JP2004114042A - Ultrasonic standing wave atomizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a spray mist of paint suitable for painting a workpiece.
SOLUTION: The ultrasonic standing wave atomizer device of the present invention includes a sonotrode (14) and a component (16) arranged facing the sonotrode (14). During operation, an ultrasonic field of a standing wave is formed in the space between the sonotrode (14) and the component (16). The apparatus further comprises at least one paint supply device by which the paint can be delivered in the vicinity of the region where the particle velocity of the sound of the ultrasonic field is maximum. The at least one paint supply device is formed substantially as a piece of pipe (26) in the region of the standing wave ultrasonic field. The shape of the facing surfaces (18, 20) of the sonotrode (14) and the component (16) has the effect of making the sound particle velocity substantially the same along the pipe piece (26).
[Selection diagram] Fig. 1 (a)

Description

The present invention relates to an ultrasonic standing wave atomizer device for generating a spray mist of paint for painting a workpiece.

High-speed atomizers, commonly known today, are favored and used today for painting workpieces, especially in high-volume applications, such as are often done in the automotive industry. In the case of high rotational speed atomization, the paint passes through the interior of the metal bell and reaches its front side. Here, the front side of the metal bell-shaped member faces the workpiece. The metal bell is typically driven by a turbine of compressed air and rotates at a maximum speed of 80,000 revolutions per minute. The centrifugal force acting in this case then causes the paint to reach the front edge of the bell, where it breaks up into fine droplets. This has the effect that the droplet size of the spray mist of the paint falls in the range of 10 μm to 60 μm (required for proper quality of the coating of the paint).

According to a consideration of the principle that has become generally known, in principle, paints can also be atomized by ultrasonic standing-wave atomization. However, according to these considerations of this principle, although the average droplet size during atomization is measured from 100 μm to 200 μm, larger droplets are also generated at the same time. However, such large size droplets have a negative effect on the quality of the paint film. This makes the use of ultrasonic standing waves in coating technology less attractive.

In view of such prior art, an object of the present invention is to provide an ultrasonic standing wave atomizer device. The use of this device makes it possible to produce a spray mist of paint of suitable quality for use in painting technology.

This object is achieved by the ultrasonic standing wave atomizer of the present invention. SUMMARY OF THE INVENTION The present invention is an ultrasonic standing wave atomizer apparatus for generating a spray mist of paint for painting a workpiece, comprising a sonotrode and a component disposed face-to-face with the sonotrode. In this case, an ultrasonic field of a standing wave is formed in a space between the sonotrode and the component. Further, the ultrasonic standing wave atomizer device includes at least one paint supply device, and the paint supply device can feed the paint near an area where the particle velocity of the sound of the ultrasonic field is maximum. In this case, the paint supply device is substantially configured as a piece of pipe in the region of the ultrasonic field of the standing wave. Finally, the shape of the opposing surface portions of the sonotrode and the component has the effect of making the sound particle velocity substantially the same along the pipe piece.

In this regard, it is firstly advantageous to be able to feed the paint in the vicinity of the sound particle velocity of the maximum ultrasonic field. This is because the most preferable point is in the vicinity of the region where the maximum value is obtained in the ultrasonic field in order to cause the atomization of the paint. Further in accordance with the idea of the present invention, the opposing surface portions of the sonotrode and the component are configured to make the sound particle velocity substantially the same along the piece of pipe. This part of the idea of the present invention is also aimed at the atomization of the best possible, i.e. the feasible and most uniform, the finest possible droplet state paint.

By configuring the sonotrode and the component according to the method according to the invention, paint is fed through the pipe piece into the region where the sound particle velocity is at a maximum, but the paint on the pipe piece The paint remaining on the outlet of the pipe or flowing along the outside of the pipe piece is also atomized by the maximum value of the sound particle velocity existing there, and fine paint droplets become. Assuming that the maximum value of the sound particle velocity appears only near the paint outlet, as in the conventional case, the paint flowing along the outer side of the piece of pipe will cause relatively large paint droplets. Occasionally, however, they will separate from the pipe pieces, thereby causing defects in the coating. The formation of such unacceptably large droplets in the painting process is prevented by the ultrasonic standing wave atomizer device according to the present invention. In a preferred method, a mist of spray paint having a quality very well adapted for use in painting technology is thus formed.

