Opening / closing device

Abstract

A switchgear (100) includes: a sealed container (1) filled with an insulating gas; a fixed electrode (5) installed inside the sealed container (1); a movable electrode (3) movably installed inside the sealed container (1) and including a cylinder (32) having a tubular shape, a piston (33) installed in the cylinder (32), and a movable-side contact (31) having a smaller diameter than the cylinder (32) and fixed to the piston (33), the movable-side contact (31) having a vent hole (312a) formed therein, the vent hole interconnecting a puffer chamber (41) and a space inside the movable-side contact (31), the puffer chamber (41) being a space formed between the cylinder (32) and the movable-side contact (31); and a cross-flow forming portion (42) that allows a gas flow to have a component in a direction orthogonal to a central axis of the movable-side contact (31), the gas flow being sucked into the movable-side contact (31) during an opening operation for shifting from a closed state in which the movable electrode (3) is in contact with the fixed electrode (5) to an open state in which the movable electrode (3) is separated from the fixed electrode (5).

Description

Field

[0001] The present disclosure relates to a switchgear that cuts off a current in a sealed container filled with an insulating gas.Background

[0002] A conventionally known device for cutting off a high voltage current includes a switchgear for cutting off a current in a sealed container filled with an insulating gas. The switchgear includes a fixed electrode fixed in the sealed container and a movable electrode movably installed in the sealed container. When in a closed state in which the movable electrode and the fixed electrode are in contact with each other, the switchgear allows a current to flow therethrough. When in an open state in which the movable electrode is separated from the fixed electrode, the switchgear cuts off the current.

[0003] During the opening operation for shifting from the closed state to the open state, an arc is generated between the movable electrode and the fixed electrode. An arc existing between the movable electrode and the fixed electrode causes a current flow despite the movable electrode and the fixed electrode being not in contact with each other. It is required to quickly extinguish the arc generated between the movable electrode and the fixed electrode during the opening operation.

[0004] A switchgear disclosed in Patent Literature 1 uses air as an insulating medium and includes a negative pressure chamber defined by a tubular movable contact, a piston movable with the movable contact, and a cylinder. The disclosed switchgear is designed to improve arc-extinguishing performance by increasing a suction flow velocity of the air in the vicinity of a creepage surface of a distal end opening of the movable contact under a pressure of the negative pressure chamber during an opening operation of the switchgear.Citation ListPatent Literature

[0005] Patent Literature 1: Japanese Patent Application Laid-open No. H5-250966Summary of InventionProblem to be solved by the Invention

[0006] For the switchgear disclosed in Patent Literature 1, the distal end of the movable contact opens in the same direction as the opening / closing operation axial direction of the movable contact. The gas sucked into the opening also flows in the axial direction of the switchgear. In addition, the arc generated between the face-to-face ends of the fixed and movable contacts at the time of current cut-off occurs in the same direction as the opening / closing operation axis of the movable contact, too. For this reason, only a part of the gas flow generated near the creepage surface of the opening flows near the arc for contribution to cooling the arc. This results in a problem of the failure of most of the gas flow to contribute to the cooling of the arc.

[0007] The present disclosure has been made in view of the above, and an object thereof is to provide a switchgear with improved arc cooling performance.Means to Solve the Problem

[0008] To solve the above problem and achieve the object, a switchgear according to the present disclosure comprises: a sealed container filled with an insulating gas; a fixed electrode installed inside the sealed container; and a movable electrode movably installed inside the sealed container, the movable electrode including a cylinder having a tubular shape, a piston installed in the cylinder, and a movable-side contact having a smaller diameter than the cylinder and fixed to the piston, the movable-side contact having a vent hole formed therein, the vent hole interconnecting a puffer chamber and a space inside the movable-side contact, the puffer chamber being a space formed between the cylinder and the movable-side contact. The switchgear further comprises a cross-flow forming portion to allow a gas flow to have a component in a direction orthogonal to a central axis of the movable-side contact, the gas flow being sucked into the movable-side contact during an opening operation of shifting from a closed state in which the movable electrode is in contact with the fixed electrode to an open state in which the movable electrode is separated from the fixed electrode.Effects of the Invention

