Also known as volumetric quantitative dispenser, belong to the pressurised action type, that is, by the lubrication pump delivery of pressure oil agent to push the piston of the metering parts, the last has been stored in the metering parts of the oil in the capacity chamber forced to the lubrication point, when the system unloads the capacity chamber re-storage of oil agent, for the next work to prepare. The system must work intermittently and the matching lubrication pump must have an unloading function. The lubrication pump only discharges oil once during a working cycle. And the distance between the metering pieces far, near, low, lying or standing have no effect on the displacement. Accurate measurement, sensitive action, oil discharge smoothly.