Patent ID: 11872552
Assignee: BECKMAN COULTER, INC.
Field: Chemical engineering (Chemistry)
Classification: CPC B | IPC B  G

Claim 12:
13. A method of using a device for transferring a liquid comprising (a) a piston comprising a stepped profile, a drive rod portion, and a free end portion extending from the drive rod portion, the free end portion having a different diameter than the drive rod portion, (b) a barrel comprising a barrel body, and a tip formed in the barrel body, the barrel comprising a larger diameter segment and a smaller diameter segment, wherein the barrel is configured to engage a first pipette tip sized to fit over the larger diameter segment, and wherein the barrel is further configured to engage a second pipette tip sized to fit over the smaller diameter segment of the barrel, and (c) a first seal element between and engaging the barrel and the free end portion, wherein the barrel comprises a stepped bore defined by the barrel body, the stepped bore comprising an axial hole passing through the tip, the stepped bore further comprising a coaxial counterbore and a bore portion having a diameter that is smaller than a diameter of the counterbore and is larger than a diameter of the axial hole, and wherein the first seal element is fixed to the stepped bore within the bore portion, the method comprising:
in a first high volume pipetting mode, aspirating a first liquid by withdrawing the piston from the barrel, and dispensing the first liquid using the first pipette tip; and
in a second low volume pipetting mode, aspirating, a second liquid by withdrawing the piston from the barrel, and dispensing the second liquid using the second pipette tip.