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AIR LEAK TESTING SERVICES & TRAINING
 
 

 

What is Air Leakage?
 
  • Air leakage is the unwanted flow of air through the wall of a vessel or sealed container. Pressure variation from the inside of the vessel to the atmosphere outside the vessel cause the air to flow from higher pressure to lower pressure areas. Air leakage generally occurs from the inside out—from inside an object (higher pressure) to outside the object (lower pressure)— but can also happen from the outside in when ambient atmosphere flows into an evacuated (vacuum) vessel.
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    What is Air Leak Testing?
     
  • Air leak testing is an effective method of determining if a product has been manufactured to meet leak-tight specifications. Microscopic holes, failed seals, and countless other defects can cause air leaks that can lead to significant problems. Everything from automotive radiators to medical devices to sprinkler system components requires air leak testing to ensure proper and safe operation.
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  • In general, air leak testing is clean, non-destructive, and highly repeatable. Air leak tests can be performed on any product that requires air-tight or water-tight construction. It is used not only to detect leaks, but also to provide non-subjective data on leakage rates for further analysis. Air leak testing helps OEMs ensure that their products meet the required leak-tight specifications and helps them find and eliminate design and/or manufacturing flaws.
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    Air Leak Testing Methods
     
    Bubble Test/Submersion Test
     
  • Perhaps the most basic air leak testing method, bubble testing involves pressurizing the part or vessel, submerging it in water, and watching for bubbles caused by escaping air/gas. The size of the leak is directly proportional to the intensity and size of the bubbles created. While submersion testing is effective for locating leaks, it is not effective for accurately measuring or quantifying a leak.
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    Ultrasonic Measurement
     
  • Every leak creates some sort of sound, and the frequency of that sound can be higher or lower depending on the size of the leak. The smaller the leak, the higher the frequency—in many cases, fine leaks emit sound at a frequency that is too high for the human ear to hear. Ultrasonic leak detectors are, most often, handheld devices that are paired with headphones, an adjustable meter, and accompanying computer software; other accessories may be used for certain applications. Ultrasonic measurement can generally detect leaks up to 10-2 scc/s, making them best suited to finding “larger” small leaks, but not very fine leaks. Additionally, these devices cannot actually measure the leak rate, but only provide an estimate based on the frequency of the sound.
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    Pressure Decay Testing
     
  • Pressure decay air leak testing monitors the internal pressure of a sealed part or vessel. The vessel is first pressurized to a predetermined level, usually with dry air or nitrogen, then monitored for set amount of time; any decrease in pressure indicates a leak. The sensitivity of pressure decay testing depends on the total volume of the part being tested, as well as the test time and the resolution of the pressure transducer. In general, this air leak testing method is easier to use than many other processes for leak rates as low as 10-2 scc/s. However, it can be susceptible to environmental and mechanical instability.
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    Vacuum Decay Testing
     
  • Vacuum decay testing is essentially the opposite of pressure decay testing. Instead of pressurizing the part or vessel, it is evacuated and monitored for any increase in pressure caused by test media entering the part. Vacuum decay air leak testing is more sensitive and precise than pressure decay testing, and is less affected by temperature changes or other environmental factors. However, the pressure difference applied to the part during test cannot be greater than 14.7 psiv. Vacuum decay testing may also be susceptible to liquid evaporation and surface outgassing, which can affect and limit sensitivity as traces of humidity/evaporation may increase internal pressure and create a false leak.
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    Helium Sniff Testing
     
  • In helium sniff testing, the part or vessel is pressurized with helium to a predetermined level, then scanned across its surface with a helium sniffer device. Any leak in the vessel will cause an increase in helium concentration at the point of the leak, which will be detected by the sniffer. Helium sniff testing not only locates the leak point, it is also highly sensitive (down to 10-5 scc/s). However, as it generally requires manual operation, it offers slower throughput than some other air leak testing methods, and its effectiveness is limited in environments where background air flow reduces the concentration of tracer gas or in areas where there is a high concentration of helium near the test site.
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    Helium Spray Testing
     
  • For helium spray testing, the part or vessel is evacuated using a pumping system with an integrated helium detector. Any gross leak will prevent the vessel from reaching vacuum. If vacuum is reached successfully, the part is then sprayed with helium; any fine leak will pull helium into the evacuated part. The helium detector will sense the helium and measure the leak rate. Helium spray air leak testing can accurately locate a leak and is highly sensitive (down to 10-6 scc/s). However, multiple leaks may be “masked” if they are located too close to each other, and throughput is generally low.
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    Helium Accumulation Testing
     
  • This air leak testing method starts with the part or vessel inside a sealed enclosure and connected to a pump (or pumps) and a helium sensing device. The vessel is evacuated; if vacuum cannot be reached, a gross leak is present. Once vacuum is achieved, the part is pressurized with helium to a predetermined level. The ambient air within the chamber is continuously mixed via blowers/fans to guarantee uniform air concentration. After a set length of time, air samples are pumped through the helium sensor, which monitors the helium pressure to detect any increase from the initial atmospheric level—any pressure change indicates a leak in the part. Helium accumulation air leak testing offers good sensitivity (down to 10-3 mbar l/s, depending on enclosure size), high reliability, and good repeatability, and is not susceptible to temperature.
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    Nitrogen Purge Testing
     
  • CTS’ patented nitrogen purge testing instrument is a localized, sniffer-style tester with superior background control that reduces the chances of false leak failures. Utilizing low pressure nitrogen, the system creates a helium-free environment for the mass spectrometer gas analyzer to sample and detect micro-leaks. Our nitrogen purge testing technology can detect leaks as low as 10-6 scc/s.
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    Hard Vacuum Testing
     
  • In hard vacuum leak testing, a part or vessel is placed inside a sealed chamber. A vacuum pump removes all the atmosphere from the chamber and the part; the part is then filled with tracer gas, such as helium. The mass spectrometer then samples the air inside the test chamber for tracer gas escaping the part. Vacuum testing is extremely sensitive (down to 10-8 scc/s), highly repeatable, and provides reliable and quantifiable results. It can be fully automated and integrated into a production line for fast throughput. This is, however, perhaps the most expensive air leak testing method available.
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    pressure Testing Equipment:
     
  • Pressure gauges [1.5 to 4.0 times of test pressure]
  • Water tanks
  • Potable tanks
  • umps for water filling and pressure
  • Pressure gauges and temperature recorder
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    pressure Testing services
     
  • Pipeline Pressure testing
  • hydraulic pressure testing
  • Oil Leak testing
  • Pneumatic Pressure Testing
  • air Leak testing
  • Hydro Static Pressure Testing
  • Oil Leak testing
  • Api spec 6a pr1 Testing
  • Api spec 6a pr2 Testing
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    Pipeline Pressure Testing Services
     
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