WO2003004172A1

WO2003004172A1 - Paint pistol with a compressed air generator

Info

Publication number: WO2003004172A1
Application number: PCT/EP2002/007294
Authority: WO
Inventors: Hermann Rugen
Original assignee: Hermann Rugen
Priority date: 2001-07-03
Filing date: 2002-07-02
Publication date: 2003-01-16

Abstract

The invention relates to a paint pistol (2) having a handle part (8), a compressed air channel (22) with an outlet nozzle (24) and a paint container (4) that is connected to a compressed air channel (22) by means of a paint feed channel (30). In order to improve handling ease of a paint pistol, said paint pistol (2) is equipped with its own compressed air generator that is integrated into the paint pistol. Energy from an accumulator (10) that is also integrated into the paint pistol (2) is supplied to the electric motor (16) of said compressed air generator. The invention also relates to a compressed air generator (12) embodied as a modular component.

Description

Spray gun with compressed air generator

The invention relates to a spray gun with a handle part, a compressed air duct with an outlet nozzle and a paint container, which is connected to the compressed air duct by an ink supply duct, and to a compressed air generator as a modular component.

A wide variety of tools for processing liquid paints by spraying paint particles with compressed air in the direction of the object to be painted are known. The majority of manual or machine-operated spray guns are supplied with air or other gases via appropriate supply devices and lines. The paint liquid is conveyed from a tank attached to the spray gun or a separate feed line into the compressed air duct, where the compressed air flowing through the compressed air duct entrains particles of the paint liquid and forms a finely atomized paint mist through the outlet nozzle. The paint gun is guided so that at least part of the paint mist sticks to the object to be painted.

The compressed air required to generate the paint mist has a working range of 2 to 5 bar for one type of spray gun. The pressure is generated by stationary compressor units and the compressed air is then conveyed through hose lines to the spray gun. Spray guns with such high working pressures have some disadvantages: the generation and provision of the pressure is comparatively energy-intensive, a great deal of effort has to be made to seal the compressed air system, and the high air pressure atomizes the paint liquid to a considerable extent, which leads to that a large proportion of the color flow not on the object to be painted, but undesirably on other places. The amount of air required is 200 to 400 l / min.

Another type of spray gun works on the principle of low pressure painting technology. The pressures required for this are comparatively low, they are overpressures of 0.1 to 0.3 bar. However, in order to be able to transport sufficient paint liquid, the air throughput must be increased, which is then around 500 to 900 l / min. lies. At lower air pressures, the cross-sections in the nozzle area of the spray gun must be larger than with high-pressure technology. The nebulization of the color liquid is less pronounced and the energy requirement is lower. The hose cross-sections for conveying the compressed air are, however, significantly larger in order to be able to convey sufficient air.

Both painting principles suffer from the disadvantage of requiring a continuous air supply via hoses. The hoses attached to the spray guns limit the range of the spray guns, the operator is restricted in handling the spray gun because the inflexible hose impedes rotation, and the operator must be careful not to trip over the hose or the object to be painted with the hose to touch.

In another type of spray gun, a pressure generator with an electric drive is integrated into the spray gun, which does not work with compressed air, but rather presses the paint liquid through a small nozzle and then atomizes it. Because of the considerable energy requirement of the pressure generator, the electric drive must be continuously supplied with electricity via a power cable. The power cable is gradually more flexible than conventional air hoses, but in principle the disadvantages that the air hoses cause also apply to the power cable. In addition, the painting result with this type of spray gun is often unsatisfactory because the paint mist lacks a laminar air flow, which makes it difficult to evenly distribute the paint liquid on the object to be painted.

It is the object of the present invention to provide a spray gun which enables easier handling during painting without having to do without compressed air as a transport medium for the paint liquid. For this, a new technology of a compressed air generator has to be developed that provides sufficient compressed air with compact dimensions.

The problem is solved by installing a compressed air generator in the spray gun, consisting of an air intake duct, an electric motor, a blower driven by it and an air outlet opening into the compressed air duct, and the electric motor being able to derive its electrical power requirement from an accumulator that can be used with the spray gun connected is. A spray gun with compressed air generator and power supply via a supply line instead of an accumulator are also possible according to the invention. The compressed air generator can be designed as a modular component and preferably operate according to the side channel blower principle.

