Globe valve with stroke actuator

Description

[0001] The invention relates to a globe valve with a globe drive according to the preamble of the first claim.

[0002] Globe valves with actuators are used in plants for the production of food, beverages, pharmaceuticals and fine chemical products as well as in biotechnology.

[0003] There are various ways to integrate the globe valve into the process plant for the aforementioned applications. So-called control heads can be used. These then control the stroke drive, for example, by switching compressed air with so-called pilot valves. The plant control system simply sends commands to this control head. WO 2002 / 093058 A1 shows one such example.

[0004] However, globe valves can also be integrated into the process plant in a simpler way without the need for a control head.

[0005] A rod section connected to a valve stem of the globe valve extends from the actuator. A sensor is mounted on this rod section, which triggers a measuring sensor. Two measuring sensors are provided to determine the two positions of the rod section, which correspond, for example, to the open and closed positions of the globe valve. The actuator is controlled, for example, with compressed air, via a correspondingly designed device in the process plant.

[0006] When using a control head, the sensors are often located inside the control head. This provides mechanical protection. With the simpler solution, there is a risk of the sensors becoming misaligned. In the worst case, this could even result in a part of the sensor shearing off. Furthermore, with this arrangement, it is important to prevent any body part, such as a finger, of the operating personnel or objects from getting between the transmitter and the sensor.

[0007] These risks have previously been eliminated by additional components, such as an additional cylinder that at least surrounds the rod. However, additional components also require additional installation space.

[0008] A lift valve with a measuring device for detecting the position of a lift rod is known, for example, from GB 2194648 A.

[0009] US 2005 / 127200 A1 relates to a valve system comprising a valve assembly, an actuator for actuating the valve assembly, and a valve position sensing unit for monitoring the position of the valve assembly. The actuator has a housing and a shaft extending through the housing. The valve position sensing unit includes a sensor with a range of motion extending into the actuator housing. This is intended to result in a low-profile valve system.

[0010] WO 2016 / 146632 A1 relates to a globe valve comprising a closing body, a lifting drive, a valve rod connected to the closing body, an actuator rod connected to the valve rod, and a rotary decoupling device provided between the valve rod and the actuator rod. The rotary decoupling device comprises at least two shell segments, and the actuator rod comprises a coupling element. The shell segments form a positive connection with the valve rod in the direction of the lifting movement and a positive connection with the coupling element in the direction of the lifting movement. The rotary decoupling device is intended to be suitable for absorbing large axial loads.

[0011] US 2015 / 075651 A1 relates to a device comprising a spindle and at least one switching target assembly consisting of a switching target and a target ring. The target ring has an opening having an inner diameter that is smaller than the outer diameter of an outer surface of the spindle. When the at least one switching target assembly is installed over the spindle, interference causes at least a portion of the target ring to deflect into at least one groove / space of a surface finish of the spindle to energize the target ring to encompass the surface finish of the spindle to secure the switching target when the spindle moves. This is intended to ensure that the activated target ring has a higher coefficient of static friction while still allowing the position of the switch target assembly to be reconfigured as needed.

[0012] It was therefore an object of the invention to create an improved globe valve with a measuring device that is compact and safe.

[0013] This problem is solved by a globe valve according to the first claim. The dependent claims specify advantageous developments.

[0014] The claimed device is based on a lift valve with a valve housing and a lift drive, which comprises an actuating rod movable along a lifting axis into a first and a second end position, and a measuring device coupled to the lift drive on a side of the lift drive facing away from the valve housing, which measuring device comprises a first measuring sensor and a second measuring sensor, and with a first transmitter, which is arranged following the movement of the actuating rod, wherein the first transmitter is arranged on a sensor rod arranged in an end region of the actuating rod.

[0015] An improvement now lies in the provision of a second sensor, which follows the movement of the actuator rod, and the first measuring sensor is arranged between the second measuring sensor and the lifting drive. The first measuring sensor is excited by the second sensor, which is arranged on a side of the first sensor facing the actuator rod, when the actuator rod is in the second end position. Various operating principles for measuring sensors and sensors are known in the prior art, for example mechanical switches. Choosing a non-contact measuring principle is less prone to errors. It is cost-effective to design the measuring sensors as proximity sensors that respond to metallic sensors.

