DEVICE AND METHOD FOR CUTTING A GOOD TO BE CUT BY MEANS OF A FLUID

Abstract

A device for cutting a cuttable material with the aid of a fluid, in particular for water-jet cutting, may include a pressure-generating unit and an outlet nozzle that is fluidically connected to the pressure-generating unit via a fluid line. The pressure-generating unit may pressurize the fluid in the fluid line. The device may further comprise a pulsation damper for damping pressure fluctuations in the fluid line. The device may also include at least one switching valve such that, depending on a switching position of the switching valve, the pulsation damper is couplable to the fluid line and uncouplable from the fluid line.

Claims

1.-15. (canceled)

16. A device for cutting a cuttable material with the aid of a fluid, the device comprising: an outlet nozzle; a pressure-generating unit, wherein the outlet nozzle is fluidically connected to the pressure-generating unit via a fluid line, wherein the pressure-generating unit pressurizes the fluid in the fluid line; a switching valve; and a pulsation damper for damping pressure fluctuations from the fluid line, wherein depending on a switching position of the switching valve the pulsation damper is couplable to the fluid line and uncouplable from the fluid line.

17. The device of claim 16 wherein the pressure-generating unit has a controllable output pressure that is operable at least in a first operating mode at a first working pressure and in a second operating mode at a second working pressure, wherein the first working pressure is larger than the second working pressure.

18. The device of claim 16 wherein the device is switchable between a first operating mode for cutting the cuttable material, wherein in the first operating mode the pressure-generating unit provides a first working pressure and the pulsation damper is coupled to the fluid line by the switching valve; and a second operating mode for an initial perforation of the cuttable material, wherein in the second operating mode the pressure-generating unit provides a second working pressure and the pulsation damper is uncoupled from the fluid line by way of the switching valve, wherein the first working pressure is larger than the second working pressure.

19. The device of claim 16 wherein the pressure-generating unit comprises a pressure booster and/or a hydraulically-driven high-pressure pump, an electromechanically-driven high-pressure pump, or a high-pressure pump with a crank drive.

20. The device of claim 16 further comprising a switchable expansion valve, wherein an input side of the switchable expansion valve is fluidically connected to the fluid line and an output side of the switchable expansion valve is at ambient pressure.

21. The device of claim 16 further comprising a mixing chamber for admixing abrasive material with the fluid, wherein the mixing chamber is disposed downstream of the outlet nozzle along a main flow direction of the fluid, wherein the mixing chamber is connected to a reservoir for abrasive material.

22. The device of claim 16 wherein the pulsation damper comprises a closed pressure accumulation chamber that includes only a single access opening, where the single access opening is connected to the fluid line via the switching valve.

23. The device of claim 16 wherein the switching valve is a first switching valve, wherein the pulsation damper comprises a closed pressure accumulation chamber that is connectable in parallel with the fluid line and includes a first access opening and a second access opening, wherein the first access opening is couplable via the first switching valve to the fluid line and uncouplable from the fluid line, wherein the second access opening is couplable via a second switching valve to the fluid line and uncouplable from the fluid line.

24. The device of claim 16 wherein the pulsation damper is a first pulsation damper and the switching valve is a first switching valve, the device further comprising a second pulsation damper that is couplable via a second switching valve to the fluid line and uncouplable from the fluid line.

25. A method for cutting a cuttable material with the aid of a fluid, the method comprising: pressurizing the fluid with a pressure-generating unit; guiding the fluid through a fluid line to an outlet nozzle; impinging the cuttable material with the fluid exiting the outlet nozzle; and coupling/uncoupling a pulsation damper to/from the fluid line by way of a switching valve, wherein in a first operating mode the pulsation damper is coupled to the fluid line by way of the switching valve and in a second operating mode the pulsation damper is uncoupled from the fluid line by way of the switching valve.

26. The method of claim 25 further comprising: generating a first working pressure with the pressure-generating unit in the first operating mode; and generating a second working pressure with the pressure-generating unit in the second operating mode, with the first working pressure being larger than the second working pressure.

27. The method of claim 25 further comprising: closing the switching valve when changing from the first operating mode to the second operating mode; and opening the switching valve when changing from the second operating mode to the first operating mode.

28. The method of claim 27 further comprising controlling the pressure-generating unit such that a pressure in the fluid line drops from a first working pressure to a second working pressure after closing the switching valve when changing from the first operating mode to the second operating mode.

29. The method of claim 28 further comprising controlling the pressure-generating unit such that the pressure in the fluid line rises from the second working pressure to the first working pressure before opening the switching valve when changing from the second operating mode to the first operating mode.

30. The method of claim 27 further comprising controlling the pressure-generating unit such that a pressure in the fluid line rises from a second working pressure to a first working pressure before opening the switching valve when changing from the second operating mode to the first operating mode.

31. The method of claim 25 further comprising at least temporarily opening an expansion valve that is fluidically connected to the fluid line when changing from the first operating mode to the second operating mode.

