Slurry pump with discharge cylinders, especially two-cylinder concrete pump

A slurry pump for mixing concrete slurry, the slurry pump comprising:

• a charge funnel;
• a pair of discharge cylinders operable with the charge funnel so that slurry flows therebetween, each discharge cylinder having an opening through which the slurry flows and a drive for forcing the slurry though the opening;
• a discharge line operable with the charge funnel so that slurry flows therebetween;
• a control valve having an exit port connected with the discharge line and an entrance port that is alternatively positioned in front of the opening of each discharge cylinder;
• a pair of gate valve disks, one on each side of the entrance port of the control valve, wherein the size of each gate valve disk conforms to a surface between the discharge cylinder openings such that in a change-over midpoint of the control valve the openings of the discharge cylinders are sealed off by the gate valve disks, and the entrance port in the control valve is sealed off on the surface between the discharge cylinders for the execution of a partial stroke of a discharge cylinder piston which compresses slurry in the discharge cylinder;
• a compensation cylinder for preventing slurry interruptions during the change-over of the control valve;
• and
• a combinatorial circuit which controls the drive of each discharge cylinder and the slurry flow such that during a change-over of the control valve the compensation cylinder pushes slurry into the discharge line and such that during a subsequent discharge cycle of one of the discharge cylinders the compensation cylinder is filled with slurry, wherein the combinatorial circuit lets the drive of the discharge cylinder actually delivering slurry deliver faster in proportion to the amount of the slurry taken in by the compensation cylinder, and wherein the combinatorial circuit delays the change-over of the control valve such that one of the gate valve disks closes off the opening of the discharge cylinder associated with it.