Vorrichtung zum Messen der Stroemungsgeschwindigkeit einer Fluessigkeit in einer Leitung

1,241,349. Measuring fluid-flow. INSTITUTTET FOR PRODUKTUDVIKLING. July 8, 1969 [July 10, 1968], No. 34348/69. Heading G1R. In a liquid flow-rate measuring device, such as for use in haemadialysis apparatus, liquid flows in direction of arrow 3, into an inlet 2 and a container 1 and via an outlet 4 through a transparent hose 5 to the upper part of a second container 6, provided with an outlet 7 and an air space 11 and the arrangement is such that the liquid flowing through the device contains a certain amount of air which fills the space 11 and due to the static differential pressure between containers 1 and 6 air will flow upwards through a tube 12, provided with a clamp 17, through a restricted outlet 14 into a recess, defined by a bead 16 of rounded cross-section, to form a bubble 18 of steadily increasing size until a portion 18 passes over the bead 16 into the hose 5 and is carried by the fluid-flow past a pair of light measuring sources 8, 9 and 10 arranged at fixed spaced intervals and the time interval between signals from the spaced light sources represents the flow-rate of the liquid in the hose 5.