EP2741862A1

EP2741862A1 - Device for generating a pulsating fluid jet subjected to pressure

Info

Publication number: EP2741862A1
Application number: EP12725005.8A
Authority: EP
Inventors: Hermann-Josef David; Egon KÄSKE; Norbert Klinkhammer
Original assignee: Duerr Ecoclean GmbH
Current assignee: Ecoclean GmbH
Priority date: 2011-08-11
Filing date: 2012-05-31
Publication date: 2014-06-18
Anticipated expiration: 2032-05-31
Also published as: MX344279B; RU2014108917A; US9914238B2; RU2608488C2; DE102011080852A1; EP2741862B1; BR112014003105A8; BR112014003105A2; WO2013020732A1; CN103857475B; US20140165807A1; MX2014001620A; CN103857475A

Abstract

The invention relates to a device (20) for generating a pulsating fluid jet (16, 18) from fluid subjected to pressure. The device (20) contains a line system (36) having at least one nozzle (38, 40), which has a nozzle orifice (125), from which a fluid jet (16) of fluid subjected to pressure can exit. The device (20) has a chamber (22), in which a pressure wave generation arrangement (24) for generating fluid pressure waves (32) is constructed. The chamber (22) communicates with the line system (36) through an exit opening (34) for the generated fluid pressure waves (32). According to the invention, the device (20) contains an adjusting arrangement (31, 47, 62, 64) for controlling the amplitude A_Pof the fluid pressure waves (22) in the line system (36) upstream of the at least one nozzle orifice (125). With the adjusting arrangement(31, 47, 62, 64), it is possible to adjust a Helmholtz number He:= L/λ formed from the quotient of the path length L for the fluid pressure waves(22) in the line system (36) between the exit opening (34) of the chamber (22) and the at least one nozzle orifice (125) of the at least one nozzle (38, 40), and the wavelength λ of the fluid pressure waves (22) formed in the line system (36).

Description

Apparatus for generating a pulsating pressurized fluid jet Description

The invention relates to a device for generating a pulsating fluid jet of pressurized fluid with a conduit system containing at least one nozzle having a nozzle mouth from which a fluid jet of pressurized fluid can escape, and which has a chamber in a pressure wave generating device for generating fluid pressure waves is formed, which communicates with the line system through an outlet opening for the generated fluid pressure waves.

Such a device is known from WO 2006/097887 A1.

To efficiently process workpieces with fluid jets, e.g. With water jets, conventionally very high pressures must be generated, which may be 3000 bar or even higher. That requires a lot of energy. Working with corundum and sand, on the other hand, causes undesirable residues. Compared to the above-mentioned machining processes, machining with cutting tools has the disadvantage, for example, of materials with high hardness, that it is relatively expensive because of the wear of the cutting edges.

Against this background, the object of the invention is to provide a device for the efficient machining of the surface of workpieces with fluid jets, which can operate with comparatively low fluid pressures. In particular, it is an object of the invention to provide a device be provided, with which the surface of workpieces for the coating can be activated and / or the processing of coatings applied to workpieces allows such as the removal of overspray and / or the removal of layers on workpieces allows.

This object is achieved by a device of the type mentioned above, which contains an adjusting device for adjusting the amplitude of the fluid pressure waves in the line system before the at least one nozzle mouth, with which from the quotient of the path length L for the fluid pressure waves between the Outlet opening of the chamber and the at least one nozzle mouth of the at least one nozzle in the line system and the wavelength λ of the fluid pressure waves in the line system formed Helmholtz number He: = L / λ can be adjusted. The device according to the invention is particularly suitable for applying a fluid to a workpiece surface in the form of wash liquor and / or water and / or emulsion, in particular water-oil emulsion and / or oil. The invention is based on the idea that can be generated by coupling of vibration energy in the form of pressure waves in a fluid jet, in particular in a fluid jet, which is subjected to an increased pressure, which may be 20 bar, 30 bar or more, generate fluid pulses, in which the vibration energy is converted into kinetic energy. One idea of the invention is that the kinetic energy transferable to the fluid by generating pressure waves can be maximized by ensuring that the reflections of pressure waves in a conduit system for supplying pressurized fluid to a nozzle do not cancel the generated pressure waves but intensify due to interference. In a device according to the invention, therefore, the ratio of the effective path length which the pressure waves in the conduit system from the outlet opening of the chamber to the nozzle mouth of a nozzle cover and the wavelength of the fluid pressure waves, ie, a fluid pressure waves in the line system characterizing Helmholtz number are set.

For setting this Helmholtz number, the line system may include a first line piece and a at least partially received in the first line piece and communicating with this second line piece, which can be displaced relative to the first line piece in the longitudinal direction. It is advantageous in this case, if the second line piece, e.g. is guided linearly movable with a thread on the first line piece. Conveniently, a fixing device is provided, with which the second line piece can be fixed to the first line piece.

Alternatively, or in addition, to adjust the Helmholtz number, the device may include frequency adjustment means for adjusting the frequency of the generated fluid pressure waves. In fact, by varying the frequency of the fluid pressure waves, their wavelength in the fluid is also changed.

With a device according to the invention, workpieces can be roughened and cleaned, in particular without abrasive additives. The conduit system advantageously has a first conduit system section with a connection for a pressure pump and has a second conduit system section with a receptacle for the nozzle. It is advantageous if the first section and the second section are connected to a swivel joint. In that the second conduit system section in the rotary joint is coaxial with the first conduit system section about an axis of fluid passage formed in the second section. le axis can be oscillated and / or rotated, it is possible to produce regular or irregular structures in the surface of a workpiece bore. The device preferably contains a motor drive for moving the second line system section.

Conveniently, the line system has a first line system section with a connection for a pressure pump and has a second line system section, in which a plurality of nozzles are each arranged with a nozzle mouth, which are acted upon by separate line branches with fluid. In the separate line branches to the nozzles in each case a length-adjustable line for pressurized fluid is arranged. By adjusting the line, the path length of fluid pressure waves generated in the chamber between the nozzle mouth and the outlet port for fluid pressure waves of the chamber can be adjusted.

