JP7407756B2 - Vacuum drying equipment - Google Patents

Description

The present invention relates to a vacuum drying device that performs drying by reducing the pressure inside a chamber, and particularly relates to a vacuum drying device that can efficiently recover liquid in air discharged from a chamber.

BACKGROUND ART In flat panel displays such as liquid crystal displays, coating films (film patterns) in various shapes such as line segments and rectangular shapes are formed on circuit substrates such as glass and films. The coating film on the substrate is formed by using a coating device such as an inkjet, and then by drying the coating film by using a reduced pressure drying device.

The reduced pressure drying apparatus dries the coating film on the substrate by reducing the pressure of the substrate accommodating part in a state where the substrate is accommodated in the substrate accommodating part of the chamber part (see Patent Document 1 below). Specifically, as shown in FIG. 6, the reduced pressure drying apparatus 100 includes a chamber section 101 that accommodates the substrate W and forms a reduced pressure environment, and a reduced pressure pump 102 (also referred to as a vacuum pump) that reduces the pressure inside the chamber section 101. , and when the chamber section 101 is evacuated by the vacuum pump 102, the chamber section 101 is formed in a reduced pressure environment. Then, by exposing the substrate W housed in the chamber section 101 to a reduced pressure environment, the solvent component of the coating film formed on the substrate W evaporates, so that the coating film can be dried.

Further, a cold trap 103 is provided between the chamber section 101 and the decompression pump 102, and the air discharged from the chamber section 101 is cooled by the cold trap 103. That is, the air exhausted from the chamber section 101 contains the coating liquid (actually, the solvent of the coating liquid. Hereinafter, simply referred to as the coating liquid), and as this air is cooled, the air contains the coating liquid. The contained coating liquid is condensed and temporarily stored at the bottom of the cold trap 103. When the stored coating liquid reaches a certain amount, it is collected from the cold trap 103 and reused.

JP 2019-158157 Publication

However, in recent years, the cost of coating liquids has increased, and there is a desire to efficiently recover coating liquids contained in air. Since the coating liquid that can be recovered by condensation in the cold trap 103 depends on the suction state of the vacuum pump 102, there is a problem in that it is difficult to improve the recovery rate using the cold trap 103 alone. That is, the air that enters the cold trap 103 due to suction by the decompression pump 102 is sucked and discharged without being retained in the cold trap 103 as the decompression pump 102 continues suctioning. Since the operation of the vacuum pump 102 is determined by the pressure control of the chamber section 101, it is not easy to change the operating state of the vacuum pump 102 in order to collect the coating liquid. Therefore, there has been a problem in that it is very difficult to increase the recovery efficiency of the coating liquid contained in the air.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a reduced pressure drying device that can efficiently recover a coating liquid from air discharged from a chamber section.

In order to solve the above problems, the vacuum drying apparatus of the present invention includes a chamber section that forms a vacuum environment, a vacuum pump that reduces the pressure inside the chamber section, and a vacuum dryer that cools the air discharged from the vacuum pump. a cold trap that exhausts the cooled air through an exhaust flow path while condensing a liquid therein, and an exhaust resistance section that suppresses the flow of the air is provided in the exhaust flow path of the cold trap. The exhaust resistance section is provided in an exhaust pipe provided outside the cold trap main body in which the heat exchanger is housed, in the exhaust flow path . According to the vacuum drying device described above, the chamber section, the vacuum pump, and the cold trap are arranged in this order, and the cold trap cools the air discharged from the vacuum pump, so the pressure in the chamber section is directly controlled from the vacuum pump. be able to. That is, since the influence on the operation of the pressure reducing pump can be minimized, it becomes possible to retain the gas in the cold trap. Thereby, the coating liquid can be efficiently recovered from the air discharged from the chamber section. Since the exhaust resistance section is provided in the exhaust flow path of the cold trap, the flow of air exhausted from the exhaust flow path is obstructed. That is, by allowing the air to stay in the heat exchanger, time can be gained for the air to be cooled and condensed, thereby improving the recovery efficiency of the coating liquid in the cold trap.

In other words, the exhaust resistance section is configured to increase the pressure of the cold trap compared to the case where only the exhaust flow path is used, so that the exhaust resistance section is configured to increase the pressure of the cold trap compared to the case where only the exhaust flow path is used. Since the air can be allowed to stagnate, condensation of the air progresses, and the amount of the coating liquid that can be recovered can be increased.

