Thermal shock minimising arrangement in steam plant - uses continuous forward or reverse circulating flow through idle line and pump

摘要

The arrangement for minimising thermal shocks in the high pressure sections of steam generating plant is for plant with feed pumps in parallel (8-10). Water from the min. safe flow lines (35, 35, 36) bypassing the main feed checks (17-19) is returned to the main lines (11-13) immediately downstream of the feed control assembly (14-22) and lines of similar capacity (46-48) embodying shutoff valves (49-51) and depressurisers (52-54) run from the ends of the feed lines back to the tank (1). Also there are reverse flow heating lines (61-63) with shutoff valves (64-66) and depressurisers (67-69) bypassing the NRVs (14-16; 40-42) in the other lines.