JP5615020B2 - Drying equipment with continuous box dryer - Google Patents

Description

  The present invention relates to a continuous box dryer used for drying long objects such as plate materials, and in particular reduces heat loss by preventing air leaks from the inlet and outlet of the object to be processed. It relates to a drying facility provided with a continuous box-type dryer that can be operated efficiently.

For example, a continuous box dryer 1 ′ as shown in FIG. 5 is used to dry a plate material such as an outer wall material or a plaster board, or a long wire. This apparatus is provided with a conveying device 13 'such as a belt conveyor in a drying chamber 10', and an object to be processed that enters the drying chamber 10 'from an inlet 11' while being placed on the conveying device 13 '. This is an apparatus for drying B.
Then, the indoor gas G5 in the drying chamber 10 ′ is taken out of the drying chamber 10 ′ and heated to become a circulating gas G3. Thereafter, the circulating gas G3 is returned to the drying chamber 10 ′ to be processed. It is comprised so that B may be dried.
If the drying of the object to be processed B is continued by raising the temperature and circulation of the indoor gas G5, the indoor gas G5 will eventually be saturated, and a part thereof is exhausted to the outside through the exhaust port 16 '. With this exhaust, the outside air G0 is newly introduced from the inlet 11 'and the outlet 12', which are the openings of the drying chamber 10 ', and the indoor gas G5 is in a state suitable for drying because the humidity is lowered. It is what is done.

During the operation of the continuous box dryer 1 ′ in which such an operation is continued, the indoor gas G5 leaks from the open inlet 11 ′ and the outlet 12 ′, and further the indoor gas G5 Since it is in direct contact with the outside air, heat transfer occurs and heat loss occurs.
However, conventionally, such a heat loss has been recognized as unavoidable due to the structure of the continuous box dryer 1 ′, and no positive improvement has been made (see, for example, Patent Document 1).
Of course, for example, the inlet port 11 'and the outlet port 12' are intermittently blocked by an air curtain that is parallel to the opening surface, and the room gas G5 and the outside air are separated except when the outside air G0 is taken in. Can be prevented and leakage of the indoor gas G5 can be prevented. However, when the temperature of the gas used for the air curtain is low, the indoor gas G5 can be prevented from leaking, but heat transfer occurs between the indoor gas G5 and the air curtain, thereby preventing heat loss. Then it will be insufficient.
For this reason, it is necessary to bring the temperature of the air curtain close to the temperature of the indoor gas G5. However, since the heat energy of the air curtain is released to the outside of the continuous box dryer 1 ′, the heat loss is reduced in the entire system. The improvement of the energy efficiency by preventing the occurrence of the air curtain becomes slight, and the adoption of the air curtain as described above cannot be an effective means.

JP 2004-190982 A

  The present invention has been made in view of such a background, and prevents outflow of indoor gas from the inlet and outlet of the drying chamber and outflow of heat from the indoor gas in the continuous box dryer. The technical challenge is to develop a drying facility equipped with a new continuous box dryer that can improve the energy efficiency of the entire drying facility.

That is, the drying equipment provided with the continuous box-type dryer according to claim 1 includes a drying chamber in which an input port and an outlet port of an object to be processed are formed in an open state, and a passage through the drying chamber from the input port. In a drying facility provided with a continuous box dryer configured to be capable of continuous processing of long workpieces by being provided with a transport device that reaches the discharge port, A temperature rising circulation mechanism configured to take out the indoor gas in the drying chamber in the box-type dryer to the outside of the drying chamber and raise the temperature to a circulating gas, and then return the circulating gas to the drying chamber; An air supply mechanism for supplying outside air for ventilation into the drying chamber, and the air supply mechanism comprises a heat pump unit for raising the temperature of the outside air to make the temperature rise. Yes, the temperature rise outside air further A temperature raising mechanism for raising the temperature to high temperature outside air is provided. The temperature raising mechanism includes an endothermic element for removing heat from the dry exhaust gas exhausted from the drying chamber, and a temperature raising mechanism for the heat. A heat-dissipating element for releasing the gas into the gas, and a heat exchanger provided with a heat exchanger for taking in the hot water circulated and supplied to the evaporator in the heat pump unit. A heat recovery mechanism is provided, and heat is recovered from the dried exhaust gas exhausted from the drying chamber by a heat absorbing element in the temperature raising mechanism, and then in the heat exchanger in the exhaust heat recovery mechanism, the dried exhaust gas is converted into warm water. Heat is recovered, and the heat recovered in the warm water raises the temperature of the outside air in the evaporator of the heat pump unit to increase the temperature of the outside air, and then the temperature rising outside air is recovered by the heat absorbing element. With the generated heat, the temperature is raised to within ± 80 ° C. with respect to the temperature of the indoor gas in the drying chamber to form high-temperature outside air, and this high-temperature outside air is jetted from the outside of the drying chamber to the inlet and outlet. It is characterized in that it can be introduced into the drying chamber .
The above problems can be solved by using the configuration of the invention described in the above claims.

