Gas shielding device and gas shielding method

Abstract

To provide a gas shield device and a gas shield method capable of efficiently maintaining pressure in an object space.SOLUTION: A gas shield device for gas-shielding an opening of a structure including a first section having the opening and a second section connected to the first section at the opening and having a pressure higher than that of the first section includes a nozzle arranged in an entire area of one side of the opening and forming a plate-like jet flow covering an entire surface of the opening from the one side of the opening toward the corresponding side of the opening, and a gas supply part for supplying fluid to be injected to the nozzle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a gas shielding device and a gas shielding method. [Background technology]

[0002] For example, in a factory, atmospheric conditions vary for each process. For example, positive pressure control is known, in which a fluid is supplied to a target space to increase the internal pressure of the target space relative to other spaces, in order to prevent the intrusion of a fluid from another space into the target space. For example, Patent Document 1 describes a beverage filling device in which a heated gas is supplied to the space to create a positive pressure in the space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5725097 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to maintain a positive pressure in the target space, it is necessary to continuously supply a fluid to the target space to maintain a pressure difference. Patent Document 1 describes forming an air curtain in a portion of the space, but this leaves other spaces connected.

[0005] The present disclosure has been made in view of the above, and aims to provide a gas shielding device and a gas shielding method that can efficiently maintain the pressure in a target space. [Means for solving the problem]

[0006] The gas shielding device according to the present disclosure is a gas shielding device that gas-shields an opening of a structure having a first compartment having an opening, and a second compartment connected to the first compartment by the opening and having a higher pressure than the first compartment, and includes: a nozzle that is arranged over the entire area of ​​one side of the opening and forms a plate-shaped jet that covers the entire surface of the opening from one side of the opening toward the corresponding side of the opening; and a gas supply unit that supplies a fluid to be sprayed to the nozzle.

[0007] The gas shielding method according to the present disclosure is a gas shielding method for gas-shielding an opening in a structure having a first compartment having an opening and a second compartment connected to the first compartment by the opening and having a higher pressure than the first compartment, the method comprising: supplying a fluid to be sprayed to a nozzle arranged over the entire area of ​​one side of the opening; spraying the fluid from the nozzle; and forming a plate-shaped jet that covers the entire surface of the opening from one side of the opening toward the corresponding side of the opening. [Effects of the Invention]

[0008] According to the present disclosure, pressure in a target space can be efficiently maintained. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the general configuration of a compartment unit equipped with a gas shielding device according to this embodiment. [Figure 2] FIG. 2 is a perspective view showing the relationship between the gas shielding device and the opening. [Figure 3] FIG. 3 is a cross-sectional view showing a schematic configuration of the nozzle. [Figure 4] FIG. 4 is an explanatory diagram for explaining the gas shield formed by the gas shield device. [Figure 5] FIG. 5 is a schematic diagram showing the general configuration of a gas shielding device according to another embodiment. [Figure 6] FIG. 6 is a schematic diagram showing the general configuration of a gas shielding device according to another embodiment. [Figure 7] FIG. 7 is a perspective view showing the relationship between the gas shielding device shown in FIG. 6 and the opening. [Figure 8] FIG. 8 is a cross-sectional perspective view of the gas shielding device. [Figure 9] FIG. 9 is a schematic diagram showing the general configuration of a gas shielding device according to another embodiment. [Figure 10] FIG. 10 is a schematic diagram showing the general configuration of a gas shielding device according to another embodiment. [Figure 11] FIG. 11 is a schematic diagram showing the general configuration of a gas shielding device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0011] FIG. 1 is a schematic diagram showing the overall configuration of a compartment unit including a gas shielding device according to this embodiment. The compartment unit 10 shown in FIG. 1 has a first compartment 12 and a second compartment 14. The first compartment 12 and the second compartment 14 are connected by an opening 16. In the compartment unit 10, the first compartment 12 and the second compartment 14 are connected by the opening 16, and the first compartment 12 and the second compartment 14 are controlled at different pressures. The compartment unit 10 of this embodiment may be, for example, a compartment in a manufacturing factory, and articles to be manufactured move between the first compartment 12 and the second compartment 14 via the opening 16. Note that in the compartment unit 10, the first compartment 12 and the second compartment 14 are connected by the opening 16, and it is sufficient that the controlled pressure values ​​of the respective compartments are different.

