JPH0628221Y2 - Internal pressure / solvent gas concentration control device in the dryer - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a dryer of a coating machine, and in particular, it controls solvent gas vaporized and evaporated in the dryer with high precision control with respect to an internal pressure set value in the dryer. The present invention relates to an internal pressure / solvent gas concentration control device for performing control to always keep the concentration of a constant value to a set value.

[Conventional technology]

Magnetic tapes such as cassette tapes and video tapes are manufactured by forming a coating film of magnetic powder, a binder, a leveling agent, etc. on a plastic base film with a coating machine. The film on which the coating film is formed is passed through a furnace of a dryer in a belt shape to be continuously dried. In recent years, thinning of magnetic tapes used and miniaturization of magnetic powders have progressed along with higher performance of devices, and fine dust and contaminants attached to the magnetic tapes pose a problem in terms of quality. For this reason, in the drying process, in order to prevent fine dust, contaminants, and the like from adhering to the coating film, the internal pressure of the dryer is controlled. For example, if the outside air of the dryer installation place is clean, the internal pressure inside the dryer may be negative, but if it is not clean, it is necessary to control the internal pressure to keep it positive so that the outside air does not enter. .

Conventionally, as the internal pressure control device of this type, a rotation speed control is performed only by the exhaust blower of the dryer, or an opening control is performed only by a damper with an opening control motor provided on the exhaust side.

Also, in order to prevent the solvent vaporized and evaporated from the coating film in the dryer to become highly concentrated and explode, it is necessary to keep the solvent gas concentration below about 1/3 of the lower explosion limit. The gas concentration was controlled by controlling the rotation speed of the exhaust blower.

[Problems to be solved by the device]

However, in the above-described rotational speed control using only the exhaust blower, in the internal pressure control for keeping the internal pressure in the dryer at the set value, the response to the deviation between the set value and the measured value is slow and this If the deviation is extremely large, there is a problem that the control range of the exhaust blower is exceeded. In particular, when the temperature inside the furnace does not reach the predetermined temperature as at the beginning of dryer operation, the pressure inside the furnace keeps rising (or decreasing) rapidly due to the difference in air density, and Until the set temperature was reached, the control range of the dryer could not be controlled because the exhaust blower did not enter the control range that was possible.

On the other hand, in the case of performing the opening control only by the damper with the opening control motor provided on the exhaust side, when controlling the internal pressure in the dryer, although the response to the deviation is fast, the internal pressure can be controlled with high accuracy. There was a problem that was not suitable.

Further, in the conventional device that controls the solvent gas concentration by the rotation speed of the exhaust blower, if the solvent gas concentration in the dryer is controlled,
There was a problem that the internal pressure changed. For this reason,
It was not possible to control to satisfy both the internal pressure and the solvent gas concentration at the same time, and either the internal pressure control or the solvent gas concentration control was often selected, that is, the drying system with higher priority was often selected and controlled. .

Therefore, the purpose of the present invention is to be able to always control the internal pressure in the dryer with high accuracy with respect to the set value, and to quickly follow the disturbance that greatly changes the internal pressure. An object of the present invention is to provide an internal pressure / solvent gas concentration control device in a dryer, which can be easily controlled so as to keep the set value constant.

[Means for Solving the Problems]

