EP2576079B1 - Nozzle head for a spray gun - Google Patents

Description

The invention relates to a nozzle head for a spray device according to the preamble of claim 1.

Such nozzle heads are common to spray devices for hydrostatic, pneumatic or combined hydrostatic and pneumatic atomization of paint, paint, glue or other liquid substances, in particular paint spray guns.

In the nozzle heads of such spraying devices, the air ring nozzle has the function of allowing the compressed air supplied to the device to emerge as an air jet of high energy, which sucks material from another, central nozzle, atomized and forms a material-laden spray jet. Horned air nozzles are usually directed obliquely and in the same direction to the outflow direction on the spray jet in laterally arranged, in the direction of spray jet pointing horns of the nozzle head, so that the air jets emerging from these nozzles can deform or shape the spray jet. As a result of the lateral deformation / shaping, a more or less large flat jet or a flat and omnidirectional jet is produced as a function of the flow energy (amount of air, air pressure, flow velocity, etc.).

In order to achieve an optimum result, the spray jet must be adjusted for the beam width, material distribution, material type and drop size, among other things. The adaptation is carried out depending on the physical boundary conditions (input air pressure, air volume, etc.) essentially by constructive adjustment of the mouth of the central air ring nozzle and the Hornluftdüsen. For sufficiently homogeneous spray steels usually one, two, three or more horn air nozzles are used per horn, which interact with the central mouth of the central nozzle. From practice paint spray guns with one, two or more Hornluftdüsen are known, which ensure sufficient beam shaping and atomization on the criteria of mutual distance, diameter, angle and distance to the paint nozzle mouth, and their number. The Hornluftdüsen are provided in an air cap attached to the spray gun body, is usually screwed by means of fastening rings. The central air nozzle can also be screwed directly onto the paint nozzle or on the paint spray gun body, clipped or be otherwise attached. Such a nozzle head is known for example from German Utility Model G 90 01 265.8. The color nozzle openings and the Hornluftdüsenöffnungen are designed as commonly used as round holes.

In practice, the diameters of the Hornfuftdüsen be made different sizes depending on the inlet pressure and the individually desired shape of the spray jet. The effect of the individual horn air nozzles depends on the inlet pressure. At higher input pressures, the beam may split. If the input pressures are too low, unwanted coarsening with small beam width may occur. There is also a large dependence of material throughput and other material properties (e.g., viscosity, rheology, etc.), inlet pressure, and horn air nozzle placement. Occasionally, with the use of one or more smaller horn air nozzles or unfavorable bore angles, problems arise with back mist on the mouth surfaces of the nozzles due to the suction effect at smaller nozzle or bore diameters.

A modified version of a spray gun with a nozzle head shows the patent US 5,165,605 wherein the nozzle head laterally protruding horns with slot-shaped Hornauslassöffnungen describes.

In general, small control openings or Hilfszerstäuberöffnungen are additionally arranged around the central nozzle, which contribute to the beam shaping and atomization. In order to convert the jet preformed from the cylindrical tube of the central air nozzle opening into another shape, for example to convert an omnidirectional jet into a flat jet, high amounts of energy from the jet bores and horn bores are necessary, which lead to high energy losses and limit the beam shaping.

A major drawback of this method of beam shaping is that much of the energy used for beam forming and post-atomization already evaporates through the tight holes and multiple outlets to the ambient air (large shear surfaces at the surface in connection with large speed differences).

Often modified nozzle heads with possibly different spraying parameters and geometries have to be used for slightly different color or paint materials in order to achieve a perfect spray pattern and thus the desired color, lacquer or to get other material order result. The object of the invention is to improve a nozzle head so that the flow energy of the compressed air can be optimally implemented in Strahiformung, flow rate and thus in Zerstäubungsarbeit.

This object is achieved by a nozzle head having the features of claim 1. By shaping the central jet with the aid of at least one non-cylindrical horn air nozzle, it is also possible to save considerable amounts of energy for beam shaping.

