NO341017B1

NO341017B1 - High pressure gas valve

Info

Publication number: NO341017B1
Application number: NO20160814A
Authority: NO
Inventors: Tord Martinsen
Original assignee: Safelink As
Priority date: 2016-05-12
Filing date: 2016-05-12
Publication date: 2017-08-07
Also published as: NO20160814A1

Description

The high pressure gas valve (HPGV) is a gas tight cartridge valve. It allows sealing of high pressure gas with hydraulic fluid under much lower pressure, due to the area difference between the upper and lower part of the piston. Another embodiment of the valve is used as a normally closed gas tight check valve.

BACKGROUND OF THE INVENTION

Prior art cartridge valves are usually only able to seal for hydraulic oil, not gas, as shown in figure 3. No currently available valves allowthe userto close the valve with low pressure hydraulic oil. There is a need for this kind of valve in e.g. heave compensation equipment, where the gas pressure can be at 500 bar or more and the control hydraulics operate at maximum 350 bar, and usually lower pressure. There is also a lack of cartridge based gas tight check valves, another embodiment of the invention solves that issue.

US 2015/0316170 describes a subsurface safety valve håving multiple pistens used to increase the opening force. One safety valve includes a housing håving a piston bore defined therein, and configured to receive hydraulic fluid pressure, the piston bore providing an upper bore håving a first diameter and a lower bore håving a second diameter smaller than the first diameter. A piston assembly is movably arranged within the piston bore and comprising an upper piston arranged in and configured to sealingly engage the lower bore, and a connection rod coupling the upper and lower pistens, wherein the cavity is defined between the upper and the lower pistens within the piston bore and the piston rod extends within the cavity.

US 4,257,442 describes a choke for controlling the flow of drilling mud which is highly abrasive. The abrasive drilling mud is introduced through a lateral port, a fluid actuated double acting piston is forced to e choke control position. The piston has appended a sleeve of wear resultant material.

SUMMARY OF THE INVENTION

The main features of the present invention are given in the independent claim. Additional features of the invention are given in the dependent claims.

The novel design of the HPGV allows gas tight sealing between two ports on the valve, under high pressure, using significantly lower oil pressure to close and open the valve.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1 is a schematic illustration of the HPGV according to the present invention in which the major component parts of the valve are specifically idenfrfied. Figures 2 is a schematic illustration of another embodiment of the HPGV according to the present invention in which the major component parts of the valve are specifically identified.

Figure 3 is an illustration of a prior art cartridge valve.

DETAILED DESCRIPTION

As previously mentioned, figure 1 illustrates the first embodiment of the high pressure gas valve (HPGV (0)) with all of the major sub-components numbered 1 through 8. In Table 1 below, the component description is identified. The HPGV (0) can be used with hydraulic fluids and gases. One application can be in heave compensators that often contain high pressure gas volumes that needs to be separated from iow pressure gas. Valve actuation is usually done with hydraulics that operate at a lower pressure than the high pressure gas, which makes it hard to operate. The HPGV (0) can be actuated by Iow pressure hydraulic fluid because of the area difference between the two pressure sides. How much lower is given by the square of the ratio of diameter C to diameter D. As mentioned this valve (0) is a cartridge design which means that a cavity is made in a hydraulic block and the valve is inserted. A first hydraulic line is connected to port C, which is the pilot pressure, a second hydraulic line is connected to port B and is separated from a third hydraulic line, connected to port A, when the piston (2) is in the closed position and the first axial gas seal (5) is pushed against the seal housing (1). Port A, B and C can be connected to either gas or oil under high pressure. The minimum one first dynamic seal (6) and minimum one second dynamic seal ensures that no fluid or gas enters the small volume between the first dynamic seal (6) and the second dynamic seal (8). A first and second static seal is used to separate the three ports; A, B and C. The square of the diameter of A should be close to N times the square of the diameter of B to not create a flow restrictbn.

Figure 2 illustrates the second embodiment (10) of the valve with all of the major sub-components numbered 11 through 19. In Table 1 below, the component description is identified. The second embodiment (10) is a gas tight cartridge check valve that is normally closed. Pilot pressure is applied to port A. A spring or a small gas volume is connected to port D and will close the valve rf the pilot pressure is lost.

Flow direction can be from port B to C or opposite. The valve (10) consists of a valve housing (11) that has minimum three static seals (14,15,16) on the outer diameter, with three different diameters, that effectively separate port A, B, C, and D. Further the valve consists of two piston parts (12,13), where piston (12) is fastened to piston (13) using a threaded connection. The pistens have minimum two dynamic seals (17,

19) that effectively seals gas coming from port B and C from entering port A or D. An axial seal (18) seals between port B and C if the pilot pressure on port A is lost. The square of the diameter of B times N should be close to M times the square of the diameter of C to not create a flow restriction.

Claims

1. High pressure gas valve (0) comprising: a valve housing (1), suitable for mounting inside a hydraulic block, with two different inside and outside diameters, with minimum one first static seal (4) installed at the largest outside diameter and minimum one second static seal (8) installed at the smallest outside diameter; a piston (2), installed inside the valve housing (1), with two different dynamic seal diameters; a seal locking means (3), fastened to the piston (2); an axial gas seal (5), mounted between the piston (2) and seal locking means (3); a first dynamic seal (6), installed on the piston (2), at the smallest diameter; and a second dynamic seal (7), installed on the piston (2), at the largest diameter.

2. High pressure gas valve (0) according to claim 1, where a gas tight seal is achieved when the piston (2) is pushed against the right side of the housing (1), effectively blocking port A from port B.

3. High pressure gas valve (10) in check valve embodiment comprising: a valve housing (11), suitable for mounting inside a hydraulic block, with three different outside diameters and two different inside diameters, with minimum one first static seal (16) installed at the largest outside diameter, minimum one first static seal (15) installed at the middle outside diameter and minimum one third static seal (14) installed at the smallest outside diameter; a first piston (12), installed inside the valve housing (11), and fastened to the second piston (13); an axial gas seal (18), mounted between the first piston (12) and the second piston (13); a first dynamic seal (17), installed on the second piston (13); and a second dynamic seal (19), installed on the first piston (12);

4. High pressure gas valve (10) in check valve embodiment according to claim 1, where a gas tight seal is achieved when the second piston (13) is pushed against the left side of the housing (11), effectively blocking port B from port C.