32. The method of claim 25 wherein the second operating mode is used to initially perforate the cuttable material and the first operating mode is used to subsequently cut the cuttable material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows a diagrammatic view of a device and of a method according to an exemplary first embodiment of the present invention.

[0029] FIG. 2 shows a diagrammatic view of a device and of a method according to an exemplary second embodiment of the present invention.

[0030] FIG. 3 shows a diagrammatic view of a device and of a method according to an exemplary third embodiment of the present invention.

EMBODIMENTS OF THE INVENTION

[0031] In the various figures, the same parts are always provided with the same designations, and are therefore in each case also generally only referred to or mentioned once.

[0032] FIG. 1 shows a diagrammatic view of a device 1 and of a method for cutting a cuttable material 2 with the aid of a fluid according to an exemplary first embodiment of the present invention.

[0033] The device 1 comprises a pressure-generating unit 3 with which water is pressurized. The pressurized water is guided to an outlet nozzle 5 by means of a fluid line 4. In the outlet nozzle 5, the water is highly accelerated due to the large pressure difference between the pressure in the interior of the fluid line 4 and the ambient pressure, and forms a water jet 6. Immediately downstream of the outlet nozzle 5, there is also formed a mixing chamber 7 in which the water is mixed with an abrasive material 9, here in the form of a fine-grained quartz sand. For this purpose, the mixing chamber 7 is connected to a reservoir 8 in which the abrasive material 9 is held. As a result of the venturi effect in the region of the outlet nozzle 5, the abrasive material 9 is automatically drawn into the water jet 6 due to negative pressure. The water jet 6, mixed with abrasive material 9, then strikes the cuttable material 2 that is to be cut. In the present example, the cuttable material 2 comprises a glass.

[0034] An advantage of water-jet cutting is that the water jet 6 itself can make, in the cuttable material 2, its initial bore from which the cuttable material 2 is cut. The making of this initial opening is also referred to as piercing of the cuttable material 2. When cutting glass, however, the problem arises that the glass shatters during the piercing of the glass at full working pressure. A lower working pressure must therefore be used when piercing the glass than when cutting the glass.

[0035] For this purpose, the device 1 is formed such that, and is controlled by control electronics 10 such that, the device 1 is optionally operated in a first operating mode, which is intended for the cutting of the cuttable material 2, and in a second operating mode, which is intended for the piercing of the cuttable material 2. In the first operating mode, the pressure-generating unit 3 is regulated such that a high, first working pressure between 3,000 and 4,000 bar is generated in the fluid line 4, while in the second operating mode, the pressure-generating unit 3 is regulated such that a lower, second working pressure between 600 and 800 bar is generated in the fluid line 4.

[0036] Downstream of the outlet nozzle 5, the device 1 comprises has in particular a cutting valve. The water jet 6 exits through the open cutting valve, while the water jet 6 is interrupted when closing the cutting valve. In this way, a safety shutdown can take place, for example.

[0037] In the present example, the pressure-generating unit comprises a hydraulic unit 11 which drives a dual-acting pressure booster 12. The dual-acting pressure booster 12 comprises, in a known way, a piston 13 which runs in oscillating operation, and to convert a pressure generated in the water by a forepump (not shown) to the first or second working pressure, depending on the operating mode, by means of check valves 14.

[0038] The oscillating operation of the piston 13 gives rise to unwanted pressure pulsations in the fluid line 4. For damping these pressure pulsations, the device 1 comprises a pulsation damper 15 (also referred to as a buffer volume). For this purpose, the pulsation damper 15 comprises a pressure accumulation chamber.

[0039] In the device 1 according to the invention, the pulsation damper 15 is connected to the fluid line 4 via a switching valve 16. Therefore, depending on the position of the switching valve 16, the pulsation damper 15 is coupled to the fluid line 4 (switching valve 16 is open) or uncoupled from the fluid line 4 (switching valve 16 is closed). The switching valve 16 preferably comprises an electromotively actuated valve, an electromagnetically actuated valve, a pneumatically actuated valve, or a hydraulically actuated valve, which is switched by the control electronics 10 during the changeover between the first and second operating mode. The pulsation damper 15 comprises only a single access opening 17, via which the interior of the pulsation damper 15 is fluidically connected to the fluid line 5 via the switching valve 16 (in the case of an open switching valve 16 only).

[0040] If the cuttable material 2 is cut, the device 1 is operated in the first operating mode, and in this case, the pressure-generating unit 3 provides the first working pressure in the fluid line 4. Furthermore, the switching valve 16 is open, and so the pressure pulsations in the fluid line 4 are damped by the pulsation damper 15. Thus, the first working pressure also prevails on average in the pulsation damper 15. If a new cut is then to be made at a new position on the cuttable material 2, for the purpose of applying the water jet 6, the cuttable material 2 must firstly be pierced at this new position. The device 1 must therefore change over from the first operating mode to the second operating mode such that the first working pressure is reduced to the second working pressure and the cuttable material 2 is not destroyed during the piercing operation.

