JP6741295B2 - Dryer - Google Patents

Description

Embodiments of the present invention relate to a drying device.

In a drying device equipped with a burner as a heat source, the material to be dried is dried by using the combustion gas generated in the burner as a drying gas. As such a drying device, there is a circulation type drying device which dries an object to be dried with a drying gas from a burner and then returns the drying gas to the burner.

Generally, a circulation type drying device includes a burner that generates a drying gas and a drying chamber that introduces the drying gas from the burner and dries an object to be dried arranged inside. In a conventional drying chamber of a circulation type drying apparatus, there is one in which a drying gas is ejected from an ejection nozzle toward an object to be dried.

In order to jet the drying gas from the jet nozzle to properly heat the material to be dried, the flow velocity and temperature of the drying gas at the time of collision with the material to be dried are important factors. For example, when the flow velocity of the drying gas when it collides with the object to be dried is constant, the amount of heat received by the object to be dried changes depending on the temperature of the drying gas when it collides with the object to be dried. The higher the temperature of the drying gas when it collides with the object to be dried, the larger the amount of heat received by the object to be dried.

Therefore, when the flow velocity of the drying gas is constant, in order to keep the amount of heat received by the object to be dried constant, it is necessary to keep the temperature of the drying gas constant when it collides with the object to be dried. Then, by keeping the amount of heat received by the object to be dried constant, it is possible to stably raise the temperature of the object to be dried.

In the conventional circulation type drying device having a jet nozzle, the drying gas generated in the burner is introduced into a duct having a jet nozzle arranged in the drying chamber. Then, the drying gas introduced into the duct is ejected from the ejection nozzle toward the object to be dried.

In this conventional circulating dryer, the flow rate of fuel supplied to the burner is adjusted based on the temperature of the drying gas discharged from the burner. Here, the temperature of the drying gas discharged from the burner is almost the same as the temperature of the drying gas ejected from the ejection nozzle.

In the conventional circulation type drying device, during the start-up operation from the start of operation, the drying gas discharged from the burner, that is, the temperature of the drying gas ejected from the ejection nozzle reaches the set temperature, Increase fuel flow. Then, when the temperature of the drying gas ejected from the ejection nozzle reaches the set temperature, it is determined that the startup operation has ended. Then, in the subsequent operation, adjustment of the fuel flow rate, that is, temperature adjustment is started so that the temperature of the drying gas ejected from the ejection nozzle is maintained at the set temperature.

Japanese Patent No. 4701224

As described above, in the conventional circulation type drying device, when the temperature of the drying gas ejected from the ejection nozzle reaches the set temperature after the operation is started, adjustment for maintaining the set temperature is performed. To do. In such temperature adjustment, even if the temperature of the drying gas ejected from the ejection nozzle reaches the set temperature, the temperature of the gas in the atmosphere inside the drying chamber does not reach the set temperature.

Here, in the above-described circulation type drying device, the drying gas ejected from the ejection nozzle reaches the object to be dried while entraining the gas in the atmosphere in the drying chamber. Therefore, the temperature of the drying gas when it reaches the object to be dried is lower than the temperature of the drying gas when it is ejected from the ejection nozzle.

That is, in the conventional circulation type drying device, the temperature of the drying gas when reaching the material to be dried is the temperature when the gas is ejected from the ejection nozzle until the temperature of the gas in the atmosphere in the drying chamber reaches the set temperature. Lower than the temperature of the working gas.

On the other hand, when controlling with the temperature of the drying gas ejected from the ejection nozzle in the conventional circulation type drying device, even if the temperature of the gas in the atmosphere in the drying chamber is lower than the set temperature, the drying ejected from the ejection nozzle When the temperature of the working gas reaches the set temperature, it is determined that the start-up operation has ended, and the operation mode is switched to start drying the material to be dried.

In this way, when the temperature of the gas in the atmosphere in the drying chamber is lower than the set temperature, the amount of heat required for the material to be dried cannot be given.

The problem to be solved by the present invention is to provide a drying device capable of maintaining a constant amount of heat to be received from a drying gas and stably raising the temperature of the object to be dried to a predetermined temperature. It is in.

