Valve drive for a double-seat valve, and double-seat valve

Abstract

The invention relates to a valve drive for a double-seat valve, which comprises a first closing element (18) connected to a first valve stem (16) and a second closing element connected to a second valve stem (20), wherein the first closing element can be adjusted by means of the valve drive between a position interacting with a first valve seat (28) and a position lifted off from the first valve seat, and wherein the second closing element can be adjusted by means of the valve drive, independently of the first closing element, between a position interacting with a second valve seat (30) and a position lifted off from the second valve seat, wherein the valve drive has a first electric motor (36), wherein the first electric motor is positioned next to the first and / or the second valve stem, and wherein the valve drive has a second electric motor (52), wherein the second electric motor is positioned next to the first and / or the second valve stem. The invention also relates to a double-seat valve having said valve drive.

Description

[0001] Valve actuator for a double seat valve and double seat valve

[0002] The invention relates to a valve drive for a double-seat valve, comprising a first closing element connected to a first valve stem and a second closing element connected to a second valve stem. The first closing element is adjustable by means of the valve drive between a position cooperating with a first valve seat and a position lifted from the first valve seat. The second closing element is adjustable by means of the valve drive independently of the first closing element between a position cooperating with a second valve seat and a position lifted from the second valve seat. The invention also relates to a double-seat valve.

[0003] In double-seat valves of the type in question here, two closing elements, designed, for example, as valve disks, can be moved independently of each other in a stroke-like manner. Double-seat valves are used, for example, in process plants for the production of food, beverages, pharmaceuticals, and fine chemical products, as well as in biotechnology. Considerable pipeline diameters of 10 cm and more are used. At the same time, the process components must meet stringent hygienic and, in some cases, aseptic requirements, for example, regarding tightness and cleanability. Double-seat valves are particularly suitable for such applications.

[0004] Pneumatic valve actuators are generally used to adjust the closing elements of double-seat valves. These have a piston that is pressurized with compressed air. The piston can be spring-loaded in one direction of movement. However, there are also valve actuators in which the piston is pressurized with compressed air to move in each of its directions. Compressed air in process plants is increasingly only provided for the valves. This is costly to purchase and maintain. WO 2016 / 192967 A1 generally proposes an electric motor-driven valve actuator as an alternative to a pneumatic valve actuator. However, such valve actuators have not yet been successful in the aforementioned application areas.

[0005] Another electromotive valve drive is known from WO 2023 / 118143 A1. An actuator arrangement for a first and a second valve stem of a double-seat valve is proposed, wherein the valve stems are arranged coaxially and each is completely encompassed by an electric motor comprising a rotor and a stator. The respective valve stem and the associated rotor are connected to each other according to the principle of a recirculating ball screw. The rotors of the electric motors are designed to engage a respective threaded portion of the respective valve stem such that a rotational movement of the rotor causes a movement of the respective valve stem in the axial direction.

[0006] A disadvantage of the valve drive proposed in WO 2023 / 118143 A1 is an undesirably large axial length due to the electric motors arranged one behind the other to independently drive the coaxial valve stems. Furthermore, the electric motor drives are difficult to access or can only be accessed with considerable effort in the event of maintenance or repair. Furthermore, the solution proposed in WO 2023 / 118143 A1 requires drive components specifically designed for the respective valve, which further increases the effort and further impairs repairability.

[0007] Based on the described prior art, the invention is therefore based on the object of providing a valve actuator and a double-seat valve with which the independent adjustment of the closing elements of a double-seat valve is possible in a simpler and more cost-effective manner than the prior art, as well as with less effort, even in the event of maintenance or repair. The invention solves this problem by independent claims 1 and 15. Advantageous embodiments can be found in the dependent claims, the description, and the figures.

[0008] For a valve drive of the type mentioned above, the invention solves the problem by

[0009] • that the valve drive comprises a first electric motor with a first rotor and a first stator and first transmission means, wherein the first electric motor can be coupled to the first valve stem by the first transmission means, so that the first valve stem can be moved in the axial direction by a rotational movement of the first rotor to adjust the first closing element, and so that the first electric motor is arranged next to the first and / or the second valve stem, and

[0010] • that the valve drive has a second electric motor with a second rotor and a second stator and second transmission means, wherein the second electric motor can be coupled to the second valve stem by the second transmission means, so that the second valve stem can be moved in the axial direction by a rotational movement of the second rotor to adjust the second closing element, and so that the second electric motor is arranged next to the first and / or the second valve stem.

