vacuum valve

Abstract

This provides a simpler way to prevent discharge paths in vacuum valves. [Solution] The vacuum valve according to the embodiment comprises an insulating container having openings at both ends, a vacuum container having a sealing fitting having an opening and each being joined via the openings and joints, a pair of electrodes detachably arranged opposite each other inside the vacuum container, an electric field mitigation shield provided to cover the ends of the insulating container, the sealing fittings and joints, an insulating coating layer provided on at least a portion of the surface of the electric field mitigation shield, and an open portion including a void provided in at least a portion of the region between the ends of the insulating container, the sealing fittings and joints and the electric field mitigation shield, This includes an insulating member partially provided in the open portion.

Description

Technical Field

[0001] Embodiments of the present invention relate to a vacuum valve.

Background Art

[0002] At the end of the sealing fitting of the vacuum valve used in the switchgear, there is a high electric field area called a triple junction. Here, three media, a cylindrical insulator, a sealing fitting, and air, are in contact at a single point, and a high electric field is generated when a voltage is applied to the sealing fitting. As a method for alleviating the electric field in the high electric field area, a metal electric field relaxation shield can be arranged. As a product using the vacuum valve provided with this electric field relaxation shield, there is a cubicle type gas-insulated switchgear (C-GIS) using SF6 gas. However, since SF6 gas is a greenhouse gas and is expected to be regulated in the future, in recent years, C-GIS in which SF6 gas is replaced with an alternative gas has been developed. As an alternative gas, for example, there is dry air, but its insulation performance is only about 1 / 3 compared to SF6 gas, and many other alternative gases also have inferior insulation performance compared to SF6 gas, and it is difficult to achieve insulation performance (dielectric breakdown voltage) equivalent to that of SF6 gas only with alternative gases. Therefore, the combined use of solid insulators has been considered, and as one of them, in order to improve the dielectric breakdown voltage of a metal electric field relaxation shield, its surface is coated with resin. However, with only the above countermeasures, resin-coated portions inside the electric field relaxation shield, for example, fixing portions such as screw holes and screws of the electric field relaxation shield for fixing to the sealing fitting, metal exposed portions such as the sealing fitting, and triple junction portions, etc., discharge, making it difficult to improve the dielectric breakdown voltage. On the other hand, there is also a method of molding the entire vacuum valve and the electric field relaxation shield with resin, but it requires a mold, etc., the cost is high, and it is difficult to coat it with resin without defects due to the complex structure. For these reasons, there is a need for a vacuum valve that can more simply suppress discharge and improve insulation performance.

Prior Art Documents

[0003] [Patent Document 1] Japanese Patent Publication No. 2009-193734 [Patent Document 2] Japanese Patent Publication No. 2008-99384 [Patent Document 3] Japanese Patent Publication No. 2012-243581 [Patent Document 4] Japanese Patent Publication No. 2016-219175 [Overview of the project] [Problems that the invention aims to solve]

[0004] The embodiments of the present invention aim to provide a simpler way to prevent discharge in vacuum valves. [Means for solving the problem]

[0005] According to the embodiment, an insulating container having openings at both ends, and a vacuum container having a sealing fitting having an opening, each joined to the openings via a joint, A pair of electrodes are detachably arranged facing each other within the vacuum container, The end of the insulating container, the sealing fitting, and the joint are provided to cover the electric field mitigation shield, An insulating coating layer provided on at least a portion of the surface of the electric field relaxation shield, An open portion including a gap is provided in at least a part of the region between the end of the insulating container, the sealing fitting, the joint, and the electric field mitigation shield, A vacuum valve is provided, characterized in that it includes an insulating member partially provided in the opening. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic cross-sectional view showing a first example of a vacuum valve according to an embodiment. [Figure 2] This is a magnified view of the fixed electrode side of Figure 1. [Figure 3] This is a partially enlarged view of the fixed electrode side of a second example of a vacuum valve according to the embodiment. [Figure 4] This is a partially enlarged view of the fixed electrode side of a third example of a vacuum valve according to the embodiment. [Figure 5] This is a partially enlarged view of the fixed electrode side of a fourth example of a vacuum valve according to the embodiment. [Figure 6] This is a partially enlarged view of the fixed electrode side of a fifth example of a vacuum valve according to the embodiment. [Figure 7] This is a partially enlarged view of the fixed electrode side of the sixth example of a vacuum valve according to the embodiment. [Figure 8] This is a partially enlarged view of the fixed electrode side of the seventh example of the vacuum valve according to the embodiment. [Figure 9] This is a partially enlarged view of the fixed electrode side of the eighth example of a vacuum valve according to the embodiment. [Figure 10] This is a partially enlarged view of the fixed electrode side of the ninth example of a vacuum valve according to the embodiment. [Figure 11] This is a partially enlarged view of the fixed electrode side of the ninth example of a vacuum valve according to the embodiment. [Modes for carrying out the invention]

[0007] The vacuum valve according to the embodiment includes an insulating container having openings at both ends, a vacuum container having a sealing fitting having an opening and being joined to the openings via a joint, a pair of electrodes detachably arranged opposite each other inside the vacuum container, an electric field mitigation shield provided to cover the ends of the insulating container, the sealing fitting and the joint, an insulating coating layer provided on at least a portion of the electric field mitigation shield, an open portion including a gap provided in at least a portion of the region between the ends of the insulating container, the sealing fitting and the joint and the electric field mitigation shield, and an insulating member partially provided in the open portion.

