CN211265153U

CN211265153U - Solenoid valve and electronic control device for operating a solenoid valve

Info

Publication number: CN211265153U
Application number: CN201921927966.4U
Authority: CN
Inventors: S·科尔本施拉格; T·韦策尔; L·尤斯弗
Original assignee: Hercules Corp
Current assignee: Hercules Corp; Samson AG
Priority date: 2018-11-09
Filing date: 2019-11-08
Publication date: 2020-08-14
Anticipated expiration: 2029-11-08
Also published as: EP3877683A1; DE102018008846A1; WO2020094885A1

Abstract

The application provides a solenoid valve and an electronic control device for operating the solenoid valve. Solenoid valve, in particular for an electropneumatic drive, in particular for use in a process production plant, comprising: a magnetic coil, in particular annular; a magnetic armature which accommodates the magnetic coil and is made of magnetizable material and on the inside of which an armature is movably arranged and the outside of which at least partially surrounds the magnetic coil; a magnetic field sensor, in particular a Hall sensor, for detecting, in particular for measuring, a magnetic flux density, wherein a contour discontinuity, such as a contour recess, for example a groove, is formed on an outer side of a magnetic ground, wherein the magnetic field sensor is arranged in the region of the contour discontinuity.

Description

Solenoid valve and electronic control device for operating a solenoid valve

Technical Field

The present invention relates to a solenoid valve, in particular for an electropneumatic drive, which is used in particular in process production plants, such as chemical or petrochemical plants, food processing plants, nuclear power plants or other process production plants. The pneumatic drive can be used, for example, to operate an adjusting device, such as a regulating valve. The utility model discloses still relate to an electronic control device and solenoid valve control method for controlling the solenoid valve.

Such a solenoid valve may be equipped with a sensor for determining the armature position in such a solenoid valve. Furthermore, the invention also relates to a solenoid valve control method and a position regulator, in particular an electro-pneumatic position regulator, which can be operated according to the method according to the invention and/or comprises a solenoid valve according to the invention. Such a position regulator can be combined with a pneumatic drive for operating a field instrument (e.g., a regulator valve or an emergency shut-off valve) of a process plant.

Background

Solenoid valves are typically operated by electromagnets. Solenoid valves of this type have, in particular, a ring-shaped magnet coil, the inductance of which generates a magnetic field which can cause the armature of the solenoid valve to be displaced, preferably in the form of a translatory adjustment movement. It is known that the armature of a solenoid valve moves into the moved-in position when energized, and moves out in the absence of a magnetic field. Depending on the position of the armature, the solenoid valve opens or closes. The coil is usually wound around a central portion or core of the solenoid valve, the so-called magnetic ground. The movable armature is usually ferromagnetic and is attracted by a magnetic field which is generated by a coil and is intensified by a magnetic core. The magnetic field formed between the armature and the core exerts a force which depends, in particular, on the air gap formed between the armature and the magnetic core. The smaller the distance between the core and the armature, the stronger the magnetic force. The solenoid valve is usually provided with a valve seat which cooperates with a core part connected to the armature in such a way that it opens and/or at least partially seals a channel or path in the valve body in one or more positions of the core part.

DE 102015116464 a1 discloses a solenoid valve having a magnetic sensor for measuring the magnetic flux and thus for calculating and regulating the force acting on the armature. The solenoid valve has a magnetic field sensor, in particular a hall sensor, for measuring the magnetic flux density, which sensor is arranged in the air gap between the armature and the magnet core. The air gap is formed in the magnetic ground on the radially inner side with respect to the solenoid valve annular coil accommodated in the magnetic ground. A hollow cylindrical bridge which forms part of the outer section of the magnetic contact of the solenoid valve is inserted partially in the air gap. Because of the magnetizable bridge, a part of the magnetic field is guided through the air gap, the flux density of which is approximately that of the air gap between the core and the armature. By measuring the magnetic field, the magnetic ground can deduce the force acting on the armature.

The solenoid valves described above require special complex housings or magnetic grounding structures, in particular around the bridge, which is inserted into the annular cylindrical cavity to form a sufficient measuring air gap.

In order to operate the above-described or other similar types of solenoid valves, a unique, in particular highest, electrical power is required to energize the coil. The magnetic armature is set in motion after overcoming the static friction and is held in the switched-on state with the application of a current (peak current, pull-in current). The highest power is always required at this time, although the highest power is not required to hold the magnetic armature.

SUMMERY OF THE UTILITY MODEL

The object of the present invention is to overcome the disadvantages of the prior art and in particular to provide a solenoid valve which operates in a high-performance manner and in particular reliably detects an incorrect position of the solenoid valve without having to change the basic structure of the solenoid valve.

According to a first aspect of the present invention, a solenoid valve is proposed, in particular for an electropneumatic drive, in particular for use in a process production plant.

According to the utility model discloses a solenoid valve especially has the function of the solenoid valve of direct action. The solenoid valve is operated by an electromagnet. By applying a voltage, the coil is energized and generates a magnetic field which attracts an armature fixed to the valve stem, thereby opening or closing the valve. The valve seat is designed in particular such that it opens and seals a corresponding passage in the valve body in the two end positions.

