The present invention relates to a novel gravimetric weigh feeder equipped with microcontroller for feeding vegetative matter at desired feed rate to rotorvane for maceration. More particularly this invention pertains to a system or apparatus for gravimetric feeding of tea leaves to rotorvane for maceration (cutting) at a desired rate aided by a microcontroller included in the system for ensuring close quality control resulting in better preconditioning of withered tea leaf. This invention also concerns a process for producing uniform grade of CTC tea with the help of the gravimetric feeder described and illustrated herein, which process is substantial guided and carried out with the help of the microcontroller forming an important component of the present system.
During processing of tea, tea leaves are plucked by workers from field (tea plantation) and after plucking the leaves these are kept for at least 8 to 10 hours for both chemical and physical withering. After completion of withering, maceration or cutting is commenced by deploying "rotorvane" and CTC machine, followed by Fermentation (oxidation), drying and sorting. After sorting tea leaves into different grades, the sorted leaves are packed in suitable containers and sent to market for storage and sale, both in bulk and retail.
To achieve proper preconditioning of withered leaf and satisfactory cut in CTC machine, it is imperative that a uniform rate of feeding of tea leaves to rotorvane is maintained. Almost universally practiced manual feeding, even under best of supervisory controls, can hardly ensure more than 70% accuracy in the feed rate.
At present almost in all tea factories in India the withered tea leaves are fed manually by means of fixed speed conveyor or through withered leaf shifter. It is virtually impossible to maintain a uniform rate of feeding tea leaves into rotorvane, a downstream machine, although everybody aims at feeding the withered tea leaves uniformly to produce better quality tea and also to enhance productivity. Since the tea leaves are heterogeneous in nature and after withering the leaves become leathery / rubbery, it is not possible to feed leaves at a constant rate, even if a buffer hopper is used before introducing the mass into rotorvane.

The present invention aims at overcoming the difficulties envisaged in the present day practice by developing a system which will ensure uniform feed rate of withered tea leaves into rotorvane.
The principal object of this invention is to provide a novel gravimetric weigh feeder equipped with microcontroller for feeding vegetative matters like tea leaves to rotorvane for maceration.
A further object of this invention is to provide a microcontroller-based gravimetric weigh feeder for achieving a uniform feed rate of tea leaves into rotrovane for uniform maceration.
A still further object of this invention is to provide a microcontroller-based gravimetric weigh feeder which by virtue of close process control achieves an accuracy level of 95% with a limit of ±5% through elimination of irregular and uneven manual feeding of tea leaves by these workers.
Another object of this invention is to provide a novel weigh feeder which not only maintains a uniform feed rate of tea leaves to rotorvane, but also continuously records the total weight of tea leaf processed along with total operational time, over feed time, under feed time, paused time and zero feed time in non-volatile memory. The system can also be connected with PC through Serial Port for central monitoring of all such parameters for analysis.
Yet another object of this invention is to provide a novel gravemetric weigh feeder equipped with a load cell acting as the controlling means for controlling feed rate, thereby enhancing the quality and productivity, simultaneously bringing about energy saving and reduction in the maintenance cost of machines.
Still another object of this invention is to provide a novel gravimetric weigh feeder equipped with a microcontroller having facilities for restoration of data in case of power failure, and also for identification of errors and faults in the course of operation.

The forgoing objects are achieved by the present invention which pertains to a novel gravimetric weigh-feeder equipped with microcontroller for feeding vegetative matters at desired feed rate to rotorvane for uniform maceration, thereby ensuring quality enhancement, energy saving and reduction in the maintenance cost of the machines, characterized in that the said feeder comprises :
(a) a main frame carrying a tie and side guard pillar post;
(b) a conveyor belt rotating on two rollers with bearing equipped with tensioning screw and having a top cover sheet;
(c) plurality of rollers of which the first one is fixed idler roller, the second one is return idler roller and the third is the swiveling idler roller housed in the swiveling idler roller arrangement with a bracket for return idler roller ;
(d) a feeder equipped with leaf guide plate having back and side guide guards and a side guard extension discharge unit;
(e) a drive means mounted on a suitable base, and
(f) a controlling means mounted on a base for achieving controlled release of the vegetative matter for maceration cutting.
The vegetative matter referred to above is tea. The system of this invention may also be extended to other leafy vegetative matters such as tobacco leaves and for controlling the feed rate for any free flowing solid material.
The operation of the feeding unit of the gravimetric weigh feeder of this invention is guided by the aforesaid controlling means which is a load cell mounted on a load cell fixing base, said load cell being meant for ensuring smooth operation of the system effecting a uniform feed rate of tea leaf and continuous recordal of the net weight of tea leaf processed in total operation time.
The drive means mentioned hereinabove is a 0.37 kw geared motor operating at around 1400 R.P.M. and 415 volt ± 10% LP. Proximity switch fixing brackets are provided on G. M. (geared motor) side as well as on side opposite thereto, bearing suitable guards for safety purposes.