[0008] Unlike resin-molded vacuum valves in which the outer periphery of the vacuum vessel and electric field mitigation shield is filled with an insulating resin layer, the vacuum valve according to this embodiment is not resin-molded. Therefore, it has an open portion in at least part of the region between the end of the insulating vessel, the sealing fitting, and the joint and the electric field mitigation shield, and this open portion has a void. Although the open portion includes areas where discharge is likely to occur, such as exposed metal and triple junction portions, according to this embodiment, by partially providing an insulating material in the open portion, it is possible to block the discharge path in the open portion and prevent discharge. This makes it possible to improve the dielectric breakdown voltage. Furthermore, the vacuum valve according to this embodiment does not require the formation of a resin mold or the use of a mold for that purpose, as it only requires partially providing an insulating material in the open portion, and is therefore low-cost. The embodiment will be described below with reference to the drawings.

[0009] Furthermore, the disclosure is merely an example, and any modifications that can be easily conceived by a person skilled in the art while maintaining the spirit of the invention are naturally included within the scope of the present invention. In addition, the drawings may schematically represent the width, thickness, shape, etc. of each part in order to clarify the explanation, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each drawing, elements similar to those described above in previously shown drawings are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0010] Figure 1 shows a schematic cross-sectional view representing a first example of a vacuum valve according to an embodiment. As shown in the figure, the vacuum valve 105 has openings 10a and 10b at both ends, and includes a cylindrical ceramic container 10 as an insulating container made of, for example, alumina porcelain or the like, a fixed-side sealing fitting 11 joined to one of the openings 10a via a joint portion 31, and a movable-side sealing fitting 12 joined to the other opening 10b via a joint portion 32. The inside of the vacuum container 100 is maintained in a vacuum state. The fixed-side sealing fitting 11 is provided with a central opening, and a fixed-side current-carrying shaft 13 is fixedly penetrated therethrough. A fixed-side contact 14 is fixed to the end of the fixed-side current-carrying shaft 13 inside the ceramic container 10. Opposite to the fixed-side contact 14, a pair of separable movable-side contacts 15 are fixed to the end of a movable-side current-carrying shaft 16 that movably penetrates a central opening provided in the movable-side sealing fitting 12. In this movable-side current-carrying shaft 16, the portion on the side of the movable-side sealing fitting 12 from the central portion is a portion led out of the ceramic container 10, and a telescopic cylindrical bellows 17 for airtight sealing is disposed on that portion. The free end 101 of the bellows 17 is sealed to the central portion of the movable-side current-carrying shaft 16, and the fixed end 102 is sealed to the central opening of the movable-side sealing fitting 12. A cylindrical arc shield 18 is provided around the fixed-side contact 14 and the movable-side current-carrying shaft 16. The arc shield is a conductor and can be formed of a metal material such as stainless steel, for example.

[0011] The vacuum valve 105 further includes, for example, a bowl-shaped fixed-side electric-field relaxation shield 19-1 provided so as to surround the fixed-side sealing fitting 11 that forms the outer periphery of the vacuum container 100. The fixed-side electric-field relaxation shield 19-1 is fixed to the fixed-side current-carrying shaft 13 and is separated from the vacuum container 100 and its components such as the fixed-side sealing fitting 11 and the ceramic container 10. An open portion 33 including a gap is provided in the region therebetween. An insulating member 34 is provided in the open portion 33 partially. The insulating member 34 can be provided, for example, so as to fill the open portion 33 near the edge portion 19-1a of the electric-field relaxation shield 19-1.

[0012] In addition, the vacuum valve 105 can further include a bowl-shaped movable-side electric field relaxation shield 20-1 provided so as to surround the movable-side sealing fitting 12 as well. The movable-side electric field relaxation shield 20-1 is fixed to the movable-side current-carrying shaft 16 and is separated from the vacuum vessel 100 and its components such as the movable-side sealing fitting 12, the ceramic vessel 10, etc. An open portion 37 including a gap is provided in the region therebetween. An insulating member 36 is partially provided in the open portion 37. The insulating member 36 can be provided, for example, so as to fill the open portion 37 near the edge portion 20-1a of the electric field relaxation shield 20-1. An insulating atmosphere can be provided around the vacuum vessel 100 provided with the fixed-side electric field relaxation shield 19-1 and the movable-side electric field relaxation shield 20-1. At this time, the gaps in the open portions 33 and 37 can be made into an insulating atmosphere.

[0013] Fig. 2 shows a partially enlarged view of the fixed electrode side of Fig. 1. As shown in the drawing, the electric field relaxation shield 19-1 has a conductive region 19b containing, for example, metal or conductive resin, and an insulating region 19a containing an insulating resin provided on at least a part of the surface of the conductive region 19b. Here, the conductive region 19b is the main body of the fixed-side electric field relaxation shield 19-1 and has a similar bowl shape. An insulating coating layer containing an insulating resin is provided as the insulating region 19a from the outer surface 19b-1 of the conductive region 19b to the inner surface (inner side surface) 19b-2 of the body portion for the purpose of improving the insulation performance. As a result, the breakdown voltage increases to a certain extent. However, the inner surface 19b-3 of the waist portion of the conductive region 19b exposes the conductive region 19b. As a portion where the conductive region 19b is exposed, fixing portions such as screw holes and screws of the electric field relaxation shield for fixing to the fixed-side sealing fitting 11 are also provided on the inner surface 19b-3.

[0014] The rim portion 19-1a of the electric field mitigation shield 19-1 extends beyond the joint 31 toward the fixed-side contact 14 so as to sufficiently cover the triple junction 30 at the joint 31 between the fixed-side sealing fitting 11 and the opening of the ceramic container 10. Here, the triple junction 30 is a triple point formed by, for example, the ceramic of the ceramic container 10, the metal of the fixed-side sealing fitting 11, and the insulator of the insulating atmosphere, resulting in a relatively high electric field and becoming the starting point for dielectric breakdown. By covering it with the electric field mitigation shield 19-1, the electric field of the triple junction 30 can be mitigated. Furthermore, in the figure, the high-electric-field portion 30-2 is a triple point formed by, for example, the end of the inner surface 19b-2, the exposed portion of the conductive region 19b at the end of the inner surface 19b-3 of the waist of the conductive region 19b, and the insulator in the insulating atmosphere. If there is an open space between the end of the inner surface 19b-2 and the rim portion 19-1a of the electric field mitigation shield 19-1, a discharge path as shown by arrow 39 will be formed with respect to the high-electric-field portion 30-1, and discharge may occur. Also, a discharge path as shown by arrow 38 will be formed with respect to the high-electric-field portion 30-1 near the outer circumference of the rim portion of the fixed-side sealing fitting 11, and discharge may occur.

