The spring tube pressure gauge, commonly known as a Bourdon tube pressure gauge, operates on the principle that a curved, hollow tube tends to straighten or change shape when subjected to internal pressure. This mechanical deformation is used to measure and display pressure.

Working Principle:

1. Pressure Application:

• The gauge contains a curved, hollow tube (the Bourdon tube), which is typically C-shaped, spiral, or helical in design.

• One end of the tube is sealed, while the other end is connected to the pressurized fluid.

2. Deformation of the Tube:

• When fluid pressure enters the tube, the internal pressure causes the tube to expand slightly and attempt to straighten due to the force acting on its walls.

3. Mechanical Linkage and Movement:

• The sealed end of the tube is connected to a mechanical linkage and gear mechanism.

• As the tube straightens under pressure, this motion is transferred to the gears, amplifying the movement.

4. Display on the Dial:

• The gear mechanism drives a pointer that moves over a calibrated dial, displaying the pressure reading in desired units (e.g., psi, bar).

Key Features:

• The amount of tube deformation is proportional to the pressure applied, allowing accurate measurement.

• Bourdon tube gauges are widely used due to their simplicity, durability, and ability to measure a wide range of pressures.