EP3898001A1

EP3898001A1 - Function control for an electrohydrodynamic atomizer

Info

Publication number: EP3898001A1
Application number: EP19832357.8A
Authority: EP
Inventors: Sebastian Mangold; Manuel FIESEL; Jens Ulbrich; Thomas Jeltsch; Alfred Göhring; Jan Barthelmes
Original assignee: J Wagner GmbH
Current assignee: J Wagner GmbH
Priority date: 2018-12-21
Filing date: 2019-12-19
Publication date: 2021-10-27
Also published as: JP2022514928A; CN113453805B; KR102602048B1; KR20210107776A; CN113453805A; WO2020127712A1; DE102019135147A1; US20220016649A1

Abstract

The invention relates to a method for the function control of an electrohydrodynamic atomizer (20), wherein an electrohydrodynamically atomized fluid (23) originating from the atomizer (20) is applied to a body, for example, a person, in order to coat said body at least in sections, wherein the atomizer (20) comprises a fluid tank for storing the fluid (23) 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 (23) is conveyed by means of the pump unit to a nozzle arrangement of the atomizer (20), and wherein the fluid (23) is electrohydrodynamically atomized at the nozzle arrangement by means of the effect of the high voltage from the high voltage source, wherein a voltage and/or a current at the high voltage source is evaluated, in order to detect a working point of the high voltage source via a current-voltage characteristic curve.

Description

Function check for an electrohydrodynamic atomizer

State of the art:

Electrohydrodynamic atomization of fluids is becoming increasingly important in the field of coating processes.

For example, a device is known from PCT / EP2018 / 060117 which, using electrohydrodynamic atomization, e.g. Applying care products such as sunscreen to a person's body.

Methods are known from the prior art

known electrohydrodynamic atomization of fluids.

Electrohydrodynamic atomization is based on the

Instability of electrically chargeable fluids, particularly fluids that are sufficiently electrically conductive under high voltage, in a strong inhomogeneous electrical field. A high voltage is applied to the fluid. The fluid deforms into a cone, from the tip of which a thin jet, a so-called jet, is emitted, which then immediately breaks down into a spray of finely dispersed drops. Under certain conditions, in the Taylor-Kegel mode, the drops have a narrow size distribution. Because very high electrical field strengths are required for atomization, a functional check is advantageous in order to avoid undesired electrostatic charges. The object of the invention is therefore to provide a functional check for such devices in order to avoid undesirable effects from electrohydrodynamic atomization.

This object is achieved by a method for checking the function of an electrohydrodynamic atomizer after

Protection claim 1 solved.

In the following the invention and its advantageous

Further developments and designs are explained with reference to the current-voltage characteristic curve from FIG. 1.

Various are also exemplary

Coating situations shown in Figures 2a to 2d.

It starts from the atomizer

electrohydrodynamically atomized fluid applied to a body, e.g., a person, at least around that body

to be coated 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 converted into a nozzle arrangement by the pump unit

The atomizer is conveyed, the fluid being atomized electrohydrodynamically at the nozzle arrangement by the action of the high voltage from the high voltage source.

To check the function, it is provided that a voltage U and / or a current I is evaluated at the high-voltage source in order to use a current-voltage characteristic curve 10

Working point Al, A2, A3, A4 to detect the high voltage source. Electrohydrodynamic atomization uses the action of a high voltage, as a result of which charges are transferred to the fluid and from there to the body to be coated. A measurement of current and / or voltage and a comparison of this measurement result with a current-voltage characteristic curve (10) allows statements to be made about the load on the high-voltage source, in particular as to whether there is a current flow and thus a coated body over the Coating applied charges also releases again. If there is a desired current flow when high voltage is present, the coating applied is correctly applied and the applied charges flow back to the atomizer. Each combination of current and voltage values that can be achieved by the system during operation therefore defines an operating point in the current-voltage characteristic.

In a preferred embodiment it is provided that the evaluated voltage u and / or the current I one for

actual voltage value and / or current value of the

High voltage source is proportional reference voltage and / or a reference current.

By using a reference voltage and a reference current, the possibility of a simple detection and

Evaluation given because no high voltages directly one

Measuring electronics must be supplied. It is from the

High voltage source a reference voltage and / or a

Reference current value is provided, which is preferably tapped during the generation of high voltage and does not directly load the high-voltage circuit used for the atomization itself. In an advantageous embodiment, as shown for example in FIG. 2a, the atomizer 20 in the hand 22 is one

User 21 held and a current flow from the

High voltage source via the atomized fluid 23, e.g. on the arm 24 over the body of the user 21 through the hand 22 of the user via hand contact elements on the atomizer 20 back to the high voltage source is detected and evaluated.

