Helium Leak Test
The helium leak test is a measurement method using a leak detection system to detect leakage from a change in helium partial pressure in a vacuum.
In contrast to other inspection methods, which determines by volume, pressure, degree of vacuum, the helium leak test obtains high sensitivity and high accuracy without depending on the skills of operators.
Even if the leakage becomes small, it is not necessary to take a long time to judge, so it is possible to do the inspection quickly.
Besides, helium gas is safe and inert, which allows clean inspections that are eco-friendly.
Leak Test other than Helium Leak Test
(1)Pressurization test
| (a)Pressure build-up test | (b)Differential pressure test(AirLeak) | ©Bubble test |
| After the test object is pressurized and closed, the total amount of leakage is confirmed by the pressure drop. | After the test object is pressurized with air and closed, compare the pressure drop with simulated leak work. | The test object is pressurized with air and submerged in the water. The leakage is confirmed by bubbles coming out of the test object. |
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| (d)Hydraulic pressure divisor test | (e)Soap bubble test. | (f)Halogen gas probe test |
| Water leakage is confirmed by applying water pressure to the test object. | The test object is pressurized with air. The leakage is confirmed by the visual inspection of bubbles coming out of the test object. | The test object is pressurized with refrigerant gas. The leakage is checked using a gas detector. |
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| (g)Fluorescent dye Penetrate (FPI dye) test. | ||
| The test object is pressurized with a penetrant (colored) and air. The leakage is visually inspected. | ||
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(2)Vacuum test
| (h)Vacuum build-up test | (i)Liquid coating test（alcohol check） |
| The test object is closed in a vacuum. The total amount of leakage is checked by the pressure rise. The leakage point cannot be identified. |
While evacuating, apply alcohol on the test object, and the change in the ultimate pressure is checked. A method to find a leakage point. |
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Comparison of characteristics of leak test methods
■ Characteristics of each test method
