DE202021106467U1 - Control valve unit with a valve housing - Google Patents

Abstract

Control valve unit (10) with a valve housing (12), a valve rod (14) which can be displaced axially in the valve housing (12) for actuating an actuator, a seal (42) assigned to the valve rod (14) and the housing (12), a spring element, (46) which acts on the seal (42), and a measuring device for detecting a change in the axial extension of the seal (42), the seal (42) in an axial direction with one axial end on a counter bearing (44) on the valve housing (12) and the spring force of the spring element (46) acts on the seal (42) via the other axial end, and the measuring device has a sensor unit that detects an axial change in length of the seal (42) relative to the counter bearing (44) by means of a Sensor unit determined, characterized in that the sensor unit as a tooth structure measuring device comprising an in axial operative connection with the seal (42) standing tooth structure (20) and at least one gehäusef first sensor (16, 18), the tooth structure (20) moving with a change in the axial extension of the seal (42) and moving relative to the sensor (16, 18) fixed to the housing.

Description

The invention relates to a control valve unit with a valve housing according to the type specified in the preamble of claim 1.

Control valve units are used, among other things, to regulate process fluids and comprise a valve stem which is sealed to a valve housing by means of a seal. The seal comprises a sealing element in the manner of a stuffing box, which has a packing and a pressure sleeve which compresses the packing axially and on which a contact force is exerted, in particular via a spring element. Depending on the operating conditions, for example aggressive media and/or high temperatures, the packing can be made of different materials, for example PTFE or aramid. Various lubricants and impregnating agents are added to the material. The axial force exerts a radial pressure on the sealing element on the valve rod and on the valve housing. However, this type of seal has the disadvantage that it is subject to wear and settling properties during operation. This seal will leak over time as the packing load is released. It is therefore necessary to detect the leaking of the sealing element.

the DE 10 2014 015 888 B4 discloses a control valve comprising a seal. The control fitting is designed as a control valve unit in the manner already described. A leaking of a sealing element of the seal is detected by detecting the change in position of a pressure sleeve relative to the valve housing. The change in position is detected on the one hand by the change in position of a display element relative to a groove by means of optical reading and, in another development, by a magnet with associated sensor introduced in some areas along the valve rod in the axial direction. This form of detection has a high degree of inaccuracy and a more quantitative determination of a change in position.

the DE 20 2031 104 690 U1 describes a control valve unit of a known type. The detection of a leak in the sealing element is also implemented here by detecting a change in the position of the pressure sleeve in relation to the valve housing. The change in position is detected by the interaction of a magnet, which is fastened to the pressure sleeve so that it can move axially, and a sensor unit which is stationarily arranged on the valve housing and has a magnet-sensitive sensor. A slight twisting of the pressure sleeve in the circumferential direction leads to measurement inaccuracies. In order to enable the magnet to move with little friction in the axial direction, the magnet guide is equipped with radial play. The radial play leads to a measurement inaccuracy. Furthermore, at least two spring elements are provided in another embodiment. If the spring elements are not tightened evenly, the resulting angle of the pressure sleeve to the central axis of the control valve also leads to measurement inaccuracies in the sensor unit.

The object of the invention is to further develop a control valve unit with a valve housing according to the type specified in the preamble of claim 1 in such a way that measurement inaccuracies and disturbance variables are minimized when determining the change in position of the pressure sleeve relative to the valve housing.

This object is achieved by the characterizing features of claim 1 in conjunction with its preamble features.

The dependent claims form an advantageous further development of the invention.

The invention is based on the finding that a sensor unit for axial changes in position with an associated circumferential, non-radially delimited measuring element on a control valve unit reacts insensitively to a circumferential and/or tilting movement.

According to the invention, the sensor unit is designed as a tooth structure measuring device, comprising a tooth structure that is axially operatively connected to the seal and at least one sensor fixed to the housing. The tooth structure moves with a change in the axial extent of the seal and thus relative to the housing-fixed sensor.

The spring force of the spring element can be applied to the seal between the seal and the tooth structure. This results in a compact design, which leads to advantages in construction.

