DE102021111870A1 - functional check - Google Patents

Abstract

Method for checking the function of the operating parameters of an electrohydrodynamic atomizer (1), with an electrohydrodynamically atomized fluid starting from the atomizer (1) being applied to a body (91), e.g. a person, in order to coat this body (91) at least in sections, wherein the atomizer (1) comprises a fluid tank for storing the fluid and at least one high-voltage source for providing a high voltage and at least one pump unit for transporting the fluid, the fluid being conveyed to a nozzle arrangement (12) of the atomizer (1) by means of the pump unit, wherein the fluid is atomized electrohydrodynamically at the nozzle arrangement (12) by the action of the high voltage from the high-voltage source, and particles (7) of the atomized fluid charged on the atomizer (1) are trapped by means of a trap (2) and a voltage and/or a current is detected via this trap (2) in order to generate a current-voltage Ke nnlinie (10) or a family of characteristics to act on an operating point (A0, A1, A2, A3, A4, A5) of the high-voltage source and/or the electrohydrodynamic atomizer (1).

Description

The invention relates to a method for checking the function of the operating parameters of an electrohydrodynamic atomizer of fluids according to the preamble of claim 1.

Electrohydrodynamic atomization is based on the instability of electrically chargeable fluids, in particular fluids that are sufficiently electrically conductive under high voltage, in a strong inhomogeneous electric field. For this purpose, the fluid is subjected to high voltage. The fluid is deformed into a cone, from the tip of which a thin stream, a so-called jet, is emitted, which then immediately breaks up into a spray of finely dispersed droplets or charged particles. Under certain conditions, in the Taylor cone mode, the droplets have a narrow size distribution. Because very high electric field strengths are required for atomization, it is advantageous to check the function within specified operating parameters in order to avoid undesirable electrostatic charges.

Methods for checking the function of electrohydrodynamic atomizers of fluids are known from the prior art. From the German patent application DE 10 2018 133 439.7 a method is known which uses electrohydrodynamic atomization to apply care products to a body, for example a person, in order to coat this body at least in sections.

For this purpose, the atomizer comprises a fluid tank for storing the fluid and at least one high-voltage source for providing a high voltage and at least one pump unit for transporting the fluid. The fluid is conveyed by the pump unit to a nozzle arrangement of the atomizer, with the fluid being electrohydrodynamically atomized at the nozzle arrangement by the action of the high voltage from a high-voltage source. A voltage and/or a current provide information about the operating state of the high-voltage source and are evaluated in order to detect an operating point of the high-voltage source via a current-voltage characteristic or a family of characteristics.

The disadvantage here is that during use, ie during spraying, only insufficient information is available for functional control of the operating parameters, for example about the quality of the atomization and/or the quality of the coating. For example, if the nebulizer is aimed at an ungrounded body or in the void, no evaluable information is available to check the function of the electrohydrodynamic nebulizer.

The invention is therefore based on the object of developing a method for checking the function of devices of this type, by means of which sufficient information is made available for a largely uninterrupted function check.

Starting from the features of the preamble of claim 1, this object is achieved by the characterizing features of claim 1. Advantageous and expedient developments are specified in the respective dependent claims.

Within the meaning of the invention, a trap is to be understood as meaning an electrical sensor mass and/or a (sensor) measuring field and/or an electrically attractive target that is grounded and/or an electrical attractant mass.

