Bourdon Gauge

Bourdon Gauge

Definition

• A Bourdon gauge is a pressure measuring device.

• It is a part of a special class of gauges known as Aneroid Gauges (“Aneroid” means without fluid ). They are often called Mechanical Gauges in modern language.

History

• The Bourdon gauge was invented in 1894 by Eugène Bourdon (1808-1884)

• He was a watchmaker and engineer by profession .

• The gauge created by him could measure pressures up to 100,000 pounds per square inch (690 MPa or 6800 atm), something that had previously been impossible.

Stationary parts:

• A: Receiver block• B: Chassis Plate• C: Secondary Chassis

Plate• D: Posts to join and

space the two chassis plates.

Components

Moving Parts:

1. Stationary end of Bourdon tube.*2. Moving end of Bourdon tube. This end

is sealed.3. Pivot and pivot pin.4. Link joining pivot pin to lever (5) with

pins to allow joint rotation.5. Lever. This an extension of the sector

gear (7).6. Sector gear axle pin.7. Sector gear.8. Indicator needle axle. *9. Hair spring to preload the gear train to

eliminate gear lash and hysteresis.

Working

Within the Bourdon gauge is a thin-walled metal tube, somewhat flattened and bent into the form of a C.

 Attached  to  its  free  end  is  a  lever  system  that magnifies any motion

of the free end of the tube. On the fixed end of the gauge is a fitting you thread into a  boiler  system.  As  pressure  increases  within  the boiler, it travels through the tube and the tube begins to straighten. As the tube straightens, the pointer moves around a dial that indicates the pressure in psi.

How Is It Different From Other Pressure Measuring Devices?

• It works on the same principle as that of the snakelike, paper party  whistle  you  get  at  a  New  Year  party, which straightens when you blow into it.

• The pressure indicated is the difference between that communicated by the system to the tube and the external(ambient) pressure, and this is usually referred to as the gauge pressure. It is then necessary to add on the ambient pressure in order to obtain the (absolute) pressure.

Materials Used for Making A Bourdon Gauge

• Should have elasticity and flexibility

• Corrosive resistance• Lightweight• Cost FactorExamples

Phosphor bronze, Stainless Steel, Beryllium Copper

Merits • Highly accurate • Highly sensitivity • Suitable for very high pressures

Demerits• Very delicate instrument• Malfunctions easily if pressure varies rapidly

Uses

• Bourdon gauges are often fitted to cylinders of compressed gas used in industry and hospitals.

• This gauge is widely used for steam and compressed gases, and frequently forms the indicating element on flow controllers

Manufacturers of Bourdon Gaugesin India

• Alot Hitek Pvt. Ltd• Japsin Instrumention• A L M Engineering &

Instrumentation Pvt. Ltd.• Waree Instruments Ltd.• Wika Instruments India Pvt.

Ltd.• Manometer (India) Pvt Ltd• Precision Industries

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