Question

What is the difference between a venturimeter and an orifice meter?

Answer 1

Definition

1. A venturimeter is a flow measuring device in which a converging portion of a pipe is used to produce a rise in inflow velocity and a corresponding pressure decrease, from which the fluid's flow rate may be calculated using Bernoulli's equation.
2. An orifice meter is a device with a hole in it that records the pressure drop across the hole to determine how quickly a fluid is moving.

An illustrative diagram of a venturimeter and orifice meter is given below.

Venturimeter:

Orifice meter:

Step 2: Difference between venturimeter and orifice meter

Venturimeter	Orifice meter
The venturimeter consists of three parts, such as a converging section, diverging section, and throat.	The orifice meter consists of a thin plate and a bore.
The pressure loss in the venturi meter is $10\%$.	The pressure loss in the orifice meter is $50-60\%$.
The coefficient of discharge in the venturi meter is $0.98$.	The coefficient of discharge in the orifice meter is $0.6$.
The turn-down ratio of the venturimeter is $10:1$.	The turn-down ratio of the orifice meter is $5:1$.
The venturimeter is more expensive than the orifice meter.	The orifice meter is cheaper than the venturimeter.