By preferably monotonically decreasing the effective cross-section of the conduits in the conduit system between the fluid pressure wave exit opening of the chamber and the nozzle mouth of the nozzle, it is ensured that the amplitude of the pressure waves in the flow direction of the fluid increases towards the nozzle mouth. In order for any air bubbles in the chamber can be removed, a vent valve is beneficial. Preferably, this vent valve is arranged so that even with a displacement of the device, these air bubbles can escape. For this purpose, the vent valve can for example be accommodated in an upper ceiling section of the chamber.

The chamber may have an opening separate from the exit opening for supplying high pressure fluid. This allows efficient delivery of fluid into the chamber. In order to ensure that the energy supplied to the pressure wave generating device has a good effect Grad is converted into pressure waves, it is advantageous if the pressure wave generating device is located in a Totwassergebiet the chamber. In order to reinforce the pressure waves coupled into the fluid, the chamber has a cross-section which is funnel-shaped in the direction of the outlet opening. It is advantageous to provide in the chamber a sensor for detecting pressure waves, so that the pressure wave generation can be monitored there. The sensor is conveniently designed as a pressure sensor and arranged in a portion of the chamber, which tapers in a funnel shape in the direction of the outlet opening.

The at least one nozzle may have a nozzle chamber whose cross-section is tapered towards the nozzle mouth. Extensive tests have shown that with the nozzle fluid pulses can be generated with a very large kinetic energy when the nozzle chamber in front of the nozzle mouth has a conically tapered portion with an obtuse angle α, preferably an opening angle α in the range 105 ° <α <180 °. Preferably, the at least one nozzle has a cylindrical, preferably circular cylindrical nozzle chamber with an opening arranged on the front side in the nozzle mouth. The fluid pulses that can be generated with such a nozzle are particularly suitable for removing material from aluminum materials. Due to cavitation, such a nozzle makes it possible to form fluid droplets which are particularly suitable for removing material and which are then contained in the pulsating fluid jet.

By providing a means for generating a gas stream at least partially enveloping the pulsating fluid steel, workpieces immersed in liquid with the pulsating fluid jet can be processed. Here, with the gas flow surrounding the high-pressure fluid jet, it ensures that the liquid into which the workpiece is immersed, does not burn off the fluid jet. The liquid surrounding the workpiece advantageously causes the attenuation of noise. Extensive tests have shown that when the at least one nozzle has a cup-shaped portion facing the workpiece, in which the pulsating fluid jet emerges from the nozzle mouth and whose opening cross-section widens in the direction pointing to the workpiece, a particularly good cleaning action is achieved for the workpiece can be. In order to be able to clean as large a workpiece surface as possible, it is expedient if the at least one nozzle is designed in the form of a nozzle nozzle which has a plurality of nozzle orifices.

It is advantageous to form a system with a device for generating a fluid jet with a workpiece receiving device in which the workpieces are acted upon by a pulsating fluid jet, and with a fluid collecting device to collect fluid released from the device connected to a pressure pump to return the collected fluid into the device. By having a measuring device for detecting material removed from a workpiece with a fluid jet, it is possible to monitor the removal of material caused by the pulsating fluid jet.

In order to modify the physical properties of components for certain applications, for example in order to increase their mechanical and thermal stability in internal combustion engines, these are finished with high quality coatings in certain places.

As a rule, these coatings require that the surface of these assemblies be prepared for coating, ie usually roughened or activated. For this purpose, it is known to work the workpieces with corundum rays or sandblasting. In addition, the surface Such workpieces are also mechanically machined by means of cutting tools in preparation for the coating.

An idea of the invention against this background is also that with a pulsating fluid jet in the surface of a workpiece structures can be produced which improve the adhesion of a coating on the surface and in particular allow the coating can be loaded with very large shear forces. It has namely been e.g. It has been shown that in particular the coating of aluminum materials by means of thermal spraying methods, such as flame spraying, plasma spraying, atmospheric plasma spraying or electric arc wire spraying, in particular, can significantly improve the tribological properties of aluminum assemblies. The arc wire spraying, for example, makes it possible to coat aluminum assemblies with an iron-based alloy having a carbon content of between 0.8 and 0.9 weight percent and containing dispersive friction reducing fillers in the form of graphite, molybdenum disulfide or tungsten disulfide. Coating materials also reduces the weight of engine components and allows compact designs, such as cylinder crankcases, in which the cylinder bores are at a reduced distance from each other compared to conventional housings.

It is advantageous to use one or more devices according to the invention for generating a fluid jet in a system for applying workpieces with fluid, which contains a controllable device for adjusting the pressure of the fluid supplied from the conduit system and the one with the Apparatus for adjusting the pressure and the pressure wave generating means connected to a computer unit Data memory has, in which a parameter map for the application-specific adjustment of the fluid pressure and / or the amplitude and / or the frequency of the pressure wave generating device can be generated with the fluid pressure waves is stored. In the parameter map can also be a favorable nozzle rotation speed depending on a material to be machined, in particular substrate and / or a given workpiece geometry and / or a workpiece surface finish, in particular a workpiece surface roughness, and / or a kind of workpiece contamination and / or a machining distance of a workpiece to be processed may be stored by the at least one nozzle mouth of the device. In addition, an advantageous angle of a pulsating high-pressure fluid jet generated by a corresponding device to a workpiece surface can also be stored in the parameter map.

Preferably, such a system includes a manipulator to move a fluid-to-be-pressurized workpiece relative to the device or apparatus relative to the workpiece. The manipulator can perform completely free movements, in particular linear movements or free movement of curves. In particular, an articulated robot with six axes of movement is provided as a manipulator.

One idea of the invention is also that it can be produced with a pulsating fluid jet, eg with an inventive device, to activate a surface of a workpiece for flame spraying or plasma spraying or arc wire spraying or to prepare it for gluing. In addition, it is an idea of the invention to use such a pulsating fluid jet to process a workpiece surface produced by means of flame spraying or plasma spraying or electric arc wire spraying. One finding of the invention is, in particular, that the preparation of the wall of a bore in a workpiece, in particular the adhesive properties of a workpiece surface produced by means of electric arc wire spraying, can be optimized if the nozzle is generated at an angle β with 0 ° <β <60 ° , Preferably ß ~ 45 °, is applied to the local surface normal of the wall inclined direction with a pulsating high-pressure fluid jet, and the nozzle is rotatably relative to the workpiece about the axis of the bore and translationally displaced in the direction of the axis of the bore , The distance of the nozzle opening to the workpiece surface is favorably between 10 mm and 150 mm.

