vacuum valve

Abstract

To make it easy to measure the degree of vacuum.SOLUTION: A vacuum valve 10 includes a vacuum container 100, a fixed electrode 110 and a movable electrode 120 housed in the vacuum container 100, and a coil 140 that is provided in the vacuum container 100, is wound around the fixed electrode 110 and the movable electrode 120, and is used for measuring the degree of vacuum using a magnetron method.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a vacuum valve.

Background Art

[0002] One method for measuring the degree of vacuum of a vacuum valve is a magnetron method corresponding to the measurement of the degree of vacuum in a high-vacuum region. The magnetron method is a method of calculating the degree of vacuum by applying a magnetic field between a pair of electrodes arranged in a vacuum container while applying a voltage between the electrodes and measuring the discharge current flowing between the electrodes. As a configuration for applying a magnetic field between the electrodes, for example, Patent Document 1 discloses a configuration in which a cable is wound around the periphery of a vacuum interrupter of a solid insulation switchgear.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Vacuum valves are generally installed on-site in a state incorporated into other devices such as opening and closing devices. Also, depending on the incorporation mode of the vacuum valve, there are often cases where sufficient clearance is not ensured on the outer periphery of the vacuum valve. Therefore, when measuring the degree of vacuum using the technique disclosed in Patent Document 1, workers etc. cannot easily wind the cable for vacuum degree measurement around the vacuum valve at the installation site, and cannot easily measure the degree of vacuum. In view of the above circumstances, the present disclosure aims to facilitate the measurement of the degree of vacuum.

Means for Solving the Problems

[0005] Above ofTo solve the problem, a vacuum valve according to one aspect of the present disclosure comprises a vacuum vessel, a fixed electrode and a movable electrode housed in the vacuum vessel, and a coil provided inside the vacuum vessel, wound around the fixed electrode and the movable electrode, and used for measuring the degree of vacuum by a magnetron. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic diagram of a vacuum level measurement system having a vacuum valve according to an embodiment. [Figure 2] This diagram schematically shows the internal structure of a vacuum valve. [Figure 3] This diagram shows the configuration of the intermediate shield. [Figure 4] This is a schematic diagram of the first and second energizing terminals. [Figure 5] This figure shows the configuration of the intermediate shield in a modified example. [Figure 6] This is an explanatory diagram of the intermediate shield and coil in a modified example. [Figure 7] This is an explanatory diagram of the intermediate shield and coil in a modified example. [Modes for carrying out the invention]

[0007] The embodiments for implementing this disclosure will be described with reference to the drawings. Note that the dimensions and scale of the elements in each drawing may differ from those of the actual product. Furthermore, the embodiments described below are illustrative examples of embodiments that may be envisioned when implementing this disclosure. Therefore, the scope of this disclosure is not limited to the embodiments exemplified below.

[0008] 1: Embodiment Figure 1 is a schematic diagram of a vacuum level measurement system 1 having a vacuum valve 10 according to this embodiment. Figure 2 is a schematic diagram showing the internal configuration of the vacuum valve 10. As shown in Figure 1, the vacuum level measurement system 1 comprises a vacuum valve 10 and a measuring device 20. The vacuum valve 10 is used, for example, in a power supply network as a switchgear (also called a vacuum circuit breaker) that switches between supplying and interrupting power. As shown in Figure 2, the vacuum valve 10 comprises a vacuum vessel 100 whose interior is maintained under vacuum, and a fixed electrode 110 and a movable electrode 120 housed in the vacuum vessel 100. The fixed electrode 110 and the movable electrode 120 are electrically connected to the network. The fixed electrode 110 and the movable electrode 120 are so-called normally closed contacts. That is, when the movable electrode 120 separates from the fixed electrode 110, the current flow between the fixed electrode 110 and the movable electrode 120 is interrupted by the high insulating performance of the vacuum. When this current is interrupted, the arc generated between the fixed electrode 110 and the movable electrode 120 is quickly extinguished by the insulating recovery performance of the vacuum. Furthermore, the contact and separation of the movable electrode 120 with respect to the fixed electrode 110 is controlled by an insulating movable member provided outside the vacuum valve 10, which moves the movable electrode 120 according to the state of the circuit network (for example, an abnormal condition), as shown in Figure 1.

