Fluid mechanics

Venturi Meter

Many flow meters work by changing the flow area at a measuring section and reading the resulting pressure difference. The venturi meter is one of them.

A venturi meter measures discharge in a pipeline. Its head loss is lower than that of an orifice meter, which is why it is preferred at higher flow rates. It consists of a converging tube followed by a diverging tube, joined at the throat (the section with the smallest cross-section).

The meter is installed along a pipeline with enough straight length to stabilise the flow. Pressure taps are placed at four points along the meter. The pressure-head difference between sections can be read on a manometer. A valve at the end of the pipeline sets the discharge.

Specifications

Dimensions150 × 40 × 150 cm
Power supply220 V
Pipe materialGalvanised steel, PPR, PLA
Maximum pressure1.5 bar
Pipe diameter26 mm
Throat diameter16 mm

Learning outcomes

  • Measure the water flow rate using the manometer height.
  • Observe head losses across the venturi.