[0009] The present disclosure can achieve the effect of obtaining a switchgear with improved arc cooling performance.Brief Description of Drawings

[0010] FIG. 1 is a cross-sectional view of a switchgear according to the first embodiment. FIG. 2 is a cross-sectional view of a switchgear according to the first embodiment. FIG. 3 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the first embodiment. FIG. 4 is a perspective view of the support base of the switchgear according to the first embodiment. FIG. 5 is a diagram illustrating an arc-extinguishing operation during the opening operation of the switchgear according to the first embodiment. FIG. 6 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the second embodiment. FIG. 7 is a schematic diagram of a gas flow generated in the movable electrode of the switchgear according to the second embodiment. FIG. 8 is a perspective view of a cross-flow forming portion of the switchgear according to the third embodiment. FIG. 9 is a side view of the cross-flow forming portion of the switchgear according to the third embodiment. FIG. 10 is a view schematically illustrating a gas flow of the switchgear according to the third embodiment. FIG. 11 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the fourth embodiment. FIG. 12 is a cross-sectional view of a switchgear according to the fifth embodiment. FIG. 13 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the fifth embodiment. FIG. 14 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the sixth embodiment. FIG. 15 is a diagram illustrating lines of magnetic force generated by the permanent magnet of the movable electrode of the switchgear according to the sixth embodiment. FIG. 16 is a diagram illustrating an opening operation of the switchgear according to the sixth embodiment. Description of Embodiments

[0011] A switchgear according to embodiments will be hereinafter described in detail based on the drawings. The present invention is not limited to the embodiments.First Embodiment.

[0012] FIGS. 1 and 2 are cross-sectional views of a switchgear according to the first embodiment. A switchgear 100 includes a sealed container 1 filled with an insulating gas, a fixed electrode 5 installed inside the sealed container 1, and a movable electrode 3 movably installed inside the sealed container 1. Note that FIG. 1 illustrates a closed state in which the movable electrode 3 and the fixed electrode 5, which will be described later, are in contact with each other, and FIG. 2 illustrates an open state in which the movable electrode 3 and the fixed electrode 5 are separated from each other.

[0013] The fixed electrode 5 includes a fixed-side contact 51 having a tubular shape. The movable electrode 3 includes a movable-side contact 31 having a tubular shape and thinner than the fixed-side contact 51. The outer diameter of the movable-side contact 31 is slightly larger than the inner diameter of the fixed-side contact 51, such that the movable-side contact 31 and the fixed-side contact 51 are in close contact with each other under the elastic force of each of the movable-side contact 31 and the fixed-side contact 51 when the switchgear is in the closed state. An example discussed herein is where the fixed-side contact 51 has a tubular shape having a larger diameter than the movable-side contact 31, but the fixed-side contact 51 may be of a tulip type. The "closed state" means that the movable-side contact 31 and the fixed-side contact 51 are in contact with each other while the "open state" means that the movable-side contact 31 is separated from the fixed-side contact 51.

[0014] The switchgear 100 is closed as the movable electrode 3 comes into contact with the fixed electrode 5, and is opened as the movable electrode 3 is separated from the fixed electrode 5.

[0015] In addition to the movable-side contact 31, the movable electrode 3 includes a cylinder 32, a piston 33, and a rod 34. The cylinder 32 has a tubular shape having a larger diameter than the movable-side contact 31. The piston 33 is installed inside the cylinder 32. The piston 33 is fixed to the rod 34. The rod 34, which is connected to an operation rod of an operation device (not illustrated), moves the piston 33 under a driving force transmitted from the operation device (not illustrated). Upon the movement of the piston 33, the movable-side contact 31 moves inside the cylinder 32.

[0016] FIG. 3 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the first embodiment. The movable-side contact 31 includes a first portion 311 that comes into and out of contact with the fixed-side contact 51, and a second portion 312 that supports the first portion 311. As illustrated in FIGS. 1 and 2, the second portion 312 is fixed to the piston 33. Installed in the movable-side contact 31 are a support base 35, a first tube 371, and a second tube 372. The support base 35 is formed of a non-magnetic body such as a non-magnetic metal or an insulator. The first tube 371 is formed of a magnetic body, and the second tube 372 is formed of a non-magnetic body.

