How to ensure efficient and stable operation of refrigerators? Two common problems to be solved

2024-01-12

In recent years, with the rapid development of the ice making industry, cold chain logistics industry, and food refrigeration industry, the market size of China's freezer industry has been expanding year by year and has been applied in ice making, food refrigeration, industrial production processes, air conditioning, and other fields. However, some users have also reported that refrigerators often encounter some problems during use, such as deterioration of the refrigeration oil and a decrease in temperature difference between the refrigerators.

A refrigerator mainly refers to a mechanical equipment that uses a compressor to change the pressure change of the refrigerant gas to achieve low-temperature refrigeration. However, due to the different operating conditions and working media of the compressor used, it is different from a general air compressor. There are two types of refrigerators: water-cooled and air-cooled. The water-cooled type has better refrigeration effect, but the air-cooled type is flexible and convenient, without the need for cooling water, and can be used in areas with water shortage or mobile occasions. Undoubtedly, refrigerators may encounter problems such as spoiled refrigeration oil and reduced temperature difference during use.

From the perspective of deterioration of refrigeration engine oil, there are usually four reasons, such as oil-water mixing, impurities mixing, high-temperature oxidation, and inconsistent oil grade. Specifically, the refrigeration engine oil was originally pure oil, but due to certain reasons, water mixed into the oil not only reduces the viscosity of the oil, but also causes a decrease in the lubrication performance of the compressor. If casting sand and metal debris are mixed into the engine oil, it may lead to a decrease in the quality of the refrigeration oil. Similarly, low-quality sealing gaskets and rubber rings may also increase the aging and deterioration of the refrigeration oil.

In addition, if the exhaust temperature of the air compressor is high, the low-temperature oil will oxidize at high temperatures, which will reduce the viscosity of the lubricating oil, affect lubrication performance, and may also cause oil oxidation and deterioration. Especially for refrigeration oil with poor thermal stability, free carbon decomposes around the valve plate in high temperature environments, causing the valve plate to not close tightly, thereby reducing the output coefficient of the compressor. Also, be careful not to use engine oil with different oil grades. Mixing different oil grades can cause a decrease in the quality of the refrigeration oil.

For a cooler with a smaller temperature difference, the reasons may be blockage of the evaporator, damage or blockage of the expansion valve, refrigerant leakage, filter blockage, blockage of the return air network, excessive water flow, compressor damage, and so on. Firstly, excessive viscosity of chilled water, insufficient cleanliness of chilled water, and the formation of crystals in the chilled water can all cause evaporator blockage. In this case, it can be determined by observing the return air area of the compressor, that is, when a large area of ice formation occurs at the return air port of the compressor, evaporator blockage may occur.

Secondly, if external conditions cause physical damage, self damage to machine components, or a decrease in system cleanliness may cause damage or blockage to the expansion valve, it can be determined by listening to the sound of the liquid inlet pipe and whether the rear of the expansion valve is frozen. Once again, physical damage caused by external conditions, self damage to machine components, and decreased system cleanliness can lead to clogging of the filter. It is necessary to determine whether there is a temperature difference in the refrigerant passing through the filter.

Finally, the decrease in system cleanliness and deterioration of refrigeration oil may lead to blockage of the return air network, which can be determined by the temperature difference in the return air pipe, the temperature difference of the compressor body, and the discharge temperature of the compressor. If the water flow rate is too high, it can be judged by observing the water pressure difference between the inlet and outlet of the evaporator, as well as the operating current of the water pump. If the compressor is damaged, it may be due to electrical damage, prolonged use, harsh operating environment, or internal faults of the compressor. Therefore, it is necessary to promptly identify and solve the cause to ensure the efficient and stable operation of the refrigerator.

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