JP7250722B2 - Cleaning device and cleaning method for coated object - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus and method for cleaning an object to be coated, and for example, to an apparatus and method suitable for cleaning an automobile body before coating.

Automobile bodies go through degreasing, surface conditioning, and chemical conversion processes, followed by electrodeposition, intermediate coating, and top coating.

Among them, water washing processes for washing automobile bodies exist in various places. Roughly speaking, there are two types of water washing processes, a process of washing with water using a high-pressure shower and a process of soaking in water (DIP).

In the DIP water washing tank, iron scraps, metals, lint, etc., which fall off when the automobile was washed with water, and fine SS and bacteria such as fungi and mold remain and adhere to the surface of the automobile. It causes poor paint quality called "butsu".

As a countermeasure against this, Patent Documents 1 and 2 describe a method of filtering body wash water. In Patent Literature 1, metal powder and the like are separated from metal powder in water by a multi-stage wire mesh filter and centrifugal force. In Patent Document 2, metal powder and the like are removed by a strainer using an amorphous alloy lump and a magnet.

As a filtration device for filtering wastewater, a floating filtration device using a floating filter medium is known, and is commercially available and widely used (for example, Patent Documents 3 and 4, Kurita Water Industries Ltd. light filter (registered trademark)).

JP 2009-112920 A JP-A-10-118423 JP 2004-249165 A Japanese Patent Application Laid-Open No. 2005-262009

In the methods of Patent Documents 1 and 2, dirt adheres to the strainer, requiring cleaning. Centrifugal separation and the like require a large-sized device, are expensive, and require a lot of maintenance. In addition, since the dirt is dispersed in the water, it is necessary to increase the flow rate sent to the filtration device or the like in order to remove the dirt from the entire tank, which requires a larger device and pump.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and method for cleaning an object to be coated, which can efficiently remove SS (suspended solids) from cleaning water with a small flow rate and eliminates the trouble of replacing filters. .

A cleaning apparatus for an object to be coated according to the present invention has a cleaning tank for cleaning the object to be coated, and a float filtering device for filtering water in the cleaning tank and returning filtered water to the cleaning tank.

In one aspect of the present invention, the cleaning bath is a DIP cleaning bath for immersing and cleaning the object to be coated before electrodeposition coating. In addition, an inflow part of a pipe for sending water from the washing tank to the floating filtration device is positioned at one or both of the upper part of the washing tank and the bottom part of the washing tank.

In one aspect of the present invention, the inflow part of the pipe is arranged at or near the outflow part that causes the washing water to flow out from the washing tank. Further, a micro-bubble generating means for generating micro-bubbles is provided in the cleaning tank.

In the cleaning method of the present invention, an object to be coated such as an automobile body before electrodeposition is cleaned using the apparatus for cleaning an object to be coated of the present invention.

According to the present invention, SS in washing water can be efficiently removed by the floating filtration device. In this floating filtration device, the deposits on the floating filter medium can be easily peeled off and removed by washing, so that the operation can be stably continued for a long period of time without replacing the filter.

1 is a configuration diagram of an apparatus for cleaning an object to be coated according to the present invention; FIG. It is a block diagram of a floating filter. It is explanatory drawing of the process of stirring the filter medium of a floating filtration apparatus. It is explanatory drawing of the drainage process from a floating filtration apparatus.

Embodiments will be described below with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view for explaining a cleaning apparatus 1 for objects to be coated according to the present invention.

This washing apparatus 1 for an object to be coated comprises a substantially cylindrical washing tank 2 for washing the object to be coated, and a floating filtering device 5 to which water is supplied from the washing tank 2 through a pipe 3 and a pump 4. , a pipe 6 for returning filtered water from the floatation filtration device 5 to the washing tank 2, and a pipe 7 for discharging filter medium washing drainage from the floatation filtration device 5, and the like.

In this embodiment, the cleaning tank 2 is for DIP cleaning, and cleaning water from the preceding shower cleaning process or the like is supplied through a pipe 8 . Overflow water from the cleaning tank 2 is sent to the next cleaning step through the overflow section 9 .