The toothed structure is preferably worked into or applied to a pressure sleeve that at least partially surrounds the valve rod, with the pressure sleeve being connected to the spring element, in particular bearing against it, and being connected to the seal, in particular bearing on it. This design allows material and production costs to be minimized.

According to an advantageous embodiment of the invention, the tooth structure is formed by a machining process, an embossing process or a rolling process drive manufactured. These methods enable high precision in the manufacturing process.

A sleeve preferably has the tooth structure so that conventional pressure sleeves can be retrofitted.

The sleeve is preferably applied to the pressure sleeve. This allows different requirements and functionalities to be implemented separately on both components.

In order to enable magnetization, at least the tooth structure is made of ferritic material.

In a further embodiment of the invention, the sleeve is made of ferritic material. This enables magnetization of the entire sleeve.

The tooth structure preferably has a trapezoidal, cuboid and/or part-circular external shape in cross section. This allows the structure to be adapted to the prevailing production conditions and signal requirements.

The tooth structure preferably encloses the valve rod at least in regions, in particular completely. This simplifies the manufacturing process and the functionality of the sensor unit.

According to a further embodiment of the invention, the seal is designed as a packing of a stuffing box.

The spring element is preferably formed from at least two springs. In the event of a spring breakage of a spring, a leakage due to the further action of the other spring is thus avoided.

A magnetic sensor is used to detect axial position changes in order to achieve a very high position resolution with simultaneous resistance to twisting and tilting of the measuring element. The magnetic sensor is based on the giant magnetoresistance effect (in short: GMR effect). This design is advantageous due to the non-contact detection of the measured value.

A further advantageous embodiment has an optical sensor unit. An optical sensor unit is particularly advantageous because of the simple, automation-capable sensor technology and the magnet-free operation in an area surrounded by electrical components.

The sensor unit can have a tooth structure and at least two sensors. As a result, the influence of the disturbance variables, for example a tilting of the tooth structure relative to the valve housing, is significantly minimized by combining the two signals. In order to be able to optimally detect the tilting, the sensors are attached at an angle, in particular at a right angle, to the two springs.

Preferably, the sensors are equidistantly spaced from each other around the valve stem.

The sensor preferably has its own voltage source, in particular an accumulator. This ensures that the power supply of the sensor is independent of the control valve unit. The sensor unit thus detects a change in position of the sealing element before the control valve is put into operation and enables the spring element to be set before it is put into operation.

In a further embodiment of the invention, the sensor has an electrical input device, by means of which the zero point of the position of the tooth structure relative to the sensor is defined and stored. This enables qualitative monitoring of the change in position.

The control valve unit preferably has a control unit, in particular a microcontroller, in which the force-displacement characteristic of the spring element is stored and which determines a spring force via the change in position and displays it if it falls below or exceeds a specific contact pressure. The functionality of the spring element can thus also be automatically monitored by the control unit.

According to a further embodiment of the invention, a display device is provided for the sensor. This makes it possible for an operator to monitor the sealing property of the sealing element.

The sensor can also be designed in such a way that it detects the change in position and the contact force of the spring element over a period of time, with this data being able to be output as required, in particular via a display device. Continuous monitoring is possible as a result of the detection over a time interval, as a result of which the measurement of the sensor unit is designed to be reliable.

In particular, the alarm device emits a first warning signal when a predetermined value of the change in position is exceeded, and when it exceeds If the contact pressure force falls below or falls below a predetermined value, a second warning signal sounds. With two different warning signals, it is also possible to detect a decrease in the spring force of the spring element.

In order to carry out an automated setting of the spring element, at least one actuator, in particular a servomotor, is provided.

A prestressing device is preferably provided, via which the prestressing of the spring element and thus the contact pressure force acting on the seal can be adjusted. As a result, a simple adjustment function for the spring element is implemented.

Further advantages, features and application possibilities of the present invention result from the following description in connection with the exemplary embodiments illustrated in the drawings.

• 1 eine perspektivische Ansicht von schräg oben auf ein Stellventil, umfassend ein Ventilgehäuse und zwei Sensoren gemäß einer ersten Ausführungsform der Erfindung;
• 2 eine perspektivische Ansicht von der Seite auf das Stellventil von 1 mit einem Sensorgehäuse;
• 3 eine Schnittansicht des Stellventils von 2;
• 4 eine perspektivische Ansicht von schräg oben auf ein Stellventils gemäß einer zweiten Ausführungsform der Erfindung, umfassend eines Ventilgehäuses, zwei Federn und zwei Sensoren;
• 5 eine Schnittansicht des Stellventils von 4.

