This invention relates to what one calls, generally, a Rice Mill, and includes a system for processing harvested paddy grains to give them a desirable level of moisture and to prepare them for onward process of hulling (separating the husk / chaff from the grain) and further.

The control and fixing of the moisture content and dryness of paddy is an important step in the overall process as it decides the percentage of "broken ( i.e., broken or pulverized grains that occur as undesirables in the overall process ) which have a great say in the efficiency and thus the pricing and profitability of the system and process.

Before launching on the novel system by which we propose to accomplish this end, it is necessary, for cogency and contiguity of narration, to state briefly the process and broad form of the inventive field as follows

Harvested paddy grains, packed in bags generally of 50 kg each, are transported to centrally located rice mills (by trucks or other means).

After preliminary dusting and cleaning, the paddy is filled for soaking (A) into steel vessels of capacity up to 25 tonnes (up to 4 to 6 in number) and soaked to about 8 -10 hours in water; thereafter the soak water is drained off and the grains sent for steaming (B) ( also for loosening the husk from the grain ) for short intervals of up to 4 minutes.

Now the steamed paddy at a temperature of 70° c - 90° c, is put into a chamber C (typically of stainless steel) which is typically a wide sieve. This sieve receives the hot paddy on the upper side of a perforated plate, while cold atmospheric air blown from beneath the perforations cools it to about 50° c. The slight slope of the sieve pushes the grain to one end whence it is sent to the dryer at a moisture content about 40%.

This 40% moisture needs to be reduced to 9% or thereabouts disuniformity (i.e., fluctuation) of temperature due to fluctuations of pressure in the boiler causes up to 5% of" broken " (broken grains in paddy stage) this being a higher loss percentage as such can only the secondary output and not rice grains. This also results in higher steam consumption, caused by lack of close monitoring due to manual control of temperature into the drying chamber.

Another difficulty is the need for provision of exact or precise pressure and temperature control in manual operations across the rice mill. A further difficulty lies in extracting the hot water from the heat exchanger very frequently, i.e., for an duration 30 sees, every 10 to 15 minutes interval.

The operations of shutting off steam and hot air blower during cooling mode, i.e., every hour or two, form another burdensome sequence of man power effort.

Summing up the irksome problem listed above in day to day rice mill operations, we have been able to present novel features and operational sequences into such a typical rice mill, such as can mitigate these inaccurate, cumbersome and loss causing stages.

To assist the description and to enable the reader understand the some more in more lucid manner, we seek to refer to schematic diagrams showing the flow of operation and of the equipment involved, wherein

Fig. 1 shows the system limited to manual operation, and

Fig. 2 shows the system with the inventive control added on.

Figures a, b, shows respectively the schematic working in auto mode and manual mode respectively.

To this end, we propose herewith novel control means and features into the above discussed typical rice mill, as will be detailed herein after.

These are electrical power based and perform via embedded c programming system: it can also be achieved, alternatively by "PLC" (Programmable Logic Controller - Microchip combination) and other such program devices generally known per se and are to be deemed as included in this invention.

Basically the rice mill performance control lies in two principal factors.

Briefly the paddy is fed in the 40% moisture state into the dryers of standard capacity varying as widely as from 16 to 40 tones paddy per load. This loading is done via an elevator 6 which has a series of cups 6a fixed on a bottom roller 6a, 6b respectively. Paddy from the cooler is fed at the bottom thereof and goes via the cups to be unloaded at the top into the top of dryer to its fill.

Once the dryer is full the following steps are effected in sequence:
a. The cooler gate is closed,
b. The dryer gate is opened ( at its bottom)
c. The blower is put on, the elevator,
d. Thus causing paddy from the feed rollers to fall down and onto the elevator bottom, and on again to dryer top.

Heat is given via the heat exchanger by hot air (heated by steam therein) the steam in turn being fed from the boiler.

At present the control of the heat input and output in the system is accomplished by manual means.

We now go on to the inventive improvements effected on this system to automatic and improve its efficiency and working.

This has necessitated
1. Apistonisedvalve2.
2. A motor operator valve 3.
3. Limit switches in the motorized valve 3 a, 3b ( or proximity sensors )
4. Temperature sensors 10.
5. A control panel 7 having an LCD display, a drive unit, a key pad, and a central relay board, having essential circuit elements.
6. A pneumatically operated drop valve 9 to remove condensed steam.

An important feature in this invention is that in existing rice mills, the heating and cooling processes are controlled at intervals manually, subjecting it to the irregularities and vagaries of manual operators. To overcome this shortcoming, We propose to include in the whole system, a piston valve and motor operated valve.

These two valves are preferably fitted in the steam line from the boiler to heat exchanger, but preferably within, say, a meter distant of the heat exchanger to preclude -loss of steam heat.