According to the present invention, the indoor air is prevented from leaking by the outside air introduced into the drying chamber from the inlet and the outlet, and the amount of heat transferred between the indoor gas and the introduced outside air is reduced. Can be suppressed.
Moreover, the energy cost required when raising the temperature of the outside air can be reduced.
Furthermore, it is possible to reduce the load of the temperature raising circulation mechanism that raises the temperature of the indoor gas in the drying chamber.
Furthermore, the outside air introduced into the drying chamber from the input port and the discharge port can be further heated, and the amount of heat transferred between the room gas and the introduced outside air can be further suppressed.
Furthermore, it is possible to further reduce the load of the temperature raising circulation mechanism that raises the temperature of the indoor gas in the drying chamber.
Furthermore, the energy efficiency of the entire drying equipment can be improved by using the heat contained in the dry exhaust gas to raise the temperature of the outside air.

It is a block diagram which shows the drying equipment provided with the continuous box type dryer of this invention. It is the perspective view and longitudinal cross-sectional side view which show the vicinity of the inlet in a continuous box type dryer. It is the front view and side view which show the insertion port vicinity in the continuous box-type dryer provided with the some conveying apparatus. It is a block diagram which shows the reference example similar to the drying equipment with which the continuous box-type dryer of this invention was provided. It is a block diagram which shows the drying equipment with which the conventional continuous box type dryer was provided.

  The form of the drying equipment provided with the continuous box-type dryer of the present invention is as shown in the following examples as an example, but this embodiment is appropriately changed within the scope of the technical idea of the present invention. It is also possible to add.

The drying facility S (hereinafter referred to as the drying facility S) provided with the continuous box dryer 1 of the present invention is, for example, an outer wall material, a plate material such as a gypsum board, or a workpiece B such as a long wire rod. An apparatus for performing a drying process. As shown in FIG. 1, the configuration of the continuous box dryer 1 and the indoor gas G5 in the drying chamber 10 of the continuous box dryer 1 are taken out of the drying chamber 10 and the temperature is raised. Then, the temperature rise circulation mechanism 3 is configured to return the circulation gas G3 to the drying chamber 10, and the air supply mechanism for supplying the outside air G0 for ventilation into the drying chamber 10. 2 is provided as a main element.
Hereinafter, the configuration of the drying facility S will be described in detail while describing the components of the drying facility S.

  First, the continuous box dryer 1 includes a drying chamber 10 in which the inlet 11 and the outlet 12 of the workpiece B are formed in an open state, and the outlet 11 passing through the drying chamber 10 from the inlet 11. 12 is provided with a conveying device 13 such as a belt conveyor, so that continuous processing of a long workpiece B entering the drying chamber 10 from the charging port 11 while being placed on the conveying device 13 is performed. Is a dryer configured to be possible. 1 and 2 show the state in which the end of the transfer device 13 protrudes from the input port 11 and the discharge port 12, but the end of the transfer device 13 protrudes from the input port 11 and the discharge port 12. It is good also as a state which does not.

  In the drying chamber 10, a circulation air supply port 14 is formed at a plurality of upper locations (three locations as an example), and a circulation exhaust port 15 is formed at a plurality of lower locations (three locations as an example). Further, exhaust ports 16 are formed at a plurality of locations (two locations as an example) in the upper portion of the drying chamber 10.

Next, as an example, the air supply mechanism 2 includes a heat pump unit 20, and the heat pump unit 20 includes an evaporator 21, an expansion valve 22, a condenser 23, and a compressor 24. A heat pump cycle is formed, and one using carbon dioxide as a refrigerant is adopted as an example. In addition, by adopting carbon dioxide as the refrigerant, the temperature of the outside air G0 heated by the heat pump unit 20 can be increased. Incidentally, at present, the heat pump unit 20 using carbon dioxide as a refrigerant is put into practical use. However, when the heat pump unit 20 having the same performance using other refrigerants is put into practical use in the future, this is adopted. You can also.
The evaporator 21 is circulated and supplied with hot water stored in a tank 25, and is provided with a circulation pump 26 for this purpose.
Further, a pushing fan 27 for supplying the outside air G0 to the nozzle 5 through the condenser 23 is provided. The nozzle 5 will be described in detail later.
Incidentally, it is also possible to use a heat exchanger instead of the heat pump unit 20 and raise the temperature of the outside air G0 using steam or exhaust hot water.

