Research On The Equipment And The Control System For Browned Rice Germinating

Brown rice is a kind of rice with the whole grain, and can be got from rice after it is husked. It has a poor taste and cooks time-consuming for retaining the cortex, aleurone layer and germ. But compared to refined rice it is more nutritious. The study showed that germinated brown rice can be got from brown rice after it is cultivated and then germinates under certain conditions. Germinated brown rice is composed by the germ and endosperm. It has a higher nutritional value. The brown rice is easy to cooking, has a better taste, is easier to digest and accepted for the fibers of the bran layer of brown rice are softened after brown rice germinated. Therefore, it has important research significance and practical application value for promoting the development of the deep processing technology and equipment of rice and improving the added value and nutritional value of rice products to study and develop the equipment for brown rice germinating and achieve the industrialized production of germinated brown rice.Based on the existing research on germination process of brown rice, this paper has researched and developed a kind of machining system for germinated brown rice by applying the design and manufacture and control technology of modern equipment. The main contents include:1. A jacketed type of brown rice germinating system with a stirring device has been designed and developed according to process requirements of brown rice germinating. It can produce2000kg germinate brown rice each batch. The system structure is mainly composed of a vertical germination tank, a hot water circulation device, a ventilation, a stirring device, a spray system and a discharging device etc. The germination tank adopts vertical jacket structure. Brown rice is placed in the tank. The jacket is passed into hot water to ensure that the germination temperature of brown rice in the germination tank is in a constant temperature range. The stirring device is a vertical screw mixer and is droved by a motor. The tank is heated evenly by stirring brown rice regularly. The ventilation device is mainly composed of a blower and a ventiduct placed in the germination tank. It can supply the tank with oxygen for brown rice germinating through the blower work regularly. The hot water circulation device is composed of a water storage tank, a circulating pump, a electric heater and a temperature sensor; its main function is providing circulating hot water for the germination tank in order to maintain the germination temperature in the tank and providing40℃and85℃process water respectively for brown rice soaking processing and destroying enzyme at the same time.2. A control system of brown rice germinating system has been designed and developed according to requirements of the process of brown rice germinating and some technical parameters. It can control a total of10actuator, including the blower, motors, water pump, switches solenoid valves, flow control valves and electric heater or steam valve etc. Its hardware part is mainly composed of PLC, touch screen, temperature sensors and a variety of solenoid valves etc. The PLC used CPU224XP with relay output type which belongs to Siemens S7-200series. The touch screen used Smart700IE which can provide the standard functions of human-machine interface. The temperature in the germination tank and that of the circulating water can be collected by a temperature sensor and then fed back to the PLC in real-time. The system control program was writed according to the process requirements and the functions to be achieved. The program is divided into two parts, including the main program and subroutine. The main program mainly achieved to assign the process parameters, select automatic operation or manual operation, pause, end, and read the analog input signal, etc. The subroutines mainly complete the specific functions of automatic control, manual control, system initialization, cleaning, soaking, germination and destroy enzymes.3. According to the existing processing technology for brown rice germinating, the germination test of brown rice has been done by using the incubator in the laboratory first. By orthogonal experimental design and analysis, the optimum combination of the four key process parameters for brown rice germinating was determined. It is that the soaking temperature is30℃, the soaking time is18h, the germination temperature is35℃and the germination time is24h. Under the4groups of better process conditions which were selected, the average germination of brown rice was about78%. At the same time, the verification testing for brown rice germinating was done in the germination system for brown rice. The test results showed that under the selected test conditions, the average germination rate of brown rice was about70%.The study showed that through using a jacketed structure with a stirring device, hot water circulation to thermal insulation and a shower nozzle to preserve moisture; the brown rice germinating system can make the temperature and humidity in the tank evenly distributed and meet process requirements of brown rice for the temperature, humidity and oxygen content. The system can control the whole processes besides feeding and discharging for producing germinated brown rice automatically and realize the automated production of germinated brown rice.