GB680592A - Improvements in rotary regenerative air preheaters - Google Patents

Abstract

680,592. Rotary regenerative heat-exchangers. AKTIEBOLAGET LJUNGSTROMS ANGTURBIN. Sept. 25, 1950 [Oct. 8, 1949], No. 23422/50. Class 64 (i) In a rotary regenerative air preheater the rotor is divided by a circular partition 29 into inner and outer sections 25, 26 in which the heat transfer material 16 is carried, and the housing 10 of the preheater includes at one end thereof at one side of the rotor axis, inlet and outlet ducts 22, 31, communciating one with the inner and the other with the outer sections of said rotor for a gaseous medium (e.g. hot gases) to flow in series through said rotor sections by way of a chamber 24 located at the other end of the housing, a by-pass duct 40 and dampers 41 and 42, located respectively in the duct 22 leading to said outer section and in said by-pass duct, being provided to apportion the flow of the gaseous medium through the by-pass duct for maintaining the heat transfer material in the inner section at a predetermined temperature (e.g. at a temperature above the dew point of the hot gases). In the form shown provision is made also to by-pass the outer section 26 of the rotor on the air side of the regenerator. Air to be heated flows from the inlet duct 34 through the inner section 25 of the rotor to a chamber 33 and thence through the outer section 26 of the rotor, to a chamber 36, a portion of the heated air being led from the chamber 36 through ducts 37 and the remainder constituting primary air being directed to the primary air duct 38. Dampers 46, 47 enable the primary air from the chamber 33 to by-pass the outer section 26 of the rotor and to flow directly to the primary air outlet duct 38 through a by-pass duct 45 so that the heat transfer material in the outer section 26 of the rotor is not exposed to large volumes of relatively cool air at low boiler loads. At the same time, the outer section 26 of the rotor is being by-passed by the boiler gases, the damper 41 being closed and the damper 42 being opened so that a larger volume of gas may flow over the inner rotor section 25. The duct 45 also enables highly heated air to be mixed with relatively cool air in the primary air duct 38 so that tempering of the primary air stream may be effected. Co-operating sealing strips are provided respectively on the upper edge of the partition 29 and the adjacent portion of the rotor housing 10 Fig. 3 (not shown).