一、问题的提出在水泵安装时,都希望泵轴(卧式泵)距水面越高越好,这样可以减少工程量,节约投资,但这个高度有一定限度,它与水泵吸入口的真空度、液面压力、液体的温度和比重、吸入管路的流速和阻力有关。然而,我们看到三本书用三个不同的计算公式,计算表明相差很大。例如:1台4BA—6型离心泵,流量Q=65～135米~3/时=18～37.5升/秒,扬程H=72.5～98米,转速n=2900转/分,功率N First, the problem raised in the pump installation, all hope that the pump shaft (horizontal pump) from the water the higher the better, this can reduce the amount of work, save investment, but this height has a certain limit, it and the pump suction inlet vacuum The pressure of the liquid surface, the temperature and specific gravity of the liquid, the flow rate and resistance of the suction line. However, we have seen three books with three different calculation formulas, and the calculations show a large difference. For example: a 4BA-6 type centrifugal pump, flow rate Q = 65 ~ 135 meters ~ 3 / hour = 18 ~ 37.5 liters / second, head H = 72.5 ~ 98 meters, speed n = 2900 rpm / minute, power N