Control circuit for solenoid valve and method for monitoring switching state of solenoid valve

Abstract

The invention relates to a control circuit (20) for a solenoid valve (10), the solenoid valve having a magnetic coil (12) and a movable element (14) coupled to a valve element (16), the magnetic coil conveying the movable element in one direction when it is excited so as to move the valve element from its initial position to its activated position, the control circuit having a power supply (22) for optionally supplying current to the magnetic coil (12) of the solenoid valve and a measuring device (24) for measuring the voltage level of the magnetic coil (12) and / or the current level through the magnetic coil (12). A control unit (16) is connected to the measuring device (24) and determines the switching state of the solenoid valve and, if necessary, the fault state of the current supply and / or the solenoid valve based on the intended current supply state of the power supply (22) and the current curve and / or voltage curve measured by the measuring device (24) according to the position of the valve element (16) of the solenoid valve.

Description

Technical Field

[0001] The invention relates to a control circuit for a solenoid valve, a gas combustion system having a solenoid gas valve and such a control circuit, a method for monitoring the switching state of a solenoid valve, and a method for operating a gas combustion system having a solenoid gas valve using such monitoring of the switching state of the gas valve. Background Art

[0002] A solenoid valve typically has a magnetic coil and a movable element coupled to a valve element, wherein the magnetic coil conveys the movable element in one direction when it is excited so as to move the valve element from its initial position to its activated position. Depending on the use of the solenoid valve, it is usually necessary to monitor the switching state of the solenoid valve. For this purpose, the solenoid valve is usually equipped with a sensor or connected to an external sensor, which determines the switching state of the solenoid valve, for example, by detecting the position of the valve element or the fluid flow through the solenoid valve. Summary of the invention

[0003] The object of the present invention is to provide an improved device for monitoring the switching state of a solenoid valve.

[0004] This object is achieved by the teaching of the present invention.

[0005] According to the invention, a control circuit for a solenoid valve is provided, the solenoid valve having a magnetic coil and a movable element coupled to a valve element, wherein the magnetic coil conveys the movable element in one direction when it is excited so as to move the valve element from its initial position to its activated position, the control circuit having a power supply for optionally supplying current to the magnetic coil of the solenoid valve, a measuring device for measuring the voltage level of the magnetic coil and / or the current level through the magnetic coil, and a control unit connected to the measuring device, wherein the control unit is configured to determine the switching state of the solenoid valve based on the intentional current supply state of the power supply and the current curve and / or voltage curve measured by the measuring device according to the position of the valve element of the solenoid valve. The control unit is configured to infer the movement of the movable element of the solenoid valve when a signal peak is detected by the measuring device. The control unit is configured to determine the fault state of the current supply and / or the solenoid valve based on the intentional current supply state of the power supply and the signal peak of the measured current curve and / or voltage curve.

[0006] That is, according to the invention, no additional sensors or other additional components are required to monitor the switching state of the solenoid valve, but the monitoring is carried out by the control circuit that is already present with the measuring device that is usually already integrated. As a result, the solenoid valve and its control circuit can be manufactured more simply and cost-effectively, and the monitoring of the switching state of the solenoid valve can be carried out more effectively and simply.

[0007] The solution is based on the inventors' knowledge that, on the one hand, the magnetic coil of the solenoid valve generates an electromotive force (EMK) when it is excited by a current supply, by which the movable element and thus the valve element connected to the movable element are moved, and on the other hand, when the movable element is moved by an electromotive return force (anti-EMK), it is subjected to current induction. Therefore, by measuring the voltage level of the magnetic coil and / or the current level through the magnetic coil, the current induction can be detected and based on this, the movement of the movable element and, as a result, the switching state of the magnetic valve can be inferred.

[0008] In this regard, the initial position of the valve element can be closed or open depending on the application of the solenoid valve. Correspondingly, the activation position of the valve element can be open or closed depending on the application of the solenoid valve. The present invention is not limited to any particular structure of the solenoid valve and its components.

[0009] In this context, the power source is, for example, an internal current generator or battery of the control circuit or a current connection of the control circuit for connection to an external current generator or battery or circuit. The current supply state of the power source is therefore, depending on the embodiment of the power source, for example, a switched / opened or switched / off power source or an opened or blocked connection of the power source to the magnetic coil.