The piston valve is preferably operated by a solenoid i.e., electric power, and is closed fully:

a. Only when the temperature of the working steam or hot air exceeds the maximum set temperature difference during the heating phase or mode.

b. Only to suddenly close the steam inlet for transition from heating mode to cooling mode.

c. In event of power cut, to shut off the steam to terminate operations.

This piston valve is preferably located at the steam inlet of the heat exchanger.

This valve receives its control order from the automated control panel of this invention

The motor operated steam valve is controlled from the same control panel and effects five adjustment of heat steam flow into the heat exchanger to closely govern its temperature preferably by an AC synchronous motor, or AC stepper motor, though however any type of bidirectional motor may be employed.

In a preferred embodiment a gear and pinion or a step down gear system of other known combination may used. This gear is designed and adopted to regulate steam flow in accordance with heat requirement and receives its command ( control) signal from the control panel which works on temperature inputs from the hot air of the heat exchanger.

The drop valve, whose purpose is to tap out condensate water steam mixture from the heat exchanger exit, is accordingly located at the outlet pipe thereof and is set to operate at predetermined intervals ( may 5 to 20 minutes ) for durations up to 10 – 20 seconds, this heat may be fed back into boiler feed water. The drop valve is also preferably operated at start up and shutdown for predetermined intervals.

The existing master control panel has a set each of on-push buttons and off-push buttons each consisting of contactors, timers and overload relays, these are individually operated manually and controls the several points of null operation namely, elevator motor, blower motor, dryer motor in each dual mode i.e., manually on or off.

The control apparatus of this invention is in a way, an add-on system that is attached to the above manual system thus making it automatic while at the same time retaining the option of manual operations at will.

A microcontroller located inter alia as 7 in fig. 2, drives the elements 2, 3,8 and 9, in turn the existing master controller 8 controls dryer 5, elevator 6 and blower 4. Getting back to the microcontroller, this microcontroller 7, according to its embedded C program loaded (i.e., programmed ) the temperature signal from the temperature sensor sets the working into tune as required for the process. This sequence lasts all through the heat-up process and is controlled by the motorized valve 3. If the heat (i.e., temperature) rises beyond the limit set for the piston valve, the controller 7 shuts off the piston valve.

In the auto mode of operation of the controller 7, it gives drive signals to the existing master control panel 8 and blower 4 and runs the elevator 6 and dryer 5. Moreover if the temperature of hot air from the heat exchanger dips below the set temperature ( say, 50° c ) the blower gets shut down (i.e., off) and the alarm siren is set on. If the temperature of the hot air dips below the set temperature, the controller automatically sends a signal to the AC motor located on the motor valve 3 and sets it on, which in turn opens the valve to increase steam into the heat exchanger 11.

The closing of this valve is a reverse operation to the above and occurs when heat input into the dryer is more than the set temperature.

Reversely, if the heat input into the dryer is greater than is needed for sustaining the set temperature, this valve is subjected to a closing operation till the set temperature conditions are restored.

In the manual control mode of the controller (panel) the control signal from the same, goes only to the elements 2, 3 and 9, te., piston valve, motor valve and the drop valve, this effectively means that the same function is provided as in the auto function, that is, in this mode the elevator 6, dryer 5 and blower 4 are to be operated only manually.

Other extra safety features are incorporated in the control devices:

For example, if the hot air temperature of the dryer does not attain set level, even after allotted time, the siren starts and keeps screaming till attended.

At the end of the heating part of the cycle for a paddy batch or lot, when over, and the cooling cycle is to start, this controller of the invention automatically puts off the steam supply the blower: the elevator and feed roller, however, continue to operate.

Another important novel feature of this invention is the inclusion and use of a so called moisture (content testing) meter to determine and regulate thereby, the moisture percentage present in the paddy existing from the dryer outlet channel, which latter is literally (in the preset preferred embodiment) shaped as a rectangular section open at the top and lying at an incline, from the dryer bottom.

The moisture meter is set such that in operation it takes sample readings every say 15 minutes and feeds this data to the automated control panel: in accordance with the functions and condition set therein the system starts striving for achieving these desired operational parameters.

The system is programmed to run by itself to the exclusion of the moisture meter, with input of mere heating and cooling steps - only, this would be a crude way of doing it.

In a preferred embodiment, the moisture water is set across the opposite lateral faces of a rectangular box located beneath an opening on the outlet channel floor. A closure plate, located over this opening, may be drawn out from its closing position to enable a requisite quality of grain to fill the box beneath. The plates or terminals of the moisture meter are located across the opposite vertical faces of the box: once it is filled with grain, the moisture content of the impounded grain is easily measured on the meter. The remnant grain may be discarded from its box by drawing out another operable closure plate there beneath, post- measurement- preparatory to a fresh batch and measurement.