Furthermore, the exhaust resistance section may be formed to have a smaller cross-sectional area than the exhaust flow path.

According to this configuration, the flow of air through the exhaust flow path is suppressed compared to the case where only the exhaust flow path is used, so that air can be retained in the cold trap.

Further, the exhaust resistance section may be configured to be formed by a valve that adjusts the cross-sectional area of the flow path.

According to this configuration, by adjusting the cross-sectional area of the flow path using the valve so as to be smaller than that of the exhaust flow path, the flow of air can be suppressed and the air can be retained in the cold trap.

Further, the exhaust resistance section may include a barrier section that suppresses the flow of the air, and the barrier section may change the flow direction of the air flowing in the exhaust flow path.

According to this configuration, when the air flowing through the exhaust flow path collides with the barrier portion, the flow direction of the air is changed, and the flow of the air is suppressed. Even with this configuration, air can be retained in the cold trap compared to a case where there is only an exhaust flow path.

Further, the exhaust resistance section has a plurality of the barrier sections, and the barrier section is formed with an insertion hole having a flow passage cross-sectional area smaller than that of the exhaust flow passage. The barrier portion may be provided such that the formed insertion hole is displaced around an axis centered on the arrangement direction of the barrier portion.

According to this configuration, since the insertion holes provided in the barrier portions are provided so as to have a phase difference when viewed in the arrangement direction of the barrier portions, air passing through the insertion holes of one barrier portion The flow direction is changed by colliding with the next barrier part, and the flow passes through the plurality of barrier parts so as to pass through the insertion hole of the next barrier part. Since the flow of air is thereby suppressed, the air can be retained in the cold trap compared to the case where only the exhaust flow path is used.

According to the reduced pressure drying device of the present invention, the coating liquid can be efficiently recovered from the air discharged from the chamber section.

It is a figure showing the state where a chamber lid part and a chamber main part of a reduced pressure drying device in one embodiment of the present invention are closed. It is a figure which shows the state where the chamber lid part and chamber main body of the said reduced pressure drying apparatus were spaced apart. It is a figure showing the cold trap in the above-mentioned embodiment. It is a figure which shows the exhaust resistance part in the said embodiment, (a) is a figure which shows the inside of a case main body part, (b) is a figure which shows a barrier part. FIG. 7 is a diagram showing an exhaust resistance section in another embodiment, (a) is a diagram showing a state in which the insertion hole is formed at an angle, and (b) is a diagram showing a state in which a gap is formed in a part of the barrier part. FIG. FIG. 2 is a diagram showing a conventional vacuum drying device.

Embodiments according to the present invention will be described using the drawings.

1 and 2 are diagrams schematically showing a vacuum drying device according to an embodiment of the present invention, and FIG. 1 is a diagram showing a state in which the chamber lid 10 and chamber main body 20 of the vacuum drying device are closed. 2 is a diagram showing a state in which the chamber lid portion 10 and the chamber body 20 are separated.

As shown in FIGS. 1 and 2, the vacuum drying device dries a coating film formed on a substrate W, and includes a chamber section 2 that accommodates the substrate W, and a vacuum drying device that evacuates this chamber section 2. It is equipped with a suction decompression section 3 that The coating film formed on the substrate W can be dried by maintaining the inside of the chamber section 2 in a reduced pressure environment while the substrate W is accommodated in the chamber section 2.

In the following description, the upper side of the paper in FIGS. 1 and 2 is assumed to be above the vacuum drying device, and the bottom side of the paper in FIGS. 1 and 2 is assumed to be below the vacuum drying device.

The chamber section 2 includes a chamber main body 20 and a chamber lid section 10. The chamber lid 10 is formed so that it can be opened and closed with respect to the chamber body 20, and when the chamber lid 10 is in the closed state, the chamber lid 10 and the chamber body 20 hold the substrate W, as shown in FIG. A substrate accommodating portion 30 for accommodating the substrate is formed.

The chamber body 20 holds a substrate W on which a coating film is formed. The chamber body 20 is a box-shaped member with an open top surface, and can hold the substrate W within the chamber body 20. Specifically, the chamber body 20 has a flat plate portion 22, on which the substrate W can be placed. That is, a plurality of pin holes are formed in the plate portion 22, and the lift pins 23 protrude from the pin holes. The substrate W is held by being placed on the tips of the plurality of protruding lift pins 23.