In an advantageous embodiment of the ultrasonic standing wave atomizer device according to the invention, said component is a second sonotrode. In this way, the required standing wave ultrasonic field can be formed and controlled in a particularly effective manner.

In a further advantageous form of the present subject matter, the opposing surface portions of the sonotrode and the component are formed as hollow cylinders. The axis of the cylinder is arranged parallel to the longitudinal axis of the pipe piece. In this way, it is ensured that the ultrasonic field of the standing wave is formed in a form corresponding to the shape of the pipe piece. As a result, the distribution of the maximum value of the particle velocity of the corresponding sound has a similar form.

Alternatively, in other words, such a device according to the present invention not only causes the atomization of paint directly at the point of paint exit, but also the atomization along the relatively large area of the pipe piece. It can be realized.

In a further advantageous form of the subject of the present invention, the enclosing element is arranged around a space between the sonotrode and the component, with a gap in the direction in which the paint is sprayed, and in other directions. Substantially prevents the emission of ultrasonic waves. In this respect, in particular, the enclosing element is formed in a U-shaped configuration. In this way, the effect is achieved that the formed ultrasound is used for atomization at a relatively high rate, while the unused rate of ultrasound radiation is kept as small as possible. .

更 に A more effective form of the subject of the present invention aims at the same effect as that realized with the enclosing element. According to the invention, a ring or ring segment is arranged around the paint outlet opening of the pipe piece. The paint outlet opening of the pipe piece is in the cylindrical shape defined by the outer peripheral surface of the inner ring-shaped member, or of the cylindrical segment defined by the radially inner outer peripheral surface of the ring segment-shaped member. Placed inside.

Further advantageous forms of the atomizer device according to the invention can be found in the dependent claims.

The invention, its advantages and further refinements of the invention are specified and described based on the illustrative embodiments illustrated in the accompanying drawings.

FIG. 1A shows a first ultrasonic standing wave atomizer device 10 based on the present invention. This figure is represented by the isometric projection method. The rectangular coordinates are indicated by arrows in the X, Y, and Z directions, and are denoted by reference numeral 12. It should be noted that this figure is only intended to show the outline of the apparatus, and therefore, the exact relative size cannot be known from this figure.

The first sonotrode 14 is disposed so as to face the first reflecting body 16 with each other. In this case, the sonotrode 14 is symbolically represented in this figure by a cylindrical base body and a sound body 21. The sound body 21 protrudes from the end face of the cylindrical base body and faces the reflecting body 16. The shape of the sound body 21 is substantially a rectangular parallelepiped, and the end face facing the first reflecting body 16 has a shape corresponding to a part of the surface formed by the virtual hollow cylinder. A first dashed line 17 and a second dashed line 19 are drawn above the first sound face 18 to represent this shape. This first broken line 17 is parallel to the virtual center axis of the hollow cylinder. Furthermore, the point of contact between the relevant edge line of the first sound face 18 and the first dashed line 17 is exactly located in the center of the relevant edge line.

The second broken line 19 corresponds to the arc segment. The first dashed line 17 and the second dashed line 19 intersect each other at their respective midpoints, and are perpendicular to each other at this intersection. From this it can be seen that the end of the second dashed line 19 consequently exactly matches the midpoint of the two relevant edge lines of the first sound face 18. At the intersection of the first dashed line 17 and the second dashed line 19, a first center line 24 is drawn perpendicular to the first sound face 18.

The first reflective body 16 is very similar to the sound body 21 in its shape. Thus, the second sound face 22 can be represented in a similar manner as the first sound face 18. Accordingly, two broken lines corresponding to the first broken line 17 and the second broken line 19 are shown. Further, the first reflecting body 16 is arranged such that the first broken line 17 and the corresponding line on the first reflecting body 16 are parallel to each other. Further, the intersection of the two lines on the first reflecting body 16 corresponding to the first broken line 17 and the second broken line 19 is located on the first center line 24 described above. As a result, the first sound face 18 and the second sound face 22 are arranged to face each other exactly.

