Westinghouse Electric Corporation

King W Chan

Robert M Wilson

Daniel E Ford

Robert L Sylvester

George Bieberbach

Willis B Middlebrooks

Jawahar K Visaria

Gregory V Smith

Randall C Johnson

An improved heat exchanger utilizing a primary heated fluid to vaporize a secondary fluid flowing axially therethrough including a preheater assembly located within a cold leg side of the heat exchanger to allow axial flow of the secondary fluid through a preheater assembly to heat the secondary fluid to it boiling point temperature. The heat exchanger generally comprises a vertical shell portion with a tubesheet disposed adjacent a lower end thereof and a tube bundle which includes a plurality of U-shaped tubes through which the primary fluid flows. The preheater assembly is located in the vicinity of the tubesheet wherein the secondary fluid enters the preheater through a fluid inlet nozzle into a lower feedwater inlet box which is disposed around the inlet nozzle for dispersing the secondary fluid from the nozzle over a greater area. Specifically, the feedwater inlet box may include a double-perforated plate assembly whose flow resistance produces a low velocity uniform introduction of feedwater into the tube bundle. This water flows upward providing axial-counter flow and enhances heat transfer. This cold water is introduced near the coldest end of the tubes where it is most effective, while the design prevents thermal shock of the tubesheet with a layer of warm recirculating water providing a cushion between the tubesheet and the cold feedwater.

Steam generator with axial flow preheater

This patent discloses a secondary fluid supply system for a steam generator used in nuclear reactor power plants. The secondary fluid supply system comprises a secondary fluid (feedwater) inlet nozzle near the base of the steam generator shell, a feedwater riser pipe spaced between the shell of the steam generator and the tube bundle wrapper, the upper end of the feedwater riser pipe being connected to a distribution ring having a plurality of spray nozzles positioned in the recirculating pool above the top of the U-shaped heat exchanger tubes.

Steam generator

A steam generator comprises a distribution means, positioned between the shell and the wrapper in the annular downcomer region of the steam generator, for uniformly mixing the colder feedwater with the warmer recirculating water in the downcomer region of the steam generator so that the colder feedwater is not introduced directly into any steam regions of the steam generator and does not contact any pressure boundaries for preventing water hammer and thermal shock to the steam generator. The distribution means has a downwardly directing means for discharging the substantially evenly distributed feedwater from the distribution means into the downcomer region in a descending direction and away from any pressure boundaries for minimizing flow resistance and for preventing thermal shock to the pressure boundaries. The feedwater and the recirculating water are substantially uniformly mixed in the mixing zone of the downcomer region of the steam generator prior to the mixture of feedwater and recirculating water entering the tube bundle or contacting any pressure boundaries, thereby preventing thermal shock and water hammer to the steam generator.

Steam generator feedwater distribution system

Growing community of inventors

Lutz, FL, United States of America

King W Chan