JP6592818B2 - High temperature hot air dryer - Google Patents

Description

  The present invention relates to a high-temperature hot air drying apparatus using air cycle cooling. In particular, it is suitable for drying foods, pharmaceuticals, marine products and the like that need to be cooled immediately after drying with hot air.

  When drying foods, pharmaceuticals, marine products, etc., it is known that it is desirable to dry with hot air and immediately cool to prevent deterioration. To do so, hot air is generated for drying. There is a need for a device and a cooling device for cooling.

  In order to generate such hot air for drying, it is necessary to heat air, and an electric heater, a steam heater, or the like is used as the air heating source.

  In addition, an apparatus that generates hot air using a heat source that constitutes a heat pump cycle that uses alternative chlorofluorocarbon or CO2 as a refrigerant without using the electric heater or the steam heater is also known.

  In addition, an air conditioner using cooling and exhaust heat by an air cycle as a heat source has been proposed (see Patent Document 1).

JP 2000-304449 A

  A device that generates hot air using a heat source that constitutes a CO2 heat pump cycle cannot obtain high-temperature hot air of 120 ° C. or higher, and a device that obtains high-temperature hot air with a conventional electric heater increases power consumption. And in the technique of patent document 1, temperature is low and is unsuitable for the drying using the said hot air. Further, for hot air drying, it is necessary to stably generate high-temperature air without being affected by, for example, the outside air temperature.

  In addition to stably generating high-temperature air suitable for drying using hot air, the present invention provides a high-temperature drying apparatus that can operate with less power by simultaneously operating a heating function and a cooling function with one apparatus. The purpose is to do.

The invention according to claim 1 is provided between the compressor, the expander, and the compressor and the expander, and allows air from the outlet portion of the compressor to flow as first air to the inlet portion of the expander. An air cycle type cooling device comprising a first air passage and an air-to-air heat exchanger having a second air passage that allows outside air to flow as second air, and guides the second air to the drying chamber. A high-temperature hot air drying apparatus used for drying, wherein the first inlet passage is connected to an inlet portion of the compressor and guides outside air to the compressor, and is connected to an outlet portion of the expander from an outlet portion of the expander. A first outlet passage for exhausting the air, a second inlet passage connected to the upstream end of the second air passage portion and introducing outside air to the second air passage portion, and a downstream end of the second air passage portion. A second outlet passage connected to guide the second air to the chamber to be dried; A mixing means provided in the mouth passage; a diversion means provided in the second outlet passage; and a diversion passage connecting the diversion means and the mixing means; and the second outlet passage by the diversion means. A part of the air flowing through is supplied to the mixing means through the branch passage, mixed with outside air in the mixing means, and supplied to the compressor as heated air.

  According to this configuration, a portion of the second air that has absorbed heat in the second air passage portion of the air-to-air heat exchanger and has reached a high temperature is supplied to the mixing means and mixed with the outside air, and has a higher temperature than the outside air. Heated air is supplied to the compressor, and hotter air heated by compression is sent to the first air passage portion of the air-to-air heat exchanger. Therefore, the 2nd air of the 2nd air passage part heat-exchanged with the 1st air of the 1st air passage part becomes high temperature suitable for hot air drying, is sent to a drying room, and is used effectively for drying.

  At this time, since the amount of the high-temperature second air sent to the mixing means through the flow dividing passage can be controlled by controlling the flow dividing means, even if the outside air temperature changes, the mixing means can apply a constant temperature. It can be warm air. Therefore, the temperature of the air discharged from the compressor is also constant, and the temperature of the high-temperature second air used for drying can be controlled to a constant temperature, so that high-temperature air suitable for drying using hot air can be stably generated. It becomes possible, and stable hot air drying can be realized.

  As described above, since the driving force consumed by the compressor can be recovered by the expander by using the air cycle type cooling device, it can be operated with less electric power. Moreover, since cooling immediately after drying is possible with the cold air generated at the same time, the system efficiency can be further improved if it is used for such cooling. Since the heating function and the cooling function can be simultaneously actuated by one apparatus, it is possible to operate with less electric power.