[0016] With the design presented here in claim 1, the sensor located closer to the linear actuator responds to a transmitter when the actuator rod is displaced furthest toward the sensor. This reversal of the measuring principle makes it possible to immerse one of the sensors into the linear actuator, at least into a coupling area between the linear actuator and the measuring device, and to arrange the sensors with less than the full stroke distance. The design according to claim 1 enables a significantly more compact and reliable arrangement with the linear valve, linear actuator, and measuring device. The more compact arrangement provides security against mechanical interference and the introduction of interfering particles into the measuring device.

[0017] In a first refinement, the susceptibility to interference caused by objects between the sensor and the transmitter is further improved by having flush surfaces on the sensor rod, the first transmitter, and the second transmitter. In this application, the flush surfaces act like a continuous, smooth cylindrical surface. In particular, this prevents a sensor from being sheared off by a transmitter or a particle moved by a transmitter.

[0018] Mechanical stability and thus safety can be increased in a further development by designing the first sensor as a single piece with the sensor rod. This advantage is further enhanced if, alternatively or additionally, the second sensor is designed as a single piece with the drive rod. The single-piece design can be so extensive that the sensor is inconspicuous, for example, merely a ledge or step.

[0019] According to a further development, the entry of objects or particles into the measuring device is reduced by closing the measuring device with a cover on the end face facing away from the lifting drive. This can be a flat cover or a dome-shaped, hood-like structure. A rounded design is more hygienic, as it reduces corners and kinks that are susceptible to contamination.

[0020] The design with a cover can be further improved by accommodating the sensor rod in a movable and sealed manner within the cover, providing an air connection, and forming an air duct in the sensor rod. For pressure-medium-operated linear actuators, whose pressure medium is supplied via the actuator rod, the design according to this refinement offers a compact and reliable pressure medium supply design.

[0021] A particularly compact design is achieved according to a further development in that the lifting drive and the measuring device are connected to one another in a coupling area and the second sensor is located in the first end position at the level of the coupling area.

[0022] Safety is increased by reducing the entry of particles into the measuring device and in particular into the space between the measuring sensors and transmitters, as the measuring device comprises a hollow rod that completely encloses the sensor rod.

[0023] Safe and reliable operation of the measuring system also depends on the precise adjustment of the sensors, ensuring that they are reliably activated by a sensor at the correct time. This is achieved according to the new design by accommodating the first sensor in a first slotted hole and the second sensor in a second slotted hole.

[0024] The globe valve is made cost-effective by simplified assembly, as the actuator rod can be coupled to a valve rod of the globe valve.

[0025] Further simplifications in assembly are achieved if the actuator rod can be connected to the sensor rod, in particular by means of a screw connection.

[0026] The invention will be explained and its advantages further illustrated using an exemplary embodiment. The figures show: Fig. 1: Section through a globe valve with a lifting drive and measuring device in a schematic representation; Fig. 2: Section along the lifting axis through the lifting drive and the measuring device, with the lifting drive in a first end position; Fig. 3: Section along the lifting axis through the lifting drive and the measuring device, with the lifting drive in a second end position.

[0027] In Fig. 1A globe valve is shown in a partially sectioned view.

[0028] The globe valve has a valve housing 1 with an interior space 2 designed to accommodate fluid. A first port 3 and a second port 4 are provided on the valve housing 1 and are fluidly connected to each other through the interior space 2. The fluid connection is switchable. For this purpose, a closing body 5 is provided, which is adjustable along a stroke axis A. The closing body 5 can be brought into sealing contact with a valve seat 6 provided on the valve housing 1.

[0029] When the closing body 5 and the valve seat 6 are in sealing contact, the fluid connection between the first connection 3 and the second connection 4 is interrupted.

[0030] The closing body 5 is located on a valve rod 7 and can be designed as a single piece. The valve rod 7 extends through a seal 8 provided in the valve housing 1, which can be designed as a combined bearing and seal, and thus protrudes from the valve housing 1.

[0031] A lantern 9 can be detachably attached to the valve housing 1. For this detachable connection, the lantern 9 can have a lantern flange 10, which can be brought into contact with a housing flange 11. The flanges 9 and 10 can be detachably connected to each other with a clamp 12, both force-fitting and positively locking.

[0032] A lifting drive 13 is connected to the lantern 9, which can also be coupled directly to the valve housing 1 without the need for a lantern. The lifting drive 13 and the lantern 9 are connected to each other by a first coupling 14. Preferably, the first coupling 14 is detachable, for example, in the form of a clamped flange connection, as described with reference to the lantern 9 and the valve housing 1.

