A valve with a sealing ring

Abstract

The invention relates to a valve (1), comprising a valve body (2) delimiting a flow channel (3), a closure member (4), and a sealing ring (5). The sealing ring (5) has a first section (8) and a second section (9) extending from the first sealing area (7) separated from each other towards a second sealing area (10) located in a cavity (11) formed in the other one of the valve body (2) and the closure member (4). To ensure controlled yielding of the material in the sealing ring in a way which prevents leakage also during high pressure, the material thickness of the first section (8) and of the second section (9) decreases at discontinuity locations (12) of the first (8) and the second section (9) in a direction from the first sealing area (7) towards the second sealing area (10).

Description

A^VALVE^WITH^A^SEALING^RING BACKGROUND^OF^THE^INVENTION^ FIELD^OF^THE^INVENTION^

[0001] ^ This invention relates to a valve with a sealing ring.DESCRIPTION^OF^PRIOR^ART

[0002] ^ In relation to industrial fluid transport and processing, an increasingmarket demand exists for solutions capable of operating under very high fluidpressures. Valves, for example butterfly valves, used in these applications thereforealso need to be designed for increasingly high operating pressures, whilesimultaneously fulfilling continuously stricter requirements for shutoff tightness.

[0003] ^ As the operating pressure of a valve is increased, problems typicallyfirst start occurring at a sealing interface between the valve body and the valveclosure member, for example a disc of a butterfly valve. More precisely, leakagestypically start occurring after surpassing a certain pressure threshold as a result ofelastic or plastic deformation of the valve sealing ring, or valve seat, used forsecuring the sealing interface between the valve body and the closure member.Said deformation may cause temporary or permanent loss of seal integrity betweenthe sealing ring and the valve body or the sealing ring and the valve closuremember. SUMMARY^OF^THE^INVENTION

[0004] ^ An object of the present invention is to alleviate the above-mentioneddrawbacks and to provide a valve structure suitable for use under high operatingpressures. This object is achieved with a valve according to independent claim 1.

[0005] ^ By providing a valve with a sealing ring having a first section and asecond section, the first section and the second section can be provided withdiscontinuity locations at which the material thickness of the first section and ofthe second section decreases. This makes it possible to obtain a sealing ring whichchanges shape in a controlled manner. This ensures a tight sealing interfacebetween the valve body and the valve closure member under a wide range of operating pressures.

[0006] ^ Preferred embodiments of the invention are disclosed in the dependentclaims.BRIEF^DESCRIPTION^OF^DRAWINGS

[0007] ^ In the following the present invention will be described in closer detailby way of example and with reference to the attached drawings, in which

[0008] ^ Figure 1 illustrates a cross-cut section of a first embodiment of a valve,

[0009] ^ Figure 2 illustrates a partial view of the cross-cut section of Figure 1,

[0010] ^ Figure 3 illustrates a magnified cross-cut section of a sealing ring and acavity of the valve of Figure 1, and

[0011] ^ Figure 4 illustrates a magnified cross-cut section of a sealing ring and acavity of a second embodiment of the valve. DESCRIPTION^OF^AT^LEAST^ONE^EMBODIMENT

[0012] ^ Figure 1 illustrates a cross-cut section according to a first embodimentof a valve 1, which in this example is a butterfly valve, though in otherimplementations other types of valves may be utilized. The valve 1 comprises avalve body 2 delimiting a flow channel 3 and a closure member 4 arranged to bemoved between a fully closed position preventing flow through the flow channel 3,as illustrated in Figure 1, and a fully open position allowing flow through the flowchannel. In said example, the closure member 4 is a disc of a butterfly valve whichmay be moved between the fully closed position and the fully open position byrotation. In other embodiments of the valve 1, the closure member 4 may also bearranged to be moved along a linear trajectory, for example.

