Improvements in the Process of Withering or Limping Tea Leaf in the Course of its Manufacture into Black Tea, and in Apparatus therefor.
Year: 1894

page_text: Date of Application, 22nd May, 1894
Complete Specification Left, 5th Nov., 1894-Accepted, 8th Dec., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Process of Withering or Limping Tea Leaf in
the Course of its Manufacture into Black Tea, and in Apparatus
therefor.
I, SAMUEL CLELAND DAVIDSON of Sirocco Works, Belfast, Ireland, Merchant,
do hereby declare the nature of this invention to be as follows:-
The withering or limping of tea leaf is the first process to which the freshly
plucked leaf is subjected in its manufacture into black tea, and as hitherto effected
this process has consisted in partially drying the leaf, the ordinary method of doing
which has been to expose it in thinly spread layers to the drying action of the sun's
rays, or of the atmosphere until about 20 to 50 per cent. more or less of the
moisture naturally contained in the leaf is evaporated, whereupon the leaf is then
found to have attained the required limp and flaccid condition which is ordinarily
known (and which for brevity of description is hereinafter referred to) as
"withered," and in order to hasten sufficient evaporation to produce this withered
condition it has hitherto been a very general practice to spread the leaf thinly
on trays or racks in airy sheds or rooms and by means of powerful ventilating fans
to cause large volumes of dry and slightly heated air to pass through and between
the layers of leaf therein, and the current of relatively dry air thus passing
amongst the leaf dries it sufficiently to produce the above described withered
condition; and hitherto it has been considered equivalent to an axiom in the
manufacture of black tea that an evaporation of about 20 to 50 per cent. of
moisture from the fresh leaf is essential to the production of its withered condition,
and that withering and partial drying were therefore, as regards the manufacture
of black tea, practically synonymous terms, but by the hereinafter described improve-
ments relating to the withering of tea leaf its withered condition is better produced
with practically no evaporation of the naturally contained moisture of the leaf,
and the leaf when thus withered produces a better quality of tea than when
withered on the partial drying system hitherto in ordinary use.
According to my invention the freshly plucked leaf is subjected to the warming,
but at same time non-drying, influence of moisture laden or nearly saturated air,
at a temperature of 90° to 100° Fahrenheit whereby the leaf gradually becomes
limp or withered, without at same time appreciably evaporating its naturally
contained moisture, and as the cells of the leaf when thus withered, still remain
well distended with their juices and have also a more delicate succulency of
texture, they are much more easily burst in the rolling process (the next process
of manufacture to which the leaf is subjected after being withered) than the cells of
leaf which has been withered in the hitherto customary way, by the evaporation
of from 20 to 50 per cent. of its moisture, which causes its cellular tissue and the
substances lining the cell walls to become shrunken and leathery in texture.
Accordingly, one of the objects of the invention is to effect the withering of
tea leaf for its manufacture into black tea without at same time evaporating its
naturally contained moisture to any appreciable extent, and the invention comprises
specially constructed apparatus as hereinafter described for carrying out the
improved process.

page_text: According to one method of carrying out the invention the leaf to be withered
is exposed to the action of a current or circulation of moisture-laden warm air
on trays, racks or webs suitably arranged for this purpose in a chamber or com-
partment, the sides, top and floor of which are made as air tight as possible and
one or more inlets are provided for the warm moisture-laden air, which after
circulating amongst the leaf in the withering chamber may pass out therefrom
through one or more outlets or through a heating apparatus and be re-heated and
returned into circulation in the withering chamber.
