The expansion valve is one of the four components of the programmable high and low temperature damp heat test chamber refrigeration system. It is an important device for regulating and controlling the flow and pressure of the refrigerant into the evaporator, and is also the “demarcation line†on the high and low pressure sides. Its regulation is not only related to the normal operation of the whole programmable high and low temperature damp heat test chamber refrigeration system, but also an important indicator to measure the technical level of the operator. Adjusting the expansion valve must be carried out carefully and patiently. The adjustment pressure must be boiled (evaporated) by the evaporator, and then passed through the pipeline into the compressor suction chamber and reflected on the pressure gauge. It takes a time. Each time the expansion valve is mobilized, it usually takes 10-15 minutes to stabilize the adjustment pressure of the expansion valve on the suction pressure gauge. The suction pressure of the programmable high and low temperature damp heat test chamber compressor is an important reference parameter for adjusting the pressure of the expansion valve. The opening degree of the expansion valve is small, the flow rate of the refrigerant is small, and the pressure is low; the opening degree of the expansion valve is large, the flow rate of the refrigerant is high, and the pressure is high. Depending on the thermal properties of the refrigerant, the lower the pressure, the lower the corresponding temperature; the higher the pressure, the higher the corresponding temperature. According to this law, if the outlet pressure of the expansion valve is too low, the corresponding evaporation pressure and temperature are too low. However, due to the decrease in the flow rate into the evaporator, the pressure is reduced, the evaporation rate is slowed down, the cooling capacity per unit volume (time) is decreased, and the cooling efficiency is lowered. In order to reduce the pressure and temperature loss after the expansion valve is adjusted, the expansion valve should be installed on the horizontal pipe at the inlet as much as possible, and the temperature sensing package should be wrapped in the center of the side of the return pipe (low pressure pipe). When the expansion valve is in normal operation, the valve body is frosted and the inlet side should not be frosted. Otherwise, it should be considered as ice block or dirty blockage on the inlet filter. Under normal circumstances, the expansion valve works very quietly. If a clear "filament" sound is emitted, the refrigerant in the system is insufficient. When the expansion valve has a fault in the temperature sensing system, such as air leakage or adjustment failure, it should be replaced. This article is from Beijing Yashilin Test Equipment Co., Ltd. Reprint, please indicate the source Garden Supply Store,Indoor Gardening Supplies,Landscape Supplies,Magic Garden Supplies Changzhou Satidi Import and Export Co., Ltd. , https://www.guanjiejt.com
Operational adjustment of expansion valve in programmable high and low temperature damp heat test chamber refrigeration system