JP2022161494A - Drying facility, and method of controlling voc concentration in drying facility - Google Patents

Abstract

To provide a drying facility capable of keeping a VOC concentration at a prescribed concentration without increasing its size and without making it complicated, and a method of controlling the VOC concentration.SOLUTION: A drying facility 10 according to an embodiment of the present invention, comprises: a combustion air introduction pipe 100 that comprises a blower 101 and a damper 102 and introduces air into a combustion device 50; a fuel introduction pipe 110 that comprises a flow control valve 111 and introduces fuel into the combustion device 50; a drying gas introduction pipe 130 that introduces drying gas into a drying furnace 20 from the combustion device 50; an exhaust pipe 140 that comprises an exhaust fan 142 and exhausts exhaust gas from the drying furnace 20; a VOC concentration detector 143 that detects the concentration of VOC contained in exhaust gas present in the exhaust pipe 140; a gas temperature detector 132 that detects the temperature of the drying gas; and a controller that controls the exhaust fan 142 and the blower 101 according to the signal detected by the VOC concentration detector 143 and controls the damper 102 and the flow control valve 111 according to the signal detected by the gas temperature detector 132.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to drying equipment and VOC concentration control methods for drying equipment.

As conventional drying equipment, a drying furnace that dries the material to be dried using a drying gas generated by a heat source such as a combustion device, and a cooling furnace that cools the material dried in the drying furnace. There are facilities. In such drying equipment, a circulation-type drying furnace is widely used as the drying furnace, in which part of the drying gas used to dry the material to be dried is returned to the heat source.

In such conventional drying equipment, a drying gas, which is hot air, is introduced into the drying furnace, and a cooling gas, which is cold air, is introduced into the cooling furnace. Therefore, in conventional drying equipment that uses hot air for drying gas and cold air for cooling gas, equipment equipped with a heat pump is being considered in order to improve energy efficiency.

In a drying facility equipped with a heat pump, for example, air heated by obtaining heat in a condenser-side heat exchanger (heating-side heat exchanger) of the heat pump is introduced into a combustion device. The air introduced into the combustion device is used, for example, as dilution air for adjusting the temperature of the combustion gas and as cooling air for cooling the combustion device. A mixed gas of the combustion gas and the dilution air is introduced into the drying furnace as a drying gas. The combustion device also includes a supply line for combustion air used for combustion with the fuel.

On the other hand, in a drying facility equipped with a heat pump, the air cooled by losing heat in the evaporator of the heat pump is introduced into the cooling furnace as cooling air.

In a drying facility equipped with a heat pump, although the flow rate varies depending on the outside air temperature, the coefficient of performance (COP) of the heat pump is maintained at the maximum value while heating and cooling a predetermined flow rate of air.

In the drying furnace of such drying equipment, when the coating film of the coated material to be dried is dried, volatile organic compounds (hereinafter referred to as VOC) contained in the coating film evaporate. Explosion may occur when the VOC concentration in the drying furnace reaches a predetermined range. Therefore, it is necessary to maintain the VOC concentration in the drying furnace at a predetermined value (eg, 1/4 of the lower explosion limit) or less.

If the VOC concentration exceeds a predetermined value in the drying oven, it is necessary to reduce the VOC concentration. In such a case, the drying furnace of the conventional drying equipment employs a system in which the VOC contained in the circulating drying gas is recovered and removed, and the drying gas is circulated to the drying furnace. In the conventional drying equipment, the VOC removal circulation system adjusts the VOC concentration in the drying furnace to a predetermined value or less.

JP 2010-51932 A

However, equipping the drying equipment with the VOC removal circulation system as described above causes the drying equipment to become larger and more complicated.

In addition, adding a VOC removal circulation system as described above to an existing drying facility that does not have a function to remove VOCs requires large-scale expansion work, and the drying facility becomes larger and more complicated. invite.

The problem to be solved by the present invention is to provide a drying facility and a method for controlling the VOC concentration of the drying facility, which can maintain the VOC concentration in the drying furnace at a predetermined concentration without increasing the size and complexity of the drying furnace. be.

The drying equipment of the embodiment includes a combustion device, an air supplier and an air flow rate adjustment unit, a combustion air introduction pipe for introducing combustion air into the combustion device, and a fuel flow rate adjustment valve. A heat pump equipped with a fuel introduction pipe for introducing fuel, a dilution air introduction pipe for introducing dilution air into the combustion device, and a heating heat exchanger for heating the dilution air flowing through the dilution air introduction pipe. , a branch pipe branched from the combustion air introduction pipe between the air supply device and the air flow rate adjustment unit and connected to the dilution air introduction pipe, a drying device for drying the material to be dried, and the combustion A drying gas introduction pipe that introduces a mixed gas containing combustion gas and dilution air generated in the device into the drying device as drying gas, and an exhaust pipe that includes an exhaust blower and exhausts the drying gas from the drying device. and a drying gas circulation pipe that introduces the drying gas from the drying device into the dilution air introduction pipe and circulates it to the combustion device, and the drying gas in the drying device. A VOC concentration detector that detects the concentration of organic compounds, a gas temperature detector that detects the temperature of the drying gas related to the drying gas in the drying device, and based on detection signals from the VOC concentration detector, a control unit that controls the exhaust blower and the air supply device, and controls the air flow rate adjustment unit and the fuel flow rate adjustment valve based on a detection signal from the gas temperature detector;

According to the drying equipment and the VOC concentration control method of the drying equipment of the present invention, the VOC concentration in the drying furnace can be maintained at a predetermined concentration without causing an increase in size or complexity.

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed typically the outline|summary of the drying equipment of 1st Embodiment. FIG. 4 is a block diagram showing the configuration of a control unit that performs control for maintaining the VOC concentration in the VOC concentration detector at the VOC concentration threshold in the drying equipment of the first embodiment; 4 is a flow chart for explaining the operation of the drying equipment of the first embodiment for maintaining the VOC concentration in the exhaust gas at the VOC concentration threshold. 4 is a flow chart for explaining the operation of adjusting the temperature of the drying gas among the operations for maintaining the VOC concentration in the exhaust gas at the VOC concentration threshold value in the drying equipment of the first embodiment. It is the figure which showed typically the outline|summary of the drying equipment of 2nd Embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram schematically showing the outline of the drying equipment 10 of the first embodiment.

As shown in FIG. 1 , the drying equipment 10 includes a drying furnace 20 and a cooling furnace 30 . The drying furnace 20 functions as a drying device, and the cooling furnace 30 functions as a cooling device.

To the drying furnace 20, for example, a work W whose surface is coated with paint in a coating section is conveyed. Then, in the drying furnace 20, the hot air of the drying gas is applied to the work W, which is the object to be dried, to dry the paint applied on the surface of the work W, for example. During the drying process in the drying furnace 20, VOCs contained in the paint evaporate.

The work W dried in the drying furnace 20 is transferred to the cooling furnace 30 . Then, in the cooling furnace 30, cold air for cooling is applied to the work W dried in the drying furnace 20 to cool the work W, for example.

The work W is transported in the drying furnace 20 and the cooling furnace 30 in a state of being suspended by a wire or the like, for example.

In addition, although not shown, the drying furnace 20 is provided with, for example, an ejection nozzle for ejecting a drying gas onto the workpiece W being conveyed. The temperature of the drying gas jetted to the work W is, for example, 60 to 200.degree. Note that the temperature of the drying gas is appropriately set according to the specifications of the work W. FIG.

In addition, although not shown, the cooling furnace 30 is provided with, for example, a jet nozzle for jetting cooling air to the workpiece W being conveyed. The temperature of the cooling air jetted to the work W is, for example, 15 to 30.degree. Note that the temperature of the cooling air is appropriately set according to the specifications of the workpiece W.

Thus, in the drying equipment 10, it is necessary to generate drying gas (hot air) to be introduced into the drying furnace 20 and cooling air (cold air) to be introduced into the cooling furnace 30. FIG. Therefore, the drying equipment 10 is provided with a heat pump 40 capable of exhibiting both heat radiation and heat absorption functions. By providing the heat pump 40, the energy efficiency of the drying equipment 10 can be improved.

As shown in FIG. 1, the heat pump 40 includes a refrigerant channel 41 through which a refrigerant as a heat medium flows. The coolant channel 41 constitutes an annular circulation channel. A condenser 42 (heat radiation portion), an evaporator 43 (heat absorption portion), a compressor 44 and an expansion valve 45 are interposed in the refrigerant flow path 41 .

The compressor 44 is arranged upstream of the condenser 42 . In other words, the compressor 44 is arranged upstream of the condenser 42 and between the condenser 42 and the evaporator 43 . The compressor 44 compresses the refrigerant flowing through the refrigerant flow path 41 and sends it to the condenser 42 .

The expansion valve 45 is arranged upstream of the evaporator 43 . In other words, the expansion valve 45 is arranged upstream of the evaporator 43 and between the condenser 42 and the evaporator 43 . The expansion valve 45 has a function of adjusting the refrigerant flow path 41 from a fully open state to a fully closed state. Refrigerant is supplied to the evaporator 43 when the expansion valve 45 is not fully closed.

In the heat pump 40 configured as described above, the expansion valve 45 is closed and the compressor 44 is driven to send the refrigerant to the condenser 42 . At this time, most of the refrigerant flow is stopped by the expansion valve 45 . This compresses the refrigerant and raises the temperature of the refrigerant near the condenser 42 .

On the other hand, as the refrigerant near the condenser 42 is compressed, the refrigerant near the evaporator 43 expands and becomes low temperature.

A dilution air introduction pipe 60 for introducing dilution air into the combustion device 50 is connected to the condenser 42 . In other words, in the condenser 42 , heat exchange takes place between the refrigerant flowing through the refrigerant channel 41 and the air flowing through the dilution air introduction pipe 60 . As described above, when the compressor 44 is driven with the expansion valve 45 closed, the temperature of the refrigerant near the condenser 42 rises, and thus the dilution air is heated. Note that the condenser 42 functions as a heat exchanger for heating.

A part of an air cooling mechanism 70 that cools the air that introduces the cooling air into the cooling furnace 30 is piped to the evaporator 43 . Specifically, a refrigerant circulation pipe 71 for circulating the refrigerant in the air cooling mechanism 70 is arranged. In other words, in the evaporator 43 , heat exchange takes place between the refrigerant flowing through the refrigerant flow path 41 and the refrigerant flowing through the refrigerant circulation pipe 71 .

