Improvements in Apparatus for Drying Tea Leaf.
Year: 1885

page_text: Improvements in Apparatus for Drying Tea Leaf.
We, WILLIAM HAWORTH, of 7 Lothbury, in the City of London, Merchant, and
JAMES COPELAND, of Pulteney Street, Glasgow, 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, that is
to say :-
Our said Invention comprises an improved combination of apparatus for drying
tea leaf together with various improved details; and apparatus made with our
improvements is represented on two accompanying sheets of explanatory drawings.
Figures 1 and 2, on sheet, 1, of the drawings are vertical and horizontal sections
of the part of the apparatus which is used for heating the air employed in drying
the tea leaf; and figures, 3, and 4, on sheet, 2, are longitudinal and transverse
vertical sections of the part of the apparatus in which the tea leaf is operated upon,
whilst figures, 5, and 6, are enlarged views showing the construction of endles
aprons by which the tea leaf is conveyed through the apparatus. In these
drawings the same reference numerals are used to mark the same or like parts
wherever they are repeated.
The air heating apparatus, shown in figures, 1, and 2, is constructed with an
ordinary fire grate, 11, from which a flue, 12, extends upwards in an inclined
direction, this flue communicating at its higher end, by ports, 13, with a chamber, 14,
in which there are a number of iron pipes, 15. These pipes, 15, and the chamber, 14,
are shown as being vertical, but they may be inclined or horizontal if preferred.
The pipes, 15, which are of an oblong form in cross section, as seen in figure, 2, are
fixed in upper and lower horizontal plates, 16, 17, which enclose spaces, 18, 19, at
the upper and lower ends of the chamber, 14. The air to be heated is made to
pass through the vertical pipes, 15, which are heated by the combustion products
from the fire place, 11, a fan or any suitable blowing apparatus, which is not
shown, being used to force the air through the apparatus, and causing it to enter
through an inlet, 20, into the upper space, 18, communicating with the upper ends
of the pipes, 15. After passing through the pipes, 15, the heated air proceeds from
the lower space, 19, by an outlet, 21, to the apparatus in which the tea leaf is
subjected to its action. The combustion products pass away from the chamber, 14,

page_text: by a flue, 22, at its lower end and on the opposite side to that in which the inlet
ports, 13, are formed, the flue, 22, communicating with a chimney, 23.
The tea leaf is operated upon in a chamber or casing, 24, (figures, 3, and 4,)
represented as constructed of sheet iron upon angle-iron framing, but which may
be constructed of wood if preferred. Within this casing, 24, there are several
endless aprons, 25, distended horizontally one above the other; and the alternate
aprons are moved in opposite directions as indicated by the arrows, and are
arranged so that the tea leaf which is placed on one end of the top apron is carried
along by it and by each lower apron in succession, the end of each apron receiving
the tea leaf from the apron next above it projecting beyond the latter to catch the
tea leaf falling therefrom, whilst inclined plates, 26, also serve to guide the tea leaf
from one apron down to the next lower one. The tea leaf to be dried is placed in
an entering hopper, 27, under which the top apron, 25, extends; and in the lower
part of this bopper at the outer side there is a flap, 28, of vulcanised rubber or
other suitable flexible material to prevent the hot air from having a too free egress
out of the casing. At the inner side of the hopper, 27, there is another flexible
flap, 29, which whilst preventing too free egress of the hot air also serves to spread
the tea leaf uniformly upon the apron and to regulate the thickness of the layer of
tea leaf which the apron carries in from the hopper. This inner flap, 29, may be
made adjustable so that the thickness of the layer of tea leaf may be varied in
different cases if required. Above each apron, 25, near the end upon which the
tea leaf falls, there is an adjustable flexible flap, 30, under which the apron carries
the tea leaf and which spreads and equalises the thickness of the layer of tea leaf.
From the lowest apron the tea leaf finally falls down a discharge duct, 31, into a
box or receptacle, 32, in which it is removed from the apparatus. A number of
doors, 33, are fitted to the sides of the casing, 24, to allow of the tea leaf being
examined at various stages of its progress through the apparatus. The heated air
from the heating apparatus shown in figures, 1, and 2, and hereinbefore described,
passes from the outlet, 21, by a duct or pipe or by two or more such ducts, 34, into
the casing, 24. In the casing, 24, the heated air proceeds to some extent in
successive horizontal streams moving in directions opposite to those in which the
tea leaf is conveyed by the aprons, 25. The aprons, 25, are, however, permeable
being made with wire gauze of a coarse mesh and a large portion of the heated air
passes up through the aprons and through the tea leaf lying upon the aprons. The
air finally passes off by an outlet, 35, at the top of the casing, 24, this outlet being
provided with a balanced door, 36, the opening of which can be adjusted.
The endless aprons, 25, are of an improved construction each consisting of a
series of transverse strips, 37, (figure, 5,) of wire gauze which are sewn or connected
together by wire spirals which also pass round transverse supporting rods, 38. At
the two sides of each apron the rods, 38, are connected by links, 39, the ends of the
rods acting as joint pins connecting the links to each other. The links, 39, pass
round square pulleys, 40, fixed on transverse horizontal shafts, 41, 42, which serve
for distending and moving the endless aprons, 25. The shafts, 41, at one end of
the casing, 24, extend through bearings to the outside of the casing, and have
spurwheels, 43, (indicated by dotted circles in figure, 3,) fixed on them externally.
The lowest spurwheel, 43, is driven by a worm, 44, driven by any convenient
prime mover, and the motion is transmitted from one spurwheel to the next, the
spurwheels being in gear with each other and their shafts, 41, moving the endless
aprons, 25, by means of the square pulleys, 40.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is
1. The combination of parts forming the improved tea leaf drying apparatus
batantially on hominhawn doannikad

page_text: 2.-The arranging or combining together of the parts of apparatus for heating
air to be used for drying tea leaf substantially in the improved manner bereinbefore
described with reference to figures, 1, and 2, of the accompanying drawings.
8. The improved construction of the endless aprons for conveying the tea leaf
through the drying apparatus, substantially as hereinbefore described.
4. The application of the flexible flaps (29, 30) for spreading the tea leaf
and equalising its thickness on the endless aprons, substantially as hereinbefore
described.