WO2015136281A1

WO2015136281A1 - In-line valves

Info

Publication number: WO2015136281A1
Application number: PCT/GB2015/050710
Authority: WO
Inventors: Kurt Canfield
Original assignee: Safety Critical Analysis Limited
Priority date: 2014-03-12
Filing date: 2015-03-11
Publication date: 2015-09-17
Also published as: GB201404336D0; GB2524038A

Abstract

An in-line pipe valve is disclosed comprising:- i) a pipe; ii) a valve means able to fully close off the flow in the pipe, partially open to allow a limited flow or fully open to allow full flow through the means and along the pipe; iii) an operating means able to move the valve means from the fully closed position, through the partially open position(s) to the fully open position and back again; iv) an access cover removable to allow access for maintaining / repairing the valve and operating means and replaceable to enclose the valve and operating means and protect them from external damage and ingress of foreign material; v) a control means connectable to the operating means and able to cause the operating means to move the valve means between its closed, partially open and fully open positions and back again, as required; and vi) a means to connect the control means to the operating means and so make the in-line valve operable; characterised in that the valve means, operating means and access cover all lie within the confines of the circumference of the pipe or are adjacent to the circumference and the access cover is flush with, or faired into, said circumference so that external influences, such as a dragging anchor cable, will pass over the in-line pipe valve and / or its faired access cover without damaging said valve means, operating means or access cover. The design and location of the valve and its cover enable the cover to be removed and the valve, operating means or ancillary equipment located under the cover to be replaced in situ, thus minimising downtime. The faired cover is designed to deflect dragging anchor cables, thus protecting the valve operating means.

Description

IN-LINE VALVES

This specification relates to in-line valves, particularly but not exclusively, where access to the valve is limited and / or where it may be subject to arduous conditions, such as downhole applications or where the pipeline is on, or under, the seabed.

Current designs of in-line valve, such as butterfly valves usually have external elements, like the actuating means and bearings, at the diametrically opposite ends of the operating shaft. As these elements are outside the pipe itself, they are highly vulnerable, e.g. to corrosion from the seawater, abrasion from grit carried by currents, fouling by marine organisms or even being broken off altogether, e.g. by a dragging anchor (Fig. 16). Other types of valve, e.g. gate valves, have even more of their structure projecting away from the pipe and so are potentially even more vulnerable.

Referring to prior art Figs. 1 and 2, a butterfly valve 1 fits inside pipe 8 and consists of a flap 2 mounted on axle 3. When closed, flap 2A rests on lands 6 and 6' and is rotatable by axle 3, e.g. to a partly open position 2B, by actuator 4. As shown, actuator 4 and bearing 5 lie outside the circumference of pipe 8 and are thus vulnerable to damage. Letters A and B show the areas of flap 2 on which the fluid, flowing 7 as shown, in pipe 8 presses. When closed, area A is less than area B due to the presence of land 6' (Fig. 1) so that when closed, valve 1 should remain closed. Unfortunately, this is only true if actuator 4 is permanently activated to maintain valve 1 closed. If this activation fails and flap 2 moves slightly, e.g. due to vibration in the pipeline 8, fluid 7 will squeeze into the gap between upstream land 6' and flap 2; this will effectively make areas A and B equal in size and the load on each half (pressure x area) will be the same. Thus, further vibrations might open the valve further, e.g. 2B.

If actuator 4 was damaged, say by a dragging anchor (Fig. 16), this would almost certainly bend axle 3, requiring a complete replacement of valve 1 , which would involve breaking into pipe 8 - a major operation, usually with considerable downtime and loss of production.