In this embodiment, the pipe 3 is provided so as to take in water containing SS floating in the washing tank 2 from the upper part of the washing tank 2, and the inflow end of the pipe 3 is an overflow portion 9. or installed in its vicinity. In order to promote floating of the SS in the cleaning tank 2, pressurized water may be supplied into the cleaning tank 2 to generate fine air bubbles.

In the present invention, the water containing the sedimented SS may be taken from the bottom of the cleaning tank 2 and fed to the float filter device 5. You may make it water-supply to the filtering apparatus 5. FIG.

Next, the configuration of the floating filter device 5 will be described with reference to FIG.

A floating filter medium 12 is accommodated in a tower body 11 of the floating filter device 5 . As the floating filter medium, a material having a particle size of about 0.01 to 5 mm and a specific gravity of about 0.02 to 0.95, particularly about 0.02 to 0.5, is usually used. As a material for the floating filter medium, synthetic resins such as polyethylene, pyropropylene, polystyrene, etc., and inorganic foams can be used. The filling amount of the floating filter medium is preferably such that a filter medium layer having a thickness of 0.05 to 1 m, particularly 0.1 to 0.5, is formed in the tower body 11, but is not limited to this.

A lower supply/discharge port 13 is provided at the bottom of the tower body 11, and an upper supply/discharge port 25 is provided at the top. A water supply pipe 14 connected to the discharge port of the pump 4 is connected to the lower supply/discharge port 13 via an inflow valve 15 . The pipe 7 is connected to the lower supply/discharge port 13 via a drain valve 16 . An air communication pipe 17 that rises upward is connected to the middle of the pipe 7 . Reference numeral 18 is a pressure switch.

A water collection nozzle 24 is installed directly below the upper supply/discharge port 25 . One end of the pipe 6 is connected to the upper supply/discharge port 25 . An air inflow pipe 27 is connected to the upper supply/discharge port 25 via a check valve 26 . The check valve 26 allows the flow toward the inside of the tower body 11 and prevents the flow in the opposite direction.

A stirring blade 20 is installed in the tower body 11, and a driving device 22 having a motor 21 for rotating the stirring blade 20 is installed. In this embodiment, the stirring blades 20 are installed with the rotation axis centered vertically and coaxially with the tower body 11 .

When water (raw water) from inside the washing tank 2 is to be filtered by the floating filtration device 5 configured in this manner, the inflow valve 15 is opened, the drain valve 16 is closed, and the raw water from the pump 4 is discharged into the tower. Let it flow into the body 11 . The raw water passes through the layer of the floating filter media 12 and is filtered, passes through the water collection nozzle 24 and is returned to the washing tank 2 from the upper supply/discharge port 25 via the pipe 6 . In this case, the stirring impeller 20 is stopped. The raw water flow LV (linear velocity) at this time is preferably 5 to 100 m/h, particularly 15 to 65 m/h. If it is slower than this range, the amount of treatment will be small.

By continuing the filtration operation, the amount of SS adhering to the floating filter medium 12 increases, and when the pressure loss exceeds a predetermined value, as shown in FIG. 16 is closed, and the driving device 22 rotates the stirring blade 20 to stir the floating filter media 12 in the tower body 11 . As a result, the SS adhering to the floating filter medium 12 is peeled off.

After performing the stirring process for a predetermined time, as shown in FIG. 4, the rotation of the stirring blade is stopped and the drain valve 16 is opened. As a result, the waste water containing the peeled SS flows out through the pipe 7 . At this time, air flows into the tower body 11 via the pipe 27 and the check valve 26 .

The height of the connecting portion between the atmospheric communication pipe 17 and the pipe 7 is substantially the same as the opening height of the lower supply/discharge port 13 on the bottom surface of the tower body 11 . Therefore, the drainage from the inside of the tower body 11 stops when the water level inside the tower body 11 becomes substantially the same as the opening height of the lower supply/discharge port 13 . After the filtering medium washing drainage discharge process is completed, the drainage valve 16 is closed, the inflow valve 15 is opened, and the filtration process shown in FIG. 3 is resumed.

