Heat exchanger contg. pairs of coaxial tubes and double tube-plates - which minimise perforation effects and maintain good heat transfer

摘要

A shell-and-tube heat exchanger incorporates pairs of coaxial tubes, the adjacent ends of the tubes being fixed in two tubes plates which are near to one another. The outer surface of the inner tube of a pair is in close contact with the inner surface of the outer tube of the pair. The two tube plates are sepd. by a closed space connected to the atmos. by a fluid outlet orifice. Close contact between the tubes is achieved by pumping a liq. at high press. into the inner tube when they are being assembled. The press is 10-120 megapascal, pref. 70 megapascal. Accidental perforation of a tube by e.g. corrosion does not cause communication between the fluids in the shell and in the tube. The close contact between the tubes maintains good heat transfer, equivalent to that in a homogeneous tube. A leak causing fluid to escape to the atmos. would be detected by an indicator, or visually.