Electra Mining Entrade CS

hydrogen in cryogenic conditions of minus 253 °C up to a transport or gaseous distribution temperature of up to +50 °C.

As a valve manufacturer with wide experience of demanding applications, Quadax® has naturally focussed much attention on the topic of hydrogen. Key challenges include the need to operate valves at high pressures (up to 100 bar) and low storage temperatures (liquid hydrogen at minus 253 °C.) To ensure absolute tightness under such conditions, the company has applied its so-called 4-offset design principle (Figure 1). With this design, the butterfly valve benefits from a circular seat with an equal wall thick-ness all around. Hence the 4-offset design is significantly different from the common 3-offset versions which have an elliptical seat (Figure 1). Actually, dimensional changes in the material caused by high temperature fluctuations act homogenously on the entire sealing surface and thus ensure optimal tightness. This was recently proven in a performance test with helium by an independent testing institute (details available from the authors). What is more, Quadax’s hydrogen valve is equipped with a special seal ring in a special material in order to properly function even at these extremely low temperatures. Since the disc moves smoothly into the seat, wear and tear is significantly reduced. Materials are selected with a nickel content from 10 to 30 per cent. In contact with hydrogen, these alloys show only very little brittleness and the components do not lose any strength. For extreme operating conditions Thanks to the 4-offset design and the latest production technology, the 4-offset valves meet extremely high sealing requirements according to common standards. The track record includes applications at extreme tem-peratures from minus 270 °C to 800 °C. Apart from Linde and Air Liquide, references include notable users in the space sector. Their applications are very demanding with enormous demands placed on quality and safety. The fuels consist of liquid hydrogen plus other chemicals. When producing and storing liquid rocket fuels and also when fuelling the rocket with cryogenic fuel components, which have a temperature under minus 220 °C, reliability and thus safety rank first, because even the smallest leakages can have devastating consequences.