JPH0547273B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention aims to balance the amount of clean air supplied into the booth body and the amount of contaminated air discharged outside the booth body. The booth is designed to prevent contaminated air from leaking from the booth body and from outside air containing dust entering the booth body through the loading and unloading ports for the workpiece that are opened at both ends of the booth body. Regarding the painted paint booth.

[Conventional technology]

Air-conditioning paint booths used for car painting must be installed from air conditioning equipment to prevent paint mist, evaporated organic solvents, etc. that fill the booth body from causing paint film defects and harming the health of workers. Clean air supplied by an air supply fan is introduced into the booth body through a filter at a predetermined wind speed, and at the same time, contaminated air within the booth body is discharged by an exhaust fan.

At this time, if the balance between the amount of clean air supplied and the amount of contaminated air exhausted is disrupted, the contaminated air inside the booth will flow out from the loading/unloading ports for the workpiece that are opened at both ends of the booth, worsening the surrounding environment. Otherwise, outside air containing dust and the like may flow into the booth body, causing paint film defects.

For this reason, in the past, the rotation speeds of the air supply fan and the exhaust fan were previously set to be constant so that the amount of air supply and exhaust within the booth body was equal.

However, in this case, the supply/exhaust balance may be disrupted due to clogging of the filter that introduces clean air into the booth body at a predetermined wind speed, or the supply/exhaust balance may be disrupted due to fluctuations in the number of workpieces being transported within the booth body. The exhaust balance was disrupted, and it was not possible to reliably prevent the outflow of contaminated air or the inflow of outside air.

Therefore, the present applicant has developed a booth by detecting the wind direction and wind speed of the air flowing in and out from the loading/unloading port, and variably controlling the rotational speed of the air supply fan and exhaust fan based on the detected wind direction and wind speed. We prototyped a new paint booth that can balance supply and exhaust inside the main body (see Japanese Patent Application No. 60-63961).

This painting booth is designed to control the direction of the air flowing in and out from the loading and unloading ports for the workpiece that are opened at both ends of the booth body.
It is equipped with a wind speed sensor that detects wind speed (air volume), and a control device that reads the detection signal of the sensor and performs air supply and exhaust control within the booth body based on the updated and stored wind direction and wind speed.

[Problem that the invention seeks to solve]

However, in this case, each time an object to be coated is carried in or taken out from the loading/unloading port, the sensor detects the wind speed of the air that temporarily flows out from the loading/unloading port, which is blocked by the object and the opening area is reduced. The air supply fan and exhaust fan are controlled based on the detected value. A problem has arisen in that unnecessary air supply and exhaust control is performed in response to changes in wind speed, which actually upsets the air supply and exhaust balance.

In other words, while the painting booth is in operation, a slight positive pressure is maintained inside the booth body to prevent dust, etc. that may cause paint film defects from entering the booth body, and the air inside the booth body is kept in a state of positive pressure. Approximately always from the loading/unloading exit
The air supply and exhaust are balanced so that a small amount of air flows out at a wind speed of about 0.1 to 0.25 m/sec. According to the applicant's experimental results, when the speed of the air flowing out from the entrance is approximately 0.25 m/sec and the air supply and exhaust are balanced within the booth body, the workpiece to be coated is placed in the entrance to block it. When the speed of the air flowing out from the loading port increases to 0.34 m/sec, based on the detection signal of the sensor that detected this,
The control device immediately works to increase the exhaust volume of the exhaust fan, increasing the output of the inverter that varies the rotation speed of the exhaust fan from 74% to 74.5% of the normal output, and reducing the wind speed of the air flowing out from the entrance. Although it operates to return to its original state, it has been found that it takes about 4 minutes to converge after the start of this operation until the wind speed at the entrance actually returns to 0.25 m/sec.

Therefore, after the object to be coated has already passed through the entrance, supply/exhaust control is performed in accordance with the change in wind speed when the object to be coated blocks the entrance.
On the contrary, the result was that the air supply and exhaust balance was disrupted.

Therefore, the present invention provides a coating method that can prevent unnecessary air supply and exhaust control from being performed in response to temporary changes in wind speed when objects to be coated are carried in and out, when the supply and exhaust air supply within the booth body is well balanced. The purpose is to provide a booth.