[0010] In one embodiment of the present invention, the control circuit further comprises an output device and the control unit is configured to determine the fault state of the current supply and / or the solenoid valve based on the determined switching state of the solenoid valve and transmit a signal to the output device for outputting a fault report according to the determined fault state. The output device for outputting the fault report can be, for example, a display and / or a speaker on the solenoid valve or on a device connected to the solenoid valve, or a computer device (e.g., a user's smartphone, a central control unit, etc.).

[0011] The control unit of the control circuit is preferably configured to infer a movement of the movable element of the solenoid valve when a signal peak (i.e. a peak in the voltage curve or the current curve) is detected by the measuring device. In this way, the control unit can, for example, infer an unintentional failure of the current supply when the measuring device detects a signal peak during an intentionally continued current supply to the magnetic coil, or infer an unintentional movement of the valve element into its initial position when the measuring device detects no signal peak after switching off the current supply to the magnetic coil.

[0012] In one embodiment of the invention, the measuring device can be connected to the control unit via a signal amplifier. In this way, the evaluation of the measurement signal can be improved by the control unit.

[0013] In one embodiment of the present invention, the control circuit may also include a control unit for controlling the power supply, the connection between the power supply and the magnetic coil of the solenoid valve and / or the safety device of the control circuit. The control unit of the control circuit is preferably connected to or integrated into such a control unit.

[0014] The above control circuit of the present invention can be applied in a gas combustion system in an advantageous manner. Therefore, the subject of the present invention is also a gas combustion system, which has: a gas burner, which can be supplied with combustible gas via a gas input pipeline and has an ignition element for generating a gas flame; an electromagnetic gas valve for selectively opening or blocking the gas flow through the gas input pipeline to the gas burner; and the above control circuit of the present invention for operating the electromagnetic gas valve.

[0015] In one design of the present invention, the control circuit may have a thermocouple (or a thermistor) positioned close to the gas burner as a power source, the thermocouple generating electrical energy from heat through the thermoelectric effect.

[0016] According to the present invention, a method for monitoring the switching state of a solenoid valve is also provided, wherein the solenoid valve has a magnetic coil to which current can be optionally supplied by a power supply and a movable element coupled to a valve element, wherein the magnetic coil conveys the movable element in one direction when it is energized so as to move the valve element from its initial position to its activated position, wherein the method has the following steps: measuring the voltage level of the magnetic coil and / or the current level passing through the magnetic coil; and determining the switching state of the solenoid valve according to the position of the valve element of the solenoid valve based on the intentional current supply state of the power supply and the measured current curve and / or voltage curve.

[0017] With this method the same advantages as those of the above-described control circuit of the invention can be achieved. With regard to advantages, basic insights and term definitions, reference is supplementarily made to the above explanations in conjunction with the control circuit of the invention.

[0018] In one embodiment of the invention, the method further comprises: determining a fault state of the power supply and / or of the solenoid valve based on the determined switching state of the solenoid valve, and transmitting a signal to an output device for outputting a fault message according to the determined fault state.

[0019] Preferably, a movement of the movable element of the solenoid valve is inferred when a signal peak in the measured current curve and / or voltage curve is detected (that is to say a peak in the voltage curve or the current curve). In this way, for example, an unintentional failure of the current supply can be inferred when a signal peak is detected during an intentionally continued current supply to the magnetic coil, or an unintentional movement of the valve element into its initial position can be inferred when no signal peak is detected after the current supply to the magnetic coil is switched off.

[0020] The method according to the invention can also be advantageously applied to a gas combustion system. Therefore, the subject of the invention is also a method for operating a gas combustion system, the gas combustion system having: a gas burner, the gas burner can be supplied with combustible gas via a gas supply line and having an ignition element for generating a gas flame; and a solenoid gas valve for selectively opening or blocking the gas flow through the gas supply line to the gas burner, wherein the switching state of the solenoid gas valve is monitored by the above-described method of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other features and advantages of the present invention are better understood from the following description of preferred, non-limiting embodiments with reference to the accompanying drawings, most of which are schematically shown:

[0022] Figure 1 The basic structure of the control circuit for the solenoid valve according to the present invention is shown;

[0023] Figure 2 A flow chart showing a method for monitoring a switching state of a solenoid valve according to an embodiment of the present invention; and

[0024] Figure 3 The structure of a gas combustion system having a control circuit for a gas valve according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0025] Figure 1 The basic concept of the present invention is shown by way of example.