  In this case, as described in claim 2, the first damper is an inlet damper provided on the upstream side of the mixing unit, and the first inlet channel is provided on the downstream side of the mixing unit. A compressor inlet temperature sensor; and a first outside air inflow control means linked to the compressor inlet temperature sensor and the inlet damper, wherein the first outside air inflow control means is provided by the compressor inlet temperature sensor. When the detected temperature is lower than the set temperature, the inlet damper is controlled in a direction in which the opening degree of the inlet damper is reduced, and when the detected temperature is higher than the set temperature, the inlet damper is controlled in a direction in which the opening degree of the inlet damper is increased. It is desirable to have a configuration. Here, the “set temperature” is a predetermined temperature that is set in advance according to the required content of the room to be dried.

  In this way, the opening degree of the inlet damper is controlled according to the compressor inlet temperature detected by the compressor inlet temperature sensor, and the opening degree of the inlet damper is controlled in the direction in which the compressor inlet temperature is maintained at the set temperature. Is done. Thereby, the mixing ratio of the outside air in the mixing means is controlled so that the compressor inlet temperature maintains the set temperature.

  The compressor inlet pressure sensor may be further provided on the downstream side of the mixing unit in the first inlet passage, and the first outside air inflow amount control unit may include the compressor inlet pressure. It is also linked to a sensor, and when the pressure detected by the compressor inlet pressure sensor is larger than a set pressure, the opening degree of the inlet damper is increased, and when the pressure is smaller than the set pressure, the inlet damper is opened. It is desirable that each of the inlet dampers is controlled in the direction of decreasing the degree.

  If it does in this way, the opening degree of an entrance damper can be controlled and the extra load concerning a compressor can be controlled.

5. The apparatus according to claim 4, further comprising second outside air inflow control means linked to the compressor inlet temperature sensor and the diversion means, wherein the second outside air inflow control means is the compressor inlet temperature sensor. When the detected temperature is lower than the set temperature, the flow rate of the second air flowing through the diversion passage is increased. When the temperature is higher than the set temperature, the flow rate of the second air flowing through the diversion passage is decreased. It is desirable to adopt a configuration that controls the flow dividing means.

  If it does in this way, the amount of 2nd air mixing in a mixing means will be controlled by controlling a diversion means according to compressor inlet temperature, and it will be controlled in the direction where compressor inlet temperature maintains preset temperature. .

According to a fifth aspect of the present invention, the second outside air inflow control means is also linked to the compressor inlet pressure sensor, and when the pressure detected by the compressor inlet pressure sensor is larger than the set pressure, It is desirable that the diversion unit be controlled in a direction to increase the flow rate of the second air flowing through the diversion passage .

  If it does in this way, a diversion means can be controlled and the extra load concerning a compressor can be controlled.

  The air passage portion of the first air-to-water heat exchanger is disposed between the first air passage portion of the air-to-air heat exchanger and the inlet portion of the expander. It can also be set as the structure.

  If it does in this way, cooler air can be obtained using the cooling water by the 1st air to water heat exchanger.

  According to a seventh aspect of the present invention, the air passage portion of the second air-to-water heat exchanger can be arranged downstream of the diversion means in the second outlet passage.

  If it does in this way, the supply water by a 2nd air-to-water heat exchanger can be heated using high temperature 2nd air, and it can utilize as warm water.

  The first passage portion of the exhaust heat recovery heat exchanger is disposed in the exhaust duct from the drying chamber, and the second passage portion of the exhaust heat recovery heat exchanger is connected to the first inlet. It can be set as the structure arrange | positioned in the channel | path.

  In this way, exhaust heat can be recovered to the outside air introduced from the first inlet passage using the exhaust heat recovery heat exchanger, and thus the temperature of the outside air can be efficiently increased.

