The present invention relates to a process pump having a crank drive (1) and having at least three cylinders, which, as viewed clockwise or counterclockwise about the crank drive (1), constitute a first cylinder, a second cylinder and a third cylinder, wherein the crank drive (1) has a vertical crankshaft and, for each cylinder, in each case one crosshead (7, 10, 13) and one connecting rod (8, 11, 14) with in each case one large connecting-rod eye (8a, 11a) for receiving the crankshaft, wherein the crossheads (7, 10, 13) are functionally connected to the crankshaft via the connecting rods (8, 11, 14). The invention is distinguished by the fact that the crankshaft is in the form of an eccentric shaft (5) with a first eccentric and a second eccentric, wherein the connecting rod (8) of the first cylinder and the connecting rod (14) of the third cylinder are arranged on the first eccentric, and wherein the connecting rod (11) of the second cylinder is arranged on the second eccentric, such that the large connecting-rod eye (8a) of the connecting rod (8) of the first cylinder and the large connecting-rod eye of the connecting rod (14) of the third cylinder have a common central axis.