GB2265967A - Attaching seal retaining rings to valves - Google Patents

Abstract

In a butterfly or ball valve, the seal assembly 7 is held in position on the valve housing by means of a retaining ring 8. The ring is maintained on the housing by one or more pins 11, which extend tangentially to the ring and co-operate with formations on the housing and the ring. The housing formations may be lugs 12, 13 formed integrally with the valve shaft journal bosses 5, 6, each lug being provided with a lip 15, and the ring formation may be an annular recess 22. In use the central portion of the pin engages with the recess 22 and the ends of the pin engage with the lip 15 to prevent axial movement of the ring relative to the housing. Alternatively, the housing formation can be provided on a radially inwardly facing part of the valve housing. The retaining ring may have a recess 9 to accommodate a projection on a pipe flange. <IMAGE>

Description

BUTTERFLY AND BALL VALVES This invention relates to butterfly and ball valves of the kind comprising a valve housing, a rotatable valve member housed in a through-bore in the housing, and an annular seal assembly carried by the housing and adapted to seal with the valve member at least when the valve member is in a closed position.

Such a valve will hereinafter be referred to as a valve of the kind set forth.

The seal assembly of a valve of the kind set forth generally comprises an annular seat member which seals directly with the valve member in the closed position thereof, the seat member being located in place in the housing by an annular seat retaining ring which in general is housed within an annular recess in one end of the housing, the annular recess being defined by a counterbore to the main housing bore.

It is necessary in use of the valve to effect a direct or indirect seal between the seat retaining ring and the mating flange of adjacent pipework to which the valve is secured. Some form of gasket is sandwiched between the outer face of the retaining ring and the mating flange face of the pipework.

Whilst the valve is in storage or in transit it is very desirable that the components cannot become displaced from their assembled positions. Some securing means is therefore required to hold captive the seat retaining ring which might otherwise fall from the housing.

Various retaining ring securing means have been proposed. A series of axially extending screws may be provided to extend through the retaining ring into the valve housing, but the holes in the retaining ring to receive the screws interrupt the gasket face of the retaining ring and can reduce the efficiency of sealing to the adjacent pipework.

In our Specification no. GB 2t306SS z we have disclosed a retaining ring securing means in the form of a wire polygon, circumferentially spaced portions of the wire engaging respectively with annular grooves in the confronting cylindrical surfaces of the retaining ring and valve housing. Thus the valve housing is provided with a counterbore to receive the retaining ring, the bore wall of the counterbore is machined with an internal annular groove, and the radially outer cylindrical surface of the retaining ring is machined with a further annular groove.This arrangement has the disadvantage that restrictions are imposed upon the maximum diameter of the retaining ring, and therefore the diameter of the butterfly valves disc that can be accommodated within a valve housing of given external dimensions, because a certain radial thickness of valve housing is required to define the counterbore wall for providing the internal annular recess.

The present invention can facilitate the use of a valve housing which does not have a bore or counterbore to receive the retaining ring. That is, the retaining ring may, if desired be held captive on one end face of the valve housing, The present invention is concerned with the use of a tangential pin as a retaining ring securing means.

According to one aspect of the present invention, in a valve of the kind set forth a retaining ring is held captive to the valve housing by at least one pin extending tangentially of the retaining ring, the pin co-operating with a first formation provided on or in a substantially cylindrical, radially outwardly facing face of the retaining ruing, and with a second formation provided on or in a confronting radially inwardly facing surface of a respective housing lug projecting axially from a corresponding face of the housing towards which the retraining ring is clamped in use.

The lug is preferably positioned generally in line with the pivotal axis of the valve member such that the lug can be readily accommodated on a portion of f the housing in which is journalled an operating shaft, or a stub shaft.

The retaining ring is conveniently sealed to the valve housing by a retaining ring sealing ring sandwiched between the retaining ring and said end face of the housing.

The first formation may be a localised formation on the retaining ring, but preferably the first formation comprises an annular recess provided on an external substantially cylindrical surface of the retaining ring Such a recess can be economically machined in the retaining ring, and can avoid the need for any circumferential alignment of the retaining ring on assembly of the retaining ring to the valve housing.

The second formation is preferably a part-annular recess provided in said radially inwardly facing surface of the housing lug. Such a recess can be turned in the housing as part of a machining procedure associated with the rotary machining of the corresponding housing end to receive the annular seal assembly and retaining ring. This avoids a separate milling operation on the lug1 which would require re-mounting of the valve housing.