Specifically, a pin accommodating hole is formed in the plate portion 22 at a position corresponding to the pin hole, and the lift pin 23 is embedded in this pin accommodating hole. This lift pin 23 is connected to a drive device (not shown) provided on the lower side of the plate portion 22, and by driving this drive device, the lift pin 23 moves up and down and can be stopped at any position. It looks like this. In this embodiment, the lift pins 23 are housed in the base 21 at an accommodation position, protrude from the plate part 22 and transfer the substrate W (see FIG. 2), and drying process is performed at a drying position (see FIG. 1). ) and can be stopped. When the substrate W is placed on the tip of the lift pin 23 with the lift pin 23 located at the substrate transfer position, the lift pin 23 is lowered by a predetermined amount and the substrate W is held at the drying position. . Note that this pin receiving hole is provided with a seal, so that even when the lift pin 23 is in a protruding state, leakage of the atmosphere in the substrate receiving portion 30 from the pin receiving hole can be prevented.

Further, the chamber lid section 10 forms a substrate accommodating section 30 within the chamber section 2 together with the chamber main body 20. The chamber lid part 10 can be opened and closed with respect to the chamber body 20, and the chamber lid part 10 is formed to be movable up and down with respect to the chamber body 20. That is, an open state is formed when the chamber lid 10 rises relative to the chamber body 20, and a closed state is formed when the chamber lid 10 descends and abuts against the chamber body 20. The chamber lid part 10 has a shape that covers the substrate W held by the chamber body 20, and includes a flat plate part 11 facing the chamber body 20, and a flat plate part 11 facing the chamber body 20. The side wall portion 12 has a shape that protrudes to the side and surrounds the held substrate W. That is, when the chamber lid 10 is in contact with the chamber body 20, the side wall 12 of the chamber lid 10 is in contact with the chamber body 20, so that the substrate accommodating portion 30 that can accommodate the substrate W is formed. It has become.

The substrate accommodating section 30 side of the flat plate section 11 of the chamber lid section 10 is formed into a smooth flat shape. That is, it is formed so that the airflow (flow of air) generated when the substrate accommodating part 30 is sucked is not obstructed. Furthermore, a rib (not shown) is attached to the back side of the substrate accommodating part 30 to prevent the flat plate part 11 from being deformed when the substrate accommodating part 30 is depressurized. As a result, even if the atmosphere inside the substrate accommodating part 30 is sucked and the pressure inside the substrate accommodating part 30 is reduced, the flatness of the flat plate part 11 on the substrate accommodating part 30 side can be maintained, and the substrate accommodating part 30 can maintain its flatness. This makes it possible to suppress the occurrence of uneven drying caused by turbulence in the airflow.

Further, the side wall portion 12 on the substrate accommodating portion 30 side is formed in a smooth flat shape similarly to the flat plate portion 11, and is formed so that the flow of the atmosphere in the substrate accommodating portion 30 is not obstructed. Furthermore, a sealing member 13 is provided on the side wall portion 12 on a surface that comes into contact with the base portion 21 of the chamber body 20 . This seal member 13 is formed in an annular shape so as to surround the held substrate W. Therefore, when the chamber lid part 10 is lowered and brought into contact with the chamber body 20, the seal member 13 comes into contact with the chamber body 20 and is pressed, so that the substrate accommodating part 30 can be brought into a sealed state. .

Further, the chamber section 2 is provided with a suction decompression section 3, and the suction depressurization section 3 can reduce the pressure in the substrate accommodating section 30. The suction decompression section 3 includes a decompression pump 31 (also referred to as vacuum pump 31) that generates suction force, and a suction pipe 32 that connects the decompression pump 31 and the substrate storage section 30. That is, the suction piping 32 is connected to the substrate accommodating part 30, and when the decompression pump 31 is operated, the substrate accommodating part 30 is suctioned through the suction piping 32. As a result, the substrate accommodating section 30 is reduced in pressure to a predetermined pressure lower than atmospheric pressure.

Further, the suction pipe 32 is provided with a cold trap 4. In the example of FIG. 1, it is provided on the downstream side of the decompression pump 31, and the chamber section 2, the decompression pump 31, and the cold trap 4 are arranged in this order. This cold trap 4 cools the air discharged from the chamber part 2 by the decompression pump 31, condenses the liquid in the air (solvent of the coating liquid; hereinafter also simply referred to as coating liquid), and It is for collecting liquid.

