GB2096743A

GB2096743A - A double seat valve

Info

Publication number: GB2096743A
Application number: GB8200777A
Authority: GB
Original assignee: Holstein und Kappert GmbH
Current assignee: Holstein und Kappert GmbH
Priority date: 1981-02-21
Filing date: 1982-01-12
Publication date: 1982-10-20
Also published as: JPS57144355A; DE3106578C2; JPH0267164U; DE3106578A1; GB2096743B; AU545291B2; AU8062782A

Abstract

A double seat valve includes leakage control means and two valve discs (4, 5) which are displaceable independently of each other, one of the valve discs abuts against the outer valve disc during the opening process after displacement through a predetermined distance and forms with the second valve disc a chamber (14) from which a leakage fluid conduit extends into the surrounding air (10), and wherein a displacement rod (8) for the larger valve disc is guided by the hollow displacement rod (6) of the smaller valve disc. Both displacement rods (6, 8) extend into the region of the main displacement mechanism (7) and form an additional spring housing (17) in the centre (16) of the main displacement mechanism (7) between the spring elements (15) which oppose the piston (25) in the closing and/or opening direction. Stroke ensuring means (19, 24) and the spring abutment (18) disposed in the additional spring housing (17) ensure that the disc (5) is closed by direct action in the event of it becoming jammed open. <IMAGE>

Description

SPECIFICATION A double seat valve The present invention relates to a double seat valve including leakage control means and two valve discs which are displaceable independently of each other, one of the valve discs being abuttabie, after moving a predetermined distance, against the second valve disc during the opening operation and forming with the second valve disc a chamber from which a leakage fluid conduit extends into the open air, and wherein the displacement rod of the larger valve disc is guided by the hollow displacement rod of the smaller valve disc and both displacement rods form a stroke ensuring means and a spring abutment.

A double seat valve is known, for example, from German Ausiegeschrift 2 632 587. In this known arrangement, the end of the hollow stem, which concentrically surrounds the valve stem and which extends upwardly from the valve housing, is formed outside the valve housing as a connectionpiece which accommodates the lower connection face for connecting the stroke ensuring means and the spring abutment. The actual main displacement rod extends from this connectionpiece to a displacement cylinder located thereabove.By providing the connection-piece with stroke ensuring means and a spring abutment and by incorporating it between the actual valve housing and the displacement mechanism located thereabove, a large overall height is necessarily produced which is associated with considerable disadvantages -- especially if a double seat valve of this type is used in a valve complex or even at other places where a low overall height is desirable.

On the basis of a known double seat valve of the above-mentioned type, the invention now seeks to provide a remedy therefor and a valve whose overall height, compared with the known valve, is reduced by the height of the restoring spring of one valve disc, including the structural dimensions required for stroke ensuring purposes.

According to the present invention, there is provided a double seat valve including leakage control means and two valve discs which are displaceable independently of each other, one of the valve discs being abuttable against the outer valve disc during the opening process after displacement through a predetermined distance and forming with the second valve disc a chamber from which a leakage fluid conduit extends into the surrounding air, and wherein a displacement rod for the larger valve disc is guided by the hollow displacement rod of the smaller valve disc and both displacement rods comprise a stroke ensuring means and a spring abutment, characterised in that both displacement rods extend into the region of the main displacement mechanism and form an additional spring housing in the centre of the main displacement mechanism between the spring elements which oppose the piston in the closing and/or opening direction, the stroke ensuring means and the spring abutment being disposed in the additional spring housing.

According to a further embodiment of the invention, it is proposed that a stop ring be disposed on the displacement rod of the lower valve disc and one spring end abut against the stop ring, the hollow displacement rod having an enlarged portion whose lower end face forms the spring abutment, and that a stop face be provided at an internal end of this enlarged portion for stroke ensuring purposes.

As a modification, it is further proposed, according to the invention, that the stroke ensuring means be formed by blocking the enclosed compression spring of one valve disc.

The arrangement according to the invention permits the elimination of the necessity to incorporate the restoring spring, including the associated spring abutment and the stroke ensuring means, in the external region, i.e.

between the main displacement mechanism and the valve housing located therebelow. This results in a considerable reduction in the overall height which was hitherto conventional and inevitable with such valves. Considerable advantages arise hereby, especially if such double seat valves are incorporated in valve complexes which comprise a plurality of individual valves which are located beside and above one another.

The invention will be described further, by way of example, with reference to the accompanying drawing which comprises a vertical section through a double seat valve.

A double seat valve is illustrated in the embodiment shown in the drawing and comprises a double or two-part housing 1 having spherically formed housing halves 2 and 3. The housing 1 is designed as a multi-directional distributor and comprises different connections for a pipe system.

