APPARATUS FOR THE EROSIVE MACHINING AND/OR CLEANING OF A MATERIAL OR A WORKPIECE SURFACE BY MEANS OF AT LEAST ONE HIGH-PRESSURE FLUID JET, AND METHOD FOR OPERATING SUCH AN APPARATUS

Abstract

The invention relates to a device for the erosive processing and/or the cleaning of a material or of a material surface by means of at least one high-pressure fluid jet, comprising a nozzle (1) for outputting a high-pressure fluid jet and an apparatus (2) arranged upstream of the nozzle (1) for producing a pulsed high-pressure fluid jet, wherein the apparatus (2) comprises at least one valve (3). According to the invention, the valve (3) is designed as a servo valve and has an axially movable valve piston (4) for connecting a valve feed (5) to a valve outlet (6) such that the flow through the valve (3) can be specified by means of the axial position of the valve piston (4). The invention further relates to a method for operating a device according to the invention.

Claims

1. An apparatus for the erosive machining and/or cleaning of a material or a workpiece surface by means of at least one high-pressure fluid jet, the apparatus comprising a nozzle (1) for outputting a high-pressure fluid jet, and a device (2), connected upstream of the nozzle (1), for generating a pulsed high-pressure fluid jet, wherein the device (2) comprises at least one valve (3) that is configured as a servo valve and that has an axially displaceable valve piston (4) for connecting a valve inlet (5) to a valve outlet (6) such that a flow rate through the valve (3) is defined via an axial position of the valve piston (4).

2. The apparatus as claimed in claim 1, characterized in that the valve piston (4) bounds a control chamber (8) that is configured to be relieved via a pilot valve (7) and that is hydraulically connected to the valve inlet (5) such that, with the pilot valve (7) closed, the same hydraulic pressure prevails in the control chamber (8) as in the valve inlet (5).

3. The apparatus as claimed in claim 2, characterized in that the valve piston (4) has at least one duct (9) for hydraulically connecting the control chamber (8) to the valve inlet (5).

4. The apparatus as claimed in claim 1, characterized in that the valve piston (4) is embodied as a stepped piston and has a first end face (4.1), facing the valve inlet (5), which is smaller than a second end face (4.2), facing away from the valve inlet (5), for bounding the control chamber (8).

5. The apparatus as claimed in claim 2, characterized in that the pilot valve (7) is electromagnetically or piezoelectrically actuable.

6. The apparatus as claimed in claim 1, characterized in that the device (2) comprises a fluid store (10) for supplying the valve (3) with fluid.

7. The apparatus as claimed in claim 1, characterized in that, in order to deliver the fluid at a high pressure, the apparatus comprises a high-pressure pump (11) which is a constituent part of the device (2) or is connected upstream of the device (2).

8. A method for operating an apparatus as claimed in claim 1, characterized in that, in order to generate a pulsed high-pressure fluid jet, the valve (3) of the device (2) is actuated in a clocked manner.

9. A method for operating an apparatus as claimed in claim 1, characterized in that, in order to generate a pulsed high-pressure fluid jet, the valve (3) of the device (2) is actuated in a clocked manner with a clock frequency of 40 to 200 Hz.

10. The apparatus as claimed in claim 2, characterized in that the valve piston (4) has at least one duct (9) for hydraulically connecting the control chamber (8) to the valve inlet (5), wherein a total effective flow area of the one duct (9) or of the plurality of ducts (9) is less than an effective flow area that is able to be opened up by the pilot valve (7).

11. The apparatus as claimed in claim 1, characterized in that, in order to deliver the fluid at a high pressure, the apparatus comprises a high-pressure pump (11) which is a constituent part of the device (2) or is connected upstream of the device (2), wherein the high-pressure pump (11) is configured to be driven via an electric motor (12).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] A preferred embodiment of the invention is described in more detail in the following text with reference to the appended drawings, in which:

[0020] FIG. 1 shows a schematic illustration of an apparatus according to the invention according to a preferred embodiment of the invention, and

[0021] FIG. 2 shows a schematic longitudinal section through a valve of the apparatus in FIG. 1.

