Hyperion, Inc.

Bu S Chen

An improved precision diluter/dispenser device is provided with features for effecting automatic compensation for non-linearity of aspirated fluid volumes of the particular piston and cylinder syringe assemblies that are included with the diluter/dispenser device in order to enhance the accuracy of the device by varying the piston stroke length in order to correct for non-linearity of aspirated or dispensed fluid volumes. Suitable correction factors are programmed into the control mechanism of the device in order to automatically make the necessary adjustments in stroke length so as to significantly enhance the linearity of the movement of fluid volumes throughout the working volume of the piston and cylinder assembly, whether the movement of fluid be of a very small percentage or a very large percentage of the volume capacity of the assembly. Additionally, an improved seal assembly is provided within a precision diluter/dispenser device in order to enhance the accuracy and precision life of the device and to reduce service requirements.

Compensating diluter/dispenser

In the automatic liquid sample diluter disclosed herein, an excess of the sample liquid is drawn into the apparatus through a path which includes a conduit section of precisely predetermined volume. Valving means then switch this conduit section into the diluent discharge path so that accurate dilution ratios are obtained merely by controlling the discharged diluent volume.

Sample diluting apparatus

The diluter disclosed herein consists of a control and drive unit and a diluent module which is connectable to the control and drive unit to form a diluter apparatus. In the diluent module, which can be removed and replaced for the rapid and non-contaminating substitution of diluents, a diluent piston engages the walls of a cylindrical diluent reservoir which has an outlet at one end. A bore through the diluent piston receives and supports a second, smaller piston which can be moved independently of the diluent piston. With appropriate connections to the drive unit, the small piston may be moved in a direction away from the diluent outlet, thereby aspirating a small sample of liquid placed in contact with a spout which communicates with the diluent outlet. Subsequent movement of the diluent piston toward the outlet enables the dispensing from the spout of the relatively small sample of liquid along with a relatively large quantity of diluent. The drive unit includes separate, preferably coaxial, drive rods having engagement portions for releasable connection to the pistons of the diluent module. A stepping motor drives the diluent piston and a motor control unit includes selector means permitting the selection of the precise number of incremental rotations of the stepping motor's rotor, thereby enabling selection of the precise quantity of diluent to be dispensed when the diluent piston is driven toward the outlet.

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Miami, FL, United States of America

Bu S Chen