Difference between diaphragm pressure gauge and bourdon pressure gauge

Difference between diaphragm pressure gauge and bourdon pressure gauge

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Diaphragm pressure gauges and Bourdon pressure gauges are both instruments used to measure pressure, but they operate on different principles and have distinct designs. Here are the key differences between them:

1. Operating Principle:

  • Bourdon Pressure Gauge:

    • The Bourdon tube is the primary element in this type of gauge.
    • The Bourdon tube is a curved, hollow metal tube that tends to straighten when pressure is applied to it.
    • As pressure increases, the tube straightens, causing the attached pointer to move on a dial, indicating the pressure.
  • Diaphragm Pressure Gauge:

    • A diaphragm is the primary sensing element in this type of gauge.
    • The diaphragm is a flexible membrane that deforms in response to changes in pressure.
    • The movement of the diaphragm is translated into a mechanical displacement, which is then used to indicate the pressure on a dial.

2. Construction:

  • Bourdon Pressure Gauge:

    • Typically consists of a coiled or helical Bourdon tube made of metal.
    • Common materials include bronze, brass, or stainless steel.
  • Diaphragm Pressure Gauge:

    • Features a flexible diaphragm usually made of materials like elastomers, metal, or composite materials.
    • The diaphragm is often sealed to prevent the pressure medium from coming into contact with the internal components.

3. Application:

  • Bourdon Pressure Gauge:

    • Widely used in various industries for measuring pressure in gases and liquids.
    • Suitable for applications with relatively stable pressure conditions.
  • Diaphragm Pressure Gauge:

    • Commonly used in applications where there are pressure pulsations or vibrations.
    • Suitable for measuring pressure in corrosive or abrasive media because the diaphragm can isolate the measuring element from the process fluid.

4. Sensitivity and Accuracy:

  • Bourdon Pressure Gauge:

    • Generally has a lower sensitivity compared to diaphragm pressure gauges.
    • May have slightly lower accuracy, especially at lower pressure ranges.
  • Diaphragm Pressure Gauge:

    • Often more sensitive to pressure changes.
    • Can provide higher accuracy, especially in lower pressure ranges.

In summary, while both Bourdon and diaphragm pressure gauges serve the purpose of measuring pressure, their construction and operating principles make them suitable for different applications and conditions. Bourdon gauges are more common and widely used, while diaphragm gauges offer advantages in specific situations where sensitivity, isolation, or resistance to pulsations are critical.