Abstract: A dual cartridge seal includes first and second rotary seals each formed by a stationary sealing ring and a rotatable sealing ring and a sleeve, fitted to be co-rotatable with a rotatable shaft to be sealed. The rotatable sealing rings are mounted on the sleeve. The stationary sealing rings are mounted so as to be radially spaced from the sleeve so that the stationary sealing rings and a portion of the sleeve define a barrier fluid chamber. The barrier fluid chamber has an inner wall defined by the portion of the sleeve, and an outer wall defined by the inner surface of the stationary sealing rings or ring holders. In order to promote barrier fluid circulation within the barrier fluid chamber, and thereby to more effectively remove heat from the regions of the rotary seals, the inner wall and the outer radial wall are oriented so that at least one of those walls is non-parallel to the rotational axis of the shaft.