Spray nozzle device and coating method

Abstract

A spray nozzle apparatus for spraying a spray jet which contains a coating material in one spray direction S for coating of a surface which is located in the spray direction S opposite the spray nozzle apparatus transversely to the spray direction S with a spray nozzle for spraying the spray jet from a spray nozzle outlet of the spray nozzle and at least one control nozzle with a control nozzle outlet which is aligned or can be aligned to the spray jet transversely to the spray direction S for acting on the spray jet and deflecting it by means of a control flow which is emerging from the control nozzle outlet, characterized in that there is one control apparatus for control of the control flow with a control signal.

Claims

1. A spray nozzle apparatus for coating a surface that is located in a spray direction S opposite the spray nozzle apparatus transversely to the spray direction S, the apparatus comprising: a spray nozzle that is statically fixed relative to movement of the surface to be coated, the spray nozzle comprising a spray nozzle outlet, the spray nozzle being configured to spray a spray jet containing a coating material in the spray direction S from the spray nozzle outlet, the spray nozzle being unable to rotate at least in one direction transversely to relative movement between the surface to be coated and the spray nozzle, at least two control nozzles, each of the control nozzles comprising a control nozzle outlet aligned to the spray jet transversely to the spray direction S, each of the control nozzles being configured to produce a control flow from the control nozzle outlet to act on and deflect the spray jet, and a control apparatus from which separately controlled control signals are provided to control the control flows, wherein a frequency of the control signals is between >0 and 500 Hz.

2. The spray nozzle apparatus as claimed in claim 1, wherein the control apparatus is software-supported to control the control flows from the control nozzle outlets, the control flows being gaseous control flows.

3. The spray nozzle apparatus as claimed in claim 1, wherein each of the control signals has a phase shift with destructive interference.

4. The spray nozzle apparatus as claimed in claim 1, wherein the control nozzles have mechanical and/or fluid dynamic components that are switchable by the control signals to influence flow properties of the control flows.

5. The spray nozzle apparatus as claimed in claim 1, wherein the spray nozzle further comprises an ultrasonic atomizer and/or a Venturi nozzle.

6. The spray nozzle apparatus as claimed in claim 1, wherein the control flows are aligned at an angle W from 30 to 150 to the spray direction S to the spray jet.

7. The spray nozzle apparatus as claimed in claim 1, wherein the control apparatus is further configured to tilt and/or rotate the control nozzles relative to the spray nozzle to adjust alignment of the respective control flows to the spray jet.

8. A system for coating of a surface of a substrate with a single spray nozzle apparatus, the surface being located in a spray direction S opposite the spray nozzle apparatus transversely to the spray direction S, the system having: a spray nozzle apparatus configured to coat the surface of the substrate, the surface being located in a spray direction S opposite the spray nozzle apparatus transversely to the spray direction S, the apparatus comprising: a spray nozzle that is statically fixed relative to movement of the surface to be coated, the spray nozzle comprising a spray nozzle outlet, the spray nozzle being configured to spray a spray jet containing a coating material in the spray direction S from the spray nozzle outlet, the spray nozzle being unable to rotate at least in one direction transversely to relative movement between the surface to be coated and the spray nozzle, at least two control nozzles, each of the control nozzles comprising a control nozzle outlet aligned to the spray jet transversely to the spray direction S, each of the control nozzles being configured to produce a control flow from the control nozzle outlet to act on and deflect the spray jet, means for executing relative motion between the substrate and the spray nozzle apparatus transversely to the spray direction S, and a control apparatus from which separately controlled control signals are provided to control the control flows, wherein a frequency of the control signals is between >0 and 500 Hz.

9. The system as claimed in claim 8, wherein the relative motion takes place by translational movement of the substrate.

10. The system as claimed in claim 8, wherein the control apparatus is configured to tilt and/or rotate the control nozzles relative to the spray nozzle to adjust alignment of the respective control flows to the spray jet.

