GB2133118A - Quick fluid exhaust valve - Google Patents

Abstract

A quick fluid exhaust valve 10 comprises a housing 12 with a chamber 14 and an inlet port 16 outlet port 18 and vent port 20 in communication with the chamber. An internal valve assembly 30 sealingly moves in the chamber and includes a valve element 32 with a face seal 34 for seating on a vent valve seat 28 for closing the vent. The assembly 30 includes a passageway 36 for providing communication from the inlet port 16 to the outlet port 18. An outlet port valve element 40 is slidably positioned on the assembly and includes a face seal 42 for seating on an outlet valve seat 38 with spring means 44 urging the outlet port element into a closing position. The assembly 30 is exposed to pressure at the inlet port 16 which acts on the assembly to close the vent port and the assembly is exposed to the pressure at the outlet port 18, whereby when the inlet port pressure decreases the pressure at the outlet port 18 will act on the assembly 30 and the outlet valve element to close the passageway 36 and open the vent port 20. <IMAGE>

Description

SPECIFICATION Quick fluid exhaust valve The present invention relates to a quick fluid exhaust valve.

Hydraulic control systems used to control underwater equipment, such as pilot control valves for controlling a blowout preventer, as shown in U.S. Patent No. 4,328,826, require the use of long lengths of control hoses to pilot the subsea control valves. The response time to actuate the control valves is proportionately increased with the increase in the length of the control hose. Pressurising the control hose to the pressure required to operate the valve delays the time required for operating the valve and any safety equipment. Furthermore, the delay time for exhausting pilot pressure back to the point of origin affects the closing time of the valve. The time required to pressurise the control hose is much less than the time required to exhaust the pressure.Valuable time can be saved by exhausing the pilot pressure at the subsea control valves instead of venting pressure back to the surface.

The present invention is directed to an improved quick fluid exhaust valve which can be located adjacent the equipment to be controlled and can quickly vent hydraulic fluid adjacent the control valves without requiring venting back to the pressure source. Preferably, spring means are provided between the housing and the assembly urging the assembly towards the vent valve seat.

The quick fluid exhaust valve of the present invention uses face seals which are make and break seals with controlled seating areas which are less prone to leak and therefore provide positive seating and actuation. An embodiment of the invention will now be described by way of example, reference being made to the accompanying drawings in which:: Figure 1 is an elevational view, in cross section, of a quick fluid exhaust valve according to the present invention in its normal unactuated position, Figure 2 is a fragmentary elevational view, in cross section, of a portion of the valve shown in Figure 1 in the open position to allow fluid flow from the inlet to the outlet port, Figure 3 is a cross-sectional view taken along the line 3-3 of Figure 1, Figure 4 is an elevational view, in cross section, of the valve of Figure 1 shown in the vent position, and Figure 5 is an elevational view, to a reduced scale in cross section, of the quick exhaust valve of the present invention connected to a subsea pilot valve actuator.

Referring to Figure 1, the quick fluid exhaust valve 10 includes a housing 1 2 having a chamber 14, an inlet port 1 6, an outlet or function port 18, and a vent port 20, all in communication with the chamber 14. The inlet port 1 6 is directly connected to the chamber 14, whereas the outlet or function port 1 8 is connected, as shown in Figures 1 and 3, to the chamber 14 by passages 22. The vent port 20 extends into the chamber 14 through passages 24 and opening 26.

A vent valve seat 28 is positioned about the vent port opening 26. An internal valve assembly 30 is sealingly movable in the chamber 14. The assembly 30 includes a vent valve element 32 having a face seal 34 for seating on the seat 28 for closing communication between the vent port 24 and the chamber 14. The face seal 34 provides a make and break seal with controlled seating area which is less prone to leak than conventional O-ring seals. The assembly 30 also includes a passageway 36 therethrough which is in communication at one end with the inlet port 1 6 and at the other end with the chamber 14 for supplying fluid to the outlet port 1 8 through the passages 22. The assembly 30 also includes an outlet valve seat 38 adjacent the outlet end of the passageway 36.An outlet port valve element 40 is seatingly slidable on the exterior of the valve element 32 and includes a face seal 42 for seating on the outlet valve seat 38. The valve element 40 sealingly engages the valve element 32 by an O-ring 41 thereby forming a piston. Spring means 44 yieldably urges the outlet port valve element 40 onto the outlet port valve seat 38 for closing the communication of the passageway 36 and inlet port 1 6 from the outlet port 1 8. That is, the spring means 44 normally urges the port valve element 40 to the closed position but the element 40 opens upon fluid flow through the inlet port 1 6 and passageway 36.

