TWI748003B - Coating and drying device and coating and drying method - Google Patents

Abstract

The coating and drying device that continuously conveys the steel strip on one side and coats the other side and performs drying treatment includes: a conveying part for conveying the aforementioned steel strip; and a coating part for coating the steel strip being conveyed with paint containing organic solvents. ; Oven, drying/baking the steel strip in the heating space on the downstream side than the coating position; exhaust part to exhaust the heating space; concentration measuring part to measure the organic solvent in the heating space Concentration of organic solvent; and a control section to control the operation of the coating drying device. The control section calculates the predicted concentration based on the organic solvent concentration measured by the concentration measurement section, and when the predicted concentration reaches a predetermined threshold concentration or more Carry out the following control: continue the conveyance by the conveying department and stop the painting by the coating department.

Description

Coating drying device and coating drying method

Invention field

The present disclosure relates to a coating drying device and a coating drying method that continuously convey a steel strip while coating and drying.

Background of the invention

In the past, an apparatus for coating a steel strip (metal strip) with a roll coater has proposed a coating drying device that conveys the steel strip while drying/baking the paint applied to the steel strip in an oven, and The method (see, for example, Patent Documents 1-3).

In the coating drying device of Patent Documents 1-3, the inside of the oven is constantly exhausted by a fixed amount by a blower, and the temperature of the steel strip entering the oven rises as it enters the depths, and the coated paint is dried. Approximately in the oven, the full amount of paint will dry and enter the baking step.

Advanced technical literature

Patent literature

[Patent Document 1] Japanese Patent Laid-Open No. 4-193371

[Patent Document 2] Japanese Patent Laid-Open No. 2005-262132

[Patent Document 3] Japanese Patent Laid-Open No. 8-38855

Summary of the invention

However, as in the coating drying device disclosed in Patent Documents 1 and 2, the paint applied to the steel strip usually contains a flammable organic solvent, and the evaporated organic solvent will diffuse into the ambient air in the oven. In order to prevent the components of the organic solvent from burning due to the heat in the oven, the following technical development is also sought: the concentration of the organic solvent in the ambient gas in the oven can be maintained below a predetermined concentration, and by accurately achieving such a control, the improvement It is safe, and can realize energy-saving achieved by optimizing the exhaust volume.

However, in actual operation, sometimes due to human error during the operation of the coating drying device, or malfunction of the control device that controls the coating amount, there is an error from the start of the operation, and the coating amount is too much to double or more. In this case, the ambient gas with a high concentration of organic solvents cannot be completely discharged, which may cause an explosion accident.

On the other hand, as in Patent Document 3, there is also an invention that increases the exhaust volume according to the organic solvent concentration in the oven. However, in order to exhaust the ambient gas with excessive organic solvent concentration as soon as possible, a large blower is required, which increases the production cost. , And also requires a large installation space.

The present disclosure is to solve the aforementioned problems, and its purpose is to improve the safety of the coating drying device and the coating drying method and to save energy during operation.

The coating drying device of one aspect of the present disclosure is a coating drying device that continuously conveys the steel strip on one side, and paints and dries on the other side. It includes: a conveying part for conveying the aforementioned steel strip; The loading position applies paint containing organic solvents to the steel strip being conveyed; an oven forms a heating space for drying the steel strip on the downstream side than the coating position; the exhaust part uses To exhaust the heating space; a concentration measuring unit to measure the organic solvent concentration of the organic solvent in the heating space; and a control unit to control the operation of the coating drying device, the control unit to determine based on the concentration The concentration of the aforementioned organic solvent measured by the part is calculated to reach the predicted concentration, and when the predicted reached concentration is above the predetermined threshold concentration, the following control is performed: continue the conveying by the conveying part and stop the coating by the coating part .

According to the foregoing configuration, control can be performed to prevent the concentration of the organic solvent in the heating space from becoming too high, and the organic solvent can be accurately prevented from burning due to the heat of the heating space, and safety can be improved.

In the coating drying device, the control unit may not only stop painting by the coating unit when the predicted arrival concentration is equal to or higher than the threshold concentration, but also control to slow down the conveying speed of the conveying unit. Thereby, the increase in the concentration of the organic solvent can be further suppressed, and the safety can be further improved.

The coating drying device may be further provided with a removing part that removes the paint applied to the steel strip by the coating part on the upstream side of the heating space, and the control part predicts the arrival When the concentration is equal to or higher than the aforementioned threshold concentration, in addition to stopping the coating performed by the aforementioned coating section, control is also performed to remove the coating material by the aforementioned removing section. Thereby, the increase in the concentration of the organic solvent can be further suppressed, and the safety can be further improved.

In the aforementioned coating drying device, the aforementioned control unit may also perform the following control when the predicted arrival concentration is equal to or higher than the aforementioned threshold concentration: while maintaining the exhaust gas volume of the exhaust unit at the same amount, the aforementioned coating unit is stopped. Painting in progress. In this way, simple control and mechanism implementation can be achieved.

One aspect of the coating and drying method of the present disclosure is a coating and drying method in which the steel strip is continuously conveyed and coated and dried on the other side. It includes: a conveying step, conveying the aforementioned steel strip; The steel strip being transported is coated with a coating containing an organic solvent; the drying step is to dry the steel strip in the heating space on the downstream side than the coating position; the exhaust step is to exhaust the heating space; the measurement step , Measuring the organic solvent concentration of the organic solvent in the heating space; calculating step, calculating the predicted concentration based on the measured organic solvent concentration; and stopping the painting step, when the predicted reaching concentration is above a predetermined threshold concentration At the same time, while continuing the conveyance of the aforementioned steel strip, the painting is stopped at the same time.

According to the aforementioned configuration, it is possible to perform control to prevent the concentration of the organic solvent in the heating space from becoming too high, and it is possible to reliably prevent the organic solvent from burning due to the heat of the heating space, and improve safety.

