| abstract |
An apparatus for performing tests and measurements on liquid samples comprises three identical juxtaposed stationary trays each provided with a plurality of receptacles for the samples to be examined. The receptacles are integrally molded in the trays. The receptacles of the first tray serve as storage vessels for the samples, and the receptacles of the two other trays serve as processing vessels. Three stations arranged above the trays and displaceable with respect to the same in a horizontal plane serve for transferring the samples from the first tray to the second and the third tray, for adding reagents and for discharging the reaction products from the receptacles of the second and the third tray. Each of the stations comprises a carriage displaceable over the trays in an X-direction and a hollow needle for injecting and removing liquids supported by the carriage and displaceable with respect to the same in an Y-direction perpendicular to the X-direction. The carriages and the needles are driven by associated belts, each adapted to be displaced by an associated drum driven by a D.C. motor. The arrangement of the belts and the dimensions of the drums are such that the movement of a needle in one of the said directions does not involve a movement in the other direction, and that each carriage and each needle may be displaced through its entire range by one revolution of the associated drum. |