Flow measurement by orificemeter and venturimeter

Flow measurement is the quantification of bulk fluid movement. It is important to know the amount of material entering and exiting the process to control various industrial processes. Different types of meters are used for flow measurement and it is selected based on the applicability of the instrument on a specific problem, installed cost and costs of operation, the range of flow rates, and its accuracy.

In the following sections we will be discussing about the venturimeter and orifice meter, vastly used in the industries for flow measurement of liquids and gases.

Venturimeter

Venturimeter works on the principle of head flowmeter. Venturi tube gradually reduces the flow area, thus creating differential pressure across it. Any changes in fluid flow rate through venture are measured in terms of diffenential pressure across it.

It consists of convergent inlet cone (having included angle between, 19 degree to 23 degree), a uniform diameter throat (having length equal to its diameter) and a divergent outlet cone (having included angle between 5 degree to 15 degree).

The high pressure tap located on the convergent section while low pressure tap is located at the middle of the throat. The manometer is connected between these taps.