Drying device

Abstract

[Problem] To provide a drying device capable of shortening the drying time of an object to be dried. [Solution] A drying device 1 according to the present invention comprises: a drying chamber 10 having a drying space S for storing an object to be dried MO; a vacuum pump 30 communicating with the drying space S; a measuring device 15 capable of measuring at least one of the pressure, temperature, and humidity of the drying space S, and temperature of the object to be dried MO; and a control device 60 for reducing the pressure of the drying space S by controlling the vacuum pump 30 on the basis of the measurement result outputted by the measuring device 15.

Description

drying equipment

[0001] The present invention relates to a drying device capable of drying an object to be dried housed in a drying chamber.

[0002] Patent Document 1 discloses a technique in which air heated by an electric heater is supplied to a drying chamber to dry items (for example, clothes) contained in the drying chamber.

[0003] Japanese Patent Application Laid-Open No. 2023-057902

[0004] However, the technology described in Patent Document 1 is configured to blow heated air onto the material to be dried, which contains moisture, to gradually evaporate the moisture, which not only causes uneven drying of the material to be dried, but also inevitably results in a long drying time.

[0005] The present invention provides a drying device capable of shortening the drying time of an object to be dried.

[0006] The drying device of the present invention is characterized by comprising a drying chamber having a drying space for accommodating the material to be dried, a pressure reducing means for reducing the pressure in the drying space, a measuring means capable of measuring at least one of the pressure, temperature, humidity and temperature of the material to be dried in the drying space, and a control means for controlling the pressure reducing means based on the measurement results by the measuring means to reduce the pressure in the drying space.

[0007] Preferably, the drying apparatus further comprises a pressurizing means for pressurizing the drying space, and the control means controls the pressurizing means based on the measurement result by the measurement means to pressurize the drying space.

[0008] In this case, preferably, the control means alternately repeats pressurization and depressurization of the drying space.

[0009] Preferably, the drying apparatus further comprises a heating means for heating the drying space, and the control means controls the heating means to heat the drying space.

[0010] According to the present invention, the drying time of an object to be dried can be shortened even with a relatively simple configuration.

[0011] 1 is a schematic diagram showing an overview of a drying apparatus according to the present embodiment. FIG. 2 is a block diagram showing an overview of the drying apparatus of FIG. 1. FIG. 3 is a flowchart showing an example of control processing in the drying apparatus of FIG. 1. FIG. 4 is a schematic diagram showing an overview of a drying apparatus used in a test for verifying the drying time of an object to be dried. FIG. 5 is a table showing test conditions adopted in a test for verifying the drying time of an object to be dried. FIG. 6 is a graph showing the transition of pressure in a drying chamber when a test was conducted under the test conditions of FIG. 5, where (a) is a diagram showing the pressure in the drying chamber according to Example 1 and (b) is a diagram showing the pressure in the drying chamber according to Example 2. FIG. 7 is a graph showing test results when a test was conducted under the test conditions of FIG. 5. FIG. 8 is a schematic diagram showing an overview of a modified example of the drying apparatus of FIG. 1. FIG. 9 is a schematic diagram showing an overview of a modified example of the drying apparatus of FIG. 8. FIG. 10 is a schematic diagram showing an overview of a further modified example of the drying apparatus of FIG. 1.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used throughout the drawings to avoid repetitive explanation.

[0013] FIG. 1 is a schematic diagram showing an outline of a drying device according to this embodiment, FIG. 2 is a block diagram showing an outline of the drying device of FIG. 1, and FIG. 3 is a flowchart showing an example of a control process in the drying device of FIG.

[0014] <Configuration of Drying Apparatus 1> As shown in Fig. 1, the drying apparatus 1 according to this embodiment is an apparatus capable of drying an object to be dried (MO), and is configured to include a drying chamber 10, a measuring device 15 as a measuring means, a heat pump unit 20, a vacuum pump 30 as a decompression means, a pressurizing mechanism 40 as a pressurizing means, and a control device 60 as a control means. The object to be dried (MO) may be any object containing moisture, and is not limited to clothing as shown in Fig. 1, but may also be, for example, food or medicine. Depending on the type of object to be dried (MO), the rotating drum 11, which will be described later, may be omitted.

