Plastic ball valve manufacture for use as e.g. gas stop valve, produces material bond between inner section and outer casing, by melt injection welding, precluding all possibility of through-leakage between these parts

摘要

External shape of the insert (6) and adjacent internal form of the casing (1) are pressure injection molded. Plastic initially used to mold the insert is then injected, to weld together molding and insert. The ball (3), bearing rings (4), ring seals (5), bearing bush (8) and inlay are mounted together with the molded inner section. The mounted internal section is injected with plastic, forming a welded bond between them. An Independent claim is included for the corresponding valve. Preferred features: An adhesion copolymer thermoplastic forms the molding. The bond between inner section and casing (outer section) is at least partially materially-interlocking. There are penetrations (6a) in the insert (6) and molding, providing additional anchoring points for interlocked bonding.