Improvements in Apparatus for Drying Tea or other substances.
Year: 1892

page_text: Date of Application, 2nd Feb., 1892
Complete Specification Left, 24th Nov., 1892-Accepted, 31st Dec., 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Drying Tea or other substances.
I, SAMUEL CLELAND DAVIDSON of Sirocco Works, Belfast, Ireland Merchant,
do hereby declare the nature of this invention to be as follows:-
The invention has reference to apparatus for drying tea or other substances in
which the substance to be dried is exposed on perforated plates or trays to a current
of heated air passed through the plates or trays which are moved forward and
backward in a drying chamber or box between and by means of endless travelling
bands or chains passing round two or more returning wheels, and the trays or plates
are so adjusted between these bands that the edges of the trays in one form of the
apparatus overlap one another and in another form as hereinafter described touch
at the edges.
The object of the invention is to utilize as a drying surface each horizontal
stretch of an endless web consisting of flat perforated plates or woven wire trays
which have their edges overlapping or alternatively of trough shaped trays the edges
of which touch one another, the Hat plates or trays or trough shaped trays being
carried on pivots between endless bands or chains passing round two or more
returning wheels as a continuous web, and the material which is being dried on the
trays or troughs being automatically delivered down from stretch to stretch as the
web moves forward in such a way that the material gets turned and respread at
each transfer.
Hitherto the utilization of the under or returning horizontal stretch of endless
bands or trays in combination with the dropping of the material from the upper to
the lower stretch of trays has only been effected and used in connection with endless
bands in which the trays do not overlap at the edges, but are pivoted at one edge
so that they can turn or drop clear of each other and which pass round a single
pair of returning wheels, i.e. one at either end of the bands, and the arrangements
hitherto employed for working same would not work if applied to overlapping
trays, as in this case the overlap would be wrong side up on the returning or lower
stretch of the trays, and the trays would not drop at the end of this return
journey, and further, this utilization of the under or returning horizontal stretch
has not been attempted with hanging troughs pivoted to endless bands. It is a
great practical benefit when using trays which are pivoted at one side of their
centre of gravity to use overlapping trays as the overlap prevents the material
dropping through between the trays, and if the trays get askew to one another
from elongation of either of the conveying chains the overlapping edges
accommodate themselves by slipping further or less into overlap without fouling
one another or sticking, whereas with flat trays the edges of which do not overlap
the edges must be so closely butted to one another to prevent material falling
between them prematurely that a slight elongation of either chain or any material
getting jammed in between the edges will cause them to stick and otherwise
derange the working of the bands so as to stop if not break the trays themselves,
and owing to this liability to derangement machines of this class have not hitherto
been of much practical utility.
My present invention as it renders flat trays which overlap efficiently workable
and without the drawbacks pertaining to those which do not overlap, is therefore
likely to be of much public utility.
My invention consists in constructing the apparatus with endless bands or chains
carrying between them perforated trays which when in their horizontal position
overlap one another so that the leading edge of each tray is on top of the trailing
edge of the tray preceding it, and which trays are connected to the carrying bands,

page_text: preferably at the points of junction between the links of the bands by pivots which
project into sockets in the end frames of the tray and are at one side of its centre
of gravity so that the tray will hang vertically when not supported. These trays
as they travel with the endless bands in their upper or forward movement are
supported by horizontal rails or bars until they approach the end of this movement
when the rails or bars terminate and the trays as they successively pass beyond the
rails drop or turn on their pivots and consequently discharge their contents which
then fall on to the trays which are making the return movement along under rails.
