Piston pump

Abstract

A pneumatic groundwater retrieving piston pump comprising generally of a piston and a foot valve is disclosed. A pneumatic driver slides the piston assembly up and down inside the foot valve assembly, which is connected to the driver by means of a stationary length of pipe. The drive shaft of the pneumatic driver is connected to the piston assembly by means of a polypropylene coated epoxy resin based rod. On the upward stroke the foot valve opens and lets water enter the volume below the piston assembly and the piston assembly check valve is closed and lifts the column of water. On the down stroke the foot valve closes holding the column of water and the piston check valve open, and allows the water to pass through to recharge the cylinder for the next lift cycle.

1 . A piston driven pump assembly for withdrawing subterraneous liquids from a well comprising: 
 a pump housing having an upper, middle and lower housing elements, the upper housing element comprising the air cylinder body, the middle housing element comprising the drive shaft housing, and the lower housing element comprising the piston valve body said upper, middle and lower housing elements in fluid communication with each other; matter    a piston assembly slidably received within said piston valve body and having a piston valve assembly contained therein, piston valve body having sealing means preventing liquid from traveling around said piston during functioning;    a lower foot valve assembly comprising a foot valve and a valve housing affixed to the bottom of said piston valve body, said foot valve having sealing means preventing liquid from traveling around said valve during functioning;    a piston shaft located within the pump housing having an upper and lower end, said piston shaft attached at a lower end to the piston assembly;    a drive shaft contained within said drive shaft housing, connected at a lower end to said piston shaft by a pivotal tolerant connection, and connected at an upper end to a reversing valve assembly;    wherein the reversing valve assembly provides reciprocating actuating input to the drive shaft, piston shaft and piston assembly, said piston valve body permits liquid to flow through on the downward stroke of said piston assembly only, from a position below said piston valve body to a position above said valve body, while said foot valve allows liquid to flow into pump assembly on the upward stroke only from a position below said foot valve to a position above said foot valve.    
   
   
       2 . The piston driven pump assembly of  claim 1  wherein the connection between said piston shaft and said drive shaft comprises a wobble joint, allowing a determined amount of lateral play between said piston shaft and said drive shaft.  
   
   
       3 . The piston driven pump assembly of  claim 1  further comprising an intake screen attached to a lower end of said lower foot valve assembly.  
   
   
       4 . The piston driven pump assembly of  claim 1  wherein the lower foot valve assembly is fixed in position between said piston valve body, and said intake screen.  
   
   
       5 . The piston pump assembly of  claim 1  wherein said reversing valve assembly provides pneumatic forces actuating the drive shaft, to control the transition from the upward stroke to the downward stroke of said piston assembly.  
   
   
       6 . The piston pump assembly of  claim 1  further comprising a magnetic stroke counter acting upon said piston pump assembly.  
   
   
       7 . The piston pump assembly of  claim 1  further comprising a inner sleeve positioned within said lower housing through which said piston assembly is slideably received.  
   
   
       8 . The piston pump assembly of  claim 6  wherein the sealing means of said piston valve body is omitted due to diametric clearances of less than 0.0010 inches between the piston valve body and the inner sleeve of said lower housing  
   
   
       9 . A Piston driven pump assembly for withdrawing subterraneous liquids from a well comprising: 
 a pump housing having an upper, middle and lower housing elements, the upper housing element comprising the air cylinder body, the middle housing element comprising the drive shaft housing, and the lower housing element comprising the piston valve body said upper, middle and lower housing elements in fluid communication with each other;    an intake screen attached to a lower end of said lower foot valve assembly;    an inner sleeve positioned within said lower housing through which said piston assembly is slideably received;    a piston assembly slidably received within said piston valve body and having a piston valve assembly contained therein, piston valve body having sealing means preventing liquid from traveling around said piston during functioning;    a lower foot valve assembly comprising a foot valve and a valve housing affixed to the bottom of said piston valve body, said foot valve having sealing means preventing liquid from traveling around said valve during functioning;    a piston shaft located within the pump housing having an upper and lower end, said piston shaft attached at a lower end to the piston assembly;    a drive shaft contained within said drive shaft housing, attached at a lower end to said piston shaft via a lateral-play tolerant wobble-joint, and connected at an upper end to a reversing valve assembly;    a magnetic stroke counter acting upon said piston pump assembly;    wherein the reversing valve assembly provides reciprocating actuating force to the drive shaft, piston shaft and piston assembly, said piston valve body permits liquid to flow through on the downward stroke of said piston assembly only, from a position below said piston valve body to a position above said valve body, while said foot valve allows liquid to flow into pump assembly on the upward stroke only from a position below said foot valve to a position above said foot valve said reversing valve assembly provides pneumatic force upon the drive shaft, acts to control the supplied compressed air from the upward stroke to the downward stroke.    
   
   
       10 . The piston driven pump assembly of  claim 9  wherein the lower foot valve assembly is fixed between said piston valve body, and said intake screen.