GB2209561A

GB2209561A - Remotely controllable hydraulic power source

Info

Publication number: GB2209561A
Application number: GB8721081A
Authority: GB
Inventors: Roy Franklin Williams; Malcolm Paul
Original assignee: Royal Ordnance PLC
Current assignee: BAE Systems Global Combat Systems Munitions Ltd
Priority date: 1987-09-08
Filing date: 1987-09-08
Publication date: 1989-05-17
Anticipated expiration: 2007-09-08
Also published as: GB2209561B; GB8721081D0

Abstract

A remotely controllable hydraulic power source comprises a hydraulic accumulator having an input line for pressurised gas and an output line for hydraulic power fluid, means for connecting the output line to a hydraulically actuated device, a remotely controllable valve for controlling the flow of hydraulic power fluid in the output line, and means connected to the input line to maintain the gas pressure in the accumulator within a predetermined range. <IMAGE>

Description

REMOTELY CONTROLLABLE HYDRAULIC POWER SOURCE This invention relates to the remote control of a hydraulically-actuated device.

In certain applications there arises a need to operate a hydraulically actuated device at a considerable distance from a control station. One particluar example occurs in the extraction of oil or gas from below the sea bed, when there can often be a need to control quite a large number of pipeline valves situated at the well head, from a control station which my be situated at a distance of 10km or more.

Conventional practice in such circumstances is to provide a hydraulic power line from the control station to each remote hydraulic device. The line thus transmits the control signal as well as the hydraulic power required to effect the desired operation. The remote control of a single pipeline valve at the well head may thus require the provision of over 10km of hydraulic line dedicated to the control and operation of that one valve. The provision of such a considerable length of hydraulic line, and its maintenance on the seabed, are extremely costly.

The present invention therefore seeks to provide a means for enabling the remote control of a hydraulically actuated device such as a valve for an underwater pipeline, which does not require the provision of a hydraulic line connecting the device to a control station.

Accordingly the present invention provides a remotely controllable hydraulic power source, comprising a hydraulic accumulator having an input line for pressurised gas and an output line for hydraulic power fluid, means for connecting the output line to a hydraulically actuated device, a remotely controllable valve for controlling the flow of hydraulic power fluid in the output line, and means connected to the input line to maintain the gas pressure in the accumulator within a predetermined range.

Most appropriately the hydraulically actuated device is a valve for controlling the fluid flow in an underwater pipeline.

The remotely controllable valve may be a solenoid-actuated valve which may be controlled from a remote control station for example by a radio link or through an electrical cable connection thereto.

The means for generating pressurised gas may most conveniently comprise a pressurisable source of hydrazine and a catalyst for causing the chemical decomposition of hydrazine into ammonia and hydrogen.

Preferably the power supply is mounted on a unitary mounting and is thus self-contained.

The invention will now be described by way of example only with reference to the accompanying drawings, of which Figure 1 is a diagrammatic perspective view of a remotely controllable hydraulic power supply in accordance with the invention, and Figure 2 is a hydraulic line diagram showing the hydraulic circuit thereof in greater detail, and its connection to an underwater pipeline valve.

As shown in Figure 1, a remotely controllable hydraulic power source comprises a mounting pallet 1 provided with a pair of lifting rings 2.

As shown in greater detail in Figure 2, the power source comprises a supply of hydrazine contained in a vessel 3, in which it is maintained under pressure by nitrogen gas contained in a vessel 4. The nitrogen is at high pressure, and is connected to the hydrazine vessel 3 through a pressure and flow regulation 5 and a non-return valve 6. Also interposed in the line between the vessels 3 and 4 is a remotely-controllable solenoid-operated valve 7 which can open and close the line connecting the vessels 3 and 4, and in a third position can vent the nitrogen-containing side of the vessel 3 to atmosphere while closing the outlet of the vessel 4. In this latter condition of the valve 7, the power source is rendered safe for transport and re-charging as described hereinafter. The vessel 3 contains a movable diaphragm 8 for keeping the nitrogen and hydrazine separate.

