Pressure switch in hydrogen-powered train ensures safety

In a newly developed hydrogen train for local transport, a pressure switch from WIKA plays an essential role. Within the scope of pressure monitoring, it performs the central safety function in the H2 supply system through the journey.
The benefits of hydrogen in rail transport are rather unknown to the general public. Even if the first trains with H2 fuel cells already are in operation. They are powered by non-electrified railway lines and replace the diesel trains which were used before.
Tanks predicated on carbon fibre composite technology
The tank convenience of the hydrogen must be adapted to the distances. Among Actionable ?s customers has specialised in individual fuel storage systems for H2 vehicles. Their cylindrical tanks derive from carbon fibre composite technology. They are therefore extremely robust and yet have a comparatively low weight compared to steel vessels.
Tanks of this type may also be installed in the hydrogen-powered train mentioned at the beginning. This multiple-unit train, designed for commuting traffic, is filled with the hydrogen at a particular terminal. The tank pressure is 300 to 350 bar. While driving, it must be reduced to a single-digit value for the supply to the fuel cell. This is done via a pressure regulation unit downstream of the storage system.
Pressure switch in hydrogen-powered train switches the drive system off
Suitable for use in a new kind of hydrogen-powered train with regard to safety ? the model PXA pressure switch from WIKA.
The pressure switch model PXA meets the requirements of the hydrogen-powered train application. With the monitoring the of tank pressure and pressure regulation in the hydrogen-powered train, the customer uses the pressure switch model PXA for the safety function. The miniature instrument switches off the H2 propulsion system in two cases, according to the function:
if the tank is in danger of emptying
if the pressure becomes too much once the hydrogen is used in the propulsion system
This emergency protection could also be realised with a pressure sensor and a software. But also for trains this solution will be very complicated. It is also rated with a higher risk of error than a switch-based safety function.
SIL-3 approval made the case for its use
The customer didn’t choose the model PXA due to the measurement quality alone. The pressure switch was also considered right for the duty in the hydrogen-powered train due to the SIL-3 suitability. It thus easily meets the safety-related market requirements for the H2 application (SIL-2).
Flameproof enclosure (?Ex d?) and compact design
The PXA has also been designed for ambient temperatures from -40 �C to +85 �C. In addition, the pressure switch has IECEx approval ?Ex d? ( Upbeat ), that your customer requires as standard. An additional benefit of this instrument: The PXA could be easily built-into the storage system thanks to its extremely compact design.
Note
Further information on the subject of hydrogen and on the pressure switch model PXA are available on the WIKA website. For those who have any questions, your contact will gladly gelp you.
Also read our posts
Wika develops pressure sensor for hydrogen-powered vehicles
Hydrogen mobility: Clean engines into the future offer the same convenience as engines today
Turning hydrogen into kilometres
Hydrogen and pressure sensors ? What must be observed?

Leave a Comment