KR20190095303A - Painting Drying Device and Painting Drying Method - Google Patents

Abstract

The coating and drying apparatus for coating and drying the steel strip while continuously conveying is provided with a conveying unit, a coating unit, an oven, an exhaust unit, a concentration measuring unit, and a control unit, and the control unit is an organic solvent measured by the concentration measuring unit. The arrival prediction concentration is calculated based on the concentration, and when the arrival prediction concentration is higher than or equal to the predetermined threshold concentration, control is performed to stop the painting by the coating unit while continuing the conveyance by the conveying unit.

Description

Painting Drying Device and Painting Drying Method

The present disclosure relates to a coating drying apparatus and a coating drying method for coating and drying treatment while continuously conveying a steel strip.

DESCRIPTION OF RELATED ART Conventionally, the apparatus which coats a steel strip (a metal strip) with a roll coater (ro11 coater), The coating drying apparatus which processes the coating applied to the steel strip by drying and baking in oven, conveying a steel strip, and its method. This is proposed (for example, refer patent document 1-3).

In the coating drying apparatus of patent documents 1-3, the inside of an oven always exhausts a fixed amount with a blower, the steel strip which entered the oven rises in temperature as it enters, and the applied coating dries. In the middle of the oven, the entire amount of paint dries and enters the baking process.

Japanese Patent Application Laid-Open No. 4-193371 Japanese Patent Application Laid-Open No. 2005-262132 Japanese Patent Application Laid-Open No. 8-38855

However, in the paint drying apparatus as disclosed in Patent Literatures 1 and 2, the paint applied to the steel strip usually contains a flammable organic solvent, and the evaporated organic solvent is diffused into the atmosphere in the oven. In order to prevent the components of the organic solvent from being ignited by the heat in the oven, it is preferable to keep the concentration of the organic solvent in the atmosphere in the oven at a predetermined concentration or less, and by accurately realizing such control, the safety is improved and the exhaust gas is optimized. The development of the technology that can realize the energy saving according to this is required.

By the way, in actual operation, the coating amount may be increased by about twice or more by mistake at the start of the operation due to an artificial mistake in operating the coating drying apparatus or a failure of the control device that controls the coating amount. have. In such a case, there is a risk of causing an explosion without failing to exhaust the atmosphere having a high organic solvent concentration.

On the other hand, although the exhaust volume is increased based on the organic solvent concentration in oven like patent document 3, in order to quickly exhaust the atmosphere which became excessive organic solvent concentration, a large blower is needed, manufacturing cost rises, and large installation is carried out. Space is also needed.

Disclosure of Invention The present invention solves the above problems, and aims to improve safety in the coating drying apparatus and the coating drying method and to realize energy saving during operation.

The coating drying apparatus of one aspect of the present disclosure is a coating drying apparatus for coating and drying a steel strip while continuously conveying the steel strip, including a conveying unit for conveying the steel strip and an organic solvent in the conveyed steel strip. A coating portion for coating and painting the paint at the coating position, an oven for forming a heating space for drying the steel strip downstream from the coating position, an exhaust portion for exhausting the heating space, and the heating space. A concentration measuring unit for measuring the organic solvent concentration of the organic solvent in the above, and a control unit for controlling the operation of the coating drying apparatus, the control unit is the arrival prediction based on the organic solvent concentration measured by the concentration measuring unit When the concentration is calculated and the arrival predicted concentration is equal to or greater than a predetermined threshold concentration, the conveyance by the conveying unit is continued. A paint drying apparatus for controlling to stop the paint according to the book.

According to the said structure, the control which prevents the density | concentration of the organic solvent in a heating space from becoming too high becomes possible, and it can prevent that an organic solvent ignites by the heat of a heating space, and can improve safety. .

In the above-mentioned coating drying apparatus, when the said arrival predicted density | concentration is more than the said threshold density | concentration, you may control so that the conveyance speed by the said conveyance part may be slowed with the coating stop by the said coating part. As a result, the concentration increase of the organic solvent can be further suppressed, and the safety can be further improved.

The coating drying apparatus further includes a removing unit for removing the paint applied to the steel strip by the coating unit from an upstream side of the heating space, and the control unit is configured to have the at least one estimated concentration concentration In addition to stopping the painting by the coating unit, the removal unit may control to remove the paint. As a result, the concentration increase of the organic solvent can be further suppressed, and the safety can be further improved.

In the coating drying apparatus, the control unit may control to perform the painting stop according to the coating section while maintaining the exhaust amount by the exhaust section at the same amount when the attained predicted concentration is equal to or greater than the threshold concentration. do. Thereby, it can implement as simple control and a mechanism.

The coating drying method of one aspect of the present disclosure is a coating drying method for coating and drying a steel strip while continuously conveying the steel strip, and the step of conveying the steel strip and a paint containing an organic solvent with respect to the steel strip being conveyed at a coating position. A coating step to apply, a drying step of drying the steel strip in a heating space downstream of the coating position, an exhausting step of exhausting the heating space, and an organic solvent concentration of the organic solvent in the heating space. A measurement step of measuring the temperature, a calculation step of calculating the arrival prediction concentration based on the measured organic solvent concentration, and stopping the coating while continuing the conveyance of the steel strip when the arrival prediction concentration is equal to or greater than a predetermined threshold concentration. It is a coating drying method including the painting stop step.

