What Should be Monitored?

To at least some degree, it depends on the machine. Factors to consider might include how critical the system is, how maintenance intensive it is, and how the cost of preparing the infrastructure for monitoring compares to the potential benefits. Of course, not all systems will need all of the possible monitoring capabilities, but every system can benefit from collecting certain data. A good starting point for most systems is to ask what information would have been beneficial in the past. For most systems, the following are good conditions to monitor.

Temperature:

Monitoring the temperature of hydraulic fluid and critical components is essential. Excessive heat can lead to fluid degradation, accelerated wear of components, and reduced system efficiency. Monitoring temperature helps identify overheating issues, detect abnormal temperature fluctuations, and prevent potential failures.

Pressure:

Monitoring hydraulic pressure provides important insights into the system's performance and helps ensure it operates within safe limits. Pressure sensors are used to measure the pressure at various points within the system, such as pumps, valves, accumulators, and cylinders. Monitoring pressure helps detect pressure spikes, pressure drops, or inadequate pressure, which can indicate problems like leaks, blockages, or pump malfunctions.

Flow Rate:

Monitoring the flow rate of hydraulic fluid is essential for maintaining proper operation and detecting flow-related issues. Flow sensors measure the rate of fluid movement through the system. Monitoring flow rate helps identify restrictions, blockages, or excessive flow that may indicate valve malfunctions, clogged filters, or improper component sizing.

Fluid Level:

Monitoring the fluid level in the reservoir or other hydraulic components helps ensure an adequate supply of fluid. Low fluid levels can cause cavitation, aeration, or inadequate lubrication, leading to system malfunctions. Level sensors or sight gauges are commonly used to monitor fluid levels.

Filtration Efficiency:

Hydraulic systems rely on filtration to remove contaminants from the fluid. Monitoring the filtration efficiency helps ensure that the filters are effectively removing particles and maintaining the cleanliness of the fluid. Pressure differential gauges or dirt indicators across the filters can indicate when they need to be cleaned or replaced. Developing a filter replacement schedule becomes much easier when using the right sensors to monitor the filters.

Vibration:

Monitoring vibration levels in hydraulic systems can provide insights into the condition of rotating machinery, such as pumps and motors. Excessive vibration can indicate misalignment, bearing wear, or mechanical issues, which, if left unaddressed, can lead to failures or reduced equipment lifespan. Vibration sensors or accelerometers are used to measure and monitor vibration levels.

Fluid Contamination:

Hydraulic fluid contamination is a significant concern as it can cause damage to system components. Monitoring the level of contaminants, such as particles, water, or air, helps maintain the fluid's cleanliness and prevent premature component wear. Particle counters, moisture sensors, and air removal devices are commonly used for monitoring fluid contamination.

Operating Conditions:

Monitoring operating conditions such as load, speed, and actuator position provides a comprehensive understanding of the system's performance. These parameters can help identify abnormal conditions, deviations from expected behavior, or potential overloading situations. This can be especially helpful in systems required to maintain high levels of accuracy and precision.

By monitoring these conditions, hydraulic system operators and maintenance personnel can detect potential issues, identify root causes of problems, and take corrective actions in a timely manner. Regular monitoring and analysis of these conditions help ensure the reliability, efficiency, and longevity of the hydraulic system.
 

Importance of Monitoring Hydraulic Systems

Hydraulic systems are complex, consisting of numerous components such as pumps, valves, actuators, and fluid reservoirs. Regular monitoring of these systems is crucial to detect potential issues, prevent breakdowns, and optimize performance. Manual monitoring is time-consuming, prone to human error, and may not provide real-time data. Quite often, manual monitoring takes a back seat to other duties and in many cases simply never gets done. Therefore, automated monitoring solutions offer significant advantages.

Benefits of Automated Monitoring:

Real-time Data:

Automated monitoring systems collect and analyze data continuously, providing real-time information about hydraulic system performance. This enables prompt detection of abnormalities and timely intervention to prevent major failures.

Improved Reliability:

By monitoring key parameters such as pressure, temperature, fluid level, and flow rates, automated systems can identify potential issues before they cause significant damage. This leads to enhanced reliability and reduces the risk of unscheduled downtime.

Predictive Maintenance:

Automated monitoring allows for the implementation of predictive maintenance strategies. By analyzing historical data and identifying patterns, maintenance activities can be scheduled proactively, reducing costs, and minimizing disruptions.

Data Logging and Analysis:

Automated systems can record and store large amounts of data, enabling in-depth analysis of trends and performance patterns. This facilitates better decision-making and the identification of optimization opportunities.
 

