GB2079406A

GB2079406A - Fluid flow check valve

Info

Publication number: GB2079406A
Application number: GB8038124A
Authority: GB
Original assignee: KIM VALVES Ltd
Current assignee: KIM VALVES Ltd
Priority date: 1980-07-01
Filing date: 1980-11-27
Publication date: 1982-01-20

Abstract

A fluid flow check valve comprising a body (202) housing a valve seat (212) and a valve member (206) in the form of a disc mounted to swing relative to the valve body about a hinge axis, the valve member including a hinge pin (206a) formed integrally with the disc, the disc having a sealing surface (206b) engageable with the valve seat, the sealing surface having a region merging into the hinge pin which, when the disc is viewed from the front, has its longitudinal axis X extending generally tangentially to the outer periphery of the sealing surface. The disc and seat may be formed as a removable unit. <IMAGE>

Description

SPECIFICATION Fluid flow check valve This invention relates to fluid flow check valves of the swing type incorporating a valve member in the form of a disc which swings about a hinge relative to a valve body.

According to the present invention, there is provided a fluid flow check valve comprising a body defining a valve seat, and a valve member in the form of a disc mounted to swing relative to the valve body about a hinge axis, the valve member including a hinge pin formed integrally with the disc, the disc having an annular sealing surface engageable with the valve seat, the sealing surface having a region merging into the hinge pin which, when the disc is viewed from the front, has its longitudinal axis extending generally tangentially to the outer periphery of the sealing surface.

Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure l is a cross-section through an embodiment of check valve according to the invention, Figure 2 is a front view of a support plate of the valve of Figure 1, Figure 3 is a cross-section of a further embodiment of checkvalve according to the invention, Figure 4 is a section on the line A-A in Figure 3, and Figure 5 is a scrap section of Figure 3 with the addition of a return spring acting on the valve member.

Referring to Figure 1 and 2, the check valve 100 comprises a one part metal valve body 102 defining a flat valve seat 104 which cooperates with a metal valve closure member 106 of disc form. The disc 106 has an integral hinge pin 106a and a machined or lapped annular sealing surface 106b having its upper region 106c merging into the hinge pin which as seen from the front view of Figure 2 has its longitudinal axis X extending generally tangentially to the outer periphery of sealing surface 106b.

The disc on its upstream side 106dis recessed and on its downward side is provided with a counterweight portion 106e, both features being employed to ensure that the disc will remain under the influence of gravity in engagement with its valve seat even though the valve may be mounted a few degrees off a true horizontal position.

To support and pivot the disc, a shaped (pressed metal) support plate 108 is inserted from the downstream end of the valve body toward the valve seat where its upper end is located by a lug 110 integrally formed in the valve body; the lower end having a hole 112 to enable the plate to be secured to the body by means of screw 114.

The plate 108 is provided with part-cylindrical portions 1 08a which together with the valve seat 104 surround the disc hinge pin to provide a pivot recess therefor.

An elastomeric sealing ring 116 is provided in the valve seat which since it faces downstream is not directly impinged upon by the fluid passing through the valve.

In the embodiment of Figure 3, the valve body 202 is in three parts comprising end caps 202a and intermediate part 202b; the valve disc 206 is similar in construction to valve disc 106 of the previously described embodiment, with the annular sealing surface 206b merging at its upper region into the hinge pin which as seen in Figure 4 has its longitudinal axis X extending generally tangentially to the outer periphery of sealing surface 206b.

However, in the embodiment of Figure 3, the disc forms part of a disc/valve seat sub-assembly 210 which can be inserted or removed from valve body 206 as a unitary item.

Sub-assembly 210 includes an annular support 212 provided with a through bore 214to permit passage of fluid through the valve and a flat valve seat 21 2a surrounding bore 214 and facing downstream of the valve body. The valve disc is located in an annular recess 212b of the support, and the hinge pin 206a of the disc is located in an open-ended rectilinear slot 21 2c which extends at a tangent to recess 21 2b. The relative dimensions of the hinge pin and rectilinear slot are such that the hinge pin is loosely located in the slot and the extremities of the pin just extend to the outer periphery of support 212 as seen more clearly in Figure 4.

The hinge pin of the valve disc is retained in slot 21 2c by means of a flat ring 216 which is secured to support 212 buy a headed pin 218 having a plain shank portion 21 8a passing through a hole in ring 216 and push fitted into a hole 21 2d in the support When assembled in valve body 202, the subassembly 210 is clamped between end cap 202a and intermediate part 202b of the valve body, and the ends of the hinge pin 206a just abut a radially inwardly facing surface 202c of the intermediate part 202b of the valve body to ensure an accurate lateral location for the valve disc.

Elastomeric seals 220 and 222 are provided respectively in the valve seat 212a and in the interface between support 212 and intermediate part 202b.

In the event of fire, it is possible that these seals will melt; therefore provision is made to ensure that the sub-assembly is still functional. In this respect the downstream facing surface area of support 212 between seal 220 and bore 214 is reduced in thickness to a continuous thin line extending around bore 214 and which in the event of seal 220 disintegrating will sealingly contact the sealing face of the valve disc. In addition, end cap 202a is provided with a pointed lip 224 surrounding bore 214 and which in the event of seal 222 disintegrating will sealingly contact a chamfered surface 212e of the support.