According to the said structure, the control which prevents the density | concentration of the organic solvent in a heating space from becoming too high becomes possible, and safety can be improved, such as reliably preventing the organic solvent from ignition by the heat of a heating space. .

In the coating drying method, the painting stop step may include a step of slowing the conveying speed of the steel strip together with stopping the painting when the attained predicted concentration is equal to or greater than the threshold concentration. As a result, the concentration increase of the organic solvent can be further suppressed, and the safety can be further improved.

In the coating drying method, in the painting stop step, when the attained predicted concentration is equal to or greater than the threshold concentration, the coating is stopped and the paint applied to the steel strip at the coating position is removed upstream from the heating space. You may include the step to make. As a result, the concentration increase of the organic solvent can be further suppressed, and the safety can be further improved.

In the coating drying method, the coating stop step may stop the painting while maintaining the exhaust amount at the same amount when the attained predicted concentration is equal to or greater than the threshold concentration. Thereby, it can implement as easy control.

According to the present disclosure, safety can be improved.

These aspects and features of the present invention will become apparent from the following description relating to the preferred embodiments of the accompanying drawings.
1 is a diagram illustrating a schematic configuration of a paint drying apparatus according to the first embodiment.
2A is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the first embodiment.
2B is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the first embodiment.
2C is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the first embodiment.
2D is a schematic diagram illustrating an example of an operating state of a paint drying apparatus according to the first embodiment.
FIG. 3 is a diagram showing an example of a concentration change of an organic solvent according to the operation of the paint drying apparatus in the first embodiment.
4A is a schematic diagram illustrating another example of the operating state of the paint drying apparatus according to the first embodiment.
4B is a schematic view for explaining another example of the operating state of the paint drying apparatus according to the first embodiment.
4C is a schematic view for explaining another example of an operating state of the paint drying apparatus according to the first embodiment.
4D is a schematic diagram illustrating another example of the operating state of the paint drying apparatus according to the first embodiment.
5 is a diagram illustrating another example of the concentration change of the organic solvent according to the operation of the paint drying apparatus according to the first embodiment.
6A is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the second embodiment.
6B is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the second embodiment.
6C is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the second embodiment.
6D is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the second embodiment.
FIG. 7 is a diagram showing an example of a concentration change of the organic solvent according to the operation of the paint drying apparatus according to the second embodiment. FIG.
8A is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the third embodiment.
8B is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the third embodiment.
8C is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the third embodiment.
8D is a schematic diagram illustrating an example of an operating state of the paint drying apparatus according to the third embodiment.
9 is a diagram showing an example of a concentration change of the organic solvent according to the operation of the paint drying apparatus according to the third embodiment.
The figure which shows an example of the density | concentration change of the organic solvent at the time of stopping conveyance with stopping of coating.

EMBODIMENT OF THE INVENTION Hereinafter, the preferred embodiment of the coating drying apparatus and coating drying method which concern on this indication is demonstrated, referring an accompanying drawing. The present disclosure is not limited to the specific configuration of the following embodiments, and the configuration based on the same technical idea is included in the present disclosure.

(Embodiment 1)

FIG. 1: is a figure which shows schematic structure of the coating drying apparatus 2 in Embodiment 1. As shown in FIG.

The coating drying apparatus 2 is an apparatus which paints while drying and conveying the steel strip S, and is drying and baking. As shown in FIG. 1, the painting drying apparatus 2 includes a conveying section 4, a coating section 6, an oven 8, an exhaust section 10, a concentration measuring section 12, The control unit 14 is provided.

The coating drying apparatus 2 applies the coating material containing the organic solvent in the coating position 7 by the coating part 6, conveying the steel strip S continuously by the conveyance part 4 (for example, thickness About 50 μm). Thereafter, the steel strip S is heated in the heating space 9 in the oven 8 on the downstream side of the coating position 7, thereby drying and baking the coating applied to the steel strip S.

The invention of the present disclosure particularly measures the concentration of the organic solvent in the atmosphere in the heating space 9 by the concentration measuring unit 12 connected to the heating space 9 in the oven 8, and based on the measured concentration, After that, the "arrival prediction concentration" is calculated as the concentration to be reached. Furthermore, when reaching | attained prediction density | concentration is more than predetermined threshold density | concentration, it controls so that the painting by the coating part 6 may be stopped, conveying the steel strip S by the conveyance part 4, and continuing.

Hereinafter, each component of the coating drying apparatus 2 is demonstrated.

The conveyance part 4 is a mechanism which continuously conveys the steel strip S to a downstream side at a fixed speed. The conveyance part 4 shown in FIG. 1 is comprised by the some rotation roll. The steel strip S is supplied to the conveyance part 4, for example, by unwinding from the coil material (not shown) which the metal strip thinly stretched to strip shape in the manufacturing process of a steel plate wound in the donut shape.

The coating part 6 is a member which apply | coats a coating material at the coating position 7 with respect to the steel strip S conveyed by the conveyance part 4. As a coating material which the coating part 6 applies, the coating material containing organic solvents, such as toluene and xylene, is used. As shown in FIG. 1, the painting position 7 along the painting portion 6 is upstream than the oven 8.

