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给水泵一般将除氧器水箱中的水抽送至锅炉。水箱中的水处于饱和状态。因此,对给水泵来说,除氧器水箱必须较给水泵高出一定的高度(倒灌高度),才能满足给水泵汽蚀余量的要求。由这个高度形成的有效汽蚀余量,要大于给水泵的必须汽蚀余量。否则,就不能保证给水泵的安全运行,发生汽蚀、产生振动、响声,甚至不能出水和损坏泵。尤其在机组甩负荷,除氧器压力突降,泵入口水温还没有下降的瞬间,这对泵抗汽蚀性能的要求更高。汽蚀的出现会严重的影响泵的安全运行和寿命。因此,在给水泵的设计中,必须重视首级抗汽蚀性能。下面就这个问题,作比较详细的介绍。
The water pump normally pumps the water in the deaerator tank to the boiler. The water in the tank is saturated. Therefore, the feed pump, the deaerator tank must be higher than the pump to a certain height (backwater height), to meet the feed pump NPS requirements. The effective NPSH formed by this height should be greater than the necessary NPSH. Otherwise, it is impossible to ensure the safe operation of the feed pump, cavitation occurs, vibration, noise, or even out of water and damage to the pump. Especially in the unit load rejection, deaerator pressure drop suddenly, the pump inlet water temperature has not dropped the moment, which is higher pump anti-cavitation performance requirements. The appearance of cavitation can seriously affect the safe operation and life of the pump. Therefore, in the design of the feed pump, we must pay attention to the first level of anti-cavitation performance. Below on this issue, for a more detailed introduction.