This document discusses manometers and Bourdon tube pressure gauges. It provides advantages and disadvantages of manometers, such as their large size, sensitivity to temperature and gravity changes, and low maintenance. The characteristics of manometric fluids are also outlined. The document then explains the working of Bourdon tube pressure gauges, which use a curved metal tube to indicate pressure. As pressure increases inside the tube, it straightens out and rotates a pointer on a scale to display the pressure reading. Spiral and helix tube designs provide greater sensitivity.

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 7
● Advantages & Disadvantages of Manometer
● Bourdon Tube Pressure Gauge
Lecture Outcomes
O After completion of this lecture, students will be able to –
○ Discuss Advantages & Disadvantages of Manometer
○ Explain the working of Bourdon Tube Pressure Gauge

3. MANOMETERS
 Large in size & can be break
easily
 Readings change with
change in gravity,
temperature and altitude
 Sensitivity changes when
manometric fluid changes
ADVANTAGES DISADVANTAGES
 Construction is simple &
cost is less
 No effect of vibration
 Low to Medium pressure
can be measured by it
 Very low maintenance
 Good accuracy & sensitivity

4. Characteristics
required for
manometric fluid
 It should be non-corrosive, non-
poisonous and stable
 Surface tension, capillary, vapour
pressure should be less
 Coefficient of thermal expansion
should be less

5. Bourdon Tube
Pressure
Gauge

6. Bourdon Tube Pressure
Gauge
Bourdon tube pressure gauges are used for the
measurement of relative pressures from 0.6 to
7,000 bar.
They are classified as mechanical pressure
measuring instruments, and thus operate without
any electrical power.

7. A bourdon tube obeys Hooke's
Law, that is within elastic limits.
Its free end will experience a
movement that is proportional
to the fluid pressure applied.
The measuring element named
for bourdon is partially flattened
metal tube formed in a 250° Arc.
The tube is sealed at one end
(the tip ) and connected to the
pressure at the other end
(socket).

8. Any pressure inside the tube
exceeding the pressure on the
outside causes the tube to
become more circular in cross
section.
As a result, the tip moves in an
arc.
This movement is connected
through a level, quadrant and
pinion to a pointer which moves
round a scale to indicate the
pressure

9. Where greater sensitivity is required, the
bourdon tube may be constructed in the form of
a Spiral or Helix.
Spiral Bourdon Tube Helix Bourdon Tube

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THANKS!
Do you have any questions?
You can find me at
niharprajapati1992@gmailcom
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