Why Airis can do what other devices can’t – Multi-wavelength Temperature Analysis

A photo showing Airis components and intricate circuitry in an exploded view

Airis technology works reliably in all situations, thanks to more than a decade of research, development, and real-world use, but we are often asked why Airis is so much better than other stove guards. Well, you are in the right place if you are wondering the same thing! We’re the industry experts in stove guard technology, and there is a good reason why we only supply Airis. Aside from its versatility and robustness, this has a lot to do with its advanced sensor technology that puts it leagues ahead of any other stove guard on the market. Keep reading if you want to find out for yourself!

How most stove guards measure temperature and why they don’t do the job they’re designed to do

A photo of an anologue temperature guage on a yellow embossed paper background

Most stove guards will measure temperature, but the way in which this is done usually falls short of the mark, resulting in either a failure to accurately detect the rising pan heat and are therefore useless in an emergency, or they become a nuisance to the user, constantly disrupting their normal cooking activities. 

These inadequate stove guards rely on a simple but flawed method of temperature measurement that ignores a fundamental issue: pots and pans aren’t all made of the same materials. This means they radiate heat in different ways, even when they are just as hot. Physicists in the room will recognise this common phenomenon. Simple temperature detectors just can’t differentiate between these differences and this can easily throw off the units, tricking them into thinking there is a problem when there isn’t, or more worryingly, that there isn’t a problem when there actually is. That can be a very dangerous situation to be in, relying on a safety device that is inaccurate and has the potential to ignore the hob fires it is designed to prevent. It’s not all bad news though, the wonderful minds at Safera knew this wasn’t good enough for their product, in the same we knew it wasn’t good enough for our customers, so they developed their own stove guard and uniquely patented solution to this problem. This is manifested in the Airis stove guard units. But how did they get around the problem?

The most important consideration for hob safety is to ensure that the temperature of cookware does not rise so high that an oil fire ignites. You would have seen from our blog that different oils ignite at vastly different temperatures. However, the real challenge is to ensure that safe, normal high-temperature frying with the right oil can continue if there’s no danger to the user, allowing them to continue without annoying interruptions from inferior safety devices. 

If cooking is to be safe and unencumbered, the safety device must be able to measure the temperatures of different cookware accurately, taking into account their true temperature and how the heat radiates from each of them.

But, measuring temperature is not as simple as one might think. Often,  pans of different sizes and different materials are used on the hob simultaneously and that would send a basic stove guard into a spin. Identifying a dangerously hot pan amongst them requires more than the single-wavelength type measurement that they rely upon. To do this, you need some pretty clever kit, and that’s where Airis comes in. Let’s find out how.

Traditional single-wavelength and multi-pixel IR sensors cannot distinguish between the thermal radiation of different materials

A picture showing abstract infrared lines representing heat

The difference between the heat radiation of the pans can be one factor of many. If you were to use an off-the-shelf infrared (IR) sensor to measure the temperature of a shiny stainless-steel pan, it might, for example, read 40C, even though the actual temperature of the pan is 100C. This is down to the radiative qualities of the pan materials. If a single wavelength of IR is measured, it is practically impossible to reliably identify the actual temperature of different pans. Airis is the only cooking safety device to overcome this problem, but it’s not as simple as you think.

Some manufacturers attempted to solve the problem by using up to 64- pixel multi-pixel sensors. These can provide information on the temperature differences of the hob surface, but they are not able to accurately measure the differences in the thermal radiation of different materials and so they can’t differentiate between the actual temperatures of the cookware. In fact, by adding pixels, more incorrect measurements can end up being taken! Instead of increasing the number of sensors, the problem needs a different, more sophisticated solution.

Measuring the temperature of the pan is difficult because different materials radiate differently

A picture of different cooking pans lined up

Measuring the temperature directly at the surface of each pan would produce an accurate result, but this is impractical because it’s often obstructed by the food. Infrared measurement is therefore the only practical option for cooker shut-off devices like stove guards.

The challenge of indirect IR measurement is that different materials radiate heat in very different ways as we discussed earlier.

Black cookware, such as cast iron pots or Teflon frying pans, strongly radiate heat. In contrast, shiny pans such as stainless steel emit significantly less heat. This makes accurate measurements across multiple pans at different temperatures far more complicated. But why is the pan temperature so important?

So, why is pan temperature important?

A photo of a person measuring the temperature of a pan over a stove

The infrared ‘seen’ by the sensor comes from the sides and bottoms of the pans. Even where the bottom of a pan is covered in oil, the signature of the infrared emitted still relates to the type of pan underneath. Taking account of the emissivity of the pan surfaces (how they radiate heat) is therefore absolutely essential to obtaining an accurate measurement of the pans’ true temperature. Safera developed an innovative way to do exactly this and it means that the Airis stove guard can operate efficiently and accurately in complex cooking environments that cause so much grief for other devices. So how do they do it?

The sensor system developed by Safera is designed to reliably measure the temperature of all types of cookware

A graphic showing a wave of different colours representing temperature change

There are no ready-made sensors for reliable measurements of the hob surface temperature. Safera has solved the problem by developing its own patented sensor system that measures several different wavelengths of thermal radiation at the same time. At room temperature, most of the wavelengths are in the IR spectrum. By measuring these across different frequency ranges and making use of Planck’s Law (which depends entirely on the temperature of the object being measured and describes the spectrum of blackbody radiation) Airis is able to detect temperatures of all types of cookware, regardless of their material content. 

Thanks to this unique technology, it can assess the speed of the rise in temperature for each pan in use on the hob. It then responds quickly and accurately to dynamic changes and stops any fires before they can start, even when one dangerously overheating pan is among several safer ones. That is seriously clever technology and isn’t available in any other stove guard on the market at present.

The technology in Airis is evident in everyday use

A photo of a disabled elderly man in a wheelchair cooking on a hob protected by Airis stove guard

Because the temperature measurements taken by Airis accurately correspond to a real risk situation, Airis quickly detects hazards and does not alarm unnecessarily during normal cooking – whether you have a Teflon-coated pan, a steel kettle, or both at the same time. This makes Airis the perfect solution for real-life cooking situations at home, especially from those with degenerative or cognitive illnesses who are fighting to hold on to their independence and avoid going into an expensive care home or assisted living facility. Thousands of students have also benefited from Airis installations in their university halls, safe in the knowledge that both they and their flatmates are cooking safely.

A photo of the Airis stove guard sensor unit on a white background

We’ve looked at how most stove guards operate with single wavelength sensors and why this isn’t good enough for the dynamic environments of hob cooking, and why measuring this is so difficult with the different ways pans radiate heat, depending on their material construction. You’ve also found out how Safera developed an ingenious solution to this conundrum, and how that makes Airis the only stove guard that can accurately detect overheating pans and prevent hob fires while avoiding interfering with normal cooking, making the most advanced stove guard and also the least disruptive one available.

If you want to know more about Airis and which solution is best for you, then please visit unicook.co.uk to find out more.

Questions about installing or retrofitting Airis?

You can contact us by phone on 0208 798 3462. We offer an accredited CPD presentation on the BS EN 50615 standard.

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