[0013] ^ As seen in the example of Figure 1, the valve 1 also comprises ametallic sealing ring 5 that forms a sealing interface 6 between the closure member4 and the valve body 2 in the fully closed position of the valve, such that fluid flowthrough the flow channel of the valve is prevented. More precisely, the sealing ring5 forms a lining around an outer perimeter of the closure member 4 in the fullyclosed position to sealedly cover any gaps otherwise remaining between the valvebody 2 and the closure member 4. Consequently, no flow of fluid can pass thesealing interface 6 in the fully closed position. The sealing ring 5 is partially arranged in a cavity 11 which, depending on the valve configuration, may be provided to the valve body 2, as in the case of the embodiment illustrated in Figure1, or it may be provided to the closure member 4. In order to ensure that theillustrated valve remains fluid tight in the fully closed position of the closure member also when the operating pressure is high, the sealing ring 5 ismanufactured of a metallic material, for example steel.

[0014] ^ To illustrate the sealing arrangement of the valve 1 in Figure 1 in moredetail, Figure 2 illustrates a partial view of the cross-cut section of Figure 1. Asbetter seen in Figure 2, the sealing ring 5 in this example has a first sealing area 7arranged to tightly contact the closure member 4 in the fully closed position, but once the closure member 4 is being moved towards the open position to allow fluid flow, contact between the first sealing area 7 and the closure member 4 is gradually lost. More precisely, the first sealing area 7 is provided as a rounded surfaceextending at an inner circumference of the sealing ring 5 such that when the closuremember 4 is moved to the fully closed position, a sealing line is formed betweenthe first sealing area 7 and the outer perimeter of the closure member 4. Inembodiments of the valve 1 in which the cavity receiving the sealing ring 5 isprovided to the closure member 4, the first sealing area 7 may also be provided toan outer circumference of the sealing ring 5 to tightly contact the valve body 2 andthereby to form a sealing line extending around a circumference of the flow channel3.

[0015] ^ As best seen in the example of Figure 2, the sealing ring 5 also has afirst section 8 and a second section 9 that extend from the first sealing area 7separated from each other. Consequently, the sealing ring is generally U-shaped incross-section. However, in some variations of the valve 1 it may be preferable toprovide only a part of the sealing ring 5 with the U-shaped cross-section asdescribed. In other words, in these variations the sealing ring 5 may not berotationally symmetric as the shape of the cross-section changes along thecircumference the sealing ring 5. The sections 8, 9 extend towards a second sealingarea 10 located in the cavity 11, the cavity in said example being formed in the valvebody 2. In other words, in the illustrated example the second sealing area 10 islocated in proximity of the free ends of the first 8 and the second section 9 whichare located at a distance from the first sealing area 7, wherein a sealing line isformed between each of the sections 8, 9 and adjacent wall of the cavity 11 at thesecond sealing area 10. In embodiments of the valve 1 in which the first sealingarea 7 of the sealing ring 5 is arranged to contact the valve body 2, as opposed tocontacting the closure member 4, the cavity 11 may be formed in the closuremember 4. In other words, the placement and orientation of the sealing ring 5 andthe cavity 11 in relation to each other may be reversed as compared to theillustration of Figure 2.

[0016] ^ In the examples of Figures 1 and 2, the valve 1 also comprises a clampring 22 connecting to the valve body 2 such that the cavity 11 is defined betweenthe valve body 2 and the clamp ring 22 together. In this configuration, the sealinginterface 6 extends between the valve body 2 and the clamp ring 22. More precisely,the clamp ring 22 is placed to surround the flow channel 3, and the connectionbetween the valve body 2 and the clamp ring 22 may be established usingmechanical fasteners, for example. With the arrangement as described, the cavity11 may be accessed by detaching the clamp ring 22 from the valve body 2, therebyenabling the sealing ring 5 to be installed during assembly or replaced duringmaintenance of the valve. The clamp ring 22 may also provide a compressive forceto the sealing ring 5 for holding the sealing ring 5 in place during use and securingthe sealing interface 6 under high fluid pressure conditions.

