Abstract: An improved, wholly mechanical, valve unit is provided to automatically allow for flow between a high temperature liquid line and a cooler temperature liquid line in order to maintain the immediate availability of hot liquid immediately upstream of the valve, especially for hot water used in a building. The valve unit of the present invention includes a thermally-activated, bi-metal, or more broadly bi-flexive, valve disc, and a smaller diameter valve seat that concentrically contacts the valve disc intermediate the outer circumference and the center of the disc. The bi-flexive disc is provided two-sided, circumferential support, thus substantially equalizing the pressure against both sides of the disc, even when in the closed valve position between the higher temperature, higher pressure, hot water line and the lower pressure cold water line. The valve opens when the temperature differential across the valve disc decreases below a preset amount.

Abstract: An improved, wholly mechanical, valve unit is provided to automatically allow for flow between a high temperature liquid line and a cooler temperature liquid line in order to maintain the immediate availability of hot liquid immediately upstream of the valve, especially for hot water used in a building. The valve unit of the present invention includes a thermally-activated, bi-metal, or more broadly bi-flexive, valve disc, and a smaller diameter valve seat that concentrically contacts the valve disc intermediate the outer circumference and the center of the disc. The bi-flexive disc is provided two-sided, circumferential support, thus substantially equalizing the pressure against both sides of the disc, even when in the closed valve position between the higher temperature, higher pressure, hot water line and the lower pressure cold water line. The valve opens when the temperature differential across the valve disc decreases below a preset amount.

Abstract: A pressure vessel is disclosed which includes a lower metallic dome having a lower rim portion, and an upper metallic dome having an upper rim portion, a plastic liner disposed within the upper and lower metallic domes, a metallic band disposed between the plastic liner and the upper and lower metallic domes proximate the respective rim portions thereof, and an insulating material disposed between the metallic band and the plastic liner, the metallic band and insulating material protecting the plastic liner from elevated temperatures when the upper and lower rim portions of the metallic domes are welded together. A method of fabricating the pressure vessel and a connector for assembling the pressure vessel are also disclosed.