Electric air filter device and method for operating the same

Abstract

An electrostatic air filter device (1) and a method for operating the electrostatic air filter device (1) are proposed. The electrostatic air filter device (1) is designed to filter air flowing through it and comprises an ionizer (2) for ionizing air particles (3) in an electrostatic field generated by applying an electrical voltage supplied by a controllable electrical power source (21) to the ionizer (2). The electrostatic air filter device (1) further comprises an electrical control circuit (20) for controlling the controllable electrical power source (21). The electrical control circuit is configured to detect at least one current power parameter of the ionizer (2) to determine its current state and to adjust the electrical power source at least partially based on the detected power parameter.

Description

Field of invention

[0001] The present disclosure relates generally to a filter device. In particular, the present disclosure relates to an electrostatic air filter device and a method for operating the electrostatic air filter device. Background and general description of the invention

[0002] Filter devices such as electrostatic air filters are known, comprising an ionization device or ionizer for ionizing airborne particles and a collection device or collector for capturing the ionized airborne particles. These filters typically employ strong electrostatic fields or high voltages to ionize airborne particles. This can lead to electrical arcing or spark gaps, malfunctions, reduced separation efficiency, and ultimately, destruction of the electrostatic air filter, particularly if the ionizer becomes contaminated.

[0003] While arcing can generally be avoided by reducing the applied voltage, this can lead to a reduction in the ionization efficiency of the ionizer and consequently to a decrease in the filtration efficiency of the electrostatic air filter device.

[0004] German patent application DE 10 2022 103 550 A1 discloses a control circuit for an electrostatic precipitator. The control circuit is designed to generate a high voltage from a low voltage DC source. It includes a control loop configured to regulate the output power, for example, to prevent spark discharges of the DC plasma.

[0005] US patent 2020 / 0188931 A1 discloses an electrostatic device with a corona field electrode for generating an electrostatic field. The primary low voltage applied to the corona field electrode is measured in the ground loop to detect wear of the corona field electrode. The setup shown in the patent application is a primitive, single-stage design in which all dirt is collected directly in the area of ​​the corona field electrode. Furthermore, it follows that the simplicity of the design makes measurement in the ground loop of the low-voltage section possible at all, since no other components influence the total currents flowing to ground. A further disadvantage of this design is its extremely rapid wear, making it rather unsuitable for long-life industrial filters or continuous operation.

[0006] WO 2006 / 000114 A1 discloses a control unit for regulating the operating voltage and monitoring wear in a device for electrostatic particle filters. A corona rod electrode is mounted lengthwise along the center of a flue gas pipe and subjected to high voltage, creating an electrostatic field around the electrode and causing it to oscillate. To prevent excessive oscillations while ensuring optimal filtration, the control unit measures the frequency and amplitude of the alternating current component generated by the electrode's oscillation. The oscillation is also monitored to detect fouling of the oscillating electrode.

[0007] One objective of the embodiments of the present disclosure is to provide an electrostatic air filter device and a method for operating the electrostatic air filter device, which enable efficient and reliable air filtration.

[0008] In one aspect, the task of the embodiments of the present disclosure focuses on improving existing electrostatic air filter devices, in particular with a focus on maintaining a uniform filter performance even during continuous operation.

[0009] To solve this task, an electrostatic air filter device is provided for filtering air flowing through the electrostatic air filter device, according to a first aspect.

[0010] The electrostatic air filter device comprises an ionizer for ionizing airborne particles in an electrostatic field generated by applying an electrical voltage supplied by a controllable electrical power source to the ionizer. In particular, the ionizer can be essentially configured as a flow channel with a number of first electrodes (cathodes) and a number of second electrodes (anodes). By applying the electrical voltage to the electrodes, a potential difference can be generated between the first and second electrodes. This electrostatic field, used to ionize the airborne particles or dirt particles, can then be generated between the first and second electrodes.

[0011] In some embodiments, the first electrodes comprise a number of wire-shaped electrodes or electrically conductive wires oriented substantially transversely to an airflow direction, while the second electrodes typically comprise a number of planar electrodes or plates spaced apart from the wires and essentially parallel to the plane. Various types of tips can also be used instead of wires as electrodes.

[0012] In other words, according to the present application, the ionizer is a first filter component with a first or a plurality of first and a second or a plurality of second electrodes, which provides a first electrostatic field for the airflow through it.

[0013] The electrostatic air filter device can include a collector downstream of the ionizer for capturing the air particles ionized in the ionizer. The collector can also include, in particular, a number of electrodes for generating an electrostatic field directed substantially transversely or obliquely to the main airflow direction. The ionized or charged air particles can be deflected by the electrostatic field of the collector, thus removing such particles from the airflow.

