Witt Gas Controls has developed the Ultra 22, a check valve tailored specifically to the requirements of fuel cell systems in industrial trucks. According to the company, the client is an unnamed leading North American manufacturer of fuel cells. This manufacturer required a valve with low pressure drop, leak-free operation, and material compatibility for hydrogen applications. Standard market solutions did not meet the specifications according to Witt.
The focus of the application is on proton exchange membrane fuel cells (PEM), which are intended to replace lead-acid batteries in forklifts, pallet trucks, order pickers, and automated guided vehicles. One advantage: refueling a hydrogen tank takes only about ten seconds according to the manufacturer, while changing a battery is significantly more complex.
Low opening pressures as a technical challenge
The technical challenge lies in the extremely low pressure conditions. Ambient air must flow freely to the fuel cell during operation, but be completely sealed off when idle to prevent unnecessary hydrogen consumption. The opening pressure is comparable to the sound wave of a normal speaking voice – a magnitude at which standard valves often fail.
The Ultra 22 is based on the existing model Ultra 20, but omits the inlet filter to minimize pressure drop. According to the manufacturer, the opening pressure is about 4 mbar (0.058 PSI). An elastomer seal is intended to ensure leak-free operation. The modular system allows for different housing and sealing materials, including aluminum, brass, and stainless steel (1.4305 / AISI 303).
Over 10,000 valves per year
According to Witt, more than 10,000 units are delivered annually to the fuel cell manufacturer. The company, based in Witten, has specialized in gas safety, regulation, and analysis for over 80 years. The author of the underlying technical article, Norm Phelps, is the president of Witt Gas Controls.