[0017] FIG. 4 is a perspective view of the support base of the switchgear according to the first embodiment. The support base 35 includes a holding portion 351 and a support leg 352. The holding portion 351, which has a tubular shape, allows a bar-shaped member 39 to fit thereinto. The support leg 352 extends radially outwardly from an outer circumferential surface 351a of the holding portion 351.

[0018] As illustrated in FIG. 3, the support base 35 is fixed in the movable-side contact 31 with the support leg 352 sandwiched between the first tube 371 and the second tube 372. The first tube 371 and the second tube 372 have slits formed therein for the support leg 352 to fit into the slits to thereby prevent rotation of support base 35 about the axis of the movable-side contact 31.

[0019] The bar-shaped member 39 is formed of a non-magnetic body. The bar-shaped member 39 has an insulating layer 40 provided on a surface thereof. The insulating layer 40 is a non-magnetic body serving as a core material having an insulating tape wound thereon. Alternatively, the insulating layer 40 is a molded insulator. The bar-shaped member 39 includes a fixed-side end having a cross-flow forming portion 42 formed thereat. The cross-flow forming portion 42 has a frustum shape having a diameter that uniformly increases toward the fixed-side contact 51 along the axial direction of the movable-side contact 31. That is, the cross-flow forming portion 42 includes an outer circumferential surface 421. The outer circumferential surface 421 is a linearly tapered surface inclined relative to the central axis of the movable-side contact 31 such that a distance between the outer circumferential surface 421 and the central axis of the movable-side contact 51 uniformly increases toward the end portion 422 facing the fixed-side contact 31.

[0020] A gap between the bar-shaped member 39 and the movable-side contact 31 is a nozzle portion 60 through which the insulating gas passes. The bar-shaped member 39 is installed such that the cross-flow forming portion 42 protrudes toward the fixed-side contact 51 more than the fixed-side end of the movable-side contact 31. Alternatively, the bar-shaped member 39 is installed such that the fixed-side end of the movable-side contact 31 and the cross-flow forming portion 42 are flush with each other.

[0021] The second portion 312 of the movable-side contact 31 has a radially extending vent hole 312a formed therethrough. Formed between the cylinder 32 and the movable-side contact 31 is a puffer chamber 41 that varies in volume with the movement of the piston 33. The volume of the puffer chamber 41 decreases during the closing operation for shifting from the open state to the closed state while the volume of the puffer chamber 41 increases during the opening operation for shifting from the closed state to the open state.

[0022] When the volume of the puffer chamber 41 increases, the gas in the sealed container 1 is sucked from the opening of the fixed-side end of the movable-side contact 31, thereby generating a gas flow in the nozzle portion 60 in the gap between the movable-side contact 31 and the bar-shaped member 39.

[0023] FIG. 5 is a diagram illustrating an arc-extinguishing operation during the opening operation of the switchgear according to the first embodiment. FIG. 5 illustrates the arc-extinguishing operation during the opening operation in the cross section of the movable electrode 3. In FIG. 5, a gas flow generated by an increase in the volume of the puffer chamber 41 is indicated by dashed-dotted line arrows. When the movable-side contact 31 is separated from the fixed-side contact 51 during the opening operation, an arc 70 is generated between the movable-side contact 31 and the fixed-side contact 51. In FIG. 5, the arc 70 is generated at the position P. The arc 70 generated between the movable-side contact 31 and the fixed-side contact 51 is sucked into the movable-side contact 31 by the gas flow generated in the nozzle portion 60 as the volume of the puffer chamber 41 increases. In FIG. 5, the arc 70 is moved from the position P to the position Q by the gas flow generated in the nozzle portion 60.

