Electricity and Control March 2024

MEASUREMENT + INSTRUMENTATION : PRODUCTS + SERVICES

The gold standard in pressure sensors for H 2 applications

Hydrogen holds considerable promise as a future energy fuel and as the development market grows, demand for suitable measurement instrumentation is growing too. KELLER, with its home base in Switzerland and represented lo cally by Instrotech, manufactures isolated piezoresistive pressure sensors for the type of pressure measurements first conceived by KELLER founder Hannes W Keller. The great advantage of the pie zoresistive measuring principle is its stability. The chip that measures the pressure is installed in an oil-filled cylinder, sealed by a steel di aphragm. This ensures optimum isolation from the medium in which it is operating. The piezoresistive pressure sensor is also considered one of the most stable for hydrogen applications. Without additional actions, however, an oil-filled sensor can also present a disadvantage. Under certain circumstances, and at high temperatures, hydrogen mole cules can split into two hydrogen atoms. These atoms are smaller than the pores of the steel membrane, which means the atoms can penetrate through the membrane into the oil chamber of the pres sure sensor. In the oil chamber, they fuse again to form a hydrogen gas molecule (H 2 ), which leads to offset errors – or signal devia tions of the target value – due to the expansion. This phenomenon is called ‘permeation’. For this reason, KELLER uses gold-plated steel membranes for hydrogen pressure sensors. Gold has much smaller pores than stainless steel. The hydrogen can hardly penetrate the gold layer. This action, together with fully welded sensors without internal seals, confirms KELLER’s competence and strength in the pressure sen sor market, including for hydrogen applications. The typical pres sure ranges for applications with hydrogen are from 0...2 bar to 0...1 000 bar. KELLER offers suitable sensors for these applications. In addition, the hydrogen pressure sensors are compatible with the EC79 standard for automotive applications.

For more information visit www.instrotech.co.za

KELLER’s gold-plated OEM pressure sensors are designed for hydrogen applications.

MARCH 2024 Electricity + Control

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