FIELD OF INVENTION
The present invention relates to a mechanical system for uniform spreading of tea leaves on the
withering trough and loading and unloading of tea leaf in withering troughs and a process for the
same. More particularly it relates to a system for evenly spreading of tea leaves on movable bed
of a withering trough and conveying the withered leaves from the withering trough to the leaf-
distorting machine (i.e., the rotorvane or the crushing, tearing and curling machine(CTC) for
further processing.
BACKGROUND AND PRIOR ART
It is presently known to the art to load a withering trough by several persons manually once the
fresh green tea leaf has arrived to the factory by tractor-trailers, and to unload the withering
trough and to shift/ transfer the withered leaf to the leaf distorting machine again manually by
several persons, when a desired degree of withering has obtained. Such manual operations
involved in withering trough loading and unloading are too much labour intensive and incapable
of producing a spread leaf bed of good uniformity throughout, and of delivering a continuous
supply of withered tea leaf to the leaf distorting machine.
However, it has been known from the literature to exist a machine for mechanical loading of the
withering troughs. In such known system the electronically operated hydraulically driven
wheeled loading machine, being fed with few quintal fresh green tea leaves at its outset, moves
on heavy rails placed over the withering trough and spreads the leaves on the stationary bed of
the withering frough in multiple passes. In order to load the machine, an elevated roadway
running at the height of top of the hopper was constructed, and green leaf containing bags
transported on trailers or lorries had to be tipped by hand into the machine's hopper from this
elevated roadway by several persons. Also the machine was of considerable size and weight with
heavy wheel loadings, the driver himself being seated on it, therefore, construction of a multi-
storey building sufficiently strong to take these loadings, even if some method could be evolved
to move the machine from floor to floor, was not considered to be economic. Due to such
problem of shifting of such heavy weight systems to different floors/ heights usually such
systems had to be installed on ground which required lining of several systems occupying large
ground area.
However in the present scenario, land is not so cheap, and it must be apparent that
construction of all the troughs in a factory on the ground only, with the construction of
heavy rails for movement of the too heavy leaf spreading machine and the construction of
elevated roadways for its feedings, would neither be economic nor be convenient.
OBJECTS OF INVENTION
Thus the main object of the present invention is to provide for a system for both
mechanically loading and unloading of leaves in a withering trough or a number of
withering troughs which would on one hand be not as heavy as the known system and on
the other hand be simple to load and unload the leaves avoiding manual handling and/or
heavy machinery running and shifting for such purpose.
Another object of the present invention is to provide for a mechanical system for uniform
spreading of tea leaves in one or more withering trough(s) for effective uniform withering.
It is an object of the present invention to provide for a convenient and light system for
mechanical loading and unloading of a number of withering troughs on any floor of a
multi-storey withering house.
It is a further object of the invention to provide for a system for mechanical loading and
unloading of tea leaves in a withering trough, or a number of withering troughs, requiring
minimum human intervention both for loading and for unloading.
SUMMARY OF INVENTION
Thus, according to the present invention, there is provided a system for uniform spreading
of leaves in withering trough(s) for withering, comprising
(a) at least one reciprocating spreading means adapted for continuous to and fro
reciprocating motion over a trough bed;
(b) said spreading means adapted for controlled reciprocating motions;
(c) at least one perforated conveyor belt adapted to function as withering trough
bed for receiving contents from said spreading means;
(d) said withering trough-bed adapted for intermittent forward movement for
selective height of spreading of falling leaves thereon and for continuous
reverse motions for subsequent unloading after uniform spreading and
withering is attained
Thus by the above system of the invention it is now possible to achieve mechanized
loading of leaves in withering trough(s) for withering under uniform spreading and for
subsequent unloading. The spreading means can comprise a spreader hopper adapted for
said reciprocating to and fro movement to achieve the uniform spreading. It is thus
possible using the above system of invention to avoid complex machinery and/or
extensive manual intervention usually involved in supplying leaves in withering troughs.