The solenoid valve according to the invention comprises a, in particular, annular magnet coil and a magnet armature which accommodates the magnet coil, on the inner side of which an armature is movably mounted, in particular supported, and which at least partially surrounds the magnet coil and/or which at least partially covers the magnet coil. The magnetic ground delimits a particularly cylindrical cavity, and the armature can be moved back and forth along a linear adjusting movement, for example like a plunger. Magnetic grounds may also be referred to as magnetically permeable grounds. The coil may also be referred to as a winding or an inductor. According to the utility model discloses a solenoid valve still has magnetic field sensor, especially hall sensor, hall switch sensor or reed contact for detect especially measure magnetic flux density. According to the invention, a contour jump, such as a contour recess, for example a groove, is formed on the outer side of the magnetic ground, wherein the magnetic field sensor is arranged in the region of the contour jump. The abrupt contour forms in particular a weakening of the magnetizable material of the magnetic circuit, as a result of which the magnetic resistance of the magnetic circuit is increased in the magnetic circuit. In a defined energized state of the coil, the field lines can penetrate outside the magnetic ground in the region of the abrupt contour. This makes it possible, when a certain excitation current is applied to the magnetic coil, to derive the size of the so-called working air gap between the armature and the magnetic ground and in particular its central core, as a result of the magnetic field sensor located in the region of the profile discontinuity, which working air gap increases and decreases during operation of the solenoid valve. The magnetic field sensor detects the magnetic flux in the region of the abrupt contour change, in particular in the recess of the contour, in order to determine, in particular, the armature position.

When the armature, for example, falls, the total magnetic resistance increases and the magnetic field strength in the recess decreases with the excitation current remaining constant, which is detected by the sensor. From this, the armature position can be deduced. The sensor therefore detects whether the armature is engaged under the application of a voltage. In the recess, the sensor therefore detects the strength of the stray field via the slot air gap or changes a predeterminable initial state when a switching threshold is undershot/exceeded. Thus, the sensor can distinguish between an "armature pull-in" state or an "armature drop" state and output a corresponding electrical signal obtained by the control unit.

In a preferred embodiment of the invention, the abrupt contour change is designed as a contour recess, such as a groove. The contour recess is preferably formed in an especially even outer lateral surface of the magnetic ground body. For example, the outer magnet contact surface is an outer end surface which lies flat and/or perpendicular to the armature displacement direction, or a peripheral surface which is in the form of a circle of revolution, in particular cylindrical, which particularly preferably completely surrounds the magnet coil. The groove preferably has a radial or axial profile depth of less than 20 mm or 10 mm, in particular a profile depth of more than 50%, 60%, 70%, 80% of the wall thickness of the magnetic ground of the coil.

An air gap is preferably formed between the magnetic field sensor arranged in the contour recess and the wall of the contour recess. The walls of the contour recess are defined, in particular, by wall portions, for example, by side walls or a base of the recess, in particular blind-hole-shaped and/or circumferential, on the outer side of the magnetic ground. In particular or alternatively, the contour recess is provided in the form of a blind hole and/or circumferentially in the magnetic ground, and/or the measuring point of the magnetic field sensor is provided in the contour recess. The contour recess preferably has a depth, measured from the outer side of the magnetic ground, such as the end face or the cylindrical circumferential side, the dimensions of which are selected such that the structural extension of the magnetic field sensor and/or the optimum measuring point determined by the magnetic field sensor is arranged completely within the contour recess. The magnetic field sensor is preferably arranged in such a way that the magnetic field sensor, and in particular its structural dimensions, project into the contour recess.

The magnetic field sensor is preferably designed to detect exceedance and/or undershooting of a predetermined magnetic field strength, for example a solenoid valve switching threshold (armature pull-in/armature drop), so that, as the case may be, a corresponding status signal (for example an exceedance signal or undershoot signal) can be sent, in particular, to an electronic control unit which preferably causes the energization of the magnetic coil. The electronic control device can be, for example, a superordinate central control unit or a solenoid valve-specific microcomputer unit, which is connected directly to the magnetic field sensor. The electronic control means may form part of the solenoid valve arrangement. The electronic control device may comprise a circuit board on which the electronics and/or the magnetic field sensor are fastened, wherein in particular the longitudinal extension of the circuit board may be selected such that the circuit board can protrude in the contour recess beyond the outer side of the magnetic ground.

In a development of the invention, the magnetic field sensor is designed to determine the position of the armature, in particular along its translational adjustment path, as a function of the magnetic flux in the region of the abrupt change in contour. The magnetic field sensor can function as a position sensor that can communicate with a position adjustment device (e.g., a position adjuster).

In a preferred embodiment of the invention, the solenoid valve according to the invention has an electronic control unit, which is constructed and/or designed, in particular according to the invention which will be described further below, to output a pull-in current or a holding current as an excitation current to the magnet coil, wherein the pull-in current is set, in particular, in such a way that the armature moves into a final position, in particular in a shift-in position. The electronic control unit is preferably designed to output a holding current as an excitation current to the magnet coil as soon as the armature is in the in particular moved-in final position, wherein in particular the holding current is set such that the holding current is lower than the pull-in current and/or the armature is held in the in particular moved-in final position.

