Abstract: A two chamber heat transfer unit configured such that hazardous air can circulate through one of the chambers and potential ignition source components are contained in another chamber through which the gas to be heated or cooled will circulate.

Abstract: A two chamber heat transfer unit configured such that hazardous air can circulate through one of the chambers of the heat transfer unit and any potential ignition source components are contained in another pressurized chamber of the heat transfer unit.

Abstract: A two chamber heat transfer unit configured such that hazardous air can circulate through one of the chambers of the heat transfer unit and any potential ignition source components are contained in another pressurized chamber of the heat transfer unit.

Abstract: A two chamber heat transfer unit configured such that hazardous air can circulate through one of the chambers and potential ignition source components are contained in another chamber through which the gas to be heated or cooled will circulate.

Abstract: A two chamber heat transfer unit configured such that hazardous air can circulate through one of the chambers and potential ignition source components are contained in another chamber through which the gas to be heated or cooled will circulate.

Abstract: A two chamber heat transfer unit configured such that hazardous air can circulate through one of the chambers and potential ignition source components are contained in another chamber through which the gas to be heated or cooled will circulate.

Abstract: A pressure relief valve includes a two-piece housing having therein a generally circular diaphragm backed by a spring biased plate. The outer edge of the diaphragm is captured between the two pieces of the housing and to provide a first sealing area. The central portion of the diaphragm has a circular opening therein with an annular sealing lip formed thereabout. The sealing lip provides a seal when the spring biased plate moves the diaphragm against a flat circular seat. When pressure at the inlet of the housing overcomes the spring biasing force, the diaphragm is moved away from the seat and the gas is relieved through an outlet in the housing.

Abstract: A coupling member adapted for joining in tandem a pair of axial flow valves includes a central hub region having back to back bosses extending longitudinally therefrom and a plurality of rib members extending radially therefrom. The spaces between the rib members provide a fluid flow path between the valve bodies. The interior of each of the bosses is hollow to provide means for communicating with the interior of the valve bodies.

Abstract: An improved axial flow valve construction includes a valve body and a pair of identical and interchangeable end closure members. The valve body includes a cylindrical opening defining the interior of the valve body, a first plurality of open channels extending from a first end of the valve to the valve body interior and a second plurality of open channels extending from the valve body interior to the second end of the valve body. A flexible tubular sleeve is located within the cylindrical opening. The valve further includes means for providing external communication to the first plurality of open channels and means for providing external communication to the second plurality of open channels.