| 摘要 |
1,195,260. Forced flow steam boilers. COMBUSTION ENG. Inc. 13 Nov., 1967 [12 Dec., 1966], No. 51632/67. Heading F4A. During start-up of a forced through-flow boiler with partial recirculation, throttle valves BT, BE are closed and the increase in volume of the heated working fluid is relieved through a by-pass 44 leading from a point between the feedwater heater 28 and economizer 30 to a point, such as the deaerator 26, in the low pressure part of the feed circuit. Throttle valves 46 and throttling orifices or capillary devices 48 are arranged so that the pressure drop thereacross does not produce flashing until the fluid reaches the deaerator 26. One valve 46 may be controlled by the passage at the inlet to economizer 30. At a later stage of start-up, the valve BE is opened to allow the fluid from the evaporator 32 to flow to a separator 36, the water from which is returned to condenser 20 whilst the steam flows through pipe 37 to the superheater 34. In Fig. 2 the high pressure feed pump 18 is provided with a return by-pass 54 leading back to deaerator 26 and the pipe 58 relieving the excess fluid during start-up is connected to the by-pass 54. |
