JPH0324264B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of operating a tunnel-type painting booth having an air supply and exhaust system, and particularly relates to a method for operating a tunnel-type painting booth having an air supply and exhaust system, and in particular, a painting booth in which a pretreatment device, a drying oven, etc. are installed in front and behind the painting booth. It is suitable for application to a booth.

[Prior art and its problems]

In general, tunnel-type painting booths are used to prevent paint defects caused by the paint mist that fills the inside of the booth adhering to the object to be painted, as well as from the viewpoint of painting quality control and health and hygiene for workers. Contaminated air is forcibly discharged to the outside through an exhaust device, and conditioned air that has been dust-removed, temperature-controlled, and humidity-controlled is supplied into the booth by an air conditioner.

At that time, if the amount of air supplied into the painting booth and the amount of air exhausted are different, the air flow from the entrance and exit of the painting booth may be different.
External air containing dust and the like flows in, causing paint defects, and contaminated air inside the booth flows out to the outside, worsening the surrounding environment.

For this reason, in the past, the exhaust fan and air supply fan were driven by setting their respective rotational speeds in advance so that the exhaust volume and air supply volume were equal, thereby keeping the paint booth clean and preventing the inflow of outside air. It also prevents contaminated air from flowing out.

However, it is extremely difficult to maintain a balance between exhaust volume and air supply volume.For example, the filter of an air conditioner that supplies conditioned air to a paint booth is
Because it will inevitably become clogged over time,
Even if the intake air amount and the exhaust amount are set constant, only the air intake amount will decrease over time, causing an imbalance between the two.

On the other hand, the conveyance amount and conveyance interval of the object to be coated are as follows:
Each product is different depending on the coating conditions, etc., so for example, if a large amount of objects to be painted are transported at once, the exhaust port will be blocked by the objects to be painted, and only the exhaust volume will be reduced. Unable to maintain balance between the two.

In particular, in painting lines for automobiles, etc., there is a pre-treatment device for degreasing and dust removal of the object to be painted in the front stage of the painting booth, and a drying oven for drying the object to be painted after being painted in the painting booth. Because they are installed in series, if only the supply air volume decreases, air containing chemicals and dust from the pretreatment equipment and hot air from the drying oven will flow into the painting booth, causing chemicals and
Dust and the like adhere to the object to be coated, causing coating defects, and at the same time, the hot air changes the environment inside the coating booth, causing a problem in that uniform coating quality cannot be maintained.

Conversely, if only the exhaust volume decreases, the contaminated air mixed with paint mist and organic solvents in the paint booth will flow into the pretreatment equipment and drying oven.
Pretreatment of the object to be painted is not performed effectively in the pretreatment equipment, resulting in poor adhesion of the paint film, and at the same time, the temperature of the drying oven drops rapidly, causing condensation on the paint film within the drying oven, which ultimately causes coating defects. This causes a problem.

Furthermore, in recent years, from the standpoint of energy conservation, the number of revolutions of the fan in the supply and exhaust system has been reduced to reduce the amount of air supply and exhaust during painting breaks such as during lunch breaks, but in this case as well, the balance between the two has to be kept in mind. If the intake air amount and exhaust amount are not changed while maintaining the same, problems such as contaminated air flowing out through the inlet and the outlet will cause problems such as deterioration of the surrounding environment.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of operating a painting booth that prevents paint defects by preventing air from flowing in and out from the loading and unloading ports, and which does not worsen the surrounding environment. do.

[Structure of the invention]

In order to achieve this objective, the method of operating a painting booth according to the present invention is such that conditioned air is supplied by an air supply fan, and contaminated air is exhausted by an exhaust fan. In a tunnel-type painting booth in which a loading port and a discharge port are formed for loading and unloading objects, the wind direction and wind speed of air flowing into the painting booth or flowing out from the painting booth from the loading port and loading port are detected. , by increasing or decreasing the amount of conditioned air supplied and/or the amount of contaminated air discharged depending on the direction of the air flow, and determining the amount of increase or decrease according to the wind speed,
The present invention is characterized in that air is prevented from flowing into the coating booth and air from flowing out of the coating booth from the carrying-in port and the carrying-out port as much as possible.

[Action of the invention]

According to the method of the present invention, the wind direction and wind speed of the air at the entrance or exit are detected, and the amount of conditioned air supplied or the amount of contaminated air discharged is variably controlled according to the wind direction and wind speed. Therefore, when the system is in an outflow state, the amount of conditioned air supplied is relatively reduced according to the wind speed, and when it is in an inflow state, the amount of conditioned air supplied is relatively increased according to the wind speed. By maintaining the balance between the two, air inflow and outflow from the loading inlet and the unloading outlet are prevented.

