Double-action pump cylinder

Abstract

A pump apparatus for pumping fluid from a well has a cylinder having upper and lower ends with inlet ports, a hollow pump rod defining a plurality of pump rod entry ports, a travelling two-way valve separating a cylinder interior into variable volume upper and lower chambers and first and second one-way valves mounted to the cylinder to seal the inlet ports.

What is claimed is: 
     
         1 . A pump apparatus for pumping fluid from a well comprising:
 a cylinder having upper and lower ends suspended in the well, the upper and lower ends of the cylinder having inlet ports therethrough;   a hollow pump rod reciprocably disposed in the cylinder, the pump rod defining a plurality of pump rod entry ports in a wall thereof communicated with a pump rod interior;   a travelling two-way valve disposed about the pump rod and movable therewith, the two-way valve separating a cylinder interior into variable volume upper and lower chambers;   a first one-way valve mounted to the cylinder's upper chamber and above the two-way valve and operable to allow the hollow pump rod to reciprocate through its center while allowing a seal to be maintained during increased cylinder pressure between the pump rod and stuffing box; and   a first one-way valve mounted to the cylinder above the two-way valve and operable to seal the inlet ports in the upper end of the cylinder during upward movement of the two-way valve and to allow inflow of water into the upper chamber of the cylinder during downward movement of the two-way valve; and   a second one-way valve mounted in the cylinder below the two-way valve, the second one-way valve operable to seal the inlet ports in the lower end of the cylinder during downward movement of the two-way valve and to allow inflow of water into the lower chamber of the cylinder during upward movement of the two-way valve.   
     
     
         2 . The pump apparatus of  claim 1 , the pump rod being movable relative to the two-way valve in addition to being movable with the pump rod. 
     
     
         3 . The pump apparatus of  claim 1 , the two-way valve comprising;
 an upper cup seal;   a lower cup seal; and   a two-way seal plate positioned between the upper and lower cup seals.   
     
     
         4 . The pump apparatus of  claim 3 , the pump rod entry ports movable relative to the two-way seal plate, the pump rod entry ports being positioned above the two-way seal plate during upward movement of the pump rod and below the two-way seal plate upon moving the pump rod downward in the cylinder, water from the upper chamber being directed into the pump rod interior through the pump rod entry ports during the upward movement of the two-way valve in the cylinder and water in the lower chamber being directed into the pump rod interior through the pump rod entry ports during the downward movement of the two-way valve. 
     
     
         5 . The pump apparatus of  claim 3 , the lower cup seal comprising an inverted upper cup seal. 
     
     
         6 . The pump apparatus of  claim 3 , the upper cup seal comprising an upward facing cup seal and the lower cup seal comprising a downward facing cup seal. 
     
     
         7 . The pump apparatus of  claim 1 , fluid from the lower chamber being directed into the pump rod interior through the pump rod entry ports during downward movement of the two-way valve and fluid from the upper chamber being directed into the pump rod interior thorough the pump rod entry ports during upward movement of the two-way valve. 
     
     
         8 . A pump apparatus for pumping fluid from a well comprising:
 a cylinder having upper and lower ends and defining a cylinder interior;   a hollow pump rod disposed in the cylinder, the hollow pump rod defining a pump rod interior and defining a plurality of pump rod entry ports communicating the cylinder interior with the pump rod interior;   a first check valve at an upper end of the cylinder configured to permit flow into the cylinder from the well through the upper end thereof and to prevent flow from the cylinder to the well therethrough;   a second check valve at the lower end of the cylinder configured to permit flow into the cylinder from the well through the lower end and to prevent flow from the cylinder to the well therethrough; and   a travelling valve positioned between the upper and lower check valves and movable with the pump rod, water being directed into and delivered upward in the pump rod interior during both the upward and downward travel of the travelling valve.   
     
     
         9 . The pump apparatus of  claim 8 , the travelling valve comprising:
 an upper seal;   a lower seal; and   a two-way seal plate positioned between the upper and lower seal, the pump rod being movable relative to the two-way seal plate.   
     
     
         10 . The pump apparatus of  claim 9 , the pump rod movable such that the pump rod entry ports are positioned above the two-way seal plate during upward movement of the travelling valve and below the two-way seal plate during downward movement of the two-way seal plate. 
     
     
         11 . The pump apparatus of  claim 8  further comprising:
 the upper end of the cylinder defining a plurality of upper inlet ports therethrough, the first check valve configured to block flow into the cylinder through the upper inlet ports during upward movement of the travelling valve and to permit flow therethrough during downward movement of the travelling valve; and 
 the lower end of the cylinder defining a plurality of lower inlet ports therethrough, the second check valve configured to block flow into the cylinder through the lower inlet ports during downward movement of the travelling valve and to permit flow therethrough during upward movement of the travelling valve. 
 
     
     
         12 . The pump apparatus of  claim 8 , the pump rod having a lower end terminating at the travelling valve. 
     
     
         13 . The pump apparatus of  claim 8 , further comprising:
 an upper limit on the pump rod; and   a lower limit on the pump rod, the upper and lower limits positioned to limit the travel of the pump rod relative to the travelling valve.   
     
     
         14 . The pump apparatus of  claim 13  the travelling valve comprising a two-way seal plate in an interior thereof, the pump rod extending through the two-way seal plate, wherein the upper and lower limits engage the two-way seal plate during movement of the pump rod to limit the travel of the pump rod relative to the travelling valve. 
     
     
         15 . A pump apparatus comprising:
 a cylinder disposed in and communicated with a well having fluid therein;   a hollow pump rod defining a pump rod interior reciprocably disposed in the cylinder;   a travelling valve positioned on the pump rod and movable therewith and also movable relative thereto; and   the fluid being delivered into the interior of the pump rod as a result of the reciprocating of the pump rod in the cylinder.   
     
     
         16 . The pump apparatus of  claim 15 , further comprising:
 a seal cap at a bottom end of the pump rod, the pump rod defining a plurality of entry ports communicated with the pump rod interior, the pump rod entry ports positioned in an interior of the travelling valve.   
     
     
         17 . The pump apparatus of  claim 16  the travelling valve comprising:
 an upper seal; 
 a lower seal; 
 a two-way seal plate between the upper and lower seal plates, the pump rod sealingly received in an opening in the two-way seal plate. 
 
     
     
         18 . The pump apparatus of  claim 17 , the upper and lower seals comprising generally identical opposite facing cup seals. 
     
     
         19 . The pump apparatus of  claim 15  further comprising:
 a first check valve at an upper end of the cylinder positioned to allow flow into the cylinder only during downward movement of the pump rod; and 
 a second check valve at a lower end of the cylinder positioned to allow flow into the cylinder only during upward movement of the pump rod. 
 
     
     
         20 . The pump apparatus of  claim 15 , the travelling valve dividing the cylinder into variable volume upper and lower chambers, fluid being directed into the pump rod interior from the upper chamber during upward movement of the pump rod and fluid being directed into the pump rod interior from the lower chamber during downward movement of the pump rod.