Metering valve

Abstract

A metering valve comprises a closable media passage leading from a media supply to a nozzle opening, wherein the medium can be applied to the workpiece in a metered manner through the nozzle opening. The metering valve is provided with a plasma generator by which the workpiece can be acted on by a plasma jet.

Claims

1. A metering valve for liquid medium, the metering valve comprising a closable medium passage leading from a medium supply to a nozzle opening, wherein the medium can be applied to a workpiece in a metered manner through the nozzle opening; the metering valve is provided with a camera by which an image of a surface of the workpiece can be transferred; the metering valve is provided with a plasma generator by which the workpiece can be acted on by a plasma jet; and wherein a detection zone of the camera intersects the plasma jet, whereby an image of the plasma jet incident on the workpiece surface can be captured by the camera and communicated to a processing unit to regulate metering of the medium and to control the plasma jet, wherein an axis of the plasma jet, a trajectory of the metered medium, and an optical axis of the camera extend in parallel with one another, wherein the axis of the plasma jet, the trajectory of the metered medium, and the optical axis of the camera are arranged in a common plane and communicated to a processing unit to regulate metering of the medium and to control the plasma jet, wherein an axis of the plasma jet, a trajectory of the metered medium, and an optical axis of the camera extend in parallel with one another, wherein the axis of the plasma jet, the trajectory of the metered medium, and the optical axis of the camera are arranged in a common plane.

2. The metering valve in accordance with claim 1, wherein the plasma jet emanates next to the nozzle opening.

3. The metering valve in accordance with claim 1, wherein the plasma generator comprises a piezo transformer and a gas supply.

4. The metering valve in accordance with claim 3, wherein a longitudinal axis of the piezo transformer extends at an oblique angle to the axis of the plasma jet.

5. The metering valve in accordance with claim 1, wherein a gas passage is provided therein whose outlet opening is arranged next to the nozzle opening.

6. The metering valve in accordance with claim 1, wherein the plasma generator and the camera are each configured as modules.

7. The metering valve in accordance with claim 1, wherein the plasma generator has a gas passage in which a pressure regulation unit is provided that is controlled by the processing unit provided at the metering valve.

Description

(1) The present invention will be described in the following purely by way of example with reference to an advantageous embodiment and to the enclosed drawings.

(2) There are shown:

(3) FIG. 1 a perspective view of a metering valve;

(4) FIG. 2 a plan view of the end face of the metering valve of FIG. 1;

(5) FIG. 3 a partly sectional view of the representation of FIG. 2;

(6) FIG. 4 a partly sectional view through the plasma generator of the metering valve of FIG. 1; and

(7) FIG. 5 a schematic plan of the metering valve of FIG. 1.

(8) The metering valve 10 shown perspectively in FIG. 1 is of a modular design and comprises a valve module 12, a plasma generator module 14, and a camera module 16 that are arranged next to one another and are connected to one another. A pressure regulation valve 18 and a processing unit 20 for controlling the metering process are additionally located at the metering valve 10.

(9) The valve module 12 has a closable media passage leading from a media supply not shown, to a nozzle opening 31, a generally known valve drive 22, and a replaceable valve core 24. The valve drive and the vale core here correspond to the metering valves typically used for metering applications and known from the prior art.

(10) The plasma generator module 14 is fastened directly to a main surface of the generally parallelepiped-shaped valve module 12, is likewise parallelepiped-shaped, and has a gas connector 26 and a gas passage 28 that extends through the plasma generator module 14 and has an outlet opening 30 that is directed perpendicularly downward in the position of the metering valve 10 shown and is arranged directly next to the nozzle opening 31. The gas conducted through the gas passage 28 and ionized before discharge is applied as a plasma jet P perpendicular to a workpiece surface W.

(11) As the cross-section through the plasma generator module 14 of FIG. 4 illustrates, it has a piezo transformer 32 that is formed as an elongate bar, that is arranged diagonally in the generally parallelepiped-shaped plasma generator module 14, and that generates a high voltage at its lower end (its right end in FIG. 4). FIG. 4 here illustrates that the axis of the plasma jet P extends at an oblique angle to the longitudinal axis L of the piezo transformer 32, and indeed at an obtuse angle of approximately 120° in the embodiment shown. Gas that flows through the gas passage 28 is supplied from a pressure container 34 (FIG. 5) filled with helium or nitrogen, for example, via a mechanical pressure regulator 36 to the gas connector 26. Shortly before the discharge through the outlet opening 30 of the gas passage 28, the gas is ionized by the high voltage generated by the piezo transformer 32 and is subsequently discharged as cold plasma P. The pressure of the process gas is preferably set to a value sensible for the application via the mechanical pressure regulator 36. A fine setting and a measurement or monitoring of the pressure subsequently takes place by a pressure regulator 18 regulated by the processing unit 20. A diaphragm 38 via which the volume flow of the gas can be set is provided in the gas passage 28 after the pressure regulator in the direction of flow.

(12) FIG. 1 further illustrates that the likewise approximately parallelepiped-shaped camera module 16 is arranged and fastened at a main surface of the plasma generator module 14. A camera 42 by which an image of the workpiece surface W can be transferred is installed in this camera module 16 and is provided with a USB connection 40 (FIG. 5). FIGS. 2 and 3 illustrate the detection zone E of the camera 42 directed perpendicularly downwardly and it can easily be recognized that this image detection zone intersects the plasma jet P so that an image of the plasma jet P incident on the workpiece surface W can be captured by the camera 42.

(13) It furthermore becomes clear from FIG. 2 that the optical axis O of the camera 42, the axis of the plasm jet P, and the trajectory M of the metered medium extend in parallel with one another. They are furthermore also arranged on a straight line disposed in the plane of the drawing of FIG. 2.

(14) The processing unit 20 that is provided with a microcontroller controls both the plasma generator 14 and the pressure regulator 18. The processing unit 20 is furthermore connected to a higher ranking processing unit to which the camera 42 and the control electronics of the valve module 22 are also connected. The process monitoring and the synchronization and control of the plasma generation as well as the metering and the robot movement take place via this higher ranking processing unit.

(15) In accordance with a further embodiment, not shown, the valve module 22 and the plasma generator module 14 can also be provided with a nozzle passage extension. The installation height of the camera 42 can then be adapted accordingly.