JP2001227864A - Radiant drier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiant drier which is of explosion-proof structure and besides is equipped with an oil.electric radiant panel for equalizing radiant heat. SOLUTION: In a radiant drier which is so arranged as to heat and dry long sheet-shaped base material 3 impregnated with resin liquid carried within drying chambers 4 and 5 by the radiant heat a radiant panel 1, the above radiant panel 1 possesses a radiant plate 17 whose surface side serves as a radiant face in opposition to the sheet-shaped base material, a meandering passage 18 which is made on the rear side of the radiant plate 17, an MI ble 19 which serves as a heat source, being arranged within the passage 18, and a heat medium 20 which is sealed in the passage 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a radiant dryer, and mainly relates to an elongated immersion impregnated with a varnish (a thermosetting resin thinned by dissolving with a solvent or a curing agent). It is used for drying and curing a fiber sheet base material.

[0002]

2. Description of the Related Art In general, a varnish thinned by dissolving a thermosetting resin with a solvent or a curing agent is impregnated into a long sheet-like substrate made of glass fiber, paper, or the like, and then the solvent is evaporated. In the case where the curing treatment of the resin is continuously performed, an infrared (particularly far infrared) radiation dryer is widely used.

Conventional radiation dryers of this type are disclosed, for example, in JP-B-56-36352 and JP-B-63-3635.
A structure disclosed in Japanese Patent No. 3116 or the like is known. That is, each of the radiant dryers (both not shown)
In a vertically long drying chamber through which the varnish-impregnated sheet-like substrate passes, a radiant panel using heat medium oil or steam as a heat source is disposed, and the varnish-impregnated sheet-like substrate passes through the drying chamber. In the meantime, the solvent in the varnish is evaporated by the radiation heat from the radiation panel, and the thermosetting resin is partially cured.

[0004]

However, the conventional radiant dryer has the following problems because heat medium oil or steam is used as the heat source of the radiant panel. A special heating source such as a thermo-boiler or a steam boiler is required, so that a large installation space is required and the entire apparatus becomes large. Between the radiant dryer and the heating source (thermo-boiler or steam boiler), a pipe for supplying heat medium oil or steam to the radiant panel is required, and the pipe is required to keep heat. Requires multiple control valves and zone pumps. Since boilers (thermo-boilers, steam boilers) and various devices (control valves, zone pumps, etc.) are used, the initial cost of the entire apparatus increases.

[0005] In order to solve these problems, it is conceivable to use an electric infrared radiation type dryer using electricity as a heat source of the radiation panel. However, this radiant dryer
Explosion hazard when drying a varnish in which a thermosetting resin is dissolved in an organic solvent (acetone, toluene, methyl ethyl ketone, etc.) because the temperature of the infrared radiation device is high and no explosion-proof wiring cable is used. And there is a problem that it cannot be used.

[0006] The present invention has been made in view of the above-described problems. By forming a radiant panel using a MI cable, which has a proven track record for explosion-proof wiring work, as a heat source, a conventional radiant drying method is provided. The above-mentioned problems (~
It is an object of the present invention to provide a radiant dryer provided with an oil / electric radiant panel having an explosion-proof structure and uniform radiant heat.

[0007]

In order to achieve the above object, the present invention provides a method for heating a long sheet-like substrate impregnated with a resin liquid carried in a drying chamber by radiant heat from a radiant panel. In a radiant dryer that is designed to be dried, the radiant panel has a radiating plate whose front side is a radiating surface facing the sheet-like base material, and a meandering passage formed on the back side of the radiating plate. , A MI cable arranged in the passage and serving as a heating source, and a heat medium sealed in the passage.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an example of a vertical radiation dryer (dry curing oven) provided with an oil / electric radiation panel 1 according to an embodiment of the present invention. A long fiber sheet-like base material 3 impregnated with a varnish 2 obtained by dissolving a conductive resin in a solvent or a curing agent and thinning is continuously dried and cured.

