Patent ID: 7364131

Claim:
A non-return valve for use in a flow channel of a metal molding system, the non-return valve comprising: a tip member; a ring member configured to be slidably arranged around a portion of the tip member for a travel between an open and a closed position the tip member and the ring member being configured to cooperate with a flange member for limiting the travel of the ring member; a melt passageway being configurable along the non-return valve when the ring member is arranged in an open position, the melt passageway including: a complementary pair of spigot portions that are configured along any combination of: i) the tip member, (ii) the ring member, and (iii) the flange member, the complementary pair of spigot portions being configured to cooperate in a substantially closely-spaced, overlapping, and parallel arrangement when the ring member is arranged in the closed position to provide a spigot-seal to substantially block a backflow of a metallic melt through the non-return valve, the spigot-seal maintaining an effective backflow restriction even in an eventuality of transient movement between the complementary pair of spigot portions during injection of the metallic melt; and a pair of complementary retaining-sealing portions being configured on parallel faces provided on the rear of the ring member and the front of the flange member, whereby a face-seal is configurable therebetween when the non-return valve is in the closed position to assist in blocking the backflow of melt flow through the melt passageway, wherein: the tip member includes a spigot flange, the complementary pair of spigot portions are configured along a portion of an outer circumferential surface of the spigot flange, and along a portion of an inner circumferential surface of the ring member, and the melt passageway further includes: a transfer portion disposed on an inner surface of the ring member.