There is growing pressure around the world to reduce the environmental impact of transport. Hydrogen is paving the way for an era of sustainable, carbon-neutral or even carbon-free mobility in the short and long term. The growing demand for these zero-emission engines is currently and primarily focused on commercial vehicles. In Switzerland, for example, the "H2 Mobility Initiative", in collaboration with a major car manufacturer, aims to introduce 1,600 hydrogen trucks on the roads by 2025.
This type of hydrogen vehicle stores the gas in high-pressure tanks, about 700 bar. This compression makes it particularly necessary to strengthen the tanks and therefore makes their cost and weight high. The pressure in the tanks must be monitored and it is imperative that they have reliable and certified pressure measuring instruments to work with hydrogen. Hydrogen atoms are extremely small and, due to this property, can even penetrate solid materials through a process known as permeation. Over time, pressure transmitters stop working because of this process.
For this type of application, high-performance, high-precision pressure transmitters are required to monitor vehicle tanks reliably and safely. A wide temperature range should also be covered, as strong temperature fluctuations can occur in hydrogen tanks. Therefore, the main factors to consider when choosing a pressure transmitter for hydrogen tanks should not be overlooked:
- Pressure range: Lower pressure increases the life of the sensor.
- Temperature: The flow of gas through the sensor membrane increases at higher temperatures, so it is important to consider the type of material to be used for the parts in contact with the fluid.
- Membrane thickness: the gas flow is inversely proportional to the thickness of the membrane. The thickness of the membrane can also significantly double the life of the sensor.
- Membrane surface: the gas flow is directly proportional to the membrane surface.
Wika offers as a solution for such applications the MH-3-HY pressure transmitter: a pressure sensor specially developed for use in vehicles equipped with hydrogen fuel cells, with high shock and vibration resistance. Thanks to the hermetically welded thin film measuring cell, additional sealing materials are not required. Unlike other sensor technologies on the market, the measuring cell does not have an oil filling.
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