  According to the present invention, by controlling the diverting means and adjusting the mixing amount of the high-temperature second air sent to the mixing means through the diversion passage, even if the outside air temperature changes, the mixing means can make the air at a constant temperature. As a result, the temperature of the air discharged from the compressor can be kept constant, the temperature of the high-temperature second air that is sent to the drying chamber and used for drying can be easily controlled to a constant temperature, and a stable high temperature Hot air drying can be realized.

  In addition, by using the function to generate high-temperature air stably and to generate the cold air that the air cycle type cooling device originally has, the heating function and the cooling function can be operated simultaneously with one device. Therefore, it is possible to operate with less electric power and to save energy.

It is a figure which shows schematic structure of the high temperature hot air drying apparatus using the air cycle type cooling which is Embodiment 1 of this invention. It is a block diagram which shows the control system of the high temperature hot air drying apparatus of the said Embodiment 1. It is a figure which shows schematic structure of the high temperature hot air drying apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows schematic structure of the high temperature hot air drying apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the application example using the said high temperature hot air drying apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 shows an example of equipment arrangement of a high-temperature drying apparatus using air cycle cooling which is an embodiment of the present invention.

  The high-temperature drying apparatus has a first system S1 that is an air cycle cooling circuit and a second system S2 that is a hot air generation circuit.

  The first system S1 is configured by connecting the compressor 21, the air-to-air heat exchanger 30, and the expander 22 in order, and constitutes an air cooling cycle circuit that performs an air cooling cycle operation.

  The first system S1 includes a first inlet passage 23 that takes air (outside air) into the compressor 21 and a first outlet passage 24 that discharges air from the expander 22, and is in the middle of the first inlet passage 23. Further, a mixer 50 (mixing means) and a dehumidifier 55 are arranged in the middle of the first outlet passage 24.

  On the other hand, the second system S2 includes a blower 45 that blows outside air to the air-to-air heat exchanger 30 as second air, and a diversion valve 22 (diversion means) that diverts the high-temperature second air from the heat exchanger 30. Have The second inlet passage 23 provided with the blower 45 is provided on the second air inlet side of the heat exchanger 30, and the second outlet passage 24 provided with the diversion valve 44 is provided on the second side of the heat exchanger 30. Each is connected to the air outlet side.

  The diversion valve 44 supplies a part of the hot second air from the heat exchanger 30 to the mixer 50 through the diversion passage 43. The mixer 50 serves to increase the temperature of air supplied to the compressor 21 by mixing outside air and high-temperature second air. On the other hand, the remaining portion of the high-temperature second air is configured to be guided to a drying chamber (heating chamber) (not shown) through the second outlet passage 42. And in the said drying chamber, hot-air drying using high temperature air is performed.

  A high speed motor 28 is connected to the compressor 21 and is also connected to the expander 22. The compressor 21 is driven by the driving force of the high-speed motor 28 and the expansion work when air expands in the expander 22.

  The air-to-air heat exchanger 30 is partitioned into a first air passage portion 31 (a high pressure heat radiation side passage of the first system S1) and a second air passage portion 32 (a low pressure heat absorption side passage of the second system S2). ing. One end of the first air passage portion 31 is connected to the compressor 21 and the other end is connected to the expander 22, and the first air flows inside. A second inlet passage 41 having a blower 45 in the middle is connected to one end of the second air passage portion 32, and a second outlet passage 42 having a diversion valve 44 in the middle is connected to the other end, and the second air passes through the inside. Flowing. The air-to-air heat exchanger 30 is configured to exchange heat between the first air in the first air passage portion 31 and the second air in the second air passage portion 32, thereby heating the second air. Has been. Therefore, the outside air is taken in through the second inlet passage 41 by the blower 45 and blown to the second air passage portion 32 of the heat exchanger 30, whereby second air of high-temperature air can be obtained.

