JPS58207965A - Powder coater - Google Patents

Abstract

PURPOSE:To economically and continuously form a coating film having uniform thickness, by providing a paint-withdrawing cylinder having a specified configuration inside a powdery paint-fluidized tank in a manner such that the lower part of said cylinder passes through the tank, and enabling an inlet side to change its vertical position. CONSTITUTION:A paint-withdrawing cylinder 5 has a slender sectional configuration uniformly extending from the vicinity of an inlet 7 to the vicinity of an outlet 12 and passes through a fluidizing tank 1 under the condition that the inlet 7 is existent near the lower part of the surface 8 of a fluidized bed in the fluidizing tank 1. Consequently, in the paint-withdrawing cylinder 5, powdery paint having flowed through the inlet 7 is affected by rectifying action during its spontaneous down-flow through the withdrawing cylinder 5, formed into a laminar stream of certain thickness defined by the sectional configuration of the withdrawing cylinder 5 and let flow out as a curtain stream through the outlet 12. Hereon, the inlet 7 is enabled to change its vertical position in response to the fluctuation in the level of the surface 8 of the fluidized bed, so that the paint flowing out of the withdrawing cylinder 5 is held under the condition of the laminar stream having a predetermined thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a powder coating device for supplying a fixed amount of powder coating to a surface to be coated.

The target surfaces to be coated are mainly wide flat surfaces, curved surfaces without small irregularities, and the outer peripheral surface or inner peripheral surface of large-diameter pipes.

Conventional powder coating methods include fluidized bed dipping and electrostatic spraying. As will be described later, the present invention uses a fluidized bed, but
This fluidized bed and the fluidized bed in the conventional fluidized immersion method have completely different purposes and functions. That is, in the conventional fluidized bed immersion method, a heated object is immersed in a fluidized bed of powder coating for coating, and the fluidized bed itself is the coating site.

In contrast, the fluidized bed in the present invention is a direct supply source of paint and is not the coating site itself.

The powder coating device according to the present invention is rather similar to an electrostatic spray method.

Below, we will discuss the problems encountered with the conventional electrostatic spray method.

(a) - The density of the powder differs considerably between the center and the periphery of the coating pattern, and as shown in Figure 1, the thickness of the coating film (g) tends to be uneven. When recoating horizontally, the thick film part Gll overlaps, increasing non-uniformity.3210 (B) The powder discharge speed is high and a considerable portion of the powder coating hits the surface to be coated. (10 to 80 inches) or scattered. As a result, the following drawbacks occur.

■ Scattered paint particles adhere to areas that have already been painted, causing a defect called "poop".

(Requires a large paint booth due to scattering around the area.)
In addition, the amount of powder in the exhaust gas is large, and the exhaust treatment device is also large-scale.

■ There is a lot of powder paint loss. Powder materials are generally expensive, which increases the cost of coating.

■ If the spray gun becomes clogged, post-treatment is difficult. It takes a lot of effort to manage it so that it doesn't get clogged.

This case includes a first invention (jp!f-defined invention) and a second invention.

The purpose of each invention is to solve the above-mentioned problems.

Measures taken by the present invention for rounding (fold structure) #-i
These are as in the following sections I11 and I[I]. In order to facilitate understanding, they will be described with the numbers used in the drawings (Figs. 2 to 5) relating to the embodiments described later, but this does not limit the technical scope of the present invention. must not be interpreted.

iI] Powder coating fluidized tank (1) and this fluidized tank il
A paint take-out tube (6) is provided for supplying the powder paint received in a flowing state from the powder fluidized bed (1') in the paint surface Q8) to the surface to be coated Q8).

([11 This paint removal tube (6) has a substantially constant cross-sectional shape from the vicinity of the inlet (7) to the vicinity of the outlet α, and is long and narrow, and the inlet (7)
It penetrates the fluidized tank (1) in a state near the bottom of the fluidized bed surface (8).