[0015] In contrast, by providing an insulating member 34 to fill the end of the open portion 33 near the rim 19-1a of the electric field mitigation shield 19-1, it becomes possible to block the discharge path indicated by arrows 38 and 39, thereby preventing the occurrence of discharge. Similarly, by providing an insulating member 36 to fill the end of the open portion 37 near the rim 20-1a of the electric field mitigation shield 20-1, it becomes possible to block the discharge path that may occur within the open portion 37, thereby preventing the occurrence of discharge. In this way, by partially providing insulating members 34 and 36 in the open portions 33 and 37, which include air gaps in at least a part of the region between the end of the insulating container 10, the sealing fittings 11 and 12, and the joints 31 and 32, and the electric field mitigation shields 19-1 and 20-1, the discharge paths of the open portions 33 and 37 can be blocked, and the electric field at the high-electric field location of the vacuum valve 105 can be mitigated. Furthermore, this can prevent discharge of the vacuum valve 105 and improve the dielectric breakdown voltage.

[0016] To maintain an insulating atmosphere, the vacuum vessel 100, equipped with a fixed-side electric field mitigation shield 19-1 and a movable-side electric field mitigation shield 20-1, can be housed in a case (not shown). Examples of insulating atmospheres include insulating gases such as SF6 gas and dry air. Dry air can be used to avoid the use of greenhouse gases. A high-dielectric-constant region containing a high-dielectric-constant resin can be provided between the conductive region and the insulating region. Examples of conductive regions for the movable electric field relaxation shields 19-1 and 20-1 include metals or conductive resins. Examples of metals that can be used in the conductive regions of the sealing fittings 11, 12, or the movable electric field mitigation shields 19-1, 20-1 include aluminum, iron, copper, or alloys mainly composed of these metals.

[0017] The conductive resins of the movable electric field relaxation shields 19-1 and 20-1 can have an conductivity of, for example, 10^-1 S / m or higher. Examples of conductive resins include those obtained by adding conductive particles to a resin base material such as epoxy resin.

[0018] Examples of resins that can be used as a resin matrix to which particles for imparting conductivity are added, or as a resin coating layer for the movable electric field relaxation shields 19-1 and 20-1, include a group of resins generally called thermosetting resins such as epoxy resin, phenolic resin, melamine resin, urea resin, polyurethane resin, unsaturated polyester resin, polyimide resin, or silicone resin, or a group of resins generally called thermoplastic resins such as polyethylene, polyvinyl chloride, polypropylene, polystyrene, ABS, PMMA (acrylic), PET, polyacetal, polyetheretherketone, fluororesin, polycarbonate, or nylon. As conductive particles, for example, conductive fibrous particles can be used. Conductive fibrous particles have a fibrous aspect ratio with a small particle diameter and long length, and can be arranged to be dispersed in the resin matrix with random orientations.

[0019] Furthermore, as conductive fibrous particles, those with conductivity comparable to that of metals and designed for dispersion in hydrophobic liquids such as resins can be used, and which are composed of a six-membered carbon ring network. Examples of materials composed of a six-membered carbon ring network include carbon nanotubes, carbon nanofibers, carbon microfibers, and graphene. Furthermore, carbon nanofibers can be used as an example of a material composed of a six-membered carbon ring network. Carbon nanofibers have a larger diameter than carbon nanotubes, approximately several hundred nanometers.

[0020] The conductive fibrous particles used in the embodiment can have a volume resistivity of 10^-1 Ωcm or less. Furthermore, the size of the conductive fibrous particles 2 used in the embodiment can be such that the particle diameter is 100 nm to 10 μm, the length is 1 μm to 100 μm, and the aspect ratio (length to particle diameter) is 1.25 to 100. Having the above size of conductive fibrous particles 2 makes it difficult for the particles to aggregate. For example, epoxy resin can be used as the resin that disperses the conductive fibrous particles. When the resin is epoxy resin, polyetheramine can be used as the curing agent.

[0021] As insulating members 34 and 36, for example, a rubber elastic body, a sealing material, an adhesive, or a protruding portion that extends from a part of the insulating coating layer can be used. Examples of rubber elastic materials include natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, silicone rubber, ethylene-vinyl acetate rubber, acrylic rubber, urethane rubber, and fluororubber. Examples of sealing materials include silicone resin, acrylic resin, and urethane resin, while examples of adhesives include organic adhesives mainly composed of organic materials such as epoxy resin, silicone resin, acrylic resin, or phenolic resin, and inorganic adhesives mainly composed of inorganic materials such as alumina, silica, zirconia, and magnesia.

[0022] Examples of the shapes of the insulating members 34 and 36 include O-ring shape, C-ring shape, or cylindrical shape. The insulating members can be of any shape other than those described above, as long as they can be installed to block the discharge path. Furthermore, one or more insulating members 34 and 36 can be installed within the open portions 33 and 37. As the cylindrical ceramic container 10, ceramics that are strong and heat-resistant insulators such as Al2O3, SiO2, ZrO2, AlN, or Si3N4 can be used. The following are various examples of insulating members partially provided in the opening portion of a vacuum valve according to an embodiment. [Examples]

[0023] Example 1 shows an example of a vacuum valve using rubber elastic material as the insulating members 34 and 36 shown in Figures 1 and 2. In Example 1, the rubber elastic material serving as insulating member 34 is provided near the rim 19-1a of the electric field mitigation shield 19-1 in the open portion 33 between the end of the cylindrical insulating container 10 of the vacuum container 100, the sealing fitting 11, and the joint portion 31, and the electric field mitigation shield 19-1. In Example 1, the rubber elastic material serving as insulating member 36 is provided near the rim 20-1a of the electric field mitigation shield 20-1 in the open portion 37 between the end of the insulating container 10 of the vacuum container 100, the sealing fitting 12, and the joint portion 32, and the electric field mitigation shield 20-1.