As described above, when the compressor 44 is driven with the expansion valve 45 closed, the temperature of the refrigerant near the evaporator 43 is lowered, so the refrigerant flowing through the refrigerant circulation pipe 71 is cooled. Note that the evaporator 43 functions as a refrigerant cooling heat exchanger that cools the refrigerant flowing through the refrigerant circulation pipe 71 . Here, for example, water is used as the coolant flowing through the coolant circulation pipe 71 .

The air cooling mechanism 70 also includes an air cooling heat exchanger 72 that cools the cooling air flowing through the cooling air introduction pipe 80 with the refrigerant flowing through the refrigerant circulation pipe 71 . The air cooling mechanism 70 also includes a circulation pump 73 that circulates the coolant. The circulation pump 73 is interposed in the refrigerant circulation pipe 71 .

As shown in FIG. 1, the refrigerant circulation pipe 71 through which the refrigerant passes through the air cooling heat exchanger 72 may be provided with a refrigerant heating heat exchanger 74 for heating the refrigerant flowing through the refrigerant circulation pipe 71. good. For example, a part of a branch exhaust pipe 145 branched from an exhaust pipe 140 of the drying furnace 20 (to be described later) is arranged to pass through the refrigerant heating heat exchanger 74 .

The branch exhaust pipe 145 is provided with a flow rate control valve 146 for adjusting the flow rate of exhaust gas flowing through the branch exhaust pipe 145 .

When the temperature of the refrigerant that has passed through the air-cooling heat exchanger 72 is lower than a predetermined temperature, the refrigerant flowing through the refrigerant circulation pipe 71 passes through the branch exhaust pipe 145 in the refrigerant-heating heat exchanger 74. heated by Thereby, the refrigerant is circulated to the evaporator 43 at a predetermined temperature, and the maximum cooling-side coefficient of performance (COP) is obtained in the heat pump 40 .

The cooling air introduction pipe 80 passes through the air cooling heat exchanger 72 and is connected to the cooling furnace 30 . In the air cooling heat exchanger 72 , heat is exchanged between the refrigerant flowing through the refrigerant circulation pipe 71 and the air flowing through the cooling air introduction pipe 80 . The air flowing through the cooling air introduction pipe 80 is cooled by the low-temperature refrigerant flowing through the refrigerant circulation pipe 71 . This cooled air is introduced into the cooling furnace 30 as cooling air.

A fan 81 is interposed in the cooling air introduction pipe 80 to take in air from the outside air into the cooling air introduction pipe 80 and introduce the cooling air into the cooling furnace 30 . Note that the fan 81 functions as a blower. As an air blower, for example, a blower may be used.

Also, the cooling air that has cooled the work W in the cooling furnace 30 is exhausted through the cooling air discharge pipe 90 . An exhaust fan 91 for discharging the cooling air from the cooling furnace 30 to the atmosphere is interposed in the cooling air discharge pipe 90 .

Next, the configuration for introducing the drying gas (hot air) into the drying furnace 20 will be described.

As shown in FIG. 1, the drying equipment 10 includes a combustion device 50, a combustion air introduction pipe 100, a fuel introduction pipe 110, a branch pipe 120, a dilution air introduction pipe 60, and a drying gas introduction pipe 130. , an exhaust pipe 140 , and a drying gas circulation pipe 150 . The drying equipment 10 also includes a control unit 160 that controls the drying equipment 10 .

The combustion device 50 comprises a combustion liner 51 for combusting fuel and air, and a casing 52 containing the combustion liner 51 . A gap 53 is provided between combustion liner 51 and casing 52 .

Combustion air introduction pipe 100 introduces combustion air into combustion device 50 . Specifically, the combustion air introduction pipe 100 is connected to the combustion liner 51 and introduces air into the combustion liner 51 . The combustion air introduction pipe 100 is provided with a blower 101 that introduces outside air into the combustion air introduction pipe 100 and guides it to the combustion device 50 . Note that the blower 101 functions as an air supplier. A fan, for example, may be used as the air supply.

A damper 102 is interposed in the combustion air introduction pipe 100 . The damper 102 adjusts the flow rate of combustion air introduced into the combustion liner 51 . The damper 102 functions as an air flow adjuster. The air flow rate adjusting section may be composed of, for example, a valve.

A part of the combustion air introduction pipe 100 is configured to exchange heat with the drying gas flowing through the exhaust pipe 140, as shown in FIG. The drying gas flowing through the exhaust pipe 140 is the drying gas that has dried the work W in the drying furnace 20 and is exhausted to the outside. Hereinafter, the drying gas flowing through the exhaust pipe 140 is referred to as exhaust gas.

The combustion air introduction pipe 100 is arranged, for example, so as to pass through a heat exchanger 141 provided in an exhaust pipe 140 . The air flowing through the combustion air introduction pipe 100 is heated by the exhaust gas via the heat exchanger 141 .

Fuel introduction pipe 110 introduces fuel into combustion device 50 . Specifically, fuel inlet tube 110 is coupled to combustion liner 51 and introduces fuel into combustion liner 51 from a fuel supply source (not shown). Although the fuel is not particularly limited, for example, a hydrocarbon fuel or the like is used.

A flow control valve 111 for adjusting the flow rate of the fuel introduced into the combustion liner 51 is interposed in the fuel introduction pipe 110 . A fuel flow meter 112 for measuring the flow rate of the fuel introduced into the combustion liner 51 is interposed in the fuel introduction pipe 110 . The flow control valve 111 is configured by a valve or the like. In addition, the flow control valve 111 functions as a fuel flow control valve.

The branch pipe 120 branches from the combustion air introduction pipe 100 between the blower 101 and the damper 102 and is connected to the dilution air introduction pipe 60 . Specifically, the branch pipe 120 branches from the combustion air introduction pipe 100 downstream of the heat exchanger 141 and upstream of the damper 102 .

The branch pipe 120 is connected to the dilution air introduction pipe 60 between the heat pump 40 and the combustion device 50 . Also, the branch pipe 120 is provided with a damper 121 that adjusts the flow rate of the air introduced to the dilution air introduction pipe 60 . A valve may be provided instead of the damper 121 .

The air flowing through the branch pipe 120 functions as dilution air. The air flowing through the branch pipe 120 is introduced into the combustion device 50 together with the dilution air flowing through the dilution air introduction pipe 60 .

The dilution air introduction pipe 60 introduces the dilution air into the combustion device 50 as described above. Specifically, the dilution air introduction pipe 60 introduces the dilution air into the gap 53 between the combustion liner 51 and the casing 52, for example.

The dilution air introduced into the gap 53 flows downstream through the gap 53 , mixes with the combustion gas discharged from the combustion liner 51 , and flows into the drying gas introduction pipe 130 . For example, the dilution air flows into the combustion liner 51 through dilution holes formed in the combustion liner 51 and is discharged from the combustion liner 51 together with the combustion gas.

In this manner, the dilution air mixes with the combustion gas discharged from the combustion liner 51 and the combustion gas within the combustion liner 51 to dilute the combustion gas and adjust the temperature of the combustion gas to a predetermined temperature. This reduces the temperature of the combustion gases. Here, the predetermined temperature is the temperature required for the drying oven 20 .

Further, the dilution air flowing downstream through the gap 53 also functions as a cooling medium for cooling the combustion liner 51 and the casing 52 .

The air flowing through the dilution air introduction pipe 60 is heated by the refrigerant flowing through the refrigerant flow path 41 in the condenser 42 that functions as a heating heat exchanger. The flow rate of the air flowing through the dilution air introduction pipe 60 is adjusted to a constant flow rate.

The dilution air introduction pipe 60 is provided with a fan 61 that introduces outside air into the dilution air introduction pipe 60 and guides it to the combustion device 50 . The fan 61 is housed in the heat pump 40, for example. Note that the fan 61 functions as a blower. As an air blower, for example, a blower may be used.

The drying gas introduction pipe 130 feeds a mixed gas containing combustion gas generated by combustion of fuel and combustion air in the combustion liner 51 and dilution air introduced from the dilution air introduction pipe 60 into a drying gas. , and is introduced from the combustion device 50 into the drying furnace 20 . That is, the drying gas introduction pipe 130 connects the combustion device 50 and the drying furnace 20 . The mixed gas also includes the circulated drying gas introduced into the dilution air introduction pipe 60 via the drying gas circulation pipe 150 .

The drying gas introduced from the combustion device 50 into the drying furnace 20 is introduced into the drying gas introduction pipe 130, and the drying gas used to dry the work W is circulated from the drying furnace 20 to the combustion device 50. A fan 131 is provided for circulation through a pipe 150 . Note that the fan 131 functions as a blower. As an air blower, for example, a blower may be used.

For example, the drying gas introduction pipe 130 is provided with a gas temperature detector 132 that detects the temperature of the drying gas flowing through the drying gas introduction pipe 130 . In this case, the gas temperature detector 132 is provided in the drying gas introduction pipe 130 . The gas temperature detector 132 is composed of, for example, a thermocouple.

Here, the gas temperature detector 132 detects the temperature of the drying gas in the drying furnace 20 . The drying gas related to the drying gas in the drying furnace 20 is the drying gas that can be regarded as the drying gas in the drying furnace 20 .

As the drying gas related to the drying gas in the drying furnace 20, in addition to the drying gas in the drying furnace 20, the drying gas in the drying gas introduction pipe 130 and the drying gas in the drying gas circulation pipe 150 gas.

In other words, the gas temperature detector 132 is arranged to detect the temperature of the drying gas flowing through the drying gas introduction pipe 130, and also to detect the temperature of the drying gas in the drying furnace 20. It may be arranged in the drying furnace 20 or may be arranged in the drying gas circulation pipe 150 so as to detect the temperature of the drying gas flowing through the drying gas circulation pipe 150 .

Also, the gas temperature detector 132 may be provided to detect the temperature of the drying gas in at least one of the drying gas introduction pipe 130 , the drying furnace 20 and the drying gas circulation pipe 150 . When the gas temperature detectors 132 are provided at a plurality of these locations, for example, each control is executed based on the temperature at which the difference from the gas temperature threshold, which will be described later, becomes the largest.