[0026] The solenoid valve 10 includes a magnetic coil 12, a movable element 14 and a valve element 16. The valve element 16 can move between an initial position and an activation position to selectively open or close a fluid flow. The valve element 16 is connected to the movable element 14 so that the movement of the movable element 14 causes the movement of the valve element 16. The movable element 14 is, for example, a metal element or a magnetic element so that it is moved directly or indirectly (for example, via a fixed iron core) by an electromotive force (EMK) generated by the magnetic coil 12 that is supplied with current and is thus excited. The movable element 14 is preferably preloaded into its initial position so that the valve element 16 is also preloaded into its initial position.

[0027] The current supply to the magnetic coil 12 is realized by the control circuit 20. The control circuit 20 includes a power source 22, which is connected to the magnetic coil 12 of the solenoid valve 12 via a connecting line 23. If the power source 22 is, for example, a current generator, the power source can be selectively turned on and off so as to selectively supply current to the magnetic coil 12. If the power source 22 is, for example, a battery or a current connection terminal connected to an external power source, the connection to the magnetic coil 12 via the connecting line 23 can be selectively opened or blocked so as to selectively supply current to the magnetic coil 12.

[0028] The control circuit 20 further comprises a measuring device 24, which is coupled to the connecting line 23 and is designed to measure the voltage level of the magnetic coil 12 and / or the current level through the magnetic coil. The measuring signal of the measuring device 24 is preferably transmitted to a control unit 26 via a signal amplifier 25. The control unit 26 is configured to evaluate the (amplified) measuring signal of the measuring device 24 and to monitor the switching state of the solenoid valve 10 based thereon. The monitored switching state of the solenoid valve 10 corresponds to the position of its valve element 16. Based on the switching state of the solenoid valve 10 determined in this way, the control unit can therefore also determine a fault-free or faulty state of the current supply and / or the solenoid valve.

[0029] The control unit 26 is preferably connected to an output device 28, which is designed, for example, as a display and / or a loudspeaker or a smartphone. If the control unit determines a fault state of the power supply and / or the solenoid valve, the control unit sends a signal to the output device 28, which then outputs a fault message corresponding to the determined fault state.

[0030] As in Figure 1 As shown in , the control circuit 20 may further include a control unit 30. The control unit 26 is preferably connected to the control unit 30 or integrated into the control unit 30. Depending on the specific implementation of the current supply, the control unit 30 may, for example, control the power supply 22 or control the connection of the power supply 22 to the magnetic coil 12. In addition, the control unit 30 may provide safety measures for the operation of the control circuit 20 and / or the solenoid valve 10 when necessary.

[0031] The switching state of the solenoid valve 10 is monitored by the control circuit 20 which is present anyway with the aid of the measuring device 24 which is usually present therein. Figure 2 Elaborate on how monitoring works.

[0032] In the monitoring method 60, the voltage level of the magnetic coil 12 or the current level through the magnetic coil 12 is continuously measured by the measuring device 24 (step 602). In step 604, the magnetic coil 12 is supplied with current by the power supply 22, for example by activating a current generator. By supplying the magnetic coil 12 with current, the magnetic coil is excited and causes the movement of the movable element 14 by electromotive force, so that the valve element 16 moves into its activated position. When the current is continuously supplied, the magnetic coil 12 remains excited and holds the movable element 14 in its position, in which the valve element 16 is in its activated position.

[0033] In step 606, it is tested whether, during the intentional continuous current supply, a signal peak in the voltage level or current level is detected by the measuring device 24. When the current supply fails and thus the excitation of the magnetic coil 12 ends and the movable element 14 is thus moved back into its initial position by the preload, such a voltage peak is generated, which is induced in the magnetic coil 12 by the electromotive return force.