As the trays and endless chains are passing downwards over the returning wheels
at the end of the upper or forward movement each tray is acted upon by means of
a fixed bar or other suitable obstruction, so that its lower edge is projected over the
upper edge of the tray next in front of it, whereby the overlap is reversed. This
reversal of the overlap without which overlapping trays would not work is an
important part of this invention. By the reversal the trays when they re-assume
the horizontal position and commence the under or return movement along the
under rails have each their leading edge again on the upper side of the trailing
edge of the preceding tray same as on their forward or upper movement on the top
rails. Consequently when they reach the end of this return journey where their
supporting rails terminate in same way as at the end of the forward movement on
the top rails, the trays again drop or turn on their pivots, and the contents fall on
to the upper surface of another similarly constructed endless band of trays next
below, or in the case of the last band to the outlet or discharge part of the
apparatus. Immediately after thus discharging its load of material each tray is
then so guided that its upper edge is projected past the lower edge of the tray next
in front, so that in passing upwards round the returning wheels at this end of the
apparatus the overlap of the tray is again so reversed that on the trays being
drawn on to the upper rails to recommence their forward movement in the
horizontal position the leading edge of each tray again overlaps the one preceding
it in the sam: y as at the outset of their movement.
The above description refers to webs which pass round only a single pair of
returning wheels, i.e. one at each end of the stretch, but where the web is carried
round more than two returning wheels it only means that so long as the trays are
descending to a lower stretch of the web the same arrangement as above described
for bringing them from first or top rails to second lower rails is again applied to
bring them from the second to the third and from the third to the fourth, and then
when they have again to ascend to the top rail or starting point the arrangement
already described for adjusting the trays in their upward movement is again
applied.
When utilizing this form of apparatus to work with the trough shaped trays
which are so pivoted as to always hang swing-like so that their drying surface
keeps horizontal, guiding rails are unnecessary for the trays to travel along, con-
sequently they are entirely supported by their pivots. This form of tray may be
used in same way as above described for the flat trays, that is with two or more
returning wheels, but when the trays reach the end of their first forward movement
fixed projecting pins engage hooks or other suitable projections on the ends of the
trays so that in the onward movement of same the trays are turned over by the
pins, and on passing these pins they again fall into their horizontal position and
descend round the returning wheels and move along the next under horizontal
stretch with their edges again touching and in this position receive the material
which is tilted out of the trays which are travelling along the upper stretch. On
reaching the end of the lower stretch these trays are again similarly tilted and may
be carried downwards and round another pair of returning wheels, or carried up to
the starting point again as may be desirable.
The top endless band may be supplied by any suitable feeding or spreading
arrangement with the tea or other substance to be dried. In the case of tea it is
preferred to adopt a feed hopper and rotating cruciform bars as described in my
Specification No. 14824 of 1890.

page_text: The outlet for the dried tea or other substance may also be of any suitable kind
For tea the
and will vary according to the particular material operated on.
preferred arrangement consists of a revolving drum with radial divisions which fit
a cylindrical part of the outlet. The tea drops into the drum and the divisions
carry it round and drop it out at the bottom without letting air pass either
in or out.
The air for drying the tea or other material may be heated or cold and be
driven vertically through the travelling trays and the material thereon either
downwards or upwards but preferably downwards so as not to disturb the substance
on the trays while using a strong current which may be created either by an
exhausting or a blowing apparatus as may be preferred.
Dated this 2nd day of February 1892.
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Drying Tea or other substances.
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 :-
The invention has reference to apparatus for drying tea or other substances in
which the substance to be dried is exposed on perforated plates or trays to a current
of heated air passed through the plates or trays which are moved forward and
backward in a drying chamber or box between and by means of endless travelling
bands or chains passing round two or more returning wheels and the trays or plates
are so adjusted between these bands that the edges of the trays, in one form of the
apparatus, overlap one another, and in another form as hereinafter described, touch
or overlap at the edges.
The object of the invention is to utilize as a drying surface each horizontal
stretch of an endless web consisting of flat perforated plates or woven wire trays
which have their edges overlapping or alternatively of trough-shaped trays the
edges of which either touch or overlap one another, the flat plates or trays or
trough-shaped trays being carried on pivots between endless bands or chains passing
round two or more returning wheels as a continuous web, and the material which is
being dried on the trays or troughs being automatically delivered down from
stretch to stretch as the web moves forward by the tilting or overturning of the
trays consecutively as they reach or approach the end of each stretch in such a
way that the material gets turned and respread at each transfer, and fresh surfaces
of it are thereby presented to the action of the current of air which is being drawn
through it for the purpose of drying it, and its drying is thus more evenly and
rapidly effected than if the material were not turned or tossed in its passage through
the drying chamber.
