GB2279973A

GB2279973A - Fibre glass structures

Info

Publication number: GB2279973A
Application number: GB9414006A
Authority: GB
Inventors: Leo Kaim
Original assignee: KULMBACHER KLIMAGERAETE
Current assignee: KULMBACHER KLIMAGERAETE
Priority date: 1993-07-13
Filing date: 1994-07-12
Publication date: 1995-01-18
Anticipated expiration: 2014-07-12
Also published as: BE1007369A6; GB2279973B; SK81194A3; DE4323359A1; PL304114A1; CZ166594A3; ATA134194A; DE4323359C2; SK281073B6; PL178622B1; GB9414006D0; AT406388B

Description

1 FIBRE GLASS STRUCTURES 2279973 The invention relates to fibre glass

structures, e.g. for at least partially enclosing a thermal insulation member or for making a larger structure for at least partially enclosing a thermal insulation member.

Fibre glass structures for enclosing a thermal insulation member are used principally to enclose the thermal insulation between the heat storage core and the housing of an electrical storage heater. The fibre glass structure may, however, also be used with essentially the same advantages to enclose thermal insulation members on other types of heater, e.g. oil and gas heated boilers. The structure is generally arranged between the casing surrounding the combustion chamber and an outer casing.

Known fibre glass structures for enclosing a heat insulating member, e.g. in the form of a fibre glass sack, comprise normal glass fibres. At temperatures above a threshold temperature (ca. 650OC) the fibres are subjected to a conversion process which leads to embrittlement of the fibre glass after cooling. These known fibre glass structures can disintegrate into pieces after being heated only once to above their conversion temperature. The visual characteristics of the thermal insulation member also suffer severely and the user may conclude that the quality of the material is very poor.

In the conversion process of the fibre glass structure, an undesired change in the thermal and physical properties of the material occurs in addition to the embrittlement. In particular, the known fibre glass 2 to is structures of normal glass substant' ally lose the ability to perf orm their intended function, that is to say to enclose and, in particular, to stabilise the thermal insulation, af ter only a single heating-cooling cycle. It is known that high temperature -resistant glass, for instance quartz glass, is practically insensitive to changes in temperature in the temperature range to which such thermal insulation is typically subjected. Quartz glass is, however, very expensive and mechanically of low load bearing ability.

It is thus the object of the invention to provide a fibre glass structure which may be manufactured economically and which has a relatively high resistance to load, in operational use.

According to the present invention a fibre glass structure comprises at least two mechanically connected glass f ibres of dif f erent materials, of which one is a relatively hightemperature resistant material, e.g. quartz glass, and the other is a less temperature resistant material.

The structure in accordance with the invention may be simply a composite fibre comprising a plurality of glass f ibres which are twisted or plaited together and of which at least one is of high- temperature resistant material. In this case, the composite f ibre may have a central f ibre of high- temperature resistant material which is surrounded by a plurality of fibres of less temperature resistant material. A larger fibre glass structure which may be used for enclosing a heat insulating member may be made from a plurality of such composite fibres by mechanically interconnecting them, e.g. by weaving them 3 into a sleeve or bag shape.

A further embodiment of the invention consists of a woven structure in which the warp fibres are provided in a regular pattern in which warp fibres of high-temperature resistant material are arranged alternately with one or more warp fibres of less temperature resistant material. Alternatively or additionally, the weft fibres may be provided in a regular pattern in which weft fibres of high-temperature resistant material are arranged alternately with one or more weft fibres of less temperature resistant material.

The invention also embraces a heat insulating member at least partially enclosed by a fibre glass structure of the type referred to above.

The present invention also embraces a method of manufacturing a fibre glass structure which comprises mechanically interconnecting a plurality of glass fibres, some of which or a proportion of at least some of which comprise a relatively high- temperature resistant material and the remainder of which comprise less temperature resistant material. The glass fibres may be composite fibres of the type referred to above. Alternatively, the method may include weaving a plurality of glass fibres to form a structure, certain of the warp fibres and/or weft fibres comprising high- temperature resistant material, adjacent pairs of which are spaced apart by one or more fibres of less temperature resistant material.

Thus the fibre glass structure in accordance with the invention still includes glass fibres of conventional type, that is to say of normal glass of relatively high 4 a load bearing ability but relatively low temperature resistance. However, the structure also includes a few fibres of high-temperature resistant material, e.g. quartz glass. These fibres form the temperature resistant "backbone,, of the fibre glass structure. The mechanical connection of the different glass fibres results in the f ibre glass structure maintaining its integrity over a large number of heating cycles and substantially maintaining its visual appearance.

The cost of the fibre glass structure is not substantially greater than that of a structure of conventional glass fibres due to the fact that the predominant proportion of the fibres comprises normal and thus economical glass and only a fraction of them are constituted by expensive glass with high temperature resistant properties. The mechanical load bearing ability of the structure is determined substantially by the properties of the normal glass f ibres. Thus the structure in accordance with the invention combines the advantageous thermal properties of e.g. quartz glass fibres with the superior mechanical properties of normal glass fibres.

Further features and details of the invention will be apparent from the following description of two exemplary embodiments which is given by way of example with reference to the accompanying drawings, in which:

Figure 1A is a schematic side view of a twisted composite fibre with a central quartz glass fibre; Figure 1B is an enlarged sectional view on the line I-I in Figure 1A; Figure 2A is a schematic diagram of a woven fibre glass structure in accordance with the invention; and is Figure 2B is a sectional view on the line II-II in Figure 2A.