[0024] The insulating member 34 can have a thickness perpendicular to the axial direction of the insulating container 10 that is greater than the distance of the void perpendicular to the axial direction of the insulating container. For example, when the radial distance (distance perpendicular to the axial direction) t1 between the end of the insulating container 10 and the electric field relaxation shield 19-1, and the radial distance between the end of the insulating container 10 and the electric field relaxation shield 20-1 are both 2 mm, two O-ring shaped rubber elastic bodies having a radial thickness of 3 mm can be used. As the material for the rubber elastic bodies, for example, silicone rubber having a durometer type A (Shore A) hardness of 30 to 50 can be used. For example, if the outer diameter of the insulating container 10 is 150 mm, the O-ring shaped rubber elastic body can have an inner diameter of 148 mm, which is smaller than the outer diameter, and an outer diameter of 154 mm, which is 6 mm larger than the inner diameter.

[0025] The O-ring shaped rubber elastic body can be fitted onto the outer surface of the end of the insulating container 10, for example, surrounding it axially, before the electric field mitigation shield 19-1 and the electric field mitigation shield 20-1 are installed. In order to position the rubber elastic body at a desired location on the outer surface of the end of the insulating container 10, a jig for fixing the rubber elastic body can be attached to the end of the insulating container 10 in advance. Subsequently, the electric field mitigation shield 19-1 can be placed over the sealing fitting 11 via an O-ring shaped rubber elastic body up to the end of the insulating container 10, thereby compressing the O-ring shaped rubber elastic body during installation. As a result, as shown in the figure, the insulating member 34 made of rubber elastic body is compressed and fixed between the vicinity of the opening rim 19-1a of the electric field mitigation shield 19-1 and the end of the insulating container 10.

[0026] Similarly, the electric field mitigation shield 20-1 is attached over the movable side sealing fitting 12 via an O-ring shaped rubber elastic body to the end of the insulating container 10. As a result, as shown in the figure, the insulating member 36 made of rubber elastic body is compressed and fixed between the vicinity of the opening rim 20-1a of the electric field mitigation shield 20-1 and the end of the insulating container 10. The above-mentioned fixtures can be removed after the field mitigation shields 19-1 and 20-1 have been installed. In this case, the thickness of the rubber is compressed by approximately 1 mm at the end of the open section 33, and a force determined simply by the rubber hardness and the amount of compression (1 mm) is generated at the interface between the rubber elastic body and the end of the insulating container 10 and the field mitigation shields 19-1 and 20-1. As a result, the rubber elastic body adheres tightly to the end of the insulating container 10 and the field mitigation shields 19-1 and 20-1. Furthermore, the pressure generated at the interface between the rubber elastic body and the end of the insulating container 10 and the field mitigation shields 19-1 and 20-1 is determined by the generated force and the area in contact between the rubber elastic body and the end of the insulating container 10 and the field mitigation shields 19-1 and 20-1. The higher the pressure generated at this interface, the higher the dielectric breakdown voltage.

[0027] If you want to increase the pressure further, you can increase the force generated by the compression of the rubber. For example, you could make the rubber elastic body so that it is compressed by 2 mm when it is placed with a thickness of 3.5 mm, change the hardness of the rubber to, for example, 60 while keeping the thickness of the rubber elastic body at 3 mm, or significantly change both the thickness and the hardness of the rubber. Furthermore, the length of the insulating members 34 and 36 parallel to the axial direction of the insulating container 10 can be made equal to or smaller than the distance parallel to the axial direction of the regions 33a and 37a where the ends of the insulating container 10 and the electric field relaxation shields 19-1 and 20-1 overlap. In Figure 2, the length of the insulating member 34 parallel to the axial direction of the insulating container 10 is smaller than the distance parallel to the axial direction of the regions 33a and 37a, and it is not in contact with the sealing fitting 11, so the metal surface that could be the starting point of dielectric breakdown is exposed.

[0028] The rubber elastic material is an insulator having rubber elasticity, and is a solid insulator with the flexibility and elasticity of rubber. In Example 1, by applying the rubber elastic material, the rubber elastic material adheres closely to the insulating coating layer 19a covering the end of the insulating container 10 and the electric field relaxation shield 19-1, and to the insulating coating layer 20a covering the end of the insulating container 10 and the electric field relaxation shield 20-1, blocking the discharge path to exposed metal parts such as the sealing fitting 11, and improving the dielectric breakdown voltage compared to placing only the electric field relaxation shields 19-1 and 20-1 in the vacuum valve 1. Possible discharge paths include, for example, a path that goes through the end of the insulating container 10 and the surface of the electric field relaxation shield 19-1 towards exposed metal parts such as the sealing fitting 11, and a path that goes through the end of the insulating container 10 and the surface of the electric field relaxation shield 20-1 towards exposed metal parts such as the sealing fitting 12, as shown by arrows 38 and 39 in Figure 2. The insulating member can be arranged according to the discharge path, and it is not necessary to cover the entire circumference of the insulating container 10 with region 33a. It is also possible to use a rubber elastic body with a shape other than an O-ring, such as a C-ring shape.

