JPH09125285A - Electrodeposition coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrodeposition coating device capable of maintaining the fall of the liquid level between an electrodeposition main vessel and an electrodeposition sub-vessel as small as possible even at the time of an ion exchange and eliminating the intrusion of air by bubbling. SOLUTION: This electrodeposition coating device has the electrodeposition main vessel 1 and the electrodeposition sub-vessel 4 communicating with the receiving inlet 3 of the liquid overflowing from the main vessel. The electrodeposition sub-vessel is divided to a chamber A on the side communicating with the receiving inlet and a chamber B on a non-communicating side by a partition plate 6 slightly lower than the liquid level at the time of ordinary operation. The carry-over of the liquid by the ion exchange, etc., is mainly executed from the chamber B to prevent the fluctuation of the liquid surface in the chamber A and to maintain the min. fall between the liquid surface of the electrodeposition main tank and the liquid surface of the receiving inlet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeposition coating apparatus which eliminates foaming of an electrodeposition liquid for electrodeposition coating a metal mold material such as aluminum or iron.

[0002]

2. Description of the Related Art Generally, an electrodeposition coating apparatus is provided with an electrodeposition main tank and an electrodeposition sub tank communicating with a container for receiving the liquid overflowing the main tank, and the liquid in the electrodeposition sub tank is filtered by a filter. It is purified, the liquid temperature is adjusted by a heat exchanger, and it is returned to the main tank through a reflux path. In addition, the liquid in the electrodeposition sub tank is regularly returned to the electrodeposition sub tank by removing the contaminant ions through an ion exchange device.

In the above case, the reflux path from the electrodeposition sub-tank to the main tank and the path between the electrodeposition sub-tank and the ion exchange device are closed circuits by pipes, and air is not mixed in these paths. If bubbles were generated during the overflow from the electrodeposition main tank to the receiving box, air could be mixed in.

Since the inclusion of air in the electrodeposition liquid causes pinholes and craters in the coating film, the drop of the liquid overflowing the electrodeposition main tank should be kept as small as possible (generally However, it was unavoidable that the liquid level in the electrodeposition sub tank was lowered due to the carry-out of the liquid during ion exchange, resulting in a large drop.

Therefore, conventionally, the capacity of the electrodeposition sub tank is set to 1/3 or more of the capacity of the electrodeposition main tank, or the area of the tank upper surface of the electrodeposition sub tank is widened to prevent Care was taken to prevent the liquid level in the electrodeposition sub-tank from fluctuating extremely when taken out.

[0006]

However, increasing the volume of the electrodeposition sub-tank or widening the area of the upper surface of the tank has a limit due to the installation space, so the electrodeposition main tank is practically used. It was difficult to keep the difference between the electrodeposition sub-bath and the electrodeposition sub-bath small. Moreover, as the number of kinds of electrodeposition liquids has increased in recent years, the number of compositions that easily foam is increasing, and a drastic countermeasure is required.

In view of the above points, the present invention makes it possible to keep the liquid level difference between the electrodeposition main tank and the electrodeposition sub tank as small as possible even during ion exchange, and to eliminate the inclusion of air due to bubbling. An object is to provide an electrodeposition coating device.

[0008]

In order to achieve the above object, the present invention comprises an electrodeposition main tank and an electrodeposition sub tank which communicates with a container for receiving the liquid overflowing the main tank. Divide the tank into a chamber A on the side communicating with the receiving chamber and a chamber B on the non-communicating side with a partition plate that is slightly lower than the liquid level during normal operation. First, it is performed from the chamber B so that the liquid level in the chamber A is not changed and the drop between the liquid level in the electrodeposition main tank and the liquid level in the receiving basin can be kept to a minimum.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of an electrodeposition coating apparatus according to the present invention will be described with reference to FIG. In the figure,
Reference numeral 1 denotes an electrodeposition main tank which serves as an immersion treatment tank for electrodeposition coating. The electrodeposition main tank 1 is provided with a receiving container 3 for receiving an overflow liquid of an electrodeposition liquid (ED liquid) 2.

Reference numeral 4 denotes an electrodeposition sub-tank, and a side wall 4a of the electrodeposition sub-tank 4 is provided with a pipe 5 at an outlet 3a provided at the bottom of the receiving box 3.
It is connected through. Therefore, the liquid surface level of the electrodeposition sub tank 4 is the same as the liquid surface level of the receiving container 3.