The internal pressure / solvent gas concentration control device in the dryer according to the present invention is a belt-shaped film by continuously supplying a belt-shaped film (10) whose surface has been coated, and supplying and exhausting the required warm air. It has a warm air oven for drying, and the air supply damper (31A, 31B, 31C) and circulation blower (32A, 32B, 32C) are installed in this warm air oven.
And a heater (26A, 26B, 26C) and an air film (28A, 28B, 28C) are provided to connect an air supply system (62) that circulates hot air and connects the exhaust blower (42A, 42B, 42C). In the dryer (20) configured to connect the provided exhaust system (72) to exhaust hot air, the exhaust system (72) has an exhaust blower (42A) with a variable speed control motor (44A, 44B, 44C). , 42B, 42C) and motor for opening control (48A, 48B, 48C
C) dampers (46A, 46B, 46C) are arranged in tandem, and a pressure transmitter (50A, 50B, 50C) for measuring the pressure inside the dryer is provided, while the air supply system (62) has an opening control motor (62). 33A, 33B, 33C) with an air supply damper (31A, 31B, 31C), and a gas concentration meter (52A, 42A, 42B, 42C) upstream of the exhaust blower (42A, 42B, 42C) with a motor for variable speed control of the exhaust system. 52B, 52C) is provided, and the pressure measured value by the pressure transmitter (50A, 50B, 50C) is compared with a preset pressure set value, and when the pressure measured value is outside the predetermined allowable range for the pressure set value, According to the deviation, the opening control motor (48A, 48B, 48C) is controlled to control the damper.
Correct the opening of (46A, 46B, 46C), and if the measured pressure value is within the predetermined allowable range for the pressure setting value, use the variable speed control motor (44A, 44B, 44C) according to the deviation. Control to correct the rotation speed of the exhaust blower (42A, 42B, 42C) and dryer (20)
A first controller configured to maintain a constant internal pressure is provided, and the solvent gas concentration measured value by the gas concentration meter (52A, 52B, 52C) is compared with a preset solvent gas concentration set value, and its deviation is compared. A second controller configured to correct the opening degree of the air supply damper (31A, 31B, 31C) by controlling the opening degree control motors (33A, 33B, 33C) according to To do.

[Action]

According to the internal pressure / solvent gas concentration control device in the dryer according to the present invention, the pressure in the oven of the dryer is constantly measured by the pressure transmitter, and the deviation between the measured value and the internal pressure set value is less than the predetermined deviation value. If it is too large, the damper opening of the damper with motor for controlling the opening of the exhaust system is automatically adjusted so that it falls quickly within the specified deviation value. By fixing and controlling the rotation speed of the motor for variable speed control of the exhaust blower, the internal pressure in the dryer can be controlled with high accuracy so that it is always constant with respect to the set value.

Further, according to the present invention, the solvent gas concentration in the furnace is constantly measured by a gas concentration meter provided in the middle of the exhaust duct, and the air supply with the motor for controlling the opening is adjusted so as to correct the deviation of the solvent gas concentration from the set value. The damper opening of the damper is automatically adjusted. At this time, although the internal pressure in the dryer changes, the internal pressure control in the dryer immediately detects the change in the internal pressure and performs a control operation to quickly keep the internal pressure constant. Therefore, the internal pressure and the solvent gas concentration in the dryer are simultaneously controlled and kept constant with respect to the set value.

〔Example〕

Next, an embodiment of an internal pressure / solvent gas concentration control device in a dryer according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a flow sheet showing one structural example of an internal pressure control device in a dryer applied to the present invention. First
In the figure, reference numeral 10 indicates a strip-shaped film on which a coating film of magnetic powder or the like is continuously formed on one surface by a known coating machine (not shown). This strip-shaped film 10 is introduced into the dryer 20 via the inlet side guide roll 12, is dried while passing through the inside of the dryer 20, and is appropriately guided to the outside via the outlet side guide roll 14. It is wound up and collected. The dryer 20 of this type is generally composed of a furnace divided into several zones, and the illustrated example shows a case where it comprises three zones 20A, 20B, 20C. The outside air taken in by the main air supply blower 60 passes through the air supply system piping 62, and each zone in the dryer 20.
The air is blown to the 20A, 20B, 20C by the circulation blowers 32A, 32B, 32C via the air volume adjustment air supply dampers 30A, 30B, 30C. At this time, the outside air is warmed by the heaters 26A, 26B, 26C, and then passes through the air filters 28A, 28B, 28C to remove fine dust and the like, and is blown into each zone as clean warm air. The warm air blown to each of the zones 20A, 20B, 20C is distributed by furnace piping (not shown), and jetted toward the strip-shaped film 10 from a large number of jet nozzles 22A, 22B, 22C, respectively. Dry the solvent of the top coating. This warm air can be fed back to the circulation blowers 32A, 32B, 32C in each zone via the circulation pipes 24A, 24B, 24C.
The hot air blowing nozzles 22A, 22B, 22C are also arranged on the lower surface side of the film 10 in order to pass the film 10 through the furnace in a non-contact state and to facilitate drying. In addition,
The wind velocity from the jet nozzle may be slow in the inlet side zone 20A and high in the zones 20B and 20C closer to the end of the flow, depending on the dryness of the solvent. Each zone 20A, 20
The internal pressure of the furnace at B, 20C is constantly measured by an electric type differential pressure transmitter (hereinafter referred to as pressure transmitter) 50A, 50B, 50C, and the hot air inside the furnace can be exhaust ducts 40A, 40B, 40C. Shift control motor 4
Exhaust air is exhausted by the main exhaust blower 70 via exhaust blowers 42A, 42B, 42C having 4A, 44B, 44C, dampers 46A, 46B, 46C having opening control motors 48A, 48B, 48C, and exhaust system piping 72.

