The Bourdon pressure gauge, like other types, measures pressure. Invented in 1850, the Bourdon-tube gauge remains one of the most widely used instruments for measuring the pressure of various liquids and gases, such as steam, water, and air.
It measures pressure up to 100,000 pounds per square inch (70,000 newtons per square cm). The device consists of a flattened and coiled circular tube.
In this reading, we will delve into the definition of a Bourdon pressure gauge, its various applications, its components, its diagram, its construction, and its operational principles. We’ll also explore its advantages and disadvantages.
Let’s begin!
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What is a Bourdon Pressure Gauge?
Bourdon tubes form radially and have an oval cross-section. The measuring medium’s pressure acts on the inside of the tube, causing movement in the tube’s non-clamped end. This motion indicates the pressure.
C-shaped Bourdon tubes, with an angle of approximately 250°, are suitable for pressures up to 60 bar. For higher pressures, we utilize Bourdon tubes with numerous superimposed windings of the same angular diameter (helical tubes), or spiral tubes with a spiral coil in one plane (spiral tubes).
Bourdon tube-made pressure gauges measure relative pressures from 0.8 to 100,000 psi. They are mechanical pressure measurement tools that do not require any electricity to work. The following are the applications of a Bourdon pressure gauge:
- They measure pressures from medium to very high.
- The product is designed for high-pressure applications, such as steam boilers and compressors.
- It is used for measuring pressure in vehicles’ tube tires.
Construction
An elastic transducer, which is a Bourdon tube that is fixed and open at one end to accept the pressure to be measured, is the major component of this instrument. The Bourdon tube’s other end is open and closed.
The Bourdon tube has an oval cross-section. We have bent the Bourdon tube into the shape of a circular arc. The free end of the Bourdon tube connects to a sector and pinion through an adjustable link. The pinion’s shaft holds a pointer that sweeps across a pressure-calibrated scale.
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Diagram of a Bourdon Pressure Gauge
How Does a Bourdon Pressure Gauge Work?
A Bourdon pressure gauge operates in a less complex and easily understandable manner. The fixed open end of the Bourdon tube connects to the pressure for measurement. The exerted pressure acts on the Bourdon tube’s inner walls.
The cross-section of the Bourdon tube tends to transform from elliptical to circular as a result of the applied pressure. The applied pressure tends to straighten the Bourdon tube, resulting in the displacement of its free end.
The applied pressure is proportional to the displacement of the free-closed end of the Bourdon tube. Attaching the free end of the Bourdon tube to a link-section-pinion configuration amplifies the displacement and translates it into a rotating motion of the pinion.
The pointer moves to a new position on a pressure-calibrated scale as the pinion spins, directly indicating the applied pressure. The pointer represents gauge pressure because the pressure in the casing containing the Bourdon tube is normally ambient.
Advantages and Disadvantages of a Bourdon Pressure Gauge
Advantages:
The Bourdon pressure gauge offers numerous advantages in its various applications.
- The Bourdon tube pressure gauges provide precise readings.
- The Bourdon tube is inexpensive.
- The manufacture of Bourdon tubes is simple.
- By modifying them, we can make them provide electrical outputs.
- Even for high-pressure measurements, they are safe.
- The accuracy is excellent, particularly at high pressures.
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Disadvantages:
- They react slowly to pressure changes.
- They are subject to hysteresis.
- They are susceptible to vibrations and shocks.
- Because the displacement of the free end of the Bourdon tube is so little, amplification is required.
Conclusion
The Bourdon Pressure Gauge is one of the most widely used instruments for measuring pressure in gases and liquids. Known for its reliability, simplicity, and mechanical strength, it converts pressure into mechanical displacement using a curved, flexible tube called the Bourdon tube.
We use a Bourdon pressure gauge to measure pressure. Invented in 1850, the Bourdon-tube gauge remains one of the most widely used instruments for measuring the pressure of various liquids and gases, such as steam, water, and air, up to 100,000 pounds per square inch (70,000 newtons per square cm).
When pressure is applied, the tube straightens, and this movement is transferred via linkages to a pointer on a dial. It’s extensively used in applications such as automotive systems, industrial machinery, hydraulics, and pneumatics, offering a cost-effective and durable solution for pressure monitoring.
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Frequently Asked Questions (FAQs)
What is a Bourdon pressure gauge?
It’s a mechanical device that measures pressure using a curved tube that deforms (straightens) when pressure is applied, moving a pointer on a calibrated dial.
Where is a Bourdon gauge commonly used?
In automotive applications, industrial equipment, hydraulic systems, air compressors, and refrigeration units.
What are the advantages of a Bourdon pressure gauge?
- Simple and robust design
- Accurate and reliable
- No need for external power
- Cost-effective
- Works well in high-pressure applications
What are the limitations of a Bourdon pressure gauge?
- Not suitable for very low pressures
- Affected by vibration and pulsation unless damped
- May require recalibration over time
How accurate is a Bourdon pressure gauge?
Typical accuracy ranges from ±0.5% to ±2% of full-scale reading, depending on the quality and type.
Can a Bourdon gauge be used for vacuum measurement?
Yes, specific compound Bourdon gauges can measure both pressure and vacuum.
What materials are used in Bourdon tubes?
Common materials include brass, stainless steel, phosphor bronze, and Inconel, depending on the application and fluid type.