〔Example〕

The present invention will be specifically described below based on specific embodiments shown in the drawings.

FIG. 1 is a flow sheet showing a paint booth using the method of the present invention.

In the figure, reference numeral 1 denotes a painting booth, and an inlet 4 and an outlet 5 are formed at the front and rear of the booth for carrying in and out the object 3 to be painted, such as an automobile body conveyed by a floor conveyor 2. A pre-treatment device (not shown) for degreasing and removing dust from the object 3 to be coated is installed in series, and a drying oven (not shown in the figure) for drying the object 3 after painting is installed downstream of the outlet 5. (not shown) are connected in series to form a tunnel shape.

In the coating booth 1, coating devices 6 for coating objects 3 to be coated are arranged at predetermined intervals, and an air supply chamber 7 called a plenum chamber that supplies conditioned air is installed on the ceiling of the booth 1 through a filter 8. arranged,
An exhaust device 9 is disposed on the floor to exhaust contaminated air from within the coating booth 1.

An air supply duct 12 in which an air supply fan 11 is interposed is connected to the air supply chamber 7 to supply conditioned air purified by an air conditioner 10, and the conditioned air supplied from the duct 12 is The paint is supplied to the entire coating booth 1 via the filter 8.

Further, the exhaust device 9 includes a bench lily portion 13 that absorbs and removes paint mist into water, and an exhaust duct 15 in which an exhaust fan 14 is interposed.

Reference numerals 16 and 17 denote a wind speed detector and a wind direction detector that detect the wind speed and direction of the air flow generated at the entrance 3 of the coating booth 1 at predetermined intervals (for example, every 10 seconds) in consideration of the relaxation time.

The wind speed detector 16 is composed of, for example, a hot wire anemometer, and outputs a voltage change due to a change in resistance of a hot wire disposed on the ceiling 3a of the entrance 3 and exposed to an air flow to the control device 18 as a detection signal CV. .

The wind direction detector 17 outputs a detection signal CD to the control device according to the wind direction of the airflow, such as "01" when the air is flowing out, "10" when the airflow is flowing, and "00" when there is no airflow. Output to 18.

The control device 18 outputs a control signal CP that variably controls the rotation speed of the motor 19 of the air supply fan 11 based on the detection signals CV and CD, increases or decreases the amount of air supply of the conditioned air, and increases or decreases the amount of air supplied to the air supply fan 11. By maintaining the balance, air is prevented from flowing in and out from the carry-in port 4 and the carry-out port 5.

FIG. 2 is a perspective view showing an example of the wind direction detector 17.

The wind direction detector 17 includes a rocking plate 20 made of synthetic resin or the like that is rocked by the air flow;
Proximity switches 21R and 2 detect the singing state of
1L, and is fixed to the ceiling 4a of the entrance 4.

The swinging plate 20 has a magnetic body 22 fixed to its upper end, a rotating shaft 23 arranged parallel to the upper edge of the swinging plate 20, and both ends of the rotating shaft 23 having open bottom surfaces. It is supported horizontally by a box-shaped case body 24.

That is, the lower side of the rotating shaft 23 of the swinging plate 20 is exposed and suspended from the case body 24, and is swung by the air flow, and at the same time, the magnetic body 22 at the upper end of the swiveling plate 20 is swung. It is designed so that

The proximity switches 21R and 21L are mounted on a side surface of the case body 24 with a swing plate 2 centered around the rotation shaft 23.
The wind direction of the airflow is detected by detecting the approach of the magnetic bodies 22, which are arranged symmetrically along the arc drawn by the magnetic bodies 22 of 0 and are swung by the airflow. ing.

That is, since the magnetic body 22 is located in the center when there is no airflow, both proximity switches 21R and 21L
Since both are in the off state, "00" is output as the detection signal CD.

Here, when the wind blows from the left to the right (inflow direction) in FIG. 2, the rocking plate 20 tilts to the left, and the magnetic body 2
2 turns on only the left proximity switch 21L, so it outputs "10" as the detection signal CD.