[0011] The valve actuator according to the invention and the double-seat valve according to the invention can be used in process plants for the production of food, beverages, medicines and fine chemical products, as well as in biotechnology. They can be used in particular in process plants that require highly hygienic and / or aseptic properties of the process components, particularly with regard to leak tightness and cleanability. The closing elements can each be designed as a valve disk. The position of the closing elements in which they interact with the respective valve seat can be a closed position. The position lifted from the respective valve seat can be an open position. In the position in which they interact with the respective valve seat, the closing elements preferably bear sealingly against the respective valve seat. For this purpose, the closing elements can have a seal. The closing elements are each connected to a valve stem.The closing elements can be integrally connected to the respective valve stem. However, they can also be formed separately and fixedly mounted thereon. The valve drive according to the invention enables the closing elements to move independently of one another. The first and second valve stems can be arranged coaxially. The second valve stem can be formed, at least in sections, as a hollow rod. The first valve stem can be arranged so that it can move axially, at least in sections, within the second valve stem, which is formed as a hollow rod.

[0012] The double-seat valve generally has at least two ports for a fluid to be passed through the valve. The ports can be selectively connected to or separated from one another by the closing elements, particularly during a so-called main stroke of the double-seat valve. During this main stroke, the first and second closing elements can each be moved into a position lifted from their respective valve seats, so that a fluid to be passed can flow past the closing elements from a first port to a second port of the valve. For example, to clean the double-seat valve, one of the closing elements can be lifted slightly from its valve seat, during a so-called lift stroke, while the other closing element remains in its position against the valve seat. In this state, for example, a cleaning fluid can be introduced to clean a valve seat.The valve drive according to the invention uses electric motor drives to independently adjust the valve stems and thus the closing elements. The movement of the valve stems by the respective electric motor can occur in at least one axial direction of the respective valve stem. In the opposite axial direction, the valve stems can be preloaded, for example, by spring means. However, it is also possible to ensure movement of the valve stems in both axial directions using the electric motors. Of course, a mixed design is also possible, in which one valve stem is moved by an electric motor in only one axial direction and the other valve stem is moved by the electric motor in both axial directions.

[0013] According to the invention, first and second transmission means are provided, by means of which the first and second electric motors are coupled to the first and second valve stems, respectively. The first and second transmission means are designed such that a movement of the first and second valve stems in the axial direction for adjusting the first and second closing elements is brought about by a rotational movement of the first and second rotors, respectively. The transmission means therefore convert the rotational movement of the rotors into a translational movement in the axial direction of the respective valve stems. The rotors form, in particular, the rotating, magnetically acting parts of the electric motors, which interact with the respective stator of the electric motor as a stationary, magnetically acting part of the electric motor. The rotors generally rotate an output shaft or motor shaft of the electric motor.The rotor can comprise the output shaft or a shaft connected to the output shaft and an armature. If the armature is not a permanent magnet, the rotor can further comprise a coil. Furthermore, the transmission means are designed such that the first or second electric motor with the first or second rotor and stator, unlike in the prior art explained above, is not arranged coaxially to the valve stems and does not encompass them, but rather next to the first and / or second valve stem. The first and second transmission means according to the invention therefore, in addition to the function of converting a rotary movement into a translatory movement, also produce a lateral deflection between the rotary movement of the respective rotor and the translatory movement of the respective valve stem, so that the electric motors can be arranged, for example, in a housing of the double-seat valve laterally next to the first and / or second valve stem.The axis of rotation of the first rotor can run parallel and spaced from the axial direction of the first and / or second valve stem, and / or the axis of rotation of the second rotor can run parallel and spaced from the axial direction of the first and / or second valve stem. The inventive arrangement of the first and second electric motors next to the first and / or second valve stem means that the first electric motor and / or the second electric motor can be arranged laterally offset along the longitudinal extent of the first and / or second valve stem, or that the first electric motor and / or the second electric motor can be arranged next to the first and / or second valve stem outside the longitudinal extent of the first and / or second valve stem, for example above an upper end or below a lower end of the first and / or second valve stem.

[0014] Due to the inventive design with the first and second transmission means, the entire drive unit can be made considerably shorter than in the prior art. Thus, the first and second electric motors do not have to be arranged coaxially with the valve stems, one behind the other, but can, for example, be positioned on opposite sides of one of the valve stems at a similar or substantially the same height. Due to the arrangement of the electric motors next to the first and / or second valve stems and thus not coaxial with the valve stems, no complex, specially designed electromotive drive components are required. Instead, inexpensive and readily available standard components for the drive train can be used and combined in a modular manner, for example in a housing of the double-seat valve, next to the first and / or second valve stem.In addition to the components of the electric motor, this also applies in particular to any transmission and brake that may be provided. The valve drive according to the invention is therefore particularly easy to repair. In the event of maintenance or repair, the drive train components are also easier and faster to access than in the prior art. This is also facilitated by the modular design of the valve drive.

