CHECK VALVE

Abstract

A check valve comprising a valve body having a central bore a hinge pin a blocking means pivotably attached to the hinge pin and moveable between a first position in which the blocking means blocks the central bore and a second position in which the blocking means does not block the central bore, and a biasing means arranged to bias the blocking means into the first position, wherein the valve body comprises at least one boss projecting from an inner wall of the valve body into the central bore, and wherein said boss provides an anchoring point at which the hinge pin is secured to the valve body.

Claims

1. A check valve comprising: a valve body having a central bore; a hinge pin; a blocking means pivotably attached to the hinge pin and moveable between a first position in which the blocking means blocks the central bore and a second position in which the blocking means does not block the central bore; and a biasing means arranged to bias the blocking means into the first position, wherein the valve body comprises at least one boss projecting from an inner wall of the valve body into the central bore, and wherein said boss provides an anchoring point at which the hinge pin is secured to the valve body.

2. A check valve according to claim 1, wherein the valve body comprises a pair of bosses located at diametrically opposed positions on the inner wall of the valve body, each boss providing anchoring points at which a respective end of the hinge pin is secured to the valve body.

3. A check valve according to claim 1, wherein the valve body comprises a horizontal slot extending along the central bore, along which the hinge pin may be inserted into the valve body.

4. A check valve according to claim 1, wherein the, or each, anchoring point comprises a through-hole extending through the, or each, boss, through which a retaining means may be passed to secure the hinge pin to the valve body.

5. A check valve according to claim 4, wherein the retaining means comprises a locking pin.

6. A check valve according to claim 1, wherein the blocking means comprises a pair of semi-circular plate members attached to the hinge pin.

7. A check valve according to claim 6, further comprising a stop pin positioned within the central bore to prevent the pair of semi-circular plate members from contacting one another.

8. A check valve according to claim 7, wherein the stop pin is secured to the valve body at the, or each, anchoring point.

9. A check valve according to claim 1, wherein the biasing means comprises a coil spring.

10. A method of assembling a check valve, the method comprising the steps of: providing a valve body having a central bore, wherein the valve body comprises at least one boss projecting from an inner wall of the valve body into the central bore, said boss comprising an anchoring point; providing a sub-assembly comprising a hinge pin, a blocking means pivotably attached to the hinge pin and moveable between a first position and a second position, and a biasing means arranged to bias the blocking means into the first position; inserting the sub-assembly into the valve body; rotating the sub-assembly until the hinge pin contacts the anchoring point; and securing the hinge pin to the anchoring point, wherein, following insertion of the sub-assembly into the valve body, the blocking means blocks the central bore in its first position and does not block the central bore in its second position.

11. A method according to claim 10, wherein the valve body comprises a pair of bosses located at diametrically opposed positions on the inner wall of the valve body, each boss providing anchoring points at which a respective end of the hinge pin may be secured to the valve body.

12. A method according to claim 10, wherein the valve body comprises a horizontal slot extending along the central bore, along which the hinge pin may be inserted into the valve body during the step of inserting the sub-assembly into the valve body.

13. A method according to claim 10, wherein the, or each, anchoring point comprises a through-hole extending through the, or each, boss, through which a retaining means may be passed to secure the hinge pin to the valve body.

14. A method according to claim 13, wherein the retaining means comprises a locking pin.

15. A method according to claim 10, wherein the blocking means comprises a pair of semi-circular plate members attached to the hinge pin.

16. A method according to claim 15, further comprising the step of positioning a stop pin within the central bore to prevent the pair of semi-circular plate members from contacting one another.

17. A method according to claim 16, wherein the stop pin is secured to the valve body at the, or each, anchoring point.

18. A method according to claim 10, wherein the biasing means comprises a coil spring.

19. A kit of parts for assembly into a check valve, the kit of parts comprising: a valve body having a central bore, wherein the valve body comprises at least one boss projecting from an inner wall of the valve body into the central bore, said boss comprising an anchoring point; a sub-assembly for insertion into the valve body, the sub-assembly comprising: a hinge pin; a blocking means pivotably attached to the hinge pin and moveable between a first position and a second position; and a biasing means arranged to bias the blocking means into the first position, wherein, following insertion of the sub-assembly into the valve body, the blocking means blocks the central bore in its first position and does not block the central bore in its second position; and means to secure the hinge pin to the valve body at the anchoring point.

