High temperature seal

Claim 1

In a closure assembly including a closure member and rim surrounding an opening with the closure member being adapted to close on the rim by movement along a predetermined path toward the rim and the closure member and rim including hard metal heat expandable rings adapted to engage in seating relationship with each other characterized in that: (a) the ring on the closure member has a seating surface facing toward the rim along said predetermined path for seating engagement with the ring on the rim; (b) the ring on the rim has a seating surface against which the seating surface on the ring on the closure member seats as the closure member is moved along said path toward the rim; (c) the rim includes an axially extending inner annular wall which defines at least a portion of the opening, the rim further including a heat expandable annular shoulder of material having a greater coefficient of expansion than that of the ring on the rim, and said shoulder being formed to define a radially inwardly facing conical surface extending continuously to said inner annular wall; (d) the ring on the rim has a radially outwardly facing conical surface mating with and restrained against movement and in abutting relation on the conical surface of the shoulder when the ring on the rim and the shoulder are at the same temperature so that as the shoulder expands radially circumferentially outwardly upon heating, the ring on the rim is permitted to move parallel to said predetermined path and down the conical surface of the shoulder, so as to remain bedded thereon; and wherein (e) the rim includes a clamp for holding down the ring on the rim against movement along said path away from said shoulder.