Double-suction centrifugal pump

A double-suction centrifugal pump comprising:

• a rotational shaft;
• an impeller secured to the rotational shaft;
• a casing that accommodates the impeller therein;
• and
• legs secured to the casing,
• wherein the casing includes a suction volute that communicates with a suction port,
• the casing includes an upper casing and a lower casing fastened to each other,
• at least one rib is provided on each of both side surfaces of the lower casing constituting the suction volute,
• the at least one rib extends in a radial direction of the rotational shaft when viewed from an axial direction of the rotational shaft, and
• the at least one rib is separated from the legs,
• wherein the at least one rib provided on each of both side surfaces of the suction volute comprises a plurality of ribs, and
• wherein the plurality of ribs are located in a fan-shaped area whose central line coincides with a vertical line passing through a central axis of the rotational shaft when viewed from the axial direction of the rotational shaft, and a central angle of the fan-shaped area is 140 degrees or less.