JPS6143433B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spray type surface pretreatment device.

When forming a film such as painting or plating on metal products, it is essential to pre-treat the base surface by chemically degreasing and converting it. One of the metal surface pretreatment methods is to divide the inside of the tunnel-shaped booth into multiple sections, divide the inside of the spray into multiple zones in each divided zone, and arrange a spray mechanism and liquid tank in each divided zone.
A commonly used method is to spray a chemical solution such as a degreasing agent or a chemical agent while the object to be treated is transported by a conveyor, and then spray washing water in multiple stages below the next zone to wash off the chemical solution.

However, in the conventional spray-type metal surface treatment method, the sprayed chemical solution was stored in a liquid tank and circulated, and fresh water was supplied to each washing tank to prevent the washing water from becoming contaminated. The drawback was that wastewater was generated and expensive wastewater treatment equipment was required.

As a countermeasure for this, patent applications such as Japanese Patent Publication No. 52-27615 and patent applications proposed by one of the inventors of this application (Japanese Patent Application No. 57-204858, Japanese Patent Application No. 57-216182, Japanese Patent Application No. 57-216182,
-216183) method. In these methods, fresh water is supplied to the final stage of the washing zone, the resulting surplus water is sent one after another to the preceding washing zone, and the surplus water in the first stage washing zone is transferred to the chemical spray zone in the preceding stage. In the zone, the chemical solution tank is heated to prevent excess water from forming, the water is evaporated in the chemical zone, and the water is evacuated using a fan. In these methods, the latent heat due to water evaporation is mainly provided by fuel (eg, propane) for heating the chemical tank. This fuel cost is a major expense.

The present invention saves fuel costs by recovering heat from the exhaust gas using a heat pump to heat the chemical tank, and at the same time, recycles and uses water obtained by condensing exhaust steam as washing water to save tap water. The present invention provides a method.

This will be explained with reference to an example. Figures 1 and 2
The figure shows an example in which the present invention is applied to degreasing and chemical conversion coating treatment in metal product painting equipment, where A is a degreasing section, B is a chemical conversion section, C is a painting section, D is a baking and/or drying section, and E is a baking and/or drying section. is a conveyor, and F is a processed object. The degreasing section A and the chemical conversion section B are configured as a tunnel-shaped booth 1, which includes an entrance section 2A, a preliminary degreasing zone 2B, a degreasing zone 2C, a first washing zone 2D, a second washing zone 2E, and a third washing zone (final washing zone). ) 2F, Chemical Zone 2G, 4th Washing Zone 2
H, 5th washing zone 2I, 6th washing zone 2J,
The final water washing zone 2K and the outlet 2L are formed separately, from the preliminary degreasing zone 2B to the final washing zone 2K.
There is a boundary zone 2 for draining between each zone up to
M to 2U are provided.

FIG. 3 is a diagram showing details of the degreasing section (FIG. 1A). In FIG. 3, the chemical formation part (B in FIG. 1) is omitted. The degreasing section has two stages of degreasing zones, while the chemical conversion section has one stage, and the water washing zone of the degreasing section has three stages, while the water washing zone of the chemical formation section has three stages. Except for the four-tier structure, the degreasing section and the chemical forming section have exactly the same equipment and operations, so only the function of the degreasing section will be explained below.

A spray nozzle 3 is installed in each zone from the preliminary degreasing zone 2B to the third washing zone 2F.
B, 3C, 3D, 3E, and 3F are provided, and liquid tanks 6B to 6F are provided at the bottom. Liquid tank 6B~
The liquid in 6F is passed through the discharge pipes 5B to 5F by pumps 4B to 4F to the spray nozzles 3B to 3F, respectively.
Sent to 3F. Liquid tank 6B and liquid tank 6C are connected through pipe 30
and the filters 31, 3
1', a pump 32, and a circulation system 34 comprising an oil and fat floating tank 33 are connected to discharge the degreased oil.

In the degreasing zone 2C, the first water washing zone 2D, and the second water washing zone 2E, a replenishment spray nozzle 8 is installed at the outlet of each zone, that is, from the rear of the spray nozzle in each zone to the boundary zone.
D, 8E, and 8F are arranged. Degreasing zone 2
The replenishment spray nozzle 8D on the outlet side of C is connected to the discharge pipe 5D of the pump 4D by moving backward through the first flushing zone 2D by a bypass pipe 7D, and similarly, the replenishing spray nozzle 8E of the first flushing zone 2D is connected to the bypass pipe 7E. 2nd to the discharge pipe 5E of the pump 4E.
The replenishment spray nozzles 8F of the water washing zone 2E are each connected to the discharge pipe 5F of the pump 4F by a bypass pipe 7F.

