The Pioneer of Modern Leak Testing

Mass Flow Leak Test

What is a Mass Flow Leak Test?

The mass flow leak test measures the amount of air passing through an object using units of measurement of sccm or
liters/time period. The major advantage of the mass flow technique is that it eliminates the need to know the
volume of the product. There are two mass flow sensing techniques that have found their way in to leak and flow
testing: thermal mass flow and differential sensing mass flow. Differential sensing mass flow, or laminar flow, is
not to be confused with differential mass flow leak testing

How is a Mass Flow test performed?

You will first Chose the preset test – Mass Flow from the test menu on the tester and enter the test pressure into the program.

Next, the product is attached and the test is started. The air moves into the inlet port and the precision micro-thermistor (T1) measures the temperature of the inlet air.

As the test continues, the flow sensor’s heater (H) increases the temperature of the moving air far above room temperature as measured with the sensor T3. Temperature of the outgoing air is measured at the next precision micro-thermistor, T2.

Temperature difference of T2 minus T1 is proportional to the ability of the air mass to transfer heat. The read out is in mass flow units, such as sccm.

Mass Flow Test Pneumatic Diagram

Which Uson testers can perform a Mass Flow Leak Test?

Optima vT – A versatile and customizable leak tester with up to two channels and eight sensor inputs that supports pressure decay, differential pressure, mass flow and other common tests

Qualitek – Fast, sensitive and accurate pressure decay, differential pressure and mass flow leak testers

Sprint – Small foot print single or multi channel pressure decay and flow testers

Vector – Uson’s most powerful and configurable leak and flow tester, fully customizable pneumatics, up to ten independent test channels supporting a wide variety of input sensors

Uson Innovative Systems (UIS) – Custom made manual, semi automatic and fully automatic leak test systems and fixtures

Contact Us


Uson L.P. - Corporate

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Tel: +1-281-671-2000
Fax: +1-281-671-2001


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Shanghai, 200333, China

Main: 021-583 65859, 021-583 59187
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