[0015] According to one embodiment, it can be provided that the first transmission means comprise a threaded spindle that rotates due to a rotational movement of the first rotor, and that the first transmission means comprise a spindle nut that engages around the thread of the threaded spindle from the outside and interacts with the first valve stem, wherein the threaded spindle is fixed in the axial direction and the spindle nut is arranged in a rotationally fixed manner such that the spindle nut can be moved in the axial direction by rotation of the threaded spindle, so that the first valve stem is also moved in the axial direction to adjust the first closing element. In this embodiment, the conversion of the rotational movement of the first rotor into a translational axial movement of the first valve stem takes place by a spindle screw drive, in particular a ball screw drive. The spindle nut can be connected to the first valve stem detachably or permanently, directly or indirectly.It can also rest against the first valve stem without being attached to it. The aforementioned design offers a particularly reliable and robust conversion of the rotary motion into translational motion.

[0016] The threaded spindle is fixed in the axial direction for the function of the spindle screw drive, whereby the fixation can be achieved by a floating bearing. For example, the threaded spindle can be mounted in the axial direction against at least one spring, for example at least one disc spring. This allows a slight axial movement of the threaded spindle against the force of the spring. As a result, the force with which a seal usually provided on the closing element and / or the valve seat is pressed is defined by the spring travel of the spring. The electric motor can be switched off when the end position in which the first closing element is in contact with the valve seat is reached, for example, via the current increase of the electric motor. If this increase is linear in the range of the spring stroke and not abrupt, as is the case when such a spring is omitted, the switch-off occurs at a defined contact force.This increases the service life of the seal.

[0017] According to a further embodiment, the first transmission means may further comprise a spur gear driven by the first rotor, which directly or indirectly engages the threaded spindle to transmit the rotational movement of the first rotor to the threaded spindle. The spur gear is directly or indirectly connected to an output shaft of the first electric motor and is rotated by the rotation of the first rotor. The spur gear may be arranged coaxially with the first rotor.

[0018] According to a further related embodiment, the first transmission means can further comprise a gearwheel connected to the threaded spindle in a rotationally fixed manner, wherein the spur gear engages with an external toothing of the gearwheel. The spur gear engages with the gearwheel such that rotation of the spur gear causes rotation of the gearwheel and the threaded spindle connected to it in a rotationally fixed manner. The gearwheel can be formed integrally with the threaded spindle or can be separately attached to it in a rotationally fixed manner. The gearwheel is arranged coaxially to the threaded spindle. The aforementioned embodiment realizes a lateral offset between the electric motor and the threaded spindle in a particularly simple and reliable manner. According to a further embodiment, the threaded spindle can have engagement means for manually rotating the threaded spindle on an end face facing away from the first valve stem.This represents a further advantage over the embodiment of WO 2023 / 118143 A1. Due to the inventive arrangement of the drive components, the end of the threaded spindle facing away from the first valve stem can be easily accessed from the outside. Thus, the threaded spindle can be easily rotated manually using a tool engaging the engagement means, which can be guided, for example, through a corresponding housing opening in a housing of the double-seat valve. In this way, the first closing element can be easily opened or closed manually, for example in the event of a malfunction. The engagement means for manually rotating the threaded spindle can, for example, comprise a polygon socket, in particular a hexagon socket. The threaded spindle can then be manually rotated using a standard tool.

[0019] According to a further embodiment, it can be provided that, in order to open the double-seat valve, the first closing element and the second closing element can be moved jointly by the first electric motor into the position lifted away from the respective first or second valve seat, that the first closing element can be moved independently of the second closing element into a cleaning position lifted away from the first valve seat by the first electric motor, and that the second closing element can be moved independently of the first closing element into a cleaning position lifted away from the second valve seat by the second electric motor.

[0020] The first closing element can be moved into the cleaning position in a direction opposite to the direction of movement into the position lifted from the first valve seat, for example in the case of a valve with a radial seal between the first closing element and the first valve seat. However, it is also possible for the first closing element to be moved into the cleaning position in the direction of movement into the position lifted from the first valve seat, for example in the case of a valve with an axial seal between the first closing element and the first valve seat. The second closing element can also be moved into the cleaning position in the direction of movement into the position lifted from the second valve seat.However, it would also be conceivable in principle that the movement of the second closing element into the cleaning position takes place in a direction opposite to the direction of movement for moving into the position lifted from the second valve seat.