Conversely, when the wind blows from the right to the left in FIG. Outputs "01" as

The control device 18 is configured to output a control signal CP that variably controls the rotation speed of the motor 19 of the air supply fan 11 in accordance with the detection signals CD and CV,
When in the outflow state, the rotation speed of the motor 19 is decreased by a predetermined number of rotations depending on the wind speed, and when in the inflow state, the rotation speed of the motor 19 is increased by a predetermined number of rotations, thereby reducing the feed amount. It increases and decreases to maintain the balance of air supply and exhaust, and prevents air from flowing in and out from the carry-in port 4 and the carry-out port 5.

The control device 18 is composed of a microcomputer having at least an interface circuit 25, an arithmetic processing device 26, and a storage device 27, as shown in FIG. 3, for example.

A wind speed detector 16 that detects the wind speed of the air flow at the entrance 4 of the painting booth 1 is connected to the input side of the interface circuit 25 via an A/D converter 28, and a wind speed detector 16 that detects the wind direction is connected to the interface circuit 25. A detector 17 is connected, and a motor 19 of the air supply fan 11 is connected to the output side of the detector 17 via a D/A converter 29.

The arithmetic processing unit 26 reads the detection signals CV and CD, performs predetermined arithmetic processing, and controls the motor 19.
Outputs a control signal CP that controls the rotation speed of the

The storage device 27 stores a predetermined program for executing the arithmetic processing of the arithmetic processing unit 26.

FIG. 4 is a flowchart showing the processing procedure of the arithmetic processing unit 26. First, in step, the rotation speed n of the motor 19 of the air supply fan 11 is set, and in step, a control signal corresponding to the rotation speed is set.
Output CP.

The motor 30 of the air supply fan 14 is constantly driven to rotate at a predetermined rotation speed corresponding to the rotation speed n of the motor 19 of the air supply fan 11 set in step.

Then, in step, a predetermined period of time (for example, 10 seconds) is set, taking into consideration the time delay until the conditioned air sent by the air supply fan 11 reaches the coating booth 1.
It is determined whether or not the elapsed time has elapsed, and until the elapsed time, the process returns to the step and continues outputting the control signal CP to maintain the rotational speed n of the motor 19.

When a predetermined period of time has elapsed, the process moves to step, and detection signals CV and CD are continuously sent from the wind speed detector 16 and the wind direction detector 17, respectively. Then, the presence or absence of airflow is determined in the step, and since there is no wind when CD = 00, the control signal CP, which is the same as before, is output in order to shift to the step and maintain the current state.
If not = 00, proceed to step and calculate the rotation speed dn that should be varied.

If the wind speed calculated from the detection signal CV is now V, and the areas of the loading port 4 and the loading port 5 are both A, then the wind speed at the loading port 5 is also expected to be V, so the air volume to be increased or decreased is approximately: Required in 2AV.

Also, the rotation speed of the motor 19 to be increased or decreased is dn,
If the air volume that changes depending on the rotational speed dn is dQ, and the current air volume is Q, then the relationship dn/n=dQ/Q holds true.

Here, the air volume Q is given by a function f(n) of the rotational speed n, and since dQ=2AV, the rotational speed dn to be increased or decreased can be found as dn=2AVn/f(n).

Next, in step, the wind direction is judged from the detection signal CD, and when CD=10, since outside air is flowing in, the step moves on to increase the rotational speed n of the motor 19 by replacing n=n+dn.
Return to step and output a new control signal CP.

Also, when CD=01, contaminated air is flowing out, so after moving to step and replacing it with n=n-dn in order to reduce the rotation speed n of the motor 19,
Return to step and output a new control signal CP.

The above is an example of the construction of a painting booth using the method of the present invention.Next, a method of operating the painting booth using the method of the present invention will be described.

First, the floor conveyor 2 is driven to convey the object 3 to be painted, such as an automobile body, and the painting work is started.

At this time, for example, if the filter 8 becomes clogged, only the supply air amount will decrease and the exhaust amount will become relatively larger, resulting in a negative pressure inside the painting booth 1 and the inlet 4 and External air flows in from the pretreatment device and the drying oven via the outlet 5 .

When external air flows in, a detection signal is sent from the wind speed detector 16 and wind direction detector 17 installed at the entrance 4.
CV and CD (=10) are output to the control device 18.

Based on the detection signals CV and CD, the control device 18 outputs a control signal CP to increase the rotation speed of the motor 19 by a predetermined rotation speed in order to increase the supply amount of conditioned air.

Then, when the rotation speed of the motor 19 is increased,
The amount of conditioned air supplied to the painting booth 1 increases and becomes equal to the exhaust amount, preventing the inflow of outside air and allowing the painting booth 1 to exchange air with the outside through the inlet 4 and outlet 5. maintained in a state of no

Conversely, if the amount of conditioned air supplied is greater than the amount of contaminated air exhausted, the contaminated air inside the painting booth 1 will not be completely exhausted and will flow out from the entrance 4 and exit 5. .

