Speaker
Description
Industrial valves for cryogenic application are typically made of austenitic stainless steel. A new design has been developed, where stem and extended bonnet are made of glass fiber reinforced PEEK (PEEK/GF). This material has a significant lower heat conductivity and lower specific weight. Therefore valves with minimized heat input as well as very compact and lightweight valves can be realised.
The results of measurements of the permeation behaviour of virginal composite as well as composite with permeation barrier are shown. Further measurement results of the rate of heat flow of composite samples and the whole valve assembly have been performed. The novel valve design will be introduced.
The laminate structure has been designed by herone GmbH to withstand the mechanical load due to system pressure and valve actuation. The wall thickness is slightly higher than valve made of stainless steel. Test specimen have been made to perform measurements on thermal conductivity und permeation.
The permeation rate of PEEK/GF is very high compared to stainless steel, this can cause problems in later applications. Therefore test specimen with interlaminar metal foil have been investigated. Metal foils made of stainless steel with a thickness of 10 µm already decreased the permeation rate of about two orders of magnitude compared to natural PEEK/GF (see Figure 1, right side). Foils with a thickness up to 100 µm have been investigated.