According to a further aspect there is provided a method for uniform spreading of tea
leaves for withering in withering trough bed using the above system comprising:
i) spreading of fresh tea leaves by continuous reciprocating motion of said
spreading means on withering trough bed up to a predetermined height;
ii) simultaneous intermittent forward motion of the withering trough bed for
receiving tea leaves up to the said height;
iii) even spreading of leaves on trough bed and termination of intermittent forward
motion of withering trough bed at end of spreading;
iv) exposing fresh leaves thus spread on withering trough bed to air blat for
withering;
v) unloading of withered leaves from withering trough bed by continuous reverse
motion of withering trough bed
According to another aspect of the invention there is provided a system for loading and
unloading of tea leaves in withering trough(s), comprising:
(a) means for dumping tea leaves and for conveying them to spreading means; i
(b) at least one reciprocating spreading means adapted for continuous to and fro
reciprocating motion over and across a trough bed;
(c) said spreading means adapted for controlled reciprocating motions;
(d) at least one perforated conveyor bed adapted to ftinction as withering trough
bed for receiving contents from said spreading means;
(e) said withering trough-bed adapted for intermittent forward movement for
selective height of spreading of falling leaves thereon and continuous reverse
motions after uniform spreading and withering is attended for subsequent
unloading,
(f) means for unloading leaves tea leaves from withering trough bed and for
conveying and shifting to leaf distorting machine.
The means for dumping tea leaves comprise a stage on which the leaf is dumped and
wherefrom leaf is supplied/fed to the slant conveyor belt. The means for conveying tea
leaves comprises slant and horizontal conveyers, which convey the fed leaves to any floor
of a building. The horizontal conveyer is provided with scrapper flight conveyer belt,
which scrap the leaves into the spreader hopper for uniform spreading on the withering
trough bed.
According to a further aspect there is provided a method for uniform loading and
unloading of tea leaves on withering trough bed by the above system comprising :
i. dumping fresh green tea leaves on the stage;
ii. feeding slant conveyer belt and conveying to horizontal conveyer belt;
iii. scrapping leaves from horizontal conveyer by scrapper flight conveyer belt into
the spreader hopper;
iv. simultaneous sprinkling of the leaves in strips by spreader hopper having
vibration and reciprocation motion over and across withering trough bed(s);
V. simultaneous intermittent forward motion of withering trough bed for receiving
leaves up to a particular height;
vi. even spreading of leaves on trough bed and termination of intermittent forward
motion of withering trough bed by limit switch at end of spreading;
vii. exposing fresh leaves thus spread on the withering trough bed to air for
withering;
viii. unloading of withered leaves from withering trough bed to trough unloader
and leaf shifter conveyer belt by continuous reverse motion of withering trough'
bed;and
ix. collecting and conveying of withered leaf by trough unloader and leaf shifter
conveyer.belt onto leaf distorting machine.
DETAILED DESCRIPTION OF INVENTION
The system of the present invention is capable to load and unload tea leaf withering trough
or troughs at any floor of a multi storey building and operated by a single operator.
Accordingly the system is provided with a slant conveyor belt and an overhead horizontal
conveyor belt, placed in succession, which act as the means to convey the supply of fresh
green tea leaves. The leaves are fed from a dump on a stage, which is the platform for
feeding the leaves, by a person on to the lower part of the slant conveyor belt, to the said
spreading means. The said spreading means is a leaf spreader hopper.
There is provided a scrapper flight belt conveyor, with handles or flights, placed over and
across the horizontal conveyor belt. This remains standing and extended from a single
vertical support on the frames of the leaf-spreader hopper, to scrap down green tea leaves
from the overhead horizontal conveyor into the leaf-spreader hopper.
The spreader hopper remains suspended on springs fitted on a frame and continually
reciprocates on rails placed over and across the bed of the withering trough near its
entrance end with simultaneous vibration motion.
The trough bed is a movable wire mesh bed wrapped around end rollers (pulleys ), like a
conveyor belt, which can be given intermittent forward motion and slow and continuous
reverse motion. This receives the tea leaves which are spread automatically on it by the
vibration and reciprocation motion of the spreader hopper and expose the leaves to air for
withering.
The said means for unloading a withering trough and for conveying the withered leaves
from withering trough bed is a trough unloader cum leaf shifter conveyor belt placed
below and in front of the trough bed.
The system of the present invention may also be used for loading and unloading several (2
to 20, or even more) withering troughs. Accordingly several similar withering troughs are
placed in parallel. For this the leaf-supplier overhead horizontal conveyor belt and the
leaf-spreader reciprocating-hopper supporting rails are extended over all the troughs
placed in series, and also the 'withered leaf collector cum shifter' belt conveyor is
extended in front of all the troughs. The same leaf-spreader hopper is used for spreading
the leaf on the beds of the troughs in turn, one by one, each time by using the same two
easily shiftable limit switches (e.g., limit switches with wheeled carrier supports, which
can be easily slided along the rails and easily clamped and undamped) in order to confine
reciprocation of the hopper on the rails over and across the corresponding trough. During
unloading, the trough beds are run backwards(slowly but continuously) one after one, in
turn, and the leaf collector cum shifter belt conveyor is run in order to shift/convey the
withered leaf from each trough to the leaf distorting machine.
