Abstract: A bleed system for venting pressurized gas at a selectively adjustable flow rate. The bleed system includes a plurality of bleed flow paths of different lengths providing varying resistance to the flow of air and a bleed path selector mechanism movable between a plurality of different settings corresponding with the different flow paths. The flow paths are defined by channels formed in a face of a plate and are connectable in series. The bleed system is applied in a runaway control for an air motor which shuts off the motor when its speed exceeds a predetermined cut-off speed. Selection of a different bleed flow path adjusts the cut-off speed.

Abstract: An improved runaway control for an air motor operable on increase in speed of the air motor above a speed limit stop the motor. The control includes a pressure-responsive device having an air chamber for air under pressure. Further provided is a movable member which moves away from a first position in response to increase in air pressure in the chamber above a predetermined limit to a second position, and movable back to the first position on reduction of pressure in the chamber below the limit. The movable member, when in its first position, enables the operation of the air motor, and when in its second position, cuts off the operation of the motor. An air pump is interconnected with the air motor for operation simultaneously with the motor for delivering air under pressure at a rate related to the speed of the motor to the chamber.

Abstract: A safety shutdown circuit for a pneumatic pump system. The pump system includes a manifold assembly for discharging pumped liquid. The liquid is discharged from the system by a reciprocating piston apparatus which drives a liquid pump cylinder. The pump system is provided with a pneumatic safety circuit for monitoring the stroke time or rate of the reciprocating air cylinder. The safety circuit includes a safety shutdown valve and a pneumatic timer associated with the shutdown valve. The pneumatic timer vents air supply within the safety circuit after a predetermined time interval. If a leak or failure occurs in the pump system, the reciprocating piston apparatus will complete a stroke in less time than the predetermined time as a result of the pressure loss incident to the leak or failure. In such event, the air supply within the safety circuit is directed through the shutdown valve to the pump system START valve to deactivate the system.