Abstract: Hemispherical dome comprising a plurality of rigid longitudinally extending and radially oriented cells of like size and shape, and arranged in a plurality of circular rows. Each cell is essentially frustopyramidal in shape, having a polygonal cross-sectional shape and tapering slightly in the longitudinal direction from one end to the other. The longitudinal edges of each cell lie along radii of the hemisphere. Each cell is a hollow structure, having side wall means which completely surround an interior air space and which include spaced apart top and bottom walls. It can be formed of a lightweight material, preferably a plastic and especially polycarbonate. The hemispherical dome of this invention provides a lightweight, strong and energy efficient structure which does not require internal supports.

Abstract: A shaped, sacrificial anode for water tanks and a method of constructing the same from extruded sections is disclosed, particularly an anode having a greater mass adjacent to regions of the tank where improved corrosion protection is needed.