JPH025144B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an airless spray nozzle that pressurizes liquid such as liquid paint to high pressure and sprays it at high speed from a small jet port to atomize it by friction with air. The present invention relates to a nozzle in which the liquid to be ejected is well atomized over the entire ejection pattern.

In airless spray painting, in order to efficiently form a uniform coating film, an elongated lip-shaped spout is formed at the tip of the nozzle tip to spray the liquid paint in a thin film, which is atomized by friction with the air and spread into fan-shaped particles. Generally, the ejection port is spread out to reach the object to be coated, but both longitudinal ends of the elongated ejection port are close to the inner wall surfaces on both sides and have a large resistance.
Since the ejection speed is lower than that in the center, atomization is insufficient, and coarse side streams called tails are generated on both sides of the well-atomized main stream in the center, which can damage the surface to be coated. It had some drawbacks. For this reason, a method was proposed in which a small-diameter orifice was provided at the rear of the nozzle tip to equalize the flow velocity of the paint within the nozzle tip, but this increased flow resistance and reduced the ejection pressure, resulting in a drop in paint flow rate, especially when the viscosity was low. With the exception of paints, atomization was actually hindered.

It is an object of the present invention to provide a nozzle that eliminates such drawbacks and is capable of atomizing even highly viscous liquid well over the entire spray pattern.

EMBODIMENT OF THE INVENTION Hereinafter, an embodiment in which the present invention is applied to a coating nozzle will be described based on the accompanying drawings.

In the first embodiment of the present invention shown in FIGS. 1 to 3, the nozzle tip 1 is made of a hard material such as cemented carbide or ceramic, and has a flange 2 formed on the outer periphery of the rear end and a flange 2 at the center of the rear surface. A guide hole 5 consisting of a tapered conical part 3 and a small diameter part 4 connected to the tip is recessed near the tip, and a V-shaped cut groove reaching the small diameter part 4 is formed on the tip surface. Therefore, as shown in FIG. 2, a lip-shaped elongated spout 6 is open. As shown in FIG. 3, the flow regulator 7 has three projecting pieces 9 radially formed at equal angular intervals on the rear end of a rod-shaped main body 8 with a tapered end and a spherical tip surface. , a conical guide protrusion 10 is formed at the center of the rear end surface, and the body 1
Insert the nozzle tip 1 into the stepped hole 12 made transparent in the center of 1.
are fitted and the flange 2 is butted against the stepped surface,
The fluid regulator 7 is attached to the holder 13 by fitting the projecting piece 9 into the enlarged diameter stepped portion 15 formed at the tip of the center hole 14 of the cylindrical holder 13, and the external thread 1 formed on the outer periphery thereof.
6 is screwed into the female thread 17 formed on the body 11, the nozzle tip 1 and the fluid regulator 7 are tightened and fixed between the body 11 and the holder 13, and the main body 8 of the fluid regulator 7 is inserted into the guide hole 5 of the nozzle chip 1. By screwing the hub nut 18, which is located concentrically with the gun body 19 and whose tip is close to the inner wall surface of the conical part 3 and which is hooked on a flange protruding from the outer periphery of the rear end of the body 11, to the gun body 19. The holder 13 is attached to the tip of the gun body 19 with the center hole 14 of the holder 13 aligned with the paint pressure passage 20.

In this embodiment, liquid paint pressurized to high pressure by a paint pump is transferred from the paint pressure passage 20 to the center hole 1 of the holder 13 by opening an on-off valve (not shown).
4, spreads in the radial direction along the guide protrusion 10 at the rear end of the fluid regulator 7, and flows into the guide hole 5 of the nozzle tip 1 through three gaps formed between the protrusions 9. However, in this case, the main body 8 of the fluid regulator 7 is arranged concentrically, and its tip is close to the inner wall surface, so the liquid paint is pressed against the inner wall surface of the conical part 3 and spreads over the entire circumference. Then, it is accelerated on average and flows into the small diameter portion 4. Therefore, the liquid paint forms a thin film into the atmosphere at approximately the same high speed at both ends and the center of the elongated lip-shaped spout 6 in the length direction, and is spread over the entire width due to friction with the air. The particles are well atomized and spread out in a fan shape to reach the object to be coated.

Next, a second embodiment of the present invention will be explained based on FIGS. 4 and 5. In this embodiment, as shown in FIG. integrally protrudes a rod-shaped flow regulator 27,
Except that three through holes 29 connected to the center hole 14 are formed around the center hole 14 at equal angular intervals, the structure is the same as that of the first embodiment, and its function is also the same. This has the advantage of making assembly and disassembly easier.

Note that the present invention can also be applied to spraying liquids other than paint.

As specifically explained in the above embodiments, the airless spray nozzle of the present invention has a nozzle tip with an elongated ejection port formed at the tip and a tapered guide hole reaching the ejection port formed on the rear surface. The gist is that a rod-shaped fluid regulator is disposed approximately concentrically within the guide hole, with at least a tip portion positioned close to the inner wall of the guide hole, and the liquid flowing into the guide hole is aligned. Due to the presence of fluid, it is pressed against the wall surface and accelerated uniformly, so the speed when ejecting from the elongated ejection port is approximately equal at both ends and the center, preventing the generation of tails and ensuring good flow over the entire width. It has the effect of being atomized.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a sectional view, FIG. 2 is an enlarged front view of the nozzle tip, FIG. 3 is a perspective view of the flow regulator, and FIGS. FIG. 5 shows a second embodiment of the present invention, FIG. 4 is a sectional view, and FIG. 5 is a partially cutaway perspective view of a holder equipped with a flow regulator. 1: Nozzle tip, 3: Conical part, 4: Small diameter part,
5: Guidance hole, 6: Spout port, 7, 27: Fluid regulation,
8: Main body, 19: Gun body, 20: Paint pressure passage.

Claims (1)

[Claims] 1. A nozzle chip 1 has an elongated jet nozzle 6 formed at its tip and a tapered guide hole 5 reaching the jet nozzle 6 formed at its rear surface. An airless spray nozzle characterized in that closely spaced rod-shaped flow regulators 7 are arranged substantially concentrically.