JPH09178599A - Method and equipment for testing airtightness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of test while shortening the test time by setting a container, for receiving an article to be tested and applying a static pressure thereto by introducing a gas, into a liquid thereby eliminating the danger where the cover or a sealing member of a pressure test container is scattered due to gas leak. SOLUTION: A space is formed between a submarine relay and the inner side face of a container 14 and injected with helium gas 13 from a helium compressor 1. At the time of test, the space between a pressure test container 10 and the container 14 is filled with a liquid 12 and the opening 15, 16 of container 10 is sealed by applying a cover 5. Subsequently, gas 13 is injected from the compressor 1. The gas 13 is injected through piping parts 2, 8 into the container 14 and applies a static pressure to the submarine relay. Since the container 10 is filled with water and the liquid 12 has volume compression rate lower than that of gas, the container 10 does not expand significantly even if the inner pressure is 800 atm. In the airtightness test, a helium gas detector 4 detects helium gas leaking into the relay.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for testing an airtight container, and more particularly to a method and an apparatus for testing the airtightness of an airtight container against external pressure.

[0001]

2. Description of the Related Art With respect to a pressure test of a pressure vessel, many proposals have been made on an airtightness test of the vessel when the pressure inside the vessel is high. However, there is less information on the airtightness test of the container against external pressure as compared with the former. As an example of receiving a large pressure from the outside, there are various devices such as a submarine cable and a submarine repeater laid along the submarine cable. Since these devices receive a large hydrostatic pressure at the sea floor, their containers are required to have durability against the hydrostatic pressure and airtightness.

[0002] The present inventor has heretofore performed a hermetic test using a test apparatus shown in FIG. 2 when performing an hermetic test on the pressure-resistant container against the hydrostatic pressure. The method and apparatus will be described below.

The device under test 11 is a submarine repeater. The airtight protective container of this repeater is usually made of a beryllium copper alloy and has a shape of about 20 to 30 cm in diameter,
It is about 60 to 100 centimeters in length. First, an opening is formed in an airtight protection container of a submarine repeater in which an optical fiber amplifier is installed, and a pipe portion 9 is airtightly connected to the opening. The pipe section 9 is connected to the pipe section 3 by the connection section 7, and the pipe section 3 is connected to the helium gas detector 4.

Next, the DUT 11 is placed in a pressure test container 10 made of metal such as stainless steel. The DUT 11 is suspended from the lower surface of the lid 5 by a wire. The opening of the pressure test container 10 is sealed with the lid 5.
Piping portions 8 and 9 penetrate through the lid 5, and the piping portion 8 is connected to the piping portion 2 by a connection portion 6. The piping section 2 is connected to the helium gas compressor 1.

[0005] When performing the test, the helium gas compressor 1
Helium gas is introduced into the pressure test container 10 through the piping sections 2 and 8 and the opening 16 from the opening. The test pressure was 800 atm, which assumes a sea bottom of 8000 meters. After the pressure in the pressure test container 10 reaches this pressure, the pressure is maintained for one hour, and helium is detected by the helium gas detector 4 communicating with the DUT 11. The helium gas detector 4 is a known device, and helium molecules are bent by a magnetic field to select from other gas molecules and count. The portions of the DUT 11 that may leak are the welded portions of the beryllium copper alloy, the soldered portions of the optical fiber takeout portions, and the sealed portions of the electric wire takeout portions using polyethylene or the like. After the test, helium gas is usually collected.

[0006]

However, the above-described airtightness test method and airtightness test apparatus have the following problems. First, a pressure as high as 800 atm is applied, and the gas has a high compression ratio with respect to the external pressure. In particular, a sealing member such as an O-ring that seals the lid 5 installed in the opening of the pressure test container 10 is damaged, a large amount of helium gas is blown out, and the sealing member such as the lid 5 or the O-ring is damaged. There is a risk of scattering and causing an accident.

[0007] Further, depending on the size of the pressure test container 10, the above test apparatus uses a large amount of expensive helium gas, so that the test becomes expensive. After the test, helium is recovered, but loss that cannot be recovered always occurs. Further, if a leak occurs from the pressure test container 10, a large amount of helium gas is lost.