The drying device according to the embodiment includes a combustion chamber having a burner, a drying chamber for drying an object to be dried by a drying gas discharged from the combustion chamber, and a drying chamber disposed in the drying chamber and discharged from the combustion chamber. Duct for introducing the gas for use, a jet nozzle arranged in the duct for ejecting the drying gas toward the object to be dried, and the drying gas in the drying chamber for drying the object to be dried into the combustion chamber A return pipe for guiding, a return gas temperature detection unit for detecting the temperature of the drying gas flowing in the return pipe, an ejection gas temperature detection unit for detecting the temperature of the drying gas ejected from the ejection nozzle, and from the start of operation. Until the temperature of the drying gas flowing in the return pipe reaches a predetermined temperature, the output of the burner is adjusted based on the detection signal detected by the return gas temperature detection unit, and the drying gas flowing in the return pipe is adjusted. After the temperature of the gas reaches the predetermined temperature, the control unit adjusts the output of the burner based on the detection signal detected by the jet gas temperature detection unit.

ADVANTAGE OF THE INVENTION According to the drying device of this invention, the amount of heat received by the drying gas received from the drying gas can be maintained constant, and the temperature of the drying target can be stably raised to a predetermined temperature.

It is the figure which showed the outline of the drying device of embodiment typically. It is a flowchart of the temperature control process of the drying space of the drying chamber at the time of the start-up operation of the drying device of the embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram schematically showing an outline of a drying device 10 according to an embodiment.

As shown in FIG. 1, the drying device 10 includes a combustion chamber 20, a drying chamber 60 for drying the material W to be dried by the drying gas discharged from the combustion chamber 20, and a controller 90 for controlling the drying device 10. Equipped with. The drying device 10 is a circulation type drying device in which the combustion gas generated in the combustion chamber 20 is introduced into the drying device 10 and a part of the combustion gas introduced into the drying device 10 is returned to the combustion chamber 20.

The combustion chamber 20 is a housing having an internal space. A burner 30 is provided at one end 20a of the combustion chamber 20. Combustion gas generated by burning fuel and air in the burner 30 spreads inside the combustion chamber 20. This combustion gas functions as a drying gas for drying the material to be dried W.

The other end 20b of the combustion chamber 20 has an outlet opening (not shown) for discharging the internal combustion gas. On the other end 20b side in the combustion chamber 20, for example, as shown in FIG. 1, a filter 21 is provided over the cross section.

The filter 21 removes foreign matter in the combustion gas flowing toward the outlet opening. As the filter 21, for example, a porous body, a non-woven fabric, a mesh material or the like is used. These are composed of, for example, synthetic fibers or metal fibers. Examples of the foreign matter include dust in the air, iron powder, paint, and the like.

The burner 30 includes a casing 31, a flame stabilizer 32, a fuel supply system 40, and an air supply system 50.

The casing 31 is formed of a housing and is fixed so as to penetrate the one end 20 a of the combustion chamber 20. The combustion chamber 20 side of the casing 31 is open, and a flame stabilizer 32 is provided in this opening.

The flame stabilizer 32 holds the flame and maintains stable combustion. A flame is formed on the downstream side of the flame stabilizer 32.

The fuel supply system 40 includes a fuel supply pipe 42 that supplies the fuel (gas fuel) supplied from the fuel supply source 41 into the burner 30. One end of the fuel supply pipe 42 is connected to the burner 30, and the other end is connected to the fuel supply source 41.

A fuel flow rate adjusting valve 43 for adjusting the flow rate of the fuel supplied to the burner 30 is interposed in the fuel supply pipe 42. Further, cutoff valves 44 and 45 that cut off the flow of fuel in the fuel supply pipe 42 are interposed in the fuel supply pipe 42 so as to sandwich the fuel flow rate adjustment valve 43, for example.

Further, for example, a fuel flow meter 46 for detecting the flow rate of the fuel flowing through the fuel supply pipe 42 is interposed between the shutoff valve 45 and the fuel supply source 41.

The air supply system 50 supplies the air supplied from the air source into the burner 30. Here, an example in which the intake fan 51 is provided as an air source is shown. In the intake fan 51, the flow rate of air supplied to the burner 30 is adjusted by controlling the fan motor 52 to adjust the fan rotation speed, for example.

The intake fan 51 is provided with, for example, a fan revolution counter 53 that detects the number of revolutions of the intake fan 51. The intake fan 51 is composed of, for example, a sirocco fan or a turbo fan.

Here, an example in which the intake fan 51 is provided as an air source is shown, but the air source may be any one that supplies air to the burner 30. Even when another air source is used, a flow rate adjusting unit that adjusts the flow rate of the air supplied to the burner 30 and a flow meter that detects the flow rate of the air supplied to the burner 30 are provided.

