JPH07111222A - Safety device - Google Patents

Abstract

PURPOSE:To stabilize the operation and also, drop the internal pressure in a short time, in a safety device which discharges the inner gas by breaking a pressure discharge board when the inner pressure of a sealed container goes up abnormally. CONSTITUTION:A tubular body 3 is attached around the release hole 2 made in a sealed container 1, while a flexible pressure discharge board 4 having a globular section is attached to the inside periphery of the tubular body 3 in such a way that the projection faces to the release hole 2, thus the inside and the outside of the tubular body 3 are partitioned. Furthermore, in the position outside the pressure discharge board 4, a receiving edge 5 for breaking the pressure discharge board 4 at inversion of concave and convex of the pressure discharge board 4 by the rise of the inner pressure of the sealed container 1 is arranged in the position outward of the pressure discharge board 4. The receiving edge 5 is provided with edge parts 12 in the shape bent to cross each other in the direction of progress of cracks at breakdown of the pressure discharge board 4, and they enlarge the opening of the cracks at breakdown of the pressure discharge board 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device which operates when the internal pressure of a hermetically sealed container such as a gas filled condenser rises abnormally.

[0002]

2. Description of the Related Art Conventionally, a protective device is provided so that the power supply is shut off when a gas-filled capacitor housed in a hermetically sealed container causes a dielectric breakdown during use. However, if this protective device does not work and the power is not cut off, gas may be generated inside the container due to dielectric breakdown and the internal pressure may rise, and in the worst case, the capacitor container may be destroyed. A safety device was used to prevent this, but the safety device had a structure as shown in FIGS. 11 and 13.

That is, in the conventional one, as shown in FIG. 11, a cylindrical metal fitting 33 is attached from the outside of the hermetically sealed container 31 around the hole 32 on the bottom surface of the hermetically sealed container 31 of the gas-filled condenser. The pressure relief plate 35 is provided in the hollow portion 33.
Was attached by a metal fitting 34 for pressing the pressure-release plate.
As shown in FIG. 12, the surface of the pressure-release plate 35 has a plurality of scratches radially from the center to form a weak point portion 36, and when the internal pressure of the closed container 31 increases, the pressure-release plate 35 has a weak point. The part 36 was damaged, and gas was released from the damaged part to lower the internal pressure.

Another conventional safety device for a gas-filled type condenser is, as shown in FIG. 13, a metal closed container 41.
A pressure releasing plate 45 having a hemispherical flexibility is arranged outside the container so that its convex portion closes the hole 42 on the bottom surface of the hermetically sealed container 41, and the sharp metal fitting 46 is provided. The pressure relief plate 45 and the sharp metal fitting 46 are arranged so as to face the portion, and the metal fitting 43 and the pressure relief plate pressing metal fitting 4 are provided.
4. The structure was such that the sharp metal fitting mounting plate 47 and the screws 48, 48 were fixed to each other. In this structure, when the internal pressure of the closed container 41 increases, the pressure release plate 45 is
As shown by the dotted line in FIG. 1, the sharp metal fitting 46 hits and breaks, and gas is released from the damaged portion to lower the internal pressure.

[0005]

However, in the former example, since the pressure relief plate is a flat surface, the operating pressure leading to breakage varies, and it is difficult to reduce this variation.
I couldn't get stable operation. Further, it is desirable that the operating pressure of the safety device is as low as possible in order to ensure the safety of the equipment or the like that requires the attachment of the safety device, but the shape of the pressure relief plate in this conventional example cannot be lowered so much.

In the latter example, although the above-mentioned drawbacks can be prevented, when the pressure relief plate is reversed and hits the sharp metal fitting and is damaged, the sharp metal fitting 46 does not pierce the sharp metal fitting 46.
Since the structure itself is closed, the opening area of the pressure release plate 45 due to the damage of the pressure release plate 45 is small, and it is difficult to release a large amount of gas in a short time.

The present invention has been made in order to solve the above-mentioned conventional drawbacks, and an object thereof is to stably operate even when the operating pressure is low and to reduce the internal pressure within a short time. To provide various safety devices.

