Valve control head

Abstract

Valve control head (10) comprising a housing (12), control electronics (14), at least one control valve (20), fluid connections (18), electrical connections (16), a first measuring object (22) rigidly coupled to a first valve closing part, and a position measuring system (32) comprising measuring electronics (48) and a first position sensor (34), wherein the first position sensor (34) can detect a position of the first measuring object (22), and wherein the valve control head (10) has a mounting device (45) configured to couple a second position sensor (36), wherein the position measuring system (32) is equipped with an electronic switch (50), wherein the respective position sensor (34, 36) can be selectively switched to the measuring electronics (48) by means of the electronic switch (50), and wherein the valve control head (10) is modularly designed by means of the mounting device (45).and wherein a second measuring object (24) can be coupled to the valve control head (10) with the second position sensor (36).

Description

[0001] The present invention relates to a valve control head for process valves.

[0002] Valves are an essential control element in the process and automation industries. For operational safety and process control, it is crucial to know the position of a valve and, consequently, the position of its closing element. Process valves have at least one closing element; more complex process valves often have two closing elements to control multiple fluid flows.

[0003] To monitor the position of the valve closing elements, initiators are typically mounted laterally on the process valve. These must be connected to the control head via a cable, which is inconvenient in terms of the required installation space.

[0004] WO 02 / 093 058 A1 discloses a method for controlling the switching movement of a valve, whereby fixed valve positions are detected.

[0005] DE 10 2006 058 398 A1 discloses a control unit for a valve with two closing elements for closing a passage which connects two connection openings, and with position sensors for monitoring the positions of the closing elements.

[0006] DE 20 2010003659 U1 describes a device for end position detection in lifting valves with a sensor module.

[0007] DE 102015109473 A1 discloses a valve with a plunger and with a sensor for detecting an adjustment path of the plunger.

[0008] It is therefore an object of the present invention to provide an improved valve control head which enables particularly simple detection of multiple valve positions. At the same time, the valve control head should be modular in design.

[0009] This problem is solved according to the invention by a valve control head according to the subject matter of claim 1, comprising a housing, control electronics, at least one control valve, fluid connections, electronic connections, a first measuring object rigidly coupled to a first valve closing element, and a position measuring system comprising measuring electronics and a first position sensor, wherein the first position sensor can detect a position of the first measuring object, and wherein the valve control head has a mounting device configured for coupling a second position sensor. The position measuring system is equipped with an electronic switch, in particular a multiplexer. The respective position sensor can be selectively switched to the measuring electronics by means of the electronic switch. The valve control head can be designed modularly by means of the mounting device.A second measuring object can be coupled to the valve control head together with the second position sensor.

[0010] With a valve control head designed in this way, the position of a valve closing element can be reliably detected. The option of installing a second position sensor enables reliable position monitoring even for process valves with two closing elements. These are also referred to as two-way measuring systems. External initiators can be omitted, resulting in a cost-effective and space-optimized control head design.

[0011] The modular design also makes it possible to use many identical parts in the production of the valve control head.

[0012] An electronic switch offers the advantage that large parts of the measurement electronics can be used by both position sensors when a second position sensor is mounted on the control head. This allows the measurement electronics for the control head to be particularly cost-effective. To keep the measurement electronics as simple as possible, both position sensors should operate according to the same measurement principle.

[0013] By allowing the respective position sensor to be selectively switched to the measuring electronics via the electronic switch, both position sensors can share parts of the measuring electronics and the positions of two valve closing parts can be measured with only one measuring circuit.

[0014] The valve closing elements are preferably each rigidly connected to a spindle, wherein, in process valves with two valve closing elements, one spindle is designed as a hollow spindle that is arranged concentrically to the first spindle and is movable independently of the first spindle. The valve closing elements can also be formed integrally with the spindles.

[0015] Each spindle, and in particular the end of the spindle projecting into the valve control head, has a measuring object attached to it. Consequently, the valve closing elements are coupled to the measuring objects via the spindles, such that a movement of a valve closing element results in a corresponding movement of the measuring object.

