Infrared Thermometers in Engineering

Newest technology assists fault finding in Aircraft systems. For AOPA Aug 2002

Technology is finding its way into all facets of our lives from the cars we drive to credit cards and ATM machines. In fact it would be almost impossible to work as efficiently as we do if it was not for technology.

An example of the latest computer technology making our daily lives easier and our jobs quicker and safer is in Aircraft maintenance where INFRA-RED thermometers have made amazing break throughs in accuracy and function with low costs.

These units are hand held "gun" style devices which can read the temperature of a surface from a distance instantaneously without touching the part! This makes determining clogged injectors or dead spark plugs a quick, easy and safe task. The "miss" on most engines can be tied to the right cylinder by measuring its temperature, usually the fault will signal itself by a lower temperature because the combustion is not correct. The safety factor is also important with cylinder temperatures well over 200 deg C the ability to measure the temperature from a distance will mean no more burnt fingers or arms. Similarly frozen brake pads that rub on the disk can be picked out in an instant. You can also calibrate oil or cht temp gauges.

This technology works by measuring the 'infra red energy ' emitted by most objects. In nature every object that is above absolute zero (approx -273 deg C) will emit some infra red radiation. This new technology originally developed for the defence industry, measures the frequency and strength of the infra-red radiation within a narrow band, a microprocessor then calculates the temperature of the target object. A range of small lenses focus the radiation so that only a small area of the surface of the object is read, this is typically a ratio of 8:1 where - when the infra-red thermometer gun is held at a distance of 80 mm, an area on the surface of the object of 10 mm is read by the unit & ther temp calculated & displayed. Also, at a distance of 800 mm an area of 100 mm would be read. The accuracy of these units has progressed to where, within a typical range of -20deg C up to greater than +400C the repeatability will be around 1 degree C.

The time saving and safety aspects of these infra-red units are very worthwhile and they are now available at under $300.