JPS635148B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spray nozzle suitable for atomizing and applying paint using compressed air.

Generally speaking, the two methods of spraying to obtain the necessary atomized particles and spray pattern are the air spray method, in which compressed air collides with and mixes the paint stream, and the other is the air spray method, in which the paint is applied using a high hydrostatic pressure using a small oval orifice. There is an airless spray method that ejects water. In this case, the former air spray method requires a high-pressure paint pump and the orifice must be changed depending on the coating conditions.Compared to the airless spray method, the orifice must be changed depending on the coating conditions. Since it is possible to obtain a pattern and to obtain fine particles, it is widely used as a general-purpose coating device, despite the disadvantages of using a relatively large amount of compressed air and causing a large amount of spray particles to scatter.

In view of the above circumstances, the present invention provides a spray gun that can achieve efficient atomization using less compressed air or lower compressed air pressure, in other words, with less energy.

That is, the present invention has improved the efficiency of atomization, and the first feature is that when the paint is ejected, the liquid flow collides with the liquid to form a flat flow, which increases the contact area with compressed air that is collided and mixed from the surroundings. , to prepare for easy pattern formation. The second feature is that a pattern is formed by spraying angular air onto a group of paint particles that have already been atomized into flat shapes from positions opposite to a substantially flat surface.

Hereinafter, the present invention will be explained with reference to drawings of embodiments.

1 is a paint nozzle provided at the tip of a needle valve 3 placed in the center of the gun body 2, and the tip of the paint nozzle 1 is connected to a central passage 1a as shown in FIGS. 3 to 5.
Two branched paint passages 1b, 1b are formed, and two paint spouts 4, 4 are opened at the outlet end of each branched passage 1b, 1b. That is, two paint ejection ports 4, 4 are formed that are equally spaced apart from each other with respect to the central axis x of the paint nozzle 1 and open at a constant spray angle a so that the ejected paint crosses and collides on the front central axis x. has been done. Further, a central air hole 7 consisting of an annular slit is formed between the outer periphery of the tip of the paint nozzle 1 and a center hole 6 of an air cap 5 disposed on the outside thereof. In addition to the central hole 6, this air cap 5 is provided with at least one pair of square air holes 8 that cross and collide on the axis of the paint nozzle 1 and in front of the intersection position of the opposing paint jet ports 4. Therefore, it is desirable that the air passage 9 to the center hole 6 and the air passage 10 to the corner air hole 8 be provided separately so that the amount of air in each can be changed. In general, the air passing through the air valve 11 of the gun body 2 is controlled by the pattern control valve 12 so that one side of the air enters the central air passage 9 via the central annular air passage 13 and flows toward the central air hole 7; The amount of air is adjusted by the pattern control valve 12, and the compressed air is divided into flows passing through the square air passage 14 and heading towards the square air hole 8 at the tip of the air cap 5, and the compressed air is blown out from each air hole.
It is configured to form a spray pattern suitable for painting. 15 indicates an air cap mounting cover. The rest of the configuration is the same as that of a known spray gun, so a description thereof will be omitted.

Next, to explain the operation, first, paint is supplied into the paint nozzle 1 via the paint nipple 16 of the gun body 2 from a separately provided pressure feeding device (not shown).
The tip of the needle valve 3 contacts and separates from a sheet 17 formed within the paint nozzle 1, thereby controlling the spraying of paint.

The supply of compressed air to the air cap 5 is controlled by an air valve 11. Generally, the air valve 11 is opened by pulling the trigger 18, and the compressed air introduced from the air inlet 19 is fed into the gun body 2. The air is supplied through the air passage 20 to the square air hole 8 of the air cap 5 at the tip of the gun, and the needle valve 3 is connected to the seat 17.
By moving further away and retreating, the paint is ejected from the two opposing paint ejection ports 4, 4 of the paint nozzle 1. The paint ejected from these two opposing paint ejection ports 4, 4 collides crosswise on the central axis x of the paint nozzle 1, and is ejected forward as a flat film-like flow. At the same time as the paint is jetted, compressed air is jetted from the annular central air hole 7 on the outside of the paint nozzle 1, so that the paint jetted as a flat film-like flow becomes fine particles as atomized particle groups with a slightly flat cross section. and sprayed.

Furthermore, the paint is finally sprayed onto the atomized particles by the square air ejected from the square air holes 8, 8 at the tip of the air cap 5 arranged perpendicularly to the substantially flat surface. The spray is formed into the desired spray pattern with fine particles.

The paint flow ejected as described above has a larger surface area than a conventional single-hole nozzle even at the same flow rate, and has a directionality that spreads greatly due to collision, and the surrounding high-speed airflow causes fine particles to form. Highly efficient atomization can be achieved with the same air energy. Furthermore, for pattern formation, compressed air is collided with both sides of the atomized particle group, which has already become flat, making it possible to easily form a pattern.
That is, compared to the conventional method of atomizing paint by airflow in the same direction as the flow of paint having a circular cross section, in the present invention, the paint is jetted across the airflow by collision, so the atomization efficiency is better. In addition, when applying airflow to a group of particles with a circular cross section as in the past, the required oval pattern inevitably becomes unstable, and if auxiliary air holes are provided to stabilize this, the amount of air used will further increase. As a result, this issue was also resolved.

As described above, according to the present invention, desired atomization can be obtained with a smaller amount of air, and a pattern suitable for a spray gun can be formed. In addition, the fine particles of paint advance toward the object to be coated at a moderate and averaged speed, and paint film defects such as scattering due to rebound and unevenness of the painted surface are also improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal side view of the entire spray gun, FIG. 2 is a longitudinal side view of the tip of the spray gun, and FIG. 3 is an enlarged cross-section showing the main parts of the paint nozzle. FIG. 4 is a front view of the same, and FIG. 5 is an end view taken along the line shown in FIG. 3. 1... Paint nozzle, 2... Gun body, 3... Needle valve, 4... Paint spout, 5... Air cap, 6... Center hole, 7... Center air hole, 8... Corner air hole. , 17... sheet.

Claims (1)

[Claims] 1 An annular air outlet is provided on the outside of the paint outlet which is equally spaced from the center of the spray, faces each other, and opens with a forward spray angle, and furthermore, an annular air outlet is provided on the outside of the paint outlet which is equally spaced from the center of the spray and opens with a forward spray angle, and furthermore, an annular air outlet is provided in front of the point where the paint outlet crosses and collides with the paint outlet. A spray nozzle for a spray gun, characterized in that it is provided with at least one pair of angular air outlets that oppose each other so as to collide with each other.