[0015] The drying chamber 10 is provided in the drying device main body 2, and has a rotating drum 11 in its internal space (hereinafter referred to as the "drying space S") capable of accommodating the material to be dried MO. The rotating drum 11 is connected to a rotating drum motor 12, and is configured to be rotated in a forward direction (e.g., clockwise) and a reverse direction (e.g., counterclockwise) within the drying chamber 10 by the rotating drum motor 12. The rotating drum motor 12 is driven to rotate in a predetermined direction and at a predetermined rotation speed in accordance with a control signal transmitted from the control device 60.

[0016] The drying chamber 10 is formed with an air outlet 10A for introducing heated air (hereinafter referred to as "heated air") into the drying space S, a first exhaust port 10B for exhausting the heated air from the drying space S, and a second exhaust port 10C to which a vacuum pump 30 is connected via an exhaust pipe 32. The air outlet 10A and the first exhaust port 10B are connected by a circulation air duct 50 for circulating the air in the drying space S.

[0017] As will be explained in more detail, a blower 51 (e.g., a blower fan) and a heat pump unit 20 are installed in this order along the air circulation path 50 from the first exhaust port 10B toward the air outlet 10A. By driving the blower 51, air in the drying space S is exhausted from the first exhaust port 10B, flows through the circulation flow path 50, and then flows back into the drying space S via the air outlet 10A. For ease of explanation, the side of the first exhaust port 10B in the circulation air path 51 will be referred to as the "upstream side," and the side of the air outlet 10A will be referred to as the "downstream side."

[0018] The measuring device 15 according to this embodiment has a pressure sensor 15A and a temperature sensor 15B, which are provided at predetermined positions in the drying space S. The pressure sensor 15A is a sensor that measures the pressure in the drying space S, and the temperature sensor 15B is a sensor that measures the temperature in the drying space S.

[0019] The heat pump device 20 includes a compressor 21 that compresses the refrigerant, a radiator 22 that radiates heat from the compressed high-temperature, high-pressure refrigerant, a throttle valve 23 that reduces the pressure of the high-pressure refrigerant to maintain the pressure difference of the refrigerant, a heat absorber 24 that absorbs heat from the surroundings using the reduced-pressure refrigerant, and a circulation air duct 25 that connects these components so that the refrigerant circulates.

[0020] The radiator 22 and the heat absorber 24 are attached midway along the circulating air passage 51 in a manner that allows the passage of air circulating in the circulating air passage 51. The radiator 22 is disposed between the air outlet 10A of the drying chamber 10 and the downstream side of the heat absorber 24, while the heat absorber 24 is disposed between the first exhaust port 10B of the drying chamber 10 and the upstream side of the radiator 22.

[0021] Therefore, in this embodiment, by driving both the heat pump device 20 and the blower device 51, it is possible to circulate the air present in the drying space S and the circulation air duct 50 in the following order: drying chamber 10 → heat absorber 24 → radiator 22 → drying chamber 10 → heat absorber 24 → radiator 22 → ...

[0022] In other words, in this embodiment, heated air heated by the radiator 22 can be flowed into the drying space S, making it possible to dry the material to be dried MO contained in the rotating drum 11 (drying chamber 10).

[0023] In addition, in this embodiment, the heated air exhausted from the drying chamber 10 is cooled and dehumidified by the heat absorber 24. This reduces the heat (heat generation amount) generated within the drying device 1, thereby preventing the heat from reducing the operating efficiency of various internal devices (for example, the feeding device 51 arranged around the heat absorber 24) or causing breakdowns in the devices.

[0024] However, depending on the heating capacity of the heat radiator 22 and the cooling / dehumidifying capacity of the heat absorber 24, there is a possibility that the heat absorber 24 may not be able to sufficiently cool the air flowing through the circulating air passage 51, and in such a case, the situation described above may occur. Therefore, in this embodiment, from the viewpoint of preventing such a situation, a spare space 52 having a cross-sectional area larger than that of the circulating air passage 51 is arranged between the downstream side of the heat absorber 24 and the upstream side of the heat radiator 22.

[0025] This reduces the flow velocity of the air passing through the reserve space 52, making it possible to temporarily (pseudo) retain the air in the reserve space 52. That is, in this embodiment, the air cooled by the heat absorber 24 can be effectively brought into contact with the air retained in the reserve space 52, making it possible to effectively cool the air in the reserve space 52. As a result, it is possible to effectively reduce the heat generated in the drying device 1, and it is possible to reliably prevent the above-mentioned situation.