[0041] When switching from the first operating mode to the second operating mode, firstly the switching valve 16 is closed by way of the control electronics 10. The first working pressure is consequently stored in the pulsation damper 15. Afterwards, the pressure-generating unit 3 is brought down in a controlled or regulated manner by the control electronics 10 such that an expansion takes place via the cutting valve and, in the fluid line 4, the first working pressure is no longer provided, but instead the lower, second working pressure is provided. Due to the uncoupling of the pulsation damper 15 beforehand, the pressure of the fluid line 4 drops to the second working pressure relatively quickly, since it is not necessary to also wait for a drop in the pressure in the pulsation damper 15 or the pressure in the pulsation damper 15 firstly counteracts the drop in pressure and the volume of the fluid line 4 is relatively small in comparison with the volume of the pulsation damper 15. In the exemplary device 1, the changeover from the first operating state to the second operating state consequently lasts less than one second. During the second operating mode, the cuttable material 2 can then be pierced. However, in this second operating mode, there is no pulsation damper 15 available for damping pressure fluctuations. It has, however, been found that this situation is not critical for the piercing operation.

[0042] In case an even quicker changeover from the first operating state to the second operating state is desired, the emergency valve (not shown), which acts as an expansion valve and is provided in any high-pressure circuit anyway, can optionally be briefly opened by way of the control electronics 10 (only after the switching valve 16 has been closed), in order to accelerate the drop in pressure in the fluid line 4.

[0043] If the piercing operation has then been carried out and the cuttable material 2 is to be cut starting from the initial opening made during the piercing operation, there is a changeover from the second operating mode back to the first operating mode. Here, firstly the pressure-generating unit 3 is controlled or regulated by the control electronics 10 such that the pressure in the fluid line 4 increases from the second working pressure to the first working pressure. Subsequently the switching valve 16 is opened. This switching operation takes place significantly more quickly than in the case of the prior art, since the increased first working pressure already prevails in the pulsation damper 15 and does not need to be firstly built up anew by the pressure-generating unit 3. The cuttable material 2 can then be cut, and pressure fluctuations in the fluid line 4 are damped by the pulsation damper 15 in the usual manner.

[0044] In the case of the above-mentioned switching of the switching valve 16, the switching valve 16 is always only switched if nearly the first working pressure prevails on both sides of the switching valve 16. Advantageously, the switching valve 16 is consequently subject to only relatively low wear. Furthermore, the pulsation damper 15 is excluded from large pressure fluctuations between the first and second working pressure, since the first working pressure substantially prevails at all times in the pulsation damper 15. The pulsation damper 15 of the present device 1 is accordingly not subjected to any major load cycles and therefore has a significantly longer lifetime.

[0045] The device 1 preferably comprises a pressure measurement device which either measures the pressure inside the fluid line directly via a sensor in the fluid line 4, or determines the pressure in the fluid line 4 indirectly, for example via the position of the hydraulic unit 11. It is also conceivable that the pressure in the pulsation damper 15 is monitored.

[0046] FIG. 2 shows a diagrammatic view of a device 1 and of a method for cutting a cuttable material 2 with the aid of a fluid according to an exemplary second embodiment of the present invention. The second embodiment is almost identical to the first embodiment described in FIG. 1, wherein, in the second embodiment, the only difference from the first embodiment is that the pulsation damper 15 is provided with two access openings 17 and is accordingly couplable to the fluid line 4 via two switching valves, a switching valve 16 and a further switching valve 16. In the first operating state, both switching valves 16, 16 are open, while in the second operating state, both switching valves 16, 16 are closed. If both switching valves 16, 16, are closed the fluid line 4 acts as a bypass with respect to the pulsation damper 15. The only difference with respect to the functioning of the device 1 illustrated in FIG. 1, in the device 1 illustrated in FIG. 2, both switching valves 16, 16 have to be controlled by the control electronics 10 at all times.

[0047] FIG. 3 shows a diagrammatic view of a device 1 and of a method for cutting a cuttable material 2 with the aid of a fluid according to an exemplary third embodiment of the present invention. Again, the third embodiment is almost identical to the first embodiment described in FIG. 1, wherein, in the third embodiment, a difference from the first embodiment is that there additionally provided a separate further pulsation damper 15 which is, via a separate further switching valve 16, couplable to the fluid line 4 or uncouplable from the fluid line 4. The device 1 illustrated in FIG. 3 works exactly as the device 1 illustrated in FIG. 1, wherein, only in the second operating mode, the further pulsation damper 15 is connected to the fluid line 4 by means of the further switching valve 16 as soon as the lower, second working pressure prevails in the fluid line, otherwise (in particular in the first operating mode) the further switching valve 16 is closed. In the further pulsation damper 15, the second working pressure therefore likewise prevails at all times, and thus, on the one hand, quick switching between the first and second operating mode is ensured and, on the other hand, damping of pressure pulsations in the fluid line 4 are damped by means of the further pulsation damper 15, even in the second operating mode. Before the changeover from the second operating mode to the first operating mode, the further switching valve 16 is closed by the control electronics 10 again. Consequently, the further switching valve 16 too is subject only to low wear.