[0034] If a signal peak in the voltage or current profile is detected by control unit 26 in step 606, a fault state of the power supply (unintentional failure of the power supply) is determined in step 608. Then, in step 610, control unit 26 generates a corresponding fault message, which is output by output device 28.

[0035] If, however, no signal peak is detected in the voltage or current profile in step 606, no fault is determined in step 612. The solenoid valve 10 remains in its correctly activated switching state when current is continuously supplied to the solenoid coil 12. The test continues continuously to determine whether a signal peak is detected.

[0036] At a later moment, in step 614, the current supply to the magnetic coil 12 via the power supply 22 is terminated, for example by deactivating the current generator. Since the magnetic coil 12 is no longer supplied with current, the magnetic coil no longer generates an electromotive force, so that it no longer forces the movable element 14 and the valve element 16 into their activated positions.

[0037] In step 616, it is tested whether a signal peak in the voltage level or current level is detected by the measuring device 24 when the current supply is terminated. Such a voltage peak occurs when the movable element 14 moves back into its initial position and induces a current through the magnetic coil 12 by the electromotive return force.

[0038] If no signal peak in the voltage curve or current curve is detected by the control unit 26 in step 616, a fault state of the solenoid valve 10 (valve element 16 remains in the activated position) is determined in step 618. Then, in step 610, the control unit 26 generates a corresponding fault message, which is output by the output device 28. If, on the other hand, a signal peak in the voltage curve or current curve is detected in step 606, then it is determined in step 620 that there is no fault.

[0039] Now refer to Figure 3 The specific application of the control circuit 20 and the monitoring method in a gas combustion system is described in detail by way of example.

[0040] The gas burning system 40 has a gas burner 42 which is supplied with gas from a gas supply line 55 via a gas valve 10. The gas burner 42 includes an ignition element 46 for generating a gas flame and is provided with or connected to an operating element 48 for selectively opening and closing the ignition element 46.

[0041] The gas valve 10 is designed as a solenoid valve and is Figure 1 Similarly, it includes a magnetic coil 12, a movable element 14 and a valve element 16. Figure 3 1 and 2 , the preload spring 18 is also shown, which preloads the movable element 14 into its initial position. In the application described, the valve element 16 blocks the passage 17 of the gas supply line 44 through the gas valve in its initial position. When the magnetic coil 12 is supplied with current, the magnetic coil is excited and moves the movable element 14 to its activated position against the force of the preload spring 18, so that the valve element 16 also moves to its activated position, in which the valve element opens the passage 17 of the gas supply line 44. When the magnetic coil 12 is continuously supplied with current, the magnetic coil holds the movable element 14 and thus also holds the valve element 16 in its activated position against the force of the preload spring 18.

[0042] The control circuit 20 basically corresponds to Figure 1 The control circuit shown in Figure 3 In the embodiment of the present invention, the control circuit 20 has a thermocouple as a power source 22, which is arranged near the gas burner 42. The thermocouple 22 generates electrical energy due to the thermoelectric effect when heat is generated in the gas burner 42, thereby supplying current to the magnetic coil 12 of the gas valve 10. The control unit 26 is also connected to the operating element 48 of the gas burner 42, so that the control unit knows whether the user has started or ended the operation of the gas burner 42 when monitoring the switching state of the gas valve 10.

[0043] In addition, the control circuit 20 has a current blocking device 50, which can be activated by the control unit 30 as a safety measure when necessary (for example due to a fault in the gas burner 42) in order to block the current supply to the magnetic coil 12, thereby returning the gas valve 10 to its original position blocking the gas supply line 44.

[0044] The gas combustion system works as follows.

