GB2086541A

GB2086541A - Pilot controlled fluid valve

Info

Publication number: GB2086541A
Application number: GB8130917A
Authority: GB
Original assignee: Koomey Inc
Current assignee: Koomey Inc
Priority date: 1980-10-30
Filing date: 1981-10-13
Publication date: 1982-05-12
Also published as: FR2493464A1

Abstract

A pilot controlled valve comprises housing 12 with an inlet port 14, a vent port 16 and a function port 18 which supplies or receives fluid. A valve stem 20 is reciprocable in the housing by a pilot piston 22. First and second tubular valve elements 40, 46 are axially aligned and slideably mounted on the stem 20 for joint and individual movement. The elements 40, 46 are movable for opening and closing the inlet port 14 and the vent port 16 respectively. A spring 52 between the first and second elements 40 and 46 urges both elements towards the closed positions for providing non-interflow between the ports 14, 16. A first shoulder 54 on the stem 20 engages and moves the first element 40 to the open position on movement of the stem in a first direction and a second shoulder 56 on the stem engages and moves the second element 46 to the open position on movement of the stem in a second direction. A piston 62 and cylinder 64 are positioned in the housing 12 with the piston 62 connected to the stem 20 and having a cross-sectional area at least as large as the stem. A passageway 66 is in communication between the cylinder 64 and the interior of the housing 12 through the piston 62 and stem 20 for applying fluid to the piston 62 for compensating for the fluid in the housing acting on the stem 20. <IMAGE>

Description

SPECIFICATION Pilot controlled fluid valve This invention relates to a pilot controlled fluid valve.

It is known from US-PS 3,957,079 to provide a pilot operated fluid valve for controlling the supply to and vent from equipment to be controlled by hydraulic fluid. However, such valves undesirably allow flow between the supply port and the vent port as the valve is actuated. In addition, the high pressure supply fluid acts against the valve stem tending to keep the valve in the open position, thereby requiring undesirably high force pilot controls for closing the valve.

The present invention is directed to an improved pilot controlled fluid valve having means to prevent interflow of fluid.

The present invention provides a non-interflow pilot controlled fluid valve having a housing with an inlet port, a vent port, and a function port for supplying or receiving fluid. A valve stem is movable in the housing and is controlled by suitable pilot control means. First and second valve elements are slideably mounted on the stem with the first element movable for opening and closing the inlet port and the second element is movable for opening and closing the vent port. Yieldably urging means are positioned between the first and second elements for urging the elements towards the closed positions. Shoulder means are provided on the stem for alternately moving the elements toward the open position.

The first and second tubular valve elements are preferably axially aligned and slideably mounted on a valve stem for joint and individual movement.

Spring means may be positioned between the first and second elements for urging both of the elements towards the closed positions for providing noninterflow between the inlet port and the vent port. A first shoulder on the stem engages and moves the first element to the open position on movement of the stem in a first direction and a second shoulder on the stem engages and moves the second element to the open position on movement of the stem in a second direction.

Means may also be provided for compensating for high pressure fluid in the housing acting on the stem. Thus a piston and cylinder may be provided in the housing with the piston being connected to the stem and having a cross-sectional area at least as large as the stem, and preferably larger than the stem, as well as a passageway in communication between the cylinder and the housing interior for applying fluid to the piston in a direction for compensating for the high pressure fluid in the housing acting on the stem. Preferably the passageway is through the piston and the stem.

A presently preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which Figure 1 is an elevational view, in cross section, of a valve according to the present invention in the open position, Figure 2 is a view similar to Figure 1 but with the valve in the closed and venting position, and Figure 3 is an elevational view, partly in cross section, of the valve of Figures 1 and 2 in an intermediate position between the open and closed positions.

Referring now to the drawings, and particularly to Figure 1, non-interflow pilot control fluid valve 10 shown comprises a housing 12 including one or more inlet ports 14 which are adapted to be connected to a hydraulic fluid supply, one or more vent ports 16 for venting fluid, and a function port 18 for supplying hydraulic fluid to an apparatus to be actuated, such as an underwater blowout preventer, or receiving vent fluid therefrom.