Here, the combustion method of the burner 30 is not particularly limited, and may be a diffusion combustion method or a premixed combustion method.

In the diffusion combustion method, the flame stabilizer 32 is supplied with fuel and air separately. Then, the fuel and the air are mixed and burned on the downstream side of the flame stabilizer 32, and a diffusion flame is formed on the downstream side of the flame stabilizer 32.

In the case of the premixed combustion method, for example, the fuel and the air are mixed in the casing 31 and guided to the flame stabilizer 32. Then, a premixed flame is formed on the downstream side of the flame stabilizer 32.

The drying chamber 60 dries the article to be dried W with the drying gas discharged from the combustion chamber 20. The drying chamber 60 is linearly extended, for example, as shown in FIG. Note that FIG. 1 is a view of a horizontal cross section of the drying chamber 60 as viewed from above.

The drying chamber 60 includes a casing 61, a transfer device 62, a duct 70, and a jet nozzle 71.

The casing 61 constitutes the outer shell of the drying chamber 60. When the drying chamber 60 extends linearly as shown in FIG. 1, the casing 61 has a tubular shape.

The transport device 62 moves the material W to be dried in the drying chamber 60. The transfer device 62 is provided at the center of the drying chamber 60 in the width direction and extends in the extending direction of the drying chamber 60. The transport device 62 is configured by, for example, a conveyor chain or the like. An article to be dried W is placed on the carrier device 62.

The ducts 70 are provided on both sides in the drying chamber 60 so as to sandwich the transport device 62, for example, in the extending direction of the drying chamber 60. The duct 70 has, for example, a housing shape with a hollow inside. In addition, although an example in which the two ducts 70 are arranged to face each other is shown here, the duct 70 may be only one of them.

Further, as the duct 70, an example provided along the side wall of the casing 61 of the drying chamber 60 is shown, but the duct 70 is not limited to this arrangement configuration. For example, the duct 70 may be provided above or below the article W to be dried.

A jet nozzle 71 is provided on the surface of the duct 70 on the side of the transport device 62. For example, as shown in FIG. 1, the ejection nozzles 71 are arranged at equal intervals in the extending direction of the drying chamber 60. The ejection nozzle 71 is a cylindrical body having open ends.

The ejection nozzle 71 communicates with the inside of the duct 70 and ejects the drying gas introduced into the duct 70 into the drying space 63 on the side of the transfer device 62. Then, the drying gas ejected from the ejection nozzle 71 collides with the article to be dried W on the transfer device 62. The passage sectional shape of the ejection nozzle 71 (the sectional shape perpendicular to the axial direction of the ejection nozzle 71) is not particularly limited. Examples of the passage cross-sectional shape of the ejection nozzle 71 include a circle and a rectangle.

In FIG. 1, as described above, the arrangement configuration of the ejection nozzles 71 in a predetermined horizontal section is shown. Such an ejection nozzle 71 may be arranged in a plurality of stages in the height direction of the duct 70 (direction perpendicular to the paper surface of FIG. 1).

The duct 70 communicates with the combustion chamber 20 via an introduction pipe 80. One end of the introduction pipe 80 is connected to an outlet opening (not shown) of the combustion chamber 20, and the other end of the introduction pipe 80 is connected to the duct 70. When the two ducts 70 are provided as shown in FIG. 1, the introduction pipe 80 is bifurcated so as to be connected to the respective ducts 70.

Here, the connection position of the introduction pipe 80 with the duct 70 is not particularly limited, and is set so that the flow of the drying gas in the duct 70 becomes uniform. That is, the connection position of the introduction pipe 80 with the duct 70 is set such that the flow velocity (flow rate) of the drying gas ejected from each ejection nozzle 71 is constant.

Further, the connecting portion of the introduction pipe 80 with the duct 70 is not limited to one location, and may be a plurality of portions. When there are a plurality of connecting portions, the other end side of the introduction pipe 80 is branched into a plurality.

Note that each of the bifurcating introduction pipes 80 may be provided with, for example, a flow rate adjusting valve for adjusting the flow rate of the drying gas introduced into the duct 70. In this case, the flow rate adjusting valve is controlled by the control unit 90.

In order to introduce the drying gas from the combustion chamber 20 to the duct 70 through the introduction pipe 80 and to return the drying gas from the drying chamber 60 to the combustion chamber 20 through the return pipe 85, which will be described later, in the introduction pipe 80. The circulation fan 81 is interposed.