Next, the temperature raising circulation mechanism 3 is an example in which a hot stove 30 is applied as a temperature raising mechanism. The hot stove 30 raises the temperature of the regeneration gas G6 that is discharged from the drying chamber 10 and humidity. Is a mechanism for returning the circulating gas G3 to the drying chamber 10.
It should be noted that instead of the hot stove 30, the regeneration gas G6 may be heated using an electric heater or a heat exchanger.

The continuous box dryer 1, the air supply mechanism 2, and the temperature raising and circulation mechanism 3 are connected by appropriate pipes to form the drying equipment S. As shown in FIG. The circulation air supply port 14 and the circulation exhaust port 15 of the drying chamber 10 in the type dryer 1 are connected by a pipe line, and a hot stove 30 and a circulation fan 31 are provided to the pipe line.
Further, a nozzle 5 is provided in the vicinity of the inlet 11 and outlet 12 of the drying chamber 10 in the continuous box dryer 1 so that the nozzle 50 faces the nozzle 5. The outside air G0 (temperature rising outside air G1, high temperature outside air G2) heated by the condenser 23 is supplied through the duct 51 by the pushing fan 27.
By adopting such a configuration, the temperature of the outside air G0 is raised to within ± 80 ° C., preferably within ± 50 ° C., more preferably within ± 30 ° C. with respect to the temperature of the indoor gas G5 in the drying chamber 10. The heated outside air G1 or the high temperature outside air G2 can be jetted from the outside of the drying chamber 10 toward the inlet 11 and the outlet 12 from the outside of the drying chamber 10.

Further, in the embodiment shown in FIG. 1, the temperature raising mechanism 6 for further raising the temperature of the heated outside air G1, which is the outside air G0 heated by the air supply mechanism 2 (heat pump unit 20), to the high temperature outside air G2. In this embodiment, a heat pipe 61 is employed as the temperature raising mechanism 6. The heat pipe 61 is a pipe 61a made of a material having high thermal conductivity, in which a volatile liquid (hydraulic fluid) is sealed. A heat absorbing element 61b is provided at one end of the pipe 61a, and a heat radiating element is provided at the other end. By providing 61c, a member capable of transferring heat by generating a cycle of evaporation of the hydraulic fluid (absorption of latent heat) by the heat absorption element 61b and condensation of the hydraulic fluid (release of latent heat) by the heat dissipation element 61c. is there.
In the drying equipment S shown in this embodiment, a heat dissipating element 61 c is provided in a pipe line reaching the nozzle 5 through the condenser 23 in the heat pump unit 20, and a heat absorbing element is provided in a pipe line connected to the exhaust port 16 of the drying chamber 10. 61b was provided. And by adopting such a configuration, the heat in the dry exhaust gas G7 is taken into the temperature rising outside air G1 through the working fluid, and the temperature is raised to obtain the high temperature outside air G2.
The heat pipe 61 functions as the temperature raising mechanism 6. In particular, the heat absorption element 61b substantially functions as the exhaust heat recovery mechanism 7 described below.

Furthermore, in this embodiment, there is provided an exhaust heat recovery mechanism 7 configured so that heat in the dry exhaust gas G7 exhausted from the drying chamber 10 can be taken into the outside air G0 before being input to the drying chamber 10. As an example, a plate fin type heat exchanger 71 is applied.
The heat exchanger 71 is provided in a path of hot water that is circulated and supplied to the evaporator 21 in the heat pump unit 20, and heat in the dry exhaust gas G7 is taken into the hot water.