The radiant dryer has an inlet 4a and an outlet 4
b, and a vertically long inlet-side drying chamber 4 into which the varnish 2 is impregnated and the sheet-like substrate 3 impregnated with the varnish 2 having the inlet 5a and the outlet 5b.
A vertical outlet-side drying chamber 5 through which water is conveyed downward, a reversing chamber 6 communicating the outlet 4b of the inlet-side drying chamber 4 with the inlet 5a of the outlet-side drying chamber 5, and a water cooling unit disposed in the reversing chamber 6. Top roll 7, an oil / electric radiant panel 1 for heating the sheet-like base material 3 conveyed in each of the drying chambers 4, 5, and provided on top of each of the drying chambers 4 and 5, respectively. A hot air supply port 8 for uniformly supplying heated hot air A (heated air) whose temperature is controlled into the drying chambers 4 and 5, and a hot air supply port 8 provided at a lower portion of each of the drying chambers 4 and 5. , 5 is provided with a hot air discharge port 9 for discharging the hot air A supplied therein, and the sheet-like base material 3 impregnated with the varnish 2 is moved from the inlet 4 a of the inlet drying chamber 4 to the inside of the inlet drying chamber 4. And rises in the inlet-side drying chamber 4 and is brought into the reversing chamber 6 from the outlet 4 b of the inlet-side drying chamber 4, and After the direction is changed by the prowl 7, it is lowered in the outlet-side drying chamber 5 through the inlet 5 a of the outlet-side drying chamber 5, and is continuously drawn to the outside from the outlet 5 b of the outlet-side drying chamber 5. I have.

In FIG. 1, reference numeral 10 denotes a panel surface temperature detector for measuring the surface temperature of the radiation panel 1;
A heat medium oil expansion tank for filling the heat medium oil to be 0, 12
Is a heat medium oil expansion pipe connected to the radiant panel 1 and the heat medium oil expansion tank 11, respectively, and 13 is an atmosphere connected to the heat medium oil expansion tank 11 to release air in the heat medium oil expansion tank 11 to the outside. An open bend tube, 14 is a liquid vat in which the varnish 2 is stored, 15 is a metalling roll for adjusting the amount of the varnish 2 impregnated into the sheet-like substrate 3, and 16 is a meandering correction roll for the sheet-like substrate 3.

FIGS. 2 to 5 show an oil / electric radiant panel 1 used in a radiant dryer. The radiant panel 1 is used for drying the inside of an inlet-side drying chamber 4 and the outlet side of a radiant dryer. The sheet-like base material 3 conveyed in the chamber 5 is disposed so as to face both surfaces. In this embodiment, each radiation panel 1 is vertically divided into two as shown in FIG. 2, and the upper radiation panel 1 and the lower radiation panel 1 can be individually temperature-controlled. It is configured to be able to.

That is, each of the radiating panels 1 has a radiating plate 17 having a front surface facing the sheet-like base material 3 and serving as a radiating surface, and a horizontal meandering passage 18 formed on the back surface of the radiating plate 17. And an MI cable 19 disposed in the passage 18 and serving as a heating source, and a heat-resistant heat medium 2 sealed in the passage 18.
0.

More specifically, the radiation plate 17 is formed of a rectangular metal plate such as a steel plate having excellent heat conductivity, and has a radiation surface (surface facing the sheet-like substrate 3). Is coated with a paint having good radiation.

The passage 18 is formed by bringing a metal corrugated plate 21 (corrugated plate 21 having the same size as the radiation plate 17) in which a meandering groove 21 a is formed by press molding into close contact with the back surface of the radiation plate 17. As shown by the broken line in FIG. 3, both sides of the groove 21a of the corrugated plate 21 and the radiation plate 17, the periphery of the radiation plate 17 and the periphery of the corrugated plate 21 are formed by seam welding W, and the passage 18 is formed. As shown in FIG. 3, it has a meandering shape in the horizontal direction. As shown in FIG. 5, a heat insulating material 22 and a heat insulating material holding plate 23 made of a metal plate for holding the heat insulating material 22 are provided on the back side of the corrugated plate 21 in close contact with each other.

Further, the MI cable 19 (Minal)
The Insulated Cable (insulated cable) has a metal rod serving as a core wire (which serves as an electric heater serving as a heating source) in the center of a metal cylinder serving as a sheath material having a diameter of 4 inches and a length of about 1 m. The metal cylinder formed by filling MgO (magnesium oxide) between metal rods is drawn out to a predetermined size, and is used as a heater for heating the radiation panel 1. This MI
The cable 19 has excellent characteristics such as heat resistance, explosion proof property, and mechanical strength.
It is a cable that complies with Article) and that is recommended for use in hazardous locations according to the guidelines for explosion-proof factory electrical equipment of the Industrial Safety Research Institute of the Ministry of Labor. Therefore, by forming the radiant panel 1 using the MI cable 19, the radiant panel 1 can have an explosion-proof structure. This MI cable 19
It is arranged in a meandering passage 18 formed between the radiating plate 17 and the corrugated plate 21 and partially and slightly loosely by a holding metal fitting 24 (clip) as shown in FIGS. The radiation plate 17 is fixed to the back surface side. Further, both ends of the MI cable 19 are out of the passage 18 from oil seal fittings 25 provided at both ends of the passage 18 and are open to the atmosphere.