In the description, in the claims and in the drawing, the terms used in the list of reference numbers given below and associated reference numbers are used. In the drawing means:

• 1 a perspective view obliquely from above of a control valve comprising a valve housing and two sensors according to a first embodiment of the invention;
• 2 a perspective view of the control valve from the side of FIG 1 with a sensor housing;
• 3 a sectional view of the control valve of FIG 2 ;
• 4 a perspective view obliquely from above of a control valve according to a second embodiment of the invention, comprising a valve housing, two springs and two sensors;
• 5 a sectional view of the control valve of FIG 4 .

1 shows a perspective view obliquely from above of a control valve 10, comprising a valve housing 12, a valve rod 14 and a measuring device, comprising a first sensor 16 and a second sensor 18 and a circumferential tooth structure 20 on the valve rod 14.

An adjustable nut 22 , an intermediate plate 24 and a cover plate 26 are arranged on valve housing 12 , which includes valve rod 14 , in the axial direction along valve rod 14 . The nut 22, the intermediate plate 24 and the cover plate 26 each have a central opening in which the valve rod 14 is slidably mounted. The cover plate 26 is provided with four connecting openings 28, through which the cover plate 26 can be connected to the intermediate plate 24 and the nut 22 via connecting elements, for example screws, which are not shown. The connection openings 28 are each introduced at the same distance from one another in the circumferential direction.

The tooth structure 20 with individual profile elevations is located above the cover plate 26 . This tooth structure 20 is introduced into a sleeve 30 in some areas in the axial direction and circumferentially in the circumferential direction. The sleeve 30 surrounds the valve rod 14 completely. The individual profile elevations of the tooth structure 20 are evenly spaced from one another. In another embodiment, the ridges of tooth structure 20 are unevenly spaced. The sleeve 30 extends axially along the valve rod 14 at one end through the central openings into the valve housing 12 and at the other end beyond the sensors 16,18. The sleeve 30 is mounted so that it can be displaced in the axial direction along the valve rod 14 and is designed to completely surround the valve rod 14 in the circumferential direction. The central openings of the cover plate 26, the intermediate element 24 and the valve housing 12 are designed in such a way that the sleeve 30 can be displaced in the opening without contact.

The profile structure of the tooth structure 20 can preferably be designed in the shape of a trapezoid, cuboid or partial circle, depending on the signal requirement. The tooth structure 20 is preferably produced by a machining process, an embossing process or a rolling process.

The tooth structure 20 is formed from a ferritic material. In another embodiment, the entire sleeve 30 including the tooth structure 20 is made from ferritic material.

In the axial direction at the level of the tooth structure 20 are the first sensor 16, comprising a first printed circuit board 32 and a first MR chip 34, which has a bias magnet, and the second sensor 18, comprising a second printed circuit board 36 with a second MR Chip 38 having a bias magnet attached. The MR chips 34, 38 are each arranged on the printed circuit boards 32, 36. These are connected to the cover plate 26 in a stationary manner in relation to the sleeve 30. FIG. The two sensors 16, 18 are mounted opposite one another at the same distance in the circumferential direction.

The sensors 16, 18 are magnetic sensors that use the GMR effect to determine a change in position of the tooth Structure 20 to the two stationary sensors 16, 18 make use of. On the one hand, the sensors 16, 18 generate a magnetic field by means of the bias magnets applied to the MR chips 34, 38 and, on the other hand, the sensors 16, 18 detect this using the MR chips 34, 38 integrated on the printed circuit boards 32, 36 .

Alternatively, optical sensors 16, 18 can detect the change in position of the tooth structure 20 relative to the sensors 16, 18 by an optical sensor system.

The sensors 16, 18 have an accumulator in order to enable monitoring of the change in position of the tooth structure 20 relative to the sensors 16, 18 independently of the operation of the control valve 10. Furthermore, batteries are also used as a voltage source for the sensors 16, 18.