The inventors have recognized, in particular, that a section of a workpiece can be finished by applying a surface coating to the workpiece in a first step and then, in a second step, processing and / or partially removing the coating by means of a pulsating fluid jet. This fluid jet can be generated in particular with a device according to the invention. The inventors have also recognized that the surface of a workpiece can be activated by means of a pulsating fluid jet, in particular by means of a pulsating fluid jet generated by a device according to the invention, in order to achieve the adhesive properties for the coating on the surface and the mechanical or thermal resilience to increase the coating. In particular, it is a finding of the inventors that can be activated by means of a pulsating fluid jet, which can be produced for example with a device according to the invention, the surface of an existing at least partially made of aluminum or aluminum alloy or magnesium alloys workpiece on this by means of thermal spraying (Arc wire spraying, LDS, plasma spraying, etc.) to apply a surface coating of ferrous material and then with a pulsating fluid jet, eg from a ner device according to the invention to edit. A finding of the inventors is also that by means of a pulsating fluid jet, which can be produced, for example, with a device according to the invention, the surface of a at least partially made of steel or gray cast workpiece can be activated to apply thereto by means of laser wire welding a surface coating of nickel-containing material , Moreover, it is an idea of the inventors that a coating applied to a workpiece made of steel or cast iron, aluminum, an aluminum alloy or a magnesium alloy is processed in the form of laser-wire-welded ferrous or nickel-containing material with a pulsating fluid jet can, in particular with a pulsating fluid jet from a device according to the invention. In the context of the invention, it may be provided in particular to first apply a large surface area over a surface coating and then subsequently to remove it again in small areas in edge regions.

In the following the invention will be explained in more detail with reference to the embodiments schematically illustrated in the drawing.

Show it:

1 shows a system with a device for generating a Pulsie- renden fluid jet with a workpiece.

Fig. 2 is a chamber for generating fluid pressure waves in the device; Fig. 3 is a length-adjustable line of the device for with

Pressurized fluid; 4 shows a nozzle which can be used in the device;

5 shows another nozzle which can be used in the device;

6 shows a nozzle which can be used in the device with a jet straightener;

FIG. 7 shows a section of the nozzle shown in FIG. 6 along the line VII - VII; FIG.

8 shows a device for generating a pulsating high-pressure fluid jet with nozzles arranged in a revolver;

Fig. 9 shows a portion of a device for generating a in a

Gas stream enveloped pulsating high-pressure fluid jet;

10 shows a section of a further device for generating a pulsating high-pressure pulsating fluid jet in a gas stream with a nozzle;

Fig. 1 1 shows a device for generating a pulsating high-pressure fluid jet with a nozzle rake; and

FIG. 12 shows a section of the device shown in FIG. 11 along the

Line XII - XII.

The system 10 in FIG. 1 is designed to activate the surface 12 of a cylindrical recess 14 in a workpiece 15 by means of pulsating fluid jets 16, 18 of water. For generating the fluid jets 16, 18, the system 10 has a device 20 with a chamber 22 in which a device 24 for generating fluid pressure waves 32 is formed. The device 24 is connected to a controllable frequency generator 31. The device 24 contains a piezoelectric crystal 28, which acts as an electromechanical transducer and is connected to a sonotrode 30. When the chamber 22 is filled with water, the sonotrode 30 in the water pressure waves 32 can be generated at a frequency v, which is preferably in the range 10 kHz <v <50 kHz.

For generating pressure waves, the piezoelectric crystal 28 is subjected to a high-frequency alternating voltage from a frequency generator 31. The frequency generator 31 is designed for generating ultrasonic frequencies, preferably ultrasonic frequencies in the range 10 kHz <v <50 kHz. By adjusting the frequency v and the amplitude A _{P of} the alternating voltage generated by the frequency generator 31, the wavelength λ of the pressure waves 32 in the line system 36 can be varied.

The chamber 22 is preferably tuned to a wavelength range of the fluid pressure waves 32 that can be generated with the sonotrode 30. For fluid pressure waves 32 in this wavelength range, the chamber 22 then acts as a resonance chamber.

The chamber 22 has an outlet opening 34 to a conduit system 36 which connects the chamber 22 with nozzles 38, 40. The piping system 36 has a chamber-side section 42 and includes a nozzle-side section 44. The chamber-side section 42 and the nozzle-side section 44 are connected by means of a pivot joint 46. In the rotary joint 46, the nozzle-side section 44 can be moved by means of a motorized rotary drive 48 about an axis coaxial to the fluid channel 50 axis oscillating and / or rotationally by means of a drive motor 54 by motor. The nozzles 38, 40 are located in the nozzle-side portion 44 of the conduit system 36 in line branches 56, 58, which are separated from each other. The fluid channel 60 formed in the nozzle-side section 44 is branched into the line branches 56, 58.

In the conduit branch 56 and the conduit branch 58 there is in each case a conduit section with a length-adjustable conduit 62, 64. The adjustable conduit 62, 64 includes a first conduit section 66, 68 and has an at least partially received in the first conduit section 66, 68 and the second conduit 70, 72 communicating therewith. The second conduit 70, 72 can be displaced coaxially relative to the first conduit 66, 68 in the longitudinal direction 74, 76 corresponding to the double arrow 78, 80.

In each case one of the nozzles 38, 40 is received in the second line piece 70, 72. By displacing the second line piece 70, 72 relative to the first line piece 66, 68, the effective path length 26 for pressure waves 32 between the outlet opening 34 and the workpiece side facing away from the nozzle mouth 82, 84 of the nozzles 38, 40 can be adjusted. The movement play for the line piece 70, 72 is tuned to the wavelength of the pressure waves 32. The movement play is favorably at least half a wavelength of the pressure waves 32. It is preferably in a range between 40 mm and 300 mm. Also in the section 42 of the conduit system 36, the conduit 43 can be displaced coaxially translationally by means of an adjusting device 47 relative to the conduit 45. The adjusting device 47 makes it possible to set the effective path length 26 for the pressure waves 32 in the line system 36. The adjusting device 47 can be adjusted by means of a (electric) motor drive (not shown). By adjusting the effective path length 26 of the pressure waves 32 in the conduit system 36 can be achieved that the Pressure waves 32 immediately before the workpiece facing away from the opening of the nozzle mouth of the nozzles 38, 40 have a vibration belly.

