An Apparatus for Drying Tea or similar Substances.
Year: 1889

page_text: Date of Application, 14th June, 1889
Complete Specification Left, 14th Mar., 1890-Accepted, 19th Apr., 1890
PROVISIONAL SPECIFICATION.
[Communicated from abroad by JOSEPH EDWARD LYNDALL, of Sylhet, India,
Engineer.]
An Apparatus for Drying Tea or similar Substances.
:
I DANIEL SMITH SINCLAIR of 54 Gordon Street Glasgow in the county of Lanark,
Engineer, do hereby declare the nature of this invention to be as follows:-
A form of apparatus for the drying of tea or similar substances by means of air
heated by contact with hot metal surfaces.
In this apparatus there are a stove-part of a combustion chamber-a heating
chamber-a smoke box, and a drying chamber, successively above one another.
The furnace may be arranged to burn wood, coal, petroleum, or other fuel and the
products of combustion pass from the stove to the combustion or mixing chamber
surrounding the stove on 3 sides; then through a set of vertical pipes in the heating
chamber and into the smoke box. Thence they are led away by a chimney passing
through the drying chamber.
The air used for drying enters at the lower part of the heating chamber and
passes around the smoke pipes to the drying chamber by a bye pass on the smoke-box.
The heated air is thus kept entirely separate from the smoke etc.
In the drying chamber the hot air is distributed by a series of baffle-boards which
serve also to carry away the dust and fine tea falling from the trays above.
The trays on which the tea to be dried or fired is laid, are placed in one or more
layers towards the top of the drying chamber and when there is more than one layer
the construction is such that each layer is supplied with a portion of fresh air.
A fan may be used to draw the air more rapidly or in larger volumes, through the
apparatus but it is not necessary for efficient working.
Dated the Thirteenth day of June 1889.
D. S. SINCLAIR,.
Applicant.
COMPLETE SPECIFICATION.
An Apparatus for Drying Tea or similar Substances.
I DANIEL SMITH SINCLAIR of 54 Gordon Street Glasgow in the county of Lanark,
Engineer, (communicated from abroad), 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 :-
In order to better explain the construction and working of this apparatus as
described in the Provisional Specification relative hereto 1 have prepared the annexed
drawing
COMPLETE SPECIFICATION.
An Apparatus for Drying Tea or similar Substances.
I DANIEL SMITH SINCLAIR of 54 Gordon Street Glasgow in the county of Lanark,
Engineer, (communicated from abroad), 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 :—
In order to better explain the construction and working of this apparatus as
described in the Provisional Specification relative hereto 1 have prepared the annexed
drawings
Fig. 1 is a front view of the apparatus or Dryer as I shall hereinafter call it―
Fig. 2 is a cross section and
Fig. 3 a longitudinal section at the centre.
In these Figures the same letters indicate the same parts.
The general appearance of the Dryer will be manifest from these drawings and
any parts not specifically mentioned are to be considered as being constructed on
well known lines and of materials such as would usually be employed for similar
purposes.
In the following description of this invention I have more particularly in view the
operation of firing tea in the course of manufacture after the methods at present in

page_text: use but this is without prejudice to the apparatus as applicable to similar purposes
or to certain parts of it claimed as novel to other processes.
Fig. 1 shows the furnace front A with the stoking door and ashpit below. B–B is
the lower part of the Dryer here shown built of brick, forming, the outer wall of the
combustion chamber G and supporting the upper part of the apparatus. (-C is the
heating-chamber formed of metal plates; D-D is the smoke-box and E-E, the drying-
chamber.
In Figs. 2 and 3 the internal construction is seen. F F are flues through
which the products of combustion in the furnace pass to the combustion-chamber G.
Instead of passing directly to the heating-chamber the burnt gases are in this
combustion-chamber allowed more thoroughly to mix with the cooler air which
has been merely drawn through the furnace by the up-draught. Thus is produced
a volume of hot gas practically of equal temperature throughout and overheating of
portions of the Dryer avoided. A reduction of temperature in G may be obtained
by partially opening the regulator doors R.
His a tube-plate of fire-brick or other refractory material into which the lower
ends of the tubes I project a short distance. As will easily be understood this forms
an efficient protection to the ends of these tubes which soon become burnt when
exposed to the direct action of the fire. The holes for the tube-ends are shown
parallel through the brick but I also make them of smaller diameter on the underside
as in Fig. 4 so that the tube-ends are still better protected from the rush of burnt
gases.
The products of combustion pass into the smoke-box D and are discharged by the
chimney L.
The air to be heated and used for drying enters at the regulator doors M, passes
to the further side of the chamber C, thence upwards through apertures in the baffle-
plate N and reaches the drying-chamber by a by-pass to the smoke-box as shown.
The lower part of the drying-chamber is fitted with a series of shelving baffle-plates
which serve to equally distribute the heated air and to allow the tea-dust or
'dhoolgoorie' dropping from the trays above to be discharged through apertures as
at O into a suitable receptacle outside the Dryer.
The firing trays are run into the Dryer on angle-iron supports and between these
and the wall of the drying chamber I provide a means of supplying each tray with
a portion of fresh air in addition to that passing through the lower trays. The
supports referred to are placed at some distance from the side of the chamber and
have, in the case of the intermediate ones, a plate projecting so as to intercept a
portion of the air freely passing up at the side and cause it to pass as shown by the
direction-arrows in the drawing. Between the top tray runner and the wall the space
is completely bridged by such a plate and prevents any air from escaping except
through the top tray. The moist air then discharges into the atmosphere or may be.
led away for other use.
In the furnace shown natural draught is used both for promoting combustion and
for circulating the drying agent, the hot air, but a fan suitably arranged may be used
to augment or regulate the volume of air passing through.
P, P are the cleaning doors for the smoke-box and Q, Q those for the combustion-
chamber.
I may also without prejudice to anything herein contained use 'baffle-plates con-
structed after any well known method and placed in the combustion chamber to
regulate the heating of the tubes.
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 :-
:
-
I. An apparatus for drying tea having the several parts substantially as described
herein and shown on the accompanying drawings.

page_text: 11. In an apparatus for drying tea or similar substances the arrangement and use
of a combustion chamber substantially as and for the purpose described.
III. In apparatus making use of heating-tubes such as those shown; the tube-
plate of firebrick for the protection of the tube-ends.
IV. In apparatus for drying by hot air the use of plates arranged as shown and
described to subdivide and apportion the drying agent.
Dated this Thirteenth day of March 1890.
D. S. SINCLAIR