[0017] To further illustrate the structure of the sealing ring 5 according to theembodiment of Figures 1 and 2, Figure 3 illustrates a magnified cross-cut sectionof the sealing ring 5 and the cavity 11. As best seen in Figure 3, in this example boththe first section 8 and the second section 9 are provided with discontinuitylocations 12, wherein a material thickness of the first 8 and of the second section 9decreases at discontinuity locations 12 in a direction from the first sealing area 7towards the second sealing area 10. In the example of Figure 3, correspondingdiscontinuity locations 12 of the first 8 and of the second section 9 are locatedsymmetrically such that the pattern created to the first section 8 mirrors thatcreated to the second section 9. In this context, the term ’corresponding’ refers toeach locationally matching pair of the discontinuity locations 12 at the first 8 andthe second section 9. However, positioning of the discontinuity locations 12 at thefirst 8 and the second section 9 may not be identical in other configurations of thevalve 1, as variation of the positioning and thereby intentional asymmetry of thesections 8, 9 may be preferred in certain applications. The discontinuity locations12 may also be provided to only one of the first 8 and the second section 9 in some embodiments.

[0018] By providing the first section 8 and the second section 9 with thediscontinuity locations 12 at which the material thickness of the sections decreasestowards the second sealing area 10, yielding behavior of the sealing ring 5 duringuse may be precisely controlled. In more detail, by precisely positioning anddimensioning the discontinuity locations 12 and by thereby adjusting the materialthickness of the first and the second section 8, 9, concentration of mechanical stressto one location of the sealing ring 5 may be prevented. In conventional sealing ringshaving a U-shaped cross-section, said location of stress concentration is typicallythe inner curve of the U-shape located between sections of the sealing ring, andtherefore yielding of the sealing ring typically first occurs in this area as theoperating pressure of the valve is increased. By providing the discontinuitylocations 12 as described above, a more even distribution of the mechanical stressacross the length of the sealing ring 5 cross-section may be provided, and therebyalso more even distribution of deformation of the sealing ring 5.

[0019] In the illustrated example, the first section 8 and the second section 9have inner planar surfaces 23 facing each other at the discontinuity locations 12.At the outer surfaces 18, 20 of the first section 8 and the second section 9 thesurfaces are not planar at the discontinuity locations, but instead a steplike shape has been implemented. It is more easy to machine the shape of the outer surfaces than of the inner surfaces of the sections, due to which a more precise change inthe material thickness can be obtained. This ensures that the yielding of thesections 8 and 9 occurs exactly as desired to obtain a fluid tight sealing during allconditions. However, in some embodiments of the sealing ring 5, the positioning ofthe surfaces to which the discontinuity locations 12 are provided may also beenreversed. That is, the planar shape may also be provided to the outer surfaces 18, 20 of the first 8 and the second section 9 and the discontinuity locations 12 provided to their inner surfaces. Based on the requirements set by each use case, some of the discontinuity locations 12 may also be provided to the inner surfacesand some to the outer surfaces 18, 20 of the first 8 and the second section 9. At theouter surfaces 18, 20, the operating pressure typically causes tensional forces to beformed, whereas at the inner surfaces the forces are typically compressive forces.

[0020] From Figure 3 it can be seen that at the discontinuity locations 12steps have been formed. However, to avoid unintentional concentration of forces at these steps, a more rounded shape is provided to the steps.

[0021] The exact number and shape of the discontinuing locations 12 in thefirst section 8 and in the second section 9 may vary depending on theimplementation, for example based on the end size of the sealing ring 5. In theillustrated example three discontinuity locations 12 have been provided in eachsection, though in other implementations the number of discontinuity locationsmay be higher or lower. The change in the material thickness at the discontinuitylocations 12 will cause the discontinuity locations to work similar as hinges, inother words, bending of the sections will occur mainly at these locations.

