JP4392156B2 - Water-based paint coating system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a coating system for water-based recycled paints, and in particular, reliably collects unpainted paints that are generated when the water-based recycled paints are misted and sprayed onto a workpiece to remove them. It is related with the improvement of the coating system for water-based recycle paints which can prevent the outflow of water reliably and can improve the regeneration efficiency of paints.
[0002]
[Prior art]
Conventionally, a work (object to be coated) is continuously conveyed into a painting booth using a conveying means such as an overhead conveyor, and a mist using a paint spraying device (spray nozzle) or the like is applied to the conveyed work. A coating system is widely used in which a paint is sprayed on the surface. In the case where the spraying of the paint by such a spray nozzle is performed, a mist-like unpainted paint floating in the painting booth is generated without being applied to the work in the painting booth. This uncoated paint needs to be prevented from leaking out of the coating booth or reattaching to the work, and it is desired to collect it reliably.
[0003]
As a means for collecting uncoated paint, a method using an air filter or water washing is generally used. Recently, it has been proposed to collect unpainted paint, perform reprocessing such as filtration and color matching, and recycle the paint using the regenerated paint for painting again. Collection of unpainted paint is, for example, a water curtain method in which a collection liquid containing water as a main component is made to flow on the surface of a metal plate installed in a painting booth, or the collection liquid is dispersed in an arbitrary space. Performed by water shower method. The collected liquid entrains a floating uncoated paint, and is then led to a water tank provided at the bottom of the painting booth, where it is circulated and reused in a water curtain, a water shower or the like. When the circulating collected liquid reaches a predetermined paint concentration, it is separated into a concentrate (paint) and filtrate using a UF concentrator (filter device), etc. It is used again for painting, and the filtrate is reused as a collection liquid or cleaning liquid. Such a recyclable paint is referred to as an aqueous recycle paint.
[0004]
On the other hand, in order to efficiently guide the floating uncoated paint to the water curtain or water shower, an airflow that normally flows in a predetermined direction is formed in the coating booth. The formation of the airflow is usually performed by exhausting the atmosphere in the painting booth from an exhaust passage formed at a predetermined position in the painting booth. Specifically, forced exhaust is performed by an exhaust fan arranged on the downstream side (exit side) of the exhaust path. At this time, unpainted paint is mixed in the air in the painting booth that is forcibly evacuated, but the air to be exhausted by arranging a filter for collection on the front side (upstream side) of the exhaust fan The unpainted paint contained in is collected to prevent the unpainted paint from flowing out of the painting booth (outside the system).
[0005]
In addition, uncoated paint collected by the filter for collection should be washed with a water shower from the upper surface of the filter regularly (for example, during lunch breaks, at the end of work, or when changing paint). May be supplied), washed off, transferred to a water tank at the bottom of the booth, and reprocessed together with uncoated paint collected by a water curtain or water shower (see, for example, Patent Document 1 and Patent Document 2) .
[0006]
There is also a structure in which a water shower is provided toward the upstream side (inlet side) of the exhaust path in order to collect uncoated paint before the filter (see Patent Document 3).
[0007]
[Patent Document 1]
JP-A-6-142573 (5th page, FIGS. 1 and 2)
[Patent Document 2]
Japanese Unexamined Patent Publication No. 2000-126659 (5th page, FIG. 1)
[Patent Document 3]
JP-A-9-314025 (page 3, FIG. 1)
[0008]
[Problems to be solved by the invention]
As described above, the filter is refreshed by washing away the unpainted paint collected during the suspension of painting. However, since the cleaning is not performed during the painting operation, if attention is paid during the painting operation, the uncoated paint is gradually accumulated in the filter, causing clogging. When clogging occurs in a part of the filter, the entire cross-sectional area of the exhaust passage is reduced, so that the exhaust flow velocity increases in a portion where no clogging occurs. That is, the negative pressure increases at a position where no clogging occurs, and there arises a problem that uncoated paint particles that have been captured by the conventional filter pass through the filter and come out of the system. Furthermore, there is also a problem that the recycle rate of the water-based recycled paint is reduced due to the outflow of the uncoated paint. Furthermore, since the flow rate of the atmosphere in the painting booth also changes with time, there is a problem that the painting conditions for the workpiece are also varied, resulting in variations in painting quality.
