basic idea of bourdon pressure gauge ,its working,contruction and types

2. •The Bourdon tube is the namesake of Eugéne
Bourdon, a French watchmaker and engineer who
invented the Bourdon gauge in 1849.
•Over the years, the Bourdon tube has entrenched
itself as the elastic element in most pressure
gauges in application today.

3. Pressure gauge
Pressure gauge, instrument for measuring
the condition of a fluid (liquid or gas) that is
specified by the force that the fluid would
exert, when at rest, on a unit area.
Gauge pressure
Pressure above the atmospheric pressure.
P(gauge) = P(absolute) – P(atmospheric)

4. Bourdon tube pressure gauges are the most
common type in many areas and are used to
measure medium to high pressures.They cover
measuring spans from 600 mbar to 4,000 bar.
The measuring element is a curved tube with a
circular, spiral or coiled shape, commonly called
a bourdon tube.

5. Basic Principle of Bourdon tube pressure
gauge
 when an elastic transducer ( bourdon
tube) is subjected to a pressure, it
deflects. This deflection is proportional to
the applied pressure when calibrated.
 when pressurized, a flattened tube tends
to straighten or regain its circular form in
cross-section.

6. CONSTRUCTION
• The pressure input is given to a
socket which is soldered to the tube at
the base.
• The other end or free end of the
device is sealed by a tip.
•This tip is connected to a segmental
lever through an adjustable length link.
The lever length may also be
adjustable.
• The segmental lever is suitably
pivoted and the spindle holds the
pointer.
•A hair spring is used to fasten the
spindle of the frame of the instrument
to provide necessary tension for
proper meshing of the gear teeth and
thereby freeing the system from the
backlash.

7. CONSTRUCTION
•Any error due to friction in the spindle
bearings is known as lost motion. The
mechanical construction has to be
highly accurate in the case of a
Bourdon Tube Gauge.
•We consider a cross-section of the
outer edge will have a larger surface
than the inner portion. The tube walls
will have a thickness between 0.01
and 0.05 inches.

8. • The applied pressure acts on the
inner walls of the bourdon tube.
• Due to the applied pressure, the
bourdon tube tends to change in
cross – section from elliptical to
circular.This tends to straighten the
bourdon tube causing a
displacement of the free end of the
bourdon tube.
• As the free end of the bourdon tube
is connected to a link – section –
pinion arrangement, the
displacement is amplified and
converted to a rotary motion of the
pinion.
• As the pinion rotates, it makes the
pointer to assume a new position on
a pressure calibrated scale to
indicate the applied pressure
directly.

9. Helical Bourdon Gauge
• Helical is a bourdon tube
wound in the form of helix.
• It allows the tip movement
to be converted to a circular
motion. By installing a
central shaft inside the helix
along its axis and connecting
it to the tip, the tip
movement become a
circular motion of the shaft.

10. Spiral Bourdon Tube
• Spiral BourdonTube is made
by winding a partially
flattened metal tube into a
spiral having several turns.
• It produces a greater tip
movement with a C-bend
bourdon tube.
• It is mainly used in low-
pressure application. Spiral
bourdon tube is shown in
figure.

11. Standard Bourdon tube
pressure gauge
suitable for liquid or gaseous
media, which are not highly
viscous or crystallising.
copper alloy
The measuring range covers
0.6 to 1,000 bar.
Bourdon tube pressure
gauges with increased
corrosion resistance
increased corrosion
resistance.
stainless steel.
They are suitable for the
measurement of pressures
from -1 to 7,000 bar.

12. ADVANTAGES
These Bourdon tube pressure gauges give
accurate results.
Bourdon tube cost low.
Bourdon tube are simple in construction.
They can be modified to give electrical
outputs.
They are safe even for high pressure
measurement.
Accuracy is high especially at high pressures.

13. They respond slowly to changs in pressure
they are subjected to hysterisis.
They are sensitive to shocks and vibrations.
Ampilification is a must as the displacement of the
free end of the bourdon tube is low.
It cannot be used for precision measurement.

14. APPLICATION AND USES
 Gauge made of stainless steel can be applied to
applications that require high purity levels, due to
their higher resistance.
 It is used in foot pump to in indicate pressure
developed.
 The bourdon tube is used in analog pressure meter.
Common applications
• Machine and plant engineering
• Gas distribution
• Aerospace
• Automotive
• Medical
• General Industries

15. MAINTENANCE
 Recalibration - Recalibrating a pressure gauge will increase the efficiency of
the component by ‘zeroing’ the pointer.
 Venting procedures - In some cases, pressure gauges offer an inaccurate
reading due to inadequate ventilation causing a build-up of pressure.
 Correct storage -When the pressure gauge is not in use, it is important to
store the component at room temperatures.This will ensure mechanical efficiency
when the gauge is to be used again.
 Oil filled pressure gauge should be frequently maintained as they are subject to
higher temperatures .

16. Non-full-scale loadable andfull-scale loadable Bourdon
tube pressure gauges
Non-full-scale loadable
Black triangle
Full scale loadable
No black triangle
Non-Full scale loadable

17. The main difference between the
instruments is that “non-full-scale
loadable Bourdon tube pressure
gauges” should not be operated
permanently in the range above 75 %
of the full-scale value (FS). Otherwise,
under continuous pressure loading,
irreversible deformations can occur
with the measuring system

18. Sources
http://www.instrumentationtoday.com
http://instrumentationandcontrollers.blogspot.com
https://www.mgacontrols.com
https://www.polytechnichub.com
https://blog.wika.com
http://www.idc-online.com

19. ThankYou