Double-seat valve device

A double-seat valve device, with a valve seat region, includes a first circular cylindrical-shaped seat surface with a first diameter, which with a first sealing element forms a radial seal for a connection opening to a first housing part, and a second circular cylindrical-shaped seat surface with a second diameter smaller than the first, which with a second sealing element forms a radial seal for the opening to a second housing part. A third seat surface is arranged between the first and second surfaces. In a closed position of the first closing member, the contact region rests against the third seat surface, to form a solid-state stop for the contact region. A deflecting surface is arranged between the first and third seat surfaces. The deflecting surface has an outlet edge offset to the third seat surface. A direction vector at the outlet edge points away from the second sealing element.

FIELD

The application relates to a double-seat valve device.

Double-seat valve devices are used for example, in beverage and brewing industry equipment, in the food and dairy industry, the pharmaceutical industry and/or in the cosmetics industry. The purpose of the double-seat valve device is to separate incompatible products reliably.

BACKGROUND

Known double-seat valve devices comprise a first closing member with a first sealing element, a second closing member movable relative to the first closing member and having a second sealing element, and a valve housing with a first housing part and a second housing part and with a connection opening for communicating the first housing part with the second housing part. The closing members can be moved separately to allow single seat-lift separation while product is in the opposite housing, in particular for cleaning of the associated valve seats.

SUMMARY

It is the object of the present application to provide a double-seat valve device with a high processing reliability.

This object is achieved by a double-seat valve device comprising a first closing member with a first sealing element and a contact region, a second closing member movable relative to the first closing member and having a second sealing element, and a valve housing with a first housing part and a second housing part and with a connection opening communicating the first housing part with the second housing part, wherein an inner surface of the connection opening is provided with a valve seat region, comprising a first circular cylindrical-shaped seat surface with a first diameter, which together with the first sealing element forms a radial seal for closing of the connection opening to the first housing part, a second circular cylindrical-shaped seat surface with a second diameter, which together with the second sealing element forms a radial seal for closing of the connection opening to the second housing part, wherein the second diameter is smaller than the first diameter, a third seat surface which is arranged between the first seat surface and the second seat surface, wherein in a closed position of the first closing member the contact region of the first closing member rests against the third seat surface, so that the seat surface forms a solid-state stop for the contact region, and a deflecting surface, wherein the deflecting surface is arranged between the first seat surface and the third seat surface, the deflecting surface has an outlet edge which is offset to the third seat surface, and a direction vector at the outlet edge of the deflecting surface points in a direction away from the second sealing element.

A device for blocking or for controlling the flow of fluids, that is, gases and/or liquids, between two pipelines or housing parts, is referred to as a valve. The double-seat valve device comprises at least two valves, each with a sealing element and an associated seat surface, for blocking or controlling the flow of fluids between the first and the second housing part. The closing members with the sealing elements and the associated seat surfaces each form a radial seal. In connection with this application, a seal which makes a seal between a first component arranged radially inside the sealing plane, and a second component arranged radially outside of the sealing plane, is referred to as a radial seal. A seal in which the sealing surfaces are normal to the axis of the seal is referred to as a face seal or axial seal. An inner seat surface having a circular cross-section is referred to as circular cylindrical-shaped seat surface.

The first closing member and the housing both are rigid bodies that contact each other in the closed position. A rigid body in the context of the application is defined as a body the deformation of which is neglectable regardless of the forces exerted. The contact between two rigid bodies is referred to as solid-state contact. In a closed position the contact region and the third seat surface are in solid-state contact. A closing effect is obtained in the closed position of the first closing member due to the effect of a constraining force. In one embodiment, the constraining force is applied by a gravity force of the closing member. Alternatively or additionally, force elements are provided, for example, comprising magnets or restoring springs; which force the closing member into the closed position. The valve housing and the closing members in several embodiments are each made of stainless steel, so that the solid-state contact is a metal-to-metal contact. The sealing elements mounted to the closing members in one embodiment are designed as O-rings, which are installed in associated grooves of the closing members. The sealing elements are each in sliding contact with the seat surfaces in order to effect a seal in the closed position. Any wear on the sealing elements may reduce a sealing effect of the sealing elements. Due to the additional sealing effect by means of the solid-state contact, it is ensured that in this case as well, the products supplied in the first housing part and in the second housing part are reliably separated from each other. This also permits a cleaning and/or a sterilization during the production (“cleaning in place”—CIP, or “sterilization in place”—SIP), that is, without disassembly and even while at least one product is present in one housing part.