In the circulation fan 81, the flow rate of the drying gas supplied to the duct 70 is adjusted by controlling the fan motor 82 to adjust the fan rotation speed, for example. In addition, the circulation fan 81 is provided with, for example, a fan revolution counter 83 that detects the number of revolutions of the circulation fan 81. The circulation fan 81 is composed of, for example, a sirocco fan or a turbo fan.

For example, by controlling the rotation speed of the circulation fan 81, the speed (flow rate) of the drying gas ejected from the ejection nozzle 71 is adjusted.

Here, as shown in FIG. 1, the branch pipe 100 is branched from the introduction pipe 80 between the circulation fan 81 and the branch portion 80a where the introduction pipe 80 is bifurcated. The branch pipe 100 discharges a part of the drying gas flowing through the introduction pipe 80 into the atmosphere.

The branch pipe 100 is provided with a flow rate adjusting unit 101 for adjusting the flow rate of the drying gas to be exhausted. The flow rate adjusting unit 101 is composed of, for example, a damper. This damper may be manually adjusted or controlled by the control unit 90.

Here, an example of a damper that is manually adjusted in advance is shown. The damper is adjusted so that, for example, a constant flow rate of the drying gas is discharged into the atmosphere.

The drying space 63 of the drying chamber 60 communicates with the combustion chamber 20 via a return pipe 85. One end of the return pipe 85 is connected to the casing 61 so as to communicate with the drying space 63 of the drying chamber 60. One end of the return pipe 85 is connected to the upper portion of the casing 61 so as to communicate with the drying space 63 of the drying chamber 60, for example.

The return pipe 85 is arranged so as not to penetrate the duct 70. That is, the return pipe 85 is arranged so as not to come into contact with the drying gas flowing in the duct 70. Here, one end of the return pipe 85 may be branched into a plurality of portions to suck the drying gas from a plurality of positions in the drying space 63.

A branch pipe 86 that branches from the return pipe 85 is provided on the other end side of the return pipe 85. One end of the branch pipe 86 is open to the atmosphere, for example. The branch pipe 86 is a pipe for introducing the atmosphere (air) into the drying gas that returns from the drying chamber 60 to the combustion chamber 20 via the return pipe 85. That is, the atmosphere is sucked from the end of the branch pipe 86 on the atmosphere open side and introduced into the return pipe 85.

The branch pipe 86 is provided with a flow rate adjusting unit 87 for adjusting the flow rate of the air introduced into the return pipe 85. The flow rate adjusting unit 87 is composed of, for example, a damper. This damper may be manually adjusted or controlled by the control unit 90.

Here, an example of a damper that is manually adjusted in advance is shown. The damper is adjusted so that a constant flow rate of air is introduced into the return pipe 85, for example.

The other end of the return pipe 85 is connected to the side wall of the combustion chamber 20. The side wall position to which the other end of the return pipe 85 is connected is, for example, as shown in FIG. 1, in the longitudinal direction of the combustion chamber 20 (the direction from the one end 20a side to the other end 20b side of the combustion chamber 20) the filter 21. And the burner 30 are set. As a result, when the drying gas circulated in the combustion chamber 20 through the return pipe 85 is introduced again from the combustion chamber 20 into the introduction pipe 80, foreign matter is removed through the filter 21.

Here, in the passage of the ejection nozzle 71 of the drying chamber 60, a temperature detection unit 72 that detects the temperature of the drying gas ejected from the ejection nozzle 71 is provided. The temperature detector 72 is composed of, for example, a thermocouple. The temperature detector 72 functions as a jet gas temperature detector.

The temperature detector 72 may be provided in the duct 70, for example. In this case, the temperature detector 72 detects the temperature of the drying gas flowing in the duct 70. Here, the temperature of the drying gas in the duct 70 is substantially equal to the temperature of the drying gas flowing through the passage of the jet nozzle 71. Therefore, the temperature of the drying gas flowing in the duct 70 can be regarded as the temperature of the drying gas ejected from the ejection nozzle 71.

Further, the temperature detecting units 72 may be provided at a plurality of places. Then, the average temperature calculated based on the output from each temperature detection unit 72 may be used as the temperature of the drying gas ejected from the ejection nozzle 71.

