JP2011110500A - Coating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating system which can make use of exhaust gas from a coating booth effectually. <P>SOLUTION: The coating system 1A includes a coating booth 3, a first wet-type dust collector 4 disposed in parallel with the coating booth 3, and a second wet-type dust collector 5 connected to the first wet-type dust collector 4 with an intermediate duct 63. The first wet-type dust collector 4 washes exhaust gas from the coating booth 3 while circulating water. The second wet-type dust collector 5, which is higher in dust collecting efficiency than the first wet-type dust collector 4, further washes the exhaust gas having passed through the first wet-type dust collector 4. Further, the coating system 1A is provided with a replenishing path 7 for replenishing water in the second wet-type dust collector 5 to the first wet-type dust collector 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a painting system suitable for treating exhaust from a painting booth.

  In the painting booth, spray painting of workpieces is performed. The paint that did not adhere to the workpiece floats in the air as fine particles. Such fine particles are called paint mist. In order not to release the paint mist generated in the painting booth to the atmosphere, it is necessary to properly treat the exhaust from the painting booth. For example, Patent Document 1 discloses a coating system in which a venturi scrubber, which is a wet dust collector, is arranged in a painting booth and the exhaust from the painting booth is cleaned by the venturi scrubber.

  By the way, in the coating system in which the wet dust collector is arranged in parallel in the coating booth as described above, the exhaust from the coating booth is discharged as it is after being washed by the wet dust collector. Since the air supplied to the painting booth is generally prepared by adjusting the outside air to a predetermined temperature and humidity, when such air is discharged outdoors via a wet dust collector, the energy given to the air Will also be discharged. Therefore, it is desirable to effectively use the exhaust from the painting booth.

  Here, for example, Patent Document 2 discloses that a heat exchanger including a heat pipe is provided in an outside air duct and an exhaust duct of a paint drying facility. Specifically, an evaporation unit group of the heat exchanger is provided in the exhaust duct, and a condensation unit group of the heat exchanger is provided in the outside air duct. With this configuration, in the apparatus disclosed in Patent Document 2, heat is transferred from the exhaust gas flowing through the exhaust duct to the external air flowing through the external air duct, and the heat is recovered from the exhaust gas.

JP 2008-188532 A Japanese Patent Laid-Open No. 7-284714

  By the way, the painting mist has various sizes, and the fine coating mist includes a metal dust. However, in the coating system of Patent Document 1, even though a large coating mist can be removed by a wet dust collector, it is not possible to remove a fine coating mist such as paint dust containing metal. For this reason, for example, when the evaporation unit group of the heat exchanger is provided in the exhaust duct as in Patent Document 2 with respect to the coating system of Patent Document 1, paint dust is laminated and attached to the evaporation unit group. Recovery of heat from becomes difficult. That is, in the painting system of Patent Document 1, exhaust from the painting booth cannot be used effectively.

  In view of such circumstances, an object of the present invention is to provide a painting system that can effectively utilize exhaust from a painting booth.

  In order to solve the above problems, the exhaust gas that has passed through the wet dust collector may be further cleaned using a higher performance wet dust collector. However, when a high-performance wet dust collector is simply added, the amount of water used is extremely increased. On the other hand, the inventor of the present invention pays attention to the fact that the exhaust gas cleaned to some extent flows into the high-performance wet dust collector, and cannot reuse the water used in the high-performance dust collector. I thought. The present invention has been made from such a viewpoint.

  That is, the present invention includes a painting booth, a first wet dust collector that is arranged in parallel with the painting booth, and that cleans the exhaust from the painting booth while circulating water, and the first wet dust collector. A second wet dust collector with high dust efficiency, which is connected to the first wet dust collector by a relay duct, and further cleans the exhaust gas that has passed through the first wet dust collector while circulating water. There is provided a coating system comprising a wet dust collector and a supply path for supplying water in the second wet dust collector to the first wet dust collector.

  According to said structure, a big coating mist can be removed with a 1st wet dust collector, and a small paint mist can be removed with a higher performance 2nd wet dust collector. For this reason, it becomes possible to utilize effectively the exhaust which passed the 2nd wet dust collector. Moreover, since the water in the second wet dust collector is supplied to the first wet dust collector by the replenishment path, the water used in the second wet dust collector is reused in the first wet dust collector. Can do. Therefore, the above effect can be obtained while suppressing the amount of water used.

