GB2537134A

GB2537134A - Valve closure device

Info

Publication number: GB2537134A
Application number: GB1505924.9A
Authority: GB
Inventors: Chisholm Martin
Original assignee: Schenck Process Ltd
Current assignee: Schenck Process UK Ltd
Priority date: 2015-04-08
Filing date: 2015-04-08
Publication date: 2016-10-12
Anticipated expiration: 2035-04-08
Also published as: WO2016162677A1; GB201505924D0; GB2537134B

Abstract

A valve has a closure member 118, which may be domed, and one or more shafts, each connected to a pivot 116 which is surrounded by two eccentric bushes 114, 112. The bushes 114, 112 counter rotate to provide linear up and down motion, via the shaft, to the closure member 118. In the figure shown, the closure member 118, is somewhat distanced from a sealing ring. The fully closed position is shown in fig.5, and the fully open position is shown in fig.9. The arrangement may replace an earlier dome valve arrangement with an inflatable seal, and may permit the valve to work at higher temperatures and pressures.

Description

VALVE CLOSURE DEVICE

FIELD OF THE INVENTION

The present invention relates to a valve closure device. More particularly, the present invention relates to a valve closure device capable of opening and closing a valve for pneumatic conveying systems or similar bulk solid handling processes.

BACKGROUND OF THE INVENTION

The conventional Dome Valve (Trade Mark) was invented in 1974 by Brian Snowdon. It consists of a dome shaped closure mounted on two half shafts that enable the dome shape closure to move through 90 degrees between the 'closed' and 'opened' positions. When the valve is in the 'closed' position a moulded rubber seal is inflated using compressed gas so that the seal presses against the dome to form a gas tight seal. Prior to opening the valve the seal is deflated so that it retracts away from the dome allowing the dome to move freely without friction and the associated wear of the seal.

The Dome Valve (Trade Mark) has become an industry standard and is frequently used as part of pneumatic conveying systems and similar applications where a valve is required to shut off a flow of bulk material solids and provide a pressure tight 20 seal.

The conventional Dome Valve (Trade Mark) has been successfully used at pressures of up to 15 barg but the potential for the seal to extrude has prohibited its use at higher pressures. Furthermore, the possible sudden loss of sealing gas pressure and the consequent loss of containment make it unsuitable for high-pressure applications.

The conventional Dome Valve (Trade Mark) is well proven but the limitations are summarised as follows: 1). The maximum operating pressure is 20 barg. Above this pressure the inflating seal can extrude and fail.

2). The maximum practical operating temperature of the valve is around 450 °C. Operating the valve at higher temperatures results in a short seal life of typically 2 months.

3). The potential for a sudden loss of sealing gas pressure make it unsuitable for high-pressure applications where loss of containment would pose a significant hazard, for example, where a sealing failure would result in the release to the surroundings of an inflammable, explosive or toxic gas.

4). The inflating seal can fail rapidly and unexpectedly when used at high-pressure since a small leak across the sealing face will quickly enlarge due to abrasive wear by high-velocity dust or the effects of temperature.

It is an object of at least one aspect of the present invention to obviate or mitigate at least one or more of the aforementioned problems.

It is a further object of the present invention to provide an improved valve sealing device for pneumatic conveying systems capable of controlling the flow of bulk material solids.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a valve closure device comprising: a closure member connected to a first end of at least one substantially vertically oriented shaft; a second end of the at least one substantially vertically oriented shaft located within a first eccentric bush; a second eccentric bush located around the first eccentric bush; wherein on counter-rotating the first and second eccentric bushes the closure member is capable of moving up and down.

Generally speaking, the present invention resides in a valve closure device where a closure member is capable of being moved up and down to form a seal.

The closure member may be any suitable shape that is capable of forming a tight seal and being opened and closed.

The closure member may be dome shaped i.e. convex shaped.

There may be any suitable number of substantially vertically oriented shafts connected to the closure member such as two.

The first eccentric bush may therefore form an inner bush with the second bush forming an outer bush with the first eccentric bush being wholly located within the second bush.

Typically, the first and second bushes may have the same degree of eccentricity. In embodiments where there are two substantially vertically oriented shafts then there will be a pair of first and second eccentric bushes. A second end of each of the substantially vertically oriented shafts may be connect to the respective first eccentric bush which act as an inner bush with the second bushes located around the first bushes in the form of an outer bush. The first end of the substantially vertically oriented shafts may be connected to the closure member.

