Pressure Compensated Rotating Electrical Contact

Abstract

A technique facilitates communication of electrical signals in harsh environments and between components that undergo relative rotation with respect to each other. The technique comprises rotatably mounting a first component with respect to a second component. The first component also is electrically coupled with the second component via an electrical coupler. The electrical coupler may comprise a first electrical contact located at the first component and a second electrical contact located at the second component. The first electrical contact is conductively connected with the second electrical contact via a conductive bearing. The conductive bearing is located in a volume which is filled with a substantially incompressible fluid to protect the bearing.

What is claimed is: 
     
         1 . A system for use in a well, comprising:
 a well string having a first component, a second component, and an electrical coupler for conducting electric current between the first component and the second component, the first component being rotatable with respect to the second component, the electrical coupler comprising:
 a first electrical contact positioned in the first component; 
 a second electrical contact positioned in the second component; 
 a bearing formed of conductive material and mounted between the first component and the second component, the bearing being formed of a ii conductive material and being located in a cavity between the first component and the second component; and 
 a substantially incompressible fluid disposed in the cavity. 
   
     
     
         2 . The system as recited in  claim 1 , wherein pressure equalizes between the cavity and an exterior region outside of the cavity. 
     
     
         3 . The system as recited in  claim 2 , wherein the substantially incompressible fluid comprises a grease. 
     
     
         4 . The system as recited in  claim 3 , wherein the first component comprises a shaft. 
     
     
         5 . The system as recited in  claim 4 , wherein the bearing comprises a first race mounted against the first component in contact with the first electrical contact, a second race mounted against the second component in contact with the second electrical contact; and a plurality of conductive contact elements rotatably trapped s between the first race and the second race. 
     
     
         6 . The system as recited in  claim 2 , wherein the pressure equalizes through a porous gland material placed between the first component and the second component. 
     
     
         7 . The system as recited in  claim 6 , wherein the porous gland material contains a fluid. 
     
     
         8 . The system as recited in  claim 2 , wherein the pressure equalizes through a porous material located in at least one of the first component or the second component. 
     
     
         9 . The system as recited in  claim 2 , wherein the second component is formed of a porous material and further wherein the pressure equalizes through the porous material. 
     
     
         10 . The system as recited in  claim 2 , wherein the first component is formed of a porous material and further wherein the pressure equalizes through the porous material. 
     
     
         11 . A method, comprising:
 rotatably mounting a first component with respect to a second component;   locating a first electrical contact at the first component and a second electrical contact at the second component;   conductively connecting the first electrical contact and the second electrical contact via a conductive bearing; and   filling a volume around at least a portion of the conductive bearing with a substantially incompressible fluid.   
     
     
         12 . The method as recited in  claim 11 , wherein rotatably mounting comprises rotatably mounting first and second well components. 
     
     
         13 . The method as recited in  claim 12 , wherein conductively connecting comprises connecting via the conductive bearing by engaging a first race of the conductive bearing with the first component, engaging a second race of the conductive bearing with the second component, and rotatably capturing a plurality of the conductive rotatable members between the first race and the second race such that electricity may be conducted through the first race, the plurality of conductive rotatable members, and the second race. 
     
     
         14 . The method as recited in  claim 13 , wherein filling the volume comprises filling the volume with a grease. 
     
     
         15 . The method as recited in  claim 13 , further comprising equalizing pressure between an exterior region and the volume via a porous material. 
     
     
         16 . The method as recited in  claim 15 , further comprising using the porous material to prevent movement of particulates into the volume. 
     
     
         17 . The method as recited in  claim 12 , further comprising moving the first component and the second component downhole into a wellbore and removing heat generated by the ball bearing via flow of a well fluid. 
     
     
         18 . A system for communicating electrical signals, comprising:
 a first component rotatably mounted with respect to a second component;   a first electrical contact located at the first component and a second electrical contact located at the second component, the first electrical contact being operatively coupled with the second electrical contact via a conductive bearing, the conductive bearing having a plurality of rotatable members which rotate during rotation of the first component with respect to the second component; and   a housing creating a volume around at least a portion of the conductive bearing, the volume being filled with a substantially incompressible fluid.   
     
     
         19 . The system as recited in  claim 18 , wherein the first component and the second component are downhole well components. 
     
     
         20 . The method as recited in  claim 18 , wherein the conductive bearing comprises a first race engaged with the first component, a second race engaged with the second component, wherein the plurality of rotatable members are rotatably trapped between the first race and the second race such that electricity may be conducted through the first race, the plurality of rotatable members, and the second race.