GB2286797A

GB2286797A - Producing a thermal insulating panel

Info

Publication number: GB2286797A
Application number: GB9403564A
Authority: GB
Inventors: James Anthony Mcloughlin
Original assignee: Micropore International Ltd
Current assignee: Micropore International Ltd
Priority date: 1994-02-24
Filing date: 1994-02-24
Publication date: 1995-08-30
Anticipated expiration: 2014-02-24
Also published as: DE69505284T2; EP0669432A1; GB9403564D0; GB2286797B; DE69505284D1; EP0669432B1; ES2122443T3; ATE172266T1

Abstract

A thermal insulating panel is manufactured from a substantially rectangular sheet (11) of porous material by folding the sheet over on itself to bring a pair of opposite edges (12, 13) into overlying aligned interfacial engagement with one another and securing the overlying edges together along the interface therebetween to form a tubular member having a seam extending in an axial direction. The tubular member is then flattened to form two opposed closed side edges (15, 16) extending in the axial direction and two lateral opposed open side edges (17, 18), the seam being positioned intermediate the two opposed closed side edges. One of the two open side edges (17) is then closed to form an envelope open along one side edge (18) and particulate thermal insulating material is introduced into the envelope through the open side edge which is then closed. Pressure is applied to the exterior of the envelope to consolidate the insulating material and to form a substantially rectangular panel having two opposed side edges (15, 16) neither of which contains the seam. <IMAGE>

Description

2286797 Process for the Production of a Thermal Insulating Panel This

invention relates to a process for the production of a thermal insulating panel comprising an outer porous envelope containing a block of consolidated dry particulate thermal insulating 5 material, particularly, but not exclusively, microporous thermal insulating material.

The term 'microporous' is used herein to identify porous or cellular materials in which the ultimate size of the cells or voids is less than the mean free path of all air molecule at NTP, i.e. of the order of 100 run or smaller. A material which is microporous in this sense will exhibit very low transfer of heat by air conduction (that is collisions between air molecules). Such microporous materials include aerogel, which is a gel in which the liquid phase has been replaced by a gaseous phase in such a way as to avoid the shrinkage which would occur if the grel were dried directly from a liquid. A substantially identical structure can be obtained by controlled precipitation from solution, the temperature and pH being controlled during precipitation to obtain an open lattice precipitate. Other equivalent open lattice structures include pyrogenic (fumed) and electro-thermal types in which a substantial proportion of the particles have an ultimate particle size less than 100 mu. Any of these particulate materials. based for example on silica, alumina or other metal oxides, may be used to prepare a composition which is rr:iicroporous as defiiied above.

The microporous insulating material typically comprises a dry particulate microporous material as defined hereinabove mixed with fibre or filament reinforcement. an opacifier such as titanium dioxide and. for hightemperature use, a small quantity of"alumina powder to resist shrink-age.

It is known to produce such a panel as shown in Figure 1 by taking a substantially rectangular sheet of porous material 1, particularly glass cloth material, and folding it over on itself to bring a pair of opposite edges 2. 3 into overlying aligned interfacial engagement with one another. These overlying edges. and subsequently a further pair of overlying edges 4. 5 adjacent thereto.

-2are secured together by lines of stitching 6, 7 using a suitable sewing machine and appropriate thread or yam. An envelope is thereby formed having an open end 8 through which dry microporous insulating material is introduced into the envelope. After scaling the open end 8, again by stitching, the filled envelope is then placed between opposing plates of a press and pressure is applied to consolidate the insulating material within the envelope, with the accompaniment of displacement of air through the porous sheet material 1 of the envelope. A substantially rectangular rigid thermal insulating panel results.

There can be a disadvantage in a panel produced in this way in that although one side edge 9 of the panel has a smooth contour as a result of the material of the sheet 1 wrapping around it without any join therein, nevertheless the opposite side edge 10 is sornewhat irregular on account of what is effectively a flange of envelope material which protrudes beyond the line of stitches 6.

In application of panels as thermal insulation it is often required to provide a row thereof side by side with the opposite side edges 9 and 10 of one panel tightly abutting corresponding side edges of adjacent panels. Although side edge 9 of one panel can abut a corresponding side edge of another panel with good thermal efficiency. the side edge 10 of the panel may be less efficient in abutting the edge of another panel. Furthermore, the side edge 10 may be aesthetically less satisfactory than the side edge 9.

It is an object of the present invention to overcome or mimmise this disadvantage of the prior art.

The present invention provides a process for the production of a thermal insulating panel comprising the steps of providing a substantially rectangular sheet of porous material. folding the sheet over on itself to bring a pair of opposite edges thereof into over]-,, ing aligned interfacial engagement with one another and securing the overlying edges together along the interface thereberween to form a tube.

