GB2352018A - Butterfly valve - Google Patents

Abstract

A butterfly valve 5 comprising an annular valve seat 10 having a sealing surface and a non-circular valve disc 120 rotatable within the valve seat and co-operable with the sealing surface to selectively open and close the valve. The valve disc 120 may be elliptical and have the axis of rotation coincident with the major axis of the ellipse. This arrangement is intended to reduce the torque required to actuate the valve 5.

Description

2352018 IMPROVEMENTS IN BUTTERFLY VALVES This invention relates to

improvements in bufterfly 5 valves, and, in particular, wafer-type butterfly valves.

Wafer-type butterfly valves are well known in the art, such as GB 2,206, 672 to the present applicant. However, this design requires a substantial amount of torque to facilitate operation of the valve. Consequently, a large actuator needs to be included as an integral part of this system in order to supply the necessary level of torque required.

The size of this actuator, combined with the physical size of the valve, therefore increases the overall size of the valve system to the point where it can become cumbersome. Consequently, the entire system is difficult to install, for example within a pipeline, difficult to maintain, and presents difficulties for replacing worn parts.

Such systems also require frequent maintenance to keep the actuator and valve functional due to the loads placed upon them by their size and the wear and tear resulting from operation.

The present invention is concerned with providing a butterfly valve in which at least some of the above mentioned problems are overcome or at least alleviated.

According to one aspect of the present invention there is provided a valve comprising an annular valve seat having 2 a sealing surface and a non-circular valve disc rotatable within the valve seat and co-operable with the sealing surface to selectively open and close the valve.

Advantageously the valve disc may be elliptical.

In accordance with another aspect of the present invention there is provided an apparatus comprising a ringshaped valve seat made from a resilient material, wherein said valve seat has a radially extending flanged outer face at either end, the underside of each said face being contiguous with a diameter which forms part of an annular section containing an annular groove, both of said annular grooves being equally disposed about, and located around, either side of a vertically extending shaft aligned with the central axis of said valve seat, said shaft being connected to an elliptical disc located within the bore of said valve seat. By combining the elliptical disc with the valve seat in this manner produces the advantageous result of reducing the torque required to operate the valve without affecting the pressure holding of the valve. Furthermore, the size of the actuator controlling the valve can be decreased thereby reducing the cost and size of the overall system.

The diametral difference between the disc height and disc width of the elliptical disc may vary from lmm to 2.5mm depending on the desired pressure/torque ratio.

The bore of said valve seat has two diametrically opposite bores formed thereupon into which said elliptical disc may be located. Additionally, said bores may be aligned generally with the axis of said shaft.

3 Furthermore, the elliptical disc has location means which may be suitably configured for locating within said diametrically opposite bores. In addition, these diametrically opposite bores for locating the elliptical disc stem may be confined within the axial extent of the annular sections.

Each annular groove may be arranged contiguously with an annular ring which comprises an annular flange and an annular spigot. As a result, said annular flange may be located within said annular groove so that the underside of said flanged outer face is in sealed contact with a surface of said annular ring.

The annular flange may extend in a direction generally parallel to the horizontal axis of the valve seat bore and may be generally perpendicular to the vertical axis of the diametrically opposite bores.

Each annular ring may have the capability of being secured together using fastening means. This has the added advantage of forcing the annular flanges to locate within each annular groove in such a manner as to tightly secure the assembly of annular flanges and grooves together thus forming a seal.

The annular rings may also be equally disposed around either side of said vertically extending shaft so that the bore dimension formed by the annular spigots in these two annular rings to locate said shaft is identical to, and in alignment with, the bore dimension formed in the section of the valve seat having the annular grooves. Both of these bores may be aligned along the same central axis of the shaft.

4 The housing containing the valve seat and the elliptical disc may be connected to a flanged tubular adaptor. The shaft which is connected to the elliptical disc may extend through a bore in this adaptor and may have a squared end. This squared end may be turned manually or by means of an actuator.

Brief Description of the Drawings

An embodiment of the present invention will now be described by way of example only, with reference to the following drawings, in which; Fig 1 shows an axial section made in accordance with the present invention; Fig 2 shows an end elevation of the butterfly valve made in accordance with the present invention; and Fig 3 shows an enlarged partial section of the present invention as shown in Fig 1.

Specific Description of the Preferred Embodiment

Figure 1 of the accompanying drawings shows a wafer type butterfly valve 5. Typically, the wafer-type butterfly valve 5 comprises a valve seat 10 which is ring-shaped and made of a resilient material suited to the application of the valve 5. At each end of the valve 10 there is a radially extending flanged outer face 20 having an outside diameter 125. As shown in Figure 3 of the accompanying drawings, the underside of this face 25 is contiguous with a stem diameter 45 which extends along the annular section 30 to form one diameter 55 of an annular groove 35, otherwise known as the internal groove diameter. The other diameter 65, known as the groove outside diameter, of the annular groove 35 forms the inner wall of an annular rim 75 having an outer diameter 85. Both diameters 65, 85, extend in a direction generally parallel to the stem diameter 45 and the valve seat bore. Generally perpendicular to these diameters 65, 85 are diametrically opposite bores 60 which are formed in the valve seat bore. These bores 60 extend only as far as the axial extent of the annular sections 30.