DETAILED DESCRIPTION

[0022] The illustration in FIG. 1 is limited to the essential components of an apparatus according to the invention. These are a nozzle 1 for outputting a high-pressure fluid jet and a device 2 for generating a pulsed high-pressure fluid jet. To this end, the device 2 comprises a valve 3, which is embodied as a servo valve and is described in more detail in the following text in conjunction with FIG. 2. Connected upstream of the valve 3 is a fluid store 10, to which fluid under high pressure, in the present case water, is able to be fed via a high-pressure pump 11. The fluid store 10 and the high-pressure pump 11 are, like the valve 3, constituent parts of the device 2. The latter furthermore comprises an electric motor 12 for driving the high-pressure pump 11. The high-pressure pump 11 can be driven continuously via the electric motor 12, such that fluid is fed continuously to the fluid store 10.

[0023] FIG. 2 illustrates a preferred configuration of the valve 3 of the device 2. The valve 3 is embodied as a servo valve and comprises a valve piston 4, displaceable back and forth in an axial direction, for connecting a valve inlet 5 to a valve outlet 6. The direction of movement of the valve piston 4 is indicated by the arrow 13. The valve outlet 6 is formed in the present case by two mutually opposite, radially extending bores, while the valve inlet 5 is arranged axially. Depending on the axial position of the valve piston 4, the bores that serve as the valve outlet 6 are accordingly closed or at least partially opened up, such that the flow rate through the valve 3 is able to be determined thereby.

[0024] The axial position of the valve piston is hydraulically controllable. To this end, the valve piston 4 has a first end face 4.1, which faces the valve inlet 5 and is subjected to inlet pressure. A second end face 4.2, facing away from the valve inlet 5, of the valve piston 4 bounds a control chamber 8 which is able to be relieved via a pilot valve 7. As long as the pilot valve 7 is closed, inlet pressure likewise prevails in the control chamber 8, since a duct 9, which hydraulically connects the control chamber 8 to the valve inlet 5, is formed in the valve piston 4. The diameter D.sub.1 of the duct 9 is selected to be smaller than the diameter D.sub.2 of an outflow opening 16 that is closable via a valve closing element 14 of the pilot valve 7, such that, with the pilot valve 7 open, the pressure in the control chamber 8 drops reliably and quickly. In a supporting manner, the area ratio of the two end faces 4.1 and 4.2 of the valve piston 4 is selected such that the hydraulic pressure force that brings about the axial displacement of the valve piston 4 acts in a reinforced manner. To this end, the valve piston 4 is embodied in a stepped manner, wherein the end face 4.1 having the diameter D.sub.3 is much smaller than the end face 4.2 having the diameter D.sub.4.

[0025] The pilot valve 7 is actuated electromagnetically in the present case. To this end, the pilot valve 7 comprises an electromagnet 15, via the magnet force of which it is possible to act on an armature (not illustrated), capable of reciprocating movement, coupled to the valve closing element 14. If the armature lifts, the valve closing element 14 is capable of opening. Via the outflow opening 16, fluid then flows out of the control chamber 8, resulting in a pressure drop in the control chamber 8. The higher inlet pressure present at the end face 4.1 thus results in an axial displacement of the valve piston 4 in the direction of the pilot valve 7, such that a greater flow area of the valve outlet 6 is opened up and the flow rate through the valve 3 is increased. In this way, a fluid pulse or a pulsed high-pressure fluid jet is generated.

[0026] The invention is not limited to the exemplary embodiment illustrated. Rather, modifications are possible which relate in particular to the specific configuration of the valve 3. Furthermore, the working pressure can vary. The latter depends in particular on the working medium, which is preferably water. However, oil/water emulsions can also be used as the working medium.