With This You will able to Learn about Pressure.

1. A. →Definition
B. →Units
C. →Types
D. →Sensing Element
E. →Measuring Instruments
F. →Transducer
G. →Pressure Gauge
H. →Pressure Switch
I. →Differential Pressure Element
J. → Pressure Transmitter
1

2. .
2

3. 3

4. • PSI (Pound per Square Inch )
• BAR
• mm of Hg
• mm of Mercury
• Kg Per Hour
• Torr
• Kpa
4

5. 5

6. a) →Atmosphere Pressure
b) →Absolute Pressure
c) →Gauge Pressure
d) →Deferential Pressure
e) →Vacuum Pressure
6

7. 7

8. 8

9. 9

10. A long glass tube is sealed at
one end and then filled with
Liquid Mercury metal. The
filled tube is then turned
upside down and inserted
into a bowl of mercury, called
a cistern. When this happens,
a small amount of mercury
runs out of the tube into the
cistern, leaving a vacuum at
the top of the tube. Vacuums,
by nature, exert very little or
no pressure on their
surrounding environment.
10

11. Mercury Barometer Aneroid Barometer
11

12. 12

13. 13

14. 14

15. 15

16. 16

17. Pressure above Atmosphere is called
Gauge Pressure.
17

18. Air Pressure in Balloons are the
Example of Gauge Pressure
18

19. 19

20. P = P1 – P2
20

21. 21

22. 22

23. 23

24. 24

25. Hooks Law is the Working
Principle of C-Type Bourdon
Tube .
””the strain in a solid is
proportional to the applied
stress within the elastic limit
of that solid””
“A spring is an object that can
be deformed by a force and
then return to its original
shape after the force is
removed “
25

26. Spiral Type Pressure Gauge
used in Pressure to sense and
Measure Pressure. A
Mechanical Linkage system,
Pointer and Scale attach with
Spiral Tube
:The working principle of
spiral type bourdon tube is
that They Converted Applied
Pressure
to mechanical deflection or
displacement’ The generated
displacement will give the
value of applied pressure.
26

27. Helical Type
Bourdon Tube use
to Sense high
Pressure .
Helical Type
Bourdon Tube
Wound Same Like a
Helix .
27

28. 28

29. 29

30. 30

31. A Manometer is a device use to
measure Differential pressures.
31

32. A manometer works on the principle
of hydrostatic equilibrium.
Hydrostatic equilibrium states that
the pressure at any point in a fluid at
rest is equal, and its value is just the
weight of the overlying fluid.
32

33. This Type of Manometer is
consists of a tube of glass bent
into a U shape.
Then Its Filled with Fluid. The
density of the fluid dictates the
range of pressures that can be
measured. Both ends of the tube
are pressure ports. If one port is
left open to the atmosphere and
the other port is connected to the
pressure to be measured, the
device acts as a gauge pressure
meter. If both ports are
connected to two different
unknown pressures, the
instrument acts as a differential
pressure gauge.
33

34. 34
gh
m
pp 
}/{
}/81.9{
},{
}/{
2
2
2
mNpressuremeasuredp
smgravitytodueonacceleratig
inmdifferencehightManometerh
mkgfluidManometerofdensityp
Where
m





35. p1-p2 = dm.h (1+a2/a1)
Well-Type Manometer, one leg is
replaced by a large diameter well.
Since the cross sectional area of the
well is much larger than the other leg,
when pressure is applied to the well,
the manometer liquid in the well
lowers only slightly compared to the
liquid rise in the other leg. As a result
of this, the pressure difference can be
indicated only by the height of the
liquid column in single leg.
We Can Measure Three Type of
Pressure with this Instrument.
• Pressure
• Vacuum
• Differential Pressure
35

36. 36
columnsinliquidofheighth
gravityofonacceleratig
pressuremeasuredp
pandpbetweendifferencep
hgpp





21
.

37. The Inclined Manometer
use to Measure very
Low of liquid and Gases.
It is Suitable for
Measuring Very Low
Pressure and Where
required greater
accuracy .
P = h * d * sina
37

38. 38
columnsofamgle
fluidofdensityd
axisXatcolumnofheightX
dXp





sin

39. A pressure transducer is a transducer that converts pressure
into an analog electrical signal.
There are Two main types of Transducer.
• Active Transducer
• Passive Transducer
an active transducer has the ability to convert one form of
energy into another form (electrical) without using an
external source of power.
an Passive transducer has the ability to convert one form of
energy into another form (electrical) with using an external
source of power.
39

40. There are Two Main Part of Pressure Transduce.
An Elastic Material Which can Change their Position under
Applied Pressure.
And other is Electrical Device Which can detect and convert
into Electrical Signal.
Main Types of Pressure Transducer :
• Strain Gauge
• LVDT
• Piezoelectric Pressure Transducer
• Capacitive Type Pressure Transducer
40

