JPH029483Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The invention is used in the field of safety equipment. More specifically, it is used in the field of safety devices for gas-filled switches. The present invention relates to a pressure relief mechanism that releases the internal pressure to the outside when an abnormal increase in internal pressure occurs in a gas-filled switch.

[Prior art and its problems]

For example, in a gas switch, a mechanism shown in FIG. 5 is known as a pressure relief mechanism that releases high-pressure gas from a casing when an explosion occurs due to a short circuit or the like inside the switch. This mechanism has a thin pressure relief plate 20 with a spherical bulging surface, and when the pressure inside the casing 21 becomes abnormally high, the pressure relief plate 20 is reversed and released by a cutter 22 installed at the inverted position. The pressure plate 20 was destroyed and the internal pressure was released. However, this pressure relief mechanism requires management such as (a) forming a spherical bulging surface on the pressure relief plate, keeping the thickness of the pressure relief plate within a certain range, and keeping the material of the pressure relief plate constant; (b) Even if a metal plate is thin, a considerable amount of pressure is required to break it, so in order to keep the operating value low, a thin metal plate must be used. If a thin metal plate is used, it will corrode due to the outside air over time, and if a hole is drilled in the pressure relief plate, airtightness will no longer be maintained, which may lead to an accident. In order to do so, it is necessary to strictly control the material and dimensions of the pressure relief plate, which raises the cost of the pressure relief plate.

[Purpose of invention]

Therefore, the present invention is designed to operate completely in the event of an abnormality without paying much attention to the material and dimensions of the pressure relief plate, and to allow the use of a thick pressure relief plate to prevent accidents caused by corrosion. purpose.

[Structure of the idea]

The structure of the present invention taken to achieve the above object is as follows. That is, in the present invention, a part of the wall surface of the casing is recessed to form a fitting part, and the fitting part is provided with an inner circumferential wall that is bent from the wall surface of the casing toward the inside of the casing. A through hole for degassing is formed in the area surrounded by the inner peripheral wall, and the pressure relief plate fixed to the casing has a fitting convex body forming an outer peripheral wall that fits into the inner peripheral wall. In this case, a stepped portion is formed and a mounting flange is continuously formed through the stepped portion, and a sealing gasket is interposed between the inner peripheral wall and the stepped portion, and the pressure relief plate is inserted into the sealing gasket in the direction in which the pressure relief plate is inserted. The pressure relief plate is fitted into the fitting part with a lateral pressing force being applied to the pressure relief plate, and the fixing points of the mounting flange are arranged unevenly to prevent the plate from deforming and becoming a pressure relief port when the internal pressure increases. This is a pressure relief mechanism with a section. Under normal conditions, the pressure relief plate closes the through hole to prevent the gas sealed inside from leaking out, but when an abnormal situation occurs and the internal pressure rises above a certain level, the vulnerable part may close. It deforms to release internal pressure and prevent the casing from being destroyed.

【Example】

The present invention will be explained in more detail based on embodiments shown in the drawings. In FIGS. 1 to 4, a bottom wall 11 of a casing 1 of a switch is partially recessed to form a fitting portion 1a. The fitting part 1a is provided with an inner circumferential wall 3 that is bent from the bottom wall 11 toward the inside of the casing 1, and a through hole 2 for gas venting that penetrates inside and outside is provided at a location surrounded by the inner circumferential wall 3. is formed. In this embodiment, the inner circumferential wall 3 is inclined slightly inward, but it may be bent at right angles to the bottom wall 11. Further, the tip 31 of the inner peripheral wall 3 is connected to the bottom wall 11.
It is bent parallel to. Three stud bolts 5, 5a, and 5b for attaching the pressure relief plate 7 are disposed unevenly on the bottom wall 11 in the vicinity of the periphery of the insertion portion 1a. As described later, these stud bolts 5a,
By changing the position of 5b, it is possible to arbitrarily set the operating pressure of the pressure relief mechanism without changing the thickness of the pressure relief plate 7 or other mechanisms. For example, if the stud bolts 5a and 5b are placed on line A shown in Fig. 2, the operating value of the pressure relief mechanism will be lower than the operating value in the illustrated state, and if the stud bolts 5a and 5b are placed on line B, the pressure relief mechanism will operate. The value goes up. Reference numeral 7 denotes a pressure relief plate having an outer circumferential wall 4 and a mounting flange 6 connected to the outer circumferential wall 4. Outer wall 4
A stepped portion 41 is formed around the entire circumference.
A sealing O-ring 8 is fitted into this stepped portion 41, and the O-ring 8 is fitted into the fitting portion 1a with a pressing force applied in a direction transverse to the fitting direction of the pressure release plate 7. The mounting flange 6 has stud bolts 5,
Attachment holes are provided at locations corresponding to 5a and 5b, and the pressure relief plate 7 is fixed with nuts 9. Therefore, the attachment points of the pressure relief plate 7 to the casing 1 are not evenly arranged, and a fragile portion 10 is provided which deforms when the internal pressure increases and becomes a pressure relief port. Note that the pressure relief plate 7 is used to prevent foreign matter from entering from the outside.
Dust sealing is achieved by applying a rubber-based resin 81 to the outer periphery. Next, the operation of the present invention will be explained. If an explosion occurs due to an internal short circuit, etc.
As the internal pressure within the casing 1 increases, the weak portion 10 of the pressure relief plate 7 is bent downward using the stud bolts 5a and 5b as fulcrums as shown in FIG. 4 to release the internal pressure within the casing 1. To prevent the casing 1 from being destroyed.

