JP2660726B2 - Paint temperature controller - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint temperature adjusting device for adjusting the temperature of paint to a constant temperature.

[Conventional technology]

Generally, in the painting process of automobiles and the like, there is a tendency toward unmanned, that is, fully automatic, and as a part of the process, automatic spray coating using a robot or the like is increasing. In this automatic spray coating, a mist-like paint is sprayed from a nozzle onto a workpiece to be applied. In order to guarantee the coating quality of the coated product, the paint viscosity, spray discharge pressure, discharge time, etc. It is necessary to keep painting conditions constant. Under these coating conditions, there is no problem if the discharge pressure, discharge time, etc. do not change after the initial setting, but the paint viscosity changes due to the temperature change. Therefore, in order to keep this paint viscosity constant,
A paint temperature adjusting device for adjusting the paint to an appropriate constant temperature, that is, a constant temperature, is required.

 Hereinafter, a conventional example of this device will be described with reference to the drawings.

As shown in FIG. 5, this apparatus is a paint pipe for sending paint from an external paint tank T via a valve S and a pump P to an automatic painting robot L for painting a workpiece W such as an automobile in a painting booth B. 1, a heat exchanger 2 is provided, and a water supply pipe 2a of the heat exchanger 2 is provided with a flow control valve (throttle valve) 3. The water supply pipe 2a has a hot water pipe 4b for sending hot water from the hot water tank 4 to the heat exchanger 2 via the hot water pump 4a, and a cold water pipe 5b for sending cold water from the cold water tank 5 to the heat exchanger 2 via the cold water pump 5a. Are connected to a drain pipe 2b of the heat exchanger 2, a hot water pipe 4c for returning the hot water through the heat exchanger 2 to the hot water tank 4, and a hot water pipe 4c for returning the cold water through the heat exchanger 2 to the cold water tank 5. It is connected to the cold water pipe 5c. The hot water tank 4 and the cold water tank 5 are provided with a heater 4d and a cooler 5d, respectively. The hot water pipes 4b and 4c are provided with hot water solenoid valves 6 and 7, respectively, and the cold water pipes 5b and 5c are provided with cold water solenoid valves 8 and 9, respectively.

A paint temperature sensor 10 for detecting the temperature of the paint is provided on the outlet side of the heat exchanger 2 of the paint pipe 1. A setting device (PID controller) 11 for controlling the hot water 3 and a switching device 12 for operating the hot water solenoid valves 6, 7 and the cold water solenoid valves 8, 9 to switch between hot water and cold water sent to the heat exchanger 2.
It has. In the figure, 6a, 7a, 8a, 9a, 10a, 11a, and 12a are signals.

It may be considered that the paint temperature before the heat exchange is substantially equal to the outside air temperature. The change in the outside air temperature is represented by a curve N as shown in FIG. I draw between. This is an average pattern, although there is a difference between summer and winter, so the paint temperature also changes.

If the paint temperature is lower than the set temperature (25 ° C) (second
In the region C in the drawing), the coating material is heated by the heat exchanger 2 in order to reach the set temperature. In other words, the hot water solenoid valve
6, 7 and the flow control valve 3 are opened, and the hot water pump 4a operates to circulate the hot water in the hot water tank 4 through the heat exchanger 2 to increase the paint temperature. When the paint temperature reaches the set temperature, the flow control valve 3 is closed. Conversely, when the paint temperature is higher than the set temperature (25 ° C.) (region H in FIG. 2), the paint is cooled by the heat exchanger 2 in order to reach the set temperature. That is, the electromagnetic valves 8 and 9 for chilled water and the flow control valve 3 are opened, and the chilled water in the chilled water tank 5 is caused to flow through the heat exchanger 2 by the operation of the chilled water pump 5a to lower the paint temperature. When the paint temperature reaches the set temperature, the flow control valve 3 is closed.