The magnetic ground is made of a magnetizable material, preferably a ferrite material. In one example, the magnetic ground has a circumferential receiving body for receiving the magnet coil and a core which is arranged substantially axially diametrically opposite the armature and which is formed along the axis of symmetry of the magnetic ground or the axis of translational movement of the armature and/or on which the armature bears or bears in particular in one of the end positions of the solenoid valve.

According to a preferred embodiment, the armature is connected to the core of the magnetic ground by a spring element, wherein the working air gap is formed between the armature and the core. The size of the working air gap varies as the armature moves into and out of the space. The armature is urged to the removed position by a spring member in the absence of an applied magnetic field. The armature is moved into the retracted position when a magnetic field is applied. In one example, the armature can be moved in translation from the moved-in position to the moved-out position in the longitudinal direction of the armature and/or along the axis of symmetry of the solenoid valve. In one example, the armature operates a spool piece (closing member) of the regulator valve.

According to a further preferred embodiment, the solenoid valve has an electronic control device which is designed to output a pull-in current or a holding current as an excitation current to the magnet coil, wherein in particular the pull-in current is set in such a way that the armature is moved into the final position, in particular moved in. The electronic control unit can preferably be designed to output a holding current as an excitation current to the magnet coil as soon as the armature is in the in particular moved-in final position, wherein in particular the holding current is set such that it is lower than the pull-in current and/or the armature is held in the in particular moved-in final position.

The electronic control unit regulates the excitation current in such a way that the respective required current is applied to the coil for the purpose of engaging and for the purpose of reliably holding the armature. This can reduce the power consumption of the solenoid valve. Since the magnetic air gap is already reduced after the valve has been switched into the first position, the magnetic resistance of the magnetic circuit is thereby also reduced, the reduced current or the reduced magnetic field being sufficient to hold the armature in the moved-in position. The current is regulated to a lower holding current after a prescribed time, thereby reducing power consumption. However, there is the danger that, as a result of external forces (for example impacts/accelerations in the form of impact on the solenoid valve or as a result of vibrations in the line), the armature may fall in the holding state due to the excessively low attracting magnetic force and reach an undesired valve seat position, which is detected by the solenoid valve described above. After the armature is found to drop, the armature can be pulled back again with higher power to suppress the undesirable effect of the armature drop.

According to a further preferred embodiment, the recess is dimensioned such that, when the armature is held in the retracted position, the magnetic and preferably ferrous magnetic contact is in a magnetically saturated state, preferably slightly beyond the saturation state limit, in the region of the recess when the excitation current is applied. The saturation state of the magnetic ground indicates a state in which a part of the magnetic field lines penetrates the magnetic ground material. In the case of magnetic saturation, the field strength in the region of the recesses is, for example, in the range from 6 to 15mT, in particular from 10 to 15mT, preferably from 12 to 14 mT.

According to one embodiment, the magnetic field sensor is designed to detect a saturation state in the recess and to output a first signal, so that the armature is in the retracted position in the pull-in state or the holding state. According to one embodiment, the sensor is also designed to detect that the recess is not in a saturated state and to output a second signal, i.e. the armature falls toward the moved-out position, in particular because of a malfunction or malfunction of the solenoid valve.

With a reduced holding current compared to the pull-in current, the armature can fall from the retracted position due to a too low pull-in magnetic force. The fall may be caused, for example, by external forces (e.g., impact, vibration of the pipeline). When the armature leaves the core (i.e., falls) while the holding current remains constant, the air gap between the core and the armature increases. The increase in the air gap causes an increase in the total reluctance of the magnetic circuit. This means that the magnetic flux passing through the groove area is not large. The magnetic material of the magnetic ground is now no longer in saturation and can completely conduct the required magnetic flux. The field line intensity is thus reduced in the gas region of the groove, for example to the range of 1-5 mT, in particular 1-3 mT. The armature state "pull-in" or "drop-down" may also be indicated by a display element (e.g., an LED). In addition, the signal can also be transmitted to the console in order to check the cause of an undesired armature drop in situ, if necessary.

Furthermore, the present invention also relates to an electronic control device for operating an above-mentioned solenoid valve, in particular for an electro-pneumatic drive device, in particular for use in a process production plant. The solenoid valve can be placed in an open-on state and a closed-on state. The electronic control device according to the invention comprises a power supply output for applying an excitation current to the solenoid valve coil in order to place the solenoid valve from the closed-switched state into the open-switched state. In order to apply a supply voltage to the electronic control unit, the electronic control unit may also have a supply input, which is also used in particular for supplying electronic components of the electronic control unit. The electronic control device according to the invention also has a switching regulator for regulating the excitation current at the coil, wherein the switching regulator is designed to load a pull-in current on the solenoid valve coil when placed in the open-closed state and to load a holding current on the coil for the purpose of subsequently maintaining the open-closed state, the holding current being lower than the pull-in current. The control variable of the switching regulator can be, for example, the magnetic flux density, the magnetic resistance of the magnetic circuit, etc., which can be determined and used, in particular, by a magnetic field sensor.

