Modular stator for progressive cavity devices

Abstract

A stator is provided for a progressive cavity device. The stator includes modular stator segments connected together. Each stator segment includes a front surface, a rear surface, and an internal helical cavity extending longitudinally from the front surface to the rear surface. Each stator segment also includes a set of bolt holes extending longitudinally from the front surface to the rear surface, and a set of connection holes opening at the front surface and extending at least partially longitudinally from the front surface to the rear surface. Bolts, inserted through the bolt holes into connection holes of an adjacent stator segment, connect the stator segments and align the internal helical cavities to form a continuous helical chamber.

What is claimed is: 
     
         1 . A stator for a progressive cavity device, comprising:
 a plurality of modular stator segments, each of the modular stator segments including:
 a front surface; 
 a rear surface; 
 an internal helical cavity extending longitudinally from the front surface to the rear surface; 
 a set of bolt holes extending longitudinally from the front surface to the rear surface; and 
 a set of connection holes opening at the front surface and extending at least partially longitudinally from the front surface to the rear surface, 
   wherein the plurality of modular stator segments are connected such that the internal helical cavities form a continuous helical chamber.   
     
     
         2 . The stator of  claim 1 , wherein the set of bolt holes in a first modular stator segment of the plurality of modular stator segments is configured to align with the set of connection holes in a second modular stator segment of the plurality of modular stator segments. 
     
     
         3 . The stator of  claim 1 , wherein the connection holes are threaded and configured to receive a bolt extending through the bolt hole of another modular stator segment. 
     
     
         4 . The stator of  claim 1 , wherein the set of bolt holes includes at least two bolt holes, and wherein the set of connection holes includes at least two connection holes. 
     
     
         5 . The stator of  claim 1 , wherein each of the bolt holes includes an opening to receive an installed bolt head recessed below the front surface. 
     
     
         6 . The stator of  claim 1 , wherein the internal helical cavity includes an axial rotation of at least 20 degrees and up to 45 degrees. 
     
     
         7 . The stator of  claim 1 , wherein each of the modular stator segments further includes:
 a gasket groove on one or more of the front surface or the rear surface, wherein the gasket groove surrounds an opening of the internal helical cavity.   
     
     
         8 . The stator of  claim 7 , further comprising:
 a compressible gasket configured to fit within the gasket groove and form a fluid-tight seal when a first modular stator segment, of the plurality of modular stator segments, is connected to a second modular stator segment, of the plurality of modular stator segments, with the compressible gasket therebetween.   
     
     
         9 . The stator of  claim 1 , wherein at least some of the modular stator segments include an elastomer coating on the internal helical cavity. 
     
     
         10 . The stator of  claim 9 , wherein the elastomer coating is cured prior to connecting a first modular stator segment to a second modular stator segment. 
     
     
         11 . The stator of  claim 1 , further comprising:
 bolts configured to fit within the set of bolt holes of a first modular stator segment and extend into the connection holes of a second modular stator segment.   
     
     
         12 . The stator of  claim 1 , further comprising:
 a center stator segment configured to adjoin to a first rear surface of a first modular stator segment, of the plurality of modular stator segments, and adjoin to a second rear surface of a second modular stator segment, of the plurality of modular stator segments.   
     
     
         13 . The stator of  claim 1 , wherein each of the modular stator segments, of the plurality of modular stator segments, are identical. 
     
     
         14 . The stator of  claim 1 , wherein the at least a first one of the plurality of modular stator segments includes an elastomer coating on the internal helical cavity, and wherein the elastomer coating is configured to provide an interference fit with a rotor within the continuous helical chamber. 
     
     
         15 . The stator of  claim 14 , wherein at least a second one of the plurality of modular stator segments is configured to provide an interference fit with the rotor within the continuous helical chamber. 
     
     
         16 . A method of assembling a stator for a progressive cavity device, the method comprising:
 providing a plurality of modular stator segments, each of the modular stator segments including:
 a front surface, 
 a rear surface, 
 an internal helical cavity extending longitudinally from the front surface to the rear surface, 
 a gasket groove on one or more of the front surface or the rear surface, wherein the gasket groove surrounds an opening of the internal helical cavity, 
 a set of bolt holes extending longitudinally from the front surface to the rear surface, and 
 a set of connection holes opening at the front surface and extending at least partially longitudinally from the front surface to the rear surface; 
   inserting, into the gasket groove of a first modular stator segment or a second modular stator segment, of the plurality of modular stator segments, a compressible gasket configured to fit within the gasket groove;   aligning the bolt holes of the first modular stator segment with the connection holes of the second modular stator segment;   inserting bolts through the bolt holes of the first modular stator segment and into the connection holes of the second modular stator segment; and   tightening the bolts to compress the compressible gasket and form a fluid-tight seal between the first modular stator segment and the second modular stator segment, wherein the first modular stator segment and the second modular stator segment are connected such that the internal helical cavities form a continuous helical chamber.   
     
     
         17 . The method of  claim 16 , wherein the first modular stator segment includes an elastomer coating on the internal helical cavity of the first modular stator segment, and wherein the second modular stator segment has exposed metal on the internal helical cavity of the second modular stator segment. 
     
     
         18 . The method of  claim 16 , further comprising:
 connecting to at least one of the plurality of modular stator segments, a connecting flange using the bolt holes or the connection holes of the at least one of the plurality of modular stator segments.   
     
     
         19 . A stator segment for a stator, the stator segment including:
 a front surface;   a rear surface;   an internal helical cavity extending longitudinally from the front surface to the rear surface;   a set of bolt holes extending longitudinally from the front surface to the rear surface; and   a set of connection holes opening at the front surface and extending at least partially longitudinally from the front surface to the rear surface,   wherein the modular stator segment is configured to connect to other modular stator segments such that the internal helical cavities of the stator segments form a continuous helical chamber.   
     
     
         20 . The stator segment of  claim 19 , further comprising:
 a gasket groove on one or more of the front surface or the rear surface, wherein the gasket groove surrounds an opening of the internal helical cavity.