Pressurised quantitative dispenser, also known as volumetric quantitative dispenser, belongs to the pressurised action type, i.e. the pressure oil agent delivered by the lubrication pump pushes the piston of the metering piece, the oil agent which has been stored in the metering piece chamber will be forced to the lubrication point, when the system is unloaded the chamber will re-store the oil agent for the next work.