Next, the internal pressure control operation of the dryer 20 thus configured will be described with reference to FIGS. 1 and 2. Second
FIG. 1 is a schematic flow sheet of a first controller that controls the control device shown in FIG. Immediately after the start of operation of the dryer 20, since the furnace temperature has not reached a predetermined temperature,
The furnace pressure rapidly rises (or falls) due to the difference in air density
As it is, the inside of the furnace has a large deviation ε between the internal pressure set value and the internal pressure set values (internal pressure feedback values) from the pressure transmitters 50A, 50B, 50C. The first controller controls the internal pressure for each zone against this deviation,
Here, the zone 20A will be described as an example. The internal pressure set value and the internal pressure feedback value from the pressure transmitter 50A are input to the PI controller 80 as a deviation ε in the first controller,
The output value obtained by the proportional integration processing of this deviation ε is input to the arithmetic units 82 and 86 in the first controller and processed together with the internal pressure set value. However, it is input to the computing unit 86 via the normally open contact 84. The calculator 82 outputs a rotation speed command to the variable speed control motor 44A of the exhaust blower 42A which performs predetermined calculation processing, and the calculator 86 opens the opening control motor 48A of the opening control motor damper 46A. Output a command. The motor rotation speed command is also output to the calculator 86. Further, the damper opening data of the opening control motor-equipped damper 46A is input to the calculator 82.

It should be noted that the first controller stores in advance automatic measurement data of the relationship between the opening of the damper with the opening control motor and the motor speed of the exhaust blower and the internal pressure. This opening-
The arithmetic units 82 and 86 perform predetermined arithmetic processing based on the data of the number of revolutions and the internal pressure.

If the deviation ε is equal to or larger than a predetermined deviation value (for example, 5 mmAq), the first controller 84 normally opens the contact 84.
Then, the internal pressure set value and the output value of the PI adjuster 80 corresponding to the deviation ε are input to the calculator 86. The arithmetic unit 86 performs arithmetic processing based on the data of the relationship between the opening degree-rotation speed-internal pressure so that the deviation ε becomes small, and outputs an opening degree command to the opening control motor-equipped damper 46A. The pressure inside the furnace in zone 20A is rapidly adjusted roughly. While the deviation ε is large,
Even if a rotation speed command is output to the variable speed control motor 44 of the exhaust blower 42A by 82, there is no effect because it is not within the internal pressure control area of the exhaust blower 42A. With the coarse adjustment by the damper 46A with motor for controlling the opening, the deviation ε between the internal pressure set value and the internal pressure feedback value can be quickly set to the predetermined deviation value of 5 mm.
Since it becomes less than Aq and enters the internal pressure control area of the exhaust blower 42A, the damper opening of the damper 46A with a motor for opening control is fixed, and the variable speed control of the exhaust blower 42A according to the motor speed command from the calculator 82. The rotation speed of the motor 44A is controlled. Thus, the exhaust blower 42A performs fine adjustment so that the internal pressure feedback value matches the internal pressure set value. In other words, by combining the advantages of both the rough but speedy internal pressure control by the damper 46A with the motor for controlling the opening and the highly accurate internal pressure control by the exhaust blower 42A with the motor for controlling the variable speed, the reaction is slow. Achieves quick and highly accurate internal pressure control in zone 20A.

