JP2011014285A - Vacuum valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To moderate an electric field on a contact surface of a vacuum valve, to restrain irregular discharge, and to enhance a withstand voltage characteristic.SOLUTION: This vacuum valve includes a vacuum insulating container 1, a fixed side sealing fitting 2 and a movable side sealing fitting 3 sealed respectively to both end opening parts of the vacuum insulating container 1, a fixed side electrification shaft 4 penetrated through and fixed to the fixed side sealing fitting 2, a fixed side contact 5 fixed to a fixed side electrification shaft 4 end, a fixed side insulating shield 6 for surrounding a side face of the fixed side contact 5 with a prescribed clearance, a movable side contact 7 contacting and separated with/from the fixed side contact 5, a movable side electrification shaft 8 for fixing the movable side contact 7, and for penetrating movably the movable side sealing fitting 3 therethrough, a movable side insulating shield 11 for surrounding a side face of the movable side contact 7 with a prescribed clearance, when the movable side contact 7 is located in an electrode opening position, and an freely extendable bellows 9 of which the one end is sealed to an intermediate part of the movable side electrification shaft 8 and of which the other end is sealed to the movable side sealing fitting 3.

Description

  The present invention relates to a vacuum valve having a pair of contactable and separable contacts, and more particularly to a vacuum valve that can suppress irregular discharge between the contacts and improve the withstand voltage characteristics.

  Conventionally, when a vacuum valve is used for a disconnector, a minute protrusion is formed on the contact surface due to no-load switching etc., the electric field is concentrated locally, and the discharge start between the contacts causes an irregular phenomenon. I sometimes woke up. In order to solve this problem, it is known that a metal member is provided on the outer periphery of the contact to reduce the electric field so that irregular discharge hardly occurs even if a minute protrusion is formed on the contact surface. (For example, refer to Patent Document 1).

JP 2003-92051 A (Page 3, FIG. 1)

  The above-described conventional vacuum valve has the following problems. By providing the metal member on the outer periphery of the contact, the electric field on the contact surface can be reduced, but the electric field strength of the metal member itself increases. Even when the metal member is not mechanically impacted when the contact is opened and closed and a minute protrusion is not formed, the variation in breakdown voltage in vacuum is about 10%, which is larger than that in air or SF6 gas. If the variation is large, the gap length must be increased in order to reduce the probability of destruction, and the vacuum valve becomes larger.

  For this reason, there has been a demand for a member that replaces the metal member to reduce the electric field and hardly cause irregular discharge even if a minute protrusion is formed on the contact surface. Here, the member that replaces the metal member is preferably an insulating member that does not easily emit electrons from itself when it reaches a critical electric field and does not directly contribute to the start of discharge.

  The present invention has been made to solve the above-described problems, and provides a vacuum valve that can reduce the electric field on the contact surface with an insulating member, suppress irregular discharge between the contacts, and improve the withstand voltage characteristics. Objective.

  In order to achieve the above object, a vacuum valve according to the present invention includes a vacuum insulating container having openings at both ends, and a fixed-side sealing metal fitting and a movable-side sealing metal fitting respectively sealed at both end openings of the vacuum insulating container. A fixed-side energizing shaft that is fixedly penetrated to the fixed-side sealing metal fitting, a fixed-side contact that is fixed to the end of the fixed-side energizing shaft, and a fixed that surrounds the side surface of the fixed-side contact with a predetermined gap. A side insulation shield, a movable side contact contacting and separating from the fixed side contact, a movable side energizing shaft that fixes the movable side contact and movably penetrates the movable side sealing bracket, and the movable side contact When in the open position, one end is sealed to the middle portion of the movable side conductive shield and the movable side energizing shaft surrounding the side surface with a predetermined gap, and the other end is sealed to the movable side sealing bracket. Specially equipped with a retractable bellows To.

  According to the present invention, since the contact is surrounded by the insulation shield with a predetermined gap, the electric field on the contact surface can be reduced, and irregular discharge between the contacts is suppressed to improve the withstand voltage characteristic. be able to.

Sectional drawing which shows the structure of the vacuum valve which concerns on Example 1 of this invention. Sectional drawing which shows the structure of the vacuum valve which concerns on Example 2 of this invention. Sectional drawing which shows the structure of the vacuum valve which concerns on Example 3 of this invention. The top view which shows the insulation shield used for the vacuum valve which concerns on Example 3 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a vacuum valve according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a configuration of a vacuum valve according to Embodiment 1 of the present invention.

