WO1992022761A1

WO1992022761A1 - Butterfly valve of the intermediate flange type

Info

Publication number: WO1992022761A1
Application number: PCT/DK1992/000185
Authority: WO
Inventors: Håkan JEPPSON
Original assignee: Jeppson Haakan
Priority date: 1991-06-12
Filing date: 1992-06-12
Publication date: 1992-12-23
Also published as: EP0678176A1; DK111791A; DK111791D0; DK168237B1; AU1985092A

Abstract

In a butterfly valve of the intermediate flange type a sealing sleeve (12) for the turnable plate (18) is mounted in the surrounding valve housing (8) without any particular holding engagement therewith. Instead, there is mounted in each of the opposed ends of the sleeve (12) a reinforcing ring (22, 24 or 28) seated in a holding groove in a manner such that the sealing sleeve (12) can be mounted around the valve plate (18) in being heeled over the associated valve shaft (20), and yet be stabilized by means of the reinforcing rings. The valve is well suited to satisfy high hygienic requirements.

Description

Butterfly valve of the intermediate flange type.

The present invention relates to a butterfly valve of the type which is indicated in the introductory clause of claim 1.

Butterfly valves are a relatively simple valve type consisting of a valve housing with a straight through- passage and with an annular inner sealing sleeve for. cooperation with a turnable valve plate, which, by means of a spindle protruding out through a hole in the seal¬ ing sleeve and in the housing, may be rotated 90° be¬ tween a transverse closing position in which the rim of the circular valve plate engages the sealing sleeve, and a lengthwise oriented opening position, in which the flat valve plate only forms an insignificant constric¬ tion of the throughpassage.

Valves of this sort are widely used in pipe systems in various processing plants. They may be produced as relatively cheap units, which for further cost minimiz¬ ing may be arranged so as to be mountable by welding, such that the costly screwed connections may be dis¬ pensed with. Hereby, however, it is a problem with the entirely conventional butterfly valves that the valves are difficult to remove for servicing.

On this background special so-called intermediate flange valves have been developed, in which the vital parts of the valve, viz. the valve plate, the sealing sleeve, and a surrounding housing portion, are fixed as an independent unit between opposite valve end members which abut the concerned surrounding housing portion in a sealed manner and are provided with outer, respective connecting stubs which are suitable for welding connec¬ tion with the abutting conduct pipes. By means of bolts, the said valve end members may be clamped to the inter¬ mediate unit, which in a corresponding manner may be disengaged and pulled out in a radial plane for servic- ing, without the end members needing to be separated from the connected pipes, the serviced unit in a cor¬ responding manner being mountable by a purely transverse insertion movement.

Hereby it has been natural to perceive the inter¬ mediate flange, placed between the end members and also called the valve housing, as a superior housing part, which carries at its interior the sealing sleeve and the valve.plate, while in the axial direction it forms a spacer member between the outer end members of the valve, such that when being clamped together, these need merely to be well sealing against this intermediate flange. While this is easily obtainable by using suit¬ able, axially acting sealing means between the end mem¬ bers and the intermediate unit, it is nevertheless a complication that these sealings need be established at all.

For the valves considered it is a quite important condition that the sealing sleeve around the valve plate may remain securely in place regardless of an occurring positive or negative pressure inside the valve. The surrounding rigid intermediate flange housing in itself will ensure that the sealing sleeve may resist an inner overpressure, and the intermediate flange portions may- very well receive and fasten the outer side of the seal¬ ing sleeve in such a manner that this will also be an¬ chored against an occurring negative pressure in the conduct, normally by way of a thickened outer portion on the sealing sleeve being held in an undercut annular groove in the inner side of the valve housing.

Furthermore it should be an aim that the valves are easy to clean on the inside, primarily by CIP-cleaning, and in this respect the conventional intermediate flange valves are not advantageous, among other reasons because of grooves occurring by the said axial sealings against the outer housing portions, in which grooves deposits may form during normal operation.

However, intermediate flange valves of the type mentioned in the introduction have already been pro¬ posed, in which the concerned disadvantages are somewhat counteracted. As an example, a valve is known from US-A-3,341,170, in which the tubular sealing sleeve extends entirely through the valve housing, such that it may provide sealing towards the outer housing portions with its own ends, whereby the additional sealing rings and associated grooves at these portions may be avoided. The inner side of the valve housing is embodied as a smooth surface, with no special holder means for the sealing sleeve, but in return this is made in a compli¬ cated manner, viz. consisting of an outer pipe portion of a rigid plastic material, onto the inner side of which an inner resilient sealing sleeve or pipe portion is surface bound, probably by vulcanization. Apart from the fact that this binding in itself constitutes a com¬ plication, it is quite unfortunate in a qualified con¬ nection that the sealing sleeve appears as a substanti¬ ally rigid unit, this meaning that the valve plate must necessarily be in an assemblable, but thus also divided connection with the spindle, as it will otherwise not be possible to mount the sealing sleeve around the valve plate. If or when the plate and the spindle are provided as one piece, this mounting must necessarily take place by the sealing sleeve being deformed so extensively that it may be heeled over the free end of the protruding spindle, and this cannot take place if the ring appears as a rigid element.