Hitherto the utilization of the under or returning horizontal stretch of endless
bands or trays of a drying apparatus as drying surfaces, in combination with the
dropping of the material from the upper to the lower stretch of trays, has only been
effected and used in connection with endless conveying or carrying bands or chains
which pass round a single pair of returning wheels, i.e. one at either end of said
bands, and in which the edge or other part of the perforated trays is in a direct
line between and forms as it were a continuation of the pivots on which they are
suspended between said endless bands or chains, and in which these trays when
lying horizontally do not overlap at their edges and are therefore able to turn or
drop clear of each other freely and the arrangements hitherto employed for working
these trays would not work if they overlapped at their edges, as in this case the
overlap would be wrong side up on the returning or lower stretch of the trays, and

page_text: the trays would not drop at the end of this return journey; and further, this
utilization of the under or returning horizontal stretches of perforated trays or
troughs which hang swing-like below a direct line between the pivots on which
they are suspended between endless conveying or carrying bands, has not been
attempted in combination with the dropping of the material from the upper to the
lower stretches so as to toss or turn it to hasten and facilitate its drying. It is a
great practical benefit to be able to use either of the above referred to types of
trays with their edges overlapping as the overlap prevents the material dropping
through between the trays, and if the trays get askew to one another from
elongation of either of the conveying chains, the overlapping edges accommodate
themselves by slipping further or less into overlap, without fouling one another or
sticking, whereas with trays the edges of which do not overlap, the edges must be
so closely butted to one another to prevent material falling between them
prematurely that a slight elongation of either chain or any material getting jammed
in between the edges will cause them to stick and otherwise so derange their
working as to perhaps stop or damage them.
As one part of the present invention renders the first above mentioned type of
trays (hereinafter referred to as the "flat trays") the edges of which overlap one
another efficiently workable in combination with the dropping of the material from
the upper to the lower lines and respreading of same, and without the drawbacks
pertaining to flat trays which do not overlap, and as the other part renders the
second above mentioned type of trays or troughs (hereinafter referred to as the
swinging trays") efficiently workable with their edges either touching or over-
lapping in combination with the dropping or tossing of the material from the upper
to the lower stretches to hasten and facilitate its more even drying, the invention
affords great advantage.
One part of this invention consists in constructing drying apparatus with endless
conveying chains or bands which pass round returning wheels fitted with sprockets
or other suitable appliances for holding the chains in position on the wheels while
passing round same, and which chains carry between them flat perforated trays
which lengthwise are in direct line between the pivots supporting them and which
when in their horizontal position overlap one another so that the leading edge of
each tray is on top of the trailing edge of the tray preceding it and which trays are
connected to the carrying chains or bands preferably at the points of junction
between the links of the chains by pivots which project into sockets in the end
frames of the tray and are at one side of its centre of gravity so that the tray will
hang vertically when not supported. These trays and the endless chains or bands
to which they are pivoted are supported along their upper stretch in their forward
movement by horizontal rails or bars until they approach the end of this movement
when the rails or bars terminate and the trays as they successively pass beyond this
termination of these rails drop or turn on their pivots and consequently discharge
their contents which then fall on to the trays which are making the return move-
ment along under rails. As these trays and endless chains are passing downwards
over the returning wheels at the end of the upper or forward movement each tray
is so acted upon by means of a fixed bar or other suitable obstruction that its lower
edge is projected over the upper edge of the tray next in front of it whereby the
overlap is reversed. This reversal of the overlap without which this type of over-
lapping trays would not work is an important part of this invention. By this
reversal these trays when they reassume their horizontal position and commence
the under or return movement along the under rails have each their leading edge
again on the upper side of the trailing edge of the preceding tray same as on their
forward or upper movement on the top rails. Consequently when they reach the
end of this return journey where their supporting rails terminate in same way as at
the end of the forward movement on the top rails, the trays again drop or turn on
their pivots and the contents fall on to the upper surface of another similarly con-
structed endless band of trays next below, or in the case of the last band to the
outlet or discharge part of the apparatus. Immediately after thus discharging its

page_text: load of material cach tray is then so guided that its upper edge is projected past
the lower edge of the tray next in front so that in passing upwards round the
returning wheels at this end of the apparatus the overlap of the tray again so
reversed that on the trays being drawn on to the upper rails to recommence their
forward movement in the horizontal position the leading edge of each tray again
overlaps the one preceding it in the same way as at the outset of the movement.