[0026] To more reliably prevent the above-described situation, it is preferable to provide a heat-absorption bypass air duct 53 that connects the upstream side of the heat absorber 24 in the circulation air duct 50 with the reserve space 52. In this case, it is more preferable to install a heat-absorption control valve 54 (e.g., an opening adjustment valve (hereinafter referred to as an "electric valve") or an opening adjustment damper (hereinafter referred to as a "motor damper")) midway through the heat-absorption bypass air duct 53 to control the flow rate of air flowing through the air duct, and to install a heat-absorption blower 55 (e.g., a blower fan) to forcibly return air in the reserve space 52 to the circulation air duct 50. With this configuration, air stagnating in the reserve space 52 can be cooled more effectively, thereby more reliably preventing the above-described situation.

[0027] Furthermore, when such a heat-absorbing bypass air duct 53 is provided in the drying device 1, it is possible to omit the spare space 52 from the viewpoint of space saving, etc. In this case, the heat-absorbing bypass air duct 53 may be provided so as to communicate the upstream side and downstream side of the heat absorber 24 in the circulation air duct 50.

[0028] In order to reduce the heat generated in the drying device 1, it is preferable to cover the drying chamber 10, the heat pump device 40, the circulating air duct 50, etc. with a heat insulating material (e.g., glass wool, rock wool).

[0029] Furthermore, in this embodiment, an air passage similar to the heat-absorbing bypass air passage 53 can be provided on the radiator 22 side. As an example of such a configuration, a bypass air passage (heat-radiating bypass air passage 56) equipped with a blower (heat-radiating air blower 58) and a control valve (heat-radiating control valve 57) can be provided so as to connect the upstream side of the radiator 22 in the circulation air passage 50 with the drying chamber 10. With this configuration, the heated air that has flowed into the drying space S can be reheated by the radiator 22, so that the air in the drying space S can be reliably heated, and as a result, the drying efficiency of the material to be dried MO can be further improved.

[0030] Furthermore, in this embodiment, the air introduced into the drying space S is heated using the heat pump device 20 (radiator 22), but it may also be heated using other heating means, for example, an electric heater, or may be heated using a heating source such as gas or steam.

[0031] The vacuum pump 30 is a device for reducing the pressure in the drying space S. The vacuum pump 30 is connected to the second exhaust port 10 of the drying chamber 10 via an exhaust pipe 32. An exhaust control valve 31 capable of closing and opening the exhaust pipe 32 is attached upstream of the vacuum pump 30 via the exhaust pipe 32. The exhaust control valve 31 may be any valve provided with a valve element that is electrically movable between a closed position and an open position, and for example, a solenoid valve (hereinafter simply referred to as a "solenoid valve") or an electrically operated valve that only opens and closes the valve element may be used.

[0032] In this embodiment, the vacuum pump 30 is attached to the drying chamber 10, but instead, it may be attached so as to branch off from the middle of the circulation air duct 50, or it may be attached to the middle of the circulation air duct 50. When the vacuum pump 30 is attached to the middle of the circulation air duct 50, the vacuum pump 30 can have the function of circulating (distributing) the air within the circulation air duct 50 in addition to the function of reducing the pressure in the drying space S. Such a configuration can be realized, for example, by: attaching the vacuum pump 30 instead of the sending device 51; attaching an exhaust pipe 32 so as to branch off from the circulation air duct 50; and connecting an exhaust control valve 31 to the exhaust pipe 32.

[0033] The pressurizing mechanism 40 is a device that pressurizes the drying space S and includes an intake control valve 41 and an intake pipe 42. The intake control valve 41 is a device equipped with a valve body that is electrically movable between a closed position and an open position, and for example, a solenoid valve or an electric valve can be used. The intake pipe 42 is branched and connected to a predetermined position of the circulating air duct 50, and the intake control valve 41 is attached midway through the pipe, and the end of the pipe is disposed in the drying device main body 2 so as to be open to the outside air.

[0034] In this embodiment, when the intake control valve 41 is opened while the drying space S is depressurized, outside air is introduced into the drying space S via the circulating air passage 50. This allows the drying space S, which has been depressurized by the vacuum pump 30, to be pressurized.

[0035] In this embodiment, the pressurizing mechanism 40 is attached to the circulation pipe 50, but this is not limiting and the pressurizing mechanism 40 can also be attached to the drying chamber 10. In this embodiment, the pressure in the drying space S is increased by opening the intake control valve 41, but it can also be increased by, for example, driving a separately provided pressure pump.