The coating part 6 shown in FIG. 1 is comprised by the roll coater which has two rotary rolls. Specifically, the coating part 6 is provided with the pick-up roll 6a and the applicator roll 6b as two rotary rolls, and is further equipped with the paint storage part 6c and the moving mechanism 6d. . The pick-up roll 6a is a rotary roll which raises the paint stored in the paint storage part 6c, and makes contact with the applicator roll 6b so that it may be supplied or transferred. The applicator roll 6b is a rotary roll which contacts the steel strip S so that the coating material supplied from the pickup roll 6a may be apply | coated to the surface of the steel strip S. FIG. The coating material storage part 6c is a member (for example, a container) which stores coating material. The moving mechanism 6d is a member (for example, a hydraulic cylinder) which can drive the pickup roll 6a, the applicator roll 6b, and the paint reservoir 6c integrally.

In such a configuration, by the drive control of the moving mechanism 6d, it is possible to switch between the coating state for coating the steel strip S and the standby state withdrawn from the painting state. In FIG. 1, the painting state is shown. The coating amount of the paint on the steel strip S can be controlled by controlling the pressing force and the rotational speed for pressing the pick-up roll 6a and the applicator roll 6b to each other. In Embodiment 1, the application amount of the coating material to the steel strip S in operation is controlled constantly.

The oven 8 is a furnace for drying and baking the coating on the steel strip S by heating the steel strip S coated with the coating material. The oven 8 forms inside the heating space 9 of a length sufficient 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 the constant speed in the heating space 9, heating of the steel strip S advances toward the downstream of the heating space 9. As shown in FIG.

As shown in FIG. 1, the oven 8 is provided downstream from the coating position 7 by the coating part 6 in the conveyance direction A of the steel strip S. As shown in FIG. The coating part 6 and the oven 8 are arrange | positioned at intervals, and the area | region from the coating position 7 of the coating part 6 to the inlet part of the heating space 9 of the oven 8 is coating. The completed steel strip S becomes the free-flow section 16 conveyed in a non-heated state.

The exhaust unit 10 is a member that exhausts 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 allows air in the heating space 9 to be vented to the outside. The blower 10b discharges the air vented through the duct 10a to the outside.

The concentration measuring part 12 is a member which measures the organic solvent density | concentration of the atmosphere in the heating space 9 (for example, concentration sensor). The concentration measuring part 12 shown in FIG. 1 is connected to the position which represents the heating space 9 so that the organic-solvent density | concentration of the atmosphere in the heating space 9 can be measured directly, Preferably, the heating space 9 It is good to be provided in the position where it is assumed that the organic solvent concentration of atmosphere is the highest in ().

The control unit 14 is a member that controls the operation of the paint drying apparatus 2. The control part 14 is comprised by the microcomputer provided with the processing circuit corresponding to a processor, such as a memory and a CPU, for example. The control part 14 is electrically connected to the conveyance part 4, the coating part 6, the exhaust part 10, and the density | concentration measuring part 12 at least, and controls the operation of these members.

The operation example of the coating drying apparatus 2 comprised in this way is demonstrated using FIG. 2A-2D.

First, temperature rising is performed (heating step). Specifically, the oven 8 is operated under the control of the controller 14, the entire heating space 9 in the oven 8 is heated up to a predetermined heating temperature (for example, 300 degrees), and the heating temperature. Keep it.

Next, the steel strip S is conveyed (conveying step). Specifically, as shown in FIG. 2A, the conveying unit 4 is driven under the control of the control unit 14 to continuously convey the steel strip S at a constant speed toward the downstream side (conveying direction A). .

Furthermore, coating is performed (painting step). Specifically, as shown to FIG. 2A, the coating part 6 is operated under the control of the control part 14, and the coating material is apply | coated in the coating position 7 with respect to the steel strip S conveyed. As mentioned above, the coating amount of the coating material by the coating part 6 is kept constant per unit time. As a result, the coating material is applied to the steel strip S in a uniform thickness.

In the example shown in FIG. 2A, the state just before entering the heating space 9 in the oven 8 by the coating steel strip S is shown. Since the steel strip S travels the princess section 16 from the painting position 7 to the inlet part of the heating space 9, after starting painting by the coating part 6, A time lag occurs until the painted part (shown in bold line) enters the heating space 9.

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

FIG. 2B shows a state in which 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 coating material apply | coated to the steel strip S evaporates. Since the steel strip S which entered the heating space 9 at normal temperature advances downstream, the temperature gradually rises, so that the organic solvent contained in the paint on the steel strip S is the most upstream in the heating space 9. Evaporation starts from the side, and evaporation amount gradually increases.

In FIG. 2B, the evaporation amount 18 which shows the evaporation degree of the organic solvent in the steel strip S is shown. As shown in Fig. 2B, heating and evaporation proceed after the coated steel strip S enters the oven 8, and the amount of evaporation of the organic solvent 18 toward the downstream side in the conveying direction A of the steel strip S (18). ) Is rising. In FIG. 2B, the evaporation amount 18 is shown visually in an oblique part. The height of the diagonal portion is the amount of evaporation at the position, and the area is the amount of evaporation of the whole.

In addition, the concentration of the organic solvent in the atmosphere is measured (measurement step). Specifically, the concentration measuring unit 12 is driven to measure the organic solvent concentration in the atmosphere in the heating space 9. In the first embodiment, the concentration measurement of the organic solvent by the concentration measuring unit 12 is continuously performed, and the measurement result is frequently transmitted to the control unit 14.

