VALVE UNIT WITH A MEASURING DEVICE

Description

[0001] The invention relates to a control valve unit with a measuring device according to the preamble of claim 1.

[0002] A control valve unit comprises a valve stem which is sealed against a valve housing by means of a sealing arrangement. The sealing arrangement comprises a sealing element in the form of a stuffing box, which has a packing and a pressure sleeve which axially compresses the packing and onto which a contact force is exerted, in particular via a spring element. Depending on the operating conditions, e.g. high temperatures and / or aggressive media, the packing can be made from different components and / or materials, for example aramid, graphite, PTFE, etc. with the addition of various lubricants and impregnating agents. A wide variety of materials are available, each with different settlement properties. The axial compression also creates a radial pressure of the sealing element against the valve stem and the valve housing.However, these types of seals have the disadvantage that they are subject to wear and settlement during operation and will eventually leak as the packing's contact pressure decreases. Automatic axial retensioning of the packing can be achieved using preloaded spring elements.

[0003] It is desirable to detect an early deterioration in the tightness of the sealing arrangement. For example, US Pat. No. 5,549,305 A discloses a sootblower comprising a feed pipe for delivering fluid to a concentrically mounted lance pipe, wherein a sealing arrangement having a packing between the inner surface of the lance pipe and the outer surface of the feed pipe prevents the fluid from escaping from the system. To maintain the sealing effect of the packing during wear, a pressure sleeve engaged with the packing is preloaded by a plurality of coil springs. The springs are preloaded between a fixed and a movable stop of a preloading device connected to the pressure sleeve.

[0004] The desired contact force on the packing can be adjusted by adjusting the number and arrangement of the springs. In one embodiment, elongation of the springs, which occurs due to the decreasing preload force, which in turn is due to packing wear, can be detected by a bolt screwed into the movable stop and extending through a sleeve attached to the fixed stop. The elongation of the springs increases the distance between the fixed and movable stops, causing a head of the bolt to be drawn into the sleeve until it disappears. This is an indication or signal that the springs should be retensioned.

[0005] DE 10 2014 015 888 A1 describes a generic control valve unit with a measuring device. The control valve unit comprises a valve stem sealed against a valve housing by a sealing arrangement. The sealing arrangement has an axially compressible packing received between a counterbearing on the valve housing and a pressure sleeve. The pressure sleeve is mounted for axial movement relative to the valve housing. A spring element is supported on the pressure sleeve via a pressure element and transmits a contact pressure to the packing. The spring element is supported against a preloading device whose distance from the counterbearing is adjustable. As a result, the contact pressure acting on the pressure sleeve can be adjusted by compressing the spring element. A display element of a measuring device detects a change in the position of the pressure sleeve relative to the counterbearing.The display element is designed to be calibrated in such a way that the display can be adjusted relative to the position of the pre-tensioning device after the contact force has been adjusted.

[0006] These types of sealing arrangements are subject to wear and settlement during operation. As a result, the axial compression and the associated radial sealing forces on the valve stem and valve body decrease over time, creating the risk of process fluid escaping from the valve body. When the packing wears or settles, the packing is automatically axially retensioned via preloaded spring elements acting on the pressure sleeve. The forces of the spring elements decrease with increasing elongation according to the spring characteristic curve.

[0007] A control valve unit of the generic type having the features of the preamble of patent claim 1 can be found in the disclosure of CN 102 758 964 B.

[0008] The object of the invention is to provide a control valve unit with a measuring device which enables precise and simple monitoring of a contact pressure of a sealing arrangement by means of sensory detection.

[0009] The problem is solved by the characterizing features of claim 1 in conjunction with its preamble features.

[0010] The subclaims constitute an advantageous further development of the invention.

[0011] In a known manner, a control valve unit has a measuring device and comprises a sealing arrangement that seals a valve stem against a valve housing. The sealing arrangement has a stuffing box with an axially compressible packing that is received between a counterbearing on the valve housing and a pressure sleeve that is mounted axially movable relative to the valve housing. A contact force is exerted on the pressure sleeve by at least one spring element that is supported on a pretensioning device. The spring element is supported on the pressure sleeve via a pressure element. The pressure element can, for example, be designed as a projection of the pressure sleeve, e.g. an annular shoulder. It is also conceivable for the pressure element to be designed as a compression flange that is formed integrally with the pressure sleeve or is supported on the pressure sleeve via a projection of the pressure sleeve.

[0012] The preloading device's distance from the counterbearing is adjustable, allowing the corresponding contact pressure of the spring element to be adjusted. The preloading device can be connected to the valve housing, for example, via connecting elements anchored in the valve housing, such as studs or threaded bolts. The connecting element engages the spring element, whose clamping force is increased by tightening the nuts screwed to the connecting element. If the packing tightness decreases, the pressure sleeve is moved axially toward the counterbearing by the contact pressure of the spring element.