In 2 12 is a side perspective view of the control valve 10. FIG 1 shown. In addition to 1 a sensor housing 40 is arranged on the cover plate 26 . The sensor housing 40 extends in the axial direction along the valve rod 14 at the free end beyond the two sensors 16, 18 also. In addition, the sensor housing 40 has two partial elevations 40a and 40b, which extend in areas in the circumferential direction and in areas in the axial direction along the valve rod 14 beyond the sensors 16, 18. The partial elevations 40a, 40b stand on a housing base 40c. A sensor 16, 18 is arranged on the side walls 40d, 40e on each of the two partial elevations 40a, 40b. Both sensors 16, 18 are offset from each other. The sensor housing 40 has in each of the two partial elevations 40a, 40b a connection opening 28 for connection to the cover plate 26, the intermediate plate 24 and/or the valve housing 12 by means of a screw (not shown here).

3 shows a sectional view of the control valve 2 , in which only the first sensor 16 is visible. The sectional view shows, in addition to the elements already described 1 and 2 a sealing element 42 against which the upper end of the sealing element 42 rests at the lower end of the sleeve 30 . In addition, a spring element 46 concentrically surrounding the sleeve 30 is mounted within the valve housing 12 .

The sealing element 42 rests in the axial direction along the valve rod 14 downwards on a projection 44 of the valve housing 12 in a form-fitting manner. Furthermore, the spring element 46 is arranged in the axial direction along the valve rod 14 between the cover plate 26 and the intermediate plate 24 . In the radial direction, the spring element extends shorter than the radial extension of the cover plate 26 and the intermediate plate 24.

The spring element 46 acts in the axial direction with a predetermined preload along the valve rod 14 between the sleeve 30 and the cover plate 26. The spring element 46 rests against the cover plate 26. The sleeve 30 has a rigid spring projection 48 which interacts with the spring element 46 via a transmission element 50 . The transmission element 50 extends further in the radial direction towards the valve rod 14 from the sleeve 30 than the spring projection 48 . The locking projection 52 extends in the radial direction towards the valve rod 14 and is shorter than the free end of the spring projection 48, but longer than the radial extension of the end of the transmission element 50 facing away from the sleeve 30.

The sealing element 42 is designed as a packing of a stuffing box.

The spring element 46 is prestressed and adjusted by the connection receptacle 54 interacting with a connection element, not shown here. The intermediate plate 26 and the valve housing 14 can be adjusted in relation to one another, but are connected in a stationary manner during operation, for example by means of a screw connection.

Through the action of the spring force of the spring element 46 between the fixed cover plate 26 and the sleeve 30 via the transmission element 50, the sleeve 30 is pressed in the axial direction along the valve rod 14 downwards onto the sealing element 42 with the prestressing force of the spring element 46. As a result, the sealing element 42 is compressed and seals in the axial direction and also in the radial direction between the valve rod 14 and the valve housing 12 .

When the sealing element 42 wears, the sealing element 42 yields in the axial direction. The axial extension along the valve rod 14 of the sealing element 42 is reduced. This results in a movement of the sleeve 30 along the valve rod 14 in the direction of the sealing element 42 by means of the spring force applied to the sleeve 30 resulting from the prestressing of the spring element 46. This is accompanied by a change in the axial position of the tooth structure 20 applied to the sleeve 30 in relation to the stationary sensors 16 , 18. The sensors 16, 18 detect this axial change in position.

The sensors 16, 18 preferably have an input device by means of which a zero point of the Position of the tooth structure 20 relative to the sensors 16, 18 is adjusted.

The sensors 16,18 are connected to a microcontroller, not shown here. The force-displacement characteristic of the spring element 46 is stored in the microcontroller. Furthermore, the contact pressure and the change in position over time are recorded in the microcontroller. Through the interaction of the microcontroller with the sensors 16, 18 detecting the change in position, the contact pressure of the spring element 46 is monitored and, for example, a broken spring can be detected. A spring fracture is characterized by a sudden decrease in the contact pressure force and, associated therewith, a reduced elongation of the spring element 46 in the axial direction.

