GB2447267A

GB2447267A - Fluid flow valve

Info

Publication number: GB2447267A
Application number: GB0704221A
Authority: GB
Inventors: Andrew Anthony Duggins
Original assignee: Ltd DYNAMIC CONTROLS
Current assignee: Ltd DYNAMIC CONTROLS
Priority date: 2007-03-05
Filing date: 2007-03-05
Publication date: 2008-09-10
Also published as: GB0704221D0

Abstract

A fluid-flow valve 10 comprises a valve body having an inlet 16 and an outlet 18, and a fluid-flow passageway 17 within the valve 10 which extends from the inlet 16 to the outlet 18. A moveable closure member 34 and a valve seat 42 are provided and movement of the moveable closure member 34 towards or away from the valve seat 42 effects opening or closing of the valve 10. The valve seat 42 is removable and is attached to a removable seat attachment member 38 that extends through the valve body away from the valve seat 42 to aid removal of the attachment member 38, along with the valve seat 42, from the valve body.

Description

Fluid flow valve The present invention relates to a fluid-flow valve

comprising a valve body having an inlet and an outlet, a fluid-flow passageway within the valve which extends from the inlet to the outlet, a moveable closure member and a valve seat, such that the passageway extends between the moveable closure member and the valve seat and movement of the moveable closure member towards or away from the valve seat effects closing or opening of the valve.

In previous constructions of such a fluid-flow valve, the valve seat is screwed directly in the valve body, or is an integral part of the valve body. Valve seats wear or erode over time or deposits may build up on the valve seat. Therefore valve seats often require replacing or cleaning. Such prior constructions of fluid-flow valves suffer the disadvantage that in order to remove the valve seat from the valve body, the seat must be unscrewed or, if the seat is corroded onto the valve body, spark eroded. Such removal of the valve seat requires long periods of time, especially in spark erosion, during which the valve is inoperable. Spark erosion may also contaminate the chemicals that normally flow through the valve. Furthermore, in applications involving radioactivity or hazardous chemicals, removal of the valve seat can be dangerous and is difficult when using remote operation tooling, for example, robots.

The present invention seeks to obviate one or more of these disadvantages.

Accordingly, the present invention is directed to a fluid-flow valve having the construction set out in the opening paragraph of the present specification, wherein the valve seat is removable and is attached to a removable seat attachment member that extends through the valve body away from the valve seat to facilitate removal of the attachment member, along with the valve seat, from the valve body. This provides the advantage that when the seat attachment member is removed, the valve seat is also removed without having to detach the valve seat from the valve body separately. It allows for a quicker dismantling of the valve.

Advantageously, the moveable closure member, the valve seat attachment member and the valve seat are part of a removable valve cartridge.

In one configuration, the valve seat may be integral with the seat attachment member. Alternatively, the valve seat is releasably attached to the seat attachment member. This allows for the valve seat to be removed and transported to be serviced without having to transport other parts of the valve. A further advantage is that the valve seat may be replaced without having to replace other parts of the valve.

The seat attachment member is preferably tubular, advantageously surrounding a stem or spindle of the valve, to one end of which stem or spindle is attached the moveable closure member, and the other end of which stem or spindle is coupled to a hand wheel operable to effect longitudinal movement of the stem or spindle.

The valve may include a bellows plate. The latter may incorporate the seat attachment member as an integral part thereof.

Alternatively, the seat attachment member may be attached to the bellows plate, advantageously to a lower part of the bellows plate.

The valve seat may be attached to the seat attachment member by a clip connection. This provides a secure and readily releasable method of attaching the valve seat to the seat attachment member. The clip connection may comprise a plurality of resilient snap-fit portions.

In an alternative embodiment, the valve seat may be mounted on the seat attachment member by a screw thread connection. The screw threads provide a secure method of attaching the valve seat to the seat attachment member.

The seat attachment member may be in the form of a valve seat cage.

An example of a fluid-flow valve embodying the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is an elevational side view of a fluid-f low valve embodying the present invention; Figure 2 is an axial-sectional view along the line A-A of the valve shown in Figure 1; Figure 3 is a perspective cut-away view of the valve show in Figure 1; and Figure 4 is a perspective view ot the valve shown in Figure 1 with a cartridge thereof removed.

