Abstract: Gas at elevated temperature from a compressor (50) is fed to a first cooling coil (14) and thence to a second cooling coil (18) in chamber (16). The cooled gas at line (20) enters a chamber (22) where water and oil (if present) separate. A contaminant-free stream of compressed gas is further purified at filter chambers (28, 34). A portion of the gas flow, carrying the liquefied water or water/oil mixture is returned via reducing valve (44) to the interior of chamber (16) where it travels up riser pipe (46) in heat-exchanging relationship with the gas in coil (18) and emerges through port (48) as a condensate-free gas stream, the condensate having re-volatilized after passage through the reducing valve (44). The described arrangement minimizes or eliminates watery waste and cools the gas stream without the need for a powered cooler or supply of cooling water.

Abstract: A filter element for gas or liquid comprises a layer of glass, ceramic, metal, mineral wool or organic fibers containing, wholly within the layer, an apertured sheet, for example of steel or aluminum, the fibers being bound to one another throughout the layer and through the apertures, as well as to the sheet itself, by a synthetic resin such as silicone resin or polyurethane. The filter element is formed by mounting the apertured sheet a selected distance above a filter surface on which the fibers build up while a slurry containing the fibers is drained through the filter surface. When the fibers have built up to a predetermined distance above the sheet, the fibers containing the sheet are removed and the assembly impregnated with a synthetic resin and cured. Two or more grades of slurry mixture may be used in succession to produce a density grading through the thickness of the fibrous layer.