JPH02122098A - Plating liquid circulating type continuous electroplating equipment - Google Patents

Abstract

PURPOSE:To prevent return liquid from being oxidized by entrainment of air therein by connecting an upper tank of plating liquid to a lower tank with a return pipe capable of circulating the plating liquid and holding the plating liquid level in the return pipe constant with both a liquid level detector and a flow rate regulating valve. CONSTITUTION:An upper tank 3 receiving the plating liquid overflowed from a plating tank is connected to a lower tank 8 supplying the plating liquid to the plating tank with a return pipe 11 capable of circulating the plating liquid. An overlow pipe 12 is provided to the upper part of the return pipe 11 and also a liquid level detector 13 of the plating liquid in the pipe is provided to the return pipe 11. The plating liquid level in the return pipe 11 is detected and the plating liquid level in the return pipe 11 is always set near to the bottom part of the upper tank 3 by actuation of a flow rate regulating valve 14. Thereby the plating liquid in the return pipe 11 is prevented from being oxidized by entrainment of air therein and deterioration of performance of the plating liquid is prevented. Further even when the flow rate regulating valve 14 is broken down, the working rate of the plating equipment is prevented from being lowered without stopping plating operation because the overflow pipe 12 exists.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to the deterioration of a plating solution during the return trip when a surface treatment solution, especially an electroplating solution, etc. is circulated between a plating tank and a storage tank. The present invention relates to a continuous electroplating device that prevents the above.

<Prior art> A typical example of circulating a plating solution is disclosed in Japanese Patent Application Laid-open No. 57-198.
As shown in Japanese Patent No. 298, it is as shown in FIG. The plating solution 16 overflowing from the plating tank 2 is once stored in the upper tank 3, then falls down the return pipe 11 and collected in the lower plating solution storage tank 8. At this time, air entrainment was unavoidable.

By the way, electroplating of Fe-based metals has become more common in recent years, but when the PE ions in the plating solution are oxidized, extra chemicals are required to replenish the ions.
Further, there were problems such as an increase in oxidized ions having a negative effect on the appearance of the plating.

To prevent this, it is necessary to minimize air entrainment into the plating solution. In particular, as mentioned above, in the return pipe of the plating solution Vfi ring device, the plating solution that has passed through the cell returns to the circulation tank due to gravity, but especially in the vertical portion of the return pipe, the plating solution draws in a large amount of air. Because of this flow, Fe ions in the liquid are significantly oxidized.

Conventionally, a mechanical liquid level maintenance mechanism using a flow eye 7 and a valve 18 as shown in FIG. It's not realistic because you have to do it.

Furthermore, Japanese Patent Laid-Open No. 63-35799 proposes maintaining the liquid level in the drain pipe, but does not disclose any specific means.

<Problems to be Solved by the Invention> An object of the present invention is to propose a device for preventing oxidation of the plating solution due to air entrainment in the plating solution flowing through the return pipe in a plating solution circulation type continuous electroplating device.

Another purpose is to protect the plating solution W even if the plating solution oxidation prevention device fails or the plating solution level control becomes abnormal.
The i-ring system proposes a device that can be maintained.

<! 1! Means for Solving the Problem> The present invention provides a system in which an upper tank that receives a plating solution overflowing from a plating tank and a lower tank that stores the plating solution to be supplied to the plating tank can be connected to each other so that the plating solution can Continuous electroplating system connected by the plating solution return pipe: First, an overflow pipe whose lower end connects to the lower tank is branched to the upper part of the return pipe, and a flow rate is adjusted to the return pipe near the lower tank. A valve is provided, and a liquid level detector is provided between the branch part of the overflow pipe and the flow rate adjustment valve, so that the plating liquid level in the return pipe can always be maintained at a certain level or higher. This is a continuous electroplating device that circulates plating solution.

<Function> FIG. 2 is an enlarged view of section A in FIG. 1, showing an embodiment of the apparatus of the present invention shown in FIG.

The plating solution from the upper tank 3 passes through the return pipe 11 and is returned to the lower tank 8. In the middle of this return pipe 11, there is a liquid level detector 13 and a flow fft! A PI regulating valve 14 is provided,
When the liquid level detector 13 detects the liquid level, L, the flow ■
The regulating valve 14 is closed and the liquid level is +1. When L is detected, the flow rate adjustment valve 14 is opened. In this way, the liquid level is always maintained between Il, L, and Tori, L. Therefore, by setting the positions of HoL and HoL substantially close to the bottom of the upper tank 3, air entrainment can be avoided.

In addition, in the device of the present invention, the overflow pipe 12 is branched near the upper tank 3 at the upper part of the return gll, so even if the flow ffi adjustment valve f'14 fails or the level control becomes abnormal, Accidents such as overflow of plating solution from the plating cell can be prevented, and plating can be continued.

It goes without saying that the liquid level, L, maintained in the return pipe 11 should be as high as possible, and the flow rate regulating valve 14 should be kept as high as possible.
It is preferable that the position is as low as possible and immediately adjacent to the lower tank 8.

FIG. 3 shows another embodiment of the device of the present invention. Upper tank 3
A sub-tank 15 is provided directly below the sub-tank 15, and a return pipe 11 is connected to this. In this case, since the overflow pipe is provided in the sub-tank 15 and the liquid level detector is also provided to be able to detect the liquid level in the sub-tank 15, the liquid level rises and falls gradually, and the possibility of air entrainment is further reduced.

<Effects of the Invention> Since the plating solution circulation type continuous electroplating apparatus of the present invention is constructed as described above, the return pipe and inside are always filled with plating solution, and oxidation of the plating solution due to air entrainment is prevented. Therefore, not only the amount of plating solution chemicals input can be reduced, but also the quality of plating can be improved. Further, even if the level control fails, there is no need to suddenly stop one operation.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an example of the device according to the present invention, FIG. 2 is a partially enlarged view thereof, FIG. 3 is another embodiment, and FIG. 4 is an explanatory diagram of the prior art.
FIG. 5 is a partial explanatory diagram of a conventional improved example. l...I! l band, 2... plating solution tank,
3... Upper tank, 4... tit pole, 5...
・Electrification roll, 6... Back unroll, 7.
...Dum roll, 8...Lower tank, 9...
Plating solution circulation pump, IO...liquid pipe, 11...
・Return pipe, 12... Overflow pipe, 13
...Liquid level detector, 14...? R! I Ufl valve control, 15...Return liquid receiving sub-tank, 16...Plating solution, 17...Float, 18...Valve.

Claims (1)

[Claims] A continuous electroplating device in which an upper tank that receives plating solution overflowing from a plating tank and a lower tank that stores the plating solution supplied to the plating tank are connected by a plating solution return pipe so that the plating solution can be circulated. , an overflow pipe whose lower end connects to the lower tank is branched at the upper part of the return pipe, and a flow rate adjustment valve is provided in the return pipe near the lower tank, and the branch part of the overflow pipe and the flow rate adjustment valve are provided in the return pipe near the lower tank. 1. A continuous electroplating device with plating solution circulation, characterized in that a liquid level detector is provided between the return pipe and the plating solution so that the plating solution level in the return pipe can always be maintained at a certain level or higher.