2. History
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 gaugePressure 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.
Pressure above the atmospheric pressure.
P(gauge) = P(absolute) - P(atmospheric)
4. 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.
5. Working
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.
6. Helical Bourdon tube 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
7. Standard Bourdon tube
pressure gauge
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
8. • These Bourdon tube pressure gauges giveaccurate 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
Advantages
9. Disadvatages
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
10. Application and uses
Gauge made of stainless steel can be applied to applications that require high purity
levels, due totheir higher resistance.
It is used in foot pump to in indicate pressure developed.
The bourdon tube is used in analog pressure meter.
Machine and plant engineering
Gas distribution
Aerospace
Automotive
Medical
General Industries
11. Maintenance
Recalibrating a pressure gauge will increase the efficiency of the
component by "zeroing' the pointer
In some cases, pressure gauges offer an inaccurate reading due to
inadequate ventilation causing a build-up of pressure.
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
12. 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