| 摘要 |
The present invention relates to a flow meter, particularly for liquids, having an impeller wheel arranged in a vertical tubular measurement bore and acted on by a flow stream. The impeller wheel has a bearing shaft, the ends of which are rotatably mounted in axially and radially guiding bearings respectively. The impeller wheel has one or more vanes, the flow-on attack surfaces of which are inclined to the direction of oncoming flow of the stream. A sensor detects the rotary frequency of the impeller wheel. A movable wall subdivides a chamber into two chamber halves, one of which communicates with an inlet connection and the measurement bore upstream of the impeller and the other one of which communicates with an outlet connection and the measurement bore downstream of the impeller. In order, with such a flow meter, to make possible in simple manner and at low cost of manufacture a high precision of measurement over the entire measurement range, the bearing shaft is arranged with axial play between the bearings and the impeller wheel is acted on from below by the flow. In this connection, the attack surfaces are so inclined with respect to the direction of flow that the force component, directed in the approach direction, of the force exerted by the flow stream on the impeller wheel is equal to or greater than the weight of the impeller wheel.
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