This document discusses pyrometers, which are non-contact devices that measure the temperature of surfaces by detecting thermal radiation. It describes the principles of thermal emission based on blackbody radiation. Important parameters for accurate temperature measurement are discussed, including temperature range, emissivity, field of view, and spectral responsivity. Different types of pyrometers are outlined, such as fiber optic, single color, ratio, and multi-wavelength pyrometers. Applications of pyrometers include various industrial sectors like glass, nuclear, smelting, pharmaceutical, cement, power, chemical, and fertilizer industries.

1. LARGEST SENSOR MANUFACTURER

2. o What is Pyrometer?
o Theory of Thermal Emission
o Important parameters for accurate thermal emission
• Temperature range
• Emissivity
• The field of view(FOV)
• Spectral Responsivity
o Pyrometer types
• Fiber optic pyrometers
• Single color pyrometers
• Ratio type Pyrometers
• Multi wavelength Pyrometers
o Advantages
o Applications

3. o A pyrometer is a non-contacting
device.
o Pyrometer intercepts and
measures thermal radiation. This
device can be used to determine
the temperature of an object's
surface without contact to the
surface.

4. o The Thermal emission is based on the Black Body concept.
o Black Body is an object that absorbs all electromagnetic radiation
that falls onto it.
o No radiation passes through it and none is reflected.
o Electromagnetic radiation just depends on the temperature of
black body.
o The total emittance from a black body including all wavelengths is
directly proportional to the Fourth power of its temperature. This
temperature is called “Brightness Temperature, T”

5. o Temperature Range:
• Select right temperature span.
o Emissivity:
• Emissivity is defined as the ratio of
the energy radiated from a
material's surface to that radiated
from a blackbody (a perfect
emitter) at the same temperature
and wavelength and under the
same viewing conditions.
• The emissivity of a surface
depends not only on the material
but also on the nature of the
surface.

6. o The field of view (FOV):
• The FOV allows easy calculation of the minimum target size for a working
distance.
• A convenient measure is the distance to target ratio, e.g 100 :1 indicating
a minimum target of 10mm at a 1000mm measuring distance.
• To avoid errors that could arise from adjustments made during
operation, it is advisable to use an object size slightly larger than the
spot size.
• When the object does not fill the spot size completely, measuring errors
occur.

8. o Spectral Responsivity:
• The spectral responsivity range
should be selected so that the
emissivity of the surface is as high as
possible to maximize the
characteristic radiation from the
measurement object and minimize
the reflected ambient radiation. With
metals the emissivity rises in the
short wavelength band.
• Materials like glass, plastic etc should
be measured in special wavelength so
that, the material is impenetrable at
this wavelength band.
• Temperature of non metals can be
accurately measured in longer
wavelength band of 8…14 μm.

9. o Fiber Optic Pyrometers
 A fiber optics pyrometer consists of Optical head, Fiber optic cable
(single or multi fiber) and Electronic unit. The special construction
helps the pyrometer useful for
• High ambient temperature with no need of cooling system
(Ambient temperature up to 250°C).
• Strong electromagnetic field.
• Limited space for installation.
• Small spot size.
o Single Color Pyrometers
 Operate over a narrow range of Wavelengths
 Basically used for glass at 5.14µm. Metals can also be measured as
their rate of emissivity is high only in a narrow band.
 Spectral response of a particular device depends on the type of the
detector used.
 Works on selected wavelength range with the help of filters.

10. o Ratio radiation Pyrometers(two color Pyrometers):
 Measures the radiated energy of an object between two narrow
wavelength bands and then calculates the ratio of the two energies.
 This ratio is the function of the temperature of the object.
 Even if the object does not fully cover the spot the output signal will
not change.
 Temperature measurement is independent of emissivity, so the
errors caused by the emissivity variation, surface finish, and energy
absorbing materials between the pyrometer and the target can be
minimized or removed.
 Used for measuring high temperature.

11. o Multi wavelength Pyrometers
 Accurate temperature can be gained only with the knowledge
of surface emissivity.
 Multi wavelength pyrometer overcome many well known
difficulties of pyrometry.
 The instrument consists of Software which collect data from
numerous similar applications.
 Each measurement is analyzed and then temperature is
calculated.

12. • Ability to monitor temperature in situations where the object is
inaccessible or moving.
• Where the object may be contaminated or damaged by a contact
sensor.
• Where contact is not possible due to extremely high temperatures,
or where the object is electrically active.
• An Infrared Thermometer can be mounted remotely from the hot
target, enabling it to operate for long periods with minimal
maintenance.
• Very fast response time in tune of msec.

13. o Glass Industries
o Nuclear Industries
o Smelter Industry
o Pharmaceutical Industries
o Cement Industries
o Power Industries
o Non-Ferrous Industries
o Chemical and Fertilizer Industries

14. Tempsens Instruments (I) Pvt. Ltd.
B-188 A, Road No. 5, MIA, Madri
Udaipur - 313 003 (Rajasthan) INDIA
Phone : +91-294-3057700
Fax : +91-294-3057750
E-mail : info@tempsens.com
Website : www.tempsens.com
Temperature Sensing, Heating & Cables