As described above, in this embodiment, the water in the washing tank 2 is filtered by the floatation filtration device 5, so that the SS can be efficiently and sufficiently removed from the washing water in the floatation filtration device 5. FIG. In addition, since the floating filtration device 5 does not require replacement of the filter, and the filter medium can be washed to easily peel off the adhered SS, the filtration operation can be stably continued, and the maintenance is also easy. Easy.

[Comparative Example 1]
The following filter was installed in the DIP water washing tank of the chemical conversion process of automobile body pre-painting treatment, and the filtering effect was verified.
・Cyclone filter ・Back filter ・Magnet immersion

<Experimental conditions>
A comparison was made at a filtration flow rate of 160 L/min.
A micro-air generator was installed in the water washing tank in order to wash the car body efficiently and separate foreign matter from the surface. The amount of air, the direction of air discharge, etc. were constant under each condition, and the conditions were set so that only the removability with the filter could be compared.

<Results>
(1) The cyclone filter can remove large particles such as iron powder, but cannot remove fine particles. Conversely, the back filter can remove fine particles, but the frequency of clogging of the filter is high and requires a lot of man-hours (about once a week).
(2) Immersion of the magnet is effective in removing iron powder, but it cannot remove lint, etc., and in addition, it takes a lot of man-hours to pull up the immersed filter and remove the deposits on the magnet (about once a week). .

[Example 1]
A Kurita Water Industries Ltd. Kurita Light Filter (registered trademark) SA-II was installed as a floating filtration device in the DIP water washing tank of the chemical conversion process for car body pre-painting treatment, as shown in FIG. When washing was performed under the conditions of a washing tank capacity of 43 m ³ , a supply water amount of 160 L/min, and the number of units processed per day of 800 units, the amount of iron powder in the washing water was 0.12 mg/L, and the number of defects at the time of completion of electrodeposition was 93%. (38 cases/vehicle → 2.4 cases/vehicle) were able to be reduced.

Table 1 summarizes the above evaluation results.

REFERENCE SIGNS LIST 1 washing device for object to be coated 2 washing tank 5 flotation filter device 11 tower body 12 flotation filter medium 13 lower supply/discharge port 20 stirring blade 24 water collection nozzle 25 upper supply/discharge port 26 check valve

Claims (6)

a washing tank (2) for washing the object to be coated;
The water in the washing tank (2) is received into the tower body (11) from a lower supply/discharge port (13) provided at the bottom of the tower body (11), and the floating filter medium in the tower body (11) A washing apparatus ( 1) for an object to be coated, having a flotation filtration device (5) for returning filtered water from which SS has been removed from the water by filtration through ( 12) to the washing tank,
The washing tank (2) is a DIP water washing tank for immersing and washing the object to be coated before electrodeposition coating,
A stirring blade (20) for stirring the floating filter medium (12) is provided,
A pipe (3), a pump (4), a water pipe (14) and an inflow valve (15) for feeding the water in the washing tank (2) to the lower inlet/outlet (13) of the float filter (5) ) is provided,
A drainage pipe (7) is connected to the lower supply/discharge port (13) via a drainage valve (16),
An atmospheric communication pipe (17) rising upward is connected to the middle of the drainage pipe (7),
The height of the connecting portion between the atmospheric communication pipe (17) and the drainage pipe (7) is substantially the same as the opening height of the lower supply/discharge port (13) on the bottom surface of the tower body (11). A cleaning device for an object to be coated, characterized by: The inflow part of the pipe (3) for sending water from the washing tank (2) to the flotation filter device (5) is positioned at one or both of the upper part of the washing tank (2) and the bottom part of the washing tank (2). 2. A cleaning apparatus for an object to be coated according to claim 1, characterized in that it is 3. A washing apparatus for objects to be coated according to claim 2, wherein the inflow portion of said pipe ( 3) is arranged at or near an outflow portion for flowing out washing water from said washing tank (2). 4. The apparatus for cleaning an object to be coated according to claim 1, further comprising microbubble generating means for generating microbubbles in said washing tank. 5. A cleaning apparatus for an object to be coated according to claim 4, wherein said fine bubble generating means supplies pressurized water to said cleaning tank in order to promote floating of SS in said cleaning tank. A cleaning method for cleaning an object to be coated using the apparatus for cleaning an object to be coated according to any one of claims 1 to 5.

Images