The sensors 16, 18 also have a display element through which the change in position and the contact pressure are displayed over time. This display element generates a first warning signal for overwriting a predetermined value of the change in position and a second warning signal for falling below and/or exceeding a predetermined value of the pressing force.

Due to the further radial extension of the transmission element 50 compared to the radial extension of the blocking projection 52, the elongation of the spring element 46 in the axial direction along the valve rod 14 is limited. In the axial position in which the transmission element 50 acts on the locking projection 52, the spring projection 48 is in the same axial position along the valve rod 14 as the locking projection 52. This position represents the maximum detectable change in position of the tooth structure 20 in relation to the sensor 16.

Furthermore, a servomotor, not shown in detail here, is provided for adjusting the position and the contact pressure of the spring element 46 .

The tooth structure 20 according to 1 until 3 is square-shaped.

the 4 shows a perspective view obliquely from above of a control valve 10, in which the spring element 46 is formed by a first spring 46a and a second spring 46b.

The valve housing 12 has two retaining pins 56a, 56b, see 5 , Which are encompassed concentrically by the associated springs 46a, 46b. Both springs 46a, 46b rest against the cover plate 26 through which the retaining pins 56a, 56b pass. The retaining pins 56a, 56b protrude beyond the cover plate 26. An adjusting nut 58a, 58b is screwed onto the free end of the retaining pins 56a, 56b. By means of this adjusting nut 58a, 58b, the springs 46a, 46b can be adjusted in the axial direction by turning the adjusting nuts 58a, 58b in or out with regard to their preload. Turning the adjusting nut 58a, 58b moves the cover plate 26 up or down, respectively. This movement compresses or relaxes the springs 46a, 46b, and the preload is thus adjusted. The two springs 46a, 46b can be adjusted independently of one another. The two springs 46a, 46b are arranged opposite one another at the same distance from one another around the valve rod 14.

In 4 two sensors 16, 18 are also shown, which are arranged opposite one another at the same distance from one another. The sensors 16, 18 are arranged in such a way that they are arranged in alignment between the two springs 46a, 46b. This is particularly advantageous in order to be able to detect tilting due to uneven adjustment of the first springs 46a in relation to the second spring 46b and vice versa.

The sensor housing 40 is arranged on the upper side of the cover plate 26 and connected to the cover plate 26 . The sensor housing 40 is comparable to 2 formed in some areas in the axial direction along the valve rod 14 . Furthermore, the partial elevations 40a, 40b are arranged as separate components on the sensor housing 40 and are connected to the sensor housing 40. The sensors 16, 18 rest against the side walls 40c, 40d of the two partial areas 40a, 40b.

The intermediate plate 24 is designed as a rectangular plate which, instead of the transmission element 50, interacts with the two springs 46a, 46b. The intermediate plate 24 interacts with the sleeve 30 in the axial direction along the valve rod 14 via the spring projection 48 .

the 5 shows a sectional view of the control valve 4 .

The measuring device described, comprising the sensors 16, 18 and the tooth structure 20, creates a control valve unit 10 with a valve housing 12 in a simple manner, which is based on measurement inaccuracies, twisting and tilting of the valve rod 14 when determining the change in position of the tooth structure 20 in relation to the sensor 16, 18 reacts insensitively.

Reference List

10

control valve

12

valve body

14

valve stem

16

first sensor

18

second sensor

20

tooth structure

22

mother

24

intermediate plate

26

cover plate

28

connection opening

30

sleeve

32

first circuit board

34

first MR chip

36

second circuit board

38

second MR chip

40

sensor housing

40a

first partial survey

40b

second partial survey

40c

case base

40d

first side wall

40e

second side wall

42

sealing element

44

head Start

46

spring element

46a

first spring

46b

second spring

48

spring protrusion

50

transmission element

52

locking tab

54

connection establishment

56a

first holding element

56b

second holding element

58a

first closure element

58b

second closure element

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102014015888 B4 [0003]
• DE 202031104690 U1 [0004]

Claims (25)