In the foregoing coating drying method, in the coating stopping step, the predicted arrival concentration is greater than or equal to the threshold concentration. At this time, in addition to stopping the painting, the step of slowing down the conveying speed of the aforementioned steel strip may also be included. Thereby, the increase in the concentration of the organic solvent can be further suppressed, and the safety can be further improved.

In the aforementioned coating drying method, in addition to stopping the coating, the step of stopping coating when the predicted arrival concentration is above the threshold concentration may also include the following step: on the upstream side of the heating space, in the coating The step of removing the aforementioned paint applied to the aforementioned steel strip. Thereby, the increase in the concentration of the organic solvent can be further suppressed, and the safety can be further improved.

In the coating drying method, the coating stopping step may also stop the coating while maintaining the exhaust gas volume at the same amount when the predicted arrival concentration is equal to or higher than the threshold concentration. In this way, simple control can be implemented.

According to this disclosure, safety can be improved.

2: Coating drying device

4: Transport Department

6: Painting Department

6a: With paint roller

6b: Coating roller

6c: Paint storage part

6d: mobile mechanism

7: Painting position

8: Oven

9: Heating space

10: Exhaust section

10a: Catheter

10b: Blower

12: Concentration measurement department

14: Control Department

16: Idling section

18: Evaporation

20: Evaporation

22: End of evaporation

23: dry area

24: Evaporation

25: Baking area

26: Evaporation

27: Evaporation

28: Evaporation

29: End of painting

30: Coating drying device

31: Motor

32: End of evaporation

34: Evaporation

36: Evaporation

40: Coating drying device

42: Removal part

43: Receiving plate

44: End of evaporation

46: Evaporation

47: Evaporation

48: Finishing point of painting

A: Transport direction

D1: Actual average concentration

D2: Determine the concentration

D3: reach the predicted concentration

D4: Cutoff concentration

S: Steel belt

P: Maximum

t0: start time of operation

t1: Elapsed time from the start of painting

x: Variables including the delay time until the organic solvent flows in

T: time constant

Fig. 1 is a schematic configuration diagram showing the coating drying device of the first embodiment.

Fig. 2A is a schematic diagram illustrating an example of the operating state of the coating drying device of the first embodiment.

Fig. 2B is a schematic diagram illustrating an example of the operating state of the coating drying device of the first embodiment.

Fig. 2C is a schematic diagram illustrating an example of the operating state of the coating drying device of the first embodiment.

Fig. 2D is a schematic diagram illustrating an example of the operating state of the coating drying device of the first embodiment.

Fig. 3 is a diagram showing an example of a change in the concentration of an organic solvent by operation of the coating drying device of the first embodiment.

4A is a schematic diagram illustrating another example of the operating state of the coating drying device of the first embodiment.

Fig. 4B is a schematic diagram of another example of the operating state of the coating drying device of the first embodiment.

4C is a schematic diagram illustrating another example of the operating state of the coating drying device of the first embodiment.

4D is a schematic diagram illustrating another example of the operating state of the coating drying device of the first embodiment.

Fig. 5 is a diagram showing another example of a change in the concentration of an organic solvent by operation of the coating drying device of the first embodiment.

Fig. 6A is a schematic diagram for explaining an example of the operating state of the coating drying device of the second embodiment.

Fig. 6B is a schematic diagram illustrating an example of the operating state of the coating drying device of the second embodiment.

Fig. 6C is a schematic diagram illustrating an example of the operating state of the coating drying device of the second embodiment.

Fig. 6D is a schematic diagram illustrating an example of the operating state of the coating drying device of the second embodiment.

Fig. 7 is a diagram showing an example of a change in the concentration of an organic solvent by operation of the coating drying device of the second embodiment.

Fig. 8A is a schematic diagram illustrating an example of the operating state of the coating drying device of the third embodiment.

Fig. 8B is a schematic diagram illustrating an example of the operating state of the coating drying device of the third embodiment.

Fig. 8C is a schematic diagram illustrating an example of the operating state of the coating drying device of the third embodiment.

Fig. 8D is a schematic diagram illustrating an example of the operating state of the coating drying device of the third embodiment.

Fig. 9 is a diagram showing an example of a change in the concentration of an organic solvent by operation of the coating drying device of the third embodiment.

Fig. 10 is a diagram showing an example of the change in the concentration of the organic solvent when the conveyance is stopped in addition to the stop of coating.

Detailed description of the preferred embodiment

Hereinafter, the preferred embodiments of the coating drying device and coating drying method of the present disclosure will be described with reference to the accompanying drawings. This disclosure is not limited to the specific configuration of the following embodiments, and configurations based on the same technical idea are also included in this disclosure.

(Embodiment 1)

Fig. 1 is a schematic configuration diagram showing a coating drying device 2 of the first embodiment.

The coating drying device 2 is a device that performs drying/baking processing while continuously conveying the steel strip S while coating. As shown in Figure 1, the coating drying device 2 is equipped with: a conveying section 4, a coating section 6, an oven 8, an exhaust section 10, and a concentration The measurement unit 12, and the control unit 14.

The coating drying apparatus 2 continuously conveys the steel strip S by the conveying part 4, and coats the paint containing an organic solvent (for example, the thickness of about 50 μm) at the coating position 7 by the coating part 6. After that, the steel strip S is heated in the heating space 9 in the oven 8 located on the downstream side of the coating position 7 to thereby perform the drying/baking process of the paint applied to the steel strip S.

The invention of the present disclosure particularly measures the concentration of the organic solvent of the ambient gas in the heating space 9 by the concentration measuring unit 12 connected to the heating space 9 in the oven 8, and calculates the expected arrival situation based on the measured concentration. The "predicted concentration reached". Furthermore, when the predicted concentration reaches a predetermined threshold concentration or more, the control continues to convey the steel strip S by the conveying section 4 and stops the coating by the coating section 6.