[0013] It is also conceivable for the preloading device to be designed as a two-part housing comprising an adjusting body connected to an adjusting cover. An axially extending spring element is clamped in the housing between a first stop and a second stop spaced therefrom in the direction of the counterbearing, wherein the spring element is pre-assembled in the preloading device under preload without exerting a contact force on the pressure sleeve. When the preloading device is assembled in the control valve unit, an internal thread of the adjusting body is screwed into an external thread of the valve body. This moves the second stop away from the spring element, which is now supported on the first stop of the preloading device and, via the pressure element, on the pressure sleeve. The spring element is supported on the pressure sleeve, in particular with the interposition of a compression flange.The decreasing axial distance between the first stop and the pressure element increases the clamping force of the spring element when the pre-tensioning device is installed.

[0014] Using the energy of the preload force, the spring element exerts a contact pressure on the pressure element and the pressure sleeve in order to move them axially towards the counter bearing in the event of wear or settling of the packing. Depending on the composition of the packing, the preload force should not be set too tightly, for example to minimize friction on the valve stem. However, it must be set high enough to ensure that radial sealing forces prevent the escape of process fluid. If the contact pressure decreases, the packing is automatically retensioned via the preload force of the spring element. The second stop can, for example, serve to limit the axial spring deflection and thus the axial change in position of the pressure sleeve in order to prevent leakage of the process fluid at an early stage if the tightness of the packing decreases.

[0015] A measuring device comprising a measuring element can detect a change in the position of the pressure piece relative to the counter bearing. Detection can be based on an inductive, capacitive, magnetic, or potentiometric mechanism, or similar. It is also conceivable for the measuring element to be designed as a switch actuated by an actuating means to detect the change in the position of the pressure sleeve.

[0016] The relative movement can be used to determine the corresponding wear of the packing. Depending on the settling characteristics and service life of the packing, at maximum deflection of the spring element, either the spring element can be retensioned using the preloading device or the worn-out packing can be replaced to prevent packing leakage due to a decrease in the packing's tightness.

[0017] According to the invention, the measuring device for monitoring the contact pressure on the packing has a sensor unit that is connected to the pretensioning device and interacts with a magnet that is connected to the pressure sleeve, wherein the magnet is mounted on the pretensioning device in an axially guide manner. The sensor unit has a magnetically sensitive sensor that is fixedly arranged on the pretensioning device. The sensor interacts with a magnet that is connected to the pressure sleeve in order to measure changes in the axial position of the pressure sleeve relative to the pretensioning device in a contactless and wear-free manner. The sensor can be designed, for example, as an xMR chip or as a Hall effect sensor. Magnetic sensors are insensitive to temperature fluctuations and are highly accurate and robust.

[0018] The magnet connected to the pressure sleeve is mounted on the preloading device so that it can be guided axially. The magnet is connected to the pressure sleeve, i.e. an axial change in the position of the pressure sleeve causes an axial change in the position of the magnet connected to it. The magnet is arranged in an axial guide on the preloading device. It is arranged in the axial guide with almost no play and with a radial fit, i.e., it is secured against falling out. This means that it is carried within the guide during an axial movement of the pressure sleeve. The magnet is arranged spatially separate from the sensor on the preloading device and, thanks to the almost play-free, axial guide, remains at a fixed radial distance relative to the sensor. The magnet moves relative to the fixedly arranged sensor.This allows the sensor unit to provide a stable distance measurement relative to the magnet in the axial direction, thus determining a precise axial position change of the pressure sleeve. The relative movement indicates corresponding wear of the packing. Both stepwise and continuous position detection of the pressure sleeve are possible, with the axial position change of the pressure sleeve being accompanied by a change in the spring preload force and thus a change in the contact force of the packing. Thus, the contact force of the packing can be monitored via the sensor unit.

[0019] The measuring device has a guide body connected to the preloading device, which forms an axial guide groove in which the magnet is arranged in a manner that prevents it from falling out. The guide body can be designed, for example, as a housing, a screw bolt, a rail, or the like. The guide body forms a guide groove extending in the axial direction, in which the magnet is arranged for axial movement. The guide groove is formed by a material removal on one longitudinal side of the guide body, with the longitudinal side facing the valve rod and being arranged on the pressure sleeve.

[0020] The magnet and a boundary of the guide groove formed by the material removal of the guide body have complementary shapes. This prevents the magnet from falling out and is arranged in the guide groove with virtually no play. Viewed in the axial direction, the magnet can, for example, be cylindrical and the guide groove can be designed as a circle of holes. The guide groove has a boundary that, in cross-section, at least partially encompasses the circle of holes forming the guide groove beyond an equator. The guide body can, for example, form a boundary of the guide groove that is crescent-shaped in cross-section.

[0021] Preferably, the sensor unit is arranged on the guide body. The guide body can be designed, for example, as a sensor housing in which the sensor unit is arranged. In this way, the sensor unit, which is used, for example, in a difficult environment, is mounted in a safe area. The guide body designed as a sensor housing contributes to the robustness and durability of the sensor unit in harsh outdoor applications.

[0022] The sensor of the sensor unit and the magnet are spatially separated from each other in the guide body. Due to the axial guidance of the magnet in the guide groove, the magnet always remains at a fixed radial distance relative to the fixedly mounted sensor unit. This enables stable distance measurement of the measuring device in the axial direction. This ensures reliable wear indication of the packing via the magnetic sensor.