Control valve unit (10) with a valve housing (12), a valve rod (14) which can be displaced axially in the valve housing (12) for actuating an actuator, a seal (42) assigned to the valve rod (14) and the housing (12), a spring element, (46) which acts on the seal (42), and a measuring device for detecting a change in the axial extension of the seal (42), the seal (42) in an axial direction with one axial end on a counter bearing (44) on the valve housing (12) and the spring force of the spring element (46) acts on the seal (42) via the other axial end, and the measuring device has a sensor unit that detects an axial change in length of the seal (42) relative to the counter bearing (44) by means of a Sensor unit determined, characterized in that the sensor unit as a tooth structure measuring device comprising a tooth structure (20) in axial operative connection with the seal (42) and at least one housing fixed sensor (16, 18), wherein the tooth structure (20) moves with a change in the axial extension of the seal (42) and moves relative to the housing-fixed sensor (16, 18). control valve unit claim 1 , characterized in that the spring force of the spring element (46) between the seal (42) and tooth structure (20) is applied to the seal (42). control valve unit claim 1 or 2 , characterized in that the toothed structure (20) is worked into or attached to a pressure sleeve (30) surrounding the valve rod (14) at least in regions, the pressure sleeve (30) being connected to the spring element (46), in particular bearing against it, and with is connected to the seal (42), in particular rests against it. Control valve unit according to one of the preceding claims, characterized in that the tooth structure (20) is produced by a machining process, an embossing process or a rolling process. Control valve unit according to one of the preceding claims, characterized in that a sleeve has the tooth structure (20). control valve unit claim 6 , characterized in that the sleeve is applied to the pressure sleeve (30). control valve unit claim 6 , characterized in that the sleeve is arranged as a separate component. Control valve unit according to one of the preceding claims, characterized in that at least the tooth structure (20) comprises ferritic material. Control valve unit according to one of Claims 5 to 8, characterized in that the sleeve comprises ferritic material. Control valve unit according to one of the preceding claims, characterized in that the toothed structure (20) has a trapezoidal, cuboid and/or part-circular external shape in cross section. Control valve unit according to one of the preceding claims, characterized in that the toothed structure (20) encloses the valve rod (14) at least in regions, in particular completely. Control valve unit according to one of the preceding claims, characterized in that the seal (42) is designed as a packing of a stuffing box. Control valve unit according to one of the preceding claims, characterized in that the spring element (46) is formed from at least two springs (46a, 46b). Control valve unit according to one of the preceding claims, characterized in that the sensor (16, 18) has a magnetic sensor system, in particular a sensor system based on the GMR effect. Control valve unit according to one of the preceding claims, characterized in that the sensor (16, 18) has an optical sensor system. Control valve unit according to one of the preceding claims, characterized in that at least two sensors (16, 18) assigned to the tooth structure (20) are provided and form a sensor unit with the tooth structure (20). control valve unit Claim 16 , characterized in that the sensors (16, 18) are arranged at the same distance from one another around the valve rod (14). Control valve unit according to one of the preceding claims, characterized in that the sensor (16, 18) has its own voltage source, in particular an accumulator. Control valve unit according to one of the preceding claims, characterized in that the sensor (16, 18) has an input device has, by means of which the zero point of the position of the tooth structure (20) relative to the sensor (16, 18) is defined and stored. Control valve unit according to one of the preceding claims, characterized in that a control unit, in particular a microcontroller, is provided in which the force-displacement characteristic of the spring element (46) is stored and which determines a spring force via the change in position and when a certain contact pressure indicates this. Control valve unit according to one of the preceding claims, characterized in that a display device is provided for the sensor (16, 18). Control valve unit according to one of the preceding claims, in particular according to Claim 18 , characterized in that the sensor (16, 18) detects the change in position and the contact pressure of the spring element (46) over a time interval, these data being output as required, in particular via the display device. Control valve unit according to one of the preceding claims, characterized in that an alarm device is provided which outputs a first warning signal when the position change exceeds a predetermined value and a second warning signal when the contact pressure exceeds or falls below a predetermined value. Control valve unit according to one of the preceding claims, characterized in that the control unit for setting the spring element (46) has at least one actuator, in particular a servomotor. Control valve unit according to one of the preceding claims, characterized in that a prestressing device is provided, via which the prestressing of the spring element (46) and thus the contact pressure force acting on the seal (42) can be adjusted.

Images