The control panel may as an example be programmed to sense the moisture level of the paddy (by above narrated means) and includes the facility of control via manual settings separately for both temperature and moisture and accordingly regulate the temperature including the cooling mode.

These features, understood by persons in the art are to be deemed as included within the scope of the invention and are sought to be not elevated here further. Other features, like elevator and speed sensor to restrict its speed to desirable or set level, are also possible and are to be deemed as part of the invention.

This invention, as is evident from the above description of a preferred embodiment, affords full fledge quality, performance and operation controls of a standard rice mill of today including its day to day operations and parameters. These measures 'are designed to the simple in operation, economical in cost and maintenance, accurate in effect, and reliable in performance. Moreover as will be clear to persons of ordinary knowledge in the art, other variations and further embodiments as well as digressional features are possible within the scope of the invention without deviating from the novel features thereof.

THE CLAIMS

1. For a grain processing mill which prepares paddy for hulling, comprising the processes of soaking in water, steaming followed by drying and cooling, said mill having a steam producing boiler,

a heat exchanger into which steam and air are fed for transmitting heat into the air for heating the grain.

a grain dryer having an inlet and an outlet for grain and an inlet and an outlet for hot air passage,

a grain feed device for feeding grain in and out thereof, steam input control means for the heat exchanger, steam inlet and cutoff means for the heat exchanger for the whole process, sensor means for discerning the temperature of the hot air, means for changing extreme limit conditions for the steam only into heat exchanger from one to the others, means for sensing and regulating the moisture content of the exit grain, and centrally located control panel cum indicating means for receiving the overall operations.

2. The grain processing mill as claimed in claim 1, wherein a blower is for blowing air into the dryer.

3. The grain processing mill as claimed in claim 1, wherein the heat exchanger is a steam -to-air exchanger with a blower to push in air and pipes for inletting hot steam.

4. The grain processing mill as claimed in claim 1, wherein the grain dryer is a vertical based with a conical base, having drop barricades of horizontal channels down which the grains are powed from the top.

5. The grain processing mill as claimed in claim 1, wherein the dryer exit is an inclined open channel for the grain to descend.

6. The grain processing mill as claimed in claim 1 ,wherein the grain feed device is are that elevator receives grain from the channel bottom to ascend upwards and on to the dryer top.

7. The grain processing mill as claimed in claim 5, wherein the elevator has cup shaped carrier elements and runs between top and bottom wheels located to deliver grain into the dryer top via a feed Channel a top thereof.

8. The grain processing mill as claimed in claim 1, wherein the steam input control means is a control valve having an input port and an output port, a closure member retractably held across the passage that connects said ports to open or shut the same against steam passage in gradual stages, to allow steam in regulatable quantities there through.

9. The grain processing mill as claimed in claim 8, wherein said closure member is connected by a limb on to a drive means to operate said member in required degrees.

10. The grain processing mill as claimed in claim 8, wherein said drive means is a motor driven by control signals from temperature signals from the hot air of dryer input.

11. The grain processing mill as claimed in claim 1, wherein said steam inlet and cut off means for the heat exchanger is a piston valve having an inlet and outlet ports, connecting a passage that is fully operable or fully closable by a piston controlled by signals to fully start or fully shutdown the whole operation.

12. The grain processing mill as claimed in claim 11, wherein the piston is closable by signals indicative of extreme conditions in excess of heat settings.

13. The grain processing mill as claimed in claim 1, wherein the moisture content indicating and sensing means is located at the limb or channel of the dryer.

14. The grain processing mill as claimed in claim 13, wherein the sensing means is located beneath a closable vent in the exit channel wherein falling grain in collectable in a cup tray to enable measurements of the moisture content of the same.

15. The grain processing mill as claimed in claim 14, wherein the various control devices are located in a control panel and are operable both by manual settings or auto setting.

16. The grain processing mill as claimed in claim 15, wherein the manual mode controls operate only the piston valve and the motor valve .

17. The grain processing mill as claimed in claim 15, wherein the auto mode function control, separately, the elevator, dryer feed roller, piston valve, motor valve, blower.

18. The grain processing mill as claimed in claim 15, wherein the moisture, content control function is included in the manual and auto modes.

19. The grain processing mill which prepares paddy for hulling; substantially as described with reference to the accompanying drawings.

20. A control system for the running of a grain processing mill, substantially as herein described and illustrated with reference to the accompanying drawings.

21. A rice mill using the automatic control system as described, claimed and as illustrated.

22. A paddy dryer for a rice mill automatic control system as described and as illustrated.