  The dehumidifier 55 serves to remove moisture and the like contained in the low temperature first air from the expander 22, and the low temperature first air is supplied to the dehumidifier 55 through the first outlet passage 24 connected to the dehumidifier 55, for example. It can be led to the cooling room and used for cooling.

  The first inlet passage 23 is provided with an inlet damper 25 on the upstream side of the mixer 50, and the first outside air temperature sensor 1 is provided on the upstream side of the first damper 25. A compressor inlet temperature sensor 2 and a compressor inlet pressure sensor 3 are sequentially provided on the downstream side of the mixer 50. The first outlet passage 24 is provided with the cooling air temperature sensor 4 on the downstream side of the dehumidifier 55.

  The second outside air temperature sensor 5 is provided on the upstream side of the blower 45, and the high temperature air temperature sensor 6 is provided on the second outlet passage 42 on the upstream side of the flow dividing valve 44.

  Next, control by the control system of the apparatus will be described in detail with reference to FIG.

  The high speed motor 28 is driven and controlled by the high speed motor rotation speed selection means 10, and the blower 45 is driven and controlled by the blower rotation speed selection means 11. The high-speed motor rotation speed selection means 10 and the blower rotation speed selection means 11 depend on the temperature detected by the first and second outside air temperature sensors 1 and 5 and the conditions required in the drying chamber and / or the cooling chamber. Thus, a preset rotation speed is selected, and the high-speed motor 28 and the blower 45 are rotated at the rotation speed. In other words, the rotation speed of the high-speed motor 28 and the blower 45 is preset on the map according to the outside air temperature and the conditions required in the room to be dried and / or the room to be cooled. Although the selected number of rotations is selected from the map, it may be performed manually.

  The compressor inlet temperature sensor 2 and the inlet damper 25 are linked to the first outside air inflow control means 12, and the first outside air inflow control means 12 responds to the compressor inlet temperature detected by the compressor inlet temperature sensor 2. Thus, the opening degree of the first damper 25 is adjusted. That is, when the compressor inlet temperature detected by the compressor inlet temperature sensor 2 is lower than the set temperature (a predetermined temperature that is preset according to the content of the room to be dried), the opening degree of the inlet damper 25 is The inlet damper 25 is controlled in the decreasing direction, the first inlet passage 23 is throttled, and the amount of outside air inflow is reduced. Thereby, the mixing ratio of the outside air having a low temperature in the mixer 50 is reduced, and the compressor inlet temperature is controlled to be high. On the other hand, when the compressor inlet temperature is higher than the set temperature, the inlet damper 25 is controlled in the direction in which the opening degree of the inlet damper 25 is increased, the first inlet passage 23 is widened, and the outside air inflow amount is increased. To be. Accordingly, the mixing ratio of the outside air having a low temperature in the mixer 50 is increased, and the compressor inlet temperature is controlled to be low.

The compressor inlet temperature sensor 3 and the diversion valve 44 are linked to the second outside air inflow control means 13, and when the compressor inlet temperature detected by the compressor inlet temperature sensor 3 is lower than the set temperature, the diversion passage 43. On the other hand, when the compressor inlet temperature is higher than the set temperature, the flow rate of the high temperature second air flowing through the flow dividing passage 43 is decreased. The diversion valve 44 is controlled.

Thus, the first outside air inflow control means 12 and the second outside air inflow control means 13 allow the opening degree of the inlet damper 25 and the flow rate of the high-temperature second air flowing through the diversion passage 43 to be the same as the inlet temperature of the compressor 21. Since it is controlled to be maintained at the set temperature, the inlet temperature of the compressor 21 is maintained within a certain temperature range including the set temperature, and as a result, the outlet temperature of the compressor 21 is also maintained within the certain temperature range. .