• - Von einem Zerstäuber ausgehend wird ein elektrohydrodynamisch zerstäubtes Fluid auf einen Körper, beispielsweise eine Person, aufgetragen, um diesen Körper zumindest abschnittsweise zu beschichten,
• - der Zerstäuber umfasst
  • - einen Fluidtank zur Bevorratung des Fluids und mindestens eine Hochspannungsquelle zur Bereitstellung einer Hochspannung sowie
  • - mindestens eine Pumpeinheit zum Transport des Fluids,
• - wobei das Fluid mittels der Pumpeinheit zu einer Düsenanordnung des Zerstäubers gefördert wird und
• - wobei das Fluid an der Düsenanordnung mittels Einwirkung der Hochspannung aus der Hochspannungsquelle elektrohydrodynamisch zerstäubt wird,
• - wobei es dabei zur Funktionskontrolle vorgesehen ist, dass geladene Partikel des zerstäubten Fluids mittels einer Falle an dem Zerstäuber eingefangen werden und dass eine Spannung und/oder ein Strom über diese Falle erfasst wird bzw. werden, um über eine Strom-Spannungs-Kennlinie oder ein Kennlinien Feld auf einen Arbeitspunkt der Hochspannungsquelle und/oder des elektrodynamischen Zerstäubers einzuwirken.

The procedure for functional control of the operating parameters of an electrohydrodynamic atomizer includes the following steps:

• - Starting from an atomizer, an electrohydrodynamically atomized fluid is applied to a body, for example a person, in order to coat this body at least in sections,
• - the nebulizer includes
  • - A fluid tank for storing the fluid and at least one high voltage source for providing a high voltage and
  • - at least one pump unit for transporting the fluid,
• - wherein the fluid is conveyed by means of the pump unit to a nozzle arrangement of the atomizer and
• - the fluid being atomized electrohydrodynamically at the nozzle arrangement by means of the action of the high voltage from the high-voltage source,
• - Whereby it is provided for functional control that charged particles of the atomized fluid are captured by a trap on the atomizer and that a voltage and / or a current is detected via this case or are, to a current-voltage characteristic or a characteristic field to act on an operating point of the high-voltage source and/or the electrodynamic atomizer.

The trap can, for example, by means of a conductive and an electrical resistance grounded surface can be realized. This makes it an electrostatically attractive target for the charged particles of the atomized fluid when sprayed on an ungrounded body, such as a person, or in space. As a result, an operating point of the high-voltage source and/or the electrohydrodynamic atomizer can be detected via a current-voltage characteristic or a family of characteristics. This allows information about the quality of the atomization and the coating of the body to be coated, for example a person, to be obtained during operation. This information can be used to optimize atomizer operation and improve coating quality. Accordingly, a largely uninterrupted functional control of the operation of an electrohydrodynamic atomizer is possible with this method. For example, it is conceivable that in the unfavorable coating case the particles do not land on the body to be coated, although the high-voltage source is working in the optimum range and without this error being noticeable in the current-voltage characteristic of the high-voltage source. Instead, the particles land on the trap, making the bug noticeable. Electrohydrodynamic atomization uses the effect of high voltage, which causes charges to be transferred to the fluid and from it, in an unfavorable mode of operation, to the trap. A measurement of current and/or voltage at the trap and a comparison of this measurement result with a current-voltage characteristic of the high-voltage generator allows statements to be made about the current load on the high-voltage source. Values are relevant here, in particular as to whether a current flow to the trap can be recorded and the trap thus captures the charges applied via the charged particles. If a desired low current flow to the trap is recorded when high voltage is applied, correct coating takes place and a correspondingly reduced backflow of the applied charges from the trap to the high-voltage source and/or the atomizer. The evaluable charge generated on the trap and its signal can be used to provide information, for example regarding the spray mode of the atomizer, and if, for example, the current flow to the trap becomes too great, to trigger device reactions, such as stop spraying, display elements such as such as LEDs, vibrations or sounds, or information for applications on computers, mobile phones or similar.

Furthermore, it is provided that the evaluated voltage and/or the current at the trap correspond to a reference voltage and/or a reference current proportional to the actual voltage value and/or current value of the high-voltage source. By using reference variables, the current operating parameters of the atomizer can be related to the target parameters of the atomizer and the operation can be adjusted accordingly. By using a reference voltage and/or a reference current, the possibility of simpler detection and evaluation is given, since high voltages do not have to be fed directly to measurement electronics. A reference voltage and/or a reference current value is provided by the high-voltage source, which is preferably tapped off during high-voltage generation and does not directly load the high-voltage circuit used for the atomization itself through the measurement.