Hereinafter, each constituent element of the coating drying device 2 will be described.

The conveying unit 4 is a mechanism that continuously conveys the steel strip S to the downstream side at a fixed speed. The conveyance part 4 shown in FIG. 1 is comprised by a plurality of rotating rollers. The steel strip S is drawn from, for example, a coil material (not shown) in which a metal strip extending in a strip shape and a thin shape extends in a loop shape during the manufacturing process of a steel sheet, and is supplied to the conveying unit 4.

The coating part 6 is a member for coating the steel strip S conveyed by the conveying part 4 with paint at the coating position 7. As the paint applied by the coating section 6, a paint containing an organic solvent such as toluene and xylene is used. As shown in FIG. 1, the coating position 7 where the coating section 6 performs coating is located on the upstream side of the oven 8.

The coating section 6 shown in Figure 1 is composed of a roller with 2 rotating rollers Consists of a coating machine. Specifically, the coating section 6 has a pickup roll 6a and an applicator roll 6b as two rotating rolls, and further has a coating storage section 6c and a moving mechanism 6d. The coating roller 6a picks up the coating material stored in the coating material storage portion 6c and contacts the rotating roller of the coating roller 6b by supplying or transferring. The coating roller 6b is a rotating roller that contacts the steel strip S in such a way that the coating material supplied by the coating roller 6a is applied to the surface of the steel strip S. The paint storage portion 6c is a member (for example, a container) for storing paint. The moving mechanism 6d is a member (for example, a hydraulic cylinder) capable of integrally driving the coating roller 6a, the coating roller 6b, and the coating storage portion 6c.

In such a configuration, by the drive control of the moving mechanism 6d, the coating state for coating the steel strip S and the standby state for retreating from the coating state can be mutually switched. In Figure 1, the painting state is shown. The coating amount of the coating on the steel strip S can be controlled by controlling the pressing force and the rotation speed for pressing the coating roller 6a and the coating roller 6b against each other. In Embodiment 1, the coating amount of the coating material to the steel strip S in operation is controlled to be constant.

The oven 8 is an oven for heating the steel strip S coated with paint and drying/baking the paint on the steel strip S. The oven 8 forms a heating space 9 on the inside that is long enough to complete the drying/baking process. By maintaining the heating space 9 in the oven 8 at a predetermined temperature, the steel strip S in the heating space 9 is heated as a whole. Since the steel strip S is conveyed at a constant speed in the heating space 9, the further it goes to the downstream side of the heating space 9, the more it enters the heating of the steel strip S.

As shown in FIG. 1, the oven 8 is installed on the downstream side of the coating position 7 of the coating section 6 in the conveying direction A of the steel strip S. Painting department 6 and oven 8 It is arranged at intervals, and the section from the coating position 7 of the coating section 6 to the entrance portion of the heating space 9 of the oven 8 becomes the idling section 16 where the coated steel strip S is transported in a non-heated state.

The exhaust part 10 is a member for exhausting the heating space 9 in the oven 8. In the example of FIG. 1, the exhaust part 10 is equipped with the duct 10a and the blower 10b. The duct 10a is a pipe directly connected to the heating space 9 and ventilates the air in the heating space 9 to the outside. The blower 10b discharges the air ventilated through the duct 10a to the outside.

The concentration measuring unit 12 is a member (for example, a concentration sensor) for measuring the organic solvent concentration of the ambient gas in the heating space 9. The concentration measuring part 12 shown in Fig. 1 is connected to the position representing the heating space 9, and can directly measure the organic solvent concentration of the ambient gas in the heating space 9. Preferably, it should be installed in the assumed heating space 9 The organic solvent concentration of the gas is the highest position.

The control unit 14 is a member for controlling the operation of the coating drying device 2. The control unit 14 is constituted by, for example, a microcomputer equipped with a memory and a processing circuit corresponding to a processor such as a CPU. The control part 14 is electrically connected to at least the conveyance part 4, the coating part 6, the exhaust part 10, and the concentration measurement part 12, and controls the operation of these components.

The operation example of the coating drying device 2 constructed in this way will be described with reference to Figs. 2A-2D.

First, the temperature is raised (a temperature rise step). Specifically, the oven 8 is operated under the control of the control unit 14, so that the heating space 9 in the oven 8 is heated to a predetermined heating temperature (for example, 300 degrees), and the heating temperature is maintained. Spend.

Next, the conveyance of the steel strip S (conveyance step) is performed. Specifically, as shown in FIG. 2A, the conveying section 4 is operated under the control of the control section 14, and the steel strip S is continuously conveyed at a constant speed toward the downstream side (the conveying direction A).

Further, painting (painting step) is performed. Specifically, as shown in FIG. 2A, the coating section 6 is operated under the control of the control section 14, and the coating material is applied to the steel strip S being conveyed at the coating position 7. As mentioned above, the coating amount of the coating material by the coating part 6 is maintained constant per unit time. Thereby, the paint can be coated on the steel strip S with a uniform thickness.

In the example shown in FIG. 2A, the state of the steel strip S coated with paint before entering the heating space 9 in the oven 8 is shown. Since the steel strip S travels in the idling section 16 from the painting position 7 to the entrance part of the heating space 9, the painting starts from the painting section 6 until the painted part of the steel strip S (shown with thick lines) ) Time lag occurs until it enters the heating space 9.

Furthermore, heating is performed (heating step). Specifically, in the heating space 9 in the oven 8 maintained at a predetermined heating temperature, the coated steel strip S is heated.