[0024] Since the bar-shaped member 39 having the cross-flow forming portion 42 formed therein is disposed in the opening of the movable-side contact 31, the insulating gas, which is to be sucked into the nozzle portion 60, provides a gas stream outside the tube of the movable-side contact 31, the gas stream including a radial component directed toward the central axis of the movable-side contact 31. The radial component orthogonal to the axial direction of the central axis of the movable-side contact 31 decreases as the insulating gas enters the inside of the tube of the movable-side contact 31, such that the insulating gas changes into a stream parallel to the axial direction. The gas flow of the insulating gas outside the tube of the movable-side contact 31 is a stream intersecting the arc 70. Thus, a low-temperature gas flow not heated by the arc 70 is blown to the arc 70 outside the tube of the movable-side contact 31, such that the cooling of the arc 70 is promoted to thereby improve the arc-extinguishing performance.

[0025] Since the insulating layer 40 is formed on the surface of the bar-shaped member 39, the insulator forming the insulating layer 40 is evaporated by the heat of the arc 70 into an insulating gas when the arc 70 comes into contact with the insulating layer 40 on the surface of the bar-shaped member 39. The insulating gas generated from the insulating layer 40 on the surface of the bar-shaped member 39 is mixed into the arc 70, such that the arc 70 is further cooled and easily extinguished. If the insulating layer 40 is consumed by the arc 70, the bar-shaped member 39 is removed from the support base 35 for winding of an insulating tape thereon or replacement with another bar-shaped member 39 to thereby restore the pre-consumption state.

[0026] The switchgear 100 according to the first embodiment generates a gas flow including a radial component orthogonal to the axial direction of the central axis of the movable-side contact 31 at the fixed-side opening of the movable-side contact 31, so that the gas flow can cross the arc 70, which can improve the cooling performance of the arc 70. Thus, even when dry air is used as the insulating gas filled in the sealed container 1, the switchgear 100 according to the first embodiment can obtain cut-off performance satisfying the required opening and closing duties.

[0027] In the above description, the outer circumferential surface 421 of the cross-flow forming portion 42 is a linearly tapered surface, but the outer circumferential surface 421 of the cross-flow forming portion 42 may be a parabolic tapered surface or a logarithmic tapered surface. In a case where the outer circumferential surface 421 of the cross-flow forming portion 42 is a parabolic tapered surface or a logarithmic tapered surface, a gas flow having a high ratio of a component orthogonal to the axial direction of the movable-side contact 31 can be generated outside the tube of the movable-side contact 31, so that the arc-extinguishing performance of the arc 70 can be further improved. In addition, by forming the cross-flow forming portion 42 in a T shape in a side view, the ratio of the component orthogonal to the axial direction of the gas flow generated outside the tube of the movable-side contact 31 can be further increased. However, as the flow path of the gas flow is bent, the flow path resistance increases and the flow velocity of the gas flow tends to decrease. Therefore, from the viewpoint of preventing an increase in the flow path resistance, the outer circumferential surface 421 of the cross-flow forming portion 42 is preferably a tapered surface.Second Embodiment.

[0028] FIG. 6 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the second embodiment. The switchgear 100 according to the second embodiment is different from the switchgear 100 according to the first embodiment in that the cross-flow forming portion 42 formed at the fixed-side end of the bar-shaped member 39 has a teardrop shape in a side view.

[0029] FIG. 7 is a schematic diagram of a gas flow generated in the movable electrode of the switchgear according to the second embodiment. Since the cross-flow forming portion 42 has a teardrop shape in a side view, no gas pool of the insulating gas heated by the arc 70 is formed in a region 11 adjacent to the fixed side of the cross-flow forming portion 42. Thus, the switchgear 100 according to the second embodiment can prevent the recurring of the arc 70 resulting from the high-temperature insulating gas staying near the movable-side contact 31.Third Embodiment.

[0030] FIG. 8 is a perspective view of the cross-flow forming portion of the switchgear according to the third embodiment. FIG. 9 is a side view of the cross-flow forming portion of the switchgear according to the third embodiment. The switchgear 100 according to the third embodiment is different from the switchgear 100 according to the first embodiment in that the cross-flow forming portion 42 has a windmill shape. The cross-flow forming portion 42 of the switchgear 100 according to the third embodiment has a windmill shape having a truncated cone having a spiral-shaped groove 423 formed thereon. The groove 423 has its side surface 424. The side surface 424 is an inclined surface whose position about the axis changes along the axial direction of the central axis of the movable-side contact 31.

