High Pressure Gas Generation and Gas Processing Unit (HPGU)
and Leak Test Modules (LTM)
System Configurations with Key Features
High Pressure Gas Generation and Storage
The high pressure gas generation and gas process components are housed within two purpose-built ISO standardised shipping containers for easy logistical and installation purposes.
The high pressure gas unit (HPGU) is designed for pressurising hydrogen fuel tanks to 700bar (or 875Barg for one off tests) using forming gas, 5% hydrogen and 95% nitrogen, to then be able to perform a leak test within the leak test module (LTM).
Once the test cycle is completed, the pressurised forming gas is then stored at low pressure, around 10barg before being compressed and stored at 330barg.
Some of this 330barg forming gas is compressed and stored at 1000Barg, then used to fill the hydrogen fuel tanks within the two leak testing modules.
High Pressure Gas Processing
The hydrogen fuel tanks are filled from the two 330barg storage to an intermediary pressure, then the fuel tanks are finished being filled from the 1000barg storage to raise the pressure to the specified test pressure.
Once the test cycle is completed within the leak test module the forming gas inside the hydrogen fuel tank is evacuated via the defueling panel. The system reuses the forming gas time and time again released from the fuel tank down to 30Barg of pressure with the remainder vented to atmosphere.
Leak test Modules
Housed in a purpose-built safety interlocked room, the two leak test modules test the leak tightness of the hydrogen fuel tank, whilst filled with high pressure forming gas.
The hydrogen fuel tank is firstly loaded onto a gas test fixture (GTF), which positions and secures the fuel tank ready for being fed into the loading conveyor, then the bridging conveyor into the leak test chamber.
The fuel tanks are automatically barcode scanned as they pass over the bridging conveyor before being loaded into the vacuum chamber. When a fuel tank enters the chamber, pins are actuated to lock the GTF into position before an automatic coupling connects the GTF to the rest of the system.
Each of the gas test fixtures can hold up to four hydrogen fuel tanks at once for testing. The test chamber is then closed, and air is evacuated, creating a vacuum. The fuel tanks are also evacuated but a difference between its pressure and the test chamber pressure is first created to carry out a gross leak test. If this is passed successfully then the fuel tanks are completely evacuated and subsequently backfilled with forming gas and quickly pressurised.
Once the gross leak test is completed the fuel tank is fuelled with the forming gas before being held at pressure to undergo the pre-determined test cycle. Once the test cycle is completed the forming gas is recovered from the hydrogen fuel tanks and returned to the HPGU and stored at pressure for reuse.
A preliminary test is also included as part of the overall test cycle, by feeding an amount of nitrogen into the test chamber whilst there’s no hydrogen fuel tank present. This test ensures the mass spectrometer is working as intended and calibrated to the correct range. This test uses low pressure gas from the high pressure generation unit.
The two leak test modules are housed within a safety interlocked test room.