[0012] The first compartment 12 is a compartment managed by negative pressure. In the first compartment 12, openings 16 and 30 are formed as portions through which a fluid can flow, and a suction pipe 32 is connected. The first compartment 12 has a wall surface other than the portion through which the fluid can flow. Opening 16 will be described later. Opening 30 is formed on a wall surface separate from opening 16. Opening 30 is connected to another space at a higher pressure than the first compartment 12, for example, atmospheric pressure. Opening 30 forms a gas flow 60 through which air from the outside flows into the first compartment 12.

[0013] The suction pipe 32 is connected to the first compartment 12. A suction mechanism 34 is disposed in the suction pipe 32. The suction mechanism 34 is a blower or the like, and forms a gas flow 64 that sucks air from the first compartment 12 through the suction pipe 32. When the air inside the first compartment 12 is sucked in by the suction mechanism 34, the pressure inside the first compartment 12 becomes negative.

[0014] The second compartment 14 is a compartment that is managed under positive pressure. An opening 16 is formed in the second compartment 14 as a portion through which a fluid can flow, and an air supply pipe 40 is connected to the opening 16. The second compartment 14 has walls other than the portion through which the fluid can flow. The opening 16 will be described later.

[0015] The air supply pipe 40 is connected to the second section 14. An air supply mechanism 42 is disposed in the air supply pipe 40. The air supply mechanism 42 is a blower or the like, and forms a gas flow 62 that supplies air to the second section 14 via the air supply pipe 40. When air is supplied to the interior of the second section 14 by the air supply mechanism 42, the pressure inside becomes positive.

[0016] The opening 16 connects the first compartment 12 and the second compartment 14. The opening 16 in this embodiment is a pipe line having a predetermined length in a direction perpendicular to the opening surface. The compartment unit 10 may have a structure in which the first compartment 12 and the second compartment 14 are separated by a wall, and the opening 16 may be a hole formed in the wall. The opening surface of the opening 16 in this embodiment is rectangular. However, the shape of the opening 16 is not limited to this.

[0017] The gas shielding device will be described using Fig. 2 to Fig. 4 in addition to Fig. 1. Fig. 2 is a perspective view showing the relationship between the gas shielding device and an opening. Fig. 3 is a cross-sectional view showing a schematic configuration of a nozzle. Fig. 4 is an explanatory diagram for explaining the gas shield formed by the gas shielding device.

[0018] The gas shielding device 20 is disposed in the opening 16. The gas shielding device 20 forms a gas shield in the opening 16 that suppresses the inflow of gas from the second compartment 14 to the first compartment 12. The gas shielding device 20 includes a nozzle 50 and a gas supply unit 51. The nozzle 50 is disposed on the wall surface of the first compartment 12 on which the opening 16 is formed. The nozzle 50 is configured to blow air from its tip to form a gas shield jet 66, and is disposed over the entire area of ​​one side 16a of the opening 16. The nozzle 50 is disposed in a direction that sprays air from the side 16a on which the opening 16 is disposed toward the opposing side 16b of the opening 16, i.e., in a direction that sprays the gas shield jet 66.

[0019] As shown in Fig. 3, the nozzle 50 has an integral structure in which a nozzle base 70 and a nozzle tip 72 are integrated. Flow straightening mechanisms 76, 78, and 80 are disposed inside the nozzle 50. The nozzle base 70 is box-shaped along one side 16a of the opening 16, and is connected to the gas supply pipe 62 of the gas supply unit 51. The nozzle base 70 has a constant thickness in the direction of the gas shield jet 66, and the flow straightening mechanisms 76 and 78 are disposed inside. The nozzle base 70 serves as a header that equalizes the injected gas in the direction along the one side 16a.