[0021] In the embodiment explained above, it is possible to open the double-seat valve during a main stroke by lifting the first and second closing elements from the first and second valve seats, respectively, by actuating the first electric motor alone. Starting from the position of the first and second closing elements in which they interact with the first and second valve seats, i.e. when the double-seat valve is closed, the first closing element can entrain the second closing element during the main stroke, for example by means of associated stop surfaces of the first and second closing elements, so that both closing elements, driven by the first electric motor, are lifted from their respective valve seats in a common direction of movement. A flow of a fluid, in particular a liquid, through the valve, for example, past the lifted closing elements, is then possible.To close the valve, the first and second closing elements can be moved together, for example, into their respective valve seat positions. This movement can be effected by the first and / or second electric motor. Thus, the valve can be opened and closed easily with just one electric motor. In the embodiment of WO 2023 / 118143 A1, however, two motors are required, which must be operated simultaneously.

[0022] At the same time, the first and second closing elements can be moved by the first and second electric motors, respectively, independently of the other closing element, into a cleaning position lifted from their respective valve seat within the framework of a so-called lift stroke. In the cleaning position, cleaning of the first and second closing elements and / or the first and second valve seats is possible in a manner known per se, for example by introducing a cleaning fluid, in particular a cleaning liquid. The lift stroke of the second closing element occurs in the same direction of movement as the main stroke. The lift stroke of the first closing element, in contrast, occurs in a direction opposite to the main stroke. The return movement of the first closing element from the cleaning position into the position interacting with the first valve seat can again be carried out by the first electric motor.Accordingly, the return movement of the second closing element from the cleaning position to the position interacting with the second valve seat can again be accomplished by the second electric motor. This allows for particularly flexible opening and closing of the valve, as well as cleaning of the valve seats and closing elements.

[0023] According to a further embodiment, the second transmission means can comprise a cam disc that can be brought into engagement directly or indirectly with the second valve stem. The cam disc can be moved in the axial direction by a rotational movement of the second rotor, so that the second valve stem is also moved in the axial direction to adjust the second closing element. The rotational movement of the second rotor is thus converted into a translational movement of the cam disc in the axial direction of the second valve stem. By engaging the cam disc with the second valve stem, this translational movement of the cam disc is converted into a corresponding translational movement of the second valve stem.

[0024] According to a further embodiment, the lifting disc can have a central bore with an inwardly projecting shoulder, with which a shoulder of a driver sleeve connected to the second valve stem can be brought into positive engagement in a first axial direction. The inwardly projecting shoulder can be formed, for example, at one end, for example at a lower end, of the lifting disc. The driver sleeve can be integrally connected to the second valve stem. It can also be formed separately from it and fastened to it. It is possible for the positive connection achieved by the shoulders to exist only in one axial direction. It is also possible for the positive connection to exist in the first axial direction and an opposite second axial direction. In particular, if the positive connection exists only in the first axial direction, the driver sleeve can be preloaded by spring means in a second axial direction opposite the first axial direction.The second closing element can be supported by the first valve stem via the spring means. The lifting disc and the driver sleeve or shoulder are then decoupled, so that the second valve stem moves independently of the lifting disc during the main stroke, particularly when the lifting disc is in its lower position. In contrast to the solution explained above in WO 2023 / 118143 A1, this design eliminates the need for mechanically independent movement of both closing elements. This eliminates the need, compared to the prior art, to control both motors in a complex, synchronized manner during the main stroke so that the closing elements remain in contact. This control-related challenge is eliminated with the aforementioned design. The spring means can comprise a spring, for example a coil spring.With this design, the driver sleeve can be moved in the first axial direction against the spring preload of the spring means. The spring means return the driver sleeve to its original position when the positive locking action no longer exists. The cam disc and driver sleeve are therefore not rigidly connected. This allows for even greater variability when adjusting the double-seat valve, for example, spreading, in which the two closing elements are slightly separated from each other in their respective open positions, namely, spread apart.

[0025] According to a further embodiment, it can be provided that the second transmission means further comprise a bushing with an internal thread that is driven in rotation by rotation of the second rotor, and that the lifting disc is arranged in a rotationally fixed and axially movable manner within the bushing and has an external thread that engages with the internal thread of the bushing, so that the lifting disc can be moved in the axial direction by rotation of the bushing. The rotationally fixed arrangement of the lifting disc can be ensured by an anti-twist device. For example, a rod arranged in a housing of the valve can engage in a recess in the lifting disc and thus prevent rotation of the lifting disc.As explained above, the movement of the cam disc in the axial direction, caused by a rotation of the bushing and the corresponding running of the cam disc with its external thread in the internal thread of the bushing, also moves the second valve stem and with it the second closing element in this axial direction.

[0026] The second transmission means can further comprise a gear driven by the second rotor, which engages with an internal toothing of the bushing to transmit the rotational movement of the second rotor to the bushing. The gear is directly or indirectly connected to an output shaft of the second electric motor and is rotated by rotation of the second rotor. The gear can be arranged coaxially to the second rotor. The external thread of the gear has, in particular, a smaller diameter than the internal thread of the bushing. In this way, a lateral offset between the axis of rotation of the second rotor and the longitudinal axis of the second valve stem is realized in a robust and permissible manner.

