JPH0236302Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention is an electrical device that seals a gas in a container, and when the internal pressure exceeds a predetermined pressure, the device is used until the internal pressure falls below the predetermined pressure. This invention relates to a pressure relief device that releases a gas and then automatically returns to its original state.

[Prior art]

2. Description of the Related Art Conventionally, there is a structure shown in FIG. 1 as a general structure of an automatic return type pressure relief device used in gas-filled electrical equipment. In the figure, reference numeral 1 denotes a pressure relief device case, which is fixed by bolts 6 to a mounting seat 7a of a container 7 of an electrical equipment main body via a flange 1a. 2 is a pressure release cover having a stud 2a; 3 is a coil spring inserted into the stud 2a;
It is hung between a seat 1b provided on the stud 2a and a nut 5 screwed onto the stud 2a. 4 is cover 2
A coil spring 3 is set so that a predetermined compressive force can be obtained on the gasket surface by a gasket clamped between the end surface of the case 1 and the end surface of the case 1. Note that this gasket 4 is bonded to the cover 2 with an elastic adhesive.

Next, the operation will be explained. When the compression force of the coil spring 3 is T, the internal gas pressure is P, and the internal cross-sectional area of the case 1 is S, in a steady state, T>
A compressive force of T-PxS acts on the end faces of the gasket 4 and the case 1, providing a sealing effect to prevent internal gas from leaking. Here, when the internal gas pressure exceeds a predetermined value, if the internal gas pressure is P ₁ , then T < P ₁ × S, and a gap is created where the gasket 4 surface and the end surface of the case 1 were in contact. gas is generated and the enclosed gas is released to the outside. When the internal gas pressure falls below a predetermined value due to this gas release, the relationship T>P×S is established again, and a compressive force acts on the end faces of the gasket 4 and the case 1, creating a sealing effect that prevents the internal gas from leaking. Occur.

By the way, in this conventional pressure relief device, as shown in FIG. 2, the contact surface between the gasket 4 and the end surface of the case 1 is composed of one flat surface, so that the T-P
When the value of xS is small, it is difficult to expect perfect sealing performance. In addition, if dust etc. is caught, 1
Since the gas seal is formed on two flat surfaces, it has drawbacks such as being easily affected by dust.

[Summary of the idea]

This idea was made to eliminate the drawbacks of the conventional device as described above, and by creating a groove on the end surface of the case 1 that contacts the gasket 4,
The purpose is to provide a pressure relief device with highly reliable sealing performance.

[Example of idea]

An embodiment of this invention will be described below with reference to the drawings. In FIGS. 3 and 4, numerals 1 to 7 indicate the same parts as those in FIG. 1, so their explanations will be omitted. 8 is a V-shaped groove provided on the end surface of the case 1 in contact with the gasket 4, and 9 is grease that fills this groove 8 and is applied to the end surface of the case 1 in contact with the gasket 4.

Next, the operation of the pressure relief device will be explained.
When the internal gas pressure is P, a compressive force of T-P×S acts on the end faces of the gasket 4 and the case 1, thereby creating a gas seal. Also, the internal gas pressure
When the temperature reaches P ₁ , a gap is created between the gasket 4 surface and the end surface of the case 1, and the sealed gas is released to the outside. After this pressure release, if the internal gas pressure falls below a predetermined value, the cover 2 automatically returns to perform gas sealing again.

Therefore, in the present invention, since the end surface of the case 1 in contact with the gasket 4 has a V-shaped groove 8, the compressive force on the gasket is weak at the groove 8, and strong at the two peaks that sandwich the groove 8. Because it is pressed down, a sealing effect similar to that of a double seal structure can be expected.

Next, think about what happens if you bite into a piece of garbage.
In practice, it is difficult to imagine that a piece of dirt as long as the width of the gasket 4 will be caught, and in most cases it is a very short piece of dirt. Therefore, even if dirt gets caught, the structure is close to a double seal structure as described above, so even if the gas seal on the pressing surface of either the outer or inner gasket 4 becomes impossible, the groove will remain intact. Since the pressing surface of the other gasket 4 is sound after this point, the gas sealing ability can be maintained. Furthermore, since the grease 9 is present on the end face of the case 1 in contact with the gasket 4 and in the groove 8, very minute gaps can be filled with the grease, so that the sealing ability is further improved. Also, the pressure relief device operates and gasket 4 and case 1
Case 1 in which the grease 9 filling the groove 8 comes into contact with the gasket 4 when the cover 2 returns to its original state even if the grease 9 on the end face becomes diluted due to gas release.
It serves as a source of grease supply to the end face of the valve, and is effective in maintaining the gas sealing effect after the pressure relief device operates.

In the above embodiment, the number of grooves 8 is one, but a plurality of grooves 8 may be provided.
The shape is not V-shaped, but may be other shapes such as U-shaped.

[Effect of idea]

As described above, according to this invention, gasket 4
By grooving the end surface of the case 1 that contacts the casing 1, and filling and applying grease to the groove and the end surface, a pressure relief device with a highly reliable gas seal can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view showing a conventional pressure relief device, Fig. 2 is an enlarged view showing the gasket and case end face during gas sealing in the conventional example, and Fig. 3 is a pressure relief device according to an embodiment of this invention. FIG. 4 is an enlarged view showing the gasket and the end face of the case when the gas is sealed according to the present invention. In the figure, 1 is the pressure relief device case, 2 is the pressure relief cover,
3 is a coil spring, 4 is a gasket, 7 is a container of the electrical equipment body, 8 is a groove, and 9 is grease. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] This is a pressure relief cover that is attached to the main body of electrical equipment containing gas and has a pressure release cover attached to the pressure release device case via a gasket.When the pressure inside the equipment exceeds a predetermined value, the internal gas is released from the gasket surface. In a pressure relief device that maintains the internal pressure of electrical equipment within a predetermined range, a V-shaped groove is machined on the end surface of the pressure relief device case side that contacts the gasket attached to the pressure relief cover. A pressure relief device characterized by filling a V-shaped groove with grease.