A fluid-flow valve 10 shown in Figures 1 to 4 comprises a valve body 12, along an intended upright axis of which is machined a cartridge cavity 14. The valve body 12 further comprises a machined inlet 16 and a machined outlet 18, which are in communication with one another via a lower part of the cartridge cavity 14 constituting a fluid-flow passageway 17. That part of the valve body 12 which defines the passageway 17 has a shoulder 22.

A lower part of a cartridge 24 is inserted into the cartridge cavity 14. The cartridge 24 comprises a bellows plate 26, which is received in a valve bonnet 28.

Both the bellows plate 26 and the valve bonnet 28 are formed with axially extending through-holes. A flange 29 integral with a lower part of the valve bonnet 28 is releasably secured to a flange 291 integral with an upper part of the valve body 12 by way of nuts 292 and bolts 293. A flange 294 integral with a lower part of the bellows plate 26 is sandwiched between inner portions of the flanges 29 and 291 in a secure fashion. An o' ring 295 provides a fluid tight seal between the flange 294 and the flange 291.

The cartridge further comprises an axially extending stem or spindle 30, so that it is co-axial with and extends through the machined through-holes of both the bellows plate 26 and the valve bonnet 28.

The upper end of the stem 30 passes through a central aperture in a hand wheel 32. The hand wheel 32 is secured rotatably in the valve bonnet 28 to inhibit vertical displacement of the hand wheel 32. The central aperture of the hand wheel 32 is provided with a bush having an internal screw thread, which engages with a corresponding external section of screw thread on the upper end of the stem 30. A closure member 34 of generally circular cross-section is attached to the lower end of the stem 30. The closure member 34 is tapered at its lower end.

A seal is provided between the stem 30 and the valve bonnet 28 at an upper end thereof by way of gland packing 35 between those parts. The gland packing 35 is held in place via a packing sleeve 350 by means of a gland flange 351 fastened to lugs 352 provided at the upper end of the valve bonnet 28 via nuts 353 and bolts 354.

One end of a tubular bellows 36 is sealingly attached to the underside of the bellows plate 26. The bellows 36 extend downwardly co-axially with and surrounding the stem 30 and the other end of the bellows is attached to the stem at a position above the closure member 34. An upper end of a valve seat member in the form of a tubular valve seat cage 38 is attached to a lower part of the bellows plate 26 so that a lower part of the bellows 36 is surrounded by the valve seat cage 38. The lower end of the seat cage 38 is provided with

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one half of a clip arrangement 40. A ring shaped valve seat 42 of generally circular cross-section is provided with a second half of the clip arrangement 40 by which the valve seat 42 is secured to the lower end of the seat cage 38 coaxially with the valve body 12.

The through-hole in the bellows plate 26 is generally hexagonal in shape, and the cross-section of the stem or spindle 30 at this level is also hexagonal so that the stem 30 can slide axially through the through-hole but cannot rotate relative thereto.

The valve seat 42 having an outwardly protruding flange 44 may be seated on the shoulder 22, the diameter of the flange 44 being such to facilitate this. Beneath the flange 48, the diameter of the valve seat 42 corresponds to that of the lower part 20 of the valve body 12 so as to form at least a close fit therewith. At a position below the flange 44, the valve seat is provided with a circumferential groove 46 on its external surface. An a' ring seal 48 is located in the groove 46. Thus the valve seat 42 fits into the part 20 of the valve body 12 and the o' ring seal 48 provides a fluid-tight seal between the inside wall of the valve body 12 and the valve seat 42.

Rotation of the hand wheel 32 in a clockwise sense will raise the spindle 30 and with it the closure member 34 into an open position whereas rotation of the hand wheel 32 in an anti-clockwise sense will lower the spindle 30 and with it the closure member 34 into a closed position.

When in an open position, fluid flows through the fluid-flow path, more specifically, into the inlet 16, through the valve seat 42 located in the part 20 of the S valve body 12, and out through the outlet 18. Rotating the hand wheel 32 clockwise effects downward axial movement of the spindle or stem 30 due to the engaging screw threads of the hand wheel 32 and the stem 30. The stem 30, and the closure member 34 connected to the end thereof, is moved towards the valve seat 42 until the closure member 34 contacts the valve seat 42 and effects a seal to prevent the flow of fluid from the inlet 16 to the outlet 18.