In a preferred embodiment of the invention, the electronic control device can have a sensor and in particular a magnetic field sensor for detecting whether the solenoid valve has reached a specific switching state, for example an open-switching state, wherein the sensor is supplied with power by an input voltage applied to the electronic control device and/or the sensor is arranged in a recess (for example a groove) of a metal body of a magnetic ground (for example a yoke), and/or a circuit board comprising power electronics for a switching regulator, wherein the magnetic sensor is arranged on the circuit board in a recess (for example a groove) of a metal body of a magnetic ground (for example a yoke), wherein in particular the sensor is also arranged on the circuit board. The groove is preferably formed circumferentially.

According to another embodiment, the electronic control device has a resistor (preferably a shunt resistor), a comparator and a transistor (preferably a MOSFET) for adjusting the excitation current in the coil to the holding current. At this time, a resistance in series with the coil may generate a voltage drop proportional to the excitation current. When the pull-in current is applied as the excitation current, the voltage drop at the resistor reaches a threshold value, wherein the threshold value can be determined in a comparator. The comparator switches off the flow of current in the coil through the transistor to ground when the threshold is reached. A freewheeling diode connected to the coil dissipates current in the coil when the comparator disconnects the flow of current. The transistor is switched on autonomously after a defined time, preferably in the range of a few milliseconds, so that the current from the coil to ground increases again and is switched off again by the comparator when the threshold value is reached. The threshold value can be set in the comparator to a smaller threshold value for the adjustment from the pull-in current to the holding current, so that the excitation current in the coil can be set to the desired holding current.

The electronic control device may also be referred to as a power electronics. The control unit applies an attraction current to the coil until the armature changes its state and the sensor outputs a state signal of 'armature attraction'. The pull-in current may also be referred to as the peak current. If the armature is pulled in, the control unit reduces the current after a certain time and applies a holding current to the coil. The holding current may also be referred to as a holding current (Hold-from). By monitoring the armature position and adjusting the coil current to a low level, significant energy savings can be achieved without compromising normal valve operation.

According to a further embodiment, the electronic control unit is designed in such a way that it receives a second signal from the magnetic field sensor when the armature falls undesirably, wherein the control unit then changes the threshold value in the comparator in such a way that the coil can be excited with the pull-in current and the armature can be pulled into the retracted position again.

At the same time, electronic wiring of the electronic control device can also be carried out in order to evaluate the sensors as described above. If the magnetic field sensor emits a second signal "armature falls", the electronic device increases the threshold voltage of the comparator to the pull-in current and thereby effects a transition of the armature to the state "armature pull-in".

According to a further embodiment, the electronic control unit is designed such that when the pull-in current is detected and a second signal from the sensor is obtained, the armature is signaled in the latched position.

For example, a complete armature stroke cannot be performed because of foreign bodies in the valve and the flow region or because of seal failure or material wear, in particular wear, jamming or jamming. Furthermore, the armature travel can be continuously increased by means of the above-described detection of the pull-in current and evaluation of the sensor signal. The intermediate position can thus be detected and a further conclusion of the position of the valve stem can be obtained. For example, a fault situation may prevent the entire reliable valve travel, and thus the opening or closing of the valve cone on the valve seat. As a result, in particular in safety-relevant applications, a corresponding safety position cannot be guaranteed and dangerous situations can occur. By detecting different armature positions, the exact valve position can be ascertained and reported to the user/operator as a fault situation if necessary.

According to one embodiment, the sensor is a magnetic field sensor, preferably a hall sensor or a hall switch sensor or a reed contact.

In order to detect the armature drop, i.e. the field strength from a slightly saturated state to an unsaturated state, a hall switch sensor can be used, for example, which has a defined switching threshold between the states "armature pull-in" and "armature drop", preferably between 13.6 and 1.7mT, preferably centered at 7.6 mT.

According to one embodiment, the control circuit board of the electronic control unit directly accommodates the magnetic field sensor. The magnetic field sensor is arranged such that it protrudes into the recess. It is thereby possible to arrange the sensor directly on the outer side of the solenoid valve and directly on the control circuit board of the electronic control unit without additional connecting elements. At this time, the sensor is powered by the input voltage, for example, like a control unit. Therefore, the complicated shell structure and the wire penetrating hole in the electromagnetic valve can be avoided.

Finally, the invention relates to a method for controlling the above-mentioned solenoid valve, in particular according to the invention, for example for an electropneumatic drive, which is used in particular in a process production plant. In this method, the solenoid valve can be placed in either an open-switch state or a closed-switch state. In order to put the solenoid valve from the closed-open state into the open-open state, a pull-in current is applied to the coil of the solenoid valve. In the open-switch state, the pull-in current remains loaded on the coil for the pull-in time length and after the pull-in time a holding current is loaded on the coil, which holding current is lower than the pull-in current.

