GB744103A - Apparatus for preheating air in stages, more particulary for steam boilers - Google Patents

Abstract

744,103. Air preheaters; feedwater heaters. STEINMULLER GES., L. & C. Sept. 16, 1953 [Oct. 7, 1952], No. 25581/53. Class 64(1). In an air preheater in which the air is heated in a plurality of regenerative stages, a recuperative heat-exchanger is interposed in the air stream between successive regenerative heating stages. The arrangement preferably comprises two axially spaced regenerative rotors 1, 2, heating gas flowing through the apparatus from an inlet 3 to an outlet 5 whilst air to be heated enters the apparatus through a blower 6, the heated air leaving the apparatus through a duct 8. Interposed between the regenerative rotors 1, 2 in the air stream is a recuperative heat-exchanger 7 through which superheated steam is passed, thus adding further heat to the air between the regenerative heating stages. The flow of steam passing through the heatexchanger 7 may be controlled through aby-pass. A portion of the air may be drawn off after initial heating in the rotor 2 if e.g. a supply of air at a relatively lower temperature is required. Interposed between the rotors 1, 2 in the stream of heating gas is a heat-exchanger 4 which may be a feed-water heater or a steam generator. Heating gas or air may be added or drawn off between successive stages and a controlled quantity of the heating gas may be caused to by-pass the heat-exchanger 4 if necessary. The regenerative heat-exchangers 1, 2 may be of the stationary-matrix type.