[0009] As shown in Figure 1, the measuring device 20 is electrically connected to the vacuum valve 10 and measures the vacuum level of the vacuum valve 10 using a magnetron method. The magnetron method involves applying a DC voltage V1 to the fixed electrode 110 and the movable electrode 120, applying a magnetic field to the fixed electrode 110 and the movable electrode 120 using a coil 140 (described later), measuring the DC current Ah flowing between the fixed electrode 110 and the movable electrode 120, and measuring the vacuum level inside the vacuum container 100 based on this measured value of DC current Ah. This measured value of DC current Ah is proportional to the electron multiplication number, i.e., the molecular density (pressure inside the vacuum container 100), and the vacuum level is calculated from the measured value of DC current Ah using this proportional relationship.

[0010] To realize the above-described magnetron method measurement, the measuring device 20 includes a DC voltage source 210, a DC current source 220, and a DC ammeter 230, as shown in Figure 1. The DC voltage source 210 is a voltage source that applies a DC voltage V1 between the fixed electrode 110 and the movable electrode 120. The DC current source 220 is a current source that supplies a DC current A1 to the coil 140 in order to generate a magnetic field in the coil 140. The DC ammeter 230 is an ammeter that measures the DC current Ah flowing between the fixed electrode 110 and the movable electrode 120. The DC voltage V1 from the DC voltage source 210 is supplied to the vacuum valve 10 via the first cable CA1 and the second cable CA2, and the DC current A1 from the DC current source 220 is supplied to the vacuum valve 10 via the third cable CA3 and the fourth cable CA4. Note that it is appropriate to determine which of the first cable CA1 and the second cable CA2 and which of the third cable CA3 and the fourth cable CA4 is the cathode.

[0011] Next, the configuration of the vacuum valve 10 will be described in detail. As shown in Figure 2, the vacuum vessel 100 of the vacuum valve 10 comprises a substantially cylindrical insulating container 101 with both ends open, a first metal housing 102 that closes one opening 101A of the insulating container 101, and a second metal housing 103 that closes the other opening 101B of the insulating container 101. The insulating container 101 is a container mainly made of ceramic, such as alumina porcelain, and has high insulating performance. The first metal housing 102 and the second metal housing 103 are metal flanges and are hermetically joined to the insulating container 101, for example, by brazing or fusion. The inside of the vacuum vessel 100 is maintained under vacuum, and the degree of vacuum is 10 -1 Pa to 10 -5 Pressure in the high vacuum region of Pa (e.g., 6.7 × 10⁻⁶) -2 It is listed as Pa).

[0012] Furthermore, as shown in Figure 2, the vacuum valve 10 comprises a first energizing shaft 112, a second energizing shaft 122, and an intermediate shield 130. The first current-carrying shaft 112 and the second current-carrying shaft 122 support the fixed electrode 110 and the movable electrode 120 housed in the vacuum vessel 100 and are members for conducting the voltage supplied from the outside. Specifically, the first current-carrying shaft 112 is a columnar member made of a conductive material to which the fixed electrode 110 is joined at one end 112A. The first current-carrying shaft 112 penetrates from the inside to the outside through the substantially central portion of the first metal housing 102 of the vacuum vessel 100 and is fixed to the first metal housing 102. The first current-carrying shaft 112 includes a first terminal portion 112T having a diameter-expanded shape at the end protruding from the first metal housing 102, and during vacuum degree measurement, the first cable CA1 of the measuring device 20 is connected to the first terminal portion 112T. The second current-carrying shaft 122 is a columnar member made of a conductive material to which the movable electrode 120 is joined at one end 122A. The second current-carrying shaft 122 penetrates from the inside to the outside through the substantially central portion of the second metal housing 103 of the vacuum vessel 100 and is provided movably along the central axis C with respect to the second metal housing 103. The second current-carrying shaft 122 includes a second terminal portion 122T having a diameter-expanded shape at the end protruding from the second metal housing 103, and during vacuum degree measurement, the second cable CA2 of the measuring device 20 is connected to the second terminal portion 122T. The first current-carrying shaft 112 and the second current-carrying shaft 122 are arranged coaxially with the central axis C of the vacuum vessel 100 in a posture where the fixed electrode 110 and the movable electrode 120 face each other inside the vacuum vessel 100.