Around the perimeter of the closure member there may be a sealing ring which is capable of forming a tight effective seal against the closure member. The sealing ring may be annular in shape.

The sealing ring may therefore extend all the way around the upper part of the periphery of the closure member.

The sealing ring may be made from any suitable material such as ceramic and lapped hard metal faced, fully supported 0-rings or quad rings in a metal housing.

The closure member may be moved from an open to a dosed position. Preferably, this operation is performed with no or minimal friction and wear.

To form an effective seal it is preferred that the movement of the closure member is in a straight line at right angles or substantially at right angles to the plane of the sealing ring. This ensures that the gap is dosed equally and that the sealing force between the dome shaped closure and sealing ring is uniformly applied around the circumference of the seal.

The closure member may be moved to an upper position where the closure member forms a tight seal with the sealing ring.

The closure member may be opened by counter-rotating the first and second bushes which has the effect of lowering the closure member. The closure member during this action may therefore be moved away from the seal which has the effect of opening the valve and allowing material to enter.

During the counter-rotation of the first and second bushes this has the effect of moving the least one or more substantially vertically oriented shaft substantially up or down and hence opening or dosing the valve.

In a fully extended up positon, the closure member forms a tight seal against the sealing ring. In the fully lowered positon, the closure member is fully open and maximises the open gap between closure member and the sealing ring.

In use, the first and second (i.e. inner and outer) bushes may be rotated at equal speed in opposite directions. The lateral movement of the inner bush may be offset by the equal and opposite lateral movement of the outer bush.

The movement of each pair of eccentric bushes may be synchronised by gearing to ensure that they counter-rotate at the same speed.

An external lay-shaft may ensure that the movement of the bushes on each side of the valve are synchronised.

A water-cooling system may also be incorporated into the valve closure device. This may allow the valve closure device to be used in high-temperature applications up to 800 degrees C. The valve closure device may be incorporated into a pneumatic conveying system or similar bulk solid handling processes where a valve is required to operate at high pressure and/or high temperature.

The valve closure device may therefore be used as part of a pneumatic conveying system to provide effective cut-off and sealing at high pressure and/or temperature.

The valve closure device may provide material shut-off and sealing of valves to be used in a variety of applications. Typical examples are part of the fuel/sorbent feed to high-pressure gasifier and ash discharge valve from a high-pressure gasifier.

According to a second aspect of the present invention there is provided a pneumatic conveying apparatus or bulk solid handling apparatus comprising a valve closure device, said valve closure device comprising: a closure member connected to a first end of at least one substantially vertically oriented shaft; a second end of the at least one substantially vertically oriented shaft located within a first eccentric bush; a second eccentric bush located around the first eccentric bush; wherein on counter-rotating the first and second eccentric bushes the closure member is capable of moving up and down.

The valve closure device may be as defined in the first aspect.

According to a third aspect of the present invention there is provided a method of opening and closing a valve in a valve closure device comprising: providing a closure member connected to a first end of at least one substantially vertically oriented shaft; providing a second end of the at least one substantially vertically oriented shaft located within a first eccentric bush; providing a second eccentric bush located around the first eccentric bush; wherein on counter-rotating the first and second eccentric bushes the closure member is capable of moving up and down.

The valve closure device may be as defined in the first aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a sectional view of a prior art valve closure device in a closed position; Figure 2 is an expanded view of part of the valve closure device shown in Figure 1; Figure 3 is a sectional of the valve closure device shown in Figures 1 and 2 in an open position; Figure 4 is an expanded view of pad of the valve closure device shown in Figure 3; and Figures 5 to 10 represent the operation of a valve closure device according to an embodiment of the present invention where inner and outer bushes are rotating in opposite direction to provide upwards and downwards movement of a dome shaped closure.

BRIEF DESCRIPTION

Generally speaking, the present invention resides in the provision of a valve closure device capable of opening and closing a valve for pneumatic conveying systems or similar bulk solid handling processes where a valve is required to operate at high pressure and/or high temperature Figure 1 is a sectional view of a prior art valve closure device generally designated 10. The valve closure device 10 is what is known in the field as a Dome Valve (Trade Mark). The valve closure device 10 as shown in Figure 1 has a dome shaped (i.e. convex shaped) closure 12 which is mounted on two half-shafts that enables the dome shaped closure 12 to rotate about pivot points 16.

Figure 1 shows the valve closure device 10 in the closed position where the domed shaped closure 12 is pointing upwards and tightly sealed against inflatable moulded seals 14.