[0022] From Figure 3 it can also be seen that the first section 8 comprises afirst sealing protrusion 15 arranged to tightly contact a first wall 17 of the cavity11 at the second sealing area 10. Similarly, the second section 9 comprises a secondsealing protrusion 16 arranged to tightly contact the second wall 14 of the cavity11 opposite to the first wall 17 at the second sealing area 10. In this example thesesealing protrusions 15 and 16 will prevent any fluid from passing the sealing viathe part of the cavity 11 which is located to the left of the sealing protrusions 15 and 16 in Figure 3. In other embodiments of the sealing ring 5, the sealing protrusion 15, 16 as described may be provided to only one of the first 8 and the second section 9. It is also possible that either one or both of the first 15 and the second sealing protrusion 16 are provided to the corresponding first wall 17 and the second wall 14 of the cavity 11 instead of the sections 8, 9 of the sealing ring 5. In this configuration, the protrusions 15, 16 will also provide a tight contact between the sections 8, 9 and the walls of the cavity 11, and thereby prevent anyfluid passing the sealing as described above in relation to Figure 3.

[0023] Due to contact between the first sealing protrusion 15 and the firstwall 17 of the cavity 11, the outer surface 18 of the first section 8 is separated fromthe first wall 17 of the cavity 11 by a gap 19. In Figure 3, this gap 19 extends fromthe flow channel 3 to the first sealing protrusion 15. In some embodiments theminimum distance between the outer surface 19 and the first wall 17 may be about0,2 mm to 0,4 mm, for instance. An advantage with this gap is that it facilitatescontrolled yielding of the sealing ring 5 to some extent, said yielding enabling thesealing ring to accommodate movement of the closure member 4 in flow directiondue to the operating pressure in the fully closed position. More precisely, thesealing ring 5 may yield upwards until a contact occurs between the upper outersurface 18, namely the outer surface of the first section 8, and the first wall 17 ofthe cavity. At that stage additional support provided by the first wall 17 preventsthe sealing ring from moving too much upwards in Figure 3. Said arrangementcorresponds to the flow to open -configuration of the valve 1, wherein the operating pressure caused by the fluid flow acts towards pushing the closure member 4 towards an open position.

[0024] From Figure 3 it can also be seen that the sealing ring 5 comprises asupport protrusion 13 extending from the second section 9 towards the secondwall 14 of the cavity 11 in vicinity of the first sealing area 7. This support protrusionensures that when the sealing ring is subjected to forces from above in Figure 3, such as due to fluid pressure or due to contact between the first sealing area and the closure member 4, these forces can cause only a limited yielding of the sealing ring 5, as the support protrusion 13 will contact the lower second wall of the groove 14, and prevent that the righthand part of the sealing ring 5 with the first sealingarea 7 moves too much downwards in Figure 3. Said arrangement is particularlysuitable for use in the flow to close -configuration of the valve 1, wherein theoperating pressure caused by the fluid flow acts towards pushing the closure member 4 towards a closed position.

[0025] By utilizing the support protrusion 13 as described, displacement ordistortion of the sealing surfaces of the sealing ring 5 as a consequence of collapsingmay be prevented. In case of the example of Figure 3, for example, said collapsingrefers to a situation in which the sealing ring 5 is compressed so strongly by theclosure member 4, which due to the operating pressure is pressed against thesealing ring 5, that plastic deformation occurs in the material of the sealing ring.

[0026] Figure 4 illustrates a magnified cross-cut section of a sealing ring anda cavity of a second embodiment of the valve. The embodiment of Figure 4 is verysimilar to the one explained in connection with Figures 1 to 3. Therefore, in the following the embodiment of Figure 4 will be mainly explained by pointing out the differences between these embodiments.

[0027] In Figure 4 the outer surface 19 of the second section 9 is not providedby a support protrusion, as illustrated in Figure 3. Instead, such a support protrusion is provided to the second wall 14 of the cavity 11.