[0014] In other words, the collector is a second filter component positioned downstream of the ionizer, comprising a third or multiple third and a fourth or multiple fourth electrodes, thus providing a second electrostatic field for the passing airflow. The third and fourth electrodes are typically plate-shaped. The particles passing through the collector have been ionized in the ionizer and are therefore easily deflected by the electrostatic field. Since the collector electrodes have a significantly larger surface area than the ionizer electrodes, considerably more particles can be captured and thus separated. This two-part design, with the ionizer on one side and the downstream collector on the other, allows the ionizer to remain free of dirt for longer periods.Furthermore, it can be significantly easier to clean or empty the collector.

[0015] The electrostatic air filter device further comprises an electrical control circuit for controlling the adjustable electrical power source, wherein the electrical control circuit is configured to detect or monitor at least one current performance parameter of the ionizer in order to determine a current state of the ionizer. The state can be, for example, the degree of contamination in the ionizer.

[0016] In this context, a power parameter is understood to be a parameter relevant to and / or reflecting electrical power. In particular, electrical current, electrical voltage, and / or a product thereof, i.e., electrical power, can be used as a power parameter.

[0017] The electrical control circuit is further configured to adjust the electrical power source at least partially based on the detected at least one current power parameter, so that the electrostatic field of the ionizer can be adjusted taking into account the current pollution level of the ionizer.

[0018] In particular, the electrical control circuit can be configured to detect a change in at least one performance parameter due to contamination, in order to control the power source to compensate for a change in the ionization power of the ionizer. By adjusting the electrical power source, it can be ensured that the electrostatic air filter device for stabilizing the ionization power is always operated according to the current degree of contamination of the ionizer. In other words, the power applied to the ionizer can be adapted or readjusted to the degree and / or type of contamination.

[0019] In other words, it can be described as follows. The ionizer contains an ionization volume within which the ionizer provides an electric field strength sufficient to ionize particles passing through the ionization volume. The electric field is preferably set such that it ionizes the particles passing through, but does not capture or deposit the particles within the ionizer.

[0020] The electrical control circuit is configured to regulate the ionization volume provided in the ionizer and / or collector in response to changes in the state, in particular to adjust it such that the ionization efficiency (or capture efficiency in the case of the collector) provided for particles flying into or through the ionizer and / or collector remains constant over time. The ionization volume is typically regulated by changing the applied voltage, and possibly also the current. The ionization volume can also be regulated by changing the plate separation x or y (see [reference]). Fig. 2 The regulation of the ionization volume therefore usually refers to a change in the provided electrostatic field properties, especially the field strength.

[0021] At least one current performance parameter of the ionizer and / or collector can include the current flowing through the ionizer and / or collector. In particular, the electrical control circuit can be designed to detect the current flowing through the ionizer and / or collector. Especially with a given output voltage of the power source or a voltage applied to the ionizer and / or collector, the current flowing through the ionizer and / or collector allows conclusions to be drawn about the current state of contamination of the ionizer and / or collector. For example, if the current flow between the first and second electrodes of the ionizer, or between the third and fourth electrodes of the collector, decreases, this can serve as an indicator of contamination of the ionizer and / or collector by electrically non-conductive or insulating dirt particles.If, on the other hand, the current flow between the first electrodes (wires) and second electrodes (plates) of the ionizer increases, or between the third and fourth electrodes of the collector, especially at a constant voltage, this can indicate contamination of the ionizer and / or the collector with electrically conductive particles.

[0022] The electrical control circuit can be configured to reduce the output voltage of the electrical power source when an increase in at least one performance parameter is detected, indicating contamination of the ionizer and / or collector with electrically conductive particles. In particular, the output voltage of the electrical power source or the voltage applied to the ionizer and / or collector can be reduced if, for example, an increasing current flow is detected. The detection of the power or current increase can be specifically identified and, if necessary, corrected by a corresponding reduction in voltage before a flashover occurs, thereby preventing flashovers in the ionizer and / or collector.

[0023] The electrical control circuit can be configured to reduce the output voltage of the electrical power source while maintaining essentially the same electrical power. Specifically, the voltage applied to the ionizer and / or collector can be adjusted to reduce the risk of flashovers without reducing the ionization power of the ionizer and / or the capture power of the collector. This is because the power would measurably increase if the ionizer and / or collector became contaminated with electrically conductive particles, which can then be corrected by lowering the voltage.

[0024] The electrical control circuit can be configured to increase the output voltage of the electrical power source when a drop in at least one performance parameter is detected, indicating contamination of the ionizer and / or collector with electrically non-conductive particles. In particular, the ionizer current can be increased to a preset and / or desired setpoint. This allows, in particular, the compensation of a performance drop attributable to contamination of the ionizer and / or collector.

[0025] In some embodiments, the electrical power of the ionizer and / or the collector is used as a control parameter when adjusting the electrical power source. In particular, the electrical power source can be adjusted so that the electrical power of the ionizer and / or the collector remains essentially constant. This control is based on the understanding that the electrical power of the ionizer and / or the collector can be used as an indicator of the contamination of the ionizer or ionizer electrodes and / or the collector or the collector electrodes.

