AU665033B2 - Protection arrangement - Google Patents

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: MICHAEL JOHN PANK Actual Inventor: MICHAEL JOHN PANK Address for Service: COLLISON CO.,117 King William Street, Adelaide, S.A. 5000 Invention Title: PROTECTION ARRANGEMENT Details of Associated Provisional Application: Australian Patent Application No. PK9139 dated 25th October, 1991 The following statement is a full description of this invention, including the best method of performing it known to me: i

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p. p 0 This invention relates to a protection arrangement and in particular to providing thermal protection in respect of window openings in buildings.

There is a well known problem which is how to provide a useful thermal barrier to heat either entering or leaving in respect to the window opening in a building.

The problem is best illustrated by reference to information that in a summer in the southern part of mainland Australia, as much as 12,000 Btu of heat each hour can be admitted through 60 square feet of glass. Such heat will require one extra tonne per hour of airconditioning air.

The problem is especially relevant to multi-storey buildings where it has become a more common practice to provide very large areas of glass windows.

It is known to provide externally located louvres angled in relation to the orientation of the sun so that during a low oientation, the sun will pass between the louvres onto the glass and at a higher orientation, less of the sun 20 will pass between the louvres onto the glass.

The cost of providing such externally mounted essentially rigid louvres of this type is extremely high and there are further problems with such an arrangement. These are, that the louvres themselves will continue to require 25 ongoing maintenance unless they are made of somewhat exotic materials but further, the location of external louvres in an elevated position can effect substantial interference to conventional wind flow to the extent that substantial turbulence can be caused when wind is in the appropriate direction and an appropriate speed and unless the louvres are very firmly affixed, they can 30 rattle.

Other problems with louvres are that there is no winter benefit, window cleaning difficulties exist and there is a protrusion out from the building line.

35 It is of course possible to locate the louvres on the inside of the glass but the problem here is that the glass then acts in the conventional glass house effect '4 way so that the louvres are not effective in blocking heating effect from the sun ,U into the building.

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3 A further technique is to encompass the louvres between two panes of glass one pane being an outside pane and the other being an inside pane.

This certainly avoids the problems of wind access to the Iouvres, but there continues to be an access and maintenance problem such that the mechanical complications of a window having two panes which have to be separable from time to time means that the cost can be considerably higher than might be otherwise warranted.

It is an object of the invention to provide an improved arrangement by which thermal passage in both directions through a window can be better restricted or at least provide the public with a better choice.

The invention can be said to reside in a thermal attenuation arrangement comprising in combination a window with a thermal attenuation screen, the thermal attenuation screen comprising a mesh screen and including means mounting the mesh screen around the periphery of the window to space the mesh screen from the outer surface of the window whereby to effect and maintain an insulating space between the window and the screen It will be seen that what I have discovered is that some forms of plastics S•material mesh screens can by reason of their shape and by reason of the 1individual fibres forming the mesh shapes and the thickness of such fibres can 4 ,,provide the same effect as a louvre so that if such mesh is used with an appropriate fixing technique on the external side of a building window, then significant advantages can be achieved both in terms of heat entering a building through a window opening and as an insulator to prevent heat leaving a building through a window opening.

Further, by reason of the shape of the material and a separation distance from o an external surface of glass, there can be provided a space constrained so as to provide substantial insulating effect both in respect to heat that might otherwise be entering into the building through the mesh and window and in the other case from the window through the mesh.

A feature of the arrangement is that the purpose of the mesh is to attenuate heat transmission and in accord with this purpose it is attached within a C RA selected distance from the external surface of the window of a building.

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The problem of finding an appropriate and effective attachment technique has been a major one.

The significant application for the concept within this specification relates to the location of mesh along the outside of windows of multi-storey buildings where especially on windows in the higher storeys of any building, any externally attached mesh would be subject to the highest of wind speeds, the most substantial direct sun impingement effecting heating and cooling which in turn can create significant softening or expansion or contraction and finally the problem relates to both cost and appearance.

According to a preferred form of this invention there is provided in relation to a mesh attachedwithinthe specified range from the external planar face of a non-openable window, and mesh which has around the perimeter a one of either a hook or loop fastening material, and the other of either the hook or loop fastening material being attached to a surrounding peripheral frame of 1 the window.

By orientating the alignment of the hook material so that it has effective interlocking of the loop material so as to provide best resistance to loosening when being strained by pull into the centre of the attached mesh there is provided an adequate answer to the problem.

