Vacuum Circuit Breaker

Abstract

A vacuum circuit breaker (100) comprising: a vacuum valve (1) equipped with a bellows (2); a tank (5) for housing the vacuum valve (1); a flange attached to an opening of the tank (5) to form a space for sealing high-pressure insulating gas; and an operating mechanism (6) installed outside the tank (5) for opening and closing the vacuum valve (1). The flange is composed of a first flange (3A) on the atmospheric side outside the tank (5) and a second flange (3B) on the insulating gas side inside the tank (5). An intermediate chamber (4) is formed between the first flange (3A) and the second flange (3B). The vacuum valve (1) is fixed to the second flange (3B) via an insulating tube (7). The intermediate chamber (4), the inside of the insulating tube (7), and the inside of the bellows (2) of the vacuum valve (1) are connected to each other, and a pressure intermediate between the gas pressure of the insulating gas and atmospheric pressure is maintained.

Description

[Technical field]

[0001] The present disclosure relates to a vacuum interrupter. [Background technology]

[0002] In recent years, due to environmental considerations, insulating gases are being changed from SF6 (sulfur hexafluoride) gas to gases with lower environmental impact, for example, gases with lower global warming potential (GWP). When changing the gas sealed inside the tank to one with lower environmental impact, the gas pressure must be increased to obtain the same voltage resistance performance as SF6 gas. In this case, there is a risk that the bellows in the moving part of the vacuum valve will deform or break due to the pressure difference between the high gas pressure inside the tank and the vacuum inside the vacuum valve.

[0003] To solve this problem, a gas-insulated switchgear has been disclosed that has a double pressure structure using two bellows to reduce the burden on the bellows. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-236455 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the device of the patent document, the space formed by the two bellows is sealed off, making it difficult to fill and replenish the gas. In addition, high gas pressure causes significant deformation of the flange to which the vacuum bellows and its operating mechanism are fixed, which may adversely affect the alignment (axis alignment) of the entire vacuum circuit breaker.

[0006] The present disclosure discloses technology for solving the problems described above, and provides a vacuum circuit breaker having a structure that suppresses deformation of the flange and bellows due to pressure sharing and enables gas to be sealed and replenished. [Means for solving the problem]

[0007] The vacuum circuit breaker of the present disclosure is a vacuum circuit breaker comprising: a vacuum valve equipped with a bellows for maintaining a vacuum; a tank for housing the vacuum valve; a flange attached to an opening of the tank to form a space for sealing a high-pressure insulating gas; and an operating mechanism installed outside the tank for operating the opening and closing of the vacuum valve, wherein the flange is composed of a first flange on the atmospheric side outside the tank and a second flange on the insulating gas side inside the tank, and an intermediate chamber is formed between the first flange and the second flange, the vacuum valve is fixed to the second flange via an insulating tube, the intermediate chamber is connected to the inside of the insulating tube and the inside of the bellows of the vacuum valve, and a pressure intermediate between the gas pressure of the insulating gas and atmospheric pressure is maintained. A gas pipe for supplying gas to the intermediate chamber is provided outside the tank. It is something. The vacuum circuit breaker of the present disclosure comprises a vacuum valve equipped with a bellows for maintaining a vacuum, a tank for housing the vacuum valve, a flange attached to an opening of the tank to form a space for sealing in high pressure insulating gas, and an operating mechanism installed outside the tank for opening and closing the vacuum valve, wherein the flange is composed of a first flange on the atmospheric side outside the tank and a second flange on the insulating gas side inside the tank, an intermediate chamber is formed between the first flange and the second flange, the vacuum valve is fixed to the second flange via an insulating tube, the intermediate chamber is connected to the inside of the insulating tube and the inside of the bellows of the vacuum valve, and a pressure intermediate between the gas pressure of the insulating gas and atmospheric pressure is maintained, The intermediate chamber is provided on the outside of the tank. The vacuum circuit breaker of the present disclosure comprises a vacuum valve equipped with a bellows for maintaining a vacuum, a tank for housing the vacuum valve, a flange attached to an opening of the tank to form a space for sealing in high pressure insulating gas, and an operating mechanism installed outside the tank for opening and closing the vacuum valve, wherein the flange is composed of a first flange on the atmospheric side outside the tank and a second flange on the insulating gas side inside the tank, an intermediate chamber is formed between the first flange and the second flange, the vacuum valve is fixed to the second flange via an insulating tube, the intermediate chamber is connected to the inside of the insulating tube and the inside of the bellows of the vacuum valve, and a pressure intermediate between the gas pressure of the insulating gas and atmospheric pressure is maintained, This is a three-phase type having three vacuum valves, and a three-phase branching section that branches the operating mechanism into three phases is provided in the intermediate chamber. Effect of the Invention

