Plastic Containers
DESCRIPTION OF TECHNICAL CHALLENGE
Low-cost plastic components cannot be both safely and cost-effectively tested for leaks using
conventional industrial testing methods (such as the underwater bubble test, the pressure drop
method or vacuum leak detection).
Plastic containers are difficult to test with pressure decay methods because the appliedpressure leads to an expansion of the part and can even cause creepage over the testing
period. A reliable measurement is virtually impossible as the pressure in the test part declines.
The reproducibility of the measurement results is difficult to guarantee and continues to declinewith smaller leak rates or increasing volumes.
Stricter emission regulations are also driving the industry standards upwards. Pressure decay
and water bath testing are no longer precise enough for many industrial requirements. Helium
vacuum test methods offer the required sensitivity, but are usually overdesigned for these lowcost plastic components and are simply too costly.

THE INFICON SOLUTION
Today leak detection with helium or hydrogen in an accumulating chamber under normalpressure (accumulation method) is offering an economical solution for leak testing of plasticcontainers.
In a simple chamber, the test part is pressurized with helium orhydrogen through its test gas connection so that the test gas canescape through any leaks into the accumulating chamber. Fansthen ensure an even distribution of the test gas in the chamber – so,independent of the position of the leak, precise measurement values
are guaranteed. The sensor then determines the test gas content inthis atmosphere. The expansion of the test part caused bypressurizing is irrelevant in this measuring system.
Hydrogen can be used just as well as helium. Hydrogen is priced
even lower as a test gas, but does not permit the same sensitivity. In
the T-Guard helium sensor, the highly sensitive, patented Wisetechnology sensor detects an increasing helium concentration. TheSampling Probe AP29ECO does detect the hydrogen share of a
95% nitrogen / 5% hydrogen mixture.

LEAK TESTING OF COMPONENTS
PLASTIC CONTAINERS

EXAMPLES OF PLASTIC CONTAINERS SUITED FOR THIS TESTING METHOD

Servo oilreservoir

Coolant expansiontank~ 10 mbarl/s

10-2 ... 10-1 mbarl/s
1 .. 10 sccm

~ 10 mbarl/s

T-GuardSensistor Sentrac

Sensistor Sentrac
T-Guard

T-GuardSensistor Sentrac

Sensistor Sentrac
T-GuardTank filler cap

Fuel tanksending unit

Swirl pot

Brake fluid
reservoir

Component

Plastic oil tank

Typical leak rate

~ 10 mbarl/s~10 mbarl/s

Recommended
INFICON productT-GuardComponent

Tank filler neck

Typical leak rate
Recommended
INFICON productOil pan-3

Windshiel wiper
fluid container-2-4-2-4-4-2-4-3-4~ 10 mbarl/s~ 10 mbarl/s~ 10 mbarl/s

10 ...10 mbarl/s

10 ...10 mbarl/s

T-Guard
LDS3000

T-GuardProtec P3000(XL)

T-Guard

T-Guard

T-Guard* Click on the product name to get more product information from our website

BENEFITS OF HELIUM / HYDROGEN LEAK TESTING••••-2

Accurate and repeatable measurements for reliable results of leak testing
Test method independent of temperature and moisture
Cost efficient leak testingHigh sensitivity

For more information, please visit us atwww.inficonautomotive.com
T-Guard Helium Accumulation Sensorw w w . i nf i c o n. c o mre a c hus @ i nf i co n. c o m

Due to our continuing program of product improvements, specifications are subject to change without notice.
miaa00en-a (1502)©2015 INFICON