[0013] The intermediate shield 130 is a metal member that surrounds the fixed electrode 110 and the movable electrode 120 and is fixed to the inner surface of the vacuum vessel 100. The intermediate shield 130 is also a member called an arc shield, captures the metal vapor generated between the fixed electrode 110 and the movable electrode 120 during current interruption, and prevents the metal vapor from adhering to the inner surface of the insulating vessel 101. By preventing the adhesion of the metal vapor, it is prevented that the insulating performance of the insulating vessel 101 is impaired.

[0014] FIG. 3 is a diagram showing the configuration of the intermediate shield 130 together with the fixed electrode 110 and the movable electrode 120, and the first current-carrying shaft 112 and the second current-carrying shaft 122. The intermediate shield 130 has a cylindrical shape with both ends open and is arranged coaxially with the central axis C of the vacuum vessel 100 in the same manner as the first current-carrying axis 112 and the second current-carrying axis 122 as shown in FIG. 3. A slit 132 is formed in the intermediate shield 130 that extends between one end and the other end while rotating around the central axis C, or in other words, extends spirally. One end is hereinafter referred to as the "first end 130TA", and the other end is hereinafter referred to as the "second end 130TB". In the intermediate shield 130, the range in which the slit 132 is formed functions as a coil 140 formed by spirally winding a single thin strip-shaped conductive wire. During vacuum measurement, a direct current A1 is supplied from a measuring device 20 outside the vacuum valve 10 to the coil 140, and the coil 140 becomes a magnetic field generation source.

[0015] However, when the slit 132 is formed in the intermediate shield 130, the metal vapor generated at the time of current interruption between the fixed electrode 110 and the movable electrode 120 may pass through the slit 132 and adhere to the inner surface of the insulating container 101. Therefore, in order to suppress the passage of metal vapor, it is desirable that the width WS of the slit is 1 mm or less. Further, by restricting the width WS to 1 mm or less, the electric field concentration near the fixed electrode 110 and the movable electrode 120 and on the surface of the intermediate shield 130 is suppressed to a certain level or less.

[0016] As shown in FIG. 2, the vacuum valve 10 includes a first current path 151 and a second current path 152 for flowing a current from the outside of the vacuum valve 10 to the internal coil 140. The first current path 151 is a current path that conducts electricity between the coil end 140TA corresponding to the first end 130TA in the coil 140 and the outside of the vacuum vessel 100. The second current path 152 is a current path that conducts electricity between the coil end 140TB corresponding to the second end 130TB in the coil 140 and the outside of the vacuum vessel 100.

[0017] The first current path 151 comprises a first energizing terminal 1510 and a first wire 1512, and the second current path 152 comprises a second energizing terminal 1520 and a second wire 1522. The first energizing terminal 1510 and the second energizing terminal 1520 are terminal members that are exposed on the outside of the vacuum vessel 100 and are used as electrical contacts with the third cable CA3 and the fourth cable CA4 extending from the measuring device 20. As shown in Figure 1, both the first energizing terminal 1510 and the second energizing terminal 1520 are exposed in a band shape around the entire circumference of the surface of the vacuum vessel 100, and the contacts CA3C and CA4C at the ends of the third cable CA3 and the fourth cable CA4, respectively, are electrically connected to the respective exposed locations. As shown in Figure 2, the first wire 1512 is a conductive member that extends through the vacuum container 100 between the first energizing terminal 1510 and the coil end 140TA, electrically connecting the two. The second wire 1522 is a conductive member that extends through the vacuum container 100 between the second energizing terminal 1520 and the coil end 140TB, electrically connecting the two. In addition, by using members with a predetermined rigidity for the first wire 1512 and the second wire 1522, the first wire 1512 and the second wire 1522 may be used as support members for the intermediate shield 130.