Furthermore, the nebulizer can be held in the hand of a user. A current flow from the high-voltage source is detected and evaluated via the atomized fluid through the body to be coated and the hand of the user via hand contact elements on the atomizer back to the high-voltage source. The current flow is then compared to a voltage or a current across the trap to be evaluated. In this way, a control of the normal current flow during operation of the device can be related to an unintended mode of operation, for example spraying into the void.

It is known from the prior art that the simplest variant of a closed electric circuit for avoiding unwanted charging and for checking the function of the electric atomizer is given by the contact closure via the user's hand. Structurally, conductive contact elements are provided for this purpose, for example on a plastic housing, which are always freely accessible during normal use. For example, control buttons or corresponding control elements are suitable for this purpose.

According to the invention, an alternatively closing circuit is formed by a trap, for example a charge-catcher electrode. For example, a flat trap on the back of the atomizer is a good design option. The current that flows by means of the charged particles via the body to be sprayed, for example a person, and the hand of the user into the high-voltage source and/or the atomizer can be combined with the current of the charged particles via the trap into the high-voltage source and/or or the atomizer flows can be set in a ratio to be evaluated. This makes it possible to draw conclusions about the quality of the atomization and/or the coating of the body to be sprayed, for example a person, and the operation The condition of the atomizer can be adjusted accordingly and the atomization or coating can be optimized even if the atomizer is spraying an ungrounded body or into the void, as in this case a larger proportion of the particles will end up in the trap.

Provision is also made for a plurality of operating points to be defined on a current-voltage characteristic of the high-voltage source. The recorded actual operating point at the high-voltage source is compared with one of the other operating points. At least the actual operating point at the high-voltage source can also be detected lying in a range on the current-voltage characteristic of the high-voltage source between two operating points.

The advantage here is that an exact classification of the actual operating point is not absolutely necessary. Rather, it is sufficient to classify a detected actual operating point in a target operating range, which is defined by the target operating points that limit it. For example, a low current value, which is still sufficient to transport the charges sufficiently away from the body to be coated, can define a first target operating point and a high current value, which loads the voltage source and thus leads to a drop in the amount of high voltage, where electrohydrodynamic atomization is still possible, define a second target working point between which the target working range of the atomizer is located.

Provision is also made for a target working range to be defined on the current-voltage characteristic of the high-voltage source, with a fault being signaled if the detected actual working point lies outside of the target working range.

On the basis of this information, an operating state can be initiated at the nebulizer, for example a shutdown, which ensures that the nebulizer can be used in previously defined parameters. A corresponding state can occur if malfunctions or incorrect operation occur, for example when the atomizer is put down or if, for example, external influences prevent the charged particles from escaping from the nozzle arrangement. An uncontrolled operating state of the atomizer can thus be prevented.

Furthermore, the execution of a regular detection of the operating point is provided. A detected operating point is compared to at least one previously detected operating point in order to detect a change in the operating point.

It is thus possible to recognize a suboptimal operating state at an early stage in order to be able to change the operating parameters before an undesirable operating mode occurs, or to be able to switch off the system. Since the working point during operation is heavily dependent on direct geometric and environmental influences, such as the position or guidance of the atomizer, with an associated change in the distance between the atomizer and the body to be coated, for example a person, a fluctuation in the working point can also be determined whether the atomizer is being used, i.e. being moved, or is lying still. If the operating point remains the same over a number of time cycles or remains within a specified tolerance range, the atomizer malfunctions, since atomization or coating takes place without there being a planar application to the body to be coated. In this way, for example, a malfunction can be avoided when the nebulizer is put down.

Furthermore, the triggering of a defined user information and/or device reaction, for example a shutdown by the operating point detected, is provided, which is stored in a memory as a function of the position of the operating point on the current-voltage characteristic.