As shown in FIG. 3, the cold trap 4 has a cold trap main body 41 with a sealed structure, an intake port 42 that takes in gas to be subjected to heat exchange, and an exhaust port 43 that exhausts the gas after heat exchange. After the target gas is taken in and cooled (heat exchanged) in the cold trap main body 41, the cooled gas can be exhausted from the exhaust port 43. In this embodiment, the cooling pipe 62 is connected to the intake port 42, and the exhaust pipe 33 is connected to the exhaust port 43. Therefore, the air discharged from the decompression pump 31 is taken in from the intake port 42 and cooled (heat exchanged) in the cold trap body 41. Then, by further taking in air from the intake port 42, the cooled air is exhausted from the exhaust port 43 through the exhaust pipe 33. Note that the exhaust port 43 and the exhaust pipe 33 are the exhaust flow path 5, and are versatile in that they have approximately the same opening dimensions (flow path cross-sectional area) as the exhaust port 43 provided in the cold trap body 41. The piping (exhaust piping 33) with a mark is the exhaust flow path 5 of the present invention.

The cold trap main body 41 is a casing portion that can temporarily store gas. In the example of FIG. 3, it is formed of an upper part 41a having a small volume and a lower part 41b having a larger volume than the upper part 41a, and the upper part 41a and the lower part 41b are integrally formed in communication with each other. ing. That is, the lower part 41b is provided with an intake port 42, and the air that flows in through the intake port 42 is accommodated in the lower part 41b and the upper part 41a. In other words, the air taken in is spread over the entire cold trap body 41 and accommodated therein.

Furthermore, a heat exchanger 6 is housed within the cold trap body 41. In this embodiment, the heat exchanger 6 has a plurality of cooling pipes 62, and the gas inside the cold trap main body 41 can be cooled by the refrigerant flowing through these cooling pipes 62. There is. Specifically, the upper portion 41a of the cold trap main body 41 is provided with an inlet 44 and an outlet 45 connected to the chiller 61, and these are connected to a plurality of cooling pipes 62. That is, when the refrigerant cooled by the chiller 61 flows in from the inlet 44, the refrigerant flows in one direction through the plurality of cooling pipes 62, absorbing the heat of the air in the cold trap body 41, and absorbing all the heat. After flowing through the cooling pipe 62, it is discharged from the outlet 45. Then, the discharged refrigerant is cooled again by the chiller 61. Therefore, the air that has flowed in through the intake port 42 comes into contact with the cooling pipe 62 and heat exchange is performed through the refrigerant cooled by the chiller 61.

Further, the cold trap main body 41 is provided with a tray 7 for collecting liquid contained in the air (coating liquid evaporated from the coating film). In the example of FIG. 3, the cold trap body 41 is disposed on the bottom surface. This makes it possible to recover the coating liquid contained in the air. That is, the air that comes into contact with the cooling pipe 62 is cooled and the coating liquid contained in the air is condensed, so that droplet-shaped coating liquid is deposited on the cooling pipe 62. Then, as time passes, the droplet-shaped coating liquid coalesces and fall, and is collected in the tray 7 as a coating liquid. The tray 7 is provided with a discharge port 71, and the coating liquid stored in the tray 7 is collected from the discharge port 71 after a predetermined period of time has elapsed.

Further, an exhaust port 43 for exhausting air within the cold trap body 41 is provided in the upper portion 41 a of the cold trap body 41 and is connected to the exhaust pipe 33 . That is, the air stagnant within the cold trap body 41 is continuously supplied to the cold trap body 41 through the intake port 42 as the air is discharged from the decompression pump 31. The accumulated air is pushed out and exhausted through the exhaust port 43. In the present embodiment, the exhaust port 43 and the exhaust piping 33 are formed to have approximately the same flow path cross-sectional area, so the air discharged from the cold trap body 41 is transferred to the exhaust port 43 and the exhaust piping. 33 to ensure smooth exhaust air.

Further, an exhaust resistance section 8 is provided in the exhaust pipe 33 (exhaust flow path 5). The exhaust resistance section 8 is for suppressing the flow of air in the exhaust flow path 5. That is, compared to the case where there is only the exhaust flow path 5 (for example, only the exhaust port 43 or only the exhaust port 43 and the exhaust pipe 33), it is made difficult for air to flow, and as a result, the pressure in the cold trap body 41 is reduced. is increased, and air can stay in the cold trap body 41 for a longer time than in the case of only the exhaust flow path 5.