A temperature detection unit 88 that detects the temperature of the drying gas returned into the combustion chamber 20 is provided in the passage of the return pipe 85. The temperature detector 88 is composed of, for example, a thermocouple. Considering the heat loss in the return pipe 85, the temperature detection unit 88 is preferably provided, for example, on the side of the return pipe 85 near the drying chamber 60. The temperature detector 88 functions as a return gas temperature detector.

Here, the drying gas flowing through the passage of the return pipe 85 on the upstream side (drying chamber 60 side) of the position where the air is introduced through the branch pipe 86 is the drying gas in the drying space 63 of the drying chamber 60. Is almost equal to the temperature of. Therefore, the temperature of the drying gas flowing through the passage of the return pipe 85 on the upstream side (drying chamber 60 side) of the position where the air is introduced through the branch pipe 86 is regarded as the temperature of the drying gas in the drying space 63. be able to.

By detecting the temperature of the drying gas sucked from the inside of the drying space 63 through the return pipe 85 by the temperature detection unit 88, the drying inside the drying space 63 is performed rather than measuring the temperature of the drying gas at one point. A value close to the average temperature of the working gas can be detected.

Further, for example, by branching one end of the return pipe 85 into a plurality and sucking the drying gas from a plurality of positions in the drying space 63, the temperature detecting unit 88 detects a value closer to the average temperature in the drying space 63. can do.

The control unit 90 mainly includes, for example, an arithmetic unit (CPU), a storage unit such as a read-only memory (ROM) and a random access memory (RAM), and an input/output unit. The CPU executes various kinds of arithmetic processing using, for example, a program or a database stored in the storage means. The process executed by the control unit 90 is realized by, for example, a computer device such as a microcomputer.

The input/output unit inputs an electric signal from an external device or outputs an electric signal to the external device. Specifically, the output/input means is, for example, the fuel flow rate adjusting valve 43, the shutoff valves 44, 45, the fuel flow meter 46, the fan motors 52, 82, the fan speed meters 53, 83, the temperature detecting sections 72, 88, and the like. And various signals can be input and output.

The input/output unit is connected to each device of the burner 30 such as an igniter (not shown) and each device of the drying chamber 60 such as the transport device 62 so that various signals can be input/output. Further, the input/output means is connected to an operation panel (not shown) for performing input operations such as start and stop of driving so that various signals can be input/output.

The storage means stores, for example, a database of the set rotation speed of the intake fan 51 with respect to the fuel flow rate. Further, the storage means stores, for example, various databases for controlling the burner 30 and the drying chamber 60.

The control unit 90 controls, for example, the fuel flow rate adjustment valve 43, the fan motor 52, and the like based on the output signals from the temperature detection units 72 and 88, for example. The control in the control unit 90 is not limited to these. The control unit 90 can control the entire operation of the drying device 10, for example.

Next, the operation of the drying device 10 will be described.

Here, the operation during the start-up operation from the start of the operation of the drying device 10 to the time when the drying target W can be dried will be mainly described.

When the control unit 90 determines that an operation start signal is input from an external switch such as an operation panel (not shown), the control unit 90 operates the intake fan 51 and the circulation fan 81.

The outside air is supplied to the burner 30 by operating the intake fan 51. Further, by operating the circulation fan 81, the air in the burner 30 is introduced into the duct 70 of the drying chamber 60 via the introduction pipe 80. At this time, a predetermined amount of the air flowing through the introduction pipe 80 is discharged into the atmosphere via the branch pipe 100.

The air introduced into the duct 70 is ejected from the ejection nozzle 71 into the drying space 63. Further, since the air in the combustion chamber 20 is sucked by the circulation fan 81, the pressure in the combustion chamber 20 becomes lower than the pressure in the drying space 63 of the drying chamber 60. Therefore, the air in the drying space 63 is guided to the combustion chamber 20 through the return pipe 85.

At this time, air is also sucked from the end of the branch pipe 86 on the atmosphere open side. Then, a predetermined amount of air is introduced into the return pipe 85 via the branch pipe 86.

Subsequently, the control unit 90 operates the igniter (not shown) of the burner 30. Then, the control unit 90 opens the shutoff valves 44 and 45, opens the fuel flow rate adjusting valve 43 to a predetermined opening degree, and supplies the fuel (gas fuel) to the burner 30.

By opening the shutoff valves 44 and 45 and the fuel flow rate adjusting valve 43, fuel is supplied from the fuel supply source 41 to the burner 30 through the fuel supply pipe 42. When the fuel passes through the fuel supply pipe 42, the flow rate of the fuel is measured by the fuel flow meter 46 and the flow rate is adjusted by the fuel flow rate adjusting valve 43.