Due to the geometry and environmental influences, which are integrated into the circuit for determining the working point, there is the possibility of recognizing characteristic working points at which user information can be queried from a memory. For example, a direct contact between the atomizer, skin surface and trap can be brought about during a switch-on process, resulting in a characteristic working point for this user. As a result, completely individual and different working points for several users can be selected in order to always enable an optimal operating state of the atomizer for different needs. Different working points are conceivable using the example of atomizing skin lotions, where different users have different needs due to their individual skin properties, which can be taken into account by the atomizer. The trap can also be used to identify and correct individual operating errors by detecting a drop in the operating point on the current-voltage characteristic due to an excessive distance between the device and the body to be coated, for example a person and an indication thereof is displayed by the nebulizer.

Provision is also made for detecting a switch-on curve of the high-voltage source, with the switch-on curve ending at an operating point.

This makes it possible to determine the state in which the electrohydrodynamic atomizer should initially be operated.

In this way, measures can be taken at an early stage, which are assigned to the operating point that has started, even before this operating point is reached. For example, the high voltage or the pump can be blocked if an operating point outside the functional range is controlled via the switch-on curve.

Provision is also made for the evaluated voltage and/or the current to be corrected using at least one correction parameter in such a way that a direct current flow and/or a direct voltage drop between the nebulizer and the hand of the user operating the nebulizer can be detected and preferably Disturbance can be evaluated.

The problem is that due to the given spatial proximity between the hand of the user operating the atomizer and the atomized fluid, a significant current flow or voltage drop occurs directly between the holding hand and the atomizer without this contributing to the coating result. The influence of the direct current flow and/or the direct voltage drop between the nebulizer and the hand of the user operating the nebulizer can be detected via at least one correction parameter, for example by a calibration operation or a measurement pulse. A disturbance variable or the like, for example, can then be determined via this at least one correction parameter, which is included in the method for checking the function.

The invention also provides a high-voltage source for carrying out one of the processes described above, in which a low-voltage signal proportional to the high voltage emitted can be tapped off as a reference voltage.

With such a high-voltage source, it is possible to protect the measuring electronics from the high voltage and to design the evaluations for the low-voltage signal that is proportional thereto. As a result, costs can be saved in the design of the measuring electronics and in the manufacture of the device.

The invention also provides an electrohydrodynamic atomizer. The electrohydrodynamic atomizer according to the invention comprises a fluid tank for storing a fluid and at least one high voltage source for providing a high voltage and at least one pump unit for transporting the fluid. The fluid is conveyed by the pump unit to a nozzle arrangement of the atomizer, with the fluid being electrohydrodynamically atomized at the nozzle arrangement by the action of the high voltage from the high-voltage source. A trap is attached to the surface of the nebulizer, which trap is designed in particular in the form of an electrode.

This makes it possible to obtain additional information about the operating status of the atomizer independently of the electrical properties of the body to be coated.

The latch is particularly preferably arranged outside the gripping area. This is necessary to prevent the trap from being unintentionally covered by a user's hand.

According to the invention, the electrode of the electrohydrodynamic atomizer is grounded via a resistance between 1 kOhm and 20 kOhm, in particular between 5 kOhm and 15 kOhm, preferably between 9 kOhm and 11 kOhm.

A user's grounded hand can also provide an attractive target for the charged particles in addition to the trap. In order to prevent this, the resistance used on the electrode has a size that optimizes the collection of the charged particles in favor of the trap. The electrode thus acts as an attractive target for charged particles and can collect the charges to obtain information about the operating status. An undesired direct charge transport via the user's hand is thereby reduced or avoided.

The electrode of the electrohydrodynamic atomizer according to the invention is connected to a filter and an operational amplifier for the output of a signal.

The information on the current and/or the voltage of the charged particles can thus be further processed and evaluated. In this way, a functional control of the operating parameters of the nebulizer can be made possible in an improved manner within the meaning of the invention.