[0031] FIG. 10 is a view schematically illustrating a gas flow of the switchgear according to the third embodiment. For the cross-flow forming portion 42 having a windmill shape, the side surface of the groove 423 rectifies the gas flow into a spiral gas flow around the central axis of the movable-side contact 31 in the tube of the movable-side contact 31.

[0032] Since the gas flow in the tube of the movable-side contact 31 is a spiral stream, a low-temperature gas flow is blown to the arc 70 even inside the movable-side contact 31, which improves the arc-extinguishing performance.Fourth Embodiment.

[0033] FIG. 11 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the fourth embodiment. The switchgear 100 according to the fourth embodiment is different from the switchgear 100 according to the first embodiment in lacking the bar-shaped member 39 and including the support base 35 supporting the cross-flow forming portion 42.

[0034] Similarly to the switchgear 100 according to the first embodiment, the switchgear according to the fourth embodiment generates a gas flow including a radial component orthogonal to the axial direction of the central axis of the movable-side contact 31 at the fixed-side opening of the movable-side contact 31, so that the gas flow can cross the arc, which can improve the cooling performance of the arc 70. Therefore, even when dry air is used as the insulating gas filled in the sealed container 1, the switchgear 100 according to the fourth embodiment can obtain cut-off performance satisfying the required opening and closing duties.Fifth Embodiment.

[0035] FIG. 12 is a cross-sectional view of a switchgear according to the fifth embodiment. FIG. 13 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the fifth embodiment. The switchgear 100 according to the fifth embodiment does not include the support base 35, the first tube 371, the second tube 372, and the bar-shaped member 39. Further, the movable-side contact 31 is not divided into the first portion 311 and the second portion 312, but is an integrally formed one. The other configurations are similar to those of the switchgear 100 according to the first embodiment.

[0036] The movable-side contact 31 has a cross-flow forming portion 313 formed at the fixed-side end thereof. The cross-flow forming portion 313 includes a tapered surface such that the distance between the tapered surface and the central axis of the movable-side contact 31 uniformly increases toward the fixed-side contact 51 along the axial direction of the movable-side contact 31. That is, the cross-flow forming portion 313 includes a surface inclined relative to the central axis of the movable-side contact 31.

[0037] The gas flow sucked into the movable-side contact 31 during the opening operation flows along the tapered surface of the cross-flow forming portion 313. The component directed toward the central axis of the movable-side contact 31 decreases as the gas flow is sucked into the movable-side contact 31, such that the gas flow changes into a stream parallel to the axial direction of the movable-side contact 31.

[0038] Similarly to the switchgear 100 according to the first embodiment, the switchgear 100 according to the fifth embodiment generates a gas flow including a radial component orthogonal to the axial direction of the central axis of the movable-side contact 31 at the fixed-side opening of the movable-side contact 31, so that the gas flow can cross the arc, which can improve the cooling performance of the arc 70. Therefore, even when dry air is used as the insulating gas filled in the sealed container 1, the switchgear 100 according to the fifth embodiment can obtain cut-off performance satisfying the required opening and closing duties.Sixth Embodiment.

[0039] FIG. 14 is an enlarged view of a movable portion of the movable electrode of the switchgear according to the sixth embodiment. In the switchgear 100 according to the sixth embodiment, the bar-shaped member 39 is formed of a magnetic body, and the support base 35 has a permanent magnet 36 fitted therein. The bar-shaped member 39 is installed in close contact with the permanent magnet 36 on the fixed side. A cap 43 is installed at the fixed-side end of the bar-shaped member 39. The cap 43 has a frustum shape having a diameter that uniformly increases from the movable-side contact 31 toward the fixed-side contact 51 along the axial direction of the movable-side contact 31. That is, the cap 43 includes an outer circumferential surface 431. The outer circumferential surface 431 is a linearly tapered surface inclined with respect to the axial direction such that a diameter of the outer circumferential surface 431 uniformly increases toward an end 432 facing the fixed-side contact 51. In the sixth embodiment, the cross-flow forming portion 42 having a surface inclined with respect to the central axis of the movable-side contact 31 is defined by the cap 43.