Said radially inwardly facing surface of the lug is preferably a part-cylindrical surface complementary to the radially outer surface of the retaining ring such that said surfaces co-operates together to locate the retaining ring substantially co-axially of the housing bore.

There are preferably two dLametrically-opposed such lugs and preferably two such pins co-operating respectively with the lugs, and both lugs are formed with a part-cylindrical surface to locate the retaining ring co-axially of the housing bore The second formation is preferably a part-annular recess formed in said part-cylindrical radially inwardly facing surface of the lug, and the pin is a substantially straight pin which engages with the walls of said part-annular recess at opposite circumferential ends of the recess, and at an intermediate position with the walls of the external annular recess in the retaining ring By suitable choice of the diameter of the pin a sufficiently tight wedging engagement with the pin can be achieved to retain the retaining ring captive during transit.

The recess in the lug or that in the retaining ring can be made sufficiently wide in the axial direction of the valve body to accommodate some axial movement of the retaining ring relative to the valve body during clamping-upr in use, of the valve body to the mating flange of the adjacent pipework. The pin can slide or roll to accommodate such relative axial movement of the retaining ring and valve housing.

The relatively wide, unobstructed face of the retaining ring for mating with the adjacent pipework flange enables the flange to be provided with an annular male or female formation to mate with DIN standard flanges as currently specified for some applications on the continent of Europe.

According to a second aspect of the invention, in a valve of the kind set forth a retaining ring is held captive to the valve housing by at least one pin extending tangentially of the retaining ring, the pin cooperating with a first annular, or part-annular recess provided in a radially outwardly facing face of the retaining ring, and with a second part-annular recess provided in a radially inwardly facing face of the valve. housing.

A butterfly valve of the kind set forth will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of the valve showing the disc in a fully closed condition, the lower half being sectioned on the axis of the operating shaft 2, that is on the line 1-1 of Figure 2; Figure 2 is an axial, end view of the valve looking from the right in Figure 1, the valve being locally sectioned on the line 2-2 of Figure 1 Figure 3 is an enlargement of the lower local section of Figure 2, showing the cooperation between one of the pins and the retaining ring and housing key; Figure 4 is an enlarged view corresponding to Figure 2 but of the valve housing only, and is a section on the line 4-4 of Figure 6;; Figure 5 is an enlarged radial cross-section of the retaining ring; Figure 6 is a side elevation of the valve housing, partially sectioned on the line 6-6 of Figure A; and Figure 7 is an enlargement of the indicated scrap section of Figure 6 The butterfly valve illustrated comprises a cast and machined valve housing 1 having a substantially cylindrical through-bore in which is pivotally mounted a butterfly valve disc 2 by means af an operating shaft 3 to which the disc 2 is pinned by a pair of pins ", the opposite ends of the shaft 3 being journalled in diametrically opposed housing bosses 5, 6.

An annular seal assembly 7, generally as shown in our Specification No. GB5voS8Z36at Figure 3 , is adapted to seal with the part-spherical radially outer surface of disc 2 when the disc 2 is turned to the position shown in Figure 1 in which the disc extends transversely across the housing bore. The seal assembly 7 is clamped in place in use against the valve housing 1 by the usual expedient of an annular retaining ring 8. fn use of the valve the clamping of the valve body I to the adjacent pipework by means of bolts extending through housing ears 9 results in an axial force being applied against the retaining ring 8 by the flange, not shown, of the adjacent pipework.

The retaining ring 8 is provided, in this case, with a wide annular groove 9 in the axially outer face thereof to receive the male projection on a DIN standard pipe flange as used on continental European pipes, but the retaining ring could instead be provided with an annular projection to mate with a corresponding recess on a pipe flange as also used on some DIN standard pipe flanges. The present invention assists in facilitating the provision of annular access 9, or a corresponding projection, since the axially outer face 10 of the retaining ring is unobstructed.

A securing means for holding captive the seat retaining ring 8 to the valve body 1 comprises a pair of straight roll pins 11 which each cooperate with formations, to be described, on both the retaining ring 8 and valve housing 1. The housing 1 is provided with two axially directed lugs 12 and 13 integral with the respective housing bosses 5 and 6 and positioned radially outward of the annular housing surface 14 against which the retaining ring 8 is urged in use by the valve body to pipe clamping forces.As shown in Figures 1 and 4, the lugs 12 and 13 are of substantially oblong-rectangular shape, as viewed in an axial direction of the valve body 1, except that the surface 15 adjacent to the returning ring is an internal part-cylindrical surface formed with a part-annular recess 16 to cooperate with the opposite axial ends of the respective pin 11.

