|
Infrared Thermometer
Information
|
|
|
The most basic design consists of a
lens to focus the infrared (IR) energy on to a detector, which converts
the energy to an electrical signal that can be displayed in units of
temperature after being compensated for ambient temperature variation.
This configuration facilitates temperature measurement from a distance
without contact with the object to be measured. As such, the infrared
thermometer is useful for measuring temperature under circumstances where
thermocouples or other probe type sensors cannot be used or do not produce
accurate data for a variety of reasons. Some typical circumstances are
where the object to be measured is moving; where the object is surrounded
by an EM field, as in induction heating; where the object is contained in
a vacuum or other controlled atmosphere; or in applications where a fast
response is required.
 Common
Questions When Using an Infrared Thermometer:
Infrared pyrometers allow users to measure
temperature in applications where conventional sensors cannot be employed.
Specifically, in cases dealing with moving objects ( i.e., rollers, moving
machinery, or a conveyor belt), or where non-contact measurements are
required because of contamination or hazardous reasons (such as high
voltage), where distances are too great, or where the temperatures to be
measured are too high for thermocouples or other contact sensors.
| Infrared
Tutorial |
 |
 |
|
What is the
history of IR? |
|
|
 |
 |
 |
The Royal Astronomer Sir William
Herschel discovered "Dark Heat" radiation in 1800.
In 1880 the term "infrared" was coined. Samuel Langley invented
the bolometer that measures variations of resistance when heated.
In 1901 a bolometer could detect a cow at 400 meters.
After World War II, many countries invest huge amounts of money in
IR for military application.
In 2002 Radiant Innovation, has designed the most compact; most
long battery life (70hours continuous use) and the most affordable
IR Thermometer by the proprietary SoC & Infrared Technology, use
MEMS based; advanced Thermal Sensor. |
|
 |
 |
 |
 |
|
|
What is
infrared radiation (IR)? |
|
|
|
|
|
|
| IR
just like any light ray, is an Electromagnetic
Radiation, with lower frequency (or longer wavelength)
|
| Anything above absolute zero (-273.15
degrees Celsius or 0 degrees Kelvin), radiates in the infrared.
Even ice cube, snow, your refrigerator emit infrared. |
|
|
|
|
|
|
|
|
|
Your eyes are design for Sunlight, 2
kinds of species are identified to be able to detect IR: some
rattle snake & beetle. But you still can sense the IR by your
skin:Beside a campfire, you can feel the warmth from the IR.
When your car is baked by sun , you start the car, turn on
Air-Con, the air is cooled,
But you still feel Baking-Hot!, that's IR come from the interior
of the car, reaching your sensor (skin).
You may use IRT to learn that the radiation temperature in your
car can reach 80degC! |
|
|
|
|
|
|
|
|
|
Believe or not, Quantum physics is the
key theory:
the total radiation energy is proportional to the fourth power of
the absolute temperature (Stefan-Boltzmann Law)
Wien Displacement Law: the product of the peak wavelength and the
temperature is found to be a constant.
Wien get the Nobel Prize for Physics for the year 1911.
These are the major earthquake in physics, after that Classic
Physics crashed, Quantum Physics flourish. |
|
|
|
|
|
|
|
|
|
|
|
As I
remember, usually IRT are much larger than this one? Accuracy is
compromised? |
| |
IRT were much larger, but ZyTemp
is as small as the "battery of some large IRT".
Accuracy is not compromised, each device has a test report in our
database, which is traceable by the serial number.
These test follow the disciplines of "ASTM E1256.Test Methods for
Radiation Thermometers (Single Waveband Type)"
Under Development:
COC on Web
You can check the accuracy test report of the very IRT in your
hand by visiting our web site www.ZyTemp.com and entering the
serial no.
Some model (TN1xx-tr) has a hardcopy test report right in the
package.
RII is the only manufacturer who can provide free test report via
internet.
In terms of accuracy, size doesn't
matter. |
|
|
Can IRT
measure air temperature? |
| |
No and Yes.
No, because Air do not emit infrared, the emissivity is too low to
be detected.
Yes, because you can pointing the IRT to anything that has the
SAME temperature as the air:
Outdoor: leaf , tree, grass (under sunshade) has the same
temperature as the air
Indoor: your desk, a piece of paper, has the same temperature as
the air.
