High-temperature insulation wool

High temperature insulation wool is a man-made material for thermal insulation.

3.1 Classification temperature
3.2 want
3.3 continuous fibers / textile glass fibers (VDI 3469 Part 1)
3.4 Textile yarn

4.1 Erdalkalisilikatwollen
4.2 aluminum silicate wool
4.3 Polycrystalline wools

5.1 Saving of resources

6.1 dusts

History

The melting and heat treatment of metals man used for thousands of the fire. To ensure a safe handling of the fire, (copper, bronze, iron ) and their handicraft workmanship were for the melting of metals early special refractory materials needed, which made the handling of liquid metals or glowing at all possible. Due to the very different conditions of a variety of molded, dense materials ( refractory bricks, fireclay), molded insulating materials ( fire bricks ) and unshaped refractory materials are developed (heavy and light ramming mixes ), each used for specific high temperature applications. For decades, however, also other man-made materials used for thermal insulation, which in the low temperature range are used ( around 200 ° C up to 500 ° C) glass and slag wool.

In the 60's first came in the Federal Republic of Germany " ceramic fibers " on the basis of aluminum silicate on the market and found because of their high temperature resistance and good technical properties (eg, good thermal shock resistance and low thermal conductivity) very fast input in the industrial high temperature insulation. The term " ceramic " fiber is misleading because a number of other materials, and materials are subsumed under this term. For this reason, and because more new materials have been developed for the high temperature range, the nomenclature of the highly refractory fleeces was redefined late 90s. (VDI 3469)

Due to various energy crises ( 70s to present) and the ever- rising price of oil and gas have been, where it was technically possible, more frequently used energy- saving, high- temperature fleeces. Their use in thermal insulation allowed for a lighter construction of industrial furnaces and other technical installations ( heating systems, automobiles) with many economic and environmental benefits. This is particularly noticeable in thinner walls and much smaller masses in the delivery noticeable.

Heavy service: 1500 up to 3500 kg / m³,
Easy delivery: 500 to 1000 kg / m³,
Delivery HTW with: 160 to 300 kg / m³.

High temperature wool ( HTW )

High temperature insulation wool is a synthetically manufactured from mineral raw materials accumulation of fibers with different lengths and diameters. The group of high-temperature wool with a classification temperature > 1000 ° C are amorphous AES and aluminum silicate wools ( ASW ) and polycrystalline wools ( VDI 3469, DIN EN 1094 ). In addition to the distinction based on the chemical composition of man-made fibers, in contrast to natural fibers parallel edges.

Alkaline earth silicate (AES )

The Erdalkalisilikatwollen or English Alkaline earth silicate wool are also known as high-temperature glass wool ( HTGW ). AES Want to consist of amorphous fibers, which are made by melting a combination of CaO, MgO, SiO2 and ZrO2 (see also VDI 3469, Sheet 1 and 5). AES wools are < 900 ° C and generally used at operating temperatures in continuously operating units as well as in the domestic appliance sector.

Aluminum silicate wool ( ASW)

Aluminum silicate wool, also known as ceramic fibers (English Refractory Ceramic Fiber = RCF ) is known, amorphous fibers, which are made by melting a combination of Al2O3 and SiO2, usually in a weight ratio of 50:50 (see also VDI 3469 Part 1 and 5 and Technical Rule 521). Products made of aluminum silicate wool are usually used at operating temperatures > 900 ° C and periodically operating units and critical operating conditions (see Technical Rule 619).

The aluminum silicate wool products are carcinogenic substances in category 2 (according to hazardous materials directive ) " Substances which should be regarded as carcinogenic to humans. " There is sufficient evidence to believe that can generate the human exposure to the substance Cancer. (see literature: " If fibers from catalytic converters / diesel particle released into the environment, which could pose a danger to the community ?")

Polycrystalline wools (PCW )

Polycrystalline wools consist of fibers with an Al2O3 content > 70 wt - %; they are generated in the " sol-gel " process from aqueous dopes. The initially formed water-soluble green fibers ( precursor ) can be crystallized by subsequent heat treatment (see also VDI 3469 sheet 1 and 5). Polycrystalline wools are > 1300 ° C and generally used at operating temperatures of critical chemical and physical conditions of use at lower temperatures.

Definitions

Classification temperature

Classification temperature is defined as the temperature at which, after 24 hours of heat treatment in the electrically -heated laboratory furnace and in inert atmosphere, a linear shrinkage of 4% is not exceeded. Depending on the type of product, the value must not exceed the following limits: 2% for sheets and moldings, 4% for mats and papers. The classification is specified temperature in 50 ° C steps ( starting from 850 and up to 1600 ° C).

Classification temperature does not mean that the product can be used continuously at this temperature. In practice, the continuous use temperature of amorphous HTWs (AES and ASW ) is typically 100 ° C to 150 ° C below the temperature classification. Products from polycrystalline wool can be used generally to classification temperature.