[0008] According to the vacuum circuit breaker of the present disclosure, a vacuum circuit breaker can be obtained that realizes a structure that suppresses deformation of the flange and bellows due to pressure sharing and enables gas to be sealed and replenished. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a vacuum circuit breaker according to a first embodiment. [Diagram 2] 2 is a detailed diagram of an airtight drive unit of the vacuum circuit breaker according to the first embodiment. FIG. [Diagram 3] FIG. 1 is a side view of a vacuum circuit breaker according to a first embodiment. [Figure 4]FIG. 11 is a cross-sectional view of a vacuum circuit breaker according to a second embodiment. [Diagram 5] FIG. 11 is a cross-sectional view of a vacuum circuit breaker according to a third embodiment. [Figure 6] FIG. 11 is a detailed diagram of an airtight drive unit of the vacuum circuit breaker according to the third embodiment. [Figure 7] FIG. 11 is a cross-sectional view of a vacuum circuit breaker according to a fourth embodiment. [Figure 8] FIG. 11 is a detailed diagram of an airtight drive unit of a vacuum circuit breaker according to a fourth embodiment. [Figure 9] FIG. 11 is a cross-sectional view of a vacuum circuit breaker according to a fifth embodiment. [Figure 10] FIG. 13 is a detailed diagram of an airtight drive unit of the vacuum circuit breaker according to the fifth embodiment. [Figure 11] FIG. 13 is a cross-sectional view of a vacuum circuit breaker according to a sixth embodiment. [Figure 12] FIG. 13 is a cross-sectional view of a vacuum circuit breaker according to a seventh embodiment. [Figure 13] FIG. 13 is a detailed diagram of an airtight drive unit of a vacuum circuit breaker according to a seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Embodiment 1 The first embodiment relates to a vacuum circuit breaker comprising a vacuum valve, a tank for housing the vacuum valve, a flange for attaching to the opening of the tank to form a space for sealing high-pressure insulating gas, and an operating mechanism for opening and closing the vacuum valve, the flange consisting of a first flange on the atmospheric side outside the tank and a second flange on the insulating gas side inside the tank, an intermediate chamber being formed between the first flange and the second flange, the vacuum valve being fixed to the second flange via an insulating tube, the intermediate chamber being connected to the inside of the insulating tube and the inside of the bellows of the vacuum valve, and the pressure being intermediate between the gas pressure of the insulating gas and atmospheric pressure. In this disclosure, the vacuum circuit breaker, which is a main part of the gas-insulated switchgear, will be described in order. In the first embodiment, a vacuum circuit breaker compatible with a three-phase AC power supply will be described, and in the sixth embodiment described below, a vacuum circuit breaker compatible with a single-phase AC power supply will be described.

[0011] A vacuum circuit breaker according to embodiment 1 will be described below with reference to FIG. 1, a cross-sectional view of the vacuum circuit breaker, FIG. 2, a detailed view of an airtight drive unit of the vacuum circuit breaker, and FIG. 3, a side view of the vacuum circuit breaker. In each drawing, the same or corresponding parts are indicated by the same reference numerals, and duplicated explanations will be omitted. 1 is defined as the Z direction, the left-right direction as the X direction, and the front-rear direction as the Y direction, and the directions of the arrows are defined as the positive sides.

[0012] First, the configuration and functions of a vacuum circuit breaker 100 according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG. 2 shows details of the airtight drive unit, which is a main part of the vacuum circuit breaker 100. Here, the airtight drive unit refers to the space inside the tank 5 in which the vacuum valve 1 is installed and in which insulating gas is sealed. 3 is a side view of the vacuum circuit breaker 100 as viewed from the right side of FIG. 1, that is, as viewed from the positive side to the negative side in the X direction.

[0013] The vacuum circuit breaker 100 comprises, as its main components, a vacuum valve 1, a tank 5 in which the vacuum valve 1 is installed and an insulating gas is sealed inside, a first flange 3A which is installed at the upper opening of the tank 5 to fix the vacuum valve 1 and seal in the insulating gas, and an operating mechanism 6 which opens and closes the vacuum valve 1.

