JPS6312337B2 - - 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 has been made 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 that close both ends of the container 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, one embodiment of the present invention will be described in detail with reference to the drawings.

The figure is a longitudinal sectional view of a vacuum switchgear according to the present invention. In the figure, 1 is an insulating case formed 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, 3 made of ceramic. A vacuum container is formed by using a pair of electrode rods 5, 5, into which a pair of electrodes 4, 4 are introduced from the center of both insulating end plates 3, 3 so as to be able to approach and separate from each other. A vacuum shield breaker 6, which is provided so as to be able to contact and separate (contact and separate), leads out the fixed electrode rod 5 (upper side in the figure) from a hole 7 provided at the center of the bottom of the insulating case 1, and also connects and disconnects the fixed electrode rod 5 to the side of the fixed electrode rod 5. The insulating end plate 3 of the insulating case 1 is housed concentrically with an appropriate distance from the bottom of the insulating case 1.

The outer periphery of the metal cylinder 2 near the middle part of the vacuum shield breaker 6, in other words, 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 is provided with the outer peripheral surface of the vacuum vessel. A band-shaped thermal buffer 8 that is appropriately thinner and wider than the distance between the inner circumferential surface of the insulating case 1 and the inner circumferential surface of the insulating case 1 is disposed. The thermal buffer 8 is
This is to buffer the adverse effects of arc heat on the insulation case 1 and vacuum shield breaker 6, which are integrated through an elastic body as described later, and is made of silicone or crosslinked urethane with excellent heat resistance. It is made of a highly flexible foam sheet with open cells. And insulation case 1
The vacuum shield and disconnector 6 are made of heat-resistant and insulating material such as silicone rubber, polybutadiene rubber, or epoxy rubber, which is cast and hardened between the two so as to cover the insulating end plate 3 on the movable electrode rod 5 side. They are integrated by an elastic body 9 made of cast liquid rubber with excellent properties.

In the figure, 10 is a bellows, 11 is the bottom of the insulating case 1 and the fixed electrode rod 5 of the vacuum shield breaker 6.
It is a ring-shaped packing that is inserted between the side insulating end plate 3 and fitted onto the fixed electrode rod 5, and is made of insulating rubber and has the same degree of elasticity as the elastic body 9. In addition, 12 is the insulation case 1
This is a nut screwed onto the fixed electrode rod 5 protruding from the hole 7 of the electrode.

To manufacture the vacuum switchgear with the above configuration, first, a foam sheet pre-applied with adhesive on one side is wrapped around the outer periphery of the metal tube 2 near the middle of the vacuum shield switch 6 to provide thermal buffering. A body 8 is provided. Next, the packing 11 fitted to 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. The vacuum shield and disconnector 6 is temporarily fixed to the insulating case 1 by screwing a nut 12 onto the fixed electrode rod 5 protruding from the hole 7 of the insulating case 1. Finally, place the insulating case 1 so that its open end (lower in the figure) faces upward, and cover the outer surface of the insulating end plate 3 on the movable electrode rod 5 side of the vacuum shield and disconnector 6 between them. In this way, the cast liquid rubber is poured and heated to harden, and the insulating case 1 and the vacuum shield and disconnector 6 are integrated to complete the vacuum switchgear.

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 that closes 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 a thermal buffer made of a foam sheet is provided around the outer circumference of the cylinder, although the foam itself expands due to the arc heat, the air inside the bubbles inside the foam is compressed and the insulation case and the vacuum are not disconnected. The elastic body interposed between the device and the device will not expand locally, and there is a risk of peeling of the brazed part of the vacuum shield or breaker, breakage of the ceramic insulating end plate, or breakage of the insulating case. It has no effect.

In addition, in the above-mentioned example, a case was described in which a foam sheet made of silicone or cross-linked urethane with excellent heat resistance and having open cells and high flexibility was used as the thermal buffer, but the present invention is not limited to this. For example, one or more hollow rubber rings, or two ring plate-shaped packings fitted into a metal cylinder spaced apart in the axial direction so as to be in sliding contact with the inner surface of an insulating case. an air layer formed by a circumferential groove formed on the inner peripheral surface of a ring member fitted around the outer periphery of a metal tube; A heat dissipating member having a deep groove with a U-shaped cross section that opens outward in the body, or alumina powder filled between the metal tube facing the arc generating part and the insulating case can be used as the thermal buffer. It is possible.

[Brief explanation of the drawing]

The figure is a longitudinal sectional view of a vacuum switchgear according to the present invention. DESCRIPTION OF SYMBOLS 1...Insulating case, 2...Metal tube, 3...Insulating end plate, 4...Electrode, 5...Electrode rod, 6...Vacuum shield, breaker, 8...Thermal buffer, 9...Elasticity body.

Claims (1)

[Claims] 1 A vacuum container is formed in a bottomed cylindrical insulating case by closing both ends of a metal cylinder with insulating end plates, and a pair of electrodes is placed inside the vacuum container so that it can be moved relatively toward and away from both insulating end plates. The vacuum shield and disconnector, which is provided so as to be able to freely approach and separate through the introduced 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, and the vacuum A thermal buffer is provided on the outer periphery of the metal cylinder facing the arc generating part in the shield breaker, and the insulation case and the vacuum shield breaker are covered with an insulated end plate on the movable electrode rod side of the vacuum shield breaker. 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.