[0036] 1 and 2, the control device 60 has a central processing unit 61 and a storage device 62. The control device 60 is electrically connected to various devices, such as the rotary drum motor 12, the heat pump device 20, the vacuum pump 30, the exhaust control valve 31, the intake control valve 41, the air blower 51, the measuring device 15, and the drying time measuring timer 16, via a bus 63.

[0037] The central processing unit 61 is made up of a CPU (Central Processing Unit), and reads various programs stored in the storage device 62 , performs predetermined arithmetic processing, and executes overall control for operating the drying device 1 .

[0038] The storage device 62 is made up of a semiconductor memory such as a ROM (Read Only Memory), and has a storage area for storing programs for operating the drying device 1 and various databases.

[0039] <Control Processing in Drying Apparatus 1> Next, the control processing in the drying apparatus 1 will be described with reference to FIGS.

[0040] As shown in Figures 1 to 3, this control process is mainly executed by the central processing unit 61 of the control device 60, and begins with a process of determining whether or not a start operation has been performed to dry the material to be dried MO in step S101.

[0041] When the central processing unit 61 determines that a start operation for drying the object to be dried MO has been performed (step S101), it performs a process of driving the heat pump unit 20 and the air blower 51 (step S102). As a result, the heated air heated by the radiator 22 is sequentially flowed into the drying space S, making it possible to dry the object to be dried MO.

[0042] Next, the central processing unit 61 starts the drying time measuring timer 16 (step S103). The drying time measuring timer 16 measures the elapsed time from the start of the drying process and is configured to be reset when a predetermined drying time (e.g., 30 minutes, hereinafter referred to as the "predetermined drying time") has elapsed.

[0043] Thereafter, the central processing unit 61 drives the vacuum pump 32 (step S104), and then opens the exhaust control valve 31 (pressure reduction start process) (step S105). This gradually reduces the pressure in the drying space S. In the drying chamber 10, as the pressure in the drying space S is reduced, the boiling point of water decreases (the evaporation rate of water increases), which makes it possible to accelerate the drying of the object to be dried MO.

[0044] Next, when the pressure in the drying space S reaches the lower limit specified value (step S106), the central processing unit 61 closes the exhaust control valve 31 (decompression stop process) (step S107). This makes it possible to prevent an extreme drop in the pressure in the drying space S. Note that the pressure in the drying space S can be measured by the pressure sensor 15A, as described above.

[0045] The reason for performing the above-described steps S106 and S107 will now be explained. Generally, the vapor pressure of water decreases with a decrease in the ambient pressure, such as a boiling point of 100°C under atmospheric pressure (100,000 Pa) and 0°C under 611 Pa (vacuum). In other words, if the pressure in the drying space S is reduced more than necessary, the moisture contained in the object S may boil and then immediately freeze. This may result in a decrease in the drying speed of the object S. Therefore, in this embodiment, the vacuum pump 30 stops depressurizing the drying space S when the pressure therein drops to a predetermined pressure value (a lower limit value, e.g., 10,000 Pa). The lower limit value can be set to any desired value.

[0046] Since a decrease in the pressure in the drying space S inevitably results in a decrease in its temperature, it is possible to determine whether the above-mentioned lower limit value has been reached by measuring the temperature in the drying space S with the temperature sensor 15B, rather than measuring the pressure with the pressure sensor 15A. Furthermore, when a temperature sensor is used, it is not limited to measuring the temperature of the drying space S, but it is also possible to measure the temperature of the material to be dried MO. In this case, for example, a known infrared temperature sensor may be used as the temperature sensor.

[0047] Furthermore, the determination of whether the above-mentioned lower limit value has been reached is not limited to the use of the pressure sensor 15A or the temperature sensor 15B, but can also be made using a known humidity sensor (not shown). That is, the air containing water vapor generated by drying the material to be dried MO has a tendency to increase in relative humidity (RH) as it cools, so measuring this also makes it possible to sufficiently determine whether the above-mentioned lower limit value has been reached. Note that such a configuration can be realized by providing the humidity sensor in the drying space S, for example, in the same way as the pressure sensor 15A and the temperature sensor 15B.

[0048] In addition, in this embodiment, the vacuum pump 30 is stopped when the pressure in the drying space S reaches a lower limit specified value, but the vacuum pump 30 may be configured to be stopped when the pressure, steam temperature, and humidity suddenly drop.