[Means for solving problems]

In order to achieve this object, the present invention includes a sensor that detects the wind direction and wind speed of air flowing in and out from the loading and unloading ports for the objects to be coated, which are opened at both ends of the booth body;
In a painting booth equipped with a control device that controls air supply and exhaust inside the booth body based on the wind direction and wind speed that are updated and stored by reading the detection signal of the sensor, the control device controls whether the object to be coated is at the loading/unloading exit. It is characterized by outputting a control signal to continue air supply and exhaust control based on the wind direction and wind speed stored immediately before the carry-in/out signal is output for a certain period of time when the carry-in signal is output.

[Effect]

According to the present invention, when the objects to be coated are carried in and out from the carry-in/out ports opened at both ends of the booth body, the air supply/exhaust control that was performed immediately before carrying in/out is continued for a certain period of time. This prevents unnecessary air supply/exhaust control in response to temporary changes in wind speed that occur when the object to be coated passes through the loading/unloading port, thereby causing an imbalance in air supply/exhaust.

〔Example〕

Embodiments of the present invention will be specifically described below based on the drawings.

FIG. 1 is a flowchart showing an example of a painting booth according to the present invention, FIG. 2 is a block diagram showing the configuration of a control device thereof, and FIG. 3 is a flowchart showing an example of the operation of the control device.

In the figure, reference numeral 1 denotes the main body of a supply coating booth in which automobile bodies 2 to be coated are continuously conveyed, and has an inlet 1a and an outlet 1b for the to-be-coated articles at both ends.
is formed with an opening.

In this booth body 1, clean air is supplied from an air conditioner 3 to an air supply chamber 5 by an air supply fan 4, and is introduced into a painting room 7 at a predetermined wind speed through a filter 6, and paint mist and evaporation. Contaminated air in the coating chamber 7 containing organic solvents and the like is sucked and discharged from the exhaust treatment chamber 9 through an exhaust duct 10 by an exhaust fan 8.

11a and 11b are loading/unloading exits 1 of the booth main body 1
This is a sensor that detects the wind direction and wind speed of air flowing in and out from a and lb.

12 reads and updates the detection signals of the sensors 11a and 11b, and also stores the stored wind direction,
It is a control device that controls air supply and exhaust in the booth main body 1 based on wind speed, and is composed of a microcomputer having at least an interface circuit 13, an arithmetic processing device 14, and a storage device 15, as shown in FIG. 2, for example. ing.

The interface circuit 13 has the sensors 11a and 11b on its input side, and optically detects the presence of the car body 2 that has arrived in front of the loading/unloading exits 1a and 1b of the booth main body 1, and generates a detection signal (carrying in/out signal). The photoelectric switches 16a and 16b that output
A/D converters 17a, 17b and 18a, 1, respectively
8b.

In addition, on the output side, inverters 21 and 22 that vary the rotational speed of motors 19 and 20 that drive the air supply fan 4 and exhaust fan 8 are connected to the D/A
They are connected via transducers 23 and 24.

The arithmetic processing unit 14 reads data from the sensors 11a, 11b and the photoelectric switches 16a, 16b, performs predetermined arithmetic processing, and operates the air supply fan 4.
outputs control signals CM and CP that adjust the air supply amount and the exhaust amount of the exhaust fan 8.

The storage device 15 stores a program for executing arithmetic processing by the arithmetic processing device 14, and also stores the air supply fan 4 corresponding to the wind direction and wind speed of the air flowing in and out from the loading/unloading ports 1a and 1b of the booth main body 1.
And a wind direction/wind speed-fan rotation speed conversion table for calculating the rotation speed of the exhaust fan 8 is stored.

The wind direction/wind speed - fan rotation speed conversion table is used to balance the air supply and exhaust inside the booth main body 1. For example, when the air inside the booth main body 1 flows out from the loading/unloading ports 1a and 1b, the rotation of the exhaust fan 8 is When outside air flows into the booth body 1, the rotation speed of the exhaust fan 8 is decreased (or the rotation speed of the air supply fan 4 is increased). The data stored therein is experimentally determined so that the amount of air supply and exhaust can be calculated according to the state of air inflow and outflow.