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

FIG. 2C shows a state in which the steel strip S is further conveyed from the state shown in FIG. 2B. As shown in the evaporation amount 20 of the organic solvent in FIG. 2C, evaporation of the organic solvent is completed in the evaporation end point 22. As shown in FIG. The remaining paint after evaporation of the organic solvent is further heated in the heating space 9 to be baked on the surface of the steel strip S.

FIG. 2D shows a state in which the steel strip S is further conveyed from the state shown in FIG. 2C. As shown in the evaporation amount 24 of the organic solvent in FIG. 2D, the area | region from the inlet of the heating space 9 to the evaporation end point 22 becomes the drying area | region 23 in which the organic solvent evaporates and dries. The region from the evaporation end point 22 to the exit of the heating space 9 becomes the baking region 25 in which the paint on the steel strip S is heated and baked.

As mentioned above, since the conveyance speed by the conveyance part 4, the coating amount by the coating part 6, and the exhaust amount by the exhaust part 10 are controlled uniformly, the organic solvent in the coating material in the oven 8 The evaporation amount 24 is normalized and the state shown in FIG. 2D is maintained.

Here, as shown in FIG. 2B, after the steel strip S enters the oven 8, evaporation of the organic solvent proceeds, and the evaporated organic solvent begins to diffuse in the oven 8. Thereby, the value of the measured value by the density | concentration measuring part 12 starts to change from zero.

An example of the transition of the concentration of the organic solvent of the atmosphere in the heating space 9 by the operation example of FIGS. 2A-2D is shown in FIG. 2A-2D and the example shown in FIG. 3 show the case where the coating amount by the coating part 6 is normally controlled.

3 shows the concentration of the organic solvent in the atmosphere of the heating space 9 on the horizontal axis and time on the vertical axis. As shown in FIG. 3, the actual average concentration Dl which is the actual average concentration of the organic solvent in the atmosphere of the heating space 9, and the measured concentration D2 which is the organic solvent concentration which the density measurement part 12 measured. Then, after the start of operation (time tO) of the coating drying apparatus 2, it gradually starts to increase. As shown in FIG. 3, the measured concentration D2 increases later than the increase in the actual average concentration D1. This is because the movement is required until the organic solvent on the steel strip S reaches the concentration measuring unit 12 after evaporation. In addition, the real average concentration Dl in this Embodiment 1 is the quantity of the organic solvent apply | coated to the steel strip S in the coating part 6, and the distance from the coating part 6 to the oven 8 (princess Section 16), the volume of the oven 8, the amount of volatilization of the organic solvent in the oven 8, based on the amount of exhaust from the oven 8 along the exhaust 10, the speed of the steel strip S, and the like. The value calculated from

Thereafter, both the actual average concentration Dl and the measured concentration D2 become constant, and the steady state is brought to pass.

In the first embodiment, the control unit 14 calculates the arrival prediction concentration D3 based on the measurement concentration D2 of the organic solvent measured by the concentration measurement unit 12. More specifically, when the measured concentration D2 of the organic solvent measured by the concentration measuring unit 12 changes from 0 for the first time, based on the value of (time t1), the controller 14 determines the arrival predicted concentration ( Calculate D3). Even after that, calculation of arrival prediction density D3 is continued.

In addition, the "value when it changes for the first time" is not limited to the value when it changes from zero between 1 pulse (for example, 100 ms) of the measurement period of the density | concentration measuring part 12. FIG. The value after the time obtained based on the past data or the calculation result may be sufficient so that this safety measure is established (for example, 5 seconds after the organic solvent flows into the oven 8).

An example of the specific calculation formula of arrival prediction density | concentration D3 is as follows. The following calculation formula is an example, In addition, as long as it calculates arrival prediction density | concentration D3 based on the measurement density | concentration D2 of the organic solvent, you may use arbitrary calculation methods.

<Equation 1>

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

Here, t1 is elapsed time from the start of coating, x is a variable including the lag time until the inflow of the organic solvent, and T is a time constant.

In the example shown in FIG. 3, the arrival prediction concentration D3 calculated by the control unit 14 at the time t1 does not exceed a predetermined threshold concentration D4. In this way, when the arrival prediction concentration D3 does not exceed the predetermined threshold concentration D4, the control unit 14 determines that the steady state is not performed, and no special control is performed. In addition, the threshold density | concentration D4 is made into a value smaller than the density | concentration of the explosion lower limit of an organic solvent.

In FIG. 2A-2D and FIG. 3, although the application amount by the coating part 6 was shown to be normally controlled, the artificial mistake at the time of operating the coating drying apparatus 2 and the application amount of the coating part 6 are controlled. It is assumed that the application amount is excessively large from the start time of operation (time tO) due to the failure of the control device.

In preparation for such a case, in the coating drying apparatus 2 of Embodiment 1, control based on the measurement density | concentration D2 of the organic solvent is performed. Specifically, when the arrival prediction concentration D3 is calculated based on the measurement concentration D2 by the concentration measurement unit 12, and the arrival prediction concentration D3 is equal to or more than a predetermined threshold concentration D4, Control is made to stop the operation (painting) of the coating part 6 before the actual average concentration Dl exceeds the threshold. In Embodiment 1, conveyance of the steel strip S by the conveyance part 4 is continued while the operation of the coating part 6 is stopped, and at the same time, the conveyance speed and exhaust part 10 by the conveyance part 4 are carried out. The exhaust volume by) is not changed, and is maintained at the same speed and the same exhaust volume.

