Bi-directional liquid sample handling system

Claim 1

A machine for automatically transferring at least a portion of a liquid sample in one receptacle to another receptacle, comprising: a head assembly translatable between upper and lower positions along a vertical axis; means for moving said head assembly along said vertical axis; at least one pipette assembly mounted on said head assembly for movement therewith along said vertical axis and for movement in a single first horizontal axis, said pipette assembly including a support block carried on a first horizontal guide member and a pipette nozzle mounted on said support block and having a depending end for receiving tips, a slide block carried on a second horizontal guide member parallel to the first guide member, a plunger mounted on said slide block and depending within said pipette nozzle, and means for moving said plunger within said pipette nozzle to vary the internal volume of said nozzle and a tip supported thereby; means for moving said pipette assembly relative to said head assembly along said first horizontal axis; a table mounted beneath said head for translation along a second horizontal axis that is transverse to the first horizontal axis, said table having at least two work stations spaced along its axis of translation for respectively accommodating at least one tray having a plurality of receptacles; means for moving said table along said second horizontal axis to place any selected one of said plurality of receptacles in a tray mounted on said table at either of said work stations in registry with said pipette assembly; and means for controlling each of said moving means for said head assembly, pipette assembly, plunger and table to effect transfer of a liquid sample between at least one receptacle in said try mounted at one of said stations to at least one receptacle located at the other of said work stations.