Mechanical vacuum pump exhaust filters should not be mounted directly to the vacuum pump discharge. They should be piped a minimum of 6 feet above the pump to insure the condensing of oil in the riser, and not premature wetting out of the element causing blockage.
If the installation involves long piping beyond the filter , be sure the friction loss due to piping was taken into account when sizing the vacuum pump exhaust system. The maximum temperature limit of a standard filter is 200 F.
The filter may be installed indoors or out. Air flow through the filter element is typically inside to outside. The inlet connection of the filter is on the bottom. The outlet is on the side or top. A drain connection is sometimes located on the bottom of the unit for draining oil from the housing .
When extended distances of pipe are used to remove vapors from a vacuum pump, the addition of mechanical draft of some type is recommended. This will assure the proper removal of gasses through the mechanical pump exhaust filter and away from the pump.
Back pressure at the exhaust of the vacuum pump can cause excessive pressure and the condensing of process contaminates in the vacuum fluid.