[0033] A measuring device 15 is arranged on a side of the lifting drive opposite the valve housing 1. The lifting drive 13 and the measuring device 15 are preferably detachably coupled to one another. The connection is achieved by a second coupling 16. This second coupling 16 can be designed as a clamp flange connection, screw connection, or similar. The second coupling 16 forms a spatial part, referred to here as the coupling area.

[0034] The measuring device 15 comprises a first sensor 17 and a second sensor 18. The second sensor 18 is arranged on a side of the first sensor 17 facing away from the lifting drive 13. A first measuring line 19 connects the first sensor 17 to a device of a process plant. A second measuring line 20 connects the second sensor 18 to a device of the process plant.

[0035] Lifting drive 13 and measuring device 15 are in Fig. 2 and Fig. 3 shown in section along the stroke axis A.

[0036] The lifting drive 13 is designed to be operated by pressure medium and comprises a piston 21 that is movable along the lifting axis A and interacts with a drive rod 22, in particular driving the latter during its movement. The drive rod 22 can be connected to the valve rod 7 in a manner suitable for transmitting force in the direction of the lifting axis A. Screw connections and couplings made of half shells are known for this purpose.

[0037] The piston 21 can be preloaded in one of its directions of movement along the stroke axis H by a spring 23 or a spring assembly. Alternatively or additionally, both sides of the piston 21 can be designed to be pressurized with pressure medium.

[0038] The movement of the piston 21 in the direction of the spring 23 is limited by a stop 24 provided on the housing side. This determines the position of the piston 21 in the Fig. 3 The second end position E2 of the actuator rod 22 is determined as shown in Fig. 2The position of the piston shown corresponds to the first end position E1 of the actuator rod 22. The piston 21 is located at one end of the stroke, which is on a side of the stroke drive 13 facing the valve housing 1. In the example shown, this is the closed position of the valve. A stop can also be provided for this first end position E1, for example, if a radial seal is arranged between the closing body 5 and the valve seat 6. Alternatively, the position can be determined by the closing body 5 being brought into contact with the valve seat 6.

[0039] The lifting drive 13 comprises a component which forms part of the first coupling 14, which in Fig. 1 is shown schematically. This component can be designed as a first flange 25 and is arranged on a side of the lifting drive facing the valve housing 1.

[0040] On a side of the actuator 13 opposite the first flange 25, and thus on a side of the actuator 13 facing away from the valve housing 1, is the second coupling 16, with which the measuring device 15 is releasably attached to the actuator 13. This second coupling 15 can have a second flange 26 attached to the actuator 13 and a counterflange 27 provided on the measuring device 15. The second flange 26 and counterflange 27 can be releasably fixed with a coupling clamp 28.

[0041] In the measuring device 15, a sensor rod 29 is arranged to be movable along the stroke axis A. The sensor rod 29 is designed to be connectable to the drive rod 22, for example with a screw connection in which one of the rods has an external thread and the other rod has a bore with an internal thread.

[0042] The sensor rod 29 comprises a first sensor 30. The first sensor 17, the second sensor 18, and the first sensor 30 are preferably designed based on a contactless operating principle. The sensors 17 and 18 can, in particular, be proximity switches or proximity initiators.

[0043] The first sensor 30 is advantageously designed as a shoulder of the sensor rod 29. The sensor rod 29 has a change in its diameter, which results in a difference in the distance between a surface of the sensor rod 29 and the second measuring sensor 18 depending on the position of the sensor rod 29 along the stroke axis. In particular, this distance changes during the switching process of the stroke drive 13, during which the sensor rod 29 and the first sensor 30 are driven. This change in distance causes an excitation of the second measuring sensor 18. The position of the sensor rod 29 corresponding to the activated state of the second measuring sensor 18 is shown in Fig. 2 shown, in which the lifting drive 13 is in the first end position E1. Excitation of the second sensor 18 therefore means that the lifting drive 13 is in the first end position E1.

[0044] The first sensor 30 can be designed as an additional component, for example, as a ring. However, the sensor rod 29 and the first sensor 30 are preferably constructed as a single piece. This is more cost-effective to manufacture and reliable in operation, since the position of the first sensor 30 on the sensor rod 29 cannot change.

[0045] A second sensor 31 is provided, which is carried by the drive rod 29 as it moves along the stroke axis A.