An opening of one valve is known as “seat-lifting”, short “lifting”, “venting” or “cycling.” Due to the solid-state contact, even when lifting the second closing member it is ensured that a sterilization and/or cleaning fluid used for rinsing of the second housing part and the second closing member does not come into contact with a product present in the first housing part.

In connection with this application a section of the valve seat region used to divert or deflect a fluid jet, in particular a jet of a sterilization- and/or cleaning fluid, also known as a steam jet, is called the deflecting surface. The deflecting surface is also referred to as the jet guide surface. The deflecting surface is provided with an outlet edge arranged offset to the third seat surface. In the context of the application, an offset arrangement of the outlet edge denotes a transition region in which a direction vector at the outlet edge does not coincide with a direction vector at the inlet edge of an adjoining surface, for example due to a discontinuity. Furthermore, an incline of the deflecting surface is selected such that a direction vector at the outlet edge of the deflecting surface points in a direction away from the second sealing element. The deflecting surface is in other words configured so as to avoid a direct impact of the fluid on the second sealing element and on the third seat surface. Direct impact of the fluid or of the fluid jet is referred to as a speed component of a fluid jet which is directed perpendicularly onto an element bounding a flow. A direct impact causes an impact force on the seal or the element bounding the flow, which results in a static pressure, also referred to as a stagnation pressure. Due to the static pressure, in the absence of a sealing element or in case of wear on the sealing element, a leakage flow may occur in case of direct impact. By means of the deflecting surface, a direct impact of the second sealing element and thus a leakage flow in the region of the second valve seat is prevented.

In other words, the deflecting surface between the first seat surface and the third seat surface is configured such that during lifting or cycling of the first closing member, a fluid jet arriving tangentially to the first seat surface is deflected by an angle of at least 90°. The deflected fluid jet features no velocity component which is directed perpendicularly onto the second sealing element bounding the flow. Thus, a direct impact of the radial seal and a resultant pressure increase on the radial seal are prevented. Preferably a leakage cavity is provided in the second closing member through which the deflected fluid jet can flow for discharge.

In one embodiment the deflecting surface is at least in one section concavely curved. In the context of the application a concavely curved section is defined as a bulge away from a center axis. Due to the concave curvature a reliable deflection of the fluid jet in the direction of the axis of the closing member is achieved. In one embodiment, the concave curved section has a configuration like that of a annular groove.

Another embodiment provides that the curvature of the deflecting surface has an inflection point and/or a point of discontinuity in a transition section to the third seat surface. In the context of the application, an inflection point denotes a location where the deflecting surface changes its curvature behavior, wherein in one embodiment, a convex curved section of the deflecting surface transforms into a concave curved section. A discontinuity point denotes a location where jumps or steps occur. Due to an inflection point and/or a discontinuity point, the deflecting surface has an opening edge offset to the third seat surface, so that a flow along the deflecting surface does not lead to a direct impact of the third seat surface.

In another embodiment, the first closing member is provided with a contact region cooperating with the third seat surface and with a circular cylindrical-shaped outside surface, wherein the diameter of the contact region is greater than the diameter of the second seat surface. The corresponding third surface in one embodiment has a tapered structure. In this embodiment, the contact region together with the third seat surface forms a semi-axial seal. Due to the diameter relationships, a safety in case of a pressure shock of the first closing member against a movement of the first closing member towards the second housing part is assured, independently of the level of a pressure shock.

In an alternative embodiment, the contact region of the first closing member is arranged at a front surface. In this embodiment, the contact region with the third seat surface forms an axial seal or face seal. For this purpose, the third seat surface in several embodiments is arranged, at least in sections, perpendicularly to the axial direction of the first closing members.

In one embodiment, the first closing member is provided with a conical section adjoining to the front surface. The conical section functions as a diffuser for the fluid jet. In addition, a guidance of the closing member moving towards the closing position is facilitated by means of the conical section. In case of a contact region with a circular cylindrical-shaped outside surface, the contact region is provided in one embodiment the conical section.