In this embodiment, as shown in FIG. 4(a), the exhaust resistance section 8 is formed by a case main body section 81 and a barrier section 82 disposed within the case main body section 81. Specifically, the case main body part 81 is formed in a cylindrical shape, and has an import part 83 connected to the exhaust pipe 33 at both ends in the axial direction (longitudinal direction), and an out part on the opposite side of the import part 83. It has a port section 84. That is, air taken in from the import section 83 is discharged from the out port section 84. Note that the import portion 83 and the out port portion 84 are formed to have a flow passage cross-sectional area approximately the same size as the exhaust pipe 33, and the air flowing through the exhaust pipe 33 is substantially resisted at the import portion 83. It is taken into the case main body part 81 without any resistance, and is ejected from the out port part 84 without receiving substantial resistance.

This case main body part 81 is for suppressing the flow of air supplied from the import part 83. That is, the case main body part 81 is provided with a plurality of barrier parts 82, and the barrier parts 82 prevent the flow of air. As shown in FIGS. 4(a) and 4(b), the barrier portion 82 is a disk-shaped plate member, and is inserted into the case body portion 81 so that its thickness direction coincides with the axial direction (longitudinal direction). It is located. In the example shown in FIG. 4A, three barrier portions 82 are arranged within the case body portion 81 at approximately equal intervals. That is, the barrier portion 82 is provided within the case body portion 81 so as to block the flow of air with almost no gap formed between the inner wall of the case body portion 81 and the outer diameter portion of the barrier portion 82. .

Further, the barrier portion 82 is formed with two insertion holes 82a that penetrate in the thickness direction, and are formed so that air can pass through the insertion holes 82a. In this embodiment, the insertion holes 82a are arranged at positions facing each other in the 180 degree direction (the insertion holes 82a are indicated by solid lines in FIG. 4(b)). The insertion hole 82a is formed so that its cross-sectional area is smaller than the flow-path cross-sectional area of the exhaust flow path 5 (exhaust port 43 and exhaust pipe 33). That is, the insertion hole 82a is formed so that air flows through it more easily than in the exhaust flow path 5.

Moreover, the three barrier parts 82 are arranged so that the insertion holes 82a of the adjacent barrier parts 82 are not aligned in one direction (the direction in which the barrier parts 82 are arranged). In this embodiment, as shown in FIG. 4(b), the three barrier parts 82 are arranged so that their insertion holes 82a are shifted by 60 degrees. That is, as shown in FIG. 4(a), the barrier portion 82 closest to the import portion 83 is located at a position where the insertion hole 82a is inclined 60 degrees clockwise with respect to the vertical direction (indicated by the broken line in FIG. 4(b)). It is arranged so that it becomes the insertion hole 82a). The next barrier part 82 is arranged so that the insertion holes 82a are aligned in the vertical direction (the insertion holes 82a shown by solid lines in FIG. 4(b)). The next barrier part 82 is arranged so that the insertion hole 82a is inclined 60 degrees counterclockwise with respect to the vertical direction (the insertion hole 82a indicated by the two-dot chain line in FIG. 4(b)). . As a result, the air supplied from the import portion 83 cannot flow in a straight line along the axial direction because it passes through each of the through holes 82a, but instead flows through each of the through holes 82a. Thereby, the flow of air can be suppressed compared to the case where only the exhaust flow path 5 is used, and the air can be retained in the cold trap 4 for a longer period of time than when only the exhaust flow path 5 is used. Therefore, by providing the exhaust resistance section 8 in the exhaust flow path 5 of the cold trap 4, air is retained in the cold trap 4, thereby making it possible to recover more coating liquid.

As described above, according to the vacuum drying apparatus in the above embodiment, the chamber section 2, the vacuum pump 31, and the cold trap 4 are arranged in this order, and the cold trap 4 is configured to cool the air discharged from the vacuum pump 31. , the pressure of the chamber section 2 can be directly controlled from the decompression pump 31. Since the exhaust resistance section 8 is provided in the exhaust flow path 5 of the cold trap 4, the flow of air exhausted from the exhaust flow path 5 is obstructed. That is, by retaining the air within the heat exchanger, time for the air to be cooled and condensed can be gained, so that the recovery efficiency of the coating liquid in the cold trap 4 can be improved.