[0029] According to this embodiment, since only rubber-elastic insulating members 34 and 36 are arranged, molds are unnecessary and cost increases can be suppressed. Furthermore, the thickness of the rubber elastic body used can be made thicker than the distance between the end of the insulating container 10 and the field mitigation shields 19-1 and 20-1, for example, the distance between the cylindrical insulator 10 and the insulating coating layer 19a of the field mitigation shield 19-1 in Figure 2, for example, the radial distance t1. As a result, when the rubber elastic body is arranged, the rubber elastic body is compressed to the distance between the end of the insulating container 10 and the field mitigation shields 19-1 and 20-1 covered with the insulating coating layers 19a and 20a, generating a compressive load. This causes the vacuum valve 105 and the field mitigation shields 19-1 and 20-1 covered with the insulating coating layers 19a and 20a to be in closer contact, and the dielectric breakdown voltage may increase further. Increasing the thickness of the rubber elastic material increases the resulting compressive load, which in turn increases the pressure at the interface between the rubber elastic material and the end of the insulating container 10, or at the interface between the electric field relaxation shields 19-1 and 20-1 covered with insulating coating layers 19a and 20a. Generally, the dielectric breakdown voltage at an interface increases with increasing pressure at that interface; therefore, the thicker the rubber elastic material, the higher the dielectric breakdown voltage. Furthermore, using a rubber elastic material with higher hardness increases the compressive load generated for the same amount of compression, thus increasing the pressure and thus the dielectric breakdown voltage. However, if the generated compressive load is too high, irreversible deformation or failure may occur, such as deformation, rupture, or delamination of the adhesive between the sealing fitting and the cylindrical insulating material. Therefore, the thickness and hardness of the rubber elastic material must be set to values ​​that are below the compressive load at which such deformation, rupture, or delamination occurs. Thus, according to Example 1, a mold for molding with resin is not required, and costs can be reduced. Furthermore, even if the complex open section is not completely filled with insulating material, the discharge path can be sufficiently blocked by only partially providing insulating material in the open section. [Examples]

[0030] Example 2 shows another example of a vacuum valve using rubber elastic material as insulating members 34 and 36. Figure 3 shows a partially enlarged view of the fixed electrode side of a second example of a vacuum valve according to the embodiment. As shown in Figure 3, the insulating member 35-1 used in Embodiment 2 can have the same configuration as the insulating member 34 in Figure 2, except that its length parallel to the axial direction of the insulating container 10 is equivalent to the distance parallel to the axial direction of the region 33a where the end of the insulating container 10 and the electric field relaxation shield 19-1 overlap. Furthermore, the vacuum valve according to Embodiment 2 can have the same configuration as in Figure 1, except that insulating member 35-1 is used instead of insulating member 34, and insulating member 36 is used instead of insulating member 35-1.

[0031] As a result, the vacuum valve 105, the electric field mitigation shield 19-1 covered with the insulating coating layer 19a, and the electric field mitigation shield 20-1 covered with the insulating coating layer 20a are in closer contact, which can further increase the dielectric breakdown voltage. In addition, a mold for molding with resin is not required, which can lower costs. In Figure 3, the length of the insulating member 34 parallel to the axial direction of the insulating container 10 is the same as the axial direction of the region 33a, and it is not in contact with the sealing fitting 11. Therefore, as in Figure 2, although a metal surface that could be the starting point of dielectric breakdown is exposed, the discharge path can be sufficiently blocked by only partially providing the insulating member in the open portion. [Examples]

[0032] Example 3 shows yet another example of a vacuum valve using a rubber elastic material as an insulating member. Figure 4 shows a partially enlarged view of the fixed electrode side of a third example of a vacuum valve according to the embodiment. As shown in Figure 4, the insulating member 35-2 made of a rubber elastic material used in Example 3 can have the same configuration as the insulating member 34 in Figure 2, except that the length parallel to the axial direction of the insulating container 10 is greater than the distance parallel to the axial direction of the region 33a where the end of the insulating container 10 and the electric field relaxation shield 19-1 overlap, and is smaller than the axial distance between the rim portion 19-1a and the bottom portion 19b-3 of the electric field relaxation shield 19-1. The difference in distance is L1. Furthermore, the vacuum valve according to Example 3 can have the same configuration as in Figure 4, except that insulating member 35-2 is used instead of insulating member 34, and insulating member 36 is used instead of insulating member 35-2. Here, insulating member 35-2 is in contact with the sealing fitting 11, and the other insulating member is in contact with the sealing fitting 12, so the exposure of metal surfaces that could be the starting point of dielectric breakdown is less than in Examples 1 and 2.

[0033] By increasing the length of the rubber elastic body so that it contacts not only the insulating container but also the sealing fitting, the rubber elastic body adheres closely to the metal surface of the sealing fitting, reducing the exposed metal area that could be the starting point of dielectric breakdown, and thus increasing the dielectric breakdown voltage. Furthermore, a longer length of the rubber elastic body that contacts both the cylindrical insulator of the vacuum valve and the resin-coated electric field relaxation shield increases the distance of the interface where pressure is generated, which can also increase the dielectric breakdown voltage. Therefore, it is desirable that the length of the rubber elastic body be longer than the overlapping distance between the cylindrical insulator of the vacuum valve and the resin-coated electric field relaxation shield, but shorter than the length to the inner bottom surface of the resin-coated electric field relaxation shield. Thus, by simply providing a rubber elastic insulating material in part of the open section, the discharge path can be sufficiently blocked. [Examples]

[0034] Example 4 shows yet another example of a vacuum valve using a rubber elastic material as an insulating member. Figure 5 shows a partially enlarged view of the fixed electrode side of a fourth example of a vacuum valve according to the embodiment. As shown in Figure 5, the insulating member 35-3 made of a rubber elastic material used in Example 5 has a bowl shape and is provided in a region 33c that covers at least a part of the sealing fitting, from the part where the end of the insulating container 10 and the electric field mitigation shield 19-1 overlap to the part where the outside of the sealing fitting 11 and the electric field mitigation shield 19-1 overlap. Except for this, it can have the same configuration as the insulating member 34 in Figure 2. Furthermore, the vacuum valve according to Example 4 can have the same configuration as in Figure 1, except that insulating member 35-3 is used instead of insulating member 34, and insulating member 36 is used instead of insulating member 35-3.