[0049] Thereafter, if the central processing unit 61 determines that the specified drying time (e.g., 30 minutes) has not elapsed (step S108), it performs a process to introduce outside air (step S109). Specifically, the central processing unit 61 executes a process to open the intake control valve 41. This causes outside air to flow into the depressurized drying space S, resulting in an increase in the pressure in the drying space S. The process of step S109 (outside air introduction process) may be performed immediately after the process of step S107 (depressurization stop process), or may be performed after a predetermined time has elapsed (e.g., after 30 seconds to 2 minutes have elapsed).

[0050] Next, when the pressure in the drying space S reaches an upper limit specified value (step S110), the central processing unit 61 closes the intake control valve 41 (step S111). This makes it possible to stop the pressure in the drying space S from increasing. The upper limit specified value can be set to a desired value, for example, atmospheric pressure (100,000 Pa). The upper limit specified value is not limited to pressure, and may be temperature or humidity, similar to the above-mentioned lower limit specified value. Furthermore, the intake control valve 41 does not necessarily have to be closed when the pressure in the drying space S reaches the upper limit specified value. The intake control valve 41 may also be closed when the pressure, steam temperature, or humidity rises sharply.

[0051] Thereafter, if the central processing unit 61 determines that the specified drying time (e.g., 30 minutes) has not elapsed (step S112), it again performs the process of step S105 (decompression start process) described above. This reduces the pressure in the drying space S. Note that the process of step S105 (decompression start process) may be performed immediately after the process of step S111 (outside air introduction stop process) is performed, or may be performed after a predetermined time (e.g., 30 seconds to 2 minutes) has elapsed.

[0052] In this manner, in this embodiment, the pressure and pressure in the drying space S are alternately increased and decreased within a predetermined drying time.

[0053] If the central processing unit 61 determines in the processes of steps S108 and S112 that the specified drying time has elapsed, it stops the operation of the heat pump unit 20, the vacuum pump 30, and the air blower 51, and resets the drying time measurement timer (step S113). In this embodiment, after performing this process, the control process is terminated.

[0054] <Test> The results of tests using the drying device of the present invention will be described below with reference to FIGS.

[0055] Figure 4 is a schematic diagram showing an overview of the drying apparatus used in a test to verify the drying time of the material to be dried, Figure 5 is a table showing the test conditions used in the test to verify the drying time of the material to be dried, Figure 6 is a graph showing the transition of pressure inside the drying chamber when a test was conducted under the test conditions of Figure 5, where (a) is a diagram showing the pressure inside the drying chamber for Example 1 and (b) is a diagram showing the pressure inside the drying chamber for Example 2, and Figure 7 is a graph showing the test results when a test was conducted under the test conditions of Figure 5.

[0056] This test was performed using a drying device 101 shown in Fig. 4. The drying device 101 used in this test does not include a device for introducing heated air into the drying space S (heat pump device 20 and circulating air duct 50) like the drying device 1 shown in Fig. 1, but instead includes an electric heater EG arranged in the drying space S.

[0057] The electric heater EG is a so-called electric hot plate, and is a device that can heat and dry an object to be dried MO placed on the top surface of the device body.

[0058] In this test, the workpiece MO was a commercially available face towel (towel cloth, width: 300 mm, length: 340 mm) soaked in 15 g of water (water absorption capacity), and placed on an electric heater EG heated to 70°C to conduct two types of tests (tests relating to Examples 1 and 2) with different test conditions.

[0059] In the test for Example 1, the same process as that of steps S104 to S112 (see Figure 3) described above was performed, i.e., the drying space S was alternately pressurized and depressurized (see Figure 6(a)). In the test for Example 2, the drying space S was depressurized to a predetermined pressure value ("lower limit specified value: 20,000 Pa") and then maintained at this pressure (see Figure 6(b)).

[0060] In this test, the pressure in the drying space S was reduced by closing the intake pressure reducing valve 41 and opening the exhaust control valve 31 while driving the vacuum pump 30. The pressure in the drying space S was increased by closing the exhaust control valve 31 and opening the intake control valve 41 while driving the vacuum pump 30.