[0020] The nozzle tip 72 is connected to the nozzle base 70. The nozzle tip 72 has a constricted shape, with the cross-sectional area of ​​the plane perpendicular to the gas shield jet 66 decreasing with increasing distance from the nozzle base 70. The cross-sectional area of ​​the nozzle tip 72 decreases so that the surface opposite the wall surface on which the opening 16 is formed gradually approaches the wall surface on which the opening 16 is formed. The end of the nozzle tip 72 opposite the connection with the nozzle base 70 is the outlet 74. The outlet 74 is a long, narrow opening extending along one side 16a. A flow straightening mechanism 80 is disposed in the outlet 74. The gas passing through the nozzle tip 72 is constricted by the constricted shape, and an elongated airflow is ejected along the outlet 74, which is long in the direction along the side 16a and short in the direction perpendicular to the side 16a. Note that the nozzle 50 is not limited to the constricted shape of this embodiment. The nozzle 50 need not have a constricted portion as long as it can form the gas shield jet 66. The nozzle 50 may also be configured such that a plurality of nozzles are arranged side by side on one side 16a, and the gas shield jet 66 is sprayed from the entire area of ​​the one side 16a.

[0021] The flow straightening mechanisms 76, 78, 80 are mechanisms that average the flow in the direction along the side 16a and straighten the flow direction of the fluid in the direction along the gas shield jet 66. The flow straightening mechanism 76 is disposed in the nozzle base 70.

[0022] The flow straightening mechanism 76 has a structure in which multiple plates extending in a direction along the gas shield jet 66 and in a direction along one side 16a are arranged at predetermined intervals in a direction perpendicular to the surfaces of the plates. The gas that flows into the nozzle base 70 passes through the gaps between the plates and moves toward the nozzle tip 72. By passing through the flow straightening mechanism 76, the gas is averaged in the direction along the one side 16a, and the flow direction of the fluid is straightened to the direction along the gas shield jet 66.

[0023] The flow straightening mechanism 78 is a mesh-like structure that is arranged downstream (toward the nozzle tip 72) of the nozzle base 70 relative to the flow straightening mechanism 76. The gas that flows into the nozzle base 70 and passes through the flow straightening mechanism 76 passes through the mesh holes of the flow straightening mechanism 78 and moves toward the nozzle tip 72. By passing through the flow straightening mechanism 78, the gas is averaged in the direction along the one side 16a, and the flow direction of the fluid is straightened to the direction along the gas shield jet 66.

[0024] The flow straightening mechanism 80 is a mesh-like structure disposed at the outlet 74. The gas that flows into the nozzle base 70 and passes through the flow straightening mechanisms 76 and 78 is contracted at the nozzle tip 72 and then sprayed after passing through the mesh holes of the flow straightening mechanism 80. As the gas passes through the flow straightening mechanism 80, the gas is averaged in the direction along the one side 16a, and the flow direction of the fluid is straightened to the direction along the gas shield jet 66.

[0025] Gas supply unit 51 supplies gas to be sprayed to nozzle 50. Gas supply unit 51 has an air supply pipe 52 and a blower mechanism 54. One end of air supply pipe 52 is connected to nozzle base 70 of nozzle 50, and the other end is open to the outside of first section 12. Blower mechanism 54 is disposed in air supply pipe 52 and forms a gas flow in air supply pipe 52 that supplies air to nozzle 50.

[0026] The gas shielding device 20 forms a gas shielding jet 66 by ejecting gas supplied by the blower mechanism 54 of the gas supply unit 51 from the outlet 74 of the nozzle 50. As shown in FIG. 4, the gas shielding jet 66 becomes a plate-shaped jet by being ejected in the same direction from the outlet 74 of the nozzle 50. As described above, the gas shielding jet 66 is ejected from one side 16a of the opening 16 where the nozzle 50 is disposed toward the opposing side 16b. As a result, the gas shielding jet 66 becomes a jet that overlaps the entire surface of the opening 16, as shown in FIG. 2.

[0027] As a result, the gas shield jet 66 takes a shape that blocks the entire surface of the opening 16, and the gas flow 68 that flows from the second compartment 14 into the first compartment 12 through the opening 16 can be reduced.

[0028] The compartment unit 10 is provided with a gas shield device 20, which forms a gas shield jet 66 at the opening 16 and reduces the gas flow 68 leaking from the second compartment 14, thereby reducing the gas flow 62 supplied from the air supply pipe 40. This allows for more efficient positive pressure management of the second compartment 14.

[0029] By shaping the nozzle tip 72 so that the cross-sectional area decreases on the side opposite the wall surface on which the opening 16 is formed, the nozzle tip 72 can be made to approach the wall surface on which the opening 16 is formed, and the outlet 74 can be made to approach the opening 16, and the gas shield jet 66 ejected from the outlet 74 can be made to be a jet that follows the opening 16.