[0035] The shape of this rubber elastic body is bowl-shaped, and one possible placement process is to attach a cylindrical rubber elastic body to a vacuum valve and then cover it with an electric field mitigation shield. If the rubber elastic body is cylindrical, when the fixed-side electric field mitigation shield is placed over it from the fixed electrode side toward the movable electrode, the rubber elastic body may also shift position toward the movable electrode. If the position shifts, the rubber elastic body may not be compressed to the specified amount, or the length of the compressed portion of the rubber elastic body may be shortened. In that case, the expected dielectric breakdown voltage may not be achieved. To prevent the position shift, methods such as using a jig to prevent the rubber elastic body from shifting when the electric field mitigation shield is placed over it, or fixing the rubber elastic body with adhesive, can be considered. However, this increases the number of steps and leads to increased costs. In contrast, in Example 4, by making the rubber elastic body the same bowl shape as the electric field mitigation shield, the rubber elastic body catches on the sealing fitting, and even when the electric field mitigation shield is placed over it, the rubber elastic body is less likely to shift position relative to the vacuum valve's energizing axis. Furthermore, during assembly, it is simply a matter of stacking the rubber elastic body and the electric field relaxation shield on top of the vacuum valve, eliminating the need to fix the position of the rubber elastic body with jigs or adhesives.

[0036] Furthermore, the insulating member 35-3 is in contact with the sealing fitting 11, and the other insulating member is in contact with the sealing fitting 12, resulting in less exposure of the metal surface that could be the starting point for dielectric breakdown compared to Examples 1 to 3. By increasing the length of the rubber elastic material so that it contacts not only the insulating container but also the sealing metal, the rubber elastic material adheres closely to the metal surface of the sealing metal, reducing the amount of exposed metal that could be the starting point of dielectric breakdown, and thus increasing the dielectric breakdown voltage. Furthermore, if the length of the rubber elastic material that contacts both the cylindrical insulator of the vacuum valve and the resin-coated electric field relaxation shield is longer, the distance of the interface where pressure is generated increases, which can also increase the dielectric breakdown voltage. [Examples]

[0037] Example 5 shows yet another example of a vacuum valve using a rubber elastic material as an insulating member. Figure 6 shows a partially enlarged view of the fixed electrode side of a fifth example of a vacuum valve according to the embodiment. The vacuum valve according to Example 5 has a structure that prevents displacement of the rubber elastic body. As shown in Figure 6, in Example 5, the outer diameter of the central part 10c is made thicker than the outer diameter of the region overlapping with the electric field mitigation shield 19-1 at the end of the insulating container 10. The central part 10c forms a step between the end of the insulating container 10 and the region 33a overlapping with the electric field mitigation shield 19-1. When the fixed electric field mitigation shield 19-1 is placed over the insulating member 34-4 from the fixed electrode side toward the movable electrode during manufacturing, this step catches and supports the insulating member 34-4, thereby preventing the rubber elastic body from shifting toward the movable electrode. For example, the insulating member 35-4 made of rubber elastic material can have the same configuration as the insulating member 35-2 in Figure 4 used in Example 3.

[0038] Furthermore, the vacuum valve according to Example 3 can have the same configuration as in Figure 1, except that the outer diameter of the central portion 10c is made larger than the outer diameter of the region overlapping with the electric field relaxation shields 19-1 and 20-1 at the ends of the insulating container 10, insulating member 35-4 is used instead of insulating member 34, and insulating member 36 is used instead of insulating member 35-4. In this case, insulating member 35-4 is in contact with the sealing fitting 11, and the other insulating member is in contact with the sealing fitting 12, resulting in less exposure of the metal surface that could be the starting point for dielectric breakdown compared to Examples 1 to 3. By increasing the length of the rubber elastic material so that it contacts not only the insulating container but also the sealing metal, the rubber elastic material adheres closely to the metal surface of the sealing metal, reducing the amount of exposed metal that could be the starting point for dielectric breakdown, and thus increasing the dielectric breakdown voltage. [Examples]

[0039] Example 6 shows yet another example of a vacuum valve using a rubber elastic material as an insulating member. Figure 7 shows a partially enlarged view of the fixed electrode side of the sixth example of the vacuum valve according to the embodiment. The vacuum valve according to Example 6 has a structure that prevents displacement of the rubber elastic body. As shown in Figure 7, in Example 6, a recess 10d is formed in the region of the insulating container 10 that overlaps with the electric field mitigation shield 19-1 at the end of the insulating container 10. The lower end of the recess 10d can be positioned, for example, at the same position as the rim portion 19-1a of the electric field mitigation shield 19-1. When the fixed electric field mitigation shield 19-1 is placed over the insulating container 10 from the fixed electrode side toward the movable electrode, the insulating member 35-5 fits into and is supported in this recess 10d, thereby preventing the rubber elastic body from shifting in the direction of the movable electrode. The axial length of the insulating member 35-5 made of rubber elastic body is shorter than the axial length of the insulating container 10 in the region of the insulating container 10 that overlaps with the electric field mitigation shield 19-1 at the end of the insulating container 10, and 2 mm shorter than the axial length of the recess 10d, so that when the thickness of the rubber elastic body is 6 mm, it is compressed by 2 mm.

