GB1576020A

GB1576020A - Butterfly valve

Info

Publication number: GB1576020A
Application number: GB13882/77A
Authority: GB
Original assignee: Bestobell Valves Ltd
Current assignee: Bestobell Valves Ltd
Priority date: 1977-04-01
Filing date: 1977-04-01
Publication date: 1980-10-01
Also published as: LU79348A1; ZA781452B; DK144878A; BR7801942A; BE865494A; NL7803429A; ES468373A1; NO780919L; CA1076092A; AU3465978A; DE2813135A1; FR2385959B3; JPS53122936A; FR2385959A1; SE7803597L; IT7867713A0

Description

(54) BUTTERFLY VALVE (71) We, BESTOBELL VALVES LLMI- TED, ' a British company, of Greasbrough Road, Rotherham, South Yorkshire S60 1RE, do ' hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be' performed, to be particularly de -scribed in and by the following ,' state- ment: - The invention relates to butterfly valves of the usual kind comprising a body surrounding a substantially cylindrical tubular passageway and containing a closure flap which swings between an open position within the passageway and a closed position in which the periphery of the flap seals against the surrounding body.

A secure seal between the periphery of the closure flap and the surrounding body is sometimes provided by forming the periphery of the closure flap of resilient material, or lining the inner surface of the body with a resilient lining, or by mounting in the body a resilient seal which projects radially inwardly into the passageway.

The use of an inwardly projecting seal has the advantages that it can be shaped to make a good seal against the closure flap but the disadvantage that the projecting seal interferes with the smooth flow through the passageway when the valve is open. It has been proposed to overcome this latter disadvantage by providing a separate lining substantially flush with the radially inner part of the seal and butting against the projecting seal but this involves the use of additional parts and can interfere with the seal function.

In accordance with the present invention, a butterfly valve has a body surrounding a substantially cylindrical passageway and a closure flap which swivels within the passageway, the' body having a resilient lining which lines the body internally and defines the fluid passageway and which is provided with an integral, annular sealing portion against which the periphery of the flap engages in the - closed position, the sealing portion sprouting from the base of an annular recess in the inner surface of the lining and projecting radially inwardly to a position substantially flush with the surface defining the passageway, each axially facing side of the sealing portion being spaced from an adjacent side of the recess to provide a radially extending groove having a narrow, radially inner portion opening into the fluid passageway and a wider, radially outer portion with a cross-section bounded by a curvilinear periphery and undercutting an axially projecting lip of the sealing portion.

With this construction the sealing portion does not project significantly into the passageway, although in practice the annular tips of the lips may project slightly into the passageway. However, when the closure flap is in a closed position, a good seal is made against the flap as the fluid pressure on the high pressure side of the flap acts under the lip and urges it towards the closure flap.

The radially innermost surface of the sealing portion between the axial extremities of the sealing lips may be slightly recessed so that the lips project radially inwardly as well as axially.

At each axial end the lining may have a radially outwardly projecting integral flange which is wrapped around the body to locate the lining in position.

The integral lining and sealing portion, may be made of a material such as rubber, or a resilient synthetic plastics material such as nitrile rubber, PTFE, or PCTFE.

PCTFE is preferred to PTFE for cryogenic applications as it retains its flexibility better at subambient temperatures.

One example of a butterfly valve con struted in accordance with the present invention is illustrated in the accompanying drawings, in which: Figure 1 is a side elevation as seen from the left in Figure 2; Figure 2 is, an end elevation with parts in section; Figure 3, is a sectionttaken on the line III-III in Figure 2 with the valve closed; and Figure 4 is a section corresponding to part of Figure 3 with the valve open.

The illustrated valve has an annular cylindrical metal body 4 provided on one side with a radially outwardly projecting spindle housing 5. Two webs 6 provided with bolt holes 7 extend between an annular flange 8 at the outer end of the housing 5 and the main part of the body 4.