Two valve bodies in the form of valve discs 4 and 5 are displaceable independently of each other and are guided within the housing 1. The valve disc 4, which is the upper valve body in the plane of the drawing and in the installed position, is connected to a hollow displacement rod 6 which extends upwardly from the double housing 1 and is guided into the region of a main displacement mechanism 7. Mounted within the hollow displacement rod 6 is a second displacement rod 8 for the valve disc 5 which is the lower valve disc in the installed position. The second displacement rod 8 also extends from the housing 1 and extends as far as the region of the main displacement mechanism 7. In the lower region, this displacement rod 8 is connected to the leakage discharge conduit 9 via passages 10.For its part, the leakage discharge conduit 9 is formed by the surfaces of the pipe 11 and of the lower valve disc 5 and by the external surface of the lower portion of the hollow displacement rod 6'.

The hollow adjustment rod 6 and the displacement rod 8 define an annular gap or passage 12 therebetween which extends from a cleaning connection 13 to beneath a hollow chamber 14 formed by the valve discs 4 and 5. An outlet conduit 26 deflects cleaning fluid upwardly and communicates with this annular gap 14.

As already stated, the two displacement rods 6 and 8 extend into the region of the main displacement mechanism 7. Within the chamber 1 6, defined by spring elements 1 5, of the displacement mechanism 7, the hollow displacement rod 6 forms a spring housing 1 7 together with the spring abutments 1 8 and a stroke ensuring means 1 9. The compression spring 20 accommodated in housing 1 7 acts to press the lower, larger valve disc 5 against the associated valve seat 17, or if the upper valve disc 4 is raised from its seat 21, the compression spring 20 acts to press the lower larger valve disc 5 against the seat 21. A stop ring 22 is disposed on the displacement rod 8 of the lower valve disc 5 within the spring housing 1 7 and one spring end abuts against stop ring 22.In such a case, the hollow displacement rod 6 includes an enlarging portion which forms the spring housing 17, and the lower end face 23 of the thickened portion forms the actual spring abutment. A further stop face 24 is provided on the internal end of the enlarged portion and serves as a stroke ensuring means.

This stroke ensuring means may also be formed by locking or blocking the compression spring 20 enclosed in the spring housing 1 7.

As soon as the hollow displacement rod 6 is moved downwardly by the action of the associated displacement piston 25, the valve body 4 is lifted off its seat and, after travelling a short distance, abuts against the lower valve disc 5 which is under spring tension and by means of which the hollow chamber 14 is created between the two valve discs. This chamber 14 is connected to the leakage fluid line (pipe 11) which extends downwardly from the valve housing. When this region is being cleaned, the cleaning fluid is conducted through the cleaning connection 13, the annular passage 12 and the associated outlet conduit along the wall of the hollow displacement rod and reaches the chamber 14, from which it flows out along the opposite wali of the pipe 11.If the valve is closed, or if both valve bodies 4, 5 abut against their associated seats, cleaning fluid can also act upon the larger hollow chamber then formed.

The stroke ensuring means which is incorporated within the spring housing 1 7 seeks to prevent the lower valve body 5 from seizing in the open position. As soon as both valve discs 4 and 5 are moved from the open position to the closed position, the lower valve disc 5 is moved by the action of the compression spring 20. If, for any reason, however, the valve disc 5 should seize of jam, then in accordance with the embodiment shown, the stop face 24 abuts against the stop ring 22 and thereby releases the valve disc 5 from its jammed position, so that the valve disc 5 is moved again into its proper position by the action of the compression spring 20. This stroke ensuring action may also be achieved by the compression spring 20 being designed appropriately with its block formation.

Claims

1. A double seat valve including leakage control means and two valve discs which are displaceable independently of each other, one of the valve discs being abuttabie against the outer valve disc during the opening process after displacement through a predetermined distance and forming with the second valve disc a chamber from which a leakage fluid conduit extends into the surrounding air, and wherein a displacement rod for the larger valve disc is guided by the hollow displacement rod of the smaller valve disc and both displacement rods comprise a stroke ensuring means and a spring abutment, characterised in that both displacement rods extend into the region of the main displacement mechanism and form an additional spring housing in the centre of the main displacement mechanism between the spring elements which oppose the piston in the closing and/or opening direction, the stroke ensuring means and the spring abutment being disposed in the additional spring housing.

2. A double seat valve as claimed in claim 1, in which a stop ring is disposed on the displacement rod of the lower valve disc and one spring end abuts against the stop ring, the hollow displacement rod having an enlarged portion whose lower end face forms a spring abutment and in which a stop face is provided on the internal end of this enlarged portion for stroke ensuring purposes.

3. A double seat valve as claimed in claim 1, in which the stroke ensuring means is formed by blocking the enclosed compression spring of one valve disc.

4. A double seat valve substantially as herein described with reference to and as illustrated in the accompanying drawings.