The Structure and Classification of Grain Cooler

Grain cooler mainly consists of three parts: refrigeration system, moisture control system, air supply system. The major components are ventilator, air filter, compressor, condensing valve, evaporator, expansion valve, Heating device, control cabinet, mobile frame and safety guard, etc.

(1). Cooler System: it is consisted of compressor, condensing machine, evaporator, expansion valve. The refrigeration compressor inhaled the low temperature and low pressure refrigerant and compressed into the high temperature and high pressure superheated gas, discharged into the air-cooled condenser, In the condenser is cooled by outside air to room temperature and pressure saturated supercooled liquids, through drying and filtering device, visual liquid lens，liquid supply electromagnetic fluid, through thermostatic expansion valve throttle to low temperature and low pressure liquid, In the evaporator, the heat absorbed by the outside air becomes low temperature and low pressure gas and is inhaled by the compressor and enter the next cycle. The refrigerating output of refrigeration compressor is can be adjusted. According to the requirements of grain cooling machine humiture, in the certain evaporating temperature, can change hot-gas heat control valve opening degree， a part of high temperature pressing is sent to the heating coiler, increase the output temperature to realize different output humiture.

(2). The air supply system is consisted of compressor, ventilator, plenum chamber, etc. The outside air into filter box to filter and purify, through the high pressure centrifugal fan pressurized and air regulation machine to adjust air quantity, then through the air passage sent to the evaporator and be cooled, become the cold air near-saturation, after the heating plate heated and cooled, the cold air reach to the temperature and humidity required by the process, the air channel enters the grain silo finally.

(3). Control system: It is consisted of electric cabinet, programmable controller, inverter, sensor, actuator, etc. The control system is the control center of whole grain cooler, which control the evaporating temperature and output temperature of machine through the PID controller. The PID controller through the temperature sensor installed in the evaporator and the temperature sensor arranged at the grain cooler machine,

(4).  Respectively measure the pre-temperature and back temperature of grain cooler. Compared with the set value of PID controller automatically, control the operational parameter of grain cooler according to air regulation mechanism adjust air quantity and heat control valve opening degree. The control system also has perfect defencive function to ensure the safe handling of grain cooler machine.

Classification:

The grain cooler is divided into two types according to the structure: preposition type and postposition type. The preposition grain cooler refers to the fan before the evaporator; the postposition grain cooler refers to the fan after the evaporator.

Grain coolers are divided into large, medium and small sizes according to refrigerating capacity. The refrigeration capacity more than 80KW is the large machine; 50~80 KW is  medium-size machine， below 50KW is minimal machine.