Next, since a large amount of helium gas is used, it takes about one hour with the tester used by the present inventor until the inside of the pressure test container 10 becomes about 800 atm. It takes a long time. All submarine repeaters have been tested, and improving the work efficiency of the airtight test is an important issue.

The present invention solves the above problems and reduces the risk of damage to the pressure test container 10, its lid 5 and the sealing member, and greatly reduces the amount of expensive helium used. It is an object of the present invention to provide a test method and a test apparatus capable of shortening a test time.

[0010]

According to the airtightness test method of the present invention, the DUT is housed in a first container, and the first container is placed in a second container filled with a liquid. This is a method of sealing the second container, injecting gas into the first container to bring the inside of the first container into a high pressure state, and testing the airtight state of the DUT against the external pressure.

Further, the airtightness test apparatus of the present invention comprises a first container for storing a test object, a means for injecting gas into the first container, and an airtightly sealed housing for accommodating the first container. A second container that can be shut off; and a gas detector disposed at a position communicating with the inside of the DUT.

[0012]

Next, a specific embodiment of the present invention will be described with reference to FIG.

First, a configuration example of the test apparatus of the present invention will be described. In FIG. 1, the DUT 11 is the same submarine repeater as in FIG. 2. An opening is formed in the hermetic protection container, and a pipe 9 is connected to the opening by welding, solder sealing, or the like in an airtight manner. The pipe section 9 passes through the lid 5, is connected to the pipe section 3 by the connection section 7, and is further connected to the helium gas detector 4.

The interior of the container 14 in which the submarine repeater is stored is slightly larger than the submarine repeater. A piping portion 9 is hermetically sealed with an O-ring or the like and penetrates the container 14, and a piping portion 8 for injecting gas into the container 14 is similarly hermetically sealed and connected. . The pipe section 8 passes through the inside of the lid 5 and is connected to the pipe section 2 by the connection section 6, and the pipe section 2 is connected to the helium gas compressor 1.

[0015] A space is formed between the submarine repeater and the inner surface of the container 14, into which helium gas is injected from the helium gas compressor 1. At the time of the test, the space between the pressure test container 10 and the container 14 is filled with a liquid, and the lid 5 is installed and sealed at the opening of the pressure test container 10.

In this embodiment, the container 14 is made of a flexible rubber material. As described above, since the space between the pressure test container 10 and the container 14 is filled with the liquid during the test, the container 14
Is required to be a material that does not allow this liquid to permeate. The material may be another polymer material, resin, or metal, and is desirably a material that can be deformed to some extent with helium gas injection. Of course, it is also possible to use a combination of a rubber-based material, a polymer, other resins, and metals. Even a container whose shape is hardly changed can be used because the pressure difference between the inside and the outside of the container is small.

When performing an airtight test, first, an opening is formed in a part of an airtight protection container made of beryllium copper alloy of a submarine repeater in which an optical fiber amplifier is installed, and a pipe portion 9 is welded. And attached. The submarine repeater in this state is housed in a rubber container 14 having substantially the same size as the repeater, a portion through which the piping portion 9 penetrates is sealed with an O-ring, and The part 8 was attached, and the attachment part was similarly sealed.

Next, the pressure test vessel 10 was filled with water to which a rust inhibitor was added. The liquid that fills the space between the pressure test container 10 and the container 14 is not limited to this, and for example, oils used for various hydraulic devices and the like can be used.

In this case, the pipe portions 8 and 9 are pre-penetrated through the lid 5 and are sealed and attached. The submarine repeater has a protrusion on the outer periphery and a lower surface of the lid 5 attached to the lower surface of the lid 5 by a wire or a fixture (not shown), and the wire or the fixture and the container 14 are sealed with an O-ring or polyethylene. . Put this lid 5 in the pressure test vessel 1
0, and the pressure test container 10 and the lid 5 were hermetically sealed. At this time, it is desirable to fill the inside of the pressure test container 10 with water as much as possible and leave no air.

