| 摘要 |
The invention relates to a method and a device for flow measurements of small liquid volumes through a thin tube. The measurement of small liquid volumes on the order of e.g. 1-500 mu l/h is important, especially for medication dispensers. Gas bubbles are fed into the tube, the diameter of the gas bubbles being essentially the same size as the inside diameter of the tube. The liquid flow pushes the gas bubble forward. The flow time of the gas bubble is determined at pre-set measuring points which are located at a predetermined distance from each other along the tube. A control signal may be emitted according to the flow time and may be used to control the flow rate. The method and the device are suitable for electrically conductive liquids, in which variations in the electrical resistance is determined in the direction of the flow when the bubbles enter the measuring section.
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