In a preferred embodiment of the invention, during the loading of the holding current on the coil, the open-closed state of the solenoid valve is monitored by means of a sensor and preferably a magnetic field sensor to see whether the solenoid valve leaves the open-closed state or not, and if the solenoid valve should leave the open-closed state, a pull-in current is loaded on the coil, wherein the leaving of the solenoid valve-specific open-closed state is determined in particular by detecting an increase in the magnetic resistance of the magnetic metal circuit in the region of the magnetic ground of the solenoid valve, in particular in the region of a weakening (e.g. a recess, for example a groove) of the magnetic ground metal body.

In a further development of the method according to the invention, it can be provided that the holding current is only applied when a specific switching state and preferably an open-closed state of the solenoid valve is reached, wherein it is detected, in particular by means of a sensor, in particular a magnetic field sensor, whether the specific switching state is reached, which in particular enables a detection of a leakage magnetic field strength at the outer side of the magnetic ground metal body of the solenoid valve, and/or that, in the case of an applied holding current, the attracting current is applied again to the coil when a deviation, in particular predetermined, is detected, in particular by a sensor, such as a magnetic field sensor, with respect to the specific switching state and preferably the open-closed state of the solenoid valve.

According to another aspect of the present invention, a method for controlling a solenoid valve according to the present invention is provided, comprising the steps of: the solenoid valve is operated with a pull-in current to move the armature into the move-in position. The solenoid valve is operated by a holding current to hold the armature in the moved-in position, wherein the holding current is lower than the pull-in current. The current is regulated depending on how the armature is positioned relative to the magnetic ground core and/or how the magnetic field sensor determines the armature position.

According to another embodiment, the method further has the steps of: the movement of the armature into the engaged or held position is detected by a sensor, preferably a magnetic field sensor, and a first signal is output.

According to another embodiment, the method further has the steps of: the drop of the armature toward the moved-out position is detected by the sensor, and then a second signal is output.

According to another embodiment, the method further has the steps of: the pull-in current is applied by the control unit, so that the coil can be excited by the pull-in current and the armature is pulled back into the retracted position. The solenoid valve is operated with a holding current to hold the armature in the first position.

According to another embodiment, the method further has the steps of: the control unit detects whether the pull-in current and the second signal exist or not, and informs the armature of being in the locking position according to the signals.

In another example, the solenoid valve can also function as a vibration meter, in that the armature-spring element unit is considered as a spring-mass system, and a sensor, preferably a hall sensor, is used to detect vibrations, while a control unit is used to process/convert the signals and is also used for signal analysis.

Drawings

Other features, characteristics and advantages of the present invention will become apparent from the description of preferred embodiments of the present invention, given with reference to the accompanying exemplary drawings, in which:

figure 1a shows a schematic cross-sectional view of a solenoid valve according to an embodiment of the present invention,

figure 1b shows a schematic cross-sectional view of a solenoid valve according to another embodiment of the present invention,

fig. 2a and 2b show schematic diagrams of the course of the magnetic field lines in a magnetic ground having abrupt contour changes, according to one embodiment.

List of reference numerals

9 end face

10 solenoid valve

12 armature

14 magnetic earth

16 core part

17 recess

18 magnetic coil

19 compression spring

20 groove

21 circumferential side

22 magnetic field sensor

23 guide cylinder

25 reel body

26 shunt resistor

28 comparator

30 freewheeling diode

31 pneumatic input

32 transistor

33 pneumatic output

35 valve core piece

36 control logic circuit

40 electronic circuit board

Detailed Description

Fig. 1a to 1b show a solenoid valve 10, which comprises a magnetic earth 14, which may be formed in particular by a cup-shaped iron body, in the center of which a cylindrical guide is formed, in which an armature 12 is movably arranged. The magnetic ground 14 has a substantially flat end face 9 and a cylindrical circumferential side (21 coils).

A recess 17 is formed in the central core 16 of the iron body, in which recess a compression spring 19 is seated. The compression spring 19 is inserted into a recess formed in the armature 12 and is thus firmly mounted in the radial direction. The compression spring 19 forces the armature 12 out of the final position, which is not shown in fig. 1a and 1 b.

The magnetic ground 14 comprises a hollow space, in particular in the form of a ring, in which a radially outwardly open reel body 25 is accommodated, which accommodates the magnetic coil. In the axial direction, the coil extends along a substantial portion of the core 16 and overlaps the armature 12 throughout its axial working range.

The outer surface of the spool body 21 (and also the inner side of the magnetic armature 14) defines at least in part a guide cylinder 23 in which the armature 12 can be moved in and out.

A working air gap 25 is formed between the armature 12 and the core 16 of the magnetic ground 14. When an excitation current is supplied to the magnet coil 18, a magnetic force occurs which causes the armature 12 to be drawn from its final position, in which the armature 12 is forced by the compression spring 19, into the moved-in final position shown in fig. 1a and 1 b.

The solenoid valve 10 according to the invention has a pneumatic input 31 and a pneumatic output 33, which can be opened or closed by means of a valve core part 35. In the final position as shown in fig. 1a and 1b, the pneumatic communication between the channel 31 and the channel 35 is interrupted. This end position is fixed by the opposing valve seat stop. The core member 35 is fixedly connected to the armature 12, in particular made of one piece of magnetizable material.