Each bypass pipe 7D, 7E, 7F is provided with an electromagnetic control valve (not shown), respectively. The control valve of the bypass pipe 7D is actuated by a signal from a level switch (not shown) provided in the liquid tank 6B of the pre-degreasing zone 2B, and supplies water to the replenishment spray nozzle 8D in such an amount that no surplus water is generated. Similarly, the control valve for the bypass pipe 7E is connected to a novel switch (not shown) provided in the front water tank 6D, and the control valve for the bypass pipe 7E is connected to a level switch (not shown) provided in the front water tank 6E. Automatically controls the amount of replenishment spray water. On the other hand, a fresh water supply spray nozzle 8W is provided at the exit position of the third washing zone 2F, and fresh water is supplied from the pipe 7W. An electromagnetic control valve (not shown) is provided in the middle of the pipe 7W, and is controlled by a level switch (not shown) of the water tank 6F.
The water level of the water tank 6F is always kept constant.

In this apparatus, objects to be processed are suspended on a conveyor E and moved from left to right through each zone of a booth 1, where they are degreased and washed with water. The object to be processed is in degreasing zone 2.
When moving from C to the first washing zone 2D, the first washing zone 2 is preliminarily washed with water spray from the replenishing spray nozzle 8D near the boundary between the degreasing zone 2C and the boundary zone 2N, and drained in the boundary zone 2N.
Enter D. The water in the replenishment spray nozzle 8D falls down and enters the liquid tank 6C. Next, the first washing zone 2D
When moving from the second washing zone 2E to the third washing zone 2E, or from the second washing zone 2E to the third washing zone 2F, the water is preliminarily washed by the replenishment spray nozzles 8E and 8F at the entrances of the boundary zones 2O and 2P, respectively, and then transferred to the next stage. Move. The water from the replenishment spray nozzles 8E and 8F falls down and enters the preceding water tanks 6D and 6E, respectively. In this manner, the washing effect is significantly improved by preliminarily washing the object before moving to the subsequent washing zone. That is, when the object to be treated is moved from the degreasing zone 2C to the first washing zone 2D, if the object is moved with the chemical solution still on it, the water in the first washing zone 2D becomes extremely dirty. When moving to the first washing zone 2D, preliminary washing is performed, and the preliminary washing water enters the liquid tank 6C, so the first washing zone 2
D. The amount of dirt in the washing water is significantly reduced. When moving from the first washing zone 2D to the second washing zone 2E,
The same applies when moving from the second washing zone 2E to the third washing zone 2F. In this way, since there is less dirt in the washing water, it is possible to transfer water from tank 6F to tank 6E.
The amount of water transferred from the water tank 6D to the liquid tank 6C is small, and therefore the amount of water from the fresh water supply spray nozzle 8W is small.

Since water from the replenishment spray nozzle 8D enters the liquid tank 6C, the amount of liquid in the liquid tanks 6C and 6B gradually increases. Conventionally, a chemical heating device is provided in the liquid tanks 6B and 6C, and the chemical liquid is heated to 50 to 60 degrees Celsius with fuel, and the chemical liquid spray from the spray nozzles 3B and 3C measures the evaporation of water at the same time as degreasing, and the replenishment spray nozzle 8
Water equivalent to the amount of water added by D was evaporated. The generated steam is sucked into an exhaust duct 10 by a fan 9 and exhausted. Exhaust duct 10
An eliminator 11 is provided in the middle of the exhaust gas to remove chemical mist contained in the exhaust gas. The removed chemical liquid is returned to the chemical liquid tank through the return pipe 12. Previously, the exhaust gas was simply dumped into the atmosphere. In addition, a large amount of fuel was required to heat the chemical solution.

In the present invention, the exhaust gas exiting the fan 9 is transferred to the heat exchanger 13.
to go into. The heat exchanger 13 is an evaporator of a heat pump, and the exhaust gas and the refrigerant exchange heat. 14 is a heat pump compressor, 15 is a condenser, 16 is an expansion valve, and arrow 17 is the refrigerant circulation direction. The exhaust gas is cooled in the evaporator 13, and the steam condenses into water, which flows through the pipe 18.
It enters the water tank 19 through. The pipe 7W comes out from the water tank 19 and supplies fresh water to the replenishment spray nozzle 8W. That is, the washing water will be circulated through this treatment device. If the water in the water tank 19 decreases, tap water is replenished through the pipe 20, but the amount of tap water used can be extremely small.

