Abstract: A rotary seal seals a large, high temperature rotary drum, such as a rotary cement kiln, from the inflow of ambient air where the drum is mounted for rotation in respect to a stationary hood, the drum having a substantially circularly cylindrical surface at one open end thereof substantially coaxial with the axis of rotation of the drum, and the hood having an opening through which the cylindrical surface extends. The seal is made of a strip of flexible material for encircling the cylindrical surface, the flexible material being substantially air impermeable and resistant to heat and oxidation at temperatures at least up to 250.degree. F. The outer edge of the strip is sealed to the hood. A wear resistant liner is affixed to the underside of the inner edge of the strip to space the strip from the cylindrical surface. The side of the liner opposite the strip mates with the cylindrical surface and is biased thereagainst.