An electronic control device, which is not shown in detail in fig. 1a and 1b, energizes the coil 18, whereby pneumatic inputs/outputs (31,33) can be supplied. The electronic control device, which is not shown in detail, can be part of a pneumatic position regulator, which is part of a pneumatic drive of the process plant.

On the outer side of the magnetic contact 14, i.e. the end face 9, there is formed a profile transition in the form of a groove 20, which according to fig. 1a extends concentrically to the longitudinal axis a of the translational movement of the armature 12. The groove 20 is formed circumferentially.

According to the embodiment of fig. 1b, a circumferential groove 20 can also be formed on the circumferential side of the magnetic ground 14. In both embodiments, the groove 20 forms a weakened portion of the metal body of the magnetic earth 14. For this reason, the magnetic resistance in the magnetic ground 14 is increased.

A magnetic field sensor 22 is positioned in the slot 20. The sensor 22 senses the magnetic flux within the slot 20 to determine the position of the armature 12. In one example, the channel 20 is a groove having a rectangular cross-section with opposing sidewalls and a bottom. As shown in fig. 1a and 1b, there is an air gap between the sensor and one of the side walls and the bottom. Other grooves are also conceivable, such as for example arc-shaped grooves.

As shown in fig. 1a and 1b, the armature 12 is connected to the core 16 of the magnetic ground 14 by a compression spring 19, wherein a working air gap 25 is formed between the armature 12 and the core 16. The magnetic ground 14 is designed, for example, as a housing that encloses the coil 18 and the armature 12. The core 16 is preferably formed as an integral part of the magnetic armature 14 and is arranged along the axis of symmetry a of the solenoid valve 10. The core 16 is formed as a section of the magnetic contact 14 that projects into the armature 12. One end face of the armature 12 is opposite to the end face of the core 16 and is aligned along the axis of symmetry of the solenoid valve. The size of the working air gap 25 changes as the armature 12 moves partially into and out of the space defined by the magnetic ground 14. The armature 12 is forced into the extended position by the spring element 19 without the application of a magnetic field. The armature 12 is adjusted to the retracted position with the magnetic field applied.

In one example, the armature 12 may translate from the in-position to the out-position along a longitudinal direction of the armature and/or along an axis of symmetry of the solenoid valve. In one example shown here, the armature 12 operates a core piece 35 (closing part). A closing part directly coupled to the magnetic armature is drawn upwards and closes the upper valve seat (here, for example, a two-position three-way valve). When the field current is switched off, no magnetic field is present, the spring element 19 presses the armature 12 back into its initial position, for example the extended position, and the closing element 35 closes off its lower valve seat.

In a preferred embodiment, the solenoid valve 10 has electronic control means. The electronic control device is designed such that a pull-in current or a holding current is output to the coil 18 as an excitation current. The pull-in current is defined to move the armature 12 into the moved-in position. The holding current after the armature 12 is in the moved-in position is set to hold the armature 12 in the moved-in position. Wherein the holding current is lower than the pull-in current. The electronic control unit sets the field current in such a way that the respective required current is applied to the coil 18 for the purpose of engaging and also for the purpose of securely holding the armature 12. This can reduce the power consumption of the solenoid valve 10.

According to another embodiment, the electronic control device 24 has, as shown in fig. 2a and 2b, a resistor 26 (preferably a shunt resistor), a comparator 28 and a transistor 32 (preferably a MOSFET) to regulate the excitation current in the coil 18 to a holding current. Wherein a resistor 26 in series with the coil 18 may generate a voltage drop proportional to the field current. When the pull-in current is applied as the excitation current, the voltage drop at the resistor 26 reaches a threshold value t, which can be determined in the comparator 28. When this threshold value is reached, comparator 28 switches off the flow of current in coil 18 to ground via transistor 32. When the comparator 28 disconnects the flow of current, the freewheeling diode 30 connected to the coil dissipates the current in the coil 18. The transistor 32 is switched on autonomously after a defined time, preferably in the range of a few milliseconds, so that the current flow from the coil 18 to earth is increased again and interrupted again by the comparator 28 when the threshold value is reached. The threshold value can be set to a smaller threshold value in the comparator 28 in order to set the pull-in current to the holding current, so that the excitation current in the coil 18 can be set to the desired holding current.

The electronic control device 24 may also be referred to as power electronics. The electronic control unit 24 here follows a switching logic which applies a pull-in current to the coil 18 until the armature 12 switches its state and the sensor 22 outputs a state signal "armature pull-in" to a control logic 36 (for example a microcomputer). The pull-in current may also be referred to as the peak current. If the armature 12 is pulled in, the electronic control unit 24 reduces the current after a certain time and applies a holding current to the coil. The holding current may also be referred to as a holding current. By monitoring the armature position and adjusting the coil current to a low level, significant energy savings can be achieved without compromising normal valve operation.