[0016] To couple the second measuring object to the valve control head along with the position sensor, the position sensor can have projections that hold the measuring object in place. An additional spindle, in particular a hollow spindle, is also coupled to the valve control head via the additional measuring object.

[0017] According to one embodiment, the mounting device can include a plug-in connector. A second position sensor can be attached to the valve control head via the plug-in connector by simply plugging it in and electrically connected to the measuring electronics. For this purpose, the plug-in connector can be designed as a socket into which a plug located on the second position sensor can be inserted. Alternatively or additionally, the mounting device can have mechanical connecting elements, for example, at least one locking element and / or a snap lock.

[0018] Depending on the type of position sensor, a customized signal preprocessing unit may be necessary. Since the signal preprocessing unit is sensor-dependent, it is preferably installed between the position sensors and the switch.

[0019] The second position sensor can preferably be connected externally. This has the advantage that no unnecessary space needs to be allocated for an oversized housing if the second position sensor is not even installed.

[0020] According to one embodiment, the control head can include an additional housing, wherein the second position sensor is arranged in the additional housing. The additional housing can be permanently or detachably attached to the housing of the valve control head. In particular, the additional housing can be attached only if the second position sensor is to be attached to the valve control head. To attach the additional housing, mechanical fasteners, for example snap-fit ​​elements, can be provided. Alternatively, the additional housing can be screwed or glued in place.

[0021] The additional housing can also be used to mount the valve control head on a hydraulic or pneumatic valve actuator.

[0022] Each position sensor can include a measuring coil. A measuring coil allows for the reliable detection of the position of a valve closing element, and in particular the position of a measuring object attached to the valve closing element. For example, the position sensors are designed as Hall effect sensors.

[0023] The object being measured is preferably designed as an electrically and / or magnetically conductive, ferromagnetic core and can be configured as a transmitter or as a target.

[0024] The position sensors can have an essentially hollow cylindrical shape. This shape allows for particularly good integration of the position sensors into the valve control head. In particular, the position sensors can be arranged concentrically to the spindles.

[0025] The position sensors preferably have a space for receiving the objects being measured. The objects can thus be guided within the position sensors in such a way that a measuring voltage is induced by their movement. Particularly preferably, the position sensors provide a continuously changing output signal, so that different valve positions can be detected.

[0026] Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made. The drawings show: - Fig. 1 schematically a valve control head according to the invention for a process valve and - Fig. 2 a circuit diagram of the measuring electronics of a valve control head according to the invention.

[0027] Fig. Figure 1 schematically shows a valve control head 10 designed for controlling a process valve. The valve control head 10 comprises a housing 12 and control electronics 14 arranged therein, electrical connections 16, fluidic connections 18 and control valves 20.

[0028] The valve control head 10 also includes two measuring objects 22, 24, which are attached to two spindles 26, 28 of a process valve, so that the measuring objects 22, 24 move with the spindles 26, 28. One spindle 28 is designed as a hollow spindle, which is arranged concentrically to the first spindle 26 and can move independently of it.

[0029] According to an alternative embodiment, the valve control head 10 can only have a measuring object 22 and a spindle 26.

[0030] A valve closing element can be arranged at each end of the spindles 26, 28. If the valve closing elements are in contact with a valve seat of a process valve, fluid flow through the process valve can be blocked. If the valve closing elements are spaced apart from the valve seat, fluid flow can occur.

[0031] Fluid lines can be connected to the fluidic ports 18 to actuate the valve pneumatically or hydraulically. Such valve actuators are well known in the prior art; therefore, the actuator will not be discussed further here. A valve actuator 30 is only shown schematically.

[0032] The position of the objects 22, 24 can be detected via a position measuring system 32 of the valve control head 10. For this purpose, the position measuring system 32 has a first position sensor 34 and a second position sensor 36. The position sensors 34, 36 have a substantially hollow cylindrical shape and each comprises a measuring coil 38, 40. They are arranged one behind the other along a longitudinal direction of the valve control head 10, with one longitudinal direction of the valve control head 10 corresponding to a direction of movement of the spindles 26, 28. Within the measuring coils 38, 40, the position sensors 34, 36 have a space 42, 44 for receiving the objects 22, 24.

