New shear-free insulating profile minimises bi-temperature effect in aluminium doors

Windows with aluminium frames play an important part in modern Chinese architecture. Thanks to their many advantages regarding stability, weathering resistance and variety of design, several buildings – predominantly in towns – already incorporate them. Aluminium doors also offer, if properly insulated, a major benefit over high-maintenance wooden doors or plastic doors which cannot be insulated very effectively. They are extremely stable, available in several colours, and very easy to maintain. Until now, however, there has also been one problem with metal doors, because temperature fluctuations may cause them to stick. The German company Ensinger has now developed a solution to this.

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. For this problem the plastics specialist Ensinger has developed a solution for reducing the impact of the bi-temperature effect (also called the bi-metal effect). A shear-free insulbar insulating profile from Ensinger (patent pending) minimises this deformation.

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 Vincent Wei, Sales Director for insulbar in China. “The intermeshing profile sections even out the temperature-related linear expansion. At the same time, the design provides high transverse tensile strength. This means that aluminium doors can now be used in all of China’s climate zones, where it provides a long-lasting and reliable solution.”

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.

Further information on insulbar insulating profiles: or contact us directly under 021-52285111-218.

Ensinger is exhibiting:

Fenestration Bau China
05.11. – 08.11.2019
Shanghai, China

Fig. 1: 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