[0026] For example, if the plates of the ionizer and / or collector become contaminated with non-conductive particles, this can lead to a reduction in current flow and lower ionization power. Even if the wire potential or the voltage applied to the ionizer and / or collector remains constant, electrically insulating contamination of the plates, wires, or tips can significantly affect the electrostatic field within the ionizer and / or collector. For instance, an electric charge accumulated on the surface of an insulating layer of dirt, possibly due to polarization occurring there, can lead to a reduction in the electric field strength around or within the wires. In addition to the current, the ionization power also decreases, especially if the ionizer voltage remains constant.By monitoring and regulating the electrical power of the ionizer and / or the collector, the ionization power and, as a result, the overall filter performance can be kept or stabilized within an optimal range.

[0027] It is particularly preferred that both the electrical power of the ionizer and the electrical power of the collector can be monitored and controlled. It is further preferred to monitor both power parameters (current and voltage) of the ionizer and, optionally, separately from the ionizer, the power parameters (current and voltage) of the collector. This allows for appropriate responses to contamination of both the ionizer and the collector, particularly to prevent flashovers and optimize filter efficiency.

[0028] Finally, it is possible, and with optimal design of the filter components, even desirable, that the electrostatic collector field changes as the collector fills with particles long before the electrostatic excitation field of the ionizer changes. In this case, too, the control system can be adjusted accordingly, and the collector field can be increased.

[0029] The capture of conductive particles in the collector, a common occurrence in the metalworking industry, has also proven to be critical. In such cases, it has been observed that the ionizer itself is usually hardly affected and remains largely uncontaminated, while the conductivity of the collector electrodes increases significantly, thus promoting arcing within the collector. In this specific situation, the simultaneous measurement and control of both the ionizer and collector performance parameters has proven invaluable.

[0030] In some embodiments, the electrostatic air filter device includes an output or display device for outputting or displaying a current value of at least one performance parameter of the ionizer and / or the collector. Alternatively or cumulatively, the output or display device shows a signal, for example, by means of a yellow and / or red indicator light. In other words, the output or display device is preferably a status indicator. Based on the status indicator or the output value of the at least one performance parameter, the need for maintenance (or cleaning) of the electrostatic air filter device can be determined or indicated, in order to carry out appropriate maintenance work if necessary.

[0031] A second aspect describes a method for operating an electrostatic air filter device according to the first aspect. This method involves generating an electrostatic field in the ionizer by applying an electrical voltage, generated by a controllable electrical power source, to the ionizer or to ionizer electrodes.

[0032] The method further comprises acquiring at least one current performance parameter of the ionizer and / or the collector to determine its current state and adjusting the at least one electrical power source, at least partially, based on this current performance parameter, so that the electrostatic field of the ionizer and / or the collector can be adapted to the current state, in particular the degree of soiling, of the ionizer and / or the collector. Adjusting the electrical power source ensures, in particular, that the operation of the electrostatic air filter device is always optimally matched to the current degree of soiling of the ionizer and / or the collector.

[0033] Applying voltage to the ionizer and / or the collector can involve applying an initial voltage below a certain threshold. In particular, the initial voltage or threshold can be chosen close to a flashover threshold, specifically high enough to prevent flashovers between the electrodes or between the wires and the plates of the ionizer and / or collector. Such an initial voltage is particularly suitable when contamination with predominantly electrically conductive particles is expected.

[0034] In some embodiments, the voltage threshold is set below a flashover threshold with a safety margin. The voltage can then be increased if necessary. This allows the ionization power to be stabilized by increasing the voltage without reaching the flashover threshold. This operating mode is particularly preferred when contamination with electrically non-conductive particles is expected.

[0035] Applying voltage to the ionizer can involve setting an initial power level below a certain threshold. Specifically, the initial power (product of initial current and initial voltage) can be chosen to be lower than the maximum power of the electrical power source. This provides the power source with reserves, allowing for dynamic adjustments as needed, particularly in the event of deviations from the nominal power in either direction.

[0036] The invention is described in more detail below with reference to exemplary embodiments and the figures, wherein identical and similar elements are partially provided with the same reference numerals and the features of the different exemplary embodiments can be combined with one another. Brief description of the characters: It shows:

[0037] Fig. 1 schematic perspective view of an electric air filter device according to an embodiment in operation, Fig. 2 schematic electrical circuit for operating an electric air filter device according to an embodiment, and Fig. 3 a flowchart of a method for operating an electric air filter device according to an embodiment. Detailed description of the invention:

[0038] Fig. 1 Figure 1 shows a schematic perspective view of an electric air filter device according to an exemplary embodiment in operation. The electric air filter device 1 is designed to filter air flowing through it. The airflow through the electric air filter device 1 is... Fig. 1This is illustrated by means of broad arrows 7, 17. In the illustrated embodiment, the electrostatic air filter device 1 comprises an ionizer 2 for ionizing airborne particles 3 or dirt particles in the air, and a collector 4 downstream of the ionizer 2 for capturing the airborne particles 5 ionized in the ionizer. The electrostatic air filter device 1 further comprises a pre-filter 6 upstream of the ionizer 2 for pre-filtering air 7 flowing into the electrostatic air filter device 1, and a final filter 8 downstream of the collector 4 for post-filtering air 9 flowing out of the collector 4.

