An Apparatus for Simultaneously Cooling and Partially Drying Tea Leaf during Part of the Process of its being Manufactured into Tea.
Year: 1891

page_text: Date of Application, 21st Apr., 1891
Complete Specification Left, 21st Jan., 1892-Accepted, 27th Feb., 1892
PROVISIONAL SPECIFICATION.
An Apparatus for Simultaneously Cooling and Partially Drying
Tea Leaf during Part of the Process of its being Manufactured
into Tea.
I, SAMUEL CLELAND DAVIDSON of Sirocco Works, Belfast, Ireland, Merchant,
do hereby declare the nature of this invention to be as follows:-
This invention consists of an apparatus for simultaneously cooling and partially
drying tea, leaf during that part or stage of its manufacture into tea which inter-
venes between the rolling process and the complete drying of the leaf with highly
heated air or other strong heat. By this simultaneous cooling and partial drying
of the leaf it undergoes at a sufficiently cool temperature what is usually described
as the process of fermentation, while it becomes at the same time sufficiently dry
to allow of its being then subjected to complete drying by means of strong heat
without this heat causing that deterioration of the quality of the product to which
it is liable when subjected to strong heat in the very moist condition in which the
ordinary fermentation process leaves it.
My apparatus is composed of a box, chamber, or apartment with an open top
into which slides are fitted to carry one or more sieves or perforated trays on which
a layer of rolled tea leaf of suitable depth can be spread; these trays can be made
of wire netting, coarse cloth or other material through which the air will easily
pass. The lower part of the box is so connected to a fan or other air exhausting
appliance that a strong current of air can be drawn therefrom and down through
the material on the trays. Or this apparatus may be inverted so that the trays
slide in below and the air be exhausted from above them, thus causing the air
current to pass in an upward direction through the material thereon. In either of
these arrangements the draft can as an alternative method be produced by a
pressure blast from below or above the trays as the case may be and when more
than one tray or sieve are employed they may either be arranged as a column one
above the other or in one or more rows side by side or superimposed. A. suitable
valve or valves for cutting off and opening or for regulating or controlling the air
current or blast are fitted where required, and a perforated plate may be placed
above or below each tray to equalize the current of air through the material on
same.
In employing my apparatus for simultaneously cooling and partially drying tea
leaf as aforesaid I take the leaf immediately or soon after it comes out of the
rolling machine (at which time owing to the rolling process its temperature is
usually increased to about 10 or 15 degrees above the ordinary atmospheric
temperature at which it was put into the rolling machine) and I spread it in layers
a few inches thick on the trays, and I then draw or force through it a current of
more or less desiccated air at the ordinary atmospheric temperature or a few
degrees above it until a considerable portion of the moisture of the leaf has been
carried off thereby. The evaporation thus produced causes a reduction in the
temperature of the leaf to very considerably below that of the atmosphere, and this
effect is maintained so long as evaporation is taking place. When the surfaces of
the leaf are becoming dryish the leaf may again be subjected to the rolling process,
after which it should be again subjected to the forced draught of cool air in my
apparatus; this operation can be repeated as many times as may be found desirable
and when the juices are becoming sticky or gummy the leaf can then with advantage
be completely dried in the usual way with highly heated air.
If the atmosphere be very damp and laden with moisture the air before being
drawn.or formed through the material on the trays may be artificially dried by

