Measuring Vibrations: Impact on Manometers and Measurement Accuracy

vibra
Photo by EJ Yao on Unsplash

The measurement of vibrations is crucial in many industrial sectors, particularly when it comes to the precision of pressure measuring instruments such as manometers. Manometers are used in numerous applications, including hydraulics, pneumatics, the chemical industry, and the energy sector. But how do vibrations affect the measurement accuracy of these devices? And what are the differences between analog manometers, analog manometers with liquid damping, and digital manometers?

Why is Vibration Measurement Important for Manometers?

Manometers are pressure measuring instruments available in various types. They must provide precise measurements, as incorrect pressure values can lead to operational failures or even hazards in industrial plants. Vibrations pose one of the biggest challenges to the accuracy of these devices because they:

  • Mechanically affect the measuring mechanism, causing deviations.
  • Can lead to reading errors in analog displays.
  • Reduce the lifespan of devices due to material fatigue.
  • Can interfere with electronic circuits in digital manometers.

Types of Manometers and Their Sensitivity to Vibrations

There are three main types of manometers, which differ in their design and reaction to vibrations:

  1. Analog Manometers

These classic manometers operate on a mechanical pressure measurement principle, usually via a Bourdon tube. They are particularly susceptible to vibrations, as the measuring mechanism is mechanically influenced. Strong vibrations can cause constant fluctuations in the needle position, making accurate reading difficult.

  1. Analog Manometers with Liquid Damping

These manometers contain a viscous liquid (e.g., glycerin or silicone oil) that stabilizes the needle mechanism and thus reduces the impact of vibrations. The liquid absorbs a large portion of the oscillations, causing the manometer to move more slowly and enabling more precise readings.

  1. Digital Manometers

Digital manometers use electronic sensors for pressure measurement. They are less susceptible to mechanical vibrations but can be affected by electrical interference. Additionally, they often offer an averaging function to smooth out strong measurement fluctuations.

Comparison of Vibration Sensitivity of Manometers

Criterion

Analog Manometers

Analog Manometers with Liquid Damping

Digital Manometers

Sensitivity to Vibrations

Very high

Medium

Low

Measurement Stability

Low

High

Very high

Accuracy under Vibrations

Fluctuating

Relatively stable

Very stable

Long-term Stability

Can be affected by vibrations

Improved by liquid damping

Very high

Reading Accuracy

Difficult under strong vibrations

Good

Perfect

Vibrations can cause significant measurement deviations. The following table shows the average deviations for the three types of manometers at different frequencies:

Vibration Frequency (Hz)

Analog Manometers (%)

Analog Manometers with Liquid Damping (%)

Digital Manometers (%)

10 Hz

±3.5%

±1.2%

±0.5%

50 Hz

±7.8%

±3.0%

±1.1%

100 Hz

±12.5%

±5.2%

±2.0%

500 Hz

±25.0%

±12.0%

±4.5%

1000 Hz

±40.0%

±20.5%

±7.0%

Measures to Improve Measurement Accuracy in Vibrations

To optimize measurement accuracy despite vibrations, various measures can be taken:

  1. Liquid-damped Manometers

A proven method to reduce vibration effects on analog manometers is the use of liquid fillings. These devices contain a damping liquid such as glycerin or silicone oil, which stabilizes the needle mechanism and absorbs uncontrolled oscillations.

Advantages of Liquid Damping:

  • Reduction of needle fluctuations: The liquid dampens mechanical vibrations and enables smoother needle movement.
  • Improved readability: Less severe fluctuations lead to more precise pressure measurements.
  • Longer lifespan: Vibrations cause increased wear in dry manometers, whereas damping reduces this strain.

Disadvantages of Liquid Damping:

  • Temperature dependence: The viscosity of the liquid changes with temperature, affecting the damping properties.
  • Limitation of response speed: Since the liquid slows down the needle, rapid pressure fluctuations may cause delays.
  1. Elastic Mounting Systems

Mechanical vibration stress can be reduced through special mounting systems. These methods help minimize the direct transmission of vibrations to the manometer.

Effective Methods for Vibration Reduction:

  • Vibration dampers: Rubber buffers or spring suspensions absorb vibrations and prevent them from being transmitted to the measuring device.
  • Flexible mounts: These mounting systems allow some movement of the manometer without vibrations directly affecting the measurement accuracy.
  • Shock-resistant housings: Special housings with additional damping elements protect the manometer from sudden shocks and increase resistance to vibrations.

Conclusion

The measurement of vibrations and their effects on manometers is a crucial aspect in many industries. While analog manometers suffer significantly from vibrations, liquid-damped and digital versions offer improved stability and accuracy. By implementing suitable measures, measurement quality can be significantly improved, ensuring reliable pressure monitoring even in highly vibrating environments.

Diese Website benutzt Cookies. Wenn du die Website weiter nutzt, gehen wir von deinem Einverständnis aus.