The drying equipment S of the present invention is configured as described above as an example, and the operation mode thereof will be described below.
First, the pushing fan 27, the heat pump unit 20, the circulation fan 31, the hot stove 30 and the exhaust fan 19 are activated prior to the introduction of the workpiece B, and the outside air G0 taken in by the pushing fan 27 is converted into the heat pump unit. The temperature is raised by the temperature 20 and becomes the temperature rise outside air G1.
Next, the temperature rise outside air G1 is further heated by the heat pipe 61 to become high temperature outside air G2.
Next, the high-temperature outside air G <b> 2 is jetted from the nozzle 5 toward the charging port 11 and the discharging port 12, and is introduced into the drying chamber 10 from the charging port 11 and the discharging port 12.
In the drying chamber 10, the indoor gas G <b> 5 is constituted by the circulating gas G <b> 3 and the high temperature outside air G <b> 2 supplied from the hot stove 30 to the drying chamber 10.
Next, the indoor gas G5 is sent as a regeneration gas G6 from the circulation exhaust port 15 to the hot stove 30 where it is heated and becomes a circulation gas G3 with reduced humidity.
Next, the circulating gas G3 is returned to the drying chamber 10 from the circulating air supply port 14.
Further, the indoor gas G5 is exhausted from the exhaust port 16 as a dry exhaust gas G7, and heat is taken away by the heat absorbing element 61b to become a dry exhaust gas G71 whose temperature is lowered. Further, heat is taken away by the heat exchanger 71 and the temperature is lowered. It becomes dry exhaust gas G72 and is discharged to the outside.

And the to-be-processed object B is thrown in when the state of the drying equipment S is stabilized, An example of the temperature of each gas at the time of steady state is shown below.
Outside air G0: 20 ° C
Temperature rise outside air G1: 80 ° C
High temperature outside air G2: 100 ° C
Circulating gas G3: 150 ° C
Indoor gas G5: 126-150 ° C
Regeneration gas required G6: 126 ° C
Dry exhaust gas G7: 124 ° C
Dry exhaust gas G71: 104 ° C
Dry exhaust gas G72: 70 ° C

In the operation of the drying equipment S as described above, the outside air G0 heated to within ± 80 ° C., preferably within ± 50 ° C., more preferably within ± 30 ° C. with respect to the indoor gas G5 in the drying chamber 10. A certain high temperature outside air G2 is jetted from the outside of the drying chamber 10 toward the input port 11 and the discharge port 12, and this high temperature outside air G2 is introduced into the drying chamber 10. For this reason, while preventing the indoor gas G5 from leaking by the high temperature outside air G2, the amount of heat transferred from the room gas G5 to the high temperature outside air G2 can be suppressed. Furthermore, the energy efficiency of the entire drying equipment S can be improved.
Further, the air supply mechanism 2 includes a heat pump unit 20, and the heat pump unit 20 changes the outside air G0 to the temperature rising outside air G1, thereby reducing the energy cost required to raise the temperature of the outside air G0. be able to. Further, it is possible to reduce the load on the temperature increasing circulation mechanism 3 that raises the temperature of the indoor gas G5 (regeneration gas G6) in the drying chamber 10.
Furthermore, since the air supply mechanism 2 includes a temperature raising mechanism 6 for further raising the temperature of the outside air G0 (temperature rising outside air G1) heated by the heat pump unit 20, the temperature of the outside air G0 is further increased. High temperature outside air G2 can be obtained. And since this high temperature outside air G2 is introduce | transduced in the drying chamber 10 from the inlet 11 and the discharge port 12, the amount of movement of the heat between the indoor gas G5 and the high temperature outside air G2 can be suppressed further.
Further, it is possible to further reduce the load of the temperature raising circulation mechanism 3 that raises the temperature of the indoor gas G5 (regeneration gas G6) in the drying chamber 10.
Further, there is provided an exhaust heat recovery mechanism 7 configured so that heat of G7 in the exhaust gas exhausted from the drying chamber 10 can be taken into the heated outside air G1 or the high temperature outside air G2 before being input to the drying chamber 10. Therefore, the energy efficiency of the drying equipment S as a whole can be improved by using the heat contained in the dry exhaust gas G7 to raise the temperature of the outside air G0.

When both the drying equipment S ′ shown in FIG. 5 and the drying equipment S of the present invention shown in FIG. 1 are operated under the same conditions (dry product amount 1443 kg / h, moisture evaporation 557 kg / h), In the drying equipment S of the invention, it is confirmed that although the heat pump unit 20 and the circulation pump 26 require electric power, the fuel (LP gas) required in the hot stove 30 can be reduced by 28 kg per hour. As a result, when operating for 6000 hours per year, the CO ₂ emission reduction amount was 361 tons per year, and the running cost reduction amount was 11.16 million yen per year.

  Although FIG. 1 shows an embodiment of the continuous box dryer 1 having only one transport device 13, the continuous box dryer 1 is assumed to have a transport device 13 provided in multiple stages. A plurality of objects to be processed B can be simultaneously dried. In the embodiment shown in FIG. 3, the conveying device 13 is provided in five stages, and the nozzles 5 are provided with the nozzles 50 facing the respective inlets 11 and outlets 12. .

