Kautex produces 320 litre hydrogen liner in blow moulding process
Kautex Maschinenbau blow molding consultants have successfully created a high volume polymer coating for extrusion blow molding of H pressure vessels.
The coating has a length of 2 meters, a diameter of approximately 500 mm and a volume of 320 liters. This may be the main occasion when a coating has been created for an H-instrumentation during this blow moulding size.
Hydrogen presents great challenges in terms of the relevance of the porosity of the coating material. As the smallest molecule within the tabular array, H will diffuse through almost all plastics. Specialty polyamides have the simplest barrier properties, however, due to their low softening rigidity and complexity, they need to be previously resistant to be processed on this scale by blow moulding. Newly developed polyamides and a special extrusion technique have now created this potential.
“Producing a coating of this size from a polymer has been a serious challenge. The work we do here is truly pioneering,” says Abdellah El Bouchfrati, Head of Business Development Composites at Kautex, wherever the new H-coating has been developed.
For some time now, Kautex has dedicated its efforts to the continuous development of composite pressure vessels (CPV) for various applications similar to H, CNG and LPG tanks. Composite tanks include a thermoplastic liner, a head half, to which the valve is connected, and a fibre winding that adds mechanical strength. The inner lining is created by blow moulding.
CPV H vessels are typically designed for an associated grade operating pressure of 700 bar and a burst pressure of 1750 bar. The liner can be a central part of the instrumentation. it is the inner skin of the tank. It absorbs the gas, encompassing the contents and sealing it away from the surface. The coating is subject to high mechanical stresses and temperature ranges from -60 °C to +120 °C. Now, for the first time, the strategy developed by Kautex in cooperation with a plastics manufacturer allows H-coatings in sizes with industrial applications to be created by blow molding.
