Control system for a two-cylinder thick matter pump

A control system for a pump, the pump having two hydraulic drive cylinders, two pistons supported and driven within each respective drive cylinder, and two feed cylinders, each feed cylinder being adapted to receive a respective piston therein, the pistons being adapted to feed matter from a material vessel through the feed cylinders and a pipe switch and, in turn, into a feed line, the pipe switch being pivotable so as to be open to the feed line during the pressure stroke and be open to the vessel during the suction stroke, comprising:

• first means for delivering hydraulic fluid to the drive cylinders to drive the pistons therein;
• second means coupled to the first means for actuating the pipe switch;
• a reversing valve coupled to the first means and second means and adapted to be actuated upon a respective piston reaching the end of its stroke to, in turn, reverse the direction of hydraulic fluid flowing to or from each respective drive cylinder and the pipe switch;
• a pressure equalizing line extending from one end of one of the drive cylinders towards the other end of the cylinder, and including a check valve therein for correcting the stroke of the piston driven within the respective drive cylinder;
• two pressure switching valves, each pressure switching valve being coupled to one end of the other drive cylinder and to the reversing valve for actuation thereof in response to a change in pressure in the respective end of the drive cylinder;
• and
• third means supported near the ends of the feed cylinders adjacent to the drive cylinders and electrically coupled to the reversing valve for actuating the reversing valve in parallel with the pressure switching valves, the third means being responsive to the triggering elements coupled to each respective piston to actuate the reversing valve upon one of the pistons reaching the end of its stroke in the direction toward the respective drive cylinder.