W subjecting the resulting tube to a degree of rolling motion on itself and flattening it such that two opposed closed side edges of the flattened tube are formed, neither of which side edges contains the pair of secured overlying edges of the sheet, and such that two opposed open side edges of the tube remain; closing one of the two open side edges of the tube to form an envelope open along one remaining side edge; introducing particulate thermal insulatin-. material into the envelope through the remaining open side edge; closing the remaining open side edge and applying pressure to the exterior of the envelope to consolidate the insulating material, with displacement of air through the porous sheet material, whereby a substantially, rectangular panel is formed having two opposed side edges neither of which contains the said pair of secured overlying edges of the sheet.

The particulate thermal insulating material may comprise microporous thermal insulating material.

is The sheet of porous material preferably, comprises glass cloth material. However it may alternatively comprise other materials such as: paper; cotton; a fibrous s,,-nthetic plastics material. a perforated or porous metal foil; a perforated sheet such as polvethylene, or other plastics material. sheet.

The securing of the overlying edges of the sheet together to form the tube may be effected by 1 e, or by means of a suitable adhes v 1 1 - stapi ng, or. where the material of the sheet permits (e.gglass cloth). bv means of stitching, using an appropriate sewing machine and thread or varil.

The closing of the two opposed side edges of the tube to form the envelope and close the envelope may be effected by. means of a suitable adhesive. or by, stapling. or, where the material of the sheet permits (e. g. glass cloth). by means of stitching, using an appropriate sewing machine and thread or varn.

A stack of panels may be produced, secured together, e.g. by an adhesive, at their major faces.

By means of the process of the present invention, a substantially. rectangular thermal insulating panel is provided having two opposed closed side edges around which the sheet material extends smoothly without any, joins or flanges of the sheet material. A row of such panels is thereby able to be provided for a particular application such that edges of adjacent panels smoothly and efficiently abut one another, and also with improved aesthetic appearance compared with panels prepared by the process of the prior art.

The invention is now described by, -way of example with reference to the accompanying drawings in which Figures 2 to 5 represent perspective views of a thermal insulating panel in consecutive steps of its manufacture according to the process of the invention.

Referring to Figure 2, a substantially rectangular sheet 11 of porous material, in particular of glass cloth material, is folded over on itself to bring a pair of opposite edges 12, 13 thereof into overlying aligned interfacial engagement with one another and these overlying edges 12. 13 are - 9 secured together by means of stitching 14, using a suitable sewing machine and appropriate thread or yarn. Instead of stitching, the edges 12 and 13 could be secured together by means of an adhesive. or by means of staples in a stapling operation.

The resulting tube or loop of material is then subjected to a degree of rolling motion on itself to move the secured edges 12. 13 of the sheet into the position shown in Figure 3 and the tube is then flattened somewhat- In this way, two opposed closed side edges 15. 16 of the flattened tube are formed. neither ofkvhich side edges contains the pair of secured overlying edges 12, 13 of the sheet 11. Two opposed side edges 17. 18 of the tube remain open.

i J 1 In the next stage of the process. as shown in Figure 4, one open edge 17 of the two opposed open side edges 17, 18 is closed by means of a line of stitching 19 (although other means such as an adhesive or staples could be used instead), the secured overlying edges 12, 13) being flattened from their hitherto upstanding position and retained in the flattened position by means of the line of stitching 19. The result is a glass cloth envelope open on one remaining side edge 18.

Particulate microporous thermal insulating material of well known form is then poured into the resulting envelope through the remaining open side edge 18 and this remaining open side edge is closed by stitching, or other means, as for the side edge 17. The envelope containing the insulating material is then located between opposing plates of a press (not shown) and pressure is applied in the direction of arrows 20 to consolidate the insulating material within the envelope.

During consolidation, air from the n-kroporous insulating material is displaced through the porous glass cloth material I I from which the envelope is formed.

The resulting panel of thermal insulating material is rigid and is shown in Figure 5. It is substantially rectangular and is advantageous in that the two opposed side edges 15, 16 are uniform]%. smooth and neither of them contains any joined edges of the glass cloth material. such joined edges 12, 13 being on a major face of the panel and neatly flattened. Tlus is advantageous, aesthetically and also from the aspect of thermal insulation efficiency. If it is 20 required to provide a rosv of such panels in abutting side by side relationship. then since the uniform, smooth side edges 15, 16 of one panel abut similar side edges on an adjacent panel this results in maintenance of good thermal insulation at the interfaces.

