JPH0414196B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an immersion type surface treatment method used for degreasing, pickling, phosphate treatment, etc. of metal surfaces, particularly a water-saving type immersion type surface treatment method. Regarding.

[Conventional technology]

As a pre-treatment method for degreasing, pickling, phosphoric acid treatment, etc. of metal products, a method is adopted in which multiple immersion tanks are installed in parallel and the objects to be treated are sequentially transferred from the chemical bath to the next washing tank and immersed. has been done.

In this immersion type surface treatment method, in order to prevent the cleaning effect from decreasing due to an increase in the amount of chemicals brought into each washing tank, fresh water is supplied to the final tank of each washing tank, and then water is added to the previous washing tank in sequence. A method was adopted in which the water was fed forward in an overflow manner and the water was drained from the first washing tank following the chemical tank.

[Problem that the invention seeks to solve]

However, with this method, a large amount of overflow water containing chemical solutions is constantly generated during operation, which not only increases the amount of water used, but also causes pollution problems due to the wastewater and places a heavy burden on wastewater treatment, which increases equipment costs. There was a problem that running costs were high.

The present invention was devised through repeated research in order to solve the above-mentioned conventional problems, and aims to provide a method for efficiently performing immersion surface treatment without drainage or at least with a significant reduction in the amount of drainage. It is.

[Means for solving problems]

In order to achieve the above object, the present invention does not simply drain overflow water from the cleaning zone as in the past, but instead sends multiple stages of cleaning water to the previous zone of each zone in order, and replaces the adhered water with fresh water in the final zone. At the same time, an evaporation chamber is attached in advance to the chemical solution zone or the next-stage cleaning zone, and during operation, hot air is introduced into this evaporation chamber while spraying the chemical solution or cleaning water, and the chemical solution or cleaning water is evaporated with this hot air. , the method is to discharge the hot air together with the hot air.

The present invention will be explained below based on the accompanying drawings.

FIG. 1 shows an overview of the immersion type water-saving surface treatment method according to the present invention, which includes at least one chemical solution zone 1 and a plurality of cleaning zones following this (in the illustrated example, the first cleaning zone to the seventh cleaning zone )2
It has A to 2G. 3 is a pre-treatment drying furnace, 4 is a painting section, and 5 is a paint baking furnace. A conveyor H is installed from the chemical zone 1 to the paint baking furnace 5, and the objects I to be treated such as metal products are transferred by this conveyor H. , chemical solution zone 1 to cleaning zones 2A to 2
They stop in sequence at G, and are immersed in the tank by being raised and lowered.

Figures 2 to 4 show details of the present invention, and the chemical liquid zone 1 includes a tank 6 in which the object to be treated I is immersed and a chemical liquid (acid liquid, chemical conversion liquid, degreasing liquid, etc.) in the tank. It includes means 7 for heating and means for supplying the chemical solution to the tank 6.

1st cleaning zone 2A to 7th cleaning zone 2G
Each of these has immersion tanks 8a to 8g that contain a cleaning liquid and immerse the object to be treated I, and in the illustrated one, the immersion tank 8a of the first cleaning zone 2A and the immersion tank 8g of the seventh cleaning zone 2G are A heating means 9 is provided to perform hot water washing.

Each of the tanks 8a to 8g is provided with water guide pipes 10a to 10g that sequentially extend above the preceding immersion tank.
Pumps P ₁ to _{P 7} are interposed and connected to 0a to 10g, and spray nozzles 11a to 11g are provided via appropriate flexible hoses at the tips of the water guide pipes corresponding to the upper positions of the tanks, respectively. A control valve 12 is installed in the water guide pipes 10a to 10g.
a to 12g are provided and are electrically connected to a detector 13 such as a limit switch as typically shown in the second cleaning zone in FIG. It is designed to open and close automatically based on signals. Note that, if necessary, a ball tap valve 14 facing the preceding immersion tank may be connected to the water guide pipes 10a to 10g.

In the seventh cleaning zone 2G, which is the final cleaning zone, a storage tank 8h is separately arranged, and fresh water is stored in this tank via, for example, a pure water device 15, and fresh water is also stored in this via a pump _P8 . A new water conduit 10h is extended to the immersion tank 8g of the seventh cleaning zone, and a spray nozzle 11h at the tip replaces attached water.

