Patent ID: 8366388
Filing Date: 2013-02-05
Classification: F04D

Abstract:
1. A multi-stage centrifugal pump comprising a pump housing ( 3 ); a pump shaft ( 12 ) rotatably mounted in the pump housing, a motor-side end of the pump comprising at least one cylindrical shaft section ( 21 ) and a splined shaft section ( 22 ) connecting thereto; at least two impellers ( 8 ) arranged in a rotationally fixed manner on the splined shaft section the impellers being clamped between an abutment ring ( 33 ) seated on the pump shaft ( 12 ) and a free end of the pump shaft; and an axial face seal ( 13 ) incorporated between the cylindrical shaft section ( 21 ) and the pump housing ( 3 ), wherein the axial face seal ( 13 ) comprises a stationary axial face seal ring ( 14 ) arranged in the pump housing ( 3 ) sealed with respect to the pump housing, and a rotating axial face seal ring ( 19 ) arranged on the pump shaft ( 12 ) and sealed with respect to the pump shaft ( 12 ), said stationary axial face sealing ring and said rotating axial sealing ring ( 14 , 19 ) comprising respective axial sealing surfaces ( 17 , 18 ) which slide on one another and are impinged to one another by way of a spring force exerted by compression spring means ( 23 ) arranged between two spring holders ( 24 , 25 ), and wherein the abutment ring ( 33 ) is arranged in a transition region ( 34 ) of the pump shaft ( 12 ) between the cylindrical shaft section ( 21 ) and the splined shaft section ( 22 ) as well as between the two spring holders ( 24 , 25 ), wherein positive-fit means ( 26 , 30 ) are provided between the spring holders ( 24 , 25 ), which are effective at least in a working rotation direction ( 32 ) of the pump shaft ( 12 ).