The air and fuel introduced into the burner 30 are guided to the flame stabilizer 32 and ignited by the igniter. At the time of ignition, the control unit 90 outputs a control signal to the fan motor 52 and the fuel flow rate adjusting valve 43 based on the database related to ignition stored in the storage means. As a result, the burner 30 is supplied with the optimum fuel flow rate and air flow rate for ignition.

Further, the control unit 90, based on the database related to ignition, the output signal from the fuel flow meter 46, and the output signal from the fan speed meter 53, which are stored in the storage means, set fuel flow rate and set air flow rate at ignition. The fuel flow rate adjusting valve 43 and the fan motor 52 are controlled so that

When combustion in the burner 30 starts, the drying gas (combustion gas) in the burner 30 is sucked into the introduction pipe 80 by the suction of the circulation fan 81. The drying gas sucked into the introduction pipe 80 is introduced into the duct 70 of the drying chamber 60. At this time, a predetermined amount of the drying gas flowing through the introduction pipe 80 is discharged into the atmosphere via the branch pipe 100.

Here, the control unit 90 controls the fan motor 82 based on the output signal from the fan revolution counter 83 so that the flow velocity of the drying gas ejected from the ejection nozzle 71 becomes the set flow velocity.

The drying gas introduced into the duct 70 is ejected from the ejection nozzle 71 into the drying space 63. Further, since the drying gas in the combustion chamber 20 is sucked by the circulation fan 81, the pressure in the combustion chamber 20 becomes lower than the pressure in the drying space 63 of the drying chamber 60. Therefore, the drying gas in the drying space 63 is guided to the combustion chamber 20 through the return pipe 85.

At this time, as described above, air is also sucked from the end portion of the branch pipe 86 on the atmosphere open side. Then, a predetermined amount of air is introduced into the return pipe 85 via the branch pipe 86 and is introduced into the combustion chamber 20.

The drying gas and air introduced into the combustion chamber 20 through the return pipe 85 mix with the combustion gas generated by the combustion in the burner 30, are sucked into the introduction pipe 80, and are introduced into the duct 70 of the drying chamber 60. It

Thus, a part of the drying gas generated in the combustion chamber 20 is circulated to the combustion chamber 20 via the drying chamber 60.

Here, the flow rate of the air introduced through the branch pipe 86 is the same as the flow rate of the combustion gas discharged into the atmosphere through the branch pipe 100.

Introducing the atmosphere from the branch pipe 86 and discharging a part of the drying gas from the branch pipe 100 in this way suppresses an increase in the concentration of the volatile organic compound (VOC) in the circulation system of the drying gas. This is because. This can prevent accidents such as explosions. The volatile organic compound is contained in, for example, paint.

Next, the temperature control of the drying space 63 of the drying chamber 60 during the startup operation of the drying device 10 will be described.

FIG. 2 is a flowchart of the temperature control process of the drying space 63 of the drying chamber 60 during the startup operation of the drying device 10 of the embodiment.

When the combustion in the burner 30 starts, the control unit 90 determines whether or not the temperature of the drying gas has reached a predetermined temperature, based on the signal output from the temperature detection unit 88 (step S100).

Here, the predetermined temperature is, for example, a temperature that is 5% to 30% lower than the set temperature of the drying gas ejected from the ejection nozzle 71. That is, for example, when the set temperature of the drying gas ejected from the ejection nozzle 71 is 180° C., the predetermined temperature is in the range of 126 to 171° C.

A more preferable range of the predetermined temperature is, for example, a temperature that is 5 to 10% lower than the set temperature of the drying gas ejected from the ejection nozzle 71.

By setting the predetermined temperature to be 5% to 30% lower than the set temperature of the drying gas jetted from the jet nozzle 71, the temperature of the drying gas greatly changes beyond the set temperature in the subsequent temperature rising process. Can be prevented. That is, by setting the predetermined temperature within the above temperature range, the temperature can be adjusted to the set temperature more quickly in the subsequent temperature adjustment.

When it is determined in step S100 that the temperature of the drying gas detected by the temperature detection unit 88 has not reached the predetermined temperature (No in step S100), the control unit 90 increases the output of the burner 30 ( Step S101).