The part-cylindrical surface 15 is defined by a radially inwardly projecting, arcuate lip 17, by a rounded internal corner 18, Figure 7, and by an axially extended internal cylindrical face 19 extending to a corner 20 where the face 19 meets the radial face 14.

The arcuate lips 17 of the lugs 12, 13 are dimensioned such that the retaining ring is a close fit therebetween, the radially outer cylindrical surface 21, Figure 5, of the retaining ring being of slightly smaller diameter than the corresponding diameter defined by the opposed lugs 12, 13. The lips 17 thus act to centre the retaining ring with respect to the housing axis and hence with respect to seat assembly 7.

The recess 16 on lugs 12, 13 is the formation on the housing with which pins 11 cooperate. The formation on the ring 8 with which the pins 11 cooperate is an external annular recess 22, which extends entirely around the retaining ring surface 21 and is of a cross-section complementary to substantially half of roll-pin 11 The roll pins 11 engage tangentially with the retaining ring 8, the pins 11 at their middle tightly fitting the recess 22, as shown in Figure 3, whilst the end regions of the pins 11 bear on the cylindrical face 19.

Since the recess 16 in lugs 12, 13 is axially extended compared with recess 22, the pins 11 are able to move axially of the valve housing 1 during clamping of the valve housing 1 to the flange of adjacent pipework, the clamping force urging the retaining ring 8 axially towards the surface 14 on housing 1 thereby to effect a seal between the housing 1 and retaining ring 8 by compression of a gasket 23, Figure 1 Since the arcuate surface 15 is centred on the axis of the valve housing, surface 15 can be machined on the same machine as is used to machine the housing surface 14 thereby avoiding the need for a separate milling operation which would have been necessary if surface 15 had been essentially flat.

Claims (11)

1. A valve of the kind set forth in which a retaining ring is held captive to the valve housing by at least one pin extending tangentially of the retaining ring, the pin co-operating with a first formation provided on or in a substantially cylindrical, radially outwardly facing face of the retaining ring, and with a second formation provided on or in a confronting radially inwardly facing surface of a respective housing lug projecting axially from a corresponding face of the housing towards which the retaining ring is clamped in use.

2. A valve as claimed in claim 1, in which the lug is located on a portion of the housing in which is journalled an operating shaft, or a stub shaft bearing the valve member.

3. A valve as claimed in claim 1 or claim 2 in which the first formation comprises a surface which is concentric with the said radially outwardly facing face of the retaining ring.

4. A valve as claimed in any one of the preceding claims in which the first formation comprises an annular recess in said radially outwardly facing face of the retaining ring.

5. A valve as claimed in any one of the preceding claims in which the second formation comprises a part-annular recess provided in said radially inwardly facing surface of the housing lug.

6. A valve as claimed in claim 5 as appended to claim 4 in which the pin is a substantially straight pin which engages with the walls of said part-annular recess in the housing lug at opposite circumferential ends of the recess, and at an intermediate position with the walls of said annular recess in the retaining ring.

7. A valve as claimed in any one of the preceding claims in which said radially inwardly facing surface of the lug is a part-cylindrical surface complementary to an outer radial surface of the retaining ring such that said surfaces co-operate together to locate the retaining ring substantially co-axially of the housing bore.

8. A valve of the kind set forth in which there are two diametrically-opposed lugs and two pins co-operating respectively with the lugs in accordance with any one of the preceding claims, both lugs being formed with a part-cylindrical surface to locate the retaining ring co-axially of the housing bore.

9. A valve as claimed in the combination of claims 4 and 5, or in any one of claims 6 to 8 as appended thereto in which the recess in the lug or that in the retaining ring is made sufficiently wide in the axial direction of the valve body to accommodate some axial movement of the retaining ring relative to the valve body during clamping-up, in use, of the valve body to the mating flange of the adjacent pipework.

10. A valve of the kind set forth in which a retaining ring is held captive to the valve housing by at least one pin extending tangentially of the retaining ring, the pin co-operating with a first annular, or part-annular recess provided in a radially outwardly facing face of the retaining ring, and with a second part-annular recess provided in a radially inwardly facing face of the valve housing.

11. A valve substantially as described herein with reference to the accompanying drawings.