The operating principle of peak current and holding current is based on the switching regulator type "step-down transformer". A shunt resistor 26 in series with the coil 34 produces a voltage drop proportional to the field current. If the excitation current in the coil 18 increases after the supply voltage has been applied, the voltage drop at the shunt resistor 26 reaches a certain upper limit, which is determined and detected by the comparator circuit. Comparator 28, when the threshold is reached, disconnects the flow of current through coil 18 by means of transistor 32 or an electronic switch, such as a MOSFET switch. Since the current flowing through the coil 18 does not suddenly stop, it is also purposefully further conducted through the freewheeling diode 30. After a defined time of a few milliseconds, the control logic 36 of the electronic control unit 24 switches the electrical switch back on and the current in the coil 18, which then flows through the freewheeling diode 30, flows back to ground. The current thus increases until the voltage at the shunt resistor 26 reaches the comparator threshold voltage and the MOSFET is again disconnected from ground. The process is now repeated, whereby the current in the coil 18 is kept at a constant current with ripple.

By varying the threshold voltage of the comparator, the magnitude of the coil current or the excitation current can be varied during operation of the valve 10. If the threshold voltage of the comparator 28 is lowered, the electronic control device 24 effectively regulates out the lower current in the coil 18. By means of the smart wiring, it is possible to achieve a setting of the pull-in current (peak current) after the initial energization of the circuit, which leads to a reliable transition of the valve armature 12 to the "armature pull-in" state. If this state is reached after a certain time, the electronic control unit 24 purposefully reduces the current to the holding current, as a result of which the power drawn by the coil 18 is reduced.

At the same time, electronic wiring of the electronic control device 24 can also be carried out in order to evaluate the sensor 22 as has been described previously. If the sensor 22 sends a second signal "armature down" to the control logic 36, the electronics increase the threshold voltage of the comparator 28 to the pull-in current and thus effect the transition of the armature 12 to the "armature pull-in" state.

According to a preferred embodiment, the control circuit board of the electronic control device 24 directly houses the magnetic field sensor 22. The magnetic field sensor 22 is arranged such that it protrudes into the slot 20, as schematically shown in fig. 1 a. It is thereby possible to arrange the sensor 22 directly on the outer side of the solenoid valve 10 and directly on the control circuit board 40 of the electronic control unit 24 without additional connections. The sensor 22 is supplied with power via an input voltage, for example, like an electronic control unit 24. This avoids complex housing structures and passages for electrical lines to pass through the solenoid valve 10.

According to a further aspect of the present invention, a method for adjusting a solenoid valve 10 is proposed, having the following steps: the solenoid valve 10 is operated with a pull-in current to move the armature 12 to the moved-in position. The solenoid valve 10 is operated with a holding current to hold the armature 12 in the moved-in position, wherein the holding current is lower than the pull-in current.

According to another embodiment, the method further has the steps of: the armature 12 is detected in the moved-in position in the engaged or held state by a sensor, preferably a magnetic field sensor 22, and a first signal is output.

According to another embodiment, the method further has the steps of: the drop of the armature 12 toward the moved-out position is detected by the sensor, and then a second signal is output.

According to another embodiment, the method further has the steps of: the pull-in current is applied via the electronic control unit 24, so that the coil 18 can be excited by the pull-in current and the armature 12 is pulled into the retracted position again. The solenoid valve 10 is operated with a holding current to hold the armature 12 in the first position.

According to another embodiment, the method further has the steps of: the presence of the pull-in current and the second signal are detected by the electronic control unit 24 and the armature is signaled in this way to the latched position.

In another example, the solenoid valve 10 can also function as a vibration meter, in that the armature-spring element unit is considered as a spring-mass system, and a sensor, preferably a hall sensor, is used to detect vibrations, while a control unit is used to process/convert the signals and also to analyze the signals.

The above embodiments can be combined in different ways. In particular, the method variant can also be used for the embodiment of the device and for the use of the device, and vice versa.

It is also noted that "comprising" does not exclude other elements or steps and "a" or "an" does not exclude a plurality. The features disclosed in the foregoing description, in the drawings and in the claims are of significance both individually and in any combination for the realization of the invention in different embodiments.

Claims

1. A solenoid valve (10) for an electropneumatic drive for use in a process production plant, the solenoid valve comprising:

a magnetic coil (18) in the shape of a ring;

a magnetic armature (14) made of magnetizable material, which accommodates a magnetic coil (18), on the inner side of which an armature (12) is movably arranged and the outer side of which at least partially surrounds the magnetic coil (18);

a magnetic field sensor (22) for detecting a magnetic flux density;

the magnetic field sensor is characterized in that a profile jump is formed on the outer side of the magnetic ground (14), wherein the magnetic field sensor (22) is arranged in the region of the profile jump.

2. The solenoid valve (10) of claim 1, wherein the magnetic field sensor (22) is a hall sensor.

3. The solenoid valve (10) according to claim 1, characterised in that the abrupt contour change is designed as a contour recess, wherein an air gap is present between the magnetic field sensor (22) arranged in the contour recess and the wall of the contour recess, and/or the contour recess is blind-bored and/or is arranged circumferentially in the magnetic ground (14), and/or a measuring point of the magnetic field sensor (22) is arranged within the contour recess, wherein the magnetic field sensor (22) is arranged such that it projects into the contour recess.