[Reference Example] (See Fig. 4)
Here, a reference example similar to the drying equipment S of the present invention will be described. As shown in FIG. 4, the drying equipment S <b> 2 shown in this reference example is configured to supply the high temperature outside air G <b> 2 to the hot stove 30 through the circulation fan 31 without providing the nozzle 5 in the embodiment shown in FIG. 1. It is a thing.
An example of the temperature of each gas in this case is shown below.
Outside air G0: 20 ° C
Temperature rise outside air G1: 80 ° C
High temperature outside air G2: 100 ° C
Circulating gas G3: 150 ° C
Indoor gas G5: 122-150 ° C
Regeneration gas required G6: 122 ° C
Mixed gas G26: 120 ° C
Dry exhaust gas G7: 120 ° C
Dry exhaust gas G71: 100 ° C
Dry exhaust gas G72: 70 ° C

When both the drying equipment S ′ shown in FIG. 5 and the drying equipment S2 as the reference example shown in FIG. 4 are operated under the same conditions, the heat pump unit 20 and the circulation pump 26 require electric power in the drying equipment S2. However, it has been confirmed that the fuel (LP gas) required in the hot stove 30 can be reduced by 16 kg per hour. As a result, when operating for 6000 hours per year, the CO ₂ emission reduction amount was 173 tons per year, and the running cost reduction amount was 55.3 million yen per year.

DESCRIPTION OF SYMBOLS S Drying equipment S2 Drying equipment 1 Continuous box dryer 10 Drying chamber 11 Input port 12 Discharge port 13 Conveying device 14 Circulating air supply port 15 Circulating exhaust port 16 Exhaust port 19 Exhaust fan 2 Air supply mechanism 20 Heat pump unit 21 Evaporator DESCRIPTION OF SYMBOLS 22 Expansion valve 23 Condenser 24 Compressor 25 Tank 26 Circulation pump 27 Pushing fan 3 Temperature rising circulation mechanism 30 Hot air furnace 31 Circulation fan 5 Nozzle 50 Outlet 51 Duct 6 Temperature rising mechanism 61 Heat pipe 61a Pipe 61b Heat absorption element 61c Heat dissipation element 7 Waste heat recovery mechanism 71 Heat exchanger B Processed object G0 Outside air G1 Temperature rising outside air G2 High temperature outside air G26 Mixed gas G3 Circulating gas G5 Indoor gas G6 Regeneration gas G7 Drying exhaust gas G71 Drying exhaust gas G72 Dry exhaust gas

Claims (1)

A long processing object is provided by including a drying chamber in which the inlet and outlet of the object to be processed are formed in an open state, and a transfer device that passes from the inlet to the outlet through the drying chamber. In a drying facility equipped with a continuous box dryer configured to be capable of continuous processing of
In this facility, the indoor gas in the drying chamber in the continuous box dryer is taken out of the drying chamber and heated to a circulating gas, and then the circulating gas is returned to the drying chamber. A heating circulation mechanism;
And an air supply mechanism for supplying outside air for ventilation into the drying chamber.
The air supply mechanism comprises a heat pump unit for raising the temperature of the outside air to make the temperature rise outside air,
The temperature rising outside air is further provided with a temperature raising mechanism for raising the temperature to outside temperature.
This temperature raising mechanism comprises an endothermic element for depriving the heat in the dry exhaust gas exhausted from the drying chamber, and a heat radiating element for releasing this heat into the temperature rising gas,
Furthermore, an exhaust heat recovery mechanism comprising a heat exchanger for taking in the heat in the dry exhaust gas into hot water circulated and supplied to the evaporator in the heat pump unit is provided,
From the dried exhaust gas exhausted from the drying chamber, heat is recovered by the heat absorbing element in the temperature raising mechanism,
Subsequently, in the heat exchanger in the exhaust heat recovery mechanism, heat is recovered from the dry exhaust gas into warm water,
With the heat recovered in this warm water, the temperature of the outside air is raised in the evaporator in the heat pump unit to increase the temperature of the outside air,
Subsequently, the heated outside air is heated to within ± 80 ° C. with respect to the temperature of the indoor gas in the drying chamber by the heat recovered by the endothermic element to be a high temperature outside air,
There is provided a continuous box-type dryer characterized in that the high-temperature outside air is jetted from the outside of the drying chamber to the inlet and outlet, and can be introduced into the drying chamber. Drying equipment.

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