EP4678296A1

EP4678296A1 - Pico de fluido para pistola aerográfica

Info

Publication number: EP4678296A1
Application number: EP25382629.1A
Authority: EP
Inventors: Enrique Sánchez Uriondo
Original assignee: Sagola SA
Current assignee: Sagola SA
Priority date: 2024-07-12
Filing date: 2025-06-20
Publication date: 2026-01-14
Also published as: ES1311982Y; ES1311982U

Abstract

The present invention discloses a fluid tip (1) for a spray gun (2) wherein the tip (1) comprises a central hole (11) to allow a product (8) to come out of the gun and be sprayed with pressurised air (4); the tip (1) being characterised in that the central hole (11) has the shape of a closed line with teeth (13).

Description

Technical field

The present invention can be included in the field of spray guns. More precisely, the invention concerns a fluid tip for a spray gun.

Background

A spray gun is a tool that uses compressed air to atomise paint or other sprayable materials (product) that are contained in a tank. The atomisation process consists of converting the sprayable material (liquid) into very fine particles to be uniformly applied on a surface.
The air and the material to be sprayed enter the gun body independently through ducts and mix on the outside of said body, specifically in the head area of the gun body.
The atomisation of the product is controlled by means of an air nozzle, which is mounted on the gun head, as well as by means of a needle and a fluid tip which are housed in the interior portion of the body. The paint is ejected to the outside through the tip, which has a circular hole in the centre for this purpose.
The nozzle, needle and tip together determine the spray patterns (shape, distribution and texture of the product applied on the painted surface), also called fanning.
The purpose of the air nozzle is to direct the compressed air towards the product to be sprayed in order to atomise the same (break it into small particles and spray them) forming the paint pattern. The spout and needle together control the amount of product coming out into the air stream from the nozzle. The tip serves as a seat for the needle to close or allow the product to pass through. Depending on the distance between the tip and the needle, more or less product will pass through.
The process of painting with a spray gun is based on the physical phenomenon known as the "Venturi effect" where the product contained in a tank is sucked in by a depression created by the air at the nozzle outlet, and by the subsequent atomisation of the product by this same air flow.
The air flow passes through a circular crown formed between the central holes of the tip and the nozzle, which are circular in cross-section. The product flow passes through the central hole of the tip and increases with the air pressure, but up to a certain value, beyond which the product suction drops and faults in the fan pattern occur, such as the so-called "split-fan fault". The air pressure should be 1.5-2.5 bar.

Description of the invention

The present invention presents a fluid tip for spray gun, according to independent claim 1, which overcomes the drawbacks mentioned in the background, due to a particular shape of a central hole of said fluid tip. Optional advantageous features are described in the dependent claims and in the description of an exemplary preferred embodiment. In particular, the present invention also relates to a spray gun including the above-mentioned fluid tip.
With this new tip design, the following advantageous effects are achieved in the painting process:

Make paint atomisation easier.
To achieve uniformity of the paint droplets when spraying.
Finer spraying, even with higher paint supply.
Uniformity of finishings.
Easier tip cleaning.

This new spout design generates a pre-atomisation of the product, due to the increase of the breakage perimeter and the generation of turbulent spots. As a result, the final atomisation of the product is improved and a better uniformity of the spray droplets is achieved together with a finer atomisation even with higher paint supply.
With this tip, there is no loss of suction power; moreover, it allows working with higher pressures compared to another tip with the same characteristics without causing defects in the paint patterns.
The novel tip has a design that achieves greater efficiency when working with the product at the moment of switching from laminar to turbulent flow.
The central hole of the fluid tip of the present invention may or may not have any symmetry. In any case, the particular orientation of the teeth in said centre hole of the fluid tip does not affect the performance of the gun.

Brief description of the figures

The foregoing and other advantages and features will be more fully understood from the following detailed description of exemplary embodiments with reference to the accompanying drawings, which should be considered by way of illustration and not limitation, wherein:

Figure 1 shows a side view of a spray gun according to the present invention.
Figure 2 shows a detailed cross-sectional view of the gun head of figure 1.
Figure 3 shows a perspective view of a fluid tip according to the invention, together with a detail of the central hole of the fluid tip.

Detailed description of an exemplary embodiment

A detailed description of a preferred exemplary embodiment of a fluid tip (1) for spray gun (2), according to the present invention, is provided below with the help of attached Figures 1-3 mentioned above.
The fluid tip (1) of the invention, see figure 3, is found forming part of an air spray gun (2) which is described below together with the tip (1) itself.
According to figures 1 and 2, the gun (2) comprises a body (3), to which pressurised air (4) enters through an air duct (5), and the gun (2) also comprises a head (6), into which the pressurised air (4) from the body (3) is discharged. The gun (2) also includes a tank (7) for the product (8) to be sprayed, which can be paint for example, the tank (7) being connected to the head (6). On an outside part of the head (6), the air (4) is mixed with the product (8).
An air nozzle (9) is housed in the head (6), together with the fluid tip (1) and a needle (10), see figure 2, which cooperate in producing a spraying of the product (8) mixed with the air (4). The tip (1) has an outlet end (15) with a central hole (11) through which the product (8) is ejected to the outside. The outlet end (15) of the tip (1) centrally occupies an air hole (12) of the nozzle (9), so that the air (4) is ejected through a circular crown defined in the air hole (12) outside the outlet end (15) of the tip (1).
The invention is characterised in that the central hole (11) of the spout (1) does not have a circular shape, but has the shape of a closed line with teeth (13), by way of a star, the teeth (13) having sharp or rounded vertexes (14).

List of references

1 Fluid tip
2 Spray gun
3 Body
4 Pressurised air
5 Air duct
6 Head
7 Tank
8 Product to be sprayed
9 Nozzle
10 Needle
11 Centre hole of the product tip
12 Air hole
13 Teeth
14 Vertexes

Claims

A fluid spout (1) for spray gun (2), wherein the tip (1) comprises a central hole (11) to allow a product (8) to come out of the gun and be sprayed with pressurised air (4);
the tip (1) being characterised in that the central hole (11) has the shape of a closed line with teeth (13).
The fluid tip (1) for spray gun (2), according to claim 1, wherein the central hole (11) has the shape of a star.
The fluid tip (1) for spray gun (2) according to any of claims 1-2, wherein the teeth (13) have sharp vertexes (14).
The fluid tip (1) for spray gun (2) according to any of claims 1-3, wherein the teeth (13) have rounded vertexes (14).
A spray gun (2), characterised in that it includes the fluid tip (1) of claims 1-4.