A first pipe piece 26 is drawn in the space between the first sound face 18 and the second sound face 22. The free end of the first pipe piece 26 is precisely located at an intermediate position between the first sound face 18 and the second sound face 22 and further directly above the first center line 24. Has ended. The first pipe piece 26 is formed so as to be straight in the longitudinal direction and parallel to the first broken line 17.

Furthermore, the pipe piece 26 is a part of a paint supply device (other parts are not shown). The paint supply device supplies a required amount of paint, and the supplied paint is atomized by the first ultrasonic standing wave atomizer apparatus 10. Thus, the other end of the pipe piece 26 is depicted as terminating in free space, where in fact there is a connection to the paint supply device.

代表 Typical values for the supply rate of the paint are 200 mL / min to 400 mL / min. Furthermore, it is easy to come up with a paint supply device for the plurality of pipe pieces 26 using the paint supply device, and it is within the scope of the idea of the present invention. The free ends of the plurality of pipe pieces are then respectively arranged in the ultrasonic field at the locations where the particle velocities of different sounds have a maximum value.

In order to represent the effective position of the first end of the pipe piece 26, a graphic showing the sound particle velocity profile of the ultrasonic field is drawn in this area. The X-axis of this figure is above the first center line 24 and the Y-axis of this figure is parallel to the longitudinal axis of the pipe piece 26. The two sinusoidal half-waves of the sound particle velocity are depicted in this figure, arranged offset from each other in the Y direction. Each of the above two half-waves becomes zero at the intersection with the Y axis, and reaches a maximum value when it coincides with the longitudinal axis of the pipe piece 26.

The above diagram depicting the sound particle velocity wave shows that a standing wave ultrasonic field is formed in the space between the first sonotrode 14 and the first reflecting body 16. Intended. Furthermore, the pipe piece 26 is arranged as a part of the above-mentioned paint supply device so that the paint is sent out near the point where the particle velocity of the sound formed in the ultrasonic field becomes the maximum value. It is shown.

The following is particularly advantageous, which is likewise illustrated by the above figures. That is, the shapes of the first sonotrode 14 and the first reflecting body 16 according to the present invention form an ultrasonic field due to the standing wave of the ultrasonic wave, and this ultrasonic field is, as in the conventional case, a specific one. Not only does the maximum value of the sound particle velocity appear at the point, but as shown here, along some axis, specifically along the Y direction and along the central axis of the pipe piece 26 I do. Such a maximum spreads linearly over a distance, which can be predetermined by the dimensions of the first sonotrode 14 and the first reflective body 16, and furthermore the sound particles The maximum value of the speed is practically hardly reduced.

In other words, this means that the following effects are realized by the device according to the present invention. That is, in the space between the first sonotrode 14 and the first reflecting body 16, the sound particle velocity is substantially the same along the pipe piece 26. Also, in any case, the atomization occurs over the distance detailed above, since the sound particle velocity is reduced only slightly.

The replacement of the first reflective body 16 of the device according to the invention with a further sonotrode can also be very easily and easily envisaged. This makes it possible to create a stronger ultrasound field and to control it particularly precisely. Accordingly, the above atomization is further improved, thereby improving the quality of the spray mist of the paint.

更 Further advantages for the formation of the ultrasonic field of the standing wave can be obtained by configuring as follows. That is, the width of the first reflecting body 16 or the width 13 of the first sound face 18 of the first sonotrode 14 (ie, the size in the Z direction shown in this figure) is changed by the first sound. The hollow cylinder formed by the face on which the face 18 or the second sound face 22 is formed is set to be the same as the radius 15 described above.

分 か る In this case, it can be seen that a particularly preferable device is realized, and a particularly excellent and appropriate standing wave ultrasonic field is realized.

FIG. 1B shows a second ultrasonic standing wave atomizer device 20. This device has substantially the same configuration as the device shown in FIG. Therefore, the same reference numerals are given to the elements already shown in FIG. Shown in this figure are a second sonotrode 28 and a second reflective body 32. These are arranged and assembled in a manner similar to the previous first sonotrode 14 and first reflective body 16.

