Abstract: A chimney having a tubular inner liner and a tubular outer wall is provided with a seal for sealingly closing the upper end of the space between the liner and outer wall notwithstanding the radial and longitudinal displacement between the liner and outer wall. The seal includes a plurality of slidingly engageable seal elements which permit such relative movement between the liner and outer wall while maintaining an effective seal therebetween at all times. One of the seal elements may be fixedly mounted to one of the liner or outer wall and the other of the seal elements may be movably associated with the other of the liner and outer wall. An annular rain hood is provided above the seal in the illustrated embodiment. In one form, the seal is disposed in overlying relationship to the space between the liner and outer wall and in another embodiment, the seal is disposed radially outwardly thereof.

Abstract: A framework structure defined by a first plurality of tetrahedral elements laterally juxtaposed in a first array and a second plurality of tetrahedral elements laterally juxtaposed in a second array, with the projecting apices of the first array received in the spaces between the projections of the second array and the projecting apices of the second array received in the spaces between the projections of the first array. In the illustrated embodiment, the bases of the tetrahedral elements of the first array define a common plane and the bases of the tetrahedral elements of the second array define a common plane extending parallel to the plane of the first array bases. The tetrahedral elements in the illustrated embodiment are formed of edge elements and corner connectors. The corner connectors are secured in interconnected association and, in the illustrated embodiment, the corner connectors are secured by connecting plates.

Abstract: An equilateral derrick structure such as for use in erecting chimneys and the like, wherein a plurality of horizontal members, upright diagonal brace members, and vertical column members are interconnected by a plurality of connectors to provide a desired three-dimensional framework derrick. The horizontal members may define a first kind of structural element, the brace members may define a second kind of structural element differing from the first kind, and the column members may define a third kind of structural element differing from each of the first and second kinds. The connectors may be formed as unitary members having a center portion defining a right circularly cylindrical hole for receiving corresponding right circularly cylindrical column members. The connectors may further define outwardly projecting flanges for connection of the horizontal members and diagonal brace members thereto.