The assembly 30 is exposed on its first side 31 to the fluid pressure in the inlet port 1 6 whereby the inlet port 1 6 pressure acts to move the assembly 30 to seat the vent port valve element 32 on the vent port valve seat 28, thereby closing the communication of the vent port 20 with the chamber 14. In addition, spring 48 is provided between the housing 1 2 and the valve assembly 30 to assist the fluid pressure on the assembly 30 to normally seat the vent valve element 32 on its coacting seat 28.The other end 38 of the assembly is exposed to the pressure at the outlet port 1 8 whereby when the inlet fluid pressure at the inlet port decreases, the pressure at the outlet port 18 will act on the assembly 30 to move the valve element 32 away from the vent valve seat 28 opening communication between the chamber 14 and the vent port 20. In addition, fluid from the outlet port 18 acts on the piston valve element 40 when the inlet pressure at the port 1 6 decreases to close the communication of the passageway 36 with the chamber 1 4 whereby all of the excess pressure at the outlet port 1 8 will vent through the opening 26 to the vent port 20.

In Figure 1 the valve is shown in its normal inoperative position. When it is desired to provide pressure to operate a function, inlet pressure is applied at the inlet port 16 and as best seen in Figure 2 flows through passageway 36, moves the outlet port valve element 40 away from its seat 38 allowing the pressurised fluid to enter the chamber 14, and into passages 22 and flow out of the outlet port 1 8 to perform its function. In this position, as indicated in Figure 2, the vent valve element 32 maintains its seated position against the vent port valve seat 28 thereby blocking communication between the chamber 14 and the vent port 20.

In order to exhaust the fluid quickly from the outlet port 18, the pressure to the inlet port 1 6 is reduced or shut off. As best seen in Figure 4, the now high pressure from the outlet port 1 8 will flow back through the passageways 22 into the chamber 14 and act across the second end or valve seat 38 of the valve assembly 30 overcoming the spring 48 causing the valve element 32 to retract from the vent port valve seat 28. Also, the fluid from the outlet port 18 acts against the piston valve element 40 closing off communication of the passageway 36 and inlet port 1 6 with the chamber 14. Therefore, all of the fluid from the outlet port 18 is vented out the opening 26, passages 24 and the vent port 20.

Preferably, for underwater work, the vent port 20 is covered with a resilient O-ring 50 which allows fluid to be exhausted from the vent port 20 but prevents the admission of environmental fluid such as seawater into the valve housing 12.

Figure 5 illustrates the interconnection of the quick release exhaust valve 10 of the present invention with a conventional pilot operated subsea actuator 52 in which the outlet port 18a of the valve 10 is directly connected to the subsea valve 52 to actuate a pilot piston 54 of a conventional valve actuator 52.

Claims (4)

1. A quick fluid exhaust valve comprising a housing having a chamber and an inlet port, outlet port and vent port in communication with the chamber; a vent valve seat positioned about the vent port; an internal valve assembly sealingly movable in the chamber, said assembly including a vent valve element with a face seal for seating on the vent valve seat for closing communication between the vent port and said chamber; a passageway therethrough in communication between the inlet port and the outlet port for supplying fluid to the outlet port; an outlet valve seat adjacent the passageway; an outlet port valve element slidably positioned on the assembly including a face seal for seating on the outlet valve seat, and spring means normally urging said outlet port valve element onto the outlet port valve seat closing communication of the passageway with the outlet port but opening upon fluid flow through the inlet port and said passageway; said assembly being exposed to the inlet port whereby inlet port pressure acts on the assembly to seat the vent port valve element on the vent port valve seat; said assembly and said outlet valve element being exposed to the pressure at the outlet port whereby when inlet fluid pressure decreases the pressure at the outlet port will act on the assembly and outlet valve element to close the passageway and open the vent port.

2. A valve according to claim 1 including spring means between the housing and the assembly urging said assembly towards said vent valve seat.

3. A valve according to claim 2, wherein said vent port is connected to the inlet of a pilot operated subsea actuator.

4. A quick fluid exhaust valve substantially as hereinbefore described with reference to the accompanying drawings.