Patent ID: 6148666
Filing Date: 2000-11-21
Classification: G01F,G01N

Abstract:
A liquid transfer device for an analysis unit, the liquid transfer device comprising:a liquid transfer needle having a tip; anda capacitive liquid level detector for detecting immersion of the tip of the liquid transfer needle into an analysis liquid by detecting a change in capacitance between a signal electrode and a counter electrode, the analysis liquid being contained in a vessel, said capacitive liquid level detector comprisinga signal electrode, a counter electrode and a detection circuit connected to said signal electrode and said counter electrode for detecting a change in capacitance between the signal electrode and the counter electrode; anda temperature dependent detection resistor disposed adjacent the tip of the liquid transfer needle,wherein said tip of the liquid transfer needle and said temperature dependent detection resistor are movable into and out of the analysis liquid,wherein said detection circuit comprises a current supply for supplying current to the detection resistor, said detection circuit configured to detect a change in resistance of the detection resistor during immersion thereof into the analysis liquid.