3-piston alternating volumetric pumps for use on misting systems. Can be coupled to various types of motors, directly or with flexible joint. Pump body and cover in die-cast aluminium alloy. Rear cover with oil drain outlet, or incorporate oil sight glass. Pistons driven by crank-connecting rod mechanism. Pump shaft in pressed high-strength steel. Oversized friction bearings. Connecting rods in die-cast special low-friction zinc-aluminium alloy. Bronze connecting rods available. One-piece ceramic pistons. Pump head in pressed brass. Double gasket sealing system. Pump head internal components may be in different materials depending on application. Intake and delivery valves have plugs for easier maintenance. Various regulator valves and accessories can be connected to the pump head.