[0023] The preload device and the guide body designed as a sensor housing, in which the sensor is arranged, can in particular be designed as a pre-assembled module. This contributes to simplified assembly of the control valve unit. The guide body can in particular be firmly connected to the preload device. For example, it can be formed integrally with the preload device. Alternatively, it is possible for the guide body to be detachably connected to the preload device, e.g. they can be screwed or clipped together. This has the advantage that the guide body can only be connected to the preload device after the distance between the preload device and the counter bearing has been adjusted, which in particular prevents twisting of the wiring of the sensor unit and / or control unit.

[0024] Preferably, the magnet is arranged to rotate in the circumferential direction of the valve rod. For example, the magnet can be driven along with the rotation of the preloading device about its axis and rotated around the pressure sleeve arranged coaxially with the valve rod. The magnet is connected to the pressure sleeve and mounted for axial movement in the guide groove of the guide body. This embodiment is particularly advantageous when the preloading device for preloading the spring element is screwed into the valve housing via the actuating body, with the guide body either being formed integrally with the preloading device or the preloading device and the guide body being preassembled as an assembly.

[0025] According to a preferred embodiment, the magnet is connected to the printing sleeve via a magnetically conductive adhesive element. The adhesive element is connected to the printing sleeve at a free end, i.e., at an end of the printing sleeve protruding from the pretensioning device. The printing sleeve is made of a non-magnetic material. The magnet adheres to the adhesive element through its magnetic force, via which it is connected to the printing sleeve.

[0026] Preferably, the adhesive element is connected to the pressure sleeve via a fastening ring. The fastening ring, which can be locked in place, ensures that the adhesive element, and consequently also the magnet, are securely positioned on the pressure sleeve.

[0027] The holding element preferably surrounds the valve rod radially. The holding element can, for example, be annular. The holding element is arranged, in particular, as a front-end ring on the pressure sleeve, i.e., the magnet is connected to the pressure sleeve at one end face.

[0028] According to a preferred embodiment, the adhesive element penetrates at least partially radially into the guide groove of the guide body. The guide groove is formed by a material removal on a long side of the guide body, which is directed towards the valve rod or pressure sleeve. The adhesive element, which can in particular be annular, penetrates at least partially into the guide groove, which is arranged on the pressure sleeve and thus on the adhesive element in the direction of the valve rod. In the area of ​​the material removal, the adhesive element can penetrate into the guide body in the radial direction. Viewed in the axial direction, the adhesive element and the guide body overlap in the area of ​​the material removal, i.e. in an area of ​​the guide groove.The at least partial penetration of the adhesive element into the guide groove enables the pressure sleeve to carry the magnet, which is arranged in particular on its front side, in the axial direction in the guide groove when it moves axially due to the wear of the packing.

[0029] According to a preferred embodiment, the sensor unit is communicatively connected to a control unit, which determines the contact force on the package via a force-displacement characteristic curve of the spring element. The sensor unit communicates bidirectionally with the control unit for processing measurement data from the sensor. The sensor unit can, for example, be designed with integrated microelectronics to process the measurement data in the sensor. The sensor and the control unit can, for example, be integrated on a chip. It is also conceivable for the sensor to be connected to an external control unit, i.e., the sensor and the control unit are designed separately.

[0030] To monitor the contact force, the sensor is calibrated as a force sensor. For this purpose, the force-displacement characteristic curve of the spring element can be stored in a data memory of the control unit. The force-displacement characteristic curve describes the relationship between spring force and spring displacement and shows how the spring element behaves during operation. The spring element behaves differently depending on the design. The spring element can be designed in particular as a compact disc spring package, which is suitable for installation in confined spaces where high forces are nevertheless required. Alternatively, it is also conceivable for the spring element to be designed as a helical compression spring. Based on the measured axial change in position of the pressure sleeve, the remaining preload force of the spring element over time can be displayed via the force-displacement characteristic curve during ongoing operation of the control valve unit.This also allows the axial change of the force on the packing to be recorded over time.

[0031] The control unit can be used, for example, to monitor, control, and regulate functions relevant to packing preload, such as automatically monitoring, achieving, and maintaining the desired contact pressure on the packing. Networking the control unit with other devices enables precise monitoring and playback of the pressure sleeve position detection and thus of the packing preload, as well as automatic adjustment of the packing preload.

[0032] The control unit is preferably communicatively connected to an operating unit, wherein the operating unit has at least one display unit and a calibration button. The processed measurement data from the sensor can be forwarded to the display unit so that, for example, a user can read it. It is conceivable for the control unit to be connected, for example, via Bluetooth or the Internet to the operating unit, which can be designed, for example, as a mobile device such as a telephone, tablet or the like. The display unit enables the preload force of the spring element to be displayed and monitored when the preload device is in its pre-assembled state, during assembly of the preload device, and during commissioning of the control valve unit.

[0033] The calibration button on the control unit makes it possible to electronically adjust the sensor to a zero position with great precision. The sensor detects relative movement of the magnet and, consequently, a change in the position of the pressure sleeve. The control unit processes the sensor's measurement data using evaluation electronics and forwards the pressure sleeve's position values ​​to the display unit. During operation, a position value of the pressure sleeve can now be read at any time. Both discrete position detection and continuous position detection of the pressure sleeve over time are possible. This allows the user of the control valve unit to read the change in position of the pressure sleeve via the display unit and determine whether the packing is worn. If the position value of the sensor or pressure sleeve reaches a predefined threshold, an alarm can be issued, for example, so that the packing is either retightened or replaced.