I have further found that there is an adhesion material which can be used to affix the loop tape onto an external face parallel to the external planar face of the glass such that such adhered tape can then withstand over a reasonable period of time substantial inundation for instance when it rains, substantial heating when the face is aligned with a maximum sun direction and that this S "can be effected in a manner that is reasonably economic.

It has been found to of significant advantage to provide that both the hook material which in preference is attached to the mesh directly fully around its perimeter and the loop material is attached to equally fully surrounding perimeter location of the window.

According to a further preferred arrangement, the strands forming the mesh screen may be welded together at each crossing point of the horizontal and vertical strands..

The advantage of this arrangement is that under relatively high tensions for holding the screen in position the shape of the whole of the mesh will be held in an alignment so that there will be negligible chance of buckling.

The problem with buckling is that this essentially creates an area of mesh which can be held under somewhat different tension than other parts of the mesh and this firstly provides an appearance which is less than preferred and further, any slackness will allow the area to be more easily worked by the wind and with this occurring, on a constant basis over twenty four hours seven aciays a week, the possibility of damage occurring becomes somewhat higher than would otherwise be the case.

Preferably-the-.window screen is comprised of a mesh-screen of horizontal and vertical strands woven together and each of the strands having a fibreglass strand core and a coating of polyvinyl chloride plastics material.

Such material may be UV resistant and colourfast.

A further preferred feature is that the mesh may be comprised of strands which are black in colour. It is to be emphasised that this of course does not exclude 20 other colours being used where appropriate for the application but the preferred instance is black which provides some advantages from the point of view of being adapted to absorb heat and also light. Another advantage of black strands is that it does not restrict visibility from the inside out while °visibility in is blocked.

There is some advantage in having each of the strands having an external finish which is smooth to the extent of providing a sheen finish, In preference the distance from the vertical planar face of the window of the planar alignment of the mesh lies within the range of 10 mm to 100 mm in distance substantially throughout all of the area encompassed by the mesh.

-A In preference, the mesh material is positioned on the outside of any glass of a window and in so far that its purpose is in relation to heat restriction, it is positioned in respect of a non-openable window.

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-li 6 In preference, the mesh is comprised of materials which cover at least 40% of the area over which the mesh extends and in preference, such covered area is greater than this figure and in one preferred instance is 70% of the covered area leaving thereby 30% open interstices area between the mesh strands. In other words the material of the mesh screen has a mesh and strand size in preference such that when light aligned at right angles to the plane of the screen and directed at the screen more than 40% of such light will be intercepted and less than 70% of such light will be intercepted.

A significant advantage of the arrangement described is that it has been found that visibility can still be adequately achieved provided the interstices are uformed as a relatively small part of the overall area and that the colour of the strands are a dark colour or black.

Further there is advantage where the strands are comprised of a substantially smooth surface so as to provide a substantial reflectance.

I will now describe in greater detail these preferred features that have been found to be of assistance in relation to the invention it being emphasised that none of these described features are necessarily essential to the inventive concept in its broadest form, so each of the details is given by way of illustration only.

The preferred embodiments of the invention provide the following: -Very effective shade coefficients (see Table 1) winter thermal performance increase of glass >High wind shear mounting system (200 KPH) Good outward visibility 30 Inward privacy Frameless -No glass contact o- Will not rattle or rust U.V. stable and colourfast i 35 Design neutral by not protruding from the building line Glare reduction Self extinguishing Anti-theft fittings for ground level installation No recurrent maintenance i rf 7 The system in the preferred embodiment is a durable cost effective maintenance free attenuation screen which will absorb and dissipate up to of the sun's heat and glare before it reaches the glass. The screens can be produced for virtually any commercial window size and shape (including curved windows).

The thermal attenuation arrangement works on an insulating layer effect by controlling the air layer between the outside of the glass and the inside of the fitted attenuation screen. The attenuation screen is mounted in tension on the outside of a given fixed window frame so as to cover in total all exposed glass a minimum of 1/2" (12.5 mm) away from the glass surface. The clearance will be dictated by the outermost window frame so the greater depth (in excess of of the frame, the greater the trans-seasonal performance. All supporting performance figures are for the screen a minimum of 1/2" (12.5 mm) away from glass.

It has been found that the protection arrangement will improve by 15% the thermal performance of 1/4" (6.4 mm) clear glass. The specific density of the attenuation screen does an excellent job in reducing the wind chill factor on the glass surface to maintain warmer more constant temperatures during winter and will improve retention of interior heat.