Challenges of Implementing Automated Monitoring

Integration Complexity:

Integrating automated monitoring systems into existing hydraulic setups may require modifications or additional sensors. Compatibility issues and the need for specialized expertise can pose challenges during implementation.

Data Interpretation:

Collecting vast amounts of data is only valuable if it can be effectively interpreted. Analyzing and extracting meaningful insights from the collected data can be complex and time-consuming.

Cost Considerations:

Implementing automated monitoring systems can involve significant upfront costs, including sensor installation, hardware, software, and training. However, these costs are often offset by the long-term benefits of enhanced reliability and reduced maintenance expenses. Also, it is not necessary to do everything at once. We can start by monitoring critical circuits and gradually expand diagnostics to all circuits in all systems if we find it beneficial to do so.
 

Potential Solutions

Sensor Technology:

Utilizing advanced sensors capable of monitoring multiple parameters simultaneously can provide comprehensive insights into hydraulic system performance. These sensors should be rugged, accurate, and capable of transmitting data in real-time. Wired or wireless, many can transmit over Wi-Fi with several choices of input devices. If wireless, they can use either battery power or a local power supply.

Data Analytics:

Implementing sophisticated data analytics tools can help process and interpret collected data, providing actionable insights to optimize hydraulic system performance. While many facilities already have several sensors in place, most of them are to provide information for logic systems. Few are installed just for data collection and analysis.

Remote Monitoring:

Leveraging remote monitoring capabilities allows for real-time data access from anywhere, enhancing the ability to respond promptly to critical events and anomalies.

Automatically monitoring hydraulic systems for reliability is crucial to maximize performance, prevent failures, and minimize downtime. Through the implementation of automated monitoring systems, industries can benefit from real-time data, improved reliability, predictive maintenance, and data-driven decision-making, especially while troubleshooting.

While challenges such as integration complexity and cost considerations exist, advancements in sensor technology and data analytics provide potential solutions. By embracing automated monitoring, industries can ensure the longevity and efficiency of their hydraulic systems, leading to increased productivity and reduced operational costs.

 

Where to Start

Pressure and flow monitoring are two essential aspects of hydraulic system maintenance and troubleshooting. If there are budgetary constraints or if the user simply wants to build a total monitoring system over time, these two are by far the most important. These monitoring techniques provide valuable information about the performance and health of the system, allowing for early detection of potential issues and ensuring optimal operation.

Pressure Monitoring:

Pressure monitoring involves measuring the pressure within the hydraulic system at various points. This allows operators to assess the system's overall health and identify any abnormalities. Pressure gauges or transducers are typically installed at critical locations, such as the pump outlet, valve ports, accumulators, and actuator ports.
 

Key aspects of pressure monitoring include:

System Pressure:

Monitoring the overall system pressure helps ensure that it falls within the recommended range for safe and efficient operation. Deviations from the desired pressure can indicate problems such as blockages, leaks, or pump or accumulator malfunctions.

Differential Pressure:

Differential pressure is the difference in pressure between two points in the system. Monitoring differential pressure across filters, valves, or other components helps identify clogged or failing elements.

Peak Pressure:

Monitoring peak pressure levels can help identify potential overloading conditions, which may lead to component failure or system damage.
 

Flow Monitoring

Flow monitoring involves measuring the rate of fluid flow within the hydraulic system. This information is crucial for assessing the system's performance, detecting blockages, and ensuring adequate lubrication and cooling. Few systems have any way to measure flow rates at critical points. Many designers seem to believe that measuring pressure is enough, but pressure is only part of the story. For instance, if an actuator moves too slowly, is it bypassing or is the flow restricted somehow? A pressure gauge can’t tell us this.

Key aspects of flow monitoring include:

Flow Rate:

Monitoring the flow rate helps ensure that the hydraulic system is providing sufficient fluid to meet the operational requirements. Low flow rates can indicate a blockage or a problem with the pump or accumulator, while high flow rates may suggest excessive wear or a malfunctioning control valve.

Flow Direction:

Monitoring the flow direction can help identify issues with valve operation or fluid circuitry, ensuring that the fluid is flowing in the intended direction. This can identify components such as check valves and pressure controls that have stuck open.

Fluid Temperature:

Monitoring the temperature of the hydraulic fluid is vital for detecting potential overheating issues. Elevated temperatures can indicate inadequate cooling or excessive friction within the system.

By continuously monitoring pressure and flow, operators can detect anomalies, diagnose problems, and take appropriate actions to prevent system failures, reduce downtime, and increase the overall reliability and efficiency of hydraulic systems.
 

Temperature Monitoring

Monitoring temperature on hydraulic systems is an essential aspect of ensuring their safe and efficient operation. Hydraulic systems use fluids under high pressure to transmit power and control the movement of various mechanical components. Monitoring the temperature helps in detecting potential issues, preventing system failures, and maximizing the lifespan of hydraulic fluid and components.

