Removal of suspended sludge from nuclear steam generator

This patent describes a shell and tube heat exchanger, a vertical vessel, tubes within the vessel through which heating fluid passes, means for introducing fluid to be heated to the vessel, a horizontal deck located in the upper portion of the vessel. Equally spaced separating means connected to the deck, opening means in the deck through which heated fluid flows to each of the separating means. A vertical wall means is positioned within the vessel having a circular cross-section, for forming an annular downcomer. The water is separated out in the separating means flowing off the edge of the deck into the downcomer. An opening is in the upper portion of the vessel above the separating means through which steam can be discharged, one of the separating means being completely surrounded by an upright dam, the dam encircling a cross-sectional area at least four times greater than the average area per separating means throughout the rest of the deck so that a quiescent area is created where solids will settle out. A blowdown pipe has an inlet disposed within the dam communicating with the exterior of the vessel for the discharge of such settled solids