Viscous material pump, in particular for the conveyance of concrete

Claim 1

A viscous material pump comprising: a housing (3) receiving the viscous material to be pumped, said housing having a wall containing a conduit opening by which the viscous material is passed from the pump and an opposing wall containing a pair of cylinder openings; a swivel body (26) having a material passage extending between a discharge opening (32) and an inlet opening (28), the area (A 2 ) of said discharge opening (32) being of a different size than the area (A 1 ) of said inlet opening, said swivel body being movably positioned in said housing intermediate said opposing walls for alternately connecting the cylinder openings with the conduit opening; and a swivel shaft (44) from which said swivel body extends, said swivel shaft being mounted on said housing for moving said swivel body about an axis of rotation (35) extending generally in the direction of the swivel body passage, said discharge and inlet openings of said swivel body being radially displaced from the axis of rotation such that the product of the area (A 2 ) of the discharge opening (32) and the displacement (R 2 ) of the center of gravity of that area from the axis of rotation is similar to the product of the area (A 1 ) of the inlet opening (28) and the displacement (R 1 ) of the center of gravity of that area from the axis of rotation.