[0028] It is to be understood that the above description and theaccompanying figures are only intended to illustrate the present invention. It will be obvious to a person skilled in the art that the invention can be varied and modified without departing from the scope of the invention.

Claims

CLAIMS:

1. A valve (1), comprising: a valve body (2) delimiting a flow channel (3), a closure member (4) arranged in the valve (1) to be moved between a fully closed position preventing flow through the flow channel (3) and a fully open position allowing flow through the flow channel (3), and a metallic sealing ring (5) forming a sealing interface (6) between the closure member (4) and the valve body (2) in the fully closed position, the sealing ring (5) having a first sealing area (7) arranged to tightly contact one of the valve body (2) and the closure member (4) in the fully closed position, the sealing ring (5) having a first section (8) and a second section (9)extending from the first sealing area (7) separated from each other towards a second sealing area (10) located in a cavity (11) formed in the other one of thevalve body (2) and the closure member (4), c h a r a c t e r i z e d ^ in that amaterial thickness of at least one of the first section (8) and of the second section(9) decreases at discontinuity locations (12) in a direction from the first sealing area (7) towards the second sealing area (10).

2. The valve (1) according to claim 1, c h a r a c t e r i z e d ^ in thatthe discontinuity locations (12) are provided to corresponding locations of the first section (8) and of the second section (9).

3. The valve (1) according to claim 1 or 2, c h a r a c t e r i z e d ^ inthat at least one of the first section (8) and the second section (9) comprises asealing protrusion (15, 16) arranged to tightly contact a wall (17, 14) of the cavity(11) at the second sealing area (10).

4. The valve (1) according to any one of the claims 1 to 3,c h a r a c t e r i z e d ^ in that an outer surface (18) of the first section (8) isseparated from the first wall (17) of the cavity (11) by a gap (19) extending fromthe flow channel (3) to the first sealing protrusion (15).

5. The valve (1) according to any one of the claims 1 to 4,c h a r a c t e r i z e d ^ in that the first section (8) and the second section (9) areeach provided with at least three discontinuity locations (12) where the materialthickness decreases at corresponding locations.

6. The valve (1) according to any one of the claims 1 to 5,c h a r a c t e r i z e d ^ in that the first section (8) and the second section (9) haveinner planar surfaces (23) facing each other at the discontinuity locations (12),while the material thickness decreases at the discontinuity locations (12) due to anon-planar shape at the outer surfaces (18, 20) of the first section (8) and thesecond section (9).

7. The valve according to any one of claims 1 to 6,c h a r a c t e r i z e d ^ in that steps are provided in the outer surfaces (18, 20) ofthe first section (8) and the second section (9) at the discontinuity locations (12).

8. The valve (1) according to any one of the claims 1 to 7,c h a r a c t e r i z e d ^ in that the cavity (11) is formed in the valve body (2), andthe first sealing area (7) of the sealing ring (5) is arranged to tightly contact the closure member (4) in the fully closed position.

9. The valve (1) according to claim 8, c h a r a c t e r i z e d ^ in thatthe valve (1) comprises a clamp ring (22) connecting to the valve body (2),wherein: the valve body (2) and the clamp ring (22) together define the cavity(11) between them, andthe sealing interface (6) extends between the valve body (2) and theclamp ring (22).

10. The valve (1) according to any one of the claims 1 to 9,c h a r a c t e r i z e d ^ in that the sealing ring (5) has a generally U-shaped cross-section.

11. The valve (1) according to any one of the claims 1 to 10,c h a r a c t e r i z e d ^ in that the sealing ring (5) comprises a support protrusion(13) extending from the second section (9) towards a second wall (14) of the cavity (11) in vicinity of the first sealing area (7).

12. The valve (1) according to any one of the claims 1 to 11,c h a r a c t e r i z e d ^ in that the second wall (14) of the cavity (11) is providedwith a support protrusion (13) extending from the wall of the cavity towards the second section (9) in vicinity of the first sealing area (7).

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