The above is an example of the configuration of the control device 12, and its operation will now be described based on the flowchart shown in FIG.

FIG. 3 shows the processing procedure of the arithmetic processing unit 14. When the paint booth starts operating, it is first determined in step whether the photoelectric switch 16a or 16b is turned on and a detection signal is output. That is, it is determined whether the leading end of the automobile body 2 being conveyed by a conveyor or the like has arrived in front of the entrance 1a or the exit 1b of the booth main body 1.

Then, when the photoelectric switches 16a and 16b are turned off and no detection signal is output, the process moves to step 11 and continuously reads the wind direction and wind speed detected by the sensors 11a and 11b, and stores them in the storage device 15 in step Update and memorize.

Note that the wind speed is determined by averaging the wind speed values continuously detected for 10 seconds, taking into account the time delay when performing air supply and exhaust control, and ignoring high-frequency noise. Updates and stores every second.

Next, the process moves to step 1, and the updated and stored wind direction and wind speed are determined by referring to the wind direction/wind speed-fan rotation speed conversion table stored in advance in the storage device 15.
Supply fan 4 and exhaust fan 8 according to V ₁ and V ₂
The rotation speed is calculated and temporarily stored in a predetermined storage area of the storage device 15 as rotation speed control information.

Then, the process moves to step, and the rotation speed control information stored in the storage device 15 is output as control signals CM and CP to the inverters 21 and 22 via the interface circuit 13 and the D/A converters 23 and 24, and the motor The rotational speed of the air supply fan 4 and the exhaust fan 8 driven by the booth body 1
control to the optimum value that provides a balance between air supply and exhaust air.

In addition, in the step, the photoelectric switch 16a,
When it is determined that 16b is turned on, that is,
The tip of the car body 2 is the entrance 1 of the booth body 1
a or before the exit 1b and interrupts the optical path of the photoelectric switch 16a or 16b, and when it is determined by the detection signals from the switch 16a, 16b that the automobile body 2 is about to be loaded or unloaded. After proceeding to step 1 and setting the software timer of the control device 12, which is a microcomputer, for a certain period of time (for example, 5 minutes), proceeding to step 1, the rotation is performed based on the wind direction and wind speed V ₁ , V ₂ read in the step. Continuously outputs numerical control information as control signals CM and CP.

Next, the process moves from step to step to determine whether or not the software timer is set. If it is not set, the process returns to step; if it is set, the process proceeds to step. In the step, it is determined whether the software timer has timed up or not. If the time has not expired, the step returns to the step and outputs the same control signals CM and CP as the rotation speed control information output last time. If the time has expired, the timer is set in the step. Clear it and return to the step.

In other words, the automobile body 2
Each sensor 11a, 11
The reading of the wind direction and wind speed detected in step b is stopped for a certain period of time set in the software timer, and the rotation speed control information based on the wind direction and wind speed V ₁ , V ₂ read just before the car body 2 is loaded or unloaded is read. Since the control signals CM and CP are continuously output, it takes a certain period of time (in this example, a software timer is set 5 minutes), the rotational speed of the air supply fan 4 and the exhaust fan 8 is
The rotation speed is maintained at the speed that was controlled just before it was loaded or unloaded.

Therefore, the automobile body 2 is located at the loading/unloading port 1a,
It is possible to reliably prevent the air supply and exhaust balance within the booth body 1 from being disrupted due to unnecessary air supply and exhaust control in response to temporary changes in wind speed when passing through the booth body 1b.

Next, FIG. 4 is a flowchart showing another example of the processing procedure of the arithmetic processing unit 14.

In Fig. 4, first step is to select sensor 1.
The wind direction and wind speed detected by 1a and 11b are read and updated and stored in the storage device 15 in steps. Next, the process moves to step, and it is determined whether or not the photoelectric switches 16a and 16b are turned on. If they are turned on, the main processing is temporarily stopped by the switch signals of the switches 16a and 16b, and the interrupt processing consisting of steps and steps is started. starts, and first reads the time signal from the microcomputer in step, updates and stores this in the storage device 15, and then moves to step.

