JP2504883B2 - Continuous recovery method of paint sludge - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint sludge continuous recovery method for continuously and efficiently recovering paint sludge generated in a water-washing type coating booth.

[0002]

2. Description of the Related Art In a conventional water-washing type coating booth installed for coating an object to be coated such as an automobile body, for example, as shown in FIG. Part of the paint particles sprayed toward 2
The paint particles that adhere to the object to be coated 2 and become a coating film, and the paint particles that have scattered in the booth 1 pass through the venturi 6 of the water washing device 5 together with the air and the wash water 4 that has overflowed from the gutter 3. Most of them are trapped in water and suspended in a colloidal state. Wash water 4 in this water washing device 5
Is circulated and used by a pipe 8 that connects the water washing device 5 and the storage tank 7, and the suspended paint particles flowing down from the water washing device 5 are supplied into the storage tank 7. Then, the paint particles supplied into the storage tank 7 are settled in the storage tank 7 to be recovered, or the paint particles are collected as a floating material so as to recover the paint sludge. However, since the paint particles suspended in water have an adhesive property, the wash water 4 is circulated through the water washing device 5, the circulation pipe 8, the storage tank 7 and the circulation pipe 8 which constitute the water washing type coating booth 1. It is apt to adhere to and accumulate on the wall surface of the circulation pump 9 or the like, which lowers the cleaning efficiency, and further, the deterioration of the cleaning efficiency deteriorates the ability to capture paint particles floating in the coating booth 1. When the color is changed, the previous paint particles remain, and there is a problem that the coating quality of the article to be coated is significantly adversely affected.

Therefore, conventionally, in order to make the colloidal paint particles dispersed in the washing water non-tacky, hydroxides of alkaline earth metals and amphoteric metals, electrolyte polymers, or inorganic type adsorption such as bentonite and colloidal silica. Addition of an agent, etc., to the washing water causes the non-tacky paint particles to neutralize the interfacial potential in the liquid and agglomerate due to the cohesive force of the colloidal particles, or the cross-linking of the polymeric coagulant When formed, they aggregate and grow into large flocs.
Then, the large flocs precipitate in the storage tank 7 due to the difference in solid-liquid density, or coalesce with bubbles generated during gas-liquid contact in a cleaning device or when pressure is reduced by a pump or the like, and float or float in water.

As a method of recovering the paint sludge in the storage tank 7, the following recovery method has been widely used.

The water in the circulation tank is regularly pumped out and discarded, and the settled sludge is manually collected.

The paint sludge floating on the water surface of the storage tank is taken out from a weir provided in a part of the water tank and continuously collected in the tank.

A collecting method is used in which the settled / floating paint sludge is continuously collected by scraping off with a conveyor.

[0008]

However, the above-mentioned recovery method is incapable of recovering all the sludge in the circulating water, but is incapable of requiring human power, and is not preferable for workers in terms of occupational safety and health. Further, in the above-mentioned collection method, it is premised that the paint sludge of the object to be recovered is settled or floated up.
Instead of ascending, sedimentation / floating / floating is formed at the same time. That is, since the concentration distribution of the paint sludge is formed in the vertical direction in the tank, it is impossible to recover the entire amount of the sludge in the tank, and the recovery efficiency is significantly reduced.

Further, in this recovery method, since the retention time of the washing water in the tank is usually required to be about 10 minutes in order to promote the precipitation or floating in the tank 7, the volume of the tank 7 is There are various problems that the product becomes too large and the storage tank 7 cannot be enlarged.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art.
Forcibly stir by one or more stirrers installed in the tank to make it into a fluidized state, and to establish a dynamic equilibrium state in which the solid content concentration is uniform, and to settle or float the paint sludge as in the past. Instead of expecting a long-time stationary state in a large storage tank to promote it, the feature is that a liquid phase dispersion system with a uniform solid content is obtained. Further, in order to separate the solid content, that is, the coating sludge, from this dispersion system, the wash water is continuously withdrawn, introduced into a separator, and continuously separated and recovered into solid and liquid.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiment shown in FIG. 2. The same parts as the structure of this embodiment and the structure described in the conventional example are designated by the reference numerals used in the conventional example. The description of the same structural parts is omitted.

That is, in the storage tank 7 of this embodiment, two stirring devices 11 for obtaining a uniform liquid phase dispersion system of the solid particles supplied to the storage tank 7, that is, the paint sludge, are installed. ing. The number of stirrers 11 is not limited to two, and may be one or more as required.