[0014] In order to enable multiple vacuum circuit breakers 100 to be arranged side by side in a row, the tank 5 contains the vacuum valve 1 as well as a movable connecting conductor 8, a movable bus conductor 9, a fixed bus conductor 10, and a fixed connecting conductor 11 for connecting to other panels. Since the first embodiment is a three-phase vacuum circuit breaker, three vacuum valves 1, a movable side connecting conductor 8, a movable side busbar conductor 9, a fixed side busbar conductor 10, and a fixed side connecting conductor 11 are stored in a tank 5. In Fig. 3, the three vacuum valves 1, the movable side connecting conductor 8, and the movable side busbar conductor 9 can be seen from the front through the opening for the row panel. In this specification, the side where the movable contact of the vacuum valve 1 is located (the positive side in the Z direction in Figure 1) is referred to as the movable side, and the side where the fixed contact of the vacuum valve 1 is located (the negative side in the Z direction in Figure 1) is referred to as the fixed moving side.

[0015] In addition, in order to shorten the insulation distance, a first flange 3A is provided at the upper opening of the tank 5, the tank 5 is sealed, and a gas with excellent insulation performance (dry air, etc.) is enclosed therein. In order to insulate the three-phase vacuum valve 1 from the grounded tank 5, the movable side (positive side in the Z direction in Figure 1) is fixed to the tank 5 via an insulating tube 7, and the fixed side (negative side in the Z direction in Figure 1) is fixed to the tank 5 via a supporting insulator 12.

[0016] 1, gas piping 16 for supplying low-pressure gas to intermediate chamber 4, which will be described later, is installed in first flange 3A at the upper opening of tank 5. This low-pressure gas has a pressure between the pressure of the high-pressure insulating gas and the vacuum of vacuum valve 1, and it is desirable to use a gas with excellent insulating performance. Moreover, the operating mechanism 6 includes a three-phase branching section 6a for opening and closing the three vacuum valves 1.

[0017] FIG. 2 shows details of the airtight drive unit that is a feature of the vacuum circuit breaker 100. In order to separate a high-pressure space filled with a gas with excellent insulating properties from a low-pressure space, a double structure is formed with first flange 3A and second flange 3B to form low-pressure intermediate chamber 4, thus separating the gas compartments. When first flange 3A and second flange 3B are collectively described, they are referred to as flange 3.

[0018] In Fig. 2, the high pressure space (space H) is shown as a solid line with widely spaced diagonal lines extending from the upper right to the lower left, the low pressure space (space L) is shown as a solid line with diagonal lines extending from the upper right to the lower left, and the vacuum space (space V) is shown as a solid line with diagonal lines extending from the upper left to the lower right. Note that the pressure outside the tank 5 is atmospheric.

[0019] Airtightness is maintained at the boundary surface of the gas compartment by using a fixed seal or a sliding seal. In this specification, a sliding seal is defined as a structure in which a seal member comes into contact with a sliding portion and the contact portion changes, and a fixed seal is defined as a structure in which the contact portion of the seal member does not change, such as a bolt fastening portion. A sliding seal 14 is used at the contact portion between the operating mechanism 6 of the vacuum circuit breaker 100 and the first flange 3A to ensure that airtightness is not lost during opening and closing operations. As an example of a fixed seal, a fixed seal is used at the contact portion between the gas pipe 16 and the first flange 3A to maintain airtightness.

[0020] Both the fixed seal and the sliding seal use O-rings as sealing materials. The fixed seal is not a separate part like the sliding seal, but is constructed by, for example, carving a groove in the first flange 3A and inserting a seal member into this groove, and therefore is not shown in the drawings.

[0021] In addition, in FIG. 2, the insulating cylinder 7 is composed of an insulator 7a, a filler metal 7b, and a filler metal 7c. The filler metal 7b is a member for fixing the second flange 3B and the insulating cylinder 7, and a tap for fixing is cut on the filler metal 7b side, and an O-ring for sealing is installed. The filler metal 7c is a member for fixing the movable side connecting conductor 8 and the insulating tube 7, and a tap for fixing is cut on the filler metal 7c side, and an O-ring for sealing is installed.

[0022] As can be seen in FIG. 2, a low-pressure space (space L) is formed by the intermediate chamber 4, the inside of the insulating cylinder 7, the inside of the movable side connecting conductor 8, and the inside of the bellows 2. Therefore, the inside of the bellows 2 communicates with the intermediate chamber 4 and is under low pressure, and the outside of the bellows 2 is a vacuum.

