JPS58133854A - Painting device - Google Patents

Abstract

PURPOSE:To avoid the formation of a pin hole due to foams in a painting film, by providing a nozzle for supplying atomizing gas to spraying so as to be fitted to burst of foams, after jetting spray mixed with gas containing many fine foams. CONSTITUTION:A pressurized painting material is supplied to a mixing chamber through a liquid lead path 17, a valve seat 18 and a liquid lead hole 12, and simultaneously, pressurized gas is supplied to the mixing chamber 7 through a gas lead path 20 and a gas lead holle 11. The pressurized painting material and gas which are made to flow into the chamber like a tangent are turned and mixed in the chamber 7, and fine foams are generated, and are jetted conically into the atmosphere from a painting material nozzle. On the other hand, through a gas lead path 21, a gas lead hole 14 and a ventilating path 28, the pressurized gas is jetted as atomizing gas from an annular nozzle 3 so as to collide and contact with the outside circumferential side of said conical spraying, and burst of the fine foams is quickened.

Description

[Detailed Description of the Invention] A spray device that mixes pressurized gas and pressurized liquid and then sprays them from a spout as a large number of microbubbles while maintaining the pressure, releases the foam into the atmosphere and then sprays the foam into the atmosphere. Since it can be ruptured by the pressure of the internal gas, it is expected to be a spray device with good atomization, but when it comes to canning paint, the viscosity of the paint makes it difficult for the foam to rupture. There is a serious defect in that it tends to remain in the film and create pinholes that can be said to be fatal in painting.Therefore, it may be suitable for spraying diluted paint using a large amount of solvent, but it is not suitable for spraying with high viscosity paint. It was inappropriate for Fountain 11.

In order to prevent the formation of pinholes due to foam in the paint film, the present invention effectively ruptures the ejected foam during the propulsion process before it reaches the surface to be painted. The present invention is characterized in that the atomizing gas is actively supplied and brought into contact with the spray, and the embodiment illustrated in the accompanying drawings will be described in detail below.

The embodiments shown in FIGS. 1 and 2 are coating apparatuses adapted to cone-shaped spray, which include a gas-liquid mixing section (1) and a hot paint nozzle (
2) and an atomizing head (4) with an atomizing gas nozzle (3)
is fixed to the front end of the main body (5) with a mounting nut (6), and the gas-liquid mixing part (1) includes a conical part that expands rearward behind a small diameter hot air paint nozzle (2). A mixing chamber (γ) consisting of a short cylindrical portion is provided, and an air guide path (
8) The paint nozzle member is carved so that the (8) and liquid guide channels (9) (9) are opened alternately.
) A relay member (towards ) is formed by sequentially fitting from the rear in a liquid-tight manner into a holder 〇c9 which has an air guide hole )) on the outer periphery front end and has a tapered receiving surface ( 咒) on the front end of the outer periphery, and the main body (5 ) is provided with a liquid guiding path (b) in the front and back direction in its center, and a valve seat (b) is fitted to the front end of the valve seat. A rod is provided to connect the liquid guide path (
17) Make it open and close 11! Alternatively, the main body constructed in this way (
The holder (16) is attached to the front end of the relay member (13).
), the liquid guide hole (b), the air guide hole (11), and the air guide hole) are connected to the valve seat (e), the air guide path, and the air guide hole, respectively.
The nut (2) has a tapered depression surface facing each other with a packing (2) so as to communicate with each other separately.
6) to securely fix the nut (
In 6), a circular hole is bored in the center of the front end wall so that together with the mixed air paint nozzle (2), an annular atomizing gas nozzle (3) is formed. At the same time, the intermediate gap between the front surface of the holder and the front end wall of the nut (6) is used as a ventilation path (C) to guide the atomizing gas from the air guide hole (C) to the nozzle (3). Flow control valves -, ell, and 0υ are provided upstream of the liquid guide path (b), the guide path (ii), and 90 in the main body (5), respectively.

Based on the above configuration, when the control valve is appropriately adjusted, the liquid guide path (b) is formed by retracting the valve rod (b).

After passing through the valve seat (e), liquid guide hole (b), and liquid guide groove (9), the number 1 =
At the same time, when a pressurized paint of about y/c- is supplied to the mixing chamber (7).