The system of the present invention is such that the linear speeds of slant conveyor belt,
overhead horizontal conveyor belt, leaf scrapper flight conveyor belt and trough-unloader
cum leaf shifter conveyor belt are adjustable and/or presetable . Also the intermittent
forward and continuous reverse motions of withering trough bed is adjustable according to
the parameters selected from depth, width and the like of the leaves received. In addition
the vibrations or jerks of the leaf-spreader hopper and the time required for each pass of
the leaf-spreader hopper on the rails over and across the bed of the withering trough is
adjustable and may be preset.
The two main control circuits associated with the present invention are
(1) a control-circuit used to control the reciprocating motion of the leaf-spreader
hopper on the rails, by controlling reciprocation of the concerned motor, being
alternately activated in one direction and deactivated in the other direction by
touch of either of the two indicators attached with the frames of the hopper
with either of the limit switches placed on the rails over and across the frough
bed;and
(2) a control-circuit to be used with the trough-bed driving motor for obtaining and
presetting the intermittent forward and continuous reverse movements of the
withering trough bed.
The system of the invention and its working is described with reference to non-limiting
illustrative figures.
Description of Figures
Fig. 1: Front elevation view of the mechanical loading-unloading system of invention;
Fig. 2; Rear elevation view of the mechanical loading-unloading system of invention
Fig 3: Control-circuit diagram for the dc motor providing reciprocating motion to the
hopper assembly on rails
Fig 4: Control-circuit diagram for the dc motor used for providing intermittent forward
and continuous reverse motion to the withering trough bed
The structure and working of the mechanical loading-unloading system for tea leaf
withering trough of the present invention is described with reference to Figs. 1 and 2,
The system comprises a stage (1) on which the lower end of a slant conveyor belt (2) rests.
Fresh tea leaf collected from the field is dumped on this stage. The slant conveyor belt (2)
leads to the horizontal conveyor belt (3) over and across which a scrapper flight belt (4),
fitted with the spreader-hopper's (5) frame, is extended to scrap the leaf by its handles into
the hopper. The slant conveyer may help to convey the leaves from the stage to any floor
of a multistorey building depending on its length. The slant and the horizontal leaf
conveyor belts are run by a controllable-speed dc motor (10) and control unit. Belt-and-
puUey drives are present which transmit power to the slant and overhead horizontal
conveyor belts from the motor (10). The spreader-hopper (5) is fitted on a frame and is
capable of continuous reciprocating motion on two rails (6) placed over and across the
trough bed near its entrance end by means of a dc motor (8) with a gear box and variac
(17) (autotransformer) controlled by control circuit (16) (detailed electrical circuit diagram
shown in Fig. 3). Chain-and-sprocket drives are present which transmit power to rope-
pulley-and-drum roller arrangement (7) attached with the reciprocating leaf-spreader
hopper, from the dc motor (8) for obtaining such continuous reciprocation for the hopper.
A pair of limit switches placed is on the rails, which limit the length of reciprocation of the
leaf spreader hopper on the rails, over and across the trough bed. The spreader hopper,
which hangs on four springs within its frame is given simultaneous vibration motion by
means of a crank mechanism run by another small dc motor (9) with a control unit (19)
placed on its frame. This second motor (9) and control unit (19) are also used for giving
motion to the scrapper flight belt. There are belt-and-puUey drives which transmit power
to the leaf scrapper flight belt, fi-om the motor (9). The vibrating and reciprocating leaf
spreader hopper (5), being placed below the horizontal leaf-supplier conveyor belt (3),
gets supply (feed) of tea leaf all the time irrespective of its different locations on the rails
(6) and shuffles and sprinkles tea leaf on the perforated trough bed placed below it. The
trough bed i.e. the withering trough bed (12) is made of wire-mesh netting, wrapped
around, and movable on end rollers (pulleys). It has inclined walls on three sides so as to
form the trough (11).A dc motor, (13), with a gear box and a control unit is used to give
intermittent forward and continuous reverse motions to the withering trough bed. Chain-
and-sprocket drives transmit power to the rollers of the withering trough bed, from the
motor (13). A pair of limit switches is placed at the ends of the trough bed, which limit
the forward and reverse movements of the trough bed, by being activated and deactivated
by a 'stopper' attached with the chain drive used for moving the end rollers (pulleys) of
the trough bed. The stepped/ intermittent forward motion and the reverse continuous
motion of the trough bed driving dc motor (13) is obtained and controlled by an electrical
circuit (18) (Fig. 4). The circuit board (20) for the whole system is also provided. An
unloader and leaf shifter conveyor belt (14) is placed below the withering trough bed at its
entrance end. A dc motor (15 ) with a control unit, is used to drive the trough-unloader
cum leaf shifter conveyor belt. Chain-and-sprocket drives are present which transmit
power to trough-unloader cum leaf shifter conveyor belt, from the dc motor (15).
