How fumed silica is used in vacuum insulation panels (VIP)
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Brief introduction of vacuum insulation board:
VIP panel is vacuum insulation panel, which is the abbreviation of English Vacuum Insulation Panel. It is a kind of vacuum insulation material. It is composed of filling core material and vacuum protection surface layer. It can effectively avoid heat transfer caused by air convection, and greatly reduce the thermal conductivity, even less than 0.035w/(㎡.k). Due to its environmental protection and high efficiency and energy saving characteristics, it is one of the most advanced and efficient thermal insulation materials in the world. one. In the past, VIP was mainly used in the fields of military industry, shipping incubators and medical incubators. Now VIP has been widely used in refrigerators, freezers, refrigerated trucks, cold storage, refrigerated and refrigerated containers and other fields. In addition, in aerospace, food industry and wall Insulation and other fields have also gradually begun to be used.
01 The main function of the surface diaphragm material is to ensure the vacuum degree in the vacuum insulation panel for a long time. The performance and service life of vacuum insulation panels depend to a large extent on the resistance of the surface membrane material to gas penetration during its use. The lower the degree of vacuum in the vacuum insulation panel, the better its thermal insulation performance. In order to improve the gas permeation resistance of the film, the surface film is a composite film of metal and plastic, such as aluminum foil plastic film.
02 The getter is used to create a vacuum internal environment to maximize the internal vacuum degree and reduce convection and radiation heat transfer.
03 The core material involves the application of silica products, which will be described in detail in the next section.
The role of core material:
As the skeleton material of VIP and a necessary condition for maintaining vacuum, the core material plays a very important role in the VIP system:
01 Panel wall for supporting VIP
02 Control gas conduction and convection heat transfer
03 Infrared shielding and scattering
Core material classification:
Core materials are divided into the following categories according to different materials:
01 Granular core material: fumed silica, silica powder, perlite, etc.
02 Foam core material: foamed polystyrene, foamed polyurethane, etc.
03 Fiber core material: glass fiber, rock wool, ceramic fiber, etc.
Advantages and applications of fumed silica core material:
Compared with other core materials, fumed silica core material has lower thermal conductivity, lower vacuum degree, longer life and low sensitivity to external pressure, which can make VIP board with thinner thickness and lighter weight. Therefore, it is very suitable for making some insulation boxes, refrigerators and insulation materials in buildings. Other relevant materials have outlined the performance and application of VIP, and it is believed that fumed silica core material is most suitable as a building insulation material, and its service life can be maintained for 30 to 50 years. Therefore, fumed silica core material is widely used in buildings in European countries. Keep warm.
Another obvious advantage of fumed silica core material is that silica itself is a very good fireproof material, so buildings or products made of fumed silica VIP board have very high fire resistance. And when fumed silica is used with other types of core materials to make composite core materials, because of its fine particle size and good fusion degree, it can minimize the vacuum degree, quality and thickness of composite core materials.