Abstract: A system for removing substantially all particular material from an air flow through a passage provides the air flow passage with an area of enlarged circumference containing a coaxial mounted cyclone fan and stationary vanes. The cyclone fan includes a motor driving a cage provided with a plurality of vanes. The stationary vanes are shaped similar to like vanes on the cyclone fan, but are turned in the reverse direction.

Abstract: An air filtering apparatus and filter mounting device for sealing a filter within an air filtering apparatus, utilizes at least one cam surface to force a filter to compress a gasket to provide an effective seal between the air filter and its associated air outlet.

Abstract: An explosion proof compressor and method for explosion proofing a compressor for use with air conditioning or refrigeration system in a hazardous location where flammable gases or vapors may exist places the electrical supply terminals for the compressor within a gas tight housing which is pressurized with low pressure refrigerant gas being compressed by the compressor. The gas tight housing is in a fluid-transmitting relationship with a pressure responsive switch, whereby upon a pre-selected decrease in the pressure within the gas tight housing, the pressure responsive switch terminates the supply of electrical power to the compressor motor.