JPS6166507A - Discharge pressure device of enclosed switch board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a pressure relief device for operating a pressure relief mechanism of a switchboard more efficiently.

[Background of the invention]

When a short circuit occurs inside a closed switchboard due to an accident and an arc is generated, the internal pressure increases due to the internal arc energy and an eruption occurs. For this reason, it is necessary to provide a pressure relief plate on the ceiling to release the internal ejection pressure to the outside air as quickly as possible.

Conventionally, pressure relief plates installed in the ceiling are of the so-called single-open type, with a single plate hinged on one side, but if the opening is made larger, the weight becomes heavier and the pressure relief operation is delayed. , the strength of the opening has weakened. On the other hand, if the opening is made smaller, the increase in internal pressure cannot be followed, and there is a risk that other parts, such as the door or side panels, may be affected by the pressure, and may be damaged or scattered. Examples of devices equipped with a pressure relief mechanism include Japanese Utility Model Application Publication No. 57-159308 and Japanese Utility Model Application Publication No. 59-8203.

[Purpose of the invention]

The purpose of the present invention is to quickly reduce the pressure when an internal arc occurs, and also to use the outflow jet from the initially opened pressure relief plate to quickly open the other pressure relief plate, thereby reducing the pressure inside the panel. It is an object of the present invention to provide a closed switchboard equipped with a pressure relief mechanism that reduces pressure in a short time and prevents deformation, scattering, etc.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

In Figures 1 and 2, an opening 2 is provided in the ceiling of the closed switchboard frame 1, and the opening 2 is brought into close contact with the metal edge of the opening 2, and metals collide with each other due to the rotation of the pressure release plate. A cushion-cum-drip-proof sheet 3 is closely attached to prevent water damage. A rotation hinge 6 and a mounting plate 7 are provided on the secondary pressure relief plate 4 and the -order pressure plate 5, respectively, so as to close the opening 2 and the seat 3 from above, and are fixed to the frame 1 with bolts 8 or the like.

When the primary and secondary pressure relief plates are pushed up and rotated by the increase in internal pressure P, they hit the stopper 9 provided on the stopper fitting 10. At this time, a discharge sensor 11 is provided on the -order pressure plate 5 side, the -order pressure plate is opened, and the stopper 9
When it hits, an open indication is transmitted to a remote monitoring board, etc., and used on the top of the breaker, etc.

Next, the operation will be explained. When the internal pressure P is generated, the primary pressure relief plate 5 having the dimension tl overcomes the fixing screw 12 and opens. Due to this opening, the gas ejected from the opening on the side of the secondary pressure relief plate 4 is concentrated and released, but due to this pushing up force, the secondary pressure relief plate 4 is subsequently opened, opening in the direction of opening in both directions. The remaining ejected gas is released from this hole. FIG. 3 shows the relationship between pressure P and time T when an opening is provided.

If the pressure relief plate is opened as soon as possible before P becomes too large, deformation and scattering of internal parts of the panel can be prevented. However, since the internal pressure is applied to the surface area inside the board, tl
Even if t2 is made extremely large, the opening time will not become smaller.
In experiments, it seems that about 3 pairs is most effective. Furthermore, the opening time can be minimized by making the material of the -order pressure plate 5 low in specific gravity (for example, aluminum) and by reducing the frictional force of the hinge.

In addition, by overlapping the seam of the two halves and enlarging the seam opening, the strength of the seam is increased and the strength can be ensured even if someone steps on the finished plate. .

〔Effect of the invention〕

According to the present invention, the pressure relief plate opens more quickly, the increase in pressure inside the plate becomes smaller, and the plate is prevented from deforming and scattering, thereby increasing safety.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a perspective view and a sectional view of an embodiment of the present invention, and FIG. 3 is a diagram showing the relationship between the pressure at the opening and time. DESCRIPTION OF SYMBOLS 1... Panel frame, 2... Opening, 4... Secondary pressure relief plate, 5... -order pressure plate, 6... Hinge, 8...
Fixing bolt, 9...stopper, 11...sensor,
12...Fixing screw.

Claims (1)

[Scope of Claims] 1. A power distribution box having an opening in the ceiling, including a rotatable hinge provided at both ends of the opening, and a flap that is divided into two parts and wrapped at the joint to cover the opening. A pressure relief device for a closed switchboard, characterized by comprising a pressure plate. 2. Pressure relief of a closed switchboard according to claim 1, characterized in that, of the two divided pressure relief plates, the upper one is smaller than the lower one and has an unequal load distribution. Device.