The invention is based on the fact that in cylindrical nozzles the necessary adaptation to the individual requirements is possible only by variations in the diameter dimensions, the length and the inclination of the cylindrical bores, their mutual distance and the distance to the other nozzle openings. Non-cylindrical nozzles can be more easily optimized in terms of flow and adapted to the individual task.

It goes without saying that while the inner shape, in particular the mouth of the nozzle should be non-cylindrical. The outer shape of the nozzles is usually negligible for beam forming.

Advantageous embodiments of the invention are specified in the remaining claims.

In a development of the invention, a variable design of the control bores is proposed in order to achieve efficient beam shaping.

The same applies to the shaping of the flow areas of the air nozzle. As a result, the round jet can be preformed by a special shaping so that less horn air is required for the shaping of the broad jet and any desired beam shapes can be achieved.

In particular, elliptical or at least approximately slot-shaped nozzles are recommended in cross-section.

By an expanding in the direction of the spray jet nozzle opening of the sputtering process can be further improved.

Also, grooves, slats, air vanes or the like may be provided for air conduction in the nozzle openings.

The non-cylindrical nozzles can be made in metal parts by machining. The non-cylindrical nozzles made of plastic, in particular of an injection-moldable plastic, can be produced in a particularly simple manner. It is also possible to use such nozzles in plastic inserts and fasten in metal nozzle heads.

Also, by the combination of cylindrical, conical and other non-cylindrical nozzle openings further advantageous effects can be achieved.

Further advantageous details are shown in the figures explained below.

• Fig. 1 einen Schnitt durch ein erstes Beispiel eines Düsenkopfes,
• Fig. 2 eine Draufsicht auf einen Teilbereich des Düsenkopfes nach Fig. 1, der eine nicht beanspruchte Variante zeigt,
• Fig. 3 eine nicht beanspruchte Variante von Fig. 2,
• Fig. 4 bis 8 und 11 bis 14 jeweils eine Draufsicht auf diverse Varianten eines Teilbereichs eines Düsenkopfes,
• Fig. 9 und 10 jeweils eine Schnittansicht eines Düsenkopfes,
  und
• Fig. 15 eine Explosionsdarstellung eines weiteren Düsenkopfes .

Showing:

• Fig. 1 a section through a first example of a nozzle head,
• Fig. 2 a plan view of a portion of the nozzle head according to Fig. 1 which shows an unclaimed variant,
• Fig. 3 an unclaimed variant of Fig. 2 .
• Fig. 4 to 8 and 11 to 14 each a plan view of various variants of a portion of a nozzle head,
• Fig. 9 and 10 each a sectional view of a nozzle head,
  and
• Fig. 15 an exploded view of another nozzle head.

The in Fig. 1 and 2 Exemplary nozzle head for a paint spray gun has a paint nozzle body 1 with a substantially cylindrical ink channel 2, which opens centrally in a paint nozzle 3. In the paint nozzle 3, a hollow paint needle 4 is inserted. The paint nozzle 3 is surrounded by an air ring nozzle 5, the air can be supplied via channels 6. On the gun body, an air cap 7 by means of a ring 203, which is commonly referred to as air nozzle ring, screwed. The air cap 7 could also be otherwise attached to the gun body. In the present embodiment, the air cap 7 is injection-molded from a plastic. It has an annular portion 8 which fits fittingly on the gun body. The annular section 8 is followed by a substantially flat cover plate 9. In a so-called mouth region, the cover plate 9 has an over this flat region 9 projecting annular elevation 10, in which an opening 11 is recessed centrally. The opening 11, when the paint nozzle 3 is mounted, extends around it and thus around the air ring nozzle 5. In the cover plate 9 are provided laterally the opening 11 at several points continuous control nozzles or control openings 12. The control nozzle openings 12 are aligned at an angle of about 20 degrees to the spray jet direction 100 out. At two opposite points, the air cap 7 has a respective horn 13 or 14, which extends forward in the spray direction 100. In the present embodiment, the horns 13, 14 are formed as rectangular in cross section, closed at the top body. Each horn 13, 14 has two jet air nozzles 15, 16 or 17, 18 which are arranged one behind the other in the direction of spray jet 100 and extend through the inner wall 19 of the horns 13, 14. The Hornluftdüsen 15,16,17,18 are aligned obliquely in the direction of the spray jet 100. In the present case, the two Hornluftdüsen 15, 16 and 17, 18 of each horn 13 and 14 are substantially parallel to each other at an angle 101 of about 140 degrees to the spray direction 100. The Hornluftdüsen 15, 16 but could also at an angle to each other or against each other. They can be supplied with compressed air in each case via an air duct 20 or 21 extending in the longitudinal direction through the horn 13 or 14. The ring air jet emerging with high energy from the air ring nozzle 5 sucks the paint out of the paint nozzle 3, forming an omnidirectional jet which flows off in the spray jet direction 100. The horn air jets emerging from the horn air nozzles 15, 16 or 17, 18 are directed onto the round jet and flow obliquely and in the same direction to the spray jet direction 100 and deform the round jet to the desired broad jet.

The Hornluftdüsen 15, 16 and 17, 18 are fluidically optimized so that the circular beam undergoes a homogeneous beam shaping and the desired beam width is achieved without splitting the spray jet. As Fig. 2 shows a not claimed embodiment, both Hornluftdüsen 17, 18 of the horn 14 are elliptical in cross section and the same big educated. In the present embodiment, the narrow curves of the ellipses are up or down. However, the ellipses could also be arranged transversely to the longitudinal extension of the horn 14 or 13. Combinations of such ellipses are also possible. This special design of the Hornluftdüsen 17, 18 could be easily realized by injection molding the air cap 7. It is not absolutely necessary to provide a separate air cap 7; the nozzle head 1 could also be designed differently (in one piece). Essential in the context of the invention are the non-cylindrical nozzles in the nozzle head.

In the present example, the paint needle 4 is hollow and has a cylindrical opening 4a along its longitudinal axis, through which a vacuum or an overpressure in the spray jet can be generated. In a particular variant, a further paint component is injected into the spray jet via the hollow needle 4. For this purpose, the inlet opening of the needle 4 is connected to corresponding material-containing devices. In a particular embodiment, the opening 4a may be non-cylindrical, e.g. be oval in cross section or in any other non-cylindrical shape.

The opening 4a may be connected to compressed air or vacuum.

On the other hand, the color needle 4 could not be hollow, but formed of solid body. The needle 4 is advantageously always designed so that its outer shape at the sealing point or contact surface on the paint nozzle 3 corresponds to the inner shape of this nozzle, so that sealing pairings are achieved.

In the unclaimed variant after Fig. 3 For example, the horn-air nozzle 17 coming first in the spray-jet direction 100 is elliptical in cross-section, while the horn-air nozzle 18a coming thereafter is square in cross-section. A rectangular shape is also possible. The Hornluftdüse 18 a is smaller here than the Hornluftdüse 17. In this embodiment, no control openings are present. But they could also be provided here. The same applies to the embodiments described below.

In the unclaimed example Fig. 4 an air cap 7 is indicated for a nozzle head, in which only a single Hornluftdüse 17a per horn is provided. This Hornluftdüse 17a is tear-shaped ovaf formed, wherein in plan view of the inner wall 19 of the horn 14, the greater rounding of the oval in the upper region of the horn 14 is arranged.

At the in Fig. 5 illustrated unclaimed variant is also provided only a single Hornluftdüse 17b per horn. Here, the shape of the Hornluftdüse 17 b is designed such that in plan view of the inner wall 19 of the horn 14 about the outline of the number 8 is visible.

In Fig. 6 is a similar, unclaimed variant as in Fig. 5 shown. In the air cap 7, the Hornluftdüse 17 b after Fig. 5 is here quasi split longitudinally to a two-part Hornluftdüse 17c. The two parts of the Hornluftdüse 17c are approximately crescent-shaped. In the illustrated embodiment, the curves are directed outwards. A reverse arrangement is also possible. It is also possible to align the curves of the crescents up or down

In the unclaimed variant after Fig. 6a three horn air nozzles 18b1, 18b2, 18b3 rectangular in cross section are provided in the horn 14 of the air cap 7.

The Hornluftdüsen described so far have everywhere the same internal dimension in the longitudinal direction. But it can also be used Hornluftdüsen that expand or rejuvenate in the longitudinal direction.

Fig. 7 shows an unclaimed variant in which an elliptical horn-shaped nozzle 17d in plan view widening in the longitudinal direction through the inner wall 19 of the horn 14 upwards or in the longitudinal direction. The flow surface 22 of the Hornluftdüse 17d is smooth.

The flow surface 22 of the Hornluftdüse 17 d or another Hornluftdüse could also be wavy, knobbed, grooved, spiral or otherwise designed.

In the unclaimed variant after Fig. 8 At the air cap 7 is the same horn air nozzle 17a as in FIG Fig. 4 intended. Here, however, the Hornluftdüse 17 a has not been made together with the air cap 7, but recessed as a continuous opening of a plastic body 23 which is inserted into a through hole in the inner wall 19 of the horn 14 accurately, in particular clipped. In the present example, the insert is rectangular in shape - like the opening in the inner wall 19 of the horn 14. The insert and opening for the horn air nozzle 17a or another horn air nozzle may, of course, be designed differently; for the Function of the exemplary nozzle head these details do not play a major role. Such shaped openings for receiving nozzles can be easily manufactured not only in air caps made of plastic, but also in metal air caps such as steel (eg manganese steel).

The insert 23 could also be glued into the opening in the side wall 19 of the horn 14.

In the example below Fig. 9 is in the upper half a variant of Fig. 1 shown; the same components are provided with the same reference numerals. In deviation from Fig. 1 Here, the two Hornluftdüsen 15, 16 of the horn 13 at different angles to the spray jet direction 100. The angle 102 at the Hornluftdüse 15 is about 130 degrees, while the angle 103 in the Hornluftdüse 16 is about 120 degrees.

Fig. 9 shows in the lower half of the sectional view a variant of a portion of the variant according to Fig. 4 , Here it can be clearly seen that the flow surface 22 of the Hornluftdüse 17 a in the vertical extent of the Hornluftdüse 17 a and in the spray jet 100 is formed smooth.

The unclaimed example after Fig. 10 shows a variant of Fig. 8 and Fig. 4 , Here it can be clearly seen that the flow surface 22 of the Hornluftdüse 17a in the vertical extent of this Hornluftdüse 17a may also be formed transversely corrugated and may have a plurality of flow-leading grooves 24 for the horn air. In another configuration, the grooves 24 may be configured as longitudinal grooves. Furthermore, control openings or control nozzle openings 12, 12 a are also provided here. The control nozzle openings 12, 12 a are aligned at an angle to the spray jet direction 100 out. Some control openings or control nozzle openings 12 a, which are provided in the cover plate 9 of the air cap 7, not cylindrical as usual, but designed with a 100 in the spray jet direction flared diameter. In plan view, the control nozzle openings 12a are designed approximately crescent-shaped, as Fig. 11 shows. The inner rounding of each crescent 12 points in this case to the air ring nozzle 5 or to the ink nozzle opening 3. One, two or more control nozzle openings per side can be made in any desired cross sections; the invention is not limited to the number of control nozzle openings. In the present example, four control nozzle openings 12 and 12 a are provided, which are provided in pairs in areas of the cover plate 9 of the air nozzle 7, which are adjacent to the horns 12, 13. In each case, a cylindrical control nozzle opening 12 is adjacent to a non-cylindrical Control nozzle opening 12a. However, it is also possible to provide only non-cylindrical or only cylindrical control nozzle openings.

Instead of the transverse grooves 24 or longitudinal grooves and lamellae, knobs or the like could be provided.

In the unclaimed variant after Fig. 12 Instead of four control openings only two control openings 12b are provided, which are formed even more irregular than in the example described above. They have namely in plan view or in the outline approximately the shape of a trifoliate cloverleaf. The two control openings 12b are provided next to the horns 13, 14 on the cover plate 9 of the air cap 7 next to the paint nozzle 3 and the air ring nozzle 5.

With the above-described cross-sectional shapes of the Hornluftdüsen special, aerodynamically optimized channels for the horn air are created. Of course, other cross-sectional shapes and combinations thereof are possible.

In Fig. 13 a variant of an air cap 7 is shown, in which the around the paint nozzle 3 extending around Luftringdüse is not designed as usual cylindrical. The air ring nozzle 5a is here approximately hexagonal in plan view with two peaks 26, 27 formed. The tips 26, 27 are remote from the horns 13, 14. In another embodiment, the tips 26, 27 could also be facing the horns 13, 14.

Fig. 14 shows another, in plan view strictly oval-shaped Luftringdüse 5b in combination with a similarly shaped paint nozzle 3a on an air cap 7 of a nozzle head. 1

In the two last-described variants, the round jet is preformed by the special shaping so that less horn air is required for the shaping of the broad jet than usual.

Other configurations of the nozzle head with a different air cap or without air cap are possible; essential for the purposes of the invention are the non-cylindrical openings in the nozzle head.

The in Fig. 15 illustrated nozzle head 1a belongs to a high-pressure-fed special gun, which is ideal for processing large amounts of high-viscosity materials, because they are with supporting air atomization works. The nozzle head 1a has a so-called air nozzle 200 and a so-called pre-nozzle 201, which engages via a header 202 in the air nozzle 200. These components can be screwed onto the body of the spray gun, not shown, via a so-called air nozzle ring 203. All air or material-carrying openings or nozzles are usually designed cylindrical in such spray guns. From the central nozzle 3b, the material emerges in the form of a flat jet and is then shaped into an omnidirectional jet. It is proposed to design at least one of the openings 300a, 300b or air or material-carrying nozzles with non-cylindrical, in particular the Hornluftdüsen 300a. This also special effects can be achieved here.

Any combinations of nozzle variants described are of course possible and can lead to particularly advantageous spattering results.

All combinations of cylindrical and non-cylindrical nozzles according to the main claim are conceivable depending on the desired work result and fall under the present invention.

Of course, the invention is not limited to the previously described nozzle heads. It can also be used with advantage in other nozzle heads.

The proposed non-cylindrical nozzles can of course be particularly easy to produce in nozzle heads or parts of nozzle heads, which are made of plastic, in particular injection-molded. In the case of nozzle heads made wholly or partly of metal (usually stainless steel), non-cylindrical nozzles can be realized by means of lost-wax casting or by means of inserts.

In further embodiments, the air nozzle / air ring nozzle can also be plugged, clipped, screwed or otherwise mounted or attached directly to the paint nozzle. The air nozzle and the paint nozzle can also be made in one piece.

The entire nozzle device could be connected directly to a gun body with or without additional support means.

In a further embodiment, the nozzle device is connected directly to the compressed air network or a material supply.

In a further embodiment, the nozzle device can also represent a part of the air or material supply.

Also, the outer shape of the nozzle device may have any geometric shapes in the circumferential direction; In a particular embodiment, the entire spray device may additionally have any desired geometric shapes.

The openings for beam shaping and the Hornluftdüsen or -auslassöffnungen need not necessarily be provided in projecting horns, but can be arranged for example in the plate 9, side elevations, tubes or in a circumferential ring around the plate.

The number of openings in the horns as well as for beam shaping is basically arbitrary; several openings can also be arranged in segments in, for example, opposing areas (90 degrees, 45 degrees, 30 degrees .....). It can be achieved by individual openings, several or many openings special beam shapes

By the described and other conceivable aerodynamically optimized nozzle openings, the energy of the compressed air can be optimally utilized, the jet formed better and the atomization can be improved. As a result, in addition to finer droplets, the droplet distribution in the jet can also be improved and a more uniform droplet distribution center can be produced. Likewise, the reduction of the beam dependence can be achieved by other parameters, e.g. Inlet pressure, material viscosity and manufacturing tolerances and a volume reduction by reducing the exit velocity and reducing the compressed air requirement.

Claims (14)

1. Nozzle head for a spraying apparatus, having a central material nozzle, having an air ring nozzle surrounding said material nozzle, and having at least two laterally projecting horns, into each of which at least one horn air nozzle is incorporated, wherein at least one horn air nozzle (15, 16, 17, 17a, 17b, 17c, 18, 18a, 18b1, 18b2, 18b3, 300a) has a non-cylindrical shape, characterized in that the air ring nozzle (5a, 5b) has a non-cylindrical shape.
2. Nozzle head according to Claim 1, characterized in that an air ring nozzle having a non-cylindrical shape is combined with at least one horn air nozzle having a cylindrical shape.
3. Nozzle head according to either of the preceding claims, characterized in that, beside the air ring nozzle (5), at least one control opening (12a, 12b) is provided, which having a non-cylindrical shape.
4. Nozzle head according to one of the preceding claims, characterized in that at least one nozzle (17a) is connected via an insert (23) to the nozzle head (1) respectively to a component (7) connected therewith, in particular with the air cap of a paint spray gun.
5. Nozzle head according to one of the preceding claims, characterized in that at least one of the nozzles (12a, 12b, 17, 17a, 17b, 17c, 18a, 18b1, 18b2, 18b3) is of elliptical, drop-shaped oval or approximately half moon-shaped form in cross section, has approximately the shape of a three-leaf clover or a rectangle, in particular a square, or resembles the number 8 in cross section or outline.
6. Nozzle head according to one of the preceding claims, characterized in that the flow surface (22) of at least one of the nozzles (17d) is undulated, burled, ribbed or spirally or has another shape.
7. Nozzle head according to Claim 6, characterized in that at least one of the nozzles (17a) has at least one flow-guiding groove (24), in particular a longitudinal groove.
8. Nozzle head according to one of the preceding claims, characterized in that at least one horn (13, 14) has only a single horn air nozzle (17a, 17b), two horn air nozzles (15, 16, 17, 17c, 18, 18a) or three horn air nozzles (18b1, 18b2, 18b3).
9. Nozzle head according to one of the preceding claims, characterized in that the inner dimension of the nozzles (12a) widens or narrows in the longitudinal direction.
10. Nozzle head according to one of the preceding claims, characterized in that a material-guiding needle, which is formed as a solid body or as a hollow needle (4) with a material-guiding opening (4a), is provided.
11. Nozzle head according to Claim 10, characterized in that the opening (4a) in the hollow needle (4) has a non-cylindrical shape.
12. Nozzle head according to one of the preceding claims, characterized in that the nozzle head (1) is at least regionally produced from plastic, in particular injection-moulded from plastic.
13. Nozzle head according to Claim 12, characterized in that a nozzle-guiding insert (23) in the nozzle head (1) is produced from plastic, and the nozzle head is otherwise produced from metal, in particular from steel.
14. Nozzle head according to one of the preceding claims, characterized in that it can be connected directly, or via a support device, to a body of a pneumatic or hydrostatic or combined pneumatic/hydrostatic spray gun.

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