JPH0481632A - Method for confining helium gas in open container - Google Patents

Abstract

PURPOSE:To secure the predetermined concn. of He in an open container by providing a double hood to the opening part of the open container to supply air to the space of the hood to pressurize the same and supplying He to the open container to seal the same in the container. CONSTITUTION:The opening part 11 of a container 10 to be inspected is hermetically closed by the first hood 1 and the second hood 2 is arranged outside the hood 1. Air sealing piping 3 is connected to the hood 2 to pressurize the same and, finally He 5 is sealed in the container 10 to be inspected from helium gas sealing piping 6. Air 4 is supplied to the region B between both hoods by the air sealing piping to hold the pressure of the region B. The concn. of He in a region A is raised by the sealing of He and the region A is moved to the outside of the container 10 is expand. At this time, the supply of He is stopped. The concn. of He in the region A becomes 50% or more and the outflow of the helium gas 5 to a region C is suppressed by the pressure of the region B and the concn. of the helium gas in the container can be secured by a simple method.

Description

DETAILED DESCRIPTION OF THE INVENTION; Industrial Application Field The present invention relates to a method for confining helium gas in an open vessel applied to a helium leak test of a pressure vessel having an opening.

[Prior art: 5 methods of sealing helium gas in a conventional open container to be tested will be explained with reference to FIGS. 3(a) and 3(b).

The open container IO in FIGS. 3(a) and 3(b) has an opening 11 and a test section 12, is connected to a helium-filled pipe 6, and has a vacuum box 13 disposed in the test section 12, When helium leaking into the vacuum box 13 is detected by a detector, the state of the test area 12 is determined.

In the conventional method shown in FIG. 3(a), the temporary cover 14 is attached to the opening 11 by welding 15, and
In the conventional method shown in (b), the temporary M14 is attached to the opening 11 through the O-ring 16 by a mechanical method.
In both cases, after the open container 10 was sealed, helium gas was sealed inside the open container 10.

[Problem to be solved by the invention]

The conventional helium gas containment method using a temporary lid had the following problems.

(1) There are various sizes and shapes of openings, and it is necessary to manufacture a temporary lid each time according to the size and shape.

(2) When fixing by welding: To avoid leaving any traces after removing the temporary lid of the test container, extra length is required in advance, and it takes 6 or 2 steps to confirm the soundness of the temporary lid removal marks. It takes.

(3) When fixing mechanically using an O-ring,
A jig is required to generate the fixing force for the temporary lid.

(4) In addition, the temporary lid is usually made of the same material as the test container (carbon or stainless steel mouth), and depending on its size, it may have a diameter of over 1,000 mm (φ!000 mm) and must be handled manually. may not be possible.

The uninvented object is to solve the above problem.

[Means for Solving the Problems] The method for sealing helium gas in an open container of the present invention provides an open container that has an opening and is a container to be tested for a helium leak test. After gluing the hood and sealing the opening, a second sheet-like hood is placed outside the hood and bonded to the open container, and air is fed between the first and second hoods to generate a force U. 7. After 3' and -z, nickel helium gas is pumped and sealed in the closed container.

Dual action: In the above, the opening of the open container is doubly provided with a first hood and a second foot, and air is fed between the first hood and the second hood to pressurize it by '-1'. After this, since helium gas is supplied and sealed into the open container, a higher pressure can be maintained in the open container than when only the first hood is provided, and the helium gas concentration is kept at a predetermined concentration. It can be done.

As a result of the above, it is possible to eliminate the need for attaching a temporary lid, which takes conventional work time, and to secure the helium gas concentration in the open container at a predetermined concentration using a simple method.

〔Example〕

An embodiment of the present invention will be explained with reference to FIG.

This embodiment shown in No. 17 has an opening 11 and a test section 12 to which a helium-filled pipe 6 is connected, and a vacuum box 13 for helium leak detection is installed in the test section I2. An open container S, which is the test container 10, is placed in FIG.
As shown, a 17th door 1 made of a polyethylene sheet or the like is placed in the opening 11 of the test container 10 to seal the opening 11, and then a polyethylene sheet or the like is similarly placed on the outside of the opening 11. A second foot 2 is provided. Next, after connecting the air sealing pipe 3 to the second hood 2 L/7L,
Air 4 is fed between the first hood 1 and the second hood 2 from the same pipe 3C2 and pressurized. Finally, as shown in the first section (b), helium gas 5 is sent into the test container 10 from the helium gas filling pipe 6 and sealed therein.

In the above, the 17th hood 1 and the second hood 2 are placed in the opening 11 of the container 10 to be tested, and are each attached to the outer peripheral surface of the container 10 using vinyl tape.

Air 4 is supplied to the region B formed between the first hood 1 and the second hood 2 through an air sealing pipe 3;
As a result, region B is pressurized to approximately 0.2 kg/crll G, and this pressure is maintained.

Next, when helium gas is sealed from the helium gas filling pipe 6, the helium concentration increases in the area A in the test container 10, and when helium gas 5 is continued to be filled, the first foot 1 and the second hood 2 moves to the outside of the container 10 and expands as shown in FIG. 1(b). Here helium scum 5
supply will be stopped. When the state shown in Fig. 1(b) is reached, the helium gas concentration in region A becomes 50% or more, and the outflow of helium gas 5 to region C is suppressed by the pressure nozzle J in region B. Helium leak test conditions are created.

Note that Section 211(at (b) is the same as that in FIG. 1(a), (
The type of gas and the pressurized state in each region A, B, and C shown in b) are shown.

As a result of the above, it is possible to eliminate the need for attaching a temporary lid, which takes up conventional work time, and to ensure the helium gas concentration within the container by the simple method of providing a double hood.

〔Effect of the invention〕

Method for containing helium gas in an open container of the present invention:
By installing a nitrogen foot at the opening of the open container, supplying air between the feet to pressurize it, and supplying and sealing helium gas inside the open container, the work time can be reduced compared to the conventional work time. It is possible to maintain a predetermined concentration of helium sludge in an open container using a simple method without the need to attach a temporary lid.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the states of areas A, B, and C according to the above-mentioned embodiment, and FIG. 3 is an explanatory diagram of a conventional method. 1...First hood, 2...Second hood, 3...
・Air-filled piping, 4...Air, 5...Helium gas, 6...Helium gas-filled piping, 10...Test container, 12...Test part, 13...
・Vacuum box. Agent: Patent attorney Akira Sakama, 2 people, 3 figures (ωtsu(shi))

Claims (1)

[Claims] In an open container that has an opening and is a container to be tested in a helium leak test, a first sheet-shaped hood is adhered to the opening to seal the opening, and then a second sheet-shaped hood is placed outside the opening. The opening method is characterized in that the first hood and the second hood are pressurized by supplying air between the first hood and the second hood, and then helium gas is supplied and sealed into the open container. How to contain helium gas in a container.