GB1592732A

GB1592732A - Pipeline valves

Info

Publication number: GB1592732A
Application number: GB321178A
Authority: GB
Original assignee: Otto Tuchenhagen GmbH and Co KG
Current assignee: Otto Tuchenhagen GmbH and Co KG
Priority date: 1977-01-29
Filing date: 1978-01-26
Publication date: 1981-07-08
Also published as: BE863413A

Description

(54) IMPROVEMENTS IN OR RELATING TO PIPELINE VALVES (71) We, OTTO TUCHENHAGEN GMBH & CO. KG, (formerly OTTO TUCHENHAGEN), A German Company, of Berliner Strasse 4, 2059 Büchen, Federal Republic of Germany, 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 described in and by the following statement: The present invention relates to doubleseat pipeline valves, for example, for use in the foodstuffs industry.

Double-seat pipeline valves have two valve discs which to a limited extent are independent of one another and are movable relative to one another. Generally one valve disc is rigidly connected to a drive and is arranged during its stroke movement to necessarily move the other valve disc. The valve discs enclose between them a leakage cavity both when in the closed position and when in the open position, and this leakage cavity is provided with appropriate inlet and outlet paths for the admission of cleaning fluids and for the discharge of both cleaning and leakage fluids.

In such known pipeline valves the drive means for the valve discs, and also all the connecting pipes, leading to the leakage cavity, which are necessary for discharging and indicating leakage liquid and for the supply and discharge of fluids required by cleaning processes, are introduced into the valve housing from two oppositely situated sides. In many applications this is disadvantageous.

According to the invention there is provided a double-seat pipeline valve comprising two valve discs disposed within a valve housing having an inlet and an outlet, the valve discs being movable relative to one another and each being movable relative to a respective valve seat, to open and close the valve, wherein one of the valve discs is smaller than the other, the smaller valve disc being rigidly connected to drive means by way of a valve rod for movement with respect to its respective valve seat, the movement of said smaller valve disc being arranged to move the other, larger valve disc with respect to its respective valve seat, said larger valve disc being connected to a hollow rod which surrounds said valve rod and defines an annular gap therebetween, wherein both in the closed position and the open position of the pipeline valve the valve discs define between them a leakage cavity which is communicated externally of the valve housing by at least one connecting path extending through the side of the valve housing facing the drive means, the annular gap forming part of the connecting path.

With a pipeline valve of the invention, cleaning liquid can be introduced into the leakage cavity through the annular gap between the valve rods, this ensures sanitary or chemically and mechanically clean conditions.

Furthermore, with a pipeline valve of the invention it is possible for both the drive means for the valve discs and all connecting pipes, leading to the leakage cavity, which are necessary for discharging and indicating leakage liquid and for the supply and discharge of fluids required by cleaning processes, to be introduced into the pipeline switch housing from one side. This enables the valve to be used in situations where for reasons of layout the second side of the valve housing, through which connecting pipes have previously been introduced, is not available.This case exists for example when the second side of the pipeline valve has to be disposed at a minimum distance from a fixed boundary, or when a pipeline valve (for example in the form of a corner valve) is disposed directly on a container and the outlet pipe serving to discharge leakage and cleaning liquids would project into the container.

In an embodiment the annular gap between the rods serving to drive the valve discs and disposed concentrically one in the other forms one connecting path, and the hollow valve rod connected to the valve disc lying the greatest distance from the valve drive means forms a second connecting path between the leakage cavity and the environment of the valve housing. Two possible forms of connection in respect of indication and discharge of leakage liquid and supply and discharge of fluids required by cleaning processes are described herein. In the usual case the fluids required by cleaning processes are introduced through the hollow, inner valve rod. The annular gap lying on the outside then serves for the discharge of these fluids and of the leakage liquid.

In an embodiment, the hollow inner valve rod is dispensed with thereby simplifying the construction. In this embodiment the second connecting path between the leakage cavity and the environment of the pipeline valve housing is not provided,and it is no longer possible to clean the leakage cavity when both valve discs are in the closed position.