By the way, the above-mentioned MI cable 19
This is set to 10 ° C.
When left in air at a temperature lower by 30 ° C., the temperature distribution in the longitudinal direction becomes non-uniform. Therefore, the MI cable 19 alone cannot be used for the radiation panel 1 of the radiation dryer in which a uniform temperature distribution is required. Therefore, in the radiant panel 1 using the MI cable 19, the MI cable 19 is disposed and fixed in the meandering passage 18 as described above, and the heat medium 20 serving as a heat equalizer is sealed in the passage 18. Thereby, the temperature distribution in the width direction of the radiation panel 1 can be made uniform.

The heat medium 20 is made of heat medium oil having excellent heat resistance, and is sealed in the entire area of the passage 18 formed between the radiation plate 17 and the corrugated plate 21. The heat medium 20 (heat medium oil) is supplied from the heat medium oil expansion tank 11 to the passage 18 via the heat medium oil expansion pipe 12. The heat medium oil expansion tank 11 is filled with heat medium oil about half, and is expanded and contracted at the time of heating / cooling of the heat medium oil by the open-to-atmosphere bend pipe 13 provided above the heat medium oil expansion tank 11. Can be absorbed. One end of the heat medium oil expansion pipe 12 is connected to the heat medium oil expansion tank 11.
The other end is connected to one end of the passage 18 of the radiation panel 1.

As shown in FIGS. 2 to 4, each of the radiation panels 1 has a thyristor-type power supply through an explosion-proof connector 26 and an explosion-proof wiring cable 27 when both ends of the MI cable 19 are in the air. The surface temperature of the radiant panel 1 is measured by a panel surface temperature measuring element 10 provided on the surface of the radiant panel 1 and connected to the control device 28 and the power supply 29. Based on the measured temperature, a thyristor type power supply control device is provided. By adjusting the power supply amount at 28, the surface temperature of the radiation panel 1 can be controlled to a predetermined temperature. Since the radiant panel 1 using the MI cable 19 is used in a hazardous area, it is necessary to provide a high-temperature alarm, an automatic heating power supply cut-off (so-called high-cut) mechanism, installation of an earth leakage breaker for earth leakage, and the like. Protection measures are in place.

Next, the varnish 2 was prepared using the above-mentioned radiation dryer.
A case in which the long fiber sheet-like base material 3 impregnated with is continuously dried and cured will be described.

The sheet-shaped substrate 3 is moved into the liquid vat 14 and impregnated with the varnish 2. After the impregnation amount of the varnish 2 is regulated by the metalling roll 15, the sheet-shaped substrate 3 is provided below the inlet-side drying chamber 4. It enters into the entrance side drying room 4 from the entrance 4a and rises in the entrance side drying room 4.

The sheet-like base material 3 rising in the inlet-side drying chamber 4 is heated by the radiant heat from the radiant panel 1 and the hot air A (heating air) supplied from the hot-air supply port 8 into the inlet-side drying chamber 4. Then, the solvent in the varnish 2 is evaporated, and the drying substantially ends at the upper part of the inlet-side drying chamber 4.

If the varnish 2 contains an organic solvent, there is a risk of explosion. However, in this radiant dryer, since the radiant panel 1 and its peripheral devices (such as the connector 26 and the wiring cable 27) have an explosion-proof structure, even if the varnish 2 contains an organic solvent, there is a danger of explosion. It can be safely driven without. Further, the radiation panel 1 has a meandering passage 18 formed on the back surface side of the radiation plate 17, an MI cable 19 serving as a heating source is arranged in the passage 18, and a heat-resistant heat medium 20 is sealed in the passage 18. Therefore, the temperature distribution on the radiation surface (the surface of the radiation plate 17) can be made uniform, and the heating and drying in the width direction of the sheet-like substrate 3 can be performed uniformly.

