Frequently
Asked Questions
What
is infrared radiation and how does it relate to problem detection?
Everything
that has a temperature emits infrared (IR) radiation . The amount
of IR radiation emitted at a certain wavelength, from the surface
of an object, is a function of the object's temperature. This
is a very important concept, since it implies that one can calculate
the temperature of an object by measuring the infrared radiation
emitted from it. Detectors in todays infrared imagers translate
incoming IR radiation patterns from an object into visual maps
that co-relate image intensity or colour to the amount of IR
radiation recieved from that object. The amount of radiation
receieved, along with other parameters, is used to calculate
the actual surface temperature of the target object. The detectors
are extremely sensitive to minute temperature differences and,
under the control of a trained thermographer, temperature calculations
are accurate and reliable.
What
is a thermal anomaly?
Any
disequilibrium or gradient in real or apparent surface
heat distribution and/or magnitude, with respect to a uniform
reference temperature, which should not exist under normal or
ideal conditions.
What
is emissivity?
Emissivity
is a term used to describe how effective a substance is at emitting
electromagnetic
radiation at a particular wavelength. It not only depends on
intrinsic thermophysical properties of a particular substance,
but also on an objects surface characteristics, and the direction
the radiation leaves this surface. Determining material emissivities
is important when deducing its temperature from the amount of
infrared radiation it emits.
What
are the advantages of using infrared imaging for temperature
measurement?
1.
Measures temperature without contacting object.
2.
Minimises maintenance downtime because equipment does not have
to be taken offline for
inspection.
3.
Detects fault conditions before they lead to outright failure.
4.
Will not deface or destroy the product being inspected.
5.
Takes temperature measurements within milliseconds rather than
seconds as with contact methods.
6.
Can be used to study and analyse transient phenomenon or moving
objects.
7.
Can measure the temperature of irregularly shaped objects.
8.
Measures through hazardous atmosphere.
9.
Does not act as a heat sink as do contact methods.
10.
Collects large amounts of data in a short period of time and
can store this data for future reference and trending.
What
is Infrared Radiometry?
Radiometry
is the study of the physical principles behind how electromagnetic
radiation is detected and measured. It also includes information
on the design of different radiation detectors and the associated
science of optics. The sub-field of radiometry that involves
calculating temperature using the infrared part of the electromagnetic
spectrum is termed Infrared Radiometry.
What
is Infrared Thermography?
Infrared
Thermography (IRT) is the applied discipline of combining infrared
radiometry, heat and mass transfer theory, and thermodynamics
for the purpose of qualitative and quantatative non-destructive
testing.
Who
is interested in using Infrared Thermography?
Property
managers, engineers and facility managers of all types are always
concerned with the condition of buildings and equipment under
their care. All would agree that proper maintenance, management
of energy resources and quality
of construction are necessary for optimising safety, performance
and cost savings.
Veteranarians
and doctors are using infrared imaging to analyse surface thermal
patterns that are symptomatic of an underlying ailment or condition.
Nowhere is the value of clinical
IRT for animals more evident than when its applied to the
care of horses. Many minor injuries to muscle tissue may go
unnoticed until the problem is more severe. However, infrared
imagers used today can pick up the smallest change in temperature
as a result of increased blood flow to damaged tissues. In this
way IR imaging aids the expert trainer in caring for the horse.
Manufacturers
concerned with non-destructively testing product quality and
performance, are also among those employing, infrared radiometric
technologies. An automobile manufacturer might use IRT to measure
the real-time thermal dynamics of a prototype engine block or
a plastics manufacturer might be interested in monitoring its
extrusion process. Many industrial processes implicate the use
of IRT where temperature and heat flow are a useful indicators
of how a process is operating.