The trays, webs or racks on which the leaf is spread may be arranged in the
chamber or compartment in superposed order, as in the leaf withering houses
hitherto commonly in use for withering the leaf by the ordinary 20 to 50 per cent.
evaporative system. The trays may be carried in tiers, upon frames or racks,
which may be stationary in the withering chamber or constructed to move on
wheels like railway trucks through a tunnel shaped withering chamber, one before
the other from end to end in consecutive order; or the leaf may be carried through
the withering chamber on endless webs; any of which, or other equivalent
arrangements, combined with a withering chamber or compartment constructed
approximately air-tight as herein before described are, for brevity of description,
hereinafter comprised under and referred to by the term "withering chamber
and when the withering chamber is charged with leaf a current of warm, moisture-
laden air is admitted into it and amongst the leaf spread therein until the leaf
acquires the desired limp or withered condition.
When the trays are carried by trucks caused to move through a tunnel shaped
withering chamber, perforated plates are preferably fitted at the inlet and outlet
ends of the chamber through which the heated moisture laden air has to pass from
the distributing duct and to the collecting duct respectively.
According to another method of carrying the invention into effect, the leaf to
be withered is put into a revolving drum or cylinder, which when the inlet door
for putting the leaf into same is closed, is approximately air-tight except at each
cut of the drum where an opening is provided, one for inlet and the other for
suuiet of the circulating air current passing through same to each of which
openings conduit pipes are connected to conduct the circulating air current from
the cylinder through an air-heating apparatus and fan and back again into the
drum or cylinder. Upon the inside of the cylinder are longitudinal shelves for
lifting the leaf up to the top of the same and then letting it fall again as the drum
revolves. The inlet and outlet ports are preferably connected by a tube of
foraminous material blocked midway by a baffle plate which prevents the air
passing straight through from the inlet to the outlet port and compels the radial
diffusion out from the inlet end of the tube towards the periphery of the drum
and back therefrom to the outlet side of the tube.
The method which is preferably adopted for keeping the warm air in the
withering chamber or the withering drum moisture-laden, like a vapor bath and
at from 90° to 100° Fahrenheit under any climatic conditions is as follows:-
Having constructed the withering chamber or drum as air-tight as practicable
with the exception of the inlet and outlet ports there is attached to each of these
ports conduit pipes for conveying the exhaust air of the withering chamber to and
from an intermediately situated air heating apparatus fitted with a fan which draws
the exhaust air from the withering chamber or withering drum and causes it to
pass through the heating apparatus and back again into the withering chamber or
withering drum.
As it is therefore the same air that is thus circulated over and over again
through the withering chamber or drum, it is self evident that it will rapidly get
so fully charged or saturated with vapor off the leaf that is being withered that
it will soon become incapable of absorbing any further moisture therefrom, and as
this mixture of air and vapor is an effective conveyor of heat, it acts very
satisfactorily in carrying the heat from the air heater into the withering chamber
and keeping it up to the required temperature of 90° to 100° Fahrenheit. Any

page_text: arrangement of air heating apparatus such as steam or hot water pipes or air
heating stoves may be used for heating the circulating air current.
The relative position of the air heating apparatus to the withering chamber or
withering drum is not important, and when desired it may be placed within the
withering chamber, in which case it may be so arranged that the relative cooled
air thereof is conducted by suitable conduit pipes to the base of the air heating
apparatus and the heated air conducted from top of it up to near the ceiling of
the withering chamber by means of an air chimney, so that a self-acting circula-
tion is thus created, and the chamber having been rendered as air tight as practicable
all round, the same air will thus be heated and passed through the leaf over and
over again, and will consequently soon become vapor-laden through getting
charged with moisture off the leaf, while at same time sufficient heat is imparted
to it to keep the temperature throughout the chamber at 90° to 100° Fahrenheit.
Another method which may alternatively be employed to produce the above
described vapor-bath condition of the air in the withering chamber or drum is to
continuously propel into the withering chamber or drum, fresh, warm air charged
with moisture by having sufficient steam injected into it to produce the necessary
degree of saturation, or by passing it through a finely atomized water spray, or
through any wetted porous material or substance, such as wet cotton wool, or wet
tea leaf in the process of being dried after being rolled, and allowing an equivalent
quantity of this air to escape through exhaust ports provided in the withering
chamber or drum.
