Heat Exchangers

Heat exchangers are used for heating sludge before its recirculation into anaerobic digesters. The basic heat exchanger is a pair of concentric tubes; sludge flows through the smaller center tube, while water flows (in counterflow) in the annular space formed by the outside of the smaller pipe and the inside of the larger pipe. To increase capacity, a number of these pairs are connected together until their combined size provides the needed capacity. Return bends connect the inner tubes and short sections of pipe connect the outer jackets. Heat exchanger is supplied with supporting steel frame and, as an option, with concentric insulation layer.