The drying gas circulation pipe 150 introduces the drying gas from the drying furnace 20 to the dilution air introduction pipe 60 . As a result, the drying gas introduced into the dilution air introduction pipe 60 through the drying gas circulation pipe 150 is circulated to the combustion device 50 .

Here, the drying gas circulated to the combustion device 50 is again introduced into the drying furnace 20 through the drying gas introduction pipe 130 as the drying gas. The drying gas flowing through the drying gas circulation pipe 150 is the drying gas used to dry the work W in the drying furnace 20 .

The drying gas circulation pipe 150 connects the drying furnace 20 and the dilution air introduction pipe 60 between the heat pump 40 and the combustion device 50 .

The drying gas circulation pipe 150 is connected to the dilution air introduction pipe 60 on the heat pump 40 side of the position where the branch pipe 120 is connected to the dilution air introduction pipe 60 , for example. The connection portion of the drying gas circulation pipe 150 with the dilution air introduction pipe 60 may be closer to the combustion device 50 than the connection portion of the branch pipe 120 with the dilution air introduction pipe 60 .

The exhaust pipe 140 exhausts exhaust gas from the drying furnace 20 into the atmosphere. One end of the exhaust pipe 140 is connected to the drying furnace 20, and the other end of the exhaust pipe 140 is open to the atmosphere, for example.

The exhaust pipe 140 is provided with an exhaust fan 142 for sucking the exhaust gas from the drying furnace 20 and discharging it to the atmosphere. Note that the exhaust fan 142 functions as an exhaust blower. A blower, for example, may be used as an exhaust fan.

Further, the exhaust pipe 140 is provided with the heat exchanger 141 as described above. The air flowing through the combustion air introduction pipe 100 is heated by the exhaust gas flowing through the exhaust pipe 140 via the heat exchanger 141 .

Furthermore, the exhaust pipe 140 is provided with a VOC concentration detector 143 that detects the VOC concentration contained in the exhaust gas flowing through the exhaust pipe 140 . The VOC concentration detector 143 is provided in the exhaust pipe 140 between the heat exchanger 141 and the drying furnace 20, for example.

Here, the VOC concentration detector 143 detects the VOC concentration contained in the drying gas related to the drying gas in the drying furnace 20 . The drying gas related to the drying gas in the drying furnace 20 is the drying gas that can be regarded as the drying gas in the drying furnace 20 .

Examples of the drying gas related to the drying gas in the drying furnace 20 include the drying gas in the exhaust pipe 140 and the drying gas in the drying gas circulation pipe 150 in addition to the drying gas in the drying furnace 20. be done.

That is, the VOC concentration detector 143 is arranged to detect the VOC concentration contained in the exhaust gas flowing through the exhaust pipe 140 described above, and also arranged to detect the VOC concentration contained in the drying gas in the drying furnace 20. Alternatively, it may be arranged in the drying gas circulation pipe 150 so as to detect the VOC concentration contained in the drying gas flowing through the drying gas circulation pipe 150 .

Also, the VOC concentration detector 143 is provided to detect the VOC concentration contained in the drying gas (or exhaust gas) in at least one of the exhaust pipe 140, the drying furnace 20, and the drying gas circulation pipe 150. may If the VOC concentration detectors 143 are provided at a plurality of these locations, each control is executed based on, for example, the VOC concentration at which the difference from the VOC concentration threshold, which will be described later, is the largest.

The VOC concentration detector 143 is composed of, for example, a detector using a measurement method such as the FID method (flame ionization method), catalytic oxidation-nondispersive infrared absorption method, or the like. Here, VOC is a generic term for organic compounds that are volatile and gaseous in the atmosphere, and include substances such as toluene, xylene, and ethyl acetate. Note that the VOC concentration detector 143 may be composed of, for example, a detector that detects a predetermined organic compound contained in VOC. In this case, a VOC concentration threshold, which will be described later, is appropriately set based on, for example, the permissible limit concentration of a predetermined organic compound.

The controller 160 controls, for example, the exhaust fan 142 and the blower 101 based on the signal detected by the VOC concentration detector 143 . Also, the control unit 160 controls, for example, the dampers 102 and 121 and the flow control valve 111 based on the signal detected by the gas temperature detector 132 .

Here, FIG. 2 is a block diagram showing the configuration of the control unit 160 that executes control for maintaining the VOC concentration in the VOC concentration detector 143 at the VOC concentration threshold in the drying equipment 10 of the first embodiment. be.

As described above, the VOC concentration detector 143 can detect the drying gas (including the exhaust gas) inside the exhaust pipe 140, inside the drying furnace 20, inside the drying gas circulation pipe 150, and the like. Here, an example is shown in which the detection location of the VOC concentration detector 143 is inside the exhaust pipe 140 .

As shown in FIG. 2 , the control section 160 includes an input section 170 , a computing section 180 , a storage section 190 and an output section 171 .

The input unit 170 inputs detection signals from various detection units and flowmeters. Specifically, the input unit 170 inputs detection signals from, for example, the VOC concentration detector 143, the gas temperature detector 132, the fuel flow meter 112, and the like.

The storage unit 190 is composed of a storage medium such as a read only memory (ROM) and a random access memory (RAM). The storage unit 190 includes a threshold storage unit 191 and a flow correlation storage unit 192 .

The threshold storage unit 191 provides reference values for determination by each determination unit and each setting unit of the calculation unit 180 . The threshold storage unit 191 stores, for example, a VOC concentration threshold that serves as a reference value for VOC concentration adjustment operation for maintaining the VOC concentration at a predetermined concentration. The VOC concentration threshold is set to 1/4 of the lower explosive limit of VOC gas. The lower explosion limit is the lowest concentration (minimum concentration) of the concentrations within the explosion range of VOC gas.

By setting the VOC concentration threshold within the above range, the drying equipment 10 can be safely operated even when the detected VOC concentration fluctuates. Here, the VOC concentration threshold is not limited to the range described above. The VOC concentration threshold can be appropriately set based on, for example, the specifications of the drying furnace 20, the operating environment of the drying furnace 20, and the like.

In the VOC concentration adjustment operation, control is performed so that the detected VOC concentration maintains the VOC concentration threshold value. If the detected VOC concentration is higher than the VOC concentration threshold or lower than the VOC concentration threshold, for example, the flow rate of the exhaust gas and the flow rate of the combustion air and dilution air introduced into the combustion device 50 are adjusted.

The threshold storage unit 191 also stores, for example, a gas temperature threshold for the temperature of the drying gas introduced into the drying furnace 20 . The gas temperature threshold can be arbitrarily set according to, for example, the type of work W to be dried.

Note that when the gas temperature detector 132 is arranged to detect the temperature of the drying gas in the drying furnace 20 , the threshold storage unit 191 stores the gas temperature threshold value of the temperature of the drying gas in the drying furnace 20 . is stored. Further, when the gas temperature detector 132 is arranged to detect the temperature of the drying gas flowing through the drying gas circulation pipe 150, the threshold storage unit 191 stores the gas temperature of the circulated drying gas. Stores the threshold.

When the temperature of the drying gas introduced into the drying furnace 20 is higher than the gas temperature threshold or lower than the gas temperature threshold, for example, the combustion air, fuel, and dilution air introduced into the combustion device 50 Adjust the flow rate.

The flow correlation storage unit 192 provides reference values for determination by the VOC concentration determination unit 181 and the temperature determination unit 182 of the calculation unit 180 .

The flow correlation storage unit 192 stores, for example, an exhaust gas flow rate/VOC concentration correlation table for setting the flow rate of the exhaust gas based on the difference between the VOC concentration in the exhaust gas detected by the VOC concentration detector 143 and the VOC concentration threshold. is stored.

Note that the flow rate of exhaust gas to be exhausted is determined by, for example, the number of rotations of the exhaust fan 142 . Therefore, specifically, the exhaust gas flow rate/VOC concentration correlation table is a correlation that determines the rotation speed of the exhaust fan 142 based on the difference between the VOC concentration in the exhaust gas detected by the VOC concentration detector 143 and the VOC concentration threshold value. Consists of data.

Further, the flow rate correlation storage unit 192 stores, for example, an exhaust gas flow rate/air flow rate correlation table for introducing air having the same flow rate as the flow rate of the exhaust gas discharged by the exhaust fan 142 from the blower 101 to the combustion air introduction pipe 100. is doing.

Specifically, the exhaust gas flow rate/air flow rate correlation table is composed of correlation data that defines the number of revolutions of the blower 101 for discharging air at the same flow rate as the exhaust gas flow rate. For example, the exhaust gas flow rate/air flow rate correlation table is composed of correlation data that defines the correspondence between the rotation speed of the exhaust fan 142 and the rotation speed of the blower 101 .

Further, the flow rate correlation storage unit 192 stores, for example, a fuel flow rate/air flow rate correlation table for setting the flow rate of combustion air based on the fuel flow rate.

In the combustion device 50, the air flow rate is adjusted to a predetermined ratio with respect to the fuel flow rate. In other words, in the combustion device 50, the air flow rate is adjusted to a predetermined air-fuel ratio or equivalence ratio with respect to the fuel flow rate. The fuel flow rate/air flow rate correlation table is composed of, for example, correlation data that defines the air flow rate corresponding to the fuel flow rate.

The air flow rate is set, for example, based on data regarding the opening degrees of the dampers 102 and 121 set according to the rotational speed of the blower 101 .

Further, the flow correlation storage unit 192 stores, for example, a fuel flow rate/gas temperature correlation table for setting the fuel flow rate based on the difference between the temperature of the drying gas detected by the gas temperature detector 132 and the gas temperature threshold. Stored.

The fuel flow rate/gas temperature correlation table is composed of correlation data defining the fuel flow rate in proportion to the difference (temperature difference) between the detected drying gas temperature and the gas temperature threshold. Specifically, the fuel flow rate/gas temperature correlation table specifies, for example, when the temperature of the drying gas detected by the gas temperature detector 132 is lower than the gas temperature threshold, the fuel flow rate is increased in proportion to the temperature difference. It has established. Further, the fuel flow rate/gas temperature correlation table defines the fuel flow rate to be decreased in proportion to the temperature difference when the temperature of the drying gas detected by the gas temperature detector 132 is higher than the gas temperature threshold, for example. .

