Cold storage defrosting methods are as follows:
1. Mechanical defrosting: It is mainly necessary to use a broom to button the frost or scoop the frost with a special scraper. This method is suitable for smooth wall pipes and top pipes, but it is difficult to remove all the frost on the row pipes.
2. Hot ammonia vapor flushing frost: the principle of its action is to introduce hot ammonia vapor into the cooling tube, so that the frost layer outside the wall heat exchange, forcing the frost layer to absorb heat and melt from the exhaust surface, so as to achieve the purpose of defrost. In order to shorten the defrosting time and improve the defrosting efficiency, the defrosting hot ammonia is generally drawn from the exhaust pipe of the single-stage compressor, because the exhaust temperature of the single-stage compressor is higher, which is beneficial to the defrosting. In order to reduce the amount of oil entrainment in hot ammonia, hot ammonia for flushing should first pass through the oil separator and then connect to the frost flushing pipeline.
3. Water defrosting: The use of hot ammonia defrosting has a much better effect than mechanical defrosting, but for dry chiller installed in the freezing room, cooling room and cold storage room, the energy loss is larger during defrosting, and the operation is more complicated and inconvenient. Therefore, in recent years, dry chillers have generally increased water flushing frost pipelines. Water defrosting is defrosting by using water flow of a certain pressure to directly scour the frost layer outside the chiller pipe. According to the test, if the defrosting water pressure is maintained at 1.5-2 kg\/cm, the defrosting can be completed in 20 minutes, and the water volume of the cooling pipe per square meter is between.035 and.05 meters. With edema cream not only the effect is good, but also the operation is simple, easy to achieve automatic control operation, its operating procedures are as follows: Close the supply valve and return valve of the chiller, and remove the block of the chiller drain port. ②. Start the frost flushing pump and open the frost flushing water valve. Note that when the pressure in the exhaust pipe of the chiller exceeds 8 kg\/cm, open the return air valve to reduce the pressure. ③. After the frost is planted, close the water steal valve, stop the pump, put on the drainage port, open the frost water to empty the water valve, and put the water in the memory to avoid freezing.
4, when the water on the cooling pipe is exhausted, the fan is opened first, and the water film attached to the surface of the pipe is blown away. Then slowly open the return air valve, and when the pressure in the exhaust pipe is equal to the return air pressure, open the liquid supply valve and resume normal work.
Shutdown defrost
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That is, stop the operation of the compressor, open the door of the warehouse, let the temperature rise, wait for the frost layer to automatically melt, and then restart the compressor.
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defrosting
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After the goods in the warehouse are moved out, wash the surface of the evaporator row pipe directly with high temperature tap water, so that the frost layer melts or falls off. In addition to too thick frost will lead to poor heat transfer effect of the evaporator, the evaporator surface due to long-term cleaning and dust accumulation is too thick, its heat transfer efficiency will also be significantly reduced.