The operation of the flow control valve 3 is reversed when supplying hot water shown in FIG. 3 and when supplying cold water shown in FIG. That is, when the paint temperature rises during hot water supply (region C in FIG. 2), the valve body of the flow control valve 3 rotates in the m direction and closes the flow control valve 3, but during cold water supply (first 2
When the paint temperature rises in the region (H in the figure),
The valve body of the flow control valve 3 rotates in the l direction to open the flow control valve 3. Therefore, it is necessary to switch the control of the setting device 11 for controlling the flow rate control valve 3, and the switching of the setting device 11 is also performed by the switching device 12 for switching between the hot water solenoid valves 6 and 7 and the cold water solenoid valves 8 and 9. . The operation of the switch 12 has been manually performed by an operator who has heard the alarm issued at the switching temperature, confirming and judging the temperature of the outside air.

Further, as a device for adjusting the paint viscosity which affects the paint quality, there is a "coating device" disclosed in JP-A-63-12363. This device senses the temperature inside the coating booth and uses the temperature to determine the amount of solvent. This is to adjust the paint viscosity by making adjustments.

[Problems to be solved by the invention]

However, according to the above conventional technique, there are the following problems.

a) In the above-mentioned conventional paint temperature control apparatus, since the operator manually operates the switch 12 for switching the control of the hot water and the cold water and the control of the flow rate control valve 3 based on the temperature of the outside air, it is artificial. Misjudgment may occur. Further, it is necessary to perform the operation several times a day, which is complicated and time-consuming. And it is a factor that hinders unmanned operation, that is, complete automation, in a painting factory where unmanned operations are advanced.

b) In the above-mentioned coating apparatus, the amount of the solvent is changed according to the temperature in the coating booth to adjust the viscosity of the coating. Therefore, the amount of the solvent is too large or too small with respect to the pigment. Occurs at high risk. In addition, fine adjustment is required, and complicated equipment is required, which is expensive.

The present invention has been made in view of the above-mentioned problems, and can eliminate an artificial judgment error, does not require labor, and can reduce the risk by suppressing the occurrence of coating defects, does not require fine adjustment, In addition, it is an object of the present invention to provide a paint temperature control device that can be safely automated.

[Means for solving the problem]

In order to solve the above problems, the present invention provides a heat exchanger in a paint pipe, a flow control valve in a water supply pipe of the heat exchanger, and a hot water pipe from a hot water tank and a cold water from a cold water tank in the water supply pipe. Connect the pipes, connect the hot water pipe to the hot water tank and the cold water pipe to the cold water tank to the drain pipe of the heat exchanger, and install the solenoid valves for hot water in both the hot water pipes. A solenoid valve for cold water is provided in the cold water pipe, and a paint temperature sensor for detecting the temperature of the paint is provided at the heat exchanger outlet side of the paint pipe.The solenoid valve for hot water and the solenoid valve for cold water are operated to operate hot water. And a cold water, and a paint temperature adjusting device for controlling the flow rate control valve based on the temperature detected by the paint temperature sensor to adjust the temperature of the paint to a constant temperature. A controller for hot water that controls the solenoid valve and the flow rate control valve, a controller for cold water that controls the solenoid valve for cold water and the flow rate control valve, and a comparison between the outside air temperature from the outside air temperature sensor and the set temperature of the paint. And a controller for controlling the temperature of the paint and a controller for switching between the controller for cold water and the controller for cold water.

Further, an air pipe for supplying air to the water supply pipe is connected, an electromagnetic valve for air is provided on the air pipe, and operating means for operating the electromagnetic valve for air when switching between the controller for hot water and the controller for cold water is provided. May be provided.

[Action]

According to the present invention, when the outside air temperature from the outside air temperature sensor is lower than the set temperature, the switching unit automatically switches to the hot water controller. The hot water controller controls the hot water solenoid valve and the flow rate control valve. Conversely, if the outside air temperature from the outside air temperature sensor is higher than the set temperature, the switching unit automatically switches to the cold water controller. The chilled water controller controls the chilled water solenoid valve and the flow rate control valve.

Therefore, the hot water and the cold water sent to the heat exchanger are automatically switched, and the temperature of the paint is adjusted to a constant temperature.