Immediately it is not especially problematic to let the spindle be separably connected with the valve plate, such that the spindle may be mounted after the sealing sleeve having been placed around the valve plate, but when the valve is subject to rigorous hygiene require¬ ments, this design is disadvantageous, as the joint face area between the spindle and the plate will represent a potential accumulation area for impurities. It should thus be an aim that the sealing sleeve is sufficiently resilient for being deformed so extensively that it may be heeled over the outer end of the valve spindle, whereby this may be in fixed connection with the valve plate in an advantageous manner. However,such an asso¬ ciated flexibility of the sealing ring will be disad¬ vantageous with respect to the fastening of the ring to a smooth inner surface of the surrounding valve housing.

Another relevant proposal is disclosed in US-A- 4,605,201, in which the sealing sleeve is profiled for gripping out around a corresponding profiled holding groove at the end edges of the valve housing. For one thing this requires that the cooperating portions be provided with special profilings, whereby the sealing sleeve is not particularly easy to mount, and for another thing it apparently applies also in connection with this proposal that it is required for the valve plate to be in separable connection with the spindle. It is the purpose of invention to provide a valve of the said kind which is of a simple design, and in which the sealing sleeve may be a simple and easily mountable part, even with the possibility of being heeled over the spindle, such that also in that respect the valve is suitable for being designed so as to satisfy high hy¬ gienic requirements.

According to the invention this is obtained by the valve being designed as indicated in the characterizing clause of claim 1. The valve housing may consist of a simple pipe portion, however slotted in a known manner for assembling around the valve plate, and the spindle thereof, and the housing needs no sort of special pro¬ filing for the required fastening of the sealing sleeve. The said reinforcing rings may be placed after the mounting of the sealing sleeve in its final position between the valve plate and the valve housing, and even though the sealing ring per se is sufficiently soft, it will, however, hereby be reinforced sufficiently for resisting a certain friction at the insertion mounting between the outer or end housing members as well as to be operatively stabilized in a desired manner.

The reinforcing rings may be mounted in annular grooves in the end surfaces of the tubular sealing sleeve, whereby they will be entirely removed from the fluid conducting area, where the inner side of the seal¬ ing ring will still project entirely out to the outer housing members.

However, in practice it has been found just as appropriate or even better that the reinforcing rings in the shape of rigid plastic rings are provided with the same inner diameter as the sealing sleeve and are in¬ serted in annular corner grooves in the ends of the sealing ring or pipe at the inner side thereof; it has been found that a plastic ring placed in this area by axial insertion is very suitable for forming an effi¬ cient and jointless sealing partly against the sealing sleeve and partly against the outer housing member, when the receiving groove in the sealing sleeve is suitably dimensioned.

As already suggested it is a substantial advantage that the sealing sleeve despite its final rigidity is easily deformable when being mounted on the valve plate, as the latter and its associated spindle may then be made in one piece, preferably with rounded mutual tran¬ sition areas, such that also hereby, the valve is easy to clean by CIP-cleaning.

It should be noted that from certain butterfly valves which are not of the intermediate flange type it is known to mount the sealing sleeve in such a manner that it has end members which project into opposite, annular recesses in the valve housing itself. In DE-C- 670,327 a variant is indicated, in which the inwardly facing recess wall is replaced by a distending holding ring corresponding to a piston ring, which may be mounted after the assembling of the other valve parts. However, a direct holding engagement is still employed between an undercut holding groove in the inner side of the valve housing and an annular bead on the outer side of the sealing sleeve, and apart from this, the use of the said holding ring will be extremely unfortunate in that at its overlapping end portions the ring will form an open, cornered space that is impossible to clean. It will be seen that relative to this it will be a signifi¬ cant advantage when the invention provides the possibil¬ ity of an axial insertion of a rigid and entirely closed holding ring.

In the following, the invention is explained in more detail with reference to the drawing, in which Fig. 1 is a partially sectional side view of an intermediate flange valve of a known design, Fig. 2 is a correspond¬ ing side sectional view of a valve according to the invention, and Fig. 3 is a corresponding sectional view of a modified valve according to the invention.