  As shown in FIG. 1, a fixed-side sealing metal fitting 2 and a movable-side sealing metal fitting 3 are respectively sealed at both end openings of a cylindrical vacuum insulating container 1 made of ceramics such as alumina porcelain. A fixed-side energizing shaft 4 is penetrated and fixed at the center of the fixed-side sealing fitting 2, and a fixed-side contact 5 is fixed to a surface orthogonal to the axial direction of the inner end portion of the vacuum insulating container 1.

  An annular fixed side insulating shield 6 made of an inorganic insulating material such as ceramics or mica that surrounds the outer periphery of the side surface of the fixed side contact 5 is provided on the outer periphery of the fixed side energizing shaft 4 through a metallization layer (not shown). It is fixed by brazing. The inner diameter of the fixed-side insulation shield 6 is larger than the outer diameter of the fixed-side contact 5 so that a gap of about 2 mm is maintained. The tip is a curved surface with a semicircular cross section, and protrudes about 5 mm from the fixed contact point 5 surface to the movable side.

  A movable contact 7 that can be moved toward and away from the fixed contact 5 is fixed to a surface perpendicular to the axial direction of the end of the movable energizing shaft 8 that movably penetrates the central opening of the movable seal 3. Has been. One end of a telescopic bellows 9 is sealed at an intermediate portion of the movable side energizing shaft 8, and the other end is sealed at a central opening of the movable side sealing fitting 3. Thereby, the movable side energizing shaft 8 can be moved in the axial direction while maintaining the vacuum in the vacuum insulating container 1.

  One end of a cylindrical support fitting 10 is fixed to the outer periphery of the bellows 9 of the movable side sealing fitting 3. Similarly to the fixed side, an annular movable insulating shield 11 made of an inorganic insulating material is fixed to the other end by brazing or the like through a metallization layer (not shown). The inner diameter of the movable-side insulating shield 11 is larger than the outer diameter of the movable-side contact 7 and the movable-side conductive shaft 8 and is arranged so as to surround the outer periphery of the side surface of the movable-side contact 7 with a gap of about 2 mm. Further, the tip is a curved surface, and when the movable contact 7 reaches the open position, it protrudes about 5 mm from the surface of the movable contact 7 to the fixed side.

  A cylindrical arc shield 12 surrounding the fixed side contact 5 and the movable side contact 7 and between the fixed side insulating shield 6 and the movable side insulating shield 11 is fixed to the intermediate portion of the inner surface of the vacuum insulating container 1. Yes.

  Thereby, the fixed side contact 5 and the movable side contact 7 are provided with the fixed side insulating shield 6 and the movable side insulating shield 11, so that the electric field can be reduced. In particular, when a minute protrusion is formed on the surface of the contact 5 or 7 by no-load switching or the like, the electric field increases, but the dielectric breakdown may occur from the peripheral portion rather than the plane where the contacts 5 and 7 face each other. Many. Dielectric breakdown causes uneven electric field formation of minute protrusions and is liable to cause irregular discharge. However, since a dielectric projecting from the contact surfaces 5 and 7 is close to the peripheral portion, the electric field rise is suppressed. be able to. When the dielectric constants of the insulating shields 6 and 11 are 6 to 11, the electric field strength can be suppressed by about 10 to 20%, and the variation in discharge can be reduced.

  In addition, since the clearance gap between the contacts 5 and 7 and the insulation shields 6 and 11 is maintained at a predetermined value, it is possible to prevent an electric field increase due to triple point coupling. Further, when the movable contact 7 is at the open position, the shortest gap is formed between the insulating shields 6 and 11, but the dielectrics are opposed to each other, and the withstand voltage characteristic is not deteriorated. Furthermore, since the insulating shields 6 and 11 are made of an inorganic insulating material, they do not emit an impure gas in a vacuum, have heat resistance, have a cooling effect on the arc, and exhibit excellent characteristics.

  According to the vacuum valve of the first embodiment, since the fixed side insulating shield 6 and the movable side insulating shield 11 surrounding the fixed side contact 5 and the movable side contact 7 are provided, the fixed side contact 5 and the movable side contact are provided. 7, particularly the electric field of the peripheral edge can be reduced, irregular discharge can be suppressed, and the withstand voltage characteristics can be improved.

