The refrigeration device is prone to failure and the reason

The refrigeration device is prone to failure and the reason

Among the failures of refrigeration equipment, failures caused by "leakage" and "blocking" are the most common.

　　 1. Leakage of refrigerant

　　Especially fluorine refrigerants have strong permeability, and leaks will occur if they are not tight. Insufficient refrigerant and decreased cooling capacity: air often penetrates into the low-pressure part of the device, causing the high pressure to rise, the compressor power consumption increases, and the cooling capacity decreases. For this reason, not only the installation must be strict, but also the operation management must be checked frequently, and if any leakage is found, it will be eliminated in time.

　　 2. Dirty blockage and ice blockage

　　 Expansion valve is a common place for ice blockage. Because the refrigerant contains moisture, when the refrigerant passes through the expansion valve, the water will be analyzed and formed into ice particles when the refrigerant passes through the expansion valve. After the ice jam, the refrigerant flow decreases sharply, so the cooling capacity decreases, the frost layer of the evaporator and the air return pipe is soft, and the storage temperature cannot drop.

　　 Dirty blockage is a blockage caused by dirt, which mostly occurs in dryers, filters, expansion valve inlet filters, etc., and sometimes also occurs on pipeline valves.

　　 In addition, in the low temperature equipment below -60℃, oil blockage will occur on the valve hole of the expansion valve. This is due to the use of lubricating oil with excessively high solidification electricity. When the lubricating oil dissolved in the freon refrigerant is analyzed by the low temperature part after being throttled by the valve hole, it becomes a paste and sticks to the valve plate to cause blockage.

　　 Three, the problems that are prone to refrigeration equipment

　　 1. When the exhaust pressure rises and exceeds the allowable value, the pressure relay automatically cuts off the power supply, and the compressor performs a protective stop. The main reason for the high pressure rise is: there is air in the device. Air cannot be condensed into liquid at room temperature, so air is stored in the condenser. As a result, the heat transfer effect of the condenser will be weakened, causing both the condensation temperature and the condensation pressure to rise. At the same time, the air itself has a certain partial pressure, and the exhaust pressure should be the sum of the condensing pressure and the air partial pressure. Combining these two factors, the exhaust pressure will increase and the exhaust temperature will also increase. If you touch the exhaust pipe and cylinder head with your hands, it will be very hot.

#There is air in the device. Check how the air enters the system before discharging the air. The reasons for the air entering the device are as follows: First, there are leakage points in the low-pressure section, especially in the low-temperature refrigeration device. The suction pressure is lower than the atmospheric pressure. Once there is a seepage point in the low-pressure section, air will penetrate the device. The most leaky places are the shaft seal and pipe joints. If a leak is found, it should be eliminated in time. Second, before adding refrigerant, the air in the device is exhausted clean, or when adding refrigerant (or adding lubricating oil). The operation is not rigorous and air infiltrates the system.

　　# The cooling water volume (or air volume) is insufficient or the water volume regulating valve fails. If the amount of cooling water (or air volume) is insufficient, the heat taken away by the cooling water (or wind) will decrease, which will increase the temperature of condensation and increase the exhaust pressure. The reasons for the insufficient cooling water volume are: the opening of the cooling water inlet valve is too small; or the water pressure is too low (generally should be above 0.1Mpa): or the inlet pipe is blocked: or the water volume regulating valve fails, etc. To judge this point, the temperature difference between the cooling water in and out can be measured during the operation of the refrigeration device. Under normal conditions, the temperature difference is generally between 2 and 4℃. If the temperature exceeds this value, the cooling water quantity can be judged to be insufficient, because as the cooling water quantity decreases, the water flowing time in the condenser increases, and the temperature difference between the inlet and outlet water is large. .

　　 In the cooling refrigeration device, because the fan is not turned on, the ambient temperature is too high (above 40°C), and the heat dissipation efficiency of the condenser is very low, which will cause the pressure to rise significantly. In this case, even if there is no pressure relay, the motor will be overloaded and the thermoelectric device will act and the power will be cut off.

　　 In a refrigeration device equipped with a water volume control valve, if the water pressure of the water source is sufficient but the cooling water supply of the condenser is insufficient, at this time, the water volume control valve should be checked for problems.

　　# The condenser has scale. With scale, the thermal resistance increases, and the heat transfer effect is greatly reduced, causing the condensation temperature to rise and the exhaust pressure to rise accordingly.

　　# Too much refrigerant. The amount of refrigerant added to the refrigeration device is too much, and as a result, the excess refrigerant occupies a part of the condenser's volume, which reduces the heat transfer area of the condenser, thereby causing a high pressure increase.

　　# The exhaust pipe is not unblocked or the inlet filter of the oil separator is blocked.

　　 2. When the low pressure (ie suction pressure) is too low and lower than the allowable value, the pressure relay will automatically cut off the power supply and stop the machine for protection.

　　3. The oil pressure is too low and the oil supply pressure is lower than the set value. As a result, the oil pressure relay will act and cut off the power to stop.

　　4. The motor is overloaded, causing the thermal relay to operate, or the fuse is blown, and the power supply is cut off and the vehicle stops.