Purging fluid circuits in wellbore control devices

Abstract

The disclosure relates to purging a RCD including a bearing of contaminants with a fluid circuit, the fluid circuit having at least one housing adjacent to the RCD, a first plurality of valves within the bearing, a second plurality of valves within the housing, at least one inlet port located on the RCD, each inlet port being connected to the housing, at least one outlet port located on the RCD, each outlet port being connected to the housing, and a purge outlet in fluid communication with the fluid circuit.

What is claimed is: 
     
         1 . An apparatus for purging a RCD containing a bearing with a fluid circuit, the fluid circuit comprising:
 at least one housing adjacent to the RCD;   a first plurality of valves within the bearing;   a second plurality of valves within the housing;   at least one inlet port located on the RCD, each inlet port being connected to the housing;   at least one outlet port located on the RCD, each outlet port being connected to the housing; and   a purge outlet in fluid communication with the fluid circuit.   
     
     
         2 . The apparatus as claimed in  claim 1 , further comprising a hydraulic line in fluid communication with the fluid circuit, wherein the hydraulic line is routed through the second plurality of valves within the housing. 
     
     
         3 . The apparatus as claimed in  claim 2 , wherein the first plurality of valves within the bearing is in a closed position during purging of the RCD. 
     
     
         4 . The apparatus as claimed in  claim 3 , further comprising:
 one or more journal regions located between the bearing and the RCD, wherein the journal regions are in fluid communication with the hydraulic line and further wherein the journal regions are configured to capture debris.   
     
     
         5 . The apparatus as claimed in  claim 4 , wherein the one or more inlet ports are in fluid communication with the fluid circuit, each inlet port connecting the housing and the journal regions; and further wherein the one or more outlet ports are in fluid communication with the fluid circuit, each outlet port connecting to the housing and the journal regions. 
     
     
         6 . The apparatus as claimed in  claim 5 , wherein the hydraulic line further comprises:
 a supply line connected to the fluid circuit;   a bleed line connected to the fluid circuit; and   a return line connected to the fluid circuit.   
     
     
         7 . The apparatus as claimed in  claim 6 , further comprising a directional control valve, wherein the directional control valve is configured to allow redirection of fluid flow from the supply line to the bleed line. 
     
     
         8 . The apparatus as claimed in  claim 1 , wherein the fluid circuit is a lubricating fluid circuit of the RCD, and further wherein the first plurality of valves within the bearing is configured to be in an open position during lubrication of the bearing. 
     
     
         9 . The apparatus as claimed in  claim 1 , wherein the at least one housing is attached to the RCD. 
     
     
         10 . The apparatus as claimed in  claim 1 , wherein the second plurality of valves is pilot-operated check valves. 
     
     
         11 . A system for purging contaminants from a lubricating circuit of a RCD using a purge fluid, comprising:
 at least one valve block adjacent to the RCD;   a plurality of valves housed within the valve block, said plurality of valves configured for controlling a fluid flow; and   at least one hydraulic line routed through the plurality of valves and the RCD.   
     
     
         12 . The system as claimed in  claim 11 , further comprising a pump connected to the hydraulic line, wherein the pump is configured for pumping the purge fluid. 
     
     
         13 . The system as claimed in  claim 12  wherein the at least one hydraulic line comprises a supply line attached to the pump configured for supplying the purge fluid to the RCD. 
     
     
         14 . The system as claimed in  claim 13 , wherein the at least one hydraulic line further comprises a hydraulic line configured for removing contaminants and the purge fluid from the RCD. 
     
     
         15 . The system as claimed in  claim 14 , further comprising:
 a bearing within the RCD; and   one or more journal regions between the bearing and the RCD.   
     
     
         16 . The system as claimed in  claim 15 , wherein the plurality of valves is further configured to control the fluid flow around the journal regions to remove contaminants. 
     
     
         17 . The system as claimed in  claim 16 , wherein the supply line is configured to supply the purge fluid through the plurality of valves in the valve block to the journal regions. 
     
     
         18 . The system as claimed in  claim 17 , wherein the purge fluid is a lubricating and cooling fluid. 
     
     
         19 . A method of purging a RCD containing a bearing with a fluid circuit containing a first plurality of valves, comprising the steps of:
 pumping a purge fluid through a housing containing a second plurality of valves;   circulating the purge fluid from the housing around the bearing with the fluid circuit; and   emptying the purge fluid from the RCD after the purge fluid exits the RCD.   
     
     
         20 . The method as claimed in  claim 19 , further comprising the steps of controlling the purge fluid with the first and second plurality of valves. 
     
     
         21 . The method as claimed in  claim 20 , wherein the step of circulating the purge fluid through the housing also comprises removing contaminants, and further wherein the step of emptying the purge fluid from the RCD after the purge fluid exits the RCD also comprises emptying the contaminants from the RCD after the purge fluid and the contaminants exit the RCD. 
     
     
         22 . The method as claimed in  claim 21 , further comprising the step of preventing the flow of fluid through the first plurality of valves in the fluid circuit. 
     
     
         23 . The method as claimed in  claim 19 , wherein the fluid circuit is a pre-existing cooling and lubricating fluid circuit for the RCD;
 wherein said step of pumping the purge fluid through the housing is performed utilizing the pre-existing cooling and lubricating fluid circuit; and   wherein said step of circulating the purge fluid from the housing is performed utilizing the pre-existing cooling and lubricating fluid circuit.   
     
     
         24 . The method as claimed in  claim 23 , wherein the pre-existing cooling and lubricating fluid circuit has at least a hydraulic supply line, a hydraulic bleed line and a hydraulic return line, and further wherein the step of pumping the purge fluid through the housing further comprises the steps of:
 pumping the purge fluid into the supply line; and   redirecting the purge fluid from the supply line into the bleed line.   
     
     
         25 . The method as claimed in  claim 23 , further comprising the step of preparing the RCD for a subsequent lubrication cycle. 
     
     
         26 . The method as claimed in  claim 19 , wherein the step of circulating the purge fluid from the housing around the bearing comprises circulating the purge fluid through a journal region between the bearing and the RCD. 
     
     
         27 . The method as claimed in  claim 19 , wherein the step of circulating the purge fluid from the housing around the bearing with the fluid circuit also comprises the step of cooling the bearing as the purge fluid circulates around the bearing. 
     
     
         28 . A method of purging contaminants from a RCD comprising the steps of:
 utilizing a preexisting fluid circuit having at least a hydraulic supply line and a hydraulic return line;   pumping a purge fluid with an existing pump into the supply line;   redirecting the purge fluid to another line;   moving the purge fluid in a unitary direction through at least one RCD towards a purge outlet; and   dumping the contaminants via the purge outlet.