4. The solenoid valve (10) of claim 3, wherein the contoured recess is a groove (20).

5. The solenoid valve (10) according to claim 3, characterised in that the magnetic field sensor (22) is designed to detect a magnetic field strength above and/or below a predetermined value, so as to be able to send a corresponding status signal to the electronic control device (24) which causes the magnetic coil (18) to be energised; and/or

The magnetic field sensor is designed to determine the position of the armature (12) along a translational adjustment path of the armature (12) as a function of the magnetic flux in the region of the contour recess.

6. The solenoid valve (10) according to claim 5, characterized in that the magnetic field sensor (22) is designed to detect an increase and/or a decrease above and/or below a solenoid valve switching threshold.

7. The solenoid valve (10) according to claim 1, characterised in that the armature (12) is supported on the magnetic contact (14) by a spring element (19) and in the final position of the solenoid valve (10) a working air gap (25) is formed between the armature (12) and a core (16) of the magnetic contact (14), the size of which varies as the armature (12) moves in and out in the translational adjustment direction (a); and/or

Wherein the armature (12) is forced to the moved-out final position by a spring element (19) without application of a magnetic field;

wherein the armature (12) is magnetically attracted by the core (16) into the retracted position under the application of a magnetic field.

8. The solenoid valve (10) according to one of the preceding claims, comprising an electronic control device (24) which is designed to output a pull-in current or a holding current as excitation current to the magnet coil (18), wherein the pull-in current is set in such a way that the armature (12) is moved into the moved-in final position;

wherein the electronic control device (24) is designed to output a holding current as an excitation current to the magnet coil (18) as soon as the armature (12) is in the moved-in final position, wherein the holding current is set in such a way that it is lower than the pull-in current and/or the armature is held in the moved-in final position and/or

The control circuit board of the electronic control device (24) directly accommodates the magnetic field sensor (22).

9. The solenoid valve (10) according to claim 1, characterized in that the abrupt contour change is dimensioned in such a way that the magnetic ground (14) is in a state of magnetic saturation in the region of the abrupt contour change when an excitation current is applied, in order to bring or hold the armature (12) into or in the moved-in or moved-out end position.

10. The solenoid valve (10) according to claim 1, characterized in that the abrupt contour change is dimensioned in such a way that the magnetic contact (14) in the region of the abrupt contour change slightly exceeds the limit of the saturation state when an excitation current is applied.

11. The solenoid valve (10) according to claim 9, characterised in that the magnetic field sensor (22) is designed to detect the saturation state in the profile jump and to output a first signal in order to signal the moving position of the armature (12) in the engaging or retaining state and/or

The magnetic field sensor (22) is designed to detect whether a saturation state exists in the region of the abrupt profile change and to output a second signal in order to signal the armature (12) to fall to the moved-out position.

12. An electronic control device (24) for operating a solenoid valve (10) for an electropneumatic drive device for use in a process production plant according to one of the preceding claims, characterized in that the solenoid valve (10) is switchable between an open-on state and a closed-on state; the electronic control device includes:

a supply output for applying an excitation current to a coil (18) of the solenoid valve (10) in order to switch the solenoid valve (10) from the closed-switch state to the open-switch state;

switching regulator for regulating the excitation current at the coil (18), wherein the switching regulator is designed to apply a pull-in current to the coil (18) of the solenoid valve (10) when switching into the open-switch state and to apply a holding current to the coil (18) for subsequently maintaining the open-switch state, which holding current is smaller than the pull-in current.

13. Electronic control device (24) according to claim 12, characterised in that it has a sensor for detecting whether the solenoid valve (10) has reached a specific switching state, wherein the sensor is supplied by an input voltage applied to the electronic control device (24) and/or the sensor is arranged in a recess of the metal body of the magnetic ground (14)

The electronic control device comprises a circuit board for the power electronics of the switching regulator, wherein a magnetic sensor located on the circuit board is arranged in a recess of the metal body of the magnetic ground (14).

14. The electronic control device (24) according to claim 13, wherein the specific switch state is an on-switch state.

15. An electronic control device (24) as claimed in claim 13, characterized in that the recess is a slot (20).

16. Electronic control device (24) according to claim 12 or 13, characterised in that said switching regulator has: a resistance (26) in series with the coil (18) configured to produce a rising voltage drop substantially corresponding to the current applied to the coil (18); a comparator (28), the comparator (28) monitoring a voltage drop across the resistor (26) relative to a threshold value; a transistor (32) that interrupts current flow to the coil (18) when the threshold is reached; and a freewheeling diode (30) connected in parallel with the coil to dissipate current in the coil (18) when the comparator (28) interrupts current flow;

wherein the transistor (32) is switched on autonomously after a defined time in the range of at least 1 microsecond, so that the current flow from the coil (18) to earth again increases, wherein the threshold value is again interrupted by the comparator (28) when it is reached;

wherein the threshold value is adjustable in the comparator (28) to a lower threshold value for adjusting from pull-in current to holding current, so that the excitation current in the coil (18) can be adjusted to a desired holding current.

17. Electronic control device (24) according to claim 16, characterised in that said resistance (26) is a shunt resistance.

18. The electronic control device (24) of claim 16, wherein said transistor (32) is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET).