JP5336778B2 - Annular pattern spray gun - Google Patents

Description

The present invention relates to a spray gun that atomizes paint ejected by a spray nozzle and prevents paint adhesion of a spray device that forms an annular spray pattern.

An air spray gun for atomizing a paint using compressed air to form a painted surface is widely used in various fields because it can deal with the uniformity of the finished surface, a wide range of objects to be coated, and the paint. In such spray coating, there is a spray gun in which uniform fine particles can be obtained by an annular nozzle capable of spraying in a wider range when the compressed air is made to collide with the paint and sprayed.

This type of spray nozzle is generally provided with an annular paint jet outlet, which ejects compressed air from a concentric annular air outlet, atomizes it by collision with the paint, and places it on the object to be coated in an air stream. To spray. Unlike a spray gun that sprays paint from the center, it has a circumferential outlet, so it can collide with compressed air in a large area, can be atomized finely, and has the advantage of high finished surface quality. ing.

The paint spout can be formed by opening a large number of small spouts around the circumference, or by forming a circumferential slit and spraying it around the gap, and if necessary, a jet that has an angle with the circumferential surface. Some examples are known, such as changing the spray direction by using the outlet. Similarly, an air port for injecting compressed air for atomization is also formed, but structurally it is often a slit, and if necessary, by forming a groove on one surface forming the slit, the ejection direction and amount can be adjusted. It is known to adjust.

Constructing an annular gap with slits is easier than structurally forming a large number of holes circumferentially, and it is easy to adjust the air volume by changing the area of the opening by adjusting the gap of the slit Many of these types of spray nozzles use such slits because it is easy to set the angle spreading in the direction of the central axis by the taper and the fine particles after spraying can be directed forward .

As described above, the paint particles sprayed in an annular shape are often applied to an atomized annular spray pattern by a compressed spray gun, except when the paint particles are applied to an object to be coated around it. The directional component is given to the front by jetting and is directed toward the object to be coated. Therefore, the spray pattern flows so as to wrap around the tip portion of the spray nozzle.

The spray pattern at this time depends on the direction of spray given by the configuration of the spray nozzle, and depending on the coating conditions, it reaches the object to be coated in an annular shape, or is drawn to the center to collect paint particles and gathers into a circular spray pattern Will come to form. In any case, the central tip of the spray nozzle will be placed in the spray.

Japanese Patent Laid-Open No. 5-345152 Japanese Utility Model Publication No. 58-30596 Japanese Patent Publication No. 2-20302

As described above, in the case of a spray nozzle that forms an annular or circular pattern sprayed around, the coating is performed with the tip surrounded by sprayed paint particles, and the paint particles caught in the center are When it adheres, it gradually accumulates and eventually peels to form coarse particles that adhere to the object to be coated and cause poor coating. This kind of paint adhesion is a phenomenon that is disliked by workers because it is not known when it occurs, and it cannot be used after all. In particular, when the size of the spray pattern is set small, adhesion is likely to occur due to entrainment of paint particles, and improvement as a spray gun is required.

An object of the present invention is to improve the adhesion of paint that occurs on the spray nozzle of a spray gun using such an annular spray nozzle, and can be used with confidence even after a long period of use and does not cause poor coating.

A paint nozzle with a large number of openings on the circumference or circumference, a spray nozzle with a concentric annular atomizing air port behind the paint outlet, and a spray axis in front of the spray nozzle. It is assumed that a spray head having a cylindrical shape substantially the same in diameter and having a conical or spherical tip is provided, and the length of the spray head extends forward from the outer diameter. Further, the spray head may be opened with the tip thereof being cylindrical.

The spray head is attachable to and detachable from the spray nozzle, or is provided with a passage that connects an air passage that is supplied to the annular atomizing air port and a discharge port that opens to the front end side from the inside of the spray head so that air flows. It can also be configured.

According to the present invention, the paint sprayed in a ring shape is sprayed around by the compressed air sprayed in the ring shape, and the spray particle group heading forward is centered by the spray head extending forward in which the center part is formed. Without being caught by the spray head and by the accompanying airflow formed between the spray head and the particle group, it is sent forward without adhering to the outer surface of the spray head. For this reason, adhesion of the paint to the spray nozzle is prevented, and suitable coating can be continued even for long-time use.

Therefore, in order to prevent coating defects from scattering of coarse paint particles caused by adhesion, efficient and high-quality coating is achieved by preventing the burden on workers who periodically suspend work and cleaning and reducing productivity. The work can be continued, and the effect can be improved particularly in automatic painting.

In addition, if the spray head can be replaced, even if the coating conditions change and the state of adhesion changes due to the flow of spray particles, it can be replaced with a spray head that can obtain the optimal situation. There is no need to prepare a spray nozzle, and it is possible to cope with the minimum. Even if the selection is not appropriate and adhesion is recognized, it can be quickly dealt with by removing and replacing only the spray head, and it is not necessary to replace the spray nozzle when cleaning.

FIG. 1 shows the overall structure of a spray gun according to an embodiment of the present invention. The spray gun is an example of an automatic gun, and an atomizing device 3 is attached to the front end side of the main body 1. The compressed air for atomization opens the air valve 5 by the operation of the piston 4, and is sent from the air passage 6 to the atomizing device 3 at the tip through the passage 13. The needle valve 23 is retracted by the retreat of the air valve 5, and the paint nozzle 31 provided at the tip is opened to eject the paint. The detailed structure for operating this type of automatic spray gun is well known and is not intended to limit the present invention, and therefore will not be described in detail.

FIG. 2 partially enlarges the atomizing device 3 at the tip. The atomizing device 3 has a paint nozzle 31 attached to the tip of the paint pipe 21 at the center and an air cap 32 provided at the tip of the air pipe 22 on the outside thereof concentrically. As described above, the needle valve 23 whose tip abuts and separates is provided at the inner center of the paint nozzle, and the outlet side is screwed into the paint outlet passage 33 opened in the boss portion 34 of the deflection plate 35. A large number of outlets 36 that radially open from the paint outlet passage 33 toward the outer peripheral surface of the boss portion 34 are provided, and the paint discharged from the paint nozzle 31 is ejected radially from the outlet 36. The packing 37 is attached to prevent leakage from the paint outlet passage 33.

The outer periphery of the boss portion where the jet port 36 opens forms a tapered surface 38 that terminates immediately before the opening end of the jet port 36, and the inner tapered surface formed along the tapered surface 38 at the inner peripheral front end of the air cap 32. An air gap 40 is formed between the air nozzle 40 and the air nozzle 40. From the air nozzle 40 constituted by the gap between both tapered surfaces, an air flow that is annular and spreads forward is ejected, and the gap is adjusted by the position where the air pipe 22 integrated with the air cap 32 is fixed. . This adjustment position is not limited to the above, and it can be adjusted by the screwing position of the deflector plate 35 and the paint nozzle 31. For example, the existing design technique can be used freely.

The paint that has come out radially from the jet port 36 is atomized by the compressed air jetted from the center of the rear part thereof, and sprayed around the taper surface 42 of the deflection plate 35 toward the outer periphery. At this time, the spray flow gradually flows forward while spreading outward, and eventually, the directional component toward the front is mainly sprayed toward the object to be coated. The spray flow varies depending on the injection angle of the compressed air as well as the shape angle of the deflecting plate 35, and the pattern shape is determined by this.

A front spray head 41 is detachably provided on the deflection plate 35. The example of FIG. 2 has a shape that extends in a cylindrical shape from the outer diameter of the deflection plate 35 and converges to a conical shape at the tip. The entire length including the cylindrical portion 43 is larger than the outer diameter. As a result, an accompanying airflow is generated in the cylindrical portion, and coating adhesion to the spray head 41 surface is prevented.

In the example of FIG. 3, the tip is made spherical, but the cylindrical portion 43 is made longer due to the winding state of the tip. Further, in FIG. 4, the tip is cylindrical, and the tip is opened. In this case, since the length of the cylindrical portion is relatively large, the speed of the spray flow is slow due to air resistance, and the coating particles themselves are also dispersed, so there is no entrainment due to the spray flow, and the opening 44 Adhesion of the paint is prevented by the airflow in which the air sucked from the center flows out from the outer peripheral side.

As another example, as shown in FIG. 4, an air passage 45 leading from the deflecting plate serving as a passage for atomizing air to the opening is formed, and a slight amount of air is allowed to flow from the tip of the opening 44 to reliably Paint adhesion can also be prevented. In the example shown in the figure, the discharge port is also used because of the shape of the opening at the front end. However, when the front end is blocked as shown in FIGS. 2 and 3, it can be dealt with by appropriately opening the discharge port ejecting forward.

Sectional drawing which shows the whole structure of the spray gun using one Example of this invention. Sectional drawing which expanded and displayed the part of the atomization apparatus provided in the spray gun main body front-end | tip part of FIG. Sectional drawing which shows the Example of another atomization apparatus. Sectional drawing which shows the Example of another atomization apparatus.

Explanation of symbols

1 Gun body 3 Atomizer 4 Piston 5 Air valve 6 Air passage 13 Passage 21 Paint pipe 22 Air pipe 23 Needle valve 31 Paint nozzle 32 Air cap 33 Paint outlet passage 34 Boss part 35 Deflection plate 36 Spout 41 Spray head 43 Cylinder Part 44 opening 45 air passage

Claims (4)

A paint nozzle having a large number of openings on the ring or circumference, a spray nozzle having a concentric annular atomizing air port behind the paint nozzle, and an outer periphery that blocks the spray flow in front of the spray nozzle in an annular pattern atomizing spray gun having a deflector plate for diffusing the direction, a cylindrical substantially the same outer diameter as the spray nozzle around the spray axis in front of the deflector plate, the tip is a spray head conical or spherical provided,該噴Kiriatama cyclic pattern atomizing spray gun, characterized in that to prevent the paint from adhering to and if extended forwardly longer than the outer diameter the spray head. A spray nozzle provided with a large number of openings on the circumference or the circumference, a spray nozzle provided with a concentric annular atomizing air port behind the paint spray outlet, and a spray centered on the spray axis in front of the spray nozzle An annular pattern spray spray gun having a cylindrical spray head having an outer diameter substantially the same as that of a nozzle and provided with a hollow spray head having an open end, and the spray head extends forward longer than the outer diameter. The annular pattern spray spray gun according to claim 1 or 2, wherein the spray head is detachable from a spray nozzle. The annular pattern spray spray gun according to claim 1 or 2, further comprising a passage connecting an air passage supplied to the annular atomizing air port and a discharge port opening from the inside of the spray head to the tip side.

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