[0039] The ionizer 2 comprises a number of first electrodes 10 in the form of parallel, electrically conductive wires oriented transversely to the airflow, and a number of second electrodes 11 in the form of spaced-apart, electrically conductive plates with plate planes parallel to the airflow. The collector 4 comprises a number of first electrodes 12 and a number of second electrodes 13, wherein the electrodes 12, 13 of the collector 4 are configured as capacitor plates with a plate plane oriented parallel to the airflow.

[0040] During operation of the electric air filter device 1, an ionizer voltage or voltage between the first electrodes 10 and the second electrodes 11 as well as a collector voltage or voltage is applied.

[0041] A voltage is applied between the first electrodes 12 and the second electrodes 13 of the collector 4. The ionizer voltage and the collector voltage can, for example, be provided by at least one voltage or electrical power source, which can be designed as part of the electric air filter device 1.

[0042] The incoming air 7, or the air to be filtered, is pre-filtered by the pre-filter 6, so that the air 14 entering the ionizer 3 is already coarsely pre-filtered. In the electrostatic field of the ionizer 2, air particles 3 that were not captured by the pre-filter 6 can be ionized. The wire-shaped first electrodes 10 of the ionizer 3 provide a high field strength for the ionization of air particles 3, which, to a first approximation, is homogeneously distributed between the first and second electrodes 10, 11. The effective cross-section for the ionization of passing air particles 3 is thus, to a first approximation, homogeneously distributed over the air volume, or ionization volume, encompassed by the ionizer 3. At least some of the air particles 3 are sufficiently ionized in the ionizer 3 so that the particles 3 can be captured in the downstream collector 4. Air 15 ionized as it passes through the ionizer 2Air with an increased density of ionized particles 5 thus enters the collector 4 located downstream of the ionizer 2.

[0043] The (sufficiently) ionized particles 5 are deflected and deposited in the electrostatic field of the collector 4. The deflection of the ionized particles 5 in the collector 4 is measured in Fig. 1 symbolized by curved trajectories of the ionized particles 5. The deflected ionized particles 5 can be deposited as dirt, particularly at the electrodes 12, 13 of the collector 4. The dirt 16 deposited in the collector is Fig. 1 symbolically represented as drops falling from collector 4.

[0044] Depending on the application, the air 9 flowing out of the collector 4 can be subjected to further filtration, in particular fine filtration by the final filter 8. Specifically, the final filter 8 can be designed with a finer mesh than the pre-filter 4, for example, as a nanofilter. As a result, the air flowing into the electrostatic air filter device 1 is filtered three times: coarsely in the pre-filter 6, electrostatically in the ionizer and collector, and finely in the final filter 8, so that clean air 17, purified three times, flows out of the electrostatic air filter device 1.

[0045] The division of the electrostatic filter unit into ionizer 2 and collector 4 protects ionizer 2 from excessive wear and contamination, since particles 3 and 5 are not deposited in ionizer 2, but are merely ionized there sufficiently to be captured in collector 4. Thus, ionizer 2 can be optimized with regard to excitation without regard to the (subsequent) deposition of particles 3 and 5 in the collector. Thanks to the two-part design, ionizer 2 becomes significantly less contaminated. However, within the scope of this description, it has proven advantageous to capture the contamination of collector 4.

[0046] Fig. 2Figure 20 schematically shows an electrical circuit for operating an electric air filter device according to an exemplary embodiment, in which the ionizer 2 and the collector 4 are also schematically depicted for better clarity. The circuit 20 comprises an electrical power source 21, wherein the electrical power source 21 is connected in this example both to the ionizer for generating the electrostatic field of the ionizer 2 and to the collector 4 for generating the electrostatic field of the collector 4. In other words, the ionizer 2 and the collector 4 share a common power source 21, so that the power source 21 provides both the ionization field in the ionizer 2 and the collector field in the collector 4.

[0047] For example, collector 4 can be operated at half the potential of ionizer 2.

[0048] In one example, 12 kV can be applied to the ionizer 2 and 6 kV to the collector 4, where the applied voltage uA depends on the plate spacing y and / or the condition of the ionizer 2 - i.e. typically the degree of pollution or damage to the ionizer 2 and / or the collector.

