Patent ID: 7000628

Claim:
A liquid metering system comprising: a pump disposed between a liquid supply and a reservoir, the reservoir comprising an inlet connected to the pump, an air/liquid outlet and a liquid outlet, the air/liquid outlet connected to an air separation chamber, the liquid outlet connected to a flow meter and a liquid outlet valve, the air separation chamber connected to an air outlet, the air outlet connected to an air release valve, the air separation chamber accommodating an optical liquid level sensor for sensing the presence of air in front thereof within the air separation chamber, the optical sensor, air release valve and liquid outlet valve being linked to a controller, wherein, when the optical sensor senses air in front thereof, the sensor sends a signal to the controller to open the air release valve and close the liquid outlet valve, and when the optical sensor senses liquid in front thereof, the optical sensor sends a signal to the controller to close the air release valve and open the liquid outlet valve.