41. A strain gauge is a sensor which
resistance varies under applied
force;
They change applied Pressure into
an Electrical Resistance which can
be measured.
When external forces are applied
to a stationary object, stress and
strain are the result. Stress is
defined as the object's internal
resisting forces, and strain is
defined as the displacement that
occur.
The Element On of Strain Gauge:
Sensing Element
Strain gauge attach to sensing
element
Convertor and readout device
41

42. LVDT is used to calculate Linear
displacement and works on
Transformer principle.
A Primary and Two Secondary Coil use
in LVDT . A Iron Core attach with Arm
and Move between secondary coil.
Secondary coil connected to series
opposing.
Primary coil attach with AC supply.
Secondary coil attach with OUTPUT.
When Primary Coil Energize .then they
generate magnetic field lines. Then
Magnetic field lines endues voltage in
Secondary coil.
A iron Core use to couple magnetic
lines into Secondary coil.
If Iron Core move to coil1 Then
maximum voltage induces in coil1 and
minimum voltage endues in coil2
42

43. The piezoelectric
transducers work on the
principle of piezoelectric
effect. When mechanical
stress or forces are applied
to some materials along
certain planes, they
produce electric voltage.
This electric voltage can be
measured easily by the
voltage measuring
instruments, which can be
used to measure the stress
or force.
43

44. The Capacitive Transducer Work on
the Principle of variable capacitance .
A capacitive transducer comprises two
Parallel metal Plates. These Plates are
separated by Dielectric Material..
The Distance between two plates is
Variable.
The capacitance of capacitive
transducer changes due to some
reasons like overlapping of plates,
change in distance between the plates
and dielectric.
44

45. Pressure gauge is a Instrument use to measure applied
Pressure.
All pressure gauges have different sensing element, which
can senses the value of measured quantity.
Eugene Bourdon was a French engineer and watchmaker. In
the 1849 he invented the Bourdon pressure gauge, a
measuring instrument of pressure still in use.
45

46. 46

47. The one End of c-type bourdon is
closed and through gear
assembly with pointer on scale.
The second end of bourdon tube
is open and connected to inlet
pressure.
When Pressure applied on
bourdon tube . The Bourdon tube
try expand and gear assembly
also move and pointer indicate
pressure on scale.
The Movement of Pointer on
Scale is directly Proportional to
the of C-Type Bourdon tube
under applied Pressure
47

48. A dead weight tester is a
Instrument use to calibrate
Pressure gauge.
There are three main
Component of this
Instrument.
• A fluid oil that transmit
the Pressure.
• A Weight ad Piston used
to apply the Pressure.
• And a connection port
for Gauge.
48

49. • Check the Zero- error of gauge .
• Select the Weight and place on
Vertical Position,
• Apply Full Range Pressure to
check a full scale deflection.
• Then Reduce Pressure to Check
Pointer Read Zero .
• Turn the Handle for adjusting
piston to ensure that the Weight
and Piton supported by oil
• Spin the Vertical Piston and ensure
that it is floating.
• After System Stabilized Record the
Weight and Gauge Reading.
If you are doing five time calibration ,
Then Increase Weight 0%, 25% 50%
75% and 100% of full Range Pressure
of Pressure Gauge..
49

50. 50

51. The Working Principle of Dead Weight Tester is ‘’Pascal law ‘’
‘’ An external pressure applied to a fluid in a closed vessel is uniformly
transmitted throughout the fluid.‘’
51

52. A Pressure Switch is device That Closes
Electrical Contact when Pressure Reached
to a certain Input Value. This switch Design
to make contact when Pressure Raise or
Fall. Pressure Switch used Widely in
Industries.
Pressure Switch have capsule , Bellows ,
Diaphragm , for sensing of Fluid Pressure
52

53. Pressure Switch use a Sensing
Element that Works against
applied Tension
When Applied Pressure
reached to a set value of
Sensor Then Tension applied
on Spring, Switch contact will
closed.
Pressure switches are used to
monitor the presence of
pressure that is above or
below a set point;
But Pressure switch do not
indicate the amount of
pressure being applied.
53

54. For Measuring
Deferential Pressure
some elements use to
create Differential
• Orifice Plate
• Venturi Tube
• Pitot Tube
54

55. A Pressure Transmitter is a device that
convert Pressure to an Analog Electrical
Signal.
A Pressure Transmitters is used where
high accuracy is Required.
55

56. A pressure transmitter
contains a pressure sensor
plus a signal conditioner to
amplify the output from
the pressure sensor.
Pressure transmitters also
typically contain a display
that shows the pressure
value that is conveyed by
the pressure sensor and
converted into a
standardized output. This
output is typically either 4-
20mA or a digital signal.
56

57. There are four main types of pressure
transmitters:
• Absolute transmitter
• gauge transmitter
• differential pressure transmitter
• multivariable transmitter
57

58. Flow rate is
calculated based
on the
differential
pressure
generated
before and after
an orifice plate.
58

59. 59