WO1999035426A1

WO1999035426A1 - An interception and regulation valve for fluids, with a butterfly shutter

Info

Publication number: WO1999035426A1
Application number: PCT/EP1999/000064
Authority: WO
Inventors: Paolo Masso
Original assignee: RIZZIO VALVOLE SpA
Current assignee: RIZZIO VALVOLE SpA
Priority date: 1998-01-12
Filing date: 1999-01-08
Publication date: 1999-07-15
Anticipated expiration: 2000-07-12
Also published as: ITTO980018A1; AU2716099A

Abstract

The valve comprises a body constituted by two pieces (10a) of rigid synthetic material. The two pieces (10a) have an at least substantially specular shape with respect to one another and mate along a median plane containing the axis of an operating shaft (20) on which is fitted a disc-like butterfly shutter (18). The two pieces (10a) have respective annular parts (12a) which define the lumen for passage of fluid in the valve, in which the shutter (18) is located. In the lumen there is fitted an annular metal insert (24) diametrally traversed by the operating shaft (20). The annular insert (24) is lined, preferably by vulcanisation, a seal (26) of elastomer which comprises a layer (46) which clads an inner cylindrical surface of the insert (24) and is sealingly engagable by the periphery of the shutter (18).

Description

An interception and regulation valve for fluids, with a butterfly shutter

The present invention relates to an interception and regulation valve for fluids according to the preamble of Claim 1.

Known valves of the type considered are widely used for controlling the flow of liquids, and also gases, with relatively large flow rates and also at relatively high pressures.

The body of such known valves is constituted by a single cast or forged piece which, in dependence on the application, may be cast iron, high quality or stainless steel, or even aluminium.

These metal valve bodies, as well as being relatively heavy in the case of cast iron and steel, are expensive to produce. In fact, forged or cast workpieces must be finished with mechanical working operations such as turning and/or broaching and grinding of their cylindrical surfaces. These operations are relatively complex.

The object of the present invention is that of producing a valve of the type considered which, for the same dimensions, comprises a very much lighter body which is very much less expensive to produce, and which nevertheless has a mechanical strength equivalent to that of known valves of the same category, in particular in respect of the internal pressures.

According to the present invention this object is achieved by means of a valve as claimed. In a valve according to the invention the body comprising two mating pieces, being of synthetic material, is lighter and more economical than a one-piece metal body. Certain cylindrical surfaces, such as those of the lumen of the annular part, which in a metal body require mechanical working, can be obtained directly in a finished piece by moulding with the necessary precision.

The two-piece body of synthetic material would not in itself be adapted to resist the relatively high internal pressures. In the valve according to the invention the mechanical strength to resist internal pressures is however achieved by the annular metal insert. This insert, having the simple form of a body of revolution, lends itself economically to production with correspondingly simple turning operations starting from a rough annular piece which can be a piece of a tubular blank or a cast or forged piece.

Further characteristics and advantages of the invention will become apparent from reading the detailed description which follows, which is given with reference to the attached drawings which illustrate a preferred embodiment thereof, and in which:

Figure 1 is a front elevation of the valve with its shutter in a partly open position;

Figure 2 is a transverse section taken on the line II-II of Figure 2, with the shutter in a closed position;

Figure 3, subdivided into Figures 3a and 3b, is an exploded perspective view of the same valve; and

Figure 4 is a perspective view of one of the two pieces of which the body of the valve is composed, seen from its face which in the assembled condition is directed towards the other part of the body. Referring to Figures 1 and 2, an interception and regulation valve according to the invention comprises a body generally indicated 10.

As in known valves of the same type, the body 10 comprises an annular part 12 and a tubular projection 14 which extends radially from the annular part 12.

The annular part 12 defines a cylindrical lumen 16 for the passage of the fluid to be controlled.

A disc-like shutter 18 of the butterfly type is rotatably mounted in the lumen 16, which butterfly can be of metal or synthetic material.

Through the lumen 16 and within the projection 14 of the body 10 extends a rotatable control shaft 20 to which the shutter 18 is fixed for rotation.