TABLE 1 25 SOLAR CONTROL PROPERTIES OF PROTECTION ARRANGEMENT Mesh having 17 x 12 strands per inch t I I all, t 1 4 Profile Angle (degrees) sun Solar Optical Properties Ts Rs As Tv O-F Shading Coefficient 1/8" glass 1/4" glass 1/4" HA 26 23 0.32 0.32 0.32 0.32 0.31 0.31 0.26 0.17 0.32 0.32 0.32 0.32 0.31 0.30 0.25 0.17 0.30 0.30 0.30 0.30 0.29 0.28 0.24 0.16 rlctr i r I c

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3la3rsd 8 Symbols Ts Solar Transmittance Rs Solar Reflectance As Solar Absorbance Tv Visible Transmittance HA Heat Absorbing glass Note: attenuators mounted 1/2" from glass 00 900 angle of incidence to attenuator mounted in the vertical position In one preferred embodiment, the screen of the present invention may comprise a heavy duty woven P.V.C. coated mesh (.025" diameter strands) 17 x 12 strands per 25.4 mm heat treated, welded at each crossover point, U.V. stable, colour fast and self extinguishing.

The attenuation screen may in one embodiment use a fixing system which comprises a high density modified hook and loop tough tape. The hook is integrally attached to the attenuator around the total perimeter while the loop is attached to the outermost wall mounted window frame (aluminium or steel framed) using a direct laminated acrylic pressure sensitive adhesive and associated primer.

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Hook Loop 400 hooks per square inch (nylon 66) High density pile nylon 66 napped for maximum engagement Direct laminated acrylic pressure sensitive to back of loop Lord type AP134 930C continuous Adhesive Primer Max Temp Dynamic shear of closure 14 Ibs per square inch. This is somewhat higher than for other applications where dynamic sheer of the mesh and loop closure is about 6 psi.

The closure components are both U.V. stables and light fast black in colour with transparent acrylic P/S adhesive.

Test Results of Attenuation Screen c 1. 9 Basis ASHRAE standard 74 73 method of measuring Solar-Optical Properties of materials.

The solar transmittance solar reflectance solar absorbance (As) for the attenuator alone were determined by direct measurement at profile angles 00 150 300 370 450 600 750 with the attenuation screen mounted 1/2" from glass surface. The values were then used to calculate the shading coefficient (SC) for each attenuation screen at each profile angle when used with 1/8" clear glass, 1/4" clear glass and 1/4" heat absorbing glass. The visible transmittance and the Openness Factor were determined for each of the attenuators at 00 profile angle. The test data and results are presented and stated in percent. (See Table 1) Table 2 shows the effectiveness of the present invention when compared with other methods for attenuators of thermal passage through glass into buildings.

i TABLE 2 EFFECTIVENESS OF PROTECTION ARRANGEMENT COMPARED WITH OTHER WINDOW TREATMENT METHODS WINDOW TREATMENT SHADING INSTANT HEAT COEFFICIENT GAIN Btu H Sq Ft

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Protection arrangement of the 0.30 61 preferred embodiment of this invention with 1/4" clear glass Double glazed cool bronze with 1/4" 0.34 76 clear glass i Double glazed 1/4" heat absorbing 0.54 117 l with 1/4" clear Single glazed 1/4" heat absorbing 0.67 145 Double glazed 1/4" clear both panes 0.80 173 Single glazed 1/4" clear 0.93 201 Single glazed 1/8" clear 1.00 216 ==wm=wn=mwm=6m&=.wmwwfi Note: SHADING COEFFICIENT is the ratio of "solar heat gain" through any given glazing material to the "solar heat gain" under the same conditions if the window were glass.

The above comparison is at 300 angle of incidence.

Further assistance will be gained by reference to a preferred embodiment which shall be described with the assistance of drawings in which: i FIGURE 1 is a plan view in somewhat enlarged form of an mesh screen for one embodiment of the invention, ii FIGURE 2 is a side view of a portion of the mesh screen showing the elements forming the mesh, FIGURE 3 shows the spacing arrangement of the mesh with respect to a glass window pane, 4 20 FIGURE 4 is a front elevation of a window in a building being covered by the mesh screen of the present invention, FIGURE 5 is a side view in cross section of the arrangement as *-shown in Figure 4, SFIGURE 6 is a side view of a security bracket suitable for mounting the mesh screen of the present invention FIGURE 7 is a schematic diagram showing heat flow paths for a window 30 without a screen according to this invention, and FIGURE 8 is a schematic diagram showing heat flow paths for a window with a screen according to this invention.

