IMPROVEMENTS IN APPARATUS FOR WITHER- ING AND DRYING TEA LEAF
Year: 1877

page_text: LETTERS PATENT to Thomas Balmer, of Fochabers, in the County of Moray,
Scotland, for the Invention of "IMPROVEMENTS IN APPARATUS FOR WITHER-
ING AND DRYING TEA LEAF."
Sealed the 20th April 1877, and dated the 22nd January 1877.
PROVISIONAL SPECIFICATION left by the said Thomas Balmer at the Office
of the Commissioners of Patents on the 22nd January 1877.
THOMAS BALMER, of Fochabers, in the County of Moray, Scotland.
MENTS IN APPARATUS FOR WITHERING AND DRYING TEA LEAF."
" IMPROVE-
This Invention has for its object the withering or primary partial drying, and the
drying or final drying of tea leaf in a continuous, efficacious, and simple manner,
and by means of improved apparatus whereby time and hand labor are largely
saved.
The improved apparatus to be employed for the withering process comprises a
hollow cylinder of metal or wood, or of metal and wood combined, and placed in an
inclined position. A current of heated air is passed through the cylinder from its
lower to its higher end (or in the opposite direction if found better in practice) and
the fresh tea leaf is fed in at the higher end by any suitable mechanical feeder.
The cylinder is fitted internally with a series of longitudinal flanges which project
from the cylindrical shell a certain distance towards the centre, and which may be
straight, but are by preference curved, as seen in transverse section. The cylinder is
made to rotate about its axis by gearing from any suitable prime mover, and as it
rotates the internal flanges carry round the tea leaf to the upper side, whence it falls
in a continuous shower through the central current of hot air. The inclination of
the cylinder causes the tea leaf to move gradually towards the lower end, and
during the progress along the cylinder each particle is repeatedly dropped through
the heated air current and the withering action is consequently thoroughly effective
and quite uniform in its action. The cylinder may be formed with hollow trunnions
at the ends, by means of which it may be carried in bearings, and through which
the hot air passes, the tea leaf entering at the higher one. If necessary flat rings or
annular diaphragms are fitted at intervals along the cylinder to insure that the air
Price 6d1

page_text: current will proceed along the centre and not along the descending side of the
cylinder, which side is always empty of tea leaf. The withered tea leaf is dis-
charged from the lower end of the cylinder through a door or valve, which is opened
periodically by the gearing.
The final drying of the tea leaf (generally effected after the tea leaf has been rolled,
which operation follows the withering or primary partial drying of the fresh tea
leaf) is to be effected in a rotating cylinder arranged and worked like that herein-
before described for the withering process, but which will not require to be so large
when dealing with the same quantity of tea leaf.
The current of heated air is to be obtained by forcing air by a fan or blower
through pipes heated by a furnace, or in furnace flues, or through a casing through
which the exhaust steam of the engine or steam direct from a boiler is passed, the
air and steam being separated by either of them passing through pipes, or other-
wise, or the air may be heated partly by steam and partly by a furnace. Super-
heated steam, or any suitable inert gas or vapor, may be substituted for the heated
air.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Balmer in the Great Seal Patent Office on the 21st July
1877.
THOMAS BALMER, of Fochabers, in the County of Moray, Scotland.
MENTS IN APPARATUS FOR WITHERING AND DRYING TEA LEAF."
دو
" IMPROVE-
This Invention has for its object the "withering" or primary partial drying, and
the "drying' or final drying of tea leaf in a continuous, efficacious, and simple
manner, and by means of improved apparatus whereby time, fuel, hand labour, and
consequently expense, are largely saved.
And in order that my said Invention may be fully understood I now proceed to
particularly describe and ascertain the system, mode, or manner in or under which
the same may be practically carried into effect, reference being had to the accom
panying Sheet of Drawings and to the letters and figures marked thereon, and
wherein similar letters of reference indicate corresponding parts in all the figures in
which they occur, that is to say,-
Figure 1 is a side elevation of my improved tea withering and drying apparatus;
Figure 2 is a plan of the same; Figure 3 is a longitudinal section of the withering
cylinder; and Figure 4 is a transverse section of the drying cylinder, but on a larger
scale than Figure 3; Figures 5 and 6 are respectively longitudinal and transverse
sections of the feed hopper for delivering the tea to the cylinders, showing the
means I specially employ for feeding the tea leaf continuously thereto in regulated
quantities.
The cylinder A is that for withering the tea leaf. It consists of a hollow
receptacle of wood, metal, or preferably of thin sheet metal, jacketed with felt and
wood, or other equivalent heat non-conducting material. The cylinder A is formed in
moveable longitudinal sections or parts to admit of being washed or otherwise
cleansed when required, as shewn with regard to the drying cylinder at a, a, in the
transverse section, Figure 4. The interior of the cylinder A is provided with fixed
longitudinal projecting shelves or lifters b, b, of a curved figure in transverse section
as shewn at Figure 4, which shelves may be either in continuous or broken,
straight or spiral lines, and also with flat rings or diaphragms c, c, having a passage
through their centre. The cylinder B is that for drying the leaf after the withering
and rolling processes have been completed, it being here explained that the process
of rolling intermediate between the "withering" and final drying and the mechanism
for effecting the rolling are or may be of the kind ordinarily employed, and there-
fore form no part of my present Invention.
The drying cylinder B is constructed in a manner similar to that of the withering