[0061] The test conditions for the tests according to Examples 1 and 2 are as follows (see FIG. 5): (Test conditions for Example 1) Lower limit specified value: 20,000 Pa Upper limit specified value: 100,000 Pa Test time: 21 minutes (Test conditions for Example 2) Lower limit specified value: 10,000 Pa Test time: 21 minutes

[0062] As a result of the tests for Examples 1 and 2, the amount of moisture (residual moisture) contained in the workpiece MO after the test time (21 minutes) had elapsed was as follows (see Figure 7): Test for Example 1: 0 g Test for Example 2: 3.13 g

[0063] In this test, in addition to the tests for Examples 1 and 2, a test for a comparative example was also conducted to verify the drying time when a moistened face towel (workpiece MO) was dried under atmospheric pressure. The test for the comparative example differed from the tests for Examples 1 and 2 only in the position of the test electric heater EG, but the workpiece MO (a face towel moistened with 15 g (water absorption amount)) and the heating temperature (70°C) of the electric heater EG were the same.

[0064] As a result of the test for the comparative example, the time required for the face towel (workpiece MO) to completely dry, i.e., the time required for the residual moisture content to reach "0 g", was "220 minutes".

[0065] As is clear from the above test results, it was confirmed that the drying time can be shortened by reducing the pressure in the drying space S to a predetermined level while heating the workpiece MO (test related to Example 2).

[0066] Furthermore, it was demonstrated that the drying time can be further shortened by alternately pressurizing and depressurizing the drying space S within a predetermined pressure range while heating the workpiece MO (test related to Example 1).

[0067] As described above, the drying apparatus 1 according to this embodiment includes the drying chamber 10 having the drying space S for accommodating the material to be dried (MO), the vacuum pump 30 communicating with the drying space S, the measuring device 15 capable of measuring at least one of the pressure and temperature of the drying space S, and the control device that controls the vacuum pump 30 to reduce the pressure in the drying space S based on the measurement results from the measuring device 15. With this configuration, in this embodiment, by reducing the pressure in the drying space S, it is possible to lower the boiling point of the moisture contained in the material to be dried (MO). As a result, the drying time of the material to be dried (MO) can be shortened.

[0068] The drying apparatus 1 according to this embodiment further includes a pressurizing mechanism 40 that pressurizes the drying space S, and is configured to control the pressurizing mechanism 40 based on the measurement results from the measuring device 15 to pressurize the drying space SO. With this configuration, in this embodiment, by pressurizing the depressurized drying space S, it is possible to raise the boiling point of the moisture contained in the material to be dried MO. As a result, it is possible to prevent unnecessary freezing of the moisture contained in the material to be dried MO, thereby reliably shortening the drying time of the material to be dried MO.

[0069] Furthermore, the drying device 1 according to this embodiment is configured to alternately pressurize and depressurize the drying space S. With this configuration, the present embodiment can efficiently dry the object to be dried MO, thereby more reliably shortening the drying time of the object to be dried MO.

[0070] The drying device 1 according to this embodiment further includes a heat pump device 20 (radiator 22) that heats the drying space S, and is configured to control the heat pump device 20 to heat the drying space S. With this configuration, the drying device 1 according to this embodiment can efficiently dry the material to be dried MO.

[0071] <Modifications> In the present embodiment, the intake control valve 41 is closed to prevent outside air from flowing into the drying space S while the drying space S is being depressurized, but such an inflow can also be permitted. In this case, the opening of the intake control valve 41 can be controlled to control the amount of outside air flowing into the drying space S. In addition, in the present embodiment, the vacuum pump 30 is stopped while the drying space S is being pressurized (while the intake control valve 41 is open), but it may be operated. In this case, it is also possible to control the amount of suction by the vacuum pump 30, as with the intake control valve 41 described above. With this configuration, the pressure in the drying space S can be adjusted accurately, thereby further shortening the drying time of the material MO to be dried.

[0072] In addition, in this embodiment, the air in the drying space S is configured to be circulated (see Figure 1), but it can also be configured not to be circulated, for example, as in the drying device 201 shown in Figure 8.

[0073] Here, a description will be given of such a drying device 201. As shown in Fig. 8, the drying device 201 includes a pressurizing mechanism 240, a heat absorption air passage 252, and a heat absorption control damper 253.

[0074] The pressurizing mechanism 240 includes a heat-dissipation control damper 241, a heat-dissipation air passage 242, and a heat-dissipation air blower 243. The heat-dissipation control damper 241 is provided with a valve body electrically movable between a closed position and an open position, and a known motor damper, for example, may be used. One end of the heat-dissipation air passage 242 is connected to the air outlet 10A of the drying chamber 10, while the other end is open to the outside. The heat-dissipation control damper 241, the heat-dissipation air blower 243, and the radiator 22 of the heat pump unit 10 are installed in this order along the heat-dissipation air passage 242 from the other end to the first end. The heat-dissipation air blower 243 is a blower fan for drawing outside air into the drying space S.

