JPH0643177Y2 - Electrodeposition coating device for inner surface of tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an electrodeposition coating apparatus for the inner surface of a cylindrical tank.

[Conventional technology]

A cylindrical tank, as shown in the vertical sectional view of FIG.
To coat the inner surface of a tank whose interior is partitioned into two or three chambers with a partition wall and only a small-diameter base is provided on the side wall, conventional spray coating has been practically used. There is no suitable means.

Here, 2 is a small-diameter screw cap for connecting a pipe, a safety valve, a drain valve, etc., which are respectively provided at the center of the end plate and the cylindrical portion.

[Problems to be solved by the device]

However, spray coating has the following problems.

(1) The spray nozzle cannot be inserted unless the inner diameter of the die is considerably large.

(2) There is no suitable means to inspect whether the coating film has a uniform thickness.

(3) Since it is difficult to spray coat the entire inner surface with a uniform thickness, the thickness of the coating film varies, and several years later, corrosion starts locally from the thin portion of the coating film.

Therefore, in order to solve these problems, the applicant of the present invention inserts a hollow rod-shaped electrode, which doubles as a water washing nozzle, into the tank by using a mouthpiece attached to the tank, and then, while rotating the tank, electrodeposition is performed. We have developed an economical method for coating the inner surface of a cylindrical tank that allows the entire inner circumference to be coated quickly and reliably with a uniform thickness. An electrode mounting structure that allows rotation is required.

The present invention has been proposed in view of the above circumstances, and is for an inner surface of a tank that can supply the electrodeposition coating current into the tank while allowing the rotation of the tank and wash the electrodeposition coating surface with water. An object is to provide an electrodeposition coating device.

[Means for Solving the Problems]

Therefore, in the invention of the first item, a rod-shaped electrode is inserted from the outside through a mouthpiece attached to the center of the end plate on the central axis of a cylindrical tank whose both ends are closed by end plates, and the inside and outside of the tank are electrically charged. In an electrodeposition coating apparatus for tank inner surface, which is immersed in a coating liquid, the above electrode is used as a positive electrode, the above tank is used as a negative electrode, and a DC voltage is applied between the two to apply electrodeposition to the inside surface of the tank. An insulating hollow shaft for engraving a screw to be screwed into the mouthpiece and having the other end coaxially extending over an appropriate length to rotatably support the tank, and a tip extending through the central hole of the hollow shaft into the tank. A metal skin is exposed for an appropriate length, and a portion subsequent to the metal skin, which is to be immersed in the electrodeposition coating solution, has a rod-shaped electrode coated with an insulating film.

Further, in the invention of the second aspect, in the first aspect, the rod-shaped electrode is formed by a hollow shaft, and the tip end peripheral wall of the rod-shaped electrode located in the tank is supplied from the base end portion through the hollow shaft. It is characterized in that a plurality of nozzle holes for exposing the cleaning water to be exposed are formed.

[Action]

With such a configuration, the tank is filled with the electrodeposition coating liquid, and when the electrodeposition coating is performed by applying a predetermined voltage between the electrode and the tank, the tank rotates around its central axis. Since the residual air in the tank moves in the circumferential direction relative to the inner surface of the tank, the inner surface of the tank is in contact with the electrodeposition coating solution all over, and the inner surface of the tank is not affected by the residual air. The coating film is formed with a thickness of 1, and after the electrodeposition coating, washing water is sprayed from the nozzle hole of the electrode to wash the inner surface of the coating, so that uniform, smooth and strong inner coating can be performed.

〔Example〕

An embodiment in which the present invention is applied to a one-chamber type air tank will be described with reference to the drawings. FIG. 1 is a side view showing the tank in an electrodeposition coating bath, and FIG. 2 is a portion showing a supporting portion of the tank shown in FIG. FIG. 5 is a side view, FIG. 3 is a partially enlarged vertical sectional view showing the bearing of FIG. 2, FIG. 4 is a perspective view and a front view showing the pivoting point of the tank of FIG. 1, and FIG. FIG. 6 is a perspective view showing the washing procedure of FIG. 6, and FIG. 6 is a side view showing the electrodeposition coating procedure and the washing procedure in the case of a three-chamber air tank.

First, in FIGS. 1 to 3, the same reference numerals as in FIG. 7 denote the same members as in FIG. 7, and 1 denotes a horizontal cylindrical air tank (hereinafter referred to as a tank). Each of the bases 2 is projectingly provided on the central axis.