[0023] Now, FIG. 3 will be described. Since embodiment 1 is a vacuum circuit breaker 100 compatible with a three-phase AC power source, three vacuum valves 1, three movable side connecting conductors 8, three movable side bus conductors 9, three fixed side bus conductors 10, and three fixed side connecting conductors 11 are stored inside the tank 5. 3 is a right side view of FIG. 1, the fixed bus conductor 10 and the fixed connecting conductor 11 are hidden and cannot be seen through the opening for the row panels on the front side of the tank 5.

[0024] Next, the effect of providing a low-pressure space (space L) in the airtight drive section, which is a feature of the vacuum circuit breaker 100, will be described. The first flange 3A and the second flange 3B form a double structure to provide a low-pressure intermediate chamber 4. This intermediate chamber 4 is connected to the inside of the insulating tube 7, the inside of the movable-side connecting conductor 8, and the inside of the bellows 2 to form a low-pressure space (space L). If the low-pressure space L is not provided, the first flange 3A is subjected to the pressure difference between the high pressure of the insulating gas and the atmospheric pressure, and the bellows 2 is subjected to the pressure difference between the high pressure of the insulating gas and the vacuum of the vacuum valve 1. By providing this low-pressure space L, it is possible to reduce the pressure difference between the high pressure of the insulating gas applied to the first flange 3A and the atmospheric pressure, and also to reduce the pressure difference between the high pressure of the insulating gas applied to the bellows 2 and the vacuum of the vacuum valve 1.

[0025] Furthermore, if the low-pressure space L is not provided, the bellows 2 will be affected by the high-pressure insulating gas. However, by providing the low-pressure space L, the inside of the bellows 2 will be subjected to the low pressure of the space L, rather than the high pressure of the insulating gas. For this reason, it becomes possible to use parts for the bellows 2 that are difficult to use under high gas pressure, expanding the range of parts selection. Furthermore, if the low-pressure space L is not provided, the first flange 3A will be affected by the high-pressure insulating gas. However, by providing the low-pressure space L, the inside of the first flange 3A will be subjected to the low pressure of the intermediate chamber 4, rather than the high pressure of the insulating gas. As a result, the first flange 3A is prevented from deforming as in flanges of conventional configurations, making it easier to align (align the axis) the entire vacuum circuit breaker. Furthermore, the differential pressure acting on the first flange 3A is reduced, and the strength of the first flange 3A can be reduced, thereby achieving cost reduction and weight reduction.

[0026] Furthermore, in the vacuum circuit breaker 100 of the first embodiment, the intermediate chamber 4 is common to each of the three phases, and communicates with the inside of the insulating cylinder 7, the movable side connecting conductor 8, and the bellows 2 of each phase to form the low-pressure space L. Therefore, when low-pressure gas is supplied to the low-pressure space L, it is not necessary to branch out to each phase, and gas can be charged and replenished using a single gas pipe 16.

[0027] As described above, the vacuum circuit breaker of the first embodiment provides a low-pressure space between the high pressure of the insulating gas and the vacuum, thereby realizing a structure that suppresses deformation of the flange and bellows due to pressure sharing and enables gas charging and replenishment. Furthermore, gas can be charged and replenished into this three-phase low-pressure space by a single gas piping.

[0028] Embodiment 2 In the second embodiment, the movable side of the vacuum valve is installed at the bottom of the tank.

[0029] A vacuum circuit breaker according to a second embodiment will be described with reference to FIG. 4, which is a cross-sectional view of the vacuum circuit breaker, focusing on the differences from the first embodiment. In the configuration diagram of the second embodiment, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals. In order to distinguish from the first embodiment, the second embodiment is referred to as a vacuum circuit breaker 200.

[0030] As shown in Fig. 4, in a vacuum circuit breaker 200 of the second embodiment, a first flange 3A and a second flange 3B to which the movable side of the vacuum valve 1 is fixed via an insulating cylinder 7 are fixed to the bottom surface of a tank 5. The fixed side of the vacuum valve 1 (the positive side in the Z direction in Fig. 4) is fixed to the top surface of the tank 5 via a supporting insulator 12. An operating mechanism 6 for opening and closing the vacuum valve 1 and a three-phase branching section 6a are also installed on the lower side of the tank 5. 1. Moreover, the installation direction (Z direction) of the bellows 2, the movable connecting conductor 8, and the fixed connecting conductor 11 is opposite to that in FIG. In order to make the drawing easier to understand, the movable bus conductor 9 and the fixed bus conductor 10 are omitted in Fig. 4. The other configurations are the same as those in the first embodiment, and therefore the description thereof will be omitted.