Further, in the above embodiment, an example has been described in which the insertion hole 82a penetrates through the barrier portion 82 in the thickness direction, but it may penetrate in a direction oblique to the thickness direction. Specifically, as shown in FIG. 5(a), by penetrating the barrier portion 82 in a direction having a predetermined angle with the thickness direction, the air flow is changed by the insertion hole 82a. can be hindered. In this case, even if the openings of the insertion holes 82a are aligned in one direction and the adjacent barrier portions 82 are placed in opposing positions, the slanted insertion holes 82a prevent the air flow. can be suppressed.

Further, in the above embodiment, an example in which the insertion holes 82a are provided in two places in the barrier portion 82 has been described, but a large number of insertion holes 82a may be provided, or only one insertion hole 82a may be provided. It is effective to avoid arranging the insertion holes 82a in the direction in which the barrier portions 82 are arranged in order to suppress the flow of air.

Further, in the above embodiment, an example in which three barrier parts 82 of the exhaust resistance part 8 are provided has been described, but four or more barrier parts 82 may be provided, and one or two barrier parts 82 may be provided. By avoiding the insertion holes 82a from being lined up in the arrangement direction of the barrier portions 82, air flow can be more effectively suppressed by providing a plurality of through holes 82a.

Further, in the above embodiment, an example in which the insertion hole 82a is provided in the barrier part 82 of the exhaust resistance part 8 has been described, but as shown in FIG. 5(b), a gap 82b is formed in a part of the barrier part 82. It may be. That is, by forming the gap 82b so that its cross-sectional area is smaller than that of the exhaust flow path 5, it can perform the same function as the insertion hole 82a. Furthermore, when a plurality of barrier parts 82 are provided, the gaps 82b are formed to avoid lining up in the arrangement direction of the barrier parts 82, thereby changing the air flow direction and effectively controlling the air flow. This is preferable in that it can be suppressed to

Further, in the above embodiment, an example in which the barrier portion 82 is provided in the exhaust resistance portion 8 has been described, but the exhaust resistance portion 8 may be a valve. That is, a valve may be attached to the exhaust pipe 33 and the opening state of this valve may be adjusted to be smaller than the cross-sectional area of the exhaust flow path 5. Even with this configuration, the flow of air can be suppressed compared to the case where only the exhaust flow path 5 is provided.

Furthermore, in the above embodiment, an example was described in which a passage cross-sectional area smaller than that of the exhaust flow path 5 is formed in the exhaust resistance section 8; The exhaust resistance section 8 may be formed to be smaller in size than the exhaust resistance section 8, or may be formed so that the entire flow path of the exhaust resistance section 8 acts as a resistance to the flow of air. For example, if the exhaust resistance part 8 is a pipe with a smaller cross-sectional area than the exhaust flow path 5, or if the exhaust resistance part 8 is a pipe with a bent part, the bent part is used to air the air. It may be something that acts as a resistance to the flow of air and suppresses the flow of air.

2 Chamber part 4 Cold trap 5 Exhaust flow path 8 Exhaust resistance part 31 Decompression pump 82 Barrier part 82a Insertion hole

Claims (6)

a chamber part that forms a reduced pressure environment;
a decompression pump that depressurizes the inside of the chamber;
a cold trap that cools the air discharged from the decompression pump to condense liquid in the air and exhaust the cooled air through an exhaust flow path;
Equipped with
The exhaust flow path of the cold trap is provided with an exhaust resistance section that suppresses the flow of the air, and the exhaust resistance section is located in the cold trap main body in which the heat exchanger is housed in the exhaust flow path. A reduced pressure drying device characterized in that it is installed in an exhaust pipe provided on the outside of the . The reduced pressure drying apparatus according to claim 1 , wherein the exhaust resistance section is formed to increase the pressure of the cold trap compared to a case where only the exhaust flow path is provided. The reduced pressure drying apparatus according to claim 1 or 2 , wherein the exhaust resistance section is formed so that a cross-sectional area of the exhaust flow path is smaller than that of the exhaust flow path. The reduced pressure drying apparatus according to any one of claims 1 to 3 , wherein the exhaust resistance section is formed by a valve that adjusts a cross-sectional area of the flow path. The exhaust resistance section has a barrier section that suppresses the flow of the air, and the flow direction of the air flowing in the exhaust flow path is changed by the barrier section . 3. The vacuum drying device according to any one of 3 . The exhaust resistance section has a plurality of barrier sections, each of which is formed with an insertion hole having a flow passage cross-sectional area smaller than that of the exhaust flow path. 6. The reduced pressure drying apparatus according to claim 5 , wherein the barrier portion is provided such that the through hole is displaced around an axis centered on the arrangement direction of the barrier portion.

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