The concept of characteristic in the sense of the invention also includes data collections from Kennda ten to understand which can be compared with detected operating points to perform the function check according to the invention.

For the purposes of the present invention, electrostatic atomization includes all atomization processes which atomize liquids with the effects of exposure to high voltage. In particular, electrohydrodynamic effects and electrokinetic effects are also included in the term of this type of atomization. For the purposes of the invention, electrostatic atomization can also be understood to mean electrohydrodynamic atomization.

The arrangement of nozzles on the high-voltage source means any interaction that enables electrostatic, in particular electrohydrodynamic, atomization by high voltage. A nozzle arrangement can consist of conductive material, but also of non-conductive material in order to bring about the necessary effects.

Within the meaning of the invention, a fluid is to be understood as any liquid that is suitable for application by electrostatic atomization. According to the invention, it is provided in particular that the liquid is a cosmetic, for example a sunscreen, a lotion, a deodorant. The liquid can also be a liquid paint, varnish or the like. Other liquids, for example an insect repellent or a disinfectant, are also conceivable.

Further details of the invention are described in the figures using schematic exemplary embodiments.

• 1 eine schematische Darstellung eines erfindungsgemäßen Zerstäubers beim Besprühen eines nicht-geerdeten Körpers, bzw. ins Leere;
• 2 eine schematische Darstellung eines erfindungsgemäßen Zerstäubers beim Sprühen auf einen geerdeten Körper und
• 3 eine schematische Darstellung einer Strom-Spannungs-Kennlinie.

This shows:

• 1 a schematic representation of an atomizer according to the invention when spraying an ungrounded body, or into the void;
• 2 a schematic representation of an atomizer according to the invention when spraying on a grounded body and
• 3 a schematic representation of a current-voltage characteristic.

In 1 the use of an electrohydrodynamic atomizer 1 is shown. Starting from the atomizer 1, a fluid electrohydrodynamically atomized at a nozzle arrangement 12 is applied or sprayed onto a body (not shown) that is not connected to the ground potential 6 or into the void. Due to an electrohydrodynamic atomization process at the nozzle arrangement 12, the particles 7 produced carry a charge, which is captured by means of a trap 2 for electrical charges, in particular a conductive surface, in particular a charge-catcher electrode, and a voltage and/or current via this trap 2 is evaluated. this in 3 The voltage U and/or current I shown provides information about an operating state of the nebulizer 1.

In the 3 The voltage U shown and the current I can be converted into a signal 5 at the atomizer 1 with the aid of a filter and operational amplifier 4 and evaluated. In the case shown here, there is no body within reach of the atomized fluid or the charged particles 7 which, like the atomizer 1, would be connected to the ground potential 6.

The trap 2 is in contact with the ground potential 6 by means of an electrical resistor 3 between 1 kOhm and 20 kOhm, in particular between 5 kOhm and 15 kOhm, preferably between 9 kOhm and 11 kOhm. As a result, the trap 2 represents an attractive target for the charged particles 7 and environmental influences, such as from the user's hand 91, are minimized.

in the in 1 case shown, very many charged particles 7 land on the trap 2. This makes it possible to measure information about the quality of the atomization and the coating of the body to be coated 92, for example a person, during operation even if this body is not electrically connected to the Atomizer 1 is contacted or grounded. This information can be used to optimize the operation of the atomizer 1 and to improve the coating or to trigger a fault, for example when spraying into the void.

In 2 is shown schematically the case when in contrast to 1 is sprayed onto a grounded body 91 instead of onto a non-grounded body (not shown) or into the void. Depending on the distance 8 between the atomizer 1 and the grounded body 91, the trap 2 will catch far fewer charged particles 7, which becomes noticeable in a difference in the signal 5. The differences in the signal 5 provide information about the operating state of the electrohydrodynamic atomizer 1, as a result of which the operating parameters and the correct function can be checked. The strength and/or height of the detected and converted into a signal 5 and in 3 shown current I and / or voltage U and sensitively depend on direct geometric and environmental influences, such as posture and guidance of the nebulizer 1 by the hand 92 of the user.

