Constant environment subsea control system

Abstract

The method of providing a pressurized control fluid for the operation of subsea equipment of providing an accumulator with control fluid pressurized by compressed gas, supplying the control fluid to a control valve for the purpose of operating a function, receiving a return flow of the control fluid from the function to a control valve, directing the return flow of the control fluid to a low pressure chamber whose pressure is substantially unaffected by the subsea environmental pressure, and maintaining the low pressure level in the low pressure chamber.

1 . The method of providing a pressurized control fluid for the operation of subsea equipment comprising:
 providing an accumulator with control fluid pressurized by compressed gas,   supplying said control fluid to a control valve for the purpose of operating a function,   receiving a return flow of said control fluid from said function,   directing said return flow of said control fluid to a chamber whose pressure is substantially unaffected by the subsea environmental pressure.   
     
     
         2 . The method of  claim 1 , further comprising pumping the fluids out of said low pressure reservoir. 
     
     
         3 . The method of  claim 2 , further comprising pumping said fluids into the ocean water. 
     
     
         4 . The method of  claim 2 , further comprising pumping said fluids back to the surface. 
     
     
         5 . The method of  claim 4 , further comprising that the hose which returns said fluids back to the surface is the same hose which brought said fluids down from the surface. 
     
     
         6 . The method of  claim 1 , further comprising flooding said low pressure reservoir with water to sweep any accumulated gas out of said low pressure reservoir. 
     
     
         7 . The method of  claim 6 , further comprising said water to sweep said accumulate gas is control fluid from the surface. 
     
     
         8 . The method of  claim 6 , further comprising said water to sweep said accumulate gas is sea water. 
     
     
         9 . The method of  claim 8 , further comprising said sea water to sweep said accumulate gas is pumped by the same pump which will pump fluids out of said reservoir. 
     
     
         10 . The method of  claim 8 , further comprising said sea water to sweep said accumulate gas is pumped by a different pump than the pump which pumps fluids out of said reservoir. 
     
     
         11 . The method of providing a pressurized control fluid for the operation of subsea equipment comprising:
 providing an accumulator with control fluid pressurized by compressed gas,   supplying said control fluid to a control valve for the purpose of operating a function,   receiving a return flow of said control fluid from said function to a control valve,   directing said return flow of said control fluid to a chamber whose pressure is substantially unaffected by the subsea environmental pressure.   
     
     
         12 . The method of  claim 11 , further comprising pumping the fluids out of said low pressure reservoir. 
     
     
         13 . The method of  claim 12 , further comprising pumping said fluids into the ocean water. 
     
     
         14 . The method of  claim 12 , further comprising pumping said fluids back to the surface. 
     
     
         15 . The method of  claim 14 , further comprising that the hose which returns said fluids back to the surface is the same hose which brought said fluids down from the surface. 
     
     
         16 . The method of  claim 11 , further comprising flooding said low pressure reservoir with water to sweep any accumulated gas out of said low pressure reservoir. 
     
     
         17 . The method of  claim 16 , further comprising said water to sweep said accumulate gas is control fluid from the surface. 
     
     
         18 . The method of  claim 16 , further comprising said water to sweep said accumulate gas is sea water. 
     
     
         19 . The method of  claim 18 , further comprising said sea water to sweep said accumulate gas is pumped by the same pump which will pump fluids out of said reservoir. 
     
     
         20 . The method of  claim 18 , further comprising said sea water to sweep said accumulate gas is pumped by a different pump than the pump which pumps fluids out of said reservoir.