Figure 2 shows that the inflatable moulded seals 14 are capable of being inflated by air being injected through a seal inlet which has the effect of inflating the seal 14 against the dome shaped closure 12. This forms a tight seal.

In Figures 3 and 4, the seal 4 has been deflated and the dome shaped closure rotated through 90 degrees to form an open position. This allows the dome shaped closure 12 to be moved away freely without friction and the associated wear of the seal 14.

Figures 5 to 10 represent an improved valve closure device 100 according to the present invention.

The improved valve closure device 100 overcomes the limitations of the valve closure device 10 shown in Figures 1 to 4. The improved valve closure device maintains the essential features of the original valve closure device and allows a dome shaped closure 110 and a sealing ring 118 to be brought into intimate contact when the domed shaped closure 110 is closed so that they form an effective seal. Prior to opening the valve closure device 100, the dome shaped closure 110 and sealing ring 118 are moved apart to create a clearance so that the dome shaped closure 110 can move between the closed and opened positions without friction and wear.

In Figure 5 there is a cross-section of the improved valve closure device 100 which uses a new method for moving the dome shaped closure 110. To form an effective seal it is important that the movement of the dome shaped closure 110 is in a straight line at right angles to the plane of a sealing ring 118. This ensures that the gap is closed equally and that the sealing force between the dome shaped closure 110 and sealing ring 118 is uniformly applied around the circumference of the seal 118.

Figure 5 shows the dome shaped closure 110 in the most upwards position and tight against the sealing ring 118. The sealing ring 118 extends all the way around the upper part of the periphery of the dome shaped closure 110. The linear movement of the dome shaped closure 100 in an upwards direction is created by using two counter-rotating eccentric bushes 112, 114 as shown in Figures 5 to 8. There is an inner bush 114 and an outer bush 112. Both the inner and outer bushes 112, 114 have the same degree of eccentricity.

In Figure 5 the inner and outer bushes 112, 114 can be seen to be pointing downwards. In this position the dome shaped closure 110 is in its fully extended position with the dome shaped closure tight against the sealing ring 118.

In use, the inner and outer bushes 112, 114 bushes are rotated at equal speed in opposite directions. The lateral movement of the inner bush 114 is offset by the equal and opposite lateral movement of the outer bush 112. For this reason the shafts onto which the dome shaped closure 110 move in a vertical or substantially vertically direction at right angles to the plane of the sealing ring 118.

The movement of each pair of eccentric bushes 112, 114 is synchronised by gearing to ensure that they counter rotate at the same speed. An external lay-shaft ensures that the movement of the bushes 112, 114 on each side of the valve are synchronised.

Obtaining the linear movement required using rotating elements in this way simplifies the pressure sealing since it can be achieved using conventional rotary shaft seals. Standard proprietary rotary shaft seals are readily available for use at high-pressure.

A further advantage of the design according to the present invention is that the pressure loads that act on the inside of the dome shaped closure 110 are carried by the sealing ring 118 rather than the half shafts. This pressure load increases the seating stress between the dome shaped closure 110 and the sealing ring 118 and so acts to improve the sealing.

This method of moving the dome shaped closure 110 into contact with the sealing ring 118 is intended to be used with a range of seal designs each suited to a different application.

Possible sealing ring 118 types include ceramic and lapped hard metal faced, fully supported 0-rings or quad rings in a metal housing.

A water-cooling system can also be applied to the design of the improved valve closure device 100 allowing it to be used in high-temperature applications up to 800 degrees C. In Figure 6, it can be seen that the inner bush 114 rotates anti-clockwise and the outer bush 112 rotates clockwise. This has the effect of moving the dome shaped closure 110 slightly downwards.

In Figure 7, the inner bush 114 continues to rotate anti-clockwise and the outer bush 112 continues to rotate clockwise. The dome shaped closure 110 continues to 25 move downwards.

In Figure 8, the inner bush 114 continues to rotate anti-clockwise and the outer bush 112 continues to rotate clockwise. The dome shaped closure 110 continues to move downwards.

In Figure 9, the inner bush 114 continues to rotate anti-clockwise and the outer bush 112 continues to rotate clockwise. The dome shaped closure 110 is now in its fully downward positon and the valve is fully open and the seal to dome gap increased to maximum extent. The dome shaped closure 110 may then be rotated away from the opening if necessary.

In Figure 10, the dome shaped enclosure is rotated 90 degrees to the fully opened position.

To close the dome shaped closure 110 then the process is repeated until the dome shaped closure 110 is returned to the position shown in Figure 5 and the valve is fully closed and sealed tightly against the sealing ring 118.