The first outside air inflow control means 12 and the second outside air inflow control means 13 are also linked to the compressor inlet pressure sensor 3, and the compressor inlet pressure detected by the compressor inlet pressure sensor 3 is set pressure ( If the value is larger than the set value permitted by the compressor performance), the inlet damper 25 is controlled in the direction in which the opening degree of the inlet damper 25 increases, and the flow rate of the second air flowing through the diversion passage 43 is increased. Thus, the flow dividing valve 44 is controlled. As a result, a large amount of the second air flows into the mixer 50, the compressor inlet pressure is controlled in a direction approaching the set pressure, and the suction resistance of the compressor 21 is reduced. Here, since the amount of suction of the compressor 21 is determined by the number of rotations, since the second air more than that is pressurized by the blower 45, it escapes from the open inlet damper 25 to the outside air side. Become. Since the temperature is higher than the set temperature as it is, the flow rate of the second air flowing through the flow dividing passage 43 is reduced by controlling the flow dividing valve 44, and the compressor inlet pressure approaches the set pressure.

  The first and second outside air temperature sensors 1 and 5 both detect the outside air temperature, but the compressor inlet temperature rises and the second air flows back from the inlet damper 25 in the first inlet passage 23. When this is done, the temperature detected by the first outside air temperature sensor 1 becomes higher than the temperature detected by the second outside air temperature sensor 5. If it continues for a long time, it is considered that the cause is a control failure or the compressor stop, so that the system protection such as stopping the high-speed motor 28 or the blower 45 can be achieved.

  According to the above apparatus, in the first system S <b> 1, the outside air enters the mixer 50 from the first inlet passage 23, and is heated with the high-temperature second air from the second system S <b> 2 taken into the mixer 50. Air is supplied to the compressor 21 as the first air. In the compressor 21, the mixed and heated first air is compressed, the temperature and pressure rise, enter the air-to-air heat exchanger 30, flow through the high pressure heat radiation side passage 31, and the second air in the low pressure heat absorption side passage 32. It is cooled by exchanging heat with it. The cooled first air is expanded by the expander 22, and the temperature and pressure of the first air are reduced. The first air having a low temperature is supplied with moisture to the room to be cooled through the first outlet passage 24 after the moisture is removed by the dehumidifier 55. Further, by utilizing the expansion of air, the expander 22 can recover the driving force of the high-speed motor 28.

  In the second system S2, outside air is taken in as second air from the second inlet passage 23, supplied from the blower 45 to the heat exchanger 30 and flows through the low pressure endothermic side passage 32, and the first air and heat in the high pressure heat dissipation side passage 31 are supplied. Exchange. Due to this heat exchange, the temperature of the second air rises and becomes high temperature, and is diverted into the second outlet passage 24 and the diversion passage 43 by the diversion valve 44. The high-temperature second air that has been diverted to the diversion passage 43 is supplied to the mixer 50, used for heating the first air, and the high-temperature second air that has been diverted to the second outlet passage 24 is It is supplied to the drying chamber and used for drying in the drying chamber.

  Since the diverter valve 44 divides the hot second air from the heat exchanger 30 into a flow to the mixer 50 and a flow through the second outlet passage 24, an amount to be introduced to the mixer 50, a second The flow rate leading from the outlet passage 24 to the drying chamber can be adjusted by the second outside air inflow control means 13. These amounts are automatically controlled and adjusted so that the inlet temperature of the compressor 21 becomes a constant temperature even when the outside air temperature changes. As a result, the outlet temperature of the compressor 21 is maintained at a constant temperature.

  Moreover, since the inlet damper 25 whose opening degree is controlled by the first outside air inflow control means 12 is arranged in the middle of the first inlet passage 23 for taking in outside air, the outside air is taken into the mixer 50. The amount can be adjusted. In addition, the second air heated by the air-to-air heat exchanger 30 is taken into the mixer 50 through the branch passage 43. Then, the compressor 21 is connected by mixing the outside air and the high temperature air of the second air in the mixer 50 equipped with a device for efficiently mixing the air introduced from the two locations, and connecting the remaining hot air at a temperature higher than the outside air temperature. Can be incorporated into.