The key to get "Air temperature" is to measure "anything which
should have the same temperature as the air"
|
|
|
Can I measure
the body temperature of an Ant by IRT? |
| |
You can pointing the IRT to an Ant
on your desk, but what you get is an average temperature of the
Ant & the Desk
because the Field Of View of the IRT is much larger than the Ant.
But, if you can get 10,000 of ant, on your desk, which can cover
the whole FOV of the IRT,then
YES, you can measure the body temperature of Ant.
This FOV issue, is a
key to get correct reading from IRT.
|
|
|
How far ? |
| |
I can measure temperature of a wall from
5meter? Temperature of a mountain from 1km?
We are using the 8um to 15um infrared, the atmosphere is almost
totally transparent for this band.
At 100meter, no rain, no fog condition, IRT is very accurate.
At 1km, you need some physics background to correct the reading.
see [Theory and Practice of Radiation Thermometry] by D.P. DeWitt,
chapter 3. |
|
|
Can the IRT
operated in complete darkness? |
| |
Yes, that's why DOD & military are so
interested in IR.
In fact, the early IR technology are developed by military fund. |
|
|
Can the IRT
penetrate a building, measure what's inside? |
| |
In real life, No. It can be done only in
the movie. |
|
|
But I
remember IR can penetrate something? |
| |
IR can penetrate PE film (for example: a
complete dark garbage bag), Silicon, Gemanium.
You can hide something warm behind a PE film (your hand), the IRT
can detect the presence of the object. |
|
|
Now I can
measure the body temperature of a fish in my aquarium? |
| |
No, water & glass is transparent for
visible light only, but for IR, it's completely "opaque", all IR
from the fish can't penetrate the water, so you are only measure
the temperature of the glass.
How about my pet's temperature? by pointing IRT to your dog, you
get the temperature of the fur. What you see is what you got. |
|
|
How do I
know, my IRT is still accurate? |
| |
Calibration of IRT is extremely
sophisticated, that's why IRT were so expensive. (not any more!)
RII develop his own proprietary CCE(Continuous Calibration
Equipment), which can calibrate 96pcs of IRT at the same time, at
different temperatures, in a continuous, high throughput
operation.
The Cycle time is also reduced by a special prediction algorithm.
RII are ISO9001 certified.
Our Infrared Ear Thermometer can conform with the ASTM E1965's
stringent requirement: +/-0.2degC
If still in doubt, you can try this DIY-Calibration:
- Fill a large polystyrene (e.g.,
Styrofoam) cup (10 oz or larger) (or any Thermos) halfway to the
surface with crushed ice.
- Add cold tap water to ? to 1 inch
below the rim of the cup tip. Two cups, one inside the other,
will provide better insulation and more stable temperatures
throughout the test.
- Immerse the tip of an accurately
calibrated contact probe thermometer, that has been calibrated,
into the water and vigorously stir the water's surface with the
probe for one minute, or until contact probe temperature
stabilizes.
- When the probe temperature has
stabilized, continue stirring the water, while taking
simultaneous temperature measurements with the IR thermometer.
- Hold the IR thermometer within 1
inches of the surface of the water for the most accurate
measurement. Infrared temperature
measurement should be within +/-1˘J (+2°F) of probe reading at
0°C(32°F).
Warning: because such a testing
requires special technique; and for the follow reason, RII has no
guaranty on the result.
Advanced user may use a home made
triple-point (liquid; gas and solid co-exist) to calibrate your
Contact Thermometer,
see Scientific American, January 13, 1999, "Tackling the Triple
Point", By Shawn Carlson
This article provides an innovative way to maintain a temperature
standard about 0.0001 degree C, right in your home and costs less
than $50 to build.
Triple-point of water is a very accurate temperature standard,
much better than "Ice &Water coexist". |
|
|
What else can
I use IRT to measure? |
| |
You can measure the temperature of
almost anything, including the universe! to prove the Big Bang
theory.
In 1965, the remnant radiation from the Big Bang was discovered by
radio astronomers Arno Penzias and Robert Wilson. This radiation,
which peaks at 3 K (-270degC) can be found in all directions in
space.
Such a temperature is an evidence of the Big Bang (the origin of
this universe).
Well , you have to carry an IRT to outer space to get a correct
reading. Well, of course, you need some sophisticated IRT and
maybe a space shuttle to do this measurement.