Reference numeral 3 denotes an insulating bush screwed into each of the bases 2. The insulating bush 3 is made of a metal bush whose entire circumference is covered with an insulating film. The head is coaxial with a non-conductive hollow shaft made of synthetic resin. 4 is projected.

Reference numeral 6 is a hollow rod-shaped electrode (hereinafter referred to as an electrode) made of a stainless pipe inserted through the hollow shaft 4, the insulating bush 3 and the center hole of the base 2, and the stainless steel is exposed at the portion extending into the tank. A plurality of nozzle holes 7 are bored in the radial direction and the diagonal axis direction, and the portion other than the exposed portion where the electrodeposition coating solution is dipped is covered with an insulating film 8.

Reference numerals 9 and 9 are a pair of nylon bearings in which inner races are fitted to the hollow shafts 4 and 4, respectively, and the outer races of the bearings 9 are a pair of support angles 10 and 10 which are vertically installed on a ceiling beam (not shown).
Affixed to the lower end of the tank, the distance between the support angles 10 and 10 is expandable and contractable to accommodate various lengths of the tank. Reference numeral 11 is a sprocket fitted to one shaft end of the hollow shaft 4, and the sprocket 11 can be rotated in both forward and reverse directions by a motor (not shown) via a chain 12.

In such an apparatus, as shown in FIG. 1, the coating is carried out by first coating the epoxy resin coating with the tank 1 in a state where the hollow shafts 4, 4 projecting at both ends thereof are horizontally supported via bearings 9. , Immersed in a coating bath consisting of solvent and water, with the tank filled with the coating liquid, the electrode 6 is the positive electrode, the tank 1 is the negative electrode, and a DC voltage of 250 to 350 V is applied between the two, and the inner surface of the tank Perform electrodeposition coating of.

At that time, since the caps attached to the tank are all open, the electrodeposition coating is performed while the tank is also filled with the electrodeposition coating liquid, but some air remains in the tank. Therefore, in order to prevent this residual air 14 from interfering with the contact between the tank inner surface and the electrodeposition coating liquid,
Via 12 and sprocket 11, as shown in FIG.
By rotating the tank 1 around the central axis, the inner surface of the tank is uniformly immersed in the coating liquid. Although the rotation of the tank may be in the same direction, in the case of the present embodiment, as shown by the arrow in the figure, it is practically preferable to reciprocally rotate the tank in the forward and reverse directions within an angle range of about 60 °. .

In order to electrodeposit the inner surface of the tank, dip the entire tank in the coating solution bath at the same time as or before or after the inner surface coating, so that the outer surface of the tank is also electrodeposited using the external electrodes. This is because it is convenient.

Here, the parts other than the exposed part of the electrode 6 are covered with an insulating film, and the entire surface of the insulating bush 3 and the hollow shaft 4 is also covered with an insulating layer, so only the exposed part of the electrode is coated. No current flows through the liquid to the inner surface of the tank, and no short-circuit current flows due to direct contact between the electrode 6 and the tank 1. Further, no current flows from the portion of the electrode outside the tank to the outer surface of the tank through the external coating liquid.

Further, depending on the size and structure of the tank, the electrodes are inserted into the caps of one end plate or the end caps of both end plates for electrodeposition coating.

After the electrodeposition of the paint was completed, the tank was pulled up from the coating solution bath, and as shown in FIG. 5, washing water was supplied to the center hole of the electrode 6, and the washing water was bored in the electrode 6. The inner surface of the paint that has been ejected from the plurality of nozzle holes 7 in the radial direction and the oblique axis direction and has adhered to the inner circumference of the tank is uniformly washed with water to make the surface smooth.

When the washing with water is completed in this way, the tank is vertically supported to remove the residual water, and the residual water is removed from the base 2 at the lower end.

In addition, although the above embodiment describes the one-chamber type tank,
Two-chamber type (B), three-chamber type tank (C) as shown in FIG.
Etc., the chambers near both ends are subjected to paint electrodeposition, washing with water and dehydration in substantially the same manner as in the above-mentioned embodiment using the caps, and the intermediate chamber is provided with a side wall as shown in FIG. After inserting the electrode 6'using the base 2'attached to the electrode, electrodeposition coating and water washing can be performed while rotating the tank in substantially the same manner as in the above embodiment.

[Effect of device]

 With such a structure, the following effects can be obtained.

(1) Due to the electric field and current distribution formed between the electrode and the inner surface of the tank, the paint in the coating liquid is electrodeposited on the inner surface of the tank with a uniform thickness quickly and reliably.

