DRIERS FOR DEHYDRATING A CIRCULATING FLUID-NAMELY, A REFRIGERANT FLUID, INCLUDING A HOUSING CONTAINING A DESICCATING AGENT THROUGH WHICH THE FLUID IS CAUSED TO PASS; AND STRAINERS OF SIMILAR CONSTRUCTION LACKING A DESICCATING AGENT BUT PROVIDED WITH INTERNAL FILTER MEANS THROUGH WHICH THE FLUID PASSES TO SEPARATE FOREIGN MATTER THEREFROM