page_text: cylinder A, but is of smaller diameter. Both cylinders are carried by framings C, C,
which may be formed of wood or iron, and are formed at one end with hollow
trunnions d, d, which turn in bearings e, e, in the framing. The other ends of the
cylinders A and B turn on end plates d' (or on rollers) which may be adjusted
vertically by the screw d² (Figure 3) or by any equivalent means, so as to cause the
cylinders to have a greater or less inclination. The feed hoppers D of the cylinders
are formed by preference with a feed wheel g in their interior for regularly and con-
tinuously feeding in the tea leaf and the rolled tea to the cylinders. Each of the
wheels g is divided into radial chambers g¹, g', (Figures 5 and 6,) one of which at a
time comes under the opening of the hopper. Each of the feed wheels g is rotated
by a lever g², urged upwards at intervals during the rotation of the cylinders A and B
by projections g³ formed on each of the said cylinders, and these levers carry at
their extremities pawls gs which acting on the ratchet wheels g* fixed on the axis
of the wheels g impart to them a slow intermittent rotation. The rotation of the
cylinders A and B is effected by belting and toothed gearing h, h, h, driven from
the steam engine or other motor E. Air is supplied to the cylinders A and B from
the fan F, also driven by belting f from the engine, the said air being heated on its
way to the cylinders by passing it through the pipe G into a coil of pipes H in the
smoke box I of the furnace I (or through a coil of pipes in a separate furnace) and
thence through the pipe J to the heater K, which may be heated by the exhaust
steam from the engine or by steam direct from the boiler being led thereinto. Thus
the air is further heated or it may be heated by any of or by all of these methods,
after which it passes by the pipes L, L', to the cylinders, through the centre of which
it is caused to flow by the flat rings C hereinbefore described, and escapes by suit-
able openings in the ends thereof. The pipes L, L, and the open pipe L³ are
furnished with valves 1, l, by which the volume of air sent into either cylinder may
be regulated and the surplus air allowed to escape.
The temperature of the hot air current may be regulated by lessening or enlarging
by means of shutters the openings by which the outside air is admitted into the
fanner, and thus increasing or diminishing the volume and speed of the air sent
through the heating apparatus, and also, if necessary, by using larger or smaller
pulleys for driving the fanner. The air for the withering cylinder may be further
tempered by opening a valve in the pipe L2, leading from the cold air pipe C to the
pipe L. The temperature of the air entering the cylinders may be denoted by
thermometers placed in the air pipes at their entrance to the cylinders. The
cylinders A and B are placed at inclinations to the horizon as shewn at Figures 1
and 3. The feed hopper and hot air inlet of the withering cylinder are at its higher
end, an outlet i being provided near the lower end for the exit of the tea leaf, and
the lower end being perforated or having suitable openings for the escape of the
hot air. The drying cylinder B has its feed hopper at its higher end and its hot air
inlet at its lower end. The lower end of this cylinder is provided with an exit
door (Figure 4) for the escape or discharge of the dried tea, which door will fall
open at intervals as it is carried round by the revolution of the cylinder to the lower
side, and is shut by a projection on the framing acting against the projection i² on
the said door, or by any other suitable means. The end plate at the upper end of
the cylinder B is perforated for the escape of the hot air.
The action of the apparatus is as follows:-The whole apparatus being set in
motion by the engine E, air is driven by the fan F through the pipe G to the
heater H, thence through the pipe J, to be further heated by the heater K, and
from thence through the pipes L, L, to the withering and drying cylinders A and B.
Tea leaf is fed to the revolving withering cylinder A through the hopper D, either
by hand or by a mechanical feeder, the leaf being received from the hopper into one
of the chambers g¹ of the feed wheel g, and being carried round by the feed wheel g,
as herein-before described, is discharged into the withering cylinder, each chamber
of the feed wheel g in its turn presenting itself to the opening in the bottom of the
hopper, receiving its supply of tea leaf therefrom, and discharging it into the
withering cylinder A. The tea leaf on entering the revolving withering cylinder A

