New development of air tightness leak detection technology and technology

Key words: air tightness detector, tightness leak detector, hydrogen leak detector

Hydrogen, diluted with nitrogen, can be used to detect and measure leakage and tightness of products.

The hydrogen leak detector is an important component of the air tightness detector, which is applied to the product quality assurance in a wide range of industries. Since nothing is absolutely leak free, tightness testing and leak detection can basically ensure that the product has been tested and the maximum permissible leakage requirements. The process ensures that flammable, toxic or corrosive substances in containers are safely confined to containers. It can also determine a system, such as brakes, air conditioning units of liquid or gas, or hydraulic valves will stay there.

Corrosion caused by water vapor detection and water vapor

For many years, a simpler method of water immersion and pressure attenuation measurement has always been the most popular. Each of them has the smallest investment advantage, but also has its disadvantages. Water immersion. An object immersed in water can effectively determine whether there is any leak. Theoretically, the source of bubbles and the number of bubbles per minute can indicate the size of bubbles. But a small leak may cause some or tiny bubbles. If the leak is in a groove, the air can be collected and maintained in the cavity. Or, bubbles may be attached to the test object rather than to the surface. Water immersion is also very dependent on the responsibility of manufacturers. When an object is artificially immersed in water, it can pull down from the surrounding air and pull bubbles away from a leaking bubble. The tester must wait until the object has cleared its non leakage related bubbles. And a small leak object may not be observed. Finally, the water will corrode or damage the equipment to be measured.

The pressure attenuates. This technique detects a pressure drop indicating leakage. The greater the drop, the greater the leakage. The method is dry and easy to automate. But it can not accurately determine the source of leakage, and its accuracy is affected by some variables, including quantity, material and temperature. It is possible for a large capacity object to take too long a cycle time; plastic bottles and rubber parts can be used to counteract pressure attenuation by reducing volume. The temperature rise and pressure rise inside the test object need to wait for stability. Processing and environmental conditions can also increase or lower the temperature of the device under test and skew results.

Tracer gas helium

The lightest inert gas exists in air only a very small amount (~ 4 ppm). The helium mass spectrometer is very sensitive to the trace gas. These instruments are usually equipped with an external pump, which creates a vacuum interested object and detects gas as it escapes. But mass spectrometer requires careful, expensive maintenance, and preferably kept in the laboratory.

Hydrogen. High concentration of hydrogen is highly inflammable, but it can be inert by dilution with nitrogen. The standard hydrogen nitrogen mixture is a common welding protection gas. According to iso10156, any mixture of hydrogen and nitrogen < 5.7% hydrogen is classified as non flammable. For the purpose of leak testing, most natural gas suppliers provide a 5% hydrogen-95% nitrogen mixture. The lightest known element, the viscosity of half of the air or helium, makes it rapidly spread the whole test object, and it is easier to penetrate the leak, and the nozzle is much easier than any other tracer gas. The cost of hydrogen detectors is much lower than that of most mass spectrometers.

Yuan Chi has successfully developed a new type of hydrogen detector, which has high sensitivity and selectivity to hydrogen. The device is also strong enough for industrial use and can detect leakage rate down to 5 x 10-7 ml / sec. They don't need many engineers to operate them. The gas is simply filled into the test piece and used a hand probe connected to the detector to search for leakage, when the tip of the probe approaches the leak location. The hydrogen tightness test can automatically correspond and give the leak detection result. In Japan, auto parts manufacturers have started using hydrogen leak detectors to test their products, saving cycle time and money. Obviously, there are many options for leak detection, leak detection and measurement. But for ease of use and cost effectiveness, hydrogen has great advantages.