JPS5810471B2 - Method and apparatus for recovering and reusing cleaning liquid and heat in metal surface treatment process - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for recovering and reusing the heat and heat of the cleaning liquid when the first cleaning liquid is water and the second cleaning liquid is hot water in a metal surface treatment process. It is.

In the conventional metal surface treatment process, as shown in FIG. 1, a certain amount of water is replenished to maintain the quality of water during washing and hot water washing, and overflow is discharged from these various types.

In order to maintain the temperature of the hot water washing tank 1, live steam is directly supplied from the boiler to the hot water washing tank 1, and the hot water is discharged as is without heat recovery.

This is problematic from the viewpoint of effective use of water resources and energy conservation.

Therefore, in view of the above-mentioned problems of the prior art, the present applicant has developed a method and an apparatus for performing liquid recovery and reuse in conjunction with heat recovery and reuse in order to solve the problems.

In this development, as shown in Figure 2, a heat exchanger is installed between the cushion tank and the washing tank, which are subordinate to the hot water washing tank, to lower the temperature of the high-temperature water, and the resulting low-temperature water is transferred to the washing tank. However, because the low-temperature water is impure, the water quality in the washing tank becomes poor, and since the metal products are transferred from the washing tank to the hot water washing tank, the water quality in the washing tank also becomes poor. The difficulty is that it's hot.

Therefore, the present invention has been made to solve these difficulties, and aims to stabilize the water quality of the hot water washing tank and the cold water washing tank, and to improve the precision of the product.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be sequentially described below according to an illustrative embodiment.

In Fig. 3, 1 is a hot water washing tank, into which a pipe 2 for introducing live steam faces, a high temperature water recovery pipe 3 is connected to one side, and a high temperature water recovery pipe 3 is connected to the other side. A water discharge pipe 4 is connected.

The other end of the high temperature water discharge pipe 4 communicates with the interior of the cushion tank 5.

The cushion tank 5 is connected to a low temperature water discharge pipe 10 connecting the cushion tank 11 from one side of the washing tank 8 by a pipe 7 passing through a heat exchanger 6.

A pump 9 is interposed between the tank 5 of the pipe 7 and the heat exchanger 6.

A filter 21 is preferably provided between the pump 9 and the heat exchanger 6 to avoid scaling of the heat exchanger 6.
Set up.

A water suction pipe 12 faces inside the cushion tank 11 and communicates with a filter 14 via a pump 13.
communicates with a filtrate storage tank 16 via a discharge pipe 15.

The water storage tank 16 communicates with an ion exchange device 19 via a pipe 18 having a pump 17 provided therebetween.

The ion exchange device 19 communicates with a pipe 20 passing through the heat exchanger 6, and the pipe 20 communicates with the high temperature water recovery pipe 3.
A branch pipe 22 is connected to the part of the pipe 20 that connects the ion exchange device 19 and the heat exchanger 6, and the tip thereof faces the washing tank 8, thus providing a circulation type system. A liquid and heat recovery and reuse device A is configured.

Next, a method for reusing cleaning liquid and heat once by using the recovery and reuse apparatus A configured as described above will be explained.

In the process of repeatedly washing the surface of the metal to be cleaned in the urine washing tank 8 and then washing it in the hot water washing tank 1, the apparatus A first circulates the liquid.

At this time, impure high-temperature water (approximately 8
0℃) is pipe 4. Heat is exchanged with low-temperature pure water in heat exchanger 6 through cushion tank 5° pipe 7, and low-temperature water (approximately 40°
°C) and is sent to the low-temperature water discharge pipe 10, where it joins with the low-temperature water containing impurities from the washing tank 8 flowing there, and is discharged into the cushion tank 11.

This low-temperature water is sent from the water suction pipe 12 to the filter 14 by the pump 13, and is discharged into the water storage tank 16 through the pipe 15 as a filtrate.

From the water storage tank 16, the filtrate passes through a pipe 18 to the pump 1.
7 to the ion exchanger 19.

The filtrate sent to this ion exchange device 19 is adjusted to a temperature suitable for ion exchange.

In the ion exchange device 19, cations (C
a++, Na+, etc.) and anions (so4-, etc.) are removed by ion exchange, and the filtrate becomes pure water.

