| 摘要 |
PURPOSE:To make always stable detection of a liquid level without being affected by ambient environment and without generating inter-device errors by using the pressure in an air hose during the course of nozzle descending as the reference value for detecting and deciding the liquid level. CONSTITUTION:Air is first sucked 10 in a nozzle tip 14 and the pressure in the air hose 12 is maintained at an atm. pressure level. The nozzle tip 14 is moved toward the top of a specimen tube 16 by a prescribed actuator. While the air sucked from the front end of the nozzle tip 14 is discharged 10, the nozzle tip is lowered toward the liquid level of the specimen tube 16. The pressure in the air hose obtd. by sampling after the prescribed time from the start of descending of the nozzle tip 14 by the command from an MPU 28 to an LSU 26 is simultaneously set as a reference value. The change of the pressure in the air hose with respect to the reference value which takes place when the suction port of the nozzle tip 14 is closed by contact with the liquid level is then detected and decision is made that the front end of the nozzle arrives at the liquid level when such change is confirmed. |