Our IRT still can't operate in outer space. |
|
|
So this
"Swiss Army Thermometer" can measure anything? |
| |
Yes, it's a Swiss
Army Thermometer. But there are still something impossible to
measure :
Gold, Shining Metal, or any low emissivity material.
For example: the reading of a 125degC gold, is only about 27degC.
For these material with high reflection in IR, what you are
measured is only the REFLECTION.
When IRT fail, try other contact type thermometers
Find..List..Learn About Temperature Sensors at:
www.temperatures.com |
|
|
Hint to get
accurate reading with IRT? |
| |
The target must cover the whole
FOV(Field Of View) of the IRT.
Avoid shining surface(metal), rough surface give better accuracy.
add Electrical Insulating Tape (black is better) on the metal
surface, can solve the problem, give accurate result.
be sure the tape is large enough to cover to Field Of View of the
IRT.
be sure the tape will not BURN. use with caution!
Avoid temperature noise (avoid other High temperature object is
nearby)
for example: you are measuring an IC, with a solder-iron nearby
Try to perpendicular to the target surface. |
|
|
|
|
|
Application
More information above on this page
HACCP INFORMATION
|
Receiving |
 |
|
Refrigerated potentially
hazardous foods:
Frozen foods: 0°F or below
Check temperatures of food upon receipt and reject any potentially
hazardous foods out of accepted ranges
Put perishable foods away promptly.
|
|
 |
Storage |
|
|
Refrigeration(air)
temperature:38°F or below
Refrigeration(food) temperature:41°F or below
Refrigeration-Seafood(food) temperature:30-34°F
Refrigeration-Fresh Produce(food) temperature:
Deep chill:26-32°F
Freezer(food) temperature:0°F or below
Dry Storage:50-70°F
Use open shelving and do not cover with foil
Check foods in multiple locations throughout a cold storage area
,temperature may not be uniform
For ready-to-eat foods prepared on-site,label and comply with storage
time stands(7 days maximum for food held at 41°F or below)
|
|
|
|
Thawing |
|
|
In the refrigerator:41°F or
below
Under running water:70°F or below(water temperature)
Do not thaw at room temperature
If you thaw in a microwave, immediately begin cooking the food after
wards.
|
|
|
|
Cooking |
|
|
Beef roast:145°F or 3 min.
minimum or 140°F for 12min. or 130°F for 121 min.
Beef, steaks, pork, ham, fish, seafood (fillets, chops, or intact
pieces), bacon:145°F for 15 sec., minimum
Ground beef, ground pork, chopped/flaked meals:155°F for 15 sec.
minimum.
Food cooked in microwave:165°F hold 2 min. minimum
Fruits,vegetables:140°F(no minimum time)
Check your local regulations for variations on these standards
For combination dishes, choose the ingredient with the most stringent
standard and follow it
Measure temperature in the thickest part of the food.
|
|
|
|
Cooking - Potentially
Hazardous Food |
|
|
From hot temperature: Cool
to 70°F within 2 hours; and down to 41°F or below with 4more hours(6
hours total).
From room temperature: Cool to 41°F within 4 hours.
Do not cool at room temperature
Use a blast chiller or ice bath to hasten cooling.
Drive food into small units or use a shallow pan.
|
|
|
|
Holding |
|
|
Hot Food:140°F or above
Cold Food:41°F or below
Keep food covered
Stir hot food frequently
Store utensil in food
Take actual food temperature; do not rely on a thermostat setting
Check temperature frequency(at least every 2 hours)
Do not use hot holding equipment to heat or reheat food. |
|
|
|
Reheating |
|
|
Reheat leftovers to a
minimum temperature of 165°F
Food must reach temperature within 2 hours.
|
|
|
|
Potentially Hazardous Foods |
|
|
These foods favor bacterial
growth and require strict temperature control;
Meat, poultry, eggs, seafood, dairy products, cut melon, raw seed
sprout, garlic-in-oil mixture, cooked rice or potatoes, and others
Danger Zone:41 -140
Potentially hazardous foods exposed to this temperature range for a
cumulative total of more than four hours are not safe to eat
More Temperatures
Handwashing water:110
Sanitizing solutions(heat):171 for 30 sec. minimum. |
|
|