The improved valve closure device 100 of the present invention can therefore be used as part of a pneumatic conveying system to provide effective cut-off and sealing at high pressure and/or temperature.

The present invention therefore provides material shut-off and sealing of valves to be used in pneumatic conveying systems or similar bulk solid handling processes where a valve is required to operate at high pressure and/or high temperature. Typical examples are part of a fuel/sorbent feed to high-pressure gasifier and ash discharge valve from a high-pressure gasifier.

Whilst specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention. For example, any suitable type of size and shape of concentric bushes may be used for providing the liner vertical motion to open and close the valve.

Claims

CLAIMS1. A valve closure device comprising: a closure member connected to a first end of at least one substantially vertically oriented shaft; a second end of the at least one substantially vertically oriented shaft located within a first eccentric bush; a second eccentric bush located around the first eccentric bush; wherein on counter-rotating the first and second eccentric bushes the closure member is capable of moving up and down.
2. A valve closure member according to claim 1, wherein the closure member is dome shaped i.e. convex shaped.
3. A valve closure member according to any of claims 1 or 2, wherein there are two substantially vertically oriented shafts connected to the closure member.
4. A valve closure member according to any preceding claim, wherein the first eccentric bush forms an inner bush with the second eccentric bush forming an outer bush with the first eccentric bush being wholly located within the second eccentric bush.
5. A valve closure member according to any preceding claim, wherein the first and second bushes have the same degree of eccentricity.
6. A valve closure member according to any preceding claim, wherein there are two substantially vertically oriented shafts and a pair of first and second eccentric bushes.
7. A valve closure member according to any preceding claim, wherein around the perimeter of the closure member there is a sealing ring which is capable of forming a tight effective seal against the closure member.
8. A valve closure member according to claim 7, wherein the sealing ring extends all the way around the upper part of the periphery of the closure member.
9. A valve closure member according to any of claims 7 and 8, wherein the sealing ring is made from a ceramic and lapped hard metal faced, fully supported 0-rings or quad rings in a metal housing.
10. A valve closure member according to any preceding claim, wherein the closure member is capable of moving from an open to a closed position with no or minimal friction and wear.
11. A valve closure member according to any of claims 7 to 10, wherein the substantially vertically oriented shaft(s) moves at right angles or substantially at right angles to the plane of the sealing ring.
12. A valve closure member according to any preceding claim, wherein the closure member is capable of being opened by counter-rotating the first and second bushes which has the effect of lowering the closure member.
13. A valve closure member according to any preceding claim, wherein during the counter-rotation of the first and second bushes this has the effect of moving the least one or more substantially vertically oriented shaft substantially up or down and hence opening or closing the valve.
14. A valve closure member according to any preceding claim, wherein in use, the first and second (i.e. inner and outer) bushes are rotated at equal speed in opposite directions.
15. A valve closure member according to any preceding claim, wherein the movement of a pair of eccentric bushes is synchronised by gearing to ensure that they counter-rotate at the same speed.
16. A valve closure member according to any preceding claim, wherein an external lay-shaft ensures that the movement of the bushes on each side of the valve are synchronised.
17. A valve closure member according to any preceding claim, wherein a water-cooling system is incorporated into the valve closure device allowing the valve closure device to be used in high-temperature applications up to 800 degrees C.
18. A valve closure member according to any preceding claim, wherein the valve closure device is incorporated into a pneumatic conveying system or similar bulk solid handling processes where a valve is required to operate at high pressure and/or high 20 temperature.
19. A valve closure member according to any preceding claim, wherein the valve closure device is used in part of a fuel/sorbent feed to a high-pressure gasifier and ash discharge valve from a high-pressure gasifier.
20. A pneumatic conveying apparatus or bulk solid handling apparatus comprising a valve closure device, said valve closure device comprising: a closure member connected to a first end of at least one substantially vertically oriented shaft; a second end of the at least one substantially vertically oriented shaft located within a first eccentric bush; a second eccentric bush located around the first eccentric bush; wherein on counter-rotating the first and second eccentric bushes the closure member is capable of moving up and down.
21. A pneumatic conveying apparatus or bulk solid handling apparatus according to claim 20, wherein the valve closure device is as defined in any of claims 1 to 19.
22. A method of opening and closing a valve in a valve closure device comprising: providing a closure member connected to a first end of at least one substantially vertically oriented shaft; providing a second end of the at least one substantially vertically oriented shaft located within a first eccentric bush; providing a second eccentric bush located around the first eccentric bush; wherein on counter-rotating the first and second eccentric bushes the closure member is capable of moving up and down.
