History of Venturi meter, Introduction, Construction, Working Principle, Types of Venturi meter, Limitations & Precautions , Characteristics of Venturi-meter, Applications of Venturi-meter , Advantages & Disadvantages. Overview: Clemens Herschel (March 23, 1842 – March 1, 1930) was an American hydraulic engineer. He is best known for developing the Venturi-meter, which was the first large-scale, accurate device for measuring water flow. A Venturi-meter is a device used for measuring the rate of flow of a fluid flowing through a pipe. It is used to calculate the velocity of fluids running through a pipeline. The fluid may be a liquid or a gas. By reducing the cross-section area of flow passage, a pressure difference is created and the measurement of pressure difference enables the determination of discharge through pipe.

1. And Beneficent
Who Is Most Merciful

2. VENTURI-METER
Group Members:
Esharib Zaheer (BChE-FA16-019)
Safdar Saleem (BChE-FA16-027)
Arslan Khan (BChE-FA16-035)
Awais Qasim (BChE-FA16-041)

3. CONTENTS: 3
 History
 Introduction
 Construction
 Working Principle
 Types of Venturi-meter

4. ….CONT 4
 Limitations & Precautions
 Characteristics of Venturi-meter
 Applications of Venturi-meter
 Advantages & Disadvantages

5. HISTORY: 5
 Clemens Herschel (March 23, 1842 –
March 1, 1930) was an American hydraulic
engineer.
 He is best known for developing
the Venturi-meter, which was the first
large-scale, accurate device for measuring
water flow.
 He played a major part in the construction
of the hydroelectric power plant at Niagara
Falls, which was the first large-scale
electric power plant.

6. INTRODUCTION TO VENTURI-METER: 6
 A Venturi-meter is a device used for measuring the rate of flow of a fluid
flowing through a pipe.
 It is used to calculate the velocity of fluids running through a pipeline.
 The fluid may be a liquid or a gas.

7. ….CONT 7
 They consist of a short length of pipe shaped like a vena-contracta, or
the portion with the least cross-sectional area, which fits into a normal
pipe-line.
 It uses a converging section of pipe to give an increase in the flow
velocity and a corresponding pressure drop from which the flowrate
can be deduced.
 Hence, Venturi-meters are flow measurement instruments which use
a converging section of pipe to give an increase in the flow velocity.

8. CONSTRUCTION OF VENTURI-METER: 8
It consists of three parts;
 Converging Part
 Cylindrical Throat
 Diverging Part
Construction

9. ….CONT 9
A short converging part:
It is that portion of the Venturi-meter where the fluid gets
converges.
 The function of converging cone is to accelerate the fluid and create
pressure difference between the inlet to the converging cone and
the throat.
Angle of converging cone is from 14° to 20°.

10. ….CONT 10
Short cylindrical Throat:
It is the portion that lies in between the converging and diverging part of
the Venturi.
 The cross section of throat is less than the cross section of the converging
and diverging parts.
 As the fluid enters in the throat, its velocity increases and pressure
decreases.
 The function of throat is to stabilize the flow.

11. ….CONT 11
Diverging part:
It is the portion of the Venturi-meter where the
fluid gets diverges.
The function of diverging cone is to reduce the velocity and increase
the pressure to its original value to the extent it is possible practically.
Angle of diverging cone is from 5° to 7°

12. WORKING PRINCIPLE: 12
 It works under the principle of Bernoulli’s equation and Equation of
Continuity.
 Bernoulli's Statement: it states that in a steady, ideal flow of an
incompressible fluid, the total energy at any point of the fluid is
constant.
 The total energy consists of pressure energy, kinetic energy and
potential energy.
 Mathematically;

13. EQUATION OF CONTINUITY: 13

14. BY MEASURING THE CHANGE IN PRESSURE, 14
THE FLOW RATE CAN BE DETERMINED.
 By reducing the cross-section area of flow passage, a pressure
difference is created and the measurement of pressure difference
enables the determination of discharge through pipe.

15. ….CONT 15
 Venturi-meter flow rate is formulated as:
 Where Cd is the coefficient of venturimeter and its value is less than
1.
 Discharge co-efficient depends upon the Reynolds number and the
size of the Venturi, increasing with diameter.

16. FLOW EFFECT IN A VENTURI METER 16
 The velocity profile through a Venturi-meter;

17. TYPES OF VENTURI-METER 17
There are
three
types of
Venturi-
meter;
Horizontal
Venturi-
meter
Inclined
Venturi-
meter
Vertical
Venturi-
meter

18. HORIZONTAL VENTURI-METER 18
 Kinetic Energy Maximum
 Potential Energy Minimum (Negligible)

19. INCLINED VENTURI-METER 19

20. VERTICAL VENTURI-METER 20
 Potential Energy Maximum
 Kinetic Energy Minimum (Negligible)

21. LIMITATIONS: 21
 They are very large in size
and hence where the space is
limited they cannot be used.
 Expensive initial cost,
installation and maintenance.
 They can not be altered for
the flow measurement to a
wide range.

22. PRECAUTIONS: 22
 Drive out all the entrapped air
from differential Mercury
manometer.
 Maintain a constant flow-
rate(Discharge) before taking
any reading.

23. CHARACTERISTICS OF VENTURI METER: 23
 Theoretically there is no restriction to the flow down the pipe.
 They can be manufactured to fit to any required pipe size.
 The temperature and pressure within the pipe does not affect the
meter or its accuracy.
 There are no moving parts.
 Unfortunately the accurate shape required of the inside of the meter
makes them relatively expensive to manufacture.

24. INDUSTRIAL APPLICATIONS OF
VENTURI-METER

25. INDUSTRIAL APPLICATIONS: 25
 Venturi-meter allow operators to properly monitor and control process
flow.
 It is used to more easily detect system failures.
 They are used in wastewater pipes because their overall design
structure allows for solids to pass through it instead of collecting in front
of it.
 The Venturi in carburetors is used to measure airflow in a car engine.

26. ….CONT 26
 Calculating flow rate of fluid in a tube.
 Settling the flow of gasoline in the ignition system of a motor vehicle.
 In the field of medicine, Venturi-meter is designed to measure the rate of
blood flow in the arteries.
 It can be used to measure the flow rates of water, gases, suspended
solids, slurries and dirty liquids.

27. Advantages
&
Disadvantages

28. ADVANTAGES: 28
 It has less chances of getting clogged with sediment particles.
 It has High coefficient of discharge.
 It can be installed vertically, horizontally and inclined.
 Loss of energy is minimum.

29. THE RECOVERY OF PRESSURE IS NEAR TO THE INITIAL OR
ORIGINAL PRESSURE OF FLUID ENTERED.

30. DISADVANTAGES:- 30
 Its cost is high.
 Occupies more space than orifice meter.
 Maintenance is not easy.
 Cannot be used in pipes below 7.5 cm diameter

31. REFERENCES: 31
 https://www.engineeringtoolbox.com/flow-meters-d_493.html
 http://www.codecogs.com/library/engineering/fluid_mechanics/pipes/v
enturi-meters.php
 https://learnprotocols.wordpress.com/2012/07/21/venturi-meter-
theory-operations-working/
 http://webcache.googleusercontent.com/search?q=cache:http://www.
mecholic.com/2016/11/venturi-meter-construction-working-equation-
application-advantages.html

32. ANY QUESTIONS?