The arithmetic unit 180 executes various kinds of arithmetic processing using, for example, programs and data stored in the storage unit 190 . The computing section 180 includes a VOC concentration determination section 181 and a temperature determination section 182 .

Based on the VOC concentration threshold stored in the threshold storage unit 191 and the detection signal from the VOC concentration detector 143, the VOC concentration determination unit 181 determines whether the VOC concentration in the exhaust gas is equal to the VOC concentration threshold. Determine whether the VOC concentration is higher than the VOC concentration threshold or lower than the VOC concentration threshold.

Then, if it is determined that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold or if it is determined that the VOC concentration in the exhaust gas is lower than the VOC concentration threshold, the VOC concentration determination unit 181 determines the VOC concentration in the exhaust gas and the VOC concentration A signal for controlling the exhaust fan 142 is output to the output section 171 based on the difference from the concentration threshold and the exhaust gas flow rate/VOC concentration correlation table stored in the flow rate correlation storage section 192 .

Further, when it is determined that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold value or when it is determined that the VOC concentration in the exhaust gas is lower than the VOC concentration threshold value, the VOC concentration determination unit 181 determines the flow rate of the exhaust gas (for example, the exhaust gas A signal for controlling the blower 101 is output to the output unit 171 based on the rotation speed of the fan 142) and the exhaust gas flow rate/air flow rate correlation table.

The temperature determination unit 182 determines, for example, whether the temperature of the drying gas is the gas temperature threshold based on the gas temperature threshold stored in the threshold storage unit 191 and the detection signal from the gas temperature detector 132. . Also, the temperature determination unit 182 determines, for example, whether the temperature of the drying gas is higher or lower than the gas temperature threshold.

Then, for example, when the VOC concentration determination unit 181 determines that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold value, and determines that the temperature of the drying gas is higher or lower than the gas temperature threshold value, Based on the difference between the detected drying gas temperature and the gas temperature threshold, and the fuel flow/gas temperature correlation table and the fuel flow/air flow correlation table stored in the flow correlation storage unit 192, the temperature determination unit 182 determines: It controls the dampers 102 and 121 and the flow control valve 111 .

For example, when determining that the temperature of the drying gas is higher than the gas temperature threshold, the temperature determining unit 182 stores the difference between the detected drying gas temperature and the gas temperature threshold and the fuel flow rate/gas temperature correlation table. A signal for throttling the flow rate control valve 111 is output to the output section 171 based on the data, and a signal for throttling the damper 102 is output to the output section 171 based on the fuel flow rate and the fuel flow rate/air flow rate correlation table.

At this time, the temperature determination unit 182 may output a signal for adjusting the opening of the damper 121 to the output unit 171 .

When determining that the exhaust gas temperature is lower than the exhaust gas temperature threshold, the temperature determining unit 182 determines the difference between the detected temperature of the drying gas and the gas temperature threshold, and based on the fuel flow rate/gas temperature correlation table. A signal for opening the flow rate control valve 111 is output to the output section 171, and a signal for opening the damper 102 is output to the output section 171 based on the fuel flow rate and the fuel flow rate/air flow rate correlation table.

At this time, the temperature determination unit 182 may output a signal for adjusting the opening of the damper 121 to the output unit 171 .

The output unit 171 outputs the control signal from the VOC concentration determination unit 181 to the blower 101 and the exhaust fan 142, for example. Also, the output unit 171 outputs the control signal from the temperature determination unit 182 to the flow control valve 111 and the dampers 102 and 121, for example.

Here, the processing executed by the control unit 160 described above is implemented by, for example, a computer device.

Here, the operation of the drying equipment 10 will be described.

First, the operation of the drying furnace 20 will be described.

As shown in FIG. 1, the dilution air drawn from the atmosphere into the dilution air introduction pipe 60 by the fan 61 passes through the condenser 42 and is heated. The flow rate of the dilution air introduced into the dilution air introduction pipe 60 and the temperature of the dilution air after passing through the condenser 42 are adjusted so that the heating-side coefficient of performance (COP) of the heat pump 40 is maximized. It is After the flow rate and the like are adjusted, the flow rate of the dilution air introduced into the dilution air introduction pipe 60 is set at a constant flow rate.

The heated dilution air is introduced into combustion device 50 . Dilution air is introduced into gap 53 between combustion liner 51 and casing 52 and flows downstream in gap 53 .

Combustion air is introduced into the combustion liner 51 of the combustion device 50 through a fuel introduction pipe 110 and a combustion air introduction pipe 100 . The combustion air flowing through the combustion air introduction pipe 100 is heated by the exhaust gas flowing through the exhaust pipe 140 via the heat exchanger 141 . By introducing the combustion air heated by the exhaust gas into the combustion device 50, the heat quantity of the exhaust gas can be effectively used and the fuel flow rate can be reduced.

The fuel and combustion air combust within the combustion liner 51 to produce combustion gases. Mixed gas containing combustion gas and dilution air is introduced from combustion device 50 into drying furnace 20 by fan 131 as drying gas. This mixed gas also includes the drying gas circulated to the combustion device 50 via the drying gas circulation pipe 150 and the dilution air introduction pipe 60 . Here, the temperature of the combustion gas is lowered by mixing the combustion gas with the dilution air. Thereby, the temperature of the mixed gas containing the combustion gas and the dilution air is adjusted to the temperature required in the drying furnace 20 .

The temperature of the drying gas flowing through the drying gas introduction pipe 130 is detected by a gas temperature detector 132 .

The drying gas introduced into the drying furnace 20 is jetted toward the work W moving inside the drying furnace 20 . Then, for example, the coating film applied to the work W is dried while moving inside the drying furnace 20 .

Here, the damper 121 provided in the branch pipe 120 is in a closed state during steady operation. That is, during steady-state operation, air used as combustion air in the combustion device 50 is introduced from the blower 101 into the combustion air introduction pipe 100 and through the branch pipe 120 into the dilution air introduction pipe 60. does not flow.

Here, steady operation means operation in a state where the VOC concentration in the exhaust gas is maintained at the VOC concentration threshold value.

The drying gas that has dried the work W in the drying furnace 20 is discharged into the atmosphere as exhaust gas through the exhaust pipe 140 by the exhaust fan 142 . A VOC concentration detector 143 detects the VOC concentration contained in the exhaust gas flowing through the exhaust pipe 140 .

On the other hand, the drying gas that has dried the work W in the drying furnace 20 is introduced into the dilution air introduction pipe 60 through the drying gas circulation pipe 150 by the fan 131 . The circulated drying gas is introduced into the combustion device 50 together with the dilution air flowing through the dilution air introduction pipe 60 . That is, the circulated drying gas is again introduced into the drying furnace 20 as the drying gas.

Next, the action of the cooling furnace 30 will be described.

The air drawn into the cooling air introduction pipe 80 from the atmosphere by the fan 81 is cooled through the air cooling heat exchanger 72 to become cooling air.

The flow rate and temperature of the refrigerant flowing through the refrigerant circulation pipe 71 are adjusted so that the air flowing through the cooling air introduction pipe 80 can be properly cooled while maintaining the maximum cooling-side coefficient of performance (COP) of the heat pump 40. It is

Cooling air is introduced into the cooling furnace 30 through a cooling air introduction pipe 80 . The cooling air introduced into the cooling furnace 30 is jetted toward the work W moving inside the cooling furnace 30 . The work W dried in the drying furnace 20 is introduced into the cooling furnace 30 as shown in FIG.

The cooling air that has cooled the work W in the cooling furnace 30 is discharged into the atmosphere through the cooling air discharge pipe 90 by the exhaust fan 91 .

Next, the operation of the drying equipment 10 based on the VOC concentration in the exhaust gas flowing through the exhaust pipe 140 will be described.

FIG. 3 is a flow chart for explaining the operation of the drying equipment 10 of the first embodiment for maintaining the VOC concentration in the exhaust gas at the VOC concentration threshold value. FIG. 4 is a flow chart for explaining the operation of adjusting the temperature of the drying gas among the operations for maintaining the VOC concentration in the exhaust gas at the VOC concentration threshold in the drying equipment 10 of the first embodiment. .

As shown in FIG. 3, the VOC concentration determination unit 181 of the control unit 160 performs the following operations based on the detection signal from the VOC concentration detector 143 input at the input unit 170 and the VOC concentration threshold value stored in the threshold storage unit 191. It is determined whether or not the VOC concentration in the exhaust gas is the VOC concentration threshold (step S200).

Here, when the drying equipment 10 is in operation, the input section 170 of the control section 160 constantly receives the detection signal from the VOC concentration detector 143 .

When it is determined in step S200 that the VOC concentration in the exhaust gas is equal to the VOC concentration threshold value (Yes in step S200), the VOC concentration determination unit 181 executes the determination in step S200 again.

When it is determined in step S200 that the VOC concentration in the exhaust gas is not the VOC concentration threshold value (No in step S200), the detection signal from the VOC concentration detector 143 and the VOC concentration threshold value stored in the threshold storage unit 191 Based on this, it is determined whether or not the VOC concentration in the exhaust gas is lower than the VOC concentration threshold (step S201).

If it is determined in step S201 that the VOC concentration in the exhaust gas is not lower than the VOC concentration threshold value, that is, if it is determined that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold value (No in step S201), the VOC concentration is determined. Based on the difference between the VOC concentration in the exhaust gas detected by the VOC concentration detector 143 and the VOC concentration threshold (VOC concentration difference) and the exhaust gas flow rate/VOC concentration correlation table stored in the flow correlation storage section 192 , a signal for controlling the exhaust fan 142 is output to the output unit 171 (step S202). Then, the output unit 171 outputs the signal to the exhaust fan 142 (step S202).

At this time, the VOC concentration determination unit 181 outputs a signal for increasing the rotation speed of the exhaust fan 142 to the output unit 171 based on, for example, the VOC concentration difference and the exhaust gas flow rate/VOC concentration correlation table.

Further, when it is determined in step S201 that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold value (No in step S201), the VOC concentration determination unit 181 determines the flow rate of the exhaust gas (for example, the rotation speed of the exhaust fan 142) And based on the exhaust gas flow rate/air flow rate correlation table stored in the flow rate correlation storage section 192, a signal for controlling the blower 101 is output to the output section 171 (step S203). Then, the output unit 171 outputs the signal to the blower 101 (step S203).