A valve stem 20 is reciprocable in the housing 12 and may be actuated by any suitable pilot control means and shown as a piston 22 movable in a cylinder 24 having pilot ports 26 and 28 on opposite sides of the piston 22. Port 26 may be supplied with a hydraulic fluid for acting against the bottom of the piston 22 for moving the valve to an open position.

The port 28 may be a vent port or may receive hydraulic fluid for acting against the top of the piston 22 for closing the valve. The valve may also be closed by providing a spring 30 in the housing 12 positioned between a shoulder 32 in the housing 12 and a shoulder 34 connected to the stem 20. Of course, other suitable pilot control means such as solenoid valves may be utilized if desired.

For preventing interflow between the inlet ports 14 and the vent ports 16 as the valve moves between the open and closed positions a first tubular valve element 40 is provided which is slideably mounted from the stem 20 such as by a support 42. The element 40 is movable in the housing 12 from the open position shown in Figure 1 to a closed position shown in Figure 2 in which the element 40 abuts against a seat 44. With the element 40 in the open position communication of supply fluid through the inlet ports 14 to the function port 18 is permitted, but when the element 40 is in the closed position the supply ports 14 are closed.

A second tubular valve element 46 is axially aligned with the first element 40 and is also slideably mounted on the stem 20 from a support 48. The second element is shown in Figure 1 in a position closing the vent ports 16 by being engaged with a valve seat 50. In Figure 2, the second valve element 46 has been moved by the valve stem 20 away from the seat 50 opening communication between the vent ports 16 and the interior of the body 12 and the function port 18.

Vieldable urging means such as a spring 52 is positioned between the first element 40 and the second element 46 for yieldably urging both of the elements 40 and 46 towards closed positions, as best seen in Figure 3, for preventing fluid interflow between the inlet ports 14 and the vent ports 16. It is noted that the valve elements 40 and 46 are slideably mounted on the stem 20 for joint and individual movement on the stem 20.

Should means are provided on the stem 20 for alternately moving the elements 40 and 46 towards the open positions as the stem 20 is reciprocated by the pilot control means. Thus, a first shoulder 54 is provided on the stem 20 for engaging the support 42 as the stem 20 moves upwardly to carry the first valve element 40 upwardly into an open position-allowing fluid flow from ports 14 to port 18. A second shoulder 56 is provided on the stem 20 for engaging the support 48 as the stem 20 moves downwardly for moving the second element 46 downwardly and into an open position allowing communication of the vent port 16 with the interior of the body 12.

Referring now to Figures 1 and 2, it is noted that the pressure at the function port 18, which is exposed to high operating pressures, acts against the cross-sectional area of the stem 20 within the seal 60 to create a force acting to move the stem 20 upwardly. This requires that the pilot closing mechanism, which may be only the spring 30, have a sufficient force to overcome the fluid force acting on the bottom of the stem 20 in addition to providing the necessary valve closing force. Therefore, in order to compensate for the force on the bottom of the stem 20, a piston 62 is provided movable in a cylinder 64 in the housing 12 in which the crosssectional area of the piston 62 is at least as large as and preferably larger than, the cross-sectional area of the stem 20 moving between the seal 60.In addition, a passageway is provided between the cylinder 64 and in communication with the interior of the housing and the function port 18 such as a passageway 66 through the piston 62 and stem 20 which transmits pressure from the interior of the housing 12 to act against the top of the piston 62 and thus compensate for the fluid force acting upwardly on the stem 20.