Fig. 2B shows a state where the steel strip S is further conveyed from the state shown in Fig. 2A. When the coated steel strip S is heated in the heating space 9, the organic solvent contained in the paint coated on the steel strip S will evaporate. As the steel strip S entering the heating space 9 at room temperature enters downstream, the temperature gradually rises, so the organic solvent contained in the paint on the steel strip S starts to evaporate from the most upstream side in the heating space 9 and gradually increases evaporation quantity.

Figure 2B shows the organic solvent used to represent the steel strip S The degree of evaporation is 18. The amount of evaporation is 18. As shown in Fig. 2B, the coated steel strip S enters the oven 8 to start heating and evaporating. In the conveying direction A of the steel strip S, the more downstream, the more the evaporation amount of organic solvent 18 will increase. In FIG. 2B, the evaporation amount 18 is visually indicated by a diagonal line. The height of the oblique line is the amount of evaporation at its position, and the area is the amount of evaporation as a whole.

Furthermore, the concentration of the organic solvent in the ambient gas is measured (measurement step). Specifically, the concentration measuring unit 12 is operated to measure the organic solvent concentration of the ambient gas in the heating space 9. In the first embodiment, the concentration measurement unit 12 continuously measures the concentration of the organic solvent, and transmits the measurement result to the control unit 14 at any time.

Furthermore, exhaust is performed (exhaust step). Specifically, under the control of the control unit 14, the exhaust unit 10 is operated to exhaust the heating space 9. In the first embodiment, the exhaust volume of the blower 10b of the exhaust unit 10 is set to be constant per unit time.

Fig. 2C shows a state where the steel strip S is further conveyed from the state shown in Fig. 2B. As shown by the evaporation amount 20 of the organic solvent in FIG. 2C, at the evaporation end point 22, the evaporation of the organic solvent has been completed. The residual paint remaining after the organic solvent evaporates is further heated in the heating space 9, thereby being baked on the surface of the steel strip S.

Fig. 2D shows a state where the steel strip S is further conveyed from the state shown in Fig. 2C. As shown by the evaporation amount 24 of the organic solvent in FIG. 2D, the area from the entrance of the heating space 9 to the evaporation end point 22 becomes the drying area 23 where the organic solvent is evaporated and dried. The area from the end of evaporation 22 to the exit of the heating space 9 becomes the baking that the paint on the steel strip S is heated after being baked Area 25.

As mentioned above, the conveying speed of the conveying section 4, the coating volume of the coating section 6, and the exhaust volume of the exhaust section 10 are controlled to be fixed, so the evaporation volume 24 of the organic solvent in the coating in the oven 8 is constant. Maintain the state shown in Figure 2D.

Wherein, as shown in FIG. 2B, after the steel strip S enters the oven 8, the organic solvent continues to evaporate, and the evaporated organic solvent begins to diffuse in the oven 8. Therefore, the value of the measurement value measured by the concentration measurement unit 12 changes from 0.

Fig. 3 shows an example of the concentration change of the organic solvent in the ambient gas in the heating space 9 of the operation example of Figs. 2A-2D. The examples shown in FIGS. 2A-2D and FIG. 3 show that the coating amount of the coating part 6 is controlled to be normal.

FIG. 3 shows the time on the horizontal axis and the concentration of the organic solvent in the ambient gas of the heating space 9 on the vertical axis. As shown in Fig. 3, the actual average concentration of the organic solvent in the ambient gas of the heating space 9 is the actual average concentration D1, and the measured concentration D2 of the organic solvent concentration measured by the concentration measuring section 12 in the operation of the coating drying device 2 After the start (time t0), it gradually starts to increase. As shown in Figure 3, the increase in the actual average concentration D1 is delayed and the measured concentration D2 is increased. This is because the organic solvent on the steel strip S has to move until it reaches the concentration measuring part 12 after evaporating. Furthermore, the actual average concentration D1 in the first embodiment is based on the amount of organic solvent applied to the steel strip S with the coating section 6, the distance from the coating section 6 to the oven 8 (idling section 16), and the oven The capacity of 8, the exhaust volume of the exhaust section 10 from the oven 8, the speed of the steel strip S, etc. are calculated from the volatilization of the organic solvent in the oven 8 value.

After that, the actual average concentration D1 and the measured concentration D2 are both fixed and become a constant state.

In the first embodiment, the control unit 14 calculates the predicted concentration D3 based on the measured concentration D2 of the organic solvent measured by the concentration measurement unit 12. More specifically, based on the value when the measured concentration D2 of the organic solvent measured by the concentration measurement section 12 changes from 0 (time t1), the control section 14 calculates the predicted concentration D3 to be reached. After that, the calculation to reach the predicted concentration D3 is also continued.

In addition, the "value at the start of change" is not limited to the value when the concentration measurement unit 12 changes from zero during one pulse (for example, 100 ms) of the measurement period. It may also be a value obtained after time based on past data or calculation results (for example, 0.5 seconds after the organic solvent flows into the oven 8) to establish the safety countermeasure.

An example of a specific calculation formula for reaching the predicted concentration D3 is as follows. The following calculation formula is one example. If there are other mathematical formulas that can be calculated to reach the predicted concentration D3 based on the measured concentration D2 of the organic solvent, any calculation method may be used.

<Numeral 1>D3=D2/(1-exp(-(t1-x)/T))

Among them, t1 is the elapsed time from the start of painting, x is a variable including the delay time until the organic solvent flows in, and T is the time constant.

In the example shown in FIG. 3, at time t1, the control unit 14 operates The calculated arrival predicted concentration D3 does not exceed the predetermined threshold concentration D4. In this way, if the predicted concentration D3 does not exceed the predetermined threshold concentration D4, the control unit 14 determines that it is a normal state and does not perform special control. Furthermore, the critical value concentration D4 is set to a value smaller than the concentration of the lower explosive limit of the organic solvent.

