Abstract: Method and apparatus for supplying a preset quantity of a liquid, using a tank containing the liquid, a check valve distributor, and a hose connecting the tank to the check valve distributor, and having a pumping unit, a solenoid valve, and a pulsed flow meter interposed between the tank and the check valve distributor, including determining a volume difference between a first quantity delivered by the apparatus and a first quantity detected by pulsed flow meter, as the liquid is pumped at constant flow rate, low pressure and under laminar flow, during a first delivery of the liquid; starting a subsequent delivery of the preset quantity of the liquid, by opening the solenoid valve; and stopping the subsequent delivery of the preset quantity of the liquid when a difference between the number of pulses generated by the pulsed flow meter corresponding with the preset quantity, and the number of pulses output by the pulsed flow meter reaches a number of pulses corresponding to the volume difference; and during a