The 824-131 Dual Stage Filters combine the high efficiency performance advantages of our unique Centrifugal Separation method, an extended surface, sub-micron Coalescing Element, together with one of GWs' dependable automatic drains. In combination the end result is that heavy bulk liquids are removed by centrifugal motion. Oil varnish and water aerosols .03 micron and larger are coalesced. Abrasive particles above .3 microns are retained. Accumulated liquid contaminates are automatically expelled by the trouble free operation of the GW automatic drain. Without these contaminants to contend with, your auxiliary equipment (i.e. sanding, horn, bell, miscellaneous air valves and safety related brake equipment) will operate more reliably. In addition, contamination in the form of water, solids and oil varnish, if not removed properly, will lead to unscheduled maintenance, down time and unnecessary added costs. The 824-131 is supplied with our 580 Series Air Actuated (double seated) Automatic Drain Valve and requires a separate control air source on a cycle basis for actuation. An air signal from the compressor unloader, solenoid valve or the microprocessor on a programmable basis is suggested. Coalescer Kits for several older 824 centrifugal filters are available for upgrade. GW is also prepared to upgrade your filters using our remanufacturing services if you wish.