DE3940149A1 - Cylindrical hollow body - with heat insulating jacket of microporous material with reduced pressure inside jacket - Google Patents

Abstract

A body is prepd. from a cylindrical hollow body, jacketted with a heat insulation based on a microporous heat insulation material, in which the pressure inside the jacket has been lowered to down to 10power(-6) bars. The microporous heat insulation contains 20-100 (20-89) wt.% of finely divided metal oxide, 0-80 (10-70)% of inert filler, 0-50 (1-50)% of fibrous material, and 0-20 (0-10(% of hardener. The metal oxide is pyrogenic SiO2 and/or Al2O3, opt. treated with a hydrophobising agent. The degree of deformation of the material used for the jacket is 1-100%. The article has several, pref. 1-10, layers. ADVANTAGE - The heat insulation is incombustible, is formed from non-toxic materials, releases no toxic materials on heating, esp. on burning, has low heat conductivity, is impermeable to vapours, and is easily fixed.

Description

The invention relates to a versehe with a thermal insulation NEN, essentially cylindrical hollow body.

Heat insulation body based on pressed, microporous Thermal insulation for cylindrical hollow body are example according to DE-A 36 36 341, DE-A 30 49 871 or the entspre US-A 44 18 724 and DE-A 36 38 579 known. It is Furthermore, from EP-A 03 15 169 and EP-A 01 64 006 or the corresponding US-A 46 36 416 known, thermal insulation molding to provide the type in question with wrappings and to reduce the pressure within the enclosure.

The invention relates to a ver with a thermal insulation, substantially cylindrical hollow body produced from a provided with an envelope thermal insulation molding on the basis of microporous thermal insulation material, wherein the pressure within the enclosure is reduced to 10 ^-6 bar, and a substantially cylindrical hollow body.

Preferably, the hollow body is on its outside with the Thermal insulation provided.

The substantially cylindrical hollow body according to the Er can be used, for example, as a container or housing, in particular as a horizontal, substantially cylindrical  Be formed hollow body. An example of such, horizontal hollow bodies are pipes that also curvatures up can show.

The hollow bodies according to the invention are used for loading promotion or storage, in particular carriage, of cooled or heated, in particular cooled, liquid or gaseous, especially liquid, media.

The insulation contained according to the invention fulfills a Variety of requirements for such thermal insulation such as non-combustibility, non-toxic starting materials, no toxic fission products in the case of influence, especially in fires, low thermal conductivity ability, vapor-proof, and easy transport and easy installation of thermal insulation because of their small space requirement and their high breaking strength. Some of these requirements are already in the state of Technique solved, but these are always neglected tion of other essential requirements had.

As a microporous thermal insulation compressed, finely divided metal oxides are used. The following typical compositions for the thermal insulation material have proven successful:
20-100% by weight of finely divided metal oxide,
0-80 wt.% Inert filler material,
0-50% by weight fiber material,
0-20% by weight hardener.

Preferred compositions contain:
30-89% by weight of finely divided metal oxide,
10-70% by weight of inert filler,
1-50% by weight fiber material,
0-10% by weight hardener.

Particularly good results are achieved with the following compositions:
50-75% by weight of finely divided metal oxide,
20-60 wt.% Inert filler material,
5-20% by weight of fiber material,
0-5 wt .-% hardener.

Examples of finely divided metal oxide are fumed silicas, including arc silicas, precipitated silicas, analogously prepared aluminum oxide, titanium oxide and zirconium oxide, and mixtures thereof and their analogs treated with water repellents. Preference is given to using fumed silica, alumina, their mixture or their analogs treated with water repellents. The finely divided metal oxides have spe cific surfaces of preferably 50-700 m ² / g, in particular 70-400 m ² / g, on.

As inert fillers preferably find metal oxides, Metal carbonates, metal silicates, metal aluminates and / or Metal carbide use. The particle size is preferred way between 0.1 and 200 .mu.m, in particular 0.5 and 40 microns.

Examples of inert fillers are calcium oxide, Cal calcium carbonate, dolomite, ilmenite, titanium dioxide, silicon carbide, Ferrous iron-III mixed oxide, chromium dioxide, zirconium oxide, man gandioxid, iron oxide, silicon dioxide, for example gefäll te silica, alumina, silicon aluminate and zirconium silicate, as well as their mixtures. Preferably, ilminite and calcium oxide used. Be clouding agents as  Fillers used, they have advantageously an absorption maximum in the infrared range between 1.5 and 10 μm.

