Usually it’s the weather’s fault when a metal door sticks. If the sun shines, its outer side expands. If it’s cold outside, however, the door bulges inwards. A shear-free insulbar insulating profile from Ensinger (patent pending) minimises this deformation.

Plastics specialist Ensinger has developed a solution for reducing the impact of the bi-temperature effect (also called the bi-metal effect): The new insulating profile consists of two intermeshing parts which, in the event of differing linear expansion between the aluminium shells, move against each other.

“Our new bar has allowed us to create an adaptable insulation zone between the outer and inner shell of a metal door”, explains Matthias Rink, Sales Director for insulbar. “The intermeshing profile sections even out the temperature-related linear expansion. At the same time, the design provides high transverse tensile strength.”

The shear-free insulbar profile can be rolled up and laminated like a conventional insulating bar. It is available in different sizes between 20 and 42 mm. In the insulbar Finder (www.insulbar.com/en/insulbar-finder), with Ensinger’s standard profiles, it is listed under the “Geometry” tab in the “Special applications” section.

Further information on insulbar insulating profiles: www.insulbar.com/

Fig. 1a and b: The shear-free insulbar insulating profile from Ensinger evens out the temperature-related, differing linear expansion of the aluminium shells and simultaneously provides high transverse tensile strength.

Fig. 2: Aluminium assembly with normal insulating profile: The large temperature difference causes the door to become deformed; Fig. 3: Aluminium assembly with shear-free insulbar insulating profile: the flexible insulation zone evens out the differing linear expansion between the inner and outer shells effectively.

Fig. 4: Shear-free insulbar insulating profile: The shear rigidity c is almost zero. Bending of the door is thus significantly minimised.

Picture credits: Ensinger GmbH