Patent ID: 9221046
Filing Date: 2015-12-29
Classification: B01L

Abstract:
1. An air displacement pipette for aspirating and dispensing a quantity of liquid comprising: a pipette body; a piston mounted for axial movement within the body away from an upper stop position through a home position and to a lower stop position; and a nozzle adapted to receive air into the pipette body and to expel air from the pipette body in response to the axial movement of the piston; wherein the piston comprises a plurality of segments including a first segment and a second segment, the first segment of the piston seals against the pipette during at least a part of a first stroke portion, and the second segment of the piston seals against the pipette during at least a part of a second stroke portion; and wherein a second quantity of air displaced by an axial movement of the piston during the second stroke portion is greater than a first quantity of air displaced by an equivalent axial movement of the piston during the first stroke portion.