page_text: raising its temperature to 10 or 15 degrees above that of the outside temperature
by drawing it over heated pipes or by employing an air heating stove or other
means of heating it.
· Dated this 21st day of Anril 1891
J. C. MEWBURN,
55 and 56, Chancery Lane, London, Patent Agent.
COMPLETE SPECIFICATION.
An Apparatus for Simultaneously Cooling and Partially Drying
Tea Leaf during Part of the Process of its being Manufactured
into Tea.
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:-
This invention consists of an apparatus for simultaneously cooling and partially
drying tea leaf during that part or stage of its manufacture into tea which intervenes
between the rolling process and the complete drying of the leaf with highly heated
air or other strong heat. By this simultaneous cooling and partially drying of the
leaf it undergoes at a sufficiently cool temperature what is usually described as the
process of fermentation while it becomes at the same time sufficiently dry to allow
of its being then subjected to complete drying by means of strong heat without this
heat causing that deterioration of the quality of the product to which it is liable
when subjected to strong heat in the very moist condition in which the ordinary
fermentation process leaves it.
My apparatus is composed of a box, chamber or apartment with an open top into
which slides are fitted to carry one or more sieves or perforated trays on which a
layer of rolled tea leaf of suitable depth can be spread; these trays can be made of
wire netting, coarse cloth or other material through which the air will easily pass.
The lower part of the box is so connected to a fan or other air exhausting appliance
that a strong current of air can be drawn therefrom and down through the material
on the trays. Or this apparatus may be inverted so that the trays slide in below
and the air be exhausted from above them, thus causing the air current to pass in
an upward direction through the material thereon. In either of these arrangements
the draft can as an alternative method be produced by a pressure blast from below
or above the trays as the case may be and when more than one tray or sieve are
employed they may either be arranged as a column one above the other or in one
or more rows side by side or superimposed. A suitable valve or valves for cutting
off and opening or for regulating or controlling the air current or blast are fitted
where required and a perforated plate may be placed above or below each tray to
equalize the current of air through the material on same.
In employing my apparatus for simultaneously cooling and partially drying tea
leaf as aforesaid I take the leaf immediately or soon after it comes out of the rolling
machine (at which time owing to the rolling process its temperature is usually
increased to about 10 or 15 degrees above the ordinary atmospheric temperature
at which it was put into the rolling machine) and I spread it in layers a few inches
thick on the trays, and I then draw or force through it a current of more or less
desiccated air at the ordinary atmospheric temperature or a few degrees above it
until a considerable portion of the moisture of the leaf has been carried off
thereby. The evaporation thus produced causes a reduction in the temperature
of the leaf to very considerably below that of the atmosphere, and this
effect is maintained so long as evaporation is taking place. When the surfaces-of
the leaf are becoming dryish the leaf may again be subjected to the rolling process
after which it should again be subjected to the forced draught of cool air in my
apparatus; this operation can be repeated as many times as may be found desirable

page_text: and when the juices are becoming sticky or gummy the leaf can then with advantage
be completely dried in the usual way with highly heated air.
If the atmosphere be very damp and laden with moisture the air before being
drawn or forced through the material on the trays may be artificially dried by
raising its temperature to 10 or 15 degrees above that of the outside temperature
by drawing it over heated pipes or by employing an air heating stove or other
means of heating it.
The accompanying drawings illustrate the construction of the apparatus.
Figure 1 is a cross-section of the apparatus arranged with one tray and an air
chamber or box below it, a pipe being connected thereto which is led to any air
exhausting or pressure blowing appliance.
Figure 2 is a plan of the apparatus shown in Figure 1.
Figure 3 shows a cross section of the apparatus arranged in an inverted form, the
air chamber being above the tray.
Figure 4 shows a similar arrangement to Figure 3 the pipe connection of the air
chamber being fitted with a valve and a perforated plate is inserted above the tray
to equalize the current of air through the material on same.
Figures 5, 6 and 7 show in longitudinal section, cross section and plan respectively
an arrangement of the complete apparatus in which a single tier of trays is employed
and the air chambers are fitted with perforated plates and valves to cut off or open
the connection with a powerful exhaust fan, this being the design which is preferably
employed.
Figure 8 is a longitudinal section of a similar apparatus to that shown in
Figures 5, 6 and 7 when fitted with two superimposed rows of trays.
The same letters of reference indicate the corresponding parts of the apparatus
in the several figures and are as follows :-
A. Air chamber or box.
J. C. MEWBURN,
55 and 56, Chancery Lane, London, Chartered Patent Agent.