APPLICATION NOTE: Hydrogen H2-ready pressure and temperature sensors from Variohm EuroSensor

As the market for innovation in hydrogen fuel generation develops in line with the growing need for low carbon energy, the leading sensor specialist Variohm EuroSensor offers a range of pressure and temperature sensors that fulfil safe measurement and monitoring of hydrogen processing, storage, and transportation systems. With pressure ranges from 1.0 bar to 1000 bar, both the EPT31H2 and SMO31H2 series pressure sensors have EC79/2009 and EC406/2010 type-approvals for hydrogen processing and storage systems whilst the SMO31H2 also has European E1 automotive type-approval to comply with the required standard for mobile pressure monitoring applications on transportation vehicles. Furthermore, the SMO31H2 is designed to meet requirements for use in PL:d/SIL2 systems. These H2-ready pressure sensors are complemented with Variohm’s ETP21H2 series temperature sensors – specifically designed for hydrogen processing tasks where aggressive, pressurised gas or liquid media requires accurate and reliable temperature measurement.

All EPT31H2, SMO31H2 and SMO31-Pl:d series pressure sensors feature high-grade 316L stainless-steel wetted parts for extreme resistance to hydrogen embrittlement and permeation with IP67 protection as standard and IP69K optionally available. Internally, a piezo resistive sensing element coupled with the latest ASIC circuitry assures excellent accuracy and high resistance to shock and vibration across an operational temperature range of up to 125°C. Several pressure range options from 1.0 bar to 1000 bar are available for gauge or vacuum measurement (EC79 approval is limited to 700 bar for all model lines). A choice of four pressure ports include ¼ NPT, M16x1 Male, 7/16“- 20 UNF 2A Male, and 3/8“-24 UNF2A. Further application flexibility is ensured with optional 600 mm cable connection, M12x1 round connector or Packard Metri-Pack connector. All sensors feature a 4 – 20 mA output from a 10 – 32 VDC supply voltage whilst the EPT31H2 also includes a 0.5…4.5V ratiometric output from a 5V DC supply. With room temperature accuracy specified at less than 0.5% of range, the sensors are rated for more than 10 million pressure cycles.

Variohm’s ETP21H2 hydrogen temperature sensor is built to the same exacting quality as the H2 pressure series with its stainless-steel housing protecting a PT100 sensor element that has a measurement accuracy to greater than +/- 1.0 % at RT. A choice of output options cover 10…32 VDC for 4…20 mA, or 5 VDC for ratiometric 0.5…4.5 V, and the same electrical connection options as their pressure sensing counterparts ensure straightforward installation where required.

Specifically targeting hydrogen powered fuel cell applications on mobile vehicles, the sensor’s low current consumption of just 7.5 mA will suit battery powered use. A working temperature range from -40 to +125 °C enables wide application flexibility whilst short-circuit and reverse voltage protection provides security.

Variohm EuroSensor’s hydrogen process pressure and temperature sensors are based on wellproven sensor design technologies developed over several year’s extensive use and application success in demanding automotive, agricultural, construction and industrial measurement tasks. They have been specially adapted and certified where appropriate for precise measurement tasks across hydrogen production, processing, storage, and distribution logistics.

Further information is available for download at www.variohm.com.