DEVICE FOR PROCESSING A WORKPIECE

Abstract

A device for processing a workpiece includes at least one plunger pump, which is drivable by means an electric motor and which generates a highly pressurized volume flow, which volume flow can be interrupted in controlled fashion and emerges from at least one connected consumer. The volume flow is conveyed at substantially constant high pressure via a pressure line to the consumer. The electric motor is a reluctance motor, which is controllable by a connected frequency converter. A pressure sensor is connected to the pressure line, which pressure sensor is connected to a controller.

Claims

1-5. (canceled)

6. A device for processing a workpiece, the device comprising: an electric motor; at least one plunger pump coupled to the electric motor so that the at least one plunger pump generates a volume flow under a high pressure that can be interrupted in a controlled manner and that exits from at least one connected consumer; and a pressure line coupled to the at least one plunger pump, wherein the volume flow is delivered to the consumer via the pressure line under substantially uniform high pressure, wherein the electric motor is a reluctance motor, which is controllable via a connected frequency converter, and wherein a pressure sensor, which is connected to a regulator, is connected to the pressure line.

7. The device of claim 6, wherein the frequency converter includes a DC intermediate circuit, which is connected to a brake resistance.

8. The device of claim 6, further comprising: a damper arranged in the pressure line for damping a fluid pressure, which increases after a shutdown of the at least one plunger pump.

9. The device of claim 6, further comprising: a capacitive energy accumulator operationally connected to the reluctance motor via the frequency converter to store braking energy.

10. A method for operating a device for processing a workpiece, wherein the device comprises an electric motor, at least one plunger pump coupled to the electric motor so that the at least one plunger pump generates a volume flow under a high pressure that can be interrupted in a controlled manner and that exits from at least one connected consumer, and a pressure line coupled to the at least one plunger pump, wherein the volume flow is delivered to the consumer via the pressure line under substantially uniform high pressure, wherein the electric motor is a reluctance motor, which is controllable via a connected frequency converter, and wherein a pressure sensor, which is connected to a regulator, is connected to the pressure line, the method comprising: comparing the delivered volume flow is compared to a volume flow taken by the consumer based on a predetermined speed of the plunger pump, wherein in the event of a deviation of the delivered volume flow from a target value, a signal is provided or the reluctance motor and thus the plunger pump are shut down.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURE

[0024] One exemplary embodiment of the invention is described hereafter on the basis of the appended drawing.

[0025] The single FIGURE shows the conceptual structure of the device according to the invention in a block diagram.

DETAILED DESCRIPTION

[0026] A device for processing a workpiece is depicted in the FIGURE, having a plunger pump 1, which comprises three plungers 18 in the example, which are mounted on a crankshaft 8, preferably offset by 120 in relation to one another, and are drivable in an oscillating manner by means of an electric motor connected to the crankshaft 8.

[0027] The electric motor is designed as a reluctance motor 7 according to the invention and is connected to a frequency converter 2 comprising a rectifier 3, a DC intermediate circuit 4, and an inverter 5.

[0028] A brake resistance 6 is connected to the DC intermediate circuit 4 of the frequency converter 2, which effectuates a rapid reduction of the speed of the crankshaft 8 upon shutdown of the reluctance motor 7.

[0029] On the suction side, the plungers 18 are connected to a fluid accumulator 20, while the fluid, which is under a high pressure after a work cycle of the plungers 18, is supplied via a pressure line 19 in the example to two consumers 12 in the form of a nozzle, wherein a check valve 17 is arranged between the pressure line 19 and the respective plunger 18.

[0030] The pressure line 19 is closed via shutoff valves 11 to interrupt the volume flow from the consumers 12, wherein the fluid pressure in the pressure line 19 rises immediately.

[0031] This pressure increase is ascertained via a pressure sensor 13 in the pressure line 19, to which a regulator 9 is connected, in which a target value 14 is compared to an actual value 15 recognized via the pressure sensor 13 and as an actuating value 16, the reluctance motor 7 is throttled via the frequency converter 2 in its speed down to a standstill, using the brake resistance 6.

[0032] During this time, the pressure is maintained in the pressure line 19, so that the volume flow is immediately available at operating pressure after opening of the shutoff valves 11.

[0033] Since in principle the throttling of the speed of the reluctance motor 7 occurs delayed by a certain time span after closing of the pressure line 19 via the shutoff valves 11, the pressure rises further in the pressure line 19.

[0034] To prevent components subjected thereto from being damaged, a damper 10 is integrated upstream from the shutoff valves 11 in the pressure line 19, by means of which the available higher pressure is absorbed by compression of the fluid.

[0035] Although the invention has been illustrated and described in detail by way of preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived from these by the person skilled in the art without leaving the scope of the invention. It is therefore clear that there is a plurality of possible variations. It is also clear that embodiments stated by way of example are only really examples that are not to be seen as limiting the scope, application possibilities or configuration of the invention in any way. In fact, the preceding description and the description of the FIGURES enable the person skilled in the art to implement the exemplary embodiments in concrete manner, wherein, with the knowledge of the disclosed inventive concept, the person skilled in the art is able to undertake various changes, for example, with regard to the functioning or arrangement of individual elements stated in an exemplary embodiment without leaving the scope of the invention, which is defined by the claims and their legal equivalents, such as further explanations in the description.

LIST OF REFERENCE NUMERALS

[0036] 1 plunger pump [0037] 2 frequency converter [0038] 3 rectifier [0039] 4 DC intermediate circuit [0040] 5 inverter [0041] 6 brake resistance [0042] 7 reluctance motor [0043] 8 crankshaft [0044] 9 regulator [0045] 10 damper [0046] 11 shutoff valve [0047] 12 consumer [0048] 13 pressure sensor [0049] 14 target value [0050] 15 actual value [0051] 16 actuating value [0052] 17 check valve [0053] 18 plunger [0054] 19 pressure line [0055] 20 fluid accumulator