In either of the above described methods of warming the leaf in the withering
chamber or withering drum by means of warm saturated air very little evaporation
of the naturally-contained moisture in the leaf can take place, and when the heat
of the chamber or drum is in this way continuously maintained at 90° to 100°
Fahrenheit the leaf soon begins to soften and become limp, and eventually assumes
a much more flaccid condition than if it had been withered on the old system by
allowing it to become from 20 to 50 per cent. dried by the action of dry air, or of
the sun's rays.
Dated this 22nd day of May 1894.
J. C. MEWBURN & ELLIS,
55 & 56, Chancery Lane, London, Patent Agents.
COMPLETE SPECIFICATION.
Improvements in the Process of Withering or Limping Tea Leaf in
the Course of its Manufacture into Black Tea, and in Apparatus
therefor.
I, SAMUEL CLELAND DAVIDSON of Sirocco Works, Belfast, Ireland, Merchant,
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 withering or limping of tea leaf is the first process to which the freshly
plucked leaf is subjected in its manufacture into black tea, and as hitherto effected
this process has consisted in partially drying the leaf, the ordinary method of doing
which has been to expose it in thinly spread layers to the drying action of the
sun's rays, or of the atmosphere until about 20 to 50 per cent, more or less of the
moisture naturally contained in the leaf, is evaporated, whereupon the leaf is then
found to have attained the required limp and flaccid condition which is ordinarily
known (and which for brevity of description is hereinafter referred to) as
"withered," and in order to hasten sufficient evaporation to produce this withered
condition it has hitherto been a very general practice to spread the leaf thinly on

page_text: trays or racks in airy sheds or rooms and by means of powerful ventilating fans to
cause large volumes of dry and slightly heated air to pass through and between the
layers of leaf therein, and the current of relatively dry air thus passing amongst
the leaf dries it sufficiently to produce the above described withered condition;
and hitherto it has been considered equivalent to an axiom in the manufacture of
black tea that an evaporation of about 20 to 50 per cent. of moisture from the fresh
leaf is essential to the production of its withered condition, and that withering and
partial drying were therefore, as regards the manufacture of black tea, practically
synonymous terms, but by the bereinafter described improvements relating to the
withering of tea leaf its withered condition is better produced with practically no
evaporation of the naturally contained moisture of the leaf, and the leaf when thus
withered produces a better quality of tea than when withered on the partial drying
system hitherto in ordinary use.
According to my invention the freshly plucked leaf is subjected to the warming,
but at same time non-drying, influence of moisture-laden or nearly saturated air,
at a temperature of 90° to 100° Fahrenheit whereby the leaf gradually becomes
limp or withered, without at same time appreciably evaporating its naturally
contained moisture, and as the cells of the leaf when thus withered, still remain
well distended with their juices and have also a more delicate succulency of
texture, they are much more easily burst in the rolling process (the next process
of manufacture to which the leaf is subjected after being withered) than the cells
of leaf which has been withered in the hitherto customary way, by the evaporation of
from 20 to 50 per cent. of its moisture, which causes its cellular tissue and
the substances lining the cell walls to become shrunken and leathery in texture.
Accordingly, one of the objects of the invention is to effect the withering of
tea leaf for its manufacture into black tea without at same same time evaporating
its naturally contained moisture to any appreciable extent, and the invention
comprises specially constructed apparatus as hereinafter described for carrying out
the improved process.
According to one method of carrying out the invention the leaf to be withered
is exposed to the action of a current or circulation of moisture-laden warm air on
trays, racks or webs suitably arranged for this purpose in a chamber or com-
partment, the sides, top and floor of which are made as air tight as possible and
one or more inlets are provided for the warm moisture-laden air, which after
circulating amongst the leaf in the withering chamber may pass out there-from
through one or more outlets or through a heating apparatus and be re-heated and
returned into circulation in the withering chamber.