Figures 2A-2D and Figure 3 show that the coating amount control of the coating section 6 is normal, but it is assumed to be due to human error during the operation of the coating drying device 2 or control of the coating amount of the coating section 6 A malfunction of the device, etc., the coating amount has been erroneous from the start of the operation (time t0), resulting in a large excess.

In order to prevent such a situation, in the coating drying device 2 of the first embodiment, control based on the measured concentration D2 of the organic solvent is performed. Specifically, the predicted concentration D3 is calculated based on the measured concentration D2 measured by the concentration measurement unit 12. When the predicted concentration D3 is above the predetermined threshold concentration D4, before the actual average concentration D1 exceeds the threshold, then Control is performed to stop the operation (painting) of the painting section 6. In the first embodiment, although the operation of the coating section 6 is stopped, the conveying section 4 continues to convey the steel strip S, and the conveying speed of the conveying section 4 and the exhaust gas volume of the exhaust section 10 are not changed and maintained at the same Speed and same displacement.

An example of the above control is shown in Figures 4A-4D and Figure 5.

As shown in FIGS. 4A and 4B, since the coating amount of the coating part 6 is incorrect and too high, the evaporation amounts 26 and 27 will be significantly increased than the evaporation amounts 18 and 20 shown in FIGS. 2B and 2C.

As shown in Figure 4A, since the steel strip S enters the oven 8 At the time when the space 9 is heated, the organic solvent evaporates, and the measurement result of the concentration measurement unit 12 starts to change. In the first embodiment, the predicted concentration D3 is calculated based on the value when the measurement concentration D2 of the organic solvent measured by the concentration measurement unit 12 first changes from 0. Specifically, according to the calculation formula shown in Equation 1, the predicted concentration D3 is calculated.

As shown in FIG. 5, at time t1, the predicted arrival density D3 calculated by the control unit 14 exceeds the predetermined threshold density D4. In this way, when the predicted concentration D3 exceeds the predetermined threshold concentration D4, the control unit 14 controls to continue the operation of the conveying unit 4 and stop the operation of the coating unit 6. Specifically, as shown in FIG. 4A, if the painting section 6 is retreated from the painting state to the standby state, the painting by the painting section 6 is stopped. At the painting end point 29, the painting on the steel strip S has ended, but the conveyance of the steel strip S continues.

FIG. 4C shows a state in which the conveyance of the steel strip S by the conveying section 4 continues in a state where the painting by the painting section 6 has stopped. As shown in FIG. 4C, from the coating end point 29 at the time when the coating portion 6 was last coated, no organic solvent evaporation occurred on the upstream side. At this time, the evaporation amount 28 of the organic solvent in the entire heating space 9 is reduced compared to the evaporation amount 27 shown in FIG. 4B (the state at the moment when the coating end point 29 enters the heating space 9 of the oven 8). In this way, the increase in the concentration of the organic solvent in the heating space 9 is suppressed.

According to such control, as shown in FIG. 5, after time t1, the maximum value P of the actual average concentration D1 can also not exceed the predetermined threshold concentration D4, and the risk of explosion can be eliminated.

Figure 4D shows the progress of the steel strip S from the state shown in Figure 4C The state of the step being transported. As shown in FIG. 4D, the steel strip S after the drying/baking process is discharged to the outside of the oven 8. The steel strip S is abnormally operating because the coating amount of the coating section 6 is set incorrectly, and therefore can be discarded later.

Then, after removing the cause of the abnormal operation, restart the operation in a normal state.

As described above, the coating drying device 2 of the first embodiment is a coating drying device 2 that continuously conveys the steel strip S while coating and drying. The coating drying device 2 is provided with: a conveying section 4 for conveying the steel strip S; a coating section 6 for coating the conveying steel strip S with a coating containing an organic solvent at the coating position 7; on the downstream side of the coating position 7 Heating space 9 Oven 8 for drying the steel strip S; Exhaust part 10 for exhausting the heating space 9 of the oven 8; Concentration measuring part for measuring the organic solvent concentration of the ambient gas in the heating space 9 of the oven 8 12; and the control unit 14 that controls the operation of the coating drying device 2. Furthermore, the control section 14 calculates the predicted concentration D3 based on the measured concentration D2 of the organic solvent measured by the concentration measurement section 12, and when the predicted concentration D3 reaches a predetermined threshold concentration D4 or more, controls the transport section 4 The conveyance continues, and the painting of the painting section 6 is stopped.

Similarly, the coating drying method of this embodiment 1 is a coating drying method in which the steel strip S is continuously conveyed on one side, and the other side is coated and dried. It includes: the step of conveying the steel strip S; The conveying steel strip S is coated with a coating containing organic solvents; a drying step in which the steel strip S is dried in the heating space 9 on the downstream side than the coating position 7; exhaust to exhaust the heating space 9 Step; Measuring step of measuring the organic solvent concentration of the ambient gas in the heating space 9; According to the measured The measured concentration D2 of the organic solvent calculates the calculation step to reach the predicted concentration D3; and when the predicted concentration D3 reaches the predetermined threshold concentration D4 or more, the coating stop step of stopping the coating while continuing the conveyance of the steel strip S.

According to the above configuration, when the calculated arrival predicted concentration D3 is equal to or greater than the predetermined threshold concentration D4, the operation of the coating section 6 is stopped, thereby suppressing the increase in the concentration of the organic solvent in the heating space 9 thereafter. Through such control, it is possible to perform control to prevent the concentration of the organic solvent in the heating space 9 from becoming too high, and to accurately prevent the organic solvent from burning due to the heat of the heating space 9, and improve safety. Furthermore, energy saving during operation can be realized.

Since the above-mentioned method and device can achieve the appropriateness of the exhaust gas volume of the exhaust portion 10, the sensible heat of the exhaust gas is suppressed to a low level, and the thermal efficiency is also improved.