Besides the 20 listed components, however, there few other components of the system,
like two dc motor control units for the motors used for driving the withering trough bed
and the wheeled reciprocating hopper assembly on rails, two pairs of limit switches, and a
second circuit board, along with necessary cables and wires
Loading and unloading tea leaves in the withering trough by the above system:
The operator, continually feeds the slant conveyer belt with fresh tea leaf by throwing
handfiils of leaves from the dump on the platform. These leaves are conveyed by the slant
conveyer to the horizontal conveyer. The scrapper flight belt scraps these leaves on the
spreader hopper. The leaf spreader hopper on the rails is allowed to continuously
reciprocate and spread (sprinkle) tea leaf on the trough bed, in a strip of width as much as
the hopper outlet width simultaneously with receiving leaves by the scrap conveyer. The
trough bed is kept stationary until a certain height (thickness) of a strip of tea leaf is not
obtained on it. Then the bed is moved forward by a distance equal to the average width of
the strip and then stopped for spreading another strip of the same height (thickness)
adjacent to the previous strip, and then again moved by a distance equal to the average
width of the strip and again stopped for spreading another strip of the same height adjacent
to the previous strip, as before. In this way strip after strip of same height and width are
laid adjacent to each other across the trough bed until a limit switch causes termination of
the spreading process, when the whole trough area has got evenly spread with the green
tea leaf up to a particular spread depth-
Theoretically the tea leaf spread on the withering trough bed will be subjected to fan-
driven air flow throughout a period of 12 to 20 hours for v^thering. Then, for unloading
the trough, the trough bed will be given continuous slow motion in the reverse direction;
as a result the withered tea leaf will slowly and gradually fall on the unloader and leaf
shifter conveyor belt (14) placed below the bed of the trough at its entrance end. This
trough unloader and leaf shifter conveyor belt will collect and convey the withered tea leaf
onto a stage near the slant feeding conveyor of the leaf distorting machine (not shown),
and a person will continually throw the withered tea leaf from this stage onto the slant
feeding conveyor belt of the leaf distorting machine.
The same loading-unloading arrangement can easily be extended over a number of troughs
on the same floor by extending the rails and the trough unloader cum leaf-shifter conveyor
belt, and by loading the troughs in tum each time by placing the same pair of limit
switches on rails across the particular trough in order to confine reciprocation of the
spreader hopper over and across that trough only.
Description and working of the Control Circuit for Reciprocating Motions for the
Leaf Spreader Hopper with Respect to Fig. 3
In Fig. 3, when the power switch is made on, the ac single-phase 220 V supply is
converted by a bridge converter circuit (rectifier), consisting of 4 diodes, D?, Dg, D9, and
Dio, to dc 220 V, which is applied across the field terminals of the dc motor (lower-right
diagram). In a separate power tapping (lower-left diagram), when the ac single-phase 220
V supply is applied across the two terminals of the autotransformer (AT), the transformed
(stepped down) output voltage passes through a bridge rectifier, consisting of 4 diodes, D3,
D4, D5, and De, which converts the ac supply power to dc power at the two terminals, A
and B, marked with +ve and -ve, respectively, which in turn are connected across the
terminals of the armature windings of the dc motor through the two relays, R3 and R4,
which alternately changes polarity (+ve to -ve, and vice versa) of the two terminals, C and
D, depending on stimulations imparted to these two relays from the main circuit (upper-
left diagram), and thus the alternate forward and reverse motions of the motor(M)
armature and shaft is obtained..
When the power switch Si (upper-left diagram) is put on, ac 220 V single-phase supply is
applied to the primary of the centre-tapped transformer (T). The stepped-down output ac
voltage gets converted to dc voltage by the half-bridge rectifier consisting of the two
diodes Di and Da, and this converted dc voltage becomes available at the single-pole
double-throw (SPDT) switch S2, which can be given connection alternatively to either
manual mode or automatic mode.
1. Manual Mode
When the manual mode is set on, the forward or reverse motion obtainable would depend
on which of the Forward and Reverse switches (S3 and S4) is pressed to its 'on' position.
When the forward switch is put on, relay R3 is energized and, according to the circuit
arrangement as shown, forward motion is obtained. And, when the Forward switch (S3) is
kept off and the Reverse switch (S4) is put on, relay R4 is energized and, according to the
circuit arrangement, reverse motion is obtained.
