Patent ID: 8152499

Claim:
An eccentric screw pump with an annular outer part ( 10 ; 40 ; 74 ) and with an inner part ( 12 , 42 ; 72 ) arranged therein, wherein an inside of the outer part ( 10 ; 40 ; 74 ) and an outside of the inner part ( 12 ; 42 ; 72 ) taper towards an axial side ( 16 ; 46 ; 70 ) in a complementary manner, and the inner part ( 12 ; 42 ; 72 ) and the outer part ( 10 ; 40 ; 74 ) are movably mounted relative to one another in an axial direction (X, W), wherein either the axial side to which the inside of the outer part ( 10 ; 74 ) and the outside of the inner part ( 12 ; 72 ) taper, is a pressure side of the eccentric screw pump, and the inner part ( 12 ) in its inside comprises a channel ( 28 ) which is open to the pressure side or to a cavity in the inside of the eccentric screw pump and is in connection with a surface ( 26 ) of the inner part ( 12 ), which is distant to the pressure side, by which means a pressure prevailing on the pressure side of the eccentric screw pump or in the inside of the eccentric screw pump between the inner part and the outer part ( 10 , 40 , 74 ), produces a force acting on the inner part ( 12 ; 42 ; 72 ) axially in a direction in which the inner part ( 12 ; 42 ; 72 ) tapers, or the axial side to which the inside of the outer part ( 40 ) and the outside of the inner part ( 42 ) taper, is a suction side ( 46 ) of the eccentric screw pump, and a pressure channel ( 82 ) is provided, which connects the pressure side or a cavity between the inner part ( 42 ) and the outer part ( 40 ) of the eccentric screw pump, to a surface ( 84 ) of the outer part, which is distant to the pressure side, by which means a pressure prevailing on the pressure side of the eccentric screw pump or in the inside of the eccentric screw pump between the inner part and outer part ( 10 , 40 , 74 ), produces a force acting on the outer part ( 10 ; 40 ; 74 ) axially opposite to the direction in which the inner part ( 12 ; 42 ; 72 ) tapers.