If desired. the flanges of glass cloth material protruding beyond the stitching at the edges 17 and 18 of the panel may be finally removed by trimming the panel and the exposed edges of insulation material may, bee coated or treated with a suitable material. A strip of glass cloth material may be secured around these edges by means of an adhesive.

It is to be understood that although the joined edges 12, 13 of the sheet 11 of glass cloth material are shown extending substantially midway across a major face of the panel, this midway position is not essential and any desired position on the major face may be considered.

9 f-

Claims

1. A process for the production of a thermal insulating panel comprising the steps of providing a substantially rectangular sheet of porous material; folding the sheet over on itself to bring a pair of opposite edges thereof into overlying aligned interfacial engagement with one another and securing the overlying edges together along the interface therebetween to form a tube; subjecting the resulting tube to a degree of rolling motion on itself and flattening it such that two opposed closed side edges of the flattened tube are formed, neither of which side edges contains the pair of secured overlying edges of the sheet, and such that two opposed open side edges of the tube remain; closing one of the two open side edges of the tube to form an envelope open along one remaining side edge; introducing particulate thermal insulating material into the envelope through the remaining open side edge; closing the remaining open side edge and applvmcr pressure to the exterior of the envelope to consolidate the insulating material, with displacement of air through the porous sheet material, -vvhereby a substantially rectangular panel is formed having two opposed side edges neither of which contains the said pair of secured overlying edges of the sheet.

2. A process according to claim 1. in which the particulate thermal insulating material comprises microporous thermal insulating material.

A process according to claini 1 or 2, in which the sheet of porous material comprises glass cloth material.

5. A process according to any one of the preceding claims in -which securing of the overlying edges of the sheet together to form the tube is effected by means of an adhesive. or by stapling.

6. A process according to any one of claims 1 to 4 in which securing of the overlying edges of the sheet together to form the tube is effected by means of stitching, the sheet material being selected to be capable of such stitching.

7. A process according to any one of the preceding claims, in which the closing of the two opposed side edges of the tube to form the envelope and to close the envelope is effected by means of an adhesive, or by stapling.

8. A process according to any one of claims 1 to 6, in which the closing of the two opposed side is edges of the tube to form the envelope and to close the envelope is effected by means of stitching. the sheet material being selected to be capable of such stitching.

9. A process for the production of a thermal msulatme panel substantially as hereinbefore reference to Figures -2 to 5 of the accompany ing drawings.

described wi& Y 10. A thermal insulating panel whenever produced by the process of any one of the preceding claims.

0 i Cl Amendments to the claims have been filed as follows 1. A process for the production of a thermal insulating panel comprising the steps of.

providing a substantially rectangular sheet of porous material; folding the sheet over on itself to bring a pair of opposite edges thereof into overlying aligned interfacial engagement with one another and securing the overlying edges together along the interface therebetween to form a tube; subjecting the resulting tube to a degree of rolling motion on itself and flattening it such that two opposed closed side edges of the flattened tube are formed, neither of which side edges contains the pair of secured overlying edges of the sheet, and such that two opposed open side edges of the tube remain; closing one of the two open side edges of the tube to form an envelope open along one remaining side edge; introducing particulate thermal insulating material into the envelope through the remaining open side edge; closing the remaining open side edge and applying pressure to the exterior of the envelope to consolidate the insulating material, with displacement of air through the porous sheet material, whereby a substantially rectangular panel is formed having two opposed side edges neither of which contains the said pair of secured overlying edges of the sheet.

A process according to claim 1, in which the particulate thermal insulating material comprises microporous thermal insulating material.

3. A process according to claim 1 or 2, in which the sheet of porous material comprises glass cloth material.

to

4. A process according to claim 1 or 2, in which the sheet of porous material is selected from: paper; cotton; a fibrous synthetic plastics material, a perforated or porous metal foil; a perforated sheet of polyethylene or other plastics material.

5. A process according to any one of the preceding claims in which securing of the overlying edges of the sheet together to form the tube is effected by means of an adhesive, or by stapling.

6. A process according to any one of claims 1 to 4 in which securing of the overlying edges of 10 the sheet together to form the tube is effected by means of stitching, the sheet material being selected to be capable of such stitching.

7. A process according to any one of the preceding claims, in which the closing of the two opposed side edges of the tube to form the envelope and to close the envelope is effected by 15 means of an adhesive, or by stapling.

8. A process according to any one of claims 1 to 6, inwhich the closing of the two opposed side edges of the tube to form the envelope and to close the envelope is effected by means of stitching. the sheet material being selected to be capable of such stitching.

9. A process for the production of a thermal insulating panel substantially as hereinbefore described with reference to Figures 2 to 5 of the accompanying drawings.

10. A thermal insulating panel whenever produced by the process of any one of the preceding claims.