[0027] Furthermore, position detection means, for example, a positioning rod connected to the driver sleeve, can be provided, with which the axial position of the driver sleeve and thus of the second closing element can be detected. For example, a positioning rod can interact, for example, on its side facing away from the driver sleeve, with a sensor for detecting the axial position of the positioning rod.

[0028] According to a further embodiment, the second transmission means can further comprise at least one screw drive, in particular a ball screw drive, arranged non-coaxially with the lifting disc, which converts a rotational movement of the second rotor into an axial movement of the lifting disc. Several such screw drives, which are not arranged centrally, can also be provided to move the lifting disc axially.

[0029] According to a further embodiment, it can be provided that the first transmission means comprise a gear arranged between the first electric motor and the first valve stem and / or a brake arranged between the first electric motor and the first valve stem and / or that the second transmission means comprise a gear arranged between the second electric motor and the second valve stem and / or a brake arranged between the second electric motor and the second valve stem. A brake is not required if the screw drive preferably formed by the first or second transmission means is self-locking, i.e. the threaded spindle or the bushing does not rotate when an axial force is exerted on the threaded nut or the lifting disk. In order toTo hold the closing elements in the closed position interacting with the respective valve seat, a defined minimum force must be exerted on the respective valve stem. In the direct drive described in WO 2023 / 118143 A1, this force must be generated 1:1 by a corresponding torque of the electric motor, which requires an electric motor specifically adapted for the intended application, particularly at low speeds. In the aforementioned embodiment of the present invention with a gear arranged between the electric motor and the valve stem, the electric motor can, however, be operated at a significantly higher speed and considerably lower torque, since this torque is amplified by the gear, for example by a factor of at least 50, preferably at least 100.The torque required to generate the minimum force on the valve stem can be achieved flexibly and with standard components through a combination of engine speed / torque and gear ratio, whereas the described state of the art does not allow for this degree of freedom. Thus, the use of a gearbox has a beneficial effect on the motor selection. Sufficient torque must be applied to overcome the actuating forces. The use of a gearbox advantageously allows a smaller electric motor to suffice for this purpose.

[0030] The invention also achieves the object by means of a double-seat valve, comprising a first closing element connected to a first valve stem of the double-seat valve and a second closing element connected to a second valve stem of the double-seat valve, and comprising a valve drive according to the invention, wherein the first closing element of the valve drive is adjustable between a position in which it cooperates with a first valve seat and a position lifted away from the first valve seat, and wherein the second closing element is adjustable by means of the valve drive independently of the first closing element between a position in which it cooperates with a second valve seat and a position lifted away from the second valve seat. The first or second electric motor is coupled to the first or second valve stem by the first or second transmission means such that the first or second valve stem is used to adjust the first or second valve seat.second closing element is movable in the axial direction by a rotational movement of the first or second rotor, and the first or second electric motor is arranged next to the first and / or the second valve stem.

[0031] The rotational axis of the first rotor can, in particular, run parallel and spaced from the axial direction of the first and / or second valve stem. The rotational axis of the second rotor can also run parallel and spaced from the axial direction of the first and / or second valve stem.

[0032] According to a further embodiment, the first valve stem can be mounted in the axial direction in the closed position against at least one spring, for example at least one disc spring. In this embodiment, the axial fixation of the mounting of the first valve stem is therefore achieved by means of one or more springs. This allows a slight axial movement of the first valve stem against the force of the spring. As a result, the force with which a seal usually provided on the closing element and / or the valve seat is pressed is defined by the spring travel of the spring. The electric motor can be switched off when the end position in which the first closing element is in contact with the valve seat is reached, for example, via the current increase of the electric motor. If this increase occurs linearly in the range of the spring stroke and not abruptly, as is the case when such a spring is omitted, switching off occurs at a defined contact force.This increases the service life of the seal.

[0033] An embodiment of the invention is explained in more detail below with reference to the figures. They show schematically:

[0034] Figure 1 shows a double seat valve according to the invention with a valve drive according to the invention in a sectional view, and Figure 2 shows the double seat valve from Figure 1 in a sectional view rotated by 90° compared to Figure 1.

[0035] Unless otherwise stated, the same reference symbols in the figures refer to the same objects.

