Convection recuperators of the channel recuperator type or hairpin coil type are manufactured of steel tubes whereby the heat absorbing gas usually flows through the tubes and the heat transferring gas around the tubes.

Channel type recuperators to preheat gas at low pressure are often installed in a rectangular channel and consist of tube bundles which are connected downstream of one another on the flue gas side.

The convection recuperator of the hairpin construction type is mainly used when the pressure of the gas to be preheated is elevated; the heating surface of this construction type consists of several tubes bent to form hairpin coils which are arranged in parallel. The tubes are welded to the inlet and outlet headers.

Convection bank for an Iron Direct Reduction Plant with channel type recuperators and hairpin coils