Furthermore, the present invention provides an evaporation chamber 16 of a required volume at a desired location in each zone, preferably in the chemical liquid zone 1 or the first cleaning zone 2A following it, and
A spray nozzle mechanism 17 is disposed within the evaporation chamber 16, and the spray nozzle mechanism 17 is connected to the immersion tank of the cleaning zone by piping, and a hot air blowing section 19 is further provided in the evaporation chamber 16.

The evaporation chamber 16 has a cylindrical or box-like configuration. The installation location may be on the side of the chemical solution zone or the first cleaning zone as shown in Figure 1, or the second
It may be provided in the area immediately above the zone as shown in the figure or in the upper area as in FIG. Depending on the case, they may be connected in separate configurations, but from the viewpoint of efficiency and the like, the method of the above embodiment is preferable.

Although the piping from the tank to the spray nozzle mechanism 17 is optional, it is generally connected to the zone (first cleaning zone in the case of FIG. 2) 2 equipped with an evaporation chamber.
It is preferable to provide a branch pipe 18 in the water guide pipe 10a of A and connect this to the spray nozzle mechanism 17.

The hot air blowing section 19 is connected to a supply source through piping, and specifically connected to an exhaust section of a drying oven, baking oven, deodorizing device, or chemical solution heating means, and utilizes the waste heat thereof. be.

The evaporation chamber 16 is provided with an exhaust pipe 20, a gas-liquid separator 21 and a load fan 22 are connected to the exhaust pipe 20, and the gas-liquid separator 21 is a return pipe for returning the liquid to the immersion tank. 23 are provided.

If necessary, as illustrated in FIG. 2, a part of the water conduit 10a may be guided above its own immersion tank 8a and connected to the spray nozzle 24, so that immersion and spraying can be selectively performed. You may also do so.

Further, as shown in FIG. 4, a heat exchanger 25 such as a hot water boiler or a steam boiler may be disposed in the evaporation chamber 16, and when this is used in combination with hot air blowing, the atmospheric temperature increases. As the amount of moisture saturated in the air increases, the rate of evaporation becomes even faster.

What has been described above is one embodiment of the present invention, and the number of cleaning zones is not limited. Further, the present invention also includes a case where there is another chemical liquid zone next to the final cleaning zone and a plurality of cleaning zones following the final cleaning zone. Evaporation chamber 16
Of course, it is also possible to provide a chemical liquid in the chemical liquid zone 1 to evaporate the chemical liquid.

In other drawings, 26 is a shower booth.

The surface treatment method according to the present invention will be explained based on the above-mentioned implementation apparatus. The object to be treated I is transported by a conveyor H at a predetermined interval and speed to the chemical solution zone 1 and the following cleaning zones 2A to 2G, and is sequentially immersed in the immersion tanks 6, 8a to 8g of each zone.

In this process, in the present invention, fresh water is stored in a storage tank 8h in advance, and the new water conduit 1 is pumped by pump _P8.
0h to the spray nozzle 11h above the immersion tank in the final zone 2g. Further, cleaning water is guided from the immersion tank 8g in the final zone 2g to the spray nozzle 11g above the immersion tank in the sixth cleaning zone 2f, which is the first stage, by a pump _P7 . Thereafter, the cleaning water is sequentially forwarded to the spray nozzles above the tank in the front zone in the same manner, and the cleaning water is also guided from the pump _P1 of the first cleaning zone 2A to the spray nozzle 7 above the immersion tank 6 in the chemical zone 1A.

The object to be treated I is immersed in the immersion tank 6 of the chemical zone 1, and then when it is pulled up, a detection means such as a limit switch is activated, and the control pulp 12a is opened in response to the signal, and the object is guided from the first washing zone 2A in the subsequent stage. The cleaning liquid is showered onto the workpiece by the spray nozzle 11a, and then conveyance begins, reaching the first cleaning zone 2A, and entering the immersion tank 8a.
The main cleaning is performed by immersing it in the water. and,
When the material is lifted out of the immersion tank, the control valve 12b operates the spray nozzle 11b as described above, and the material is washed with the next stage of washing water.
Thereafter, this process is repeated up to the final cleaning zone, and in the final cleaning zone 2G, the spray nozzle 11g performs spray cleaning that also serves as fresh water supply from the storage tank 8h.

