Adjustment Method Of Expansion Valve Of Air-cooled Box Chiller

By Author: monica
Total Articles: 10
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When the expansion valve is adjusted, it is necessary to rely on the adjustment rod to adjust the pressure of the spring, wherein the adjustment rod is turned inward to compress the spring, and turned outward to relax the spring. Rotate clockwise, the adjustment rod will be screwed in, otherwise, it will be screwed out.

During the operation of the refrigeration system, the adjustment direction and range of the expansion valve can be judged by the high and low values of the evaporation pressure. The evaporation pressure is higher than the set value, indicating that the flow rate of the expansion valve is too large, which should be adjusted appropriately (the adjustment rod needs to be rotated in a clockwise direction); the evaporation pressure is lower than the set value, indicating that the flow rate of the expansion valve is low , should be properly adjusted (that is, rotate the adjustment lever in a counterclockwise direction).

The expansion valve needs to be automatically adjusted within a specific range of operating conditions, and it also needs to be adjusted when the refrigeration system is being debugged. ...
... Once the expansion valve is functioning properly, it can be adjusted automatically.

When adjusting the expansion valve, a low-pressure pressure gauge can be installed on the suction pipe of the compressor, and the change of the suction pressure can be known through the change of the data on the pressure gauge.

If it is necessary to adjust the setting range of the expansion valve, it can be roughly divided into two steps. The coarse adjustment is performed when the operation starts, and the fine adjustment is required when the working temperature of the refrigeration system is close to the set value.

In the process of adjusting the expansion valve, it should be noted that the compressor will exhibit different physical phenomena under different operating conditions and ambient temperatures. In the case of high temperature, medium temperature and low temperature, the evaporation pressure of the compressor shows different frosting on the suction pipe. During debugging, the opening degree of the expansion valve should be adjusted according to the load.

The opening degree of the expansion valve is different, and the state of the superheat degree of the refrigerant at the suction end of the evaporator and the compressor is different. In general, superheat = return air temperature - evaporation temperature, where superheat refers to temperature difference, not temperature.

When reading the superheat, you need to grasp the timing, requiring stable high load and low load, temperature or pressure before shutdown and defrosting.

However, there is a delay in the transmission of the temperature sensing package. After each adjustment, the system should be allowed to run for a period of time, and at the same time, it is necessary to observe the changes in the suction pressure so that the direction of the next adjustment can be determined.

In a word, the adjustment of the expansion valve of the air-cooled box-type chiller is a relatively meticulous work, which requires the operator to have enough patience to do the adjustment work well.

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