By Chris Hansford, Hansford Sensors
A range of vibration sensors and monitoring techniques are now available that can extend the operating life of automated machinery beyond recommended maintenance intervals and, at the opposite end of the scale, identify rapid increases in machinery vibration that could lead to a catastrophic failure. These devices and techniques also enable operators to satisfy the ever-more robust regulations imposed regarding health and safety, which have made the use of vibration sensors in non-safe areas a prime requisite. So, far from being an expensive option, the use of vibration monitoring can enable companies to operate with enhanced performance, reduced downtime and in accordance with health and safety legislation.
Mounted in a number of key positions on mechanical equipment, vibration sensors offer the potential for continuous monitoring and analysis, an inexpensive option when balanced against the potential cost of downtime on an automated line, and when condition monitoring measures are in place to detect factors such as vibration, machine downtime can virtually be eliminated. There are two main types of industrial accelerometer: AC accelerometers and 4-20mA accelerometers. AC accelerometers are typically used with data collectors for the vibration monitoring of more critical/complex machines, such as gearboxes and turbines. Meanwhile 4-20mA components are commonly used with PLCs to measure lower value assets, monitoring such levels as pump vibration, motor vibration and machine vibration.
Once you have specified the right equipment and installed carefully in order to yield the most repeatable and consistent measurement of vibration, machine reliability data can easily be analysed to predict potential problems before they occur. Increases in machinery vibration indicate deteriorating operating conditions, such as wear or misalignment, and vibration sensors can identify these changes swiftly and with exceptional reliability. A typical technique in vibration monitoring has been to examine the individual frequencies within the signal that correspond to certain mechanical components or types of malfunction, such as shaft imbalance or misalignment, so that analysis of this data can identify the location and nature of a given problem.
To specify a vibration accelerometer correctly, engineers need to consider the vibration level and frequency range to be measured, weight or fitting restrictions and environmental conditions, such as ambient temperatures, the presence of moisture, chemicals or potentially explosive atmospheres. The best approach is to work closely with a supplier that has appropriate industry experience and knowledge. As more and more companies become increasingly dependent on physical rather manual assets, automation brings a new set of challenges.
As an essential tool for industry, delivering benefits that include increased productivity, consistent quality and cost reduction, automation has the potential to boost productivity and efficiency, not to mention product quality, but it can only do so if the plant is adequately monitored and protected. It therefore makes good business sense to protect automated production lines with vibration monitoring equipment. About Hansford Sensors: the International Centre of Excellence for Vibration Monitoring Hansford Sensors Ltd specialise in the design and manufacture of accelerometers for monitoring vibration and temperature levels of industrial machinery, playing a key part in the role of predictive maintenance.
Products include intrinsically safe models for approved use in Group I (Mining) and Group II (Petrochemical). Hansford Sensors Ltd also supply multi-sensor switch boxes, vibration sensor modules, portable vibration meters, accessories for sensors, vibration condition monitoring protection systems and custom built vibration sensors.