The structure of this series of pumps is simple. The dredge pump with diameter below 500wn adopts the horizontal structure of single pump shell and single-stage single suction cantilever. According to the connection mode of gearbox, two typical structures can be provided, that is, the self-contained bracket type is combined with the pump box, the self-contained bracket type lubrication mode is grease lubrication or oil lubrication, and the shaft seal adopts mechanical seal or mechanical seal and packing composite seal. The WN type cabin pump of dredging pump with diameter above 600 adopts the horizontal structure of double pump shell, single-stage and single suction cantilever, with its own bracket, and the lubrication method is forced thin oil lubrication; Wnq underwater dredging pump adopts single pump shell structure to reduce the pump weight and facilitate lifting and movement. All diameter dredge pump shaft seals can adopt spiral sleeve L-shaped rubber seal. The sealing device is composed of three L-shaped sealing rings and a threaded shaft sleeve. In order to improve the service life of shaft seal, sand water separator can be equipped to ensure the quality of shaft seal water.