Adjustment method of one machine multi-storage refrigeration system
Article overview: In some cold storage, one refrigeration unit is used to supply cold storage to several cold storages with different temperature at the same time.
In some cold storages, one refrigeration unit is used to supply cold capacity to several cold storages with different storage temperatures at the same time. Because the evaporation temperature of the evaporators of several banks is different, there should be different controls. For example, some refrigeration systems with one machine and multiple banks cannot directly control the refrigeration compressor circuit, but control the solenoid valves of each bank separately. When the library reaches the required temperature, the temperature controller of the library can cut off the power supply of the liquid supply solenoid valve circuit of this library and stop the liquid supply.
One machine multi-storage refrigeration system adopts the method of equipped with evaporative pressure regulating valve. In cold storage with high temperature and low temperature, the outlet pipe of the evaporator that needs to maintain a higher storage temperature is usually equipped with an evaporation pressure regulating valve to keep the pressure at the front of the valve at a given temperature. Within a certain range, after throttling through it, it is connected to a pipeline with a lower pressure in the return air pipe behind the valve, which ensures that the evaporators with different evaporation temperatures in the system work normally under different working conditions. This evaporative pressure regulating valve is also called a back pressure valve.
One refrigeration compressor cools the three cold storage rooms, and the evaporation temperature of the two high-temperature storage rooms is 2°C. The evaporation temperature of a cryogenic storage is -20°C. Install a back pressure valve on the return pipe of the high temperature library evaporator. In order to prevent the fluctuation of the high-temperature evaporation pressure from affecting the temperature of the low-temperature storage, a check valve is installed on the return pipe of the low-temperature storage evaporator to ensure that the high-pressure steam flowing out of the back pressure valve does not flow to the low-temperature evaporator during shutdown.
When debugging a refrigeration system with a back pressure valve, you should install a pressure gauge, unscrew the pressure gauge valve, and adjust the expansion valve and back pressure valve alternately. The back pressure increases when you adjust clockwise, and when you adjust counterclockwise, The pressure drops.
In refrigeration equipment, it is required to control the evaporating pressure for two purposes
First, make the evaporators working in different storage temperatures be able to operate under different evaporation pressures (that is, different evaporation temperatures). In order to achieve different evaporation temperatures and evaporation pressures of the three evaporators, it is necessary to operate in the high-temperature vegetable storage and The outlet of the evaporator of the dairy store) is equipped with a back pressure valve to keep the pressure before the valve at the required evaporation pressure. After the valve is throttled, the pressure after the valve is the same as the suction pressure, so that the pressure of each evaporator is reached. Work under the required evaporation pressure (evaporation temperature) to meet the requirements of refrigerated food for storage temperature.
Second, keep the evaporation pressure constant. Excessive evaporating pressure fluctuations will not only affect the operation of the device, but also affect the storage temperature control accuracy, causing deterioration of refrigerated items or increased dry consumption. Therefore, it is required to control the evaporating pressure to make it work constantly at a given evaporation On the pressure value.