In another refinement, the first closing member is provided with an accommodation section having a circular cylindrical-shaped outer surface and a throttle section arranged between the accommodating section and a front surface facing the second closing member, said throttle section having a circular cylindrical-shaped outer surface, wherein the first sealing element is mounted at the accommodating section, and a diameter of the throttle section is larger than a diameter of the accommodating section. During a seat-lifting of the first closing member, in preferred embodiments, the first closing member is moved only by a short distance. Thus, the throttle section remains in the region of the connection opening. Due to the throttle section a jet of a cleaning fluid, in particular a jet of steam, is throttled, so that a pressure of the cleaning fluid downstream of the throttle section acting on the second sealing element is reduced.

In an additional embodiment, the second closing member is provided with an end section having an outer surface against at which the second sealing element is mounted. Preferably, on a front surface facing the second closing member, the first closing member is provided with a recess complementary to the end section of the second closing member, wherein the end section is insertable into the recess, so that this recess in any rotary position forms a sealing line with the outer surface of the end section. When opening the valve device, that is, when moving both closing members into an open position, the closing members are moved preferably to abut each other. For this purpose, in one embodiment the end section of the second closing member is inserted into the recess of the first closing member. Thus, a reliable contact between the closing members is ensured.

In an additional embodiment, the second closing member is provided with a leakage cavity having a conical inlet opening facing the first closing member. The inlet opening extends in one embodiment up to the outer surface of the second closing member. Hence, a stagnation point of an arriving fluid jet in the front region of the second closing member is avoided.

In several embodiments, the closing members are arranged for an independent movement for a seat-lifting—also referred to as cycling or venting. For a seat-lifting, one of the sealing elements is separated from its associated seat surface, whereas the other sealing element remains seated tightly against its associated seat surface. During the seat-lifting, a cleaning- or sterilization fluid can be supplied via the opened valve seat, which cleaning- or sterilization fluid is discharged in one embodiment via the leakage cavity. Upon opening of the valve device, the closing members rest against each other, so that the leakage cavity is separated from the products.

In further embodiments, the double-seat valve device is provided with a pneumatic valve drive. The pneumatic valve drive comprises in several embodiments a pneumatic cylinder, a first and a second piston seated so as to be displaced in the pneumatic cylinder, an outer shaft which connects the first closing member to the first piston for a transfer of movement, and an inner shaft arranged concentrically to the outer shaft, which connects the second closing member to the second piston for a transfer of movement. Due to the embodiment with outer and inner shaft, driving both closing members is possible from one side of the housing.

Preferably, the pneumatic cylinder is divided by the pistons into a first, a second and a third pressure chamber, wherein upon pressurizing of the first pressure chamber, both closing members can be moved jointly into an open position, upon pressuring of the second pressure chamber, the first closing member is lifted and upon pressurizing of the third pressure chamber, the second closing member is lifted.

In an additional embodiment, a traverse is provided by means of which the inner shaft is connected to the second closing member for a transfer of movement. The traverse is defined as a component comprising one or a plurality of webs extending in a radial direction, wherein free space remains between the webs. The traverse in one embodiment is provided with two webs arranged at a 180° offset. By means of the two webs, a control with sufficient stability is ensured. At the same time, ample free space is created between the webs through which a cleaning fluid is discharged.

In one embodiment the traverse is arranged on one end of the second closing member facing away from the first closing member. In another embodiment, a distance between the traverse and one end of the second closing member facing, the first closing member is smaller than a distance between the traverse and one end of the second closing member facing away from the first closing member. Thus, the movement of the second closing member connected to the shaft via the traverse is controlled in the region of the end associated with the valve seat region. This permits a stable control of the movement of the second closing member.

Other embodiments are defined in the dependent claims. Further advantages of the disclosure emerge from the claims and from the following description of exemplary embodiments of the disclosure, which are schematically illustrated in the drawings. Uniform reference signs are used in the drawings for equivalent or similar components. Features described or illustrated as part of one exemplary embodiment can likewise be used in another exemplary embodiment in order to obtain a further embodiment of the disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1shows cross-sectional view of a first exemplary embodiment of a double-seat valve device1. The double-seat valve device1comprises a valve housing2and being displaceably mounted therein are a first closing member3with a first sealing element30, and a second closing member4with a second sealing element40, which can move relative to the first closing member3. The valve housing2is designed with a first housing part20and a second housing part21and with a connection opening22communicating the first housing part20with the second housing part21.