[Effect of the idea]

The present invention has the above configuration and has the following effects. (1) If the mounting direction of the pressure relief plate and the direction in which the sealing gasket is pressed are the same, if the adhesive force of the pressure relief plate decreases due to some accident, the force pressing the sealing gasket will decrease in proportion to the decrease in adhesive force. become weaker,
The gas sealed inside is likely to leak. However, in the present invention, the pressure relief plate is fitted into the fitting portion with a pressing force applied to the sealing gasket in a direction transverse to the insertion direction of the pressure relief plate.
In other words, the direction in which the pressure release plate is inserted and the direction in which the sealing gasket is pressed are different. Therefore, even if the fixing force of the pressure release plate decreases, the force pressing the sealing gasket does not become weaker in proportion to the decrease in the fixing force. Therefore, the gas sealed inside is less likely to leak. Further, even if the casing wall surface is slightly deformed, the airtightness is not impaired. (2) By appropriately selecting the mounting position of the pressure relief plate, the cross-sectional shape, thickness, area, etc. of the pressure relief plate, it is possible to set the pressure relief operation value over a wide range. (3) Pressure is released by deforming the pressure relief plate, rather than destroying it during pressure relief as with conventional pressure relief plates. This makes it possible to increase the thickness of the pressure relief plate, eliminates the fear of perforation due to corrosion, and improves the reliability of the device. (4) Unlike conventional pressure relief plates, low-cost materials can be used because they do not require as much precision. (5) By changing the fixing point of the mounting flange, the deformation direction of the pressure relief plate, that is, the pressure relief direction can be set arbitrarily.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view of a switch equipped with a pressure relief mechanism according to the present invention, Fig. 2 is a bottom view, and Fig. 3 is a partially enlarged view showing the normal state as seen from the direction of the arrow in Fig. 2. 4 is a partially enlarged sectional view showing the operating state when viewed from the direction of the arrow in FIG. 2, and FIG. 5 is a sectional view of a conventional pressure relief mechanism. 1: Casing, 2: Through hole, 3: Inner peripheral wall, 4:
Outer peripheral wall, 7: Pressure relief plate, 10: Weak portion.

Claims (1)

[Scope of claim for utility model registration] The casing 1 has a recessed part of the wall surface and an inset part 1.
The fitting part 1a is provided with an inner circumferential wall 3 bent from the wall surface of the casing 1 toward the inside of the casing, and a portion surrounded by the inner circumferential wall 3 is provided with a gas vent. A through hole 2 is formed, and a pressure relief plate 7 fixed to the casing 1 has a fitting convex body 7 formed with an outer circumferential wall 4 that fits into the inner circumferential wall 3.
0, a stepped portion 41 is formed on the outer peripheral wall 4, and a mounting flange 6 is formed in a continuous manner via the stepped portion 41, and a sealing member is provided between the inner peripheral wall 3 and the stepped portion 41. With a packing 8 interposed, the sealing packing 8
The pressure relief plate 7 is fitted into the fitting part 1a with a pressing force applied in a lateral direction to the insertion direction of the pressure relief plate 7, and the fixing points of the mounting flange 6 are not arranged evenly to reduce the internal pressure. A pressure relief mechanism characterized by being provided with a fragile portion 10 that deforms when rising and becomes a pressure relief port.