What is leak testing equipment?
Leak testing equipment verifies that a sealed part, such as a housing, fluid circuit, medical device or battery pack, does not leak beyond a specified rate. Production leak testers use pressurized or evacuated air, measure the resulting pressure change or flow, and give a fast pass/fail result with data for traceability.
Flow testing is the counterpart. Instead of proving a part holds pressure, it confirms that intended passages such as orifices, nozzles, filters and tubing pass the right amount of flow. Many plants run both on the same instrument platform.
How leak and flow testing methods work
A typical air test cycle runs in four phases: fill the part to test pressure, stabilize while temperature and part stretch settle, measure, and exhaust. The measurement phase differs by method:
- Absolute pressure decay: A transducer watches the isolated part’s pressure fall. Leak rate is calculated from pressure drop, internal volume and test time.
- Differential pressure decay: A differential transducer compares the part with a leak-tight reference volume, resolving smaller changes at higher test pressures.
- Mass flow: The part stays connected to regulated supply pressure, and a flow sensor measures make-up flow, which equals the leak rate.
- Flow testing: Air flows through an intended path, and the tester checks that flow or pressure falls within limits.
- Helium tracer gas: The part is charged with helium, and a mass spectrometer detects helium escaping in a vacuum chamber, accumulation chamber or at a sniffer probe.
| Method | What it measures | Best for | Limitation |
|---|---|---|---|
| Absolute pressure decay | Pressure drop over time | Small to medium volumes, simple setup | Resolution falls at high pressure and large volume |
| Differential pressure decay | Difference from reference volume | Tighter limits on small and medium parts | Needs matched reference volume |
| Mass flow | Make-up flow at test pressure | Large volumes such as battery packs and tanks | Longer fill on big parts |
| Flow test | Flow through intended path | Orifices, nozzles, filters, tubing | Not a leak test |
| Helium tracer | Helium escaping the part | Very low leak rates, hermetic parts | Higher cost and cycle complexity |
Physics sets the practical limits. By the gas law, a small temperature change in the part or test air changes pressure just like a leak does. That is why stabilization time, part temperature control and good fixture design matter as much as the instrument.
Common applications
- Automotive and EV manufacturing: die-cast housings, cylinder heads, fuel and fluid circuits, battery packs, trays and cooling plates at plants across Alabama, Georgia, South Carolina and Tennessee.
- Medical devices: tubing sets, connectors, bags and molded disposables in cleanroom assembly.
- HVAC and appliances: refrigeration circuits and water-carrying components.
- Hydraulics and gas components: valves, fittings and regulators.
- Aerospace: fluid and pneumatic components.
- Electronics: sealed enclosures with IP ratings.
Choosing the right leak testing equipment
The best leak test starts with a meaningful specification. “No leaks” is not testable, but a leak rate at a stated pressure is. From there, part volume and required sensitivity point to pressure decay, mass flow or helium, and cycle time narrows the choice further. Expect the fixture, seals and part temperature to decide whether the test is repeatable. Qualify the test with known good parts and calibrated leaks before production, then verify it daily.
Manufacturers we represent for leak testing
Tecna Marposs has built air leak and flow testers in Mirandola, Italy, since 1983 and has been part of the Marposs Group since 2016. Its Provaset T3L instruments cover absolute and differential pressure decay, flow and mass flow testing. The compact T2 and rugged 2SEAL suit bench stations, and TM3 modules bring up to sixteen channels to automated lines. LTC and Leak Master tools verify testers in production, and the wider Marposs group adds helium tracer gas systems and turnkey test machines, with US support from Marposs Corp. in Auburn Hills, Michigan.
Get local application support
Our engineers work with automotive, medical and industrial manufacturers on test method selection, fixture design and trials with Marposs. Visit engineering support, request a quote, or find your area manager on the territories page.
