IMPROVEMENTS IN APPARATUS FOR DRYING AND TREATING TEA AND OTHER MATERIALS
Year: 1884

page_text: COMPLETE SPECIFICATION.
I, JOHN GREIG junior of Edinburgh in the County of Midlothian, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
APPARATUS FOR DRYING AND TREATING TEA AND OTHER MATERIALS" and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This Invention relates to rapidly and more perfectly drying in large quantities
particles or pieces of materials or substances, and it is especially applicable to
drying rolled tea and withering the fresh or green leaf of the tea plant in the
manufacture of tea; to the curing and drying of hops and grain; to the drying of
wet, that is to say, washed feathers and to other analogous purposes.
The Invention consists of apparatus adapted to effect these objects by the use of
air heated to a much higher temperature than can otherwise be employed without
risk of scorching or burning the materials being treated.
The tea or tea leaf or other material or substance being treated is subjected to a
current of the said heated air for which purpose it is placed in compartments in a
drum having a blast fan in conjunction with it and by which the heated air is
forced through the meshes of wire cloth or its equivalent constituting the circum-
ference of the drum the said drum being kept constantly rotating so as to gently
and equally turn over the leaf or other material or substance and expose all the
particles to the action of the hot blast.
And in order that my said Invention may be more clearly understood I have
hereunto appended a Sheet of explanatory Drawings on which Figure 1, is a side
elevation partly in section of the apparatus constituting the Invention, and
Figure 3, is a part plan and part horizontal section thereof and which consists of a
framing L, whereon is supported the drum M. The drum is composed of two
strong and preferably galvanized iron side plates connected by cross arms and
bolted to hollow bosses N, which work on or round centre bosses on the frames L.
Between the two side plates wire cloth or its equivalent of suitable mesh extends
round the drum and at a distance inwards from the circumference and concentric
with it another breadth of wire cloth is fitted. The annular space so enclosed is
partitioned off into compartments (preferably four) by wire cloth radial divisions O,
thus forming four quadrant boxes round the drum into and from which the tea
leaf, or other material is loosely filled and removed through wire cloth doors O¹, one
Buch door being provided in the circumference for every two compartments whilst a
single wire cloth door is provided in the inner side to afford access to the fan P,
hereinafter more particularly referred to. As indicated the material is so filled in
as not to quite fill the compartments, but to leave room for turning over as the
drum rotates

page_text: On one side of the drum M, a spur wheel Q, with its teeth at the inner side of
the rim is secured and geared with a pinion a, fixed on a stud carried in a sleeve b,
on the framing L. On the said stud a pulley c, is also secured so as to rotate the
drum by a crossed belt d, passed round the said pulley c, and round another
pulley e, on the main spindle R, of the machine and which may either be rotated
by hand or by a belt from a prime mover, passed round the pulley S, of the fast
and loose pulleys S, S¹.
The exhaust and blast fan P, situated at the interior of the drum M, has four
curved blades f, and at g, Figure 3, it has formed on it a short hollow or pipe boss
as indicated in dotted lines, in which is fixed a four bladed screw or auxiliary fan
which rapidly revolving together with the main fan draws the hot air from the
pipe J, connected to the top of the stove or to the top of a furnace burning coke
or charcoal and through which the air to be heated passes. The hot air so drawn
is thrown or forced by the blades f, of the main fan through the wire cloth inner
casing of the drum M, and thence through the tea leaves or other particles being
dried which particles are, during the treatment turned over by the slow rotation
of the drum the motion of which as indicated by the arrows is preferably in the
contrary direction to that of the fan P. The steam from the wet material rapidly.
escapes through the meshes of the wire cloth outer casing of the drum.
The fan P; is driven by a belt passed round the pulley U, keyed on the shaft R,
and round a flanged pulley h, keyed on the fan spindle k, which spindle is
preferably made of steel and rapidly revolves in a gun metal bearing i, at the cool
end where oil can be used for lubrication. The other or hot end of the spindle k,
has a novel bearing and revolves on a packing composed of first.an inside ring or
layer of pure asbestos rope and one or more inner rings or layers of compressed
plumbago or black lead placed inside a stuffing box j, cast on the pipe J, and which
box is furnished with a gland l. These materials asbestos and plumbago have great
lubricating properties and will not be burned away by any heat that may pass
through the pipe and when worn can be renewed in a few minutes. By the
employment of this packing at the bot end of the shaft k, the use of oil at that
bearing is obviated and any risk of smoke or fumes from burning oil getting at and
deteriorating the materials being treated is entirely prevented.
By the use of this Invention the out-turn of dried materials is much increased
and there is further much less risk of burning or scorching the materials than
when it is treated lying at rest on trays or travelling webs or on drying floors.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is,
The arrangement of apparatus for rapidly drying particles or short pieces
of materials or substances and wherein the material or substance is loosely
contained in one or more wire meshed boxes or compartments and submitted to
the action of hot air directly on the face of the particles which are held from
blowing away but are yet free to turn over in the said boxes or compartments so
as to expose fresh surfaces to the action of the blast substantially as described with
reference to the appended Drawings.