CH615977A5 - Apparatus intended for insulating a zone against heat loss - Google Patents

Abstract

The blind comprises a plurality of continuous sheets (22) which are not perforated and practically opaque, held at a distance by spacers (26). Seals are provided at the top and at the bottom and on the sides of the blind so that no convection air currents can be formed. Application to the thermal insulation of the openings of buildings. <IMAGE>

Description

The invention relates to an apparatus according to the preamble of claim 1.

It has become increasingly apparent recently that the currently known sources of energy from the earth are limited and in fact are rapidly depleting. As a result, energy conservation has become a subject of global interest.

Heating and cooling systems in residential, industrial and commercial buildings consume roughly 25% of all energy in some industrialized countries. It is therefore important to note that the transparent single-glazed or double-glazed insulation windows used in these buildings give very poor insulation from heat and therefore represent an important cause of energy consumption. ineffective way. For example, in winter, the heat loss per unit of area through the windows is 3 to 10 times the loss through the adjacent walls, depending on the nature of the wall insulation. Similarly, in summer, the total amount of heat entering through a sunlit window can exceed 10 times that passing through the adjacent wall, as described for example in the publication Ashrae, "Handbook of Fundamentals" (1972), RC Dix and Z. Lavan, "Window Shades and Energy Conservation", Mechanics, Mechanical and Aerospace Engineering Department, Illinois Institute of Technology, 1974. Consequently, significant amounts of energy can be saved when window surfaces are effectively insulated . However, it is desirable that this insulation is obtained without permanent sealing of the windows, and with possible use of these for ventilation as well as for observation of the outside world.

Furthermore, the insulation of other zones in which the permitted thickness is limited can be advantageous.

We have already tried to provide insulation against heat transmission in parts of buildings such as windows, in which only a thin device can be mounted. For example, research done at The Illinois Institute of Technology, by RC Dix and Z. Lavan and published under the title "Window Shades and Energy Conservation", indicates that a single single-leaf window blind is superior to curtains. fabric and venetian blinds to reduce unwanted heat loss from windows. In addition, the insulation effect is better when the blind is fixed on its edges by a tape and has a white or silver reflective surface (p. 23 of the precipitated document).

U.S. Patent No. 2305085 discloses a thermally insulated window blind that can be mounted to the top of a window frame and can be removed, this blind comprising two sheets separated by a spacer under the shape of a wooden rod fixed to the window frame. However, this device has certain drawbacks in practice. The spacer rod tends to wear out the leaves when they are pulled over it, so that they wear out. In addition, no device ensures the cooperation of the blinds and the window frame or prevents the formation of convective air currents in the space between the sheets of the blind when the latter is drawn on the window. . This is an important drawback for the efficiency of the insulating construction described in this patent.

The aforementioned document Ashrae, "Handbook of Fundamentais" (1972) concerns the total emissivity of two surfaces having various average emissive powers and surrounding a single space containing air. However, no mechanical structure is described.

Other blind constructions are described in United States patents Nos. 2140049, 2328257 and 2865446. Each of these constructions is intended to limit the entry of light and air through a window in the manner of a classic blind and is not well suited as an insulating structure preventing heat loss. For example, the blind described in the aforementioned patents Nos. 2140049 and 2328257 includes perforated sheets which facilitate the formation of convection air currents around the sheets and windows on which the sheets are mounted. Similarly, the sheets of the blind of precipitated patent No. 2865446 are formed from an open mesh fabric which does not prevent the formation of convective air currents.

U.S. Patent No. 3,231,006 describes a pneumatically operated rolling closure that includes multiple layers that define inflatable bags containing fluid. However, this device is not intended to constitute insulation and the patent in no way indicates the advantage of using surfaces having low emissivity in multi-layer construction. In particular, the patent in no way cites the limits of emissive power which allow the production of a suitable structure according to the invention.

U.S. Patents Nos. 2247634, 2324423 and 2361762 describe other window closing devices. However, these devices are poor thermal insulators, in the same way as conventional windows.

The apparatus according to the invention, described in detail below, is mounted so that it temporarily or permanently covers a

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surface or area to be insulated and heat is not transmitted. The surface can be that of a wall or an opening such as a window formed in a building. In an advantageous embodiment, used for the insulation of a window, the apparatus constitutes a blind which can be completely closed or opened or placed in any intermediate position and, consequently, it does not prevent normal use. window for the intake of ventilation air or for the entry of light. However, when the blind is pulled at night, during the winter months, the energy saving is significant, since a notable loss of heat is avoided, from the heating device of the building, through the window. Similarly, when this blind is pulled in summer, during the warm months, energy savings are also obtained by limiting the heat intake, thus reducing the cooling usually provided by the air conditioning system of the building. .

In an advantageous embodiment, the apparatus or blind according to the invention is intended to be used with conventional windows, for example sash windows which can slide in a frame. The apparatus comprises several opaque or translucent sheets, that is to say practically non-transparent sheets, which are not perforated and which are fixed to a withdrawal roller mounted so that it covers horizontally the entire width of the window frame. at the upper end. The sheets can be pulled down from the roll so that they cover the window, or they can be brought back on the roll so that the window is uncovered. Obviously, the blind can be mounted so that it can be pulled laterally on the window.

A number of spacers are mounted on one sheet of each pair of adjacent sheets so that the spacers separate the sheets, when they are pulled so that they cover the window, the spacers thus ensuring the delimitation of dead spaces between sheets. These spacers can collapse or overlap so that when the sheets are placed on the roll, they can occupy a small space. In addition, as the spacers are mounted with individual sheets of the blind and move with them during the drawing and removal operations of the blind, the abrasion which can wear the sheets or scratch the surface is minimal. Other embodiments of spacers which do not cause abrasion but which are not mounted on the sheets are also described below.

