Pre-charging pump chamber by pre-emptively opening a valve

Abstract

A reciprocating pump with chamber-charging mechanism is provided. In an example diaphragm pump, a discharge valve can be opened by the pressure of fluid leaving the pump and can also be opened by an intermittent mechanical linkage actuated by the reciprocating member powering the pump. The discharge valve is mechanically opened to allow pressure backflow into the pumping chamber, thereby charging compressible fluid mixtures and gases with an increase in pressure. The increased pressure enables the compressible fluids to open the discharge valve on the next compression stroke and exit the pump. In an implementation, the discharge valve is pushed open by the reciprocating power source in a configuration that seals the valve mechanism from well fluid. In another implementation, the discharge valve is pulled open to pre-charge the pumping chamber.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a pump for a well fluid;   a reciprocating mover in the pump to alternately inflate and deflate a diaphragm within the pump;   an inlet valve to allow the well fluid to enter the pump when the diaphragm deflates;   a discharge valve to allow the well fluid to exit the pump when the diaphragm inflates;   an intermittent mechanical linkage between the reciprocating mover and the discharge valve;   wherein the intermittent mechanical linkage causes a pressure backflow of a well fluid from outside the pump into the pump via the discharge valve;   wherein the mechanical linkage causes the pressure backflow from outside the pump during each minimum extension of the reciprocating mover charge a pumping chamber of the pump with each reciprocation of the pump.   
     
     
         2 . The apparatus of  claim 1 , wherein the intermittent mechanical linkage pulls the discharge valve open. 
     
     
         3 . The apparatus of  claim 2 , wherein the intermittent mechanical linkage pulls the discharge valve open at a minimum extension or a maximum retraction of the reciprocal mover. 
     
     
         4 . The apparatus of  claim 1 , further comprising a seal for preserving at least a valve guide of the discharge valve from the well fluid being pumped to protect a movement of the valve from the well fluid, wherein the well fluid contains one of a gas, a corrosive, a solvent, or a particulate. 
     
     
         5 . The apparatus of  claim 1 , further comprising a seal for preserving the intermittent mechanical linkage from the well fluid being pumped to protect the intermittent mechanical linkage from the well fluid, wherein the well fluid contains one of a gas, a corrosive, a solvent, or a particulate. 
     
     
         6 . The apparatus of  claim 1 , further comprising a bellows for allowing a reciprocation of the discharge valve while keeping an operating fluid of the pump separate from a well fluid being pumped without a sliding friction interface. 
     
     
         7 . A method comprising:
 establishing an intermittent mechanical linkage between a reciprocating mover of a pump and a discharge valve; and   pressurizing a pump chamber of the pump by opening the discharge valve via the intermittent mechanical linkage.   
     
     
         8 . The method of  claim 7 , wherein the intermittent mechanical linkage pulls the discharge valve open. 
     
     
         9 . The method of  claim 7 , further comprising sealing at least a valve guide of the discharge valve from a well fluid being pumped to protect a movement of the valve from the well fluid, wherein the well fluid contains one of a gas, a corrosive, a solvent, or a particulate. 
     
     
         10 . The method of  claim 7 , further comprising sealing the intermittent mechanical linkage from a well fluid being pumped to protect the intermittent mechanical linkage from the well fluid, wherein the well fluid contains one of a gas, a corrosive, a solvent, or a particulate. 
     
     
         11 . The method of  claim 7 , wherein pressurizing the pump chamber of the pump by opening the discharge valve via the intermittent mechanical linkage enables a pressure backflow into the pump via the discharge valve. 
     
     
         12 . A diaphragm pump, comprising:
 a reciprocating mover;   a pump chamber;   an inflatable diaphragm in the pump chamber in fluid communication with the reciprocating mover;   an outlet check valve to allow a pumped well fluid to open the outlet check valve and exit the pump chamber;   a valve stem on the outlet check valve to open the outlet check valve during each minimum extension of the reciprocating mover and each inflation of a diaphragm of the diaphragm pump when the valve stem is mechanically moved by the reciprocating mover; and   wherein each minimum extension of the reciprocating mover pre-charges the pump chamber with an increased pressure from a well fluid outside the pump and the inflation of the diaphragm and the minimum extension of the reciprocating mover.   
     
     
         13 . The diaphragm pump of  claim 12 , wherein the valve stem is slidably disposed in axial alignment with the reciprocating mover to open the outlet check valve when the reciprocating mover pushes the valve stem. 
     
     
         14 . The diaphragm pump of  claim 12 , further comprising a tappet connected to the valve stem, wherein the reciprocating mover contacts the tappet near a maximum extension of the reciprocating mover during a pump cycle. 
     
     
         15 . The diaphragm pump of  claim 12 , further comprising a spring to maintain the outlet check valve in a closed state until the outlet check valve is opened by a mechanical push from the reciprocating mover or by a well fluid exiting the pump. 
     
     
         16 . The diaphragm pump of  claim 15 , further comprising at least one seal to isolate at least a slidable mount of the outlet check valve and the spring from a well fluid, wherein the well fluid contains one of a gas, a corrosive, a solvent, or a particulate.