Thus, there is serious need for an in-line valve, for use in operations downhole and / or on / under the seabed, with extreme reliability and resilience to damage, i.e. where it and the operating equipment is protected from damage and easily repairable if any damage, or natural failures, do occur. It is also important that, should damage occur, the valve does not revert to another operating condition, i.e. it always fails in a predetermined safe position. According to the invention, there is provided an in-line pipe valve comprising:- i) a pipe;

ii) a valve means able to fully close off the flow in the pipe, partially open to allow a limited flow or fully open to allow full flow through the means and along the pipe; iii) an operating means able to move the valve means from the fully closed position, through the partially open position(s) to the fully open position and back again; iv) an access cover removable to allow access for maintaining / repairing the valve and operating means and replaceable to enclose the valve and operating means and protect them from external damage and ingress of foreign material; v) a control means connectable to the operating means and able to cause the

operating means to move the valve means between its closed, partially open and fully open positions and back again, as required; and

vi) a means to connect the control means to the operating means and so make the in-line valve operable;

characterised in that the valve means, operating means and access cover all lie within the confines of the circumference of the pipe or are adjacent to the circumference and the access cover is flush with, or faired into, said circumference so that external influences, such as a dragging anchor cable, will pass over the in-line pipe valve and / or its faired access cover without damaging said valve means, operating means or access cover.

According to a first variation of the invention, the pipe is of robust construction and appropriate for use downhole in oil / gas recovery operations, and / or on or under the seabed and / or in other operations where ultrahigh integrity is required.

According to a second variation of the invention, the valve means is a hinged member movable within the flow passage either to close it fully, partially open it or open it fully to allow flow along the pipe.

According to a third variation of the invention, when the valve means is in the fully closed or partly open positions, the pressure of the fluid on the valve does not act to force the valve into an open or further open position.

According to a fourth variation of the invention, the operating means is electrical / electronic in nature.

According to a fifth variation of the invention, the operating means is hydraulic in nature. According to a sixth variation of the invention, the operating means is pneumatic in nature.

According to a seventh variation of the invention, the access cover is removable to permit repair / replacement of the operating means.

According to an eighth variation of the invention, the access cover is removabfe to permit repair / replacement of the valve means.

According to a ninth variation of the invention, the access cover is removable to permit repair / replacement of any ancillary equipment associated with the in-line pipe valve.

According to a tenth variation of the invention, the access cover is adapted for connection of the control means to the operating means of the in-line valve.

According to an eleventh variation of the invention, a guard is provided to protect the point of connection of the control means from externa! damage, e.g. from a dragging anchor cable.

According to a twelfth variation of the invention, monitoring means are provided to indicate the position of the valve.

According to a thirteenth variation of the invention, means are provided to ensure that, in the event of a failure the valve wiil move to, or remain in, a predetermined position, i.e. fail open, fail closed or fail last (fail in its last position).

In a preferred application of the in-line valve of the invention, a section of the bore of the pipe is separated from the flow part and the valve located so that it moves into the flow part to close, or partially close, off the flow and moves into the separated part to open fully, or partially open the flow passage. The operating means is located in the separated part so that it is all, or essentially all, contained within the circumference of the pipe. A removable cover is provided over the separated part so that the cover is either flush with the circumference or forms a small faired bulge on the pipe. The separated part is completely isolated from the flow passage so that no fluid from the flow passage can enter and the cover is provided with sealing to prevent external ingress of foreign material. The design of the cover, whether flush or a faired bulge, allows dragging anchor cables to pass past, or over, without damaging the valve or its operating means. When the cover is removed, access is provided for repair, or replacement, of the valve, its operating means and any ancillary equipment located in the separate part. Repairs or maintenance can thus be effected underwater, without having to break the pipe.

For a clearer understanding of the invention and to show how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which :-

Figure 1 is a sectional end elevation of a butterfly valve in a pipeline (Prior art);

Figure 2 is a sectional, side elevation of the butterfly valve of Figure 1 showing the valve in both closed and partly open positions (Prior art);

Figure 3 is a plan view of a valve according to the invention with the cover removed, shown in the closed position;

Figure 4 is a sectional elevation of the valve shown in Figure 3 along the line AA;

Figure 5 is a side elevation of the valve shown in Figures 3 and 4;

Figure 6 is a sectional end view of the valve in Figure 5 along the line BB;

Figure 7 is a plan view of the valve, shown in Figure 3, with the cover removed, shown in the fully open position;

Figure 8 is a sectional elevation of the valve shown in Figure 7 along the line AA;

Figure 9 is a side elevation of the valve shown in Figures 7 and 8;

Figure 10 is a sectional end view of the valve in Figure 9 along the line BB;

Figure 11 is an exploded sectional side elevation of another valve according to the

invention shown with the cover partly removed;

