How Do Infrared Thermometers Work – Measure Temps Instantly

Last updated on February 3rd, 2023 at 07:14 am

Regarding temperature measurement, infrared thermometers are becoming more and more popular. I wanted to write an article and take a closer look at how do infrared thermometers work. These devices use thermal radiation to measure the temperature of an object without making physical contact, and they can be very accurate when used correctly.

Also called a non-contact thermometer, you must have seen these used in shopping malls, hospitals, and other public places. Let’s discuss how infrared thermometer works and the science behind their operation!

What Is An Infrared Thermometer?

An infrared thermometer, or IR thermometer, is a temperature measurement device that uses infrared radiation to measure an object’s surface temperature. Infrared radiation is a type of electromagnetic radiation, and infrared rays are invisible to the human eye. However, we can feel this type of radiation as heat.

Non-Contact Infrared Thermometer.

Infrared thermometers that use a laser to measure the temperature of an object are called laser thermometers. A laser thermometer is often more accurate than traditional IR thermometers and can be used to measure temperatures from a distance.

Dual laser infrared thermometers have two lasers, one for measuring the temperature of the object and one for measuring the surrounding temperature. This helps provide a more accurate reading, considering the surrounding temperature, which may affect the object’s temperature.

How Do Infrared Thermometers Work?

All objects emit thermal radiation, which increases with the object’s temperature. IR thermometers take advantage of this principle by measuring the amount of thermal radiation emitted by an object and using that information to calculate the object’s surface temperature.

When infrared radiation falls on the object, Infrared thermometers utilize thermal radiation emitted by an object and focus it onto a detector, called a thermopile surface. The sensor then converts this thermal IR radiation into an electrical signal, which is used to calculate the object’s surface temperature.

Distance To Spot Ratio (D:S Ratio)

One of the most important factors affecting an IR thermometer’s accuracy is the distance-to-spot ratio (d:s ratio). The d: s ratio is a measurement of how large an area an IR thermometer can measure at a given distance.

Infrared energy is emitted in a cone shape, and the size of the cone depends on the distance between the IR thermometer and the object. The d:s ratio is the ratio of the diameter of the thermal radiation beam to its distance from the object.

For example, if an IR thermometer has a d:s ratio of 12:01, it can accurately measure a one-inch spot from a maximum distance of 12 inches. The larger the d:s ratio, the more accurate the measured temperature will be.

Thermal Conductivity

Another factor that affects the accuracy of an IR thermometer is thermal conductivity. Thermal conductivity is a measure of how well heat flows through a material.

Some materials, like metals, are excellent conductors of heat, while other materials, like plastics, are poor conductors of heat.

IR thermometers are more accurate when used on materials with high thermal conductivity because those materials allow the IR thermometer to accurately measure the object’s surface temperature.

Emissivity

Emissivity is a measure of how well an object emits thermal radiation. All things have an emissivity value, which ranges from 0 to 1.

Objects with a lower emissivity rating, like metals, emit less thermal radiation than objects with a high emissivity rating, like plastics.

Infrared thermometers are more accurate when used on materials with a high emissivity rating and fixed emissivity rating because those materials emit more thermal radiation. Objects with adjustable emissivity settings give emissivity values far from the exact temperature.

Reflective Surface

Another factor affecting an Infrared thermometer’s accuracy is the object’s surface. A smooth, non-reflective surface is ideal because it allows the IR thermometer to take an accurate reading.

However, many objects have a reflective surface, making taking an accurate reading more difficult. When taking a reading from a reflective surface, it’s essential to use an Infrared thermometer with a laser sight.

The laser sight helps to ensure that the IR thermometer is pointed at the object’s surface rather than its reflection.

Infrared thermometers are a quick and easy way to measure an object’s surface temperature. By understanding how they work and what factors affect their accuracy, you can ensure that you’re taking accurate measurements.

Black Body Radiation

All objects emit thermal radiation, but not all objects emit the same amount of thermal radiation. The amount of thermal radiation an object emits depends on surface temperature.

The hotter an object’s surface, the more thermal radiation it emits. This relationship is known as black body radiation.

Infrared thermometers are most accurate when used on objects with a high surface temperature because those objects emit more thermal radiation.

Working Of Infrared Thermometers – Why Choose Them?

