Patent ID: 7581935

Claim:
A thick matter pump with two conveyor cylinders ( 50 , 50 ′) communicating via two end openings ( 52 ) in a material supply container ( 54 ), the conveyor cylinders ( 50 , 50 ′) operated in counter stroke by a hydraulic reversible pump ( 6 ) via hydraulic drive cylinders ( 5 , 5 ′) driven by the reversible pump, the hydraulic drive cylinders ( 5 , 5 ′) each having a rod end and a base end; with a hydraulically actuated pipe switch ( 56 ) provided within the material supply container ( 54 ), the pipe switch having an inlet and an outlet, which pipe switch inlet is alternatingly connectable to one of the openings ( 52 ) of the conveyor cylinders ( 50 , 50 ′) freeing the respective other opening of the conveyor cylinders ( 50 , 50 ′), and which pipe switch outlet is connected with a conveyor conduit ( 58 ), wherein the drive cylinders ( 5 , 5 ′) are hydraulically connected at the base end via respectively one hydraulic conduit ( 11 , 11 ′) to a connector of the reversible pump ( 6 ) and at their rod end are hydraulically connected with each other via an oscillating oil conduit ( 12 ); with at least two cylinder switch sensors ( 20 , 20 ′; 22 , 22 ′) in predetermined separation from each other and spaced from the rod ends and/or base ends of the drive cylinders ( 5 , 5 ′) and sensitive to the passage by of a piston ( 8 , 8 ′) of the drive cylinder; and with a device ( 18 ) for controlling the thick matter pump responsive to the output signal of each cylinder switch sensor for reversing the reversible pump ( 5 ) and the pipe switch ( 56 ) after completion of a piston stroke, wherein the device is a computer assisted reversing device including a measurement and evaluation routine for determining, by measurement or computation, the temporal displacement of the piston on its way between the two cylinder ends, as well as for computing therefrom a derived initiation time for the subsequent reversing of the reversible pump and the pipe switch.