[0031] Next, features of the vacuum circuit breaker 200 according to the second embodiment will be described. In the second embodiment, the vacuum valve 1 is attached to the bottom of the tank 5, and the intermediate chamber 4 is located on the bottom side of the tank 5 (negative side in the Z direction), but similarly to the first embodiment, the intermediate chamber 4 is common to each of the three phases, and communicates with the inside of the insulating tube 7, movable side connecting conductor 8, and bellows 2 of each phase to form the low-pressure space L. Therefore, when supplying low-pressure gas to the low-pressure space L, it is not necessary to branch to each phase, and gas can be charged and replenished using a single gas pipe 16. Furthermore, as in embodiment 1, by forming an intermediate chamber 4 between the first flange 3A and the second flange 3B, the pressure difference is shared, the deformation that occurred in the flanges of the conventional configuration is suppressed, and alignment (axis alignment) of the entire vacuum circuit breaker is facilitated. Furthermore, in embodiment 2, since the movable side of the vacuum valve 1 is located on the bottom side of the tank 5, when interrupting an abnormal current, gravity acts on the drive rod portion moving downward in the Z direction, thereby increasing the opening speed of the vacuum circuit breaker.

[0032] As described above, the vacuum circuit breaker of the second embodiment provides a low-pressure space between the high pressure of the insulating gas and the vacuum, thereby realizing a structure that suppresses deformation of the flange and bellows due to pressure sharing and enables gas charging and replenishment. Furthermore, gas can be charged and replenished into this three-phase low-pressure space by a single gas pipe. Also, the opening speed of the vacuum circuit breaker is increased when interrupting an abnormal current.

[0033] Embodiment 3 In the third embodiment, a contact portion between the operating mechanism of the vacuum circuit breaker and the opening of the first flange is configured to maintain airtightness by a bellows.

[0034] A vacuum circuit breaker according to a third embodiment will be described with reference to FIG. 5, which is a cross-sectional view of the vacuum circuit breaker, and FIG. 6, which is a detailed view of an airtight drive unit of the vacuum circuit breaker, focusing on the differences from the first embodiment. In the configuration diagram of the third embodiment, the same or corresponding parts as those in the first embodiment are given the same reference numerals. In order to distinguish from the first embodiment, the third embodiment is referred to as a vacuum circuit breaker 300.

[0035] In the vacuum circuit breaker 300 of the third embodiment, the contact portion between the operating mechanism 6 and the opening of the first flange 3A is configured to maintain airtightness by the bellows 21. The bellows 21 has a bellows body 21a brazed to a bellows mounting flange 21b, which is fixed to the first flange 3A. A fixed seal is used at the boundary between the first flange 3A and the bellows mounting flange 21b to maintain airtightness. The other configuration is the same as in the first embodiment, so the description will be omitted.

[0036] Next, features of the vacuum circuit breaker 300 according to the third embodiment will be described. In the third embodiment, airtightness is maintained by connecting the contact portion between the operating mechanism 6 of the vacuum valve 1, which slides due to the opening and closing operation of the vacuum circuit breaker 300, and the opening of the first flange 3A with a bellows 21. Because the bellows can expand and contract, airtightness can be maintained similarly to the sliding seal used in the first embodiment, even when opening and closing operations occur. Furthermore, when a sliding seal is used, a fixed seal comes into contact with the part that slides due to the opening and closing operation, and there is a risk of the fixed seal being worn. However, when the bellows 21 is used, a fixed seal can be used at the boundary between the first flange 3A and the bellows mounting flange 21b, eliminating the risk of the fixed seal being worn due to sliding.

[0037] As described above, the vacuum circuit breaker of the third embodiment provides a low-pressure space between the high pressure of the insulating gas and the vacuum, thereby realizing a structure that suppresses deformation of the flange and bellows due to pressure sharing and enables gas charging and replenishment. Furthermore, gas can be charged and replenished into this three-phase low-pressure space by a single gas pipe. In addition, it is possible to eliminate the risk of wear on the fixed seal at the contact portion between the operating mechanism of the vacuum valve and the opening of the first flange.

[0038] Embodiment 4 In the fourth embodiment, a three-phase branch portion of an operating mechanism of a vacuum circuit breaker is housed in an intermediate chamber formed by a first flange and a second flange.

[0039] A vacuum circuit breaker according to a fourth embodiment will be described with reference to FIG. 7 which is a cross-sectional view of the vacuum circuit breaker, and FIG. 8 which is a detailed view of the airtight drive unit of the vacuum circuit breaker, focusing on the differences from the first embodiment. In the configuration diagram of the fourth embodiment, the same or corresponding parts as those in the first embodiment are given the same reference numerals. In order to distinguish from the first embodiment, the fourth embodiment is described as a vacuum circuit breaker 400 and a three-phase branching section 6b.

