Condition Monitoring: Everything You Need to Know

Used across a wide range of industries and sectors, condition monitoring (CM) is fundamental to mechanical performance. The term describes the process of monitoring mechanical parameters such as vibration, acoustic emissions and temperature, with the underlying goal to detect changes that could indicate a potential fault or malfunction.

From power trains and distillation reactors used in the oil and gas industry, to pumps, presses and other small parts found in automotive manufacturing factories, CM techniques are used to maintain a wide range of machinery.

Industrial machines generally operate in demanding environment, meaning deterioration is a constant risk. By keeping tabs on the condition and performance of mechanical equipment, operators can reduce unplanned downtime and optimise output and efficiency.

Want to know more about condition monitoring and the keynote role it plays across a wide range of machine-dependent industries? Read on for a complete overview of condition monitoring, how it works and the different parameters used to track mechanical performance.

How does condition monitoring work?

Condition monitoring involves regularly inspecting the status of machinery during normal operating conditions. Parameters of interest depend on the type of machinery being monitored, with specialised sensors used to acquire data. Advanced software programs are used to process data acquired by sensors and compare it with baseline figures and trends, as well as representative data from analogous machines.

Condition monitoring and predictive maintenance

Condition monitoring is part of a wider field called predictive maintenance, which relies on data to track the condition of equipment and machinery. This data is used to schedule maintenance and prevent mechanical issues before they materialise. Ideally, predictive maintenance prevents the need for reactive maintenance, which occurs after a mechanical failure has arisen and is generally more expensive.

What about routine and time-based preventive maintenance?

Some operators rely exclusively on routine or time-based preventive maintenance to identify and repair issues before they cause problems. While this is better than omitting preventive maintenance altogether, a predictive approach offers greater benefits.

Actively monitoring mechanical parameters allows operators to pinpoint exactly when and where a problem might arise. Unlike routine or time-based preventive maintenance, repairs are only performed when an issue is identified. This translates to significant savings for mechanical operators. Not to mention considerable benefits in the form of heightened efficiency and output.

From railways to refining: The history of condition monitoring

The history of condition monitoring can be traced to the 1850s, when railway maintenance engineers relied on small hammers to inspect and monitor the conditions of locomotive wheels. By tapping the wheels with the hammer and analysing the sounds, engineers were able to assess the state of each individual wheel. A wheel in good condition would emit a high-pitched ring, while compromised wheels with cracks sounded dull and flat.

Today, the same concept has evolved into one of the most valuable tools used by mechanical operators. Advances in electronic sensors and software have reimagined the limits of condition monitoring and made it an instrumental tool used across a wide range of industries.

Modern condition monitoring techniques

Operators rely on a range of different techniques and diagnostic systems to collect condition monitoring data. Below, we highlight some of the most useful techniques used to monitor different parameters and tack the condition of mechanical equipment.

• Oil sampling and analysis

Oil sampling and analysis generally involves extracting samples from machinery and having it analysed in offsite laboratories. Analysing the state of the oil is an important part of optimising mechanical performance and preventing costly repairs.

• Acoustic emissions

Over the past decade, acoustic emission has emerged as an invaluable CM tool. While monitoring acoustic emissions does require significantly more data storage than other parameters due to the high frequencies the sensors operate on, it’s a useful way to detect faults in the earliest stages.

• Vibrations

Vibration monitoring is one of the oldest and most effective parameters used in condition monitoring analysis. As well as helping detect operational irregularities, CM vibration data can be used to identify the root cause of the problem. Accelerometers are used to generate real-time data and monitor vibration across a wide frequency range. This makes detecting mechanical issues such as misalignment, bearing wear, loose components and gear tooth fatigue.

• Infrared thermography 

Infrared thermography, also known as temperature monitoring, is used to detect abnormal heat emitted by machinery. This parameter is measured using a range of techniques, ranging from static infrared cameras to sensors that actively scan machinery to generate real-time data. As well as maintaining the health of heavy-duty equipment, infrared thermography is useful for preventing electrical failure and minimising the risk of industrial fires.