The electrodeposition sub-tank 4 is divided by a partition plate 6 into a chamber A on the side communicating with the receiving chamber 3 and a chamber B on the non-communicating side. The upper end 6a of the partition plate 6 is slightly lower than the liquid level L ₀ during normal operation.

A plurality of strainers 7a, 7a are provided in the chamber A.
b is arranged to remove impurities contained in the electrodeposition liquid 2 that has flowed in through the pipe 5 (also serves as defoaming). Therefore, the purity of the liquid on the partition plate side is higher in the room A as well. The liquid level in the B chamber is constantly monitored by the liquid level gauge 8.

An outlet 9a provided at the bottom of the partition A side of the chamber A and an outlet 9b provided at the bottom of the chamber B are provided with an ion exchange device 11 via a switching valve (three-way solenoid valve) 10 and a pump 13. Is connected to the inflow side 12. Therefore, by operating the pump 13 and opening either the outlet 9a of the chamber A or the outlet 9b of the chamber B by the operation of the switching valve 10,
The liquid in the chamber or the chamber B can be drawn out and fed into the ion exchange device 11.

The outlet 14a provided at the bottom of the partition A side of the chamber A and the outlet 14b provided at the bottom of the chamber B have a filter 16 and a heat exchanger 17 via a pump 15.
It is connected to a return path 18 to the main tank 1. That is, by operating the pump 15, the liquid drawn from the chambers A and B is purified by the filter 16, the liquid temperature is adjusted by the heat exchanger 17, and the liquid is returned to the main tank 1 through the reflux path 18. There is. This operation is normally continued.

In order to make the liquid returned to the main tank 1 compatible with the liquid in the main tank, the tip of the reflux path 18 is communicated with a fountain pipe 19 submerged in the bottom of the main tank. In addition, the outlet 14 of room B
An opening / closing valve (solenoid valve) 20 is provided in b.
Is operated by a liquid level gauge 8 that monitors the height of the liquid level in the B chamber, so that the taking out of the liquid from the chamber can be regulated.

A branch path 18a is provided in the return path 18. An on-off valve (solenoid valve) is provided on the branch path 18a.
Nords 22 and 22 are provided via 21. The nozzles 22 and 22 are for passing self-liquid water to eliminate bubbles when the bubbles are generated in the electrodeposition sub tank 4.

The ions sent to the ion exchange device 11 are subjected to removal of miscellaneous ions by the ion exchange device. The ion-exchanged liquid is supplied from the outflow side 25 of the ion exchange device 11 via a switching valve (electromagnetic valve) 26 to an inlet 27a provided at the bottom of the preceding stage of the chamber A or an inlet 27b provided at the bottom of the chamber B.
Is returned to.

The switching valves 10 and 26 and the open / close valves 20 and 2
1 is controlled based on the detected value of the liquid level of the liquid level gauge 8.

Next, the operation will be described. First, during normal operation, the pump 15 is operated and the on-off valve 20 is opened. As a result, the outlet 1 of the chamber A of the electrodeposition sub tank 4
The electrodeposition liquid 2 is drawn out not only from 4a but also from the outlet 14b of the chamber B, is purified by the filter 16 and is adjusted in temperature by the heat exchanger 17 and returned to the main tank 1. In this case, water is sprayed downward from the fountain pipe 19 submerged in the bottom of the main tank 1 and becomes well compatible with the liquid in the main tank.

When the liquid is returned to the main tank 1 through the reflux path 18, almost the same amount of the liquid overflows the main tank 1 and is received by the receiving container 3, and is sequentially passed through the pipe 5 to the electrodeposition sub tank 4 Supplied to room A. The strainer 7a, 7b removes impurities and defoams the liquid that has entered the chamber A, and the liquid is drawn again by the pump 15 and repeatedly circulated.

The liquid level during the circulation is above the upper end 6a of the partition plate 6, that is, at the position of L ₀ , and minimizes the drop at the time of overflow between the electrodeposition main tank 1 and the receiving box 3 and I try not to create bubbles.

Next, during the ion exchange process, in addition to the above-mentioned normal operation, the pump 13 is operated and the switching valve 10 is operated.
To open the outlet 9b of the chamber B of the electrodeposition sub tank 4 (A
The outlet 9a of the chamber remains closed). As a result, the liquid in the B chamber is drawn out by the pump 13 and flows into the ion exchange device 11 through the inflow port 12. At this time, the pure water filled in the ion exchange device 11 is pushed out and the pipe 28
Through the pure water purification device 24. The electrodeposition liquid that has been subjected to the ion exchange treatment in the ion exchange device 11 has the outflow side 25.
When the switching valve (electromagnetic valve) 26 is operated, it is returned to the chamber A through the injection pipe 27a.