[0046] Like the first sensor 30, the second sensor 31 can also be designed as an additional component, for example as a ring. Preferably, however, the second sensor 31 is designed as a single piece with the drive rod 22. This is more cost-effective to manufacture and reliable, since the position of the first sensor 30 on the sensor rod 29 cannot change. Preferably, one end of the drive rod 22 acts as a second sensor 31, in that an outer diameter of the drive rod 22 is larger than an outer diameter of the sensor rod 29, thus forming a shoulder or step. This shoulder excites the proximity switch, here specifically the first measuring sensor 17, as soon as the drive rod is in the second end position E2 according to Fig. 3 because then the second sensor 31 in the form of the shoulder and the first measuring sensor 17 are at the same height along the stroke axis A.

[0047] It has been customary to detect the end position E1 with the first sensor 17 and the end position E2 with the second sensor 18. In the device presented here, however, the end position E1 is detected according to Fig. 2 detected by the second sensor 18, while the end position E2 according to Fig. 3 is detected by the first sensor. The sensor closer to the linear actuator 13 therefore measures the position in which the actuator rod 22 is displaced furthest toward the measuring device 15.

[0048] One advantage of this design is the shortening of the arrangement comprising the stroke drive 13 and the measuring device 15. This occurs when the second sensor 31, in the first end position E1, is moved into the area of ​​the second clutch 16, i.e., to its axial height relative to the stroke axis A. This area is not accessible to measurement due to the clutch components, and only reversing the measurement makes it possible to position the second sensor 31 in the first end position E1. A further advantage is that the measuring sensors 17 and 18 no longer have to be spaced apart from each other by the length of the valve stroke along the stroke axis A. This also enables a more compact design.

[0049] This basic principle can be supplemented by beneficial further training.

[0050] A chuck 32 may be provided, which is arranged on the sensor rod 29. It extends in the direction of the stroke axis A between the first and second sensors 30 and 31. The chuck 32 and the two sensors 30 and 31 are designed such that their outer surfaces are flush with one another. This prevents one of the sensors 30 or 31 from directly colliding with one of the measuring sensors 17 or 18 or from a particle from the sensor 30 or 31 being pressed against the measuring sensor 17 or 18. This pressure or a collision can misalign or even destroy the measuring sensors 17 and 18. The aforementioned design of the outer surfaces prevents this. The chuck 32 also prevents a potential source of danger due to shearing or collision of body parts. The flush outer surfaces of the chuck 32 with the sensor 30 allow purely tangential contact. The chuck 32 can be a slide-on sleeve or a cast-on component.The material of the chuck 32 is selected so that it does not excite any of the sensors 17 and 18 and does not impair the functions of the transmitters 30 and 31 and sensors 17 and 18.

[0051] Two further measures, each implemented individually or both together, improve the security of the measuring device 15 against the penetration of objects into the space between the sensors 30 and 31 and the measuring sensors 17 and 18.

[0052] A first measure is to provide the measuring device 15 with a hollow rod 33. This extends over the full length of the sensor rod 29 protruding from the lifting drive 13 along the lifting axis A. Furthermore, it completely encloses the sensor rod 29 in the circumferential direction.

[0053] The hollow rod 33 is interrupted to allow the measuring sensors 17 and 18 access to the transmitters 30 and 31. This can be done in the form of a first elongated hole 34, in which the first measuring sensor 17 is received, and a second elongated hole 35, in which the second measuring sensor 18 is mounted. The elongated holes allow positioning and, in particular, displacement of the measuring sensors 17 and 18 along the stroke axis A. Preferably, the hollow rod 33 has as few interruptions as possible, for example, the aforementioned elongated holes 34 and 35, as well as a drainage opening, if necessary, and an air connection as described further below.

[0054] A second measure is to close one end of the measuring device 15, which is located on the side of the measuring device facing away from the lifting drive 13, with a cover 36. This prevents a collision of one end of the sensor rod 29 with objects and prevents objects from penetrating the measuring device 15.

[0055] The measuring device 15 can have a one-piece housing. A hollow rod 33 and a cover 36 can then be molded onto this. This is structurally simple and hygienically advantageous.

[0056] The measuring device according to the example is further developed in such a way that it contains a simple, safe and compact air supply to the lifting drive 13.

[0057] The cover 36 has an air connection 37, which is arranged, for example, on one end face. The sensor rod 29 comprises, at an end facing away from the lifting drive 13, a piston section 38 that is movable on a running surface 39. A piston seal 40 seals between the piston section 38 and the running surface 39. The sealing effect remains intact throughout the entire stroke and thus the movement between the first and second end positions E1 and E2.

