JP2575975Y2 - Airtight tank - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an airtight tank, which can properly perform a leak test for checking airtightness.

[0002]

2. Description of the Related Art An airtight tank is used for an electric device such as an oil-filled transformer which has a structure in which a transformer main body is housed in an airtight space and filled with insulating oil. To make an airtight tank, the tank is divided into several parts, and these divided tanks are joined by welding the respective flange parts.

As shown in FIG. 2 (a), an airtight tank is manufactured by manufacturing a lower tank 1 as a tank body and an upper tank 2 as a bushing pocket and welding the flange portions 1a and 2a. The lower tank 3 and the upper tank 4 are manufactured as shown in FIG.
And the flange portion 4a.

[0004] The flange of the welded tank is shown in FIG.
It is configured as shown in (a) and (b). FIG.
The flange shown in FIG. 1A has a structure in which the asbestos yarn 10 is interposed between the flanges 1a and 2a.
A welded portion 11 is provided between the outer peripheral portions of a and 2a. The flange shown in FIG. 3B has a gasket 12 positioned by a gasket stopper 13 bonded to one flange 1a, and an asbestos yarn 10 for preventing spatter generated during welding from damaging the gasket 12. With the flanges 1a, 2
The welding part 11 is provided between the outer peripheral parts of a.

[0005] Then, a leak inspection of the welded portion is performed. The leak test is performed on the upper tank 2 as shown in FIG.
A temporary lid is attached to the flange 5 for attaching the bushing 6 on the upper surface of the slab, or a temporary lid is attached to the flange 7 for attaching components as shown in FIG. Later, FIGS. 2A and 2B
The valves 8 and 9 are opened to fill the tank with nitrogen gas, soap water is applied to the outer surface of the welded portion, and the presence or absence of bubbles is checked to check for gas leakage and poor welding.

[0006]

[Problems to be Solved by the Invention] However, a temporary lid must be used when performing a leak test, and in a large-capacity transformer, the number of flanges to be welded after a product completion test is large. It takes a lot of time to prepare for leak inspection, because the flanges of the parts may be welded on site. In the case of using a gasket as shown in FIG. 3 (b), the presence of the gasket does not allow nitrogen gas to reach the space between the gasket and the welded portion. Can not.

Accordingly, an object of the present invention is to provide an airtight tank that solves the above problem.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the structure of the present invention is such that the butt portions of a plurality of tank portions forming a single tank by butt-joining are surrounded. In an airtight tank provided with a flange portion and a welded portion for connecting the flange portions to each other along the entire outer periphery of the flange portion, a flange portion is formed to form an airtight space between the butted flange portions. A seal member is interposed between the seal portions over the entire inner periphery of the flange portion, and a through-hole is provided for communicating with an airtight space formed between the welded portion and the seal member and the outside of the flange. A plug for opening or airtightly closing the hole is provided.

[0009]

When inspecting for leakage at the welded portion, the plug is removed and nitrogen gas or the like is injected into the airtight space from the through hole to increase the pressure in the airtight space. Then, by applying soapy water or the like to the outer surface of the welded portion, the presence or absence of outgassing from the welded portion is inspected. After the inspection, the airtightness in the airtight space is maintained by installing a plug.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. In this embodiment, since a part of the conventional airtight tank shown in FIG. 3B is improved, the same parts as those of the related art are denoted by the same reference numerals, and description thereof will be omitted. Only different parts will be described.

FIG. 1 shows the structure of the airtight tank according to the present invention. A portion surrounded by the pair of flange portions 1a, 2a, the gasket 12, and the welded portion 11 forms an airtight space 14. For this reason, nitrogen gas is injected into the hermetic space 14 and pressurized, and the pressurized nitrogen gas can be inspected for leakage from the welded portion 11.

In order to allow nitrogen gas to be injected into the hermetic space 14, a through hole 15 for communicating the hermetic space 14 with the outside thereof is formed in the upper flange portion 2a. On the through hole 15, a pedestal 17 having a screw hole 16 is welded to the flange 2a.
Then, the plug 1 having a screw portion to be screwed into the screw hole 16
8 is detachably screwed into the pedestal 17. Plug 1
8 has a circumferential groove 19 formed therein, and an O-ring 20 for maintaining airtightness between the plug 18 and the pedestal 17 is provided in the circumferential groove 19.
Housed within.

Next, the operation of the airtight tank will be described.
In order to inspect the welded portion for leakage, the plug 18 is turned and pulled out of the pedestal 17, and then a metal fitting attached to the tip of the pressurizing tube is screwed into the screw hole 16 to connect the end of the tube to the pedestal 17. . Then, nitrogen gas is sent into the hermetic space 14 through the tube, and
Increase pressure inside. Because the volume of the airtight space 14 is small,
The amount of nitrogen gas is small, and the time for pressurization is short. When the airtight space 14 is pressurized,
When a soap solution is applied to the outer surface of the steel sheet, air bubbles are generated in a portion where leakage occurs, so that a defective welding portion can be easily found.

When the leak test is completed, the fitting at the tip of the tube is removed from the pedestal 17, and the plug 18 is screwed into the screw hole 16 of the pedestal 17. Since the O-ring 20 is interposed between the plug 18 and the pedestal 17, airtightness in the airtight space 14 is maintained.

The seal member is not limited to a gasket, but various types can be used.

[0016]

As can be understood from the above description, according to the hermetic tank of the present invention, gas is injected only into the hermetic space surrounded by the flange portion, the seal member, and the welded portion to pressurize the entire tank. Since there is no need to pressurize, there is no need to attach a temporary lid or the like, so that a lot of time is not required for preparing for a leak test, and the time is short. In addition, since the volume of the airtight space is small, the amount of gas used for leak inspection can be reduced,
Pressurization time is also reduced. Furthermore, in the case of a structure in which a gasket is provided inside the welded portion, conventionally, there was a problem that the pressure was not directly applied to the welded portion due to the presence of the gasket. It is possible to inspect the leak of the part.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an airtight tank according to the present invention.

FIG. 2 is an external view of an airtight tank.

FIG. 3 is a cross-sectional view showing a joint of a conventional airtight tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lower tank 2 ... Upper tank 1a, 2a ... Flange part 11 ... Welded part 12 ... Gasket 14 ... Airtight space 15 ... Through hole 17 ... Pedestal 18 ... Plug 20 ... O-ring

Claims (1)

(57) [Scope of request for utility model registration] A flange is provided so as to surround each abutting portion in a plurality of tank portions forming one tank by being abutted and joined, and the flange portions are mutually connected along the entire outer periphery of the flange portion. In a hermetic tank provided with a welded portion for joining to a sealing member, a sealing member is provided between the flange portions to form an airtight space between the butted flange portions and over the entire inner periphery of the flange portion. And a through hole communicating with the outside of the flange and an airtight space formed between the welded portion and the seal member is provided, and a plug for opening or airtightly closing the through hole is provided. Airtight tank.