The simplest variant of a closed circuit 28 to avoid undesired charging and to check the function of the electrohydrodynamic atomizer 20 is through the

Contact closure given by the user's hand. In terms of construction, e.g. conductive on a plastic housing

Contact elements are provided, which are always touched during normal use. For this, e.g.

Control buttons or corresponding controls.

In particular, the method provides that a

A plurality of operating points A0 to A5 are defined on the current-voltage characteristic curve, the actual working point detected - e.g. corresponding to A3 - is compared at the high-voltage source with an operating point of the characteristic curve A0 to A5, or at least recorded in an area 11 on the current-voltage characteristic curve 10 between two working points A2, A4.

The advantage here is that it is not necessarily an exact one

Classification of the working point A3 is required. Rather, it is sufficient to classify a detected working point A3 in an area 11, which is defined by target working points A2, A4 delimiting a desired working area. For example, a low current value can be used, which is still sufficient to adequately remove the charges from the coated body transport, define a first target operating point A2, and a high current value, which loads the voltage source and thus leads to a decrease in the amount of high voltage, wherein electrohydrodynamic atomization is still possible, define a second target operating point A4, between which the working range 11 of the atomizer lies.

In addition, it is preferably provided that a working area 11 is defined on the current-voltage characteristic curve, a fault 40 being signaled in the event that the detected working point lies outside of this desired working area 11.

A corresponding state is shown in Fig. 2d. A first person 41 uses an atomizer 42 to apply a fluid to a second person 43. Because of the open

Circuit 44, no current flow I is achieved and the

Working point Al or another working point in the fault area 12 is reached. The electrohydrodynamic

Atomizer will signal a malfunction 40 since proper functioning cannot take place. This situation occurs e.g. when the base 45 on which the people 41, 43 stand is a sufficient insulator and the people are not shown in Fig. 2c, connect by touch 46 to form a closed circuit 47

enable .

In the variant shown in FIG. 2c, the working point A3 will be in the working area 11, so that atomization 48 takes place.

An expedient development of the method provides that the working point is recorded regularly, b wherein a detected working point A3 is compared with at least one previously recorded working point A3 'in order to detect a change in the working point.

Because the working point in operation is very different from the immediate

Geometric influences such as Distance of the atomizer 20 from the object to be coated, e.g. depends on the arm 24 in Fig. 2a, it can also be determined via a fluctuation in the working point whether the atomizer is used, that is, moved. If the working point remains the same or within a defined tolerance range over several time cycles, the atomizer will malfunction because atomization or coating takes place without a flat application to the object to be coated. In this way e.g. a malfunction when storing the

Atomizer to be avoided.

A further development also provides that the recorded working point triggers a defined user information, which in

Dependence on the position of the operating point on the current-voltage characteristic is stored in a memory.

Due to the physical line properties of the user, who is integrated in the circuit for determining the operating point, there is the possibility of characteristic

Recognize operating points at which user information can be queried from a memory. E.g. can be a direct contact between the atomizer and skin surface in a

Switch-on process are brought about, by which a characteristic operating point, for example in the area 13 between the working points A4 and A5 of the high current flow of the characteristic curve 10, results for precisely this user. In particular, the method also provides for a switch-on curve of the high-voltage source to be recorded, the switch-on curve ending at an operating point.

By acquiring a switch-on curve, it is possible to determine the state in which the electrohydrodynamic atomizer should initially be operated, a switch-on curve Kl on the

Working point Al shows that a state of the fault is being controlled, which e.g. is brought about by the situation according to FIG. 2d.

By recording the switch-on curves - e.g. Kl to K4 - can e.g. a measure is taken at an early stage, which is assigned to the started working point, before this

Working point is reached. E.g. the high voltage or the pump can be blocked if an operating point A5 'outside the functional range is controlled via the switch-on curve K5.

The turn-on curves K2 to the working point A2, K3 to the working point A3 and K4 to the working point A4 in turn represent possible ones

Operating states.

The situation according to FIG. 2a usually offers a rather low internal resistance in the circuit 28, so that a rather high current will flow, whereby the working point A4 is used.

