Hollow glass-fibre reinforced plastic wound articles - made on heated and reducible mandrels

摘要

The mandrel consists of an inner hollow cylinder with an elastic outer hollow envelope and reinforced on the outside with longitudinal steel bands. The outer hollow section is connected bia a space at the shaft to a source of oil, press. pump and heater, and is fed first with cool oil under press. After winding on the GRP to a suitable stage, the oil is replaced by hot oil. To release the winding after curing, the oil press. is dropped. Cure time is thus shortened.