Metric PVC Flowmeters

Video: How to Measure Flow Rate Using a Variable Area Flowmeter (3mins) - Summary at bottom of page

Variable area flowmeters, sometimes called VAFs or rotameters, are simple devices that can be put in systems to measure the flow of fluid. They must be mounted vertically – if they are mounted horizontally, they will not work. VAFs simply rely on the water flow flowing around a weighted cone – the faster the velocity of the water, the higher it pushes the cone up the flowmeter. The flow is then measured using the scale on the VAF – you must use the top of the weighted cone as the indication of what measurement you should take from the scale. As the flow is increased, the weight will lift higher, and as the flow decreases, the weight will drop lower.

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