[0009]
If a water shower is installed in front of the filter, the accumulation of uncoated paint on the filter can be reduced, but the adhesion cannot be completely eliminated, and the accumulation of adhesion proceeds little by little. It is impossible to prevent fluctuations in the above, and a similar problem occurs.
[0010]
Although it is conceivable to supply and wash the collected liquid circulating from the upper surface of the filter during the painting operation, the collected liquid also contains paint, and this paint goes out of the system without passing through the filter. This may cause a reduction in the recycling rate of the water-based recycled paint. Furthermore, the evaporation of the collected liquid is accelerated, which increases the overall running cost, which is not preferable.
[0011]
The present invention has been made in view of the above-described conventional problems, and its purpose is to reliably collect uncoated paint, to reliably prevent the uncoated paint from flowing out of the system, and to improve the regeneration efficiency. It aims at providing the coating system for water-based recycle paint which can improve.
[0012]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention collects and recycles the uncoated paint generated when spraying the water-based recycled paint onto the work conveyed in the painting booth. An aqueous recycle paint coating system, provided in a part of the paint booth, for exhausting the atmosphere inside the paint booth to the outside, and disposed in the route of the exhaust path, uncollected unpainted and Rue air filter to block the exit to the outside of Chakutoryo, the paint content of less than 1% of the collecting liquid circulating while collecting non-application paint in the painting booth from the lower surface side of the air filter constantly sprayed toward the lower surface, the Rutotomoni dropped was collected by sprayed absorption liquid mist before reaching the non-application paint floating in the vicinity of the air filter to the air filter, non-attached to the air filter Wash paint A surface spray nozzle, characterized in that it comprises a and a reproducing apparatus for reproducing non-application paint collecting recovered.
[0013]
Here, the coating material content of less than 1% of the collected liquid, for example, can utilize a given concentration following collecting liquid such as circulating while collecting non-application paint in the painting booth.
[0014]
According to this arrangement, the lower surface spray nozzle, since the paint content is constantly sprayed toward to the lower surface of less than 1% of the absorption liquid from the lower surface side of the air filter, non-application paint floating in the vicinity of the air filter Can be collected and dropped by the collected liquid mist sprayed before reaching the air filter, and the uncoated paint floating near the air filter can be collected before adhering to the air filter. In addition, by always spraying the liquid toward the lower surface of the air filter, it is possible to clean the uncoated paint adhering to the air filter, so that the exhaust flow velocity of the air filter can be stably set to a predetermined value based on the air filter performance. Can be maintained. As a result, it is possible to suppress an unnecessarily negative pressure from acting on the unpainted paint, to securely capture and maintain in the air filter and prevent it from being discharged out of the system, and toward the lower surface of the air filter. The uncoated paint captured and maintained by the sprayed liquid can be washed out immediately and easily. As a result, the collection rate and regeneration rate of uncoated paint can be improved. Hereinafter , the “ air filter” is also simply referred to as “filter”.
[0015]
In addition, it is desirable that the spraying of the liquid by the lower surface spray nozzle is performed almost uniformly at a high density throughout the entire filter, and it is preferable that a plurality of the lower surface spray nozzles are arranged at predetermined intervals, for example.
[0016]
In order to achieve the above object, the present invention includes an upper surface liquid supply unit for supplying a filter cleaning liquid from the upper surface of the filter in a state where the exhaust fan is stopped when the paint used is changed in the above configuration. It is characterized by.
[0017]
Here, as the filter cleaning liquid, a dedicated liquid containing no paint or a filtrate having a low impurity content is used.