[0008]

Therefore, in the safety device according to the first aspect of the present invention, the cylindrical body is mounted around the through hole provided in the closed container, while the inner peripheral portion of the cylindrical body has a spherical portion. A flexible pressure relief plate is attached so that its convex surface faces the conduction hole to define the inside and outside of the tubular body. Further, at a position outside the pressure relief plate, the internal pressure of the closed container increases due to In a safety device in which a receiving blade is arranged to damage the pressure releasing plate when the pressure releasing plate is turned upside down, in the safety device, the receiving blade is a blade curved so as to intersect the crack progressing direction when the pressure releasing plate is broken. It is characterized by having a part.

According to a second aspect of the safety device of the present invention, a pair of step portions are provided around the inner peripheral portion of the cylindrical body, a pressure release plate is provided at one step portion, and a blade is provided at the other step portion. It is characterized in that each is inserted.

Further, in the safety device according to claim 3, sliding contact portions are formed at both ends of the receiving blade, and the receiving blade elastically presses the step portion and the sliding contact portion against the step peripheral wall surface. It is characterized in that it is fitted in a state of being in contact.

The safety device according to a fourth aspect is characterized in that the closed container accommodates electric equipment such as a capacitor element.

[0012]

In the safety device according to the first aspect, when the internal pressure of the closed container reaches a certain level, this pressure is transmitted to the pressure relief plate through the conduction hole, and the pressure relief plate is inverted to cause the pressure relief plate of the pressure receiving plate to move. Damage begins. Since the receiving blade has the curved blade portion so as to intersect with the crack advancing direction, the crack generated by the reversal of the pressure release plate is torn by the blade portion forming the bent portion, and the crack is spread. In this way, the opening area of the pressure relief plate becomes large due to the damage, so that a large amount of gas can be discharged in a short time, and the internal pressure can be reduced in a short time.

According to another aspect of the safety device of the present invention, the pressure-release plate and the receiving blade are simply fitted into the stepped portion provided inside the same cylindrical body, and the pressure-release plate is not required to be finely adjusted. It can be installed accurately with the blade.

Further, according to the safety device of the third aspect, the elasticity of the receiving blade can be used to fix the receiving blade, so that the safety device can be easily assembled.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the safety device of the present invention will be described in detail with reference to the drawings. 1 is an exploded perspective view of a safety device according to an embodiment of the present invention, FIG. 2 is a sectional view of the same embodiment, FIG. 3 is a plan view of a blade used in the same embodiment, and FIG. 4 is a front view of the blade. FIG. 5 and FIG. 5 are front views of the gas filled capacitor to which the safety device according to this embodiment is attached.

In FIG. 5, 1 is a closed container, 14 is a capacitor element, 15 is an insulating gas sealed in the capacitor,
Reference numeral 16 is an external lead terminal, 17 is a mounting leg, and 18 is a safety device according to this embodiment.

Next, details of the safety device 18 will be described. In FIG. 1 and FIG. 2, a safety device 18 includes a through hole 2 formed in a part of a closed container 1 in which a capacitor element is housed, a tubular body 3 attached to the closed container 1, and a tubular body 3 It is composed of a pressure release plate 4 mounted inside the body 3 and a receiving blade 5.

The pressure release plate 4, the receiving blade 5 and the tubular body 3 have the following shapes. First, the pressure release plate 4 is made of a flexible metal having a spherical portion, and has a brim portion 7 around it. The receiving blade 5 is formed by molding a metal plate, and is shown in FIGS.
As shown in FIG. 2, two sides sandwiching the apex of the triangular plate are sharpened blade portions 12, 12, which are curved in an S shape along the bottom side. Therefore, the receiving blade 5 is S-shaped (FIG. 3) when viewed from above, and triangular (FIG. 4) when viewed from the side. Further, the tubular body 3 is a cylindrical body having an integrally formed opening, and has a flange portion 11 on the outer periphery of the opening. Further, inside the cylindrical body 3, there are provided an upper step portion 8, a middle step portion 9, and a lower step portion 10 which are concentric from the opening toward the bottom surface and whose diameter becomes smaller toward the bottom surface.

