Carousel and tip

Claim 1

In a pipette system having a generally cylindrical pipette nozzle having an attachment end defining a passageway, having an end surface and having an outer generally cylindrical surface which can engage a pipette tip, means for achieving axial movement of said pipette nozzle and a pipette tip having a generally cylindrical inner surface detachably affixed to said pipette nozzle by engagement of said inner surface of the pipette tip with the outer surface of the nozzle in fluid communication with said passageway; the improvement comprising employing as said pipette nozzle a pipette nozzle having an outer surface defining a plurality of generally cylindrical pipette nozzle sections each having a nozzle section height and a nozzle section diameter, said nozzle section diameter for each of said pipette nozzle sections being different from that of the others with the generally cylindrical pipette nozzle section of smallest nozzle section diameter being adjacent to the end surface of said nozzle and the other generally cylindrical pipette nozzle sections positioned in order of increasing nozzle section diameter away from the end surface and employing as said tip a disposable pipette tip comprising an elongated truncated conical double open-ended tube section having a small end defining a passageway for vacuum uptake and pressure discharge of liquid and a large end joined to and in fluid communication with a first end of a pipettereceiving collar portion extending radially away from the conical tube section, said collar portion having a bell mouthed opening at its second end and an inner surface defining a plurality of generally cylindrical tip sections each having a tip section height and a tip section diameter different from that of the others with the generally cylindrical tip section having of largest diameter being adjacent to the bell mouthed opening and the other generally cylindrical tip sections positioned in order of decreasing tip section diameter toward the first end of the collar the tip section height and tip section diameter of each of the tip sections being related to the nozzle section height and nozzle section diameter of a nozzle section so as to permit nestling insertion of said nozzle into the collar of said tip, at least two of said plurality of generally cylindrical tip sections each carrying an inward-extending circumferential sealing rib, the at least two ribs being axially displaced from one another, being integral with the collar portion and capable of deforming in contact with a generally cylindrical collar section to give a vacuum uptake and pressure discharge seal upon direct nontwisting axial insertion of the nozzle of said pipette into the collar portion via its bell mouthed open end.