[0049] Electrodes 10 and 11 of ionizer 2 and electrodes 12 and 13 of collector 4 are in Fig. 2 also shown schematically, whereby the person skilled in the art can see directly, or at least in conjunction with the, the shape of the plate capacitor as collector 4 as well as the wires 10 and terminal plates 11 shown. Fig. 1 ,The diagram, which shows a functional sketch, also reveals a possible design for each component. The wire-shaped electrodes are marked with a diamond, and the plate-shaped electrodes are shown as lines. To generate the electrostatic field of the ionizer 2, a high voltage is applied between electrodes 10 and 11 of the ionizer 2 by means of the electrical power source 21. To generate the electrostatic field of the collector 4, a high voltage is again applied to electrodes 12 and 13 of the collector 4 by means of the electrical power source 21.

[0050] The circuit could also include two separate power sources 21, with one power source 21 supplying the ionizer 2 and the other power source 21 supplying the collector 4 separately. An advantage of two separate power sources 21 is that if the collector 4—but not the ionizer 2—becomes dirty, only the collector field would need to be changed, whereas with a shared power source 21, both fields are usually changed together. However, the shared power source 21 used in this example reduces costs while maintaining essentially the same functionality in practice. This is because it has been shown that the limitation hardly reduces the filter performance significantly.

[0051] Circuit 20 further comprises an ammeter 23 for measuring the current flowing through ionizer 2, an ammeter 24 for measuring the current flowing through collector 4, a voltmeter 22 for measuring the voltage applied to ionizer 2, and a voltmeter 25 for measuring the voltage applied to collector 4. The current and voltage measurements at measuring points 22, 23, 24, and 25 are performed in the high-voltage path. Measuring in the high-voltage path allows for the most independent possible measurement of the respective parameters, so that the measurement results do not influence each other.

[0052] In the simplest case of the invention, it would in principle be possible to equip the circuit only with the voltage measuring device 22. Equipping the circuit with measuring devices 22 and 23 is preferred. However, monitoring all separate parameters via the measuring devices 22, 23, 24, and 25 provides even more extensive functionality, namely, in particular, the detection of contamination of both the collector 4 and the ionizer 2.

[0053] The electrical power source 21 can be configured, in particular, as a controllable or adjustable electrical power source. Specifically, the power source 21 can be configured as a voltage source for outputting an adjustable voltage, as a current source for applying an adjustable current, and / or as a power source for applying an adjustable electrical power. In particular, the electrical power source can be configured to be controlled by a control unit 27, in particular via a voltage regulator 26, that is, on the one hand, to regulate the voltage to be output by the voltage source 21, and on the other hand, to activate a safety function, such as switching off the voltage source 21, in the event of a sudden change of state. In particular, the control circuit 20 can include the control unit 27 for controlling the power source 21.The control unit 27 can, in particular, comprise a processor and a memory unit for storing data and machine-readable instructions for the processor, as well as an interface. The interface can be configured to receive and / or process current measured values ​​from the ammeters 23, 24 and / or the voltmeters 22, 25. The interface can also be configured to output control signals for controlling the electrical power source 21, in particular to or by means of the voltage regulator 26, which can also be integrated internally into the control unit 27. The interface of the control unit 27 can also be configured to be connected to a user interface 29, e.g., via a touchscreen or keyboard, for receiving user input or commands.Furthermore, it is particularly relevant if a display device 28, such as a warning lamp, a digital transmission or a filter status indicator, is provided for outputting information relevant to the operation of the electrostatic air filter device.

[0054] The control unit 27 can be configured, in particular by storing data and machine-readable instructions. Specifically, the control unit can be configured to receive current readings from current meters 23, 24 and / or voltage meters 22, 25, and to control the electrical power source 21, at least partially, based on the received current values. Specifically, the control unit 27 can be configured to evaluate received readings and determine the current pollution level of the ionizer 2 based on these readings. The control unit 27 can further be configured to control the electrical power source 21 such that the electric field of the ionizer 2 can be adjusted taking into account the current pollution level of the ionizer 2.

[0055] With Fig. 2Furthermore, another significant development made possible by the present description will be illustrated. Electrode spacings x, or distances between the first electrodes 12 and the second electrodes 13 of the collector 4, and electrode spacings y, or distances between the first electrodes 10 and the second electrodes 11 of the ionizer 2, are shown symbolically. This is intended to emphasize the important role of the electrode geometry and electrode spacing in shaping the electrostatic field in the collector 4 and the ionizer 2, respectively. The possible distances x, y of the electrodes 10, 11, 12, 13 depend primarily on the applied voltage. This development makes it possible to optimize, i.e., reduce, the electrode spacing 10 -> 11 (y) and / or the electrode spacing 12 -> 13 (x).For example, thanks to the adjustable voltage source 21, the voltage does not have to be set to a fixed "maximum value," but rather a voltage value can be output that does not correspond to the maximum possible output voltage of the source 21. Thus, the circuit 20 according to the invention makes it possible to maintain power reserves. Such power reserves can be accessed when a change of state occurs, particularly in the ionizer 2 and / or the collector 4, for example, a gradual increase in the soiling of the electrodes 10, 11, 12, 13 over the filter's operating time. The filter's service life can therefore be significantly increased, and the filtration efficiency can also be kept more constant over the filter's operating time.

