| Heitronics has been very active within
the lighting industry over the past 20 years. Major users
of our products include Osram-Sylvania, Philips and General
Electric. Many of the features that are now standard in
the Heitronics product line are a result of being active
in this area.
Why do Heitronics products meet the requirements found
within the Lighting Industry?
1) The detector used by Heitronics is a Heitronics design.
It is a Lithium Tantalate pyroelectric crystal which
does not drift in its detectivity.
Benefit: An inherently stable pyrometer. There
is no need for an automatic internal correction feature
which is offered by a reputable competitor.
KT19 long term stability is better than 0.0001( reading
in K) per month.
2) The pyroelectric detector requires the challenge of
chopping the radiation signal in order to make the detector
work. Heitronics has used chopper motors in every commercial
instrument since the first pyrometer design in 1959. The
chopper motor used in KT19 series is a Heitronics design
which offers an MTBF of 9 years.
Benefit: The resulting use of AC electronic circuits
which are more stable than DC circuits. Accuracy is ±(0.5°C
+ 0.007( target temp. - housing temp.)).
3) Pyroelectric based pyrometers are capable of responding
faster than competitive thermopile based pyrometers. (The
Heitronics response time definition is the time required
to respond to 90% of a step change in temperature. Multiply
this response time by x 1.5 to approximate the 99% value.)
Benefit: KT19 series has adjustable response time
to as fast as 30ms.
4) The availability of 35 standard lenses, 10 standard
possibilities of positioning the lenses out in front of
the detector and 4 different detector aperture sizes provides
close to a thousand fixed focus options. Combine the focus
options with high quality lenses, a very rugged way of precisely
fixing the lens in front of the detector and the result
is a very high distance to target size ratio. (Heitronics'
definition of spot size is for the area where 95% of the
total radiant signal comes from.)
Benefit: Distance to target size ratios for the
4.9 to 5.5 microns spectral band can be delivered as high
as 220:1, for the 400 to 2500°C temperature range which
allows viewing small targets at a safe distance from heat,
silica dust and moving machinery.
5) KT19 series offers three ways in which to help aim
the instrument; through the lens visual sighting, laser
illumination of the target center or LED illumination of
the target area.
The precise way in which Heitronics' production staff
aligns the combination of visual, internal light source
and infrared target area ensures the coincidence of these
three parameters.
Benefit: The assurance that when careful aiming
is done on small and specific target areas, the infrared
measurement will be made from where it is wanted.
6) KT19 series is 1990's technology using the latest available
surface mounted device components and microprocessors.
Benefits: Complete programmability is available
via the rear keyboard or via a bi-directional digital interface.
A digital display is incorporated on the instrument's rear
face. All electronics are built within the one compact sensor
housing which saves space and installation expense.
7) The suggested 4.9 to 5.5 microns spectral response
of KT19.42 corresponds with the glass and quartz absorption
band. Viewing through flames or making the temperature measurement
of the glass surface while under the direct presence of
flame is made with a minimum amount of influence. We suggest
to use an emissivity setting of 0.96 for this spectral response.
Many other spectral responses are available for applications
including low temperature glass measurements and metal surfaces.
Benefits: Use of Heitronics pyrometers is possible
virtually anywhere within the lamp plant.
8) KT19 includes as standard features, an external secondary
temperature sensor input or can be programmed by a given
value for compensating for the contribution of a high temperature
background as seen via the 4% reflection off of the glass
target area.
Benefit: Measurement of glass surfaces within lehr's
can be made while correcting for the contribution of radiation
from within the lehr.
9) An effective air purge fitting design ensures that
the lens can remain clean when the recommended 5 psi of
nitrogen is connected.
Benefit: The major cause for an apparent
change in instrument calibration can be eliminated by keeping
the lens clean.
10) KT19 housing design is water-tight, dust-tight and
shielded from electromagnetic interferences. It is available
as standard to withstand up to 60°C ambients and perform
to all published specifications. It is also available in
a coolable housing version for handling up to 150°C
ambients.
Benefit: It survives the conditions that the lighting
industry presents.
Selected instrument specifications which have been applied
to Lighting Industry applications:
Heitronics Model KT19.42, 4.9 to 5.5 microns spectral
response
Use: Surface measurement of quartz and glass during
lamp fabrication and research
Features: Fast response time ( 30ms ); high optical
resolution ( 220:1 distance to target ratio, i.e.: 1mm dia.
@ 203mm distance; 2.5mm dia.@ 550mm distance ); wide temperature
range 150 to 1600°C or 400 to 2500°C; long term
stability better than 0.0001 (reading in K ) per month;
through the lens sighting, laser sighting or LED sighting;
linearized analog outputs and bi-directional digital interface
Benefits: View through flame, measure clear glass*/quartz
surface to depth of 0.05mm @ 1400°C; proven to repeat
measurements of 2100°C with 30ms response time to ±6°;
high repeatability allows output signal to be put into a
control loop
Heitronics ModelKT19.43, 7.5 to 8.2 microns spectral
response
Use: surface measurement of quartz and glass during
lamp fabrication and research
Features: Fast response time ( 30ms ); wide temperature
range 200 to 1200°C; long term stability better than
0.0001 (reading in K) per month; through the lens sighting
and/or LED or laser sighting; linearized analog outputs
and bi-directional communications
Benefits: Measure clear glass*/quartz surface to
depth of 0.01 mm @ 700°C; high repeatability allows
output signal to be put into a control loop, emissivity
= 0.98 for this spectral response
Heitronics Model KT81R, ratio of two wavebands
between 0.7 to 1.2 microns
Use: Measurement of tungsten and molybdenum for
research and production
Features: Ratio of two wavelength technique permits
the measurement of metals with low and potentially changing
emissivity; through the lens sighting, adjustable aperture
to block radiation from unwanted surrounding sources, controlled
detector temperature plus chopped radiation technique provides
highest degree of measurement stability while reducing the
dependency of requiring a greybody target, linearized analog
output direct from sensor, temperature range, cover 700
to 3600°C
Benefits: Target need not fill the field of view
( 50 micron tungsten wire @ 1000°C can be measured with
focus of 10mm diameter ), views through quartz windows found
on hydrogen sintering furnaces; target can wander within
the field of view but because of the chopped radiation technique,
if the target wanders out of the field of view, a high reading
will result for a duration equal to the response time; additional
signal conditioning hardware available for handling targets
which wander out of the field of view
Heitronics Model KT81S, 0.7 to 1.2 microns spectral
response
Use: Measurement of tungsten and molybdenum for
filament research
Features: High optical resolution for viewing 0.005
inch diameter @ 4 1/8 inch distance, spectral response permits
viewing through glass and quartz envelopes; 10 millisecond
response time, temperature ranges cover 1100 to 3450°C;
calibration accuracy ±3°C plus 0.5% of target
temperature; linearized analog output direct from sensor
Benefits: Measurements made on an electronic basis
as compared to a human basis as previously found
on disappearing filament optical pyrometers; views through
quartz and glass envelopes
* Reference: Theory and Practice of Radiation Thermometry,
DeWitt and Nutter, 1989 |
