JPS639970Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a vacuum switchgear, and in particular, a vacuum container is formed by closing both ends of a metal cylinder with insulating end plates, and a pair of electrodes are connected to the vacuum container from both insulating end plates. This invention relates to a vacuum shield and disconnector which is provided so as to be able to approach and separate via a pair of electrode rods that are introduced so as to be able to move toward and away from each other, and which has increased external insulation strength.

In general, a vacuum shield disconnector is constructed by closing both ends of an insulating cylinder made of glass or ceramic with metal end plates to form a vacuum container, and a pair of electrodes are placed inside the vacuum container relative to each other from both metal end plates. The metal cylinder is constructed so that it can be moved towards and away from the electrodes through a pair of electrode rods that can be moved towards and away from each other.However, in recent years, in order to reduce the size and cost, both ends of the metal cylinder have been replaced with insulating end plates made of ceramic. A vacuum container is formed by closing the vacuum container, and a pair of electrodes are installed in the vacuum container so that they can be moved toward and away from each other through a pair of electrode rods that are introduced from both insulated end plates so that they can move toward and away from each other. Proposed.

However, in the former vacuum shield disconnector, the axial length of the insulating cylinder is the external insulation distance, and the test voltage for each working voltage could be cleared by the vacuum shield disconnector alone, but in the latter vacuum For insulation breakers, the length equivalent to the diameter of the insulation end plate is the external insulation distance.
The external insulation distance is 1/2 that of the former at the same working voltage.
Since the test voltage could no longer be cleared by the vacuum shield or disconnector alone, it was necessary to strengthen the external insulation to match the internal vacuum insulation strength.

The present invention was developed in view of the above-mentioned problems, and its purpose is to make the external insulation strength of a vacuum container made of a metal tube and insulating end plates closing both ends comparable to the internal vacuum insulation strength. It is an object of the present invention to provide a vacuum switchgear which is capable of buffering thermal effects caused by arcs and mechanical shocks during closing and closing operations. Hereinafter, embodiments of this invention will be described in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a vacuum switchgear according to the present invention. In the figure, reference numeral 1 denotes an insulating case made of epoxy resin into a cylindrical shape with a bottom. Inside this insulating case 1, a substantially cylindrical metal cylinder 2 is airtightly closed at both ends with insulating end plates 3 made of ceramic. to form a vacuum container, and a pair of electrode rods 5, in which a pair of electrodes 4, 4 are introduced into the vacuum container from the center of both insulating end plates 3, 3 so as to be able to approach and separate from each other freely;
A vacuum shield breaker 6, which is provided so as to be able to come into contact with and separate from it through the fixed electrode rod 5 (upper side in the figure)
is led out from a hole 7 provided at the center of the bottom of the insulating case 1, and the insulating end plate 3 on the fixed electrode rod 5 side is housed concentrically with an appropriate distance from the bottom of the insulating case 1.

The inner diameter of the insulating case 1 is located on the outer periphery of the metal cylinder 2 near the middle part of the vacuum shield breaker 6, in other words, on the outer periphery of the metal cylinder 2 facing the part where an arc is generated due to contact and separation of the electrodes 4, 4. An air layer 9 is formed by fitting two ring-plate-shaped packings 8 having approximately the same outer diameter as , spaced apart in the axial direction (in the vertical direction in FIG. 1). As will be described later, the air layer 9 is caused by negative effects on the insulating case 1 and the vacuum shield breaker 6, which are integrated through an elastic body, such as local expansion of the elastic body due to arc heat. peeling of the brazed parts,
This is to buffer the breakage of the insulating end plate 3 made of ceramic or the breakage of the insulating case 1 made of epoxy resin by increasing the pressure within the air layer 8, and each packing 8 is made of heat-resistant material. It is made of silicone rubber, urethane rubber, etc., which have excellent properties, or silicone foam, urethane foam, etc. having open or closed cells.
The insulating case 1 and the vacuum shield breaker 6 are made of silicone rubber, polybutadiene rubber, epoxy rubber, etc., which is cast and hardened between them so as to cover the insulating end plate 3 on the movable electrode rod 5 side. They are integrated by an elastic body 10 made of cast liquid rubber with excellent heat resistance and insulation properties.

In the figure, 11 is a bellows, 12 is the bottom of the insulating case 1 and the fixed electrode rod 5 of the vacuum shield breaker 6.
This is a ring-shaped packing that is interposed between the side insulating end plate 3 and fitted onto the fixed electrode rod 5, and is made of insulating rubber and having elasticity comparable to that of the elastic body 10. Further, 13 is a nut screwed onto the fixed electrode rod 5 protruding from the hole 7 of the insulating case 1, and 14 is an injection port provided at the bottom of the insulating case 1 for injecting the cast liquid rubber.