In addition, according to the coating drying device 2 of the first embodiment, the control unit 14 calculates the value when the measured concentration D2 of the organic solvent measured by the concentration measuring unit 12 first changes from 0 after the coating of the coating unit 6 starts. The predicted concentration D3 is reached. Similarly, according to the coating drying method of the first embodiment, the calculation step is to calculate the predicted concentration D3 based on the value when the measured concentration D2 of the organic solvent initially changes from 0 after the start of coating.

According to the above configuration, when the calculation reaches the predicted concentration D3, by using the value when the measured concentration D2 starts to change, it is possible to quickly determine that the coating of the coating section 6 has stopped. Thereby, the increase in the concentration of the organic solvent in the heating space 9 can be quickly suppressed, and the safety can be further improved.

Furthermore, according to the coating drying device 2 of the first embodiment, When the control unit 14 reaches the predicted concentration D3 to be equal to or higher than the predetermined threshold concentration D4, the control unit 14 stops the coating by the coating unit 6 while maintaining the exhaust gas volume of the exhaust unit 10 at the same amount. Similarly, according to the coating drying method of the first embodiment, the coating stop step is to stop coating when the predicted concentration D3 reaches the predetermined threshold concentration D4 or more, while maintaining the same amount of exhaust gas.

According to the above-mentioned structure, compared with the case where the exhaust gas volume is increased when the concentration of the organic solvent in the ambient gas becomes higher, simple mechanism and control can be implemented.

(Embodiment 2)

The coating drying device 30 of the second embodiment of the present disclosure will be described. In the second embodiment, the differences from the first embodiment will be mainly explained. In the second embodiment, the same or equivalent structures as those in the first embodiment are denoted by the same reference numerals. In addition, in the second embodiment, descriptions that overlap with those in the first embodiment are omitted.

In the first embodiment, when the predicted concentration D3 is higher than the predetermined threshold concentration D4, the control to stop the coating by the coating section 6 is performed. However, in the second embodiment, the difference is in addition to stopping the coating , The control to slow down the conveying speed of the conveying section 4 is also performed together.

6A-6D and FIG. 7 respectively show an example of the operation of the coating drying device 30 of the second embodiment and an example of the concentration change of the organic solvent.

As shown in FIG. 6A, similarly to the first embodiment, the coating section 6 is retracted from the coating state to the standby state, and the coating by the coating section 6 is stopped. This is because, as shown in FIG. 7, at time t1, the predicted arrival concentration D3 calculated based on the measured concentration D2 of the concentration measuring unit 12 has exceeded the predetermined temporary concentration. The cutoff concentration is D4. In the second embodiment, the control unit 14 further controls to slow down the conveying speed of the conveying unit 4 (for example, the speed is set to 40 to 80%). Specifically, as shown in FIG. 6A, the rotation speed of the motor 31 which drives the conveyance part 4 is reduced.

Fig. 6B shows a state where the steel strip S is further conveyed from the state of Fig. 6A. In the state shown in FIG. 6B, from the entrance of the heating space 9 to the evaporation end point 32 on the downstream side, the evaporation of the organic solvent ends. Compared with the evaporation end point 22 of Embodiment 1 shown in FIG. 4B, the evaporation end point 32 of Embodiment 2 shown in FIG. 6B is located on the upstream side. This is because by slowing down the conveying speed of the conveying unit 4, the steel strip S is heated in the same time even in a smaller conveying distance.

In this way, in addition to stopping the coating of the coating section 6, the conveying speed of the conveying section 4 is also slowed down, thereby reducing the amount of paint fed into the heating space 9 per unit time. As a result, compared to the case where the conveying speed of the conveying section 4 is maintained at the same speed, the evaporation amounts 34 and 36 of the organic solvent in the heating space 9 (FIG. 6C) are reduced, and the increase in the concentration of the organic solvent can be further suppressed. . As shown in FIG. 7, it is possible to further suppress the increase in the actual average concentration D1 of the organic solvent in the heating space 9 after the coating by the coating section 6 is stopped (time t1). The maximum value P of the actual average concentration D1 is also lower than that of Embodiment 1 (Figure 5).

As described above, according to the coating drying device 30 of the second embodiment, the control section 14 not only stops the coating performed by the coating section 6, but also controls the conveying speed of the conveying section 4 to slow down. Similarly, according to the coating drying method of the second embodiment, in addition to stopping the coating, the coating stop step also slows down the conveying speed of the steel strip S.

According to such control, by slowing down the conveying speed of the steel strip S, the amount of paint entering the heating space 9 per unit time can be reduced, and therefore, the increase in the concentration of the organic solvent in the heating space 9 can be further suppressed. In this way, the safety can be further improved.

Furthermore, although the conveying speed is slowed down, if the conveying is stopped, even the most upstream part of the steel strip S in the heating space 9 will rise to the heating temperature of the oven 8 (for example, 300°C), and the organic solvent will Since the entire paint stopped in the heating space 9 evaporates at once, there is a possibility that the actual average concentration D1 exceeds the threshold concentration D4 (refer to the evaporation amount 47 shown in FIG. 10). Therefore, if the conveying speed is slowed down, it is effective to set a speed not close to that state.

(Embodiment 3)

The coating drying device 40 of the third embodiment of the present disclosure will be described. In the third embodiment, differences from the first embodiment are mainly explained. In the third embodiment, the same or equivalent configurations as in the first embodiment are given the same reference numerals and described. In addition, in the third embodiment, descriptions that overlap with those in the first embodiment are omitted.

In the first embodiment, when the predicted concentration D3 reaches the predetermined threshold concentration D4 or more, the control is performed only to stop the coating, but in the third embodiment, the difference is that in addition to the stop of the coating, there is also the drying/ Remove the applied paint before baking.