23. A method of opening and closing a valve in a valve closure device according to claim 22, wherein the valve closure device is as defined in any of claims 1 to 19.
24. A valve closure member as hereinbefore described and shown in Figures 5 to 8.Amendments to the claims have been made as follows:CLAIMS1. A valve closure device comprising: a closure member connected to a first end of at least one substantially vertically oriented shaft; a second end of the at least one substantially vertically oriented shaft located within a first eccentric bush; a second eccentric bush located around the first eccentric bush; wherein on counter-rotating the first and second eccentric bushes the closure member is capable of moving up and down.2. A valve closure device according to claim 1, wherein the closure member is dome shaped i.e. convex shaped.3. A valve closure device according to any of claims 1 or 2, wherein there are two substantially vertically oriented shafts connected to the closure member.4. A valve closure device according to any preceding claim, wherein the first eccentric bush forms an inner bush with the second eccentric bush forming an outer bush with the first eccentric bush being wholly located within the second eccentric bush.5. A valve closure device according to any preceding claim, wherein the first and second bushes have the same degree of eccentricity.6. A valve closure device according to any preceding claim, wherein there are two substantially vertically oriented shafts and a pair of first and second eccentric bushes. (3) O N 157. A valve closure device according to any preceding claim, wherein around a perimeter of the closure member there is a sealing ring which forms a tight effective seal against the closure member.8. A valve closure device according to claim 7, wherein the sealing ring extends all the way around an upper part of a periphery of the closure member.9. A valve closure device according to any of claims 7 and 8, wherein the sealing ring is made from a ceramic and lapped hard metal faced, fully supported 0-rings or quad rings in a metal housing.10. A valve closure device according to any preceding claim, wherein the closure member moves from an open to a closed position.40) 15 O 11. A valve closure device according to any of claims 7 to 10, wherein the substantially vertically oriented shaft(s) moves at right angles or substantially at right angles to a plane of the sealing ring.12. A valve closure device according to any preceding claim, wherein the closure member is capable of being opened by counter-rotating the first and second bushes which has the effect of lowering the closure member.13. A valve closure device according to any preceding claim, wherein during the counter-rotation of the first and second bushes this has the effect of moving the least one or more substantially vertically oriented shaft substantially up or down and hence opening or closing the valve.14. A valve closure device according to any preceding claim, wherein in use, the first and second (i.e. inner and outer) bushes are rotated at equal speed in opposite directions.15. A valve closure device according to any preceding claim, wherein the movement of the pair of eccentric bushes is synchronised by gearing where the bushes counter-rotate at the same speed.16. A valve closure device according to any preceding claim, wherein movement of the bushes on each side of the valve are synchronised.17. A valve closure device according to any preceding claim, wherein a water-cooling 1.0 system is incorporated into the valve closure device allowing the valve closure device to be used in high-temperature applications up to 800 degrees C. 18. A valve closure device according to any preceding claim, wherein the valve closure device is incorporated into a pneumatic conveying system or similar bulk solid handling processes where a valve is required to operate at high pressure and/or high temperature.19. A valve closure device according to any preceding claim, wherein the valve closure device is used in part of a fuel/sorbent feed to a high-pressure gasifier and ash discharge valve from a high-pressure gasifier.20. A pneumatic conveying apparatus or bulk solid handling apparatus comprising a valve closure device, said valve closure device comprising: a closure member connected to a first end of at least one substantially vertically oriented shaft; a second end of the at least one substantially vertically oriented shaft located within a first eccentric bush; a second eccentric bush located around the first eccentric bush; wherein on counter-rotating the first and second eccentric bushes the closure member is capable of moving up and down.21. A pneumatic conveying apparatus or bulk solid handling apparatus according to I 0 claim 20, wherein the valve closure device is as defined in any of claims 1 to 19.22. A method of opening and closing a valve in a valve closure device comprising: a) providing a closure member connected to a first end of at least one substantially O vertically oriented shaft; providing a second end of the at least one substantially vertically oriented shaft located within a first eccentric bush; providing a second eccentric bush located around the first eccentric bush; wherein on counter-rotating the first and second eccentric bushes the closure member is capable of moving up and down.23. A method of opening and closing a valve in a valve closure device according to claim 22, wherein the valve closure device is as defined in any of claims 1 to 19.24. A valve closure member as hereinbefore described and shown in Figures 5 to 10.