8 common reasons for pressure gauge might failure

Why do our pressure gauges break or stop working properly? This is a question we often receive from customers. With decades of pressure measurement experience, we have learned that gauge failures can generally be attributed to the following eight modes.

What is a pressure gauge?

A pressure gauge is an indispensable part of an application's early warning system. By continuously measuring pressure, these instruments help users understand how a process is performing. Pressure gauges are robust and built to withstand demanding environmental conditions. However, even the sturdiest instruments can fail if they are not designed for the specific application or conditions.

Gauge failures can be attributed to one or more of the following eight modes: mechanical vibration, pulsation, extreme temperature, pressure spikes, overpressure, corrosion, clogging, and mishandling/abuse.

Before understanding the causes of problems and how to solve them, it's essential to first understand the internal workings of a mechanical pressure gauge, the most popular type being the Bourdon tube pressure gauge.

The Bourdon tube is a hollow, C-shaped spring element inside the gauge case. When media enters the Bourdon tube, it begins to move—much like a balloon trying to equalize pressure. This movement is translated into a pressure measurement via a linkage (connected to the Bourdon tube through the end piece) and is indicated by a pointer on the dial. The following section will primarily discuss these eight aspects of problems in Bourdon tube pressure gauges.

1. Mechanical Vibration

Extensive research shows that machine vibration in manufacturing plants is a leading cause of pressure gauge failure. Vibration negatively affects gauge accuracy in two ways. Firstly, when the gauge vibrates, it becomes difficult to read the pointer on the dial. Secondly, vibration gradually damages the internal components of the gauge, eventually causing the pointer to shift from zero, leading to fundamental damage to the pressure gauge.

Solution
In most cases, using a liquid-filled case is the most convenient and economical way to protect a pressure gauge from vibration. Alternatively, you can use shock-resistant pressure gauges or install flexible hoses and brackets.

2. Overpressure of the compressor air

This occurs when the system pressure rises instantaneously, reaching the peak rating of the pressure gauge. This can cause permanent deformation or rupture of the gauge's measuring component, the elastic element (Bourdon tube), leading to inaccurate readings or a stuck pointer.

Solution: Select a pressure gauge with overpressure protection or a damping device. Ensure the gauge's range threshold is 1.25 to 1.5 times greater than the actual maximum pressure.

3. Medium Corrosion

When the gas or liquid contains corrosive components, it can corrode the internal elastic element (Bourdon tube) or the connection point, leading to leaks or pointer sticking.

Countermeasures:

• Ensure air media is dry and adequately filtered.

• Consider alternative options such as using a stainless steel case or a diaphragm pressure gauge.

4. Extreme Temperature

If the ambient temperature or the temperature of the fluid medium during operation is too high, it can cause metal expansion and changes in lubricant viscosity, leading to reading deviations or sluggish response.

Countermeasures:

• Pay attention to the temperature in the working environment.

• Select models rated for high temperatures.

• If necessary, install a heat shield or use capillary extension for remote mounting.

5. Improper Installation Location

Incorrect installation methods, such as tilting or loose threads, can cause issues ranging from poor sealing or an inconvenient dial orientation for reading, to more serious problems like gas leakage or physical damage to the gauge body due to stress.

Countermeasures:

• Check the gauge installation to ensure it is mounted vertically and securely fastened.

• Use PTFE thread seal tape for sealing threads.

• Adjust the angle for easy reading.

6. Clogging

In pneumatic systems, it is common for oil, water, dust, or particles in the air to be inadequately removed due to inefficient filtration. This can easily clog the pressure port, causing the gauge to respond sluggishly or not at all.

Solution:

• Check the operation of the drain valve in the filter.

• Regularly clean the pressure sensing line.

• Install isolation valves, filters, or flushing valves.

7. Aging

Long-term use and repeated pressure cycling can cause fatigue deformation of the elastic element (Bourdon tube) in the pressure gauge, leading to zero-point drift or reduced sensitivity.

Solution:

• Regularly calibrate the Bourdon tube pressure gauge.

• Perform maintenance and keep records according to the usage cycle.

8. Improper Operation

Although the Bourdon tube pressure gauge has a metal casing, it is not designed to withstand mechanical shock, pulling, or stepping forces. It is built to handle natural conditions like vibration in harsh environments. Sometimes, personnel may unconsciously grab or step on the instrument for balance when moving equipment or climbing. This is incorrect and can lead to sudden breakage, causing falls, and resulting in deformation or damage to sensitive components (such as the Bourdon tube, diaphragm, or strain gauge).