Bourdon pressure gauge

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

1. BOURDON PRESSURE GAUGE

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 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. what basically is Bordon tube gauge?? 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 T he 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. 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.

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 Bourdon Tube 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. Disadvantage 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 and full-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. Thank You