In the case of a device having an operation means for operating the electromagnetic valve for air, the electromagnetic valve for air is operated at the time of switching between the controller for hot water and the controller for cold water. The hot or cold water in the water supply pipe and the drain pipe is removed and collected in a hot water tank or a cold water tank.

〔Example〕

 An embodiment according to the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view of a paint temperature adjusting device according to an embodiment of the present invention, and FIG. 2 is a graph showing a change in outside air temperature in one day. FIG. 3 is a sectional view showing an operation state of the flow control valve at the time of supplying cold water, and FIG. 4 is a sectional view showing an operation of the flow control valve at the time of supplying hot water.

The same parts as those in the conventional example shown in FIG.

As shown in FIG. 1, the paint temperature control device A includes an outside air temperature sensor 21 for sensing the temperature of outside air, a control device 30, an air pipe 40, and a solenoid valve 41 for air provided in the air pipe 40. ing.

The outside air temperature sensor 21 is provided on the side of the paint tank T outside the painting booth B, and is connected to the control device 30. The paint temperature sensor 10 is also connected to the control device 30.
The air pipe 40 is connected to the water supply pipe 2a of the heat exchanger 2.

The controller 30 includes a hot water controller 31 for controlling the hot water solenoid valves 6 and 7 and the flow control valve 3, a cold water controller 32 for controlling the cold water solenoid valves 8 and 9 and the flow control valve 3, and a hot water controller. Switching means 33 for switching between the controller 31 and the cold water controller 32; and a paint temperature setting device 34 for setting the temperature of the paint.
And the hot water controller 31 and the cold water controller 32
And an operating means 35 for operating the air electromagnetic valve 41 at the time of switching.

The switching means 33 is a circuit or a mechanism for switching between the controller 31 for hot water and the controller 32 for cold water by comparing the outside air temperature from the outside air temperature sensor 21 with the set temperature (constant temperature 25 ° C.) of the paint temperature setting device 34. When the outside air temperature is lower than the set temperature, the hot water controller 31 is activated. When the outside air temperature is higher than the set temperature, the cold water controller 31 is operated.
32 operates. The switching means 33 is an operating means 35 during switching between the hot water controller 31 and the cold water controller 32.
Is provided, and when the outside air temperature rises or falls and becomes equal to or exceeds the set temperature for a predetermined time, the operating means 35 is operated.

The hot water controller 31 has a function of comparing the detected temperature from the paint temperature sensor 10 with the set temperature of the paint temperature setting device 34 to control the opening and closing and the opening degree of the flow control valve 3. When the temperature is higher than the temperature, as shown in FIG. 3, the valve body of the flow control valve 3 is rotated in the m direction to close the flow control valve 3, and when the detected temperature is lower than the set temperature, the valve of the flow control valve 3 is closed. The body is turned in the opposite direction to the m direction to control the flow
To release. When the detected temperature is lower than the set temperature, when the temperature difference between the detected temperature and the set temperature is large, the opening of the valve body is increased, and when the difference between the detected temperature and the set temperature is small, the opening of the valve body is reduced. I do. Further, the hot water controller 31 operates to open and close the hot water solenoid valves 6 and 7 and also turns on and off the hot water pump 4a.

The chilled water controller 32 has a function of comparing the detected temperature from the paint temperature sensor 10 with the set temperature of the paint temperature setting device 34 to control the opening and closing and the opening degree of the flow control valve 3. When the temperature is higher than the temperature, the valve body of the flow control valve 3 is rotated in the direction l to open the flow control valve 3 as shown in FIG. 4, and when the detected temperature is lower than the set temperature, the valve of the flow control valve 3 is opened. The body is rotated in the opposite direction to the flow control valve 3
To close. When the detected temperature is higher than the set temperature, when the temperature difference between the detected temperature and the set temperature is large, the opening of the valve body is increased, and when the difference between the detected temperature and the set temperature is small, the opening of the valve body is reduced. I do. Further, the chilled water controller 32 operates to open and close the chilled water solenoid valves 8 and 9 and also operates the ON / OFF of the chilled water pump 5a.

