Pump drive head with integrated stuffing box and clamp

Abstract

The improved pump drive head ( 1 ) has an integrated stuffing box ( 9 ) and comprises: a power transmission ( 3, 4 ) coupled to the rotating pump driveshaft ( 8 ) within a crude oil well; a stuffing box ( 9 ) to retain the pressure; a thrust assembly ( 6 ) adapted to take the tensile force exerted on said pump shaft. It further has said power transmission comprised of a tube ( 5, 16 ) arranged to be rotated coaxially with the shaft ( 8 ) and having at least two different diameters. The rotary seals ( 20; 50 ) fit over the small outside diameter of the tube to establish fluid-tightness between said tube and the body ( 19 ) of the stuffing box. The working diameter ( 51 ) of the seals ( 20; 50 ) is smaller than the large outside diameter of said tube ( 5, 16 ). Static seals ( 17 ) are provided between the tube and the shaft ( 8 ). Thus, the static seals ( 17 ) and rotary seals ( 20; 50 ) are adapted to come away along with said tube and the retainer ring ( 22 ) for the seals. Advantageously, associated with said head is the improved clamp ( 10 ) for locking the rotary pump driveshaft ( 8 ) in crude oil wells, which clamp includes a jaw pair ( 35, 36 ), a pull one ( 35 ) and a push one ( 36 ) operated by means of a screw ( 38 ) acting with its end on one jaw ( 35 ) and engaging a threaded hole in the other jaw ( 36 ).

1 . An improved pump drive head having an integrated stuffing box and comprising: 
 a power transmission coupled to a rotating pump drive shaft within a crude oil well;    a stuffing box to retain the pressure; and    a thrust assembly adapted to take the tensile force exerted on said pump shaft,    wherein said power transmission comprises a tube arranged to be rotated coaxially with the shaft and having at least two different diameters,    wherein the rotary seals fit over the small outside diameter of the tube to establish fluid-tightness between said tube and the body of the stuffing box, the outside diameter of the seals being smaller than the large outside diameter of said tube, and    wherein the tube-to-shaft fit incorporates static seals and the static ones and rotary ones of the seals are adapted, by virtue of a retainer ring provided, to come away along with said tube and the component parts associated with the seals inside said stuffing box.    
   
   
       2 . An improved head according to  claim 1 , wherein the tube, being rotated coaxially with the shaft, is connected with its bottom end axially to a sleeve for rotation therewith and jointly defining said large and small diameters, the small diameter locating inside the stuffing box and the tube and sleeve, once connected together, forming a unitary piece.  
   
   
       3 . An improved head according to  claim 1 , wherein a rotary gasket is provided on the bottom end of said tube/sleeve for rotation therewith, the outside diameter of the gasket being a labyrinth pattern.  
   
   
       4 . An improved head according to  claim 1 , wherein said gasket is connected to the retainer ring of the seals on said tube/sleeve of the stuffing box.  
   
   
       5 . An improved head according to  claim 1 , wherein an outside-communicated tapping hole is provided downstream of the gasket and/or the respective oil seals in the direction of the pressurized flow from the well.  
   
   
       6 . An improved head according to  claim 1 , wherein, when the rotary seals comprise packing seals, an oil seal is provided downstream of the rotary seals and of the inlet hole for the liquid lubricant to the packing, the packing being mounted between said tube/rotating sleeve and the inner seat of the stuffing box.  
   
   
       7 . An improved head according to  claim 1 , wherein the packing is mounted on said rotating sleeve through at least one detent ring and a pre-load spring between the packing and said retainer ring.  
   
   
       8 . An improved head according to  claim 1 , wherein the packing is mounted around the small diameter of said tube/rotating sleeve and is held there by at least one axial retainer ring and a pre-load spring placed between the packing and the axial thrust assembly.  
   
   
       9 . An improved head according to  claim 2 , wherein the static seals are placed for reduced radial bulk in the joint region between said tube and said sleeve, and are compressed there to make a tight seal as said tube and sleeve are made fast together.  
   
   
       10 . An improved head according to  claim 1 , wherein the static seals are placed for convenient replacement in the joint region between said tube and the shaft, and make a tight fit within the skirt of the top cover.  
   
   
       11 . An improved head according to  claim 1 , wherein said tube is connected to the thrust assembly for rotation therewith by a rotating hub held in place by a guiding tighten-down means.  
   
   
       12 . An improved head according to  claim 11 , wherein said guiding tighten-down means comprises a rolling thrust bearing and a bell enclosing said hub and said thrust bearing.  
   