In the case of a spray gun according to the invention, the paint liquid is entrained and atomized by an air flow, which enables uniform paint application. At the same time, the obstructing air hose or the power cable can be dispensed with, which enormously simplifies the handling of the spray gun at work. But even a version with only one power cable connected to the spray gun means that it is considerably easier to use because the power cable is much more flexible than conventional air hoses. At a low energy requirement of the motor, it is sufficient to take the electrical energy from an accumulator which is detachably connected to the spray gun. The term accumulator generally means a power source which can consist of batteries, rechargeable storage cells or other units for the mobile provision of electricity, such as, for example, portable fuel cells. The spray gun is easy to use and can be used anywhere. The energy requirement of the motor can be kept comparatively low if the overpressure is in a range of 0.1 to 0.3 bar in the compressed air duct in relation to the ambient pressure. In addition, the spray gun according to the invention is significantly cheaper than the conventional technology, because the unit of the compressed air generator with electric motor and blower is very small and compact and no hoses or cables are required.

In order to keep the energy requirements of the engine and the construction effort and the weight of the spray gun as low as possible, it is proposed to use a blower that works according to the technical principle of the side channel blower. A side channel blower has a particularly tight delivery rate and therefore requires less drive power to generate the same amount of compressed air as conventional compressors. Overall, using the side channel blower reduces the size of the spray gun and the battery can be smaller or can be operated longer without replacement. The operator can work longer without fatigue and is easier to get to hard-to-reach areas of the object to be painted. A fan that works according to the side channel principle can also produce a good, almost laminar flow, which has a positive effect on the quality of the color distribution. In order to achieve sufficient air delivery performance with sufficient speeds in the air delivery duct with small dimensions of the To achieve the blower, the blower should be operated at speeds of significantly more than 3,000 rpm, for example 10,000 to 25,000 rpm.

Further advantageous embodiments of the invention result from the characterizing features of the subclaims. The invention will now be explained in more detail on the basis of exemplary embodiments. Show it:

1 shows the basic structure of a spray gun,

2 shows a cross section through the basic structure of a compressed air generator,

3 shows a cross section through a compressed air generator which is combined with an ink container,

4 shows an embodiment example with an ergonomically adapted compressed air duct,

5 shows a cross section through a side channel blower,

Fig. 6 shows an example of a fan impeller in a perspective

Side View,

7 is an overall view of a side channel blower,

8 shows a cross section through a spray gun with a compressed air generator in the middle part, Fig. 9 shows a cross section through a spray gun with a compressed air generator in the handle part.

In Figure 1, the spray gun 2 can be seen, which consists of a paint container 4, a middle part 6, a handle part 8 and an accumulator 10. The accumulator 10 can be permanently installed, it is then designed to be rechargeable, or it is detachably connected to the spray gun 2, it can then be quickly replaced with replacement accumulators. The compressed air generator 12 is arranged in the middle part 6 as an installation component. The spray gun 2 is provided with an actuating lever 9 as an actuating element with which the spray strength of the spray gun 2 can be regulated. The actuating signal by actuating the actuating lever 9 can either regulate the speed of the motor and / or fan or change a passage cross section which regulates the passage of compressed air into the compressed air duct, or else regulate the speed and change the passage.

In Figure 2, the basic structure of the compressed air generator 12 is shown in cross section. The intake air is drawn into an air intake duct 18 by a blower 14, which is driven by an electric motor 16. Instead of the air intake duct 18 or in addition to the air intake duct 18, the intake air can also be drawn in by the electric motor 16. This improves the cooling and makes it possible to build the electric motor 16 even smaller. Air filters and / or silencers 20 can be arranged in front of or in the air intake duct 18. The blower 14 takes the air sucked in from the air intake duct 18, compresses it into the compressed air housing arranged in the blower 14 and then conveys the compressed air into the compressed air duct 22. The compressed air duct 22 is provided with an outlet nozzle 24 through which the compressed air escapes from the compressed air duct 22 , The compressed air duct 22 and / or that Compressed air housings have sound-insulating properties if they have a housing thickness that has a sound-absorbing effect, or if additional sound-absorbing materials are built into the housing, or if the inner surface is designed to have a sound-absorbing effect.