An example of the control is shown in FIGS. 4A-4D and FIG. 5.

As shown in Figs. 4A and 4B, since the coating amount by the coating portion 6 is too high, the evaporation amounts 26 and 27 are significantly larger than the evaporation amounts 18 and 20 shown in Figs. 2B and 2C. have.

As shown in FIG. 4A, since the organic solvent evaporates when the steel strip 3 enters the heating space 9 in the oven 8, the measurement result by the concentration measuring unit 12 starts to change. In the first embodiment, the arrival predicted concentration D3 is calculated based on the value when the measured concentration D2 of the organic solvent measured by the concentration measuring unit 12 changes from 0 for the first time. Specifically, the arrival prediction concentration D3 is calculated by the calculation formula shown in Expression (1).

As shown in FIG. 5, the arrival prediction concentration D3 calculated by the control unit 14 at the time t1 exceeds the predetermined threshold concentration D4. In this way, when the arrival prediction concentration D3 exceeds the predetermined threshold concentration D4, the control unit 14 controls to stop the operation of the coating unit 6 while continuing the operation of the transfer unit 4. . Specifically, as shown in FIG. 4A, the coating by the coating portion 6 is stopped by retracting the coating portion 6 from the painting state to the standby state. Although painting on the steel strip S is complete | finished by the coating end point 29, conveyance of the steel strip S is continued.

The state which continued conveyance of the steel strip 3 by the conveyance part 4 in the state which stopped coating by the coating part 6 is shown to FIG. 4C. As shown in FIG. 4C, evaporation of the organic solvent does not occur on the upstream side from the coating end point 29, which is the point where the painting by the coating section 6 was last performed. At this time, the evaporation amount 28 of the organic solvent in the whole heating space 9 is the evaporation amount shown in FIG. 4B (the state when the coating end point 29 entered the heating space 9 of the oven 8). It is decreasing compared with (27). Thus, the increase of the concentration of the organic solvent in the heating space 9 is suppressed.

According to such a control, as shown in FIG. 5, even after time t1, the maximum value p of the real average concentration Dl can be made to not exceed predetermined threshold concentration D4, and the danger of an explosion may be reached. Can be eliminated.

4D shows a state in which the steel strip S is further conveyed from the state shown in FIG. 4C. As shown in FIG. 4D, the steel strip S on which the drying and baking treatment is completed is discharged to the outside of the oven 8. Since this steel strip S is based on the abnormal operation in which the coating amount of the coating part 6 was set incorrectly, you may discard it after that.

After that, the cause of abnormal operation is eliminated, and operation is started again in a normal state.

As mentioned above, the coating drying apparatus 2 of this Embodiment 1 is the coating drying apparatus 2 which coats and dry-processes while conveying the steel strip S continuously. The coating drying apparatus 2 has the conveyance part 4 which conveys the steel strip S, and the coating part 6 which apply | coats the coating material containing the organic solvent with respect to the conveyed steel strip S in the coating position 7. And the oven 8 for drying the steel strip S in the heating space 9 on the downstream side from the painting position 7, and the exhaust unit 10 for exhausting the heating space 9 of the oven 8. And a concentration measuring unit 12 for measuring the concentration of the organic solvent in the atmosphere in the heating space 9 of the oven 8, and a control unit 14 for controlling the operation of the coating drying apparatus 2. In addition, the control unit 14 calculates the arrival prediction concentration D3 based on the measurement concentration D2 of the organic solvent measured by the concentration measurement unit 12, and the arrival prediction concentration D3 is a predetermined threshold concentration ( In the case of D4) or more, it controls so that painting by the coating part 6 may be stopped, conveying by the conveyance part 4 continues.

Similarly, the coating drying method of this Embodiment 1 is a coating drying method of coating and drying-processing steel strip S while carrying it continuously, It is organic with respect to the step which conveys steel strip S, and the steel strip S conveyed. A coating step of applying the paint including the solvent at the coating position 7, a drying step of drying the steel strip S in the heating space 9 on the downstream side of the coating position 7, and a heating space 9. Calculation of calculating the arrival prediction concentration D3 based on the exhaust gas exhausting step, the measuring step of measuring the concentration of the organic solvent in the atmosphere in the heating space 9, and the measured concentration D2 of the measured organic solvent. Step and the coating stop step which stops coating, continuing conveyance of the steel strip S, when the arrival prediction density | concentration D3 is more than predetermined threshold density | concentration D4.

According to the said structure, when the calculated arrival prediction density | concentration D3 is more than predetermined threshold concentration D4, operation | movement of the coating part 6 is stopped, and the density | concentration of the organic solvent in the heating space 9 after that raises. Can be suppressed. By such a control, the control which prevents the density | concentration of the organic solvent in the heating space 9 from becoming too high becomes possible, and it is possible to accurately prevent the organic solvent from ignition by heat of the heating space 9 Etc., safety can be improved. Furthermore, energy saving at the time of operation can be realized.

Since the exhaust gas sensible heat was suppressed low because it was possible to achieve an appropriate amount of the exhaust amount by the exhaust part 10 in the above method and apparatus, the thermal efficiency was improved.