2. Automatic Mode
When the 'Auto' mode is set on, and the Push To Start switch (PS) is once pressed in
order to start the operations, the main circuit (upper-left diagram) automatically gives
alternate forward and reverse motions, as would be accentuated by the two limit switches,
LSi and LS2. When a pointer attached with the frame of the leaf spreader hopper, which is
to be reciprocated on the rails, strikes against the limit switch LSi, switch LSi gets
activated, relays Ri and R3 get energized and, according to the circuit arrangement,
forward motion of the motor shaft is obtained and retained until another pointer attached
on the opposite side of the frame of the leaf spreader hopper strikes against the limit
switch LS2, when LS2 would be activated, relays R2 and R4 would get energized, and as a
result, according to the circuit arrangement, reverse motion would be obtained and
retained until the opposite pointer on the frame of the hopper would again strike against
the limit switch LSi; switch LSi would be activated, switch LS2 would be deactivated,
relays Ri and R3 would get energized and forward motion of the motor shaft would be
again obtained and retained until the pointer attached on the opposite side of the frame of
the hopper strikes against the switch LS2, when again reverse motion would be obtained,
and so on. In this way, continuous reciprocating motions for the leaf spreader hopper
would automatically be obtained between the two pints on the rails, as marked by the two
limit switches LSi and LS2 fitted at those points on the rails.
Description and working of the Control Circuit Used for Obtaining Intermittent
Forward and Continuous Reverse Motion of the Withering Trough Bed with Respect
to Fig. 4
Major components and arrangements of the developed control-circuit assembly have been
shown in circuit diagrams in Fig. 4. All the circuit components, excluding the two limit
switches, are kept in an insulated box, in front of which there is a panel of external
terminals, labeled as 1, 2, 3, ..., 12. The ac 220 V supply is directly connected to terminals
7 and 8, and to the 'dc motor power-supply cum speed-control unit' (readily procured,
external to developed circuits, so not shown). When the power switch is put on, a bridge
rectifier in the power-supply cum speed-control unit converts the ac 220 V to dc 220 V,
which is applied across the field windings of the motor. The ac 220 V available in the
power-supply cum speed-control unit is separately transformed by an autotransfomier
within the unit, and the variable ac output voltage (0 to 220V) gets converted by another
bridge rectifier to variable dc voltage (0 to 220V), which is applied across the terminals 3
and 4. This variable dc voltage available at terminals 3 and 4 is then taken through the
Forward Contactor (Cont-1) or through the Reverse Contactor (Cont-2) to terminals 1 and
2, or equivalently to terminals A and Ai of armature windings of the motor. The reversal
of direction of rotation of the dc motor is obtained by changing the polarity of armature
terminals of the motor utilizing the forward contactor and the reverse contactor alternately.
While speed of the dc motor would be determined by the magnitude of the armature input
voltage (0-220V) obtained simply by various settings of the autotransformer, whether
forward motion or reverse motion would be obtained will depend on which one of the
forward and reverse contactors is made operative. In order to control operations of the
Forward Contactor (Cont-1), a timer circuit and two relays (R-1 and R-2) and a limit
switch are used; and, in order to control operations of the Reverse Contactor (Cont-2), a
relay (R-3) and a limit switch are used. The dc 12 V power necessary to operate all these
relays, timer circuits and limit switches is obtained from a '12 V DC Power Supply' unit,
which gets the ac 220 V input from terminals 7 and 8 and produces the dc 12 V output to
be available across +a and -a.
However, the working principles of obtaining intermittent forward and continuous reverse
motions through use of the developed circuits are presented below, based on above
descriptions.
(a) Intermittent Forward Motion
If the red "Push to Forward Start" switch is pushed once, the relays R-2 and R-1 and the
timer circuit will be activated to control operations of Forward Cont-1. As long as the
timer circuit will allow the coil of contactor 1 (Cont-1) to get energized, the activated coil
will cause closure of all the contacts of the contactor (but will open the normally close
(N/C) contact of auxiliary contactor 2), thus making straight paths for the power to be
transmitted from terminals 4 (+ve) and 3 (-ve) to terminals 1 and 2, thereby imposing
positive and negative polarity to terminals A and Ai, respectively, and producing the
forward motion. But as soon as the timer circuit will (temporally) break the power circuit
with the coil of contactor 1 (Cont-1), all the contacts of contactor Iwill get dislodged and
no power will be transmitted from terminals 3 and 4 to terminals 1 and 2, or to armature
terminals A and Ai, and so there will be (temporarily) no motion of the armature or the
motor shaft (i.e., intermittent stop condition), until again the timer circuit allows the coil of
contactor 1 to get energized, and thus again producing forward motion (run). The run time
and stop (idle) time can be set to desired values by selecting suitable values of the variable
resistors (potentiometers) of the timer circuit. Intermittent forward motion thus obtained
will continue until the red push switch is not pressed again or a terminator pointer does not
strike the Forward Limit Switch in order to break the circuit involving the relay R-2.