[0056] If the voltage source 21 outputs a constant voltage to the downstream circuit and the ionizer 2 and / or the collector 4 gradually become contaminated with non-conductive particles, the output power will decrease. This can be detected by the ammeter 23 located in the current path of the ionizer 2 or the ammeter 25 located in the current path of the collector 4. Since a decrease in power indicates contamination by non-conductive particles, the controller 27 can safely increase the voltage output by the source 21 in response to the measured value from the ammeter 23, 25. Finally, electrodes 10, 11, 12, 13, especially the plate-shaped electrodes 13, can be covered with a non-conductive layer, so that even when the voltage is increased, no flashovers (sparks) between electrodes 10, 11 or 12, 13 are to be expected.When a corresponding threshold value (typically voltage or current) is reached or exceeded, information can be output via a display device 28, for example an operating lamp.

[0057] If, however, the power increases under the same initial conditions, which can also be measured via the current from the measuring device 23, 25, the control unit 27 can reduce the voltage supplied by the source 21 in response to the measured value, for example, with the aim of keeping the power supplied by the source 21 constant. A gradually increasing power consumption indicates contamination of the ionizer 2 and / or the collector 4 with conductive particles. If a corresponding threshold value is undershot, information can also be output via a display device 28, such as an operating lamp.

[0058] Furthermore, in addition to the degree of pollution, other status information can be obtained from circuit 20. For example, if a sudden and significant increase or decrease in the power consumed by ionizer 2 is measured, this may indicate a defect. This information can also be displayed via the display unit 28, and the power output from source 21 can also be stopped. Thus, circuit 20 can also perform a safety function.

[0059] Fig. 3 Figure 1 shows a flowchart of a method for operating an electrostatic air filter device according to an exemplary embodiment. The method 100 can be carried out in particular using the electrostatic air filter device 1 according to Figure 1. Fig. 1 or by means of circuit 20 of the Fig. 2The following steps are carried out according to method 100: In process step 110, an electrostatic field is generated in the ionizer 2. This can be done, in particular, by applying a voltage supplied by the adjustable electrical power source 21 to the ionizer or to its electrodes 10, 11.

[0060] Process step 110 can also include generating an electrostatic field in collector 4 in conjunction with step 115. In particular, the electrostatic fields in the ionizer 2 and in the collector 4 can be generated essentially simultaneously by means of a common electrical power source, cf. Fig. 2 above. However, it may also be possible to provide the collector field with a separate, dedicated power source.

[0061] In process step 120, at least one current performance parameter of the ionizer 2 and / or the collector 4 is recorded.

[0062] Method 100 further comprises readjustment 130 of the power source, at least partially, based on at least one current power parameter. In particular, readjustment of the power source allows the electrostatic ionizer field and / or the collector field generated in ionizer 2 to be adjusted or modified according to the current degree of pollution of ionizer 2 and / or collector 4.

[0063] In some embodiments, the method comprises 100 evaluations of at least one performance parameter, in particular by means of a control unit or a control and evaluation unit. The readjustment can be carried out automatically, in particular by means of a control loop, and / or by means of the control unit after the evaluation of the at least one performance parameter.

[0064] Applying voltage to the ionizer 2 in process step 110 and / or to the collector field in process step 115 can involve applying an initial voltage below a voltage threshold, particularly below a flashover threshold. The voltage threshold can be selected to provide a voltage reserve, allowing the voltage to be increased if necessary. Depending on the design, especially the electrode spacing, the initial voltage can be approximately 11 kV. This provides a voltage margin if the maximum voltage is limited to, for example, 13 kV due to the voltage limits of electromechanical components such as relays or insulators.

[0065] In some embodiments, applying the voltage to the ionizer 2 in process step 110 and / or the voltage to the collector 4 can include imprinting an initial power. In particular, the initial voltage can be applied under controlled power, so that the imprinted electrical power is set to a target value below a power threshold. The power threshold can be selected, in particular, to provide a power reserve to allow the power to be increased if necessary. Depending on the design, especially the electrode spacing and voltage, the initial power can be approximately 18 W, for example, with a current of 1,600 µA at 11 kV.

[0066] The following summarizes the key improvements achievable with this description. By recording and monitoring the performance parameters and adjusting the power source 21, the performance and reliability of the ionizer 2 and / or the collector 4, and consequently the entire electrostatic air filter device 1, can be improved. For example, if an increasing current flow through the ionizer 2, or between the first electrodes 10 and the second electrodes 11 of the ionizer 2 and / or the collector 4, and thus between electrodes 12 and 13, is detected, the voltage can be reduced accordingly. This reliably prevents voltage flashovers in the ionizer 2 and / or the collector 4 and significantly extends the service life and maintenance-free period of the electrostatic air filter device 1.If the current can be measured and thus regulated (by adjusting the voltage), a lower voltage can initially be selected at the wire (ionizer 2 and / or collector 4) during operation at the same power output, and the distance between the wire and the plate y can be reduced. This prevents arcing (sparking) and the resulting wire damage at the smaller distance y and lower voltage. The same applies to the plate spacing x of collector 4.

