a tank such as A or A', of means for circulating hot
air evenly and uniformly through the saturated skins suspended in the tank and
condensing and recovering the volatile solvent containel in the vapour by a
separate condenser having no connection with the evaporating pan or its condensers,
substantially as herein set forth.
7. The several combinations and arrangements of parts embodying our improve-
ments in the method of and machines for degreasing leather substantially as
and for the purposes herein described and as illustrated by the accompanying
drawings.
Dated this 18th day of May 1896.
H. B. BARLOW & GILLETT,
17 St. Ann's Square, Manchester, Agents for Applicants.