[0036] The double-seat valve according to the invention is used to guide a fluid, in particular a liquid. For this purpose, the double-seat valve has a first connection 10 and a second connection 12 for connection to corresponding fluid lines. Between the connections 10, 12, a passage 14 is provided which, as explained below, can be selectively closed or opened by closing elements of the double-seat valve. In the example shown, the double-seat valve has a first valve stem 16 formed from several sections, to which a first closing element 18 is connected. Furthermore, the double-seat valve has a second valve stem 20, to which a second closing element 22 is connected. The closing elements 18, 22 are each designed as valve disks and have on their outer side an annular circumferential seal 24, 26, with which they are sealingly held against a first valve seat 28 or a second valve seat 29 in the closed position shown in the figures.a second valve seat 30 and thus close the passage 14. The second valve stem 20 is designed as a hollow rod and accommodates the first valve stem 16 coaxially and axially movably.

[0037] By means of the valve drive explained in more detail below, the first valve stem 16 and the second valve stem 20, and with them the first closing element 18 and the second closing element 22, can be moved independently of one another in the axial direction. To open the passage 14, the first valve stem 16 can be moved axially upward in the figures, with the first closing element 18 being received in an annular recess 32 in the second closing element 22. Subsequently, the first and second closing elements 18, 22 can be moved further axially upward together with the first and second valve stems 16, 20 in a main stroke to open the passage 14.For cleaning purposes, for example, it is possible, by means of the valve drive according to the invention explained below, to move the second valve stem 20 and with it the second closing element 22 slightly upwards from the position shown in the figures during a lift stroke, so that the second valve seat 30 and the seal 26 are exposed. Correspondingly, it is possible to move the first valve stem 16 and with it the first closing element 18 slightly axially downwards from the closed position shown in the figures, so that the first valve seat 28 and the seal 24 are exposed. Furthermore, the valve drive according to the invention also makes it possible to spread the closing elements 18, 22 in the open position, i.e. to slightly move the closing elements 18, 22 away from one another.

[0038] The double-seat valve has a housing 34 composed of several sections, in which the valve drive according to the invention is arranged. The valve drive comprises a first electric motor 36 arranged laterally next to the first valve stem 16, having a first rotor and a first stator. The axis of rotation of the first rotor is spaced parallel to the longitudinal axis of the first valve stem 16. An output shaft driven by the rotor is connected via a brake 38 and a gear 40 to a spur gear 42 arranged coaxially to the first rotor, which is also driven in rotation by rotation of the first rotor. The spur gear 42 engages with external teeth of a gear 44 arranged coaxially to the first valve stem 16, so that this gear is also rotated when the spur gear 42 rotates.The gear 44 is non-rotatably connected to a threaded spindle 46, which is rotatable and axially fixed in the housing 34 and is also arranged coaxially to the first valve stem 16. In the example shown, the gear 44 and, with it, the threaded spindle 46, are mounted in an axially floating manner against disc springs 74. This serves to reposition or relieve the first closing element 18, which is particularly advantageous for axially sealing valves, and also leads to a reduction in the load on the seal 24, as explained above. In radially sealing valves, the disc springs 74 are particularly advantageous in the event of pressure surges and end stops, and thus to protection against wear and / or damage. A spindle nut 48 engages the thread of the threaded spindle 46 from the outside and is mounted coaxially to the threaded spindle 46 in the housing 34, non-rotatably. Furthermore, the spindle nut 48 is connected to the first valve stem 16, for example, by screwing.A rotary movement transmitted to the threaded spindle 46 by the first rotor of the first electric motor 36 and via the spur gear 42 and the gear 44 thus leads to a translational movement of the spindle nut 48 in the axial direction and correspondingly to a translational movement in the axial direction of the first valve stem 16 and the first closing element 18.

[0039] In the example shown, the threaded spindle 46 also has engagement means 50, for example a hexagon socket, on an end face facing away from the first valve stem 16, which is the upper end face in the figures. By engaging with a suitable tool, it is thus possible to manually rotate the threaded spindle 46 to manually move the first closing element 18.

