Differences between venturi meters and orifice meters

Venturi meter

A venturi meter is a flow measurement instrument which use a converging section of pipe to give an increase in the flow velocity and a corresponding pressure drop from which the flow rate can be deduced. They have been in common use for many years, especially in the water supply industry

Contents

• Venturi meter
• Orifice meter
• Differences between Venturimeter and Orificemeter
• References

Orifice meter

An orifice meter or orifice plate is a flat plate having a central hole that is placed across the flow of a liquid, usually between flanges in a pipeline. The pressure difference generated by the flow velocity through the hole enables the flow quantity to be measured.

Differences between Venturimeter and Orificemeter

1. A venturi meter can be used to measure the flow rates of all incompressible flows (gases with low pressure variations, as wells as liquids), whereas an orifice meter is generally used for measuring the flow rate of liquid.
2. Venturi meters are only installed in pipelines, and the accelerated flow through the apparatus is subsequently decelerated to the original velocity at the outlet of the venturi meter. The flow continues through the pipe line. In the orifice meter, the entire potential energy of the fluid is converted into kinetic energy, and the jet discharges freely into the open atmosphere.
3. In a venturi meter,the flow velocity is measured by noting the pressure differences between the inlet and the throat of the venturi meter ,whereas in the orifice meter the discharge velocity is measured by using a pitot tube or a trajectory method.