In one application, the first housing part20is connected to a product tank (not illustrated) and the second housing part21is connected to a product line (likewise not illustrated).

A pneumatic valve drive5is provided for a joint or for a separate movement of the closing members3,4. The pneumatic valve drive5comprises a cylinder50, in which two working pistons51,52are displaceably mounted. The working pistons51,52are connected by valve shafts6,7to the closing members3,4for a transfer of movement. In the illustrated embodiment, an outer shaft6and an inner shaft7are provided as valve shafts6,7. The outer shaft6is connected to the first closing member3for a transfer of movement. The outer shaft6is a hollow shaft, wherein inside the outer shaft6the inner shaft7is moveably arranged, which inner shaft7is connected to the second closing member4for a transfer of movement.

For connecting the inner shaft7to the closing member4, in the illustrated exemplary embodiment a traverse72is provided with two webs arranged at a 180° offset, wherein the webs of the traverse72are merely indicated in the illustrated cross sectional view. A distance between the traverse72and one end of the second closing member4facing the first closing member3, is less than a distance between the traverse72and another end of the second closing member4facing away from the first closing member3. In the illustrated embodiment, the distance between the traverse72and the end of the second closing member4facing the first closing member3, amounts to between about 15 mm and about 25 mm.

The cylinder50is divided into three pressure chambers53,54,55by means of the two working pistons51,52. A compressed air supply (not illustrated inFIG. 1) is provided at each of the pressure chambers53,54,55for supplying compressed air to each chamber individually.

A first restoring spring56is arranged in the third pressure chamber55. The first restoring spring56is supported by a counter support57, which counter support57is arranged moveable in the third pressure chamber55. In the first pressure chamber53there is a second restoring spring58, which is braced against the working piston51and against an annular collar60provided on the outer shaft6. The restoring springs56,58are each designed as compression springs. The second restoring spring58is designed with smaller dimensions than the first restoring spring56, that is, a restoring force applied by the first restoring spring56in the case of an equal displacement, is greater than a restoring force applied by the second restoring spring58. Due to the counter support57, the first restoring spring56is disengaged during a movement of the first working piston51from the illustrated rest-position in the direction of the first pressure chamber53. That is, during a movement of the first working piston51from the illustrated rest-position in the direction towards the first pressure chamber53, a force applied by the first restoring spring56is prevented from acting on the working piston51. A movement of the working piston51from the illustrated rest-position in the direction towards the third pressure chamber55, however, does occur against the force of the first restoring spring56. Upon this movement of the working piston51, the counter support57is displaced by the first working piston51. The first working piston51is thus held in an equilibrium position due to the two restoring springs56,58. The second working piston52is provided with a stop520which prevents a displacement of the working piston52from the rest-position illustrated inFIG. 1for a reduction in the volume of the second pressure chamber54. Any movement of the second working piston52in the direction of the first pressure chamber53takes place against the force of the second restoring spring58. In addition, in the first pressure chamber53there is a retaining ring59, which limits the movement of the second working piston52in the direction of the first pressure chamber53.

In the illustrated exemplary embodiment, the inner shaft7connected to the second closing member4is translatory fixed to the first working piston51, which is located between the first pressure chamber53and the third pressure chamber55. Thus any axial movement of the first working piston51directly also causes an axial movement of the second closing member4.

The outer shaft6connected to the first closing member3is connected to the second working piston52via the annular collar60such that a displacement of the working piston52in the direction of the first pressure chamber53is transferred to the outer shaft6. However, in the illustrated usual orientation of the double-seat valve device1, an upward movement of the outer shaft6caused by an upward movement of the second closing member4is not trans-ferred to the working piston52. Thus it is possible to limit a movement of the outer shaft6caused by the second working piston52by means of the retaining ring59which acts as a stop for the working piston. However, the outer shaft6is moveable beyond the positioning limited by the retaining ring by means of other mechanisms for opening of the closing member3.

The closing member4is provided with a leakage opening41through which a leakage flow moving through the sealing elements30,40can be drained in the event of a defect.

