• When fluid is allowed to pass through narrow venturi throat then velocity of fluid increases and pressure decreases

• Difference in upstream and downstream pressure head can be measured by using Manometer

U v =    C v√ 2g . ∆H

Why Venturi meter if Orifice meter is available?

• Main disadvantage of orifice meter is power loss due to sudden contraction with consequent eddies on other side of orifice plate

• We can minimize power loss by gradual contraction of pipe

• Ventury meter consist of two tapperd (conical section) inserted in pipeline

• Friction losses and eddies can be minimized by this arrangement

Advantage

·         Power loss is less

·         Head loss is negligible

Disadvantage

·         Expensive

·         Not flexible it is permanent

·         Need technical export

·         Differences between orifice and venture meter