8 COMMON CAUSES OF PRESSURE GAUGE FAILURE
Pressure gauges indicate if a system or component in a process is operating correctly or not. They are extremely critical and generally require little to no maintenance other than the periodic pressure gauge calibration.
However, it is normal for gauges to wear out over a period of time due to a number of reasons. You must examine them if they fail prematurely or you have to constantly repair them. Failed or broken gauges lead to bad or incorrect decisions, which may further lead to downtime or serious accidents.
Let us look at various causes that lead to pressure gauge failure:
8 Causes of Pressure Gauge Failure
It isn’t uncommon for different pieces of equipment to vibrate, however, excessive vibration leads to gauge failure. Vibrations negatively impact gauge accuracy in two ways:
It makes it difficult to read a pointer accurately when the gauge is vibrating.
It causes an incremental damage to the pointer mechanism since vibration can move a pointer off zero, thus producing inaccurate readings.
Install gauges that resist vibration, such as a liquid-filled or direct-drive gauge with only a single moving part.
Extreme temperatures impact not just the equipment but the gauges as well. They can cause loosening and sweating in metal joints, causing them to crack. If the gauges are not designed to operate in extreme temperatures, they will start malfunctioning in a short period of time.
Use gauges that are designed for extreme temperature conditions to be assured of reliable information for the lifetime of the instrument.
If the process media are corrosive, then the gauges used in these process streams must be made from internal parts that are resistant to corrosion as highly corrosive media damage the sensing material in the gauges.
Install a diaphragm seal constructed from a material that can withstand the corrosive materials used in the process.
If you use any viscous media or medium containing suspended particles or with crystallizing or congealing properties, it can potentially clog the pressure system and give unreliable gauge readings. The clogged gauges often ‘freeze’, which can be really dangerous as it may indicate no pressure when the system in fact might be under tremendous pressure.
It would be ideal to use a diaphragm seal equipped with flushing ports to constantly flush the diaphragm surface.
If the media you use produces steam or high pressure vapors, it can damage the internal components of the gauge.
You can install a mini-siphon with an internal chamber or a full siphon to reduce the surges. Include a coil for horizontal applications and a pigtail for vertical ones.
Pulsation causes regularly occurring over pressure spikes. A rapidly cycling medium within a pressure system can cause the gauge pointer to move erratically, causing the pressure gauge to spike intermittently and leading to the breakdown of the internal parts.
You can address this issue by installing a restrictor or a pressure snubber which help in slowing down the media by reducing the size of the intake orifice and minimizing the pressure fluctuations.
In most cases, the process media is transported through piping systems at relatively high pressure and gauges that are appropriate for that pressure are installed for process monitoring. However, if the workers switch pumps on and off, or open or close valves, then a surge of media flows through the pipe, impacting the pressure gauge and causing a spike that damages the gauge.
You must use reliable gauges whose tolerances are several times higher than the standard flow pressure or install over pressure protectors on gauges where over pressure spikes tend to occur.
If the pressure gauge isn’t handled properly or if they are mistreated, they will start to malfunction earlier than expected. It is important to conduct regular maintenance and safety training for all the employees who work closely with pressure gauges.