20. A kit of parts according to claim 19, wherein the valve body comprises a pair of bosses located at diametrically opposed positions on the inner wall of the valve body, each boss providing anchoring points at which a respective end of the hinge pin is secured to the valve body.

21. A kit of parts according to claim 19, wherein the valve body comprises a horizontal slot extending along the central bore, along which the hinge pin may be inserted into the valve body.

22. A kit of parts according to claim 19, wherein the, or each, anchoring point comprises a through-hole extending through the, or each, boss, through which a retaining means may be passed to secure the hinge pin to the valve body.

23. A kit of parts according to claim 22, wherein the retaining means comprises a locking pin.

24. A kit of parts according to claim 19, wherein the blocking means comprises a pair of semi-circular plate members attached to the hinge pin.

25. A kit of parts according to claim 24, further comprising a stop pin positioned within the central bore to prevent the pair of semi-circular plate members from contacting one another.

26. A kit of parts according to claim 25, wherein the stop pin is secured to the valve body at the, or each, anchoring point.

27. A kit of parts according to claim 19, wherein the biasing means comprises a coil spring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The invention will now be described with reference to the accompanying drawings, in which:

[0042] FIG. 1 shows a dual plate check valve;

[0043] FIG. 2 shows a cross-sectional view of a valve body suitable for use in the present invention;

[0044] FIG. 3 shows a perspective view of the valve body of FIG. 2;

[0045] FIGS. 4-7 schematically show perspective views of an apparatus in accordance with an embodiment of the present invention at various stages of assembly; and

[0046] FIGS. 8a, 8b and 8c respectively show perspective, cross-sectional and cutaway views of the apparatus of FIGS. 4-7 fully assembled.

DETAILED DESCRIPTION

[0047] FIG. 2 shows a cross-sectional view of a valve body 10 suitable for use in the present invention. The valve body 10 has an internal bore through which fluid may flow when the valve body 10 is connected to a pipeline. In the prior art, the internal bores of valve bodies are generally circular, and may include cutaways for receiving inserts (see, for example, the valve body shown in FIG. 1). However, in the present invention, the internal bore of the valve body 10 includes a pair of diametrically opposed bosses B which project into the internal bore.

[0048] Compared to prior art check valves, the diameter of the internal bore has been increased to allow room for the bosses B on the walls of the valve body 10. The bosses B are integrally formed with the valve body 10.

[0049] As can be seen in FIG. 3, the bosses B have a pair of vertical slots S cut into them, spaced along the valve body 10. The bosses B also have a horizontal slot L cut into them, which extends along the valve body 10 as shown. Only one horizontal slot L can be seen in FIG. 3, however the boss on the opposite side has an equivalent horizontal slot, diametrically opposed to the horizontal slot L visible in FIG. 3. Both slots are formed by milling during the manufacturing process. The bosses B have respective through-holes 11a and 11b drilled into them.

[0050] FIG. 4 schematically shows a perspective view of an apparatus in accordance with an embodiment of the present invention prior to assembly. The valve body 10 is the same as that shown in FIG. 3.

[0051] The apparatus comprises a hinge pin and plate sub-assembly 15. The assembly 15 comprises a pair of semi-circular plates 16a, 16b arranged for pivoting movement about a hinge pin 17. The hinge pin 17 has a first aperture 18a at a first end, and a second aperture 18b at a second end. A coil spring 19 surrounds the hinge pin 17 and acts to bias the semi-circular plates 16a, 16b into their respective closed positions.

[0052] The apparatus further comprises stop pin 20. Similarly to the hinge pin 17, the stop pin 20 has a first aperture 21a at a first end, and a second aperture 21b at a second end.

[0053] Finally, the apparatus further comprises a pair of locking pins 22a, 22b and a pair of associated grub screws 23a, 23b.

[0054] FIG. 5 schematically shows a perspective view of the apparatus of FIG. 4 at a first stage of assembly.

[0055] The sub-assembly 15 has been inserted into the interior of the valve body 10. This is achieved by aligning the hinge pin 17 with the horizontal slots L. These slots provide enough clearance for the hinge pin 17 to be inserted perpendicular to the inner wall of the valve body 10. The diameter of the interior bore of the valve body is less than the length of hinge pin 17 at every other point on the inner wall, and so the sub-assembly can only be inserted at a predetermined angle (although it may also be inserted 180 to this angle).