Thus, according to the said apparatus, a heating function and a cooling function can be made to act simultaneously by one apparatus by utilizing a hot hot air from 2nd system | strain S2 simultaneously with supply of the low temperature cold wind of 1st system | strain S1. Because it can, it can be operated with less power.
(Embodiment 2)
As shown in FIG. 3, in the apparatus (basic system) shown in FIG. 1, the first air-to-water heat is provided between the first air passage portion 31 of the air-to-air heat exchanger 30 and the inlet portion of the expander 22. The air passage portion of the exchanger 35 can be arranged to obtain cooler air.

In the air-to-air heat exchanger 30 in FIG. 1, the temperature of the first air cooled by the second air of the outside air does not become lower than the outside air temperature, so that there is a limit to the temperature that is lowered by the expander 22. Therefore, the first air entering the expander 22 by arranging the air passage portion of the air-to-water heat exchanger 31 between the first air passage portion 31 of the air-to-air heat exchanger 30 and the inlet portion of the expander 22. Is cooled by the cooling water 36. Thereby, it can be made lower than the exit temperature of the expander 22. Further, by adjusting the cooling water temperature (flow rate), the temperature of the low-temperature cold air from the expander 22 is adjusted while keeping the outlet temperature of the compressor 21 constant (that is, keeping the hot air temperature of the second system S2 constant). Since it can be adjusted, it can be used for various purposes (cooling, refrigeration, freezing, etc.).
(Embodiment 3)
Embodiment 3 of FIG. 4 is a modification of the apparatus shown in FIG. 3, and further, the air of the second air-to-water heat exchanger 60 is downstream of the diversion means 44 in the second outlet passage 42 of the second system S2. The passage portion is arranged, and the supply water 65 is heated using high-temperature second air and used as hot water.

It is also possible to use hot air held in the second air from the second outlet passage 42 depending on the amount of heat exchange between the supply water 65 and the second air.
(Embodiment 4)
FIG. 5 shows an application example of the apparatus shown in FIG. The supply source of the high-temperature hot air of the second air generated simultaneously with the low-temperature cold air of the first air is the horizontal continuous fluidized bed drying apparatus 70 (the room to be dried), and the high-temperature hot air of the air is used for drying. A first passage portion of the exhaust heat recovery heat exchanger 80 is disposed in the exhaust duct 71 from the horizontal continuous fluidized bed drying device 70, and a second passage portion of the exhaust heat recovery heat exchanger 80 is disposed in the first inlet passage 23. ing. The supply source of the low-temperature cold air of the first air is the horizontal continuous fluidized bed cooling device 75 (cooled chamber).

  Since exhaust heat can be recovered to the outside air introduced from the first inlet passage 23 using the exhaust heat recovery heat exchanger 80, the temperature of the outside air can be efficiently increased.

  Conventionally, a hot air generator (heater or the like) that generates high-temperature hot air for drying and a cooling device that generates low-temperature cold air for cooling are required. Since air for cooling and air for cooling can be generated, a space saving effect and an energy saving effect can be obtained together.

S1 1st system (air cycle cooling circuit)
S2 Second system (hot air generation circuit)
DESCRIPTION OF SYMBOLS 1 1st outside temperature sensor 2 Compressor inlet temperature sensor 3 Compressor inlet pressure sensor 4 Cooling air temperature sensor 5 Second outside air temperature sensor 6 2nd high temperature air temperature sensor 10 High-speed motor rotation speed selection means 11 Blower rotation speed selection means 12 First outside air inflow control means 13 Second outside air inflow control means 21 Compressor 22 Expander 23 First inlet passage 24 First outlet passage 25 Inlet damper 28 High-speed motor 30 Air-to-air heat exchanger 31 High-pressure heat radiation side passage 32 Low pressure endothermic side passage 35 First air-to-water heat exchanger 36 Cooling water 41 Second inlet passage 42 Second outlet passage 43 Dividing passage 44 Dividing valve (dividing means)
45 Blower 50 Mixer (mixing means)
55 Dehumidifier 60 Second air-to-water heat exchanger 65 Supply water 70 Horizontal continuous fluidized bed drying device 71 Exhaust duct 75 Horizontal continuous fluidized bed cooling device 80 Exhaust heat recovery heat exchanger