At this time, based on the exhaust gas flow rate and the exhaust gas flow rate/air flow rate correlation table, the VOC concentration determination unit 181 outputs a signal to the output unit 171 to cause the blower 101 to discharge air at the same flow rate as the exhaust gas flow rate. In addition, the flow rate here is a volumetric flow rate.

Subsequently, the temperature determination unit 182 of the control unit 160 executes temperature adjustment of the drying gas based on the detection signal from the gas temperature detector 132 and the gas temperature threshold stored in the threshold storage unit 191 (step S204). ).

Here, the operation of adjusting the temperature of the drying gas in step S204 (steps S204A to S204E) will be described with reference to FIG.

In step S203, when the flow rate of the air discharged from the blower 101 is increased, as shown in FIG. 171 (step S204A). Then, the output unit 171 outputs the signal to the damper 121 (step S204A).

Here, the opening degree of the damper 121 is controlled so that air in excess of the combustion air required for combustion introduced into the combustion liner 51 flows into the dilution air introduction pipe 60 via the branch pipe 120. be. It should be noted that the damper 121 is closed during steady operation.

Subsequently, the temperature determination unit 182 determines whether the temperature of the drying gas is the gas temperature threshold based on the detection signal from the gas temperature detector 132 and the gas temperature threshold stored in the threshold storage unit 191. (step S204B).

When it is determined in step S204B that the temperature of the drying gas is equal to the gas temperature threshold (Yes in step S204B), the temperature determination unit 182 performs the determination in step S204B again.

When it is determined in step S204B that the temperature of the drying gas is not the gas temperature threshold (No in step S204B), the temperature determination unit 182 stores the detection signal from the gas temperature detector 132 and the threshold storage unit 191. Based on the obtained gas temperature threshold, it is determined whether or not the temperature of the drying gas is lower than the gas temperature threshold (step S204C).

When it is determined in step S204C that the temperature of the drying gas is lower than the gas temperature threshold (Yes in step S204C), the temperature determination unit 182 calculates the temperature difference between the temperature of the drying gas and the gas temperature threshold. (Step S204D). Based on the calculated temperature difference and the fuel flow rate/gas temperature correlation table stored in the flow correlation storage section 192, the temperature determination section 182 outputs a signal for controlling the flow control valve 111 to increase the fuel flow rate. Output to the output unit 171 (step S204D). The output unit 171 outputs the signal to the flow control valve 111 (step S204D).

Here, the temperature determining section 182 obtains information related to the fuel flow rate based on the output signal from the fuel flow meter 112 input from the input section 170 .

In addition, based on the fuel flow rate/air flow rate correlation table stored in the fuel flow rate/flow rate correlation storage section 192 , the temperature determination section 182 increases the opening of the damper 102 to introduce combustion gas into the combustion liner 51 . A signal for increasing the flow rate of air is output to the output unit 171 (step S204D). The output unit 171 then outputs the signal to the damper 102 (step S204D).

At this time, the temperature determination unit 182 adjusts the opening of the damper 121 so that the combustion air required for combustion is introduced into the combustion liner 51 .

After executing step S204D, the temperature determination unit 182 executes the determination of step S204B again.

If it is determined in step S204C that the temperature of the drying gas is not lower than the gas temperature threshold, that is, if it is determined that the temperature of the drying gas is higher than the gas temperature threshold (No in step S204C), the temperature determination unit 182 calculates the temperature difference between the drying gas temperature and the gas temperature threshold (step S204E). Based on the calculated temperature difference and the fuel flow/gas temperature correlation table stored in the flow correlation storage unit 192, the temperature determination unit 182 outputs a signal for controlling the flow control valve 111 to reduce the fuel flow. Output to the output unit 171 (step S204E). The output unit 171 outputs the signal to the flow control valve 111 (step S204E).

Here, the temperature determining section 182 obtains information related to the fuel flow rate based on the output signal from the fuel flow meter 112 input from the input section 170 .

Further, the temperature determining unit 182 reduces the opening of the damper 102 based on the fuel flow/air flow correlation table stored in the fuel flow/flow correlation storage unit 192 to reduce the combustion gas introduced into the combustion liner 51 . A signal for decreasing the flow rate of air is output to the output unit 171 (step S204E). The output unit 171 then outputs the signal to the damper 102 (step S204E).

At this time, the temperature determination unit 182 adjusts the opening of the damper 121 so that the combustion air required for combustion is introduced into the combustion liner 51 .

After executing step S204E, the temperature determination unit 182 executes the determination of step S204B again.

After executing the temperature adjustment of the drying gas in step S204 (steps S204A to S204E), as shown in FIG. It is determined whether or not there is a signal for ending operation (step S205).

When it is determined in step S205 that there is a signal indicating that the operation of the drying equipment 10 has ended (Yes in step S205), the VOC concentration determining unit 181 executes processing for ending the operation of the drying equipment 10.

Note that the process for ending the operation of the drying equipment 10 may be executed by a determination unit other than the VOC concentration determination unit 181. FIG.

If it is determined in step S205 that there is no signal indicating that the operation of the drying equipment 10 is finished (No in step S205), the VOC concentration determination section 181 executes the processing from step S200 again.

When it is determined in step S201 that the VOC concentration in the exhaust gas is lower than the VOC concentration threshold value (Yes in step S201), the VOC concentration determining unit 181 determines that the VOC concentration in the exhaust gas detected by the VOC concentration detector 143 A signal for controlling the exhaust fan 142 is output to the output unit 171 based on the difference from the VOC concentration threshold (VOC concentration difference) and the exhaust gas flow rate/VOC concentration correlation table stored in the flow correlation storage unit 192 (step S206). Then, the output unit 171 outputs the signal to the exhaust fan 142 (step S206).

At this time, the VOC concentration determination unit 181 outputs a signal for decreasing the rotation speed of the exhaust fan 142 to the output unit 171 based on, for example, the VOC concentration difference and the exhaust gas flow rate/VOC concentration correlation table.

Further, when it is determined in step S201 that the VOC concentration in the exhaust gas is lower than the VOC concentration threshold value (Yes in step S201), the VOC concentration determination unit 181 determines the flow rate of the exhaust gas (for example, the rotation speed of the exhaust fan 142) And based on the exhaust gas flow rate/air flow rate correlation table stored in the flow rate correlation storage section 192, a signal for controlling the blower 101 is output to the output section 171 (step S207). Then, the output unit 171 outputs the signal to the blower 101 (step S207).

At this time, based on the exhaust gas flow rate and the exhaust gas flow rate/air flow rate correlation table, the VOC concentration determination unit 181 outputs a signal to the output unit 171 to cause the blower 101 to discharge air at the same flow rate as the exhaust gas flow rate.

Subsequently, the temperature determination unit 182 of the control unit 160 executes temperature adjustment of the drying gas based on the detection signal from the gas temperature detector 132 and the gas temperature threshold stored in the threshold storage unit 191 (step S208). ).

In addition, in step S208, the same process as the process of step S204 mentioned above is performed. That is, in step S208, the processes of steps S204A to S204E shown in FIG. 4 are executed.

At this time, the temperature determination unit 182 appropriately adjusts the opening of the damper 121 of the branch pipe 120 when air exceeding the air flow rate required as the combustion air is introduced from the blower 101 into the combustion air introduction pipe 100. A signal for adjustment is output to the output unit 171 (step S204A). On the other hand, the temperature determination unit 182 outputs a signal for closing the damper 121 of the branch pipe 120 when only the air flow rate required as the combustion air is introduced from the blower 101 into the combustion air introduction pipe 100. Output to the output unit 171 (step S204A).

After executing the temperature adjustment of the drying gas in step S208, as shown in FIG. (step S209).

If it is determined in step S209 that there is a signal indicating that the operation of the drying equipment 10 has ended (Yes in step S209), a process for ending the operation of the drying equipment 10 is executed.

If it is determined in step S209 that there is no signal indicating that the operation of the drying equipment 10 is finished (No in step S209), the VOC concentration determination unit 181 executes the processing from step S200 again.

As described above, in the drying equipment 10 of the first embodiment, the VOC concentration in exhaust gas can be maintained at the VOC concentration threshold.

In the drying equipment 10, for example, when the VOC concentration in the exhaust gas is higher than the VOC concentration threshold, the flow rate of the exhaust gas discharged from the drying furnace 20 is increased, and the flow rate of the drying gas introduced into the drying furnace 20 is increased. can be done.

On the other hand, when the VOC concentration in the exhaust gas is lower than the VOC concentration threshold, the flow rate of the exhaust gas discharged from the drying furnace 20 can be reduced, and the flow rate of the drying gas introduced into the drying furnace 20 can be reduced.

Further, in the drying equipment 10, the flow rate of the exhaust gas discharged from the drying furnace 20 and the flow rate of the drying gas introduced into the drying furnace 20 are appropriately adjusted based on the difference between the VOC concentration in the exhaust gas and the VOC concentration threshold. can be done.

Here, cases where the VOC concentration becomes higher than the VOC concentration threshold include the case where many works W are dried at once in the drying furnace 20, the case where the size of the work W to be dried is large, and the like. In these cases, a large amount of VOC contained in the coating film evaporates in the drying oven 20, so the VOC concentration becomes higher than the VOC concentration threshold.

On the other hand, cases where the VOC concentration is lower than the VOC concentration threshold include a case where the number of works W to be dried at one time in the drying furnace 20 is small, a case where the size of the works W to be dried is small, and the like. In these cases, less VOC is generated in the drying furnace 20 and the VOC concentration is lower than the VOC concentration threshold.

In any case, by adjusting the flow rate of the exhaust gas discharged from the drying furnace 20 and the flow rate of the drying gas introduced into the drying furnace 20 according to the VOC concentration in the exhaust gas, the VOC concentration in the exhaust gas, that is, the drying The VOC concentration within the furnace 20 can be maintained at the VOC concentration threshold.

The drying equipment 10 is not equipped with a device for recovering and removing VOCs contained in the exhaust gas. The VOC concentration in the exhaust gas can be maintained at the VOC concentration threshold.