[0018]
According to this configuration, a small amount of paint remaining on the filter is surely washed away and collected when the paint is changed, so that the collection and regeneration rate of the unpainted paint can be improved and the mixing of the paint after the paint change is also ensured. Can be prevented. Further, for example, when using a collected liquid circulating as a liquid sprayed from the lower surface of the filter, an uncoated paint contained in the collected liquid within a predetermined range remains on the filter, but this residual is also reliably collected. be able to.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention (hereinafter referred to as embodiments) will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating the overall configuration of a water-based recycled paint coating system (hereinafter simply referred to as a coating system) 10 of the present embodiment. The painting booth 12 that constitutes the painting system 10 has an overhead conveyor that suspends and sequentially conveys workpieces 14 (for example, electrical product parts, automobile parts, construction materials, other various mechanical products, daily necessities, etc.) that are objects to be painted. 16 (hereinafter simply referred to as a conveyor) is arranged. The work 14 is carried in from the back side of the paper surface and is subjected to a coating process, and then is carried out to the front side of the paper surface. In addition, a spray nozzle 18 for paint that sprays the water-based recycled paint in the form of a mist on the surface of the work 14 is disposed on the side of the work 14 conveyed by the conveyor 16. The spray nozzle 18 can move in any direction, up, down, left and right, and can spray paint on the entire surface of one side of the workpiece 14 being conveyed. It is to be noted that the paint can be sprayed on the entire periphery of the work 14 as well as on the entire back surface, top surface, bottom surface, and the like by rotating the work 14 while the work 14 is being transported or by turning the spray nozzle 18 upward or downward. A plurality of injection nozzles 18 may be arranged.
[0020]
The water-based recycle paint is a paint that can be used again as a regular paint by collecting the paint that has not been applied to the workpiece and applying a predetermined regeneration process. Can be reused without being cured unless it is dried). Such paints include water-soluble, water-dispersible, or emulsion paints. This water-based recycle paint can be reused after being collected and collected in the painting booth 12 by a liquid used in a water curtain, water shower or the like (for example, a collecting liquid), and then separately concentrated and toned. .
[0021]
As described above, when painting is performed by the spray nozzle 18, after spraying from the spray nozzle 18, there is a mist-like paint (uncoated paint) that floats inside the coating booth 12 without adhering to the work 14. The uncoated paint reattaches to the workpiece 14 after the painting is completed, which causes a quality defect, or adheres to the conveyor 16 and the spray nozzle 18 inside the painting booth 12 and causes a malfunction. Moreover, since the outflow outside the coating booth 12 is not preferable, it is necessary to remove it as much as possible.
[0022]
In the coating system 10 of the present embodiment, a water curtain 20 that collects uncoated paint is formed at a position facing the injection nozzle 18 with the work 14 interposed therebetween. The water curtain 20 includes a curtain forming wall 20a disposed substantially vertically in the painting booth 12, and a liquid supply nozzle 20b for supplying a collecting liquid for collecting uncoated paint to the curtain forming wall 20a. Has been. The curtain forming wall 20a is composed of a metal plate (for example, stainless steel) or resin having excellent corrosion resistance, and the collecting liquid is continuously flowed on the wall surface to form a water curtain, thereby spreading over the curtain forming wall 20a. A water curtain 20 is formed. The collection liquid that forms the water curtain 20 contains water as a main component, entrains a mist-like uncoated paint, and falls downward along the curtain forming wall 20a. In the case of the present embodiment, an air flow is formed in the coating booth 12 by an air flow generated by an exhaust fan, which will be described later, and a mist-like uncoated paint is induced to collide with the water curtain 20 efficiently.
[0023]
An exhaust path 22 for exhausting the atmosphere (air) in the painting area of the painting booth 12 is formed on the back side of the water curtain 20 of the painting booth 12. An exhaust fan 24 is provided in the vicinity of the outlet of the exhaust path 22. A filter 26 is disposed on the upstream side of the exhaust fan 24. By forcibly exhausting the air by the exhaust fan 24, an air flow is generated in the painting booth 12, causing the uncoated paint to collide with the water curtain 20, and the unpainted mist that has not been collected by the water curtain 20. The applied paint is guided to the exhaust path 22 and further to the filter 26. In addition, on the further upstream side of the filter 26 (inlet side of the exhaust passage 22), baffle plates 28 are arranged, for example, in a staggered manner in order to reduce the collection load of the filter 26. In this case, a part of the unpainted paint is also collected on the baffle plate 28 and can be collected later when washed with a cleaning liquid (for example, a collected liquid whose paint content is a predetermined concentration or less). it can.