The invention will be particularly defined and illustrated by means of the accompanying drawings wherein -
Fig.l depicts the cross sectional view of the apparatus of this invention from the
feed end,
Fig.2 shown the side view of the entire assembly,
Fig. 3 gives a cross-sectional view from top and
Fig.4 illustrates in detail the block diagram of the operating system, showing the deployment of individual components of the electronic and mechanical assemblies.
Referring to Figs. 1 to 3 of the drawings, the description of. the individual component, quantity of such components, their material of construction and the identifying numerals in respect of said components are given below in a tabular form, where the undernoted abbreviations have been used for the sake of brevity and convenience -
S.S. = stainless steel; M.S. = mild steel ; G.M. = geared motor ;
STD. = standard ; P.V.C. = poly vinyl chloride



The invention will be further amplified by means of the following Example given by way of illustration and not by way of limitation, which elaborates the sequential operating mode of the system. It is to be noted that the different stages of operation are controlled by Micro - Controller, which goes a long way to eliminate human error.
EXAMPLE SEQUENTIAL STEPS FOR RUNNING THE SYSTEM
A) After power on, the system goes to Ready State, i.e. Ready to start. To start the weighing operation, START key is pressed once. After pressing START key, the system will first take the tare weight of the belt. During this period, there should not be any material on the belt, which will otherwise introduce error in measurement. After taking the online belt tare weight, the system will automatically switch to the batch weighing operation. During operation, to see the detailed information of the

same batch, up/down arrow key is just pressed to scroll through 3 different screens. The user may return to normal feeding screen from other screen by just pressing the enter key also. During operation, to stop the process, STOP key is pressed once. After pressing STOP key the system continues for a few more batches and then terminate the feeding process.


TO PAUSE : In the System weighing state, to stop the motor temporarily, PAUSE key is pressed once. In the paused state the system holds the previous information. To return back to the Weighing state, START key is pressed once.

HISTORY:
In System ready state or system running state to see the previous batch History, press HISTORY key once. The system holds the previous 64-batch history. In the History Screen, by pressing UP/DOWN key user can scroll the different batch History data. To see the detailed information of the same batch history, HISTORY key is pressed. To return to the System Ready State press ENTER key once. But in on line condition it will return to running state.

Online History: During running condition to see the batch history the following screen would be displayed.


If the History file has no data the corresponding message on the LCD Display will be as follows

To adjust the Feed Rate: To adjust the Feed Rate in the System Idle State as well as well as Weighing state the user have to unlock the Supervisory key first and then press SET RATE key once. The Feed Rate can be incremented or decremented by pressing f J. keys one by one and finally the ENTER key should be pressed to accept the set Feed Rate. After setting the Feed Rate the user have to lock the Supervisory Key.

During adjusting the set rate from the System Ready State the following message will be displayed on the LCD screen

Power Recovery Condition: If the Power cut occurs during system Weighing state then after power on the System will automatically go to Power Recovery state. In Power Recovery condition the system waits for the user command to either restart the previous Batch or refresh a new Batch. To restart the previous Batch the user has to press START key once. To terminate the previous Batch the user has to press STOP key once. During Power Recovery State the following message will be displayed on the LCD screen.

System Faults:
1. If the Fuse of the PSU Module has been blown out during operation then POWER ON LED at PSU Module will not glow. In this situation the fuse at the PSU module is to be checked and if necessary it should be changed with 5 amps glass fuse. During operation if the

Fuses at the Display Module has blown out then the System will show a Alarm Message as follows
2. In the System Running (motor moving) condition if there will be some problem in
sensing motor RPM with the Proximity arrangement at the Motor Pulley end then the
following Alarm Message will be displayed on the LCD Screen

3. In the System Running (motor moving) condition if there will be some problem in
sensing Drum RPM with the Proximity arrangement at the Discharged Drum end then the
following Alarm Message will be displayed on the LCD Screen

4. If the AC Drive for driving the AC Motor is found to be faulty during running condition
then the following message will be displayed on the LCD Display.

5. If the Tare Weight of the belt is less than 1 Kg. or greater than 6 Kg or equal to 0 Kg., then
the sensor might be erroneous. System will raise the alarm to alert the user. In this condition
the Sensor (Load cell) alignment is to be checked and the system is to be recalibrated. If the
problem still arises then the manufacturer is to be informed for thorough checking.


6. After pressing the START key the system will go to AUTO TARE ADJUSTMENT state. In this state the system will take the tare weight of the belt automatically. In this period the belt should be kept empty to take the weight of the belt alone. After adjustment the tare weight of the belt should be within +/- 500 gms of previously acknowledged Tare Weight. If Auto Tare Weight is beyond +/- 500 gms of previously acknowledged tare weight due to flow of material during the AUTO TARE ADJUSTMENT process or due to some sensor problem, then system will raise the alarm to alert the user and display the following message.