[0034] Furthermore, the force-displacement characteristic curve together with the sensor enables precise adjustment of the axial clamping force of the spring element and a contact pressure on the packing that is adapted to the operating conditions. The sensor is calibrated as a force sensor before the preload device is installed in the control valve unit so that the spring element can be set to a desired contact force. When the preload device is installed in the control valve unit, a start of measurement for the sensor relative to the counter bearing is set using the calibration button. The sensor is zeroed relative to the magnet at the predefined start of measurement. The distance between the preload device and the counter bearing is then reduced, increasing the preload force of the spring element. The preload device moves together with the sensor unit towards the counter bearing, causing the sensor to move relative to the magnet.The axial position change of the preload device corresponds to a change in the preload force of the spring element. The position change of the preload device can thus be carried out up to a predefined sensor value that corresponds to a desired preload force of the spring element. In this way, a predefined axial contact force against the packing can be achieved, with the contact force being specifically tailored to the operating conditions of differently manufactured packings with different lengths.

[0035] The control unit is preferably connected to at least one actuator that is connected to the pretensioning device. The actuator is connected, for example, to the screw nuts of the pretensioning device that are screwed to the connecting element. Alternatively, the actuator can be connected to the actuating body of the housing of the pretensioning device. The actuator converts data received from the control unit into a mechanical movement or rotation. In the event of wear and / or settlement of the packing or when a preset threshold for the change in position of the pressure sleeve and / or a preset pretensioning force of the spring element is reached, an automatic, axial retensioning of the packing advantageously takes place in that the actuator adjusts the tensioning force of the spring element by tightening the pretensioning device.

[0036] Further advantages, features and possible applications of the present invention will become apparent from the following description in conjunction with the embodiments shown in the drawings.

[0037] In the description, claims, and drawings, the terms and associated reference symbols used in the list of reference symbols below are used. In the drawings, the following definitions apply: Fig. 1 shows a section of a sectional view of a control valve unit according to the invention in a first embodiment; Fig. 2 shows a section of a sectional view of a control valve unit according to the invention in a first embodiment in the operating state of the control valve unit; Fig. 3 shows a perspective top view of a measuring device of a control valve unit according to the invention according to Fig. 1 from above; Fig. 4 a plan view of a measuring device of a control valve unit according to the invention according to Fig. 3from above; Fig. 5 a detail of a sectional view of a control valve unit according to the invention in a second embodiment; and Fig. 6 a perspective top view of a second embodiment of a control valve unit according to the invention according to Fig. 5 from diagonally above.

[0038] Fig. 1 to Fig. 6 show a schematic representation of a control valve unit according to the invention, designated overall by the reference number 10.

[0039] In Fig. 1 A section of a first embodiment of a control valve unit 10 according to the invention with a measuring device 52 is shown. The control valve unit 10 has a valve rod 12 and a valve housing 14. The valve rod 12 is sealed from the valve housing 14 by a sealing arrangement comprising a packing 16.

[0040] The packing 16 is arranged axially between a counterbearing 18 and a pressure sleeve 20, which is mounted axially displaceably relative to the valve housing 14. The counterbearing 18 can be part of the valve housing 14 or fixedly arranged in the valve housing 14. The spring-loaded pressure sleeve 20 allows the packing 16 to be axially compressed, thereby achieving an axial and radial sealing effect of the packing 16.

[0041] The contact pressure for compressing the packing 16 is provided by a spring element 22, which in this case is designed as a centered disc spring assembly that radially surrounds the valve rod 12. The spring element 22 is supported on a pretensioning device 24. The pretensioning device 24 has an adjusting body 26 that is sealingly connected to an adjusting cover 28. A first end of the spring element 22 is supported on a first stop 40 formed by the adjusting cover 28. The other end of the spring element 22 is supported, in this case with the interposition of a pressure element 30 in the form of a compression flange, on a second stop 32 formed by the adjusting body 26.

[0042] In the pre-assembled state of the pre-tensioning device 24, particularly in small installation spaces, the spring element 22 is axially pre-tensioned between the first stop 40 and the second stop 32, so that it already generates a pre-tensioning force in the resting state, i.e., before it exerts a contact force on the pressure sleeve 20. In other words, the spring element 22 is adjusted to a desired pre-tensioning force in the pre-tensioning device 24 and is installed in the control valve unit 10 in a pre-tensioned state.

[0043] For mounting the preloading device 24 in the control valve unit 10, the adjusting body 26 has an adjusting thread 34 on an inner side which is brought into engagement with an external thread 36 of the valve housing 14. By tightening the adjusting body 26, the adjusting thread 34 is screwed into the external thread 36. In the present case, the spring element 22 is merely clamped between the first stop 40 and the second stop 32 without exerting an axial contact force on the packing 16. This means that the pressure sleeve 20 rests directly against the packing 16 without any contact force. The preloading device 24 or the second stop 32 is presently in an initial position which can be defined, for example, as a zero position for measuring a change in position of the pressure sleeve 20 due to the settlement properties of the packing 16.

