Methods and Apparatus for Enhancing Elastomeric Stator Insert Material Properties with Radiation

Abstract

A method for manufacturing a stator for a progressive cavity motor or pump comprises (a) forming an elastomeric stator insert. In addition, the method comprises (b) exposing the elastomeric stator insert to ionizing radiation. Further, the method comprises (c) positioning the elastomeric stator insert in a stator housing to form a stator.

1 . A method for manufacturing a stator for a progressive cavity motor or pump, comprising:
 (a) forming an elastomeric stator insert;   (b) exposing the elastomeric stator insert to ionizing radiation; and   (c) positioning the elastomeric stator insert in a stator housing to form a stator.   
     
     
         2 . The method of  claim 1 , wherein (b) comprises exposing the elastomeric stator insert to at least 100 KiloGrays of ionizing radiation. 
     
     
         3 . The method of  claim 2 , wherein (b) comprises exposing the elastomeric stator insert to at least 500 KiloGrays of ionizing radiation. 
     
     
         4 . The method of  claim 2 , wherein the ionizing radiation is ionizing X-ray radiation. 
     
     
         5 . The method of  claim 2 , wherein the elastomeric stator insert is made from an elastomeric material selected from a group consisting of nitrile rubber, hydrogenated nitrile (HNBR), ethylene propylene diene rubber (EPDM rubber), Chloroprene (neoprene) and fluoroelastomers (FKM). 
     
     
         6 . The method of  claim 2 , wherein (a) comprises forming the elastomeric stator insert by an injection molding process or a transfer molding process. 
     
     
         7 . The method of  claim 2 , wherein the stator housing has a radially inner cylindrical surface and the elastomeric stator insert has a radially outer cylindrical surface that engages the inner cylindrical surface of the stator housing after (c). 
     
     
         8 . The method of  claim 1 , wherein (b) comprises exposing the elastomeric stator insert to ionizing radiation selected from a group consisting of alpha rays, beta rays, gamma rays, neutron rays, proton rays, UV rays, and X-rays. 
     
     
         9 . The method of  claim 2 , wherein (c) occurs before (b). 
     
     
         10 . The method of  claim 2 , wherein (b) further comprises:
 (b1) emitting a stream of electrons from an electron gun;   (b2) directing the stream of electrons into a target positioned between the elastomeric stator insert and the electron gun;   (b3) emitting ionizing X-ray radiation from the target; and   (b4) exposing the elastomeric stator insert to the ionizing X-ray radiation emitted in (b3).   
     
     
         11 . The method of  claim 10 , wherein the target comprises tantalum. 
     
     
         12 . The method of  claim 2 , further comprising peroxide curing the elastomeric stator insert. 
     
     
         13 . A method for manufacturing a stator for a progressive cavity motor or pump, comprising:
 (a) generating a beam of electrons;   (b) positioning a target between the beam of electrons and an elastomeric stator insert;   (c) emitting ionizing X-ray radiation from the target after (b);   (d) exposing the elastomeric stator insert to at least 100 KiloGrays of the ionizing X-ray radiation; and   (e) forming a plurality of polymer cross-links in the elastomeric stator insert with the ionizing X-ray radiation during (d).   
     
     
         14 . The method of  claim 13 , wherein (d) comprises exposing the elastomeric stator insert to at least 500 KiloGrays of the ionizing X-ray radiation. 
     
     
         15 . The method of  claim 13 , further comprising positioning the elastomeric stator insert into a stator housing before or after (d). 
     
     
         16 . The method of  claim 15 , wherein the stator housing has a radially inner cylindrical surface and the elastomeric stator insert has a radially outer cylindrical surface that engages the inner cylindrical surface of the stator housing. 
     
     
         17 . The method of  claim 13 , wherein the target comprises tantalum. 
     
     
         18 . The method of  claim 13 , further comprising:
 emitting secondary radiation from a plurality of energy activated elements in the elastomeric stator insert in response to (d).   
     
     
         19 . A progressive cavity pump or motor, comprising:
 a stator having a central axis and including a stator housing and a stator insert disposed within the stator housing, wherein the stator includes a helical bore defined by the elastomeric stator insert;   a rotor rotatably disposed within the helical bore of the stator, the rotor having a radially outer helical surface;   wherein the stator insert comprises an elastomeric material including a plurality of polymer chains connected by a plurality of cross-links induced by ionizing radiation.   
     
     
         20 . The progressive cavity pump or motor of  claim 19 , wherein the elastomeric material is selected from a group consisting of nitrile rubber, hydrogenated nitrile (HNBR), ethylene propylene diene rubber (EPDM rubber), Chloroprene (neoprene) and fluoroelastomers (FKM). 
     
     
         21 . The progressive cavity pump or motor of  claim 19 , wherein the stator housing has a radially inner cylindrical surface and the elastomeric stator insert has a radially outer cylindrical surface that engages the inner cylindrical surface of the stator housing. 
     
     
         22 . The progressive cavity pump or motor of  claim 19 , wherein the stator housing has a radially inner helical surface and the stator insert engages the inner helical surface of the stator housing. 
     
     
         23 . The progressive cavity pump or motor of  claim 22 , wherein the stator insert has a substantially uniform radial thickness. 
     
     
         24 . The progressive cavity pump or motor of  claim 19 , wherein the elastomeric stator insert includes a plurality of energy activated elements configured to emit secondary radiation in response to ionizing radiation. 
     
     
         25 . The progressive cavity pump or motor of claim C 6 , wherein the plurality of energy activated elements are selected from the group consisting of peroxides, coagents, vinyl containing acrylates, vinyl containing methacrylates, and modified bismaleimides.