JR600SN plunger pump is designed with additional rod between the plunger and crosshead, achieving the mechanical back flow preventer. The operation space at the packing is enlarged, more convenient for changes of the packing. The lube oil channel is designed in the crankshaft, enabling the lube oil to go through the crank throw to lube the big rod end bearing directly. The compact structure enables back-to-back mounting, suitable for twin-pump layout on one unit. JR600SN plunger pump is suitable for acidizing and cementing applications.