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.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This Application relates claims priority to and the benefit of co-pending United Kingdom Patent Application No. 0811205.4 filed on 19 Jun. 2008, the full disclosure of which is hereby incorporated fay reference.BACKGROUND[0002]1. Field of Invention[0003]The present invention relates to hydraulic intensifiers.[0004]2. Description of Related Art[0005]Hydraulic intensifiers are devices that generate high hydraulic pressure from a low pressure source. When employed in subsea wells such as hydrocarbon production or injection wells, they provide a source of high pressure hydraulic fluid for the operation of hydraulically actuated devices, such as valves and flow control chokes. Such wells are, typically, supplied with low pressure hydraulic fluid via an umbilical, which can be in excess of 100 Km in length. The supply of high pressure fluid via the umbilical is not favoured by well operators, as a high pressure feed within the umbilical, needin...

AI Technical Summary

Benefits of technology

[0008]Disclosed herein is a hydraulic intensifier having a piston and cylinder assembly with 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

Problems solved by technology

The supply of high pressure fluid via the umbilical is not favoured by well operators, as a high pressure feed within the umbilical, needing a much greater wall thickness than usual, results in much greater umbilical and handling costs.

The alternate operation of the piston sets is controlled by a complicated arrangement of valves and springs and since these and the piston sets are integrated into one assembly, current hydraulic intensifiers are complicated devices, which are difficult to manufacture and thus of high cost.

Furthermore, they are heavy devices, typically 37 Kg, and are prone to a multiplicity of problems which include failure of ‘slipper’ seals and changeover valves, sensitivity to contamination and a tendency to ‘lock-up’ due to pressure in their return lines.

Repair requires the complete removal and strip down of the assembly which is also expensive, and new designs require full approval testing before they can be employed.

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