The operating means 35 opens and closes the electromagnetic valve 41 for air. When the electromagnetic valve 41 for air is opened, the hot or cold water in the heat exchanger 2 is removed by air, and the hot or cold water is supplied to each hot or cold water. It is returned to the tank 4 or the cold water tank 5.

 In the figure, 21a, 31a, 32a and 40a are signals.

 Next, the operation of the paint temperature adjusting device A will be described.

The controller 30 controls the outside air temperature from the outside air temperature sensor 21 and the set temperature set by the paint temperature setting device 34 (for example, a constant temperature of 25 ° C.).
Compare. If the outside air temperature is lower than the set temperature (region C in FIG. 2), the switching means 33 automatically switches to the hot water controller 31, and the hot water controller 31 operates. The hot water controller 31 opens the hot water solenoid valves 6, 7 and the flow rate control valve 3, and the hot water pump 4a operates to flow hot water in the hot water tank 4 to the heat exchanger 2 for circulation. The flow control valve 3 closes when the temperature detected by the paint temperature sensor 10 rises and becomes higher than a set temperature, and opens when the detected temperature falls and becomes lower than the set temperature. In this state, when the difference between the detected temperature and the set temperature is large, the opening degree of the valve body of the flow rate control valve 3 is controlled so as to flow a large amount of hot water, and when the difference between the detected temperature and the set temperature is small, The opening of the valve body of the flow control valve 3 is controlled to be small so that a small amount of hot water flows. Since the flow control valve 3 is controlled in this manner, the temperature of the paint that has passed through the heat exchanger 2 becomes constant.

When the outside air temperature rises and the set temperature is maintained for a predetermined time, the hot water controller 31 stops the hot water pump 4a, closes the hot water electromagnetic valve 6, and brings the flow control valve 3 into the fully open state. (At this time, the hot water solenoid valve 7 remains open.) Next, the operating means 35 is operated. The air solenoid valve 41 is opened by the operating means 35 and the air pipe 40 is opened.
Supplies air to the heat exchanger 2. The hot water in the heat exchanger 2 and the water supply pipe 2a and the drainage pipe 2b is collected by the hot water tank 4 by this air. Next, the hot water solenoid valve 7 is closed.

If the outside air temperature further rises and the outside air temperature is higher than the set temperature (H region in FIG. 2), the switching means 33
Then, the controller is automatically switched to the chilled water controller 32 and the chilled water controller 32 operates. The chilled water controller 32 opens the chilled water solenoid valves 8 and 9 and the flow control valve 3, and operates the chilled water pump 5 a to circulate the hot water in the chilled water tank 5 to the heat exchanger 2. The flow control valve 3 is closed when the temperature detected by the paint temperature sensor 10 falls below the set temperature and becomes lower than the set temperature, and is opened when the detected temperature rises and becomes higher than the set temperature. In this state, when the difference between the detected temperature and the set temperature is large, the opening of the valve body of the flow control valve 3 is controlled to be large so that a large amount of cold water flows, and when the difference between the detected temperature and the set temperature is small, The opening of the valve body of the flow control valve 3 is controlled to be small so that a small amount of cold water flows.
Since the flow control valve 3 is controlled in this manner, the heat exchanger 2
The temperature of the paint that has passed through is constant.

When the outside air temperature decreases and the set temperature is maintained for a predetermined time, the chilled water controller 32 stops the chilled water pump 5a, closes the chilled water solenoid valve 8, and brings the flow rate control valve 3 into a fully open state. (At this time, the chilled water electromagnetic valve 9 remains open.) Next, the operating means 35 is operated. The air solenoid valve 41 is opened by the operating means 35 and the air pipe 40 is opened.
Supplies air to the heat exchanger 2. With this air, the cold water in the heat exchanger 2 and the water supply pipe 2a and the drainage pipe 2b is collected in the cold water tank 5. Next, the solenoid valve 9 for cold water is closed.

If the outside air temperature further decreases and the outside air temperature is lower than the set temperature (H region in FIG. 2), the switching means 33
Is automatically switched to the hot water controller 31 by
The above operation is repeated.