The atomizer 1 is held in the hand 92 of a user and a current flow 95 from the high-voltage source via the atomized fluid and the body 91 to be sprayed, for example a person, through the user's hand 92 via hand-contact elements 13 on the atomizer 1 back to the high-voltage source recorded and evaluated, and with an in 3 voltage U shown and/or a current I across the trap in a ratio to be evaluated.

Looking at the two together 1 and 2 For example, spraying of a non-grounded body (not shown) or spraying into the void can be seen as spraying of a grounded body 91 that is far away and on which the particles can no longer reach due to the distance 8 that is too great. Despite the absence of a body 91 that is grounded or in electrical contact with the nebulizer, for example a person, is provided by the trap 2 within the reach of the nebulizer 1, information about the operating status and the not shown here and in 3 shown operating point A0, A1, A2, A3, A4, A5 (in 3 shown) of the nebulizer in operation.

3 shows a schematic current-voltage characteristic 10 for functional control of the operating parameters according to the invention in the 1 and 2 illustrated electrohydrodynamic atomizer 1. A voltage U and / or a current I are recorded at a high-voltage source or determined and evaluated using reference variables. In the case of reference variables in particular, the voltage and/or the current supplies a reference voltage and/or a reference current that is proportional to the actual voltage value and/or current value of the high-voltage source.

As a result, a voltage that is proportional to the high voltage but lower can be evaluated, which enables a simpler construction of the electronics.

A plurality of operating points A0, A1, A2, A3, A4, A5 on the current-voltage characteristic are defined. The detected actual working point, for example A3, at the high-voltage source is compared with a working point, or at least in a region 11 on the current-voltage characteristic 10 between two working points, for example A2 and A4, is detected.

A concrete classification of the operating point A3 can be avoided in this way and it is sufficient to assign this operating point, for example A3, to a target operating range 11 alone. If the working point, for example A1, is outside of the target working range 11, a fault can be signaled, which ensures safe and reliable operation within the working range 11.

Periodic acquisition of the operating point and storage of at least one previously acquired operating point is performed, wherein an acquired operating point is compared to at least one previously acquired operating point to detect a change in operating points and possibly analyze a trend. As a result, an undesired operating state can be detected at an early stage and the operating parameters can be changed before it occurs. In addition, as described above, normal operation of the atomizer can also be recognized by the operating points fluctuating around a mean value within the operating range 11, which is attributable to the variation in distance in normal operation.

The detected operating points A0, A1, A2, A3, A4, A5 can trigger defined user information and/or device response, for example a shutdown, which is stored in a memory depending on the position of the operating point on the current-voltage characteristic 10 .

Individual needs of different users can thus be automatically taken into account during use.

A switch-on curve 14 of the high-voltage source is recorded and ends in an operating point, for example A3. Here, measures can be taken at an early stage, which are assigned to the working point, for example A3.

The evaluated voltage and/or the current are corrected using at least one correction parameter in order to correct individual influences, for example the user's hand (not shown), or environmental influences, for example high humidity or other circumstances.

Reference List

1

atomizer

2

Cases

3

electrical resistance

4

filters and operational amplifiers

5

signal

6

earth potential

7

charged particles

8th

Distance

91

Body

92

hand

95

current flow

10

Current-voltage characteristic

11

target workspace

12

nozzle arrangement

13

hand contact elements

14

switch-on curve

A0-A5

operating point

u

tension

I

electricity

QUOTES INCLUDED IN DESCRIPTION

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

Patent Literature Cited

• DE 102018133439 [0003]

Claims (13)