   
       13 . An improved head according to  claim 11 , wherein said guiding tighten-down means comprises a rolling thrust bearing disposed in the upper portion of the drive housing and a bell covering said hub and thrust bearing.  
   
   
       14 . An improved head according to  claim 11 , wherein said hub is formed on its inside diameter with an axial slot for pulling out the connection tongue between said tube and the drive.  
   
   
       15 . An improved head according to  claim 6 , wherein the packing pre-loading spring in the stuffing box is disposed inside a split casing to prevent overloading the spring when in the compressed state.  
   
   
       16 . An improved head according to  claim 8 , wherein a ring spacer is provided in the stuffing box which is bored for communication with the liquid lubricant inlet hole.  
   
   
       17 . An improved head according to  claim 16 , wherein said bored ring spacer is formed with an annular seat for a lip-type oil seal arranged to contact the diameter of said tube/sleeve.  
   
   
       18 . An improved head according to  claim 16 , wherein said bored ring spacer is formed with an axial middle ledge for insertion past the lip of an adjacent ring seal.  
   
   
       19 . An improved head according to  claim 1 , wherein a gasket carrying a labyrinth pattern on its inside diameter is keyed to the bottom end of the sleeve for rotation therewith.  
   
   
       20 . An improved head according to  claim 1 , wherein a shaft locking clamp, placed within the body of the stuffing box, comprises a jaw pair, one pulls and one pushes, operated through a screw arranged to act with its end on one jaw and engaged in a threaded hole formed in the other jaw.  
   
   
       21 . An improved head according to  claim 20 , wherein said push and pull jaws are operated through a screw arranged to act with its end on the push jaw and engaged in the threaded hole formed in the pull jaw.  
   
   
       22 . An improved head according to  claim 20 , wherein the stem of the screw is cylindrical and fits through a seal on the cover.  
   
   
       23 . An improved head according to  claim 20 , wherein guide and elastic bias members are provided between the pull jaw and the cover.  
   
   
       24 . An improved head according to  claim 1 , wherein a clamp with self-centering jaws is associated with the body of the stuffing box, the jaws gripping the shaft in a wedge contact relationship of the outer surfaces of the jaws to the inner surface of the sliding body of the clamp under the action of the tighten-down screw.  
   
   
       25 . An improved head according to  claim 24 , wherein the wedge contact is advantageously achieved by provision of a conical surface taper.  
   
   
       26 . An improved head according to  claim 24 , wherein the radial gripping movement of the jaws is guided by a prismatic fit to the clamp housing or cover.  
   
   
       27 . An improved head according to  claim 24 , wherein an elastic means is mounted between the two jaws to open them when the clamping action is released.  
   
   
       28 . An improved head according to  claim 24 , wherein the shaft-gripping surfaces are semicircular about a center that is offset from the shaft centerline in a direction toward the opposite jaw.  
   
   
       29 . A clamp for locking the rotary pump drive shaft in crude oil wells, comprising: 
 jaws adapted to be closed around the drive shaft by screws,    wherein said jaws are paired, one pulls and one pushes, for operation by a screw acting with its end on one jaw and engaged in a threaded hole formed in the other jaw.    
   
   
       30 . A clamp according to  claim 29 , wherein it comprises a jaw pair, one pulls and one pushes, for operation by means of a screw acting with its end on the push jaw and engaged in a threaded hole formed in the pull jaw.  
   
   
       31 . A clamp according to  claim 29 , wherein the stem of the screw is cylindrical and fits through a seal on the cover.  
   
   
       32 . A clamp, according to  claim 29 , wherein between the pull jaws and the cover there are guide and elastic-reaction parts.  
   
   
       33 . A clamp for locking the rotary pump drive shaft in crude oil wells, comprising: 
 jaws adapted to be closed around the drive shaft by means of a screw,    wherein the self-centering jaws are operated to close by a wedge contact relationship established between the outer surfaces of the jaws and the inner surface of the sliding body of the clamp under the action of the tighten-down screw.    
   
   
       34 . A clamp according to  claim 33 , wherein the wedge contact is achieved by provision of a conical surface taper.  
   
   
       35 . A clamp according to  claim 33 , wherein the radial gripping movement of the jaws is guided by a prismatic fit to the clamp housing or cover.  
   
   
       36 . A clamp according to  claim 33 , wherein an elastic means is mounted between the two jaws to open them when the clamping action is released.  
   
   
       37 . A clamp according to  claim 33 , wherein the shaft-gripping surfaces are semicircular about a center that is offset from the shaft centerline in a direction toward the opposite jaw.