Figure 12 is an exploded perspective view of the valve shown in Figure 11;

Figure 13 is a plan view of the valve shown in Figure 11 ;

Figure 14 is an exploded side elevation of the valve shown in Figure 11 ;

Figure 15 is a part sectional side elevation of a vaive according to the invention shown in a partly open position;

Figure 16 is a diagrammatic representation of a butterfly valve about to be damaged by a dragging anchor cable )Prior art);

Figure 17 is a diagrammatic representation of an anchor engaging with a pipeline;

Figure 18 is a diagrammatic representation of an anchor dragging along a pipeline; and Figure 19 is a diagrammatic representation of an anchor cable dragging past a valve according to the invention. In the following description, the same reference numeral is used for the same components in different Figures or for different components fulfilling an identical function.

As shown in Figs. 3-10, a hole is cut into pipe 11 and a separate part is formed in the bore of the pipe 11 by angled members 12 and flat member 26. As shown (Fig. 10), the separate part occupies the upper half of the bore of pipe 1 1. Referring to Fig. 3, in-line valve 10 is fitted into pipe 11 with cover 20 (Fig. 11 ) secured in place. In Figs. 3-10, cover 20 (Fig. 11 ) is removed showing operating means 14, 15 consisting of piston rod 14 and operating cylinder 5. Cylinder 15 pivots about bearing 16 in supports 17 Operating means 14 and 15 may be an electrical solenoid system or hydraulic or pneumatic in nature.

As shown, valve member 13 has the shape of a right cylindrical sector, consisting of two parallel faces 13B (Fig. 15) and a circumferential arc 13A. It is located in a closely- toleranced rectangular hole set into plate 26 and is rotatable about bearing 40 by operating means 14 and 15. Faces 13B seal against lands 19 (Figs. 6 and 10) and arc face 13A bears against contact edge 27 of plate 26. As shown, arc face 13A is provided with a sealing membrane 13C, which bears against edge 27 on member 26. A similar sealing membrane (not shown) is provided on each parallel face 13B and seals against respective land 19 (Figs. 6 and 10). Bearing 40 is also provided with sealing so that no fluid 18 flowing in pipe 11 can enter the separate part (operating space) formed by members 12, 26 and cover 20.

When closed (Figs. 11 ), lug 13D (Fig. 15) on valve 13 engages with groove 28 in land 19A and lug 13E contacts member 26 to form a seal to close off the flow 18. When fully open (Fig. 8), lug 13D contacts member 26. Lugs 13D and E limit the movement of operating means 14 and 15, so that valve 13 may be positively moved to the fully open and firmly closed positions.

The separate part (operating space) formed by members 12 and 26 is ciosable by cover 20 (Fig. 11 ), secured by set screws 22 and sealed by a gasket (not shown). This will prevent ingress of water if under the sea and maintain the separate part (operating space) around operating means 14, 15 and above valve 13 dry. Cover 20 adds a minimal additional dimension to the diameter of pipe 11 and is provided with faired ends 21 and sloping sides 21 A (Fig. 14). Angled member 24 is faired away from cover 20 and allows a connection to be made with operating means 14, 15 via gland 23 (Figs. 1 1-14). The connection may be electrical wiring, hydraulic or pneumatic piping 29 (Fig. 19), which would be secured to pipe 11 (not shown). A guard 39 may be provided to protect member 24 and gland 23. Though highly reliable operating means 14 and 15 will be used, failures do occur and it is a feature of the design of the invention that a failed operating means may be replaced in situ, i.e. without having to break pipe 1 , blank off the ends and bring the valve section up to the surface. Techniques have been developed to isolate the problem area from the sea and create a dry environment in which a person or robot can remove cover 20, replace operating means 14, 15 and reassemble the valve 10 into full working order.

The actual valve member 13 is also replaceable as is / are other ancillary equipment(s), e.g. apparatus to monitor the position of valve 13. In addition to apparatus to monitor the position of valve 13, a range of other equipment may be located under cover 20, e.g.

sensors to measure the temperature, pH or flowrate of fluid 8, or vibration in the pipeline, etc.

