Abstract: A shut-off valve for the automotive fuel system is operable to shut off the fuel flow whenever a positive pressure exists in the fuel line between the fuel tank and the shut-off valve. The shut-off valve may be employed in combination with a fuel pump or may be employed separately in the fuel line and comprises a flexible diaphragm connected by a stem directly to the valve member and movable with the valve member. The diaphragm air chamber has an air vent controlled by a vent valve providing a relatively large opening for bleeding in air and providing a relatively small opening for exhausting air from the diaphragm air chamber. The vent valve thus permits a relatively fast movement of the valve member to an open position and a relatively slow or restricted movement of the valve member toward a closed or partially closed position.

Abstract: An automatic control system for high pressure blower applications prevents surging under variable supply flow rate requirements and achieves maximum efficiency of operation. The supply flow rate establishes the set point of a proportional plus reset controller, the latter receiving a feedback signal corresponding to the static discharge pressure of the supply blower and responding thereto for controlling the output of the supply blower. A return blower is controlled either through a characterizer relay in proportion to the control of the supply blower to maintain a fixed precalibrated relationship between supply and return flow rates or by a further proportional plus reset controller responsive to the supply flow rate, for establishing the set point thereof, and to the return flow rate, as a feedback signal thereto, for controlling the output of the return blower.