(b) Continuous Reverse Motion
When power is already available across the field windings of the motor and also at
terminals 3 and 4, if the green "Push to Reverse" switch is pressed and kept pressed, relay
R-3 will be operative and as a result all the contacts of contactor 2 (Cont-2) will be closed,
(but the normally closed contact of auxiliary contactor 1 will be opened), thus making
round paths through Cont-2 for the power to be transmitted from terminals 3 (-ve) and 4
(+ve) to terminals 1 and 2, respectively, thereby imposing negative and positive polarity to
terminals A and Al, respectively, and producing the reverse motion. This reverse
(backward) motion will continue as long as the green push switch is kept pressed, but if
the switch is released or if the terminator pointer strikes the Reverse Limit Switch, the
circuit involving the relay R-3 will break, and no motion would be obtained.
We Claim
1. A system for uniform spreading of tea leaves in withering trougli(s) for witliering,
comprising:
a) at least one reciprocating spreading means adapted for continuous to and fro
reciprocating motion over a trough bed;
b) said spreading means adapted for controlled reciprocating motions;
c) at least one perforated conveyor bed adapted to function as withering trough bed
for receiving contents from said spreading means;
d) said withering trough-bed adapted for intermittent forward movement for selective
height of spreading of falling leaves thereon and continuous reverse motions
after uniform spreading and withering is attended for subsequent unloading.
2. A system for loading and unloading tea leaves in withering trough, comprising:
a) means for dumping tea leaves and for conveying them to spreading means;
b) at least one reciprocating spreading means adapted for continuous to and fro
reciprocating motion over a trough bed as claimed in claim 1;
c) said spreading means adapted for controlled reciprocating motions;
d) at least one perforated conveyor bed adapted to function as withering trough bed
for receiving contents from said spreading means as claimed in claim 1;
e) said withering trough-bed adapted for intermittent forward movement for selective
height of spreading of falling leaves thereon and continuous reverse motions
after uniform spreading and withering is attended for subsequent unloading;
f) means for conveying tea leaves from trough bed and unloading.
3. A system as claimed in claims 1 or 2 wherein said spreading means is a
spreader hopper and adapted to reciprocation motion on rails and vibration motion
simultaneously while spreading tea leaves on the trough bed.
4. A system as claimed in claims 1 to 3 wherein said spreading means is adapted to
vibration motion.
5. A system as claimed in claim 4 wherein said spreader hopper is adapted to vibration
motion by means of a crank mechanism attached with it and controlled by a motor
with a control unit.
6. A system as claimed in claims Ito 5 wherein said spreader hopper is operatively
connected with a motor and a control circuit, adapted to control speeds and motions
of the motor for reciprocating motions of the spreader hopper
7. A system as claimed in any preceding claim wherein said reciprocating motion of the
leaf spreader hopper on the rails is confined between two selected points limited by
limit switches.
8. A system as claimed in any preceding claim wherein said leaf spreader hopper is
adapted to receive continuous supply of tea leaves and shuffle and sprinkle the same
in strips on the trough bed placed below.
9. A system as claimed in claim 8 wherein the spreader hopper is adapted to sprinkle
leaves on the trough bed in strips of width corresponding to the width of the hopper
outlet.
10. A system as claimed in any preceding claim wherein said trough bed adapted to
function as the withering trough bed comprises wire mesh netting, wrapped around
and movable on, end rollers or pulleys.
11. A system as claimed in any preceding claim wherein said movable withering trough
bed is operated by a driving motor and an operative control circuit adapted to control
speeds and motions of the motor for intermittent motions during forward movement
and continuous motions during backward movement of the trough bed.
12. A system as claimed in any preceding claim comprising a pair of limit switches
placed at the ends of the withering trough bed to limit the forward and reverse
movements of the trough bed.
13. A system as claimed in any preceding claim wherein the withering trough bed is
adapted to remain stationary to receive tea leaves up to a certain thickness/ height
from said spreader hopper and move forward thereafter to receive the next strip of
leaves.
14. A system as claimed in claim 13 wherein said withering trough bed is adapted for
such intermittent motion to receive strips of leaves adjacent to one another till
termination of leaf spreading.
15. A system as claimed in claim 14 wherein termination of leaf spreading on the
withering trough bed is carried out on receiving leaves up to a particular depth by a
limit switch.
16. A system as claimed in any preceding claim wherein the withering trough bed is
adapted to expose tea leaves to air flow for withering.