page_text: is carried or lifted up by the curved shelves b, b, and as each shelf rises toward and
descends from its uppermost central position as the cylinder revolves, the leaf falls
from it in a gradual and continuous shower (through the space traversed by the
current of hot air) to the bottom, whence it is immediately again carried up as
before, so that the whole of the leaf in the cylinder is caused to fall through the
hot-air current more than once (nearly twice) each time the cylinder revolves, and
thus it is withered with complete équality, and by reason of the inclination of the
cylinder it eventually, and in such time as may be desired, is made to arrive at the
lower end, when it is discharged at the opening made for that purpose.
I prefer that the hot air should take a course through the withering cylinder in
the same direction as does the leaf, as I believe it will be found in practice that the
leaf will be withered more equally, and that the more delicate leaves and parts of
leaves will be less apt to be over dried and made crisp when the leaf, as itself gets
softened and flaccid, is made to travel away from the hot current; by constantly
supplying the hopper with leaf the withering process is continuously carried on.
The diaphragms c, c, cause the heated air in its passage through the cylinders to
keep a central course, through which the leaf is continuously falling, and thus it is
completely utilized and acts thoroughly upon the leaf. The leaf when withered is
taken to the rolling or curling machine, which may be driven from the drum e¹ on
the shaft of the engine E.
I have not shewn this curling machine in the annexed Drawings, for the reason
that, as herein-before mentioned, it constitutes no part of my Invention. After the
leaf is rolled or curled it is fed by a feed wheel g, as is the case in the withering
cylinder, or by hand through the hopper D into the drying cylinder B, and is carried
up and falls through the heated air therein in a manner similar to that herein-before
described with reference to the leaf in the withering cylinder A, but in this drying
cylinder B the leaf takes the reverse course from and is made to travel toward and
meet the hot air, so that as the tea itself gets drier it is continuously entering into
still hotter and drier air, and as the cylinder is set at such an inclination that the
tea reaches its lower end in the proper time required to dry it completely it follows
that it is only subjected to the action of the air current, when in its hottest and
driest state, for the shortest time possible.
As the tea in travelling into the hotter and drier part of the air current is
simultaneously leaving and passing out of the damper and more saturated portion
of it, which is itself flowing in the opposite direction, it will, by so repeatedly
falling through the air current, be thoroughly ventilated and be dried with perfect
equality, and there will be no danger of bleaching the tea, as the current of hot air
will be regulated to travel at such a speed as that it will pass out of the cylinder
before it is quite saturated with moisture, but not before its drying power has been
utilized as far as desirable. The dried tea is eventually discharged from the cylinder
by the discharge outlet herein-before mentioned.
By shifting the belting of either cylinder on to its loose pulley it can be thrown
out of action and the other cylinder be used alone.
Having now described and particularly ascertained the nature of my said
Invention, and the system, mode, or inanner in or under which the same is or may
be used or practically carried into effect, I would observe in conclusion that what
I consider to be novel and original and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is, the improved process of
and the general combination and arrangement of apparatus for withering and drying
tea leaf herein-before described, that is to say, withering and drying tea leaf by
means of revolving inclined withering and drying cylinders formed in longitudinal
sections, and provided with curved longitudinal elevating shelves or lifters and air-
directing rings or diaphragms, and with a regulating feed wheel and hopper at their
upper ends, and with discharge doors or openings at their lower ends, air being
driven by a fan through a heater or heaters into the said cylinders, the whole
working continuously, without interruption, the said air being caused to take a
course in the same direction as that of the leaf, by preference, in the withering

page_text: cylinder, and a course in the reverse direction to that of the leaf in the drying
cylinder, and either cylinder being capable of being used separately, the whole being
arranged and combined substantially as herein-before described and illustrated in the
accompanying Drawings.
In witness whereof, I, the said Thomas Balmer, have to this my Specification
set my hand and seal, this Seventeenth day of July, in the year of our
Lord One thousand eight hundred and seventy-seven.
THO. BALMER. (L.S.)