Improvements in Apparatus for Drying Tea and other Substances.
Year: 1896

page_text: Date of Application, 10th June, 1896
Complete Specification Left, 21st Sept., 1896-Accepted, 24th Oct., 1895
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Drying Tea and other Substances.
We, WILLIAM ALFRED GIBBS, of Gilwell Park, Chingford, Gentleman, and
GILBERT WILLIAM SUTTON, of Rothmans, Great Baddow, Chelmsford, Civil
Engineer, both in the County of Essex, do hereby declare the nature of this
invention to be as follows:-
Our invention relates to apparatus for drying tea and other substances in vacuo,
and has for its chief object to provide means whereby the introduction and removal
of the substances into and from the drying chamber may be effected without
destroying the vacuum and so interfering with the drying operation.
In carrying out our invention we arrange in the drying chamber a series of
shelves in such a manner that the material to be treated will be caused to pass from
one shelf to another, for instance, pivoted inclined shelves may be employed, the
said shelves being shaken by any suitable arrangement of mechanism in order to
cause the material lying upon them to gravitate towards the lower ends thereof, or
the said shelves may be in the form of endless travelling platforms. Beneath
these shelves and in some cases also above them we arrange coils through which
steam or other heating medium can be caused to pass.
For introducing the undried material and removing it when dried, we provide
inlet and discharge chambers at the upper and lower ends respectively of the drying
chamber, which inlet and discharge chambers have arranged in conjunction with
them valves or other closing devices so that communication between the said
chambers and the drying chamber cannot be effected until communication between
the said chambers and the atmosphere has been cut off and vice versú.
Where the continuous operation of the apparatus is not essential the material to
be dried may be placed upon a series of trays which can be introduced into the
drying chamber between heating coils, openings being formed in the wall of the
said chamber for allowing of the introduction and removal of the said trays; these
openings are closed by independent covers which lie against inclined seats so that
the weight of the covers themselves assists in maintaining tight joints for preventing
the admission of air.
Improvements in Apparatus for Drying Tea and other Substances.
We, WILLIAM ALFRED GIBBS, of Gilwell Park, Chingford, Gentleman, and
GILBERT WILLIAM SUTTON, of Rothmans, Great Baddow; Chelmsford, Civil
Engineer, both in the County of Essex, 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:-
Our invention relates to apparatus for drying tea and other substances in vacuo

page_text: and has for its chief object to provide means whereby the introduction into and
removal of the substances from the drying chamber may be effected without
destroying the vacuum and so interfering with the drying operation.
In carrying out our invention we arrange in the drying chamber a series of
shelves in such a manner that the material to be treated will be caused to pass
from one shelf to another, for instance, pivoted inclined shelves may be employed,
the said shelves being shaken by any suitable arrangement of mechanism in order
to cause the material lying upon them to gravitate towards the lower ends thereof,
or the said shelves may be in the form of endless travelling platforms. Beneath
these shelves and in some cases also above them we arrange coils through which
steam or other heating medium can be caused to pass.
For introducing the undried material and removing it when dried, we provide
inlet and discharge chambers, at the upper and lower ends respectively of the
drying chamber, which inlet and discharge chambers have arranged in conjunction
with them valves or other closing devices so that communication between the said
chambers and the drying chamber cannot be effected until communication between
the said chambers and the atmosphere has been cut off and vice versa.
Where the continuous operation of the apparatus is not essential the material to
be dried may be placed upon a series of trays which can be introduced into the
drying chamber between heating coils, openings being formed in the wall of the
said chamber for allowing of the introduction and removal of the said trays.
These openings are closed by independent covers which lie against inclined seats
so that the weight of the covers themselves assists in maintaining tight joints for
preventing the admission of air.
To enable our invention to be fully understood we will describe the same with
reference to the accompanying drawings, in which :-
Figure 1 is a sectional elevation of a tea-dryer having a series of pivoted shelves:
and,
Figure 2 is a sectional view looking in the direction of the arrow, Figure 1:
Figure 3 is a section on the line 3-3, Figure 2:
Figure 4 is a sectional elevation of the apparatus wherein sliding shelves are
employed:
Figure 5 is a sectional side elevation of the said apparatus; and,
Figure 6 is a horizontal section on the line 6-6, Figure 5.
Similar reference letters indicate corresponding parts throughout the drawings.
In the continuously working apparatus shewn in Figures 1 to 3 a is the drying
chamber having the inlet b for the substance to be dried and an outlet e for the
discharge of the substance when dried. d is a flanged opening for connection with
the vacuum producing apparatus, e, e are the pivoted inclined shelves all of which
with the exception of the upper shelf are pivoted at e and which are designed to
be knocked or shaken in order to cause the material lying upon them to gravitate
from one shelf to the other through the entire apparatus.
As shewn in the drawings, each of the shelves except the uppermost shelf is
provided with extensions upon which the superposed shelf is supported and
beneath the lowermost shelf is a rod g operated by a snail or cam so shaped that
at each revolution the shelves are raised and then suddenly allowed to drop.
In cases where the material to be dried is of a somewhat sticky nature and
would therefore tend to more or less stick or adhere to the upper shelf until
partially dried, we provide for mechanically moving the said substance and for
this purpose we have shewn in connection with the uppermost shelf two bars o
stirrers h, carried by sprocket chains i, i running over sprocket wheels
on two shafts j, j the former of which is carried in bearings upon the
shelf whilst the latter serves as a pivot upon which the upper shelf oscillates
and which extends through a stuffing-box in the side of the chamber and i
provided on its outer end with a hand-wheel k as shewn in Figure 2. So long
as the material will gravitate along the upper shelf under the shaking action
these bars or stirrers h, h remain in the position shewn in Figure 1. In case it i