1 is a schematic configuration diagram of a coating system according to a first embodiment of the present invention. The schematic block diagram of the 2nd wet dust collector used for the coating system of FIG. Sectional view taken along line III-III in FIG. The schematic block diagram of the coating system which concerns on 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a coating system 1A according to the first embodiment of the present invention. This painting system 1A has a configuration suitable for an unmanned painting booth (that is, when painting work is performed by a painting robot in the painting booth).

  Specifically, the painting system 1A includes a painting booth 3, a first wet dust collector 4 provided in parallel with the painting booth 3, and a second wet dust collector connected to the first wet dust collector 4 by a relay duct 63. A dust device 5 and an air conditioner (air handling unit) 2 for adjusting the air supplied to the painting booth 3 are provided. Furthermore, the coating system 1A passes through an outside air duct 61 that guides outside air to the air conditioner 2, an air supply duct 62 that guides the air adjusted by the air conditioner 2 to the painting booth 3, and the second wet dust collector 5. And a reflux duct 65 for returning the exhausted air to the air conditioner 2.

  The air conditioner 2 is a device for adjusting the outside air to a predetermined temperature and humidity (for example, a temperature of 28 ° C. and a humidity of 65% in winter and a temperature of 20 ° C. and a humidity of 65% in winter). And a heating coil 23 (for example, a hot water coil and a steam coil) and a warming spray 24 (for example, an electric heater, a steam spray, an ultrasonic humidifier, etc.). In the casing, a blower (blower) 25 is disposed on the downstream side of the steam spray 24, and filters 21 and 26 are disposed on the inlet side and the outlet side.

  The air adjusted by the air conditioner 2 is supplied to the painting booth 3 through the air supply duct 62. The painting booth 3 includes an air supply chamber 31, a painting chamber 32 located below the air supply chamber 31, and an exhaust chamber 33 located below the painting chamber 32.

  The air supply chamber 31 is connected to the fan 25 in the air conditioner 2 via the air supply duct 62, and the air from the air supply duct 62 is sent into the air supply chamber 31 by the fan 25. The supply chamber 31 and the coating chamber 32 are partitioned by a filter in order to change the dynamic pressure of air to a static pressure, and the coating chamber 32 and the exhaust chamber 33 are partitioned by a mesh-structured floor plate. For this reason, the air sent into the air supply chamber 31 by the fan 25 blows through the coating chamber 32 from the top to the bottom.

  Although not shown in the drawing, a painting robot that performs spray painting is arranged in the painting chamber 32, and the work is placed on the floor plate that partitions the painting chamber 32 and the exhaust chamber 33 in a direction perpendicular to the paper surface of FIG. A conveyor is installed for transporting. And if a workpiece | work is conveyed to a predetermined position with a conveyor, spray coating will be performed there with a coating robot.

  The first wet dust collector 4 arranged in parallel to the side of the painting booth 3 has a water reservoir 40 in the lower part, and cleans the exhaust from the painting booth 3 while circulating the water. In the present embodiment, a venturi scrubber having a throat portion 41 that allows exhaust from the coating booth 3 to pass through while being in contact with water is employed as the first wet dust collector 4.

  More specifically, the first wet dust collector 4 has a cleaning chamber 4a communicating with the exhaust chamber 33 of the painting booth 3 through the throat portion 41, and a blower 45 disposed above the cleaning chamber 4a. The cleaning chamber 4 a is separated from the coating chamber 32 by the side wall 42. In other words, the first wet dust collector 4 shares the side wall 42 with the painting booth 3. Further, in the cleaning chamber 4a, a spiral plate that forms a throat portion 41 between the lower end of the side wall 42 is installed in the lower part, and a plurality of eliminators for separating water droplets from the exhaust gas are provided on the upper side. is set up.

  Further, the first wet dust collector 4 has a tub 43 for overflowing water from the upper end of the side wall 42 to the painting booth 3 side, and a pump (not shown) for pumping water from the water reservoir 40 to the tub 43. ing. When the pump is operated, a water curtain is formed on the wall surface of the side wall 42 on the side of the painting booth 3 due to overflow from the eaves 43. The water that forms the water curtain is sucked into the cleaning chamber 4 a together with the exhaust from the coating booth 3 when falling from the lower end of the side wall 42.

  The exhaust gas cleaned by the first wet dust collector 4 is sent to the second wet dust collector 5 through the relay duct 63. The second wet dust collector 5 has higher dust collection efficiency than the first wet dust collector 4, and further cleans the exhaust gas that has passed through the first wet dust collector 4 while circulating water. In the present embodiment, a fine water droplet generator that generates fine water droplets in the air is employed as the second wet dust collector 5. In the second wet dust collector 5, air is ionized by the Leonard effect and is negative. Ions are generated. Here, “fine water droplets” refers to water droplets having a diameter of 1 μm or less. The fine water droplet generator preferably generates a large amount of activated fine water droplets having a diameter of 0.5 μm or less.