The above description refers to webs which pass round only a single pair of
returning wheels, i.e. one at each end of a double stretch, but where the web is
carried round more than two returning wheels it only means that so long as the
trays are descending to a lower stretch of the web the same arrangement as
above described for bringing them from first or top rails to second lower rails
is again applied to bring them from the second to the third and from the third
to the fourth, and then when they have again to ascend to the top rail or starting
point the arrangement already described for adjusting the trays in their upward
movement is again applied.
The other part of my invention consists in constructing drying apparatus with
endless conveying chains or bands carrying between them either flat or trough-
shaped trays which are so pivoted to said endless chains and so suspended from
their pivots as to hang swing-like below a direct line between these pivots so that
their drying surface keeps horizontal.
In this form of my improved drying apparatus the supporting rails are only
necessary for the endless bands or chains, and do not touch these trays which swing
clear of them and are consequently entirely supported by their pivots, and I
preferably carry these swinging trays on conveying chains which only pass round a
single pair of returning wheels, i.e. one returning wheel at each end of a double
stretch of said chain, but they also may be similarly utilised and employed in con-
junction with endless conveying chains passing round more than two returning
wheels as hereinafter described and represented in the accompanying drawings.
"
The working of my improved drying apparatus with the above mentioned
"swinging trays is practically the same as with the "flat trays whether the
swinging trays and conveying chains pass round two or more returning wheels, but
when the trays reach the end of their first forward movement they are temporarily
tilted or inverted so as to turn out their contents. One way in which this tilting
may be conveniently effected is to cause the trays to come against projections or
stops so that in their further onward movement the trays are turned over by the
stops, and when they pass these stops they again fall into their horizontal position
and descend round the returning wheels and move along the next under horizontal
stretch with their edges again touching or overlapping, and in this position they
receive the material which is tilted out of the trays which are travelling along the
upper stretch. On reaching the end of the lower stretch these trays are again
similarly tilted and may be carried downwards and round another pair of returning
wheels or carried up to the starting point again as may be desirable. The material
tilted out of the trays in the lowest stretch falls into the outlet or discharge part
of the apparatus.
The method which I however preferably employ for tilting or
overturning these trays is by means of V or T-shaped arms so fitted upon the ends
of the trays that their points project above the pivots on which the trays are
suspended and at same time are placed sufficiently beyond the extreme ends of the
trays to avoid the possibility of coming in contact with the next nearest trays when
they are swinging past one another while going round the returning wheels. The
tilting or overturning of the trays is effected by the lealing points of these
V or T-shaped arms during the forward movement of the trays on either upper or
lower stretches of same coming against projections or stops attached to the sides of
the drying chamber near the end of each horizontal stretch of the trays which turn
the arms over and thereby tilt the trays up on edge ahead of their pivots and owing
to the arms being V or T-shaped this action takes place at the end of their return
movement along the under stretch, same as at the end of their forward movement
along the upper or top stretch.

page_text: When the leading point of these tilting arms has passed the first stop the trays
swing down a little on their pivots and then this point strikes sharply against
another stop and with sufficient force to shake out any of the material that may be
sticking to the tray and this may be repeated if more than one such knock is
considered necessary to completely shake all the material out of the trays. They are
then kept in this tilted position by a bar-like elongation of the last stop, to allow
the succeeding trays free room to be similarly tilted without striking against or
fouling its predecessor. After passing clear of this bar-like elongation the trays
each successively resume their normal hanging position and begin to descend or
ascend around the returning wheel according to whether they are at the end of the
forward or return movement of the conveying chains, after which they again move
along the next horizontal stretch.
The air for drying the material I preferably draw or propel downwards through
same, as it enables me to employ a much stronger air current than if it were used
in an upward direction-which latter may if desired be alternatively used provided
the current is not of sufficient strength to prevent the material falling down through
it from the upper to the lower stretches of the trays.
