Patent Application
20060096645
The invention relates to directional control valves. The invention more specifically relates to a hydraulic directional control valve operated by an electric solenoid without a pilot valve stage as may be required for a subsea production control system, further comprising a fail safe latch.
Electro-hydraulic operated valves are used subsea. Referring to
A pilot valve, e.g 102a,102b, often consists of many small, complex parts, comprising small pieces and narrow fluid passages. In these configurations, problems may exist as a result of using a pilot valve stage, including leaking and clogging. Either or both of these problems reduce the effectiveness of the overall valve assembly. Valve assemblies that do not incorporate a pilot valve stage would not have these problems.
The features, aspects, and advantages of the present invention will become more fully apparent from the following description, appended claims, and accompanying drawings in which:
Referring generally to
In a preferred embodiment, hydraulic directional control valve 202 further comprises a latch mechanism, as described in more detail herein below, e.g. for a fail safe latch out function, and may comprise a pulse operated, shear type seal valve.
As described herein below in more detail and referring generally to
Electric actuator 210 may comprise an electric solenoid, an electric motor, or the like, or a combination thereof, and is preferably a double acting electrically actuable solenoid. Further, as used herein, those of ordinary skill in the art will understand that solenoid 19, when described as moving, means that the moving portion of solenoid 19 is that which moves, not the entire solenoid which may further comprise windings, a housing, and the like.
Referring still to
As noted above, electric actuator 210 is preferably a double or dual acting electrically actuable solenoid 19 and may be disposed at a first end of housing 01.
Cover 03 may be sealingly disposed at a second end of housing 01 and may be removably secured to the second end of housing 01, e.g. by socket screw 58, or permanently secured to the second end of housing 01.
Additionally, one or more seals 44 may be disposed in a sealing relation between cover 03 and housing 01.
Supply pressure port 71 defines a first passageway to slide 04 from the exterior of housing 01 and a second passageway 75 from the first passageway into housing annulus 06. Return line port 72 defines a passageway into housing annulus 06 from the exterior of housing 01. Function line port 74 defines a passageway to slide 04 from the exterior of housing 01. Internal bore 76 defines a passageway between housing annulus 06 on each side of free moving piston 10.
Piston 10 is typically slidably disposed within housing annulus 06, intermediate cover 03 and slide 04. Spring 11 may be disposed within housing annulus 06 intermediate cover 03 and piston 10. In this configuration, spring 11 is adapted to communicate with both piston 10 and cover 03 to urge piston 10 towards slide 04 and bring the hydraulic directional control valve to a safe position.
Washer 12 may be used for supporting and/or fixing spring 11. Washer 12 may further be used to aid in adjusting spring force exerted by spring 11 such as by increasing or decreasing the thickness of washer 12 prior to its installation. Spring 11 may be used to oppose the pressure force from latch piston 10 and frictional forces in the shear type seal valve and bring slide 04 to a safe position if the supply pressure falls below a predetermined pressure level.
Function line port 74 may be disposed within slide 04 where function line port 74 is adapted to be in fluid communication with supply pressure port 71, return line 72, or both. One or more spacers 07 may be disposed within supply pressure port 71.
Slide 04 may be disposed within housing annulus 06 intermediate and in communication with the moving portion of solenoid 19 and latch piston 10 and may further comprise function line port 74. In a preferred embodiment, slide 04 is a shear type seal slide. Seats, e.g. supply seat 05P and function port seat 05A, may be disposed within housing 01 in communication with slide 04 to form a seal. In a preferred embodiment, supply seat 05P and function port seat 05A are shear type seal seats. One or more packings 31 may be disposed about a circumference of supply seat 05P and function port seat 05A, sealing off the line pressures against the housing annulus 06 pressure.
Latch piston 10 may further comprise a shoulder where a portion of spring 11, e.g. an end portion, is in communication with the shoulder. Washer 12 may further be disposed intermediate the shoulder and the end portion of spring 11. Washer 13 may be present proximate the opposite end portion of spring 11, intermediate spring 11 and cover 03. One or more packings, e.g. U-packings 32 and 33, may be disposed about an outer circumference of latch piston 10 opposite the shoulder where the packings are in communication with the exposed circumference of the housing annulus 06.
One or more socket screws 58 may be disposed within cover 03 disposed at second end of housing 01. One or more seals 44, which may be of the type generally known in the art such as an O-ring, may be present to seal cover 03 from housing annulus 06.
Springs 08 within each chamber urge supply seat 05P and function port seat 05A against slide 04. Spacer 07 may additionally exist in the chambers and be in communication with supply port seat 05P.
One or more seals 44 may be present and disposed in a sealing relation between cover 03 and housing 01.
In the operation of a preferred embodiment, hydraulic directional control valve assembly 200 is typically a three-way, two-position valve, i.e. there are three connected ports configured such that fluid flow can go in one of two paths, e.g. from supply pressure port 71 through function port 74 or from function port 74 through return port 72.
In a typical configuration, supply pressure port 71 is connected to an external supply pressure source (not shown in the figures). Function line port 74 is connected to an external spring return hydraulic actuator (not shown in the figures). Return line port 72 is connected to an external return line (not shown in the figures).
Typically, before any hydraulic pressure or electric power is applied to hydraulic directional control valve assembly 200, slide 04 is resting in a “closed” position, as forced by spring 11. Pressure is applied on supply pressure port 71, e.g. from a fluid line. Fluid under pressure enters housing annulus 06, resulting in a fluid force being applied on a differential area between two U-packings 32, 33. The fluid force moves latch piston 10 as the fluid force overcomes the force of spring 11. This helps ensure that latch piston 10 and spring 11 are completely removed from influencing slide 04 and solenoid 19. The latch function will therefore be “invisible” during normal operation as long as the supply pressure is above a predetermined “fail safe level.” Above the predetermined “fail safe level,” hydraulic directional control valve assembly 200 can be pulse operated.
Referring additionally to
When the electric pulse is stopped, slide 04 may remain in the “open” position due to the frictional forces between slide 04 and supply seat 05P and function port seat 05A.
Referring additionally to
If, when the slide is in the open position, the supply pressure falls below the predetermined fail safe pressure, the spring force from spring 11 overcomes the latch piston force and the frictional force between slide 04, supply seat 05P, and function port seat 05A and moves latch piston 10, slide 04, and solenoid 19 over to the “closed” position. When the slide is in the “closed” position, fluid flow, as described above, is directed out return line port 72, bringing the external hydraulic actuator to a fail safe position.
It will be understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated above in order to explain the nature of this invention may be made by those skilled in the art without departing from the principle and scope of the invention as recited in the following claims.