The adjusting device 47 thus acts as an adjusting device for adjusting, ie adjusting the amplitude A _{P of} the fluid pressure waves 22 in the line system 36 in front of the at least one nozzle mouth 125. With the adjusting device 47 can one from the quotient of the path length L for the fluid - Pressure waves 32 between the outlet opening 34 of the chamber 22 and the at least one nozzle mouth 125 of at least one nozzle 38, 40 in the conduit system 36 and the wavelength λ of the fluid pressure waves 22 in the conduit system 36 formed Helmholtz number He: = L / λ be set. The adjustable lines 62, 64 also act as adjusting devices for controlling the amplitude A _P of fluid pressure waves 32 in front of the corresponding nozzle mouth of the nozzle 38, 40.

In a modified embodiment, the chamber-side portion and the nozzle-side portion are made in one piece. In a further modified embodiment, the nozzle-side portion is mounted translationally displaceable on the chamber-side portion, without which a rotary joint is provided with a rotary drive. The translational movement of the nozzle-side section is realized manually and / or by means of spring force, by means of an electromagnet and / or by means of an electric linear motor. The adjustable frequency generator 31 is also such a setting device. By varying the frequency v of the alternating voltage generated by means of the frequency generator 31, it is possible to set the wavelength λ of the pressure waves 32 in the line system 36 and thus the amplitude A _{P of} the fluid pressure waves 22 in the line system 36, for example in front of the nozzle mouth 125. Starting from the outlet opening 34 of the cannisters 22, the effective line cross-section 86, 88 of the lines in the line system 36 decreases monotonously toward the nozzle mouth 82, 84 of the nozzles 38, 40. This causes the oscillation amplitude for the pressure of a pressure wave 32 in the direction of the guided according to the arrow 90 through the line 36 fluid idstroms to the nozzles 38, 40 increases towards.

It should be noted that the device 20 can be formed in a further modified embodiment with only one nozzle or with a plurality of nozzles.

In a further modified embodiment, the device 20 can be implemented with a frequency generator 31 whose frequency v can be varied without the line system containing length-adjustable lines.

The system 10 includes a pressure pump 91 and includes a reservoir 92 having a funnel-shaped outlet 93 for collecting fluid that passes from the nozzles 38, 40 to the workpiece 15. With the pressure pump 91, the fluid for generating pulsating fluid jets in the system 10 is circulated in a circuit. The pressure pump 91 is designed so that in chamber 22, a fluid pressure in the range between 40 bar and 150 bar and preferably a fluid pressure in the order of 100 bar can be generated and adjusted. By adjusting the fluid pressure in the chamber 22, the frequency v, and the amplitude A _{P of} the pressure waves, the size and spacing of liquid droplets in fluid jets 16, 18 exiting the nozzle 38, 40 can be varied. In a modified embodiment, the system 10 may instead of the pressure pump 91, a device with a high pressure pump for the Supplying high-pressure fluid contained in the conduit system 36 of the device, which ensures a fluid pressure which can be up to 3000 bar. In order to pressurize the fluid in the system with high pressure, in particular a high-pressure pump is suitable, which provides a fluid pressure between 300 bar and 600 bar.

Fig. 2 shows the chamber 22 for generating the fluid pressure waves 32 in the device 10. The chamber 22 has an opening 94 for supplying pressurized fluid from the high-pressure pump 91st The opening 94 is arranged separately from the outlet opening 34 in a lateral section of the chamber 22. The chamber 22 may be vented through an opening 96 with a controllable vent valve 98.

The sonotrode 30 is located in the chamber 22 in a dead water region 33 at a distance from the flow 35 of the fluid supplied through the opening 94 into the chamber 22 in the direction of the outlet opening 34.

To the outlet opening 34, the chamber 22 is formed in the section 99 with a funnel-shaped tapered cross-section. In section 99, the amplitude A _{P of} the pressure waves 32 generated by the sonotrode 30 of the device 24 is amplified. The graph 100 in FIG. 2 shows with the curve 101 the amplitude of the pressure of a pressure wave 32 in the chamber 22 as a function of the distance z from the surface 26 of the sonotrode 28. By adjusting the pressure P and the amplitude A _{P of} the pressure waves in FIG the chamber 22, the flow rate and the shape of the generated with the nozzles 38, 40 pulsating fluid jet can be adjusted.

In the chamber 22 is conveniently located a pressure sensor 102. The pressure sensor 102 is disposed in the portion 99 of the chamber 22. The pressure sensor 102 is connected to a measuring device 103, which is a display unit 105 has. The pressure sensor 102 can be used to detect the pressure fluctuations which are caused by the pressure waves 32 generated in the chamber 22 in the section 99. The display unit 105 thus allows an operator to monitor the operation of the device 20. Alternatively or additionally, the system 10 for monitoring the operation of the device 20 may also include a control computer 134 connected to the measuring device 103, which controls the device 24 for generating fluid pressure waves 32 and the pressure pump 91 as a function of the pressure fluctuation signal detected by the pressure sensor 102 ,

Alternatively or additionally, it is also possible to monitor the function of the device 20 in the system 10, e.g. the pulsating fluid jet 16, 18 exiting the nozzles 38, 40 is fed to an erosion meter (not shown). This erosion measuring device contains a test membrane to which the fluid jet is directed. In a proper operation of the device 20, a certain amount of material per unit time is removed from this test membrane. In order to detect the removal of material from this test membrane, the erosion measuring device contains a tactile sensor.

It is further alternatively or additionally provided to install a measuring device at a bypass to the outlet 93, which detects separated particles (for example a magnetic or optical particle counter), so that the function of the device 20 can be monitored in this way.