[0067] Using the method described here, the electrode spacing can also be optimized so that more or an optimized number of electrodes (wires and plates) can be accommodated in the same volume of the ionizer in order to further improve the filter performance.

[0068] Due to the power or voltage reserve, a power decrease caused by contamination can be compensated for, and the ionization performance stabilized. For example, if the plates 11 become contaminated with non-conductive particles, the current flow through the ionizer 2 decreases, even if the ionizer voltage or the wire potential with respect to the plates 11 remains constant, especially if the voltage is not readjusted. The current flow nevertheless decreases, and the ionization efficiency of airborne particles also decreases. The power therefore decreases because the current drops while the voltage remains constant. This can be measured, and the voltage can be readjusted so that increasing the voltage restores the desired current value. With regard to the collector 4, the capture efficiency decreases when it becomes filled with non-conductive particles 5.

[0069] In some embodiments, at least one performance parameter, in particular the electrical power of the ionizer 2 and / or the collector 4, is displayed as an indicator of maintenance requirements, so that the operator or user can initiate maintenance or cleaning work on the air filter device 1 as needed, based on the displayed parameter. In some embodiments, the ionizer voltage (at a constant current) and / or the collector voltage is used as an indicator of maintenance requirements. For example, if the ionizer voltage falls below a warning threshold of, say, 10 kV due to contamination with conductive particles, this can serve as a reason to clean the air filter device 1 to prevent degradation of the ionizer. Instead of a warning when the voltage falls below / exceeds a certain threshold, the warning, in particular the upper warning, can also be triggered only when the current falls below a certain threshold, e.g.,below 1000 µA. However, if the power should increase, for example if conductive particles have accumulated in the ionizer, this can be detected before arcing occurs. In such a case, the power would measurably increase, which can then be corrected by lowering the voltage.

[0070] As shown above, the electrical power source 21 can be controlled differently depending on the situation or state of contamination of the ionizer 2 and / or the collector 4. In particular, the ionizer current and / or power can be kept essentially constant by controlling the electrical power source. The electrical power source is therefore not a pure voltage source in the strict sense, but rather a "power source". In particular, the current flowing through the ionizer or between the electrodes of the ionizer is a better performance indicator of the ionizer than the voltage applied to it (the same applies to the collector).

[0071] In particular, in contrast to conventional electric air filter devices, in which the filter performance continuously decreases, the method proposed here thus enables monitoring and stabilization of the filter performance of the proposed air filter 1, so that the filter performance is kept in an optimal range.

[0072] The present description contains a large number of aspects which, individually or together with others, can define essential aspects of the invention(s).

[0073] It is evident to those skilled in the art that the embodiments described above are to be understood as examples and that the invention is not limited to this exemplary embodiment, but can be varied in many ways without departing from the scope of protection of the claims. Rather, the aforementioned embodiments are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. The preceding description provides those skilled in the art with a plan for implementing at least one exemplary embodiment, whereby numerous changes can be made to the function and arrangement of elements described in an exemplary embodiment without departing from the scope of protection of the appended claims and their legal equivalents. Furthermore, according to the principles described herein, several modules orSeveral products can be combined to obtain additional functions. Furthermore, it is evident that the features, regardless of whether they are disclosed in the description, the claims, the figures, or elsewhere, also individually define essential components of the invention, even if they are described together with other features. In all figures, the same reference numerals represent the same objects, so that descriptions of objects that may only be mentioned in one figure, or at least not with respect to all figures, can also be applied to those figures and embodiments for which the object is not explicitly described in the description. Reference symbol list

[0074] 1 Electrostatic air filter device 2 Ionizer 3 Air particles 4 Collector 5 Ionized air particles 6 Pre-filter 7 Incoming air 8 Final filter 9 Air flowing out of the collector 10 First electrode of the ionizer 11 Second electrode of the ionizer 12 First electrode of the collector 13 Second electrode of the collector 14 Pre-filtered air 20 Control circuit 21 (Adjustable) electrical power source 22 Voltage meter or voltage regulator for the voltage applied to ionizer 2 23 Current meter for the current flowing through ionizer 2 24 Current meter for the current flowing through collector 4 25 Voltage meter or voltage regulator for collector 4 26 Power control (voltage regulator) 27 Control 28 Display unit 29 Input unit 100 Procedure 110 Procedure step 120 Procedure step 130 Procedure step

