There are two main water filling methods before the start-up of single-stage centrifugal pump: one is to fill water by assembling the bottom valve, which is a one-way valve installed at the inlet of the inlet pipe. The disadvantage of this method is that the head loss of the bottom valve is large, which affects the device efficiency of single-stage centrifugal pump; The other is water filling without bottom valve. The advantage of this method is energy saving. Compared with the pump station with bottom valve, it can save energy by 10% ~ 15%.Manual water filling method: for small pump stations with inlet pipe diameter less than 300mm, a bottom valve is usually set at the inlet of the inlet pipe. Generally, manual water filling method is adopted, that is, water is filled by a water filling funnel (or an inverted ordinary bottle with bottle bottom removed) from the special water filling exhaust hole on the upper part of the pump shell. For small pump stations with inlet pipe diameter less than 300mm, a bottom valve is usually set at the inlet of the inlet pipe, and the pump can also be filled with water from the outlet pipe orifice of the pump (pump station with short outlet pipeline). Because there is no need to buy other water filling equipment, this water filling method is more common in small rural pumping stationsSelf diversion and water filling method: for the pump house with semi submerged type (i.e. the pump station with the elevation of the inlet pipe and the pump top below the water surface of the inlet pool), the water can be introduced into the pump by itself without manual irrigation and water diversion. The disadvantage of this pump station is that it does not make full use of the water absorption capacity of the pump, and the installation elevation of the pump is reduced, which not only increases the excavation of the foundation, but also inconvenient operation and management; But the advantages are also obvious, that is, it is easy to realize the automation of the pump station and has strong timelinessVacuum water tank filling method: for small pump stations without bottom valve, vacuum water tank filling method can be adopted. The vacuum water tank is a closed water tank welded with iron sheet, and its volume is three times that of the inlet pipe. The installation position of the water tank should be as close to the water pump as possible, and the bottom height of the water tank should also be slightly lower than the axis of the water pump. The height of the vacuum water tank is generally twice the diameter of the water tank.