[0040] The switchgear 100 according to the sixth embodiment has the holding portion 351. The holding portion 351 has an opening on the side of the fixed-side contact 51 in the direction of arrangement of the movable-side contact 31 and the fixed-side contact 51. The holding portion 351 has an opening on the side of the movable-side contact 31 in the direction of arrangement of the movable-side contact 31 and the fixed-side contact 51. The opening on the side of the fixed-side contact 51 is smaller than the permanent magnet 36. The opening on the side of the movable-side contact 31 is larger than the permanent magnet 36. The permanent magnet 36 fits in the holding portion 351 from the opening on the side of the movable-side contact 31 in the direction of arrangement of the movable-side contact 31 and the fixed-side contact 51. The opening of the holding portion 351 on the side of the movable-side contact 31 in the direction of arrangement of the movable-side contact 31 and the fixed-side contact 51 is closed by a lid 38 formed of a magnetic body, so that the permanent magnet 36 does not fall off from the holding portion 351. The bar-shaped member 39 is fit into the fixed-side opening of the holding portion 351, and the bar-shaped member 39 is in close contact with the permanent magnet 36 as described above.

[0041] FIG. 15 is a diagram illustrating lines of magnetic force generated by the permanent magnet of the movable electrode of the switchgear according to the sixth embodiment. While the bar-shaped member 39 and the lid 38 are formed of a magnetic body, the support base 35 is formed of a non-magnetic body. As a result, lines of magnetic force generated by the permanent magnet 36 indicated by arrows in FIG. 15 are more likely to pass through the bar-shaped member 39 and the lid 38 and less likely to pass through the support leg 352. In addition, the first tube 371 is formed of a magnetic body, the second tube 372 is formed of a non-magnetic body, and the bar-shaped member 39 is longer than the lid 38. As a result, the magnetic field which the permanent magnet 36 generates on the side having the fixed-side contact 51 installed thereon is stronger than the magnetic field which the permanent magnet 36 generates on the side opposite to the side having the fixed-side contact 51 installed thereon. The lines of magnetic force are more likely to pass through the bar-shaped member 39 when the bar-shaped member 39 is in close contact with the permanent magnet 36. Even when there is a magnetic gap between the bar-shaped member 39 and the permanent magnet 36, the magnetic field which the permanent magnet 36 generates on the side having the fixed-side contact 51 installed thereon can be made stronger than the magnetic field which the permanent magnet 36 generates on the side opposite to the side having the fixed-side contact 51 installed thereon. In addition, the first tube 371 may be a non-magnetic body. Even when the first tube 371 is formed of a non-magnetic body, the bar-shaped member 39 is installed adjacent to the fixed side of the permanent magnet 36. As a result, the magnetic field which the permanent magnet 36 generates on the side having the fixed-side contact 51 installed thereon can be made stronger than the magnetic field which the permanent magnet 36 generates on the side opposite to the side having the fixed-side contact 51 installed thereon.

[0042] FIG. 16 is a diagram illustrating an opening operation of the switchgear according to the sixth embodiment. When the arc 70 generated during the opening operation approaches the bar-shaped member 39, the arc 70 is captured by the magnetic field of the permanent magnet 36. Since the lines of magnetic force passing out of the permanent magnet 36 through the bar-shaped member 39 include a component intersecting the arc 70 generated between the movable-side contact 31 and the fixed-side contact 51, the arc 70 rotates in the magnetic field the permanent magnet 36 generates. In FIG. 16, the arc 70 captured by the magnetic field the permanent magnet 36 generates is drawn rotating, such that the arc moves from the position B to the position C, and further from the position C to the position D. During the opening operation, the arc 70 generated between the movable-side contact 31 and the fixed-side contact 51 is drawn into the movable-side contact 31 as the arc 70 rotates, such that the arc 70 is extended during which the arc 70 is cooled and extinguished.