[0040] Furthermore, the vacuum valve according to Example 6 can have the same configuration as in Figure 1, except that a groove is formed at the end of the insulating container 10, insulating member 35-5 is used instead of insulating member 34, and insulating member 36 is used instead of insulating member 35-5. Thus, by simply providing a rubber elastic insulating material in part of the open section, the discharge path can be sufficiently blocked. [Examples]

[0041] Example 7 shows yet another example of a vacuum valve using a rubber elastic material as an insulating member. Figure 8 shows a partially enlarged view of the fixed electrode side of the seventh example of the vacuum valve according to the embodiment. The vacuum valve according to Example 7 has a structure that prevents displacement of the rubber elastic body. As shown in Figure 8, in Example 7, the rim portion 19-1a of the coating resin layer 19a of the electric field mitigation shield 19-1 is deformed inward to provide a protruding portion 19-1b. As a result, the coating resin layer 19a provided on the inner surface of the electric field mitigation shield 19-1 forms a step that supports the insulating member 35-6 in the region 33a where the end of the insulating container 10, the sealing fitting 11, and the joint portion 31 overlap with the electric field mitigation shield 19-1. When the fixed electric field mitigation shield 19-1 is placed over the fixed electrode from the fixed electrode side toward the movable electrode, the insulating member 35-6 is caught and supported by this step, thereby preventing the rubber elastic body from shifting in the direction of the movable electrode. The insulating member 35-6 made of rubber elastic material can have a configuration similar to, for example, the insulating member 35-2 used in Example 3.

[0042] Furthermore, the vacuum valve according to Example 7 has a step created by a protruding portion of the coating resin layer 19a in the region where the end of the insulating container, the sealing fitting, and the joint overlap with the electric field mitigation shield, and can have the same configuration as in Figure 1, except that insulating member 35-6 is used instead of insulating member 34, and insulating member 36 is used instead of insulating member 35-6. Thus, by simply providing a rubber elastic insulating material in part of the open section, the discharge path can be sufficiently blocked. [Examples]

[0043] Example 8 shows yet another example of a vacuum valve using a rubber elastic material as an insulating member. Figure 9 shows a partially enlarged view of the fixed electrode side of the eighth example of the vacuum valve according to the embodiment. The vacuum valve according to Example 8 has a structure that prevents displacement of the rubber elastic body. As shown in Figure 9, in Example 8, the coating resin layer 19a provided on the inner surface 19b-2 of the electric field mitigation shield 19-1 has a recess 19-1c that supports the insulating member 35-7 in the region 33a where the end of the insulating container 10, the sealing fitting 11, and the joint 31 overlap with the electric field mitigation shield 19-1. When the fixed electric field mitigation shield 19-1 is placed over the fixed electrode from the fixed electrode side toward the movable electrode, the insulating member 35-7 fits into and is supported in this recess 19-1c, thereby preventing the rubber elastic body from shifting in the direction of the movable electrode. The insulating member 35-7, which is made of rubber elastic material, can have a configuration similar to, for example, the insulating member 35-2 used in Example 3.

[0044] Furthermore, the vacuum valve according to Example 8 has a recess in the coating resin layer 19a in the region where the end of the insulating container, the sealing fitting, and the joint overlap with the electric field mitigation shield, and can have the same configuration as in Figure 1, except that insulating member 35-7 is used instead of insulating member 34, and insulating member 36 is used instead of insulating member 35-7. Thus, by simply providing a rubber elastic insulating material in part of the open section, the discharge path can be sufficiently blocked. [Examples]

[0045] Example 9 shows yet another example of a vacuum valve using a rubber elastic material as an insulating member. Figure 10 shows a partially enlarged view of the fixed electrode side of the ninth example of the vacuum valve according to the embodiment. Example 9: The vacuum valve has a structure in which the pressure generated against the rubber elastic sealing fitting is reduced compared to the pressure generated against the insulating container. As shown in Figure 10, the insulating member includes a first insulating member having a first rubber hardness and a second insulating member having a second rubber hardness different from the first rubber hardness. For example, the rubber elastic body 35-8 has a rubber elastic body 35-8b in the region 33b that contacts the sealing fitting and a rubber elastic body 35-8a in the region 33a that contacts the insulating container. The thickness of the rubber elastic body 35-8a can be adjusted to be harder than the rubber elastic body 35-8b, or to have a greater compressive amount. When adjusting the hardness, for example, the rubber elastic body 35-8a can have a hardness of 50 and the rubber elastic body 35-8b can have a hardness of 30, and the compressive amount for both can be 2 mm. When adjusting the compressive amount, for example, the thickness of the rubber elastic body 35-8a can be adjusted so that the compressive amount is 3 mm and the rubber elastic body 35-b has a compressive amount of 1 mm, and a rubber hardness of 30 can be used for both. It is also possible to change both the hardness and the compressive amount. This reduces the pressure generated on the sealing device compared to the pressure generated on the insulating container.

[0046] The more closely the rubber elastic material adheres to the sealing fitting and the less metal is exposed, the higher the dielectric breakdown voltage. Also, the greater the compressive force generated when the rubber elastic material is compressed, the higher the pressure generated at the interface between the rubber elastic material and the insulating container, field mitigation shield, and sealing fitting, and thus the higher the dielectric breakdown voltage. However, due to its shape and the fact that the sealing fitting is made of metal, it is more easily deformed than ceramic, which is commonly used as an insulating container. If the same pressure as that generated at the interface between the insulating container and the rubber elastic material is generated at the sealing fitting, there is a risk of deformation of the sealing fitting or delamination of the adhesive between the sealing fitting and the insulating container. In contrast, in Example 9, the compressive load generated in the rubber elastic material at the sealing fitting 11 and the joint 31 between the sealing fitting 11 and the insulating container 10 can be made lower than the compressive load generated in the rubber elastic material at the location in contact with the insulating container 10. [Examples]

[0047] Example 10 shows yet another example of a vacuum valve using a rubber elastic material as an insulating member. Figure 11 shows a partially enlarged view of the fixed electrode side of the 10th example of the vacuum valve according to the embodiment. As shown in Figure 11, the insulating member includes, for example, a rubber elastic body 35-9 which includes a first insulating member having a first rubber hardness and a second insulating member having a second rubber hardness different from the first rubber hardness. The rubber elastic body 35-9b has a region 33b that contacts the sealing fitting and a rubber elastic body 35-9a has a region 33a that contacts the insulating container. The thickness of the rubber elastic body 35-9a is adjusted to be harder than the rubber elastic body 35-9b or to have a greater compressive capacity. The adjustment of hardness and compressive capacity can be done in the same way as in Example 9. As a result, the pressure generated against the sealing fitting is reduced compared to the pressure generated against the insulating container.