Where only one connecting path is provided it serves as the outlet for leakage liquid and/or for cleaning fluids. The cleaning fluids may be introduced into the leakage cavity from the part of the housing facing the drive means when the smaller valve is in the closed position, by raising the larger valve disc. Alternatively, cleaning fluids may be introduced into the leakage cavity from the other part of the housing, when the larger valve disc is in the closed position, by raising the small valve disc off its seat to establish communication between the other part of the housing and the leakage cavity.

In an embodiment the pipeline valve drive means is arranged to lift the smaller valve disc for the introduction of cleaning fluids, and a stroke limiter is provided to ensure that the smaller valve disc does not contact the larger disc and thus close the cleaning path. The stroke limiter also ensures that the larger valve disc is not moved from its closed position.

In an embodiment, cleaning of the leakage cavity is possible both in the closed position and in any open position of the pipeline valve. This is achieved by providing lifting devices, which are in each particular case connected to the rods driving the valve discs, and which are caused by a second drive to perform a relative movement towards one another. An annular gap is thus freed between the valve discs.

In an embodiment, an annular nozzle is formed at the end of the annular gap leading into the leakage cavity. Additionally, or alternatively, an elastic deflector may be disposed at the end of the annular gap leading into the leakage cavity. This elastic deflector is provided with a sealing lip movable with respect to a sealing seat formed on the larger valve disc.The elastic deflector performs the following functions when the cleaning fluids are supplied to the leakage cavity through the annular gap: sealing of the annular gap against the penetration of leakage medium; admission of cleaning fluids into the leakage cavity against a resistance such that the annular gap is completely filled and flushed out; guiding of the incoming cleaning fluid by the sealing lip of the deflector, which lip when lifted off its sealing seat on the top valve disc forms a gap in the form of an annular nozzle, onto the inner surfaces of the leakage cavity which are to be cleaned.

Embodiments of the present invention will hereinafter be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a cross-section through an embodiment of a pipeline valve according to the invention, which has two connecting paths between a leakage cavity and the environment of the valve housing; Figure 2 is a cross-section through a further embodiment of a pipeline valve according to the invention, having one connecting path; and Figure 2a shows a detail of a push rod for the pipeline valve of Figure 2.

A pipeline valve housing 1 comprising parts 2 and 3, contains a smaller valve disc 6 and a larger valve disc 5 (Figure 1). The smaller valve disc 6 is independently driven and rests on a smaller valve seat 4a. The smaller valve disc 6 is connected by way of a valve rod 9 and a rod head 14 to drive means 10 - 13 for the pipeline valve. The drive means 10 - 13 is connected with a crossmember 25 and consists of a drive housing 10, a piston 11, a working fluid connection 12, and a drive spring 13. The larger valve disc 5, which is driven in dependence on the smaller valve disc 6, lies on a larger valve seat 4 and is supported, via a hollow rod Sa and a connector Sb, by a spring 15 which acts against the rod head 14. The spring 15 applies prestressing forces both in the open position and in the closed position of the pipeline valve. The valve rod 9 is guided concentrically in the hollow rod Sa and together with the latter forms a bearing annular gap 18, which connects a leakage cavity 7 formed by the valve discs 5 and 6 to a connection opening Sc provided in the connector Sb. A second connecting path between the environment of the pipeline valve and the leakage cavity 7 is formed by a bore 19 which is provided in the valve rod 9 and which by way of openings 20 leads into the leakage cavity 7. The hollow rod Sa is on the one hand mounted and sealed by means of a bearing and sealing point 8 in the valve housing 1, and on the other hand sealing is effected between the hollow rod Sa and the valve rod 9 by means of a groove 16 in the connector Sb and a sealing ring 17. In Figure 1 the pipeline valve is shown in the closed position.