[0058] The sensor rod 29 is completely penetrated by an air duct 41 in the direction of the stroke axis A.

[0059] The air channel 41 is fluidically connected to a second air channel 42, which is provided in the drive rod 22. The second air channel 42 is connected via an outlet 43 to a pressure chamber 44, which is located on the side of the piston 21 facing away from the spring 23.

[0060] Pressure medium, for example pneumatic air, passes through the air connection 37 into the air channel 41, from there into the second air channel 42 and through the outlet 43 into the pressure chamber 44 and causes pressure to be applied to the piston 21. At a sufficiently high pressure, the counterforce of the spring 23 is overcome, the piston 21 is displaced and the lift valve is subsequently switched. List of reference symbols

[0061] 1Valve housing 2Interior 3First connection 4Second connection 5Closing body 6Valve seat 7Valve stem 8Seal 9Lantern 10Lantern flange 11Housing flange 12Clamp 13Lifting actuator 14First coupling 15Measuring device 16Second coupling 17First sensor 18Second sensor 19First measuring line 20Second measuring line 21Piston 22Actuator rod 23Spring 24Stop 25First flange 26Second flange 27Counter flange 28Coupling clamp 29Sensor rod 30First sensor 31Second sensor 32Chuck 33Hollow rod 34First slot 35Second slot 36Cover 37Air connection 38Piston section 39Running surface 40Piston seal 41Air duct 42Second air duct 43Outlet 44Pressure chamber ALifting axis E1First end position E2Second end position

Claims

1. A lift valve having a valve housing (1) and a lift drive (13), which comprises a drive rod (22) that is movable along a lift axis (A) into a first and a second end position (E1, E2), and a measuring apparatus (15) that is coupled to the lift drive (13) on a side of the lift drive (13) facing away from the valve housing (1) and that comprises a first measuring sensor (17) and a second measuring sensor (18), and having a first transducer (30), which is arranged so as to follow the movement of the drive rod (22), wherein the first transducer (30) is arranged on a sensor rod (29) arranged in an end region of the drive rod (22), wherein a second transducer (31), which is arranged so as to follow the movement of the drive rod (22), is provided, and the first measuring sensor (17) is arranged between the second measuring sensor (18) and the lift drive (13), and the first measuring sensor (17) is excited by the second transducer (31), which is arranged on a side of the first transducer (30) facing the drive rod (22), when the drive rod (22) is located in the second end position (E2), characterized in that the first measuring sensor (17), which is placed closer to the lift drive (13), responds to the second transducer (31) when the drive rod (22) is displaced the farthest in the direction of the measuring sensors (17, 18).

2. The lift valve according to claim 1, characterized in that the sensor rod (29), the first transducer (30), and the second transducer (31) have flush lateral surfaces.

3. The lift valve according to claim 1 or 2, characterized in that the first transducer (30) is designed integrally with the sensor rod (29).

4. The lift valve according to claims 1 to 3, characterized in that the second transducer (31) is designed integrally with the drive rod (22).

5. The lift valve according to one of the preceding claims, characterized in that the measuring apparatus (15) is closed with a cover (36) on an end face facing away from the lift drive (13).

6. The lift valve according to claim 5, characterized in that the sensor rod (29) is accommodated in the cover (36) so as to be displaceable and in a sealed manner, the cover has an air connection (37), and an air channel (41) is formed in the sensor rod (29).

7. The lift valve according to one of the preceding claims, characterized in that the lift drive (13) and the measuring apparatus (15) are connected to one another in a coupling region and the second transducer (31) is located in the first end position (E1) at the height of the coupling region.

8. The lift valve according to one of the preceding claims, characterized in that the measuring apparatus (15) comprises a hollow rod (33), which completely surrounds the sensor rod (29).

9. The lift valve according to one of the preceding claims, characterized in that the first measuring sensor (17) is accommodated in a first elongated hole (34) and the second measuring sensor (18) is accommodated in a second elongated hole (35).

10. The lift valve according to one of the preceding claims, characterized in that the drive rod (22) can be coupled to a valve rod (7) of the lift valve.

11. The lift valve according to one of the preceding claims, characterized in that the drive rod (22) is designed so as to be connectable, in particular by means of a screw connection, to the sensor rod (29).