Abstract: A passive gravitational drip lubrication system which includes lubrication rate monitoring and control to provide a constant lubrication rate in which the lubricant flow from the reservoir is adjusted by an electromagnetic valve apparatus, a drop detection apparatus senses the amount of lubricant dispensed, and a servo control apparatus adjusts the preselected flow rate by adjusting the electromagnetic valve.

Abstract: Method and apparatus for controlling the flow of a liquid from a supply pipe to a receiving device, to assure that only a preselected liquid is permitted to flow to the receiving device, by: feeding a sample quantity of the liquid from the supply pipe to a sampling receptacle while a main valve between the supply pipe and receiving device is closed; testing the liquid within the sampling receptacle by immersing a stirring device therein, rotating the stirring device by an electrical motor, measuring the load current of the electrical motor, and comparing the measured load current with a reference load current for the preselected liquid; and opening the main valve to permit the flow of the liquid from the supply pipe to the receiving device when the test results show a match of the measured load current with the reference value for the preselected liquid.