It is also advantageous if the control computer 134 contains a data memory 135 in which a parameter map 136 for the application-specific adjustment of the fluid pressure P and / or the amplitude A _P and / or the frequency v of the fluid pressure waves generated by the pressure wave generating means 32 and / or a nozzle rotation speed due a workpiece-specific application of the device 20 entered via an input unit 137 of the computer unit 136 is stored. The parameter map 136 sets in particular information about, for example, an empirically determined relationship between the abovementioned operating parameters and at least one of the following application parameters:

Type of material or substrate to be machined, workpiece geometry, target / actual workpiece surface finish, in particular workpiece surface roughness, type of workpiece contamination (eg chemical composition or hardness), machining distance of a workpiece to be machined for a particular nozzle diameter of the Nozzle mouth of the nozzles 38, 40.

To control the system 10, the control computer 134 is connected via a control line 138 to the pressure pump 91 and connected via lines 139, 140 to the measuring device 103 and the frequency generator 31. With master computer 134, e.g. the pressure that can be generated with the pressure pump can be regulated so that wear of the nozzles used in the device 20 is compensated by increasing the pump pressure.

FIG. 3 shows the section III of FIG. 1 with the length-adjustable line 62 in the device 20 in an enlarged view. The second line piece 70 is screwed into a thread 104 on the first line piece 66. The thread 104 is a fine thread. In the thread 104, the second line piece 70 can be displaced coaxially relative to the first line piece 66 corresponding to the double arrow 106. The second line piece 70 can be fixed to the first line piece 66 by means of a lock nut 110 arranged on the thread 108 of the second line piece 70 which is designed as a fine thread. The second line piece 70 passes through one arranged in the first line piece 66 Sealing ring 1 12, which prevents the escape of fluid between the first line piece 66 and the second line piece 70.

At the second line piece 70, the nozzle 36 is received. The nozzle 36 has an outside flange 1 14, which is pressed by means of a union nut 1 16 against a arranged on the end face 1 18 of the second line piece 70 sealing ring 1 19.

Fig. 4 shows a further nozzle 39 for use in the device. The nozzle 39 has a nozzle body 120 with a nozzle chamber 122 and a nozzle mouth 125. The nozzle mouth 125 has a length L _M , which is preferably about 6 mm. The nozzle mouth 125 is conveniently in the form of a hollow cylinder. The hollow cylinder has a diameter D _M , which is preferably in the range between 0.5 mm and 3 mm and advantageously 1 mm. In the section 126 facing the nozzle mouth 125, the nozzle chamber 122 is formed with a cross-section which tapers conically towards the nozzle mouth 125. The opening angle α of the cone in the section 126 of conically tapered cross section is obtuse. Preferably, for the opening angle a: 105 ° <a <180 °. With an opening angle of the cone close to 180 ° in the section 126, the pulsating high-pressure fluid jet can be generated with fluid droplets which have a particularly favorable shape for the removal of material. With the nozzle 39 high-pressure fluid jet pulses with liquid droplets can then be generated even at a fluid pressure in a range between 300 bar and 600 bar, whose kinetic energy is so great that thus efficient removal of material is possible in particular on metallic materials.

In a further modified embodiment, the opening angle α is greater than 180 °, in particular selected to 240 °. In this case, increased cavitation occurs in the nozzle mouth, which in turn promotes droplet formation at the nozzle outlet. FIG. 5 shows a nozzle 150 which has a nozzle body 151 with a nozzle chamber 152 designed as a circular cylinder. The nozzle chamber 152 has an axially disposed end opening 154 in the nozzle mouth 156. The nozzle mouth 156 is designed as a bore. The diameter D _{B of} the bore of the nozzle mouth is about 1/3 of the diameter D _{z of} the nozzle chamber. The nozzle mouth 156 has a length L _M which is about 6 mm. The use of such a nozzle in the device 20 described above allows even at a fluid pressure in the order of 60 bar the generation of pulsating fluid jets of water, with which metallic materials can be processed at a rapid material removal.

As nozzles for use in the device 20 are basically also so-called flat jet nozzles, star nozzles, square nozzles, triangular nozzles or nozzles that produce a fluid jet in the form of an omnidirectional.

An advantage of the device described above is that little or no cavitation occurs when operating with high-pressure liquid in the nozzles, so that then the wear of nozzles in the device is comparatively low.

Fig. 6 shows a further nozzle 170 for use in the device. The nozzle 170 has a nozzle body 171 with a nozzle chamber 172 and a nozzle mouth 173. The nozzle mouth has a length L _M which is about 6 mm and a diameter D _H ^s 1 mm. In the section 174 facing the nozzle mouth 173, the nozzle chamber 172 is formed with a cross-section which tapers conically towards the nozzle mouth 173. The opening angle α of the cone in the section 173 of conically tapered cross section is acute. A favorable value for the opening angle α of the cone is: α ~ 58 °. The nozzle 170 includes a jet director 175. The jet director 175 eliminates turbulence in the pressurized fluid in the nozzle chamber 172. FIG. 7 shows a section of the nozzle 170 along the line VII - VII in FIG. 6. The jet director 175 separates the Nozzle chamber 172 in the section 176 into four separate flow channels 177th

In the system 10 shown in FIG. 1, there is a device 130 for preparing the fluid fed into the chamber 22 with the pressure pump 91. In the device 130, the fluid circulated in the system 10 is freed of dirt particles. Particles and coating parts detached from a workpiece 15 are rinsed out of the workpiece in the system 10 with rinsing devices (not shown) and collected together with the fluid in a dirt tank in the device 130. The device 130 includes a filter system. With this filter system, the fluid supplied to the device 130 can remove the particles and contaminants detached from the workpiece, so as not to damage the device 20 for generating a pulsating fluid jet.

8 shows a system 210 for activating the surface 212 of cylinder head bores 214 in a cylinder crankcase 215 by means of pulsating high-pressure water jets 216. The assemblies in the system 210, the assemblies in the An described with reference to FIGS. 1 to 5 - If 10 correspond, are shown in FIG. 8 increased by the number 200 numerals reference numerals. In plant 210, there are a plurality of devices 220 disposed adjacent to each other for generating a pulsating high-pressure fluid jet. In each of the devices 220, the line system 236 is formed with a tool section 202 with a tool head 204, in which several re nozzles 238, 240 are added. The tool section 202 is arranged in the line system 236 by means of an automatically operable coupling device 206. The coupling device 206 enables the automatic replacement of the tool section 202 with a quick-change device (not shown) having a revolving magazine in which different tool heads are provided, which can be used in a device 220.

