The dryer filter combines the functions of a filter of impurities or moisture that may be present in the refrigerant. The filter is designed to protect metering devices (capillary or expansion valve) and compressor against foreign bodies, such as refrigeration circuit construction dirt, inlays in the lines and residues of welding, rust and metal scrap. The dryer retains the moisture of the system by not letting it circulate.
Filters must be installed immediately before all metering devices. This prevents particles from blocking the valve bore. Many valves contain a thin metal mesh filter for this purpose.
Many compressors come equipped with a filter at the suction inlet proper for a normal system with copper tubes. The compressor suction line pipe is designed to allow access to the filter.
It is recommended to use a permanent drier filter for all systems and all refrigerant fluids. Factory-assembled systems of all sizes include the filter drier that the manufacturer deems necessary.
Also widely used is a disposable type filter dryer that is installed in commercial and industrial systems of medium and high capacity refrigeration. It is located directly on the liquid line at some point between the condenser outlet and the metering device inlet.
In order for the cooling system to function properly, it is important to observe the correct placement of these filters in the refrigeration circuit, verifying the flow direction that is identified in its housing.