[0018] Figure 4 is a schematic diagram of the first energizing terminal 1510 and the second energizing terminal 1520. As shown in Figure 4, both the first energizing terminal 1510 and the second energizing terminal 1520 are annular metal members of a predetermined thickness. The outer diameters of the first energizing terminal 1510 and the second energizing terminal 1520 are greater than or equal to the outer diameter of the vacuum vessel 100, and the outer surfaces 1510A and 1520A of the first energizing terminal 1510 and the second energizing terminal 1520 are exposed either flush with the outer surface of the vacuum vessel 100 (so-called flush surface) or protruding from the outer surface. The exposed surfaces, including the outer surfaces 1510A and 1520A, become contact points with the contacts CA3C and CA4C of the third cable CA3 and the fourth cable CA4.

[0019] In the vacuum vessel 100, as shown in Figures 1, 2, and 4, an insulating annular insulating spacer 1530 is provided between the first energizing terminal 1510 and the second energizing terminal 1520, ensuring insulation between the first energizing terminal 1510 and the second energizing terminal 1520. As shown in Figure 1, the first energizing terminal 1510, the insulating spacer 1530, and the second energizing terminal 1520 constitute a three-layer laminated structure 1540 in the vacuum vessel 100. As shown in Figure 2, the insulating vessel 101 is divided in the direction in which the central axis C extends into a first vessel body 1011 to which the first metal housing 102 is joined, and a second vessel body 1012 to which the second metal housing 103 is joined. The laminated structure 1540 is sandwiched between the first container body 1011 and the second container body 1012, thereby incorporating the laminated structure 1540 into the vacuum container 100. Since the first power supply terminal 1510 and the second power supply terminal 1520 are annular laminated structure 1540, compared to a configuration in which rod-shaped power supply terminals penetrate the insulating container 101 from the inside to the outside, there are no irregularities on the joint surface between the first power supply terminal 1510 and the second power supply terminal 1520 and the first container body 1011 and the second container body 1012, making it easier to manage the airtightness of the joint surface.

[0020] In the above configuration, when measuring the vacuum level using the magnetron method, as shown in Figure 1, the first cable CA1, second cable CA2, third cable CA3, and fourth cable CA4 of the measuring device 20 are electrically connected to the vacuum valve 10 by a worker or the like. Specifically, of the first cable CA1 and second cable CA2 extending from the DC voltage source 210, the first cable CA1 is connected to the first terminal 112T of the first energizing shaft 112, and the second cable CA2 is connected to the second terminal 122T of the second energizing shaft 122. Also, of the third cable CA3 and fourth cable CA4 extending from the DC current source 220, the third cable CA3 is connected to the first energizing terminal 1510, and the fourth cable CA4 is connected to the second energizing terminal 1520.

[0021] The measuring device 20 then supplies a DC current A1 from the DC current source 220 to the coil 140 of the intermediate shield 130 through the first energizing terminal 1510 and the second energizing terminal 1520. As the DC current A1 flows through the coil 140, a DC magnetic field is generated in the direction connecting the fixed electrode 110 and the movable electrode 120 (the direction of the central axis C) according to Ampere's law, and this magnetic field is applied between the fixed electrode 110 and the movable electrode 120. With this magnetic field applied, the measuring device 20 supplies a DC voltage V1 from the DC voltage source 210 to the fixed electrode 110 and the movable electrode 120 through the first terminal section 112T and the second terminal section 122T. The measuring device 20 then measures the DC current Ah flowing between the fixed electrode 110 and the movable electrode 120 when the DC voltage V1 is applied using a DC ammeter 230, and calculates the degree of vacuum based on this measurement result.

[0022] In measuring vacuum using the magnetron method, the stronger the magnetic field applied between the fixed electrode 110 and the movable electrode 120, the larger the DC current Ah flowing between the fixed electrode 110 and the movable electrode 120, making measurement easier. The strength of the magnetic field generated by the coil 140 is proportional to the DC current A1 flowing through the coil 140 and the number of turns of the coil 140, respectively. Therefore, the measuring device 20 strengthens the magnetic field by setting the DC current A1 supplied from the DC current source 220 to a large current of 50 A (amperes) or more. However, when a large current is supplied from the DC current source 220, damage to the contacts may occur depending on the size of the contact area between the contacts CA3C and CA4C of the third cable CA3 and the fourth cable CA4 and the first energizing terminal 1510 and the second energizing terminal 1520 of the vacuum valve 10. Therefore, at the first energizing terminal 1510 and the second energizing terminal 1520, the portion exposed from the vacuum valve 10 has a contact area of ​​10 mm² with contacts CA3C and CA4C. 2 The dimensions are such that the above area is secured. In addition, in the vacuum container 100, the number of turns of the coil 140 is 5 or more in order to strengthen the magnetic field.