In order to replace the valve seat 42, the valve bonnet 28 is unbolted from the valve body 12. The whole valve cartridge 24, which includes both the closure member 34 and the valve seat 42, is then removed from the valve body 12, as shown in Figure 4. Using a suitable tool (not shown) to unclip the clip arrangement 40, the valve seat 42 is disconnected from the seat cage 38 and cleaned before replacement. Alternatively, the valve seat 42 may be disposed of and replaced by a new, or better condition, valve seat 42. The lower part of the cartridge 24 is then re-inserted into the valve body 12 and valve bonnet 28 is reattached to the valve body 12.

It will be appreciated that the binding between the two halves of the clip arrangement 40 must be of sufficient strength to overcome any corrosion that may have bound the valve seat 42 into the valve body 12.

Otherwise the valve seat 42 will become detached within the valve body 12 and may require spark erosion to remove it. Clearly, this also applies to all the connections from the hand wheel 32 down to the seat cage 38.

The valve seat 42 in the above example may be constructed from polished stainless steel. However, any other suitable material may be used depending on the purpose of the valve.

It will be appreciated that it may be desirable to have a number of cartridges for a single valve body so that a first cartridge may be removed from the valve body and a second cartridge immediately inserted to reduce the time for which the valve in inoperable. The first cartridge, or just the valve seat thereof, may then be serviced, cleaned and/or repaired and held in stock until the second valve cartridge requires servicing. It may be desirable to discard the first cartridge, or the valve seat thereof, rather then service, clean and/or repair it.

Numerous variations and modifications to the illustrated construction may occur to the reader familiar with the art without taking the valve outside of the scope of the invention. For example, it may be desirable to omit the bellows. Furthermore, the bellows and/or the valve bonnet may be separable from the cage, allowing a two or three stage process for removing the valve seat, firstly by removing the valve bonnet, then the bellows plate if necessary, and finally the cage with seat.

Instead of a straight' valve as illustrated, a right angled' valve may be used wherein the inlet and outlet are at right angles to one another, for example with the inlet extending axially in relation to the valve.

The stem or spindle 30 may be extended, and surrounded by a suitably protecting sleeve (not shown), to provide easier access to the hand wheel 32 in some applications.

Claims

Claims: 1. A fluid-flow valve comprising a valve body having an inlet

and an outlet, a fluid-flow passageway within the valve which extends from the inlet to the outlet, a moveable closure member and a valve seat, such that the passageway extends between the moveable closure member and the valve seat and movement of the moveable closure member towards or away from the valve seat effects closing or opening of the valve, wherein the valve seat is removable and is attached to a removable seat *:*::* attachment member that extends through the valve body away from the valve seat to facilitate removal of the attachment member, along with the valve seat, from the * valve body.

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2. A fluid-flow valve according toc1aim 1, in which *..: * the moveable closure member, the valve seat attachment *5.5** * member and the valve seat are parts of a removable valve cartridge.
3. A fluid-flow valve according to claim 1 or claim 2, in which the valve seat is integral with the seat attachment member.
4. A fluid-flow valve according to claim 1 or claim 2, in which the valve seat is releasably attached to the seat attachment member.
5. A fluid-flow valve according to any preceding claim, in which the seat attachment member is tubular.
6. A fluid-flow valve according to claim 5, in which the seat attachment member surrounds a stem or spindle of the valve.
7. A fluid-flow valve according to claim 6, in which the moveable closure member is attached to one end of the stem or spindle, the other end of which stem or spindle is coupled to a hand wheel operable to effect longitudinal movement of the stem or spindle.
8. A fluid-flow valve according to any preceding claim, in which the valve includes a bellows plate.
9. A fluid-flow valve according to claim 8, in which the bellows plate incorporates the seat attachment member as an integral part thereof.
10. A fluid-flow valve according to claim 8, in which the seat attachment member is attached to the bellows * S * S * * plate. ***
11. A fluid-flow valve according to claim 10, in which **** * the seat attachment member is attached to a lower part of I.....

* the bellows plate.
12. A fluid-flow valve according to any preceding claim, in which the valve seat is attached to the seat attachment member by a clip connection.
13. A fluid-flow valve according to claim 12, in which the clip connection comprises a plurality of resilient snap-fit portions.
14. A fluid-flow valve according to any one of claims 1 to 11, in which the valve seat is mounted on the seat attachment member by a screw thread connection.
15. A fluid-flow valve according to any preceding claim, in which the seat attachment member is in the form of a valve seat cage.
16. A fluid-flow valve substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. * .* * * * * ** **** * * **** ** S * S* * I.

S S..

S I *