8A-8D and FIG. 9 show an example of the operation of the coating drying device 40 of the third embodiment and an example of the concentration change of the organic solvent.

As shown in Figures 8A-8D, the coating drying in Embodiment 3 The device 40 includes a removing unit 42. The removal part 42 is a member that removes the coating material of the coated steel strip S at the coating position 7 on the upstream side of the heating space 9 of the oven 8. The removal part 42 shown in FIGS. 8A-8D is a device that has a plate that can be raised and lowered up and down. The front end of the plate is pressed against the surface of the steel strip S to scrape the paint on the steel strip S. The lifting of the plate of the removing part 42 is controlled by the control part 14. In addition, a receiving pan 43 is provided under the plate, and the paint scraped off by the plate flows down to the receiving pan 43 below.

As shown in FIG. 9, at time t1, the predicted arrival concentration D3 calculated from the measured concentration D2 has exceeded the predetermined threshold concentration D4. Therefore, as shown in FIG. 8A, the coating section 6 is retreated from the coating state to the standby State, the painting by the painting section 6 is stopped.

In the third embodiment, in addition to stopping the coating performed by the coating section 6, the removal section 42 also performs paint removal. Specifically, as shown in FIG. 8A, the plate of the removal part 42 is lowered to contact the surface of the steel strip S, thereby scraping the paint with the front end of the plate. Thereby, the steel strip S in the state where no paint is applied is conveyed to the heating space 9 of the oven 8.

Fig. 8B shows a state where the steel strip S is further conveyed from the state shown in Fig. 8A. In the state shown in FIG. 8B, the evaporation of the organic solvent has ended at the evaporation end point 44. Compared with the evaporation end point 22 of Embodiment 1 shown in FIG. 4B, the evaporation end point 44 of Embodiment 3 shown in FIG. 8B is located at the same point. This is because the third embodiment also maintains the same speed as in the first embodiment without changing the conveying speed of the conveying unit 4.

On the other hand, since the removing part 42 removes the paint, as shown in FIG. 8B, the steel strip S in the heating space 9 The part is not coated with paint, and no organic solvent is evaporated. Compared with the painting end point 29 shown in FIG. 4B, the painting end point 48 shown in FIG. 8B is moved to the downstream side of the same steel strip S. Moreover, the evaporation amount 46 of the organic solvent shown in FIG. 8B is greatly reduced compared to the evaporation amount 27 of the organic solvent shown in FIG. 4B. Thereafter, as shown in FIG. 8C, the plate of the removing portion 42 is raised to return to the original position, and as shown in FIG. 8D, the coated portion is discharged.

In this way, in addition to stopping the coating by the coating section 6, the removal of the coating by the removing section 42 can reduce the amount of coating that enters the heating space 9 per unit time (in the third embodiment, it is set to 0). Thereby, the evaporation amount 46 of the organic solvent in the heating space 9 is reduced, and the increase in the concentration of the organic solvent can be suppressed. As shown in Fig. 9, after the coating by the coating section 6 stops (time t1), the increase in the actual average concentration D1 of the organic solvent in the heating space 9 is further suppressed, and the maximum value P of the actual average concentration D1 is also Even lower. In this way, safer control can be performed.

As described above, the coating drying device 40 of the third embodiment is further provided with the removing part 42 which removes the paint applied to the steel strip by the coating part 6 on the upstream side of the heating space 9 of the oven 8. Furthermore, the control unit 14 controls the removal unit 42 to remove the paint in addition to stopping the coating by the coating unit 6 when the predicted concentration D3 is equal to or higher than the predetermined threshold concentration D4. Similarly, according to the coating drying method of the third embodiment, in addition to stopping the coating, the coating stopping step also includes a step of removing the coating applied to the steel strip S at the coating position 7 on the upstream side of the heating space 9.

According to the above configuration, the paint applied to the steel strip S (the paint in the idling section 16) is removed on the upstream side of the heating space 9 of the oven 8. It can reduce the amount of paint entering the heating space 9 per unit time. Thereby, the increase in the concentration of the organic solvent in the heating space 9 can be further suppressed, and the safety can be further improved.

In the above, the above-mentioned embodiment 1-3 is used to describe the invention of the present disclosure, but the invention of the present disclosure is not limited to the above-mentioned embodiment 1-3. For example, in the above-mentioned Embodiment 1-3, the case where the conveyance part 4 is comprised by a plurality of rotating rollers was demonstrated, but it is not limited to such a form, If the steel strip S can be conveyed continuously, arbitrary structures may be adopted. In addition, in the above-mentioned embodiment 1-3, the case where the coating section 6 is constituted by a roll coater is described, but it is not limited to such a form, and if the coating material can be applied to the steel strip S, any configuration may be adopted ( For example, slit nozzle). In addition, in the above-mentioned embodiment 1-3, although the case where the exhaust part 10 is provided with the duct 10a and the blower 10b is described, it is not limited to this case, as long as the heating space 9 in the oven 8 can be exhausted. , Any configuration can also be adopted.

In addition, in the above-mentioned embodiment 1-3, the coating drying device 2 is described as a device for drying and baking the steel strip S, but it is not limited to such a form, and the baking treatment is not performed but only Drying coating drying equipment is also applicable.

In addition, in the above-mentioned embodiment 1-3, the form in which the concentration measuring section 12 is directly connected to the heating space 9 is described, but it is not limited to such a form. For example, it may be in the exhaust duct 10a of the exhaust section 10. Set the concentration measurement part on the way. Even in such a form, the organic solvent concentration of the ambient gas in the heating space 9 can be measured. In this way, the organic solvent concentration of the ambient gas in the heating space 9 can also be measured indirectly.

