Abstract: A volume sensing device for determining the volume of liquid present in a standard plastic disposable pipette during a pipetting operation, which operation can be an aspiration or dispensing of liquid. The device comprises a cylinder made of hard synthetic material into which a disposable pipette is lowered at a predetermined velocity. The pipette which is being lowered into the cylinder holds an amount of liquid the volume of which the volume sensing device approximately determines. A pair of metal rings are coaxially mounted near the top end of the plastic cylinder. The pair of metal rings are preferably mounted in mating machined recesses of the plastic cylinder. This pair of metal rings is separated from each other by a small gap which forms the dielectric material of a capacitative circuit when the upper ring is connected to one portion of this circuit and the lower ring is connected to an other portion of the capacitative circuit.

Abstract: An improved automated pipetting system for programmingly pipetting predetermined quantities of liquid between preselected groups of test tubes, vials or wells arranged on a horizontal table. A substantially rigid overhead frame mounted over the table on which the test tube arrays or the like are arranged. A pair of parallel X-axis guide shafts mounted in the rigid frame. A pair of helical screws rotatably mounted in the frame parallel to the pair of X-axis guide shafts. Each helical screw is driven by a stepper motor coaxially connected thereto. A pair of X-axis roller sections are movably mounted on the pair of X-axis guide shafts and support a Z-axis probe mechanism via a pair of Y-axis guide shafts and a parallel Y-axis helical screw. A stepper motor is drivingly and coaxially connected to the Y-axis screw for moving the Z-axis probe mechanism along the Y-axis guide shafts. The Z-axis probe mechanism is movably mounted on the pair of Y-axis guide shafts.

Abstract: An automated pipetting system for performing programmed pipetting procedures on an array of fluid containing test tubes, vials or wells. The system includes a frame which is placed above a horizontal table which holds the array. The frame is equipped with a pair of X-axis guide shafts and a pair of X-axis helical screw shafts. A subframe which is mounted on the X-axis guide shafts is equipped with a pair of Y-axis guide shafts and a Y-axis helical screw shaft. A carriage is mounted on the Y-axis guide shafts and at least one row of probes is mounted on the carriage. A Z-axis drive independently drives the probes in a Z-axis direction relative to the array.