WO2007051254A1

WO2007051254A1 - Pressure release valve, system and method of use

Info

Publication number: WO2007051254A1
Application number: PCT/AU2006/001647
Authority: WO
Inventors: Mark Andrew Fogarty
Original assignee: Mark Andrew Fogarty
Priority date: 2005-11-04
Filing date: 2006-11-06
Publication date: 2007-05-10
Also published as: AU2006308808A1; AU2006308808B2

Abstract

An interlocking isolation valve assembly is described. The valve assembly is adapted to be connected to a hydraulic circuit, and it includes: a first isolation valve and a second isolation valve and an interlock means wherein the second valve is inhibited from moving to a return position if the first valve is at least partially in an open position, and the first valve is inhibited from moving to the open position if the second valve is in the return position. There is also described a method for venting a high pressure hydraulic machine such as for example a longwall roof support, in which the high pressure circuit is vented to the return circuit. Another aspect of the invention is a high pressure hydraulic machine which in one form is a longwall roof support, which is removed from a closed loop circuit by venting a high pressure circuit to a return circuit.

Description

PRESSURE RELEASE VALVE, SYSTEM AND METHOD OF USE

Field of the Invention

The present invention relates generally to a valve apparatus and system suitable for use in high pressure hydraulic fluid applications and/or circuits, and is particularly useful when releasing the high pressure fluid in and/or from the circuit. Particular applications for the valve and system described herein include removing, installing and isolating devices such as for example, longwall roof supports, high pressure hydraulic accumulators and all machines which run a closed loop system with a pressure and return circuit. Therefore, the valve, method and system described herein have application in many other circuits which utilise high pressure hydraulics, particularly closed loop systems. It will be convenient to hereinafter describe the valve and system and circuit of the present invention with reference to the particular application of longwall roof supports, but it is to be understood that this is not intended to be a limitation of the present invention.

Background to the Invention

It is common practice in many high pressure hydraulic applications to vent certain amounts of high pressure fluid to atmosphere. This practice is fraught with danger, not least of which is the high risk of potentially fatal high pressure fluid injection.

Sometimes, a diffuser is installed to alleviate the risk of high pressure fluid injection, however, even with the diffuser installed, there is still a risk of fluid injection due to the extremely high pressures associated with these circuits, which commonly extend to 350 Bar.

Using a diffuser still does not alleviate noise and chemical pollution introduced to the work and natural environment. The present invention seeks to ameliorate one or more of the abovementioned disadvantages.

Summary of the Invention

According to one aspect of the present invention there is provided an interlocking isolation valve assembly adapted to be connected at a selected point in a hydraulic circuit so as to define a working side and a supply side of the interlocking isolation valve assembly, which includes: a first isolation valve for isolating a first fluid gallery, the first isolation valve movable between an open position in which fluid may flow in the first fluid gallery and a return position in which fluid from the supply side is inhibited from flowing to the working side of the first fluid gallery; a second isolation valve for isolating a second fluid gallery, the second fluid gallery connecting the first fluid gallery and a return gallery of the hydraulic circuit, the second isolation valve movable between a return position in which fluid flows in the second fluid gallery and a closed position in which fluid does not flow in the second fluid gallery; and an interlock means wherein the second valve is inhibited from moving to the return position if the first valve is at least partially in the open position, and the first valve is inhibited from moving to the open position if the second valve is in the return position.

Preferably, the interlocking means is in the form of a gate or barrier associated with a handle or valve axle of each respective valve, wherein a first gate or barrier is substantially disposed in a return path of a second gate or barrier when the first valve is at least partially in the open position, and the second gate substantially occupies an opening path of the first gate when the second valve is at least partially in the return position.

Preferably the at least one gate is in the form of an arcuate handle extension, or arcuate attachment to a valve axle.

Preferably each gate is a sector shape, a centre region of the sector shape being disposed concentric to the handle pivot axis. Preferably, a radial edge wall of one sector is substantially collinear with a tangent of an arcuate wall of the other sector so that the sectors substantially abut with little or no backlash when one sector is in a blocking position.

Preferably a check valve is provided in the third gallery adjacent the upstream port, to inhibit flow of working fluid through the upstream port.

Preferably a pressure gauge is provided in order to demonstrate the pressure in the first gallery to a user.

Preferably a locking means is provided in order to lock the first isolation valve in a closed position.