(2) During electrodeposition coating, the tank rotates around its central axis, so the inner surface of the tank is uniformly exposed to the coating liquid regardless of the presence of residual air. No uniform electrodeposition coating is performed.

(3) The electrode is supported by the insulating coating on the outer periphery, the insulating bush, and the insulating hollow shaft, and the hollow shaft is supported by the insulating bearing, so a short circuit accident due to poor insulation between the electrode and the tank at the base insertion portion. There is no occurrence of this, and the electrodeposition coating is performed safely.

(4) Since the electrodeposition paint is washed with washing water after electrodeposition, the surface of the paint is finished smoothly and firmly.

(5) Since the electrodes can be made to have a small diameter, the present invention can be applied to the inner surface coating even in a tank having a small diameter die.

In short, according to the first aspect of the invention, the rod-shaped electrode is inserted from the outside through the mouthpiece attached to the center of the end plate on the center axis of the cylindrical tank whose both ends are closed by the end plates, and the inside and outside of the tank are An inner end portion of a tank inner surface electrodeposition coating apparatus for electrodepositing the inner surface of the tank by applying a DC voltage between the electrode by immersing it in an electrodeposition coating liquid and using the electrode as a positive electrode and the tank as a negative electrode. An insulating hollow shaft, which is engraved with a screw that is screwed into the base and has the other end coaxially extending over an appropriate length to rotatably support the tank, and extends through the central hole of the hollow shaft into the tank. By rotating the tank, the tip has an exposed metal skin for an appropriate length, and the portion following this, which is to be immersed in the electrodeposition coating solution, has a rod-shaped electrode coated with an insulating film. While The electrodeposition coating current is supplied into the tank,
INDUSTRIAL APPLICABILITY The present invention is extremely useful in the industry because it provides an electrodeposition coating apparatus for the inner surface of a tank that can be quickly and uniformly coated.

According to the second aspect of the invention, in the first aspect, the rod-shaped electrode is formed by a hollow shaft, and the distal end peripheral wall of the rod-shaped electrode located in the tank extends from the base end to the hollow shaft. Since a plurality of nozzle holes through which the supplied cleaning water is ejected are drilled, a tank inner surface electrodeposition coating device that quickly and smoothly finishes the electrodeposition coating surface can be obtained. It is useful.

[Brief description of drawings]

FIG. 1 is a side view showing a tank in an electrodeposition coating bath of one embodiment in which the present invention is applied to a one-chamber type air tank, and FIG.
FIG. 3 is a partial side view showing a supporting portion of the tank shown in FIG. 3, FIG. 3 is a partially enlarged vertical sectional view showing a bearing shown in FIG. 2, and FIG. 4 is a perspective view and a front view showing a pivoting point of the tank shown in FIG. FIG. 5 is a perspective view showing the procedure for washing the electrodeposition paint on the tank with water, and FIG. 6 is a side view showing the procedure for electrodeposition coating and the washing procedure for a three-chamber air tank. FIG. 7 is a longitudinal sectional view showing various structures of a known cylindrical air tank. 1 ... Air tank (tank), 2, 2 '... Clasp, 3 ...
Insulation bush, 4 ... Hollow shaft, 6,6 '... Hollow rod electrode (electrode), 7 ... Nozzle hole, 8 ... Insulating film, 9 ... Bearing, 10 ... Support angle, 11 ... Sprocket, 12 ……
chain

Claims (2)

[Scope of utility model registration request] 1. A rod-shaped electrode is inserted from the outside through a mouthpiece attached to the center of the end plate on the central axis of a cylindrical tank whose both ends are closed by end plates, and the inside and outside of the tank are immersed in the electrodeposition coating solution. In a tank inner surface electrodeposition coating apparatus for dipping and electrodepositing the inner surface of the tank by applying a DC voltage between the two with the electrode serving as the positive electrode and the tank serving as the negative electrode, the inner end is screwed into the base. An insulative hollow shaft that is screwed and has the other end coaxially extending for an appropriate length to rotatably support the tank, and a tip portion that extends through the center hole of the hollow shaft into the tank for an appropriate length An electrodeposition coating apparatus for an inner surface of a tank, characterized in that a metal skin is exposed and a portion subsequent to the metal skin is immersed in the electrodeposition coating liquid, and a rod-shaped electrode coated with an insulating film. 2. The washing water supplied from the base end through the hollow shaft to the peripheral wall of the tip end of the rod-like electrode located in the tank according to the first aspect. An electro-deposition coating device for an inner surface of a tank, wherein a plurality of nozzle holes to be ejected are formed.