[0040] Also arranged in the housing 34 is a second electric motor 52 having a second rotor and a second stator, which, like the first electric motor 36, is positioned laterally next to the first valve stem 16 in the housing 34. As with the first electric motor 36, the axis of rotation of the second rotor of the second electric motor 52 is arranged parallel and spaced from the longitudinal axis of the first valve stem 16 and thus also from the longitudinal axis of the second valve stem 20, which is arranged coaxially to the first valve stem 16. An output shaft of the second rotor is connected via a gear 54 to a gear 56, which is also rotated accordingly when the second rotor rotates. The gear 56 engages with its external toothing into an internal toothing 58 of a bushing 60, which is arranged coaxially to the second valve stem 20 and is rotatable in the housing 34. The bushing 60 is thus also rotated when the second rotor rotates.The bushing 60 has a helical internal thread 62 into which a lifting disc 64 arranged within the bushing 60 engages with a corresponding external thread. The lifting disc 64 is arranged within the bushing 60 in a rotationally fixed manner via a rod 67 guided through a recess in the lifting disc 64 as an anti-twist device. Rotation of the bushing 60 accordingly leads to a translational movement of the lifting disc 64 in the axial direction. The lifting disc 64 comprises a central bore, at the lower end of which a shoulder 66 is formed. A driver sleeve 68, which is firmly connected to the second valve stem 20, also has a shoulder 70 at its upper end. The shoulders 66, 70 can be brought into positive engagement with one another by moving the lifting disc 64 upwards in the axial direction in the figures.By further moving the lifting disc 64 in this axial direction, i.e. upwards in the figures, the driver sleeve 66 is also moved upwards against the spring preload of a helical spring 72, so that the second valve stem 20 and the second closing element 22 are moved upwards with it. The second closing element is supported by the first valve stem 16 via the helical spring 72. The lifting disc 64 and the driver sleeve 66 or the shoulder 70 are decoupled, so that the second valve stem 20 moves independently of the lifting disc 64 during the main stroke, particularly when the lifting disc 64 is in its lower position.

[0041] Figure 2 also shows a positioning rod 76 connected to the driver sleeve 68, which, for example, interacts on its side facing away from the driver sleeve 68 with a sensor system for detecting the axial position of the positioning rod 76. In this way, the axial position of the driver sleeve 68 and thus of the second closing element 22 can be detected.

[0042] If the lifting disc 64 is subsequently moved in the opposite axial direction, the driver sleeve 68 and with it the second valve stem 20 and the second closing element 22 return to their starting position due to the spring preload of the helical spring 72.

[0043] By arranging the drive components, in particular the first and second electric motors 36, 52, laterally next to the first valve stem 16, easy access for maintenance or repair can be ensured through a corresponding access opening in the housing 34. On the other hand, the overall height of the double-seat valve is reduced. Furthermore, this arrangement makes it possible to use standard components for the drive components, further reducing the complexity. The accessibility of the threaded spindle 46 allows, as explained above, manual actuation of the double-seat valve, for example, in the event of a fault condition.

[0044] List of reference symbols

[0045] 10 Connection

[0046] 12 connection

[0047] 14 passage

[0048] 16 First valve stem

[0049] 18 First locking element

[0050] 20 Second valve stem

[0051] 22 Second locking element

[0052] 24 Seal

[0053] 26 Seal

[0054] 28 First valve seat

[0055] 30 Second valve seat

[0056] 32 recess

[0057] 34 housings

[0058] 36 First electric motor

[0059] 38 Brake

[0060] 40 gearboxes

[0061] 42 Spur gear

[0062] 44 gear

[0063] 46 threaded spindle

[0064] 48 spindle nut

[0065] 50 interventional devices

[0066] 52 Second electric motor

[0067] 54 gearboxes

[0068] 56 gear

[0069] 58 internal gearing

[0070] 60 socket

[0071] 62 internal thread

[0072] 64 lifting disc

[0073] 66 paragraph

[0074] 67 rod

[0075] 68 Driving sleeve

[0076] 70 paragraph

[0077] 72 coil spring

[0078] 74 disc springs

[0079] 76 Position rod

Claims

Claims 1. Valve drive for a double-seat valve, comprising a first closing element (18) connected to a first valve stem (16) and a second closing element (22) connected to a second valve stem (20), wherein the first closing element (18) is adjustable by means of the valve drive between a position cooperating with a first valve seat (28) and a position lifted from the first valve seat (28), and wherein the second closing element (22) is adjustable by means of the valve drive independently of the first closing element (18) between a position cooperating with a second valve seat (30) and a position lifted from the second valve seat (30), characterized in that • that the valve drive comprises a first electric motor (36) with a first rotor and a first stator and first transmission means, wherein the first electric motor (36) can be coupled to the first valve stem (16) by the first transmission means, so that the first valve stem (16) can be moved in the axial direction by a rotational movement of the first rotor to adjust the first closing element (18), and so that the first electric motor (36) is arranged next to the first and / or the second valve stem (16, 20), and • that the valve drive has a second electric motor (52) with a second rotor and a second stator and second transmission means, wherein the second electric motor (52) can be coupled to the second valve stem (20) by the second transmission means, so that the second valve stem (20) can be moved in the axial direction by a rotary movement of the second rotor to adjust the second closing element (22), and so that the second electric motor (52) is arranged next to the first and / or the second valve stem (16, 20).