The nozzles 238, 240 may be e.g. have a geometry described with reference to FIGS. 4, 5, 6 and 7. The tool section 258 with the tool head 204 can be rotated about the axis 229 by means of a drive not further shown. The nozzles 238, 240 are supplied with water, which is supplied to the device 220 with a high-pressure pump 291. For adjusting the effective path length for pressure waves generated in the chamber 222, the conduit system 236 of the device 220 includes an adjusting device 247.

In plant 210 there is an industrial robot 21 1. The industrial robot 21 1 is a multi-axis manipulator for moving a workpiece in the form of a cylinder crankcase 215 relative to the device 220. In an alternative embodiment of the system 210, such an industrial robot may be provided with the device 220 for generating pulsating high-pressure Fluid jets by means of a handling device, in particular an industrial robot to move relative to the workpiece.

With the industrial robot 21 1, the cylinder crankcase 215 to the device 220 according to the double arrow 217 and lowered. With the pulsating high-pressure water jets 216 from the nozzles arranged in the turret 227, the surface of the material in the wall of the cylinder head bores 214 for an arc plasma coating activated by an adhesive structure is introduced into this surface. It has been shown that when the high-pressure water jet with a below the angle ß with 0 ° <ß <60 °, preferably ß ~ 45 ° inclined to the local surface normal of the wall direction with a pulsating high-pressure fluid jet is applied and thereby the Tool head 204 in the cylinder head bore 214 according to the arrow 221 rotatably moved and simultaneously translates in the direction of the axis of the bore corresponding to the double arrow 223, structures, such as helical threaded structures can be generated on which by means of flame spraying, plasma spraying or wire arc spraying in A layer produced by a cylinder head bore adheres particularly well. With the device according to the invention, different degrees of roughness at different or adjacent locations of a workpiece can be generated in a particularly simple manner. In particular, more or less smooth transitions between areas of different roughness can be generated.

FIG. 9 shows a portion of a device 320 for generating a pulsating high pressure fluid jet 316 which is enveloped in a gas stream 317. The assemblies in the device 320, which correspond to assemblies in the device 20 described with reference to FIGS. 1 to 4, are identified in FIG. 6 by number numbers increased by the number 300. The wrapping of the pulsating high-pressure fluid jet 316 in the gas stream 317 allows workpieces to be machined with the high pressure fluid jet 316 submerged in a liquid bath.

The device 320 has a nozzle 336 formed on a line piece 370. The line piece 370 is guided linearly movably in the line piece 366. It can be relocated according to the double arrow 378, so the effective path length of pressure waves between a chamber for generating pressure waves (not shown) and the side of the nozzle mouth 325 facing away from the workpiece can be adjusted. The line piece 370 is arranged in a nozzle 369 with a nozzle chamber 371, which has an opening 373 for supplying pressurized gaseous medium from a line 375 and which has an outlet opening 377, from which the gas stream 317 emerges. The nozzle chamber 369 and the line piece 370 can be displaced relative to each other according to the double arrow 379. By displacing the nozzle 369 relative to the nozzle 336, it is possible to adjust the shape of the fluid droplets in a pulsating high-pressure fluid jet 316 generated by the apparatus 320. 10 shows a section of a further device 380 for generating a pulsating high-pressure pulsed fluid jet 390 with a nozzle 382. The nozzle 382 has a nozzle chamber 384 with an axially arranged frontal opening 386 in the nozzle mouth 388. The nozzle mouth 388 is designed as a hole. The diameter D _{B of} the bore of the nozzle mouth is about 1 mm. At the front-side opening 386 in the nozzle chamber 384, the nozzle mouth 388 has a preferably rounded phase with the radius of curvature r <0.1 mm.

The workpiece-facing portion 381 of the nozzle 382 is configured as a funnel which widens in the direction of a pulsating fluid jet 390 emerging from the nozzle mouth 388 and has the aperture angle β ~ 60 °.

The shape of the workpiece-facing portion 381 of the nozzle 382 causes a gas flow passing along the outer wall 393 of the nozzle 382 to flow when the nozzle is in a liquid bath (not shown) removes liquid bath liquid from region 395 in front of the funnel-shaped section so that a pulsating high-pressure fluid jet can exit the nozzle orifice 388 unhindered and strike a workpiece located near die 382.

1 1 shows a device 420 for generating a pulsating high-pressure fluid jet 416, 417, 418 and 419. The device 420 has a chamber 422 with a device 424 for generating fluid pressure waves 432. The device 420 has a Line system 436 having a chamber side portion 442 and a nozzle side portion 444. For adjusting the path length for the fluid pressure waves 432 in the conduit system 436, the nozzle side portion 444 may be displaced relative to the chamber side portion 442 with an adjuster 447 corresponding to the double arrow 448.

FIG. 12 shows a section of the device 420 along line XII-XII in FIG. 11. In the nozzle-side portion 444 of the conduit system 436, there is a branched in the form of a rake line 438 with four nozzles, which are integrated into the line 438. The nozzles integrated in the line 438 each have a nozzle body 450, 452, 454 and 456 which can be displaced in accordance with the double arrow 460 and has a nozzle mouth. By displacing the nozzle bodies 450, 452, 454 and 456, it is possible to derive the quotient of the path length L ₄₅₀ , L ₄₅₂ , L ₄₅₄ and L ₄₅₆ for the fluid pressure waves between the outlet opening of the chamber 422 and the respective nozzle mouth of the Helmholtz numbers He _n : = L _n / λ set in the line system 436 and the wavelength λ of the fluid pressure waves 422 in the conduit system 436 so that the amplitude A _{P of} a fluid pressure wave generated in the chamber 422 before the relevant Nozzle mouth in the nozzle bodies 450, 452, 454 and 456 is maximum. The devices and systems described above are suitable for machining the surface of workpieces, for activating the surface of workpieces for coating, for processing and removing coatings on workpieces, and for cleaning workpieces.