According to another aspect of the present invention there is provided a high pressure hydraulic apparatus, the apparatus including: a high pressure hydraulic machine; a hydraulic circuit for operating the high pressure hydraulic machine and which includes a high or working pressure gallery or line and a return or low pressure gallery or line, and further including a valve apparatus for disconnecting and/or installing the hydraulic machine from the hydraulic circuit, the valve apparatus being connected to the circuit so that the hydraulic machine is connected to a working side of the valve and a hydraulic supply is connected to a supply side of the valve; the valve apparatus being configured to control flow and pressure in the high pressure gallery and to control flow and pressure from the high pressure gallery or line to the return line; the valve including an interlock wherein the working side of the high pressure line may be vented to the return line.

Preferably the hydraulic machine is a longwall roof support.

According to yet another aspect of the present invention there is provided a method for venting a high pressure hydraulic machine on a working side of a selected point in an operating hydraulic circuit, the hydraulic circuit having a high pressure gallery or lines and a return pressure gallery or lines, the method including the steps of: isolating a supply side of the high pressure gallery or line at the selected point in the hydraulic circuit; connecting a working side of the selected point of the high pressure gallery or line to the return line at the selected point so that working pressure in the working side of the high pressure hydraulic machine is vented to the return line.

Preferably the connection is effected by means of opening a valve.

Preferably the selected point is proximal the hydraulic machine so that peak pressure is transitory to reduce risk of blowing return lines.

Preferably the high pressure hydraulic machine is a longwall roof support.

Preferably the step of isolating the supply side involves operating an interlocked valve assembly, so that a first valve is operated to close the high pressure gallery at the supply side and a second valve is then operated to connect the working side of the high pressure gallery to the return gallery, wherein the interlocked valve assembly inhibits the return operation until the closing operation has been fully completed.

Brief Description of the Drawings

In order to enable a clearer understanding, the invention will hereinafter be described with reference to drawings and description of preferred embodiments. In the drawings:

Fig. 1 is an isometric view of an interlocking isolation valve assembly in accordance with a preferred embodiment of the present invention, the valve assembly shown in a venting position in which trapped work side pressure returns to a return circuit;

Fig. 2 is a schematic diagram of the interlocking isolation valve assembly shown in

Figure 1 showing a circuit diagram of associated galleries, wherein two valves are shown which are both in a closed position; and Fig. 3 is a schematic diagram of a row of longwall roof supports showing connecting points at which to connect the interlocking isolation valve relative to the longwall roof support.

Description of the Preferred Embodiments

Referring to Fig. 1 there is shown an interlocking isolation valve apparatus generally indicated at 10. The valve apparatus 10 includes a first valve 12 in the form of a high pressure valve 14 and a second valve 16 in the form of a low pressure Or return pressure valve 18.

The valve apparatus 10 includes a manifold block 20 which includes galleries 22, including high pressure or working pressure gallery 24 and return galleries 26, the latter of which generally contain lower pressure than those experienced in the working pressure galleries 24. A cross gallery 28 is provided to enable fluid communication between the high pressure gallery 24 and the return pressure gallery 26.

The manifold block 20 is generally connected to a hydraulic circuit 30 in a position relatively proximal a hydraulic machine 99 (Figure 3) in this case being a longwall roof support 98 (Figure 3). An end of the manifold block 20 proximal the hydraulic machine is known as the working side 31 of the block 20 and an end of the manifold block 20 proximal a hydraulic pressure supply, or distal the hydraulic machine is termed the supply side 32 of the block 20.

In normal operation, when the roof support is supporting the longwall roof, the flow and pressure in the valve is as shown by the arrows in Figure 2 (first valve 12 would be open, contrary to the orientation of the handle shown). That is, fluid and pressure in the high pressure gallery normally flows in the direction shown by arrows 34 and fluid and pressure in the return gallery normally flows in the direction shown by arrows 35. First or high pressure valve 12 is disposed upstream of cross port 27 leading to cross gallery 28 and second or low pressure valve 14 is disposed intermediate the cross gallery 28, downstream of cross port 27.

First valve 12 is adapted to move between a closed or return position (shown in Figs 1 and 2) and an open position wherein handle 42 extends parallel to the high pressure gallery 24 (not shown). The first valve 12, in the closed or return position, inhibits flow in the high pressure gallery 24 from the supply side 32, whereas, in the open position (shown in Figure 1), allows flow in the high pressure gallery 24 from the supply side 32 to the working side 31. The second valve 16, in the closed position shown in Figure 2, inhibits flow in the cross gallery 28. In the open position shown in Figure 1, the second valve 16 allows flow from gallery 24 to gallery 26, from working side 31 to supply side 32.