However, only the related sound faces are different. That is, the third sound face 34 and the fourth sound face 36 are in each case formed by three individual flat partial surfaces, ie as polyhedral surfaces. In this case, the partial surfaces of each of the sound faces 34, 36 are arranged to approximate the profile of the hollow cylinder of the corresponding sound face 18, 22 (FIG. 1 (a)). That is, an ultrasonic standing wave field is formed in a space between the second sonotrode 28 and the second reflecting body 32, so that the maximum value of the sound particle velocity is increased over a certain distance by the pipe piece. Along the central axis of 26, they also appear.

FIG. 1C shows a further apparatus according to the present invention, that is, a third ultrasonic standing wave atomizer apparatus 30. This device has a third sonotrode 38 and a third reflective body 40. As already described in the previous drawings, the same elements as those in the previous drawings are denoted by the same reference numerals in this drawing as in the previous drawings. 1A and 1B is a fifth sound face 42 of the third sonotrode 38 and a sixth sound face 44 of the third reflecting body 40. . They are formed on the substantially cylindrical base bodies of the third sonotrode 38 and the third reflective body 40, respectively.

However, the fifth sound face 42 and the sixth sound face 44 are formed so as to correspond to the shape of the hollow cylinder. The imaginary center line of the hollow cylinder is similarly arranged parallel to the center axis of the pipe piece 26. When it comes to creating a standing wave ultrasonic field, this is ultimately nothing less than creating a field similar to that already described in FIGS. 1 (a) and 1 (b). This is likewise symbolically represented by a loop of two sound particle velocities drawn.

形態 All of the embodiments illustrating the ultrasonic standing wave atomizer device according to the present invention have common features. That is, the sonotrode 14, 28, 38 and the reflective bodies 16, 32, 40 are such that the sound particle velocity is particularly large in the region of the paint outlet (ie in the region of the first end of the pipe piece 26). Is substantially identical along the piece of pipe 26 and, at worst, slightly reduced.

This is because, as a result of the ultrasonic field formed therein, with respect to the sheet of paint formed at the outlet of the paint, even if the paint flows along the outer circumference of said pipe piece 26, This means that the sheet is atomized into the required relatively small droplets. As a result, the formation of relatively large droplets which impair the quality of the paint is effectively prevented.

An ultrasonic field is created more uniformly along the pipe piece 26. As a result, atomization into acceptable and acceptably small droplets along the pipe piece 26 occurs to meet the required quality of the paint.

FIG. 2 shows an apparatus based on FIG. This device comprises a first sonotrode 14, a first reflecting body 16 and a pipe piece 26, and further comprises a housing 46. The housing 46 is formed in a U-shape, and its legs (or sides) surround the first sonotrode 14, the cuboid sound body 21 and the first reflecting body 16 from three sides. Is formed. That is, the distance between the side portion of the housing 46 and the side surface of the sound body 21 opposed thereto and the distance between the side portion of the housing 46 and the opposed side surface of the first reflective body 16 do not contact each other. And it is arranged so as to be as small as possible.

The base of the housing 46 is supported by the two legs described above, through which the pipe piece 26 extends. However, the required clearance in the base part is only shown in this figure for this purpose and is not represented more technically. The housing 46 prevents or reduces the emission of ultrasonic waves in spatial directions that do not correspond to the painting direction.

FIG. 3 shows still another embodiment of the fourth ultrasonic standing wave atomizer device 50 according to the present invention. This figure shows, in particular, an advantageous configuration of the first end 52 of the pipe piece 26 with the sheet-like ring 48. In this case, a sheet-like ring 48 is attached to the pipe piece 26 near the first end 52. The paint outlet opening at the first end 52 projects only slightly into the cylindrical space bounded by the sheet-like ring 48. The sheet-like ring 48 is arranged so that spraying on a workpiece (not shown) can be performed through one of the end faces of the cylindrical space. Radiation of the ultrasonic waves in the radial direction of the cylindrical space is eliminated or reduced in an effective manner.