In addition, in the drying equipment 10, the blower 101 discharges air at the same flow rate as the exhaust gas, so that the drying gas at the same flow rate as the exhaust gas discharged from the drying furnace 20 can be introduced into the drying furnace 20. Thereby, the pressure inside the drying furnace 20 can be kept constant.

Further, the drying equipment 10 is provided with a branch pipe 120, and by adjusting the opening degree of the damper 121, air necessary for combustion is introduced into the combustion liner 51, and surplus air is introduced into the dilution air introduction pipe 60. can be introduced. That is, an appropriate flow rate of air can be introduced into the combustion liner 51 while increasing the flow rate of the drying gas.

In step S204 (steps S204A to S204E) and step S208, the drying equipment 10 is provided with the temperature determination unit 182, and adjusts the fuel flow rate and the combustion air flow rate to reduce the VOC concentration in the drying furnace 20 to the VOC concentration threshold value. Drying gas at a temperature of the gas temperature threshold can be introduced into the drying oven 20 even when the flow rate of the drying gas is increased or decreased to maintain a constant temperature. Further, in the drying equipment 10, for example, the flow rate of the fuel introduced into the combustion device 50 can be appropriately set based on the difference between the temperature of the drying gas introduced into the drying furnace 20 and the gas temperature threshold.

As a result, the work W can be properly dried even when the process for maintaining the VOC concentration in the drying furnace 20 at the VOC concentration threshold value is being executed.

In the drying equipment 10 , the air flowing through the combustion air introduction pipe 100 is heated by the exhaust gas flowing through the exhaust pipe 140 via the heat exchanger 141 . This makes it possible to effectively utilize the heat quantity of the exhaust gas. Furthermore, since the heated air is introduced into the combustion device 50, the flow rate of fuel introduced into the combustion device 50 can be reduced.

Further, in the drying equipment 10, by providing a simple configuration while maintaining the conditions for maximizing the coefficient of performance (COP) of the heat pump 40, it is possible to perform processing for maintaining the VOC concentration at the VOC concentration threshold. can.

In addition, even in existing drying equipment that does not have a function to remove VOCs, it is equipped with a configuration for maintaining the VOC concentration shown in the first embodiment at the VOC concentration threshold value without large-scale expansion work. be able to.

That is, by providing the existing drying equipment with, for example, the branch pipe 120 having the damper 121 and the control unit 160, the existing drying equipment can be used in the first embodiment without increasing the size and complexity. Arrangements may be provided for maintaining the indicated VOC concentration at the VOC concentration threshold.

(Second embodiment)
FIG. 5 is a diagram schematically showing the outline of the drying equipment 11 of the second embodiment. In addition, in the second embodiment, the same components as those of the drying equipment 10 of the first embodiment are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified.

In the drying equipment 11 of the second embodiment, the combustion air introduction system and the air (dilution air) increased when the VOC concentration in the exhaust gas exceeds the VOC concentration threshold is introduced into the first dilution air introduction system. The configuration of the introduction system introduced into the pipe 60A is different from the configuration of the drying equipment 10 of the first embodiment. This different configuration is mainly described here.

As shown in FIG. 5 , the drying equipment 10 includes a drying furnace 20 and a cooling furnace 30 . In addition, the drying equipment 10 includes a combustion device 50, a combustion air introduction pipe 300, a fuel introduction pipe 110, a first dilution air introduction pipe 60A, a second dilution air introduction pipe 310, a drying A gas introduction pipe 130 , an exhaust pipe 140 and a drying gas circulation pipe 150 are provided. The drying equipment 10 also includes a control unit 160 that controls the drying equipment 10 .

The first dilution air introduction pipe 60A has the same configuration as the dilution air introduction pipe 60 in the drying equipment 10 of the first embodiment. Also, the action of the first dilution air introduction pipe 60A is the same as the action of the dilution air introduction pipe 60 in the drying equipment 10 of the first embodiment.

Here, the combustion air introduction pipe 300 and the second dilution air introduction pipe 310 will be mainly described.

Combustion air introduction pipe 300 introduces combustion air into combustion device 50 . Specifically, the combustion air introduction pipe 300 is connected to the combustion liner 51 and introduces air into the combustion liner 51 . The combustion air introduction pipe 300 is provided with a blower 301 that introduces outside air into the combustion air introduction pipe 300 and guides it to the combustion device 50 . Note that the blower 301 functions as a first air supplier. A fan, for example, may be used as the first air supplier.

The second dilution air introduction pipe 310 is provided so as to introduce air (dilution air) into the first dilution air introduction pipe 60A. Specifically, the second dilution air introduction pipe 310 is connected to the first dilution air introduction pipe 60A between the heat pump 40 and the combustion device 50 .

The second dilution air introduction pipe 310 is provided with a blower 311 that introduces outside air into the second dilution air introduction pipe 310 and guides it to the first dilution air introduction pipe 60A. Note that the blower 311 functions as a second air supplier. A fan, for example, may be used as the second air supply.

A portion of the second dilution air introduction pipe 310 is configured to be heat exchangeable with the drying gas flowing through the exhaust pipe 140, as shown in FIG. The second dilution air introduction pipe 310 is arranged, for example, so as to pass through a heat exchanger 141 provided in the exhaust pipe 140 . The air flowing through the second dilution air introduction pipe 310 is heated by the exhaust gas via the heat exchanger 141 .

The air flowing through the second dilution air introduction pipe 310 is introduced into the combustion device 50 as dilution air together with the air flowing through the first dilution air introduction pipe 60A.

Here, the blower 311 provided in the second dilution air introduction pipe 310 guides air having the same flow rate as the flow rate of the exhaust gas discharged by the exhaust fan 142 into the second dilution air introduction pipe 310. activated. That is, the blower 311 is constantly operating under the operating conditions in which the exhaust gas is exhausted from the drying furnace 20 .

Here, the drying gas circulation pipe 150 is arranged, for example, on the side of the heat pump 40 from the position where the second dilution air introduction pipe 310 is connected to the first dilution air introduction pipe 60A. Connected to tube 60A. Note that the connecting portion of the drying gas circulation pipe 150 with the first dilution air introduction pipe 60A is more combustible than the connection portion of the second dilution air introduction pipe 310 with the first dilution air introduction pipe 60A. It may be on the device 50 side.

The controller 160 controls, for example, the exhaust fan 142 and the blower 311 based on the signal detected by the VOC concentration detector 143 . Also, the control unit 160 controls, for example, the blower 301 and the flow control valve 111 based on the signal detected by the gas temperature detector 132 .

Here, also in the drying equipment 11 of the second embodiment, the control section 160 includes an input section 170, a calculation section 180, a storage section 190, and an output section 171, similarly to the configuration shown in FIG.

Here, the difference between the function of each component of the control unit 160 of the drying equipment 11 of the second embodiment and the function of each component of the control unit 160 of the drying equipment 10 of the first embodiment will be described. Mainly explained.

As described above, the storage unit 190 includes the threshold storage unit 191 and the flow correlation storage unit 192 (see FIG. 2).

The flow rate correlation storage unit 192 stores an exhaust gas flow rate/air flow rate correlation table for introducing air having the same flow rate as the flow rate of the exhaust gas discharged by the exhaust fan 142 into the second dilution air introduction pipe 310 from the blower 311. ing.

Specifically, the exhaust gas flow rate/air flow rate correlation table is composed of correlation data that defines the number of rotations of the blower 311 for discharging air at the same flow rate as the exhaust gas flow rate. For example, the exhaust gas flow rate/air flow rate correlation table is composed of correlation data that defines the correspondence between the rotation speed of the exhaust fan 142 and the rotation speed of the blower 311 .

Further, the flow rate correlation storage unit 192 stores, for example, a fuel flow rate/air flow rate correlation table for setting the flow rate of combustion air based on the fuel flow rate. The fuel flow rate/air flow rate correlation table is composed of, for example, correlation data that defines the air flow rate corresponding to the fuel flow rate. Specifically, the fuel flow rate/air flow rate correlation table is composed of correlation data that determines the rotation speed of the blower 301 based on the fuel flow rate.

As described above, the calculation unit 180 includes the VOC concentration determination unit 181 and the temperature determination unit 182 (see FIG. 2).

Based on the VOC concentration threshold stored in the threshold storage unit 191 and the detection signal from the VOC concentration detector 143, the VOC concentration determination unit 181 determines whether the VOC concentration in the exhaust gas is equal to the VOC concentration threshold. Determine whether the VOC concentration is higher than the VOC concentration threshold or lower than the VOC concentration threshold.

Then, if it is determined that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold or if it is determined that the VOC concentration in the exhaust gas is lower than the VOC concentration threshold, the VOC concentration determination unit 181 determines the VOC concentration in the exhaust gas and the VOC concentration A signal for controlling the exhaust fan 142 is output to the output section 171 based on the difference from the concentration threshold and the exhaust gas flow rate/VOC concentration correlation table stored in the flow rate correlation storage section 192 .

Further, when it is determined that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold value or when it is determined that the VOC concentration in the exhaust gas is lower than the VOC concentration threshold value, the VOC concentration determination unit 181 determines the flow rate of the exhaust gas (for example, the exhaust gas A signal for controlling the blower 311 is output to the output unit 171 based on the rotation speed of the fan 142) and the exhaust gas flow rate/air flow rate correlation table.

The temperature determination unit 182 determines, for example, whether the temperature of the drying gas is the gas temperature threshold based on the gas temperature threshold stored in the threshold storage unit 191 and the detection signal from the gas temperature detector 132. . Also, the temperature determination unit 182 determines, for example, whether the temperature of the drying gas is higher or lower than the gas temperature threshold.

Then, for example, when the VOC concentration determination unit 181 determines that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold value, and determines that the temperature of the drying gas is higher or lower than the gas temperature threshold value, Based on the difference between the detected drying gas temperature and the gas temperature threshold, and the fuel flow/gas temperature correlation table and the fuel flow/air flow correlation table stored in the flow correlation storage unit 192, the temperature determination unit 182 determines: It controls the blower 301 and the flow control valve 111 .

For example, when determining that the temperature of the drying gas is higher than the gas temperature threshold, the temperature determination unit 182 sends a signal to the output unit 171 to throttle the flow rate adjustment valve 111 based on the fuel flow rate/gas temperature correlation table. In addition to outputting, a signal for decreasing the rotational speed of the blower 301 is output to the output section 171 based on the fuel flow rate/air flow rate correlation table.