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4r I 00 4 4 00 0044a 0040 0 0o 4s 11 Referring in detail to the drawings, the mesh 1 is comprised of a plurality of woven threads these including the horizontal threads 2 and the vertical threads 3 each of these having a cross section as is shown typically at Figure 2 which is an elliptical shape and each of which may be comprised of fibreglass central part surrounded by polyvinyl chloride plastics material. The threads may have an average diameter cf 0.1 mm and there may be seventeen such strands per 25.4mm in the vertical direction and twelve strands per 25.4mm in the horizontal.

Each of the strands may be welded together at the crossover point as shown at 16 in Figure 1.

The shape and thickness of each of the strands and their inter-relationship is such that at approximately 700 incidence, through to 900 incidence as shown at 15 in Figure 2, there will be negligible passage of light through the mesh.

If the mesh then is located on a north facing window, and the orientation is as per the arrangement as in Figure 1, then with the sun elevation higher than about 700, obviously this will then provide an effective screen.

Such a mesh may be secured by sewing fully around a perimeter, a tape backed hook material 4 in the manner of "Velcro" hook and loop fastener material with the hooks inwardly facing that is toward the main body of the mesh in each case to provide a maximum holding tension and the 25 corresponding loop material 5 secured to the perimeter frame 6.

It will be particularly noted in Figures 2 and 5 that the mesh 1 is spaced from the window 17 by a distance 18 which may be in the region of from 10 mm to 100 mm. This provides an insulating layer 19. This insulating layer 19 is particularly useful in winter as it prevents loss of heat from a building through a window opening due to a "wind chill factor" of cold winds which cannot impinge directly onto the glass. Similarly gain of heat within a building is prevented in summer due to the insulating layer.

A significant advantage of providing simply a mesh screen with a relatively soft surrounding tape, is that if for any reason at all, the mesh does become dislodged, its falling from a multi-storey building will have no possible detrimental consequences to people located below.

i- I 12 By providing mesh that will be essentially non-distortable, which will have relatively small apertures as compared to the overall area of the mesh, and which has strands which are relatively thick as compared to the apertures, means that there is a substantial louvre effect which provides significant advantages if the mesh is located on a vertical plane and facing a direction subject to the direct rays of the sun.

The discovery is that the advantages are twofold that is there is an effect of limiting access of the suns rays when this is a higher aspect which is likely to be during the hotter parts of the day and during the hotter parts of the season, and secondly by locating the mesh within the stated range from the window pane, it has been discovered that there is provided this insulating layer which provides significant insulation effect.

And all of this is gained without a person inside the building losing access to external viewing which apparently occurs because of the distance the mesh will normally be away from the person viewing the view through the window, and secondly it is significantly assisted by the dark or black colouring of the material defining the mesh. All of these features are achieved with a material that is economic to manufacture, which effects an improvement of the appearance of a building in many cases, and which will not provide significant dangers if dislodged to undcr,ieath passing persons.

In some applications, it is of advantage to ensure that the mesh material cannot be easily removed in the sense that if it is simply a hook and loop type adhesion, then someone can quickly disengage one corner of the mesh and emove the screen simply by pulling.

Accordingly in Figure 6 there is shown a security bracket which comprises a 30 frame 7 in the form of a U-shaped bracket, the peripheral edge of the mesh 8 I being located within the U-shape, a grub screw 9 passing through a wall of the U-shaped bracket 7 to impinge with gripping force on the mesh 8 and jamming this with such pressure against the velcro attachments at 1 0 and 11, the U-shaped bracket being secured by appropriate means such as affixing means 12 to frame 13 of the window area.

Ti-T NT I, -1 'tc 13 Figure 7 shows in a stylised form the heat flow paths for a window without a screen according to this invention. At a latitude of 300 South in mid-summer as much as 230 Btu of heat can fall on each square foot of window glass.

Although 44 Btu are reflected away by the 1/4 inch glass 186 Btu of heat penetrates in through the window.

Figure 8 shows in stylised form the heat flow paths for a window with a screen according to this invention. By the addition of the screen a considerable differe.,ce is achieved. Of the original 230 Btu 28 Btu are reflected away by the screen itself, i38 Btu are adsorbed and dissipated by the screen and only 64 Btu actually reaches the glass. Of this 64 Btu only 52 Btu passes through the glass and into the interior space and 12 Btu are reflected.

It will be seen that by this invention there is provided an arrangement which |i 15 provides considerable advantage over the prior art disclosed.

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Claims (18)

1. A thermal attenuation arrangement comprising in combination a window with a thermal attenuation screen, the thermal attenuation screen comprising a mesh screen and including means mounting the mesh screen around the periphery of the window to space the mesh screen from the outer surface of the window whereby to effect and maintain an insulating space between the window and the screen.