page_text: necessary, however, to move the material upon the said shelf the said hand-wheel
is turned in order to move the chains i, i to bring the said bars h, h into contact
with the material upon the said shelf and move it along in the desired manner.
In Figure 1 we have represented the stirrers as being arranged in connection
with the upper shelf only but it will be obvious that similar mechanism can be
arranged in conjunction with each shelf or with as many of the shelves as may be
desired.
1, are heating coils which are arranged beneath the several shelves. If desired
similar coils may be arranged above the shelves where the scraping or stirring
arrangement is not used. The several coils are connected with common flow and
return pipes m, m as clearly shewn in Figure 3.
w is a hopper into which the material to be dried is placed. In order to prevent
the vacuum from being destroyed when any material passes from the hopper into
the drying chamber, we provide the said hopper with two valves n', n2 which are
so arranged that when one is closed the other is open and vice versa. As shewn in
the drawings each of these valves is provided with a pair of racks operated by
mutilated pinions a, a on a shaft a carrying a hand-wheel n which, when turned
in the direction of the arrow Figure 1, first close the valve n2 and then open the
valve n so that any material lying upon the said valve n' will fall on to the valve n².
When the mutilated pinions are turned in the reverse direction, the valve n' is
first closed and then the valve n is opened so that the material lying upon it falls
on to the uppermost shelf in the apparatus, whence it gravitates along the several
shelves to the discharge outlet c.
o is a chamber provided with an air-tight cover o' arranged in connection with
the discharge outlet and adapted to contain a basket o into which the dried
substance will fall; this basket may be made of such size that it will receive
the material being dried for some time without the necessity for removing it.
For the purpose of shutting off communication between the chambers a and o
during the time that the basket o' is being removed, we provide the valve p which
is operated by the pinion pl. When the valve p is closed the cover of is removed,
a cock q on the chamber o being first opened to admit air into the said chamber.
In the arrangement of our invention shewn in Figures 4, 5 and 6, r, r indicate
the removable trays which slide on suitable guides above heating coils, which
latter are advantageously arranged as indicated by the dotted lines in Figure 6.
3, are the doors which permit of the introduction and removal of the said trays
into and from the chamber, the said doors being pivoted at s', s so as to lie against
inclined seats formed around the openings u through which the trays r, rare
introduced. In each seat t around the opening u is arranged a packing-ring of
india-rubber or other suitable material against which the doors will lie to form a
hermetic joint.
pin
We sometimes find it advantageous to provide each of the doors a, s with a
or projection to, which pins or projections are inserted in holes in a common rod
so that all the said doors can be opened and closed simultaneously. In the
drawings the upper end of the rod wl is represented as being connected to one arm
of a bell-crank lever w³, the other arm of which is connected by a link w³ to a
hand-lever in such a manner that when the said lever is moved the doors will be
operated.
y is an air-exhausting pump which is shewn as arranged upon the top of the
chamber; it will be obvious, however, that it may be arranged in any other suitable
position.
In practice we find it advantageous to connect the cock y', by means of which
steam for working the exhausting pump is admitted to the steam cylinder, to the
lever so that when the said lever is moved to open the doors s, s the cock y' will
be operated to shut off the steam and stop the pump. z is a valve also connected
with the lever to admit air into the chamber for destroying vacuum existing
therein so as to permit of opening the doors s, s.
The arrangement of the link to, between the bell-crank lever w² and the lever,

page_text: permits of a movement being imparted to the said valve z before any movement of
the doors commences.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In apparatus for drying tea and other substances in vacuo, the combination of
a series of pivoted inclined shelves arranged to be vibrated or shaken so as to cauise
the substances lying upon them to gravitate, and means for introducing the substance
to be dried into the drying chamber and removing it therefrom without destroying
the vacuum substantially as described.
2. In apparatus for drying tea and other substances in vacuo, the combination
with the closed drying chamber, of a series of superposed pivoted shelves adapted
to be vibrated or shaken, a series of heating coils arranged beneath the said shelves
and means for stirring or moving the substances lying upon the said shelves, a
double valved hopper into which the substances to be dried are introduced and
from which they can fall into the drying chamber without destroying the vacuum
and a discharging chamber into which the dried substances will pass, substantially
as described.
3. In apparatus for drying tea and other substances in vacuo, and of the kind
wherein a series of superposed trays arranged in conjunction with heating coils is
employed, the arrangement of doors hanging against inclined seats and provided
with means for preventing the entrance of air when the said doors are closed,
substantially as described.
4. In apparatus for drying tea and other substances in vacuo and of the kind
wherein a series of removable trays is employed, the combination with the drying
chamber, having doors for closing the openings through which the trays are
introduced, of means for operating all the said doors simultaneously, and at the
same time operating the regulating valve of the vacuum producing apparatus and
also a valve for controlling communication between the interior and exterior of the
chamber, substantially as described.
5. The improved apparatus for drying tea and other substances in vacuo
constructed and arranged substantially in the manner hereinbefore described and
illustrated in Figures 1 to 3 and Figures 4 to 6 of the accompanying drawings.
Dated the 21st day of September 1896.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.