The trays, webs or racks on which the leaf is spread may be arranged in the
chamber or compartment in superposed order, as in the leaf withering houses
hitherto commonly in use for withering the leaf by the ordinary 20 to 50 per cent.
evaporative system. The trays may be carried in tiers, upon frames or racks,
which may be stationary in the withering chamber or constructed to move on
wheels like railway trucks through a tunnel shaped withering chamber, one before
the other from end to end in consecutive order; or the leaf may be carried through
the withering chamber on endless webs; any of which, or other equivalent
arrangements, combined with a withering chamber or compartment constructed
approximately air-tight as hereinbefore described are, for brevity of description
hereinafter comprised under and referred to by the term "withering chamber
and when the withering chamber is charged with leaf a current of warm, moisture-
laden air is admitted into it and amongst the leaf spread therein until the leaf
acquires the desired limp or withered condition.
"
When the trays are carried by trucks caused to move through a tunnel shaped
withering chamber, perforated plates are preferably fitted at the inlet and outlet
ends of the chamber through which the heated moisture-laden air has to pass from
the distributing duct and the collecting duct respectively.
According to another method of carrying the invention into effect, the leaf to
be withered is put into a revolving drum or cylinder, which when the inlet door

page_text: for putting the leaf into same is closed, is approximately air-tight except at each
end of the drum where an opening is provided, one for inlet and the other for
outlet of the circulating air current passing through same to. each of which
openings conduit pipes are connected to conduct the circulating air current from
the cylinder through an air-heating apparatus and fan and back again into the
drum or cylinder. Upon the inside of the cylinder are longitudinal shelves for
lifting the leaf up to the top of the same and then letting it fall again as the
drum revolves. The inlet and outlet ports are preferably connected by a tube
of foraminous material blocked midway by a baffle plate which prevents the air
passing straight through from the inlet to the outlet port and compels the radial
diffusion out from the inlet end of the tube towards the periphery of the drum
and back therefrom to the outlet side of the tube.
The method which is preferably adopted for keeping the warm air in the
withering chamber or the withering drum moisture-laden, like a vapor bath and at
from 90° to 100° Fahrenheit under any climatic conditions is as follows:-
Having constructed the withering chamber or drum as air-tight as practicable
with the exception of the inlet and outlet ports there is attached to each of theso
ports conduit pipes for conveying the exhaust air of the withering chamber to
and from an intermediately situated air heating apparatus fitted with a fan which
draws the exhaust air from the withering chamber or withering drum and causes
it to pass through the heating apparatus and back again into the withering
chamber or withering drum.
As it is therefore the same air that is thus circulated over and over again
through the withering chamber or drum it is self evident that it will rapidly get
so fully charged or saturated with vaper off the leaf that is being withered that
it will soon become incapable of absorbing any further moisture therefrom, and
as this mixture of air and vapor is an effective conveyor of heat, it acts very
satisfactorily in carrying the heat from the air heater into the withering chamber
and keping it up to the required temperature of 90° to 100° Fahrenheit. Any
arrangement of air heating apparatus such as steam or hot water pipes or air
heating stoves may be used for heating the circulating air current.
The relative position of the air heating apparatus to the withering chamber or
withering drum is not important, and when desired it may be placed within the
withering chamber, in which case it may be so arranged that the relative cooled
air thereof is conducted by suitable conduit pipes to the base of the air heating
apparatus and the heated air conducted from top of it up to near the ceiling of the
withering chamber by means of an air chimney, so that a self-acting circulation is
thus created, and the chamber having been rendered as air-tight as practicable all
round, the same air will thus he heated and passed through the leaf over and over
again, and will consequently soon become vapor-laden through getting charged with
moisture off the leaf, while at same time sufficient heat is imparted to it to keep the
temperature throughout the chamber at 90° to 100° Fahrenheit.