Further, when it is determined that the exhaust gas temperature is lower than the exhaust gas temperature threshold, the temperature determination unit 182 outputs a signal for opening the flow rate adjustment valve 111 to the output unit 171 based on the fuel flow rate/gas temperature correlation table. At the same time, a signal for increasing the rotational speed of the blower 301 is output to the output section 171 based on the fuel flow rate/air flow rate correlation table.

The output unit 171 outputs the control signal from the VOC concentration determination unit 181 to the exhaust fan 142 and the blower 311, for example. Also, the output unit 171 outputs the control signal from the temperature determination unit 182 to the flow control valve 111 and the blower 301, for example.

Next, the operation of the drying equipment 11 based on the VOC concentration in the exhaust gas flowing through the exhaust pipe 140 will be described.

Here, the operation of the drying equipment 11 of the second embodiment will be described with reference to FIGS. 3 and 4 shown in the description of the operation of the drying equipment 10 of the first embodiment.

As shown in FIG. 3, the VOC concentration determination unit 181 of the control unit 160 performs the following operations based on the detection signal from the VOC concentration detector 143 input at the input unit 170 and the VOC concentration threshold value stored in the threshold storage unit 191. It is determined whether or not the VOC concentration in the exhaust gas is the VOC concentration threshold (step S200).

Here, when the drying equipment 10 is in operation, the input section 170 of the control section 160 constantly receives the detection signal from the VOC concentration detector 143 .

When it is determined in step S200 that the VOC concentration in the exhaust gas is equal to the VOC concentration threshold value (Yes in step S200), the VOC concentration determination unit 181 executes the determination in step S200 again.

When it is determined in step S200 that the VOC concentration in the exhaust gas is not the VOC concentration threshold value (No in step S200), the detection signal from the VOC concentration detector 143 and the VOC concentration threshold value stored in the threshold storage unit 191 Based on this, it is determined whether or not the VOC concentration in the exhaust gas is lower than the VOC concentration threshold (step S201).

If it is determined in step S201 that the VOC concentration in the exhaust gas is not lower than the VOC concentration threshold value, that is, if it is determined that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold value (No in step S201), the VOC concentration is determined. Based on the difference between the VOC concentration in the exhaust gas detected by the VOC concentration detector 143 and the VOC concentration threshold (VOC concentration difference) and the exhaust gas flow rate/VOC concentration correlation table stored in the flow correlation storage section 192 , a signal for controlling the exhaust fan 142 is output to the output unit 171 (step S202). Then, the output unit 171 outputs the signal to the exhaust fan 142 (step S202).

At this time, the VOC concentration determination unit 181 outputs a signal for increasing the rotation speed of the exhaust fan 142 to the output unit 171 based on, for example, the VOC concentration difference and the exhaust gas flow rate/VOC concentration correlation table.

Further, when it is determined in step S201 that the VOC concentration in the exhaust gas is higher than the VOC concentration threshold value (No in step S201), the VOC concentration determination unit 181 determines the flow rate of the exhaust gas (for example, the rotation speed of the exhaust fan 142) A signal for controlling the blower 311 is output to the output section 171 based on the exhaust gas flow rate/air flow rate correlation table stored in the flow rate correlation storage section 192 (step S203). Then, the output unit 171 outputs the signal to the blower 311 (step S203).

At this time, based on the exhaust gas flow rate and the exhaust gas flow rate/air flow rate correlation table, the VOC concentration determination unit 181 outputs a signal to the output unit 171 to cause the blower 311 to discharge air at the same flow rate as the exhaust gas flow rate.

Subsequently, the temperature determination unit 182 of the control unit 160 executes temperature adjustment of the drying gas based on the detection signal from the gas temperature detector 132 and the gas temperature threshold stored in the threshold storage unit 191 (step S204). ).

Here, the operation of adjusting the temperature of the drying gas in step S204 will be described with reference to FIG.

In the drying equipment 11, the processing in step S204A of FIG. 4 is not executed. Therefore, in the drying equipment 11, the processing from step S204B in FIG. 4 is executed.

The temperature determination unit 182 determines whether the temperature of the drying gas is the gas temperature threshold based on the detection signal from the gas temperature detector 132 and the gas temperature threshold stored in the threshold storage unit 191 (step S204B).

When it is determined in step S204B that the temperature of the drying gas is equal to the gas temperature threshold (Yes in step S204B), the temperature determination unit 182 performs the determination in step S204B again.

When it is determined in step S204B that the temperature of the drying gas is not the gas temperature threshold (No in step S204B), the temperature determination unit 182 stores the detection signal from the gas temperature detector 132 and the threshold storage unit 191. Based on the obtained gas temperature threshold, it is determined whether or not the temperature of the drying gas is lower than the gas temperature threshold (step S204C).

When it is determined in step S204C that the temperature of the drying gas is lower than the gas temperature threshold (Yes in step S204C), the temperature determination unit 182 calculates the temperature difference between the temperature of the drying gas and the gas temperature threshold. (Step S204D). Based on the calculated temperature difference and the fuel flow rate/gas temperature correlation table stored in the flow correlation storage section 192, the temperature determination section 182 outputs a signal for controlling the flow control valve 111 to increase the fuel flow rate. Output to the output unit 171 (step S204D). The output unit 171 outputs the signal to the flow control valve 111 (step S204D).

In addition, the temperature determining unit 182 increases the rotational speed of the blower 301 based on the fuel flow rate/air flow rate correlation table stored in the fuel flow rate/flow rate correlation storage unit 192 to increase the rotation speed of the blower 301 so as to introduce combustion fuel into the combustion liner 51 . A signal for increasing the flow rate of air is output to the output unit 171 (step S204D). Then, the output unit 171 outputs the signal to the blower 301 (step S204D).

After executing step S204D, the temperature determination unit 182 executes the determination of step S204B again.

If it is determined in step S204C that the temperature of the drying gas is not lower than the gas temperature threshold, that is, if it is determined that the temperature of the drying gas is higher than the gas temperature threshold (No in step S204C), the temperature determination unit 182 calculates the temperature difference between the drying gas temperature and the gas temperature threshold (step S204E). Based on the calculated temperature difference and the fuel flow/gas temperature correlation table stored in the flow correlation storage unit 192, the temperature determination unit 182 outputs a signal for controlling the flow control valve 111 to reduce the fuel flow. Output to the output unit 171 (step S204E). The output unit 171 outputs the signal to the flow control valve 111 (step S204E).

In addition, the temperature determining unit 182 reduces the rotation speed of the blower 301 based on the fuel flow rate/air flow rate correlation table stored in the fuel flow rate/flow rate correlation storage unit 192 to reduce the combustion gas introduced into the combustion liner 51 . A signal for decreasing the flow rate of air is output to the output unit 171 (step S204E). Then, the output unit 171 outputs the signal to the blower 301 (step S204E).

After executing step S204E, the temperature determination unit 182 executes the determination of step S204B again.

After executing the temperature adjustment of the drying gas in step S204 (steps S204B to S204E), as shown in FIG. It is determined whether or not there is a signal for ending operation (step S205).

When it is determined in step S205 that there is a signal indicating that the operation of the drying equipment 10 has ended (Yes in step S205), the VOC concentration determining unit 181 executes processing for ending the operation of the drying equipment 10.

Note that the process for ending the operation of the drying equipment 10 may be executed by a determination unit other than the VOC concentration determination unit 181. FIG.

If it is determined in step S205 that there is no signal indicating that the operation of the drying equipment 10 is finished (No in step S205), the VOC concentration determination section 181 executes the processing from step S200 again.

When it is determined in step S201 that the VOC concentration in the exhaust gas is lower than the VOC concentration threshold value (Yes in step S201), the VOC concentration determining unit 181 determines that the VOC concentration in the exhaust gas detected by the VOC concentration detector 143 A signal for controlling the exhaust fan 142 is output to the output unit 171 based on the difference from the VOC concentration threshold (VOC concentration difference) and the exhaust gas flow rate/VOC concentration correlation table stored in the flow correlation storage unit 192 (step S206). Then, the output unit 171 outputs the signal to the exhaust fan 142 (step S206).

At this time, the VOC concentration determination unit 181 outputs a signal for decreasing the rotation speed of the exhaust fan 142 to the output unit 171 based on, for example, the VOC concentration difference and the exhaust gas flow rate/VOC concentration correlation table.

Further, when it is determined in step S201 that the VOC concentration in the exhaust gas is lower than the VOC concentration threshold value (Yes in step S201), the VOC concentration determination unit 181 determines the flow rate of the exhaust gas (for example, the rotation speed of the exhaust fan 142) And based on the exhaust gas flow rate/air flow rate correlation table stored in the flow rate correlation storage section 192, a signal for controlling the blower 311 is output to the output section 171 (step S207). Then, the output unit 171 outputs the signal to the blower 311 (step S207).

At this time, based on the exhaust gas flow rate and the exhaust gas flow rate/air flow rate correlation table, the VOC concentration determination unit 181 outputs a signal to the output unit 171 to cause the blower 311 to discharge air at the same flow rate as the exhaust gas flow rate.

Subsequently, the temperature determination unit 182 of the control unit 160 executes temperature adjustment of the drying gas based on the detection signal from the gas temperature detector 132 and the gas temperature threshold stored in the threshold storage unit 191 (step S208). ).

In addition, in step S208, the same process as the process of step S204 mentioned above is performed. That is, in step S208, the processes of steps S204B to S204E shown in FIG. 4 are executed.

After executing the temperature adjustment of the drying gas in step S208, as shown in FIG. (step S209).

If it is determined in step S209 that there is a signal for ending the operation of the drying equipment 10 (Yes in step S209), a process for ending the operation of the drying equipment 10 is executed.

If it is determined in step S209 that there is no signal indicating that the operation of the drying equipment 10 has ended (No in step S209), the VOC concentration determination unit 181 executes the processing from step S200 again.

In addition, during the VOC concentration adjustment operation in the drying equipment 11 of the second embodiment, the flow rate of the drying gas introduced into the drying furnace 20 is higher than the flow rate of the exhaust gas discharged by the exhaust fan 142 depending on the operating conditions. may increase.