The pressure release plate 4, the receiving blade 5 and the tubular body 3 are assembled as follows. First, the receiving blade 5 is fitted into the lower step portion 10 of the tubular body 3 so that the blade portions 12, 12 thereof face upward, and due to the elasticity of the receiving blade 5, the S-shaped both end portions 5a of the receiving blade 5, 5a is pressed and fixed to the side surface of the lower step portion 10. In addition, as shown in FIG.
Since a is slightly overhanging inward, the receiving blade 5 fitted in the lower step portion 10 is unlikely to come off. The pressure relief plate 4 is fitted into the upper step portion 8 of the tubular body 3 such that the convex surface thereof faces the upper opening of the tubular body 3, and the collar portion 7 of the pressure relief plate is brought into contact with the upper step portion 8 of the pressure relief plate 4.
It is attached to the bottom surface of the and fixed by soldering. As a result, the inner space of the tubular body 3 is partitioned into two spaces, a space in contact with the convex surface of the pressure-release plate 4 and a space in contact with the concave surface, while maintaining airtightness. The middle section 9 is provided to secure a space required for the pressure relief plate 4 to be reversed, as shown by the dotted line in FIG.

The tubular body 3 is fixed by welding so that the upper opening of the tubular body 3 covers the conduction hole 2 of the closed container 1 and the flange portion 11 is closely attached to the outer surface of the closed container 1 and welded. Has been done.

In the gas-filled type capacitor having the safety device constructed as described above, when the protective device does not work and the power is not cut off even though the dielectric breakdown occurs during use, the gas due to the dielectric breakdown occurs. Occurs in the closed container 1 and the internal pressure rises. This increased internal pressure is transmitted to the pressure relief plate 4 through the conduction hole 2, the pressure relief plate 4 is reversed as shown by the dotted line in FIG.
As a result of being damaged, the gas is released from the damaged part, and the gas is discharged to the outside through the lower discharge hole 6 of the cylindrical body 3, whereby the internal pressure in the closed container 1 is lowered.

The operation of the safety device in this case will be described in detail. When the internal pressure of the closed container 1 reaches a certain level, the pressure relief plate 4 is started to be turned over. The apex of the blade portion 12 of 5 breaks through the pressure relief plate 4, and the damage of the pressure relief plate 4 is started. Since the shape of the receiving blade 5 is triangular (FIG. 4) when viewed from the side and S-shaped (FIG. 3) when viewed from above as described above, the apex of the blade portion 12 of the receiving blade 5 is the pressure release plate 4. Since the crack generated at the time of breaking through is torn into an S shape as the pressure relief plate 4 is reversed, the crack is spread. In other words, when the shape of the receiving blade is a simple needle or a flat plate, the receiving blade itself will close the cracks that have been pierced after the pressure releasing plate is pierced. The opening area of the generated crack becomes large. Therefore, a large amount of gas can be released in a short time, and the internal pressure of the closed container 1 can be lowered in a short time.

Further, in this embodiment, the pressure relief plate 4 does not have the scratched weak points 36 as in the conventional pressure relief plate 35 shown in FIG. Differences in scratch depth do not lead to differences in operating pressure. Further, the tubular body 3 to which the pressure release plate 4 and the receiving blade 5 in this embodiment are attached is integrally molded as described above, and the pressure release plate 4 and the receiving blade 5 are fitted into the groove inside the tubular body 3. Since this is sufficient, it is possible to reduce the positioning error between the pressure relief plate 4 and the receiving blade 5 as compared with the conventional example shown in FIG. 13, and to stabilize the operating pressure. This makes it possible to subdivide and set the operating pressure from low pressure to high pressure when various kinds of safety devices having different operating pressures are manufactured by changing the size and the original size of the pressure relief plate 4.

FIG. 6 shows the result of a concrete trial production based on the above-mentioned embodiment. Pressure release plate 4 used in this prototype
Is made of copper and has a diameter of 40 mm and a thickness of 0.15 mm. From FIG. 6, the operating pressure is 3 kgf / cm ² ± 0.3 kgf /
It is cm ₂ , and it can be seen that the operating pressure is stable.

In the above embodiment, the shape of the receiving blade 5 is an S-shaped bent shape as shown in FIG. 3 when viewed from above, but the shape is not limited to this and a Z-shaped shape. It is also possible to bend it into a W shape or the like. Further, when the receiving blade 5 in the above embodiment is viewed from the front and has a triangular shape as shown in FIG. 4, it is not limited to this.