The compressed air generator 12 is constructed in such a way that the electric motor 16 is not directly surrounded by an outer wall 26, but rather the suctioned-in air is passed through an intermediate space between the outer wall 26 and the electric motor 16. This design offers various advantages: the intake air cools the electric motor 16 and thereby keeps it at an uncritical operating temperature level. The heated intake air, which is then heated again by the subsequent compression, increases the viscosity of the blown-out paint liquid by the heat, which has a positive effect on the painting result. Finally, the air jacket around the electric motor 16 has a sound-absorbing effect, as a result of which the operating noise of the spray gun 2 is reduced.

The compressed air generator 12 constructed in this way can be constructed as an individual component. It can then be easily installed. It is easily removable for maintenance and repair purposes. For professional painting, it is advantageous to connect the compressed air generator to the spray gun 2 in a detachable manner so that in the event of malfunctions, color changes, etc., one compressed air generator can be removed and quickly replaced with another. The construction of the compressed air generator can be modified, for example, by the compressed air duct 22 being permanently installed in the spray gun 2 and the remaining components being removable as a component. It is also conceivable to use the compressed air generator in a tool system, so that the component of the compressed air generator 12 is operated, for example, together with a cordless screwdriver as a drive or connected to a power supply unit. can be used to inflate air mattresses or tires, to aerate ponds and aquariums, and the like.

In Figure 3, the connection of the paint container 4 to the compressed air duct 22 is shown. The pressure pipe 28 connects the compressed air duct 22 to the paint container 4 and transmits the pressure prevailing in the compressed air duct 22 to the paint container 4. The paint liquid is conveyed through the ink supply duct 30 into the compressed air duct 22. The air stream flowing past the end side of the paint supply channel 30 takes paint droplets with it and exits the spray gun 2 through the outlet nozzle 24. The attachment of the paint container 4 to the underside of the spray gun 2 allows a better overview of the working area in front of the outlet nozzle 24 and of the object to be painted. For a more balanced balance of the spray gun 2, however, it may be more favorable to mount the paint container 4 on top of the spray gun 2. With such an arrangement, depending on the viscosity, the color liquid does not have to be pressurized so that it reaches the compressed air channel 22; When attached above, the paint container 4 then forms a counterweight to the accumulator 10. The outlet nozzle 24 should have a nozzle cross-sectional area of 30 mm ² to 80 mm ² . Given the prevailing pressure conditions and the advantageously low wind speeds, this results in air volume flows emerging from the spray gun 2 during operation, which flow in a range from 0.3 m ³ / min to 0.8 m ³ / min. lie. With these air volume flows, the paint liquid is not atomized too much, but they nevertheless allow the paint liquid to be applied evenly to the object to be painted, because the air flow is very well directed. The compressed air duct 22 is shown in a different form in FIG. The angled shape may be required in order to better adapt the compressed air generator 12 to a favorable shape of the spray gun 2. It is also possible to adapt other components of the compressed air generator 12 to their needs in their respective installation position. It would also be possible to install the electric motor 16 with the blower 14 placed on top in the handle part 8, the blower 14 sucking in the air from the outside without being passed by the electric motor 16, and the compressed air from the blower 14 in the approximately horizontal in the middle part 6 built compressed air duct 22 is guided.