Hydrazine can be expelled from the vessel 3 under the pressure of nitrogen, and passes thence into a gas generator 9 containing a catalyst 10 which causes the chemical decomposition of hydrazine into large volumes of hydrogen and ammonia. This gaseous product passes through a molecular sieve 11 which absorbs the ammonia produced, and thence via a non-return valve 12 into a hydraulic accumulator 13. The accumulator 13 contains a supply of hydraulic oil 14, and floating piston 15 which separates the oil 14 from the pressurised hydrogen gas supplied via the molecular sieve 11. The position of the piston is indicative of the quantity of oil 14 remaining in the accumulator, and this is shown by means of a piston position indicator 16.

For the purpose of maintaining the oil pressure within the accumulator 13 within a desired range, a pressure switch 17 is interposed in the line between the gas generator 9 and the molecular sieve 11, and a solenoid operated valve 18 is interposed between the hydrazine vessel 3 and the gas generator 9. When the pressure in the accumulator 13 falls to a predetermined minimum, the pressure switch 17 sends a signal via an eletrical connection 19 to cause the valve 18 to open. Hydrazine thus flows to the gas generator 9, thence to supply pressurised gas to the accumulator 13 until the switch 17 senses that a predetermined maximum pressure has been reached; at this stage the switch 17 sends a signal to close the valve 18. A gauge 20 may be provided to indicate the pressure in the accumulator 13.

By means of respective self-sealing bayonet connectors 21, 22 the nitrogen vessel 4 and the hydrazine vessel 3 can be recharged when necessary, the valve 7 being moved to the third position hereinbefore described for the safety of the personnel when moving the power supply or carrying out recharging. The accumulator 13 can be recharged when desired by means not shown. Recharging can be carried out in situ by a driver, or the pallet 1 carrying the hydraulic power supply can be recovered to the surface - a spare fully charged unit preferably being kept to replace a unit which is removed.

The need for recharging can be remotely sensed - eg by monitoring the pressure and/or piston position in the accumulator 13; the pressure of nitrogen in the vessel A, and the volume of hydrazine in the vessel 3 might also be sensed remotely.

By means thus far described, a supply of hyrdraulic power fluid can be maintained at the outlet 23 of the accumulator 13. The outlet 23 is connected to a line 24, and is controlled by an electrical solenoid-operated valve 25. The valve 25 is controlled from a remote station (not shown), for example by means of a radio control link or by means of an electrical cable connection. In any case, the need for a hydraulic line linking the valve 25 to a control station is avoided.

The valve 25 is a double-acting valve and controls a piston 26. In a first condition, the valve 25 supplies high pressure hydraulic fluid from the line 24 to the upper side of the piston 26 via line 27. The lower side of the piston is vented to atmosphere via lines 28 and 29. The piston 26 is thus moved downwardly to close a valve 30 which controls fluid flow in an underwater pipeline 31.

In a second condition, the valve 25 supplies high pressure fluid from the line 24 to the lower side of the piston 26 via line 28, the vent via line 29 being closed.

Instead, the upper side of the piston can now vent to atmosphere via lines 27 and 32. The piston 26 is thus moved upwardly to open the valve 30.

Although the remotely controllable hydraulic power source has been described as operating a valve in an underwater pipeline, it will be appreciated that the invention can equally be used for the remote control of other hydraulically operated devices, whether or not underwater.

Claims

1. A remotely controllable hydraulic power source comprising a hydraulic accumulator having an input line for pressurised gas and an output line for hydraulic power fluid, means for connecting the output line to a hydraulically actuated device, a remotely controllable valve for controlling the flow of hydraulic power fluid in the output line, and means connected to the input line to maintain the gas pressure in the accumulator within a predetermined range.

2. A remotely controllable hydraulic power source according to claim 1 wherein the hydraulically actuated device is a valve for controlling the fluid flow in an underwater pipeline.

3. A remotely controllable hydraulic power source according to claim 1 or claim 2 wherein the remotely controllable valve is a solenoid-actuated valve controllable by radio link or through an electrical cable connection.

4. A remotely controllable hydraulic power source according to any one preceding claim wherein the means for generating pressurised gas comprises a pressurisable source of hydrazine and a catalyst for causing the chemical decomposition of hydrazine into ammonia and hydrogen.

5. A remotely controllable hydraulic power source according to any one preceding claim mounted on a unitary mounting and thus being self-contained.

6. A remotely controllable hydraulic power source substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.