17. A system as claimed in any preceding claim wherein the withering trough bed is
adapted to unload the leaves after withering by continuous slow motion in the reverse
direction to drop withered leaves to conveyer for unloading.
18. A system as claimed in any preceding claim comprising plurality of withering trough
beds.
19. A system as claimed in claim 18 wherein plurality of withering trough beds are
adapted to receive tea leaves from a common leaf-spreader hopper for spreading the
leaf on the beds of the troughs in turn, one by one, each time by using the same two
easily shiftable limit switches in order to confine reciprocation of the hopper on the
rails extended over and across the corresponding trough.
20. A system as claimed in claim 19 wherein the plurality of withering trough beds are
adapted to unload the leaves after withering by continuous slow motion in the reverse
direction of each of the withering trough beds one by one.
21. A system as claimed in any preceding claim wherein said means for dumping and
conveying of leaves comprise stage and conveyer belts.
22. A system as claimed in claim 21 wherein tea leaves are dumped on the said stage, to
be conveyed to the leaf spreader hopper by means of an upward inclined slant belt
conveyer and an overhead horizontal belt conveyer.
23. A system as claimed in any one of claims 1 to 22 wherein the said conveyers are
arranged as upward slant and overhead horizontal.
24. A system as claimed in any preceding claim wherein the overhead conveyer,
preferably horizontal, is provided with a flight scrapper flight belt conveyor.
25. A system as claimed in any preceding claim wherein the scrapper flight belt conveyer
is fitted on spreader hopper frame and comprises handles or flights adapted to scrap
leaves from the horizontal conveyer to the leaf spreader hopper.
26. A system as claimed in any preceding claim wherein the said scrapper flight belt is
controlled by the motor controlling vibrating motion of the spreader hopper.
27. A system as claimed in any preceding claim wherein the means for unloading
comprises trough unloader cum leaf-shifter conveyor belt and collecting stage, or
hopper of the leaf distorting machine.
28. A system as claimed in any preceding claim wherein the trough unloader cum leaf-
shifter conveyor belt is adapted to receive withered leaves from more than one trough
in series.
29. A system as claimed in any preceding claim wherein the control circuits for alternate
forward and reverse motions from the same motor for the withering trough bed and
reciprocating motion from another motor for the leaf spreader hopper use forward
and reverse contactors alternately to change polarity of the armature terminals of the
motors.
30. A system as claimed in any preceding claim wherein the control circuit for producing
intermittent forward motion of driving motor of the withering trough bed comprises
timer circuit, contactors, relays, limit switches, etc.
31. A system as claimed in any preceding claim wherein the control circuit for producing
intermittent forward motion of driving motor of the withering trough bed is adapted
>
such that pressing a forward start switch lead to the timer circuit activating the coil of
"contactor causing closure of all the contacts of the contactor but opening the
normally close contact of auxiliary contactor, making straight paths for the power to
be transmitted producing the forward motion; the timer circuit temporally breaking
the power circuit with the coil of contactor, leading to dislodging of all the contacts
of contactor preventing transmittal of power causing temporarily stoppage of motion
of the armature or the motor shaft or intermittent stop condition, until again the timer
circuit allowing the coil of contactor to get energized for producing forward motion
or the run; the intermittent forward motion continuing until further pressing of the
start switch or a terminator pointer striking the forward limit switch.
32. A system as claimed in any preceding claim wherein the control circuit for producing
intermittent forward motion of driving motor of the withering trough bed is adapted
to set run time and stop or idle time to desired values by selecting suitable values of
the variable resistors i.e. potentiometers of the timer circuit.
33. A system as claimed in any preceding claim wherein the control circuit for producing
reverse motion of driving motor of the withering trough bed comprises a relay,
contactors, limit switches, etc.
34. A system as claimed in any preceding claim wherein a control circuit for producing
reverse motion of driving motor of the withering trough bed is adapted such that
pressing the reverse switch when power is available across the field windings of the
motor and also at terminals, leads to operating of relay thereby closing all the
contacts of contactor but opening the normally closed contact of auxiliary contactor,
making round paths for the power to be transmitted producing the reverse motion;
reverse or backward motion continuing until releasing of the reverse switch or the
terminator pointer striking the reverse limit switch.
35. A system as claimed in any preceding claim wherein a control-circuit for the
reciprocating motion of the spreader hopper on the rails is adapted to control
reciprocation of the concerned motor, by alternately activating the motion in one
direction and deactivating in the other direction by touch of either of the two
indicators attached with the frames of the hopper with either of the limit switches
placed on the rails over and across the trough bed.