11. A system for coating a surface, comprising: a spray nozzle that is statically fixed relative to movement of the surface to be coated, the spray nozzle having a spray nozzle outlet for creating a spray jet of a coating material, said spray jet directed in a spray direction S toward the surface, said surface being oriented transversely to said spray direction S, the spray nozzle being unable to rotate at least in one direction transversely to relative movement between the surface to be coated and the spray nozzle; at least two control nozzles each having a control nozzle outlet, said control nozzles disposed relative to said spray nozzle such that said control nozzle outlets are alignable transversely to said spray direction S; means for creating a control flow from each of said control nozzle outlets to act on and deflect the spray jet; and a control apparatus generating a control signal for each of said control nozzle outlets for controlling the control flow from each of said control nozzle outlets, wherein each control signal has a frequency between >0 and 500 Hz.

12. The system as claimed in claim 11, wherein the control apparatus is configured to tilt and/or rotate the control nozzles relative to the spray nozzle to adjust alignment of the control flow from each of said control nozzle outlets to the spray jet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic of one embodiment of a spray nozzle apparatus according to the invention and

(2) FIG. 2 shows a schematic of the operation of the spray nozzle apparatus,

(3) FIG. 3 shows a schematic of a system according to the invention from above, and

(4) FIG. 4 shows a schematic of a system according to the invention in a side view.

(5) In the figures, advantages and features of the invention are labeled with reference numbers which identify them according to embodiments of the invention, components and features with the same function and/or a function with the same action being labeled with identical reference numbers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) The spray nozzle apparatus 15 is comprised of a spray nozzle 1, with one spray nozzle outlet 2 and at least two control nozzles 3 and 4, with corresponding control nozzle outlets 5 and 6.

(7) The spray nozzle 1 is supplied with a coating material which is atomized. The atomization takes place preferably with an ultrasonic atomizer or by means of a Venturi nozzle within the spray nozzle 1. The spray nozzle 1 at the spray nozzle outlet 2 produces a spray jet 14 which is directed in one spray direction S, as a spray mist whose form can be preset by a correspondingly engineered spray nozzle outlet 2.

(8) The control nozzles 3, 4 each produce one gaseous control flow 12, 13 which emerges at the control nozzle outlets 5 and 6. The control flows 12, 13 are aligned or can be aligned to the spray jet 14.

(9) The pressure, the atomization rate, the average velocity, the temperature, and the electric charge of the atomized coating material and/or of the gaseous control flows 12, 13 can be set and changed by the control apparatus 11 that is controlled by software. It is also contemplated to make the alignment of the control flows 12, 13 to the spray jet 14 adjustable, by means for tilting and/or rotating the control nozzles 3, 4 relative to the spray nozzle 1.

(10) One main concept of the invention comprises the exact time monitoring of the average velocity and/or of the pressure of the control flows 12, 13 which are emerging from the control nozzles 3, 4 via the control nozzle outlets 5, 6. Control signals 9, 10 of one control apparatus of the spray nozzle apparatus 15 switch corresponding mechanical and/or fluid dynamic components within the control nozzles 3, 4. The mechanical and/or fluid dynamic components, which are not described in detail, can be control valves, proportional valves, switches, atomizers and/or throttles. Common to all is that there is one physical property which can be varied or controlled promptly in time and which has a direct effect on the average velocity and/or the pressure of the control flows 12, 13, and thus, an effect on the triggering or deflection of the atomized coating gas 14.

(11) According to the invention, primarily complicated, empirically and/or theoretically determined or computed functions, less preferably sinusoidal signals and/or triangular signals, optionally also (especially combined with the aforementioned signals) rectangular signals are used to trigger, i.e., control, the control nozzles 5, 6, such as by means of one of the oscilloscopes 7, 8 which are assigned to one of the control nozzles at a time. Preferably, the two signals 9 and 10 have a corresponding phase difference or phase shift to one another in order to ensure a time offset of the control flows 12 and 13. In this respect, it is preferable if the phase shift of the two control signals 9, 10 has destructive interference. An extremely homogeneous coating is possible in this way.