Another method which may alternatively be employed to produce the above
described vapor-bath condition of the air in the withering chamber or drum is to
continuously propel into the withering chamber or drum, fresh, warm air charged
with moisture by having sufficient steam injected into it to produce the necessary
degree of saturation, or by passing, it through a finely atomized water spray, or
through any wetted porous material or substance, such as wet cotton wool, or wet
tea leaf in the process of being dried after being rolled, and allowing an equivalent
quantity of this air to escape through exhaust ports provided in the withering
chamber or drum.
In either of the above-described methods of warming the leaf in the withering
chamber or withering drum by means of warm saturated air very little evaporation
of the naturally-contained moisture in the leaf can take place, and when the heat
of the chamber or drum is in this way continuously maintained at 90° to 10,0
Fahrenheit the leaf soon begins to soften and become limp, and eventually assumes
a much more flaccid condition than if it had been withered on the old system by

page_text: Decome from 20 to 50 per cent. dried by the action of dry air, or of
the sun's rays.
The accompanying drawings represent several novel arrangements of apparatus
which have been specially designed for carrying into effect the hereinbefore
described process or method of withering tea.
Figures 1, 2, 3 and 4 show an arrangement by which the invention is carried
into effect by means of a withering chamber fitted with stationary racks for carrying
the leaf upon trays or webs, and with an externally situated air heating stove and
circulating fan, the said fan being driven by belting or otherwise.
Figure 1 is a sectional plan, Figure 2 a longitudinal section on the line a-b of
Figure 1, and Figures 3 and 4 cross sections on the lines cd and e f respectively
of Figure 1. X is a withering chamber over which is shown another similarly
arranged withering chamber X¹. There may be one or more other similar
chambers over the chamber X, or alternatively there may be only the chamber X,
E is an air tight ceiling to the top chamber. Each withering chamber is fitted
with stationary racks K for carrying the leaf to be withered upon trays or webs.
Outside the withering chamber is placed an air heating stove C and fan F which
are connected with the withering chambers by the inflow air conduit pipe A and
the return air conduit pipes B, each pipe being fitted with a box H with ports and
valves or doors for opening and closing the same so as to confine the circulating
air current to either floor as required. When the fan F is set in motion the air
laden with the moisture it has taken up from the leaf is drawn from the withering
chamber through the pipes B and the stove C and is propelled back in a moisture-
laden and heated condition into the same withering chamber through the inflow
pipe A. Dis the stove chimney. The stove which is preferably used and which
is illustrated in these figures is the air heating stove described in the Specification
my Patent No. 2703 of 1889.
of
Figures 5, 6 and 7 illustrate in sectional plan, longitudinal and cross sections
respectively an arrangement by which the invention can be carried into effect in a
withering chamber X or X' fitted with stationary racks K for carrying the leaf
upon trays or webs and with the air heating stove C situated inside the withering
chamber X and working with a self acting draft whereby the required circulation
of moisture-laden heated air is effected. The letters of reference are the same as
those in Figures 1 to 4 and indicate corresponding parts. By means of the valve
boxes H connected with the air inflow and return pipes A and B and of the ports
or doors for opening and closing them the circulating air current can be confined to
either floor as may be required. In order that the fire in the stove may not draw
off for its combustion any of the moisture-laden air in the withering chamber a
pipe G is arranged to supply air to the fire from outside the withering
chamber.
