Abstract: In a heat recovery ventilator, a housing has an inlet and an outlet for a first fluid flow and an inlet and an outlet for a second fluid flow, and has a heat exchange panel assembly having two sets of panels alternately arranged to form a first and a second flow path for each of the first fluid flow and the second fluid. The first flow path is in fluid communication with the first fluid flow inlet and outlet and the second flow path is in fluid communication with the second fluid flow inlet and outlet. The heat exchange panel is slidably mounted within the housing. A first fan and a second fan is mounted on a fan mounting plate. The fan mounting plate is hingedly mounted to the housing and is pivotable between a servicing position and an operational position.

Abstract: A drive coupling for selectively disengaging a driving shaft and a driven shaft upon rotation of the driving shaft in one direction. The coupling comprises a pair of one-way clutches and a one space ratchet means so arranged to couple the shafts when the driving shaft is rotating in the normal direction and to uncouple the shafts upon the opposite rotation of the driving shaft. The coupling device is capable of remote operation as by reversing the current flow to the motor.Such a device provides a convenient means for coupling and uncoupling pump stages in a submersible pump thus permitting adjustment of the performance of the pump by the addition or subtraction of pump stages without pulling the entire assembly from the well.