Sensors provide continuous predictive maintenance

Edited by the Engineeringtalk editorial team Jan 10, 2005

Over the last decade, the accepted preventive method of reducing the risk of switchgear failure has been periodic thermal imaging.

Over the last decade, the accepted preventive method of reducing the risk of switchgear failure has been periodic thermal imaging.

Indeed, it has become mandatory for certain "high risk" category organisations.

Although a significant step forward from shutdown and conventional inspection, it has significant shortcomings.

There are two major drawbacks in thermal imaging.

First, inspections are normally only periodic, (typically once or twice per year) due to the high costs/time involved.

The growing desire is to have thermal monitoring 24 hours a day 365 days a year ensuring potential problems are identified as soon as they develop, so reducing the risk of failures.

Secondly, thermal imaging is carried out externally to the switchgear enclosure.

As no infra-red device can "see" through solid objects, only components immediately adjacent to the external panel can be inspected.

These components cause the panel surface to heat via radiation and only this "image" is seen by the infra-red camera.

Thermal "windows" improve the situation, but still require direct line of sight to the target, anything hidden by internal structures or other components cannot be accurately inspected.

The answer is to have a system actually inside, directly and continuously monitoring all key components.

ExerTherm, is the only system of this kind; developed by QHi-Infrared it is based on small patented, plastic bodied, noncontact infra-red sensors, which are placed inside the enclosure continuously monitoring key components.

The sensors link back via data acquisition cards to PC and the easy to use software provides ongoing trend analysis.

Further protection is provided via two separate alarm levels per sensor (warning and alarm), which automatically activate in the event of preset temperature levels being exceeded.

ExerTherm has already been successfully installed with many major blue chip organisations in financial services, media, telecommunications, computer data centres, shipping, and large-scale manufacturing.

This new technology is suitable for new build and retro-fit.

Systems can be from as low as16 sensing points or up to several thousand.

ExerTherm can work as a stand-alone system or link with over 250 building management systems.

Although originally designed to monitor electrical switchgear, virtually all key plant can be continually monitored on the same system, using either IR, contact or air sensors.

Typical key plant would be pumps, motors, bearings, gearboxes steam traps, air/refrigeration systems; indeed anything which increases or decreases in heat as a symptom of malfunction.

The latest option is wireless telemetry and machine-to-machine communication (M2M).

A versatile range of GSM/GPRS products enable the monitoring of remote sites 24/7, from one central location.

Data collected can be transferred via network, intranet, Internet or cellphone: no more unnecessary routine visits to un-manned sites, only send out engineers when required.

These innovative devices can also be programmed to carry out I/O logic tasks, and can receive instructions; for example, in event of alarm on main pump, an instruction can be sent to switch off main pump and switch on auxiliary pump.

In transparent port mode, they can even access system information via RS232 input, acting like a virtual cable connection back to PC - but with no wires.

For those organisations where failure of critical power/plant results in significant downtime costs, continuous predictive maintenance can no longer be regarded as a luxury option, but should be seen as a necessity for critical risk management.