Tailor-Made Insulation - Wacker Chemie AG

Tailor-Made Insulation

Plant components with complex surfaces such as these flanges are easy to insulate with flexibly adaptable silicone-elastomer mats from ContiTech.

Energy consultancy firm Ecofys extrapolated these heat losses to obtain a value that is representative of German industry as a whole. Ecofys estimates that domestic production sites could save 106 petajoules (or 22 billion kilowatt-hours) of heating energy every year if their operators were to thermally insulate all uninsulated plant components and repair damaged insulation. While these measures would cost around €180 million, they could save the companies €750 million in energy costs every year.

Dr. Jens Storre, who works as a chemist at ContiTech Elastomer-Beschichtungen GmbH in Northeim (Lower Saxony, Germany), explains why fittings and similar built-in parts are often still uninsulated despite such considerable savings potential. “It must be possible to operate these plant components after they’ve been insulated and they must remain accessible for maintenance and repair work. In addition, they usually have such complex designs that thermal insulation with conventional materials is only possible with great effort, if at all.” Dr. Storre is responsible for the research and development of elastomer sheets at ContiTech. He was involved in developing the flexible Conti® Thermo-Protect insulation system.

Silicone Elastomers

Silicone elastomers are rubber-elastic solids derived from polyorganosiloxanes. They are obtained from silicone rubber in a process known as curing (vulcanizing). Here, the polymer chains of the organosilicon macromolecules form a three-dimensional network and the rubber hardens. Silicone elastomers are characterized by a property profile that makes them indispensable in many industrial applications: extraordinary heat resistance, low-temperature flexibility, chemical inertness and biocompatibility. They have a strongly hydrophobic, i.e. water-repellent, surface and do not absorb water; they are very good electrical insulators and poor thermal conductors. A typical characteristic is their high resistance to a large number of physical and chemical influences, which is why, unlike organic rubber compounds, they do not age. Thus, their chemical, physical and technical properties remain virtually constant over the temperature range of roughly -50 to +200 degrees Celsius. Silicone elastomers are also able to withstand continuous exposure to oxygen, ozone and UV radiation.

Effective at Temperatures up to 250 Degrees Celsius

Designed for plant components with difficult geometric shapes, such as flanges, rotary slide valves, branches or gate valves, the system opens up new possibilities for thermal insulation at temperatures of 130 to 250 degrees Celsius. This temperature range is important in the chemical, machine-construction and pulp sectors, as well as in several processes used by the food industry, for example.

The insulation material is a silicone-rubber blend that cures to form a microporous silicone elastomer. The base chosen by ContiTech, which belongs to the Hannover-based Continental group, was a solid silicone rubber from WACKER that cures via a platinum-catalyzed addition reaction. “Their property profile makes silicones ideal for this application,” explains WACKER sales manager Christoph Schlegel. “They are aging-resistant, withstand high temperatures and are poor thermal conductors. The selected silicone rubber yields a silicone elastomer that also has a very high tear and tensile strength.”