Examples of fiber material are glass wool, rock wool, Ba Salt wool, slag wool, ceramic fibers, as they are made Melting of aluminum and / or silica won who and asbestos fibers and mixtures thereof. Preferably fibers obtained from the melt of aluminum and / or silica and aluminum silicate.

The fiber length should preferably be between 5 mm and 60 mm move. However, fibers should be used whose fiber length distribution has a maximum over 10 mm has. Preferred fiber lengths are between 20 and 50 mm. The fiber thickness should be 2.5-10 μm for physiological reasons be. Very advantageous fibers have processed let, whose thickness was in the maximum between 2.5 and 6 microns.

Optionally, the microporous, compressed heat insulating materials are provided with inorganic hardener. Such Hardeners are disclosed, for example, in EP-A-29,227 which is expressly referred to in this context. Preferably, borides of aluminum, of titanium, of Zircons, calcium, silicides, such as calcium silicide and Calcium-aluminum silicide, in particular boron carbide turned puts. Examples of other ingredients are basic oxi de, in particular magnesium oxide, calcium oxide or barium oxide. Preferably, 0.1-5.0 wt .-% hardener are used.

The basic body of the thermal insulation used according to the invention molded body based on compressed, microporous thermal insulation fabric can be pressed in addition to these, microporous Insulating materials consist of other insulating materials.  

Here is the arrangement of the different Mate proven materials as a layered body. The layers can by organic or inorganic binders such as water glass of different composition, silica sol or kera mix glue, but also by mechanical fixings like Clamps connected to each other.

Examples of other temperature insulating materials are aluminum minium silicate mats, calcium silicate mats, nonwovens and fabrics from glass wool, rock wool, basalt wool, papers, cardboard and Cellulose, but also metal foils.

Is a laminate of different thermal insulation materials used, so two-layered body are preferred in de NEN one layer according to the invention of compressed microporous Heat insulation material is made and the second layer preferably made of aluminum silicate mats, calcium silicate mats, nonwovens and woven fabrics of glass wool, rock wool or basalt wool stands.

The thermal insulation molding on the basis of pressed, mikropo rous thermal insulation according to the invention provided with a Umhül development, wherein the pressure within the enclosure is reduced to up to 10 ^-6 bar. Since there is always a negative pressure within the envelope, the shells must be naturally gastight and close the body completely. The height of the applied vacuum depends on the required degree of deformation. Preference is given to pressures in the range from 10 ⁰ to 10 ^-3 bar. For the fiction, contemporary thermal insulation moldings only those shells are suitable in which no material separation occurs by thickness decrease during the deformation process. Preferably, casings are used which have a degree of deformation of 1% to 100%, ie are stretchable in length by 1% to 100%. In particular, casings having a deformation degree of from 30% to 60% are used. Preferred materials for the coverings are films based on organic polymers, which may also be thermoplastic, metal foils or combinations thereof in the form of composite films. The thickness of the films depends largely on the erforder union degree of deformation. The following thicknesses of the films have proved to be advantageous:
Films based on organic polymers,
5 to 200 μm, in particular 50 to 70 μm,
Metal foils,
5 to 500 μm, in particular 40 to 50 μm,
Composite films,
7 to 600 microns, especially 50 to 200 microns.