2. Valve drive according to claim 1, characterized in that the first transmission means have a threaded spindle (46) which is driven in rotation by a rotational movement of the first rotor, and in that the first transmission means have a spindle nut (48) which engages around the thread of the threaded spindle (46) from the outside and interacts with the first valve stem (16), wherein the threaded spindle (46) is fixed in the axial direction and the spindle nut is arranged in a rotationally fixed manner such that the spindle nut (48) can be moved in the axial direction by a rotation of the threaded spindle (46), so that the first valve stem (16) is also moved in the axial direction to adjust the first closing element (18).

3. Valve drive according to claim 2, characterized in that the threaded spindle (46) is mounted in the axial direction against at least one spring (74).

4. Valve drive according to one of claims 2 or 3, characterized in that the first transmission means further comprise a spur gear (42) driven by the first rotor, which is directly or indirectly in engagement with the threaded spindle (46) for transmitting the rotary movement of the first rotor to the threaded spindle (46).

5. Valve drive according to claim 4, characterized in that the first transmission means further comprise a gear (44) connected in a rotationally fixed manner to the threaded spindle (46), wherein the spur gear (42) is in engagement with an external toothing of the gear (44).

6. Valve drive according to one of claims 3 to 5, characterized in that the threaded spindle (46) has engagement means (50) for manually rotating the threaded spindle (46) on an end face facing away from the first valve stem (16).

7. Valve drive according to one of the preceding claims, characterized in that, in order to open the double-seat valve, the first closing element (18) and the second closing element (22) can be moved jointly by the first electric motor (36) into the position lifted away from the respective first or second valve seat (28, 30), in that the first closing element (18) can be moved independently of the second closing element (22) into a cleaning position lifted away from the first valve seat (28) by the first electric motor (36), and in that the second closing element (22) can be moved independently of the first closing element (18) into a cleaning position lifted away from the second valve seat (30) by the second electric motor (52).

8. Valve drive according to one of the preceding claims, characterized in that the second transmission means have a lifting disc (64) which can be brought into engagement directly or indirectly with the second valve stem (20), wherein the lifting disc (64) is movable in the axial direction by a rotational movement of the second rotor, so that the second valve stem (20) is also moved in the axial direction to adjust the second closing element (22).

9. Valve drive according to claim 8, characterized in that the lifting disc (64) has a central bore with an inwardly projecting shoulder (66) with which a shoulder (70) of a valve stem (20) connected driver sleeve (68) can be brought into positive engagement in a first axial direction.

10. Valve drive according to claim 9, characterized in that the driver sleeve (68) is prestressed by spring means (72) in a second axial direction opposite to the first axial direction, wherein the second closing element (22) is preferably supported by the first valve stem 16 via the spring means (72).

11. Valve drive according to one of claims 8 to 10, characterized in that the second transmission means further comprise a bushing (60) with an internal thread (62) which is driven in rotation by a rotation of the second rotor, and in that the lifting disc (64) is arranged in a rotationally fixed and axially movable manner within the bushing (60) and has an external thread which engages with the internal thread (62) of the bushing (60), so that the lifting disc (64) can be moved in the axial direction by a rotation of the bushing (60).

12. Valve drive according to claim 11, characterized in that the second transmission means further comprise a gear (56) driven by the second rotor, which engages in an internal toothing (58) of the bushing (60) for transmitting the rotary movement of the second rotor to the bushing (60).

13. Valve drive according to one of claims 8 to 10, characterized in that the second transmission means further comprise at least one screw drive arranged non-coaxially to the lifting disc (64), which converts a rotational movement of the second rotor into an axial movement of the lifting disc (64).

14. Valve drive according to one of the preceding claims, characterized in that the first transmission means comprise a gear (40) arranged between the first electric motor (36) and the first valve stem (16) and / or a brake (38) arranged between the first electric motor (36) and the first valve stem (16) and / or that the second transmission means comprise a gear (54) arranged between the second electric motor (52) and the second valve stem (20) and / or a brake arranged between the second electric motor (52) and the second valve stem (20).

15. A double-seat valve, comprising a first closing element (18) connected to a first valve stem (16) of the double-seat valve and a second closing element (22) connected to a second valve stem (20) of the double-seat valve, and comprising a valve drive according to one of the preceding claims, wherein the first closing element (18) is adjustable by means of the valve drive between a position cooperating with a first valve seat (28) and a position lifted away from the first valve seat (28), and wherein the second closing element (22) is adjustable by means of the valve drive independently of the first closing element (18) between a position cooperating with a second valve seat (30) and a position lifted away from the second valve seat (30).

16. Double seat valve according to claim 15, characterized in that the axis of rotation of the first rotor runs parallel and spaced from the axial direction of the first and / or second valve stem (16, 20) and / or that the axis of rotation of the second rotor runs parallel and spaced from the axial direction of the first and / or second valve stem (16, 20).

Images