[0040] As shown in Figures 7 and 8, in a vacuum circuit breaker 400 of embodiment 4, a three-phase branching portion 6b of an operating mechanism 6 is configured to be installed in an intermediate chamber 4 formed by a first flange 3A and a second flange 3B. The other configuration is the same as in the first embodiment, so the description will be omitted.

[0041] Next, features of the vacuum circuit breaker 400 according to the fourth embodiment will be described. In the fourth embodiment, the three-phase branching portion 6b of the operating mechanism 6 of the vacuum circuit breaker 400 is disposed in the intermediate chamber 4, so that the contact portion between the operating mechanism 6 and the first flange 3A can be kept airtight by a single sliding seal 14. Since the number of locations where gas sealing is performed is reduced, it is possible to reduce costs and improve leak resistance while ensuring airtightness.

[0042] As described above, the vacuum circuit breaker of the fourth embodiment provides a low-pressure space between the high pressure of the insulating gas and the vacuum, thereby realizing a structure that suppresses deformation of the flange and bellows due to pressure sharing and enables gas injection and replenishment. Furthermore, gas can be injected and replenished into this three-phase low-pressure space by a single gas pipe. In addition, costs can be reduced and leak resistance can be improved.

[0043] Embodiment 5. In the fifth embodiment, the second flange and the insulating cylinder are integrally molded to form an insulating flange.

[0044] A vacuum circuit breaker according to a fifth embodiment will be described with reference to FIG. 9, which is a cross-sectional view of the vacuum circuit breaker, and FIG. 10, which is a detailed view of the airtight drive unit of the vacuum circuit breaker, focusing on the differences from the first embodiment. In the configuration diagram of the fifth embodiment, parts that are the same as or equivalent to those of the first embodiment are given the same reference numerals. In order to distinguish from the first embodiment, the fifth embodiment is referred to as a vacuum circuit breaker 500.

[0045] In the fifth embodiment, the second flange 3B and the insulating cylinder 7 in the first embodiment are integrally molded as an insulator flange 22. The first flange 3A and the integrally molded insulator flange 22 form an intermediate chamber 4. 10, the insulator flange 22 is composed of an insulator 22a and a filler metal 22b. The filler metal 22b is a member for fixing the movable-side connecting conductor 8 to the insulator flange 22, and a tap for fixing is cut on the filler metal 22b side, and an O-ring for sealing is installed. The other configuration is the same as in the first embodiment, and therefore the description will be omitted.

[0046] Next, features of the vacuum circuit breaker 500 according to the fifth embodiment will be described. In the fifth embodiment, the function of the second flange 3B which forms the intermediate chamber 4 together with the first flange 3A and the function of the insulating cylinder 7 which ensures insulation between the movable side connecting conductor 8, which is the live part, and the tank 5 are integrated by being molded as an insulator flange 22. As a result, the number of parts can be reduced. By reducing the number of parts, the number of locations where gas sealing is required is also reduced (specifically, the filler metal 7b in FIG. 2 is no longer necessary), making it possible to improve leak performance while maintaining airtightness.

[0047] As described above, the vacuum circuit breaker of the fifth embodiment provides a low-pressure space between the high pressure of the insulating gas and the vacuum, thereby realizing a structure that suppresses deformation of the flange and bellows due to pressure sharing and enables gas injection and replenishment. Furthermore, gas can be injected and replenished into this three-phase low-pressure space by a single gas pipe. In addition, the number of parts can be reduced and leak resistance can be improved.

[0048] Embodiment 6 The sixth embodiment is a single-phase vacuum circuit breaker.

[0049] A vacuum circuit breaker according to a sixth embodiment will be described with reference to FIG. 11, which is a cross-sectional view of the vacuum circuit breaker, focusing on the differences from the first embodiment. In the configuration diagram of the fifth embodiment, parts that are the same as or equivalent to those of the first embodiment are given the same reference numerals. In order to distinguish from the first embodiment, the sixth embodiment is referred to as a vacuum circuit breaker 600.

[0050] The sixth embodiment is a single-phase vacuum circuit breaker in which one vacuum valve 1 is housed in a tank 5 . As in embodiment 1, a double structure is formed by the first flange 3A and the second flange 3B, providing an intermediate chamber 4, and this intermediate chamber 4 is connected to the inside of the insulating tube 7, the inside of the movable side connecting conductor 8, and the inside of the bellows 2 to form a low-pressure space (space L). Other than the configuration in which one vacuum valve 1 is housed in a tank 5, the configuration is the same as that of the first embodiment, so a description thereof and a detailed diagram of the airtight drive unit will be omitted.