The circulation system 34 of the liquid tanks 6B and 6C flows in accordance with the arrow 21 after passing through the flotation tank 33, is heated by the condenser 15 of the heat pump, and returns to the liquid tank 6C. This amount of heating heat sufficiently satisfies the amount of heat required for water evaporation by the spray nozzles 3B and 3C, and no extra fuel is required.

In this way, in the device of the present invention, the exhaust duct 1
The chemical mist is removed from the exhaust gas discharged at 0 in the eliminator 11, and the chemical is returned to the liquid tank 6C. Next, it is cooled in the evaporator 13 of the heat pump to condense the steam and return it to the washing water, and then the heat recovered by the heat pump is It can be used as a heating source for the liquid tanks 6B and 6C. That is, according to the present invention, only a small amount of supplementary tap water and electric power for operating the heat pump are required to be supplied, and it is possible to obtain a metal surface pretreatment device that is completely pollution-free and easy to control.

In the case of metal product painting equipment, there is equipment D for baking and/or drying after painting. Since the exhaust gas of this equipment is naturally high temperature, by mixing outside air into the exhaust gas to adjust the temperature, and then blowing it into the air supply hole 23 of the inlet section 2A through the duct 22, the ambient temperature in the preliminary degreasing zone 2B and the degreasing zone 2C can be adjusted. The water will evaporate sufficiently even if the temperature of the spray liquid is somewhat low. Therefore, there are effects such as the amount of heat recovered by the heat pump being small and the power of the heat pump being small, but these can also be achieved within the scope of the present invention.

As a specific example, when the fresh water from the replenishment spray nozzle 8W is 200/H, that is, the moisture evaporation in the preliminary degreasing zone 2B and the degreasing zone 2C is 200/H.
In the case of /H, the power of the heat pump compressor was approximately 35KW, and 40/H was enough to replenish tap water. In the case of the method of heating the liquid tanks 6B and 6C with fuel, 15 kg/h of propane was required as fuel, and 200 kg/h of tap water was also required.

[Brief explanation of the drawing]

Fig. 1 is a general conceptual diagram of a metal product coating equipment to which a wastewater-free metal surface treatment apparatus according to an embodiment of the present invention is applied; Fig. 2 is a front view of the inlet of the degreasing section shown in Fig. 1;
The figure is a longitudinal sectional side view of the degreasing section of FIG. 1. A...Degreasing section, B...Chemical formation section, C...Painting section, D...Baking and/or drying section, E...Conveyor, F...Workpiece, 1...Booth, 2A...Inlet section, 2B, 2C, 2
G...Medical solution zone, 2D to 2F, 2H to 2K...Washing zone, 2M to 2U...Draining boundary zone, 3B
~3F...Spray nozzle, 4B~4F...Pump,
5B to 5F...Pump discharge pipe, 6B, 6C...Liquid tank,
6D~6F...Aquarium, 7D~7F...Bypass pipe, 8
D~8F...Replenishment spray, 9...Exhaust fan, 10
...Exhaust duct, 11...Eliminator, 13...Condenser, 14...Compressor, 15...Condenser, 16...Expansion valve, 17...Refrigerant circulation arrow, 18...Condensed water return pipe,
19... Water tank, 20... Water pipe, 30... Communication pipe, 3
1, 31'...filter, 32...pump, 33...
Floating tank, 34...Liquid circulation system.

Claims (1)

[Claims] 1 In an apparatus that forms a chemical liquid zone and a multi-stage water washing zone following it in a tunnel-shaped booth, and transfers the processed material through these zones to perform treatments such as degreasing and/or chemical conversion, each zone has a liquid tank. A mechanism is provided to guide and spray chemical solution or washing water from this liquid tank, supply fresh water to the final stage of the washing zone, and send a portion of the water from the final stage to the previous washing zone in sequence, A portion of the water in the water washing zone is sent to the chemical zone, where the water is evaporated by the spray mechanism of the chemical zone and discharged through the exhaust duct.The exhaust air is cooled by the heat pump's refrigerant evaporator and then disposed of. A wastewater-free system characterized by heating the chemical in the chemical zone using the heat generated by condensation, supplying all or part of the heat equivalent to the heat of evaporation of water, and continuing evaporation without or with a small amount of fuel. Surface treatment equipment.