  Next, a vacuum valve according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a configuration of a vacuum valve according to Embodiment 2 of the present invention. The second embodiment is different from the first embodiment in the method for fixing the movable insulating shield. In FIG. 2, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 2, the movable insulating shield 11 is fixed to the outer periphery of the end of the movable energizing shaft 8. The inner diameter of the movable insulating shield 11 is larger than the outer diameter of the fixed insulating shield 6 so that when the fixed contact 5 and the movable contact 7 come into contact with each other, they do not come into contact with each other. Conversely, the inner diameter of the fixed insulating shield 6 may be larger than the outer diameter of the movable insulating shield 11.

  According to the vacuum valve of the second embodiment, the same effect as that of the first embodiment can be obtained. When the movable insulating shield 11 moves, mechanical strength is applied to the portion fixed to the movable conductive shaft 8, so that it is preferably applied to a switch such as a disconnector whose switching speed is slower than the circuit breaker. .

  Next, a vacuum valve according to Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 3 is a sectional view showing the configuration of the vacuum valve according to the third embodiment of the present invention, and FIG. 4 is a top view showing an insulation shield used in the vacuum valve according to the third embodiment of the present invention. The third embodiment is different from the first embodiment in the fixing method of the insulation shield on the fixed side and the movable side. 3 and 4, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, the fixed-side insulating shield 13 and the movable-side insulating shield 14 are provided on the outer circumferences of the annular cylinder portions 13 a and 14 a surrounding the outer circumference of the side surfaces of the contacts 5 and 7 and the cylinder portions 13 a and 14 a. It is divided into disk-shaped support portions 13b and 14b. The outer peripheries of the support portions 13b and 14b are fixed to the inner surface of the arc shield 12 at a predetermined interval by brazing or the like via a metallization layer (not shown).

  Further, as shown in FIG. 4, the support portions 13 b and (14 b) are formed with openings 13 b 1 and (14 b 1) so that the metal vapor generated between the contacts 5 and 7 is diffused into the vacuum insulating container 1. It has become. The inner diameters of the cylindrical portions 13a and (14a) are larger than the outer diameters of the contacts 5 and (7), and a predetermined gap is maintained, as in the movable insulating shield 11 of the first embodiment.

  According to the vacuum valve of the third embodiment, in addition to the same effects as those of the first embodiment, since the insulation shields 13 and 14 have the same shape, they can be mass-produced and manufactured easily.

DESCRIPTION OF SYMBOLS 1 Vacuum insulating container 2 Fixed side sealing metal fitting 3 Movable side sealing metal fitting 4 Fixed side energizing shaft 5 Fixed side contact 6 and 13 Fixed side insulation shield 7 Movable side contact 8 Movable side energizing shaft 9 Bellows 10 Support metal fittings 11 and 14 Movable Side insulation shield 12 Arc shield 13a, 14a Tube part 13b, 14b Support part

Claims (5)

A vacuum insulating container having openings at both ends;
A fixed-side sealing metal fitting and a movable-side sealing metal fitting respectively sealed at both ends of the vacuum insulating container;
A fixed-side energizing shaft that is fixedly penetrated to the fixed-side sealing fitting;
A fixed-side contact fixed to the fixed-side energizing shaft end;
A fixed-side insulating shield that surrounds the side surface of the fixed-side contact with a predetermined gap; and
A movable contact that contacts and separates from the fixed contact;
A movable side energizing shaft that sticks the movable side contact and movably penetrates the movable side sealing bracket,
When the movable contact is in the open position, a movable insulating shield that surrounds the side surface with a predetermined gap;
A vacuum valve comprising: a telescopic bellows having one end sealed at an intermediate portion of the movable side energizing shaft and the other end sealed by the movable side sealing metal fitting. Fixing the stationary insulating shield to the outer periphery of the stationary energizing shaft end;
The vacuum valve according to claim 1, wherein the movable insulating shield is fixed to a support fitting fixed to the movable sealing fitting. One insulation shield is fixed to the outer periphery of one energizing shaft end,
Fix the other insulation shield to the outer circumference of the other energizing shaft end,
The vacuum valve according to claim 1, wherein an inner diameter of the other insulating shield is larger than an outer diameter of the one insulating shield.   The vacuum valve according to claim 1, wherein the fixed-side insulating shield and the movable-side insulating shield are fixed to an inner surface of an arc shield surrounding the fixed-side contact and the movable-side contact.   The vacuum valve according to any one of claims 1 to 4, wherein the fixed-side insulating shield and the movable-side insulating shield are formed of an inorganic insulating material.

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