[0024]
On the bottom surface 12 a of the coating booth 12, a circulating tank 30 into which the collected liquid or the like dropped from the water curtain 20 is input and temporarily stored for circulation of the collected liquid is disposed. The collected liquid flowing into the circulation tank 30 is pumped up by the pump 32 and used again for the water curtain 20. The collected liquid pumped up by the pump 32 by switching the three-way valve 34 is supplied to the nozzle 36 and used as a cleaning liquid for the baffle plate 28. The collected liquid used for cleaning the water curtain 20 and the baffle plate 28 is returned again to the circulation tank 30 to form a circulation system.
[0025]
As described above, the collected liquid that circulates is used for the water curtain 20 and the baffle plate 28, whereby the uncoated paint is gradually accumulated and the concentration increases. Since the collection liquid is intended to collect uncoated paint, it is desirable that the content of the paint is as low as possible. In this embodiment, it is desirable that the paint content of the collected liquid is 1% or less.
[0026]
When the paint concentration of the collected liquid stored in the circulation tank 30 becomes a predetermined concentration, for example, 1% or more, the pump 32 is stopped and the pump 40 is driven to increase the total amount of the collected liquid having a high concentration. Is transferred to a concentration tank 44 constituting the paint recovery system 42. The transferred collected liquid is further transferred to a UF concentrating device (filtering device) 48 by the pump 46 and concentrated and filtered. Then, the concentrate is returned to the concentration tank 44 and the filtrate is transferred to the filtrate storage tank 50. The produced filtrate is pumped up by the pump 52 at a predetermined timing, returned to the circulation tank 30, and used for collecting liquid sprayed on the lower surface side of the filter 26, the water curtain 20, and the baffle plate 28. The Moreover, you may use for the perfect washing | cleaning of the filter 26 at the time of the paint replacement mentioned later.
[0027]
On the other hand, the concentrated liquid concentrated to a predetermined concentration in the concentration tank 44 is pumped up by the pump 54 and transferred to the paint tank 56. After the color adjustment processing (not shown), it is pumped up by the pump 58 and used again as a regenerated paint for painting. .
[0028]
A characteristic feature of this embodiment is that a liquid for collecting uncoated paint (for example, toward the bottom surface of the filter 26 on the lower surface side (exhaust passage inlet side) of the filter 26 disposed in the passage of the exhaust passage 22 (for example, The collected liquid) is being sprayed by the lower surface injection nozzle 60.
[0029]
In the present embodiment, the unpainted paint floating inside the painting booth 12 is collected mainly by the water curtain 20 and the collected liquid forming the water curtain 20 is separated from the wall at the lower end of the curtain forming wall 20a. At the time of leaving, the exhaust fan 24 is sucked into the exhaust passage 22 and sucked into the mist. Further, as described above, collection is also performed by the baffle plate 28. However, there is still unpainted paint that floats without being collected, and moves toward the filter 26 by the suction force of the exhaust fan 24.
[0030]
In the present embodiment, as shown in FIG. 2, for example, the collected liquid is sprayed toward the filter 26 by the bottom surface injection nozzle 60 (a plurality of nozzles are shown in FIG. 2) immediately before the filter 26, so the coating paint m is collected by collecting liquid mist sprayed before reaching the filter 26 falls. The uncoated paint taken in and dropped by the collected liquid mist is landed on the baffle plate 28 and the like, washed away by the cleaning liquid (collected liquid) ejected from the nozzle 36 and guided to the circulation tank 30. At this time, it is desirable that the collected liquid sprayed from the lower surface spray nozzle 60 is densely and uniformly distributed over the entire lower surface of the filter 26, and a plurality of the lower surface spray nozzles 60 are arranged at a predetermined interval, for example. Is preferred. Of course, the number of the lower surface injection nozzles 60 may be one as long as good spraying can be performed on the entire lower surface of the filter 26. Moreover, if the entire surface can be sprayed with a small number of movable nozzles, the equipment cost can be reduced.
