GB2178765A - Screen mesh - Google Patents

Abstract

A mesh material particularly suited for use as an ultra-violet, visible light and infra-red radiation screen comprises either woven vinyl coated glass fibre yarn or woven aluminium or bronze filaments. The mesh fibres or filaments are woven to form a matrix of substantially rectangular holes, (5) each side of any of the rectangular holes being less than 1.7 mm in length. Preferably the mesh is bonded at the cross over points. The mesh material is of a light colour.

Description

SPECIFICATION Screen Mesh The present invention relates to light-weight but strong mesh material suitable to screen out ultra-violet, infra-red and some visible light radiation. In particular, the present invention relates to a light-weight, resilient, strong mesh material which possesses optimum UV, IR and visible light radiation screening properties when used as a screen for windows or doors on dwellings and other buildings. In addition, the material has advantageous wind reduction and insect screening properties.

Particularly, it is desired to provide a material which maximises UV and IR absorption, such radiation being respectively damaging to interior furniture and creating heat on incident surfaces. Further, it is desirable that the same material allow the transmission of visible light to the greatest degree short of glare.

These are conflicting requirements and a material which provides a suitable compromise is desirable.

The present invention further relates to a screen material as described above which also combines properties of dust reduction and insect screening.

Prior art relating to means for screening out solar radiation and/or insects and/or dust have hitherto taken one of two forms.

The first form is fly screen material, frequently being a mesh of wire, subsequently galvanised and/or painted, and installed in a suitable frame structure to cover window and door openings. Such screens frequently require maintenance by way of painting and also tend to deteriorate with time, the steel wire being prone to rust or to permanent deformation caused for example by household pets and small children pressing against the screen material. Such screens are not particularly suited to solar radiation reduction, the mesh size typically being chosen for ease of manufacture and with a view to maximising the amount of light entering while minimising the possibility of entrance of insects and similar.

The second form of protection relates to film materials which are attached directly to window or door glass. Such materials are chosen for their light reduction properties. Clearly such materials will not aid to keeping insects out. Such tinting materials simply filter light. They cannot prevent radiation from striking the window surface, thus imparting heat to the window surfaces on the dwelling, and thence by convection to the building interior. Further such tinting materials are relatively expensive and time consuming and difficult to install, requiring skill on the part of the installer to ensure that the film is applied in such a way that it appears to be integral with the window pane.It has been known that if such film materials are used, cracking of the window pane may develop due to differential expansion between the film and the glass under either severe heating or severe cooling or severe hot/cool cycling conditions.

None of the above prior art is able to combine the features of solar glare reduction, prevention of heat from reaching the window surface, preventing entry of insects, and providing an optimum balance of light entry with UV and IR radiation reduction.

According to the present invention there is provided a mesh material for use as a window screen, said mesh comprising vinyl coated glass fibre yarn of less than 1/2 mm diameter woven so as to form a matrix of substantially rectangular holes, each side of any of said rectangular holes being less than 1.5 mm in length.

According to a preferred embodiment of the invention there is provided a white mesh material for use as an ultra-violet, infra-red and visible light radiation screen, said mesh comprising vinyl coated glass fibre yarn of 100 Tex woven to a dimension of 32 weft by 18 warp and heat treated to stabilise the mesh.

According to a preferred embodiment of the invention there is provided a light grey mesh material for use as an ultra-violet, infra-red and visible light radiation screen, said mesh comprising vinyl coated glass fibre yarn of 100 Tex woven to a dimension of 32 weft by 18 warp and heat treated to stabilise the mesh.

According to a further preferred embodiment, there is provided a white or light grey coloured mesh material for use as both a UV, IR and invisible light radiation screen and as a wind damping screen, said mesh comprising vinyl coated glass fibre yarn of 100 Tex woven to a dimension of 32 weft by 18 warp and heat treated to stabilise the mesh.

In its preferred embodiment, the mesh of this invention may be arranged to protect a window by mounting the mesh parallel with the window surface and spaced away from it on the outside of the window. In this manner, the invention performs the duty of both an insect screen and a solar radiation damper.

The preferred colouration of the mesh is white or light grey or a shade very similar thereto. It has been found that combination of the preferred lattice spacing and white through to light grey colouring provides optimum performance with respect to desired solar radiation absorption and transmission characteristics.

One embodiment of the present invention will now be described with reference to the drawings: Figure 1 is a perspective view of the preferred embodiment; Figure 2 is a section through one of the strands of yarn; and, Figure 3 is a graphical comparison of shading performance with reference to radiation incidence angle.

Referring to Figure 1, the mesh will be seen to be a woven structure wherein 1 denotes one of the warp fibres and 2 denotes one of the weft fibres.

In Figure 2 the construction of the individual fibres is shown. 3 denotes the glass fibre strands used to provide essential strength to the fibres and 4 denotes the PVC sheath whose combination of composition and colour determines, along with the matrix hole dimension, the radiation absorptive and transmissive properties of the material.

5 in Figure 1 generally denotes one of the rectangular holes appearing between the warp and weft fibre weaving. In one preferred form of construction the yarn is of dimension 100 Tex and woven to form a 32 weft by 18 warp structure. Once woven the structure is subjected to a heat treatment to stabilise the mesh.