The body 4 is lined with an annular cylindrical replaceable lining 9 made of nitrile rubber and provided at its axial ends with integral radially outwardly extending flanges 10 which are wrapped around the ends of the body 4 and seat in recesses 11 in the body end walls. Midway along its length the lining 9 is formed with an annular recess 12 from the base of which there sprouts an integral annular sealing portion 13.Each axially facing side of the sealing portion 13 is spaced from an adjacent side of the recess 12 to provide a radially extending groove having a narrow, radially inner portion opening into the fluid passageway and defined by a radially extending part of the side of the recess 12 and an adjacent radially extending part of the sealing portion 13; and a wider, radially outer portion with a cross-section bounded by a curvilinear periphery and undercutting an axially projecting lip 14 of the sealing portion 13, the curvilinear periphery being substantially part circular. As shown in Figure 4, the radially inwardly facing surfaces of the lips 14 are inclined in a shallow V-shape towards one another and are separated by a groove 15.

The valve has a circular closure flap 16 which is fixed by two screws 17 on a spindle 18 which is rotatably mounted in PFTE coated brass bearings 19 in the spindle housing 5 and in the diametrically opposite portion 20 of the body 4. The lining 9 closely surrounds the spindle where it passes through the lining to seal the spindle to the body. The spindle 18 is fixed to an operating handle 21, although it may be rotated mechanically in other applications, such that rotation of the handle 21 through 90" rotates the spindle 18 and the closure flap 16 between the fully closed position shown in Figure 3 and a fully open position.The position of the closure flap at any time is indicated by a pointer 22 which is fixed to the handle 21 and is aligned with a mark C on a plate 23 fixed to the flange 8 in the fully closed position, and with a mark 0 in the fully open position. The handle may be located in one of a number of selected positions by a wing head screw 24 which screws through a portion 25 of the handle 21 and engages in a selected one of a number of recesses in a rack portion 26 on the flange 8.

In use the flap is used as a wafer valve and the body 4 is sandwiched between adjacent conduit modules which are drawn up together by a ring of bolts which extend radially outwardly of the body 4 between the adjacent modules, two of the bolts passing through the holes 7 in the webs 6.

A seal is made between each end of the valve and the adjacent conduit module by compression of the respective flange 10 of the lining 9. During this compression some of the resilient material from which the lining is made will be forced into a pair of machined grooves 27 in the bottom of the respective recess 11 to assist in keying the lining in position. The inner cylindrical peripheral surface of the lining 9 will be aligned with the fluid passageway through the adjacent conduit modules.

Since the valve is symmetrical, it can be used equally efficiently irrespective of the direction of flow through the valve. When the valve is closed as shown in Figure 3, the edge of the flap 16 seals against both the lips 14 of the sealing portion 13, the sealing engagement being enhanced by the fluid pressure on the high pressure side acting on the undercut of a respective one of the lips 14 thereby urging the lip more firmly into engagement with the periphery of the flap 16. When the valve is opened, the sealing portion 13 adopts the configuration shown in Figure 4 in which the extreme tips of the lips 14 are substantially in alignment with the inner cylindrical peri-: pheral surface of the lining 9 so as not to provide any significant obstruction to fluid flow through the valve.