[0031]
Even if the uncoated paint m adheres to the filter 26, the collected liquid is always sprayed toward the filter 26, so that the uncoated paint is washed off quickly and easily. Similarly, it is guided to the circulation tank 30 through the baffle plate 28.
[0032]
In this way, by constantly spraying the collected liquid from the lower surface side of the filter 26 toward the lower surface of the filter 26, adhesion of uncoated paint to the filter 26 is suppressed, and if the filter 26 is uncoated Even when the paint has arrived, the filter 26 is always washed from the lower surface side to which the unpainted paint adheres, so that it can be washed off immediately. As a result, the filter 26 is always kept in a washed state, and the ventilation characteristics of the filter 26 can be kept constant in a good state. That is, it is possible to completely prevent the unpainted paint from passing through the filter 26 and to prevent the filter 26 from being clogged, so that the exhaust flow velocity of the filter 26 is stably maintained at a predetermined value based on the filter performance. The air flow in the painting booth 12 does not change. As a result, it is possible to stabilize the coating conditions and the coating state of the paint on the workpiece 14, which can contribute to the improvement of the coating quality of the workpiece. In addition, the paint 26 can be prevented from remaining on the filter 26 and completely prevent the unpainted paint from passing through the filter 26, so that the paint recovery rate can be improved and the aqueous recycled paint can be used with high efficiency. Can do.
[0033]
In FIG. 1, only one circulation tank 30 is shown for simplification of illustration, but when the concentration of paint in the collected liquid exceeds a predetermined value and is completely transferred to the paint recovery system 42, In order to continue collecting uncoated paint, it is preferable to arrange a spare circulation tank for supplying an alternative collection liquid. However, when the processing in the paint recovery system 42 is performed, for example, while the nighttime painting booth 12 is stopped, the configuration of the circulation tank 30 shown in FIG.
[0034]
In general, the painting booth 12 performs painting with various types of paints (different colors and different characteristics). As a result, a paint change operation is required. Therefore, at least two systems such as the circulation tank 30, the paint recovery system 42, the paint tank 56, etc. are prepared in the painting booth 12 for changing the paint, and a circulation system and a regeneration system for each paint are provided using appropriate switching valves. Is preferred. Normally, the collected liquid sprayed on the filter 26 contains a coating material that does not cause inconvenience in collection and cleaning. As a result, the paint may remain on the filter 26 even though the amount is extremely small. When changing the paint, it is preferable to wash the filter 26 with a liquid not containing the paint when changing the paint in order to avoid mixing the paints. For example, as shown in FIG. 3, this cleaning is performed by pumping the filtrate stored in the filtrate storage tank 50 with the pump 52 in a state where the spray of the collected liquid from the bottom spray nozzle 60 is stopped, and the spray nozzle through the valve 62. 64 from the upper surface side of the filter 26. In this case, it is preferable to perform cleaning with a large amount of liquid by making the nozzle diameter of the injection nozzle 64 relatively large. At this time, it is preferable to stop the exhaust fan 24 to prevent vaporization of the filtrate. In this case, since the fluctuation | variation of the whole liquid quantity used in the painting booth 12 can be suppressed, it can also contribute to reduction of the running cost of a painting system.
[0035]
Further, in addition to the cleaning from the upper surface of the filter 26 by the filtrate, the filter 26 can be more satisfactorily cleaned by adopting a configuration in which the filtrate can be ejected from the lower surface injection nozzle 60. Further, as described above, a switching valve may be provided so that the filtrate can be used for cleaning the baffle plate 28.