Further, when the photoelectric switches 16a and 16b are not turned on, the process moves from step to step, reads the current time, and subtracts it from the updated and stored time in the step. Then, the process moves to step and checks whether the subtracted value is, for example, 3 minutes or more, that is, after the rear end of the automobile body 2 passes through the optical path of the photoelectric switches 16a, 16b and the switches 16a, 16b are turned off. It is determined whether 3 minutes have elapsed.

In this step, when it is determined that the temporary wind speed change caused by the loading and unloading of the automobile body 2 has naturally come to an end, a period of three minutes has elapsed since the loading and unloading of the automobile body 2. The wind direction and wind speed V ₁ , V ₂ updated and stored in the above step are read out, the rotational speed of the air supply fan 4 and the exhaust fan 8 is calculated based on the wind direction and wind speed, and the calculated rotational speed is stored in the storage device 1 in the step.
5 is updated and stored as rotation speed control information.

Then, the process moves to step, and the rotation control information updated and stored in the storage device 15 is transferred to the inverter 21,
22 as control signals CM and CP to control the rotational speeds of the air supply fan 4 and the exhaust fan 8 driven by the motors 19 and 20 to optimal values that balance the supply and exhaust air within the booth body 1.

Note that if it is determined in step that the 3 minute convergence time has not yet elapsed, the process moves to step and the air supply and exhaust are adjusted based on the rotational speed control information updated and stored immediately before the photoelectric switches 16a and 16b were turned on. Continue control.

Also, in the step, the photoelectric switch 16a
Or if it is determined that 16b is on,
Move directly from the step to the step,
Since the air supply and exhaust gas control continues based on the rotational speed control information updated and stored immediately before the photoelectric switch 16a or 16b is turned on, unnecessary air supply and exhaustion that responds to temporary changes in wind speed when loading and unloading the automobile body 2 is avoided. The negative effect of disrupting the supply/exhaust balance within the booth body 1 due to exhaust control does not occur.

Note that the switch that detects the presence of the automobile body 2 that has arrived at the entrance/exit 1a, 1b of the booth main body 1 and outputs a detection signal is not limited to the photoelectric switch as described above, but any sensor such as a proximity switch may be used. be able to.

Furthermore, the air supply and exhaust control by the control device 12 is not limited to the case where the rotation speeds of the air supply fan 4 and the exhaust fan 8 are variably adjusted at the same time, but may be the case where only one of them is varied.

〔Effect of the invention〕

As described above, according to the present invention, when the supply and exhaust air inside the booth body is in a balanced state,
It is possible to reliably prevent the harmful effect of disrupting the air supply and exhaust balance within the booth body due to unnecessary air supply and exhaust control based on temporary changes in wind speed that occur when the workpieces being carried in and out of the booth block the entrance. It has the excellent effect of

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an example of a painting booth according to the present invention, FIG. 2 is a block diagram of a control device thereof, and FIGS. 3 and 4 are flowcharts showing an example of the operation of the control device. Explanation of symbols, 1...booth main body, 1a...carrying inlet, 1a...carrying out port, 2...automobile body (subject to be coated), 4...air supply fan, 8...exhaust fan, 1
1a, 11b...Sensor, 12...Control device, 1
6a, 16b...photoelectric switch.

Claims (1)

[Claims] 1. Sensors 11a, 11b that detect the wind direction and wind speed of the air flowing in and out from the loading/unloading ports 1a, 1b for the workpieces 2 opened at both ends of the booth body 1, and the detection of the sensors 11a, 11b. In a painting booth equipped with a control device 12 that performs air supply and exhaust control in the booth main body 1 based on the wind direction and wind speed that have been updated and stored by reading signals, the control device 12 controls whether the object 2 to be coated is connected to the loading/unloading port 1a. , 1b and a carry-in/out signal is output, a control signal is output that causes air supply/exhaust control based on the wind direction and wind speed stored immediately before the carry-in/out signal is output to continue for a certain period of time. Painting booth. 2 The control device 12 includes a photoelectric switch 16 that optically detects the presence of the object to be coated 2 immediately before the object to be coated 2 arrives at the loading/unloading ports 1a and 1b and is carried in and out.
The painting booth according to claim 1, wherein reading of the detection signals of the sensors 11a and 11b is temporarily stopped based on the loading/unloading signals output from the sensors 11a and 16b.