Claims (8)

A compressor, an expander, a first air passage portion provided between the compressor and the expander, and air flowing from the outlet portion of the compressor as first air to the inlet portion of the expander and the outside air High-temperature hot-air drying having an air-cycle type cooling device including an air-to-air heat exchanger having a second air passage portion for flowing air as second air, and leading the second air to a drying chamber and using it for drying A device,
A first inlet passage connected to an inlet of the compressor and leading outside air to the compressor;
A first outlet passage connected to an outlet portion of the expander and exhausting air from the outlet portion of the expander;
A second inlet passage connected to the upstream end of the second air passage portion for introducing outside air into the second air passage portion;
A second outlet passage connected to a downstream end of the second air passage portion and guiding the second air to the drying chamber;
Mixing means provided in the first inlet passage;
A diversion means provided in the second outlet passage;
A diversion passage connecting the diversion means and the mixing means,
A part of the air flowing through the second outlet passage by the diversion means is supplied to the mixing means through the diversion passage, mixed with outside air in the mixing means, and supplied to the compressor as warm air; A high-temperature hot-air drying apparatus characterized by being made. An inlet damper provided on the upstream side of the mixing means in the first inlet passage;
A compressor inlet temperature sensor provided in the first inlet passage and downstream of the mixing means;
A first outside air inflow control means linked to the compressor inlet temperature sensor and the inlet damper;
When the temperature detected by the compressor inlet temperature sensor is smaller than a set temperature, the first outside air inflow amount control means decreases the opening degree of the inlet damper, and when the temperature is larger than the set temperature, The high-temperature hot-air drying apparatus according to claim 1, wherein the inlet damper is controlled in a direction in which the opening degree of the inlet damper increases. A compressor inlet pressure sensor provided on the downstream side of the mixing means in the first inlet passage;
The first outside air inflow control means is also linked to the compressor inlet pressure sensor, and when the pressure detected by the compressor inlet pressure sensor is larger than a set pressure, the opening degree of the inlet damper is increased. Furthermore, the high temperature hot air drying apparatus of Claim 2 which controls the said inlet damper in the direction where the opening degree of the said inlet damper becomes small when smaller than the said setting pressure. A second outside air inflow control means linked to the compressor inlet temperature sensor and the diversion means;
When the temperature detected by the compressor inlet temperature sensor is lower than the set temperature, the second outside air inflow control means is higher than the set temperature in a direction to increase the flow rate of the second air flowing through the diversion passage. 4. The high-temperature hot air drying apparatus according to claim 3 , wherein the diversion unit is controlled to reduce the flow rate of the second air flowing through the diversion passage. The second outside air inflow control means is also linked to the compressor inlet pressure sensor, and when the pressure detected by the compressor inlet pressure sensor is larger than the set pressure, the second air flowing in the branch passage. The high-temperature hot-air drying apparatus according to claim 4 , wherein the diverting means is controlled in a direction to increase the flow rate.   The air passage portion of the first air-to-water heat exchanger is disposed between the first air passage portion of the air-to-air heat exchanger and the inlet portion of the expander. The high temperature hot air drying apparatus as described in any one.   The high-temperature hot-air drying apparatus according to any one of claims 1 to 6, wherein an air passage portion of a second air-to-water heat exchanger is disposed downstream of the diversion means in the second outlet passage.   The first passage portion of the exhaust heat recovery heat exchanger is disposed in the exhaust duct from the drying chamber, and the second passage portion of the exhaust heat recovery heat exchanger is disposed in the first inlet passage. The high temperature hot-air drying apparatus as described in any one of 1-6.

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