The effects of the configurations [I] and t[I) above are as follows.

IAI In the paint take-out tube (5), the powder paint that flows in from the inlet (7) is subjected to a rectifying effect while flowing naturally inside the shell of the take-out tube (6), and is regulated by the cross-sectional shape of the take-out tube (5). This becomes a laminar flow with a constant flow and flows out from the outlet (12) in the form of a curtain flow. Since the outflow is a natural flow, the outflow speed is much slower than a forced spray using compressed air.

(8) The above constituent effects produce the following effects.

■ The laminar flow of paint that has reached the surface to be coated (I8) calmly settles down on the surface to be coated (118)
Since the paint is moving relative to the paint, this kind of silent paint transfer occurs continuously.

Therefore, a relatively thick coating film u9> having a uniform thickness is continuously formed on the surface to be coated.

■ Powder scattering on the coated surface 1181 cannot be controlled.

Therefore, there is less occurrence of so-called "spots" and less loss of powder coating. It also has advantages in terms of paint booth volume and exhaust processing capacity.

The paint removal tube (6) rarely gets clogged, and even if it does, it is easy to clean.

Thus, the effects of the present invention are as follows: (a) It improves the precision of the paint film shape; (d) It contributes to the simplification of equipment; and (c) It reduces paint loss and contributes to economicalization.

Next, the measures taken by the second invention are 1. In addition to the gist structure II) and (the river) according to the first invention described above,
The following section consists of one book.

[111] The paint outlet tube (5) is configured such that its inlet (7) is movable up and down (see the embodiment shown in FIG. 6).

The effect of this circle configuration is as follows.

(Q: In the previous paragraph, it was stated that the powder paint becomes a constant laminar flow αη due to the paint removal tube [6). Therefore, the flow rate of the powder paint to be replenished into the fluidized tank (1) may be set equal to the flow rate outflow from the paint take-out tube (6).

However, both the replenishment flow rate and the outflow flow rate change over time.
As a result, the level of the fluidized bed surface (8) fluctuates up and down, causing fluctuations in the high ζ cap between the inlet (7) and the paint outlet tube (6). Although fluctuations in the flow rate of the outflow are not large, problems still arise if they accumulate over time. The larger the gap, the greater the flow rate into the inlet (7). but,
As long as the difference from the set cap is within a certain range, the flow rate outflow from the take-out tube (6) is also approximately constant and does not pose a practical problem.

However, if the difference from the set gap exceeds the allowable range, the outflow flow rate will be too large or too small, which will interfere with the painting process.

It may cause a blockage, or the entrance may become clogged (7)
The state where the fluidized bed surface is below and there is no inflow (empty state 0)
may occur.

The vertical displacement of the inlet (7) of the present structure deals with these two situations. That is, in response to level fluctuations on the fluidized bed surface (8), the inlet (7) is repositioned up and down so that the height gap between the fluidized bed surface (8) and the inlet (7) is within an allowable range. It is.

As a result, if there is a change in the replenishment flow rate, there will be a change in the outflow flow rate or replenishment flow rate, albeit by one violet.
Even if considerable level fluctuations occur on the fluidized bed surface (8) as a result of accumulation, the paint removal tube (6)
The paint flowing out is maintained in a laminar flow state with a constant thickness.

In this way, the effects of the second invention are, in addition to the effects (a), (b), and (c) of the first invention described above, as well as Regardless of fluctuations,
This means that the high precision of coating film formation mentioned in (b) can be maintained.

Next, an embodiment of the present invention will be described based on FIGS. 2 to 5.

