Various Pressure Measuring Equipments Piezometer and Manometer

1. Unit 1 Introduction,
Pressure & Pressure
Measurement
Hydraulics (Sem 3)
Diploma Civil Engineering
GP Palanpur
Lecturer:
Mr. Nihar V. Prajapati
niharprajapati1992@gmail.com

2. Lecture 5
✘ Various Pressure Measuring Equipments
✘ Piezometer and Manometer
Lecture Outcomes
After completion of this lecture, students will be able to -
• Identify Various Pressure Measuring Equipments
• Explain the working and use of Piezometer and simple U-
tube Manometer
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3.  Pressure Measuring
Equipments
A. Manometers
B. Mechanical Gauges

4. A. Manometers
Manometers are the devices used to
measure the liquid pressure from the liquid
column head or the height difference
between two heads.
Fluid used in manometer is called
‘manometric fluid’
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5. Types of Manometers
5
Piezometer
Simple U-tube
Manometer
Differential
Manometer
Inverted Manometer
Inclined tube
Manometer
Micro-manometer

6. 1. Bourdon tube pressure gauge
2. Diaphragm pressure gauge
3. Bellows pressure gauge
4. Dead weight pressure gauge
These gauges show the difference between absolute pressure and
atmospheric pressure.
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B. Mechanical Gauges

7. 1. Piezometer
Piezometer is a simple manometric
device which measures pressure at
a point in a fluid, without balancing
any other fluid column
A ‘L’ shaped pipe is attached to a
container or a pipe flowing liquid.
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8. 1. Piezometer
Here one end of the L shaped pipe
is placed at the point where
pressure is to be measured and
another point is kept open to the
atmosphere.
Due to pressure head, liquid rises in
a piezometer
By measuring the height h, we can
calculate pressure (absolute
pressure)
P = w.s.h = γ.h = ρ.g.h
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9. 1. Piezometer
Limitations
✘ Only used for measuring low to
medium pressure since the
height of liquid is directly
proportional to the pressure
✘ We cannot measure Negative
pressure
✘ Pressure of gases cannot be
measured
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10. Example
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1. Water rises to 120 cm when
a piezometer is attached to
the pipe. Calculate the
pressure in the pipe.

11. 2. Simple U-tube manometer
This type of manometer is U shaped, with
one end open to the atmosphere. It has a
liquid whose specific gravity is greater than
that of the fluid whose pressure is to be
measured.
Mostly Mercury (Sg 13.6) is used as
manometric fluid.
Due to this high pressure can be measured
by a manometer.
It can measure both positive and negative
pressures. It utilizes the principle of specific
gravities.
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12. Positive Pressure
For equilibrium,
Total Pressure in left side = Total Pressure in right side
Pressure at A + Pressure Head in = Pressure Head in Right column +
Left column Pressure at B (= 0)
PA + w.s1.h1 = w.s2.h2 -
Pressure at A in terms of water column, PA = w.h
h = s2.h2 - s1.h1 … m of water
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13. Negative Pressure
For equilibrium,
Total Pressure in left side = Total Pressure in right side
Pressure at A + (Pressure Head = Pressure at B (= 0)
of liquid column in Left column) +
(Pressure Head of mercury column
in Left column)
PA + w.s1.h1 + w.s2.h2 = 0
Pressure at A in terms of water column, PA = w.h
h = -(s2.h2 + s1.h1)… m of water
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14. 14
Thanks!
Any questions?
You can find me at:
niharprajapati1992@gmail.com