Advantages
The gravimetric weigh feeder equipped with load cell acting as microcontroller for the entire operation as described above offers a number of advantages, briefly as outlined below :
1. It ensures a constant rate of delivery of withered tea leaves with an accuracy level exceeding 95%.
2. The system totalizes the mass delivered on real time basis with accuracy better than 4-5%.
3. The system perform on-line display of total mass delivered (in kg), total time of operation, set rate and average feed rate.
4. The system has in-built self diagnostic Programme for ensuring better performance.
5. The system has well-defined calibration procedure for consistent operation and detailed event of individual batches.
6. The system has data storage for past 64 batches with date and total operation time along with built-in restoration of data in case of power failure.
7. High performance microcontroller is used for satisfactory performance of the system along with a large 40x LCD display for viewing different online operation.

8. The system uses total CMOS design for reduced power consumption.
9. The system includes online diagnostics for identification of errors and faults.
10. The system uses current loop for interfacing sensor signals giving better immunity to EMI.
11. The system uses high quality rugged components for long lasting under real-life factory conditions and employs modular construction for easy maintenance.
12. Option for audio annunciation, and computer interface for centralized monitoring of feeder operation, if desired and / or asked for.
As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should be understood that the above-descried features / examples are not limited by the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are intended to be embraced by the appended claims.

We claim :
1. A gravimetric weigh feeder equipped with microcontroller for feeding
vegetative matters at desired feed rate to Rotorvane for uniform maceration, thereby ensuring Quality enhancement, Energy saving and reduction in the maintenance cost of the machines, characterized in that the feeder comprises :
a) a main frame (1) carrying a tie (2) and side guard pillar post (3);
b) a conveyor belt (18) rotating on two rollers (14 and 15) with bearings (16 and 17) equipped with tensioning screw (11) and having a top cover sheet (19);
c) plurality of rollers (4,5 and 6) of which (4) is fixed idler roller, (5) is return idler roller and (6) is the swiveling idler roller housed in the swiveling idler roller arrangement (7), with a bracket (10) for return idler roller ;
d) a feeder equipped with leaf guide plate (22) having back and side guards (20,21,22,23 and 24) and a side guard extension discharge unit (25) ;

e) a drive means mounted on a suitable base (13) and
f) a controlling means (9) mounted on a base (8) for achieving controlled release of the vegetative matter for maceration or cutting.

2. A feeder as claimed in Claim 1, wherein the vegetative matter is tea.
3. A feeder as claimed in Claims 1 and 2, wherein the operation of the feeding unit is guided by the said controlling means which is a load cell (9) mounted on a load cell fixing base (8), said load cell being used for online weighting of tea leaves and meant for ensuring smooth operation of the system effecting a uniform feed rate of tea leaf and continuous recordal of the net weight of tea leaf processed in total operational time.

4. A feeder as claimed in Claims 1 to 4, wherein the drive means is a 0.37 KW geared motor operating at 1400 R. P. M. and 415 Volt ± 10% LP.
5. A feeder as claimed in Claims 1 to 4, wherein there is provided proximity switch fixing brackets on G. M. Side (27) as well as on side opposite thereto (28), bearing suitable guards (29 and 30).
6. A feeder as claimed in any one of the preceding claims, operation whereof is
controlled by means of a load cell (9) fixed on a base (8), a suitable block diagram of
which is depicted in Fig. 4 of the drawings accompanying this specification.
7. A gravimetric weigh feeder equipped with microcontroller for feeding
vegetative matters at desired feed rate to rotorvane for maceration, substantially as
herein before described with particular reference to the accompanying drawings and
the appended example.


d) a feeder equipped with leaf guide plate (22) having back and side guards (20,21,22,23 and 24) and a side guard extension discharge unit (25) ;
e) a drive means mounted on a suitable base (13) and
f) a controlling means (9) mounted on a base (8) for achieving controlled release of the vegetative matter for maceration or cutting.

Heretofore withered tea leaves after being plucked and treated were fed manually into rotorvane either by means of fixed speed conveyor or through withered leaf shifter, which could not maintain a uniform rate of feeding of tea leaves into rotorvane. Failure to maintain a uniform feed rate affected the quality of tea.
The present invention aims at overcoming the difficulties inherent in the conventional procedure for producing tea and provides A gravimetric weigh feeder equipped with microcontroller for feeding vegetative matters at desired feed rate to Rotorvane for uniform maceration, thereby ensuring Quality enhancement, Energy saving and reduction in the maintenance cost of the machines, characterized in that the feeder comprises :
a) a main frame (1) carrying a tie (2) and side guard pillar post (3);
b) a conveyor belt (18) rotating on two rollers (14 and 15) with bearings (16
and 17) equipped with tensioning screw (11) and having a top cover sheet (19)
c) plurality of rollers (4,5 and 6) of which (4) is fixed idler roller, (5) is
return idler roller and (6) is the swiveling idler roller housed in the swiveling
idler roller arrangement (7), with a bracket (10) for return idler roller ;

d) a feeder equipped with leaf guide plate (22) having back and side guards (20,21,22,23 and 24) and a side guard extension discharge unit (25) ;
e) a drive means mounted on a suitable base (13) and
a controlling means (9) mounted on a base (8) for achieving controlled release of the vegetative matter for maceration or cutting.