塗料 The paint particles 54 shown in this example are atomized by the ultrasonic field formed therein. Such paint particles 54 are depicted in an exaggerated size. In practice, paint particles with a size of less than 60 μm are reliably formed there, ie with a random distribution of particles to achieve a coating of the appropriate quality.

FIG. 4 shows a further example of possibilities for developing the subject of the invention. This detailed view is based on FIG. 3 and therefore the same parts are given the same reference numbers. However, in this figure, a sheet-like ring segment 56 is located at the first end 52 of the pipe piece 26 instead of the sheet-like ring 48 shown in FIG.

The sheet-like ring segment 56 extends over a range of approximately 210 degrees of the arc in this example, but may extend over a wider range. The width of the sheet-shaped ring segment 56 or the width of the sheet-shaped ring 48 can be set not only to a value smaller than the diameter of the pipe piece 26 but also to a value larger than the diameter. is there. By selecting a larger width for the sheet-like ring segment 56 or the sheet-like ring 48, the emission of ultrasonic waves in the direction covered by the sheet-like ring segment 56 or the sheet-like ring 48 is reduced. The effect to make it increase.

What is applicable to all of the aspects of the present subject matter is the use of air blowing to prevent the sonotrode or reflective body from getting wet. The spray mist of the paint produced by the ultrasonic standing wave atomizer device according to the present invention is directed by so-called cleaning air or directing air. Further, the droplets of the spray mist of the paint can be charged using static electricity, or more precisely, using a charging device. This charging device is already known in principle from painting processes which are carried out using atomizers with a high rotational speed. In particular, the principle of internal charging, external charging or a combination of internal and external charging is known for such charging devices.

In the case of so-called internal charging, a suitable high electrostatic potential (eg 40,000 volts) is applied to the paint while it is already in the paint supply device. On the other hand, the workpiece to be painted is connected to ground. In this way, the electrostatically charged particles of the paint tend to move towards the workpiece to be painted, thus supporting the painting process.

In the case of so-called external charging, several high-voltage electrodes are usually arranged around the paint outlet of the paint supply device. The paint particles pass through the high voltage electrostatic field created by these electrodes, thus charging the paint particles electrostatically. In this case also, the workpiece is connected to ground. Thereby, the electrostatically charged particles of the paint are consequently directed towards the workpiece.

The figure which shows the 1st ultrasonic standing wave atomizer apparatus. The figure which shows a 2nd ultrasonic standing wave atomizer apparatus. The figure which shows the 3rd ultrasonic standing wave atomizer apparatus. The figure which shows the 2nd ultrasonic standing wave atomizer apparatus provided with the half shell. The figure which shows a 1st paint supply device. The figure which shows a 2nd paint supply device.

Explanation of reference numerals

Reference numeral 10: first ultrasonic standing wave atomizer device, 12: directional arrow, 13: width, 14: first sonotrode, 15: radius, 16: first One reflection body, 17 ... first dashed line, 18 ... first sound face, 19 ... second dashed line, 20 ... second ultrasonic standing wave atomizer device, 21 ... A second sound body, 22 a second sound face, 24 a first centerline, 26 a piece of pipe, 28 a second sonotrode, 30 a first Three ultrasonic standing wave atomizer devices, 32 ... second reflecting body, 34 ... third sound face, 36 ... fourth sound face, 38 ... third sonotrode, 40 ... Third reflective body, 42 ... Fifth sound face 44 a sixth sound face, 46 a housing, 48 a sheet ring, 50 a fourth ultrasonic standing wave atomizer device, 52 a first end, 54 a ..Particles of paint, 56 ... Segment of sheet ring.