To manufacture the vacuum switchgear having the above configuration, first, two ring plate-shaped packings 8 are spaced apart in the axial direction on the outer periphery of the metal cylinder 2 in the vacuum shield breaker 6 near the middle part. Insert. Next, the packing 12 fitted on the fixed electrode rod 5 is held between the bottom of the insulating case 1 and the insulating end plate 3 on the side of the fixed electrode rod 5, so that the vacuum shield breaker 6 is attached to the insulating case 1. A nut 13 is attached to the fixed electrode rod 5 protruding from the hole 7 of the insulating case 1.
are screwed together to temporarily fix the vacuum shield breaker 6 to the insulating case 1. Then, the injection port 1 at the bottom of the insulation case 1
Casting liquid rubber is poured from 4 and heated to harden, and the outer surface of the insulating end plate 3 on the movable electrode rod 6 side of the vacuum shield and disconnector 6 is coated from the open end (lower end in FIG. 1) of the insulating case 1. The vacuum switchgear is completed by pouring the cast liquid rubber and heating and hardening it to integrate the insulating case 1 and the vacuum shield and disconnector 6.

In the above-mentioned embodiment, a case was described in which two ring plate-shaped packings 8 having approximately the same outer diameter as the inner diameter of the insulating case 1 were used to form the air layer 9, but the present invention is not limited to this. For example, as in the second embodiment shown in FIG. The air layer 9 may be formed by a ring member 15 having a circumferential groove on its inner peripheral surface, or as in the third embodiment shown in FIG.
The metal cylinder 2 is made of the same material as the packing 8 and has an outer diameter that is approximately the same as the inner diameter of the insulating case 1.
The air layer 9 may be formed by a ring member 15' having a circumferential groove on its inner peripheral surface and fitted around the outer periphery of the ring member 15'.

As described above, in the vacuum switchgear according to the present invention, the outer surface of the vacuum shield and disconnector, which is formed by a metal cylinder and an insulating end plate closing both ends of the vacuum container, is covered with an elastic body made of cast liquid rubber. , it is possible to increase the external flashover value by about 5 to 10 times compared to the conventional one. In addition, since the insulating case and the vacuum shield/disconnector are integrated by an elastic body interposed between them, the mechanical shock when the vacuum shield/disconnector is turned on or disconnected can be quickly attenuated. This makes it possible to prevent peeling of the brazed portion of the vacuum shield or disconnector due to fatigue.

In particular, the vacuum switchgear is a sealed type in which an insulating case and a vacuum shield and disconnector housed concentrically within the insulating case are integrated by an elastic body made of cast liquid rubber interposed between the two. In some cases, the elastic body facing the arc generating part expands locally due to the heat of the arc generated by the contact and separation of the electrodes of the vacuum chamber or disconnector, and this expansion acts as pressure on the vacuum vessel or insulation case. However, there is a risk of peeling of the brazed part of the vacuum shield and disconnector, cracking of the ceramic insulating end plate, or cracking of the insulation case. Since an air layer is provided around the outer circumference of the cylinder, the air is warmed by the arc heat and its pressure is increased, which causes the elastic body interposed between the insulation case and the vacuum shield or disconnector to locally It has the advantage that there is no risk of peeling of the brazed portion of the vacuum shield or disconnector, breakage of the insulating end plate made of ceramic, or breakage of the insulating case.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a first embodiment of a vacuum switchgear according to the present invention, FIG. 2 is a half-cut sectional view of a second embodiment of a vacuum switchgear according to the present invention, and FIG. FIG. 3 is a sectional view of a main part of a third embodiment. 1... Insulating case, 2... Metal tube, 3... Insulating end plate, 4... Electrode, 5... Electrode rod, 6... Vacuum shield disconnector, 8... Packing, 9... Air layer, 10
...Elastic body, 15, 15'...Ring member.

Claims (1)

[Scope of utility model registration request] A vacuum container is formed by closing both ends of a metal tube with insulating end plates in a bottomed cylindrical insulating case, and a pair of electrodes is introduced into the vacuum container so that they can approach and separate from both insulating end plates. A vacuum shield and disconnector, which is provided so as to be movable toward and away from a pair of electrode rods, is housed concentrically with the insulated end plate on the fixed electrode rod side spaced apart from the bottom of the insulating case. The vacuum shield and disconnector are arranged so that an air layer is formed around the outer periphery of the metal cylinder facing the arc generating part in the vacuum shield and disconnector, and the insulated end plate on the movable electrode rod side of the vacuum shield and disconnector is A vacuum opening/closing device characterized in that the two are integrated by an elastic body made of cast liquid rubber which is cast and hardened between the two so as to be coated.