Grain Coolers for Cereals and Seeds

Grain Coolers for Cereals and Seeds

Working Principle

Principle of refrigeration system: The refrigeration system of grain cooler is similar to the principle of ordinary mechanical refrigeration equipment. Refrigeration compressor will be low-temperature and low-pressure refrigerant gas inhalation, compressed into high-temperature and high-pressure superheated gas discharged into the air-cooled condenser. In the condenser, the high temperature and high pressure refrigerant gas is cooled by the outside air, and becomes room temperature and high pressure saturated subcooled liquid. The liquid passes through the filter drier, sight glass, liquid supply solenoid valve, and then throttled into low temperature and low pressure liquid through the thermal expansion valve. Low-temperature and low-pressure liquid in the evaporator absorbs the heat of the outside air and becomes low-temperature and low-pressure gas, which is sucked in by the compressor and enters the next cycle.

Temperature and humidity regulation principle: centrifugal fan will filter the outside world high temperature air into the evaporator, through the heat exchange of air cooling, due to refrigeration, high temperature gas relative humidity will be increased with the lowering of the temperature, the relative humidity of the air after the evaporator can reach a high level. At this time, the wet and cold gas after the evaporator is heated through the rear heating device, so that the relative humidity is reduced to the preset value, and then the dry and cold air is introduced into the grain silo through the air supply pipeline and the air distributor, so as to realize the purpose of reducing the temperature of the stored grain and controlling the humidity of the stored grain and to achieve the effect of the grain storage at a low temperature.

Structural components

Refrigeration system: it mainly includes refrigeration compressor, air-cooled condenser, evaporator, filter drier, liquid-viewing mirror, liquid-supply solenoid valve, thermal expansion valve and other components, and the components work together to realize the circulation of refrigerant and heat transfer3.

Ventilation system: it usually consists of filter box, high-pressure centrifugal fan, air volume adjustment mechanism, air duct and so on. The outside air first enters the filter box for filtration and purification, is pressurized by the high-pressure centrifugal fan and adjusts the air volume through the air volume adjustment mechanism, and then is sent to the evaporator by the air duct to be cooled down and finally sent to the grain bin through the air duct.

Control system: it is the command center of grain cooling machine, control the evaporation temperature and air temperature of the machine through PID controller, PID controller through the temperature sensor installed after the evaporator and the temperature sensor installed at the exit of the grain cooling machine, respectively, measure the temperature of the grain cooling machine before the temperature, temperature after the temperature, and the set value of the PID controller is automatically compared to the air volume regulating mechanism to regulate the air volume and the opening degree of the heating regulating valve, to the grain cooling machine. The air flow is adjusted by the air flow regulating mechanism and the opening degree of the heating regulating valve, so as to control the working parameters of the grain cooling machine.

Characteristics

Advantages: it can effectively reduce the temperature of grain, delay the deterioration of grain quality, reduce the loss of dry matter, and maintain the nutritional quality and freshness of grain; it can control the humidity of stored grain, avoid the loss caused by condensation phenomenon in the barn, and prevent the grain from sprouting or gumming up and molding; it can reduce the loss caused by insect pests and molds, and reduce the contamination of fumigating agents on grain and the environment to realize the green storage; it can make the grain anti-frozen and fresh, prolong the grain's Preservation period, improve the value of rotating grain; for some mobile grain cooler, no need for each silo is equipped separately, can be flexible mobile use.

Limitations: relatively high energy consumption, large operating costs, which is one of the main reasons for limiting its wide application; high investment cost of equipment, the initial purchase and installation of grain coolers require a certain amount of capital investment; the use of the environment and operating technology has certain requirements, if not used properly, it may not be able to achieve the expected effect of cooling and storage of grain, but also may lead to equipment damage.

Application areas

Grain storage: widely used in all kinds of grain silos, such as shallow round silos, bungalow silos, etc. It can effectively reduce the temperature of grain, extend the storage period of grain, and ensure the quality and quantity of grain.

Grain processing: in grain drying, milling and other processing processes, the temperature of grain can be reduced to the appropriate level in a timely manner to ensure the stability and efficiency of the processing process and improve the quality of processing.

Agricultural production: it can be used for grain storage and transportation in farmland, as well as drying and preservation of crops, preventing corruption and deterioration of crops in the process of transportation and storage, and ensuring the quality and yield of crops.

Logistics and transportation industry: during the transportation of grain, it can effectively reduce the temperature of grain and maintain the quality and quantity of grain, thus ensuring the safety and transportation efficiency of grain.