Hydraulic intensifiers

Abstract

A hydraulic intensifier with a piston and cylinder assembly ( 1 ) having a first piston ( 3 ) in a chamber ( 4 ) of low pressure cylinder and a second piston ( 7 ) in a chamber ( 8 ) of a high pressure cylinder. The first and second pistons are coupled together and the first piston has a larger cross-sectional area than the second piston. A high pressure output ( 19 ) is coupled to the chamber of the high pressure cylinder, there being; means ( 13 ) for supplying low pressure hydraulic fluid to the chamber of the low pressure cylinder; an electrically operated directional control valve ( 11 ) for controlling the supply of low pressure hydraulic fluid to the chamber of the low pressure cylinder; and electronic means ( 14 ) for controlling operation of the directional control valve.

1 . A hydraulic intensifier comprising:
 a piston and cylinder assembly having a first piston in a chamber of a low pressure cylinder and a second piston in a chamber of a high pressure cylinder, the first and second pistons being coupled together and the first piston having a larger cross-sectional area than the second piston;   a high pressure output coupled to the chamber of the high pressure cylinder;   a low pressure hydraulic fluid supply in fluid communication with the chamber of the low pressure cylinder; and   an energizable directional control valve in selective fluid communication with the low pressure hydraulic fluid supply, in selective fluid communication with the chamber of the low pressure cylinder, and in selective fluid communication with the, so that when the directional control valve is energized the low pressure fluid supply and low pressure cylinder chamber are in fluid communication.   
   
   
       2 . A hydraulic intensifier according to  claim 1 , comprising:
 a second piston and cylinder assembly, the high pressure output being coupled to the chamber of the high pressure cylinder of the second piston and cylinder assembly; and   a second directional control valve having a side in fluid communication with the low pressure hydraulic fluid supply and a side in fluid communication with the chamber of die second low pressure cylinder, so that when the directional control valve is energized the low pressure fluid supply and the second low pressure cylinder chamber are in fluid communication.   
   
   
       3 . A hydraulic intensifier comprising:
 a first piston and cylinder assembly having a first piston in a chamber of a low pressure cylinder and a second piston in a chamber of a high pressure cylinder, the first and second pistons being coupled together and the first piston having a larger cross-sectional area than the second piston;   a second piston and cylinder assembly;   a high pressure output coupled to the chambers of the high pressure cylinders of the first and second piston and cylinder assemblies;   means for supplying low pressure hydraulic fluid to the chambers of the low pressure cylinders of the first and second piston and cylinder assemblies;   first and second electrically operated directional control valves for controlling the supply of low pressure hydraulic fluid to the chambers of the low pressure cylinders of the first and second piston and cylinder assemblies respectively; and   electronic means for controlling operation of the directional control valves to supply low pressure hydraulic fluid alternately to the chambers of said low pressure cylinders.   
   
   
       4 . A hydraulic intensifier according to  claim 3 , wherein low pressure hydraulic fluid is supplied to the chambers of the high pressure cylinders via respective ones of first and second check valves, said chambers of the high pressure cylinders being coupled with said high pressure output via respective ones of third and fourth check valves. 
   
   
       5 . A hydraulic intensifier according to  claim 1 , comprising means coupled to said electronic means for sensing pressure of hydraulic fluid at said high pressure output and causing the or each directional control valve not to supply hydraulic fluid to the chamber or chambers of the low-pressure cylinder or cylinders in response to the sensed pressure being at a required value. 
   
   
       6 . A hydraulic intensifier according to  claim 3 , comprising means coupled to said electronic means for sensing pressure of hydraulic fluid at said high, pressure output and causing the or each directional control valve not to supply hydraulic fluid to the chamber or chambers of the low pressure cylinder or cylinders in response to the sensed pressure being at a required value. 
   
   
       7 . A hydraulic intensifier according to  claim 1 , wherein said electronic means comprises a bistable device. 
   
   
       8 . A hydraulic intensifier according to  claim 3 , wherein said electronic means comprises a bistable device. 
   
   
       9 . A hydraulic intensifier according to  claim 1 , comprising a hydraulic accumulator coupled with said high pressure output. 
   
   
       10 . A hydraulic intensifier according to  claim 3 , comprising a hydraulic accumulator coupled with said high pressure output. 
   
   
       11 . A hydraulic intensifier according to  claim 1 , adapted for use in a subsea well. 
   
   
       12 . A hydraulic intensifier according to  claim 3 , adapted for use in a subsea well. 
   
   
       13 . A hydraulic intensifier according to  claim 1 , wherein said electronic means is provided via a subsea electronics module for a subsea well. 
   
   
       14 . A hydraulic intensifier according to  claim 3 , wherein said electronic means is provided via a subsea electronics module for a subsea well. 
   
   
       15 . A hydraulic intensifier according to  claim 11 , wherein the or each directional control value is provided by a directional control valve of a subsea control module for a subsea well. 
   
   
       16 . A hydraulic intensifier according to  claim 12 , wherein the or each directional control value is provided by a directional control valve of a subsea control module for a subsea well. 
   
   
       17 . A method of producing high pressure hydraulic fluid comprising:
 providing a piston and cylinder assembly having a first piston in a chamber of low pressure cylinder and a second piston in a chamber of a high pressure cylinder, the first and second pistons being coupled together, the first piston having a larger cross-sectional area than the second piston and there being a high pressure output coupled to the chamber of the high pressure cylinder;   supplying low pressure hydraulic fluid to the chamber of the low pressure cylinder;   providing an electrically operated directional control valve for controlling the supply of low pressure hydraulic fluid to the chamber of the low pressure cylinder; and   electronically controlling operation of the directional control valve.   
   
   
       18 . A method according to  claim 17 , comprising:
 providing a second piston and cylinder assembly, the high pressure output being coupled to the chamber of the high pressure cylinder of the second piston and cylinder assembly;   providing a second such directional control valve for controlling supply of low pressure fluid to the chamber of the low pressure cylinder of the second piston and cylinder assembly; and   electronically controlling the directional control valves to supply low pressure fluid alternately to the chambers of the low pressure cylinders of the first and second piston and cylinder assemblies.