Combinations of calculations and extensive experiment have shown that web structures of approximately the dimensions of the preferred construction as immediately before outlined result in the product showing the optimum properties of ultra-violet and infra-red radiation absorption combined with adequate transmission of visible light.

In general, it has been found that white coloured yarn of overall diameter less than or equal to 1/4 mm woven to provide rectangular holes of sides approximately 1.5 mm by 0.5 mm provides the most effective material in terms of optimising the advantages hereinbefore referred.

Light grey material also provides advantages over the black embodiment.

As previously stated, the dimensions of the structure are important for providing the appropriate qualities and combination of strength, durability, radiation absorption and transmission and appearance. In addition, experiments have shown that the optimum colour is white or a colour very similar thereto.

The above referenced dimensioned product coloured white provides an improved solar radiation absorption and transmission characteristic over that of any other colour, the improvement comprising the optimisation of the trade off between preferred maximisation of absorption of ultra-violet and infra-red radiation and preferred maximised transmission of visible light.

Tests have shown the mesh, the subject of the present application, to possess superior characteristics in relation to certain parameters relative to other known mechanical screen materials on the market. The parameters include ability to prevent the passage of small insects, ability to damp the flow of air therethrough, and ability to prevent the passage of visible, IR, and UV radiation radiation consistently over a wide angle of incidence of the radiation.

Tests have shown that the small insect commonly known as the "biting midge" cannot pass through the mesh under test conditions.

The fine mesh material of the present invention not only has a good shading effect and low bug penetration, but also has been shown under test to have a significant breeze velocity reduction capability.

Breeze reduction of the order of 70% has been achieved under test. Such breeze reduction is significantly superior to that of commonly used fly-screen material.

The table below shows test results of solar optical properties of one sample of the mesh material, the subject of the present application.

Solar Optical Properties of Australian Solar Mesh B (Solar Radiation m = 2) Angle of Solar % Absorbance Shading Incidence of Transmit- Reflect- Coeffic Radiation(DEG) tance ance ient 0* 31 4 65 .51 30 29 4 67 .49 45 16 15 69 .35 60 15.5 16.5 68 .34 75 10 21 69 .28 *Measurements at this angle of incidence are total values Figure 3 graphically illustrates the more consistent performance of the applicant's material over a large range of angle of incidence as compared to the performance of more commonly used shade screen material. The tests were carried out with black coloured mesh.The white or light grey coloured mesh of the preferred embodiment of the invention provides improved performance again over what is shown in the graph of Figure 3 The internal construction and method of joining the cross-members provides a strong mesh material which is capable of withstanding significant lateral force. This is a desirable feature when the mesh is to be installed in situations where a strong through-draft is to be expected. The reason is that, in order to prevent high amplitude vibration of the mesh under such conditions, significant tension must be exerted upon the mesh in the installed condition.

The construction of the material therefore allows for a material with neat installed appearance and behaviour and desirable qualities relating to radiation absorption/transmission, wind reduction and insectproofing.

In addition to the advantages already mentioned, use of the invention mounted as a screen exterior to windows or as part of a door additionally provides a structure which does not rust or corrode, is pleasing to the eye, is resilient, provides security through its strength, and helps to minimise entry of dust into living areas. The properties of the material also render it suitable for use in other applications, for example in shielding plants and other vegetation to provide an improved environment for plant growth.

Claims (9)

1. A mesh material for use as a screen, said mesh comprising vinyl coated glass fibre yarn of less than half a millimetre diameter woven so as to form a matrix of substantially rectangular holes, each side of any said rectangular holes being less than 1.7 mm in length, said vinyl coated glass fibre yarn being bonded to adjacent yarns at each point of cross over in the matrix, said mesh material being of a light colour.

2. A white through to light grey mesh material for use as an ultra-violet, infra-red and visible light radiation screen, said mesh comprising vinyl coated glass fibre yarn of 100 Tex, woven to a dimension of 32 weft by 18 warp and heat treated to stabilise the mesh.

3. A metal screen material comprising aluminium or bronze for use as an ultra-violet, infra-red and visible light radiation screen, said mesh being woven to form a matrix of rectangular holes, each side of any of said rectangular holes being less than 1.7 mm in length.

4. The mesh of any preceding Claim wherein the internal dimension of each aperture in said mesh is 1.5 mm i .2 mm by 0.5 mm i .2 mm.

5. The mesh of any one of Claims 1, 2 or 3 wherein the internal dimension of each aperture in said mesh is 1.0 mm i .2 mm by 0.5 mm + .2 mm.

6. The mesh of any preceding Claim wherein said mesh is coloured pure white.

7. A method for the reduction of, in combination, wind, insects and incident radiation comprising mounting the mesh of any preceding Claim in external spaced relation over the whole exterior surface of a window.

8. A white screen mesh material substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

9. A method for the reduction of, in combination, insect and incident radiation comprising placing the mesh as hereinbefore particularly described with reference to Figures 1 and 2 in external spaced relation to the exterior surface of a window or aperture in a dwelling.