Automatic analyzer

Abstract

Pressure fluctuations are sampled at fixed time intervals and subjected to arithmetic processing, using as a trigger the event (or a sign temporally close to that event) of the reverse motor rotation for the backlash correction, thereby discriminating normal suction from suction of sample liquid with undesirable air bubbles.

1 . An automatic analyzer comprising:
 a nozzle for suctioning a sample liquid;   a pressure source for generating pressure to suction the sample liquid into the nozzle and discharge the sample liquid therefrom;   a pipe for connecting the nozzle and the pressure source; and   pressure measurement means for measuring the pressure inside the pipe;   wherein the automatic analyzer includes:   storage means for storing a pressure fluctuation for each amount of sample liquid suctioned;   calculation means for performing a comparing process or an arithmetic process to the pressure fluctuation stored in the storage means; and   detection means for detecting whether or not an air bubble is present inside the pipe by using the calculation means for comparing a pressure fluctuation detected by the pressure measurement means during a predetermined period of time with a stored pressure fluctuation stored in the stored means, the detection mean using as a trigger for the detection a syringe operation during the normal suctioning operation of the nozzle to compare the pressure fluctuation detected by the pressure measurement means with the stored pressure fluctuation in the storage means.   
   
   
       2 . The automatic analyzer according to  claim 1 , wherein
 a syringe is used as said pressure source, and the event of reverse motor rotation for correcting the jolting motion of a gear of a drive source of the syringe is used as said trigger.