[0045] When the user wishes to use the gas burner 42, he activates the ignition element 46 by operating the operating element 48. This generates a flame in / on the gas burner 42, thereby generating heat, which also heats the thermocouple 22, so that the thermocouple 22 generates electrical energy. In this way, the current supply to the magnetic coil 12 of the gas valve 10 is started. By exciting the magnetic coil 12, the movable element 14 moves toward its activation position against the force of the preload spring 18. As a result, the valve element 16 also moves into its activation position and opens the passage 17 of the gas supply line 44 through the gas valve 10, thereby delivering gas to the gas burner 42. As a result, a gas flame is generated in / on the gas burner 42, which also heats the gas burner 42 more strongly and therefore also heats the thermocouple 22 more strongly. The current supply to the magnetic coil 12 is enhanced by the stronger current generation of the thermocouple 22 caused by this, so that the movable element 14 and thus the valve element 16 remain in its activation position. The measuring device 24 then detects a substantially constant voltage level or current level.

[0046] If, however, the ignition element 46 no longer generates a flame even though the user has not switched off the gas burner 42, the temperature in / at the gas burner 42 drops and therefore the current supply from the thermocouple 22 to the magnetic coil 12 also drops. As a result, the magnetic coil 12 no longer holds the movable element 14 in its activated position, so that the movable element 14 is moved back into its initial position by the preload spring 18 and therefore the valve element 16 is also moved into its initial position and closes the passage 17 of the gas supply line 44. Due to the movement of the movable element 14, an induced current is generated in the currentless magnetic coil 12 for a short period of time, so that the measuring device 24 detects a peak in the voltage level or current level. Due to the peak during the intended operation of the gas burner 42, the control unit 26 recognizes a faulty state of the current supply and causes the output device 28 to output a corresponding fault message to the user in order to inform the user that the operation of the gas burner has ended, even though he did not want to do so.

[0047] When the user wishes to terminate the operation of the gas burner 42, he switches off the ignition element 46 via the operating element 48. As a result, the flame in / on the gas burner 42 goes out and the temperature drops, so that the current supply to the magnetic coil 12 via the thermocouple 22 is also reduced. As a result, the magnetic coil 12 no longer holds the movable element 14 in its activated position, so that the movable element is moved back into its initial position by the preload spring 18 and the valve element 16 is therefore also moved into its initial position and closes the passage 17 of the gas supply line 44. Due to the movement of the movable element 14, an induced current is generated in the currentless magnetic coil 12 for a short period of time, so that the measuring device 24 detects a peak in the voltage level or the current level.

[0048] However, if the movable element 14 does not move but remains in its activated position, and therefore the valve element 16 also allows the passage 17 of the gas supply line 44 to be opened, no induced current is generated in the magnetic coil 12. Accordingly, no peak in the voltage level or current level is detected by the measuring device 24. Due to the lack of peaks after the intentional operation of the gas burner 42 has ended, the control unit 26 recognizes the fault state of the gas valve and the output device 28 outputs a corresponding fault message to the user in order to inform the user of the faulty gas valve 10.

