Torque transmitting key for electric submersible pumps

Abstract

A torque transmitting key for electrical submersible pumps (ESP). An ESP system includes a rotatable shaft and a sleeve coupled to the rotatable shaft by an elongate key, the elongate key made of a carbide composite material, the carbide composite material including a carbide selected from the group consisting of tungsten carbide, titanium carbide and silicon carbide, and a composite material selected from the group consisting of cobalt, nickel and a combination of cobalt and nickel. An ESP system includes an elongate torque transmitting key, the elongate key coupling an ESP rotatable component to an ESP shaft such that the ESP rotatable component rotates with the ESP shaft, the elongate torque transmitting key seated in a keyway of the ESP rotatable component and a keyway of the ESP shaft, and the elongate torque transmitting key having a load optimizing cross-sectional shape.

What is claimed is: 
     
         1 . An electric submersible pump (ESP) system comprising:
 a rotatable shaft extending longitudinally through at least one impeller and diffuser stage and at least one bearing set, each of the at least one bearing set comprising a sleeve and a bushing;   the sleeve coupled to the rotatable shaft by an elongate key such that the sleeve rotates with the rotatable shaft; and   the elongate key made of a carbide composite material, the carbide composite material comprising:
 a carbide selected from the group consisting of tungsten carbide, titanium carbide and silicon carbide; and 
 a composite material selected from the group consisting of cobalt, nickel and a combination of cobalt and nickel. 
   
     
     
         2 . The ESP system of  claim 1 , wherein the composite material comprises between 6% and 10% by mass of one of cobalt, nickel or a combination thereof. 
     
     
         3 . The ESP system of  claim 1 , wherein the elongate key has one of an arch or tee cross-sectional shape. 
     
     
         4 . The ESP system of  claim 3 , wherein the elongate key has an arch cross-sectional shape and a rounded portion of the arch is seated in a keyway extending along an inner diameter of the sleeve. 
     
     
         5 . The ESP system of  claim 4 , wherein the keyway extending along the inner diameter of the sleeve is rounded to match the rounded portion of the arch. 
     
     
         6 . The ESP system of  claim 3 , wherein the elongate key has a tee cross-sectional shape and a cross of the tee is seated in a keyway in one of the shaft or the sleeve. 
     
     
         7 . The ESP system of  claim 3 , wherein the elongate key has a tee cross-sectional shape and each stepped side of the tee is seated in a keyway in one of the shaft or the sleeve. 
     
     
         8 . The ESP system of  claim 7 , wherein at least one of the keyways is stepped to match the stepped side of the tee seated in the at least one keyway. 
     
     
         9 . The ESP system of  claim 1 , wherein the elongate key has a hardness of 86 HRA or greater. 
     
     
         10 . The ESP system of  claim 1 , wherein the elongate key is about 18 inches in length. 
     
     
         11 . An electric submersible pump (ESP) system comprising:
 an elongate torque transmitting key, the elongate torque transmitting key coupling an ESP rotatable component to an ESP shaft such that the ESP rotatable component rotates with the ESP shaft;   a first side of the elongate torque transmitting key seated in a keyway of the ESP rotatable component and a second side of the elongate torque transmitting key seated in a keyway of the ESP shaft; and   the elongate torque transmitting key having a load optimizing cross-sectional shape.   
     
     
         12 . The ESP system of  claim 11 , wherein the elongate torque transmitting key is 18 inches in length and the load optimizing cross-sectional shape remains constant along the length of the elongate torque transmitting key. 
     
     
         13 . The ESP system of  claim 11 , wherein the ESP rotatable component is a sleeve of a bearing set, the elongate torque transmitting key has a partially rounded load optimizing cross sectional shape, and wherein a rounded portion is the first side of the elongate torque transmitting key seated in the keyway of the sleeve. 
     
     
         14 . The ESP system of  claim 13 , wherein the keyway of the sleeve is rounded to match the rounded portion of the first side of the elongate torque transmitting key. 
     
     
         15 . The ESP system of  claim 11 , wherein the ESP shaft extends longitudinally through a plurality of impeller and diffuser stages, and at least one impeller of the plurality of impeller and diffuser stages are keyed to the ESP shaft by the elongate torque transmitting key. 
     
     
         16 . The ESP system of  claim 11 , wherein the ESP rotatable component is a sleeve of a bearing set, the elongate torque transmitting key has a load optimizing cross sectional shape of a tee, and wherein a stepped side of the tee is the first side of the elongate torque transmitting key seated in the keyway of the sleeve, and wherein the keyway of the sleeve is stepped to match the stepped side of the tee seated in the keyway of the sleeve. 
     
     
         17 . The ESP system of  claim 11 , wherein the elongate torque transmitting key consists of tungsten carbide cobalt composite. 
     
     
         18 . The ESP system of  claim 17 , wherein the tungsten carbide cobalt composite is greater than 6% cobalt by mass. 
     
     
         19 . The ESP system of  claim 11 , wherein the load optimizing cross-sectional shape is one of arch, round, tee, asymmetrical tee or L shaped. 
     
     
         20 . A method of making a torque transmitting key for an electric submersible pump (ESP) comprising:
 extruding a carbide composite material through a die having a die shape to form an elongate key having a cross sectional shape of the die shape;   heat treating the elongate key to harden the carbide composite material; and   mating the hardened elongate key to an ESP shaft on a first side and a sleeve on a second side.   
     
     
         21 . The method of  claim 20 , wherein the cross sectional shape of the elongate key is an arch and a rounded top of the arch is the second side of the hardened elongate key mated to the sleeve. 
     
     
         22 . The method of  claim 21 , wherein mating the hardened elongate key to the ESP shaft further comprises mating the rounded top of the arch to a rounded keyway in the sleeve. 
     
     
         23 . The method of  claim 20 , wherein the cross sectional shape of the elongate key is a tee and a cross of the tee is the second side of the hardened elongate key mated to the sleeve. 
     
     
         24 . The method of  claim 23 , wherein mating the hardened elongate key to the ESP shaft further comprises mating a post of the tee to a stepped keyway in the sleeve. 
     
     
         25 . The method of  claim 20 , wherein the carbide composite material comprises a composite material and a carbide, the composite material one of nickel, cobalt or a combination of nickel and cobalt, and wherein the carbide is one of tungsten carbide, silicon carbide or titanium carbide. 
     
     
         26 . The method of  claim 25 , wherein the sleeve is a rotatable member of a bearing set and the sleeve is made of same carbide composite material as the hardened elongate key. 
     
     
         27 . The method of  claim 20 , wherein the cross sectional shape of the elongate key is one of round, arch, tee, asymmetrical tee or L shape and the cross sectional shape of the elongate key optimizes loading zones on the elongate key.