The devices and systems described are particularly suitable for activating a workpiece surface, so that it can be coated by means of flame spraying or plasma spraying or electric arc wire spraying. The inventors have recognized that the microstructures with undercuts can be produced in the surface of workpieces by means of a corresponding pulsating high-pressure fluid jet. Thermal coatings which are applied to such a surface adhere particularly well here, because the molten particles can easily penetrate into these microstructures during coating due to the kinetic energy and due to capillary action, but then solidify there. A coating applied to a workpiece surface activated by means of a device and installation according to the invention therefore has, in particular, a high adhesive tensile strength, which may well be 30 MPa or more.

In order to ensure that the coating applied to a workpiece adheres well, it is advantageous if the surface to be coated of the workpiece is dried after activation in a device or equipment according to the invention, for example by panning, by air drying or by vacuum drying.

In particular, the inventors have recognized that a particularly good adhesion for a layer applied to the surface of a workpiece by means of flame spraying or plasma spraying or electric arc wire spraying can be achieved by first providing the surface of the workpiece with a pulsating high-pressure fluid jet in a device according to the invention. Layer is roughened to roughen this surface, and then the roughened surface of the workpiece with a defined contact pressure to rollers. The inventors have found that by rolling the mesoscopic projections of a roughened surface can be deformed and compressed so that this microstructures arise with undercuts, which have a high mechanical stability and in which the molten particles can easily penetrate during coating. The devices and systems described are also suitable for the machining of workpiece coatings, such as for the removal of overspray on workpieces that have been subjected to a coating process. In particular, by adjusting the angle of attack of the pulsating high-pressure fluid jet, its exit velocity from a nozzle mouth and the frequency of the pressure waves, ie the repetition rate for the high-pressure fluid jet, the edges of coating sections on a workpiece can be processed in a defined manner. In particular, edges can thus be produced which form a 45 ° angle with the workpiece surface.

A finding of the inventors is also that with a pulsating high-pressure fluid jet in the coating of workpieces, such as a means of Lichtbogendrahtspntzen (LDS) generated coating on the cylinder head surfaces of internal combustion engines, a bevel can be introduced without here as in the processing with cutting tools There is a risk that this coating will detach from the workpiece during processing with the pulsating high-pressure fluid jets.

The devices and systems according to the invention are suitable, in particular, for processing a workpiece surface produced by means of flame spraying or plasma spraying or arc wire spraying and / or for Deburring of a workpiece and / or for the removal of dirt from a workpiece and / or for the removal of layers on a workpiece. The devices and systems according to the invention are also suitable for roughening workpiece surfaces in order to prepare them for a material-fit joining (gluing, welding, soldering).

The devices and installations according to the invention may e.g. be operated with fluid in the form of wash liquor and / or water and / or emulsion, in particular water-oil emulsion and / or oil. In order to avoid the corrosion of the devices and systems according to the invention, it is advantageous to mix anti-corrosion agents with the fluid used for machining workpieces.

According to the invention with the devices and systems described above, portions of workpieces or workpieces are at least partially made of aluminum or magnesium, wherein the surface coating is applied by laser wire welding iron-containing material or the workpiece consists at least partially of steel or gray cast iron and the surface coating with - Laser-wire welding applied nickel-containing material.

According to the invention, with the devices and installations described above, the surface of workpieces can also be compacted by applying a pulsating fluid jet to the workpiece. The inventors have recognized in particular that by treating cylinder crankcases made of die-cast aluminum, the voids interfering with a coating in the region of the cylinder running surfaces can be closed off with water using a pulsating high-pressure fluid jet of water. In summary, in particular the following preferred features of the invention are to be noted: The invention relates to a device 20 for the Generating a pulsating fluid jet 16, 18 from pressurized fluid. The apparatus 20 includes a conduit system 36 having at least one nozzle 38, 40 having a nozzle mouth 125 from which a pulsating fluid jet of pressurized fluid may exit. The device 20 has a chamber 22 in which a pressure wave generating means 24 for generating fluid pressure waves 32 is formed. The chamber 22 communicates with the conduit system 36 through an exit port 34 for the fluid pressure waves 32 generated. The apparatus 20 includes an adjuster 31, 47, 62, 64 for controlling the amplitude A _{P of} the fluid pressure waves 22 in the conduit system 36 The at least one nozzle mouth 125. With Einsteileinrichtung 31, 47, 62, 64 can be a quotient of the path length L for the fluid pressure waves 22 between the outlet opening 34 of the chamber 22 and the at least one nozzle mouth 125 of the at least one nozzle 38, 40 in Helmholtz number He: = L / λ set in line system 36 and wavelength λ of fluid pressure waves 22 in the line system (36).

Claims

claims

1 . Apparatus (20) for generating a pulsating fluid jet (16, 18) of pressurized fluid with a conduit system (36) including at least one nozzle (38, 40) having a nozzle mouth (125) from which a pulsating fluid Fluid jet (16, 18) can escape from pressurized fluid, and with a chamber (22) in which a pressure wave generating means (24) for generating fluid pressure waves (32) is formed, which communicates with the conduit system (36 ) communicates through an exit opening (34) for the generated fluid pressure waves (32), characterized by adjusting means (31, 47, 62, 64) for controlling the amplitude A _{P of} the fluid pressure waves (22) in the conduit system (36 ) in front of the at least one nozzle mouth (125), with one of the quotient of the

Path length L for the fluid pressure waves (22) between the outlet opening (34) of the chamber (22) and the at least one nozzle mouth (125) of the at least one nozzle (38, 40) in the conduit system (36) and the wavelength λ of the fluid Helmholtz number He: = L / λ can be set in the line system (36).

2. Apparatus according to claim 1, characterized in that the adjusting means comprises at least one in the line system (36) arranged in length adjustable line (62, 64) for pressurized fluid (41), with which the path length (26 ) of in the

Chamber (22) generated fluid pressure waves (32) between the less at least one nozzle mouth (125) of the at least one nozzle (38, 40) and the outlet opening (34) for fluid pressure waves (32) of the chamber (22) can be adjusted.

Apparatus according to claim 2, characterized in that the adjustable line (62, 64) includes a first line piece (66, 68) and a at least partially in the first line piece (66, 68) received and communicating with this second line piece (70, 72 ), which can be displaced relative to the first line piece (66, 68) in its longitudinal direction.