[0044] At an end of the pressure sleeve 20 protruding from the pretensioning device 24, a circumferential fastening ring 42 is arranged, which connects an adhesive element 44 made of magnetically conductive material to the end face of the pressure sleeve 20. A cylindrical magnet 46 adheres to the adhesive element 44 by means of magnetic force. The magnet 46 is axially movable in a guide groove 48 of a guide body 50 connected to the pretensioning device 24. The magnet 46 can move axially slidingly with virtually no friction or play. This allows it to be continuously moved when the pressure sleeve 20 changes its axial position.

[0045] A sensor unit 54 with a magnetically sensitive sensor, for example, an xMR chip or a Hall effect sensor, is arranged in the guide body 50. This sensor unit can detect the axial movement of the magnet 46 without contact. The guide body 50 enables a close, fixed distance to be maintained between the magnet 46 and the sensor unit 54 in the radial direction of the preloading device 24 in order to reliably detect an axial displacement measurement or position of the magnet 46. In the present case, the magnet 46 is located in an area of ​​an optimal start of measurement from the sensor unit 54, i.e., in an axially low position relative to the sensor.

[0046] The sensor unit 54 communicates bidirectionally with a control unit (not shown here), in whose data memory a force-displacement characteristic curve of the spring element 22 is stored and which processes the measurement data of the sensor unit 54 by means of evaluation electronics. The control unit is communicatively connected to an operating unit (also not shown here), which has at least one display unit and a calibration button with which the sensor can be zeroed, for example in the above-described starting position of the pretensioning device 24. Starting from the zero position of the magnet 46 relative to the sensor, the sensor unit 54 can monitor a relative movement of the magnet 46, and consequently a relative axial movement of the pressure sleeve 20, wherein the evaluated measurement data is displayed on a display unit of the operating unit.

[0047] The sensor is advantageously calibrated as a force sensor. This allows the preload force of the spring element 22 in the preassembled state of the preload device 24 as well as the contact pressure on the packing 16 when the preload device 24 is mounted in the control valve unit 10 to be displayed, and the actuating body 26 can be tightened or screwed accordingly. It is conceivable that the measuring device 52, in addition to the cable connection 58, has a battery or rechargeable battery and is thus supplied with power before the entire control valve unit 10 is put into operation. This allows calibration of the sensor and a display of the contact pressure acting on the packing 16 on the display unit before the control valve unit 10 is put into operation.

[0048] In Fig. 2the first embodiment of the control valve unit 10 is shown in an operating state, ie in the prestressed state of the packing 16. For the exact adjustment of the contact force with which the spring element 22 acts on the packing 16, the sensor unit 54 can be used in combination with the force-displacement characteristic curve of the spring element 22 stored in the control unit.

[0049] A desired axial preload force can be set on the packing 16 via the preload device 24. The adjusting body 26 is made of the Fig. 1screwed further into the valve housing 14 into the zero position described by way of example. This results in the first stop 40 and the second stop 32 moving in the direction of the counter bearing 18. As a result, the second stop 32 has an axial distance from the pressure element 30 and the spring element 22 is further compressed between the first stop 40 and the pressure element 30, so that the preload force of the spring element 22 and consequently a contact force on the pressure sleeve 20 and on the packing 16 is increased.

[0050] The axial movement of the pre-tensioning device 24 in the direction of the counter bearing 18 also results in the pressure sleeve 20 extending out of the adjusting cover 28 of the pre-tensioning device 24, so that the magnet 46 carried by the pressure sleeve 20 moves relative to the sensor unit 54. The pre-tensioning device 24 was here compared to Fig. 1screwed into the valve housing 14 via several rotations of the actuating body 26, whereby the magnet 46 and the sensor unit 54 are arranged opposite each other at the same axial height.

[0051] The axial relative displacement of the magnet 46 corresponds to a compression of the spring element 22, and thus to a specific change in the preload force of the spring element 22, which can be determined via the force-displacement characteristic curve and can be displayed via an operating unit (not shown here) connected to the sensor unit 54. Due to the axial adjustment of the preload device 24 or the second stop 32 in the direction of the counter bearing 18, the preloaded spring element 22 now acts on the packing 16. The actuating body 26 is screwed from the zero position into the valve housing 14 until an exact setting of the desired preload force on the packing 16 is achieved. This can be achieved automatically, for example, by means of an actuator connected to the actuating body 26, which can be controlled via the control unit.In this way, the axial contact pressure can be easily adjusted to suit the operating conditions of packings 16 that are manufactured differently and have different lengths.

[0052] Due to the wear and / or settlement characteristics of the packing 16, the spring-loaded pressure sleeve 20 exhibits an axial movement relative to the second stop 32. This movement is proportional to a settlement path of the packing 16 and indicates the state of wear of the packing 16. During the axial movement of the pressure sleeve 20, the magnet 46 is always driven along. Consequently, the axial movement of the magnet 46 relative to the sensor unit 54 corresponds to the movement of the pressure sleeve 20 relative to the second stop 32. During operation, a sensor value corresponding to a position of the pressure sleeve 20 can now be read at any time from a display unit of the control unit. In this way, the settlement process of the packing 16 can be measured and monitored over time. The force-displacement characteristic curve of the spring element 22 can be used to derive the preload force with which the spring element 22 acts on the packing 16, as well as its change over time.This preload force can also be displayed and monitored for appropriate adjustment of the spring preload.