Want

As wool is called an unordered accumulation of fibers with different lengths and diameters. "High temperature will" meet this definition and therefore fall under the term " wool".

Amorphous AES and aluminum silicate wools are produced by the raw materials are melted by means of electric resistance melting process in a furnace. The at the bottom of the tub leaking melt jet is accelerated by blowing method or centrifugal process and drawn into fibers with different Längen-/Durchmesserverhältnissen.

Continuous fibers / textile glass fibers (VDI 3469 sheet 1)

These fibers are produced by means of mechanical drawing process with defined nozzle diameters, while all monofilaments have the technically predetermined desired diameter. When dealing only fibers of a given diameter, but different lengths are released. High temperature insulation wools are, by definition, no fibers, hence the term ceramic is "fibers" incorrect.

Textile yarns

By textile work method, yarns can be produced from wool, which can be processed to diverse products (cords, ropes, towels, clothing). Also, high -temperature insulation wool can be processed textile. It created this high-temperature resistant cords, which are used for example for seals, towels (fire blankets) and heat protective clothing.

Applications

The HTW be assigned due to their working temperature specific applications. These can be moved through special conditions (atmospheric, physical conditions, durability requirements) in individual cases. Each application poses special, very special demands on the refractory material. If these requirements and conditions, which in this case the most suitable product can be selected. Some typical products of HTW are exemplary shown. Usually the HTW products are complemented with traditional refractory products, in order to have a complete solution.

Erdalkalisilikatwollen

The focus of the application of this want is in the range of household appliances (eg thermal insulation of ceramic hobs, microwaves and ovens, but also in the field of automotive engineering (eg positioning mat for diesel particulate filters ) and heating. In industrial applications, the products mostly used in temperature ranges below 1000 ° C, including in the non-ferrous metal industry.

Aluminum silicate wool

Aluminum silicate wool is a product for insulation in industrial fields is substantially at operating temperatures of 800 ° C to 1300 ° C. The focus of their use are wide ranges of industrial furnace, furnace and heating construction, in hot gas filtration, automotive hot- end range of exhaust systems and as a support mats for catalytic converters and diesel particulate filters (DPF).

Polycrystalline wools

The application temperature during the use of products of PCW is mainly over 1,300 ° C. For special applications are found in the industrial sector at temperatures up to 1800 ° C or where chemical resistance is required.

In the ceramic industry (and as china is a part), for example, in industrial furnaces with full - PCW modules worked as insulation and in the field of laboratory furnace technology will form part of PCW for the insulation of the furnace, where, for example denture is made , used.

But even at lower temperature may be useful to an application. This repair intervals of industrial furnaces are then extended by, for example, the ASW - insulation is complemented by expansion joints from PCW, further find combination modules (PCW / ASW) getting more attention in industrial furnaces in the steel industry.

Benefits

Saving of resources

Compared with the classical heat insulating materials such as refractory bricks (calcium silicate and microporous materials), heavy stones ( fire bricks and masses ) and castables can be used as heat insulation materials for many heating processes cause high temperature insulation wools ( HTW ) in energy savings:

In the production and processing of steel and non -ferrous metals.
In the automotive industry, among these, especially in the hot -end range of exhaust systems, as support mats for catalytic converters and diesel particulate filters
In the ceramic industry
In hot gas filtration
But also in the household appliances ( such as thermal insulation of ceramic hobs, microwaves and ovens).

Compared with the classical heat insulating materials, high -temperature insulation wools have a number of economic and environmental benefits. Since each application of HTW products represents an individual solution, a targeted consultation is required. The user must set out the requirements of its thermal process and the HTW distributors can request for this profile, select the appropriate HTW product.

For an up to 50% energy savings compared to conventional stone / concrete deliveries, for example in the field of Stahl-/Nichteisenmetallindustrie possible in Industrieofen-/Feuerungs-/Heizungsbau and in the ceramic industry. This entails an improvement in the efficiency of thermal processes and a reduction in CO2 emissions. Have industrial furnaces and equipment with HTW heat insulation more benefits. Due to lighter steel construction and weigh considerably less than the HTW delivery, lower demands on the foundations, fast assembly / maintenance / repair of the system HTW systems are heat up and cool down faster. This increases the availability and productivity is improved, particularly in batch processes.

Health Hazards

Dusts

The group of dusts include silica dusts that may arise during the loading and processing of man-made inorganic mineral and high temperature insulation wools. The fiber dust with a length about 5 microns, a diameter less than 3 microns and a length to diameter ratio that is greater than 3:1 are considered to be respirable. For high -temperature insulation wool and textile products from this want respirable silica dusts can be released. Accordingly dealing regulations must be observed, which are developed and published by the Federal Ministry of Labour and by representing manufacturers of high temperature insulation wool. Detailed designs are currently in progress and completed.

Hazardous Substances and New Organisms Act 1996 Glass-ceramic#Cooktops

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