Abstract: A combination of metallurgical and vent engineering design solutions that result in a superior product, lower installed cost, and corrosion-free performance for venting modern fan-assisted gas appliances by using a flexible, compressible, corrugated gas vent connector. Preferably the connector is constructed from a material having a heat conductivity substantially equal to or greater than aluminum. Other forms of the invention include the use of stainless steel; a double wall corrugated wall in the flex section; and the use of flat flex in the corrugated section.By providing the flex connector with twist lock couplings the connector may be assembled in the field more quickly with a greater assurance of its integrity under adverse conditions such as earthquakes or other building moving conditions.

Abstract: A chimney liner system for insertion into a masonry chimney from the top of the chimney down to a stove or fireplace insert. If an offset or a chimney shelf exists in the chimney, a flexible metal pipe member is connected to the bottom end of the chimney liner system. A ceramic heat resistant cloth formed as a sleeve encloses the flexible metal pipe member in selected systems, and in some systems, the sleeve encloses the entire chimney liner system. In some applications, the sleeve may be made from a fiberglass cloth sewn or connected to an inner blanket insulation.

Abstract: A triple wall factory built thermally balanced on demand air flow metal chimney system in which the chimney sections are formed with an insulation chamber filled with insulation material which surrounds the chimney flue and an air passage chamber surrounding the insulation chamber. A negligible amount of cooling air flows upwardly through the air passage chamber during normal operation of the chimney. The air flow is separated from the inner flue by the insulating blanket. This allows the flue to maintain the proper elevated temperatures to resist creosote deposits. During periods of sustained high temperature operation or creosote fire episodes, substantial on demand cooling air flows upwardly through the air passage chamber drawing off heat from the inner flue and the outer wall.