Automated chemical testing apparatus

1,240,304. Automatically dispensing samples. J. J. MORAN. 25 Oct., 1968 [14 June, 1968], No. 6502/70. Divided out of 1,240,303. Heading B1X. [Also in Division F1] Apparatus for dispensing controlled amounts of liquid samples from sample containers 46 on turntable 32 into a plurality of reaction tubes 24 which may be carried by an endless belt (see Specification 1,240,303) comprises conduit 62, means comprising piston-cylinder assembly 117, 118 (Fig. 8) for aspirating a controlled amount of the sample from a container 46 into the conduit and for ejecting aliquots of the sample into each of a row of reaction tubes 24, carriage car 64 supporting the conduit and movable along and carried by arm 66, arm 66 being pivotable at one end for movement between the pick-up station (dotted lines in Fig. 1) and the discharge station, and means for controlling the amount of sample aspirated into and ejected from conduit 62. Fig. 8 shows conduit 62 immersed in continuously fed wash-water cup 85, washmotor 108 controlling piston-cylinder assembly 102 for taking wash-fluid into the conduit and expelling it, piston-cylinder assembly 104 connected to car 64 for raising and lowering conduit 62, piston 106 connected to car 64 and cylinder 107 connected to the conduit for aspirating air-bubbles into the conduit and motor 112, reversible clutch 114 and worm gear 116 for moving cylinder 118 relative to piston 117 for aspirating and dispensing sample liquid. At each sample withdrawal operation there is aspirated into conduit 62 a water segment, an air bubble, a sample segment, another air bubble and finally a slight excess of the sample, the excess being expelled to waste before the sample dispensing operation begins. The whole apparatus may be automatically controlled (Fig. 9 not shown).