| 摘要 |
<p>BOILER WATER TRIP SYSTEM A boiler water trip system comprises a flow transmitter for sensing a flow of water into a boiler, a pressure transmitter for sensing a pressure of steam entering a first stage of a turbine powered by the boiler, a unit power transmitter for sensing the power generated by the turbine, a feeder water temperature transmitter and a drum level transmitter for sensing the level of water in a steam drum connected to the boiler. Function generators are connected to the pressure and unit load transmitters for obtaining a measure of flow out of the boiler. The higher of the two flow values are compared with the feed water flow to the boiler to generate an error signal which is integrated. The integrated error signal corresponds to a calculated boiler water level amount. If the boiler water level rises above or falls below set limits and, simultaneously, a drum level rises above or falls below said amounts as determined by the drum level transmitter, a tripper is activated to trip the boiler. The flow error signal and the integrater are connected to a unit for determining whether the drum level has risen above or fallen below its set limits to push the flow error signal toward a correct value when there is no actual flow error between the feed water to the boiler and flow out of the boiler.</p> |