  Specifically, the second wet dust collector 5 includes a container 51 that spirally turns the exhaust gas that has passed through the first wet dust collector 4. A water reservoir 50 is formed in the lower part of the container 51, and a chamber 55 connected to the relay duct 63 is provided above the container 51. A water supply pipe (not shown) is connected to the container 51, and water is supplied into the container 51 from a water source (not shown).

  In addition, the second wet dust collector 5 has a cyclone-type gas-liquid separator 5A that separates moisture from exhaust gas containing fine water droplets injected in the container 51, as will be described later. As shown in FIG. 3, one end of the supply pipe 5B is connected to the upper part of the gas-liquid separation part 5A along the tangential direction of the peripheral wall of the gas-liquid separation part 5A. 51 is connected to a slightly upper part of the puddle 50. For this reason, the exhaust gas after swirling spirally in the container 51 is supplied through the supply pipe 5B so as to form a swirling flow in the gas-liquid separator 5A. Further, the lower part of the gas-liquid separator 5A communicates with the water reservoir 50 of the container 51 through the return pipe 5C. For this reason, the water | moisture content isolate | separated from exhaust gas in the gas-liquid separation part 5A is returned to the water sump 50 by the return pipe 5C. Further, the gas-liquid separation unit 5A is provided with a lead-out pipe 5a for leading the exhaust gas from which water has been separated, and a reflux duct 65 is connected to the lead-out pipe 5a.

  As shown in FIGS. 2 and 3, the container 51 includes a circular cylindrical peripheral wall 52 extending in the vertical direction, and a ceiling wall 53 and a bottom wall 54 that block a space surrounded by the peripheral wall 52 from above and below. The ceiling wall 53 is provided with inlets 53a through which the exhaust gas flowing into the chamber 55 flows into the container 51 at equal angular intervals on the same circumference. Further, below each inflow port 53a, a guide plate 53b that is inclined in the same direction as viewed from the center of the container 51 is provided for defining the inflow direction of the exhaust gas from the inflow port 53a to form a swirling flow. ing. In this embodiment, the two inflow ports 53a are provided at intervals of 180 °, and a two-layer swirl flow is formed in the container 51. In the container 51, a support plate 52a for supporting the swirl flow is provided at an appropriate place.

  An injection pipe 56 is installed in the center of the container 51 so as to hang down from the ceiling wall 53, and water is supplied to the inner peripheral surface of the container 51 (more precisely, the inner peripheral surface of the peripheral wall 52). The injection nozzles 57 that generate fine water droplets by colliding with each other are provided so as to be arranged at equal angular intervals on the same plane and vertically with a predetermined pitch.

  Further, the second wet dust collector 5 has a supply path 58 for supplying water from the water reservoir 50 to the injection pipe 56, and the supply path 58 has a pressure of water injected from the injection nozzle 57 (for example, The pump 59 for prescribing 147 kPa to 343 kPa) is provided.

  Returning to FIG. 1, the lower portion of the container 51 is connected to the first wet dust collector 4 by the supply path 7. A pump 71 is provided in the supply path 7, and when the pump 71 is operated, water in the second wet dust collector 5 is supplied to the first wet dust collector 4 through the supply path 7. In the water reservoir 50, paint dust containing metal that has been removed from the exhaust gas by the cleaning by the second wet dust collector 5 is precipitated. Therefore, the upstream end of the supply path 7 is connected to the peripheral wall 52 of the container 51 so that water above the half of the water level of the water reservoir 50 can be extracted. Thereby, relatively clear water is supplied to the first wet dust collector 4.

  In addition, all the water containing the sediment accumulated in the water reservoir 50 may be supplied to the water reservoir 40, and a device for removing the sediment may be provided in a part of the supply path 7.

  Furthermore, in the coating system 1A of the present embodiment, a branch duct 64 for discharging a part of the exhaust gas flowing through the relay duct 63 to the outdoors is branched from the relay duct 63. Further, branch dampers 81 a and 81 b for adjusting the exhaust amount discharged through the branch duct 64 are provided on the downstream side of the branch duct 64 in the relay duct 63 and the branch duct 64.