Device according to one of claims 1 to 3, characterized in that the adjusting means (31) for adjusting the frequency of the pressure wave generating means (24) generated fluid pressure waves (32).

Device according to one of claims 1 to 4, characterized in that the conduit system (36) has a first conduit system section (42) with an opening for supplying fluid from a high-pressure pump (91) and a second conduit system section (44) with the at least one Nozzle (38), wherein the first portion (42) and the second portion (44) are connected to a pivot (16).

Apparatus according to claim 5, characterized in that the second conduit system portion (42) in the pivot (16) relative to the first conduit system portion (42) about a to the axis (52) formed in the second portion (42) fluid channel (60). coaxial axis oscillating and / or rotating can be moved.

7. Device according to one of claims 1 to 6, characterized in that the line system has a first line system section (42) having an opening (34) for supplying liquid of a high pressure pump (91) and a second line system section (44) a plurality of nozzles (38, 40) which are acted upon by separate line branches (56, 58) with fluid (41).

8. Apparatus according to claim 7, characterized in that in the separate line branches (56, 58) to the nozzles (38,

40) is arranged in each case one in the length (62, 64) adjustable line for pressurized fluid, with which the path length (26) of in the chamber (22) generated fluid pressure waves (32) between a nozzle mouth (125) via the line branch (56, 58) with fluid (41) acted upon nozzle (38, 40) and the outlet opening (34) for fluid

Pressure waves (32) of the chamber (22) can be adjusted.

9. Device according to one of claims 1 to 8, characterized in that the effective cross section of the lines in the line system (36) between the outlet opening (34) for fluid

Pressure waves (32) of the chamber (22) and the nozzle mouth (125) of the nozzle (38, 40) decreases.

10. Device according to one of claims 1 to 9, characterized in that the chamber (22) has an opening (94) spaced from the outlet opening (34) for the supply of high-pressure fluid (41) and that Nozzle (38, 40) supplied fluid (41) is guided through the chamber (22). 1 1. Device according to one of claims 1 to 10, characterized in that the pressure wave generating means (24) in one Totwassergebiet (33) of the chamber (22) is positioned.

12. Device according to one of claims 1 to 1 1, characterized in that the chamber (22) has a portion (99) with a to the outlet opening (34) funnel-shaped tapering cross-section.

13. Device according to one of claims 1 to 12, characterized in that the at least one nozzle (38, 40, 170) has a nozzle chamber (122, 172) having a portion (126, 174) with a to the nozzle mouth ( 125, 173) has a tapered cross section.

14. The apparatus according to claim 13, characterized in that the portion (126) of the nozzle chamber (122) is tapered conically with an obtuse opening angle α, preferably with an opening angle, α for which applies: 105 ° <α <180 ° or the portion (174) of the nozzle chamber (172) is conically tapered with an acute opening angle α, which is preferably α ~ 58 °, wherein a jet straightener (75) is arranged in the nozzle chamber (172) for avoiding or reducing turbulences ,

15. Device according to one of claims 1 to 14, characterized in that the at least one nozzle (150) has a cylindrical, preferably circular cylindrical nozzle chamber (152) having a frontally arranged opening (154) in the nozzle mouth (156).

16. Device according to one of claims 1 to 15, characterized in that means (369, 370) for generating a pulsating fluid steel (316) at least partially enveloping the gas stream (317) is provided.

17. Plant (10) having a device (20) designed according to one of claims 1 to 16 for generating a fluid jet (16, 18) from pressurized fluid, characterized by a receiving device (92) for workpieces (15) in which the workpieces (15) being exposed to a pulsating fluid jet (16, 18) and fluid collecting means (93) for collecting fluid (41) released from the device (20) connected to a pressure pump (91), to return the collected fluid (41) to the device (20).

18. Plant (10) with a particular according to one of claims 1 to 16 formed device (20) for generating a fluid jet (16, 18) from pressurized fluid, in particular system according to claim 17, characterized by a controllable device for the Adjusting the pressure of fluid supplied from the conduit system (36) and a computer unit (134) connected to the means (91) for adjusting the pressure P and the pressure wave generating means (24) and having a data memory (135) in which a parameter map ( 136) for the application-specific setting of the fluid pressure P and / or the amplitude A _P and / or the frequency v of the fluid pressure waves (32) that can be generated by the pressure wave generating device (24) and / or a nozzle rotation speed depending on a material to be processed, in particular substrate and / or depending on a workpiece geometry and / or a workpiece surface finish, in especially one

Workpiece surface roughness, and / or a type of workpiece contamination and / or a machining distance of a workpiece to be machined from the at least one nozzle mouth (120) is stored. Use of a device according to one of claims 1 to 16 or a device according to claim 17 or 18 for activating a workpiece surface (212) to be coated by flame spraying or plasma spraying or arc wire spraying, and / or for processing by means of flame spraying or plasma spraying or wire arc spraying generated workpiece surface, and / or for deburring a workpiece and / or for removing dirt from a workpiece, and / or for the removal of layers on a workpiece and / or for applying a workpiece surface with fluid in the form of

Wash liquor and / or water and / or emulsion, in particular water-oil emulsion and / or oil, and / or for compacting a workpiece surface by subjecting the workpiece surface to fluid, in particular water.

20. A method of machining the wall (212) of a bore (214) in a workpiece (215) having a device according to any one of claims 1 to 16, wherein the wall (212) of the bore is provided with a pulsating high pressure Fluid jet is acted upon by a nozzle which is inclined at an angle ß in the range 0 ° <ß <60 °, preferably an angle ß ~ 45 ° to the local surface normal of the wall, wherein the nozzle relative to the workpiece about the axis (229 ) of the bore (214) is rotationally displaced and translationally displaced in the direction of the axis (229) of the bore. Method for refining a section of a workpiece in which a surface coating is applied to the section of the workpiece and in which in a second step the coating is processed by means of a pulsating high-pressure fluid jet, preferably with a device formed according to one of claims 1 to 16 is produced.

A method according to claim 21, characterized in that the portion of the workpiece is activated prior to the application of the surface coating by means of a pulsating high-pressure fluid jet, which is preferably produced with a device according to one of claims 1 to 16.