Abstract: A closure assembly is provided for sealing vessel manways, coke drums and other high temperature connections. It includes a cover member, a substantially cylindrical retaining member, a crush ring slidable with respect to the retaining member, a stop member, and a sealing ring positioned between an end of the crush ring and the stop member. Tightening screws or bolts pass through the cover member and contact the crush ring. They may be employed for moving the crush ring toward the stop member thereby compressing the sealing ring. The sealing ring may be a graphite ribbon wrapped a number of times about the retaining member.