[0036]
Even if the paint booth 12 is operated using the same paint, when the system is stopped such as at night, the paint contained in the collected liquid sprayed on the filter 26 immediately before the stop adheres to the filter 26 and solidifies. Since it is a water-soluble paint, the remaining solidified paint can be easily removed by spraying the collected liquid again when the system is restarted.
[0037]
The configuration of the coating booth 12 and the configuration of the liquid circulation system shown in the present embodiment are examples, and the liquid is sprayed from the lower surface side of the filter 26 toward the filter 26 at all times during the operation of the coating booth 12 and is not applied. Any configuration that collects the paint and cleans the filter 26 can be changed as appropriate, and the same effect as the present embodiment can be obtained.
[0038]
【The invention's effect】
As described above, according to the present invention, the lower surface spray nozzle continuously sprays a liquid having a paint content rate of a predetermined value or less from the lower surface side of the filter toward the lower surface, thereby floating in the vicinity of the filter. Paint can be collected prior to filter attachment. In addition, by always spraying the liquid toward the lower surface of the filter, even if the uncoated paint reaches the filter and adheres to the filter, the uncoated paint can be quickly removed by washing. The exhaust flow rate can be stably maintained at a predetermined value based on the filter performance. That is, it is possible to suppress an unnecessarily negative pressure from acting on the uncoated paint, and even if the uncoated paint reaches the filter, it can be reliably captured and prevented from being discharged out of the system. As described above, the captured and maintained uncoated paint can be easily washed off with the liquid sprayed immediately toward the lower surface of the filter. As a result, the collection rate and regeneration rate of uncoated paint can be improved.
[Brief description of the drawings]
FIG. 1 is an explanatory view illustrating the configuration of a coating system for aqueous recycled paint according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram for explaining a relationship between a filter provided in an exhaust path of the aqueous recycled paint coating system according to the embodiment of the present invention and a lower surface spray nozzle.
FIG. 3 is an explanatory view for explaining an injection nozzle arranged on the upper surface side of a filter that is preferably applied when changing paint in the coating system for aqueous recycled paint according to the embodiment of the present invention.
[Explanation of symbols]
10 Coating System for Water-based Recycled Paint (Coating System), 12 Coating Booth, 12a Bottom, 14 Workpiece, 16 Overhead Conveyor (Conveyor), 18 Injection Nozzle, 20 Water Curtain, 20a Curtain Forming Wall, 20b Liquid Supply Nozzle, 22 Exhaust Path , 24 Exhaust fan, 26 Filter, 28 Baffle plate, 30 Circulation tank, 32, 40, 46, 52, 54, 58 Pump, 343 way valve, 36 nozzle, 42 Paint recovery system, 44 Concentration tank, 50 Filtrate storage tank, 56 Paint tank, 60 bottom spray nozzle, 62 valve, 64 spray nozzle, m Unpainted paint.

Claims (2)

A water-based recycled paint coating system that collects and recycles uncoated paint generated when sprayed with water-based recycled paint on workpieces transported in the painting booth.
An exhaust passage provided in a part of the painting booth, for exhausting the atmosphere in the painting booth to the outside;
Disposed in the path of said exhaust path, and Rue air filter to prevent the outflow of the non-application paint non collecting external,
A collection liquid with a paint content of 1% or less circulating while collecting uncoated paint in the painting booth is always sprayed from the lower surface side of the air filter toward the lower surface and floats in the vicinity of the air filter. Rutotomoni dropped was collected by collecting liquid mist sprayed before reaching the non-application paint on the air filter, the lower surface spray nozzle for washing the non-application paint adhering to the air filter,
A regenerator that recycles the collected uncollected paint;
A coating system for water-based recycle paint. The system of claim 1, wherein
An aqueous recycle comprising an upper surface liquid supply unit for supplying, as an air filter cleaning liquid, a filtrate generated when the paint is regenerated from the upper surface of the air filter when the exhaust fan is stopped when changing the paint to be used. Paint system for paint.

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