At the bottom of the fluidized tank 111, there is an air chamber (3) partitioned off by a perforated floor plate (2), to which an air supply pipe (4) is connected. The paint removal tube (5) vertically penetrates the floor plate (2) and the tank bottom plate (6). To position. In other words, there is a surface (8) just above the entrance (7).
), the replenishment flow rate is adjusted so that (
9) is a supply pipe that supplies powder coating material to the fluidized tank (1) at a constant flow rate. This supply pipe (9) is branched into two,
Each branch pipe t101, 1101 has an output il#(f+1
located symmetrically with respect to Branch pipe (lO) outlet (+
+1 is at the center of the width direction of the take-out cylinder (6),
5) It is open in the direction away from.

This is done in order to prevent unnecessary pulsations from occurring in the central portion of the flow surface (8) where the replenishing paint is about to flow into the outlet (7) due to the inflow pressure of the replenishing paint.

The paint extraction surface (5) is from the inlet (7) to the outlet Q2).
It has a constant cross-sectional shape and is elongated.

Both ends +131 and αj in the width direction are tapered. This is done by setting the flow rate per unit area at both ends +131 and +13 so that the thickness of the overlapping part is equal to that of the other parts when repainting as shown in Figure 4.
This is because each part has about half the IK of the other part.

(A) to (C) in FIG. 5 show the state of use.

α4 is a long flat plate, 0Ii3 is a curved plate, and Til is a pipe. The plate is moved horizontally.

The curved plate 069 is moved so that the falling point of the laminar paint flow αη does not change. The pipe 0φ is moved while being rotated. In other words, it is a spiral feed, and the moving speed is determined so that it advances by the width of the paint laminar flow Q1 in one rotation so that overcoating is appropriate. Q4 is the surface to be coated, and IcJ is the coating film.

Next, an embodiment of the second invention will be described based on FAE diagrams.

The paint removal cylinder (6) consists of a fixed main body cylinder (A) and nine movable cylinder rings which are fitted onto the main body cylinder (A) in close contact and can freely slide up and down. The upper end between the movable parts is the entrance (7);
is moved up and down together with the movable tube l.

The other configurations are the same as the embodiment of the first invention.

As a modification of this example, the paint removal tube (6) is made into a single piece, and the entire fluidized tank flN? : By moving up and down against
An embodiment in which the height position of the inlet (7) is adjusted is also conceivable. In this case, the extraction space (fl) and the perforated floor plate (2)
A sealing structure is provided between the tank bottom plate (6) and the tank bottom plate (6).

FIG. 7 shows a modification of the outlet of the take-out tube (6). The tsuma-sho outlet (the opening is symmetrically narrowed at 1 liter). This configuration may be applied to both the first invention and the second invention.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the electrostatic spray method, FIG. 2 is a sectional view showing an embodiment according to the first invention, FIG. 8 is a plan view showing the state of use, and FIG. 4 is a sectional view showing overcoating. 5(a) to 5(c) are explanatory diagrams of various types of use B, FIG. 6 is a sectional view showing an embodiment according to the second invention, and FIG. 7 is a sectional view of an applied example. (1)...Fluidized tank, (1')...Powder coating fluidized bed, (5)...Paint removal tube, (7)...
...Inlet, (8) ...Fluidized bed surface, (+
2) Exit, Figure 4 Figure 5 (a)
(b) ()9 Figure 6 Figure 7

Claims (1)

[Claims] ■ Fluidization tank (1) of a powder coating meter and this fluidization 411fl
A paint take-out tube (5) that supplies the powder paint received from the powder paint fluidized bed (1') in the fluidized bed (1') to the surface to be coated is provided. (7) The fluidized bed (1 ) through the powder coater. ■ A fluidized powder paint tank (1) and a paint take-out tube (5) that supplies powder paint received from the circular powder paint fluidized bed (1') to the surface to be coated. ), the paint removal tube (5) has a substantially constant cross-sectional shape from the vicinity of the inlet (7) to the vicinity of the outlet a and has a long cape, and the inlet (7) ) on the fluidized bed surface (8
) The powder coating device is located near the bottom and passes through the fluidized tank (1), and the paint outlet tube (6) is configured such that its inlet (7) is movable up and down.