Moreover, according to the coating drying apparatus 2 of this Embodiment 1, the control part 14 is the measurement density | concentration D2 of the organic solvent which the density | concentration measuring part 12 measures after the coating start by the coating part 6. Calculates the arrival prediction concentration (D3) based on the value when is first changed from 0. Similarly, according to the paint drying method of the first embodiment, the calculation step calculates the arrival prediction concentration D3 based on the value when the measured concentration D2 of the organic solvent first changes from 0 after the start of coating. do.

According to the said structure, when calculating | requiring reach | attainment prediction density | concentration D3, the coating stop by the coating part 6 can be judged quickly by using the value when the measured density | concentration D2 changes for the first time. Thereby, the concentration rise of the organic solvent in the heating space 9 can be suppressed quickly, and safety can further be improved.

Moreover, according to the coating-drying apparatus 2 of this Embodiment 1, the control part 14 equals the exhaust amount by the exhaust part 10, when the arrival prediction density | concentration D3 is more than predetermined threshold concentration D4. The painting stop by the coating part 6 is performed, maintaining as it is. Similarly, according to the painting drying method of the first embodiment, the painting stop step performs the painting stop while maintaining the exhaust amount at the same amount when the arrival predicted concentration D3 is equal to or larger than the predetermined threshold concentration D4.

According to the said structure, it can implement as a simple mechanism and control, compared with the case where exhaust volume is increased when the organic solvent concentration in atmosphere is high.

(Embodiment 2)

The coating-drying apparatus 30 of Embodiment 2 which concerns on this indication is demonstrated. In Embodiment 2, the point mainly different from Embodiment 1 is demonstrated. In Embodiment 2, the structure which is the same as or equivalent to Embodiment 1 is attached | subjected and demonstrated. In addition, in Embodiment 2, description overlapping with Embodiment 1 is abbreviate | omitted.

In Embodiment 1, when the arrival prediction concentration D3 is equal to or greater than the predetermined threshold concentration D4, control to stop the coating by the coating unit 6 is performed. In Embodiment 2, in addition to stopping the painting, The point of carrying out the control which slows a conveyance speed by the conveyance part 4 is different.

6A-6D and FIG. 7 show an example of the operation of the paint drying apparatus 30 according to the second embodiment and an example of the concentration transition of the organic solvent.

As shown in FIG. 6A, similarly to Embodiment 1, the coating part 6 is evacuated from a coating state to a standby state, and the coating by the coating part 6 is stopped. As shown in Fig. 7, the arrival predicted concentration D3 calculated based on the measured concentration D2 of the concentration measuring unit 12 at the time t1 exceeds the predetermined threshold concentration D4. Because.

In Embodiment 2, the control part 14 further controls so that the conveyance speed by the conveyance part 4 may be slowed down (for example, at 40 to 80% of speed). Specifically, as shown in FIG. 6A, the rotational speed of the motor 31 driving the conveying unit 4 is lowered.

The state where the steel strip S was further conveyed from the state of FIG. 6A is shown to FIG. 6B. In the state shown in FIG. 6B, the evaporation of the organic solvent is complete | finished in the evaporation end point 32 in the downstream side from the inlet of the heating space 9. 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 upstream. This is because, as the conveyance speed by the conveyance unit 4 is slowed down, the steel strip S is heated at the same time even with a small conveyance distance.

In this way, the amount of paint entering the heating space 9 per unit time is reduced by slowing the conveying speed by the conveying unit 4 together with the stopping of the painting by the coating unit 6. Thereby, compared with the case where it does not slow down the conveyance speed by the conveyance part 4, the evaporation amount 34 and 36 (FIG. 6C) of the organic solvent in the heating space 9 becomes small, The concentration rise of the organic solvent can be further suppressed. As shown in FIG. 7, the raise of the real average concentration D1 of the organic solvent in the heating space 9 after the coating stop (time t1) by the coating part 6 can be suppressed more. The maximum value p of the real average concentration D1 is also lower than that of the first embodiment (FIG. 5).

As mentioned above, according to the coating drying apparatus 30 of this Embodiment 2, the control part 14 controls so that the conveyance speed by the conveyance part 4 may be slowed in addition to the painting stop by the coating part 6. do. Similarly, according to the coating drying method of this Embodiment 2, a painting stop step slows the conveyance speed of the steel strip S with stopping of painting.

According to such control, since the amount of paint entering the heating space 9 per unit time can be reduced by slowing the conveyance speed of the steel strip S, further increasing the concentration of the organic solvent in the heating space 9 is further suppressed. can do. This can further improve safety.

In addition, even if the conveyance speed is slowed down, in the case where the conveyance is stopped, the heating temperature of the oven 8 is also at the most upstream side of the steel strip S in the heating space 9 (for example, 300 ° C). ), And since the organic solvent evaporates simultaneously from the whole paint stopped in the heating space 9, there exists a possibility that the actual average concentration D1 may exceed the threshold concentration D4 (the evaporation amount shown in FIG. 10 ( 47). Therefore, when slowing a conveyance speed, it is effective to set it as the speed which does not approach such a state.