Referring now to Figure 1, and in operation, the pilot control mechanism has been actuated to supply fluid to the port 26 to move the piston 22 upwardly carrying the stem 20 upwardly and whereby the shoulder 54 carries first valve element 40 upwardly allowing hydraulic fluid supply to enter the inlet ports 14 and pass to the function port 18. It is also noted that the second valve element 46 is seated on valve seat 50 by the action of the spring 52 and the abutting of first valve element 40 against the second valve element 46 maintains the vent port 16 closed and thereby prevents interflow of hydraulic fluid between the ports 14 and 16. When it is desired to actuate the valve from the open position of Figure 1 to the closed position of Figure 2, the valve first goes through the non-interflow mode of Figure 3.As the pilot control mechanism relieves the pressure from pilot port 26 the piston 22 moves downwardly by applying pilot pressure through port 28 and/or by the spring 30. The action of the spring 52 keeps the vent ports 16 closed and as the shoulder 54 on the stem 20 moves downwardly the spring 52 also causes the first valve element 40 to move downwardly and seat on valve seat 44 before the second valve element 46 unseats from valve seat 50. Therefore, the vent ports 16 do not open until after the inlet ports- 14 are closed. Further downward movement of the valve stem 20 causes the shoulder 56 to engage the valve element 46 moving it downwardly and opening the vents ports 16 whereby hydraulic fluid may be removed from a controlled apparatus and flow upwardly through the function port 18 and out ofthe vent ports 16. The stem 20 moves downwardly until the vent ports 16 are in the fully open position while the first valve element 40 keeps the inlet ports 14 closed, as best seen in Figure 2.

Similarly, when the valve moves from the closed position shown in Figure 2 to the open position shown in Figure 1, the valve goes through the non-interflow mode shown in Figure 3. That is, as the stem 20 and shoulder 56 move upwardly, the spring 52 causes the second valve element 46 to move upwardly until it seats on valve seat 50 to close the vent ports 16. Only after the vent ports 16 are closed, does the shoulder 54 on the stem 20 engage the first valve element 40 and start to open the inlet port 14.

Claims

1. A non-interflow pilot controlled fluid vale comprising a housing having an inlet port, a vent port, and a function port for supplying or receiving fluid, a valve stem movable in said housing, pilot control means for reciprocating said stem, first and second valve elements slideably mounted on the stem, said first element being movable for opening and closing the inlet port, and said second element being movable for opening and closing the vent port, yieldably urging means positioned between the first and second elements for urging said elements toward the closed positions, and shoulder means on the stem for alternately moving said elements toward the open position.

2. A valve according to Claim 1 including spring means in the housing for urging the stem in a direction for closing the inlet port.

3. A valve according to Claim 1 including a piston and cylinder in the housing, said piston being connected to the stem and having a larger crosssectional area than the stem, and a passageway in communication between the cylinder and the function port for applying fluid to the piston in a direction for urging the stem in a direction for closing the inlet port.

4. A non-interflow pilot controlled fluid valve comprising a housing having an inlet port, a vent port and function port for supplying or receiving fluid, a valve stem movable in said housing, pilot control means for reciprocating said stem, first and second tubular valve elements axially aligned and slideably mounted on the stem for joint and individual movement, said first element being movable for opening and closing the inlet port and said second element being movable for opening and closing the vent port, said spring means positioned between the first and second elements for urging both of said elements toward the closed positions for providing non-interflow between the inlet port and the vent port, a first shoulder on the stem for engaging and moving the first element to the open position on movement of the stem in a first direction, and a second shoulder on the stem for engaging and moving the second element to the open position on movement of the stem in a second direction.

5. A valve according to Claim 4 including, a piston an cylinder in the housing, said piston being connected to the stem and having a cross-sectional area at least as large as the stem, and a passageway in communication between the cylinder and the function port for applying fluid to the piston in a direction for compensating for the fluid acting on the stem.

6. A valve according to Claim 5 wherein the passageway is through the piston and the stem.

7. A valve according to Claim 6 wherein the cross-sectional area of the piston is greater than the cross-sectional area of the stem on which the fluid at the function port acts.

8. A valve according to Claim 4 wherein said first and second tubular valve elements abut each other at the extent of movement in said first and second directions.

9. A non-interflow pilot controlled fluid valve substantially as hereinbefore described with reference to the accompanying drawings.