JPH06187881A - Puffer type gas-blast circuit breaker - Google Patents

Abstract

PURPOSE:To reduce the force required for controlling a drive rod so as to miniaturize a driving unit by forming between the inner and outer peripheral surfaces of the inside wall of a puffer chamber a clearance which broadens toward a blast hole along the direction of the axis of the puffer chamber, and preventing gas pressure within the puffer chamber from building up more than needed. CONSTITUTION:A puffer chamber 6 is drilled at its inside on the side of a puffer cylinder 5 toward a blast hole along the direction of the axis thereof. When a fixed piston 8 comes to the position of a dotted line 80 a clearance 21 forms between the puffer cylinder 5 and a slide ring 17. A plurality of cylinder guides each projecting from the inside wall of the cylinder 5 into pulse form are provided in the clearance 21. During breaking action gas escapes downward via the clearance 21, so the excess buildup of gas pressure within the puffer chamber 6 is prevented. A piston guide 21A is so designed that when the fixed piston 8 comes to the broadened portion of the chamber 6 the slide ring 17 slides against the guide 21A. The piston 8 is therefore prevented from oscillating radially.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a puffer type gas circuit breaker used as a large capacity power circuit breaker.

[0002]

2. Description of the Related Art A puffer type gas circuit breaker compresses arc extinguishing gas and blows the compressed gas onto a gap of a breaking portion to extinguish the generated arc and shut off a large current. . As a gas for extinguishing an arc, SF ₆ gas is very excellent and is used even for an ultra-high pressure, large capacity circuit breaker. Figure 5
FIG. 4 is a cross-sectional view showing a main part configuration of a conventional puffer type gas circuit breaker. A fixed contact 3 supported via an insulator 2 in a cylindrical metal container 1 filled with SF ₆ gas of several atmospheres as an arc extinguishing gas, and a movable contact 4 capable of contacting and separating from the fixed contact 3.
And are arranged to form a separation gap portion 9. A first insulating nozzle 10A and a second insulating nozzle 10B are arranged so as to surround the movable contactor 4, and support the insulating nozzle and the movable contactor 4 and drive rod at the center.
A puffer cylinder 5 with 12 is arranged. The puffer cylinder 5 includes a puffer chamber 6 formed by inserting a fixed piston 8 fixed via an insulating porcelain tube 7. An insulating rod 13 for driving the movable contactor 4 is connected to the drive rod 12, and a hollow portion of the drive rod 12 forms an exhaust passage 12A for connecting the opening gap 9 and the free space 11 to each other. .

FIG. 6 is an enlarged cross-sectional view of one side of the fixed piston 8 shown in FIG. There is a central shaft (not shown) on the left side of FIG. 6, and the fixed piston 8 is provided with orbital grooves 8A and 8B. The slide rings 17 and 18 are fitted in the circumferential grooves 8A and 8B, respectively, and slide with the puffer cylinder 5 and the drive rod 12 that form the inner wall surface of the puffer chamber 6. The slide rings 17 and 18 prevent the gas in the puffer chamber 6 from leaking downward.

FIG. 7 is a plan view of only the slide ring of FIG. 6 viewed from the Q direction. The slide rings 17 and 18 are provided with slits 19 at one place on the circumference. This slit 19 is for fitting it into the circumferential groove of the fixed piston by slightly expanding it. Returning to FIG.
Insulating rod from drive not shown when current is cut off
When the driving force in the X direction is transmitted via 13, the movable contactor 4, the first insulating nozzle 10A, the second insulating nozzle 10B, the drive rod 12, and the puffer cylinder 5 which are the movable portion integrated with each other are connected. Moves in the X direction. In the state where the fixed contactor 3 does not escape from the throat portion 10 of the first insulating nozzle 10A, as shown in FIG. 5, the gas compressed by the fixed piston 8 in the puffer chamber 6 blows out from the blowing hole 5A. This blowing gas becomes a gas flow 14A, and the first insulating nozzle 10A
And flows through the gap between the second insulating nozzle 10B and the arc 15 generated in the open gap portion 9 to cool it. The gas heated by the arc 15 is discharged into the free space 11 through the exhaust passage 12A as gas flows 14B and 14C. As the breaking current increases, the arc 15 increases and tries to close the inlet of the exhaust passage 12A, so the gas flow 14A from the puffer chamber 6
Tends to flow less easily. Therefore, the gas pressure in the puffer chamber 6 increases as the breaking current increases.