[0030] By arranging the flow straightening mechanisms 76, 78, and 80 in the nozzle 50, the gas shield jet 66 can be made into a more plate-like jet, and the flow of gas at the opening 16 can be reduced.

[0031] The second section 14 of this embodiment may further include openings. The second section 14 can be made to have the same state as the openings 16 by disposing a gas shielding device 20 in each of the openings.

[0032] Fig. 5 is a schematic diagram showing the general configuration of a gas shielding device according to another embodiment. Of the compartment unit 10a shown in Fig. 5, components having the same functions as those of the compartment unit 10 in the embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted. The compartment unit 10a is similar to the compartment unit 10 in that a first compartment 12 and a second compartment 14 are connected by an opening 16.

[0033] The gas shielding device 20a disposed in the compartment unit 10a has a nozzle 50a and a gas supply unit 51a. The nozzle 50a has the same configuration as the nozzle 50. The gas supply unit 51a has an air supply pipe 52a and an air blowing mechanism 54a. The air supply pipe 52a and the air blowing mechanism 54a are disposed inside the first compartment 12. One end of the air supply pipe 52a is connected to the nozzle 50, and the other end is disposed inside the first compartment 12. The air blowing mechanism 54a is connected to the air supply pipe 52a.

[0034] The compartment unit 10a uses the gas sucked from the first compartment 12 as the gas to be injected from the nozzle 50 of the gas shielding device 20a, thereby suppressing fluctuations in the amount of gas in the first compartment 12 due to the sucked and injected gas. This allows the compartment unit 10a to reduce the amount of gas exhausted from the first compartment 12 through the suction pipe 32. In other words, the negative pressure in the first compartment 12 can be maintained by exhausting the air flowing in as gas flow 60 and the air flowing in as gas flow 68 as gas flow 64. This reduces the amount of air to be sucked in and purged in each section, allowing pressure management of the compartment unit 10a to be performed with less energy. Furthermore, reducing the amount of gas flowing into the first compartment 12 and the second compartment 14 also reduces the processing load for the inflowing gas.

[0035] Fig. 6 is a schematic diagram showing the schematic configuration of a gas shielding device according to another embodiment. Fig. 7 is a perspective view showing the relationship between the gas shielding device shown in Fig. 6 and an opening. Of the compartment unit 10b shown in Figs. 6 and 7, components having the same functions as those of the compartment unit 10a in the embodiment are given the same reference numerals, and detailed description thereof will be omitted. The compartment unit 10b is similar to the compartment unit 10 in that a first compartment 12 and a second compartment 14 are connected by an opening 16.

[0036] The gas shielding device 20b disposed in the compartment unit 10b has a nozzle 50 and a gas supply unit 101. The gas supply unit 101 includes a collector (recovery mechanism) 102, a circulation path 104, and a blower mechanism .

[0037] The collector 102 is disposed at a position facing the nozzle 50, i.e., on the side of the opening 16 opposite to the side on which the nozzle 50 is disposed. The collector 102 sucks in the surrounding air. The collector 102 has openings for sucking in air arranged over the entire area of ​​the side on which the opening 16 is disposed. The collector 102 of this embodiment is disposed on the wall surface on the first section 12 side of the surface on which the opening 16 is formed.

[0038] The circulation path 104 is a pipe that connects the collector 102 and the nozzle 50. The circulation path 104 is disposed at a position that does not overlap with the opening 16. In this embodiment, the circulation path 104 is fixed to the wall surface on which the opening 16 is formed. The blower mechanism 106 is disposed in the circulation path 104 and forms a gas flow from the collector 102 toward the nozzle 50.

[0039] The gas shield device 20b is provided with a collector 102, which allows the air in the vicinity of the side 16b of the opening 16, including the gas shield jet 66 ejected from the nozzle 50, to be sucked in. This makes it possible to suppress the diffusion of the gas shield jet 66 in the vicinity of the side 16b, thereby increasing the effect of the gas shield and further reducing the gas flow 68 at the opening 16.

[0040] Furthermore, by connecting the nozzle 50 and the collector 102 via the circulation path 104, the gas shield jet 66 ejected from the nozzle 50 and the suction of the collector 102 can be realized by a single blower mechanism 106.