Method for checking the function of the operating parameters of an electrohydrodynamic atomizer (1), - an electrohydrodynamically atomized fluid, starting from the atomizer (1), being applied to a body (91), for example a person, in order to coat this body (91) at least in sections, - wherein the atomizer (1) comprises a fluid tank for storing the fluid and at least one high-voltage source for providing a high voltage and at least one pump unit for transporting the fluid, - wherein the fluid is conveyed to a nozzle arrangement (12) of the atomizer (1) by means of the pump unit - and the fluid is atomized electrohydrodynamically at the nozzle arrangement (12) by the action of the high voltage from the high-voltage source, characterized in that charged particles (7) of the atomized fluid are captured on the atomizer (1) by means of a trap (2). and a voltage (U) and/or a current (I) across this trap (2) is detected in order to act on an operating point (A0-A5) of the high-voltage source and/or the electrohydrodynamic atomizer (1) via a current-voltage characteristic (10) or a family of characteristics. procedure after claim 1 , characterized in that the evaluated voltage (U) and/or the current (I) forms a reference voltage and/or a reference current proportional to the actual voltage value and/or current value of the high-voltage source. procedure after claim 1 or 2 , characterized in that the atomizer (1) is held in the hand (92) of a user and a current flow from the high-voltage source via the atomized fluid through the hand (92) of the user via hand-contact elements (13) on the atomizer (1) is recorded and evaluated back to the high-voltage source and is set in a ratio to be evaluated with a voltage (U) or a current (I) via the trap (2). procedure after claim 1 , 2 or 3 , characterized in that a plurality of operating points (A0-A5) are defined on the current-voltage characteristic (10) of the high-voltage source, the detected actual operating point (A3) on the high-voltage source being compared with an operating point (A0-A5). is detected, or at least in a region (11) lying on the current-voltage characteristic (10) of the high-voltage source between two operating points (A2, A3). Method according to one of the preceding claims, characterized in that a target working range (11) is defined on the current-voltage characteristic (10) of the high-voltage source, in which case the detected actual working point (A2) is outside the target -working area (11), a fault is signalled. Method according to one of the preceding claims, characterized in that a regular detection of the working point (A0-A5) is carried out, a detected working point (A3) being compared with at least one previously detected working point (A0-A5) in order to determine a change in the working point to recognize. Method according to one of the preceding claims, characterized in that the detected working point (AO-A5) triggers a defined user information and/or device reaction, for example a shutdown, which depends on the position of the working point (A0-A5) on the current Voltage characteristic (10) of the high-voltage source is stored in a memory. Method according to one of the preceding claims, characterized in that a switch-on curve (14) of the high-voltage source is detected, the switch-on curve (14) ending in an operating point (A3). Method according to one of the preceding claims, characterized in that the evaluated voltage (U) and/or the current (I) is corrected via at least one correction parameter in such a way that a direct current flow and/or a direct voltage drop between the atomizer (1) and the hand (91) of the user, which operates the nebulizer (1), can be detected and can preferably be evaluated as a disturbance variable. High-voltage source for carrying out a method according to one of the preceding claims, characterized in that a low-voltage signal proportional to the high voltage emitted can be tapped as a reference voltage. Electrohydrodynamic atomizer (1), this comprising a fluid tank for storing a fluid and at least one high-voltage source for providing a high voltage and at least one pump unit for transporting the fluid, the fluid being conveyed to a nozzle arrangement (12) of the atomizer (1) by means of the pump unit and wherein the fluid is atomized electrohydrodynamically at the nozzle arrangement (12) by means of the action of the high voltage from the high-voltage source, characterized in that it has a surface on the atomizer (1) attached trap (2), in particular in the form of an electrode. Electrohydrodynamic atomizer (1) after claim 11 , characterized in that the electrode is grounded via a resistor (3) between 1 kOhm and 20 kOhm, in particular between 5 kOhm and 15 kOhm, preferably between 9 kOhm and 11 kOhm. Electrohydrodynamic atomizer (1) according to one of the preceding claims, characterized in that the electrode is connected to a filter and an operational amplifier (4) for the output of a signal (5).

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