In the third embodiment described above, although the removal part 42 has a lifting plate and is attached to the entrance of the oven 8 is described, it is not limited to such a form. If it is possible to remove the paint on the upstream side of the heating space 9 of the oven 8, for example, a removal unit having any configuration such as a mechanism for sucking the undried and liquid paint may be used.

In addition, in the above-mentioned embodiment 1-3, although the measured concentration D2 of the organic solvent measured by the concentration measuring section 12 initially changes from 0 after the coating section 6 starts coating, the predicted concentration is calculated The form of D3 is explained, but it is not limited to such a form. For example, the organic solvent concentration may be continuously measured, and the predicted concentration D3 may be calculated based on the measured value at any point in time.

Furthermore, in the above-mentioned Embodiments 2 and 3, in order to reduce the amount of paint that enters the heating space 9 per unit time, control has been performed to slow down the conveying speed of the conveying section 4 (Embodiment 2), or by the removal section 42 The control mode (embodiment 3) of removing the paint on the steel strip S will be described, but it is not limited to such a mode. As long as it is a control that can reduce the amount of paint that enters the heating space 9 per unit time, other controls may be performed.

Furthermore, by appropriately combining any of the above-mentioned various embodiments, the respective effects can be exerted.

The present disclosure fully describes preferred embodiments with reference to the accompanying drawings, but those skilled in the art understand that various modifications or corrections can be made. It should be understood that such deformations or corrections are included in the scope of this disclosure as long as they do not exceed the scope of the attached patent application. In addition, the combination or sequence change of the elements in each embodiment can be implemented without departing from the scope and ideas of this disclosure. now.

The present disclosure is applicable as long as it is a coating drying device and a coating drying method that can carry out drying/baking processing while continuously conveying the steel strip while coating.

2: Coating drying device

4: Transport Department

6: Painting Department

6a: With paint roller

6b: Coating roller

6c: Paint storage part

6d: mobile mechanism

7: Painting position

8: Oven

9: Heating space

10: Exhaust section

10a: Catheter

10b: Blower

12: Concentration measurement department

14: Control Department

16: Idling section

28: Evaporation

29: End of painting

A: Transport direction

S: Steel belt

Claims (10)

A coating drying device is a coating drying device that continuously conveys the steel strip on one side, and coats and dries the other side. It includes: a conveying part for conveying the aforementioned steel strip; The aforementioned steel strip is coated with a coating containing an organic solvent; an oven is formed to form a heating space for drying the aforementioned steel strip on the downstream side than the aforementioned coating position; and an exhaust part is used to remove the aforementioned heating space Exhaust; a concentration measuring unit for measuring the organic solvent concentration of the organic solvent in the heating space; and a control unit for controlling the operation of the coating drying device, the control unit being based on the aforementioned concentration measured by the aforementioned concentration measuring unit The organic solvent concentration is calculated to reach the predicted concentration, and when the predicted reached concentration is above a predetermined threshold concentration, the following control is performed: continuing the conveying by the conveying section and stopping the painting by the coating section. Such as the coating drying device of claim 1, wherein the control section not only stops the coating performed by the coating section when the predicted arrival concentration is above the threshold concentration, but also performs control to slow down the transport section Transport speed. Such as the coating drying device of claim 1 or 2, which is further provided with a removal part which removes the paint applied to the steel strip by the coating part on the upstream side of the heating space, and the control part At the aforementioned arrival predicted concentration is the aforementioned threshold concentration In the above, in addition to stopping the painting by the painting part, control is also performed to remove the paint by the removing part. For example, the coating drying device of claim 1 or 2, wherein the control section performs the following control when the predicted arrival concentration is higher than the threshold concentration or higher: while maintaining the exhaust gas volume of the exhaust section at the same amount, Stop painting in the aforementioned painting department. Such as the coating drying device of claim 1 or 2, which is further provided with a removal part which removes the paint applied to the steel strip by the coating part on the upstream side of the heating space, and the control part When the predicted reaching concentration is higher than the threshold concentration, in addition to stopping the coating performed by the coating section, control is also performed to remove the coating by the removing section, and the exhaust volume of the exhaust section is simultaneously controlled. While maintaining the same amount, stop painting in the aforementioned painting section. A coating drying method is a coating drying method in which the steel strip is continuously conveyed and coated and dried on the other side. The coating drying method includes: a conveying step, conveying the aforementioned steel strip; The belt is coated with a paint containing an organic solvent; the drying step is to dry the aforementioned steel strip in the heating space on the downstream side than the aforementioned coating position; the exhaust step is to exhaust the aforementioned heating space; the measurement step is to measure the aforementioned heating space The concentration of the aforementioned organic solvent in the organic solvent; the calculation step, according to the measured concentration of the aforementioned organic solvent, calculate to Reaching the predicted concentration; and the coating stop step, when the predicted reaching concentration is above the predetermined threshold concentration, the coating is stopped while continuing the conveyance of the steel strip. The coating drying method of claim 6, wherein the step of stopping the coating includes a step of slowing down the conveying speed of the steel strip in addition to stopping the coating when the predicted concentration is above the threshold concentration. Such as the coating drying method of claim 6 or 7, wherein in the step of stopping the coating when the predicted concentration is above the threshold concentration, in addition to stopping the coating, the method further includes the following step: on the upstream side of the heating space , Remove the paint applied to the steel strip at the painting position. Such as the coating drying method of claim 6 or 7, wherein the coating stopping step is to stop the coating while maintaining the exhaust gas volume at the same amount when the predicted reaching concentration is above the threshold concentration. For example, the coating drying method of claim 6 or 7, wherein the step of stopping the coating when the predicted concentration is above the threshold concentration, in addition to stopping the coating, further includes the following step: on the upstream side of the heating space, The paint applied to the steel strip is removed at the painting position, and the painting is stopped while maintaining the exhaust gas volume at the same amount.

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