[0041] Fig. 8 is a cross-sectional perspective view of a gas shielding device. The gas shielding device shown in Fig. 8 includes a scoop 110 in addition to the components of the gas shielding device shown in Figs. 6 and 7. The scoop 110 is a plate-shaped member that is placed on the surface of the side of the opening 16 on the side of the second compartment 14 where the collector 102 is disposed. The scoop 110 extends along the side of the opening 16, and a portion of the scoop 110 protrudes into the opening 16. The tip of the scoop 110 that protrudes into the opening 16 can have various shapes, such as an arc shape, an ellipse shape, or a wedge shape.

[0042] 8 is provided with a scoop 110, which makes it possible to guide the gas shield jet 66 toward the collector 102 and prevent the gas shield jet 66 from flowing into the second section 14. This reduces the force of the jet. It is also possible to prevent the gas shield jet 66 at the end on the collector 102 side from diffusing to areas other than the collector 102 side.

[0043] Fig. 9 is a schematic diagram showing the general configuration of a gas shielding device according to another embodiment. Of the compartment unit 10c shown in Fig. 9, components having the same functions as those of the compartment unit 10a in the embodiment are given the same reference numerals, and detailed description thereof will be omitted. The compartment unit 10c is similar to the compartment unit 10 in that a first compartment 12 and a second compartment 14 are connected by an opening 16.

[0044] The gas shielding device 20c disposed in the compartment unit 10c has a nozzle 50 and a gas supply unit 101c. The gas supply unit 101c includes a collector (collection mechanism) 102, a circulation path 104, and a blower mechanism 106. The gas supply unit 101c has the same configuration as the gas supply unit 101 except for the position of the collector 102. In the gas supply unit 101c, the collector 102 is disposed on the wall surface of the second compartment 14. The circulation path 104 connects the collector 102 and the nozzle 50.

[0045] By disposing the collector 102 in the second compartment 14, in addition to the gas shield jet 66 sprayed from the nozzle 50, a film of airflow from the nozzle 50 to the collector 102 can also be formed. This makes it possible to make the film of air blocking the opening 16 thicker, and further reduce the gas flowing in the gas flow 68. Note that in the arrangement shown in FIG. 9, gas from the first compartment 12 may be supplied to the nozzle 50 in addition to the gas sucked by the collector 102. For example, a blower mechanism 106 and piping that sucks air into the first compartment 12 may be provided in the circulation path 104, and the ejector effect of the air sucked from the first compartment 12 may be used to suck gas from the collector 102.

[0046] Fig. 10 is a schematic diagram showing the general configuration of a gas shielding device according to another embodiment. Of the compartment unit 10d shown in Fig. 10, components having the same functions as those of the compartment unit 10a in the embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The compartment unit 10d is similar to the compartment unit 10 in that a first compartment 12 and a second compartment 14 are connected by an opening 16.

[0047] The gas shielding device 20d disposed in the compartment unit 10d has a nozzle 50 and a gas supply unit 101d. The gas supply unit 101d includes a collector (recovery mechanism) 102, a circulation path 104, and a blower mechanism 106. Each component of the gas shielding device 20d is disposed on the wall surface of the opening 16 on the second compartment 14 side.

[0048] Even if the gas shield device 20 arranges the nozzle 50 and the gas supply unit 101d on the wall surface of the second compartment 14, i.e., the compartment on the side with higher pressure, by forming a gas shield jet 66 at the opening 16, it is possible to reduce the amount of gas that passes through the opening 16 and flows into the first compartment 12 as a gas flow 68.

[0049] Fig. 11 is a schematic diagram showing the general configuration of a gas shielding device according to another embodiment. Of the compartment unit 10e shown in Fig. 11, components having the same functions as those of the compartment unit 10 in this embodiment are given the same reference numerals, and detailed description thereof will be omitted. The compartment unit 10e is similar to the compartment unit 10 in that a first compartment 12 and a second compartment 14 are connected by an opening 16.