FIG. 2shows a detail II according toFIG. 1in a view rotated with respect toFIG. 1, wherein the two closing members3,4are located in a closed position as inFIG. 1. This state is also referred to as the closed position of the double-seat valve device1. As shown inFIG. 2, at an inner surface of the connection opening22there is a valve seat region with a first seat surface22a, a second seat surface22band a third seat surface22c. The first seat surface22ais circular cylindrical shaped with a first diameter D_22a. The first sealing element30cooperates with the first seat surface22a, as shown, for closing of the connection opening22to the first housing part20(seeFIG. 1). The second seat surface22bis likewise circular cylindrical shaped with a second diameter D_22b, wherein the second diameter D_22bof the second seat surface22bis smaller than the diameter D_22aof the first seat surface22a. The second seat surface22bcooperates with the second sealing element40for closing of the connection opening22to the second housing part22(seeFIG. 1). The sealing elements30,40each are in a sliding contact with the seat surfaces22a,22b. The sealing elements30,40in the illustrated, closed position, thus form a radial seal with the seat surfaces22a,22b.

Furthermore, a third seat surface22cis provided which is arranged between the first seat surface22aand the second seat surface22b. The first closing member3is provided with a contact region31at a front surface which rests against the third seat surface22cin the illustrated, closed position of the first closing member3. Thus the closing member3forms an axial seal or face seal with the third seat surface22c. A constraining force is applied via the restoring spring58(cf.FIG. 1) engaged with the annular collar60and the gravity of the first closing member3. Said constraining force forces the contact region31against the seat surface22c, without additional supply of compressed air to the contact chambers53,54,55, so that a sealing effect is achieved owing to the solid-state contact between closing member3and seat surface22c.

A concavely curved deflecting surface23is formed between the first seat surface22aand the third seat surface22c. The concavely curved deflecting surface23does not transform continuously into the third seat surface22c. Rather, a step is provided between the deflecting surface23and the third seat surface22c, so that a fluid flowing along the deflecting surface23is not directed in the direction of the third seat surface22c. Thus, the deflecting surface23has an outlet edge, which is offset to the third seat surface22c.

A direction vector at the outlet edge of the deflecting surface23points normal to the second seat surface22band thus in the direction away from the second sealing element40.

By means of the illustrated double-seat valve device1acleaning and/or a sterilization is possible during the production (“cleaning in place” or “cleaning in process”—CIP or “sterilization in place/process”—SIP), that is, while a product is present in at least one housing part20,21.

With the valve closed (cf.FIGS. 1 and 2) for this purpose a cleaning- and/or sterilization fluid is removed through the leakage opening41and free spaces of the traverse72. An opening region44of the leakage opening41at the end of the second closing member4facing the first closing member3in the illustrated exemplary embodiment directly adjoins to the outer surface of the end region42, so that a planar front surface at the end is minimized or—as illustrated—is prevented. The opening region44in the illustrated embodiment proceeds discontinuously with a kink.

The first closing member3is provided with an accommodation section34having a circular cylindrical shaped outer surface at which the first sealing element30is mounted. In addition, at the front surface between the accommodation section34and the contact region31there is a throttle section36with a circular cylindrical shaped outer surface and a conical end region37. A diameter d_36of the throttle section36is larger than a diameter of the accommodation section d_34.

The second closing member4likewise is provided at its end section42with a circular cylindrical shaped outer surface at which the second sealing element40is mounted. On its front surface facing the second closing member4the closing member3is provided with a recess38complementary to the end section42of the second closing member4, so that the second closing member4is insertable into the recess38. A second recess39of smaller cross section adjoins the recess38.

As is evident inFIG. 1, the closing members3;4are configured as so called “balancers”, wherein in the region of a passage through the first housing part20and/or the second housing part21, respectively, the first closing member3and the second closing member4are each equipped with a diameter which is essentially equal to the diameter D_22aof the first seat surface22aor diameter D_22bof the second seat surface22b, respectively. Thus the risk of product contamination due to pressure surges or pressure shocks is further reduced.

The operation of the double-seat valve device1will be explained below with reference toFIGS. 1 to 5.

As shown inFIG. 1, due to a pressurization of the first pressure chamber53the working piston51is displaced against the force of the first restoring spring56. The displacement occurs in the upward direction in the illustrated standard orientation. Due to the displacement of the working piston51, the inner shaft7fixedly coupled to the working piston51and thus the closing member4are displaced in the direction of the first closing member3.

As illustrated inFIG. 3, due to the displacement the mutually facing ends of the closing members3,4abut each other. The end section42of the second closing member4is thereby inserted into the complementary recess38of the first closing member3. Thus, the sealing element40forms a radial seal with the recess38.