Such an arc extinguishing method, that is, a method of extinguishing the arc by closing the inlet side of the exhaust passage 12A with the arc 15 at the initial stage of the current interruption to increase the pressure increase in the puffer chamber 6 is used. It is called a puffer type, which is used as a large-current breaker because the fixed contactor 3 can take a large amount of gas to blow to the arc 15 when the fixed contactor 3 escapes from the throat portion 10 of the first insulating nozzle 10A. Has been done.

FIG. 8 is a sectional view showing the structure of the essential part of a conventional puffer type gas circuit breaker. At the outlet of the blowing hole 5A of the puffer chamber 6, a check valve 20 is provided to allow only the gas flow 14D in the direction from the puffer chamber 6 to the separation gap portion 9 to pass. Other configurations are the same as those in FIG. 5, and the configuration of the fixed piston 8 week side is also the same as in FIGS. 6 and 7. The check valve 20 of FIG. 8 is for preventing the gas expanded by the arc 15 from flowing back to the puffer chamber 6 side. Therefore, in the device of FIG. 8, the pressure increase in the puffer chamber 6 in the former is smaller than that in FIG. 5 because there is no backflow of the expansion gas. Therefore, there is an advantage that the drive device for compressing the gas in the puffer chamber 6 can be made smaller.

[0007]

However, the conventional device as described above has a problem that the gas pressure in the puffer chamber increases more than necessary during operation. The space in the puffer chamber is reduced as the drive rod moves. Some of the gas is discharged from the spray hole to the opening gap, but the outlet of the spray hole is filled with the expansion gas, so the pressure in the puffer chamber rises faster. Therefore, the gas pressure in the puffer chamber increases more than necessary. Since the check valve 20 is provided in the device of FIG.
The amount of increase in gas pressure is reduced to some extent, but the amount of increase in gas pressure due to only the drive rod 12 of the puffer chamber 6 is not reduced.
For this reason, if the drive device is made too small, a retrograde phenomenon in which the movable contact is pushed back occurs and it becomes impossible to shut off.

An object of the present invention is to loosen some gas from the sliding portion of the slide ring so as to alleviate the force required for operating the drive rod and to downsize the drive device.
In the puffer type gas circuit breaker as described above, it is an object to obtain a configuration in which the gas pressure in the puffer chamber is prevented from rising more than necessary during its operation, particularly a puffer chamber configuration.

[0009]

In order to achieve the above object, according to the present invention, a fixed contact and a movable contact capable of contacting and separating from the fixed contact are provided in a metal container filled with an arc-extinguishing gas.
A puffer cylinder that interlocks with the movable contactor, a fixed piston that forms a puffer chamber in the puffer cylinder, and a gas that surrounds the movable contactor and is compressed in the puffer chamber is provided on the side opposite to the fixed piston of the puffer cylinder. In a housing in which an insulating nozzle leading from the spray hole to the open gap between the fixed contact and the movable contact is housed, the gap between the inner peripheral surface and the outer peripheral surface of the puffer chamber inner wall starts from the middle in the axial direction. It shall be formed wide toward the spray hole side.

In such a structure, it is assumed that a plurality of piston guides protruding in a toothed manner are provided on the inner wall of the puffer chamber in a wide portion.

[0011]

According to the construction of the present invention, the gap between the inner peripheral surface and the outer peripheral surface of the inner wall of the puffer chamber is widened from the middle in the axial direction to the spray hole side. As a result, a gap is created between the slide ring and the inner wall of the puffer during the shutoff operation, and the gas escapes through this gap. Therefore, it is possible to prevent the gas pressure in the puffer chamber from rising excessively.

In such a structure, a plurality of piston guides protruding in a toothed shape are provided on the inner wall of the puffer chamber in a wide portion. This can prevent the fixed piston from swinging laterally in the radial direction.

[0013]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is an enlarged sectional view of essential parts of a puffer type gas circuit breaker according to an embodiment of the present invention. The inner wall of the puffer chamber 6 on the puffer cylinder 5 side is cut away from the middle in the axial direction toward the spray hole (upper side in FIG. 1) side to the outside (left side in FIG. 1). A gap 21 is formed between the puffer cylinder 5 and the slide ring 17 when the fixed piston 8 reaches the position of the dotted line 80. The gap 21 is formed so that the inner wall of the puffer cylinder 5 can be formed within the axial length H.