When the pipeline valve is operated, working medium, for example compressed air, is passed through the working fluid connection 12 into the drive housing 10 to move the piston 11. Movement of the piston 11 lifts the smaller valve disc 6 off the smaller valve seat 4a by way of the valve rod 9. During this movement of the smaller valve disc 6 valve leakage passes out of the valve housing part 3 into the leakage cavity 7 until the smaller valve disc 6 comes to bear against the larger valve disc S and forms a seal against the latter through the continuing action of the spring 15. As the upward movement of the piston 11 continues, the larger valve disc 5 is also lifted off the larger valve seat 4, so that communication between the valve housing parts 2 and 3 is established.When the pipeline valve is in the open position the spring 15 also ensures that the leakage cavity 7 is closed to the medium inside the valve housing parts 2 and 3.

The pipeline valve is closed in a similar manner but in the reverse sequence to that for the opening operation described by flowing working medium out of the drive housing 10. Here again valve leakage passes from the valve housing part 3 into the leakage cavity when the larger valve disc S has reached the larger valve seat 4 and the smaller valve disc 6 is moving from its position in which it bears against the larger valve disc S to the smaller valve seat 4a. The annular gap 18, in conjunction with the connection opening Sc, supplies fluids for a cleaning process (hereinafter referred to as cleaning fluids) by way of a port A to the leakage cavity 7, whereas the valve rod bore 19 leading into openings 20 serves to discharge the leakage liquid on the one hand and the cleaning fluids on the other hand out of a port B.If the valve rod 9 together with the larger valve disc 5 is lifted off the valve seat 4 in the direction C, during the further course of the movement the smaller valve disc 6 comes to bear against the larger valve disc S and also moves it into the open position. In this open position the cleaning or draining-off of leakage liquid can also be effected in the manner already described above. The valve rod bore 19 leading into openings 20 supplies to the leakage cavity 7, in another mode of operation, the fluids required by the cleaning process, which are passed thereto by way of the bore B, whereas the bearing annular gap 18 in conjunction with the connection opening Sc discharges these fluids and the leakage liquid by way of the port A.

The pipeline valve shown in Figure 2 has a single connection path between its environment and the leakage cavity 7. The second connecting path provided inside the valve rod 9 in Figure 1 does not exist. Both in the closed position and in the open position of the pipeline valve the bearing annular gap 18 in conjunction with the connection opening Sc and the bore A forms the outlet path for leakage liquid and/or for fluids required by the cleaning process, for discharge trom the leakage cavity 7. The discharge of the leakage liquid from the leakage cavity 7 in the closed position of the pipeline valve is indicated in the left-hand half of Figure 2, while the discharge of the fluids required by the cleaning process is indicated in the right-hand half of Figure 2.

The remainder of the construction of the pipeline valve according to Figure 2 corresponds to that shown in Figure 1 with the exception of the features which will now be described. The cleaning of the leakage cavity 7 in conjunction with the valve seat 4 is made possible by the fact that in the closed position of the smaller valve disc 6 the larger valve disc S is lifted by a lifting device which is adapted to be operated, independently of the pipeline valve drive means, by means of a second drive (not shown). This second drive is connected to the hollow rod Sa or to the connector Sb at a suitable point outside the valve housing 1; thus, upon operation of the second drive an annular gap S is defined between the larger valve disc S and the valve seat 4.Cleaning fluids can then enter the leakage cavity 7 through the annular gap S and pass out of the port A (right-hand half of Figure 2).

The second drive (not shown) applies a force D on a lifting device 22, and in the example illustrated, this force is transmitted by a push rod 23. The force D is opposed by a reaction force on the valve housing 1 at a point which will not be further designated here and which will be determined by the constructional arrangement of the push rod drive. In order to prevent in all circumstances the lifting of the smaller valve disc 6 off the smaller valve seat 4a by the push rod 23, the latter is given a limited stroke H (Figure 2a). The push rod 23 can act, that is to say it can operate the lifting device, only as long as the larger valve disc 5 forms with the larger valve seat 4 an annular gap S whose axial length is smaller than that which is required for optimum cleaning and which should be achieved through the stroke H of the push rod 23.

