| 摘要 |
A heat recovery steam generator (HRSG) (A) has a casing (2) and several heat exchangers in the casing. Some of those heat exchangers (12,16) take the form of coils (18) having multiple lower headers (36) into which the lower ends of tubes (18) open. The tubes (18) and headers (36) hold or may hold water and need to be drained from time to time. To this end, the heat exchanger (12,16) has a drain system (20) provided with drain pipes (40) that are connected to the lower headers (36) and contain check valves (48) that permit the water to flow away from the headers (36), but not into them. The drain pipes (40) lead to and open into a drain manifold (46). The drain pipes (40), check valves (48) and drain manifold (46) are assembled in a shop along with the coil (18) and, when the HRSG (A) is assembled in the field, lie within the interior of the casing (2). The drain system (20) also includes a single common drain line (52) that extends downwardly from the drain manifold (46) and through the floor (8) of the casing (2), beyond which it is provided with a drain valve (56) that, when opened, allows water to drain from the coil (18). |
