Apparatus for metering liquids

Apparatus for metering one or more liquids, comprising:

• at least one tank for liquid to be metered;
• a draw-off pipe for drawing off the liquid to be metered from the tank, having an end nozzle for delivery of the liquid to a storage container,
• a recirculation pipe communicating with the draw-off pipe and with the tank for recirculating to the tank the liquid to be metered;
• a reversible pump associated with the draw-off pipe and able to operate in suction mode or compression mode;
• a non-return valve associated with the recirculation pipe and designed to close the recirculation pipe when the pump is operated to draw off a metered quantity of the liquid from the tank and open the recirculation pipe, closing the draw-off pipe when the pump is operated in compression mode;
• and
• a shut-off valve communicating with the pump, with the end nozzle and with the draw-off pipe and able to assume the position for closing the end nozzle and for performing opening in the direction of the pump, so as to allow, when the pump is operated in suction mode, drawing off of a metered quantity of the liquid from the tank and, when the pump is operated in compression mode, selective recirculation of the liquid to a top of the tank, and able to assume a second position for performing opening in the direction of the end nozzle and closing of the draw-off pipe so as to allow delivery of a metered quantity of the liquid into a storage container, when the pump is operated in compression mode.