In this construction of the pipeline valve it is possible to clean the leakage cavity from the valve housing part 3. For this purpose the smaller valve disc 6 must be lifted off the smaller valve seat 4a. , while the larger valve disc S remains in its closed position. The driving force E is supplied by a second drive which works independently of the pipeline valve drive and which acts, for example through a push rod 23a, on a lifting device 22a connected outside the valve housing 1 to the valve rod 9 or rod head 14. The force E acting on the lifting device 22a is supported as reaction force on the valve housing 1. In order in all circumstances to prevent the larger valve disc S from being lifted off the larger valve seat 4a by the push rod 23a, the latter is given a limited stroke H' (Figure 2).

The push rod 23a can act, that is to say can operate the lifting device 22a only as long as the smaller valve disc 6 is at a distance from the larger valve disc S greater than the necessary safety distance. Maintaining this safety distance ensures that the larger valve disc S will remain in its closed position as required.

The second drive, which is not illustrated, can be dispensed with if the smaller valve disc 6 is lifted through the operation of the valve rod 9 in the direction C by means of the pipeline valve drive means (10 to 13). A stroke limiting means 24, which can be controlled in the directions F, limits the stroke movement in the direction C, so that it is ensured that the smaller valve disc 6 will not come to bear against the large valve disc S and thus close the cleaning path to the leakage cavity 7.

Cleaning of the leakage cavity 7 both in the closed position and in any open position of the pipeline valve is possible by means of the second drive which is independent of the pipeline valve drive means. This second drive applies to the lifting devices 22, 22a forces D which are able under all operating conditions to press the rod head 14 against the connector Sb, so that an annular gap is formed between the valve discs S and 6.

WHAT WE CLAIM IS: 1. A double-seat pipeline valve comprising two valve discs disposed within a valve housing having an inlet and an outlet, the valve discs being movable relative to one another and each being movable relative to a respective valve seat to open and close the valve, wherein one of the valve discs is smaller than the other, the smaller valve disc being rigidly connected to drive means by way of a valve rod for movement with respect to its respective valve seat, the movement of said smaller valve disc being arranged to move the other, larger valve disc with respect to its respective valve seat, said larger valve disc being connected to a hollow rod which surrounds said valve rod and defines an annular gap therebetween, wherein both in the closed position and the open position of the pipeline valve the valve discs define between them a leakage cavity which is communicated externally of the valve housing by at least one connecting path extending through the side of the valve housing facing the drive means, the annular gap forming part of the connecting path.

2. A pipeline valve as claimed in Claim 1, wherein the annular gap connects the leakage cavity to a first port external of the valve housing, and the valve rod has a bore opening into the leakage cavity and connecting the leakage cavity to a second port external of the valve housing.

3. A pipeline valve as claimed in Claim 2, wherein the annular gap is arranged to supply cleaning fluids to the leakage cavity, whereas the valve rod bore, which is disposed in the valve rod, is arranged for discharge of the cleaning fluids and for discharge of leakage fluid.

4. A pipeline valve as claimed in Claim 3, wherein the annular gap is connected to the first port directly by way of a connection opening in a connector.

S. A pipeline valve as claimed in Claim 2, wherein the valve rod bore is arranged to supply cleaning fluids to the leakage cavity, while the annular gap is arranged to discharge cleaning fluids and leakage fluid to the first port.

6. A pipeline valve as claimed in Claim 1, wherein both in the closed position and in the open position of the pipeline valve the annular gap, in conjunction with a connection to a first port, constitutes an outlet path for leakage fluid and/or for cleaning fluids discharged from the leakage cavity.

7. A pipeline valve as claimed in Claim 6, further comprising a first lifting device for raising the larger valve disc off its seat, said first lifting device being arranged to be operated by means of a second drive independently of the valve drive means, said first lifting device being connected to the hollow rod or to a connector at a suitable point outside the valve housing, whereby upon operation of said first lifting device when the smaller valve disc is in its closed position, a first annular gap is defined by said larger valve disc and its respective seat.