[0051] Next, the features of the single-phase vacuum circuit breaker 600 according to the sixth embodiment will be described. By providing the low-pressure space L, it is possible to reduce the pressure difference between the high pressure of the insulating gas applied to the first flange 3A and the atmospheric pressure. Also, it is possible to reduce the pressure difference between the high pressure of the insulating gas applied to the bellows 2 and the vacuum of the vacuum valve 1. Furthermore, gas can be filled and replenished into the low pressure space L through gas piping 16.

[0052] As described above, the single-phase vacuum circuit breaker of embodiment 6 provides a low-pressure space that is intermediate between the high pressure of the insulating gas and the vacuum, thereby realizing a structure that suppresses deformation of the flange and bellows due to pressure sharing and enables gas to be sealed and replenished.

[0053] Embodiment 7 The seventh embodiment is configured such that an intermediate chamber is provided outside the tank.

[0054] The vacuum circuit breaker of the seventh embodiment will be described with reference to FIG. 12, which is a cross-sectional view of the vacuum circuit breaker, and FIG. 13, which is a detailed view of the airtight drive unit of the vacuum circuit breaker, focusing on the differences from the first embodiment. In the configuration diagram of the fifth embodiment, parts that are the same as or equivalent to those of the first embodiment are given the same reference numerals. In order to distinguish from the first embodiment, the seventh embodiment is referred to as a vacuum circuit breaker 700, a third flange 31A, and a fourth flange 31B.

[0055] 12, in the seventh embodiment, the first flange 3A in the first embodiment is fixed to the tank 5 by a flat flange plate as a fourth flange 31B. The vacuum valve 1 is fixed to the fourth flange 31B via an insulating cylinder 7. The second flange 3B in the first embodiment is fixed to the fourth flange 31B as a third flange 31A, thereby providing an intermediate chamber 4 outside the tank 5. The third flange 31A and the fourth flange 31B form a double structure to provide an intermediate chamber 4, which is connected to the inside of the insulating tube 7, the inside of the movable side connecting conductor 8, and the inside of the bellows 2 to form a low-pressure space (space L). The other configuration is the same as in the first embodiment, so the description will be omitted.

[0056] Next, features of the vacuum circuit breaker 700 according to the seventh embodiment will be described. In embodiment 7, an intermediate chamber 4 is formed outside the tank 5 by a fourth flange 31B fixed to the tank 5 and a third flange 31A fixed to this fourth flange 31B, thereby reducing the pressure difference between the high pressure of the insulating gas and the atmospheric pressure and the vacuum inside the vacuum valve 1. In addition, gas can be easily charged and replenished using a single gas pipe 16 that does not require branching. The fourth flange 31B, compared to the first flange 3A of the first embodiment, requires a larger thickness since the vacuum valve 1 and the like are fixed thereto and the fourth flange 31B is subjected to high mechanical shock and high pressure. However, the third flange 31A is subjected to only the low pressure of the intermediate chamber 4, so it can be thinned to a thickness sufficient to hold the seal portion. In addition, since the intermediate chamber 4 is formed outside the tank 5, the height dimension of the tank 5 can be reduced.

[0057] In the seventh embodiment, the fourth flange 31B is fixed to the tank 5 as a flat flange plate, and the third flange 31A is fixed to this fourth flange 31B, thereby providing the intermediate chamber 4 outside the tank 5. By providing the intermediate chamber 4 outside the tank 5, the height of the tank 5 is reduced. As a method of providing the intermediate chamber 4 outside the tank 5, for example, in embodiment 1, the second flange 3B can be installed as a flat flange plate at the opening of the tank 5, and the first flange 3A, which has a convex shape at the top, can be installed on top of the second flange 3B, thereby providing the intermediate chamber 4 outside the tank 5.

[0058] As described above, the vacuum circuit breaker of the seventh embodiment provides a low-pressure space between the high pressure of the insulating gas and the vacuum, thereby realizing a structure that suppresses deformation of the flange and bellows due to pressure sharing and enables gas charging and replenishment. Furthermore, gas can be charged and replenished by a single gas pipe for this three-phase low-pressure space. Also, the height of the tank can be reduced.