Specifically, the control unit 90 outputs an output signal for increasing the opening degree to the fuel flow rate adjusting valve 43, and outputs an output signal for increasing the rotation speed to the fan motor 52. That is, the control unit 90 increases the fuel flow rate and the air flow rate supplied to the burner 30. As a result, the output of the burner 30 increases and the temperature of the drying gas in the drying space 63 of the drying chamber 60 rises. Then, the temperature of the drying gas flowing through the return pipe 85 rises.

After performing the process of step S101, the process of step S100 is performed again.

When it is determined in step S100 that the temperature of the drying gas detected by the temperature detection unit 88 has reached the predetermined temperature (Yes in step S100), the control unit 90 outputs the temperature detection unit 72. Based on the signal, it is determined whether or not the temperature of the drying gas is the allowable set temperature (step S102).

Here, the allowable set temperature refers to a range of the set temperature ±2° C. of the drying gas ejected from the ejection nozzle 71. That is, the allowable set temperature is in the range of “set temperature of drying gas jetted from jet nozzle 71 −2° C.” or more and “set temperature of drying gas jetted from jet nozzle 71+2° C.” or less.

By maintaining the temperature of the drying gas at the allowable set temperature, the material to be dried W can be uniformly heated at an appropriate temperature without temperature unevenness. As a result, the amount of heat received by the article to be dried W received from the drying gas can be maintained constant, and the article to be dried W can be stably heated to a predetermined temperature.

When it is determined in step S102 that the temperature of the drying gas detected by the temperature detection unit 72 is the allowable set temperature (Yes in step S102), the control unit 90 maintains the current output of the burner 30. (Step S103).

Specifically, the control unit 90 maintains the current opening degree of the fuel flow rate adjusting valve 43 and maintains the current rotation speed of the fan motor 52. That is, the control unit 90 maintains each of the fuel flow rate and the air flow rate supplied to the burner 30 at the current flow rates. In this state, the temperature of the drying gas ejected from the ejection nozzle 71 of the drying chamber 60 is maintained at the allowable set temperature.

After the processing of step S103, the control unit 90 executes the processing of step S102.

When it is determined in step S102 that the temperature of the drying gas detected by the temperature detection unit 72 is not the allowable set temperature (No in step S102), the control unit 90 determines that the drying gas detected by the temperature detection unit 72 is used. It is determined whether the temperature of the gas is lower than the lower limit value of the allowable set temperature (step S104).

When it is determined in step S104 that the temperature of the drying gas detected by the temperature detection unit 72 is lower than the lower limit value of the allowable set temperature (Yes in step S104), the control unit 90 controls the output of the burner 30. Increase (step S105).

The control for increasing the output of the burner 30 is the same as the control in step S101. By increasing the output of the burner 30, the temperature of the drying gas ejected from the ejection nozzle 71 rises.

After performing the process of step S105, the process of step S102 is performed again.

When it is determined in step S104 that the temperature of the drying gas detected by the temperature detection unit 72 is not lower than the allowable set temperature, that is, higher than the upper limit of the allowable set temperature (No in step S104), The control unit 90 reduces the output of the burner 30 (step S106).

Specifically, the control unit 90 outputs an output signal for reducing the opening degree to the fuel flow rate adjusting valve 43, and outputs an output signal for reducing the rotation speed to the fan motor 52. That is, the control unit 90 reduces the fuel flow rate and the air flow rate supplied to the burner 30. As a result, the output of the burner 30 decreases and the temperature of the drying gas ejected from the ejection nozzle 71 decreases.

After performing the process of step S106, the process of step S102 is performed again.

Here, for example, in the processing in steps S102 and S103, when the temperature of the drying gas detected by the temperature detection unit 72 is maintained at the allowable set temperature for a predetermined time, the control unit 90 causes the drying. It may be determined that the startup of the device 10 is completed.

Then, after the start-up of the drying device 10 is completed, the article to be dried W is introduced into the drying device 10. That is, the transport device 62 in which the article to be dried W is arranged is driven, and the drying step of the article to be dried W is executed.

In the drying step, the article to be dried W is moved in the drying space 63 by the carrying device 62. At this time, the drying gas ejected from the ejection nozzle 71 collides with the article to be dried W and heats the article to be dried W to an appropriate temperature. Then, for example, the coating agent applied to the surface of the article to be dried W is dried.

In addition, also in the drying process step after the startup operation process, the processes of step S102 and thereafter are executed. Thereby, even when the temperature of the drying gas ejected from the ejection nozzle 71 deviates from the allowable set temperature during the drying process, the output of the burner 30 can be adjusted to the allowable set temperature.