The accompanying drawings represent several modifications of my improved
drying apparatus constructed in accordance with this invention.
Figure 1 is a section on the line A B of Figure 2, Figure 2 is a section on the
line C D of Figure 1, Figure 3 is a section on the line E F of Figure 1, and
Figure 4 a horizontal section on the line G H of Figure 1, of one form of my
improved drying apparatus in which the edges of flat trays or perforated plates
overlap one another. Two superimposed endless bands of trays are shown but
more can be employed, or in some cases one band will be sufficient.
Figure 5 is a longitudinal section of a modification of the form of apparatus shewn
in Figures 1 to 4 in which instead of two separate endless bands as in Figures 1 to 4
to give four lines of drying surface there is one continuous band or web of over-
lapping trays from start to finish so as to give four lines (or it might be more) of
drying surface.
Figure 6 is a longitudinal section of an arrangement in which there are trough-
shaped swinging trays the edges of which merely touch without overlapping each
other and so pivoted as to always hang swing like as hereinbefore described.
Figure 7 is a longitudinal section on line J K of Figure 8, illustrating similar
trays or troughs to those in Figure 6 but showing the preferred way already
described of tilting these swinging trays and also shewing these trays as overlapping
at their edges.
Figure 8 is a section on line L M of Figure 7.
Figure 9 is a sectional plan on line NO of Figure 7.
Referring first to Figures 1, 2, 3 and 4 a a are the transverse perforated flat
trays; they are attached at their ends to holders b b which are pivoted to endless
chains cc; the pivots being sufficiently near the leading edge of the trays to cause
the trays to drop or tilt into a vertical position when not supported. The holders bb
and endless chains c c travel along and are supported by rails or bars d d both in
their upper forward movement and in their lower return movement and at the
two ends of their course the chains pass over wheels e e (hereinafter referred to as
returning wheels") from either of which said chains receive their motion. The
fixed bearings carrying spindle of the returning wheels at the driving end of the
machine are indicated by the letters e¹; and e² are the moveable bearings carrying
spindle of the returning wheels at opposite end of the drying chamber. are
adjusting screws for shifting the moveable bearings e² for the purpose of tightening
or slacking the chains c c. These returning wheels at one end of the apparatus are
driven by any suitable gearing. The method shown is by a combination of worm
and bevel gearing. Near the end of the upper forward movement of each of the
endless bands, namely at the point f, the upper rails d d are discontinued so as to
no longer support the bands, and similarly near the end of the lower return move-
ment, viz. at the point g, the lower rails d d are discontinued with the same object.

page_text: On reference to the figures it will be seen that the leading edge of each tray at the
upper part of the endless bands overlaps the trailing or rear edge of the tray next
in front so that each tray is free to drop or tilt on its pivots when the support of
the upper rails d d ceases at f. It will also be seen that at the lower or return
part of the endless bands the leading edge of each tray again overlaps the trailing
or rear edge of the tray next in front so that each tray is again free to drop or
tilt on its pivots when the support of the lower rails d d ceases at g. It will
however be readily understood that unless means such as those hereinafter described
which form an important feature of this invention, were provided to reverse the
overlap of the trays between the point and the commencement of the lower
rails d d the leading edge of each tray would be under the trailing or rear edge of
the tray next in front and consequently the trays would be prevented dropping or
tilting on their pivots on passing the point g.
The means for effecting the reversal of the overlaps will now be described. On
passing the point f each tray and its holders tilt or drop backwards on their
pivots from the horizontal position marked 1 against a projection or stop z which it
strikes with usually sufficient force to shake off any material which may be adhering
to the trays and the tea or other material discharged by the dropping of the tray
consequently falls on to the under or returning trays of the endless band. The tray
and its holders after travelling clear of the stop falls by its own gravity into the
vertical position marked 2 and retains the vertical position until the holders come
in contact with a projecting bar or other suitable obstruction which tips the tray
and holders into the position 3 thereby throwing the lower edge of the tray over the
upper edge of the tray next in front, that is to say, the overlap of the two trays is
reversed; after passing the bar h the tray and holders again assume the vertical
position which they retain until the holders come against the guides at the
commencement of the lower rails dd; these guides cause the tray and holders to
move into a horizontal position the leading edge of each tray overlapping the
trailing edge of the tray next in front as shown. On passing the point g the trailing
edge of the tray and holders again drops downwards against a projection or stop x
which it strikes with sufficient force to usually shake off any material which may
be still adhering to the tray and the material discharged by the dropping of the
tray consequently falls on to the upper surface of the trays of the endless band next
below, or in the case of the last band, to the opening t and into the discharge drum 9.