[0059] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not exemplified are assumed within the scope of the technology disclosed in this specification, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment. [Explanation of symbols]

[0060] 1 vacuum valve, 2 bellows, 3A first flange, 3B second flange, 4 intermediate chamber, 5 tank, 6 operating mechanism, 6a, 6b three-phase branch section, 7 insulating tube, 7a insulator, 7b plug, 7c plug, 8 movable side connecting conductor, 9 movable side bus conductor, 10 fixed side bus conductor, 11 fixed side connecting conductor, 12 support insulator, 14 sliding seal, 16 gas piping, 21 bellows, 21a bellows body, 21b bellows mounting flange, 22 insulator flange, 22a insulator, 22b plug, 31A third flange, 31B fourth flange, 100, 200, 300, 400, 500, 600, 700 vacuum circuit breaker.

Claims

1. A vacuum circuit breaker comprising: a vacuum valve equipped with a bellows for maintaining a vacuum; a tank for accommodating said vacuum valve; a flange attached to an opening of said tank to form a space for sealing high-pressure insulating gas; and an operating mechanism installed outside said tank for operating the opening and closing of said vacuum valve, the flanges are composed of a first flange on the atmosphere side outside the tank and a second flange on the insulating gas side inside the tank, and an intermediate chamber is formed between the first flange and the second flange; The vacuum valve is fixed to the second flange via an insulating cylinder, the intermediate chamber, the interior of the insulating cylinder, and the interior of the bellows of the vacuum valve are in communication with each other, and the pressure therein is set to an intermediate pressure between the gas pressure of the insulating gas and atmospheric pressure; a gas pipe for supplying gas to the intermediate chamber, the gas pipe being provided outside the tank;

2. 2. The vacuum circuit breaker according to claim 1, wherein the operating mechanism and the flange are provided below the tank.

3. 3. The vacuum circuit breaker according to claim 1, wherein a sliding seal is used to maintain airtightness at a contact portion between the operating mechanism and the operating mechanism opening provided in the first flange.

4. 3. The vacuum circuit breaker according to claim 1, wherein a bellows is used to maintain airtightness at a contact portion between the operating mechanism and the operating mechanism opening provided in the first flange.

5. 3. The vacuum circuit breaker according to claim 1, wherein the second flange and the insulating cylinder are integrally formed.

6. 3. The vacuum circuit breaker according to claim 1, wherein the intermediate chamber is provided inside the tank.

7. 3. The vacuum circuit breaker according to claim 1, wherein the intermediate chamber is provided outside the tank.

8. 3. The vacuum circuit breaker according to claim 1, which is a single-phase circuit breaker including one vacuum valve.

9. 3. The vacuum circuit breaker according to claim 1, wherein the vacuum circuit breaker is a three-phase circuit breaker having three vacuum valves.

10. 10. The vacuum circuit breaker according to claim 9, wherein a three-phase branching section for branching the operating mechanism into three phases is provided in the intermediate chamber.

11. A vacuum circuit breaker comprising: a vacuum valve equipped with a bellows for maintaining a vacuum; a tank for storing said vacuum valve; a flange attached to an opening of said tank to form a space for sealing high-pressure insulating gas; and an operating mechanism installed outside said tank for operating the opening and closing of said vacuum valve, the flanges are composed of a first flange on the atmosphere side outside the tank and a second flange on the insulating gas side inside the tank, and an intermediate chamber is formed between the first flange and the second flange; The vacuum valve is fixed to the second flange via an insulating cylinder, the intermediate chamber, the interior of the insulating cylinder, and the interior of the bellows of the vacuum valve are in communication with each other, and the pressure therein is set to an intermediate pressure between the gas pressure of the insulating gas and atmospheric pressure; A vacuum circuit breaker configured such that the intermediate chamber is provided outside the tank.

12. A vacuum circuit breaker comprising: a vacuum valve equipped with a bellows for maintaining a vacuum; a tank for storing said vacuum valve; a flange attached to an opening of said tank to form a space for sealing high-pressure insulating gas; and an operating mechanism installed outside said tank for operating the opening and closing of said vacuum valve, the flanges are composed of a first flange on the atmosphere side outside the tank and a second flange on the insulating gas side inside the tank, and an intermediate chamber is formed between the first flange and the second flange; The vacuum valve is fixed to the second flange via an insulating cylinder, the intermediate chamber, the interior of the insulating cylinder, and the interior of the bellows of the vacuum valve are in communication with each other, and the pressure therein is set to an intermediate pressure between the gas pressure of the insulating gas and atmospheric pressure; It is a three-phase type with three vacuum valves, A vacuum circuit breaker configured such that a three-phase branching section that branches the operating mechanism into three phases is provided in the intermediate chamber.

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