FIG. 5 shows a cross section through a side channel blower as a preferred embodiment for the blower 14. The disk-shaped housing 32 has on the outside an air delivery channel 34 which surrounds the housing 32 in a ring shape. In the exemplary embodiment, the cross section of the air conveying duct 34 is round, but it can also be oval or rectangular, or an intermediate piece is inserted between the semicircular halves. In the air delivery channel 34 there is a fan impeller 36, the fan blades 38 of which take up part of the cross section through the air delivery channel 34. The other part of the cross section is taken up by the side channel 40. Viewed in the direction of rotation, behind the air outlet opening 42 of the side channel blower, an interrupter 44 in the cross section of the side channel 40 is fitted, which fills the cross section and extends with its side facing the blower impeller 36 in a ramp-like manner towards the air flow , In order to keep pressure losses as low as possible, the interrupter 44 with its surface facing the blower impeller 36 should have such a large interrupter angle on the inner radius that at least two vane chambers of the blower impeller 36 are covered by it. The principle of operation of a side channel blower is simply explained: in the space of the blade chambers, the air is carried almost at the peripheral speed of the blower impeller 32. As soon as the air flow in the side channel is less than the air flow carried by the blower impeller, a centrifugal force difference occurs between these two air masses, which results in a compensating flow from the outer regions of the vane chambers into the side channel, a circulation flow. The associated mass exchange between the blade chambers and the side channel causes the energy and momentum transfer from the fan impeller to the side channel flow, which is coupled out at the interrupter. In contrast to radial or axial compressors, the energy transfer from the blades to the air as a fluid leads to an increase in pressure in the circumferential direction. In the Anglo-American language area, the term "peripheral fan" is also common for this functional principle. As turbomachines, they have decisive advantages over the classic displacement machines:

- no sealing components subject to friction are required,

- in principle, a common shaft with the drive motor is sufficient,

- cast wheels can be used,

- multi-flow or multi-stage versions are very easy to implement,

- Side channel blowers have characteristic curves without unstable areas, continuous operation is possible in a large area of the characteristic curve. The only limitation is the maximum load capacity of the drive motor and the maximum permissible temperature of the components. A disadvantage is the higher noise emissions, which can be counteracted by taking appropriate precautions. The further disadvantage of side channel blowers of not being able to build up as high pressure differences as displacement machines does not have a disadvantageous effect in the present application, because too high excess pressure leads to excessive atomization of the ink liquid. According to the invention, the fan 14 should only build up an overpressure of 0.1 to 0.4 bar in the compressed air duct. The air intake opening can be located in the area of the air delivery duct, but also centrally in the housing, which could simplify the installation of silencers and / or intake filters. With a central inflow, part of the kinetic energy could be used to accelerate the development of the circulation flow required for energy transfer.

Instead of a side channel blower, a cell compressor can also be used as the blower, which has a similar application characteristic to the side channel blower in relation to the displacement machines.

FIG. 6 shows a blower impeller 36 of a side channel blower in a perspective side view. The fan impeller has 15 fan blades 38 which are set at an angle of 130 ° in the circumferential direction. With a number of 10 - 20 fan blades 38, a satisfactory efficiency can be achieved. The angle of attack should be in the range of 100 ° to 150 ° so that the air flow can be moved on the one hand, but on the other hand it should not cause any efficiency losses due to excessive turbulence. For use in the spray gun 2, the inner radius 46 should lie in a range between 10 mm and 25 mm, the outer radius 48 in a range between 28 and 45 mm. FIG. 7 shows an overall view of a blower 14 which works on the side-channel blower principle. The disk-shaped housing 32 is round with an annular and semicircular elevation on its top. The air conveying duct 34 is arranged under the annular and semicircular elevation. The air intake opening 50 is shown open, the interrupter 44 is partially visible through the air intake opening 50. The air outlet opening 42 is extended by a compressed air housing 52 which transfers the compressed air generated by the blower 14 into the compressed air duct 22. The compressed air housing 52 can of course have other shapes that match the construction of a respective spray gun 2.

FIG. 8 shows a cross-section of a spray gun 2 in which the compressed air generator 12 is installed in the central part 6. It can be seen in FIG. 9 that the pressure generator 12 is installed in the handle part 8.

Claims

claims

1. spray gun (2) with a handle part (8), a compressed air channel (22) with outlet nozzle (24), a paint container (4), which is connected by a paint supply channel (30) with a compressed air channel (22), characterized that a compressed air generator (12), consisting of an air intake duct (18), an electric motor (16), a blower (14) driven thereby and an air outlet opening (42) opening into the compressed air duct (22), is installed in the spray gun (2) and the electric motor (16) can derive its electrical power requirement from an accumulator (10) which is connected to the spray gun (2).