[0056] The sub-assembly 15 is progressively inserted in the valve body 10 until the hinge pin 17 contacts a portion of the inner wall of the valve body 10 at the point shown in FIG. 5. At this point, the hinge pin has reached the end of horizontal slot L, and abuts a portion of the inner wall of the valve body 10, preventing further insertion. This aids assembly of the dual check valve, as an installer need not check to see how far the sub-assembly 15 has been inserted into the valve body 10. Instead, an installer can simply insert the sub-assembly 15 to its furthest extent, at which point he will know that the hinge pin 17 is aligned with the appropriate slot of the bosses B.

[0057] FIG. 6 schematically shows a perspective view of the apparatus of FIG. 4 at a further stage of assembly.

[0058] In FIG. 6, the sub-assembly 15 has been rotated in a clockwise direction relative to the direction of insertion until the first and second apertures 18a, 18b of the hinge pin 17 are aligned with the through-holes 11a, 11b. The stop pin 20 has been inserted into the valve body 10 in a similar way to the hinge pin 17 until it is aligned with an appropriate slot of the bosses B.

[0059] FIG. 7 schematically shows a perspective view of the apparatus of FIG. 4 at a yet further stage of assembly.

[0060] The stop pin 20 has been rotated in a clockwise direction relative to the direction of insertion until its first and second apertures 21a, 21b are aligned with the through-holes 11a, 11b.

[0061] The locking pins 22a, 22b are shown being inserted into through-holes 11a, 11b.

[0062] FIG. 8a shows a perspective view of the apparatus of FIG. 4 fully assembled. The locking pins 22a, 22b have been fully inserted into through-holes 11a, 11b, and the grub screws 23a, 23b have been inserted into through-holes 11a, 11b, and rotated to hold the locking pins 22a, 22b in place. In this fully assembled state, the locking pins 22a, 22b pass through the through-holes 11a, 11b, the first and second apertures 21a, 21b of the stop pin 20 and the first and second apertures 18a, 18b of the hinge pin 17. The locking pins 22a, 22b act to hold the stop pin 20 and the hinge pin 17 in their respective positions and prevent their movement.

[0063] The semi-circular plates 16a, 16b may rotate around the hinge pin 17 when the force provided by fluid flow in the valve body exceeds the combined force provided by the spring 19 and the pressure differential across the semi-circular plates 16a, 16b. The extent of the rotation of the semi-circular plates 16a, 16b is limited by the stop pin 20, which prevents the semi-circular plates 16a, 16b from fluttering due to vortex shedding. This acts to reduce wear and pressure loss.

[0064] FIG. 8b shows a cross-sectional view of the apparatus of FIG. 4 fully assembled.

[0065] In this view it is possible to see a runout groove 30. This is provided where both the semi-circular plates 16a, 16b and the valve body 10 form a metal to metal seal, to prevent a raised edge forming on the body seal surface during lapping, which could hold the plate off the seal surface and prevent an effective seal being formed when the semi-circular plates 16a, 16b are in their closed position. However, the runout groove 30 can be omitted in other circumstances, e.g. where a resilient rubber seal is bonded into the valve body 10.

[0066] FIG. 8c shows a cutaway view of the apparatus of FIG. 4 fully assembled. The cutaway runs along the longitudinal axes of the stop pin 20 and the hinge pin 17. It can be seen that the locking pins 22a, 22b pass through the through-holes 11a, 11b, the first and second apertures 21a, 21b of the stop pin 20 and the first and second apertures 18a, 18b of the hinge pin 17 to hold the stop pin 20 and the hinge pin 17 in their respective positions and prevent their movement.

[0067] When the valve body 10 is attached to a pipeline, the grub screws 23a, 23b are covered by the pipeline. This prevents disassembly of the check valve during use, and also acts as an anti-tamper device.

[0068] Alternative Arrangements

[0069] The invention is not limited to the specific embodiments disclosed above, and other possibilities will be apparent to those skilled in the art. For example, while the Figures show a dual plate check valve in which the blocking means is a pair of semi-circular plates, other suitable blocking means could also be used. For example, a single plate.

[0070] While the horizontal slots L have been described as being formed by milling in the example above, these slots could also be turned, or they could be formed using an investment casting process. While the through-holes 11a, 11 b have been described as being drilled into the bosses B in the example above, they could also by formed by broaching, water jet or plasma cutter. While the specific embodiment of the Figures discloses a pair of diametrically opposed horizontal slots L, the invention would also work with only a single horizontal slot.