2. A thermal attenuation arrangement as in the preceding claim wherein the material of the mesh screen has a mesh and strand size such that when light aligned at right angles to the plane of the screen and directed at the screen more than 40% of such light will be intercepted.

3. A thermal attenuation arrangement as in the preceding claim wherein less than 70% of such light will be intercepted. A thermal attenuation arrangement as in any one of the preceding claims further characterised in that the window is a non-openable window. A thermal attenuation arrangement as in any one of the preceding claims wherein the mesh screen is spaced from an outer surface of transparent material of the window to have a gap of at least 12.5 mm and not more than 100mm. o o S6. A thermal attenuation arrangement as in any one of the preceding claims wherein the means to mount the mesh screen around the periphery of o othe window comprise releasable fastening means.

7. A thermal attenuation arrangement as in the immediately preceding claim wherein the releasable fastening means comprises a hook and loop type fastening arrangement.

8. A thermal attenuation arrangement as in preceding claim 7 wherein the hook and loop type fastening means comprises a hook material and a loop material which are orientated such that the hook material has effective interlocking into the loop material so as to provide best resistance to Aloosening when being strained by pull into the centre of the attached mesh screen. I-

9. A thermal attenuation arrangement as in any one of the preceding claims wherein the means to mount the mesh screen around the periphery of the window extends fully around the periphery of the screen and the periphery of the window. A thermal attenuation arrangement as in any one of the preceding claims wherein the mesh material is comprised of strands welded together at each crossing point of the strands.

11. A thermal attenuation arrangement as in any one of the preceding claims wherein the mesh is black in colour.

12. A thermal attenuation arrangement as in any one previous claim wherein the mesh screen is comprised of horizontal and vertical strands woven together and wherein each of the strands has a fibreglass strand core and a coating of polyvinyl chloride plastics material.

13. A thermal attenuation arrangement as in preceding claim 7 further 20 characterised in that there is an adhesion material used to affix loop tape providing the loop material onto an external face parallel to external planar face of glass of the window. i

14. A thermal attenuation arrangement as in preceding claim 8 further 25 characterised in that the hook material is attached to the mesh fully around its perimeter and the loop material is attached to the surrounding perimeter location of the window.

15. A thermal attenuation arrangement as in any one of the preceding claims further characterised in that strands forming the mesh screen are welded together at each crossing point of horizontal and vertical strands.

16. A thermal attenuation arrangement as in any one of the preceding claims further characterised in that the mesh screen is positioned on the outside of the outer surface of any glass of a window and in respect of a non- openable window. -I n~ oo a a a o o c~ o oo o a oo D oso D~o r o ool~rr a ooru o~ror~ Do ra e a a o os ~~o c a t 16

17. A thermal attenuation arrangement as in any one of the preceding claims further characterised in that a covered area provided by the mesh screen is within the range of 40 to 70% of the total area of the mesh screen leaving thereby the remainder as open interstices area between strands of the mesh screen.

18. A thermal attenuation arrangement as in any one of the preceding claims further characterised in that dynamic shear of closure between any hook material and loop material is at least 14 Ibs per square inch.

19. A thermal attenuation arrangement as in any one of the preceding claims further characterised in that the shape and thickness of each of the strands of the mesh and their inter-relationship is such that at approximately 700 incidence, through to 900 incidence of light directed at the screen there is negligible passage of light through the mesh.

20. A thermal attenuation arrangement as in any of the preceding claims further characterised in that the window comprises a glazed area forming part of a roof of a building.

21. A method for substantially attenuating transfer of heat through a window of a type having a transparent pane there across, the method including the step of affixing a inesh screen to effect an arrangement in accord with anyone of the preceding claims.

22. A thermal attenuation arrangement substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. o or o Loo l o r* or D o o a r o er r oi, o r r ai r o *a D r*rr o I, o r~ r BI1Q O YsU* U O OIJ 00 O 0 r Dated this 13th day of October 1995. MICHAEL JOHN PANK By his Patent Attorneys COLLISON CO. -4h r i ABSTRACT A window screen comprising a mesh screen and means to mount the mesh screen around the periphery of a window on the outside of the window. The means to mount the mesh screen around the periphery of the window is releasable to enable removal of the screen. The screen is spaced from the outer surface of the window to provide an insulating space between the window and the mesh screen which gives advantages in both summer and winter. The screen is preferably of a fibre glass reinforced plastics mesh. ii i t: I)i :4 f