Examples of wrapping material are films based on or ganic polymers of acrylic ester butadiene rubber, acrylic ester-2-chloroethyl vinyl ether copolymers, terpolymers Tetrafluoroethylene, trifluoronitrosomethane and nitrosoper fluorobutyric acid, acylester-acrylonitrile copolymers, Ure Polyester-based rubber, polychlorotrifluoroethyl chloropolyethylene, epichlorohydrin rubber, chloroprene Rubber, chlorosulfonyl polyethylene, epichlorohydrin copoly mers, ethylene-propylene terpolymers, ethylene-propylene-co polymeric, polyethylene-based urethane rubber, vinyli fluoride-hexafluoropropylene copolymers, isobutylene-iso pren rubber, polybutylene, isoprene rubber, methylsili con-rubber with fluorine groups, methyl silicone rubber with Phenyl groups, methyl silicone rubber with phenyl and Vinyl groups, methylsilicone rubber, methylsilicone rubber with vinyl groups, acrylonitrile butadiene rubber, acrylic nitrile-chloroprene rubber, pyridine-butadiene rubber, Styrene-butadiene rubber, styrene-chloroprene rubber, Styrene-isoprene rubber, acrylonitrile-butadiene-styrene-co polymeric, acrylonitrile-methyl methacrylate copolymers, Cellu loseacetat, cellulose acetobutyrate, cellulose acetopropionate,  Cresol formaldehyde, carboxymethyl cellulose, cellulose nitrate, Cellulose propionate, casein, ethylcellulose, epoxide, melamine formaldehyde, polyamide, polycarbonate, polychlorotrifluoroethyl len, polydiallyl phthalate, polyethylene, chlorinated polyethy len, polyethylene terephthalate, phenol formaldehyde, polyisobutene ethylene, polymethyl methacrylate, polyoxymethylene, polyphenylene sulfide, polypropylene, polystyrene, polytetrafluoroethylene, Po lyurethane, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyne Council, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, chlorinated polyvinyl chloride, polyvinylidene chloride, polyvi nylidenfluorid, polyvinyl fluoride, polyvinyl formate, Polyvi nylcarbazole, styrene-acrylonitrile copolymers, styrene-buta diene copolymers, silicones, styrene-α-methylstyrene copoly urea-formaldehyde and unsaturated polyesters, where with these plastics through fibers, such as glass fibers, asbestos fibers, boron fibers, carbon fibers, metal fibers, synthesis fibers or wiskers can be reinforced, or metal foils made of aluminum, copper, iron, iron alloys and alloy conditions of aluminum and magnesium or silicon.

Preferred films based on organic polymers are films based on polyethylene and / or polyamide and / or poly vinyl chloride.

Preferred metal foils are aluminum foils because of their favorable IR reflection behavior.

Preferred composite films have a layer sequence of thermo plastic material / metal foil / thermoplastic material or metal foil / thermoplastic material. Examples sol The composite films have layer sequences of poly amide / aluminum / polyethylene; Polypropylene / aluminum / polypropylene; polypropy len / aluminum / polyamide and polypropylene; Copolymerisate Vinyl chloride and vinyl acetate / aluminum.  

For the preparation of the thermal insulation molding according to the invention First, the basic bodies based on microporous, pressed thermal insulation material according to known methods prefabricated. Preferably, the production includes the following Steps:

• a) pre-compression of the thermal insulation based on fine distributed metal oxide at pressures of 1 to 5 bar, ins special 2 bar or about 2 bar;
• b) pressing the precompressed material into the form of planar plates or simple, symmetrical bodies at final pressures of 8 to 20 bar, the thickness of the re sultierenden forms preferably 1 to 25 mm, esp dere 2 to 10 mm, is;
• c) optionally heating the compressed body at Tem temperatures of 350 to 900 ° C.

When pre-compacting or pressing in the Schüt tion enclosed gases can escape. Therefore, done the compression and compression preferably under application of Negative pressure. Degassing can be done even before compacting or pressing done.

The prefabricated body, which may optionally be provided with layers of further Temperaturisoliermaterialien, wherein their application to the prefabricated body based on pressed, microporous thermal insulation material in a conventional manner by placing, sticking under pressure with adhesives such as silica sol, water glass and ceramic adhesives or mechanical fastening as Klam numbers takes place, is then provided in a conventional manner by placing it with a wrapper. Finally, a negative pressure of up to 10 ^-6 bar, preferably from 10 ⁰ to 10 ^-3 bar, generated within the envelope. This vacuum can be by conventional evacuation with a vacuum pump, wherein finally the enclosure is airtight ver closed, for example, by welding the vorste described composite sheets ago, or by shrinking into suitable, described above, thermoplastic films produced.

For those provided with a thermal insulation, essentially cylindrical hollow body according to the invention are in Ab dependence on the outer diameter of the hollow body preference The following insulation thicknesses are used:

outer diameter insulation thickness 20-200 mm 2-20 mm, especially 2-12 mm 200-500 mm 2-30 mm <500 mm 2-50 mm

Where it is required insulation technology, the Umhül ment provided thermal insulation moldings are multi-layered, preferably configured in 1 to 10 layers, used, wherein the individual layers are arranged offset. A multi-layer insulation arrangement is shown in the figure. Meaning:
1 metallic tube (aluminum),
2 inner flexible heat insulation body,
3 outer flexible heat-insulating body.

