PUMP

摘要

This pump has a simple structure that can suppress contact between a balance disk and a balance sheet. The multistage pump 200 is provided with a rotating shaft 1; impellers 2 mounted on the rotating shaft 1; a balance mechanism 70 for balancing the axial thrust acting on the rotating shaft 1; a pump casing 3 which accommodates the impellers 2 and the balance mechanism 70; balance piping 75 which allows communication between a balance space 73, which accommodates the balance mechanism 70 in the pump casing 3, and a fluid intake-side space in the pump casing 3; and a check valve 100 which is disposed in the balance piping 75 and which allows a fluid to circulate only in the direction from the balance space 73 towards the fluid intake-side space.