Figure 1 is a structural diagram of a drying filter. The outer shell is formed by closing with a copper tube, and there are two types of inlet and outlet interfaces at both ends: same diameter and different diameter. The inlet end is a coarse metal mesh, and the outlet end is a fine metal mesh, which can effectively filter impurities. Molecular sieves with excellent moisture absorption properties are used as desiccants to absorb moisture from the refrigerant, ensuring smooth capillary flow and normal operation of the refrigeration system. When the desiccant fails due to excessive water absorption, it should be replaced in a timely manner.