[0075] The heat dissipation damper 241 and the heat dissipation blower 243 are configured to be driven in accordance with a control signal transmitted from the control device 60. The amount of heated air flowing into the drying space S can be appropriately adjusted by controlling the opening degree of the heat dissipation damper 241 and the air volume of the heat dissipation blower 243.

[0076] One end of the heat-absorbing air duct 252 is connected to the first exhaust port 10B of the drying chamber 10, while the other end is open to the outside. The air blower 51, the heat absorber 24, and the heat-absorbing control damper 253 are installed in this order along the heat-absorbing air duct 252. Like the heat-dissipating damper 241, the heat-absorbing damper 253 is a device equipped with a valve body that can be electrically moved between a closed position and an open position. For example, a known motor damper can be used. The heat-absorbing damper 251 is configured to be driven in accordance with a control signal transmitted from the control device 60. The amount of heated air exhausted from the drying space S can be appropriately adjusted by controlling the opening degree of the heat-absorbing damper 251 and the air volume of the air blower 51.

[0077] Even in this configuration, it is possible to increase or decrease the pressure in the drying space S, similarly to the drying device 1 shown in FIG.

[0078] Furthermore, although the heating device 201 shown in FIG. 8 is provided with a heat pump device 20, a known electric heater 320 can be provided instead (see "drying device 301" in FIG. 9). Furthermore, regardless of the heating means such as the heat pump device 20 or the electric heater 320, as described above, it is possible to heat the air introduced into the drying chamber 10 using a heat source such as gas or steam. Furthermore, when a temperature sensor is used, it is not limited to measuring the temperature of the drying space S, but it can also measure the temperature of the material to be dried MO. In this case, for example, a known infrared temperature sensor can be used as the temperature sensor.

[0079] Furthermore, in the drying devices 201, 301 shown in Figures 8 and 9, a vacuum pump 30 and an air blower 51 are provided, but it is also possible to omit the air blower 31, for example, by providing the vacuum pump 30 at the position of the air blower 31 on the paper surface.

[0080] 8 and 9 are provided with a heat source (heat pump unit 20, electric heater 320) for generating heated air, but this may be omitted. This also applies to the drying device 1.

[0081] Furthermore, in the above embodiments, the heat pump unit 20 (radiator 22), the electric heater (electric heater 320), and the gas or steam heating source are exemplified as heating means for heating the air, but the heating of the air by these heating means can also be controlled depending on the state of the object to be dried MO (for example, whether it is frozen or not, and the degree of dryness). With this configuration, the object to be dried MO can be dried more efficiently.

[0082] In each of the above embodiments, one set of the pressurizing mechanism 40, 240 and the vacuum pump 30 is used to pressurize and depressurize one drying space S (drying chamber 10), but it may also be configured to pressurize and depressurize multiple drying spaces S. Such a drying device will be described below with reference to FIG.

[0083] The drying apparatus 401 shown in Fig. 10 has a configuration in which a drying chamber 410, an upstream branch air duct 450A, and a downstream branch air duct 450B are added to the configuration of the drying apparatus 1 shown in Fig. 1. Furthermore, while the vacuum pump 30 is connected to the drying chamber 10 in the example shown in Fig. 1, in this modification, it is connected to the upstream branch air duct 450A. Note that the drying chamber 410 is similar to the drying chamber 10, and therefore a description thereof will be omitted.

[0084] The upstream branch air passage 450A branches off from the upstream side of the circulation air passage 50 and extends, with its tip connected to the first exhaust port 10B of the drying chamber 410. An upstream control valve 452A is attached midway along the upstream branch air passage 450A. Meanwhile, the downstream branch air passage 450B branches off from the downstream side of the circulation air passage 50 and extends, with its tip connected to the air outlet 10A of the drying chamber 410. A downstream control valve 452B is attached midway along the downstream branch air passage 450B.

[0085] In addition, in this modified example, an upstream control valve 451A is installed midway through the circulation air passage 50, upstream of the branch position where the upstream branch air passage 450A branches off, and a downstream control valve 451B is installed downstream of the branch position where the downstream branch air passage 450B branches off.