[0049] Reference numerals list

[0050] 10 Solenoid valve

[0051] 12 Magnetic coil

[0052] 14 Moving parts

[0053] 16 Valve element

[0054] 17 access

[0055] 18 Preload spring

[0056] 20 Control Circuit

[0057] 22 Power Supply

[0058] 23 Connection lines

[0059] 24 Measuring device

[0060] 25 Signal Amplifier

[0061] 26 Control Unit

[0062] 28 Output device

[0063] 30 Control unit

[0064] 40 Gas combustion system

[0065] 42 Gas Burner

[0066] 44 Gas input pipeline

[0067] 46 Ignition element

[0068] 48 Operating elements

[0069] 50 Current interrupting device

[0070] 60 Methods

[0071] 602 Measuring voltage level or current level

[0072] 604 Start current supply

[0073] 606 Test whether the signal peak is detected

[0074] 608 Determine the fault status of the current supply

[0075] 610 Generate fault report

[0076] 612 Confirmed no fault

[0077] 614 End current supply

[0078] 616 Test whether the signal peak is detected

[0079] 618 Determine the fault status of the solenoid valve

[0080] 620 Confirmed no fault

Claims

1. A control circuit (20) for a solenoid valve (10), the solenoid valve having a magnetic coil (12) and a movable element (14) coupled to a valve element (16), wherein: The magnetic coil (12) conveys the movable element (14) in one direction when it is excited, in order to move the valve element (16) from its starting position into its activated position, wherein the control circuit (20) has: a power source (22) for supplying current to the magnetic coil (12) of the solenoid valve (10); a measuring device (24) for measuring the voltage level of the magnetic coil (12) and / or the current level through the magnetic coil (12); and a control unit (26) connected to the measuring device (24), wherein the control unit (26) is configured to determine the switching state of the solenoid valve (10) based on the intended current supply state of the power supply (22) and the current curve and / or voltage curve measured by the measuring device (24) as a function of the position of the valve element (16) of the solenoid valve, The control unit (26) is configured to infer a movement of a movable element (14) of the solenoid valve (10) when a signal peak is detected by the measuring device (24). The control unit (26) is configured to determine a fault state of the power supply and / or the solenoid valve (10) based on an intentional power supply state of the power source (22) and a signal peak value of a measured current curve and / or voltage curve.

2. The control circuit according to claim 1, wherein: The control circuit (20) also has an output device (28); and The control unit (26) is configured to transmit a signal to the output device (28) for outputting a fault message as a function of the determined fault state.

3. The control circuit according to claim 1, wherein: The control unit (26) is configured to: When a signal peak is detected during the intentional continued supply of current to the magnetic coil (12), an unintentional failure of the current supply is inferred, and If no signal peak is detected after the current supply to the solenoid (12) is switched off, a failure movement of the valve element into its initial position is inferred.

4. The control circuit according to any one of claims 1 to 3, wherein: The measuring device (24) is connected to a control unit (26) via a signal amplifier (25).

5. The control circuit according to any one of claims 1 to 3, wherein: The control circuit also has a further control unit for controlling the power supply (22), the connection of the power supply to the magnetic coil (12) of the solenoid valve and / or the safety device (50) of the control circuit (20).

6. A gas combustion system (40) comprising: a gas burner (42) which can be supplied with combustible gas via a gas supply line (44) and has an ignition element (46) for generating a gas flame; a solenoid valve (10) for opening or blocking the inflow of gas through the gas input pipeline (44) to the gas burner (42); and A control circuit (20) for controlling the solenoid valve (10), wherein: The control circuit (20) is a control circuit according to any one of claims 1 to 5.

7. The gas combustion system according to claim 6, wherein: The control circuit (20) has a thermocouple as a power source (22) located close to the gas burner (42), the thermocouple generating electrical energy from heat through the thermoelectric effect.

8. A method for monitoring a switching state of a solenoid valve (10), the solenoid valve having a magnetic coil (12) which can be supplied with current by a power supply (22) and a movable element (14) coupled to a valve element (16), wherein: The magnetic coil (12) conveys the movable element (14) in one direction when it is excited in order to move the valve element (16) from its starting position into its activated position, wherein the method comprises: measuring a voltage level of the magnetic coil (12) and / or a current level through the magnetic coil (12); determining a switching state of the solenoid valve (10) based on an intended current supply state of the power source (22) and a measured current curve and / or voltage curve as a function of a position of a valve element (16) of the solenoid valve; Upon detecting a signal peak in the measured current curve and / or voltage curve, inferring a movement of a movable element (14) of the solenoid valve (10); and A fault state of the power supply and / or of the solenoid valve (10) is determined based on an intentional power supply state of the power source (22) and a signal peak value of the measured current curve and / or voltage curve.

9. The method according to claim 8, wherein: The method also has: A signal is transmitted to an output device (28) for outputting a fault message according to the determined fault state.

10. The method according to claim 8, wherein: If a signal peak is detected during the intentional continued supply of current to the magnetic coil (12), an unintentional failure of the current supply is inferred.

11. The method according to claim 8 or 9, wherein: If no signal peak is detected after the current supply to the solenoid (12) is switched off, a failure movement of the valve element (16) into its initial position is inferred.

12. A method for operating a gas combustion system (40), the gas combustion system comprising: a gas burner (42) which can be supplied with combustible gas via a gas supply line (44) and has an ignition element (46) for generating a gas flame; and a solenoid valve (10) for opening or blocking the inflow of gas through the gas supply line (44) to the gas burner (42); wherein: The switching state of a solenoid valve (10) is monitored by a method according to any one of claims 8 to 11.

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