FIG. 2 is a view on arrow A of FIG. The gap 21 projects from the inner wall of the puffer cylinder 5 in the shape of a tooth 4
Individual cylinder guides 21 are provided. Other configurations of FIGS. 1 and 2 are the same as those of the conventional apparatus shown in FIGS. The same parts are designated by the same reference numerals, and detailed description thereof is omitted. In FIG. 1, since the gas escapes downward through the gap 21 during the shutoff operation, the gas pressure in the puffer chamber 6 does not rise excessively.
In the piston guide 21A of FIG. 2, the slide ring 17 slides on the piston guide 21A when the fixed piston 8 reaches the widened part of the puffer chamber 6.
This can prevent the fixed piston 8 from laterally swinging in the radial direction.

FIG. 3 is an enlarged cross-sectional view of essential parts of a puffer type gas circuit breaker according to a different embodiment of the present invention. The only difference from FIG. 1 is that the gap 22 is formed on the drive rod 12 side. 4 is a view from the arrow B of FIG. 3, and four piston guides 22A are provided on the drive rod 12 so as to project therefrom.
In FIG. 3 as well, as in FIG. 1, the gas escapes downward through the gap 21 from the middle of the shutoff operation, so that the puffer chamber 6
The gas pressure inside does not rise excessively. Also, since the piston guide 22A slides on the slide ring 18,
The fixed piston 8 does not swing laterally in the radial direction.

Although the gap is formed on either the inner peripheral surface or the outer peripheral surface of the puffer chamber 6 in the embodiment of FIGS. 1 and 2, the gap is formed on both inner wall surfaces of the puffer chamber 6. Good. The number of piston guides should be at least 3
The number of the fixed pistons 8 may be one, and the lateral runout of the fixed piston 8 can be suppressed by equally arranging them on the circumference. Furthermore, FIG. 1 and FIG.
The configuration described in (1) may be applied to the device in which the check valve 20 in FIG. 8 is arranged, and the same operation as that described in the device in FIG. 5 works.

[0017]

As described above, according to the present invention, the gap between the inner peripheral surface and the outer peripheral surface of the puffer chamber inner wall is widened from the middle of the axial direction to the spray hole side. This prevents the gas pressure in the puffer chamber from rising more than necessary, so that the force required to operate the drive rod is alleviated and the drive device can be made compact.

Further, in such a structure, a plurality of piston guides protruding in a toothed shape are provided on the inner wall of the puffer chamber in a wide portion. As a result, the fixed piston can be prevented from swinging laterally in the radial direction, and abnormal vibration of the entire apparatus can be eliminated.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part showing the configuration of a puffer type gas circuit breaker according to an embodiment of the present invention.

FIG. 2 is a view on arrow A in FIG.

FIG. 3 is an enlarged sectional view of an essential part showing the structure of a puffer type gas circuit breaker of a different invention.

FIG. 4 is a view on arrow B of FIG.

FIG. 5 is a cross-sectional view of essential parts showing the configuration of a conventional puffer type gas circuit breaker.

6 is an enlarged cross-sectional view of one side of the fixed piston shown in FIG.

7 is a plan view of the slide ring of FIG.

FIG. 8 is a cross-sectional view of main parts showing the configuration of a conventional different puffer type gas circuit breaker.

[Explanation of symbols]

5: Puffer cylinder, 5A: Spray hole, 6: Puffer chamber, 8: Fixed piston, 8A, 8B: Circular groove, 17, 1
8: slide ring, 21, 22: gap, 19: slit, 21A, 22A: piston guide, 12: drive rod

Claims (2)

[Claims] 1. A metal container filled with an arc-extinguishing gas, a fixed contact, a movable contact capable of coming into contact with and separating from the fixed contact, a puffer cylinder interlocking with the movable contact, and a puffer in the puffer cylinder. The fixed piston that forms the chamber and the movable contactor that surrounds the movable contactor and separates the gas compressed in the puffer chamber from the blowing hole provided on the side of the puffer cylinder opposite to the fixed piston between the fixed contactor and the movable contactor. A puffer shape in which an insulating nozzle leading to the gap is housed, and a gap between the inner peripheral surface and the outer peripheral surface of the puffer chamber inner wall is formed to be wide from the middle in the axial direction to the spray hole side. Gas circuit breaker. 2. The puffer-type gas circuit breaker according to claim 1, wherein a plurality of piston guides protruding in a toothed shape are provided on a puffer chamber inner wall of a wide portion.