It is a feature of the invention that, in the event of failure of the operating means, the valve will either remain in its then position (fail last) or move positively to a predetermined safe position, e.g. fully open (fail open) or fully closed (fail closed). One way of doing this is for a spring 25 to become operational upon failure of means 14, 15 by, either opening or closing valve 13, as required.

Pipelines on the seabed tend to be taken for granted and the sailors above tend to forget about them and carry on with their fishing and sailing activities oblivious of what might be on the seabed. Thus, it is common for anchors to be dropped on and catch round pipelines 8 or 1 , e.g. Fig.17. Anchors 30 generally consist of a shaft 31 with a curved member 32 at the bottom and the bit 34 at the top near the connection 35 to cable 36. (Bit 34 is normally at right angles to curved member 32 but is shown thus for illustrative purposes only.) Flukes 33 enable the anchor to dig into the seabed (not shown) and under pipeline 8,11 (Fig. 17). Fig. 16 shows an anchor cable 36 dragging in direction 37, snagging pipeline 8 (Fig. 18) and sliding along it 38. When it reaches butterfly valve 1 , it will catch on actuator 4 and, probably, damage it.

In the case of the invention (Fig. 19), such an anchor cable 36 dragging 38 along pipeline 11 would ride up 38A over fairing 21 and / or sloping sides 21 A, up 38C over guard 39 and along 38D, hopefully, without damaging member 24, gasket 23 or cables 29. Guard 39 would be adapted to provide protection irrespective of the direction 38 in which an anchor cable was dragging. In the event of damage to cable 39 or gland 23, the damage should normally be readily repairable. In the event of gross damage, a replacement cover 20 could be fitted - again a quick and straightforward repair (by oil industry standards). The skilled person will note that the invention places valve 13 and operating means 14 and 15 effectively inside the bore of pipe 1 and out of the area subject to likely undersea damage. Where 'normal' failures or accidental damage do occur, replacements / repairs can be readily effected. This adds at least an order of magnitude to the reliability and availability to the valves 10 and the pipeline 1 1 they serve. The only problems which could not be resolved quickly would be major damage to the pipeline in way of the valve, i.e. effective destruction of that section of the pipeline.

Claims

Claims:

1. An in-line pipe valve comprising:- i) a pipe;

2. An in-line pipe valve, as claimed in claim 1 , wherein the pipe is of robust construction and appropriate for use downhole in oil / gas recovery operations, and / or on or under the seabed and / or in other operations where ultrahigh integrity is required.

3. An in-line pipe valve, as claimed in claim 2, wherein the valve means is a hinged member movable within the flow passage either to close it fully, partially open it or open it fully to allow flow along the pipe.

4. An in-line pipe valve, as claimed in claim 3, wherein, when the valve means is in the fully closed or partly open positions, the pressure of the fluid on the valve does not act to force the valve into an open or further open position.

5. An in-line pipe valve, as claimed in any preceding claim, wherein the operating means is electrical / electronic in nature.

6. An in-line pipe valve, as claimed in claims 1-4, wherein the operating means is hydraulic in nature.

7. An in-line pipe valve, as claimed in claims 1-4, wherein the operating means is pneumatic in nature.

8. An in-line pipe valve, as claimed in any preceding claim, wherein the access cover is removable to permit repair / replacement of the operating means.

9. An in-line pipe valve, as claimed in claims 1-8, wherein the access cover is removable to permit repair / replacement of the valve means.

10. An in-line pipe valve, as claimed in claims 1-8, wherein the access cover is removable to permit repair / replacement of any ancillary equipment associated with the in- line pipe valve.

1 . An in-line pipe valve, as claimed in claims 8-10, wherein the access cover is adapted for connection of the control means to the operating means of the in-line valve.

12. An in-line pipe valve, as claimed in claim 11 , wherein a guard is provided to protect the point of connection of the control means from external damage, e.g. from a dragging anchor cable.

13. An in-line pipe valve, as claimed in any preceding claim, wherein monitoring means are provided to indicate the position of the valve.

14. An in-line pipe valve, as claimed in any preceding claim, wherein means are provided to ensure that, in the event of a -ailure the valve will move to, or remain in, a predetermined position, i.e. fail open, fail closed or fail last (fail in its last position).

15 An in-line pipe valve, as describee in and by the above statement with reference to the accompanying Figures 3-15 and 17-19.