[0053] The pressure sleeve 20 yields to the contact forces of the spring element 22 until the pressure element 30 rests against the second stop 32. The second stop 32 limits the deflection of the preloaded spring element 22 and thus the axial position change of the pressure sleeve 20. If a critical setting value of the packing 16 is exceeded and / or if a predefined preload force is exceeded and / or undershot, an alarm can be triggered, for example. Depending on the nature and / or design of the packing 16, either its service life is exhausted and it must be replaced, or it must be reloaded, for example by automatically retightening the preload device 24 by the actuator connected to the actuating body 26.

[0054] Fig. 3shows a perspective top view obliquely from above of a first embodiment of a control valve unit 10 according to the invention with a measuring device 52 according to Fig. 1 The control valve unit 10 has a preloading device 24 comprising a housing with an adjusting cover 28 and an adjusting body 26, which radially enclose a spring-loaded pressure sleeve 20. The adjusting cover 28 is detachably connected to the adjusting body 26 via screw connections 60, whereby a spring element 22 (not shown here) can be easily mounted in the preloading device 24 in an axially preloaded manner.

[0055] The tensioning force of the spring element 22 is adjustable in this case via the adjusting body 26 of the pretensioning device 24. The adjusting body 26 has an internal adjusting thread 34 (not shown here) for connection to an external thread 36 (likewise not shown here) of a valve housing 14. Screwing the adjusting body 26 into the valve housing 14 causes the spring element 22 to be further compressed between the adjusting cover 28 and the pressure sleeve 20. To adjust the pretensioning device 24, the adjusting body 26 in this case has a jacket surface which is designed with a drive profile for an open-end wrench. It is also conceivable for the adjusting body 26 to have a drive profile for another tool, e.g. a nose hook wrench. Alternatively, the adjustment can be carried out via an actuator connected to the adjusting body 26.A predefined preload force can be set via a defined number of revolutions of the actuating body 26 relative to the valve housing 14, with which the spring element 22 is to act on a packing 16 (not shown here) of a sealing arrangement of the control valve unit 10. Alternatively, the adjustment continues until the display unit again indicates the recommended preload for the packing 16. This can be achieved, for example, by appropriately controlling the actuator.

[0056] A measuring device 52 is arranged on the pretensioning device 24. The measuring device 52 has a guide body 50 in which, in this case, a sensor unit 54 is arranged in a fixed position. The sensor unit 54 has a magnetic sensor that interacts with a magnet 46 connected to the pressure sleeve 20 in order to determine a bearing change of the pressure sleeve 20 due to wear and / or the settlement properties of the packing 16. The axial movement of the pressure sleeve 20 can be determined by the relative movement of the magnet 46 relative to the sensor of the sensor unit 54. To reliably detect an axial displacement measurement of the magnet 46, the sensor is arranged at a radially fixed distance from the magnet 46 in the guide body 50 of the measuring device 52.

[0057] The guide body 50 is arranged on a valve rod 12 arranged coaxially with the pressure sleeve 20. On one longitudinal side of the guide body 50, which is arranged towards the pressure sleeve 20, the guide body 50 has an axially extending guide groove 48 in which the magnet 46 is mounted for axial movement. In the present case, the magnet 46 is cylindrical, and the guide body 50, which partially surrounds the magnet 46 radially, has a complementary shape to the magnet 46 in the region of the guide groove 48, so that the magnet 46 is arranged in the guide groove 48 with virtually no play.

[0058] The magnet 46 is magnetically connected to the pressure sleeve 20. For this purpose, a lockable fastening ring 42 is arranged at a free end of the pressure sleeve 20, which extends out from the pretensioning device 24. The fastening ring 42 serves to fasten a ferromagnetic adhesive element 44 to the pressure sleeve 20. The adhesive element 44 is ring-shaped in this case and radially surrounds the valve rod 12. It is arranged on the end face of the pressure sleeve 20. The adhesive element 44 engages at least partially in the axially extending guide groove 48, which is arranged on a circumferential side of the valve rod 12. In this way, the pressure sleeve 20 can always entrain the magnet 46 during an axial movement due to wear of the packing 16.

[0059] The magnet 46 is arranged so as to be rotatable relative to the valve rod 12 and the holding element 44. This means that with one rotation of the adjusting body 26, the magnet 46 rotates on the holding element 44 in a sliding manner around the valve rod 12. Via the guide body 50, which is firmly connected to the adjusting cover 28, the magnet 46 remains at a constant radial distance relative to the sensor unit 54 despite the rotation of the pretensioning device 24 relative to the valve housing 14.

[0060] In the present case, the guide body 50 is fixedly connected to the adjusting cover 28 of the preloading device 24, with the preloading device 24 and the measuring device 52 being designed as a preassembled unit. The measuring device 52 is supplied with power via a cable connection 58, which can also be used to transmit data to other components of the control valve unit 10, for example, a valve position controller not shown here. The measuring device 52, comprising the guide body 50, the sensor unit 54, the magnet 46, and the cable connection 58, is fixedly connected to the adjusting cover 28 and rotates as a unit around the valve rod 12 when the adjusting body 26 is rotated.