At the end of the projection 14 remote from the annular part 12 the shaft 20 has a square projecting tang 22 for coupling to a manipulation member such as a handwheel or an actuator of known type, for example, electrical, hydraulic or pneumatic.

Within the lumen 16 of the annular part 12 there is fitted an annular metal insert generally indicated 24 and better seen in Figure 3.

As will be made clearer hereinbelow, the insert 24 is provided with a seal 26 with which the butterfly shutter 18 cooperates peripherally.

The preferred characteristics of the insert 24 and of its seal 26 will be described hereinbelow. The annular part 12 of the body 10 is intended to be clamped between two counterposed flanges of a conduit (not shown) . External ears 28 of the body 10 have respective slots 30 for the passage of bolts interconnecting the two counterposed flanges of the conduit for sealingly clamping the annular part 12 between these flanges.

Referring to Figures 2 to 4, the body 10 is constituted by two pieces of rigid synthetic material, both indicated 10a.

All the parts of the two pieces 10a which have been described as forming part of the body 10 are designated, in Figures 3 and 4, with the same reference numerals followed by the letter a (annular parts 12a, projections 14a, ears 28a, slots 30a) .

In the assembled condition of the valve the two pieces 10a fit together along a median plane containing the axis of rotation of the shaft 20.

The two mating pieces 10a can have shapes which are at least substantially mirror images of one another, but in the preferred embodiment, shown in the drawings, these are identical with one another in order to be obtained by moulding in the same mould.

The preferred rigid synthetic material for the two pieces 10a is a so-called technopolymer, and in particular a polyamide 66 reinforced with glass fibres and heat stabilised.

Each of the mating pieces 10a preferably has a hollow internal structure delimited by a continuous outer wall of substantially C-shape section open towards the other piece 10a. As can be seen in Figures 2 to 4, the cavity of the piece 10a contains a network of reinforcing partitions designated 32.

A reticular structure of this type makes it possible to form extremely light pieces 10a of very high mechanical strength in a so-to-say "bone-like" structure.

This "bone-like" structure is not, however, best able mechanically to resist pressures of the fluid which act in the lumen 16.

The mechanical resistance to these pressures is provided by the metal insert 24 which will be described in more detail hereinbelow.

Preferably, as illustrated in Figures 1 and 3, the two matching pieces 10a are held together by bolts 34 (screws and nuts) which have the simple function of securely holding them together when the valve is not fitted.

Preferably, to guarantee a secure mutual positioning of the two pieces 10a, in particular in a first phase of assembly of the valve, each has, on one side of the axis of the shaft 20, projections 36 (Figure 4) in the form of pins which engage in corresponding blind holes 38 of the other piece 10a.

More preferably, as illustrated in Figures 3 and 4, the two mating pieces 10a have aligned holes 40 formed in their annular part 12a.

Pins 42 are pressed in with a force fit into these holes 40 and, as well as contributing to the interconnection with the two pieces 10a, guarantee resistance against mutual rotation about the central axis of the annular parts 12a. The pins 36 are preferably constituted by small steel cylinders.

Referring to figures 2 and 3, the metal insert 24 has diametrally opposite holes 44 through which the shaft 20 extends .

The seal 26 is constituted by an elastomeric facing which is preferably vulcanised onto the insert 24.

In particular, in the preferred embodiment shown in the drawings, this facing comprises a layer 46 which clads the inner cylindrical surface of the insert and is sealingly engageable by the periphery of the shutter 18. The facing preferably further includes, in one piece with the layer 46, annular end parts 48 which clad opposite annular front faces of the insert 24. These annular end parts 48 project axially from the lumen 16 of the body 10 to provide a seal between the insert 24 and the two flanges of the conduit.

Preferably, the seal 26 further includes, in one piece with the layer of elastomer 46, diametrally opposite bush parts 50 which clad the diametrally opposite surfaces of the holes 44 to provide a seal between the insert 24 and the shaft 20.