(Embodiment 3)

The coating drying apparatus 40 of Embodiment 3 which concerns on this indication is demonstrated. In Embodiment 3, the point mainly different from Embodiment 1 is demonstrated. In Embodiment 3, the structure which is the same as or equivalent to Embodiment 1 is attached | subjected and demonstrated. In addition, in Embodiment 3, description overlapping with Embodiment 1 is abbreviate | omitted.

In Embodiment 1, when control | attainment prediction density | concentration D3 is more than predetermined threshold density | concentration D4, it controlled so that only coating may be performed. In Embodiment 3, in addition to stopping coating, the paint which has already been painted is dried. · The removal point before baking is different.

8A-8D and FIG. 9 show an example of the operation of the coating drying apparatus 40 according to the third embodiment and an example of the concentration transition of the organic solvent.

As shown to FIG. 8A-8D, the coating-drying apparatus 40 in Embodiment 3 is equipped with the removal part 42. FIG. The removal part 42 is a member which removes the paint apply | coated to the steel strip S in the application | coating position 7 from the upstream rather than the heating space 9 of the oven 8. The removal part 42 shown to FIGS. 8A-8D is a device which has a plate which can move up and down, and scrapes the paint on the steel strip S by pressing the tip of the plate against the surface of the steel strip S. FIG. The lifting and lowering of the plate of the removal part 42 is controlled by the control part 14. Moreover, the support tray 43 is provided in the lower part of the plate, and the paint scraped off by the plate flows to the lower support tray 43.

As shown in FIG. 9, since the arrival prediction density | concentration D3 calculated based on the measurement density | concentration D2 in time t1 exceeds the predetermined threshold density | concentration D4, as shown to FIG. 8A, coating The part 6 is retracted from the painting state to the standby state, and the painting by the painting portion 6 is stopped.

In the third embodiment, the paint is removed by the removal unit 42 together with the stopping of the painting by the coating unit 6. Specifically, as shown in FIG. 8A, the plate is removed from the distal end of the plate by lowering the plate of the removal unit 42 and contacting the surface of the steel strip S. As shown in FIG. Thereby, the steel strip S of the state in which the coating material is not apply | coated to the heating space 9 of the oven 8 is conveyed.

FIG. 8B shows a state in which 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 is complete | finished at the evaporation end point 44. FIG. 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 in the third embodiment, similarly to the first embodiment, the conveying speed by the conveying unit 4 is maintained at the same speed without changing.

On the other hand, since the coating material is removed by the removing unit 42, as shown in Fig. 8B, the coating material is not applied on the upstream side of the steel strip S in the heating space 9, No evaporation of the organic solvent occurs. The coating end point 48 shown in FIG. 8B is moved to the downstream side in the same steel strip S than the coating end point 29 shown in FIG. 4B. In addition, the evaporation amount 46 of the organic solvent shown in FIG. 8B is significantly smaller than the evaporation amount 27 of the organic solvent shown in FIG. 4B. Thereafter, as shown in FIG. 8C, the plate of the removal unit 42 is raised to return to its original position, and as shown in FIG. 8D, the coated portion is discharged.

In this manner, the coating stop by the coating section 6 and the removal of the coating by the removal section 42 can reduce the amount of paint entering the heating space 9 per unit time (in Embodiment 3). 0). Thereby, the evaporation amount 46 of the organic solvent in the heating space 9 decreases, and the density | concentration raise of the organic solvent can be suppressed. As shown in FIG. 9, the raise of the real average concentration Dl of the organic solvent in the heating space 9 after the coating stop (time tl) by the coating part 6 is further suppressed, The maximum value p of the average concentration Dl is further lowered. In this way, safer control is possible.

As mentioned above, the coating drying apparatus 40 of this Embodiment 3 has the removal part which removes the paint apply | coated to the steel strip by the coating part 6 in the upstream rather than the heating space 9 of the oven 8 ( 42). Furthermore, the control part 14 removes the paint by the removal part 42 with the coating stop by the coating part 6, when the arrival prediction density | concentration D3 is more than predetermined threshold concentration D4. To control. Similarly, according to the painting drying method of the third embodiment, the painting stop step removes the coating material applied to the steel strip S at the painting position 7 from the upstream side rather than the heating space 9 in addition to stopping the painting. It includes a step.

According to the said structure, the coating material (painting in the princess section 16) apply | coated to the steel strip S is removed to the heating space 9 per unit time by removing from the upstream side rather than the heating space 9 of the oven 8. The amount of paint coming in can be reduced. Thereby, the concentration rise of the organic solvent in the heating space 9 can be further suppressed, and safety can further be improved.

As mentioned above, although the invention of this indication was demonstrated taking the above-mentioned Embodiment 1-3 as an example, the invention of this indication is not limited to Embodiment 1-3 mentioned above. For example, in the said Embodiment 1-3, the case where the conveyance part 4 was comprised by the some rotational roll was demonstrated, It is not limited to such a case, If the steel strip S can be conveyed continuously, Any configuration may be employed. In addition, in the said Embodiment 1-3, the case where the coating part 6 was comprised by the roll coater was demonstrated, It is not limited to such a case, If a coating material can be apply | coated to the steel strip S, arbitrary structures are implemented. You may employ | adopt (for example, a slit nozzle). In addition, in the said Embodiment 1-3, the case where the exhaust part 10 was comprised including the duct 10a and the blower 10b was demonstrated, It is not limited to such a case, The heating space in the oven 8 was not limited to this. As long as it is possible to exhaust (9), any configuration may be adopted.

