目前全国大部份地区10吨～50吨的小型冷库,凡是采用氟利昂作制冷剂的蒸发盘管一般没有除霜措施,只能人工扫霜。而人工扫霜既浪费人力,又不安全,况且除霜不彻底,影响冷冻机的制冷效率。根据有关资料介绍,当蒸发盘管霜层厚度达到2毫米,产冷量仅达其初值的70％(见《冷藏技术》1986年第1期38页)。可是有的冷库盘管上霜层厚度竟达5～6毫米,所以造成速冻室冷冻品不能按时出库,低温库不能保持一定的低温,即使 Currently in most parts of the country 10 tons to 50 tons of small cold storage, any use of freon as the evaporator evaporation coil generally do not have defrosting measures, only manual sweep cream. The artificial sweep cream waste of manpower, but not safe Moreover, the defrost is not complete, affecting the refrigeration efficiency of the freezer. According to the relevant information, when the evaporator coil frost layer thickness reached 2 mm, the cooling capacity of only 70% of its initial value (see “Refrigeration Technology” 1986 the first period 38 pages). However, some frost coil thickness of the coil up to 5 ~ 6 mm, resulting in freezers freezer out of the library on time, low-temperature library can not maintain a certain low temperature, even if