In the situations according to FIGS. 2b and 2c, the resistances in the circuits 29 and 47 are likely to be higher since the

Internal resistance of both persons 41 and 43 and, if applicable, the conductive base 30 must be taken into account. Comparable objects are provided with the same reference symbols in FIGS. 2b to 2d.

The term “characteristic curve” within the meaning of the invention is also to be understood to mean data collections of characteristic data which can be compared with recorded working points in order to carry out the functional check according to the invention.

Another preferred embodiment of the method, e.g. 2a can provide that the evaluated voltage U and / or the current I over at least one

Correction parameter is corrected. The problem is that due to the given spatial proximity between the hand 22 of the user 21 who operates the atomizer 20 and the

atomized fluid 23 a considerable current flow or

Voltage drop occurs directly between the holding hand 22 and the atomizer 20, without this for

Coating result contributes. About at least one

Correction parameters, for example by means of a calibration operation or a measurement pulse, the influence of the direct current flow and / or the direct voltage drop between the atomizer 20 and the hand 22 of the user 21, which operates the atomizer 20, can be detected. Then, at least one correction parameter, for example a disturbance variable or the like, which is included in the method for function control, can be determined using this. Reference symbol list:

10 Current-voltage characteristic

11 area

12 Fault area

20 atomizers

21 users

22 hand

23 atomized fluid

24 arm

28 closed circuit

29 circuit

30 conductive underground

40 fault

41 first person

42 atomizers

43 second person

44 open circuit

45 underground

46 touch

47 circuit

48 atomization

A0-A5 operating point

A3 'previously recorded operating point

A5 'working point

I current / current flow

K1-K4 switch-on curves

U voltage

Claims

Expectations :

1. Procedure for checking the function of a

electrohydrodynamic atomizer (20), of which

Atomizer (20) starting an electrohydrodynamically atomized fluid (23) onto a body, e.g. a person is applied to coat this body at least in sections, the atomizer (20) comprising 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 by means of the pump unit is conveyed to a nozzle arrangement of the atomizer (20), and the fluid at the nozzle arrangement by means of the action of the

High voltage from the high voltage source is electrohydrodynamically atomized, characterized in that a voltage (ü) and / or a current (i) at the

High-voltage source is evaluated in order to have a current-voltage characteristic (10) or a characteristic field

Detect operating point (A0-A5) of the high voltage source.

2. The method according to claim 1, characterized in that the evaluated voltage (U) and / or the current (I) to the actual voltage value and / or current value of the

High voltage source is proportional reference voltage and / or a reference current

3. The method according to claim 1 or 2, characterized in that the atomizer (20) in the hand (22) of a user (21) is held and a current flow from the high voltage source (20) via the atomized fluid (23) by the hand (22) of the user (21) via hand contact elements on the atomizer (20) back to the high-voltage source and evaluated.

4. The method according to claim 1, 2 or 3, characterized in that a plurality of operating points (A0-A5) on the current-voltage characteristic (10) are defined, wherein the detected actual working point at the high-voltage source with an operating point 8A0 -A5) is compared, or at least in a region lying on the current-voltage characteristic curve between two operating points (A0-A5).

5. The method according to any one of the preceding claims, characterized in that a target working area is defined on the Stro - voltage characteristic (10), in which case the detected actual working point is outside the target working area, a malfunction is signaled.

6. The method according to any one of the preceding claims, characterized in that a regular detection of the

Working point (A0-A5) is carried out, with a detected

Working point (A3) with at least one previously recorded

Working point (A3 ') is compared to change the

Recognizing the working point.

7. The method according to any one of the preceding claims, characterized in that the detected working point (A0-A5) a defined user information and / or device response, e.g.

a connection, which triggers depending on the Position of the working point (A0-A5) on the current-voltage characteristic (10) is held in a memory.

8. The method according to any one of the preceding claims, characterized in that a turn-on curve (K1-K4)

High-voltage source is detected, the switch-on curve (Kl-K4) ending in an operating point (A0-A5).

9. The method according to any one of the preceding claims, characterized in that the evaluated voltage (U) and / or the current (I) via at least one correction parameter such

is corrected that a direct current flow and / or a

direct voltage drop between the atomizer (20) and the hand (22) of the user (21), which operates the atomizer (20), is detectable and can preferably be evaluated as a disturbance variable.

10. High voltage source for performing a method according to one of the preceding claims, characterized in that a proportional to the high voltage output

Low voltage signal can be tapped as a reference voltage.