Concurrently with the above operation, the branch pipe 1 of the water guide pipe 10a of the first cleaning zone 2A is installed in the evaporation chamber 16.
Cleaning water is sent from 8 to the spray nozzle mechanism 17
At the same time, the hot air is blown into the evaporation chamber 16 through the hot air blowing port 19.

By blowing hot air, the atmospheric temperature in the evaporation chamber 16 is maintained at a high temperature, the amount of water saturation in the air increases, and the cleaning water is turned into a mist and supplied into the room. The evaporation rate is extremely fast, and the generated steam is sent to the exhaust pipe 2 along with hot air.
0, passes through a gas-liquid separator 21, and then is released into the atmosphere. Hot air is economical because waste heat from surface treatment equipment can be used.

In the present invention, since the washing water is evaporated by hot air in the evaporation chamber 16 provided as described above, it is possible to eliminate the amount of drainage or at least significantly reduce the amount of drainage. That is, when the evaporation chamber 16 is provided in the first cleaning zone 2A as in the embodiment, the amount of water that adheres to the object to be treated and is brought in from the preceding chemical zone 1 and the amount of water that is sequentially forwarded from the final cleaning zone 2G. By sending an amount of water corresponding to the difference (surplus amount) from the amount of washing water sprayed into the first washing zone 2A from the branch pipe 18 to the evaporation chamber 16, the amount of water discharged can be completely eliminated. The amount of evaporation can be freely controlled by the amount of spray from the spray nozzle mechanism 17, the amount of hot air blown in, the temperature of the hot air, and the like.

Example Using the present invention, pretreatments of pickling and first to seventh water washing were performed. The object to be treated is a radiator with a width of 530 mm.
It has a height of 350mm, a thickness of 16mm, and a heat dissipation area of ^6m2 , and can process 90 units per hour.

The water supply rate was 320/h, and the water was fed forward from the seventh cleaning zone to the chemical zone in 4/h increments, and sprayed when the object to be treated was pulled up after being immersed. During operation, a direct combustion type deodorizing baking drying oven is used in the evaporation chamber.
70000Kcal/h, from boiler for heating chemical solution
40000Kcal/h, 23400Kcal/h from drain drying oven
While blowing hot air at 110 Nm ³ /min, the cleaning solution in the first cleaning zone was sprayed at 230 Nm 3 /h through the branch pipe using a spray nozzle mechanism.

By operating under the above conditions, the amount of wastewater was reduced to zero. On the other hand, when the plant was operated without hot air supply, the natural evaporation rate was approximately 50/h, and 180/h of waste water was generated.

〔Effect of the invention〕

According to the present invention as described above, it is possible to relatively easily eliminate wastewater or at least reduce the amount of wastewater in the pretreatment that performs multi-stage immersion cleaning, and moreover, it can be carried out economically because waste heat is effectively used. Excellent effects such as

[Brief explanation of drawings]

FIG. 1 is a plan view showing an overview of the immersion type water-saving surface treatment method according to the present invention, FIG. 2 is a circuit diagram showing an implementation apparatus of the present invention, and FIG. 3 is a cross-sectional view showing an example of the evaporation chamber in the present invention. 4 are sectional views showing another embodiment. 1...Chemical solution zone, 2A-2G...Cleaning zone, 8a-8g...Immersion tank, 10a-10g
. . . Water conveyance piping, 11a to 11g . . . Spray nozzle, 16 . . . Evaporation chamber, 17 . . . Spray nozzle mechanism, 19 .

Claims (1)

[Claims] 1. Treating a metal surface with an aqueous solution containing a chemical agent,
Next, in a surface treatment method in which cleaning is performed by immersion in a cleaning water tank, cleaning water is sequentially sent to the previous zone of each zone, and the adhered water is replaced with fresh water in the final zone, and an evaporation chamber is attached to the desired zone. An immersion water-saving surface treatment method characterized in that hot air is introduced into the evaporation chamber while spraying a chemical solution or cleaning water during operation, and the chemical solution or cleaning water is evaporated and discharged together with the hot air. 2. The immersion method according to claim 1, in which the method of sending multiple stages of washing water to the front zone is spraying, and the object to be treated is spray-washed with the washing water before being immersed in the next-stage washing water tank. Water-saving surface treatment method. 3. The immersion type water-saving surface treatment method according to claim 1, which includes a method that uses waste heat from a baking furnace, a drying furnace, a deodorizing device, a chemical solution heating means, etc. as the hot air introduced into the evaporation chamber.