[0023] As described above, the vacuum valve 10 comprises a vacuum container 100, a fixed electrode 110 and a movable electrode 120 housed in the vacuum container 100, and a coil 140 provided inside the vacuum container 100, wound around the fixed electrode 110 and the movable electrode 120, and used for measuring the vacuum level using a magnetron method. Since the coil 140 is pre-installed inside the vacuum valve 10, there is no need to wind a separate coil around the vacuum container 100 when measuring the vacuum level, as in the technology described in Patent Document 1. Therefore, even if the vacuum valve 10 is installed in a state where it is incorporated into other devices such as an opening and closing device, and there is not enough space around the vacuum valve 10, an operator can easily measure the vacuum level using the coil 140 in the vacuum container 100. Furthermore, vacuum level measurement is generally also performed during the shipment test of the vacuum valve 10. In this case as well, since there is no need to wind a coil around the vacuum container 100, vacuum level measurement becomes easier.

[0024] Furthermore, the vacuum valve 10 is installed inside the vacuum container 100 and is equipped with a metal intermediate shield 130 that surrounds the fixed electrode 110 and the movable electrode 120, and the intermediate shield 130 functions as a coil 140. Therefore, when measuring the vacuum level, the vacuum level can be measured using the magnetron method by passing a DC current A1 through the intermediate shield 130. coil Since it functions as 140, there is no need to provide a separate coil from the intermediate shield 130, thus reducing the number of parts.

[0025] Furthermore, the intermediate shield 130 is provided with slits 132 that extend spirally around the fixed electrode 110 and the movable electrode 120, forming a coil 140. This simple configuration, with slits 132 formed in the intermediate shield 130, allows the intermediate shield 130 to function as a coil 140.

[0026] Furthermore, since the width WS of the slit 132 is 1 mm or less, metal vapor generated when current is interrupted between the fixed electrode 110 and the movable electrode 120 can pass through the slit 132 and is prevented from adhering to the inner surface of the insulating container 101. In addition, electric field concentration near the fixed electrode 110 and the movable electrode 120, as well as on the surface of the intermediate shield 130, is suppressed to a certain level or lower.

[0027] Furthermore, since the slit 132 winds around the fixed electrode 110 and the movable electrode 120 five or more times, a sufficiently strong magnetic field can be obtained by the coil 140, making it easy to measure the degree of vacuum using the magnetron method. However, if, for example, a sufficiently strong magnetic field can be obtained by increasing the DC current A1, the number of turns may be less than five.

[0028] Furthermore, since the vacuum valve 10 is electrically connected to the coil 140 inside the vacuum container 100 and has a first energizing terminal 1510 and a second energizing terminal 1520 exposed outside the vacuum container 100, a DC current A1 can be easily supplied to the coil 140 by connecting the contacts CA3C and CA4C of the third cable CA3 and fourth cable CA4 of the measuring device 20 to the first energizing terminal 1510 and the second energizing terminal 1520.

[0029] Furthermore, since the first energizing terminal 1510 and the second energizing terminal 1520 are annular in shape extending around the entire circumference of the vacuum container 100, compared to a configuration in which the energizing terminals are rod-shaped and penetrate the insulating container 101 from the inside to the outside, there are no irregularities on the joint surfaces between the first energizing terminal 1510 and the second energizing terminal 1520 and the first container body 1011 and the second container body 1012, making it easier to manage the airtightness of the joint surfaces.