Gates 40 are provided, attached to respective valves 12 and 16. The gates 40 are in the form of extensions 41 of handles 42. The extensions 41 are in the form of sectors 44 and 45 which have radial walls 46, 47, 48 and 49 substantially extending from valve rotation axis 50 and 51, and normal thereto. The sectors 45 have an included angle of approximately π/4 radians or 90° between radial walls. Ends of radial walls are joined by circumferential walls 52 and 53. The two valve axles 50 an d 51 are spaced along high and low pressure galleries, and normal thereto, along the cross gallery, by a distance of approximately the length of the radial walls 46 - 49 so as to reduce backlash in operation.

A check valve 55 is provided in the low pressure or return gallery, so as to inhibit flow against the direction of the arrows.

A pressure gauge (not shown) is provided at approximately the cross port 27 so as to assist in determining whether it is safe to disconnect the high pressure hydraulic machine.

A row of hydraulic roof supports 99 is shown in Figure 3. The valve .10 is shown connected to high and low pressure lines 62 and 64, and proximally positioned to the roof support, which is to say that it is spaced from the high pressure hydraulic roof support 98 by a distance of two supports, for increased safety in case the roof collapses when the roof support is disengaged from the supply pressure. A diffuser is shown at 70.

A lock 80 is shown in order to lock the first high pressure valve 12 in a return position so that the supply side 31 port of the high pressure gallery 24 is not directly opened to the working side 31 once the hydraulic machine 99 is removed. A further isolation valve upstream of the manifold 10 should be used to isolate the manifold 10. Provision 82 is made to receive a tag or padlock in the lock 80.

The valve assembly 10 may be utilised permanently or, more typically, in disconnection use would be connected to each high pressure hydraulic machine in turn in order to disconnect each machine 99 or roof support in a line, starting at the end 85. That is, the manifold 10 would be connected in series between the penultimate support interconnection 90 and the last interconnection 92. Once each machine 99 has been disconnected by the process as described below, the manifold is disconnected and connected to the next roof support 98 in the line so as to disconnect it.

The valves 12 and 16 are ball isolation valves. Valve 12, when even partially in the open position, inhibits the movement of valve 16 to the return position, by virtue of the sector 44 occupying space in the opening path of the sector 45. Similarly, valve 16, when even partially in the return position, inhibits opening of the valve 12, because of the sector 45 and its wall 53 substantially (or slightly loosely) abutting radial wall 46 as soon as it moves even partially into the return position.

Example - operation in disconnection use.

The valve assembly 10 is placed in series in the closed-loop hydraulic circuit 97. Both valves 12 and 16 are closed (as shown in Figure 2). Supply side and return pressure is fed to the valve 10 by opening the first valve 12 (not shown). Then, supply side pressure in the main gallery 24 is closed off by closing valve 12. It is not until the valve 12 has fully closed that the valve 14 will be able to move to the open position for disconnection of machine 99. When the valve 12 is finally closed, the circumferential wall 52 and radial wall 46 of first gate 44 moves out of the closing path of sector 45, and the second valve 14 may then open. Flow and pressure then is allowed to move from working side 32 in high pressure gallery 24 through the cross gallery 28 and into return gallery 26. The check valve 55 inhibits flow back into the machine 99.

In the system shown in Figure 3, each roof support 98 is attached to the high and low pressure in a parallel circuit, by an interconnector block 90. This block 90 can isolate the flow into each roof support 98, which makes it a convenient location to attach the manifold 10.

The manifold 10 in operation allows pressure from the working side 31 of the high pressure gallery 24 to the supply side 32 of the return gallery 26.

The advantage of venting to the return gallery is that there is very little risk of high pressure fluid injection, which is potentially fatal. The valve 10 is placed a relatively short distance from the support 98 being disconnected so that the pressure spike is relatively low, reducing the likelihood of line blowout and any subsequent high pressure fluid injection.

There may be some small residual pressure (up to 4 Bar) in the return lines 26 but this can be easily disconnected without the risk of high pressure fluid injection, even though there may be some small spillage of oil when disconnecting the manifold 10.

Finally, it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements of parts without departing from the spirit or ambit of the invention.