Preferably, as illustrated in Figures 2 to 4, adjacent the holes 44 and the bush parts 50 of the insert 24 the two pieces 10a of the body 10 have respective seats 52. Each of these seats 52 contains a respective bearing 54 (Figures 2 and 3) constituted by an insert of self-lubricating synthetic material in the form of an arcuate pad, each having a central hole 56 traversed by the shaft 20.

The hole 56 of each bearing 54 which opens onto the face thereof directed towards the shutter 18 has an annular seat 58 in which is housed an O-ring 60 which forms a seal between the shutter 18 and the associated bearing 54.

The shaft 20 is positioned axially by means of Seeger rings 62 housed in corresponding grooves 64 of the shaft 20 and which abut on the faces of the bearings 54 furthest from the shutter 18.

Claims

1. An interception and regulation valve for fluids, comprising: a body (10) having an annular part (12) intended to be clamped between two counterposed flanges of a conduit and defining a cylindrical lumen (16) for the passage of fluid, and a projection (14) extending radially from the annular part (12) , a disc-like shutter (18) of the butterfly type rotatable in the lumen (16) of the annular part (12), an operating shaft (20) extending diametrally through the lumen (16) and the interior of the projection (14) of the body (10), and to which the shutter (18) is fixedly connected for rotation, and an annular seal (26) acting as a valve seat, situated within the lumen (16) of the annular part (12) of the body (10) and with which the shutter (18) is able to cooperate peripherally to form a seal, characterised in that the body (10) is constituted by two pieces (10a) of rigid synthetic material having an at least substantially specular form with respect to one another and mating along a median plane containing the axis of the operating shaft (20), in the lumen (16) of the annular part (12) of the body (10) there is fitted a metal annular insert (24) having a form of a body of revolution, traversed diametrally by the operating shaft (20) and having two diametrically opposite holes (44) at which the shaft (20) is rotatably supported, and the seal (26) includes a layer (46) of elastomer which clads at least one inner cylindrical surface of the insert (24) and is sealingly engageable by the periphery of the shutter (18) .

2. A valve according to Claim 1, characterised in that the seal (26) further includes annular end parts (48) integral with the said layer of elastomer (46), which clad opposite annular frontal faces of the insert (24) and which project axially from the lumen (16) of the body (10) to form a seal between the insert (24) and the two flanges of the conduit.

3. A valve according to Claim 1 or Claim 2, characterised in that the seal (26) further includes diametrically opposite bush parts (50) integral with the said elastomeric layer

(46) , which clad the surfaces of the said diametrically opposite holes (44) to form a seal between the insert (24) and the shaft (20) .

4. A valve according to any of claims from 1 to 3, characterised in that the seal (26) is vulcanised to the insert (24) .

5. A valve according to any preceding claim, characterised in that the annular parts (12a) of the two mating pieces (10a) have aligned holes (40) , and in that the two pieces are fixed against angular movement about the central axis of these annular parts (12a) by pins (42) which extend into these aligned holes (40) with a force fit.

6. A valve according to Claim 5, characterised in that the said pins (42) are constituted by small metal cylinders.

7. A valve according to any preceding claim, characterised in that each of the two mating pieces (10a) of rigid synthetic material has a hollow internal structure delimited by a continuous outer wall of substantially C-shape section, open towards the other piece (10a) and the cavity of which contains a network of reinforcing partition walls (32) .

8. A valve according to any preceding claim, characterised in that the two mating pieces (10) are identical to one another and each has projections (36) in the form of pins engaged in corresponding blind holes (38) of the other piece (10a) .

9. A valve according to any preceding claim, characterised in that the two pieces (10a) of the body (10) are made of technopolymer.

10. A valve according to Claim 9, characterised in that the technopolymer is a polyamide (66) reinforced with glass fibres and heat stabilised.

11. A valve according to Claim 9 or Claim 10, characterised in that adjacent the said diametrically opposite holes (44) of the annular insert (24) the two mating pieces (10a) of the body (10) define respective seats (52) each containing a bearing (54) constituted by an insert of self-lubricating synthetic material having a hole (56) traversed by the shaft (20) .