  The branching dambars 81 a and 81 b of the present embodiment are electrically operated and are connected to the control device 8. The control device 8 is connected to a concentration sensor 83 that detects the concentration of fine particles (solvent) in the coating chamber 32 of the coating booth 3. Then, the control device 8 controls the branch dampers 81a and 81b based on the concentration detected by the concentration sensor 83. Specifically, the branch dampers 81a and 81b are controlled so that the concentration of the fine particles (solvent) in the coating chamber 32 is suppressed to a quarter or less of the explosion limit.

  As the branching dampers 81a and 81b, a fixed variable air volume damper (so-called VD) may be used from an economical viewpoint.

  Moreover, although not shown in the figure, an eliminator (for example, a mist collector manufactured by Sumitomo Bakelite Co., Ltd.) may be used as a means for performing gas-liquid separation by cleaning with the second wet dust collector 5.

  According to the coating system 1A of the present embodiment described above, a large coating mist (for example, fine particles having a diameter of several tens of microns or more) can be removed by the first wet dust collector 4, and the higher performance second wet type. Small dust mist can be removed by the dust collector 5. For this reason, it becomes possible to effectively utilize the exhaust gas that has passed through the second wet dust collector 5. In the present embodiment, by returning the exhaust gas that has passed through the second wet dust collector 5 to the air conditioner 2 by the reflux duct 65, it is possible to reduce energy required for adjustment of the outside air by the air conditioner 2.

  Here, as the second wet dust collector 5, various devices can be adopted as long as the dust collection efficiency is higher than that of the first wet dust collector 4. For example, a large venturi scrubber having a longer gas-liquid contact time than the first wet dust collector 4 may be used. However, if a microscopic water droplet generator that generates microscopic water droplets in the container 51, such as a large amount of activated microscopic water droplets having a diameter of 0.5 μm or less, is used in the container 51 as in the present embodiment, it is collected compared to the venturi scrubber. Dust efficiency is about 3 times higher.

  Further, in the fine water droplet generator, air is ionized in the container 51 to generate negative ions. Negative ions decompose odorous components in the paint mist. Therefore, if a fine water droplet generator is employed as the second wet dust collector 5 as in the present embodiment, an effect of deodorizing the exhaust gas can be obtained.

  Moreover, the activated fine water droplets having a diameter of 0.5 μm or less have the effect of preventing the coating mist from adhering to the container 51 and also have the effect of peeling the coating mist adhering to the container 51. Therefore, the container 51 can be kept clean.

  Further, in the present embodiment, a part of the exhaust is discharged to the outside through the branch duct 64, but the capacity of the amount of exhaust to be processed by the second wet dust collector 5 (depending on the concentration of the solvent). Further, the discharge capacity to the outdoors can be reduced by the processing capacity of the second wet dust collector 5).

<Modification>
As shown in FIG. 1, the exhaust gas is circulated by the reflux duct 65, so that the solvent component is not removed by the wet dust collectors 4 and 5, and thus returned to the coating booth 3. However, if a combustion device (for example, a solvent concentrating device using zeolite or a device for oxidizing and decomposing the solvent) is provided in the middle of the reflux duct 65, a worker in the painting chamber 32 of the painting booth 3 is provided. Can be painted.

  The branch dampers 81a and 81b may be manually operated. In this case, for example, the branch dampers 81 a and 81 b may be adjusted so that about half of the exhaust gas flowing through the relay duct 63 is processed by the second wet dust collector 5.

  Further, the chamber 55 of the second wet dust collector 5 can be omitted, the downstream end of the relay duct 63 is connected to the upper or lower portion of the peripheral wall 52 along the tangential direction of the peripheral wall 52, and the flow velocity from the relay duct 63 is increased. You may make it form a swirl flow using.

(Second Embodiment)
FIG. 4 shows a coating system 1B according to the second embodiment of the present invention. This painting system 1A has a configuration suitable for a manned painting booth (that is, when painting work is performed by a worker in the painting booth). In addition, the same code | symbol is attached | subjected to the same component as 1st Embodiment, and the description is abbreviate | omitted.

  In the present embodiment, the reflux duct 65 (see FIG. 1) is not provided, and instead, an exhaust duct 66 for exhausting the exhaust gas that has passed through the second wet dust collector 5 to the outside is provided. Further, a heat exchanger 9 is provided across the exhaust duct 66 and the outside air duct 61 to exchange heat between the outside air flowing through the outside air duct 61 and the exhaust flowing through the exhaust duct 66. In the present embodiment, the branch dampers 81a and 81b are manually operated.

  The heat exchanger 9 has a primary flow path for flowing outside air and a secondary flow path for flowing exhaust.

