AME Unit 9 Q7 – Answer

(a) Measuring Temperature with a Bourdon Tube:

Imagine a classic Bourdon tube, typically used for pressure measurement, but with a twist. In this case, the tube is filled with a temperature-sensitive liquid instead of gas. Let’s delve into its operation with the help of a sketch:

Sketch:

  1. Bourdon Tube: The curved metal tube remains central to the device.
  2. Temperature-Sensitive Liquid: The interior of the tube is filled with a liquid whose volume expands or contracts significantly with temperature changes.
  3. Temperature Change: As the surrounding temperature rises or falls, the liquid inside the tube expands or contracts accordingly.
  4. Tube Deformation: This expansion or contraction alters the curvature of the Bourdon tube due to the liquid volume pushing against the tube walls.
  5. Linkage Mechanism: A linkage mechanism connects the free end of the tube to a pointer or dial indicator.
  6. Temperature Reading: As the tube bends, the linkage translates the movement to the indicator, displaying the corresponding temperature on a calibrated scale.

Key Points:

  • The choice of liquid inside the tube is crucial, typically featuring high thermal expansion coefficients for greater sensitivity.
  • This type of thermometer is well-suited for harsh environments due to its robust construction and lack of fragile components.

(b) Typical Application and Location:

One typical application for a Bourdon tube temperature gauge is in industrial settings, mounted directly on:

  • Pipelines: Monitoring the temperature of fluids flowing through pipes in various processes, like cooling water systems or oil pipelines.
  • Tanks and Vessels: Measuring the temperature of liquids stored in tanks or vessels, such as chemical reactors or boilers.
  • Machinery: Monitoring the operating temperature of critical components in engines, compressors, or other machinery.

Remember, while Bourdon tube temperature gauges offer reliability and versatility, their accuracy limitations compared to electronic counterparts might need consideration depending on the specific application.