Anticoagulant metering device and method

Abstract From the Canadian patent

of Disclosure, An aspiration wand assembly having an associated metering valve for metering liquid anticoagulant to blood aspirated by the wand. The metering valve includes a flexible diaphragm normally obstructing conduit which transmits anticoagulant from a remote source to the tip of the aspiration wand. An orifice communicates the diaphragm with the interior of the aspiration wand so that various negative pressures in the wand correspondingly draw the diaphragm into any one of a plurality of positions away from the obstructing position.