• Corrosion

Unlike other parameters that rely on electronic sensors, visual inspection is the most widely used technique for monitoring mechanical corrosion. That said, parameters such as pH levels, pressure, flow rate velocity and electrical resistance can also be used to detect corrosion. These parameters rely on sensors and probes to measure changes and detect potential issues.

• Ultrasound analysis

Effective and cost-efficient, ultrasound analysis is used to measure sound pressure waves and detect irregularities. This parameter is usually combined with vibration monitoring techniques, which offer more detail on the root cause of the irregularities.

With the exception of some visually-based parameters, ultra-precise sensors are used to measure each of these different markers in real time.  

The role of predictive maintenance engineers (PdMs)

Across the sector, the experts who monitor and track mechanical changes are called predictive maintenance engineers. These mechanical ‘doctors’ use data to diagnose issues in the earliest stages. This allows operators to reduce mechanical downtime and avoid catastrophic failures, while keeping maintenance and repair costs as low as possible.

The benefits of condition monitoring

Below, we take a look at some of the benefits of condition monitoring and explore how investing in sensors, software and analysts generally pays for itself.

• Minimising mechanical downtime

The definitive goal of condition monitoring is to minimise mechanical downtime. From oil and gas refineries to food production factories, optimising output and efficiency has a direct impact on profits.

• Reducing maintenance costs

The ability to track mechanical performance and identify issues before they occur translates to big savings for operators. Instead of scheduling routine or time-based preventive maintenance, CM ensures repairs are only carried out when necessary.

• Extending the life of machinery

Monitoring parameters like vibration and temperature allows operators to significantly extend the life of machinery. Repairing issues as they arise prevents further damage from occurring and keeps machinery in its prime for longer. Machinery and infrastructure is a huge expense for operators, meaning condition monitoring usually pays for itself.

Condition monitoring applications

Now we know more about condition monitoring, let’s take a look at the different applications it’s used for.

• Industrial plants and manufacturing facilities

From oil refineries to car manufacturing plants, condition monitoring is fundamental to the industrial sector. Data collected by CM sensors is used to track the performance and condition of electric motors, pumps, fans, gearboxes and other moving parts.

• Pulp and paper industry

The global pulp and paper industry is another industry heavily reliant on condition monitoring. This type of preventative maintenance is used to keep chippers, refiners, blowers and other heavy-duty pulp and paper manufacturing machinery working at its best.

• Steel, iron and other metals

Machines built to handle heavy-duty raw materials such as steel and iron must be fastidiously maintained. Condition monitoring is central to the metal industry, with sensors used to detect irregularities in conveyor belts, galvanisation plants, stack reclaimers, rolling mills, continuous casters and other complex machines. Condition monitoring is also used to keep tabs on smaller mechanical elements, including fans, pumps and gearboxes.

• Automotive and mechanical repairs

Mechanics and automotive engineers rely on condition monitoring to keep vital equipment in top working order. Sensors are used to detect even the smallest performance changes in large mechanical systems such as air handling units and wind tunnels. CM is also useful for monitoring the status of pumps, presses and other smaller equipment.

• Power generation

Power generation is a mammoth industry and condition monitoring plays an important role in maximising output and efficiency. From gas and steam turbines to water pumps, sensors and software are used to track and analyse a range of parameters in power generation plants, including vibration and temperature. Data is used to detect minor issues before they escalate, allowing operators to maximise uptime.

• Cement

Cement is the backbone of the building and construction industries. A range of constituents are used to create the durable binding material, including limestone, clay, chalk, shale, sand, marl and iron ore. These constituents are incredibly tough on mechanical machinery, making continuous condition monitoring an important part of the cement industry.

CM data allows cement plant operators to detect problems early, schedule maintenance accordingly and reduce downtime. This ensures specialised cement machinery such as crushers, separators, conveyor belts, raw mills, elevators and blowers continue to operate at maximum efficiency.

The future of condition monitoring

The condition monitoring sector is continually evolving, with new techniques and technologies making it easier than ever to track mechanical performance, detect irregularities and schedule repairs. This maximises output and efficiency, extends the longevity of machines and translates to profits.