The tray after passing the stop again assumes the vertical position 4 until each tray
and its holders come into contact with the guide bar which so controls the move-
ment of the tray that when it turns on the guide m its upper edge is projected past
the lower edge of the ascending tray immediately preceding it and the overlap is
thereby again reversed so that on the trays being drawn on to the upper rails to
recommence the forward movement in the horizontal position the leading edge of
each tray overlaps the trailing edge of the one preceding it. ss are spreading
wheels (the use of which is however not essential) to spread any of the material
that may fall upon the trays in a lump, they revolve in the opposite direction to the
movement of the trays and are mounted in slotted adjustable bearings whereby
they can be raised or lowered according to the thickness or depth of the material
that is to pass underneath them. These are preferably vanes formed of pieces of
thin sheet iron with blocks between to which they are fastened and which blocks
are attached to the spindle. The top endless band may be supplied by any suitable
feeding or spreading arrangement with the tea or other substance to be dried. In
case of tea or malt it is preferred to adopt the arrangement shown consisting of a
feed hopper n and cruciform or three edged bars p which have a reciprocating
as described in the Specification of my Patent No. 14824
rotary motion
of 1890.
The outlet for the dried tea or other substance may also be of any suitable kind
and will vary according to the particular material operated on. For material such
as tea or malt I preferably employ the arrangement shown in Figure 1; it consists
of a revolving drum or cylinder with a segmental portion of its circumference.

page_text: removed to form an opening of suitable dimensions to allow the material from the
opening t to fall inside of said drum or cylinder which is partially enclosed by a
loose fitting cover r in such manner as to also form the discharge outlet k as shown
from the trays into the opening t and when the opening in the revolving drum q
comes opposite the opening t, the tea or other material then falls through same
into said revolving drum and when the opening in the drum comes opposite the
discharge outlet k the tea or other material then falls out of the drum and is thus
discharged from the machine without letting air pass either in or out.
The arrangement shown in Figure 5 will be readily understood. It differs from
that shown in Figures 1, 2, 3 and 4 in having the endless bands arranged as one
continuous web from start to finish so as to give four lines of drying surface the
trays being tilted at the end of each line in the manner already described, the
tilting trays on leaving the lowest line passing vertically to the top line to resume
their work. The outlet for the dried material is shown in the form of a simple
shoot but may be fitted if desired with the above described rotating discharge drum.
Figures 6, 7, 8 and 9 represent the arrangement of my improved drying apparatus
in which swinging trays are employed. The trays of this type hang swing like on
their pivots by their own gravity so that their carrying surfaces are horizontal and
do not themselves require to rest on guide rails such as d d in Figures 1 to 5. The
links of the endless chains cc therefore are the only parts that have to be supported
by guide rails the trays between same hanging so as to swing freely on their pivots
below a straight line between said pivots. When the trays successively reach the
end of each horizontal travel the forward motion of the chain brings the edge of
the tray against a stop which causes it to become inverted, that is to say to move
from the position 1 to the position 2. The contents are thus turned out so as to
fall on the line of trays below, and the trays on passing the stop may be arranged
to drop on to a second stop or series of same so that it may strike against same with
sufficient force to usually shake off any material that may still be adhering to it,
and on passing the last of these stops the tray resumes its normal horizontal position
by its own gravity.