When contaminated air flows out, a detection signal is sent from the wind speed detector 16 and wind direction detector 17 installed at the entrance 4.
CV and CD (=01) are output to the control device 18.

Based on the detection signals CV and CD, the control device 18 outputs a control signal CP to reduce the rotation speed of the motor 19 by a predetermined rotation speed in order to reduce the supply amount of conditioned air.

Then, when the rotation speed of the motor 19 is reduced,
The amount of conditioned air supplied to the coating booth 1 is reduced and becomes equal to the amount of exhaust air, thereby preventing contaminated air from flowing out.

In this way, the supply amount of conditioned air is automatically adjusted so that external air containing dust and the like does not flow into the painting booth 1 and that contaminated air does not flow outside.

In addition, in the above embodiment, the wind speed detector 16 and the wind direction detector 17 are arranged only at the loading entrance 4.
Although the case of detecting the wind speed and wind direction of the air flow has been described, the present invention is not limited to this, and the present invention is not limited to this. You can do it like this. At this time, if the wind speeds at the carry-in port 4 and the wind speed at the carry-out port 5 are different, the average wind speed between the two may be determined and the control may be performed based on the average wind speed.

Further, by disposing wind speed detectors 16 at several locations above, below, left and right of the entrance 4 and taking the average value of these, the wind speed can be detected more accurately.

Furthermore, the means for detecting the wind speed and wind direction of the air flow at the outlet 3 is not limited to the above-mentioned wind speed detector 16 using a hot-wire anemometer and the wind direction detector 17 using a swing plate 20, but a conventionally known method. means can be applied.

In addition, in the description of the above embodiment, the air supply fan 11
Although the case has been described in which the supply air amount is variably controlled by controlling the rotation speed of the motor 19, the method of the present invention is not limited to this.
2 may be provided with a damper or the like, and the air supply amount may be adjusted by adjusting the opening/closing angle of the damper.

Further, in the embodiment, only the case where only the intake air amount is variably controlled has been described, but the present invention may also be one that variably controls the exhaust amount or both the air intake amount and the exhaust amount.

〔Effect of the invention〕

As described above, according to the method of the present invention, by detecting the wind speed and wind direction of the air flow at the entrance or exit of the painting booth using a detector, the amount of supplied conditioned air or the amount of exhausted air can be determined. Since it is controlled variably to prevent the inflow and outflow of air from the loading and unloading ports, the amount of air supplied or exhausted may change over time or due to the conveyance status of the objects to be coated. Even in the case of a paint booth, the balance between the two is maintained at all times, which has the effect of preventing dust-laden external air from flowing into the painting booth and preventing painting defects, as well as preventing contaminated air from flowing out. It has the excellent effect of not deteriorating the surrounding environment.

Furthermore, the balance can be maintained at all times even when the supply and exhaust amount is reduced at the same time when painting is stopped.

[Brief explanation of the drawing]

Fig. 1 is a flow sheet showing a painting booth using the method of the present invention, Fig. 2 is a perspective view showing an example of a wind direction detector, Fig. 3 is a block diagram showing an example of a control method, and Fig. 4 is a flow sheet showing an example of a control method. It is a flowchart showing the processing procedure of the microcomputer used. Explanation of symbols, 1...Painting booth, 4...Inlet, 5...Outlet, 7...Air supply room, 11...Air supply fan, 14...Exhaust fan, 16...Wind direction detector, 17 ...Wind direction detector, 18...Control device, 1
9... Motor, 20... Rocking plate, 21R, 21L
...Proximity switch, 22...Magnetic material.

Claims (1)

[Claims] 1 Tunnel-type painting where conditioned air is supplied by an air supply fan and contaminated air is discharged by an exhaust fan, and there are entrances and exits for loading and unloading objects to be coated at the front and rear. In the booth, the direction and wind speed of the air flow flowing into the painting booth or out of the painting booth from the loading port and the loading port are detected, and the supply amount and/or of the conditioned air is determined based on the direction of the air flow. By increasing or decreasing the amount of polluted air discharged and determining the amount of increase or decrease according to the wind speed, the inflow of air into the painting booth and the outflow of air from the loading and unloading ports to the outside of the painting booth can be controlled. A method of operating a painting booth, which is characterized by being designed to prevent the problem as much as possible.