Two-end-supported-type three-stage centrifugal pump

The utility model discloses a two-end-supported-type three-stage centrifugal pump which comprises a pump body part, a rotor part, a bearing part and a mechanical seal part. The rotor part comprises a first-stage impeller (11), a second-stage impeller (15) and a pump shaft (25), the first-stage impeller is of a symmetrical double suction type structure, a third-stage impeller (17) with suction inlets facing the same direction is installed in a pump body (18) of the pump body part and at the side edge of the second-stage impeller (15), and the bearing part is divided into a left bearing device (6) and a right bearing device (22) which are installed at the two ends of the pump shaft of the rotor part respectively. Cooling water cavities (38) are formed in a left pump cover (9) of the mechanical seal part and a right pump cover (19) of the mechanical seal part. The two-end-supported-type three-stage centrifugal pump can meet the requirements of a bottom reduction oil pump which can process 3.5 million tons of inferior heavy oil per year, the pump efficiency and the anti-cavitation performance of the two-end-supported-type three-stage centrifugal pump can be greatly superior to those of an original bottom reduction oil pump, and the two-end-supported-type three-stage centrifugal pump will play an important roll in replacing a bottom reduction oil pump of an existing atmospheric and vacuum distillation unit and meeting the requirements of a novel device.