PURPOSE: To suspend only the revolution system of a pump by installing the boss part having the diameter smaller than the inside diameter of a water pumping up pipe into a discharge bowl and making the inside diameter of a connection part between the discharge bowls larger than that of the boss part and forming the shaft receiving supporting boards into a shape properly fitted onto the boss part.

CONSTITUTION: The discharge bowls 3 and 4 set between a water pumping pipe 1 and a bell-mouth 2 are formed so as to expand outside a little for the water pumping pipe 1, and the inside diameter of a connecting pipe 11 is made equal to or a little larger than the inside diameter of an upper stage side boss part 5. The upper and lower stage side shaft receiving supporting boards 15 and 16 can be properly fitted so as to be inserted and demounted from the boss parts 5 and 6 of the upper-stage side discharge bowls 3 and 4. Therefore, a pump main-shaft 12, upper and lower vane wheels 13 and 14, upper and lower receiving supporting boards 15 and 16, and a suction cover body 20 are suspended, and the suspension weight can be reduced markedly.