2. Spray gun (2) with a handle part (8), a compressed air channel (22) with outlet nozzle (24), a paint container (4) which is connected by a paint supply channel (30) to a compressed air channel (22), characterized that a compressed air generator (12) consisting of an air intake duct (18), an electric motor (16), a blower (14) driven by it and an air outlet opening (42) opening into the compressed air duct (22) is installed in the spray gun (2) and the electric motor (16) can derive its electrical power requirement from an electrical supply line.

3. spray gun (2) according to claim 1 or 2, characterized in that the speed of the electric motor (16) and / or the blower (14) via an attached to the spray gun (2) adjusting element (9) is variable.

4. spray gun (2) according to any one of claims 1 to 3, characterized in that the blower (14) is designed according to the principle of side channel machines as a side channel blower, the side channel blower consists of a disc-shaped housing (32) with an outside annular air delivery channel ( 34), a blower impeller (36) which can be driven in rotation with radial or meridional fan blades (38), an air intake opening (50) and an air outlet opening (42), and a cross section of the air delivery duct (34), which is partly a part of the movement path the fan blades (38) and to another part is taken up by the side channel (40), in the cross section of which an interrupter (44) is positioned at least at one point.

5. spray gun (2) according to claim 4, characterized in that the blower impeller (36) at speeds in the range of 10,000 to 25,000 rpm. is operable.

6. spray gun (2) according to one of claims 4 or 5, characterized in that the angle of inclination of the fan blades (38) in the circumferential direction is between 100 ° and 150 °.

7. spray gun (2) according to any one of claims 4 to 6, characterized in that the inner radius (46) of the fan impeller between 10 and 25 mm and the outer radius (48) of the fan impeller (36) between 28 and 45 mm is.

8. spray gun (2) according to one of claims 4 to 7, characterized in that the fan impeller (36) has a number of 10-20 fan blades (38).

9. spray gun (2) according to one of claims 4 to 8, characterized in that the interrupter body (44) on its surface facing the blower impeller (36) has such a large interrupter angle on the inner radius (46) that at least two vane chambers are covered are.

10. spray gun (2) according to one of claims 4 to 9, characterized in that in the spray gun (2) muffler and / or air filter (20) are installed.

11. spray gun (2) according to any one of the preceding claims, characterized in that the compressed air duct (22) and / or the compressed air housing (52) have sound-insulating properties.

12. Spray gun according to claim 1 or 2, characterized in that the blower (14) works on the principle of the cell compressor.

13. Spray gun according to one of the preceding claims, characterized in that the power of the compressed air generator (12) is designed to generate an overpressure of 0.1 to 0.4 bar in the compressed air duct (22) in relation to the ambient pressure.

14. Spray gun according to one of the preceding claims, characterized in that with a diameter of the nozzle opening of the outlet nozzle (24) between 30 mm ² and 80 mm ^2, the air volume flows that emerge during operation of the spray gun (2) through the outlet nozzle (24) , between 0.3 m ³ / min. and 0.8 m ³ / min. be.

15. Spray gun according to one of the preceding claims, characterized in that components of the compressed air generator (12) in the middle part (6) and / or in the handle part (8) are installed.

16. Spray gun according to one of the preceding claims, characterized in that between the electric motor (16) and the outer wall (26) and / or through the electric motor (16) supply air to the fan (14) can be passed.

17. Compressed air generator (12) as a modular component, consisting of an air intake duct (18), an electric motor (16), a blower (14) driven thereby and an air outlet opening (42) opening into the compressed air duct (22).

18. Compressed air generator according to claim 17, characterized in that the blower (14) is designed according to the principle of side channel machines as a side channel blower and the side channel blower consists of a disc-shaped housing (32) with an outer annular air delivery channel (34), a rotatingly driven blower Impeller (36) with radial or meridional fan blades (38), an air intake opening (50) and an air outlet opening (42), and a cross section of the air conveying channel (34) which is partly a part of the path of movement of the fan blades (38) and one another part is occupied by the side channel (40), in the cross section of which an interrupter (44) is positioned at least at one point.

19. The compressed air generator (12) according to claim 17, characterized in that the compressed air generator has one or more of the characterizing features of claims 4 to 9.