Especially with hollow bodies with an outer diameter <400 mm it has proved to be advantageous two to five to choose layered arrangements.

The prefabricated thermal insulation is preferably by Bie formed on the hollow body and by gluing,  and / or by mechanical fixings with the hollow body connected.

In special cases, the entire surface is glued (uneven Surface) but usually a point or line is sufficient Bonding. As adhesive media or adhesion promoter arrive application-related double-sided adhesive tapes, 1- or 2-compo adhesive, as well as the common organic and inorganic adhesive for use.

The mechanical attachment is preferably by means of Double U-bars in the longitudinal direction and / or T-bars in Transverse realized. In addition, the mechanical Stabilized compounds by means of adhesives or adhesive tapes become.

Especially in applications where the body high air are exposed to moisture, as in the reactor me mechanical fasteners, such as holding straps, staples, Fixing wires or metal bands, preferably.

As materials for the substantially cylindrical hollow Body come to those who are also used for such bodies were used. These are in particular Polyvinyl chloride, polyethylene, polypropylene, glasfaserver strengthened plastics and metals, mainly aluminum but also steel, copper or metal alloys.

example 1

An 8 mm thick compressed microporous thermal insulation board of the composition:
53% by weight of fumed silica,
18% by weight of precipitated silica,
20% by weight of calcium oxide,
9% by weight of aluminum silicate fiber,
was provided with a 9 micron aluminum foil which was coated on one side with 75 microns of polypropylene and on the other side with 20 microns polyethylene, and the Umhül development was after within the enclosure, a negative pressure of 10 ^-1 bar was generated, welded in the edge area. This plate of dimensions 480 × 515 mm was placed around a tube (d = 164 mm) and bonded to the joint with a double-sided adhesive tape.

Example 2

The procedure of Example 1 was repeated, however was bordered at the push with a double U-bar.

Example 3

The procedure of Example 1 was repeated with the Modification, that the wrapping consists of a composite foil 20 μm polyethylene and 30 μm polyamide.

Example 4

The procedure according to Example 1 was repeated with the modification that the thermal insulation panel a composition of,
60% by weight pyrogenic silica,
20% by weight of precipitated silica,
10% by weight ilmenite,
10% by weight basalt wool,
had.

Claims (10)

1. Provided with a thermal insulation, substantially cylindrical hollow body produced from a provided with an envelope thermal insulation molding on the basis of microporous thermal insulation material, wherein the pressure within the enclosure is reduced to up to 10 ^-6 bar, and a substantially cylindrical hollow body. 2. Hollow body according to claim 1, characterized gekennzeichet that the microporous thermal insulation material,
20-100% by weight of finely divided metal oxide,
0-80 wt.% Inert filler material,
0-50 wt .-% fiber material and
0- 20 wt .-% hardener contains. 3. Hollow body according to claim 1, characterized gekennzeichet that the microporous thermal insulation material,
20-89% by weight of finely divided metal oxide,
10-70% by weight of inert filler,
1-50 wt .-% fiber material and
0-10 wt .-% hardener contains. 4. Hollow body according to one or more of claims 1 to 3, characterized in that as finely divided metal fumed silica, alumina, their mixture or their be with water repellent traded analogues are used. 5. Hollow body according to one or more of claims 1 to 4, characterized in that as sheaths for the Thermal insulation molding materials with a deformation degrees from 1% to 100%.   6. Hollow body according to one or more of claims 1 to 5, characterized in that the verse verse with Henen thermal insulation molding used in several layers and be arranged offset. 7. Hollow body according to claim 6, characterized in that the coated thermal insulation molding in 1 up to 10 layers are used. 8. Hollow body according to claim 6 or 7, characterized gekennzeich net, that for hollow body with an outer diameter <400 mm at least 2 layers of heat provided with the envelope insulating moldings are used. 9. Hollow body according to one or more of claims 1 to 8, characterized in that the following thicknesses of the heat-insulating body are used depending on the outer diameter of the hollow body: outer diameter insulation thickness 20-200 mm | 2-20 mm 200-500 mm 2-30 mm <500 mm 2-50 mm 10. Use of the hollow body according to one or more of Claims 1 to 9 for transportation or storage of cooled or heated, liquid or gaseous gen media.