Claims (18)

An ultrasonic standing wave atomizer device (10, 20, 30) for generating a spray mist of paint for painting a workpiece, comprising:
A sonotrode (14, 28, 38) and a component (16, 32, 40) arranged opposite to the sonotrode, and in operation, the sonotrode (14, 28, 38) and the component (16) , 32, 40), an ultrasonic field of a standing wave is formed in the intermediate space;
Comprising at least one paint supply device, by means of which the paint can be delivered in the vicinity of the region where the sound particle velocity of the ultrasonic field is at a maximum;
With the following features:
The at least one paint supply device is configured substantially as a piece of pipe (26) in the region of the standing wave ultrasonic field;
The shape of the opposing surfaces (18, 22) of the sonotrode (14, 28, 38) and the component (16, 32, 40) substantially reduces the sound particle velocity along the pipe piece (26). It has the same effect. The ultrasonic standing wave atomizer device according to claim 1, comprising the following features:
The component (16, 32, 40) is a second sonotrode. The ultrasonic standing wave atomizer device according to claim 1, comprising the following features:
The shape of the opposing surfaces (18, 22) of the sonotrode (14, 28, 38) and the component (16, 32, 40) is formed as a hollow cylinder;
The axis of this hollow cylinder is arranged parallel to the axis of the pipe piece (26) in the longitudinal direction. The ultrasonic standing wave atomizer device according to claim 3, comprising the following features:
The hollow cylindrical shape of the end faces (18, 22) is approximately formed by a number of partial surfaces (36) arranged corresponding to the shape. The ultrasonic standing wave atomizer device according to any one of claims 1 to 4, comprising the following features:
The end faces (18, 22) are preferably formed on the sound body (21) of a rectangular sonotrode and on the components (16, 32, 14), respectively. An ultrasonic standing wave atomizer device according to any one of claims 1 to 5, having the following features:
A radius (15) of the hollow cylinder (13) substantially forming the end face (18, 22);
These end faces (18, 22) correspond to the length of the outer surface of the sound body (21) or the side surfaces of the outer surface of said component (16, 32, 40);
This outer surface is perpendicular to the center line of the pipe piece (26). An ultrasonic standing wave atomizer device according to any one of claims 1 to 6, having the following features:
Around said intermediate space, an enclosing element (46) is arranged;
The enclosing element (46) has a gap in the paint spraying direction and substantially prevents the emission of ultrasonic waves in other directions. The ultrasonic standing wave atomizer device according to claim 7, comprising the following features:
The enclosing element (46) is U-shaped. The ultrasonic standing wave atomizer device according to claim 7, comprising the following features:
The pipe piece (26) passes through the enclosing element (46). An ultrasonic standing wave atomizer device according to any one of claims 7 to 9, having the following features:
The gap is selected to be just long enough to allow the spray mist to reach the workpiece to be coated without interruption. An ultrasonic standing wave atomizer device according to any one of claims 7 to 10, comprising:
The distance between the enclosing element (46) and the sonotrode (14, 28, 38) or the component (16, 32, 40) should be such that, under normal operating conditions, contact between them is barely possible. Set smaller. An ultrasonic standing wave atomizer device according to any one of claims 1 to 11, having the following features:
A ring-shaped member (48) is arranged around the paint outlet opening of said pipe piece (26);
The paint outlet opening of the pipe piece (26) is located inside the cylindrical shape defined by the outer peripheral surface of the radially inner ring. An ultrasonic standing wave atomizer device according to any one of claims 1 to 11, having the following features:
A ring segment (56) is disposed near the periphery of the paint outlet opening;
The paint outlet opening is located inside a cylindrical shape defined by a radially inner peripheral surface of the ring segment (56). An ultrasonic standing wave atomizer device according to claim 12 or 13, comprising the following features:
The ring-shaped member (48) or the ring-segmented member (56) has a hydrophobic surface, in particular a surface made of tetrafluoroethylene. An ultrasonic standing wave atomizer device according to any one of claims 12 to 14, comprising:
The ring-shaped member (48) or the ring-shaped segment (56) is configured to be able to blow cleaning air. The ultrasonic standing wave atomizer device according to any one of claims 1 to 15, comprising the following features:
A flow of cleaning air is formed, thereby preventing or reducing wetting of the sonotrode and / or the component. An ultrasonic standing wave atomizer device according to any one of the preceding claims, having the following features:
A directing air flow is created, which can affect the trajectory of the paint spray mist. An ultrasonic standing wave atomizer device according to any one of the preceding claims, having the following features:
A charging device is provided, whereby the paint can be charged electrostatically.

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