After the second closing member4is moved to abut the first closing member3by pressurization of the first pressure chamber53as described above, the movement of the second closing member4is transferred to the first closing member3and due to a further supply of compressed air into the first pressure chamber53, the two closing members3,4are moved together against the force of the first restoring spring56, so that the valve device1is opened and products present in the housing parts20and21are brought into contact with each other. As is evident fromFIG. 1, the force of the second restoring spring58arranged between the annular collar60of the outer shaft6and the first working piston51restrains a relative movement between the outer shaft6and the inner shaft7, and thus the closing members3,4, which might otherwise result in a separation of closing members3,4. In other words, the second restoring spring58forces the first closing member3connected to the outer shaft6in the direction of the second closing member4.

As is evident inFIG. 3, a cleaning is possible even with a valve in the open position. A sealing against the product is assured by the second sealing element40and a solid-state contact between the closing members3,4. A separation of the closing members3,4is prevented, as described above. A cleaning fluid can be drained through the leakage opening41.

As is evident fromFIG. 1, when compressed air is supplied to the second pressure chamber54, a movement occurs to allow seat-lifting of the first closing member3. Due to the supply of compressed air, the second working piston52is moved upwards until it reaches a stop formed by the retaining ring59. In the standard orientation of the double-seat valve device1as illustrated in the figure, the movement occurs in an upward direction. The second working piston52is connected to the outer shaft6via the annular collar60such that the movement of the working piston52is transferred to the outer shaft6for lifting the closing member3. Owing to the movement of the outer shaft6, the spring58arranged between the first working piston51and the outer shaft6in the first pressure chamber53is compressed. Thus, a force is exerted onto the first working piston51and thus also onto the inner shaft7fixedly connected to the first working piston51. However, in the rest-position illustrated inFIG. 1, one end61of the outer shaft6is arranged at a distance to the first working piston51. Thus, there is merely a transfer of force, but not a transfer of movement to the first working piston51. A displacement movement of the working piston51due to the acting force applied by the second restoring spring58is prevented by the first restoring spring56. The second closing member4is thus reliably held in a closed position.

FIG. 4shows schematically a detail of the double-seat valve device1according toFIG. 3, during lifting of the first closing member3. As shown inFIG. 4, during lifting of the first closing member3, the first closing member3is moved only for a short distance in the illustrated embodiment. The throttle section36remains in the region of the connection opening22. The conically tapered end region37adjoining the throttle section36acts as a diffuser. A jet, in particular a jet of steam of a cleaning fluid, is throttled by the throttle section36, so that a pressure of the cleaning fluid acting on the second sealing element40is reduced. An entering cleaning jet is additionally deflected by the deflecting surface23, as indicated schematically by the arrows, in the direction of the leakage opening41and away from the second sealing element40. Thus, the deflecting surface23prevents that a pressure is applied by the cleaning fluid onto the second sealing element40. In several embodiments, the deflection additionally causes a suction effect on the second sealing element40. The suction effect is also referred to as negative pressure. The cleaning fluid is drained through the leakage cavity41.

As shown inFIG. 1, lifting of the second closing member4is achieved by supplying compressed air to the third pressure chamber55. Due to the supply of compressed air, the working piston51is moved in such a manner that the inner shaft7fixedly connected to the first working piston51lifts the closing member4. The movement occurs downward in the standard orientation of the valve device1illustrated in the figures. As described, the end61of the outer shaft6is arranged at a distance to the first working piston51in the rest-position illustrated inFIG. 1. A displacement of the first working piston51downward thus will not be transferred directly onto the outer shaft6. A downward displacement of the outer shaft6is additionally prevented by means of the contact between the contact region31of the first closing member3and the seat surface22c. Finally, a downward displacement of the outer shaft6is also prevented by the stop520at the second working piston52. Due to the second restoring spring58provided between the first working piston51and the annular collar60of the outer shaft6, the outer shaft a constraining force acting in a downward direction is applied on the outer shaft6, and thus the first closing member3will be forced into the closed position.

FIG. 5shows schematically a detail of the double-seat valve device1according toFIG. 3during seat-lifting of the second closing member4. As is evident inFIG. 5, a reliable deflection of a cleaning jet—illustrated schematically by arrows—is achieved due to the second recess29.

