Method and device for liquid transfer with an analysis apparatus
AssigneeRoche Diagnostics GmbH
InventorsKarl-Heinz Mann, Stephan Sattler
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Abstract
The invention concerns a liquid transfer device for an analysis apparatus with a liquid transfer cannula (5) and a capacitive liquid level detector to detect the immersion of the liquid transfer cannula (5) in an analysis liquid contained in a vessel. To reliably check if the liquid transfer cannula (5) is submerged in the analysis liquid or immersed for example in foam it is proposed additionally that resistance is measured by a measurement section (16) in the liquid transfer cannula (5).
Claims27
A liquid transfer device for use with an analysis apparatus, the transfer device comprising:
- a liquid transfer cannula including an interior into which an analysis liquid is suctioned, said liquid transfer cannula including a tip having a lower end, a first control electrode and a second control electrode spaced from one another and defining a measurement section therebetween, said measurement section located primarily within said interior;
- and
- a capacitive liquid level detector comprising a detection circuit adapted to detect a change in capacitance at said tip;
- the capacitive liquid level detector adapted to detect the immersion of the liquid transfer cannula into the analysis liquid;
- said detection circuit further comprising a control device adapted to detect a change in the resistance of the measurement section when the analysis liquid enters the measurement section.
A process for controlling a liquid transfer device of an analysis apparatus, the process comprising:
- providing a liquid transfer cannula including an interior which an analysis liquid is suctioned into, said liquid transfer cannula including a tip having a lower end, and a first control electrode and a second control electrode spaced from one another and defining a measurement section therebetween, said measurement section located primarily within said interior and a capacitive liquid level detector comprising a detection circuit adapted to detect a change in capacitance at said tip;
- lowering said liquid transfer cannula towards an analysis fluid;
- detecting the immersion of the tip of the liquid transfer cannula in the liquid analysis fluid using the capacitive liquid level detector;
- drawing analysis fluid into said interior of said liquid transfer cannula;
- and,
- measuring the resistance of the analysis fluid in the measurement section of the liquid transfer cannula.
Dependencies are inferred from the claim text.