36. A system as claimed in any preceding claim wherein the control circuit for spreader
hopper is adapted to run in manual mode and or automatic mode.
37. A system as claimed in claim 36 wherein the control circuit for spreader hopper
adapted to be used in manual mode comprises forward switch and relay for
controlling forward motion and reverse switch and relay for controlling reverse
motion.
38. A system as claimed in claims 36 and 37 wherein the said control circuit is adapted
such that putting the forward switch in on position leads to energizing relay resulting
in forward motion and putting the forward switch in off position and the reverse
switch in on position leads to energizing relay resulting in reverse motion.
39. A system as claimed in claiin 36 wherein the control circuit for spreader hopper
adapted to be used in automatic mode comprises limit switch and relay for
controlling forward motion and another limit switch and relay for controlling reverse
motion.
40. A system as claimed in claim 36 wherein the control circuit for spreader hopper
adapted to be used in automatic mode is such that pressing the start switch lead to
starting the operations of the main circuit automatically giving alternate forward and
reverse motions, accentuated by the two limit switches; wherein a pointer attached
with the frame of the spreader hopper, which is to be reciprocated on the rails,
striking against the limit switch and activating it leads to relays getting energized
resulting in forward motion of the motor shaft; the forward motion continuing until
another pointer attached on the opposite side of the frame of the leaf spreader hopper
striking against the other limit switch thereby activating it leads to relays getting
energized, resulting in reverse motion; such reverse motion continuing until the
opposite pointer on the frame of the spreader hopper again striking against the first
limit switch resulting in continuous reciprocating motions for the spreader hopper
automatically between the two on the rails, as marked by the two limit switches
fitted at those points on the rails.
41. A system as claimed in any preceding claim wherein the linear speeds of slant
conveyor belt, overhead horizontal conveyor belt, trough-unloader cum leaf shifter
conveyor belt and leaf scrapper fiight belt are presetable and /or,adjustable.
42. A system as claimed in any preceding claim wherein the vibrations or jerks of the
leaf-spreader hopper and the time required for each pass of the leaf-spreader hopper
on the rails over and across the bed of the withering trough are presetable and /or
adjustable.
43. A system as claimed in any preceding claim wherein the intermittent forward and
continuous reverse motions of withering trough bed are adjustable according to the
parameters selected from depth, width and the like of the leaves received.
44. A method for uniform spreading of tea leaves for withering in withering trough bed
using the system as claimed in any proceeding claim comprising:
i) spreading of fresh tea leaves by continuous reciprocating motion of said
spreading means on withering trough bed up to a predetermined height;
ii) simultaneous intermittent forward motion of the withering trough bed
for receiving tea leaves up to the said height;
iii) even spreading of leaves on trough bed and termination of intermittent
forward motion of withering trough bed at end of spreading;
iv) exposing fresh leaves thus spread on withering trough bed to air blat for
withering;
v) unloading of withered leaves from withering trough bed by continuous
reverse motion of withering trough bed
45. A method of loading and unloading of tea leaves using the system as claimed in
claims 1 to 44 comprising the steps of
a) dumping fresh green tea leaves on the stage; !
b) feeding first to a slant conveyer belt and then conveying to a horizontal
conveyer belt;
c) scrapping leaves from horizontal conveyer by a scrapper flight belt
conveyer into the spreader hopper;
d) simultaneous sprinkling of the leaves in strips by spreader hopper in
vibration and reciprocation motion over and across withering trough bed(s);
e) simultaneous intermittent forward motion of withering trough bed on
receiving leaves up to a particular height;
f) even spreading of leaves on trough bed and termination of intermittent
forward motion of withering trough bed by limit switch at end of spreading;
g) exposing fresh leaves thus spread on the withering trough bed to air for
withering;
h) unloading of withered leaves from withering trough bed to trough unloader
and leaf shifter conveyer belt by continuous reverse motion of withering
trough bed; and
i) collecting and conveying of withered leaf by trough unloader and leaf
shifter conveyer belt onto leaf distorting machine.
46. A system and method for uniform spreading of tea leaves on withering trough(s) and
mechanical loading and unloading for tea leaves withering trough(s) substantially as
herein described and illustrated with reference to the accompanying figures.

A mechanical system for uniform spreading of tea leaves on the withering trough(11)
and a system for loading and unloading of tea leaf in withering troughs(11). More
particularly a system for evenly spreading of tea leaves on movable bed (12) of a
withering trough (11) and conveying the withered leaves from the withering trough (11)
to the leaf-distorting machine for further processing. A process for uniform spreading of
tea leaves on withering trough(s) and mechanical loading and unloading of tea leaves on
withering trough(s) by the said system.