In a modification (Figure 5), a closure spring 230 is added to the valve disc 206 to assist gravity in closing the valve. The spring is preferably formed in one piece and includes two helical coiled portions 230a located one each side of headed pin 218, with their longitudinal axes parallel to the hinge axis of the disc, an end coil of each portion being offset so as to surround the shank of pin 218 and be clamped between the head of the pin and ring 216, the outer ends of the portions being connected to a vertically extending portion 230b of the spring which engages a downstream facing verticaliy extending ridge 206c of the valve disc to bias it toward its valve seat. The disc 106,206 is cast by the investment casting process which conveniently allows the upper region of the valve seat to extend upwardly as far as the horizontal axis X of the hinge pin (see Figures 2 and 3), thereby enabling the valve disc to be extremely compact which is particularly advantageous in small sizes of check valve. Ridge 206c extends toward and merges with laterally extending counterweight portion 206d.

Other materials such as metals may replace, or may be incorporated with, the elastomeric material of the above described seals and sealing rings.

Claims

1. A fluid flow check valve comprising a body defining a valve seat, and a valve member in the form of a disc mounted to swing relative to the valve body about a hinge axis, the valve member including a hinge pin formed integrally with the disc, the disc having an annular sealing surface engageable with the valve seat, the sealing surface having a region merging into the hinge pin which, when the disc is viewed from the front, has its longitudinal axis extending generally tangentially to the outer periphery of the sealing surface.

2. The check valve of Claim 1, wherein the disc and valve seat together form a sub-assembly which can be inserted and removed from the valve body as a unitary item.

3. The check valve of Claim 2, wherein the sub-assembly includes an annular support provided with a through bore and defining a valve seat facing downstream of the valve body, the valve disc being located in an annular recess provided in the support and the hinge pin being located in an open-ended rectilinear slot extending at a tangent to the annular recess.

4. The check valve of Claim 3, wherein the relative dimensions of the hinge pin and slot are such that the hinge pin is loosely located in the slot and the extremities of the pin just protrude beyond the outer periphery of the support.

5. The check valve of Claim 3 or 4, wherein the hinge pin is retained in the slot by a flat ring secured to the support.

6. A check valve of Claim 5, wherein the flat ring is secured by a headed pin having a shank portion passing through a hole in the ring and fitted into a hole in the support.

7. The check valve of Claim 4 or Claim 5 or 6 as appendant to Claim 4, wherein the protruding ends of the hinge pin abut a radially inwardly facing surface of the valve body thereby to laterally locate the valve disc relative to the valve body.

8. The check valve of any one of the preceding Claims, wherein the disc has an annular sealing surface engageable with the valve seat, the sealing surface having a region merging into the hinge pin which, when the disc is viewed from the front has Its longitudinal axis extending generally tangentially to the outer periphery of the sealing surface.

8. The check valve of Claim 6 or Claim 7 as appendantto Claim 6, wherein a return spring is provided to assist closure of the valve disc, the spring being of one piece and including two helical coiled portions located one each side of headed pin with their longitudinal axes parallel to the hinge axis of the disc, an end coil of each coil portion being offset so as to surround the pin shank and be clamped between the head of the pin and the ring.

9. The check valve of any one of the preceding claims, wherein the valve member is formed by the investment casting process.

New claims or amendments to claims filed on 30 July 1981 Superseded claims 1-9 New or amended claims:

1. Afluid flow checkvalve comprising a valve body, a sub-assembly, including a valve member and annular valve member support, located within the valve body and removable therefrom as a unitary item, the valve member being in the form of a disc mounted to swing relative to the annular support about a hinge axis, the valve member including a hinge pin of round cross-section, the annular support defining a through bore and a valve seat engageable with the disc, the hinge pin being located in an open-ended rectilinear slot extending laterally of the through bore and provided in the annular support, the ends of the hinge pin abutting a radially inwardly facing surface of the valve body thereby to laterally locate the valve disc relative to the valve body.

2. The check valve of Claim 1, wherein the valve disc is located in an annular recess provided in the support and the rectilinear slot extends at a tangent to the annular recess.

3. The check valve of Claim 1 or 2, wherein the relative dimensions of the hinge pin and slot are such that the hinge pin is loosely located in the slot.

4. The check valve of Claim 1,2 or 3, wherein the hinge pin is retained in the slot by a flat hinge secured to the support.

5. The check valve of Claim 4, wherein the flat ring is secured by a headed pin having a shank portion passing through a hole in the ring and fitted into a hole in the support.

6. The check valve of Claim 5 as appendant to Claim 4, wherein a return spring is provided to assist closure of the valve disc, the spring being of one piece and including two helical coiled portions located one each side of the headed pin with their longitudinal axes parallel to the hinge axis of the disc, and end coil of each coil portion being offset so as to surround the pin shank and be clamped between the head of the pin and the hinge.

7. The check valve of any one of the preceding Claims, wherein the valve member is formed by the investment casting process.