Battelle Memorial Institute

Manuel Sanz

Georges Revillet

Rudolf Farkas

Gerard Cuenoud

A constant-volume increment pipetting arrangement for use particularly in connection with analysis of minute specimen volumes of biological fluids. The arrangement, which is designed to have a very low inertia factor, comprises a pumping unit having a pair of two-port valves with a duct running between a port from each valve, wherein at least a portion of the duct wall is movable to provide a variable volume pipetting chamber. The second port of one valve serves as the intake port for the fluid to be pipetted and the remaining port of the other valve serves as the delivery port. Three reciprocating drive elements are provided, connected one each to the valves and to the movable portion of the duct wall. Associated with the drive elements is a sequential control means, wherein the control means portion for the drive element connected to the moving portion of the duct wall constitutes an electromagnet arrangement energizable by a periodic supply. Means are associated with the duct wall drive element for controlling the travel amplitude of the electromagnet's armature and thus the travel amplitude of this drive element. The volume of liquid displaced by the movement of the movable portion of the duct wall which arises from the controlled movement of the drive element associated therewith corresponds to the volume required for the pipetted increment, whatever variations in resistance may be encountered by the duct-related drive element.

Electromagnet motor control for constant volume pumping

An improved device and method for liquid storage and analysis. The device comprises a receptacle defining a U-shaped compartment for a first open-ended branch and a second closed branch. A reaction zone in which the liquid will react with a reagent during analysis is located at the bight interconnecting the branches. The opening in the first branch constitutes a liquid inlet. A wall portion of the second branch spaced from the reaction zone is of self-sealing material which is punctured to release gas from the compartment and to aspirate liquid into the first branch. The material subsequently forms a fluid-tight seal. A wall portion of the body adjacent the reaction zone is made of light-permeable material so that the reaction or the result of the reaction can be optically analyzed. A plurality of such compartments can be provided with a chamber interconnecting the extreme ends of the second branches. A common wall portion of self-sealing material can then be provided for some or all of the compartments.

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Grand-Lancy, Switzerland

Manuel Sanz