Measurement Of Pressure Reference From Fluid Mechanics book ( mahajan publication)

1. ARHAM VEERAYATAN INSTITUTE
OF ENGINEERING, TECHNOLOGY & RESEARCH
PRESENTED BY
KOTADIYA URVISH(150920106001)
KATHIRIYA VISHAL(15092010603)
VYAS KEYUR (150920106004)
MEASUREMENT OF
PRESSURE
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2. TOPIC
1. Units of Pressure Measurements
2. Pascal’s Law
3. Atmospheric ,Absolute ,Gage Pressure and Vaccum Pressure
4. Measurement of Atmospheric Pressure
5. Manometers
6. Micro manometer
7. Mechanical gage
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 Pressure is define as force divided by area. (exerts on solid, gas,
liquid)
 The unit of pressure is in Pa, psi, atm, bar, torr
F = force in newton/ lb
A = area in m2/ in2
P = F/A
1 psi = 6895 pa
1 bar = 105 Pa
1 atm = 101325 Pa
1 torr = 133.3 Pa
1. Units of Pressure Measurements

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System Length Force Mass Time Pressure
MKS Meter Newton Kg Sec N/M2 =
Pascal
CGS CM Dyne Gram Sec D/CM2
English Inch Pound Slug Sec PSI
Continue…….

5. 2. Pascal’s Law
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amF



6. Continue…..
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2
)(:
2
:
z
appz
y
appy
zsz
ysy






 sinz;cos ssy 
sz
sy
pp
pp


 szy ppp 
 sinsxPzxpF syy 
zzzz a
zyx
sxpyxpF
2
cos

 
ya
zyx
2


za
zyx
2


Y:
Z:

7. 3.Atmospheric,Absolute,Gage,Vaccum Pressure
1. Atmospheric pressure :- the local atmospheric air exerts a normal pressure upon all
surfaces which is known as Atmospheric pressure.
2. Absolute pressure :- when pressure is measured above absolute zero as datum it is called
Absolute pressure.
3. Gage pressure :- when it is above the Atmospheric pressure as a datum it is called Gage
pressure.
4. Vaccum Pressure :- when it is below Atmospheric pressure as datum it is called Vaccum
Pressure.
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8. Continue…..
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9. 4.Measurement of Atmospheric Pressure
 There are three types of Atmospheric Pressure
1. Mercury Barometer
2. Aneroid Barometer
3. Barograph
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10. Aneroid

11. 5. Manometers
1. Simple manometer
1. piezometer
2. U-Tube manometer
3. Single column manometer
2. Differential manometers
1. Inverted U-Tube manometer
2. U-Tube Differential manometer 30 April 2017
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12. Continue…. Piezometer
 This is the most elementary manometer which can be used for measuring
moderate pressure of liquids.
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Continue….U-tube Manometer
Principles: Hydrostatic Law
∆P=ρ g h

14. Continue…. Single column manometer
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15. - It is used for measuring the difference of low pressure, where accuracy is the
prime consideration
Continue…. Inverted Differential Manometer

16. Continue…..U- tube Differential manometer
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17. 6. Micro manometer
 Definition :- A micro manometer is a special type of manometer designed
to measure extremely small difference in pressure.
 There are two type of micro manometer
1. prandtal manometer
2. Air type centrifugal micro manometer
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I. Bourdon Gage:

Principles: change in curvature of the tube is proportional to difference of
pressure inside from that outside the tube
Applications: tire pressure, pressure at the top or along the walls of tanks or
vessels
7. Mechanical gage

19. Diaphragm (Ancient, mechanical)
If each element is sealed
with a known, fixed internal
pressure, flex will depend
on pressure change on
outside. Stacking amplifies
effect!

20. Bourdon Pressure Gage
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21. Thank
you
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