The container 14 for separating helium gas and water is used.
May be one that can withstand a pressure difference of several atmospheres. This is because the pressure inside the container 14 into which the helium gas is injected and the pressure outside the container 14 filled with water rises at about the same pressure as the helium gas is injected, and even if the pressure is large, the pressure difference is large. Below a few atmospheres. When the desired pressure is reached, the pressure in both parts will be equal.

After the lid 5 was sealed, helium gas was injected from the helium gas compressor 1. The helium gas is injected into the container 14 via the piping portions 2 and 8 and applies hydrostatic pressure to the submarine repeater. However, since the inside of the pressure test container 10 is filled with water, and the volume compression ratio of the liquid is much smaller than that of the gas, the inside of the container 14 does not expand so much even when the inside reaches 800 atm.

In the airtight test, the state is maintained for one hour after the pressure in the container 14 becomes 800 atm. The helium gas detector 4 connected to the inside of the submarine repeater by the pipes 9 and 3 enters the inside of the repeater. Leaked helium was detected and tested for air tightness.

In the submarine repeater satisfying the standard, the pipe portion 9 is removed, and a pin is driven into the opening thereof.
A sealing means such as a welded seal and an O-ring are used in combination for sealing.

In this airtight test, helium is injected into a small space between the airtight protection container of the submarine repeater and the inner surface of the container 14, so that the amount of helium to be used is much smaller than before, and the amount of helium used is 800. The time to reach atmospheric pressure is also significantly shorter. Specifically, the same pressure test container 1 as in FIG.
When 0 was used, the amount of helium used could be reduced to one-tenth or less, and the time required to reach 800 atm was reduced to about one-tenth as compared with the conventional method of the present inventor. Furthermore, since the amount of helium is small, the amount of helium lost during recovery is naturally very small.

Even when helium gas leaks from the container 14, since the pressure test container 10 is filled with water, a large amount of helium gas blows out and the lid 5 or the sealing member splatters, causing an accident. Will not occur.

It is desirable that all parts other than the container 14 in the pressure test container 10 are filled with water. However, even if a small amount of air remains, the above effect is not lost.

For the various types of sealing described so far, one or a plurality of appropriate types can be selected according to the necessity of a sealing portion such as resin sealing of polyethylene or the like, an O-ring and a metal fitting, soldering, welding, or the like.

As described above, in the airtightness test method and test apparatus of the present invention, a container for installing a device under test and introducing gas to apply a hydrostatic pressure to the device under test is further provided with a liquid container. As a result, it was possible to eliminate the danger that the lid and the sealing member of the pressure test container would be scattered by gas leakage. In addition, when expensive helium is used, the amount used is smaller than that of the conventional method, so that the test cost and the test time can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a specific example of an airtightness test apparatus according to the present invention.

FIG. 2 is a configuration diagram showing an example of an airtightness test device conventionally performed by the inventor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Helium compressor 2, 3, 8, 9 Piping part 4 Helium gas detector 5 Lid 6, 7 Connection part 10 Pressure test container 11 Product under test 12 Liquid 13 Helium gas 14 Container 15, 16 Opening

Claims (7)

[Claims] 1. A device under test is stored in a first container,
The second container is installed in the second container filled with the liquid.
The airtightness test method, wherein the container is sealed, gas is injected into the first container to bring the inside of the first container into a high pressure state, and the airtightness state of the DUT against external pressure is tested. 2. The airtightness test method according to claim 1, wherein the gastightness of the DUT is tested by a gas detector arranged at a position communicating with the inside of the DUT. 3. The airtightness test method according to claim 1, wherein the gas is helium. 4. The airtightness test method according to claim 1, wherein a space other than the first container is filled with a liquid inside the sealed second container. 5. A first container for accommodating a DUT, and the first container.
A means for injecting gas into the container, a second container capable of accommodating the first container and hermetically sealing it, and a gas detector arranged at a position communicating with the inside of the DUT. An airtightness test device characterized by being provided. 6. The airtightness test apparatus according to claim 5, wherein the material used for the first container is a material that does not allow the liquid filled in the second container to pass through during the test. 7. The airtightness test apparatus according to claim 5 or 6, wherein the first container is a container whose volume can change with the injection of gas.