Patent ID: 7201875

Claim:
A flow cell for use with a flow cytometer comprising: a flow cell body; a sample delivery tube extending into said flow cell body; at least one sheath flow port on said flow cell body, said at least one port allowing introduction of a flow of sheath flow liquid through said flow cell body; a cuvette having flat sides and a rectanaular cross-section, joined to the flow cell body; a channel extending through the cuvette, said channel comprising an initial end and a terminal end, wherein liquid from said sample delivery tube and said at least one sheath flow port flows into said initial end of said channel; and a removable nozzle at said terminal end of said channel through which said liquid from said sample delivery tube and said at least one sheath flow port flows out of said channel, wherein said removable nozzle is positioned on a removable nozzle key having hard planar surfaces on a top and on at least two sides, said nozzle held in a registered position on said flow cell, said registered position at a defined three-dimensional position and at a registered rotational orientation, wherein said nozzle is held in said registered position by contact between said hard planar surfaces of said nozzle key and said cuvette.