7 to 10 show an embodiment in which the safety device according to this embodiment is attached to an oil-filled capacitor. 7 to 1
In 0, 21 is a closed container, 22 is an external lead terminal, 2
3 is a safety device similar to the above. For oil-filled capacitors, if the capacitor suffers a dielectric breakdown, the power is cut off as in the case of the gas filled capacitor.However, if the power is not shut off, the gas generated by the dielectric breakdown will increase the internal pressure. If the temperature rises and, in the worst case, the condenser container is destroyed, there is a possibility of developing a major accident such as a fire caused by oil spray. A safety device is installed to prevent this, but if this safety device is attached to the bottom of the capacitor, the oil in the capacitor will flow down to the floor where the capacitor is installed when the safety device is activated, and secondary damage will occur. May cause. Therefore, when the safety device according to the present invention is attached to an oil-filled condenser, the safety device prevents the oil from flowing down from the discharge hole of the safety device during operation of the safety device, as shown in FIGS. It is preferable to mount the capacitor in a position that will be on the top when it is installed.

In the above embodiment, the safety device is attached to the gas-filled or oil-filled capacitor, but the invention is not limited to this, and other electric devices using a hermetically sealed container having a risk of internal pressure rise. It can be attached to equipment and other than similar electric equipment.

[0028]

As described above, in the safety device according to the first aspect, since the effect of the pressure relief plate damage caused by the shape of the receiving blade is great, the internal pressure is reduced in a short time, so that the performance of the safety device is improved. I can contribute.

According to the safety device of the second aspect, the pressure-release plate and the receiving blade are simply fitted into the stepped portion provided inside the same cylindrical body, and the pressure-release plate is not required to be finely adjusted. Since the blade and the blade can be accurately attached, the assembling work can be facilitated and the operation can be stabilized.

Further, according to the safety device of the third aspect, the elasticity of the receiving blade can be used to fix the receiving blade, so that the safety device can be easily assembled.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a safety device according to an embodiment of the present invention.

FIG. 2 is a sectional view of the same embodiment.

FIG. 3 is a plan view of a receiving blade used in the embodiment.

FIG. 4 is a front view of the receiving blade.

FIG. 5 is a front view of a gas filled capacitor according to an embodiment of the present invention.

FIG. 6 is a graph showing a result of trial manufacture according to the same example.

FIG. 7 is an external view of an oil-filled capacitor according to another embodiment of the present invention.

FIG. 8 is an external view of an oil-filled capacitor according to another embodiment of the present invention.

FIG. 9 is an external view of an oil-filled capacitor according to another embodiment of the present invention.

FIG. 10 is an external view of an oil-filled capacitor according to another embodiment of the present invention.

FIG. 11 is a sectional view of a conventional safety device.

FIG. 12 is a top view of a pressure release plate used in the conventional example.

FIG. 13 is a cross-sectional view of another conventional safety device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Airtight container 2 Conduction hole 3 Cylindrical body 4 Pressure release plate 5 Receiving blade 6 Discharge hole 7 Collar part of pressure release plate 8 Upper step 10 Lower step 12 Blade part 13 Bottom

Claims (4)

[Claims] 1. A cylindrical body is mounted around a conducting hole provided in a hermetically sealed container, while a flexible pressure-release plate having a spherical portion is provided on the inner peripheral portion of the cylindrical body, the convex surface of which is the conducting hole. It is installed so as to face the hole to partition the inside and outside of the cylindrical body, and at a position outside the pressure relief plate, the pressure relief plate is damaged when the unevenness of the pressure relief plate is reversed due to an increase in the internal pressure of the closed container. In the safety device in which the receiving blade is arranged to perform, the receiving blade has a curved blade portion that intersects with a crack advancing direction when the pressure relief plate is broken. 2. A pair of step portions are provided around the inner peripheral portion of the cylindrical body, a pressure release plate is fitted in one step portion, and a receiving blade is fitted in the other step portion. Claim 1 characterized by the above-mentioned.
Safety device. 3. A sliding contact portion is formed at both ends of the receiving blade, and the receiving blade is in a state in which the sliding contact portion is elastically pressed and brought into contact with the step peripheral wall surface with respect to the step portion. The safety device according to claim 2, wherein the safety device is fitted. 4. The safety device according to claim 1, wherein the closed container houses an electric device such as a capacitor element.