JPH01227035A - Leak tester - Google Patents

Abstract

PURPOSE:To detect a leak of a body to be tested, by a leak detector, by a method wherein the body to be tested which is filled up with compressed air and a trace gas is immersed in a liquid of a testing vessel wherein the liquid is held, and the inside of the testing vessel is exhausted to have a negative pressure. CONSTITUTION:An opening of a testing vessel 1 wherein a liquid 2 is held is closed airtightly by a cover 3. A body 5 to be tested is filled up with compressed air and a trace gas 4 and immersed in the liquid 2. The inside of the vessel 1 closed hermetically by the cover 3 is exhausted by driving a pump 8 for exhaustion. When there is any leak from the body 5 to be tested, the trace gas 4 leaks out with air bubbles 6, and it is detected by a leak detector 7. The generation of the air bubbles and the frequency thereof are increased by setting the inside of the vessel 1 to have a negative pressure. Since the trace gas is detected by the leak detector 7, it is unnecessary to observe the air bubbles by the eye, the leak can be detected highly precisely and reliably, and a time of inspection can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a submerged leak tester.

[Conventional technology]

There are various methods known to test for leaks in a test object, but the easiest method is to immerse the test object filled with compressed air in a water tank, and then the test object is leaked to the surface. There is a submersion test method that observes air bubbles.

[Problem to be solved by the invention]

However, the above-mentioned submersion test method is a visual inspection in which air bubbles are judged by looking at them, so it cannot be automated, and if the inspector overlooks it or the air bubbles are small and do not rise to the surface, There was a problem in that leaks were sometimes not detected and detection reliability was low.6 Also, the sensitivity for leaks was low and inspection took a long time.

Therefore, the present invention solves the above-mentioned problems and provides a highly reliable leak tester that can automatically detect leak gas from a test object in a short time with high accuracy and with a simple configuration. The purpose is to

[Means for solving problem n]

In order to achieve the above-mentioned object, the present invention includes a test container which is a closed container, stores a liquid, and in which a test object filled with compressed air and trace gas is immersed, and the inside of this test container. It is composed of an exhaust pump that evacuates to a negative pressure, and a leak detector that detects the trace gas that comes out of the test object together with bubbles.

[Effect]

In this invention, since trace gas is detected by a leak detector, visual observation of bubbles is not necessary. When negative pressure is applied inside the test container, the size and frequency of bubbles generated increases. Therefore, the location of the leak can be easily identified and the inspection time can be shortened.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

The accompanying drawing is a configuration diagram showing one embodiment of a leak tester according to the present invention. In the figure, reference numeral 1 denotes a test container containing a liquid 2, for example water, and the opening of this container 1 is hermetically closed with a lid 3.

The test object 5 is compressed air and trace gas (e.g. He) 4
and immersed in the liquid 2. Connected to the test container 1 are a leak detector 7 that detects the trace gas 4 coming out of the test object 5 together with air bubbles 6, and an exhaust pump 8 that exhausts the air inside the test container 1 to create a negative pressure. ing. 9 is an O-ring, 10a and 10b are connecting pipes, 1
1a and 11b are pulps.

Next, a method of testing for leaks using the leak tester having such a configuration will be described.

First, a liquid 2 is stored in a test container 1, a test object 5 filled with compressed air and trace gas 4 is immersed therein, and the test container 1 is sealed with a lid 3. Next, the pulp 11a is opened and the exhaust pump 8 is driven to exhaust the air inside the test container 1, thereby creating a negative pressure inside the test container 1. When a predetermined negative/positive value is reached, the pump 8 is stopped, the pulp 11a is closed, and then the pulp 11b is opened. In this state, if the trace gas 4 inside the test object 5 leaks together with the bubbles 6, the leak detector 7 detects the gas 4.

Here, the conditions for bubble generation are expressed by the following equation.

P=Pa+d@fshah+2σ/r However, P is the pressure of the bubble, Pa is the pressure on the liquid surface, d is the density of the liquid, h is the depth from the liquid surface to the leak, 1 is the gravity, and σ is the surface tension. , r is the diameter of the leakage hole. bubble 6
is the internal pressure P of the right side of the above equation (pa+a-r-h+
2σ/r), it floats up. Making the inside of the test container 1 negative and positive means making Pa zero,
Therefore, the value on the right side of the above equation becomes smaller. The bubbles 6 float to the surface at a low bubble pressure P, increasing the frequency of bubble generation. Moreover, the bubbles 6 generated by the negative pressure expand and become larger.

〔Effect of the invention〕

As explained above, according to the leak tester according to the present invention, the trace gas leaking from the test object along with the p-bubbles is detected by the leak detector, so there is no need to visually observe the bubbles, and leaks can be detected with high accuracy. It can be detected quickly and reliably, improving the reliability of leak detection and realizing automation. In addition, since the inside of the test container is under negative pressure, the air bubbles that are generated expand and become larger, making it easier to identify the leakage location. It's very large.

[Brief explanation of the drawing]

The accompanying drawings are configuration diagrams showing one embodiment of the present invention. 1. Working - Test container, 2...Liquid, 3... Gravel, II
Body, 4...Trace gas, 5 Fist...Test subject, 6
...Bubble, 7.Fist leak detector, 8.Fist...Exhaust pump.

Claims (1)

[Claims] A test container constitutes a closed container and stores a liquid, and a test object filled with compressed air and trace gas is immersed in the liquid, and an exhaust pump that evacuates the inside of the test container to create a negative pressure. and a leak detector for detecting the trace gas coming out of the test object together with bubbles.