Accuracy

One of the reasons why IR thermometers are so popular is because they’re very accurate. When appropriately used, IR thermometers can accurately be within +/- 0.50°C. Temperature measurements may be 2 degrees less or more than the actual temperature, but with more expensive models, the temperature range of deviation is one degree (less or more).

Reading Speed Or Response Time

IR thermometers are also fast. Most IR thermometers can take temperature readings in less than a second, making them ideal for use when time is of the essence.

Convenience

IR thermometers are also convenient. They’re small and portable, so you can take them wherever you go. You can also use them to measure the temperature of hard-to-reach places, like in the oven or behind a radiator.

Safety

Another reason to choose an IR thermometer is for safety. With an IR thermometer, you can take a temperature reading without coming into contact with the object you’re measuring. This is important when the object’s surface may be hot or contaminated.

Temperature Range

IR thermometers can measure a wide range of temperatures, from -50°C to 3000°C. This makes them ideal for various industries, including food service, healthcare, and manufacturing.

Design

IR thermometers come in a variety of designs, from handheld to fixed-mount. In addition, some IR thermometers come with built-in features, like storage and data logging. With so many options, you’re sure to find an IR thermometer that meets your needs.

Where Is Infrared Radiation Used?

Infrared radiation is a type of electromagnetic radiation. Infrared radiation has a longer wavelength than visible light, making it invisible to the human eye.

Despite being invisible, infrared radiation makes up approximately 50% of the sun’s total output. Therefore, all objects emit infrared radiation, including our bodies.

When we feel the heat from the sun, we feel infrared radiation. We feel infrared radiation when we put our hands on a hot stove.

Infrared radiation is often used for industrial applications, like thermal imaging and night vision. It’s also used in medical applications, like detecting breast cancer and measuring body temperature by focusing on hot spots.

Infrared Thermometer Use

Infrared thermometers are used in various industries, from food service to mechanical equipment and healthcare. They’re also popular among hobbyists and DIYers.

Infrared thermometers are commonly used to measure the temperature of food. However, they’re also used to measure the temperature of industrial processes, like welding and glassmaking.

In healthcare, Infrared thermometers are used to measure body temperature. They’re also used to measure the skin temperature of babies, young children, and patients with fevers.

As you can see, IR thermometers are very versatile and can be used in various industries and applications. So, if you’re looking for an accurate and convenient way to measure temperature, an Infrared thermometer is a great choice.

Tell Me The Best Way To Use An Infrared Thermometer.

• For the best results, aim the Infrared thermometer at the center of the object you’re measuring. Make sure the object is in a well-ventilated area to ensure accurate readings.
• If you’re measuring the temperature of food items, ensure the food is cooked all the way through before taking a reading. For example, raw meat and poultry can give off false internal temperature readings.
• When measuring a person’s temperature, use the forehead mode. This will give you the most accurate reading.
• For objects that are hard to reach, like in the oven or behind a radiator, use the laser sight to help aim the IR thermometer.
• Finally, make sure to clean the Infrared thermometer after each use. This will help ensure accurate readings and extend the life of the device.

Now that you know how to use an Infrared thermometer, you’re ready to start. So, choose a well-ventilated area, aim the IR thermometer at the center of the object you’re measuring, and take a reading of surface temperatures.

How Do Temperature Guns Work?

A temperature gun, also known as an infrared thermometer, measures the temperature of an object without making contact. Infrared thermometers in temperature guns measure the amount of infrared radiation emitted by the object. The most common use for a temperature gun is to measure the temperature of food and the human body. However, it is also used for temperature screening in various settings, such as schools, businesses, and airports.

Conclusion

When taking measurements with an IR thermometer, it’s essential to consider the factors that can affect its accuracy, such as distance-to-spot ratio, thermal conductivity, emissivity, and reflective surfaces. By understanding these factors, you can ensure that you’re taking accurate measurements.

This is important because infrared energy does not come in the visible spectrum of the electromagnetic spectrum, unlike visible light.

The best Infrared thermometers work quickly to measure an object’s surface temperature, but it’s essential to understand how they work and what factors affect their accuracy. Therefore, we recommend taking a few practice measurements to get a feel for your IR thermometer. With some practice, you’ll take accurate temperature readings in no time!

FAQ