Abstract: A drainage pump has a pump body, a vane, a ring, and a circumferential wall. The pump has a cylindrical small vane pump chamber and a large vane pump chamber extending from and communicating with the small vane pump chamber. A suction inlet communicates with the small vane pump chamber and a discharge outlet communicates with the large vane pump chamber. A chamber slope portion is formed between the small vane pump chamber and the large vane pump chamber. The vane is adapted to be driven by a motor and is rotatably mounted to the pump body. The vane includes a large vane portion received in the large vane pump chamber and a small vane portion extending from the large vane and received in the small vane pump chamber. The small vane portion and the large vane portion rotate together when driven by the motor. A vane slope portion is formed between the large vane portion and the small vane portion. The ring has a central opening, positioned between the large vane portion and the small vane portion.

Abstract: A pump body 10 of a drainage pump 1A comprises a pump chamber 12, inlet 15, and outlet 17. A rotary vane 300 mounted in the pump body 10 is coupled to a motor mounted above the pump body 10, and comprises a shaft 310 and four large-radial blades 320. Formed below the large-radial blades 320 are small-radial blades 350 to make a liquid at the inlet rise. Lower edges of the large-radial blades 320 are connected together by a disk 350 having an opening at the center and interceptively dividing the surface of the liquid rising from the inlet. Thus the amount of the liquid in contact with the large-radial blades 320 above the disk 350 decreases, and the load to the rotary vane decreases. At the same time, bubbles, noise and vibrations caused by bubbles also decrease. By surrounding the outer circumference of the large-radial blades 320 with a ring member, return water W5 moving back from the outlet 17 when the pump stops is damped by the wall member 360 and returns smoothly to the inlet 15.

Abstract: A pump body 10 of a drainage pump 1A comprises a pump chamber 12, inlet 15, and outlet 17. A rotary vane 300 mounted in the pump body 10 is coupled to a motor mounted above the pump body 10, and comprises a shaft 310 and four large-radial blades 320. Formed below the large-radial blades 320 are small-radial blades 350 to make a liquid at the inlet rise. Lower edges of the large-radial blades 320 are connected together by a disk 350 having an opening at the center and interceptively dividing the surface of the liquid rising from the inlet. Thus the amount of the liquid in contact with the large-radial blades 320 above the disk 350 decreases, and the load to the rotary vane decreases. At the same time, bubbles, noise and vibrations caused by bubbles also decrease. By surrounding the outer circumference of the large-radial blades 320 with a ring member, return water W5 moving back from the outlet 17 when the pump stops is damped by the wall member 360 and returns smoothly to the inlet 15.

Abstract: A pump body 10 of a drainage pump 1A comprises a pump chamber 12, inlet 15, and outlet 17. A rotary vane 300 mounted in the pump body 10 is coupled to a motor mounted above the pump body 10, and comprises a shaft 310 and four large-radial blades 320. Formed below the large-radial blades 320 are small-radial blades 350 to make a liquid at the inlet rise. Lower edges of the large-radial blades 320 are connected together by a disk 350 having an opening at the center and interceptively dividing the surface of the liquid rising from the inlet. Thus the amount of the liquid in contact with the large-radial blades 320 above the disk 350 decreases, and the load to the rotary vane decreases. At the same time, bubbles, noise and vibrations caused by bubbles also decrease. By surrounding the outer circumference of the large-radial blades 320 with a ring member, return water W5 moving back from the outlet 17 when the pump stops is damped by the wall member 360 and returns smoothly to the inlet 15.

Abstract: A drainage pump 1 comprises a pump housing 40 defining a suction inlet 42, a pumping chamber 44 and a delivery outlet 46, and a cover 32. An impeller 50 accommodated in the pump housing is driven by a motor 10. The impeller 50 comprises a shaft 52 coupled to an output shaft of the motor 10, large-radius vanes 60 in form of flat plates radially extending from the shaft 52, and small-radius vanes 54 continuous from the large-radius vanes 60. Outer circumferential edges of the large-radius vanes 60 are connected by a cylindrical wall member 64, and outer circumferential parts of lower edges of the large-radius vanes 60 are connected by an annular member 62. The cylindrical wall member 64 has a rounded portion 70 at its upper end, and the small-radius vanes 54 also have rounded portions 57 at their lower ends.