Abstract: A centrifugal air cleaning apparatus includes a housing defining a filter compartment containing a generally tubular filter cartridge having the open upper end thereof in communication with an air outlet opening through the top wall of the filter compartment. A vacuum source is provided in communication with that air outlet opening to effect vacuum pressure within the filter compartment. An air inlet opening through a side wall of the filter compartment has a multi-baffled flame arrestor associated therewith for extinguishing sparks in the fumes being drawn into the filter compartment and for directing the incoming air flow tangentially of the filter cartridge so that a portion of the pollutants carried in the fumes are separated by gravity before the fumes contact the filter cartridge. An injector conduit is provided within the flame arrestor to facilitate blowdown.

Abstract: A self contained mechanical bleed control apparatus for a fluid conveying system, such as a central vacuum system or a pressurized air system, includes a slide member housing which slidably supports an orifice plate having an air foil on one end disposed within a main flow conduit just upstream from a vacuum producer or downstream from the compressor in a pressurized fluid system. A source of bleed fluid communicates with the slide member housing and is valved by movement of the orifice plate. The orifice plate is biased to a position for communication of bleed fluid into the main conduit under low flow conditions. Increased flow through the main conduit acts on the air foil to slide the orifice plate against the urging of the biasing force to cut off the bleed fluid supply.