[0086] The upstream control valves 451A, 452A and the downstream control valves 451B, 452B are devices each provided with a valve element that is electrically movable between a closed position and an open position, and for example, a known solenoid valve, an electric valve, or a motor damper can be used. Furthermore, the upstream control valves 451A, 452A and the downstream control valves 451B, 452B are configured to be driven in accordance with a control signal transmitted from the control device 60.

[0087] In the drying apparatus 401 configured as described above, when the drying space S of the drying chamber 10 is pressurized or depressurized, the upstream control valve 451A and the downstream control valve 451B are opened and the upstream control valve 452A and the downstream control valve 452B are closed. On the other hand, when the drying space S of the drying chamber 410 is pressurized or depressurized, the upstream control valve 451A and the downstream control valve 451B are closed and the upstream control valve 452A and the downstream control valve 452B are opened. Note that when the drying spaces S of the drying chambers 10 and 401 are pressurized or depressurized simultaneously, all of the upstream control valves 451A, 452A and the downstream control valves 451B, 452B may be opened.

[0088] 10 illustrates an example in which two drying chambers 10 and 410 are pressurized and depressurized, but it is also possible to configure the drying apparatus 410 so that three or more drying chambers can be pressurized and depressurized. In addition, in the drying apparatus 410 according to this modification, the vacuum pump 30 is attached to the upstream branch air duct 450A, but it is also possible to attach the vacuum pump 30 to each of the drying chambers 10 and 410, as in the drying apparatus 1 shown in FIG.

[0089] The above-described embodiments do not limit the present invention, and modifications that do not deviate from the spirit of the present invention are included in the scope of the present invention.

[0090] Furthermore, the structure, system, program, and the like of the present invention can be modified in various ways without departing from the spirit of the present invention.

[0091] For example, two or more members can be combined into one, or conversely, one member can be made up of two or more separate members and connected together.

[0092] Furthermore, the above embodiment is merely one of the best modes currently available.

[0093] Furthermore, the control may be performed by a higher-level control section, or by a lower-level control section.

[0094] Furthermore, the order of control can be changed as appropriate as long as it has a predetermined effect.

[0095] The drying apparatus of the present invention can be used to dry all kinds of items to be dried, such as clothes and food.

[0096] DESCRIPTION OF SYMBOLS 1, 101, 201, 301, 401: Drying device 2: Drying device main body 10, 410: Drying chamber 10A: Air outlet 10B: First exhaust port 10C: Second exhaust port 11: Rotating drum 12: Rotating drum motor 15: Measuring device (measuring means) 15A: Pressure sensor 15B: Temperature sensor 16: Drying time measuring timer 20: Heat pump device 21: Compressor 22: Radiator 23: Throttle valve 24: Heat absorber 25: Heat pump pipe 320: Heating device 30: Vacuum pump (pressure reducing means) 31: Exhaust control valve 32: Exhaust pipe 40, 40', 240: Pressurizing mechanism (pressurizing means) 41, 41': Intake control valve 42, 42' : Intake pipe 241 : Heat radiation control damper 242 : Heat radiation air duct 243 : Air blower 50 : Circulation air duct 51 : Air blower 52 : Reserve space 53 : Heat absorption bypass air duct 54 : Heat absorption control valve 55 : Heat absorption air blower 56 : Heat radiation bypass air duct 57 : Heat radiation control valve 58 : Heat radiation air blower 252 : Heat absorption air duct 253 : Heat absorption control damper 450A : Upstream branch air duct 450B : Downstream branch air duct 451A, 452A : Upstream control valve 451B, 452B : Downstream control valve 60 : Control device (control means) 61 : Central processing unit 62 : Storage device 63 : Bus MO : Material to be dried S : Drying space EG : Electric heater

Claims

1. A drying device comprising: a drying chamber having a drying space for accommodating an object to be dried; a pressure reducing means for reducing the pressure in the drying space; a measuring means capable of measuring at least one of the pressure, temperature, humidity, and temperature of the object to be dried in the drying space; and a control means for controlling the pressure reducing means based on the measurement results obtained by the measuring means to reduce the pressure in the drying space.

2. The drying device according to claim 1, further comprising a pressurizing means for pressurizing the drying space, wherein the control means controls the pressurizing means based on the measurement results from the measurement means to pressurize the drying space.

3. The drying device according to claim 2, wherein the control means alternately repeats pressurization and depressurization of the drying space.

4. The drying device according to any one of claims 1 to 3, further comprising a heating means for heating the drying space, wherein the control means controls the heating means to heat the drying space.

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