It requires adopters place hands underneath the back and then only lifthead and shoulders.
动作的要领是，将手置于背部下方，只需抬起头和肩即可。
2
For large discharge and low lifthead, it is especially suitable to use tubular pumps for their economic characteristics.
贯流泵是适用于大流量、低扬程的一种经济泵型。
3
With the model, the design of sprinkler pipeline network can be optimized, the optimal lifthead and pipe size were determined, and the annual operational cost was minimized.