Reference numeral 12 is a water supply pump for supplying the paint sludge agitating water in the storage tank 7 to the separation / collection device 14 via the water supply pipe 13. The separation / recovery device 14 is not particularly limited in its mechanism as long as it is a device that can continuously separate water and paint sludge, and examples thereof include a centrifugal separator, a rotary drum vacuum filter, and a filter press. Machines etc. can be selectively used, but in the circulating water, fine colloid particles are generally present together with large particles in the floc state, and although it is a short period of the sludge treatment device, there are problems in daily management. In this case, since sticky flocs or colloidal particles may flow into the separator, in this case,
It is best to use a centrifuge because the filter type may totally block the filter cloth. Reference numeral 15 is a return pipe for returning the separated water separated in the separation / recovery device 14 to the storage tank 7, and 16 is a sludge recovery container for receiving the paint sludge 17 separated in the separation / recovery device 14.

In the above embodiment, the sludge-mixed water in the storage tank 7 is directly supplied into the separation / recovery device 14 by the driving force of the water pump 12, but the present invention is not limited to this, and the storage tank 7 is not limited to this. Concentrator 18 of water mixed with sludge
It may be supplied to the inside and then the sludge mixing concentration of the sludge mixed water is increased to be supplied to the separation and recovery device 14. Reference numeral 19 is a water return pipe for returning the separated water derived from the concentrator 18 to the storage tank 7.

The structure of the present embodiment has been described above. Next, its operation will be described. The paint sludge mixed water supplied from the water washing device 5 into the storage tank 7 is stirred by one or a plurality of stirring devices 11. Since it is agitated by the action and forced into a fluidized state, a uniform liquid phase dispersion system of the paint sludge (solid matter) can be obtained. Therefore, the paint sludge does not settle or float in the storage tank 7, and the paint sludge in the storage tank 7 is supplied to the separation / collection device 14 together with the water by the action of the water pump 12. In the separating and collecting device 14, the paint sludge is effectively separated into water, and as a result, the paint sludge is continuously and effectively collected.

[0016]

As described above, according to the present invention, one or a plurality of agitating devices are installed in a storage tank for storing the water containing paint sludge, which is discharged from the water washing device of the water-washing type coating booth. It is a continuous recovery method of paint sludge in which the water mixed with sludge is stirred and the water mixed with the mixed paint sludge is treated by a separation and recovery device to recover the paint sludge separated from water. The following effects are obtained.

A. By providing one or more agitators in the storage tank, a uniform solid-phase liquid phase dispersion system can be obtained. By introducing this dispersion system into the separation / recovery device, the partial recovery of paint sludge seen in the conventional method can be achieved. Instead, the entire amount of paint sludge can be continuously recovered.

B. The conventional continuous paint sludge recovery system
In the storage tank, the process of "inflow of wash water → retention of wash water → sedimentation / floating / floating of the paint sludge → recovery" is obtained, but the present invention is a process of "inflow of wash water → forced agitation → recovery" -Since the retention process for floating is not required, the capacity of the circulation tank can be greatly reduced. Therefore, the recovery device can be made compact.

C. By using a centrifuge to separate solids in circulating water, particles in a wide range of sizes from large flocs to colloidal particles in water can be stably recovered,
Can be discharged outside the system.

[Brief description of drawings]

FIG. 1 is an explanatory view of a conventional example.

FIG. 2 is an explanatory diagram of an example of the present invention.

[Explanation of symbols]

11 ... Stirrer 12 ... Water pump 13 ... Water pipe 14 ... Separation and collection device 15 ... Return pipe 16 ... Sludge collection container 17 ... Paint sludge 18 ... Concentrator 19 ... Return pipe

Claims (2)

(57) [Claims] 1. A stirrer is provided in a storage tank for storing water containing paint sludge, which is discharged from a water washing device of a water-washing type coating booth, to stir the water containing paint sludge. A method for continuously recovering paint sludge, characterized in that the treated water mixed with the paint sludge is treated by a separation and recovery device to recover the paint sludge separated from water. 2. A stirrer for storing paint sludge mixed water, which is discharged from a water washing device of a water-washing type coating booth, is equipped with one or more stirring devices to stir the paint sludge mixed water. A method for continuously recovering paint sludge, comprising: concentrating the mixed water containing paint sludge by a concentrator, and then treating the concentrated water with a separator / collector to recover the paint sludge separated from water.