| 摘要 |
Apparatus for metering one or more liquids includes at least one tank (2) for the liquid to be metered, a pipe (6, 6b)) for drawing off the liquid, having an end nozzle (8) for delivery of the liquid to a storage container. A recirculation pipe (10) communicates with the draw-off pipe (6, 6b) and with the tank (2) for recirculating to the tank the liquid to be metered A reversible pump (18) is associated with the draw-off pipe and operates in suction or compression mode, and includes a non-return valve (16a, 16b) associated with the recirculation pipe (10) to close the recirculation pipe when the pump (18) is operated to draw off a metered quantity of the liquid and open the recirculation pipe, closing the draw-off pipe when the pump is operated in compression mode. A shut-off valve (24) communicates with the pump (18), with the delivery nozzle (8) and with the draw-off pipe for closing in the direction of the delivery nozzle and for opening in the direction of the pump, to allow, when the pump is operated in suction mode, drawing off of a metered quantity of the liquid and, when the pump is operated in compression mode, selective recirculation of the liquid, and assuming a second position for opening in the direction of the delivery nozzle (8) and closing of the draw-off pipe to deliver a metered quantity of the liquid into a storage container, when the pump is operated in compression mode. |