[0043] The switchgear 100 according to the sixth embodiment generates a gas flow including a radial component orthogonal to the axial direction of the central axis of the movable-side contact 31 at the fixed-side opening of the movable-side contact 31, and in addition, extends the arc 70 under the action of the magnetic field generated by the permanent magnet 36, so that the arc-extinguishing performance of the arc 70 can be further improved.

[0044] In the switchgear 100 according to the sixth embodiment, the cross-flow forming portion 42 may have a teardrop shape or a windmill shape. In the case where the cross-flow forming portion 42 has a windmill shape, the switchgear 100 is used to cut off the direct current, and the rotation direction of the arc 70 by the magnetic field the permanent magnet 36 generates and the rotation direction of the gas flow by the cross-flow forming portion 42 are made opposite to each other, so that the low-temperature insulating gas not heated by the arc 70 can be blown to the arc 70 as the gas flow, and the arc-extinguishing performance can be further improved.

[0045] The configurations described in the above-mentioned embodiments indicate examples. The configurations can be combined with another well-known technique, and some of the configurations can be omitted or changed in a range not departing from the gist.Reference Signs List

[0046] 1 sealed container; 3 movable electrode; 5 fixed electrode; 11 region; 31 movable-side contact; 32 cylinder; 33 piston; 34 rod; 35 support base; 36 permanent magnet; 38 lid; 39 bar-shaped member; 40 insulating layer; 41 puffer chamber; 42, 313 cross-flow forming portion; 43 cap; 51 fixed-side contact; 60 nozzle portion; 70 arc; 100 switchgear; 311 first portion; 312 second portion; 312a vent hole; 351 holding portion; 351a, 421, 431 outer circumferential surface; 352 support leg; 371 first tube; 372 second tube; 422, 432 end; 423 groove; 424 side surface.

Claims

1. A switchgear comprising: a sealed container filled with an insulating gas; a fixed electrode installed inside the sealed container; a movable electrode movably installed inside the sealed container, the movable electrode including a cylinder having a tubular shape, a piston installed in the cylinder, and a movable-side contact having a smaller diameter than the cylinder and fixed to the piston, the movable-side contact having a vent hole formed therein, the vent hole interconnecting a puffer chamber and a space inside the movable-side contact, the puffer chamber being a space formed between the cylinder and the movable-side contact; and a cross-flow forming portion to allow a gas flow to have a component in a direction orthogonal to a central axis of the movable-side contact, the gas flow being sucked into the movable-side contact during an opening operation of shifting from a closed state in which the movable electrode is in contact with the fixed electrode to an open state in which the movable electrode is separated from the fixed electrode.

2. The switchgear according to claim 1, wherein the cross-flow forming portion is disposed on the central axis of the movable-side contact.

3. The switchgear according to claim 2, comprising: a support base installed in the movable-side contact; and a bar-shaped member installed adjacent to a side where the fixed electrode is disposed with respect to the support base, wherein the cross-flow forming portion is provided at a distal end of the bar-shaped member.

4. The switchgear according to claim 3, comprising a permanent magnet fixed to the support base, wherein the bar-shaped member is formed of a magnetic body.

5. The switchgear according to any one of claims 1 to 4, wherein the cross-flow forming portion has a shape having a diameter that increases along a direction from the movable electrode toward the fixed electrode in an axial direction of the central axis of the movable-side contact.

6. The switchgear according to any one of claims 1 to 4, wherein the cross-flow forming portion has a teardrop shape as viewed from a direction perpendicular to an axial direction of the movable-side contact.

7. The switchgear according to any one of claims 1 to 4, wherein the cross-flow forming portion has a windmill shape including an inclined surface whose position about an axis changes along an axial direction of the central axis of the movable-side contact.

8. The switchgear according to claim 1, wherein the cross-flow forming portion is a tapered surface provided at an edge of an opening of the movable-side contact, the tapered surface increasing in distance from the central axis of the movable-side contact along a direction from the movable electrode toward the fixed electrode in an axial direction of the central axis of the movable-side contact.

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