[0061] It is also conceivable that the guide body 50 of the measuring device 52 is detachably connected to the pretensioning device 24, for example screwed or clipped.

[0062] Fig. 4shows a top view of the measuring device 52 Fig. 3from above. It can be clearly seen that the guide body 50 is arranged on the valve rod 12 with a long side forming the guide groove 48. The guide groove 48 encloses the magnet 46 beyond an equator of the magnet 46, preventing it from falling out. The boundary of the guide groove 48 formed by removing material from the guide body 50 here forms at least partially a hole circle and has a complementary shape to the present cylindrical magnet 46. The magnet 46 is thus arranged in the guide groove 48 so as to be axially movable with almost no play. In the area of ​​contact with the magnet 46, the guide groove 48 is advantageously made of a material that has good sliding properties, e.g. POM. Alternatively, the guide groove 48 is coated with such a material. The magnet 46 is usually made of NdFeB and coated on the outside with Ni-Cu-Ni. A combination of the respective materials results in good, play-free sliding guidance.

[0063] The adhesive element 44, which is particularly annular in shape, partially penetrates radially into the guide groove 48 in the material removal area of ​​the guide body 50. Viewed in the axial direction, the adhesive element 44 and the guide body 50 partially overlap in the material removal area. This allows the pressure sleeve 20 to entrain the magnet 46, which is arranged particularly on its end face, in the guide groove 48 during an axial position change.

[0064] Furthermore, it is clearly visible that the magnet 46 is arranged to be rotatable relative to the adhesive element 44, so that when the actuating body 26 rotates around the valve rod 12, it also rotates, adhering to the adhesive element 44. Thus, despite the rotation of the preloading device 24 relative to the valve housing 14, the magnet 46 remains at a constant radial distance relative to the sensor unit 54, whereby the sensor unit can always reliably detect an axial displacement measurement or position of the magnet 46.

[0065] In Fig. 5A section of a second embodiment of a control valve unit 10 according to the invention is shown. The control valve unit 10 has a valve body 14 through which a valve rod 12 passes. The valve rod 12 is sealed against the valve body 14 by means of a sealing arrangement having a packing 16. In order to compress the packing 16, a spring-loaded pressure sleeve 20 is provided, which is acted upon by a pressure element 30. The pressure element 30 cooperates with a spring element 22, which is supported on the one hand on a prestressing element 64 of a prestressing device 24 and on the other hand on the pressure element 30. The spring element 22 and the pressure element 30 are penetrated by a connecting element 62 anchored in the valve body 14, which in this case is designed as a threaded bolt. The preload force of the spring element 22, and thus a pressure load on the pressure sleeve 20 and the packing 16, is controlled via the preload device 24 or.can be changed via a screw nut 56 screwed to the connecting element 62.

[0066] To precisely adjust the desired spring tension on the packing 16, the preloading device 24 can be used in conjunction with a sensor unit 54. The spring element 22 and the preloading device 24 are mounted in the control valve unit 10 such that no pressure acts on the pressure sleeve 20. At this point, a magnetically sensitive sensor of the sensor unit 54 can be zeroed, for example.

[0067] The spring element 22 is then compressed to the desired preload force. For this purpose, the screw nut 56 is turned from the zero position, for example using a torque wrench or an actuator. During rotation, the spring element 22 is compressed between the preload element 64 and the pressure element 30, wherein the axial change in position of the spring element 22 corresponds to a change in the preload force of the spring element 22. Via the pressure element 30, which is supported on a projection 38 of the pressure sleeve 20, the spring element 22 presses on the pressure sleeve 20 in order to axially compress the packing 16. The spring element 22 can be preloaded via the screw nut 56 of the preload device 24 up to a predefined sensor value, i.e. a specific contact force of the pressure sleeve 20 or the packing 16.During the assembly retightening process, a contact pressure acting on the packing 16 can be displayed via a display unit of an operating unit and the screw nut 56 can be tightened accordingly.

[0068] When the screw nut 56 is tightened, the preload force increases and the spring element 22 is compressed. The pressure sleeve 20 moves upward out of the preload element 64. A circumferential adhesive element 44 made of magnetically conductive material is connected to the front of a free end of the pressure sleeve 20 via a fastening ring 42. A magnet 46 adheres to the adhesive element 44 and is mounted in a guide groove 48 in a guide body 50 on the preload element 64 of the preload device 24 for axial movement. The adhesive element 44 penetrates at least partially radially into the guide groove 48, so that the magnet 46 is always driven by an axial displacement of the pressure sleeve 20. The axial movement of the magnet 46 corresponds to the axial change in position of the pressure sleeve 20 relative to the preload element 64.The sensor unit 54, which is also arranged in the guide body 50, cooperates with the magnet 46 without contact and can detect the axial bearing change of the pressure sleeve 20.

[0069] The preload force acting on the packing 16 and the axial change in the force acting on the packing 16 can be derived from the axial displacement of the pressure sleeve 20 and the force-displacement characteristic of the spring element 22. This allows a position sensor value and the remaining preload force to be displayed and read at any time during operation. If the sensor value or the contact force reaches a predefined threshold, an alarm is triggered, for example, so that the packing 16 can either be reloaded or replaced due to wear.