The annular sections 30 are retained within a housing 90 comprising two annular rings 100 and 110, both of which are identical to each other. Each annular ring 100, 110 has an annular flange 115 which is dimensioned in such a manner as to locate within the annular groove 35 of each annular section 30. Both rings 100, 110 have an annular spigot 95 which, when assembled together, forms a bore 170.

The rings 100 and 110 are also equally disposed around the axis of the vertically extending shaft 130. In this way, the bore 170 formed by the annular spigots 95 is equal to the bore dimension 60 formed by the annular sections 30.

When assembled together, the outer flange diameter 125 and the underside flange face 25 of the annular section 30 are supported within a location bore 135. Fastening means 260 are provided which, when secured, forces the annular flange 115 to locate within the annular groove 35 in such a manner as to from a seal. It also enables the outer flange face to function as a gasket between the surface of the housing and any fittings attached thereto such as pipeline flanges.

6 An elliptical butterfly valve member 120 has a shaft and trunnion 140 diametrically opposite the shaft 130.

The trunnion 140 extends through one of the diametrically opposite bores 60 and into a blind hole 150 formed in the two annular rings 100 and 110. The dimensional difference between the disc height and the disc width varies depending on the desired pressure/torque ratio. The diametral difference of the elliptical disc will vary from 1mm to 2.5mm, with the disc height diameter measured at the hub being greater than the width diameter measured at 90 degrees to the hub. The hub is the area created by the shafts joining the disc.

A bearing bush 160 is provided in the blind hole 150.

The shaft 130 extends through the other diametrically opposite bore 60 and a bore 170 formed by the annular spigot 9S in the two annular rings 100 and 110. A flanged tubular adaptor 180 is secured to the housing 90 and the shaft 130 extends through a bore 190 in the adaptor 180 and projects therefrom with a squared end 200 for turning either manually or by means of an actuator. Bearing bushes are provided at 210 and 220 and an 0ring at 230. Thickenings 240 are provided on the elliptical 25 disc 120 where the shaft 130 and trunnion 140 extend from the disc 120. The thickenings 240 prevent annular flat surfaces 250 engaging the surfaces -70. By combining the elliptical disc 120 with the valve seat 10 in this mariner, the torque required to operate the valve without affecting the pressure holding of the valve is reduced. Additionally, the size of the actuator (not shown, but connected to the squared end 200 of the shaft 130) controlling the valve can be decreased thereby reducing the 7 cost and size of the overall system. By reducing the size of the actuator, the amount of maintenance is reduced as is the wear and tear on the component parts of the actuator. By reducing the size of the overall system, a wider variety and range of applications can be addressed. Further-more, the scope and range of sites for installation is now greater and more widely available whereas before this was limited due to the system's size.

The valve and the disc can be made in a wide range of sizes and with a seat 10 made of a resilient material to suit its application.

Whilst the present invention has been described with particular reference to a valve seat as shown in GB 2,206,672, it is to be understood that the form of the valve seat of the present invention is not intended to be limited to such a configuration.

8

Claims (1)

1. A valve comprising an annular valve seat having a sealing surface and a non-circular valve disc rotatable within the valve seat and co-operable with the sealing surface to selectively open and close the valve.

2. A valve according to claim 1, wherein the valve disc is elliptical.

3. An apparatus comprising a ring-shaped valve seat made from a resilient material, wherein said valve seat has a radially extending flanged outer face at either end, the underside of each said face being contiguous with a diameter which forms part of an annular section containing an annular groove, both of said annular grooves being equally disposed about, and located around, either side of a vertically extending shaft aligned with the central axis of said valve seat, said shaft being connected to an elliptical disc located within the bore of said valve seat.

4. A valve according to any one of the preceding claims, wherein the diametral difference between the disc height and disc width of the elliptical disc varies from lmm to 2.5mm depending on the desired pressure/torque ratio.

S. A valve according to claim 3, wherein the bore of said valve seat has two diametrically opposite bores formed thereupon into which said elliptical disc may be located.

9 6. A valve according to claim 3 or 5, wherein said bores are aligned generally with the axis of said shaft.

7. A valve according to any one of claims 3, 5 or 6, wherein the elliptical disc has location means which are suitably configured for locating within said diametrically opposite bores.

8. A valve according to claim 5, wherein the diametrically opposite bores for locating the elliptical disc stem are confined within the axial extent of the annular sections.

9. A valve according to any one of claims 3 or 5 to 8, wherein each annular groove is arranged contiguously with an annular ring which comprises an annular flange and an annular spigot.

10. A valve according to claim 9, wherein said annular flange is located within said annular groove so that the underside of said flanged outer face is in sealed contact with a surface of said annular ring.

11. A valve according to claim 9 or 10, wherein the annular flange extends in a direction generally parallel to the horizontal axis of the valve seat bore and is generally perpendicular to the vertical axis of the diametrically opposite bores.

12. A valve according to any one of claims 3 or 5 to 11, wherein each annular ring has the capability of being secured together using fastening means.

13. A valve according to any one of claims 3 or 5 to 12, wherein the annular rings are equally disposed around either side of said vertically extending shaft so that the bore dimension formed by the annular spigots in these two annular rings to locate said shaft is identical to, and in alignment with, the bore dimension formed in the section of the valve seat having the annular grooves.

14. A valve substantially as herein before described with 10 reference to and as shown in the accompany drawings.