[0030] Furthermore, both the first power terminal 1510 and the second power terminal 1520 have a contact area of ​​10 mm² with contacts CA3C and CA4C of the third cable CA3 and the fourth cable CA4, respectively. 2The dimensions are formed to be as described above. Therefore, even if a large current of, for example, 50A (amperes) or more is supplied from the contacts CA3C and CA4C of the third cable CA3 and the fourth cable CA4 to the first energizing terminal 1510 and the second energizing terminal 1520 in order to obtain a sufficiently strong magnetic field with the coil 140, damage to the contacts between the contacts CA3C and CA4C and the first energizing terminal 1510 and the second energizing terminal 1520 can be prevented. Furthermore, if a DC current A1 sufficient for measuring the vacuum level can be passed, the contact area is 10mm². 2 Less than is also acceptable.

[0031] 2 : Variation The following are examples of specific modifications that may be added to the embodiments illustrated above. Two or more embodiments may be arbitrarily selected from the following examples and combined as appropriate, provided they do not contradict each other.

[0032] (1) In this embodiment, the coil 140 formed on the intermediate shield 130 has a substantially constant winding interval P (so-called pitch) in the direction of the central axis C, but the interval P does not have to be constant. For example, as shown in Figure 5, the winding interval P of the coil 140 may be wider at a location Q corresponding to the space between the fixed electrode 110 and the movable electrode 120 than at other locations. By widening the winding interval P of the coil 140 at this location Q, the area of ​​the slit 132 opening around the space between the fixed electrode 110 and the movable electrode 120 can be reduced or made zero. In other words, the coil 140 can be said to have a configuration comprising a cylindrical portion that surrounds the space between the fixed electrode 110 and the movable electrode 120, a first portion extending from the cylindrical portion to the first coil end 140TA, and a second portion extending from the cylindrical portion to the second coil end 140TB. The configuration of this coil 140 allows the cylindrical portion to suppress the passage of metal vapor generated between the fixed electrode 110 and the movable electrode 120 through the slit 132 when the current is interrupted, thereby preventing it from adhering to the inner surface of the insulating container 101.

[0033] (2) In the embodiment, a configuration in which the intermediate shield 130 functions as a coil 140 has been illustrated. However, the coil 140 may be provided separately from the intermediate shield 130. For example, as shown in Figure 6, the coil 140 wound around the fixed electrode 110 and the movable electrode 120 may be provided inside the intermediate shield 130. Alternatively, as shown in Figure 7, the coil 140 may be provided outside the intermediate shield 130. Also, for example, if the coil 140 can be used instead of the intermediate shield 130, the vacuum valve 10 may not be provided with the intermediate shield 130. [Explanation of Symbols]

[0034] 10...Vacuum valve, 100...Vacuum vessel, 110...Fixed electrode, 120...Movable electrode, 130...Intermediate shield, 132...Slit, 140...Coil, A1, Ah...DC current P ...interval, WS...width.

Claims

1. Vacuum container and The vacuum container comprises a fixed electrode and a movable electrode, A metal intermediate shield surrounds the fixed electrode and the movable electrode inside the vacuum container and functions as a coil used for measuring the degree of vacuum using a magnetron method, A vacuum valve equipped with the following features.

2. The intermediate shield is provided with slits that extend spirally around the fixed electrode and the movable electrode and form the coil. The vacuum valve according to claim 1.

3. The width of the slit is 1 mm or less. The vacuum valve according to claim 2.

4. The number of turns the slit makes around the fixed electrode and the movable electrode is five or more. The vacuum valve according to claim 2.

5. In the location corresponding to the space between the fixed electrode and the movable electrode, the spacing of the windings of the slit is wider than in other locations. The vacuum valve according to claim 2.

6. Vacuum container and The vacuum container comprises a fixed electrode and a movable electrode, A coil is wound around the fixed electrode and the movable electrode inside the vacuum container and is used for measuring the degree of vacuum using a magnetron method. A current-carrying terminal that is electrically connected to the coil inside the vacuum container and exposed outside the vacuum container, A vacuum valve equipped with the following features.

7. The aforementioned power supply terminal is The annular structure extends around the entire circumference of the vacuum container. The vacuum valve according to claim 6.

8. The aforementioned power supply terminal is The contact area of ​​the contact supplying DC current to the coil is 10 mm². ２ That's all. The vacuum valve according to claim 6.

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