[0070] In Fig. 6 is a perspective top view of the second embodiment of a control valve unit 10 according to the invention according to Fig. 5shown. The control valve unit 10 has a valve rod 12 sealed against a valve body 14 by means of a sealing arrangement. A packing 16 (not shown here) is provided, onto which a spring-loaded pressure sleeve 20 acts. The pressure sleeve 20 is acted upon by a pressure element 30, here designed as a compression flange, which cooperates with a spring element 22, which is supported on a prestressing element 64 of a prestressing device 24. The prestressing element 64, the spring element 22, and the pressure element 30 are penetrated by a connecting element 62 anchored in the valve body 14, which is here designed as a threaded bolt. By means of a screw nut 56 screwed to the connecting element 62, the tension force of the spring element 22 and thus the pressure application to the pressure sleeve 20 and the packing 16 can be varied.

[0071] The pretensioning device 24 is connected to a guide body 50 which forms an axial guide groove 48 in which a magnet 46 is mounted so as to be axially movable.

[0072] A sensor unit 54, which includes a magnetic sensor, is arranged in the guide body 50. The sensor and the magnet 46 are spatially separated from each other in the guide body 50. Due to the axial guidance of the magnet 46 in the guide groove 48, the magnet 46 always remains at a fixed radial distance relative to the fixedly mounted sensor unit 54.

[0073] In this case, the magnet 46 adheres to a magnetically conductive adhesive element 44, which is connected to a free end of the pressure sleeve 20 by means of a lockable fastening ring 42. The annular adhesive element 44 radially surrounds the valve rod 12. The adhesive element 44 penetrates radially at least partially into the guide groove 48 of the guide body 50. This allows the pressure sleeve 20 to axially entrain the magnet 46, which is connected to it in particular at the end, in the guide groove 48 when it moves axially due to wear of the packing 16. List of reference symbols

[0074] 10Control valve unit 12Valve rod 14Valve housing 16Packing 18Counter bearing 20Pressure sleeve 22Spring element 24Preload device 26Adjusting body 28Adjusting cover 30Pressure element 32Second stop 34Adjusting thread 36External thread 38Protrusion 40First stop 42Fastening ring 44Adhesive element 46Magnet 48Guide groove 50Guide body 52Measuring device 54Sensor unit 56Screw nut 58Cable connection 60Screw connection 62Connecting element 64Preload element

Claims

1. Control valve unit (10) with a measuring device (52), the control valve unit (10) comprising a valve rod (12) which is sealed off from a valve housing (14) via a sealing arrangement, the sealing arrangement having a packing (16) which is received axially between a pressure sleeve (20) and a counter-bearing (18) on the valve housing (14), which pressure sleeve (20) is axially mounted so as to be movable relative to the valve housing (14) and transmits a contact pressure applied to the pressure sleeve (20) by at least one spring element (22) to the packing (16), with the spring element (22) being supported on a pretensioning device (24) which is adjustable in terms of distance from the counter bearing (18), thus allowing an adjustment of the contact pressure of the spring element (22) acting on the pressure sleeve (20), and wherein the measuring device (52) senses a change in position of the pressure sleeve (20) relative to the counter-bearing (18), wherein the measuring device (52) has a sensor unit (54) for monitoring the contact pressure on the packing (16), which unit is connected to the pretensioning device (24), wherein the pressure sleeve (20) is axially movable relative to the pretensioning device (24), characterized in that the sensor unit (54) interacts with a magnet (46) which is connected to the pressure sleeve (20), the magnet (46) being arranged on the pretensioning device (24) in an axially guidable manner, and the measuring device (52) having a guide body (50) which is connected to the pretensioning device (24) and forms an axial guide groove (48) in which the magnet (46) is arranged in a manner to prevent it from falling out.

2. Control valve unit according to claim 1, characterized in that the sensor unit (54) is arranged on the guide body (50).

3. Control valve unit according to any one of the preceding claims, characterized in that the magnet (46) is arranged to be rotatable in the circumferential direction of the valve rod (12).

4. Control valve unit according to any one of the preceding claims, characterized in that the magnet (46) is connected to the pressure sleeve (20) via a magnetically conductive adhesive member (44).

5. Control valve unit according to claim 4, characterized in that the adhesive member (44) is connected to the pressure sleeve (20) via a fastening ring (42).

6. Control valve unit according to any one of claims 4 or 5 above, characterized in that the adhesive member (44) engages radially around the valve rod (12).

7. Control valve unit according to any one of claims 4 to 6 above, characterized in that the adhesive member (44) penetrates at least partially radially into the guide groove (48) of the guide body (50), thereby entraining the magnet (46) in the axial direction.

8. Control valve unit according to any one of the preceding claims, characterized in that the sensor unit (54) is connected to a control unit for communication which latter determines the contact pressure on the packing (16) via a force-displacement characteristic of the spring element (22).

9. Control valve unit according to claim 8, characterized in that the control unit is connected to an operating unit for communication, which operating unit has at least one display unit and a calibration button.

10. Control valve unit according to any one of claims 8 or 9 above, characterized in that the control unit for adjusting the contact pressure is connected to at least one actuator that is in turn connected to the pretensioning device (24).