8. A pipeline valve as claimed in Claim 7, further comprising a second lifting device for raising the smaller valve disc off its seat, said second lifting device being arranged to be operated by means of said second drive, said second lifting device being connected to the valve rod or to the rod head at a suitable point outside the valve housing, whereby upon operation of said second lifting device when the large valve disc is in its closed position, a second annular gap adequate for the first annular gap is defined between the smaller valve disc and its respective seat.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. is possible to clean the leakage cavity from the valve housing part 3. For this purpose the smaller valve disc 6 must be lifted off the smaller valve seat 4a. , while the larger valve disc S remains in its closed position. The driving force E is supplied by a second drive which works independently of the pipeline valve drive and which acts, for example through a push rod 23a, on a lifting device 22a connected outside the valve housing 1 to the valve rod 9 or rod head 14. The force E acting on the lifting device 22a is supported as reaction force on the valve housing 1. In order in all circumstances to prevent the larger valve disc S from being lifted off the larger valve seat 4a by the push rod 23a, the latter is given a limited stroke H' (Figure 2). The push rod 23a can act, that is to say can operate the lifting device 22a only as long as the smaller valve disc 6 is at a distance from the larger valve disc S greater than the necessary safety distance. Maintaining this safety distance ensures that the larger valve disc S will remain in its closed position as required. The second drive, which is not illustrated, can be dispensed with if the smaller valve disc 6 is lifted through the operation of the valve rod 9 in the direction C by means of the pipeline valve drive means (10 to 13). A stroke limiting means 24, which can be controlled in the directions F, limits the stroke movement in the direction C, so that it is ensured that the smaller valve disc 6 will not come to bear against the large valve disc S and thus close the cleaning path to the leakage cavity 7. Cleaning of the leakage cavity 7 both in the closed position and in any open position of the pipeline valve is possible by means of the second drive which is independent of the pipeline valve drive means. This second drive applies to the lifting devices 22, 22a forces D which are able under all operating conditions to press the rod head 14 against the connector Sb, so that an annular gap is formed between the valve discs S and 6. WHAT WE CLAIM IS:

1. A double-seat pipeline valve comprising two valve discs disposed within a valve housing having an inlet and an outlet, the valve discs being movable relative to one another and each being movable relative to a respective valve seat to open and close the valve, wherein one of the valve discs is smaller than the other, the smaller valve disc being rigidly connected to drive means by way of a valve rod for movement with respect to its respective valve seat, the movement of said smaller valve disc being arranged to move the other, larger valve disc with respect to its respective valve seat, said larger valve disc being connected to a hollow rod which surrounds said valve rod and defines an annular gap therebetween, wherein both in the closed position and the open position of the pipeline valve the valve discs define between them a leakage cavity which is communicated externally of the valve housing by at least one connecting path extending through the side of the valve housing facing the drive means, the annular gap forming part of the connecting path.

9. A pipeline valve as claimed in Claim

8, wherein each lifting device is operated by way of a respective push rod having a limited stroke.

10. A pipeline valve as claimed in Claim 7, further comprising a stroke limiter for the valve rod arranged to be controlled in a direction substantially transversely to the extent of the valve rod, whereby upon operation of the valve drive means when the larger valve disc is in its closed position the smaller valve disc is lifted off its seat, the stroke of the valve rod being limited so that said valve discs define a further annular gap adequate for said first annular gap.

11. A pipeline valve as claimed in Claim 10, wherein said first lifting device is operated by way of a push rod having a limited stroke.

12. A pipeline valve as claimed in Claim 6, further comprising a first lifting device for raising the larger valve disc off its seat and a second lifting device for raising the smaller valve disc off its seat, wherein the lifting devices are caused to perform a relative movement towards one another by a second drive independent of the valve drive means, so that between one of the valve discs and its respective seat or between the valve discs an annular gap is formed.

13. a pipeline valve as claimed in any preceding claim, wherein the annular gap is formed at its end leading into the leakage cavity as an annular nozzle.

14. A pipeline valve substantially as hereinbefore described with reference to and as illustrated in Figure 1 or Figure 2 of the accompanying drawings.