(12) FIG. 2 shows a time line along which three different states of a spray nozzle apparatus 15 according to the invention are represented. At a first instant t1, a control flow 12 of the control nozzle 4 is used in order to deflect the spray jet 14 from the spray direction S to the left. The instant t1 shows the state in which the control signal 9 for triggering the control nozzle 4 has a maximum and the control signal 10 for triggering the control nozzle 3 has a minimum. The triggering states when a sinusoidal signal is injected would be for example a maximum value and a minimum value of the sinusoidal signal.

(13) At a second instant t2, the control signals 9 and 10 are equal, in particular, equal to 0 so that on the two control nozzles 5, 6 no control flows 12, 13 or control flows 12, 13 which mutually cancel are acting on the spray jet 14. The spray jet 14 can therefore move unhindered normally to the surface which is to be coated, therefore in the spray direction S.

(14) At a third instant t3, the situation which was reversed at instant t1 occurs, in which the control nozzle 3 causes the deflection of the spray jet 14 to the right.

(15) According to the invention, a signal which is continuous over the entire definition range is used to continuously change the flow properties, especially the average velocity and/or volumetric flow, of the control flows 12 and 13. Accordingly, the three instants which are shown in FIG. 2 represent only extracts from a number of instants which is infinite in the boundary case, and for which the control signals 9 and 10 cause a continuous control of the control flows 12 and 13.

(16) In other words, the spray jet 14 is deflected alternately to the left and right by the arrangement and alignment of the control flows 12, 13 which is opposite relative to the spray direction S as a mirror axis so that a homogeneous distribution of the coating material on the surface of the substrate 17 results.

(17) Softer control signals which produce a more homogeneous layer, and thus, which are superior to the embodiments of the prior art are introduced by the embodiment. The control signals are therefore described, from a mathematical standpoint, by continuous, preferably even continuously differentiable, more preferably continuous, continuously differentiable functions.

(18) The substrate 17 which is to be coated during the triggering of the control nozzles 3 and 4 is passed under the spray jet 14 in one direction R so that the substrate 17 can be coated along the entire substrate 17. Moreover, the invention encompasses a larger section A of width B of the substrate 17 so that with a single spray apparatus which is static relative to the system, a relatively large area can be homogeneously coated. In particular, the section A corresponds to the width B.

(19) A distance H between the spray nozzle apparatus 15 and an area of the substrate 17 to be coated in the normal direction to the area, i.e., in the spray direction S, can be controlled. The distance H is smaller than the section A.

(20) According to FIG. 3, there are several sensors 18 in the direction R upstream and/or downstream of the spray nozzle apparatus 15. The sensors 18 are arranged preferably flush with one another normal, i.e., perpendicular, to the direction R of movement of the substrate 17, in the spray direction at a uniform height between the spray apparatus 15 and the area which is to be coated.

(21) The sensors 18 are designed to measure physical and/or chemical properties of the area to be coated upstream and/or downstream of the spray nozzle apparatus 15.

(22) The sensors 18 which are located upstream of the spray nozzle apparatus 15 determine the state of the surface of area parts prior to coating.

(23) After coating, the sensors which are located downstream of the spray nozzle apparatus 15 determine the state of the area or area parts which were to be coated.

REFERENCE NUMBER LIST

(24) 1 spray nozzle 2 spray nozzle outlet 3 control nozzle 4 control nozzle 5 control nozzle outlet 6 control nozzle outlet 7 oscilloscope 8 oscilloscope 9 control signal 10 control signal 11 control apparatus 12 control flow 13 control flow 14 spray jet 15 spray nozzle apparatus 17 substrate 18 sensors H distance between spray nozzle and substrate R direction of motion opening angle opening angle A section B width