The surface temperature of the radiant panel 1 is controlled to a predetermined temperature by the thyristor type power supply control device 28 based on the surface temperature of the radiant panel 1 measured by the panel surface temperature measuring element 10, and is formed in a sheet shape. When a prepreg for an electrical insulating plate is manufactured using a glass cloth as the base material 3, the surface temperature of the radiation panel 1 in the entrance-side drying chamber 4 is often set to 160 ° C to 190 ° C. The hot air A supplied into the inlet-side drying chamber 4 is heated outside and controlled at a predetermined temperature, and is applied to the sheet-like base material 3 at a uniform wind speed in the width direction of the sheet-like base material 3. After flowing along, it is discharged from the hot air discharge port 9 together with the evaporated solvent. This hot air A
Not only heats the sheet-like base material 3 but also
When an organic solvent is present, the organic solvent also serves to dilute the solvent gas concentration in the inlet-side drying chamber 4 in order to keep the concentration of the organic solvent evaporated from the sheet-shaped substrate 3 below its lower limit.
The temperature of the hot air A is set to be lower by 10 ° C. to 30 ° C. than the surface temperature of the radiation panel 1.

Then, the sheet-like base material 3 which has passed through the inside of the inlet side drying chamber 4 is removed by an outlet 4 b provided above the inlet side drying chamber 4.
From the reversing chamber 6, where it is reversed by the rotating top roll 7 and fed into the outlet-side drying chamber 5 from the inlet 5 a provided above the outlet-side drying chamber 5. Descend.

The sheet-like substrate 3 descending in the outlet-side drying chamber 5 is heated by the radiant heat from the radiant panel 1 and the hot air A (heating air) supplied into the outlet-side drying chamber 5 from the hot-air supply port 8. Then, the solvent slightly remaining in the varnish 2 is evaporated, and at the same time, the curing of the thermosetting resin is promoted to be in a semi-cured state.

At this time, the radiation panel 1 of the outlet-side drying chamber 5
And its peripheral devices (such as the connector 26) also have an explosion-proof structure, so even if the varnish 2 contains an organic solvent,
No explosion hazard. Further, the radiation panel 1 includes a radiation plate 17.
Since a meandering passage 18 is formed on the back side of the device, and an MI cable 19 serving as a heating source is disposed in the passage 18 and a heat-resistant heat medium 20 is enclosed, a radiation surface (radiation plate) is formed. 17), and the heating and drying in the width direction of the sheet-shaped substrate 3 can be performed uniformly.

The surface temperature of the radiation panel 1 is controlled to a predetermined temperature by the thyristor type power supply control device 28 based on the surface temperature of the radiation panel 1 measured by the panel surface temperature measuring element 10. The hot air A supplied into the outlet-side drying chamber 5 is heated outside and controlled at a predetermined temperature, and is applied to the sheet-like base material 3 at a uniform wind speed in the width direction of the sheet-like base material 3. After flowing along, it is discharged from the hot air discharge port 9 together with the evaporated solvent. The temperature of the hot air A is set 10 ° C. to 30 ° C. lower than the surface temperature of the radiant panel 1 in the outlet-side drying chamber 5.

Then, the sheet-like base material 3 which has passed through the inside of the outlet-side drying chamber 5 is removed by an outlet 5 b
, And the process proceeds to the next step through the meandering correction roll 13 and is sequentially processed.

FIG. 6 shows another example of the oil / electric radiant panel 1. The radiant panel 1 is divided into upper and lower parts and into three parts in the width direction of the sheet-like base material 3.
A sheet-like substrate that is configured so that the temperature of each of the divided radiant panels 1 can be individually controlled, and is conveyed in the inlet-side drying chamber 4 and the outlet-side drying chamber 5 of the radiant dryer. 3 are arranged to face both surfaces. or,
Each of the radiation panels 1 has the same structure as the radiation panel 1 shown in FIG. This oil-electric radiant panel 1
Can control the heating temperature in the width direction of the sheet-shaped base material 3, so that even if the temperature in the width direction of the sheet-shaped base material 3 becomes uneven, the temperature in the width direction of the radiation panel 1 is controlled. This makes it possible to correct the variation in the temperature in the width direction of the sheet-shaped base material 3.

In the above embodiment, the explosion-proof oil / electric radiant panel 1 is used for a vertical dryer (dry curing oven). The oil / electric radiant panel 1 may be used for a horizontal or arch type dryer, or may be used for a solution dryer that does not use an organic solvent.

In the above embodiment, the oil / electric radiant panel 1 is divided vertically or vertically and horizontally as shown in FIGS. 2 and 6, but the oil / electric radiant panel 1 is divided. The form is not limited to that according to the above-described embodiment, and any division form may be used as long as the drying and curing of the sheet base material 3 impregnated with the varnish 2 can be performed uniformly. For example, although not shown, the radiation panel 1 may be vertically divided into three parts, or the radiation panel 1 may be divided into three parts vertically and divided into a plurality of parts in the left-right direction (width direction).

