Roasting a chicken at 1500oC?

• At what temperature is it more appropriate to open the door of a laboratory furnace?
• Is it possible to exceed the limits set by thermal shock?

Roasting a chicken in a furnace reaching 1500oC is not the best method to check the durability of its parts, although it is quite there...

At Nutec Procal, as manufacturers of insulating parts resistant to high temperatures, we care about the furnaces in which these parts are introduced. Since there is a great thermal difference between the exterior and interior of laboratory furnaces, we wanted to learn what kind of things one could do with this type of equipment. Do you have a furnace? Contact us to find out what we can offer you!

Nabertherm, one of the most renowned manufacturers of laboratory furnaces, states the following in their user manuals:

'Opening the furnace while it is still hot, over 200°C (392°F), can lead to increase wear of the following components: insulation, door seal, heating elements and furnace housing (…)'

Which leads us to the following conclusion: the doors belonging to these systems must be opened at the exact moment we would open our home oven when a chicken is being roasted, and not at a higher temperature.

And why is that? To avoid objects from breaking due to thermal shock, which is caused by a very sudden rise or fall (as in this case) in temperature.

Such a change causes the outer parts of the material to drop in temperature faster than the inner parts. Thus, the surface tends to contract more than the core does, thus restricting free surface contraction. Since the core cannot freely contract, mechanical stresses lead to breaks.

However, at Nutec Procal we have put ourselves to the test and passed with flying colours! We have opened the furnace door while it is at 1,500°C to ensure the durability of our thermal insulation parts. Moreover, we have done so, opening and closing the door 300 times per every half hour, with a test furnace with hinged doors specially designed for the test.

Thanks to this test, we can confirm that besides being highly resistant to temperature, the parts of the new Silform range are also highly resistant to thermal shock.

Would you like to know more about our insulating parts for high-temperature furnaces? Visit our catalogue!