JPS6073200A - Safety device of pressure container - Google Patents

Abstract

PURPOSE:To reduce a discharge noise and improve reliability by providing a temperature actuator having a machanical dead point during the operation due to temperature changes and provided with a needle at its tip coaxially with the center of the discharge diaphragm of a pressure container. CONSTITUTION:A temperature actuator 6 made of a profile memory alloy is provided coaxially with the center of the discharge diaphragm 3 of a discharge diaphragm fitting plate 2, and a needle 7 is provided at its tip. When an abnormal increase of pressure occurs and the temperature actuator 6 in a container is heated by convection, etc. due to the arc heat, the the needle 7 at the tip of the temperature actuator 6 breaks the discharge diaphragm 3, and high-pressure gas is discharged into the atmosphere. In this case, the temperature actuator is formed in a disk shape, thus a mechanical dead point exists during the operation. Accordingly, a snap action is generated when exceeding the dead point, thereby the discharge diaphragm 3 is reliably broken, and the high-pressure gas can be discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a safety device for a pressure vessel using a shape memory alloy as a thermal element.

The pressure volume ER requires mechanical reinforcement against pressure changes due to changes in its filling pressure or physical conditions at the surface. In addition, in abnormal situations such as accidents, a safety device is provided that operates at a pressure of 1 mechanical strength or less.

In particular, circuit breakers and switchgear, which are power switching equipment.

In sealed pressure vessels and conduits such as columnar side closures, SFg gas insulation, and reduced type power distribution stations, when arcing during opening/closing operations or arcing due to insulation breakdown continues for a long time, the pressure inside the vessel will rise abnormally. Therefore, safety equipment is even more necessary.

Conventionally, there is a safety device of this type as shown in FIG. 1 (or Japanese Utility Model Publication No. 49-46603).

In FIG. 1, l is the pressure vessel body, and a four-part discharge membrane 3 is inserted through a sealing O-ring 4.

It is attached to the pressure vessel main body 1 using a plate 2 and screws 5.

A is the high pressure side and B is the atmospheric side.

When the medium sealed in a pressure vessel with a constant volume expands at a temperature of several thousand to several thousand degrees Celsius on the high-pressure side, the pressure rises abnormally.
The membrane radiator 3, which was normally at the position shown by the solid line, is about to move to the position shown by the broken line 3'.

At that time, when the release film 3 becomes linear between the positions of the solid line and the dotted line, stress concentration occurs in the release film 3.

A crack occurs in the release membrane 3, and the medium is instantly released from the high pressure side A to the atmosphere side B.

This structure had the following problems.

■ The thickness of the release membrane 3 is determined by the filling pressure of the medium inside the container, and when the release pressure at which the release membrane 3 operates is set to a desired value, the diameter of the release membrane 3 (D in Figure 1) increases, and the entire container 0 ■ Because the release membrane 3 is large, the medium is released instantly when it is in operation, producing an explosion sound of more than 100 horns.
There was C.

@ The variation in the material of the release j model 3 had a large effect on its operation.

Here, the present invention overcomes the difficulties of conventional devices, and provides a temperature actuator made of a shape memory alloy that expands and contracts in a reciprocal manner due to temperature changes on the side of the filling medium, and uses a needle provided on the temperature actuator to At high temperatures, the release membrane ruptures and the temperature actuator snaps, so its structure is plate-shaped or disk-shaped, and a mechanical dead center is created in the middle of expansion and contraction due to temperature changes. Its purpose is to provide a safety device for containers.

A side sectional view of one embodiment of the present invention is shown in the second frame.

The same reference numerals indicate the same or corresponding parts in all drawings.

The installation of the release membrane 3 is the same as in the conventional figure 1, but
The release membrane 3 may be attached to either the high pressure side A or the atmosphere side B, and in this embodiment, it will be explained by disposing it on the high pressure side A.

Further, the emission film 3 may be planar.

However, in the present invention, the release membrane is attached to the plate 2, and the release membrane 3 is attached to the plate 2.
A temperature actuator 6 made of a shape memory alloy is placed coaxially with the center of the
A needle 7 is set at the tip. The temperature actuator 6 has a disk shape as shown in FIGS. 3(a) and 3(b),
It has a plate shape as shown in FIGS. 4(a) and 4(b).

