1、超市风幕柜制冷压缩机的排气温度。

　　超市风幕柜制冷压缩机的排气温度是指排气阀门处的制冷剂温度。为了保证压缩机的安全运行,规定R12装置的排气温度不能超过130℃,R22和氨的系统不能超过150℃。

　　排气温度过高,会引起润滑油因温度升高而降低粘度,使润滑效果变差,易造成运转部件损坏。当排气温度升高到接近润滑油的闪点时,不容易出危险，排气温度比冷凝温度要高得多。

　　2、超市风幕柜制冷压缩机的吸气温度。

　　超市风幕柜制冷压缩机的吸气温度是指吸入阀处的制冷剂的温度。为了保证压缩机的安全运转,防止液击冲缸现象。吸气温度要比蒸发温度高一点,也就是使制冷剂气体成为过热气体,有一定的过热度。一般情况下,在没有气液过冷器。

　　冷藏柜氟利昂系统里,吸气温度应比蒸发温度高5℃的吸气过热度是合适的。对于氨制冷装置,吸气过热度一般为5~10℃,吸气过热度过大或过小都应避免,若过热度过大,则会使制冷量下降,排气温度升高,耗功增大,若过热度过小,易产生液击冲缸现象。

　　冷藏柜在正常使用情况下，其压缩机的工作时间应短于停机时间。如果工作时间超过停机时间，则说明冷藏柜工作不正常。引起该故障的原因主要有以下两方面。

　　(1)制冷剂注入量不足，超市风幕柜长时间工作后蒸发器结霜不能化霜，箱内温度不能降低。此外制冷系统管路有泄漏，使循环系统内的制冷剂不足，也会出现上述现象,若在工艺管口接压力表检查，可发现压力低于正常值。

　　(2)压缩机使用日久，机械磨损大，工作时机壳温度高，高压排气管相对温度低，若在工艺管口接压力表检查，可发现低压值偏高。

　　(3)超市风幕柜冷冻室内结霜太厚，热阻大，影响冷气的传导。

　　(4)超市风幕柜放置不正确或冷凝器积灰太厚，从而影响冷凝器的散热。

　　(5)充注的制冷制过量，压缩机工作负荷重，冷凝器上边热、下边接近常温。制冷剂充入量过多造成在蒸发器内不能充分蒸发，致使蒸发器制冷量下降，若在工艺管口接压力表检查，可发现低压高于正常值。
 

　　1, the exhaust temperature of the refrigerating compressor of the supermarket wind curtain cabinet.

　　The exhaust temperature of the air curtain refrigerator compressor in the supermarket refers to the refrigerant temperature at the exhaust valve. In order to ensure the safe operation of the compressor, the exhaust temperature of the R12 device can not exceed 130 degrees C, and the system of R22 and ammonia can not exceed 150 degrees C.

　　The exorbitant exhaust temperature will cause the lubricating oil to reduce the viscosity due to the increase of temperature, make the lubrication effect worse, and cause the damage of the running parts easily. When the exhaust temperature rises to the flash point near the lubricating oil, it is not easy to go out of danger, and the exhaust temperature is much higher than that of the condensing temperature.

　　2, the air suction temperature of the refrigerating compressor of the supermarket wind curtain cabinet.

　　The suction temperature of the air curtain refrigerator compressor in the supermarket refers to the temperature of the refrigerant at the suction valve. In order to ensure the safe operation of the compressor, the liquid punching cylinder can be prevented. The suction temperature is a little higher than the evaporation temperature, that is, to make the refrigerant gas a superheated gas, with a certain degree of superheat. In general, there is no gas-liquid supercooling device.

　　In the Freon system of the refrigerator, the suction temperature is 5 degrees higher than that of the evaporation temperature. The ammonia refrigeration device, superheat is 5~10 DEG C, superheat is too large or too small should be avoided, if the superheat is too large, will cause a decrease in the refrigeration quantity, exhaust temperature, power consumption increases, if the superheat is too small, easy to produce liquid hammer cylinder phenomenon.

　　When the refrigerator is used normally, the working time of the compressor should be shorter than the shutdown time. If the working time exceeds the downtime, it is indicated that the refrigerated cabinet is not working properly. The main causes of the failure are the following two aspects.

　　(1) the quantity of refrigerant injection is insufficient, and the frost of the evaporator can not be frosted after a long time work of the supermarket wind curtain cabinet, and the temperature in the box can not be reduced. In addition, the leakage of the refrigeration system piping will make the refrigerant in the circulatory system insufficient. This phenomenon will also happen. If we check the pressure gauge on the technological orifice, we can find that the pressure is below the normal value.

　　(2) when the compressor is used for a long time, the mechanical wear is great, the temperature of the case is high and the relative temperature of the high-pressure exhaust pipe is low. If we check the pressure gauge with the technological orifice, we can see that the low pressure value is high.

　　(3) the frost of the supermarket air curtain freezer is too thick, and the heat resistance is large, which affects the conduction of the cold air.

　　(4) the air curtain cabinet in the supermarket is not properly placed or the condenser ash is too thick to affect the cooling of the condenser.

　　(5) overcharge of the refrigerating system, the compressor working load heavy, the condenser top hot and lower near the normal temperature. Too much refrigerant charge can not cause enough evaporation in the evaporator, resulting in the decrease of the refrigerating capacity of the evaporator. If we check the pressure gauge on the technological orifice, we can find that the low pressure is higher than the normal value.