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

Claim 14:
15. A device for transferring liquid comprising:
a first pipette tip;
a second pipette tip having a different volume than the first pipette tip;
a piston comprising a stepped profile, a drive rod portion, and a fee end portion extending from the drive rod portion, the free end portion having a different diameter than the drive rod portion;
a barrel comprising a barrel body and a tip, wherein the tip is configured to engage the first pipette tip through a friction fit, and wherein the tip is further configured to engage the second pipette tip through a friction fit, wherein the barrel comprises a stepped bore defined by the barrel body, the stepped bore comprising an axial hole and a coaxial counterbore, the axial hole passing through the tip;
a first seal element between and engaging the barrel and the free end portion; and
a second seal element between and engaging the barrel and the drive rod portion;
wherein the piston is disposed within the barrel such that at most one of the first seal element and the second seal element engages between the barrel and the piston;
wherein, in a first high volume pipetting mode using the first pipette tip, the device is configured to aspirate a liquid by withdrawing the piston from the barrel such that the free end portion is above and moves away from the axial hole, and to dispense the liquid by inserting the piston into the barrel such that the free end portion moves toward the axial hole;
wherein, in a second low volume pipetting mode using the second pipette tip, the device is configured to aspirate a liquid by withdrawing the piston from the barrel such that the free end portion remains in the axial hole, and to dispense the liquid by inserting the piston into the barrel such that the free end portion remains in the axial hole.