Common Reasons for Gauge Failure

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Broken gauges lead to bad decisions, and bad decisions lead to process downtime or accidents. The frustrating part is that most of these expensive and potentially dangerous issues could be relatively easily prevented. An Instrument Audit from WIKA's FAST team can help prevent safety incidents and unscheduled downtime as well as reduce inventory costs due to malfunctioning gauges.

When there are hundreds or even thousands of gauges in a large manufacturing or refining facility, some gauges are going to be damaged or malfunction in a given year no matter the technical proficiency of the maintenance team. It's simply a matter of statistics. Many times, gauge failure can be attributed to misapplication, but all too often, extreme or stressful conditions may cause gauges to fail.

WIKA has identified the common reasons for gauge failure and recommended solutions to help avoid the headaches of frequent replacement and risks of inaccurate readings.
 

1. Temperature


Extremely high or low temperatures can have a negative impact on gauges and other instrumentation. Gauges not designed for these extreme operating conditions can malfunction in a relatively short period of time. Some gauges are designed for extreme temperature conditions and will provide reliable information for the lifetime of the instrument.

Gauges designed for use in extreme temperatures, such as WIKA’s XSEL® process gauge, are made from special corrosion-resistant alloys and can be equipped with cooling fins or a diaphragm seal to isolate the gauge from the hot or cold media.

2. Mechanical Vibration


Numerous studies have shown that vibration is the main cause of pressure gauge failure in manufacturing facilities. Vibration has a negative impact on gauge accuracy in two ways. First, it is difficult to accurately read a pointer on a dial when a gauge is vibrating. Second, incremental damage to the pointer mechanism from vibration can eventually move a pointer off zero, producing inaccurate readings.

Different types of gauges are built to withstand various types and levels of vibrations, and it is critical to use an appropriate, quality gauge for every application. Installing a pressure gauge with low vibration resistance in a high-vibration area is a recipe for trouble. Not only will it have a dramatically shortened lifetime, the vibration might even crack the Bourdon tube and release process media. High quality liquid-filled gauges, which dampen vibrations and minimize stress on internal components, are ideal for high-vibration applications.

3. Overpressure


Process media is normally transported through a piping system at relatively high pressure, and gauges appropriate for that pressure are installed for process monitoring. However, when workers switch pumps on or off, or open or close valves, a surge of media flows through the pipe and impacts the pressure gauge, causing a spike which can damage the gauge. The solution to overpressure problems is to use reliable gauges with tolerances several times higher than the standard flow pressure or to install overpressure protectors on gauges in areas where overpressure spikes tend to occur.

4. Pulsation


Pulsation can be defined as regularly occurring overpressure spikes. When media rapidly cycles through the gauge, the pressure spikes intermittently. The most common solutions for pulsation involve installing a socket restrictor or a pressure snubber, which slows down the media by reducing the size of the intake orifice and minimizes pressure fluctuations.

5. Corrosion


Many process media are corrosive, and any gauges used in these process streams must have internal parts that are resistant to corrosion. Bourdon tubes can corrode and release dangerous process fluid if a gauge made of non-corrosion-resistant material is used or if a gauge made of an appropriate material is used beyond its lifetime. Another solution is to use a diaphragm seal made of a corrosion-resistant alloy, such as WIKA's All-Welded System, which adds an extra layer of protection to ensure the media is kept isolated from the internal parts of the gauge.

6. Clogging

Clogging can be a serious problem for gauges, especially with process media that are subject to congealing or crystallization. Gauges that become clogged often "freeze up," creating a dangerous situation of indicating no pressure when in fact the system is under tremendous pressure. The best solution for most clogging problems is to use a diaphragm seal equipped with flushing ports to constantly flush the diaphragm surface.

7. Misapplication and Mishandling

Misapplication, or putting in the wrong kind of gauge for an application, is a common problem. For example, if a line is pumping oil at 100 PSI, a non-expert may mistakenly install a 100 PSI gauge, not realizing this leaves no allowance for overpressure, surging, or spiking, and will significantly shorten the lifetime of even a quality gauge.

Gauges can be tricky to install properly, and a poor installation can leave the gauge vulnerable to breakdown from any of the causes discussed above. Gauges are also accidentally damaged during inspections or recalibrations and are sometimes damaged when an employee physically forces the gauge face to point in a specific direction to see it better.

8. Steam


Many industrial processes use steam, often high-pressure steam. If this steam seeps into the gauge, it will result in damage to gauge internal components. This will eventually lead to gauge failure and even potentially dangerous loss of containment. WIKA’s exclusive Mini-Siphon system is the ideal solution to protect gauges from high-pressure steam. This innovative siphon system has an internal chamber that cools hot gases and minimizes the effects of surges and water-hammer on the gauge. Its sturdy design also helps damp vibration.

Avoid gauge damage from misapplication and mishandling errors by making sure everyone on your maintenance team has the appropriate training. WIKA will work with you to create a custom-designed FAST Instrument Safety Training. Beyond proper installation and maintenance, WIKA’s FAST engineers will teach your maintenance team to use gauges as predictive maintenance tools, helping them to spot issues before they develop into serious problems.

8 Most Common Reasons for Gauge Failures

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