Test Application from TQC
Leak Testing of Plastic Fuel Tanks
TQC has specialised in the automatic helium leak testing
of components for many years. Fuel tanks have previously been regarded
as a leak testing problem - the volume is unstable and too large
for air decay testing. Water dunk testing is operator dependent
and causes longer term damage to the unpainted tank. Neither method
will detect a fine vapour leak.
Now proven by several installations, TQC is able to
supply Fuel Tank Leak Testing using Helium. The system provides
a fast reliable dry test with numerical leak results. The sensitivity
is equivalent to a "dunk tank bubble" once in several
days. Connections to the tank are made automatically, the system
is self-monitoring and the operator may be unskilled. The system
is suitable for leak testing metal or plastic tanks.
- Quantifiable leak testing
- Calibration to British Standards
- Fast, clean and dry test
- High sensitivity
- Automated pass/fail limits
- No drying costs and no tank water damage
Typical specification for a 75 litre plastic fuel
||48 second cycle (twin station unit)
|Pass / fail limit
||10-4 mbarl/sec (0.1mm3/sec)
||approx 8000 tanks/standard cylinder
Tank Testing using Helium
chamber and tank
2. Dose tank when chamber reaches 0.1mbar
3. Enter measure phase
4. Evacuate helium from tank. Vent chamber
5. Vent tank and chamber
6. Test complete
- The fuel tank is placed in a supporting cradle which slides
into a stainless steel chamber.
- Operator controls close a safety shielded chamber door.
- The sequence is automatically started by the door closure.
- The chamber and tank are pumped down together to a pressure
of 180mbar, at which point the tank is isolated from the chamber.
- The chamber pressure is further reduced to less than 0.1 mbar,
during which time the tank pressure is monitored to check for
a gross leak.
- A 10% concentration of helium is dosed into the tank, allowed
to disperse, and the chamber is sampled for leakage using a mass
- After the test, the helium is evacuated, the chamber and tank
are vented together to atmosphere, and the door is opened automatically.
Results are then logged for SPC analysis.
Fuel Systems Legislation:
Total vehicle and component assemblies are subject to a variety
of fuel loss legislation requirements. Both US and EC evaporative
emmissions requirements are the subject of continued revision and
it is advised that the current USA Californian certification standard
be adopted as the basis for vehicle component and assembly production
If you have a current project that you are
already looking at, or you are considering improvements to your
production in the near future, call us and we will be happy to offer
our professional advice & visit you at your site.