Pump loss-of prime automatic shut off valve

Abstract

A pump shutoff device is provided wherein compressed air supplied to the air inlet port of the over speed control device enters an air pressure chamber, and then proceeds to an adjacent air exhaust chamber. From there, the air passes to an outport which is connected,directly to the inlet port of the air motor of an air-operated piston pump spool located inside the body of the device, is shaped such that the valve spool functions to allow passage of air freely from the air pressure chamber to the air exhaust chamber. Compressed air is connected through a series of unrestricted conduits,ports and chambers continuous from the compressed air supply to the air motor of a pump. The air motor is energized by compressed air to provide continuous pumping. Positive pressure existing in the fluid pressure chamber exerts an axial thrust on the spool. Adjacent to the air chambers and opposite the position of the fluid pressure chamber is a coil compression spring. The spool and the spring are shaped so as the spring is compressed it exerts an axial force on the spool in opposition to the axial force on the spool exerted by the fluid pressure chamber

1 . An over speed control device for fluid pumps comprising:
 a) A longitudinal assembly;   b) An air inlet chamber contained in said assembly;   c) An air inlet port to said chamber;   d) An air pressure chamber aligned and on the opposite side of said air inlet chamber;   e) An air exhaust chamber aligned and on the opposite and aligned with said inlet air chamber;   f) An air outlet port from said air exhaust chamber provided for connecting to an inlet part of a pump air motor;   g) A valve spool in said assembly positioned contigenous to said air exhaust chamber; and   h) A compression coil spring arranged to exert axial pressure on said valve spool;   
     said air inlet chamber,air exhaust chamber,valve spool and compressor spring being arranged such that when positive pressure is exerted in the air pressure chamber a force is then applied on the valve dpool,compressing said coil spring whereby said spool is shifted and thereby interrupts and prevents passage of comressed air from said air inlet chamber to said air exhaust chamber. 
   
   
       2 . The over speed control device of  claim 1  provided with associated mechanism to obtain an initial condition of pump prime. 
   
   
       3 . The device of  claim 2  wherein the associated mechanism compromise a handle that when pulled manually functions to dispense the valve spool to an air open condition. 
   
   
       4 . The speed control device of  claim 1  in functional combination with a responding piston air pump. 
   
   
       5 . The speed control device of  claim 1  in functional combination with a rotary air operated pump. 
   
   
       6 . The overspeed control device of  claim 1  wherein a continually-compressed gas in the spring body chamber is used in place of a mechanical spring. 
   
   
       7 . A method for automatically shutting down ait operated fluid dispensing pumps upon loss of pump prime comprising spring-means to permit an open passage for the dispensing of fluid from the pump so long as fluid prime exists, said spring-means being extended to stop the pumped air supply and shut off the fluid passage upon loss of prime due to air leakage or fluid supply depletion and fluid pressure means fuctioning to compress sain spring-means and enable air supply and dispensing of fluid when fluid prime is restored.