The known valve shown in Fig. 1 comprises opposed outer housing parts 2 which by means of bolts 4 are clamped around or against an interjacent flange housing 6, which in a diametral plane is slotted in two halves 8, profiled innermost for fastening a protruding profile portion 10 on an inner sealing sleeve 12, the outer end surfaces of the flange halves 8 being provided with annular grooves 14 for receiving respective sealing rings 16, which by the clamping of the outer housing parts 2 provide sealing against the plane inner sides of these portions. The turnable valve plate is shown by 18, and it is indicated that the spindle 20 thereof is led out through a hole in the sealing sleeve 12 and further out through a corresponding hole in the flange housing 6, which hole is formed by semi-circular recesses in the two housing halves 8. By loosening the bolts 4 and re¬ moving some of them, the entire intermediate unit be¬ tween the outer housing parts 2 may be drawn out radial¬ ly for servicing.

A quite corresponding valve according to the inven¬ tion is shown in Fig. 2. Here the intermediate housing portion 6 is reduced to a simple pipe flange or two abutting pipe flanges 8, respectively, underneath which the sealing sleeve 12 is placed as a self-supported ring or tube body, which entirely fills out the space under¬ neath the housing portion 6 and has an inner passage which is directly flush with the pipe passage in the outer housing parts 2.

In the outer flat sides of the sealing sleeve 12, Fig. 2, annular groove 22 are provided, in which a me¬ tallic supporting ring 24 is laid in. These rings will stabilize the sealing sleeve against contraction in the event of an occurring negative pressure in the pipe system, and also against expansion by an occurring posi¬ tive pressure, but in the latter case also the outer flange housing 6 will have a stabilizing effect.

In its free condition the sealing sleeve 12 is slightly wider than the flange housing 6, such that by the clamping of the outer housing parts 2 it will form a pressure sealing against these, and it will be seen that this sealing will be established also immediately next to the area designated by 26 at the respective transi¬ tions to the pipe passages in the outer housing parts 2, such that at these areas there will occur no groove formation.

By the mounting of the sealing sleeve 12 around the valve plate 18, it is decisive that the sealing sleeve is deformable in order to insert it over the protruding spindle, but also this is possible as a matter of course in connection with the invention, when only the support- ing rings 24 are not inserted until this mounting has taken place.

In Fig. 3, which shows a section through the di¬ ametral plane of the spindle, the modification has been made that the metallic supporting rings 24, cf. Fig. 2, have been replaced by inserted plastic rings 28 in re¬ cesses 22, which are open inwardly towards the pipe passage. Per se these rings 28 have a certain sealing effect against the the plane inner sides of*the outer housing parts 2, such that they may form a practically groove free sealing thereagainst, just as they will be particularly easy to mount in the sealing sleeve.

The valve housing 8 may be constituted by a simple, smooth pipe portion, which should merely be divided in two in a suitable manner for assembling around the valve plate and its spindle and opposite swivel. The housing may be divided longitudinally or transversely, and the two portions may have suitable semi-circular recesses for assembling around the spindle and swivel. The hous¬ ing may be fastened in a precisely centered position solely by the guiding effect of the bolts 4.

Claims

C L A I M S :

1. A butterfly valve of the intermediate flange type, comprising a tubular, preferably bifurcated valve housing, which is axially fixed between opposed outer housing members, and which contains a resilient, like¬ wise tubular sealing sleeve for cooperating with the periphery of a valve plate also comprised in the valve housing, which plate is rotatable, by means of a radial¬ ly protruding spindle, between a closed transverse posi¬ tion, in which it engages the sealing sleeve along its entire periphery, and an open position rotated outwards therefrom, which sealing sleeve in its free condition protrudes slightly from the opposed ends of the valve housing for forming an axial sealing against the outer housing members, means being provided for fastening the sealing sleeve towards the inner side of the valve hous¬ ing, characterized by the combination of the valve hous¬ ing being provided with a substantially smooth inner side, and the means for fastening the sealing sleeve being constituted by reinforcing rings, which at the respective opposed ends of the tubular sealing sleeve are embedded in receiving grooves in the sealing sleeve, the valve preferably being of the type, in which the valve plate is inseparably connected with the associated valve spindle.

2. A valve according to claim 1, characterized in that the reinforcing rings are embedded in annular grooves in the end edge walls of the sealing sleeve, in a radial distance outside the inner side of the sealing sleeve.

3. A valve according to claim 1, characterized in that the reinforcing rings are rigid rings, preferably of plastic, which are inserted in the axial direction in annular grooves in the ends of the sealing sleeve at the transition to the inner side thereof, which reinforcing rings fit closely axially to the sealing sleeve and the opposed outer housing parts, respectively.

4. A valve according to claim 1, characterized in that the valve housing is designed as a bifurcated simple smooth pipe portion, however with throughholes for the spindle and for a guiding swivel on the valve plate diametrically opposite to the spindle.