Characteristics and treatment methods of ice block, dirty block and oil block in cold storage system

1 The characteristics and treatment methods of ice jam in cold storage system the characteristics of ice jam in cold storage system are: the compressor of refrigeration system works normally, but the refrigeration effect is poor, the high-pressure exhaust pressure is lower than the normal value, and the low-pressure return pressure is lower or even negative than the normal value When the refrigeration system is blocked by ice, the refrigerant can not be circulated, resulting in the temperature rise in the cold storage and the automatic defrosting phenomenon on the evaporator After the evaporator is clean, the refrigeration system returns to refrigeration Ice blockage of thermal expansion valve usually occurs at the orifice of expansion valve Its fault feature is that the refrigeration system starts to operate normally, but after a period of time, the evaporator begins to defrost After the defrosting process, the evaporator returns to the refrigeration state, and after a period of time, the defrosting phenomenon appears again The way to deal with the problem of ice blockage of thermal expansion valve is as follows: slight ice blockage of thermal expansion valve, The hot towel can be applied on the ice plug of the thermal expansion valve to remove the ice plug and resume the operation of the refrigeration system If the ice plug is serious and cannot resume the normal operation of the refrigeration system, the stop valves at both ends of the drying filter can be closed Remove the drying filter from the refrigeration system After replacing the desiccant in the drying filter, first open the stop valve at the liquid inlet of the drying filter Loosen the sodium at the inlet of the stop valve at the liquid outlet, tighten the stop valve at the liquid outlet of the drying filter after the gas runs out, so as to eliminate the fault and restore the normal operation of the refrigeration system 2 The characteristics and treatment methods of the dirty blockage in the cold storage system the characteristics of the dirty blockage in the cold storage system are: the compressor of the refrigeration system operates normally, but the evaporator does not frost, the high-pressure exhaust pressure is lower than the normal value, and the low-pressure return pressure is lower or even negative than the normal value After the refrigeration system is dirty and blocked, the refrigerant can not be circulated, causing the low-pressure protection action of high and low pressure relay, and the compressor stops When the machine is started manually again, the fault is still the typical dirty blocking fault The thermal expansion valve often appears dirty blockage, which is characterized by: when the inlet of the expansion valve is frosted (or the valve cover is also frosted), the temperature of the liquid inlet pipe is lower than the normal temperature, or even condensation The suction pressure of the compressor is lower than the corresponding normal pressure under the storage temperature, and the temperature in the cold storage drops slowly or does not drop, which indicates that the thermal expansion valve is dirty and blocked The way to deal with the problem is to close the stop valve from the liquid outlet valve of the refrigeration system to the evaporator Disassemble the liquid inlet of expansion valve, take out the filter screen and clean it with kerosene, and then replace it After replacing the desiccant in the drying filter, first open the stop valve at the liquid inlet of the drying filter, loosen the inlet sodium of the stop valve at the liquid outlet of the thermal expansion valve, and then screw it down after the gas runs out The stop valve at the liquid outlet of the expansion valve can eliminate the fault and restore the normal operation of the refrigeration system 3 Characteristics and treatment methods of oil blockage in cold storage system oil blockage in cold storage refrigeration system refers to the phenomenon that the valve hole of thermal expansion valve is blocked by solidified lubricating oil and hinders the flow of refrigerant Generally, it occurs in the refrigeration system of low-temperature cold storage, or it is caused by the high freezing point of low-quality refrigerant oil and low-quality refrigerant oil Because of the high freezing point of low-quality refrigerant oil, it may cause some lubricating oil to separate from the refrigerant and freeze into thick paste when it flows through the valve hole of thermal expansion valve due to the sudden drop of temperature, resulting in the valve hole of thermal expansion valve being blocked Plug In case of oil blockage in the refrigeration system, it is usually necessary to replace the refrigeration oil.