In other words, at the time of ion exchange, the liquid drawn out from the chamber B is returned to the chamber A after the ion exchange treatment, so that the liquid level in the chamber B is lowered. When the liquid level gauge 8 detects that the liquid level in the B chamber has dropped to the level of L ₁ , the liquid level gauge 8 closes the open / close valve 20. This stops the withdrawal of the electrodeposition liquid 2 from the B chamber, withdraws only from the A chamber, and returns it to the electrodeposition main tank 1 through the filter 16 and the heat exchanger 17.

When the liquid level gauge 8 detects that the liquid level in the chamber B has dropped to the level of L ₂ , the liquid level gauge 8 operates the switching valve 10 to close the outflow port 9b of the chamber B. on the other hand,
The outlet 9a of the chamber A is opened, and the liquid drawn only from the chamber A is sent to the ion exchange device 11.

At this point, the liquid level in the chamber A drops from the upper end 6a of the partition plate 6 to a slightly lower position H, but the volume of the chamber B is determined in advance so that this position H can be maintained as the level for ion exchange. That is, it is important to consider that the capacity of the room B is slightly larger than the amount taken out to the ion exchange device. That is, it is possible to keep the liquid level of the receiving box 3 that receives the liquid overflowing from the main tank 1 at the above H level even during ion exchange, with the main tank 1 and the receiving box 3 (electrodeposition sub tank 4).
It is important to reduce the head drop and to prevent the generation of bubbles.

Next, after the ion exchange process, the pump 13 is stopped, and then the pure water purified in the pure water purification device 24 is fed into the ion exchange device 11 through the pipe 29 by the operation of the pump 23. As a result, the ion exchange device 11
The electrodeposition liquid remaining inside is pushed out and returned to the B chamber through the inlet 27b by the operation of the switching valve 26, and the liquid level in the B chamber rises to the liquid level L ₀ in the normal operation, It becomes normal operation. Then, the ion exchange operation is repeated again due to the contamination of the electrodeposition liquid.

A safety device works so that the pump 13 is stopped when the liquid level in the chamber B of the electrodeposition sub tank 4 becomes L ₃ or less for some reason. Further, the loss of the electrodeposition liquid 2 due to the coating is supplied to the electrodeposition sub tank 4 through the electrodeposition liquid supply mechanism 30.

[0028]

As described above, the present invention comprises the electrodeposition main tank and the electrodeposition sub tank which communicates with the receiving container for the liquid overflowing the main tank, and the electrodeposition sub tank communicates with the receiving container. The chamber A on the operating side and the chamber B on the non-communicating side are divided by a partition plate that is slightly lower than the liquid surface level during normal operation. By carrying out from the chamber, it is possible to prevent the liquid level in the chamber A from fluctuating greatly, and it is possible to always keep the head of the liquid overflowing from the main tank to a minimum, and to ensure the occurrence of bubbles. It can be prevented.

Further, as a result of the above, it is possible to make the electrodeposition sub-tank significantly smaller than the capacity of the electrodeposition main tank, which has been conventionally required, so that the space can be saved and the amount of the electrodeposition liquid used can be reduced. It is possible to obtain various excellent effects such that the initial cost and the running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of an electrodeposition coating apparatus according to the present invention.

[Explanation of symbols]

 1 Electro-deposition main tank 2 Electro-deposition liquid 3 Receptacle 4 Electro-deposition sub-tank 5 Piping 6 Partition plate 6a Partition plate upper end 7a, 7b Strainer 8 Liquid level meter 9a, 9b Outlet 10 Switching valve 11 Ion exchange device 12 Inflow side 13 Pumps 14a, 14b Outlet 15 Pump 16 Filter 17 Heat exchanger 18 Reflux path 19 Fountain pipe 20 Open / close valve 21 Branch path 22 Nozzle 23 Pump 24 Pure purification device 25 Outflow side 26 Switching valve 27a, 27b Injection inlet

Claims (1)

[Claims] 1. A chamber A provided with an electrodeposition main tank and an electrodeposition sub tank communicating with a receiving container for liquid that overflows the main tank, and a chamber A on the side communicating with the receiving container. And B on the non-communication side
An electrodeposition coating device characterized by being divided into a chamber and a partition plate that is slightly lower than the liquid level during normal operation.