The structure illustrated schematically in Figure 1 is a composite thread or f ibre 1 which comprises a central quartz glass thread or fibre 11 and a plurality of outer glass threads or fibres 12 and 13 which extend around it in a spiral configuration. One of the outer glass fibres 12 is made of quartz glass whilst the remaining six 13 comprise normal glass which is very much cheaper than quartz glass.

In alternative exemplary embodiments, which are not illustrated, only one of the fibres of the composite fibre strand need be made from quartz glass or some other high temperature resistant glass like material or one or more quartz glass fibres are twisted or plaited with normal glass fibres in different patterns. For reasons of economy, the use of quartz glass fibres should be minimised.

Such composite threads or fibres may be woven, knitted or mechanically interlocked in any other appropriate manner to form a larger structure, e. g. a sheet, sleeve or bag, which may then be used for at least partially enclosing or sheathing a heat insulating member.

Figure 2 shows an embodiment of a fibre glass structure in accordance with the invention in the form of a fabric 2. Regularly arranged in this fabric are four weft fibres 21 of normal glass alternating with a weft fibre 6 is 22 of quartz glass and four warp f ibres 23 of normal glass alternating with one warp fibre 24 of quartz glass. There are thus relatively thick warp and weft fibres 22 and 24, respectively, between which individual fibres 21 and 23, respectively, of normal glass are arranged. In this case also the principle applies that, in the interest of economy, the use of high temperature resistant glass fibre material, for instance quartz glass fibres, should be limited to that amount which is absolutely necessary to form a structure whose strength or cohesion is sufficient for its intended use.

There are no limitations on structures in accordance with the invention as regards the pattern of the warp and weft threads or the construction of a woven or knitted structure over and above those on conventional glass fibre structures of normal glass.

As is apparent from Figure 2B, the woven structure shown in Figure 2 is a bag-like structure with a front wall and rear wall which, in use, encloses at least one heat insulation member. The woven structure of Figure 2B can also be used as one layer of a multi-layer structure, and there are no limits on the number of the layers.

When the individual fibres 21 and 23 of normal glass break wholly or partially after one or more heating cycles, the temperature -resistant weft and warp fibres 22 and 24 hold the entire woven structure together in the manner of a skeleton and ensure the structural integrity of the structure and thus that the heat insulation member remains enclosed. Without the skeletal fibres 22 and 24 of heat-resistant quartz glass, the entire enclosure would disintegrate and thus come away from the heat A 7 insulation member.

Numerous modifications are possible within the scope of the invention. Thus the inventive principle, namely the use in combination of normal glass and quartz glass threads or f ibres, can also f ind application in other composite glass structures, for instance in single layer wall structures, mats or heat insulating plates, e. g. used as edge protector strips stuck on to cutting edges or the like.

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Claims

1. A fibre glass structure comprising at least two mechanically connected glass fibres of different materials, of which one is a relatively hightemperature resistant material and the other is a less temperature resistant material.

2. A structure as claimed in Claim 1 in which the hightemperature resistant material is quartz glass.

3. A structure as claimed in Claim 1 or Claim 2 consisting of a composite f ibre comprising a plurality of glass fibres which are twisted or plaited together and of which at least one is of high-temperature resistant material.

4. A structure as claimed in any one of Claims 1 to 3 consisting of a composite fibre with a central fibre of high-temperature resistant material which is surrounded by a plurality of f ibres of less temperature resistant material.

A structure comprising a plurality of composite fibres as claimed in Claim 3 or Claim 4 which are mechanically interconnected.

6. A structure as claimed in Claim 1 or Claim 2 consisting of a woven structure in which the warp fibres are provided in a regular pattern in which warp fibres of high-temperature resistant material are arranged alternately with one or more warp fibres of less temperature resistant material.

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7. A structure as claimed in any one of Claims 1, 2 or 6 consisting of a woven structure in a regular pattern in which weft fibres of high- temperature resistant material are arranged alternately with one or more weft fibres of less temperature resistant material.

8. A heat insulating member at least partially enclosed by a f ibre glass structure as claimed in any one of Claims 5 to 7.

9. A method of manufacturing a fibre glass structure which comprises mechanically interconnecting a plurality of glass f ibres, some of which or a proportion of at least some of which comprise a relatively hightemperature resistant material and the remainder of which comprise less temperature resistant material.

10. A method as claimed in Claim 9 in which at least certain of the fibres comprise composite fibres and the method includes making the composite fibres by twisting or plaiting one or more fibres of high- temperature resistant material with one or more fibres of less temperature resistant material.

11. A method as claimed in Claim 9 in which the method of making the composite fibres includes winding a plurality of fibres of less temperature resistant material around a fibre of high- temperature resistant material.

12. A method as claimed in Claim 9 which comprises weaving a plurality of glass fibres into a structure, wherein certain of the warp fibres comprise hightemperature resistant material, adjacent pairs of which A are spaced apart by one or more warp fibres of less temperature resistant material.

13. A method as claimed in Claim 9 or Claim 12 which comprises weaving a plurality of glass fibres into a structure, wherein certain of the weft fibres comprise high- temperature resistant material, adjacent pairs of which are spaced apart by one or more weft fibres of less temperature resistant material.

14. A method as claimed in any one of Claims 9 to 13 in which the hightemperature resistant material comprises quartz glass.

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