摘要 |
An aspirator/dispenser of liquid has a sensor for sensing contact with the liquid by the dispense vessel, which uses constant pressure air expelled out the tip of the dispense vessel. The sensor is improved in that the line of air pressure feeding into the vessel is vented in parallel with the vessel, to the atmosphere, so that the spike of pressure occurring when the vessel encounters the liquid, is released out the vent, rather than the vessel, thus avoiding bubble formation in the liquid. |