For the most part, when hydraulic components wear, they usually leak. If they are leaking onto the floor, that is pretty obvious. More often however, they leak internally, or bypass, which can go unnoticed for quite some time.

There may be no visual signs of wear until the component suddenly no longer performs satisfactorily, but bypassing does have one common characteristic – a temperature gain across the component. This is because any leak, whether internal or external, results in a pressure drop that does no useful work.

Any pressure drop that does not do any work generates heat. Thus, a component that is worn will have an abnormal temperature gain. We must monitor temperature because, in order to spot an abnormal gain, we must have some idea what “normal” is.

Temperature Sensors:

Temperature sensors are used to measure the temperature of the hydraulic fluid. The most common type of sensor is the resistance temperature detector (RTD) or a thermocouple. These sensors are placed at strategic points within the hydraulic system, such as the reservoir, pump, valve blocks, or critical components.

Sensor Placement:

The location of temperature sensors is crucial for accurate monitoring. Sensors should be installed in areas where temperature changes are most likely to occur, such as near high-pressure zones, close to heat-generating components, or within the hydraulic fluid flow path.

Sensor Calibration:

Before deployment, temperature sensors need to be calibrated to ensure accurate readings. Calibration involves comparing the sensor's output with a known temperature reference and adjusting it if necessary. This step helps to eliminate any systematic errors in the sensor's measurements.

Data Acquisition:

Temperature sensors are connected to a data acquisition system, which captures and records the temperature readings over time. This can be a dedicated monitoring device or part of a larger control system. The data acquisition system may include analog-to-digital converters to convert the sensor's analog signals into digital data that can be processed and analyzed.

Monitoring and Analysis:

The acquired temperature data is continuously monitored and analyzed to detect any abnormalities or trends. Thresholds or alarm limits can be set to trigger alerts if the temperature exceeds safe operating limits. Analyzing the temperature patterns can provide insights into the performance of the hydraulic system, identify potential issues like overheating, and help plan preventive maintenance.

Maintenance and Intervention:

Temperature monitoring enables proactive maintenance practices. If temperature readings indicate abnormal conditions, such as excessive heat, it may indicate a problem like a failing pump, blocked filter, insufficient cooling, or excessive friction. Maintenance personnel can take appropriate measures to address the issue before it escalates and causes system failure.

 

 

Benefits of Temperature Monitoring in Hydraulic Systems

Early Detection of Issues:

Monitoring temperature helps detect anomalies and potential problems in hydraulic systems. Unusual temperature spikes or prolonged high temperatures can indicate issues like component wear, fluid degradation, contamination, or insufficient cooling.

Preventing System Failures:

By identifying problems in their early stages, temperature monitoring allows for timely maintenance or repair, preventing catastrophic failures that could result in expensive downtime and repairs.

Extending Component Lifespan:

Excessive heat is detrimental to hydraulic components, leading to accelerated wear and reduced lifespan. Monitoring temperature helps ensure that components operate within their specified temperature range, promoting longevity and reliability.

Performance Optimization:

Temperature monitoring provides valuable data for analyzing system performance and identifying areas for improvement. It helps in optimizing cooling strategies, fluid selection, and overall system efficiency.

Monitoring temperature in hydraulic systems is a critical aspect of ensuring their safe and efficient operation. By using temperature sensors, data acquisition systems, and analysis techniques, potential issues can be detected early, system failures can be prevented, and the lifespan of hydraulic components can be maximized.
 

Sensor Interfacing

Many PLC systems already support data storage and analytics, so chances are that a machine can begin logging by doing nothing more than installing the sensors and configuring the I/O ports. Many users, however, prefer to make continuous monitoring a separate function so that access can be controlled. Also, not all PLC software speaks the IoT protocols to communicate with newer in-plant infrastructure.

Interfaces such as SensoNODE™ can provide both local and cloud-based interface solutions offering features such as customizable dashboards, email/SMS alerts, graphing, statistics, and much more. Many of the individual sensors offer a wireless range up to 1,000 feet (easily extended by repeaters), and the cloud-based interface allows access to anywhere with internet access.

Can’t this information all be gathered and recorded manually? Of course, it can. But it won’t be.

In three decades of instructing and consulting throughout the United States and beyond, I have provided customized reliability and preventive maintenance forms to hundreds of industrial plants designed to gather and record exactly this type of information. Not once have they been utilized for very long before other tasks have taken over their priority. With automatic continuous monitoring and recording, the data actually gets recorded and is available when it is needed to avoid downtime and unnecessary component replacement. Of all the benefits, this is the greatest.