FEEDWATER HEATER Russian patent published in 1997 - IPC

FIELD: regenerative heating of steam turbines. SUBSTANCE: uptake tube platens 6 installed in casing 1 are connected through bottom and top ends of their tubes to bottom and top chambers 8 and 9 of central header, respectively. Intertube space of platens 6 communicates with pipe 2 supplying heating steam through shaped duct 13 accommodating downcomer tube platens 7 connected through their top ends to chamber 9 which houses partition formed by repair manhole 14 and removable cover 15. Partition is installed below top ends of tubes. Throttling hole 16 is provided in manhole 14 and/or cover 15. Downcomer tube platens 7 are connected through their bottom ends to chamber 9 below partition and/or at least to one tube header 19 communicating with additional feedwater outlet pipe 18. Shaped duct 13 may hold additional tube plates 19 placed between steam supply piping 2 and downcomer tube platens 7 and connected through tube headers 20, 21 to pipes 22 and 23 for, respectively, inlet and outlet of feedwater. As viewed on heater top, update, downcomer, and additional tube platens 6, 7, and 19, respectively, are arranged about central header in involute manner. In other design form, uptake tube platens 6 are arranged in casing about central header in radial planes and downcomer ones 7 and additional tube platens have their central parts placed in parallel vertical planes. Outlet ends of tubes 6 and 7 are spaced apart which has reduced thermal stress in central header. Additional tube platens 19 communicate through tube headers 20,21 with additional feedwater stream to reduce additional thermal stress and mass of heater. EFFECT: reduced thermal stress and mass of heater, optimized pressure drop distribution through intertube apace and improved augmentation of heat transfer in steam cooling zone. 5 cl, 6 dwg