THE infrared thermometers are tools fantastic To quickly measure surface temperatures. However, they have their boundaries and know how to use correctly an infrared thermometer is essential. Today we are going to discuss emissivity and manner including this factor key will affect all readings Infrared.
Stay attentive for more than blogs to come on subjects such as the cleaning and storage of infrared thermometers, the choice the infrared thermometer that suits you and calibration of the infrared thermometer.
Now let's go to technical…
Definition of infrared
Energy infrared (Ir) is the part of the spectrum electromagnetic that people meet the most often in daily life. However, a large part passes unnoticed. He is invisible in human eyes, but people can feel it in the form of heat. THE influence infrared is one of three ways whose heat is transferred From one place to another. The other two being the convection and the conduction. Everything around you emits a influence infrared.
The infrared temperature measurement is affected by three main things; emissivity, distance And environment.
Definition of emissivity
Depending on what you point Your infrared thermometer, you will get a variation infrared energy emitted. Emissivity is a measure of the capacity of a material to issue infrared energy. It is measured on a ladder from approximately 0.01 to 1.00. Generally, the more the emissivity index of a material is close to 1.00, the more this material tends to absorb infrared energy thoughtful Or ambient. In short, he only emits his own infrared infrastation.
Emissivity on infrared thermometers
Each object emits, transmits and reflects. THE issue occurs at the time of decide where to measure the temperature, because everything around it will affect Reading. This means that if you don't know emissivity correct object you want to measure, you will not have a temperature precise because the thermometer is set to emissivity incorrect. It also becomes a problem when something is directly in front of the object that you want to measure, like cellophane, cling film or a window.
For example, if you decide to measure the temperature of some sandwiches and that you point your infrared thermometer to packaging, You will get a reading incorrect. The infrared will never measure only the surface temperature. Therefore, you would measure there window in cellophane on the sandwich box.
You can see our emissivity table here:
You can see here the temperature difference on a cup in brushed steel. Indeed, by painting a side of the cup in a painting black mat, This affects the value of emissivity and will therefore give you readings very temperature different.
By simply adjusting emissivity, the temperature will vary, proving that as long as you know what surface you measure and what is emissivity From this surface, you will get a precise reading.
Distance, angle and environment
The angle to which you point your thermometer is a postman very important to make sure you get a reading precise. If you don't face infrared directly, you risk taking readings of the environment. If the object you measure is surrounded by something like stainless steel, the probability that you measure the reflection of the environment is quite high.
There distance is also an element to take into account. Each infrared thermometer has a report distance / target different, which means that he will take a reading from a certain area of the object size to which you aim for. If the thermometer infrared that you use has a large target ratio size (indicated by a lower target ratio number, that is to say lower has 5:1) and that the object is little, You will get a reading inaccurate Because you will capture the environment.
THE infrared thermometers may seem to have many boundaries, But they are really very useful. Infrared thermometers are ideal to take measures surface temperature remotely. They provide relatively precise without ever having to touch the object that you measure. This can be useful when not practical to insert a probe In the element to measure, or if the surface is just out scope And that a surface probe will not work.
Keep an eye on others blogs in the infrared series, to come Soon.
In the meantime, why not take a look at: How to use a laser/infrared thermometer?