Figures 8, 9 and 10 illustrate in plan, longitudinal section and transverse section
respectively an arrangement for carrying the invention into effect in which the
racks for carrying the leaf are constructed to move on wheels as trolleys or trucks
through a tunnel shaped withering chamber X while submitted to the action of a
current of moisture-laden heated air. It will be seen that the racks K are mounted
on trolleys L which move in consecutive order on rails T in the withering
chamber X. A is the inflow air conduit pipe to the chamber X and B the return air
conduit pipe. C is the heating apparatus through which the return air passes
and F is the fan for continuously circulating the air through the pipe A, withering
chamber X and pipe B, and back again through the pipe B to the withering
chamber. P P are perforated plates through which the heated moisture-laden air
has to pass from the distributing duct O to the withering chamber and Pi Pare
similar plates through which the air is exhausted back into the collecting duct O'
at the outlet end of the chamber and thence through the return pipe B. The
trolleys Lwith the racks K containing the leaf enter the long tunnel like withering
chamber X at the entrance doors R which are made preferably to open inwards so
that when a trolley is pushed along the rails T sufficiently far into the withering

page_text: chamber to clear the doors R and allow of their being closed again it will also be
clear of the direct inflow of the air current froin the distributing duct O and the
space here left enables the air currents to blend and mix uniformly before being
passed along over the leaf on the trays carried on the trolleys in its flow through
same to where the outlet air ducts O₁ are situated. The outlet doors S are
preferably made to swing outward. When the trolleys are drawn out of the
chamber X they can be turned on the turntables N N and be passed along the
return rails to the inlet end of the chamber and on their way they can be unloaded
of the withered leaf and be re-charged with fresh leaf to be withered.
Figures 11, 12, 13 and 14 illustrate another way in which the invention may be
carried into effect. Figure 11 is a plan, Figure 12 a front elevation, Figure 13 an
end elevation and Figure 14 a transverse section of the arrangement. X is a
revolving drum or cylinder forming a withering apparatus mounted and revolving
upon standards to which are attached inflow and return air conduit pipes A and B.
respectively and a fan F for circulating the air from the withering drum through
the pipe B and air heating apparatus C and back into the withering drum. The
drum is revolved preferably by means of friction rollers upon the shaft Y which
shaft may be driven from a countershaft Z' by a belt on the driving pulley Z. A
door or port W is provided for charging or emptying the drum. Upon the inside
of the cylinder a number of longitudinal shelves V are fitted, for lifting the leaf up
to the top of the drum before letting it fall again as the drum revolves. The inlet
and outlet ports are connected by a tube (Figures 12 and 14) preferably
constructed of perforated corrugated sheets or wire web and which is attached to
and revolves with the withering drum. This perforated tube is blocked midway
between the inlet and outlet ports by a baffle plate 9 which prevents the air
passing straight through from the inlet to the outlet port and compels the radial.
diffusion of the air out from the inlet end of the perforated tube towards the
periphery of the drun and back therefrom into the outlet side of the tube;
consequently the leaf in the withering drum is better brought into contact with the
warm moisture-laden air and there is no tendency to carry the leaf in the air
current from the inlet to the outlet port.
A charge of leaf having been placed in the drum, it is made to revolve slowly,
say at the rate of 10 or 12 revolutions per minute; and the fan F is set in motion,
whereby a continuous circulation of air as above described is immediately set up
through the drum and air heater C and as the cylinder revolves the shelves V
continuously carry up the leaf to the top of the drum, where it falls off, so that a
continuous shower of leaf keeps falling through the air current which is passing
through the drum, which air current soon becomes saturated like a vapor bath,
with the moisture of the leaf, the limping or withering of which then takes place
in heated moisture-laden air, which prevents any appreciable evaporation of the
naturally contained moisture of the leaf.
Figures 15, 16 and 17 illustrate another way in which the invention may be
carried into effect. Figure 15 is a longitudinal section, Figure 16 an end elevation
and Figure 17 a plan of the arrangement.
The leaf to be withered is carried
through the withering chamber X upon an endless web consisting of flat or dished
perforated plates or woven wire trays, a, which are pivoted to and move forwards
and backwards in the withering chamber by, endless bands or chains passing round
two or more returning wheels.
The machine or apparatus which is preferably used for this purpose, is that
described in the Specification of my Patent No. 2046 of 1892. The leaf is fed into
the machine through the feed hopper c and is discharged by means of the shoot d.
The endless chains and webs are moved by the sprocket wheels b, which may be
driven by any suitable arrangement of gearing as described in the Specification
just mentioned.