The same internal pressure control is performed by the first controller also in the zones 20B and 20C, the constant internal pressure can be maintained quickly and with high accuracy, and the adverse effects of the internal pressures in the respective zones interfering with each other can be eliminated.

With the internal pressure control device according to this configuration example, the set value for the internal pressure of the furnace + 0.
It is possible to easily realize control in which the measured value is within a deviation of +0.5 to 1 mmAq with respect to 5 mmAq.

Next, an embodiment of the internal pressure / solvent gas concentration control device in the dryer according to the present invention to which this internal pressure control device is applied will be described in detail with reference to FIGS. 3 and 4.

FIG. 3 is a flow sheet diagram showing an embodiment of the internal pressure / solvent gas concentration control device in the dryer according to the present invention.
The figure is a flow sheet diagram of the second controller for controlling the solvent gas concentration. In this embodiment, the same components as those of the apparatus shown in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

That is, in FIG. 3, in addition to the constant furnace pressure control,
In order to control the concentration of the solvent gas vaporized and evaporated in the oven of the dryer 20 to be constant, the air flow rate adjustment air supply dampers 30A, 30B, 30C in FIG. 1 are respectively controlled by the opening control motors 33A, 33B, 33C.
Change to air supply damper 31A, 31B, 31C with, and each zone 2
The difference is that gas concentration meters 52A, 52B, 52C are newly installed in the middle of the exhaust ducts 40A, 40B, 40C of 0A, 20B, 20C. The second controller controls the internal pressure / solvent gas concentration for each of the zones 20A, 20B, 20C, but here the zone 20A will be described as an example.

In order to prevent the risk that the vaporized and evaporated solvent generated during the drying process of the coating film on the strip-shaped film 10 becomes highly concentrated in the furnace and explodes, the outside air is supplied from the air supply system into the furnace and the solvent gas concentration becomes the lower limit of explosion. Control so that it is less than about 1/3.
The second controller inputs the deviation ε'between the gas concentration feedback value and the gas concentration set value by the gas concentration meter 52A installed in the middle of the exhaust duct 40A into the PI controller 81, and the deviation ε'is proportionally integrated. Input the output value together with the gas concentration set value into the motor 33A for controlling the opening of the air supply damper 31A as a damper opening command of the motor, and automatically adjust the opening of the air supply damper 31A so that the deviation ε'is reduced. , The air volume into the furnace of zone 20A is controlled, and the solvent gas concentration is controlled to be constant. At this time, the pressure in the furnace changes instantaneously, but since the internal pressure control device described above is also used, the pressure transmitter 50
A immediately detects internal pressure and damper 4 with motor for controlling opening
By controlling the damper opening of 6A and the rotation speed of the exhaust blower 42A with a variable speed control motor, the internal pressure can be quickly and accurately maintained constant with respect to the set value.

The same internal pressure / solvent gas concentration control is performed in the zone inside the dryer 20.
20B and 20C will also be held.

[Effect of device]

As is apparent from the above-described embodiments, according to the device of the present invention, the damper opening control by the damper with the opening control motor installed on the exhaust side and the rotation speed control by the exhaust blower with the variable speed control motor are predetermined. Since the deviation is used as a boundary condition for automatic switching and control is performed based on the opening-rotation speed-internal pressure data that is automatically measured and stored in the first controller in advance, the controllability of both can be utilized, so The internal pressure control can be quickly and highly accurately controlled with respect to the set value.

Therefore, like a coating machine, even when the inside of the dryer is generally separated into several zones, it is possible to control with high accuracy the same internal pressure set value in all zones,
Since there is no backflow of air due to interference between the zones, it is possible to stabilize the running of the strip film passing through the furnace.