With the control valve properly adjusted, the air guide path (a),
Pressurized gas at a pressure equal to or slightly higher than the paint pressure is supplied to the mixing chamber (7) through the annular groove), the air guide hole (11), and the air guide groove (8). The pressurized paint and gas flowing tangentially into the chamber mix while swirling, generate microbubbles that seal the gas, and are injected into the atmosphere from the paint nozzle (2) in a conical shape. Most of the microbubbles burst due to the pressure of the pressurized gas inside them, becoming even finer mist droplets that adhere to the surface to be coated. The conical spray is carried out from the annular nozzle (3) using pressurized gas of about 1 to several laps/L as atomizing gas through 9 ventilation channels (into the air guide path, annular groove) and in the air guide hole. This not only accelerates the destruction of the microbubbles and breaks them into complete microfoam droplets before they reach the surface to be coated, but also reduces the amount of spray needed. This prevents the particles from scattering outward.

The embodiments shown in FIGS. 3 and 4 are examples of obtaining fan-shaped spray, and instead of the annular atomizing gas nozzle (3) in the above embodiment, flattening of the spray is applied from both sides of the spray. Flattening and atomizing gas nozzle facing diagonally inward (3)
(3) is provided in the holder (16) so as to communicate with the air guide hole, and the other structures are the same as those in the above embodiment, so the reference numerals are given in the drawings and the explanation will be omitted.

The embodiment shown in FIG. 5 is an apparatus for forming a fan-shaped spray, and the mixed air paint nozzle (2) is a lip-shaped orifice formed by, for example, the intersection of a dome-shaped concave cavity and a figure-7 groove. A flat blow nozzle with a molded nozzle is adopted, and the gas is made to flow in from the outside through a narrow air guide path (to) intersecting the axis at the throat part as the gas-liquid mixing part (1). We adopted a Venturi tube that allows the paint to flow through the main pipe from the rear and not only mixes gas and liquid under pressure at its throat but also generates foam, and other configurations are described above. Since there is no difference in nature between FIG. 1 and FIG. 2, the same reference numerals 7 are used in the figures and the explanation thereof will be omitted.

In the embodiment shown in Fig. 5, the tip of the holder (16) for the annular atomizing gas (3) is formed into an oval shape that widens into the orifice-shaped nozzle of the nozzle (2) as shown in Fig. 6. It is preferable to supply the atomizing gas intensively to both sides of the fan-shaped sprayed paint using a venturi tube. It is preferable to form a structure in which the throat portion is divided into front and rear parts, and when a protrusion is provided on the dividing surface and joined together, an air guide path perpendicular to the axis is formed.

In the above embodiment, the gas-liquid mixing section (1), the paint nozzle (2)
), the valve seat (the tip of the valve rod (I9) is preferably made of cemented carbide, and air is usually used as the gas to be mixed with the paint and the atomizing gas, but Naturally, steam or other gases may be applied depending on the type or coating conditions.

Furthermore, the atomization effect can be further improved by supplying the paint to the apparatus of the present invention after heating it or by applying an electrostatic coating method.

As explained above, according to the present invention, pressurized gas and pressurized paint are mixed and then atomized, and atomizing air is supplied so as to actively collide with the spray. Therefore, it is possible to effectively crush the foam produced by mixing into even finer mist droplets before it reaches the surface to be painted, and it is therefore possible to use high-viscosity paint, which has been difficult to do in the past. Low-pressure spraying can be easily realized with a simple configuration, and it is also applicable to thick film coating similar to airless spraying, and has advantages such as no tail generation when performing fan-shaped spraying.

[Brief explanation of the drawing]

In the drawings, FIG. 1 is a longitudinal sectional side view showing a coating device of the present invention in one embodiment, and FIG. 2 is a line 1-I in FIG. 1.
3 and 4 are a longitudinal sectional side view and a front view of main parts showing other embodiments, respectively.
6 and 6 are a longitudinal side view and a front view of only the main parts, respectively, showing still another embodiment, FIG. 7 is a longitudinal front view taken along the line ■-■ in FIG. 5, and FIG. 8 is a venturi tube. This is an exploded perspective view. (1)... Gas-liquid mixing section (2)... Mixed air paint nozzle (3)... Gas nozzle for atomization Patent applicant: Hiroki Yanuchi: 3 Figure 7 Figure 4 Figure 6

Claims (1)

[Claims] A coating device in which pressurized gas and pressurized paint are mixed in a gas-liquid mixing section and sprayed from a hot air paint nozzle as a mixed air spray containing a large number of microbubbles, and the microbubbles are mixed in the paint film. A coating apparatus fl is provided with a nozzle that actively supplies atomizing gas to the mixed air spray after injection so as to adapt to the bursting of the foam, in order to prevent the mixture from being mixed with the foam.