The fan F draws the air from the withering chamber X through the air duct O.
and heating apparatus C and propels the same air back into the withering chamber
through the inflow air conduit pipe A.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The process or method of withering or limping tea leaf during its manufacture
into black tea, which consists in causing an artificially induced or mechanically
moved current of air saturated or nearly saturated with aqueous vapor or steam to
flow or circulate through or amongst the leaf, at a temperature of approximately
90° to 100° Fahrenheit, whereby a moist warmth is imparted to the leaf which
efficiently limps or withers it, without at same time permitting any practical loss by
evaporation of the moisture contained in its cells, and the preservation of which
moisture in the cells of the leaf renders the subsequent processes of its manufacture
into black tea more easily performed, and a better quality of black tea obtainable
therefrom, all substantially as hereinbefore described.
2. In the withering or limping of tea leaf by means of an artificially produced
current of air saturated or nearly saturated with aqueous vapor, as hereinbefore
described and as referred to in Claim No. 1, the production and maintenance of the
combined conditions of saturation and warmth of the air used for the purpose, by
having the chamber or compartment, or revolving drum, in which the leaf is being
withered, made approximately air tight in respect of the outside atmosphere to
prevent any of the contained air escaping therefrom, to the outside atmosphere, or
vice versa, and by circulating the thus confined air over and over again by means of
a fan or other equivalent air propelling appliance, or by an induced current caused
by the action of heat operating through conduit pipes in or connected with the
chamber or otherwise through the chamber or compartment or revolving drum and
amongst the damp leaf therein, and through any suitable air-heating appliance or
apparatus connected therewith, so that the moisture rising from the leaf cannot
escape from, and is consequently retained in, the air of the chamber or compartment,
or revolving drum, whereby a vapor-bath-saturation of the air therein is produced
and maintained in combination with sufficient warmth to effect the withering of the
leaf, all substantially as hereinbefore described.
3. The arrangement of parts constituting the apparatus as represented in
Figures 1 to 7 for withering or limping tea leaf by means of a current of warm,
moisture-laden or saturated air caused to circulate amongst the leaf in the withering
chamber, all substantially as and for the purpose herein before described.
4. The arrangement of parts constituting the apparatus as represented in
Figures 8 to 10 for withering or limping tea leaf consisting of a tunnel shaped
withering chamber, with trolleys and carrying racks for the leaf trays caused to
move through it on rails, in conjunction with means for maintaining a current or
circulation of warm, moisture-laden or saturated air amongst the leaf while in the
said chamber, all substantially as and for the purpose herein before described.
5. The arrangement of revolving drum or cylinder and parts constituting the
apparatus as represented in Figures 11 to 14 for withering or limping tea leaf by
means of a current of warm, moisture-laden or saturated air caused to circulate
amongst the leaf in the withering drum or cylinder, all substantially as and for the
purpose hereinbefore described.
6. In the revolving drum or cylinder as referred to in Claim 5, the employment
of a perforated or wire web connecting tube between the inlet and outlet ports in
the opposite ends of same, with a baffle plate in the tube, midway between the two
ports to prevent the air from passing in a direct line between the inlet and outlet
ports and compel its radial diffusion out from the inlet end of the perforated tube
towards the periphery of the drum, and back therefrom into the outlet side of the
tube, whereby. an otherwise existing tendency of the leaf to be carried by the air
current from the inlet over to and accumulate against the outlet port, is obviated,
all substantially as hereinbefore described.
7. The arrangement of parts constituting the apparatus as represented in
Figures 15, 16 and 17 for withering tea leaf, consisting of a withering chamber in

page_text: which the leaf is carried upon endless webs of pivoted plates or trays, in conjunction
with means for maintaining a current or circulation of warm, moisture-laden or
saturated air amongst the leaf in the withering chamber, all substantially as and
for the purposes hereinbefore described.
Dated this 3rd day of November 1894.
J. C. MEWBURN & ELLIS,
55 & 56, Chancery Lane, London, Patent Agents.