  In the present embodiment, energy can be recovered from the exhaust gas by exchanging heat between the exhaust gas and the outside air by the heat exchanger 9. For example, the outside air can be cooled by exhaust when the summer temperature is high, and the outside air can be warmed by exhaust when the winter temperature is low. Other effects are the same as those of the first embodiment.

  Note that the branch duct 64 can be omitted when exhaust is exhausted through the exhaust duct 66 as in the present embodiment.

(Other embodiments)
In FIG. 1 and FIG. 4, the first wet dust collector 4 is juxtaposed on the side of the coating booth 3, but the juxtaposition position of the first wet dust collector 4 is not particularly limited. For example, the first wet dust collector 4 may be arranged in parallel below the painting booth 3.

  The first wet dust collector 4 is not limited to the venturi scrubber that forms the water curtain, but circulates the water (that is, the water that returns to the puddle after the water in the puddle is used for cleaning the exhaust from the painting booth). ) Can be used. For example, a venturi scrubber that circulates water only with an eliminator without using a pump, or a throat section formed by a plurality of pipes in the middle of a flow path for exhaust from the painting booth 3, and the water in the puddle is removed from the throat section. Venturi scrubber sprayed on the surface may be used.

  Further, when the venturi scrubber is used as the second wet dust collecting device 5 in place of the fine water droplet generating device that generates fine water droplets in the container 51, the above-described various venturi scrubbers can be employed.

1A, 1B Coating system 2 Air conditioner 3 Painting booth 4 First wet dust collector (Venturi scrubber)
41 Throat part 5 Second wet dust collector (fine water droplet generator)
DESCRIPTION OF SYMBOLS 50 Puddle 51 Container 52 Perimeter wall 53 Ceiling wall 53a Inlet 55 Chamber 57 Injection nozzle 61 Outside air duct 62 Air supply duct 63 Relay duct 64 Branch duct 65 Recirculation duct 66 Exhaust duct 7 Supply path 81a, 81b Branch damper 9 Heat exchanger

Claims (10)

Painting booth,
A first wet dust collector that is arranged in parallel with the coating booth and cleans the exhaust from the coating booth while circulating water;
A second wet dust collector having higher dust collection efficiency than the first wet dust collector, connected to the first wet dust collector by a relay duct, and the first wet dust collector while circulating water. A second wet dust collector for further cleaning the exhaust gas passing through
A supply path for supplying water in the second wet dust collector to the first wet dust collector;
A painting system.   2. The coating system according to claim 1, wherein the first wet dust collector is a venturi scrubber having a throat portion that allows exhaust from the coating booth to pass through while being in contact with water.   The coating system according to claim 2, wherein the venturi scrubber shares a side wall with the coating booth and forms a water curtain on a wall surface of the side wall on the coating booth side.   The second wet dust collector includes a container that spirally swirls the exhaust gas that has passed through the first wet dust collector, and is disposed in the container so that water collides with an inner peripheral surface of the container. The coating system as described in any one of Claims 1-3 which is a fine water droplet generator which has the injection nozzle which generates a fine water droplet. A puddle is formed in the lower part of the container,
The coating system according to claim 4, wherein an upstream end of the supply path is connected to a peripheral wall of the container so that water above a half of the water level of the water pool can be extracted. The fine water droplet generator further includes a chamber provided above the container and connected to the relay duct,
The coating system according to claim 4 or 5, wherein the ceiling wall of the container is provided with inlets for allowing the exhaust gas flowing into the chamber to flow into the container at equal angular intervals on the same circumference. Branching from the relay duct, further comprising a branch duct for discharging part of the exhaust flowing through the relay duct;
The branching damper for adjusting the exhaust_gas | exhaustion amount discharged | emitted through the said branch duct is provided in the downstream and the said branch duct from the position where the said branch duct in the said relay duct branches. The coating system as described in any one. An air conditioner for adjusting the air supplied to the painting booth;
A reflux duct for returning the exhaust gas that has passed through the second wet dust collector to the air conditioner;
The coating system according to claim 7, further comprising: A concentration sensor for detecting the concentration of fine particles in the coating booth;
The coating system according to claim 8, wherein the branch damper is electrically driven and is controlled based on a concentration detected by the concentration sensor. An air conditioner for adjusting the air supplied to the painting booth;
An outside air duct for guiding outside air to the air conditioner;
An exhaust duct for exhausting the exhaust gas that has passed through the second wet dust collector;
A heat exchanger for exchanging heat between the outside air flowing through the outside air duct and the exhaust flowing through the exhaust duct;
The coating system according to claim 1, further comprising:

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