The low-temperature water (approximately 35°C) that has undergone ion exchange and has become pure water is sent to the heat exchanger through the pipe 20, where it exchanges heat with the high-temperature water (approximately 80°C) containing the impurities mentioned above and becomes high-temperature. pure water (approximately 75C) is collected in the hot water washing tank 1,
Then, the temperature is further increased by blowing in live steam or by other heating means.

On the other hand, low-temperature water (approximately 35℃) that has undergone ion exchange and has become pure water
) is collected into the washing tank 8 via the branch pipe 22.

Thereafter, such operations are repeated to circulate the liquid.

As described above, in the present invention, firstly, the high-temperature water discharged from the hot water washing tank that stores the second cleaning solution in the metal surface treatment process is heat-exchanged with low-temperature pure water and converted into low-temperature water. The low-temperature water containing impurities from the washing tank storing the second washing solution is combined with the water and introduced into the cushion tank, the liquid in the cushion tank is filtered, the filtrate is ion-exchanged, and the purified water from the ion-exchange is produced. The pure water is heated by heat exchange with the high-temperature water and collected in the hot water washing tank, and a portion of the pure water is also collected at a low temperature into the water washing tank, thereby reducing the temperature and heat of the cleaning liquid in the metal surface treatment process. Since the collection and reuse method has been constructed, a certain amount of liquid can be circulated and used as a cleaning liquid even during visits without having to be replenished as in the past, so efficient cleaning can be carried out while helping to save water. Heat exchange is performed by mutually using the low temperature water in the washing tank and the high temperature water in the hot water washing tank, which simplifies the equipment and reduces the energy required for live steam introduced into the hot water washing tank and other heating means. In addition, since the liquid collected in the hot water washing tank and the cold washing tank is a pure liquid, the water quality in both tanks can be stabilized at the same time and the product can be prevented from becoming defective.

Further, in the present invention, secondly, each of the water washing tank for storing the first cleaning liquid and the hot water washing tank for storing the second cleaning liquid in the metal surface treatment step is communicated with each cushion tank, and the hot water washing tank is connected to the cushion tank. A cushion tank subordinate to the washing tank is connected to the cushion tank subordinate to the washing tank by interposing a heat exchanger, and a cushion tank subordinate to the washing tank is connected to a filter, an ion exchange device, and the heat exchanger. A cushion tank subordinate to the water washing tank is connected to the water washing tank by removing the heat exchanger and interposing the filter and the ion exchanger to connect the metal surface to the washing tank. Since we have constructed a system for recovering and reusing the cleaning liquid during the treatment process and the heat, it is possible to collect pure liquid in both the hot water washing tank and the cold washing tank, and the water quality in each tank is maintained at a good quality throughout the operation. As a result, the quality and accuracy of the product can be improved.

[Brief explanation of the drawing]

1 and 2 are schematic explanatory diagrams of a cleaning device in a conventional metal surface treatment process, and FIG. 3 is a schematic explanatory diagram of a cleaning liquid and heat recovery and reuse device in a metal surface treatment process according to the present invention. . 1... Hot water washing tank, 2, 3, 4... Pipe, 5゜11... Cushion tank, 6...
...Heat exchanger, 7...Pipe, 8...
Washing tank, 14... Refilling machine, 16... Water tank, 19... Ion exchange device, 10°12.
15, 18.20...pipe, 22...
- Branch pipe.

Claims (1)

[Scope of Claims] 1. High temperature water discharged from a hot water washing tank that stores the second cleaning solution in the metal surface treatment process is heat exchanged with low temperature pure water and used as low temperature water to store the first cleaning solution. The liquid in the cushion tank is introduced together with low temperature water containing impurities from the washing tank, the liquid in the cushion tank is filtered, the filtrate is ion exchanged, and the purified water resulting from the ion exchange is heated by heat exchange with the high temperature water. In the metal surface treatment process, the cleaning liquid is cooled and collected in the hot water washing tank, and a part of the pure water is collected in the cold water washing tank without being heated. Collection and reuse method. 2. The water washing tank that stores the first cleaning liquid in the metal surface treatment process and the hot water washing tank that stores the second cleaning liquid are connected to each cushion tank, and the cushion tank subordinate to the hot water washing tank is connected to a heat exchanger. communicates with a cushion tank subordinate to the water washing tank through the water washing tank, and communicates the cushion tank subordinate to the water washing tank with the hot water washing tank via a filter, an ion exchange device, and the heat exchanger, and A cushion tank subordinate to the washing tank is connected to the washing tank by interposing the filter and the ion exchange device. Equipment used.