Analyzer having a rotatable sample rack carrier

An automatic chemical analytical apparatus for analyzing liquid samples comprising:

• (a) a plurality of elongated sample racks, each of which has a length axis and accommodates a plurality of sample tubes, each sample tube being filled with a sample, each sample tube carrying on it an identification readable by a reader device and each sample rack carrying on it an identification readable by a reader device,
• (b) a first sample transport arrangement including a rotatable sample rack carrier located in said sample tube area, said rotatable sample rack carrier accommodating a plurality of said sample racks within a space delimited by a circumference of the carrier, said sample racks being arranged along said circumference with the length axis of each of said sample racks orthogonal to said circumference, said first sample transport arrangement further including a motor for rotating in a step-wise manner said rotatable sample rack carrier, said step-wise rotation comprising rotation intervals and rotation stop intervals, during which said sample rack carrier is at rest,
• (c) second sample transport arrangement for transporting said sample racks from a rack input device of a rack supply unit to said rotatable sample rack carrier, and for selectively transporting said sample racks from said rotatable sample rack carrier to a rack output device of said rack supply unit, said rack input device and said rack output device each accommodating a plurality of said sample racks,
• (d) an automatic pipetting unit for aspirating a portion of a sample contained in any sample tube located in any sample rack carried by said sample rack carrier, said aspirating being effected during a rotation stop interval, and for delivering said aspirated sample portion to any reaction tube in a reaction tube area, said automatic pipetting unit comprising a pipetting needle and means for moving said needle in each one of 3 directions (X, Y, Z) which are orthogonal to each other,
• (e) a controller for controlling and coordinating the operation of said first sample transport arrangement, said second sample transport arrangement, and said automatic pipetting unit, so that a selected sample is delivered to a selected reaction tube;
• and
• (f) computer control means which control the operation of said automatic pipetting unit, said first sample transport means, and said second sample transport means, for minimizing the time interval during which each rack occupies a place on said rotatable sample rack carrier.