The shape memory of the temperature actuator is indicated by the dotted line in Figure 2 and the shape memory in Figure 3 (a).
), Fig. 4(a), and are usually installed in the shape of the solid line in Fig. 2, Fig. 3(b), and Fig. 4(ri).

In addition, in FIG. 3<&), (b), a hole 8 is machined in the temporary mounting hole 2 for the temperature actuator.

Note that the blade 17 may be shaped like a knife.

Next, the operation will be explained.

The convergence making assistant 6 is made of a shape memory alloy, and at low temperatures across the martensitic transformation temperature, it freezes as shown in Fig. 2 (Fig. 3 (b), Fig. 4 (b)). , needle 7
The tip is at point M8 in FIG. 2, and a gap is formed between it and the release film 3.

At this M8 point, r, martensitic) ff state initiation temperature.

The temperature actuator is set so that the temperature that the container can withstand over time is below this M8 point.

Next, the arc Q due to the 4-gas breakdown of the insulation n-plane inside the container
υ11] If an accident occurs in which the arc remains connected for a long time due to the inability of the vessel to extinguish the arc, the arc heat will vary depending on the current value, but it will reach a temperature of approximately 4,000 to 10,000 degrees Celsius. (constant) heats and expands, causing an abnormal rise in pressure.

At this time, heat due to radiation and convection due to the arc heat reaches the temperature actuator 6, rapidly warms it, and exceeds the martensitic reverse transformation start temperature AB point, causing the needle 7 provided at the tip of the temperature actuator 6 to release. It begins to extend in the direction of membrane 3.

At this time, due to the structure of the temperature actuator 6, the mechanical dead center of the temperature actuator 6 is at the vertical position shown by the dashed line in FIG. It is stored in the actuator 6.

Then, when a force that can exceed the dead center acts on the temperature actuator 6, -
By the snapping motion, it reaches the point Aj in Fig. 2. The release membrane 3 located in the middle is torn by the needle 7,
The medium in the container is discharged from the high pressure side A to the atmosphere side B.

Thus, according to the present invention, in addition to obtaining a strong recovery stress of about 60 Kg/mm' in irreversible use of shape memory alloys with one or more movements, a strong accelerated stress can be obtained with a snapping action. This provides sufficient stress for the needle 7 to break the release membrane 3.

Moreover, compared to a temperature actuator without snap action, the shape can be made smaller in terms of stress, and furthermore, it can be prevented from malfunctioning like the temperature actuator 6 in FIG. 2 during normal operation.

There is no failure that would break the release membrane 3.

Moreover, due to the strong recovery stress of the temperature actuator 6.

The thickness of the emission film 3 can be increased to 11 times, and at the same time, the diameter of the emission Il!a3 can be made small.

The entire device can be made more compact.

Therefore, the emission time constant of the medium can be arbitrarily determined by the diameter of the emission membrane 3, so that the emission sound can be suppressed to a low level.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of (fi11) of a conventional device, Fig. 2 is a 41111 sectional view of an embodiment of the invention, Fig. 3(a), (
b) is a perspective view of the temperature actuator in this embodiment, FIG. 3(a) is a diagram showing the state at high temperature, FIG. 3(b) is a configuration diagram showing the state at normal low temperature, and FIG. FIG. 4(a) is a perspective view of a temperature actuator according to another embodiment of the present invention, and FIG. 4(a) shows the state when the temperature is high. FIG. l...Pressure vessel body, 2...Release membrane mounting plate, 3
゜31... Release membrane, 4... O-ring for sealing, 5
...screw, 6...temperature actuator, 7...needle, 8...
··hole. Applicant's agent Kiyoshi Inomata Figure 1 Figure 2 F length 1 Figure 3 (Q) (b) Yon 14 Figure (Q) (b)

Claims (1)

[Claims] 1. Made of a shape memory alloy that reversibly expands and contracts in shape with temperature changes that are coaxial with the center of the release membrane of the filling medium in the pressure vessel and sandwiching the martenzite transformation temperature on the side of the filling medium. Equipped with a temperature actuator. The temperature actuator is equipped with a needle that breaks the recording release membrane, and the temperature actuator is formed in the shape of a plate or a disk, and a mechanical dead center is provided in the middle of the expansion and contraction movement due to temperature changes. A safety device for a pressure vessel, characterized in that an actuator performs a snap action.