WHAT WE CLAIM IS: 1. A butterfly valve having a body surrounding a substantially cylindrical passageway and a closure flap which swivels within the passageway, the body having a resilient lining which lines the body internally and defines the fluid passageway and which is provided with an integral, annular sealing portion against which the periphery of the flap engages in the closed position, the sealing portion sprouting from the base of an annular recess in the inner surface of the lining and projecting radially inwardly to a position substantially flush with the surface defining the passageway, each axially facing side of the sealing portion being spaced from an adjacent side of the recess to provide a radially extending groove having a narrow, radially inner portion opening into the fluid passageway and a wider, radially outer portion with a cross-section bounded by a curvilinear periphery and undercutting an axially projecting lip of the sealing portion.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. III-III in Figure 2 with the valve closed; and Figure 4 is a section corresponding to part of Figure 3 with the valve open. The illustrated valve has an annular cylindrical metal body 4 provided on one side with a radially outwardly projecting spindle housing 5. Two webs 6 provided with bolt holes 7 extend between an annular flange 8 at the outer end of the housing 5 and the main part of the body 4. The body 4 is lined with an annular cylindrical replaceable lining 9 made of nitrile rubber and provided at its axial ends with integral radially outwardly extending flanges 10 which are wrapped around the ends of the body 4 and seat in recesses 11 in the body end walls. Midway along its length the lining 9 is formed with an annular recess 12 from the base of which there sprouts an integral annular sealing portion 13.Each axially facing side of the sealing portion 13 is spaced from an adjacent side of the recess 12 to provide a radially extending groove having a narrow, radially inner portion opening into the fluid passageway and defined by a radially extending part of the side of the recess 12 and an adjacent radially extending part of the sealing portion 13; and a wider, radially outer portion with a cross-section bounded by a curvilinear periphery and undercutting an axially projecting lip 14 of the sealing portion 13, the curvilinear periphery being substantially part circular. As shown in Figure 4, the radially inwardly facing surfaces of the lips 14 are inclined in a shallow V-shape towards one another and are separated by a groove 15. The valve has a circular closure flap 16 which is fixed by two screws 17 on a spindle 18 which is rotatably mounted in PFTE coated brass bearings 19 in the spindle housing 5 and in the diametrically opposite portion 20 of the body 4. The lining 9 closely surrounds the spindle where it passes through the lining to seal the spindle to the body. The spindle 18 is fixed to an operating handle 21, although it may be rotated mechanically in other applications, such that rotation of the handle 21 through 90" rotates the spindle 18 and the closure flap 16 between the fully closed position shown in Figure 3 and a fully open position.The position of the closure flap at any time is indicated by a pointer 22 which is fixed to the handle 21 and is aligned with a mark C on a plate 23 fixed to the flange 8 in the fully closed position, and with a mark 0 in the fully open position. The handle may be located in one of a number of selected positions by a wing head screw 24 which screws through a portion 25 of the handle 21 and engages in a selected one of a number of recesses in a rack portion 26 on the flange 8. In use the flap is used as a wafer valve and the body 4 is sandwiched between adjacent conduit modules which are drawn up together by a ring of bolts which extend radially outwardly of the body 4 between the adjacent modules, two of the bolts passing through the holes 7 in the webs 6. A seal is made between each end of the valve and the adjacent conduit module by compression of the respective flange 10 of the lining 9. During this compression some of the resilient material from which the lining is made will be forced into a pair of machined grooves 27 in the bottom of the respective recess 11 to assist in keying the lining in position. The inner cylindrical peripheral surface of the lining 9 will be aligned with the fluid passageway through the adjacent conduit modules. Since the valve is symmetrical, it can be used equally efficiently irrespective of the direction of flow through the valve. When the valve is closed as shown in Figure 3, the edge of the flap 16 seals against both the lips 14 of the sealing portion 13, the sealing engagement being enhanced by the fluid pressure on the high pressure side acting on the undercut of a respective one of the lips 14 thereby urging the lip more firmly into engagement with the periphery of the flap 16. When the valve is opened, the sealing portion 13 adopts the configuration shown in Figure 4 in which the extreme tips of the lips 14 are substantially in alignment with the inner cylindrical peri-: pheral surface of the lining 9 so as not to provide any significant obstruction to fluid flow through the valve. WHAT WE CLAIM IS:

1. A butterfly valve having a body surrounding a substantially cylindrical passageway and a closure flap which swivels within the passageway, the body having a resilient lining which lines the body internally and defines the fluid passageway and which is provided with an integral, annular sealing portion against which the periphery of the flap engages in the closed position, the sealing portion sprouting from the base of an annular recess in the inner surface of the lining and projecting radially inwardly to a position substantially flush with the surface defining the passageway, each axially facing side of the sealing portion being spaced from an adjacent side of the recess to provide a radially extending groove having a narrow, radially inner portion opening into the fluid passageway and a wider, radially outer portion with a cross-section bounded by a curvilinear periphery and undercutting an axially projecting lip of the sealing portion.

2. A valve according to claim 1, in

which the radially innermost surface of the sealing portion between the axial extremities of the sealing lip is slightly recessed so that the lips project radially inwardly as well as axially.

3. A valve according to claim 1 or claim 2, in which, at each axial end, the lining has a radially outwardly projecting integral flange which is wrapped around the body to locate the lining in position.

4. A valve according to any of the preceding claims, wherein the curvilinear periphery of the radially outer portion of the groove is substantially part circular.

5. A valve according to claim 4, wherein the radially inner portion of the groove is defined by a radially extending part of the side of the recess and an adjacent radially extending part of the sealing portion, the radially extending part of the side of the recess merging tangentially into the substantially part circular part of the sealing portion to define the radially outer portion of the groove.

6. A valve according to claim 1, substantially as described with reference to the accompanying drawings.