Method for the visual determination and measurement of the discharge of liquids flowing slowly and with a free level, using air bubbles as measuring medium, and an arrangement for carrying out the method

摘要

The invention relates to a method for the visual determination and measurement of the discharge of liquids flowing slowly and with a free level, using air bubbles as measuring medium, and an arrangement for carrying out the method. By means of the method according to the invention, discharges are intended to be able to be measured directly and without loss with high accuracy, in particular in the case of small flow velocities. The method is characterised in that a) the individual air bubbles (12) are generated with an equivalent bubble diameter in the order of magnitude between 3 mm and 10 mm, preferably of 4.5 mm, and rise with an approximately constant rising velocity from the bottom (8) of the channel up to the fluid surface (13), being driven away during their rise at each location by the amount which corresponds to the local velocity, b) to determine the entire discharge, a picture of the horizontal drift of the air bubbles (12) at the fluid surface (13) is taken using a camera (5) or a plurality of cameras and the picture is subsequently digitally processed and evaluated by means of a microprocessor (6) connected to the camera (5) or the cameras for determining the discharge data and for evaluation. <IMAGE>