Therefore, the temperature of the paint is automatically and constantly maintained at the set temperature, and the adjustment of the paint temperature can be completely automated.

In addition, the inside of the heat exchanger 2 and the water supply pipe 2a,
By collecting the hot water and the cold water in the drainage pipe 2b in each of the hot water tanks 4 and the cold water tank 5, the operating cost can be reduced and the efficiency of the heat exchanger can be improved.

 The present invention is not limited to the above embodiment.

〔The invention's effect〕

Since the present invention is configured as described above, the following effects can be obtained.

1) Since the hot water and the cold water sent to the heat exchanger are automatically switched, an artificial judgment error can be eliminated. In addition, the operation for switching between cold water and hot water is not required, and the labor is not required. And unmanned, that is, complete automation can be expected. In addition, compared to a device that changes the amount of solvent according to the temperature inside the coating booth and automatically adjusts the viscosity of the coating, the occurrence of coating defects can be suppressed, the risk can be reduced, and fine adjustment is unnecessary and inexpensive equipment Becomes

2) By removing hot or cold water in the heat exchanger by air, the efficiency of the heat exchanger is improved, and the temperature control of the paint is ensured. Further, the hot or cold water in the heat exchanger and the hot or cold water in the water supply pipe and the drainage pipe are collected in the hot water tank or the cold water tank, so that an energy saving effect is achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a paint temperature adjusting device according to an embodiment of the present invention, and FIG. 2 is a graph showing a change in outside air temperature in one day. FIG. 3 is a sectional view showing an operation state of the flow control valve at the time of supplying hot water, FIG. 4 is a sectional view showing operation of the flow control valve at the time of supplying cold water, and FIG. 5 is an explanatory view showing a conventional example. A: Paint temperature controller, B: Painting booth L: Automatic painting robot, P: Pump S: Valve, T: Paint tank W: Painted object, 1 ... Paint pipe 2 ... Heat Exchanger 2a Water supply pipe 2b Drainage pipe 3 Flow control valve 4 Hot water tank 4a Hot water pump 4b, 4c Hot water pipe 4d Heater 5 Cold water tank 5a Cold water pump 5b, 5c Cold water piping, 5d Cooler 6,7 Solenoid valve for hot water, 8,9 Solenoid valve for cold water 10 Paint temperature sensor 21 Outside air temperature sensor 30 … Control device 31… Controller for hot water 32… Controller for cold water 33… Switching means 34… Paint temperature setting device 35 …… Operating means 40… Air piping 41… Electromagnetic valve for air

Claims (2)

(57) [Claims] A heat exchanger is provided in a paint pipe, a flow control valve is provided in a water supply pipe of the heat exchanger, and a hot water pipe from a hot water tank and a cold water pipe from a cold water tank are connected to the water supply pipe. A hot water pipe to the hot water tank and a cold water pipe to the cold water tank are connected to the drain pipe of the heat exchanger, and a solenoid valve for hot water is provided for both the hot water pipes. A solenoid valve is disposed, and a paint temperature sensor for detecting the temperature of the paint is provided on the heat exchanger outlet side of the paint pipe, and the hot water solenoid valve and the cold water solenoid valve are operated to switch between hot water and cold water. A paint temperature control device that controls the flow rate control valve based on the detected temperature of the paint temperature sensor to adjust the temperature of the paint to a constant temperature, wherein an outside air temperature sensor that detects the temperature of outside air is provided; Flow control A controller for hot water that controls the drain valve, a controller for cold water that controls the solenoid valve for cold water and the flow control valve, and a controller for hot water that compares the outside air temperature from the outside air temperature sensor and the set temperature of the paint. A paint temperature control device comprising a control device comprising a switching means for switching between the controller and the cold water controller. 2. An air pipe for supplying air is connected to the water supply pipe, and an air solenoid valve is provided on the air pipe, and the air solenoid valve is operated when switching between the hot water controller and the cold water controller. 2. The paint temperature adjusting device according to claim 1, further comprising an operation unit.