In the above embodiment, FIGS.
The oil / electric radiant panel 1 having a structure divided vertically or vertically and horizontally as shown in FIG. 1 is arranged in the inlet-side drying chamber 4 and the outlet-side drying chamber 5, but in other embodiments. In this case, the radiation panel 1 that is not divided may be provided in the inlet-side drying chamber 4 and the outlet-side drying chamber 5.

In the above embodiment, the oil-electric radiant panel 1 divided in the same manner is disposed in the inlet-side drying chamber 4 and the outlet-side drying chamber 5, respectively. In the embodiment, the inlet-side drying chamber 4 and the outlet-side drying chamber 5
The radiation panels 1 divided into different forms may be provided respectively. For example, a radiation panel 1 (radiation panel 1 shown in FIG. 2) divided vertically into two portions is provided in the entrance-side drying chamber 4, and a radiation panel 1 is divided vertically into two portions in the exit-side drying chamber 5, and in the left-right direction (width direction). The radiation panel 1 divided into three (radiation panel 1 shown in FIG. 6) may be provided.

In the above embodiment, the radiation panel 1
The heat insulating material 22 is arranged in close contact with the back side of the corrugated sheet 21. In other embodiments, although not shown, air is interposed between the corrugated sheet 21 and the heat insulating material 22. A layer may be provided.

In the above embodiment, a radiant dryer is provided with one heat medium oil expansion tank 11, and this heat medium oil expansion tank 11 and each radiant panel 1 are connected by a heat medium oil expansion pipe 12. Although each is connected, in another embodiment, a small heat medium oil expansion tank 11 is provided for each radiant panel 1, and each heat medium oil expansion tank 11 and each radiant panel 1 are connected to each other. The connection may be made by the medium oil expansion pipes 12.

[0036]

As is apparent from the above description, the radiation dryer of the present invention can exhibit the following excellent effects. (1) A varnish in which a thermosetting resin is dissolved in an organic solvent because an MI cable having an excellent explosion-proof property is used as a heating source of the radiant panel and a radiant panel having an explosion-proof structure is formed using the MI cable. When heating and drying, there is no danger of explosion, and the radiant dryer can be safely operated. In addition, it becomes easier to obtain the Fire Defense Law certification for radiant dryers for heating and drying varnishes containing organic solvents and for wiring work around them. (2) A radiation panel having a structure in which a meandering passage is formed on the back surface of the radiation plate whose surface is a radiation surface, an MI cable is arranged in the passage, and a heat medium serving as a heat equalizer is sealed in the passage. As a result, the temperature distribution on the radiation surface becomes uniform and the sheet-like substrate can be heated uniformly, even though the panel is an electric radiation panel. As a result, the degree of drying and hardening in the width direction of the sheet-like base material can be made uniform. (3) Since the MI cable is used as the heat source of the radiant panel, heat medium oil or steam is used as the heat source of the radiant panel. Thermo boilers and steam boilers, like conventional radiant dryers using
There is no need to require a control valve, a zone pump, etc., and it is only necessary to secure a power supply. as a result,
The apparatus can be reduced in size and the initial cost can be reduced, and a large installation space is not required. Also, since the wiring between the radiant dryer and the power supply is a wiring cable, there is a pipe to supply the radiant panel with the heat medium oil or steam as in the conventional radiant dryer using heat medium oil or steam as the heat source. There is no need to keep the heat, and piping and heat are not required, and the space can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a radiant dryer (dry curing oven) according to an embodiment of the present invention.

FIG. 2 is a schematic flow chart showing the entirety of an oil / electric radiant panel used in a radiant dryer.

FIG. 3 is a schematic front view of a main part of the radiation panel.

FIG. 4 is a schematic side view of the radiation panel shown in FIG.

FIG. 5 is a sectional view of a main part of the radiation panel.

FIG. 6 is a schematic flow chart showing another example of the oil / electric radiant panel used in the radiant dryer and showing the entire radiant panel.

[Explanation of symbols]

1 is a radiation panel, 3 is a sheet-like substrate, 4 and 5 are drying rooms,
17 is a radiation plate, 18 is a passage, 19 is an MI cable, 20
Is a heat medium.

Claims (1)

[Claims] 1. A radiant dryer in which a long sheet-like base material impregnated with a resin liquid conveyed in a drying chamber is heated and dried by radiant heat from a radiant panel. However, a radiation plate whose front side is a radiation surface facing the sheet-like base material, a meandering passage formed on the back surface side of the radiation plate, and an MI cable disposed in the passage and serving as a heating source, A radiation dryer comprising: a heat medium sealed in a passage.