FIG. 6shows a cross sectional view of second exemplary embodiment of a double-seat valve device1. The double-seat valve device1according toFIG. 6corresponds essentially to the double-seat valve device1according toFIG. 1, and consistent reference numbers are used for the same or similar components. A detailed description of components already described is thus omitted.

As is evident inFIG. 6, the first pressure chamber53is provided with a first compressed air port L1, the second pressure chamber54is provided with a second compressed air port L2, and the third pressure chamber55is provided with a third compressed air port L3.

In contrast to the embodiment according toFIG. 1, a traverse72, which connects the inner shaft7to the second closing member4, is arranged on one end of the second closing member4facing away from the first closing member3.

The exemplary embodiments differ further in the configuration of the valve seat region.FIG. 7shows a detailed view VII of the valve seat region according toFIG. 6.

FIG. 7shows a detail VII according toFIG. 6, wherein both closing members3,4are located in a closed position as inFIG. 6. This state is also referred to as the closed position of the double-seat valve device1. As shown inFIG. 7, a valve seat region with a first seat surface22a, with a second seat surface22b, with a third seat surface22c, is provided at an inner surface of the connection opening22. The first seat surface22ais circular cylindrical Shaped with a first diameter D_22a. The first sealing element30cooperates with the first seat surface22a, as illustrated, for closing of the connection opening22to the first housing part20(seeFIG. 6). The second seat surface22bis likewise circular cylindrical-shaped with a second diameter D_22b, wherein the second diameter D_22bof the second seat surface22bis smaller than the diameter D_22aof the first seat surface22a. The second seat surface22bcooperates with the second sealing element40for closing of the connection opening22to the second housing part21(seeFIG. 1). The sealing elements30,40are each in a sliding contact with the seat surfaces22a,22bin order to cause a radial seal in the illustrated, closed position. For increased reliability, a third conical seat surface22cis provided which is arranged between the first seat surface22aand the second seat surface22b. The first closing member3is provided with a contact region32, which rests against the third seat surface22cin the illustrated closed position of the first closing member3. An annular groove is provided between the first seat surface22aand the third seat surface22c, so that a concave curved deflecting surface23is formed. In the transition region between the first deflecting surface23and the third seat surface22cthere is an inflection point, and the concave curved deflecting surface23transforms into a convex curved transition region. Thus the deflecting surface23opens at an offset to the third seat surface22cand a fluid flowing along the deflecting surface23will not be guided in the direction of the third seat surface22c. A direction vector in one outlet edge of the deflecting surface23points in a direction away from the second sealing element40, wherein the fluid jet deflected by the deflecting surface23does not have a velocity component directed perpendicularly onto the sealing element40bounding the flow.

The contact region32of the first closing member3is provided with a cylindrical-shaped outer surface, wherein a diameter d_32of the contact region32is larger than a diameter D_22bof the second seat surface22b. This reliably prevents the first closing member3from being displaced past the illustrated closing position in the direction of the second housing part21.

A constraining force is applied via the first restoring spring58engaged with the annular collar60(cf.FIG. 6); said force forces the contact region32in the illustrated, closed position, into contact with the seat surface22c, without additional supply of compressed air to the ports L1, L2, L3, so that a sealing effect is obtained owing to the solid-state contact between closing member3and seat surface22c. Owing to the reliable seal, a cleaning and/or a sterilization is possible during the production, that is, while a product is present in at least one housing part20,21. A cleaning and/or sterilization fluid is discharged through the leakage opening41shown inFIG. 7. In the illustrated embodiment, cleaning channels33,43are provided so that the sealing elements30,40can be cleaned.

The first closing member3is provided with an accommodation section34with a circular cylindrical-shaped outer surface at which the first sealing element30is mounted, wherein a diameter d_34of the accommodation section34is larger than a diameter of the contact region d_32. In addition, a throttle section36with a circular cylindrical-shaped outer surface is provided between the accommodation section34and the contact region32, wherein a diameter d_36of the throttle section36is larger than a diameter of the accommodation section d_34.

The second closing member4is provided at its end section42with a tapered or conical outer surface, at which the second sealing element40is mounted. At its front surface facing the second closing member4, the first closing member3is provided with a recess38complementary to the end section42of the second closing element4.

The operation of the double-seat valve device1according toFIGS. 6 and 7corresponds to the operation of the double-seat valve device according toFIGS. 1 to 5.