In such a case, the excess drying gas may be introduced, for example, into a setting zone provided on the upstream side of the drying furnace 20 (upstream side in the transport direction of the workpiece W). Thereby, the pressure in the drying furnace 20 can be kept constant.

In the drying equipment 11 of the second embodiment, effects similar to those of the drying equipment 10 of the first embodiment can be obtained.

In addition, in the drying equipment 11, the second dilution air introduction pipe 310 through which the air introduced from the outside air flows by the blower 311 and the combustion air introduction pipe 300 for introducing the combustion air into the combustion device 50 are separated. It consists of separate systems.

As a result, the flow rate of the air introduced into the first dilution air introduction pipe 60A through the second dilution air introduction pipe 310 and the combustion flow introduced into the combustion device 50 through the combustion air introduction pipe 300 The air flow rate can be independently controlled.

In the drying equipment 11 , the air flowing through the second dilution air introduction pipe 310 is heated by the exhaust gas flowing through the exhaust pipe 140 via the heat exchanger 141 . This makes it possible to effectively utilize the heat quantity of the exhaust gas. Furthermore, since the heated air is introduced into the combustion device 50, the flow rate of fuel introduced into the combustion device 50 can be reduced.

While several embodiments of the invention have been described, these embodiments have been presented by way of example 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 modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 10, 11... Drying equipment, 20... Drying furnace, 30... Cooling furnace, 40... Heat pump, 41... Refrigerant flow path, 42... Condenser, 43... Evaporator, 44... Compressor, 45... Expansion valve, 50... Combustion Apparatus 51 Combustion liner 52 Casing 53 Gap 60 Dilution air introduction pipe 60A First dilution air introduction pipe 61, 81, 131 Fan 70 Air cooling mechanism 71 Refrigerant circulation pipe 72 Air cooling heat exchanger 73 Circulation pump 74 Refrigerant heating heat exchanger 80 Cooling air introduction pipe 90 Cooling air discharge pipe 91, 142 Exhaust fan 100, 300 Combustion air introduction pipe 101, 301, 311 Blower 102, 121 Damper 110 Fuel introduction pipe 111 Flow control valve 112 Fuel flow meter 120 Branch pipe 130 Drying 132 Gas temperature detector 140 Exhaust pipe 141 Heat exchanger 143 VOC concentration detector 145 Branch exhaust pipe 146 Flow control valve 150 Drying gas circulation pipe DESCRIPTION OF SYMBOLS 160... Control part 170... Input part 171... Output part 180... Calculation part 181... VOC concentration determination part 182... Temperature determination part 190... Storage part 191... Threshold storage part 192... Flow correlation storage part , 310 . . . second dilution air introduction pipe, W .

Claims (9)

a combustion device;
a combustion air introduction pipe for introducing combustion air into the combustion device, comprising an air supplier and an air flow rate adjusting unit;
a fuel introduction pipe including a fuel flow control valve for introducing fuel into the combustion device;
a dilution air introduction pipe for introducing dilution air into the combustion device;
a heat pump equipped with a heating heat exchanger for heating the dilution air flowing through the dilution air introduction pipe;
a branch pipe branched from the combustion air introduction pipe between the air supply device and the air flow rate adjustment unit and connected to the dilution air introduction pipe;
a drying device for drying the material to be dried;
a drying gas introduction pipe for introducing a mixed gas containing combustion gas and dilution air generated in the combustion device into the drying device as drying gas;
an exhaust pipe for exhausting the drying gas from the drying device, the exhaust pipe including an exhaust blower;
a drying gas circulation pipe that introduces the drying gas from the drying device into the dilution air introduction pipe and circulates it to the combustion device;
a VOC concentration detector for detecting the concentration of volatile organic compounds contained in the drying gas related to the drying gas in the drying device;
a gas temperature detector for detecting the temperature of the drying gas related to the drying gas in the drying device;
Based on the detection signal from the VOC concentration detector, the exhaust blower and the air supply device are controlled, and based on the detection signal from the gas temperature detector, the air flow rate adjustment unit and the fuel flow rate adjustment valve are operated. A drying facility comprising: a control unit for controlling; a combustion device;
a combustion air introduction pipe including a first air supplier for introducing combustion air into the combustion device;
a fuel introduction pipe including a fuel flow control valve for introducing fuel into the combustion device;
a first dilution air introduction pipe for introducing dilution air into the combustion device;
a heat pump comprising a heating heat exchanger for heating the dilution air flowing through the first dilution air introduction pipe;
a second dilution air introduction pipe comprising a second air supplier and connected to the first dilution air introduction pipe;
a drying device for drying the material to be dried;
a drying gas introduction pipe for introducing a mixed gas containing combustion gas and dilution air generated in the combustion device into the drying device as drying gas;
an exhaust pipe for exhausting the drying gas from the drying device, the exhaust pipe including an exhaust blower;
a drying gas circulation pipe that introduces the drying gas from the drying device into the first dilution air introduction pipe and circulates it to the combustion device;
a VOC concentration detector for detecting the concentration of volatile organic compounds contained in the drying gas related to the drying gas in the drying device;
a gas temperature detector for detecting the temperature of the drying gas related to the drying gas in the drying device;
Based on the detection signal from the VOC concentration detector, the exhaust fan and the second air supplier are controlled, and based on the detection signal from the gas temperature detector, the first air supplier and the A drying facility comprising: a control unit that controls a fuel flow control valve. 3. The VOC concentration detector detects the concentration of volatile organic compounds contained in the drying gas in at least one of the exhaust pipe, the drying gas circulation pipe, and the drying device. 3. Drying equipment according to 1 or 2. 4. The method according to any one of claims 1 to 3, wherein the gas temperature detector detects the temperature of the drying gas in at least one of the drying gas introduction pipe, the drying device, and the drying gas circulation pipe. Drying equipment according to any one of the preceding claims. The drying equipment
a cooling device for cooling the material to be dried;
a cooling air introduction pipe for introducing cooling air into the cooling device;
an air cooling mechanism for cooling the cooling air flowing through the cooling air introduction pipe,
The air cooling mechanism is
a refrigerant circulation pipe for circulating the refrigerant;
a refrigerant cooling heat exchanger that is provided in the heat pump and that cools the refrigerant flowing through the refrigerant circulation pipe;
5. The dryer according to any one of claims 1 to 4, further comprising an air cooling heat exchanger that cools the cooling air flowing through the cooling air introduction pipe with the refrigerant flowing through the refrigerant circulation pipe. Facility. a combustion device;
a combustion air introduction pipe that includes an air supplier and introduces combustion air into the combustion device;
a fuel introduction pipe for introducing fuel into the combustion device;
a dilution air introduction pipe for introducing dilution air heated by a heat pump into the combustion device;
a branch pipe branched from the combustion air introduction pipe and connected to the dilution air introduction pipe;
a drying device for drying the material to be dried;
a drying gas introduction pipe for introducing a mixed gas containing combustion gas and dilution air generated in the combustion device into the drying device as drying gas;
an exhaust pipe for exhausting the drying gas from the drying device, the exhaust pipe including an exhaust blower;
a drying gas circulation pipe that introduces the drying gas from the drying device into the dilution air introduction pipe and circulates it to the combustion device;
a VOC concentration detector for detecting the concentration of volatile organic compounds contained in the drying gas related to the drying gas in the drying device;
A VOC concentration control method for a drying facility, comprising:
The VOC concentration determination unit controls the exhaust blower based on the concentration of the volatile organic compounds detected by the VOC concentration detector so that the concentration of the volatile organic compounds is maintained at a predetermined concentration. while adjusting the flow rate of the drying gas discharged from the drying device, and controlling the air supply device to introduce air having the same flow rate as the drying gas flow rate discharged from the drying device into the combustion air introduction pipe,
The temperature determination unit adjusts the temperature of the drying gas, which is detected by the gas temperature detector, so that the temperature of the drying gas is maintained at a predetermined temperature. A VOC concentration control method for drying equipment, characterized in that the flow rate is adjusted, and the flow rate of the combustion air flowing through the combustion air introduction pipe and the flow rate of the air flowing through the branch pipe are adjusted based on the fuel flow rate. . a combustion device;
a combustion air introduction pipe including a first air supplier for introducing combustion air into the combustion device;
a fuel introduction pipe for introducing fuel into the combustion device;
a first dilution air introduction pipe for introducing dilution air heated by a heat pump into the combustion device;
a second dilution air introduction pipe comprising a second air supplier and connected to the first dilution air introduction pipe;
a drying device for drying the material to be dried;
a drying gas introduction pipe for introducing a mixed gas containing combustion gas and dilution air generated in the combustion device into the drying device as drying gas;
an exhaust pipe for exhausting the drying gas from the drying device, the exhaust pipe including an exhaust blower;
a drying gas circulation pipe that introduces the drying gas from the drying device into the first dilution air introduction pipe and circulates it to the combustion device;
a VOC concentration detector for detecting the concentration of volatile organic compounds contained in the drying gas related to the drying gas in the drying device;
A VOC concentration control method for a drying facility, comprising:
The VOC concentration determination unit controls the exhaust blower based on the concentration of the volatile organic compounds detected by the VOC concentration detector so that the concentration of the volatile organic compounds is maintained at a predetermined concentration. While adjusting the flow rate of the drying gas exhausted from the drying apparatus, the second air supply unit is controlled to supply the same flow rate of air as the drying gas exhausted from the drying device to the second dilution air introduced into the introduction tube,
The temperature determination unit adjusts the temperature of the drying gas, which is detected by the gas temperature detector, so that the temperature of the drying gas is maintained at a predetermined temperature. VOC drying equipment characterized by adjusting the flow rate and controlling the flow rate of the combustion air introduced into the combustion air introduction pipe by controlling the first air supply device based on the fuel flow rate. Concentration control method. 3. The VOC concentration detector detects the concentration of volatile organic compounds contained in the drying gas in at least one of the exhaust pipe, the drying gas circulation pipe, and the drying device. 8. The VOC concentration control method for drying equipment according to 6 or 7. 9. The gas temperature detector according to any one of claims 6 to 8, wherein the gas temperature detector detects the temperature of the drying gas in at least one of the drying gas introduction pipe, the drying device and the drying gas circulation pipe. 1. VOC concentration control method for drying equipment according to claim 1.

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