Permanent core plumbing product

摘要

A plumbing part is made from a permanent core and a body cast around the core. The core is formed of a material which meets the retirements as to the permitted leachability of lead and/or other undesirable materials from the core into water flowing through it. The core material has a melting point preferably at least 200 DEG F. above that of the cast body. The core also has a coefficient of expansion which is equal to or less than that of the material fuming the cast body.