Protective heat shield: device and characteristics

The temperature effect, even with small deviations from the natural regime for a particular environment, can damage some materials. This does not mean that all objects should be adequately protected, but in some technological areas, the availability of such security is very important. For this, a heat shield is used, which forms an insulation in some way. Such means of protection are also used in the professional spheres of construction, and in production, as well as in everyday life.

How is the protective screen arranged?

Typically, such screens are sheets, sheets or panels made from a single material. Another thing is that this material itself is a modified basis, which is obtained as a result of special production procedures. The most common molybdenum and tungsten panels, characterized by high thermal stability. In advanced versions, a thermal screen may have a more complex device. Usually these are two sheets that are separated by a gap with shells - special conical drums. This gap can also have a filling in the form of a thermal protection chip. In some cases, a powder is used from the same molybdenum or tungsten. A structure is formed, according to the principle of operation, resembling plastic windows with a heat-insulating vacuum.

Applications

The scope of use of such screens is very wide. If you do not take into account highly specialized and professional niches, then the most popular will be materials for cars, windows and baths. In the first case, a thermal collector screen is used, which is a simple metal plate. This is a thin sheet, which is usually fixed at four points between the collector and the injector.

In the case of windows, the use of such screens is conditioned by the desire to prevent the penetration of cold into the apartment in the winter. But in such systems, instead of a powder, only air is the filler. A kind of pillow is created, providing an additional barrier in front of the cold. In other words, the thermal shield for installing windows acts as an external insulator, which is effective from the point of view of saving space in the room itself. As for the bath rooms, the screens in them act to isolate specific objects that are sources of high temperatures. In particular, insulators protect boilers and furnaces, preventing dangerous thermal effects on nearby objects.

Basic performance

Manufacturers seek to provide screens with three categories of performance properties. First of all, it is heat resistance. This quality does not simply mean that high temperature waves will not spread beyond the barrier, but also the risk of destructive effect on the material itself, from which the thermal shield and its filler is made, will be eliminated. The second category represents mechanical protective properties, the presence of which ensures that the material will not harm, in addition to heat, physical effects. For example, the same metal is resistant to random shocks and cuts. The third group of properties assumes the presence of other insulating properties. This can be, for example, vapor barrier or noise reduction function.

Characteristics of protective screens

When choosing a screen, one should mainly rely on the ability of the material to provide the above-mentioned heat resistance. The resistance to specific temperatures is the basic characteristic. For example, tungsten panels can withstand a temperature of 3300 ° C, but as this value increases, the melting process begins. In turn, molybdenum cope with its function at a temperature regime of the order of 2610 ° C. But it should be remembered that peak temperatures are not at all a recommendation for use in such conditions. For example, manufacturers recommend using the same tungsten with molybdenum in conditions of 1300-1400 ° C. In addition, the choice takes into account the dimensions that the thermal shield in a particular modification has. In height, they can have 100-150 cm, width - 50 cm, and the depth rarely exceeds 10 cm.

Varieties

Distinguish screens on the design parameters, properties and fields of application. And all three criteria are mutually dependent and determine each other. For example, in the provision of windows for winter time, the most complex functional barrier with a filler made of tungsten can be used, while having the largest size. Specialized heat-resistant panels are used in the arrangement of boilers and furnace facilities. On the other hand, the thermal screen of the exhaust manifold is the simplest solution, which is due to the close conditions of its installation, and relatively modest thermal loads.

Nuances of installation

There are different ways of installation, which are determined by the design of the screen itself and the installation conditions. The most reliable method provides for the initial installation of frames, which are subsequently mounted or fixed by means of brackets or self-tapping screens. It is important to take into account the possibility of future dismantling of the structure. This is especially true for window thermal barriers, which are used only in the winter. Again, the protective thermal shield for the car provides the most affordable way of installation. Typically, manufacturers provide holes in metal sheets and attach kits with hardware to fix the product. Another thing is that the very place of installation near the same collector should match the screen configuration.

Conclusion

In each case, when choosing a heat shield, one should take into account an individual set of qualities. And not always resistance to thermal exposure is decisive. That is, modern materials and modified panels of molybdenum and tungsten, even in budget versions, are able to cope with most heat loads of domestic character. Much more important is the structural correspondence to the installation site. For example, the thermal screen of windows should be designed not only to cover the area of the frames, but also to withstand a certain technological indentation. Even more difficult is the choice, if necessary, of tight insulation of the fireplace or stove. In such cases, often use the services for the manufacture of screens for special orders. This, by the way, applies to protective devices for car collectors.