Particularly, according to the internal pressure / solvent gas concentration control device in the dryer according to the present invention, the measured value by the gas concentration meter installed in the middle of the exhaust duct is fed back to the second controller to control the opening so that the concentration is set. The concentration of the solvent gas can be controlled to a constant level by a simple control that automatically adjusts the damper opening of the air supply damper with a motor for use, and the internal pressure can be quickly maintained to a set value by using the internal pressure control device together. be able to.

Although the preferred embodiment of the present invention has been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of the internal pressure control device in the dryer applied to the present invention, FIG. 2 is a control system diagram of the first controller for performing the internal pressure control of FIG. 1, and FIG. FIG. 4 is a system diagram showing an embodiment of an internal pressure / solvent gas concentration control device for a dryer according to the present invention, and FIG. 4 is a control system diagram of a second controller for performing gas concentration control in FIG. 10 …… Band-shaped film 12 …… Inlet side guide roll 14 …… Outlet side guide roll, 20 …… Dryer 20A, 20B, 20C …… Zone 22A, 22B, 22C …… Nozzle 24A, 24B, 24C …… For circulation Piping 26A, 26B, 26C …… Heater 28A, 28B, 28C …… Air filter 30A, 30B, 30C …… Air supply damper 31A, 31B, 31C …… Air supply damper with opening control motor 32A, 32B, 32C …… Circulation blower 33A, 33B, 33C ...... Opening control motor 40A, 40B, 40C ...... Exhaust duct 42A, 42B, 42C ...... Exhaust blower with variable speed control motor 44A, 44B, 44C ...... Variable speed control motor 46A, 46B, 46C …… Damper with motor for opening control 48A, 48B, 48C …… Motor for opening control 50A, 50B, 50C …… Electric differential pressure transmitter (pressure transmitter) 52A, 52B, 52C… … Gas concentration meter 60 …… Main air supply blower, 62 …… Air supply system piping 70 …… Main exhaust blower, 72 …… Exhaust system piping 80,81 …… PI controller, 82,86 …… Calculator 84… … Normally open contact

Claims (1)

[Scope of utility model registration request] 1. A strip-shaped film (10) having a surface coated with a coating film.
Has a hot air oven for drying the strip film by supplying and exhausting the required hot air, and the air supply damper (31A, 31B, 31C) and the circulation blower (32A ,
32B, 32C), heater (26A, 26B, 26C) and air filter (28A, 28C)
B, 28C) and an air supply system (62) for circulating hot air, and an exhaust system equipped with an exhaust blower (42A, 42B, 42C)
Dryer (2) configured to connect (72) to exhaust hot air
In (0), the exhaust system (72) has an exhaust blower (42A, 42B, 42C) with a variable speed control motor (44A, 44B, 44C) and an opening control motor (48A, 48B, 48C).
C) dampers (46A, 46B, 46C) are arranged in tandem, and a pressure transmitter (50A, 50B, 50C) for measuring the pressure inside the dryer is provided, while the air supply system (62) has an opening control motor (62). 33A, 33B, 33C) with an air supply damper (31A, 31B, 31C), and a gas concentration meter (52A, 42A, 42B, 42C) upstream of the exhaust blower (42A, 42B, 42C) with a motor for variable speed control of the exhaust system. 52B, 52C) is provided, and the pressure measured value by the pressure transmitter (50A, 50B, 50C) is compared with a preset pressure set value, and when the pressure measured value is outside the predetermined allowable range for the pressure set value, According to the deviation, the opening control motor (48A, 48B, 48C) is controlled to control the damper.
Correct the opening of (46A, 46B, 46C), and if the measured pressure value is within the predetermined allowable range for the pressure setting value, use the variable speed control motor (44A, 44B, 44C) according to the deviation. Control to correct the rotation speed of the exhaust blower (42A, 42B, 42C) and dryer (20)
A first controller configured to maintain a constant internal pressure is provided, and the solvent gas concentration measured value by the gas concentration meter (52A, 52B, 52C) is compared with a preset solvent gas concentration set value, and its deviation is compared. A second controller configured to correct the opening degree of the air supply damper (31A, 31B, 31C) by controlling the opening degree control motors (33A, 33B, 33C) according to Internal pressure / solvent gas concentration control device inside the dryer.