[0050] The gas shielding device 20e disposed in the compartment unit 10e has a nozzle 50 and a gas supply unit 51. The nozzle 50 of the gas shielding device 20e is inclined at an angle θ in a direction away from the opening 16 from a direction parallel to the opening surface of the opening 16. In other words, the nozzle 50 sprays a gas shielding jet 66 in a direction along the opening 16 and in a direction inclined at an angle θ from the opening 16. Here, the angle θ is preferably 10° or less.

[0051] By tilting the nozzle 50 by the angle θ, the gas shield device 20e can prevent the gas shield jet 66 from flowing into the second compartment 14 through the opening 16. In the present embodiment, the angle θ is greater than 0, but by setting the angle θ to 0 as in the above embodiment, the gas shield jet 66 can be formed along the opening 16, and the shielding performance of the opening 16 can be improved.

[0052] In the gas shielding device 20 of the present disclosure, the direction in which the shielding gas jet 66 is formed is not particularly limited and can be any direction, including vertical, horizontal, and oblique directions. The gas shielding device 20 may further be provided with an openable door at the opening 16. In this case, the gas flow 68 can be reduced by operating the gas shielding device 20 with the door open.

[0053] The technical scope of the present disclosure is not limited to the above-described embodiments, and appropriate modifications can be made within the scope of the present disclosure. [Explanation of symbols]

[0054] 10 compartment units 12 Section 1 14 Section 2 16 Aperture 20 Gas shielding device 30 aperture 32 Suction tube 34 Suction mechanism 40 Air intake pipe 42 Air supply mechanism 50 nozzles 51 Gas supply section 52 Air supply pipe 54 Blower mechanism 60, 62, 64, 68 Gas flow 66 Gas shield jet 70 Nozzle base 72 Nozzle tip 74 Air Outlet 76, 78, 80 rectifier mechanism

Claims

1. A gas shielding device for gas-shielding an opening of a structure having a first compartment having an opening and a second compartment connected to the first compartment at the opening and having a higher pressure than the first compartment, a nozzle disposed over the entire area of ​​one side of the opening, the nozzle forming a plate-shaped jet of air from the one side of the opening toward the opposite side of the opening, the jet of air covering the entire surface of the opening; a gas supply unit that supplies a fluid to be sprayed to the nozzle, the gas supply unit includes a recovery mechanism that is disposed on a side of the opening opposite to the side on which the nozzle is disposed and that sucks in a surrounding fluid, and a circulation path that connects the recovery mechanism to the nozzle and supplies the sucked fluid to the nozzle, The gas shield device includes a scoop that is disposed on a surface of the side of the opening on which the recovery mechanism is disposed, facing the second compartment, and that protrudes beyond the opening.

2. 2. The gas shielding device according to claim 1, wherein the nozzle has a flow straightening mechanism therein, and the flow passage area becomes smaller toward the outlet.

3. The gas shielding device according to claim 1 or 2, wherein the gas supply unit supplies the fluid in the first section to the nozzle.

4. The gas shielding device according to claim 1 , wherein the recovery mechanism is disposed on a surface on the first compartment side.

5. The gas shielding device according to claim 1 , wherein the nozzle is disposed on a surface of a side of the opening on which the recovery mechanism is disposed, the side facing the first compartment.

6. The gas shielding device according to any one of claims 1 to 5, wherein the nozzle injects gas in a direction parallel to a surface of the opening.

7. 6. The gas shielding device according to claim 1, wherein the nozzle injects gas in a direction inclined at a predetermined angle away from the opening with respect to a direction parallel to a surface of the opening.

8. 1. A gas shielding method for gas-shielding an opening in a structure having a first compartment having an opening and a second compartment connected to the first compartment by the opening and having a higher pressure than the first compartment, comprising: supplying a fluid to be sprayed to nozzles arranged over the entire area of ​​one side of the opening; a fluid is ejected from the nozzle from one side of the opening toward a corresponding side of the opening, forming a plate-shaped jet that covers the entire surface of the opening; a gas supply unit that supplies a fluid to be sprayed to the nozzle is disposed on a side of the opening opposite to the side on which the nozzle is disposed, and includes a recovery mechanism that sucks in surrounding fluid, and a circulation path that connects the recovery mechanism to the nozzle and supplies the sucked fluid to the nozzle; The gas shielding method, wherein the recovery mechanism is arranged on a surface of the side of the opening on which the recovery mechanism is arranged, facing the second compartment, and includes a scoop protruding beyond the opening.

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