Claims

1. Electrostatic air filter device (1) for filtering air flowing through the electrostatic air filter device, comprising: - an ionizer (2) for ionizing air particles (3) in an electrostatic ionizer field generated by applying an electrical voltage supplied by a controllable electrical power source (21) to the ionizer (2), - a collector (4) for capturing air particles (5) ionized in the ionizer (2) in an electrostatic collector field generated by applying an electrical voltage supplied by the controllable electrical power source to the collector (4), - an electrical control circuit (20) for controlling the controllable electrical power source (21), wherein the electrical control circuit (20) is configured to detect at least one current power parameter of the ionizer (2) and / or the collector (4) for determining a current state of the ionizer (2) and / or the collector (4),and to adjust the electrical power source (21) at least partially based on the detected at least one current power parameter, so that the electrostatic ionizer field and / or the electrostatic collector field can be adjusted taking into account the current state of the ionizer (2) and / or the collector (4).

2. Electrostatic air filter device (1) according to claim 1, wherein the at least one current performance parameter of the ionizer (2) and / or the collector (4) comprises an electric current currently flowing through the ionizer (2) and / or the collector (4), and / or wherein the condition is a degree of pollution of the ionizer (2) and / or the collector (4).

3. Electrostatic air filter device (1) according to one of the preceding claims, wherein the electrical control circuit (20) is configured to regulate an ionization volume provided in the ionizer (2) in response to a change in state, in particular to adjust it such that the ionization efficiency provided for particles (3) passing through the ionizer (2) remains constant over time, and / or wherein the electrical control circuit (20) is configured to regulate a collector volume provided in the collector (4) in response to a change in state, in particular to adjust it such that the capture efficiency provided for ionized particles (5) passing through the collector (4) remains constant over time.

4. Electrostatic air filter device (1) according to one of the preceding claims, wherein the electrical control circuit (20) is configured to reduce an output voltage of the electrical power source (21) when an increase in at least one power parameter indicating contamination of the ionizer (2) and / or the collector (4) with electrically conductive particles is detected.

5. Electric air filter device (1) according to claim 3 or 4, wherein the electrical control circuit (20) is configured to reduce the output voltage of the electrical power source (21) while maintaining a substantially constant electrical power.

6. Electrostatic air filter device (1) according to one of the preceding claims, wherein the electrical control circuit (20) is configured to increase an output voltage of the electrical power source (21) when a drop in at least one performance parameter is detected, indicating contamination of the ionizer (2) and / or the collector (4) with electrically non-conductive particles (3, 5).

7. Electrostatic air filter device (1) according to one of the preceding claims, wherein when adjusting the electrical power source, a current electrical power of the ionizer (2) and / or the collector (4) is used as a control parameter.

8. Electrostatic air filter device (1) according to one of the preceding claims, wherein the electrostatic air filter device comprises an output device (28) for outputting a current value of the at least one performance parameter of the ionizer (2) and / or the collector (4) and / or for outputting a state of the electrostatic air filter device.

9. Electrostatic air filter device (1) according to one of the preceding claims, further comprising an ammeter (23) in the current path of the ionizer (2) for detecting the current flowing through the ionizer, and / or further comprising an ammeter (25) in the current path of the ionizer (4) for detecting the current flowing through the ionizer.

10. Electric air filter device (1) according to one of the preceding claims, further comprising a control (27) which has at least one of the following means: - means for detecting the at least one performance parameter, for example by evaluating the measured values ​​obtained with the ammeter (23) and voltage meter (22) and / or the measured values ​​obtained with the ammeter (25) and voltage meter (24), - means for controlling the electrical power source (21), in particular by means of a voltage regulator (26), - means for outputting the state, in particular by means of the output device (28).

11. Electrostatic air filter device (1) according to the preceding claims, further comprising at least one interface, in particular for the control (27) defined in the preceding claim, wherein the interface is configured - for receiving current measured values ​​of at least one measuring device (22), (23), (24), (25), and / or - for outputting control signals for controlling the electrical power source (21), and / or - for receiving user inputs, in particular from a user interface (29), and / or - for outputting status information, in particular to a display device (28).

12. Method for operating an electrostatic air filter device (1) according to one of the preceding claims, comprising: - generating (110) an electrostatic ionizer field in the ionizer (2) by applying an electrical voltage generated by a controllable electrical power source (21) to the ionizer (2), - generating (115) an electrostatic collector field in the collector (4), - detecting (120) at least one current power parameter of the ionizer (2) and / or the collector (4) to determine a current state of the ionizer (2) and / or the collector (4), and - adjusting (130) the power source at least partially based on the at least one current power parameter, so that the electrostatic field of the ionizer and / or the collector can be adjusted taking into account the current state of the ionizer and / or the collector.

13. Method according to the preceding claim, wherein applying the voltage to the ionizer comprises applying an initial voltage below a voltage threshold.

14. Method according to claim 12, wherein the application of the voltage comprises imprinting an initial power below a power threshold.

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