Claims

CLAIMS:

1. An interlocking isolation valve assembly adapted to be connected at a selected point in a hydraulic circuit so as to define a working side and a supply side of the circuit relative to the interlocking isolation valve assembly, which includes: a first isolation valve for isolating a first fluid gallery, the first isolation valve movable between an open position in which fluid may flow in the first fluid gallery and a return position in which fluid from the supply side is inhibited from flowing to the working side of the first fluid gallery; a second isolation valve for isolating a second fluid gallery, the second fluid gallery connecting the first fluid gallery and a return gallery of the hydraulic circuit, the second isolation valve movable between a return position in which fluid flows in the second fluid gallery and a closed position in which fluid does not flow in the second fluid gallery; and an interlock means wherein the second valve is inhibited from moving to the return position if the first valve is at least partially in the open position, and the first valve is inhibited from moving to the open position if the second valve is in the return position.

2. The interlocking isolation valve assembly according to claim 1 wherein the interlocking means is in the form of a gate or barrier associated with a handle or valve axle of each respective valve, wherein a first gate or barrier is substantially disposed in a return path of a second gate or barrier when the first valve is at least partially in the open position, and the second gate substantially occupies an opening path of the first gate when the second valve is at least partially in the return position.

3. The interlocking isolation valve assembly according to claim 2 wherein the at least one gate is in the form of an arcuate handle extension, or arcuate attachment to a valve axle. , ^■

4. The interlocking isolation valve assembly according claim 2 or 3 wherein each gate is a sector shape, a centre region of the sector shape being disposed concentric to the handle pivot axis.

5. The interlocking isolation valve assembly according to clam 4 wherein a radial, edge wall of one sector is substantially collinear with a tangent of an arcuate wall of the other sector so that the sectors substantially abut with little or no backlash when one sector is in a blocking position.

6. The interlocking isolation valve assembly according to any previous claim wherein a check valve is provided in the third gallery adjacent the upstream port, to inhibit flow of working fluid through the upstream port.

7. The interlocking isolation valve assembly according any previous claim wherein a pressure gauge is provided in order to demonstrate the pressure in the first gallery to a user.

8. The interlocking isolation valve assembly according to any previous claim wherein a locking means is provided in order to lock the first isolation valve in a closed position.

9. A high pressure hydraulic apparatus, the apparatus including: a high pressure hydraulic machine; a hydraulic circuit for operating the high pressure hydraulic machine and which includes a high or working pressure gallery or line and a return or low pressure gallery or line, and further including a valve apparatus for disconnecting and/or installing the hydraulic machine from the hydraulic circuit, the valve apparatus being connected to the circuit so that the hydraulic machine is connected to a working side of the valve and a hydraulic supply is connected to a supply side of the valve; the valve apparatus being configured to control flow and pressure in the high pressure gallery and to control flow and pressure from the high pressure gallery or line to the return line; the valve including an interlock wherein the working side of the high pressure line may be vented to the return line.

10. A high pressure hydraulic apparatus in accordance with claim 9 wherein the hydraulic machine is a longwall roof support.

11. A method for venting a high pressure hydraulic machine on a working side of a selected point in an operating hydraulic circuit, the hydraulic circuit having a high pressure gallery or lines and a return pressure gallery or lines, the method including the steps of: isolating a supply side of the high pressure gallery or line at the selected point in the hydraulic circuit; connecting a working side of the selected point of the high pressure gallery or line to the return line at the selected point so that working pressure in the working side of the high pressure hydraulic machine is vented to the return line.

12. The method of claim 11 wherein the connection is by means of opening a valve.

13. The method of claim 11 or 12 wherein the selected point is proximal the hydraulic machine so that peak pressure is transitory to reduce risk of blowing return lines.

14. The method of any one of claims 1 1 - 13 wherein the high pressure hydraulic machine is a longwall roof support.

15. The method of any one of claims 11 - 14 wherein the step of isolating the supply side involves operating an interlocked valve assembly, so that a first valve is operated to close the high pressure gallery at the supply side and a second valve is then operated to connect the working side of the high pressure gallery to the return gallery, wherein the interlocked valve assembly inhibits the return operation until the closing operation has been fully completed.

16. An interlocking isolation valve assembly substantially as hereinbefore described with reference to the attached drawings.

17. A method of venting a hydraulic machine in accordance with the hereinbefore described examples.

18. A high pressure hydraulic machine substantially as hereinbefore described with reference to the attached drawings.

Dated this 6^th day of November, 2006 MARK ANDREW FOGARTY by his Patent Attorneys DAVIES COLLISON CAVE