Steam condensing apparatus with freeze-protected vent condenser

摘要

A two-stage steam condenser (70) prevents freezing from occurring in its tube rows (80,102) by continual purging of the tube rows. Such continual purging prevents any steam from back-flowing into a tube row (80,102) thereby eliminating the possibility that condensate or noncondensable gases will become trapped therein. This is achieved by isolating each of the tube rows (102) in the second stage (92) of the condenser (70) so that the pressure of one tube row is not exposed to the pressure occurring in another adjacent tube row. The condensate collected in the various tube rows (102) of this second stage (92) is delivered to a common drain pot (114) that is hydraulically balanced to accommodate the various pressures in these tube rows (102). Such hydraulic balancing also prevents any back-flowing from occurring from one tube row (102) into another. Furthermore, in this second stage (92) of the steam condenser (70), the steam (88) and resulting condensate both flow concurrently downward while any noncondensable gases (94) are vented counter-currently upward against such steam and condensate flow.