[0048] The vacuum valve according to Example 10 has a structure in which the pressure generated against the rubber elastic sealing fitting is reduced compared to the pressure generated against the insulating container. Furthermore, in Figure 11, the rubber elastic body 35-9b has a shape that extends more towards the center of the sealing fitting 11 than the rubber elastic body 35-8b in Figure 10. Therefore, the entire insulating member 35-9 can have a bowl shape, similar to the insulating member 35-3 in Figure 5. One possible process for arranging a bowl-shaped rubber elastic body is to attach a cylindrical rubber elastic body to a vacuum valve and then place an electric field mitigation shield over it. However, if the rubber elastic body is cylindrical, when the fixed-side electric field mitigation shield is placed over it from the fixed electrode side towards the movable electrode, the rubber elastic body may also shift in position towards the movable electrode. In contrast, in Example 10, by making the rubber elastic body the same bowl shape as the electric field mitigation shield, the rubber elastic body catches on the sealing fitting, and even when the electric field mitigation shield is placed over it, the rubber elastic body is less likely to shift in position relative to the vacuum valve's energizing axis. Furthermore, in assembly, it is only necessary to stack the rubber elastic body and then the electric field mitigation shield on top of the vacuum valve, eliminating the need to fix the position of the rubber elastic body with jigs or adhesives.

[0049] Furthermore, the insulating member 35-9 is in contact with the sealing fitting 11, and the other insulating member is in contact with the sealing fitting 12, resulting in less exposure of the metal surface that could be the starting point for dielectric breakdown compared to Example 9. By increasing the length of the rubber elastic material so that it contacts not only the insulating container but also the sealing metal, the rubber elastic material adheres closely to the metal surface of the sealing metal, reducing the amount of exposed metal that could be the starting point for dielectric breakdown, and thus increasing the dielectric breakdown voltage. Furthermore, if the length of the rubber elastic material that contacts both the cylindrical insulator of the vacuum valve and the resin-coated electric field relaxation shield is longer, the distance of the interface where pressure is generated increases, which can also increase the dielectric breakdown voltage.

[0050] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0051] 10...Insulating container, 32...Joint, 100...Vacuum container, 14, 15...Electrodes, 19-1, 20-1...Field mitigation shield, 19a...Insulating coating layer, 37...Open section, 34...Insulating member, 19-1b...Protrusion, 105...Vacuum valve

Claims

1. An insulating container having openings at both ends, and a vacuum container having a sealing fitting having an opening, each joined to the openings via a joint, A pair of electrodes are detachably arranged facing each other within the vacuum container, The end of the insulating container, the sealing fitting, and the electric field mitigation shield provided to cover the joint, An insulating coating layer provided on at least a portion of the surface of the electric field relaxation shield, An open portion including a gap is provided in at least a part of the region between the end of the insulating container, the sealing fitting, the joint, and the electric field mitigation shield, A vacuum valve characterized by including an insulating member partially provided in the opening.

2. The vacuum valve according to claim 1, wherein the void in the open portion is in a dry gas atmosphere.

3. The vacuum valve according to claim 1, wherein the opening portion has a metal exposed portion on its surface.

4. The vacuum valve according to claim 1, wherein the insulating member is a rubber elastic body.

5. The vacuum valve according to claim 1, wherein the insulating member is an adhesive.

6. The vacuum valve according to claim 1, wherein the insulating member is a protruding portion that extends from a part of the insulating coating layer.

7. The vacuum valve according to claim 1, wherein the thickness of the insulating member perpendicular to the axial direction of the insulating container is greater than the distance of the gap perpendicular to the axial direction of the insulating container.

8. The vacuum valve according to claim 1, wherein the length of the insulating member parallel to the axial direction of the insulating container is equal to or less than the axial distance of the region in which the end of the insulating container and the electric field relaxation shield overlap.

9. The vacuum valve according to claim 1, wherein the insulating member has an axial length of the insulating container that is greater than the axial distance of the region where the end of the insulating container and the electric field relaxation shield overlap, and is less than the axial distance between the rim and the bottom of the electric field relaxation shield. → Example 2

10. The vacuum valve according to claim 1, wherein the insulating member is provided so as to cover at least a portion of the sealing fitting.

11. The vacuum valve according to claim 1, wherein the end of the insulating container has a step that supports the insulating member within the region overlapping with the electric field relaxation shield.

12. The vacuum valve according to claim 1, wherein the end of the insulating container has a recess for supporting the insulating member in a region that overlaps with the electric field relaxation shield.

13. The vacuum valve according to claim 1, wherein the coating resin layer provided on the inner surface of the electric field mitigation shield has a step that supports the insulating member in the region where the end of the insulating container, the sealing fitting, and the joint overlap with the electric field mitigation shield.

14. The vacuum valve according to claim 1, wherein the coating resin layer provided on the inner surface of the electric field mitigation shield has a recess for supporting the insulating member in the region where the end of the insulating container, the sealing fitting, and the joint overlap with the electric field mitigation shield.

15. The vacuum valve according to claim 1, wherein the insulating member comprises a first insulating member having a first rubber hardness and a second insulating member having a second rubber hardness different from the first rubber hardness.

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