[0033] The objects 22, 24 have an electrically and / or magnetically conductive ferromagnetic core. Consequently, the position of the objects 22, 24, and thus also the position of the spindles 26, 28 and the valve closing elements connected to the spindles 26, 28, can be determined by the position measuring system 32 in a known manner by electromagnetic induction. The valve closing elements are not shown for the sake of simplicity.

[0034] The second position sensor 36 is preferably detachably connected to the valve control head 10, in particular by being plugged into the valve control head 10. For this purpose, the valve control head 10 has a mounting device 45. The mounting device 45 allows the second position sensor 36 to be coupled to the valve control head 10 both mechanically and electrically. The mounting device 45 comprises a plug connector 43 with electrical contacts. The second position sensor 36 has corresponding plug elements that engage in the plug connector 43 for electrical contact. The mounting device 45 also has mechanical connecting elements 47, for example, locking elements. Alternatively, a snap lock can be provided for the mechanical connection.

[0035] The mounting device 45 allows the valve control head 10 to be modularly constructed. The second position sensor 36 only needs to be connected if the process valve has two independently movable valve closing elements. This allows the valve control head 10 to be manufactured in a cost-optimized and space-saving manner.

[0036] The housing 12 can also be modularly expandable. The second position sensor 36 is located outside the housing 12 in an additional housing 46. The additional housing 46 is attached to the housing 12 as needed, i.e., when the second position sensor 36 is also coupled to the valve control head 10.

[0037] In order to make the measuring electronics 48 of the position measuring system 32 as simple as possible, the position sensors 34, 36 can share large parts of the measuring electronics 48.

[0038] This will be demonstrated using a [method] in Fig. 2 shown circuit diagram clearly.

[0039] To enable the shared use of parts of the measuring electronics 48, the position measuring system 32 has a switch 50. This switch can selectively connect the position sensors 34, 36 to the measuring electronics 48. Such switches 50 are also called multiplexers or, in abbreviated form, MUX. Thus, the positions of the objects 22, 24 can be measured with only one measuring circuit.

[0040] Depending on the type of position sensors 34, 36, an individual signal preprocessing unit 52, 54 may optionally be provided. Since the signal preprocessing unit 52, 54 is sensor-dependent, it is interposed between the position sensors 34, 36 and the switch 50.

Claims

[1] Valve control head (10) comprising a housing (12), control electronics (14), at least one control valve (20), fluid connections (18), electrical connections (16), a first measuring object (22) rigidly coupled to a first valve closing part, and a position measuring system (32) comprising measuring electronics (48) and a first position sensor (34), wherein the first position sensor (34) can detect a position of the first measuring object (22), and wherein the valve control head (10) has a mounting device (45) configured to couple a second position sensor (36), wherein the position measuring system (32) is equipped with an electronic switch (50), wherein the respective position sensor (34, 36) can be selectively switched to the measuring electronics (48) by means of the electronic switch (50), and wherein the valve control head (10) is modularly designed by means of the mounting device (45),and wherein a second measuring object (24) can be coupled to the valve control head (10) with the second position sensor (36). [2] Valve control head (10) according to claim 1, characterized by , that a sensor-dependent signal preprocessing device (52, 54) is interposed between the position sensors (34, 36) and the switch (50). [3] Valve control head (10) according to any of the preceding claims, characterized by , that the second position sensor (36) can be coupled outside the housing (12). [4] Valve control head (10) according to any of the preceding claims, characterized by , that the control head (10) includes an additional housing (46), wherein the second position sensor (36) is arranged in the additional housing (46). [5] Valve control head (10) according to any of the preceding claims, characterized by , that the position sensors (34, 36) have an essentially hollow cylindrical shape. [6] Valve control head (10) according to any of the preceding claims, characterized by , that the position sensors (34, 36) have a space (42, 44) for receiving the measuring objects (22, 24).

Images