h
In the modification shown in Figures 7, 8 and 9 which is the form of my
improved drying apparatus which I preferably employ the trays have V or
T-shaped arms or projections u the leading point of which comes against the
projection or stop h which tilts the trays as shown. When they have passed this
stop they swing down a little and the leading point of u strikes against the stop o
with sufficient force to shake out any of the material that may still be sticking to
the tray. As a further provision for more completely effecting this object a series
of stops are provided as shown. The last of the stops o is elongated as shown so as
to keep each tray after it is clear of same in the tilted position for a sufficient
length of time to allow free room for the next succeeding tray to tilt, similarly
without striking against the tray ahead of it. In this modification of my improved
drying apparatus in which swinging trays are used the trays may be made either
trough-shaped or flat and of sufficient width to allow their edges to slightly overlap
one another, as they work efficiently with a slight overlap in the above described
arrangement for operating them. At the discharge outlet shewn in Figure 7
another arrangement is illustrated which I may employ for discharging the material
without at same time admitting any air into the machine. It consists of a number
of revolving vanes (9) fitted on a spindle and partially enclosed inside a loose
fitting cover (r) in such manner that the opening (t) and the outlet (k) are formed
in this loose cover. The material drops from the trays into the opening t and falls
upon the revolving vanes q which on passing round to the outlet k discharges the
material without admitting any air to the macbine. The air for drying the tea or
other material on the trays may be heated or cold and be drawn or propelled
vertically through the travelling trays and the material thereon either downwards
or upwards but preferably downwards in which case it may be delivered into the
top of the drying chamber containing the trays and above the top row of trays,
through an inlet air duct marked in accompanying drawings, and the air after

page_text: passing through the trays escapes from the drying chamber through an opening
marked w below the bottom row of trays or any other equivalent arrangement of
inlet and outlet for the air may be adopted. The special advantage of having the
air current down through the trays is that it does not disturb the material thereon,
while using a strong air current which may be created either by an exhausting or
a pressure blowing apparatus as may be preferred.
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:-
1. In apparatus for drying tea or other substances in which the substance to be
dried is exposed on perforated plates or trays to a current of heated air passed
through the plates or trays which are moved forward and backward in a drying
chamber or box between and by means of endless travelling chains or bands passing
round two or more returning wheels, the employment of an endless web or webs of
pivoted perforated plates or trays as in Figures 1 to 5 the edges of which overlap
one another and which drop on their pivots into a vertical position before reaching
each end of their travel so as to precipitate their contents on to the upper surface
of the return or lower portion of the same web or onto the top surface of the endless
web next below or to the discharge or outlet of the apparatus as the case may be,
in combination with means such as hereinbefore described for reversing the overlap
of the said plates or trays at each end of their travel, as and for the purpose set
forth.
2. In apparatus having one or more endless webs of pivoted plates or trays the
edges of which overlap one another as referred to in Claim 1, the bar h (Figures 1
and 5) or its equivalent for successively tipping the trays so that the lower edge of
each before commencing the return or under movement is thrown over the upper
edge of the tray next in front and the overlap of the trays is thereby reversed as
set forth.
3. In apparatus having one or more endless webs of pivoted trays the edges of
which overlap one another as referred to in Claim 1, the bar (Figures 1 and 5) or
its equivalent for acting on the successive trays so that the upper edge of each is
projected past the lower edge of the ascending tray next in front of it, and the
overlap again reversed, whereby when the trays are drawn on to the upper rails to
recommence the forward movement the leading edge of each tray overlaps the
trailing edge of the one preceding as set forth.
4. In apparatus for drying tea or other substances in which the substance to be
dried is exposed on perforated trays to a current of heated air passed through the
trays which are moved forward and backward in a drying chamber or box between
and by means of endless travelling chains or bands passing round two or more
returning wheels, the employment of an endless web or webs of flat or trough
shaped trays so pivoted to said chains and so suspended from these pivots as to hang
swing-like below a direct line between these pivots and so that the drying surface
of said trays is horizontal and with their edges either touching or overlapping one
another, in combination with means whereby the trays on or before reaching each
end of their travel are tilted or inverted sufficiently for their contents to be turned
or tossed out so as to fall upon the line of trays next below, each tray being
gradually allowed to resume its normal hanging position after being so tilted,
substantially as hereinbefore described and shown in Figures 6 to 9.
5. The several combinations or arrangements of parts substantially as herein-
before described and represented in the accompanying drawings forming improved
apparatus for drying tea or other material.
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Chartered Patent Agent.