JPS60155001A - Dashpot structure for gas shut-off valve - Google Patents

Abstract

PURPOSE:To relax stress generated in a cylinder member in a dashpot for a gas shut-off valve, by allowing fluid to enter into and discharge from the dashpot through a clearance between the inner surface of the cylinder and the fitting part of a piston. CONSTITUTION:The flow of fluid for controlling the operation of a shut-off unit having a movable contat which is connected through link to a piston 1, is carried out through a clearance between the inner surface of a cylinder and the fitting part of a piston 1. Further, in the case of a cylinder in which no suction and discharge fluid holes are formed, there is no stress concentration generated by high pressure fluid in the cylinder, other than nominal stress which is inversely proportional to the wall-thickness of the cylinder so that it is possible to aim at reducing stress generated in the cylinder. With this arrangement, stress generated in the cylinder member may be reduced, thereby apparatus having a high-degree of reliability may be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a stress relaxation structure for a gas circuit breaker and a dashpot cylinder of a gas insulated switchgear.

[Background of the invention]

The dashpot structure of a conventional gas circuit breaker is shown in FIG. The piston 1 is connected to a movable contact of the coupler by a link, and the piston 1 moves leftward and rightward as the movable contact is tripped and closed. When the movable contact performs a tripping operation, the piston moves to the left, and the fluid in the oil chamber 7 flows out from the fluid suction and discharge hole 8 to the oil chamber 6 in the tank.

At the same time, the fluid in the tank oil chamber 6 flows into the oil chamber 5. When the movable contact performs closing operation, piston 1
moves to the right, and the fluid is sucked and discharged in the opposite manner to that described above. When the piston 1 operates at high speed and the fluid flows out through the suction/discharge hole 8, the amount of fluid discharged is limited by the area of the discharge hole. That is, the speed of the movable contactor is controlled by the viscous resistance of the fluid. If the piston 1 moves to the left, the oil chamber 7. When moving to the right, the fluid pressure in the oil chamber 5 becomes several hundred atmospheres. Therefore, stress is generated in the cylinder 3 due to internal pressure. The stress distribution at this time is shown in the third direction and in FIG. When there is no fluid suction and discharge hole around the cylinder 3, when the stress when the cylinder cylinder receives internal pressure is σ,
The stress distribution when there is a discharge hole is as shown in FIGS. 3 and 4, and the maximum stress σmmK occurs at the edge of the discharge hole and becomes σ□Aki3σ.

In other words, when there is a discharge hole, approximately three times as much stress is generated as compared to the stress generated when there is no discharge hole.

In recent years, as the demand for electricity has increased, there has been a strong demand for highly reliable substation equipment, which has a long lifespan of several decades, and moreover, it is difficult to break or break the dashpot that brakes the operating speed of the circuit breaker. This significantly reduces the performance of the dashpot and even affects its life, so there is a strong desire to improve the strength of the dashpot.

[Purpose of the invention]

The purpose of the present invention is to provide a gap between the dashpot cylinder 3 and the piston 1 for sucking and discharging fluid in order to improve the strength of the dashpot of a gas circuit breaker, thereby alleviating the stress generated in the cylinder 3 when the circuit breaker operates. Our goal is to provide highly reliable equipment that prevents cylinder damage and destruction.

[Embodiments of the invention]

An embodiment of the invention is shown in FIGS. 5 and 6.

The piston 1 is connected to a movable contact of a circuit breaker by a link. With the tripping and closing operations of the movable contact, the piston 1 moves leftward and rightward.

The movement of fluid for controlling the operation of the circuit breaker is performed in the gap between the inner surface of the cylinder and the fitting of the piston 1.

That is, when the piston 1 moves to the left, the fluid in the oil chamber 7 passes between the inner surface of the cylinder and the piston 1 and moves to the oil chamber 5. At this time, the outflow area from the oil chamber 7 to the hydraulic pressure 5 is controlled by the area of the gap between the inner surface of the cylinder and the piston fitting portion. When the piston 1 moves to the right, the fluid moves from the oil chamber 5 to the oil chamber 7.

When the piston 1 moves leftward and rightward, causing a movement of fluid within the cylinder 0, first, when moving leftward, the pressure in the oil chamber 7 becomes high. Also, if it moves to the right, oil chamber 5
becomes high pressure. Here, since the speed of the piston 1 is controlled in the same way as in the conventional method shown in FIG. 1, the internal pressure accompanying the movement of fluid inside the cylinder is the same as in the conventional method. Therefore, in the case of a cylinder not shown in Fig. 5, i.e., a cylinder without a hole for fluid suction, there is no stress concentration caused by high-pressure fluid in the cylinder, and the nominal stress is inversely proportional to the wall thickness of the cylinder cylinder. Only stress. That is, it becomes possible to reduce the stress generated in the cylinder.

The single rond system of this embodiment is effective because the force in the bending direction is relatively small when the circuit breaker contact and the cylinder 1 are arranged on the same axis and the cylinder moves leftward and rightward.

When the movable contact and the piston 1 are not arranged on the same axis and force is transmitted in a right angle direction via a sector link or the like, a force acts on the piston 1 in the bending direction. As shown in Figure 5,
If the piston is a single rod structure, piston 1 and cylinder 1
Because there is a gap on the inner surface of 0 for fluid movement,
The piston 1 is supported only by the rod part. Therefore, as an application example for alleviating stress caused by bending, the seventh
A piston structure having both ronds as shown in the figure and FIG. 8 is made.

The movement of fluid within cylinder 13 as piston 11 moves to the left and right is similar to that of a single rod piston configuration. In addition, in the figure, 2 and 12 are tanks, and 14 is a lid.

〔Effect of the invention〕

According to the present invention, in the dashpot structure of a power circuit breaker, it is possible to reduce the stress generated in one member of the cylinder, and it is possible to provide a highly reliable device.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of the main parts of a conventional dashpot cylinder, Figures 3 and 4 are stress distribution diagrams of the conventional dashpot cylinder, and Figures 5 to 8 are cross-sectional views of the main parts of the present invention. It is a diagram.

Claims (1)

[Claims] 1. In a dashpot consisting of a piston, a cylinder, and an oil tank that control the operating speed of a gas circuit breaker or gas insulated switchgear. Means is provided for completely relieving stress generated in the cylinder member during braking of tripping and closing operations of the gas circuit breaker by discharging and suctioning fluid from a gap between a fitting portion between the inner surface of the cylinder and the piston. This is a dashpot structure for gas circuit breakers.