In the temperature control of the drying device 10 described above, for example, when the control unit 90 determines that the signal related to the operation stop is input from the external switch such as the operation panel (not shown), the operation related to the drying process is ended. To do.

Specifically, for example, the control unit 90 closes the shutoff valves 44 and 45 to stop the combustion in the burner 30.

As described above, in the drying device 10 according to the embodiment, during the startup operation of the drying device 10, the temperature of the drying gas flowing through the return pipe 85, in other words, the temperature close to the average temperature of the drying space 63 of the drying chamber 60. Alternatively, the output of the burner 30 is adjusted based on the temperature of the drying gas ejected from the ejection nozzle 71.

As described above, in the drying device 10, in the start-up operation of the drying device 10, until the temperature of the drying gas flowing through the return pipe 85 reaches the predetermined temperature from the start of operation, the output of the burner 30 is adjusted through the return pipe 85. It is performed based on the temperature of the flowing drying gas. Then, after the temperature of the drying gas flowing through the return pipe 85 reaches the predetermined temperature, the reference temperature for adjusting the output of the burner 30 is switched to the temperature of the drying gas ejected from the ejection nozzle 71.

The output of the burner 30 is adjusted based on the temperature of the drying gas in the drying space 63 until the temperature of the drying gas flowing through the return pipe 85 reaches a predetermined temperature from the start of the operation. The temperature can be adjusted to a temperature close to the set temperature (for example, 5 to 30% lower than the set temperature of the drying gas jetted from the jet nozzle 71).

Thereby, the structure having a large heat capacity in the drying device 10 can be sufficiently heated.

Further, as described above, the temperature of the drying gas in the drying space 63 of the drying chamber 60 is close to the set temperature. Therefore, even if the output of the burner 30 is adjusted based on the temperature of the drying gas ejected from the ejection nozzle 71, the drying gas having an appropriate temperature can be made to collide with the article W to be dried.

As a result, the amount of heat received by the drying target W from the drying gas can be maintained constant, the temperature of the drying target W can be stably raised to a predetermined temperature, and optimal drying can be performed.

In addition, although the drying chamber 60 extended linearly is illustrated here, it is not limited to this configuration. For example, the drying chamber may have a configuration in which an object to be dried is placed on a turntable and the object to be dried is rotated and dried.

While some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

10... Drying device, 20... Combustion chamber, 20a... One end, 20b... Other end, 21... Filter, 30... Burner, 31, 61... Casing, 32... Flame stabilizer, 40... Fuel supply system, 41... Fuel supply source , 42... Fuel supply pipe, 43... Fuel flow rate adjusting valve, 44, 45... Cutoff valve, 46... Fuel flow meter, 50... Air supply system, 51... Intake fan, 52, 82... Fan motor, 53, 83... Fan Tachometer, 60... Drying chamber, 62... Conveying device, 63... Drying space, 70... Duct, 71... Jet nozzle, 72, 88... Temperature detecting part, 80... Introducing pipe, 80a... Branching part, 81... Circulation fan , 85... Return pipe, 86, 100... Branch pipe, 87, 101... Flow rate adjusting unit, 90... Control unit, W... Dried object.

Claims (3)

A combustion chamber with a burner,
A drying chamber for drying the material to be dried by the drying gas discharged from the combustion chamber,
A duct which is disposed in the drying chamber and into which the drying gas discharged from the combustion chamber is introduced,
An ejection nozzle that is disposed in the duct and ejects a drying gas toward an object to be dried,
A return pipe that guides the drying gas in the drying chamber, in which the material to be dried is dried, into the combustion chamber,
A return gas temperature detection unit for detecting the temperature of the drying gas flowing in the return pipe,
An ejection gas temperature detection unit that detects the temperature of the drying gas ejected from the ejection nozzle,
From the start of operation until the temperature of the drying gas flowing in the return pipe reaches a predetermined temperature, the output of the burner is adjusted based on the detection signal detected by the return gas temperature detection unit, and the inside of the return pipe is adjusted. And a controller that adjusts the output of the burner based on a detection signal detected by the jet gas temperature detector after the temperature of the flowing drying gas reaches the predetermined temperature. apparatus. The drying apparatus according to claim 1, wherein the controller controls the flow rates of fuel and air supplied to the burner when adjusting the output of the burner. The drying device according to claim 1 or 2, wherein the predetermined temperature is 5 to 30% lower than the set temperature of the drying gas ejected from the ejection nozzle.

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