Automatic analyzer, dispensing device, and dispensing control method

A dispensing control method for a controlling a dispenser in an automatic analyzer, the dispenser having a nozzle configured to dispense a fluid, a passage having a cross-section, including a position where the cross-section changes, a pressures source configured to generate a fluctuations that controls a flow velocity of the fluid in the dispenser, the method comprising:

• aspirating and dispensing a fluid containing a liquid and the air layer through the nozzle of the dispenser, wherein the air layer includes a gas-liquid phase boundary;
• setting the flow velocity of the fluid during aspiration or discharge to be substantially constant;
• calculating a position of the gas-liquid phase boundary in the passage of the dispenser based on a volume of the air layer aspired in the passage, the cross sectional area of the passage including a portion where the cross section changes, and an integrated value of a flow rate of the liquid that has been aspirated or discharged;
• and
• controlling, during either the aspiration of the liquid into the nozzle or discharge of the liquid from the nozzle, an aspiration amount of the air layer and an aspiration amount or discharge amount of the fluid such that the gas-liquid phase boundary of the air layer does not pass the position in the passage where the cross sectional area of the passage changes to suppress splitting of the air layer.

A dispenser for use in an automatic analyzer for suppressing splitting of an air layer in a passage while allowing a flow velocity of the fluid to be set independently of a critical flow velocity at a position where a cross sectional area of the passage is changed, the automatic analyzer dispenser comprising:

• a nozzle configured to aspirate and dispense a fluid containing a liquid and the air layer, wherein the air layer includes a gas-liquid phase boundary;
• a pressure source configured to generate a pressure fluctuation that controls a flow velocity of aspiration or discharge of the fluid in the nozzle;
• a passage having a cross-section, the passage configured to connect the nozzle to the pressure source, wherein the passage includes a position where the cross section changes, and
• a controller that controls operations of the nozzle and the pressure source,
• wherein the controller is configured to:
• set the flow velocity of the fluid during aspiration or discharge to be substantially constant;
• calculate a position of the gas-liquid phase boundary in the passage based on a volume of the air layer aspired in the passage, the cross sectional area of the passage including where the cross section changes, and an integrated value of a flow rate of the liquid that has been aspirated or discharged fluid;
• and
• control, during either the aspiration of the fluid into the nozzle or discharge of the liquid fluid from the nozzle, the aspiration amount of the air layer and an aspiration amount or discharge amount of the fluid the such the gas-liquid phase boundary of the air layer does not pass the position in the passage where the cross sectional area of the passage is changed changes to suppress splitting of the air layer.