In addition, in the said Embodiment 1-3, the case where it was the apparatus which dry-bakes steel strip S as the coating drying apparatus 2 was demonstrated, It is not limited to such a case, without carrying out baking process Even the coating drying apparatus which performs only a drying process is applicable.

In addition, although the case where the density measurement part 12 was connected directly to the heating space 9 was demonstrated in the said Embodiment 1-3, it is not limited to such a case, For example, the exhaust part 10 You may provide a density | concentration measuring part in the middle of the exhaust duct 10a. Even in such a case, the organic solvent concentration of the atmosphere in the heating space 9 can be measured. Thus, the organic solvent concentration of the atmosphere in the heating space 9 may be indirectly measured.

In addition, in the said Embodiment 3, the case where the removal part 42 has a plate which can raise and lower is provided in the inlet of the oven 8 was demonstrated, It is not limited to such a case. If the paint can be removed from the upstream side of the heating space 9 of the oven 8, for example, a removal unit having any configuration may be employed, such as a mechanism for sucking liquid paint by dry drying.

In addition, in the said Embodiment 1-3, based on the value when the measured density | concentration D2 of the organic solvent measured by the density | concentration measuring part 12 measured after the coating start by the coating part 6 changed from 0 for the first time, Although the case where the arrival prediction density | concentration D3 was computed was demonstrated, it is not limited to such a case. For example, while measuring the organic solvent concentration continuously, you may calculate arrival prediction density | concentration D3 based on the measurement value of arbitrary timing.

In addition, in the second and third embodiments, in order to reduce the amount of paint entering the heating space 9 per unit time, the control for slowing the conveying speed by the conveying section 4 (second embodiment) or the removing section 42 When the control which removes the paint on the steel strip S by () was performed (Embodiment 3), it is not limited to such a case. As long as the control can reduce the amount of paint entering the heating space 9 per unit time, other control may be executed.

In addition, by combining appropriately any of the above-described embodiments, it is possible to exhibit the effects each has.

The present disclosure has been sufficiently described with reference to the accompanying drawings, with reference to the preferred embodiments, but various modifications and changes are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present disclosure as defined by the appended claims. In addition, the change of the combination and order of elements in each embodiment can be implemented without deviating from the range and idea of this indication.

The present disclosure is applicable as long as it is a coating drying apparatus and a coating drying method for coating, drying and baking the steel strip while continuously conveying the steel strip.

The disclosure of the specification, drawings, and claims of Japanese Patent Application No. 2016-240543, filed December 12, 2016, is incorporated herein by reference in its entirety.

Claims (8)

As a coating drying apparatus which coats and dry-processes a steel strip continuously,
A conveying unit for conveying the steel strip;
A coating part for coating and coating a coating material containing an organic solvent with respect to the conveyed steel strip at a coating position;
An oven for forming a heating space for drying the steel strip downstream from the painting position;
An exhaust unit for exhausting the heating space;
A concentration measuring unit for measuring an organic solvent concentration of the organic solvent in the heating space;
It is provided with a control unit for controlling the operation of the paint drying apparatus,
The control unit calculates the arrival predicted concentration based on the organic solvent concentration measured by the concentration measuring unit, and when the arrival predicted concentration is equal to or greater than a predetermined threshold concentration, the conveying unit continues the conveyance by the conveying unit. A painting drying device, which controls to stop painting accordingly. In the description of claim 1,
The said control part controls a so that the conveyance speed with respect to the said conveyance part may be slowed in addition to the painting stop by the said coating part, when the said arrival prediction density | concentration is more than the said threshold concentration. In the description of claim 1 or 2,
And a removing section for removing the paint applied to the steel strip by the coating section from an upstream side of the heating space.
The control unit, when the attained predicted concentration is equal to or greater than the threshold concentration, controls the coating to be removed by the removal unit along with the painting stop by the coating unit. In any one of Claims 1-3,
The said control part controls to perform coating stop by the said coating part, maintaining the discharge amount by the said exhaust part at the same amount, when the said arrival prediction density | concentration is more than the said threshold density | concentration. As a coating drying method of coating and drying-processing steel strip continuously,
A step for conveying the steel strip;
A coating step of applying a coating material containing an organic solvent to a coated steel strip at a coating position;
A drying step of drying the steel strip in a heating space on a downstream side from the coating position;
An exhaust step of exhausting the heating space;
A measurement step of measuring an organic solvent concentration of the organic solvent in the heating space;
An arithmetic step of calculating the arrival prediction concentration based on the organic solvent concentration measured
A painting stop step of stopping painting while continuing the conveyance of the steel strip when the attained predicted concentration is equal to or greater than a predetermined threshold concentration;
Including, paint drying method. In the description of claim 5,
The painting stop step includes a step of slowing the conveying speed of the steel strip together with stopping the painting when the attained predicted concentration is equal to or greater than the threshold concentration. In description of Claim 5 or 6,
The painting stop step includes a step of removing the coating applied to the steel strip at the coating position at an upstream side from the heating space when the reaching predicted concentration is equal to or higher than the threshold concentration. Drying method. In the description of any one of claims 5 to 7,
The painting stop step is a continuous coating drying method in which, when the attained predicted concentration is equal to or greater than the threshold concentration, the painting is stopped while maintaining the exhaust amount at the same amount.

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