A surface of low energy emittance is associated with at least one of the sheets and is turned towards the dead space containing air. The energy emittance of the surface is sufficiently low that the total effective emissivity of the surface and the dead space does not exceed 0.60. In particular, the energy emittance of the surface does not exceed 0.60.

Thus, the dead spaces containing air delimited between the adjacent sheets of the blind form an effective thermal insulation, reducing the transmission of heat by conduction and convection. In addition, the low energy emittance surfaces, cooperating with the multiple dead spaces, allow the formation of a device having a low total emissivity and very effectively preventing the transfer of radiation.

The blind according to the invention also has certain practical advantages. In particular, it can be installed as easily as conventional blinds, with the same equipment. As the surfaces of low energy emittance of the device are not worn or scratched by the spacers which move with the sheets or are fixed, the blind has a long duration and allows the effective insulation of a window against the transmission of the heat. As the blind is simple, it can be produced inexpensively, therefore used very widely.

The blind according to the invention can insulate certain building areas such as windows going from floor to ceiling, sliding doors of glass or not and conventional doors. The device can also be used other than in the form of a blind. For example, it can be mounted in an elongated and non-retractable form for insulation of a wall or other part, and it can be mounted so as to be arranged horizontally, vertically or obliquely.

Thus, the invention relates to an apparatus ensuring efficient and practical insulation against the transmission of heat by convection, conduction and radiation, in building zones which only allow the mounting of relatively thin apparatuses.

The characteristics and advantages of the invention will emerge more clearly from the description which follows, given with reference to the appended drawings in which:

fig. 1 is a perspective of the blind according to the invention, when it is pulled inside a conventional window in which it is mounted;

fig. 2 is an elevation of the blind, from the inside with respect to the window in which it is mounted, the blind being in the partially pulled position;

fig. 3 is a vertical section of the blind and the window, along line 3-3 of FIG. 1, in the direction of the arrows;

fig. 4 is an enlarged section relative to FIG. 3, showing an advantageous device for spacing the adjacent sheets which delimit a dead space containing air;

fig. 5 is another enlarged section of the spacers, and it shows how they collapse or overlap when placed on the roller;

fig. 6 is a vertical section of a device enabling the upper part of the blind to be sealed, according to a characteristic different from that of FIG. 3, so that convection currents cannot form between the appliance and the window;

fig. 7 is a vertical section through the plane repeated by the line 7-7 in FIG. 1, downwards, and it represents a device ensuring the sealing on the sides of the blind so that it does not form convection currents;

fig. 8, 9 and 10 are enlarged partial vertical sections similar to FIG. 3 and representing variants of spacing of the adjacent sheets of the blind, with delimitation of a series of dead spaces containing air;

fig. 11 is a vertical section similar to FIG. 3, but shows another embodiment of the spacer, the device being mounted so that it is arranged obliquely;

fig. 12 is a perspective, with parts broken away, showing details of the embodiment of FIG. 11;

fig. 13, 14, 15 and 16 are vertical sections of variant spacers useful in the embodiment of FIGS. 11 and 12;

fig. 17 is a vertical section of a blind according to the invention which can be controlled automatically and / or remotely;

fig. 18 is a perspective view showing the arrangement of a photovoltaic cell intended for controlling the automatic embodiment of FIG. 17, and fig. 19 is a vertical section of another embodiment of the invention, operating automatically.

Figs. 1 and 2 show an apparatus according to the invention in the form of a blind 10 mounted so that it can be pulled in front of a conventional window 12, so that it insulates the window against the transmission of heat by convection , conduction and radiation. However, this blind can also be advantageously used for the insulation of any other opening such as a sliding door, in a commercial, public, industrial or residential building, so that it avoids the transmission of heat. Similarly, it can form a permanent insulation device which is not retractable, suitable for example for a wall. By way of example, it is considered that the window 12 is of the sash type which comprises a frame 14 placed on the sides and at the top and which includes a support 16 which protrudes horizontally outside the bottom part. A closure comprising multiple upper and lower glass panels 18 and 20 is mounted in a well known manner, each of

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panels that can slide in vertical tracks (not shown) so that it goes up or down. In addition, these panels are set back in the chassis 14.

As shown in fig. 3, the blind 10 comprises a number of non-perforated and practically non-transparent sheets 22 which are fixed to a mounted withdrawal roller 24, so that it covers the entire horizontal width of the frame 14, at the upper end. It should be noted that the thickness of the sheets 22 is exaggerated for the sake of clarity. Easily available or slightly modified apparatus can be used for mounting the roller, which may advantageously comprise a conventional spring-loaded withdrawal mechanism (not shown) of the type commonly used for ordinary blinds. This withdrawal mechanism allows the sheets to be moved between a drawing position (fig. 1 and 3) and a recessed position, occupying a small space.

A first sheet of each pair of adjacent sheets 22 of the blind comprises a number of devices 26 for spreading the adjacent sheets in the position which is shown in FIG. 3. In addition, these spacers can be mounted closer to each other at the top of each sheet so that they ensure effective separation of the sheets adjacent to the place where they tangentially leave the roll 24 and therefore have tend to be tight against each other.

In an advantageous embodiment, and as shown in detail in FIG. 4, each spacer 26 is formed of an elongated elastic band in the form of a ribbon which takes a partially cylindrical or curved shape, with an axis parallel to the main axis of the band, and which is fixed for example by sewing or thermal welding , at its upper edge 27, on the surface of the sheet so that the spacers are arranged horizontally or transversely. However, the lower edge 29 of each spacer is free. In addition, each spacer 26 is formed from a material having a large elastic memory, that is to say that the material, when it has been formed to the desired curved configuration, naturally resumes this configuration after deformation. In addition, the devices must undergo thermal fixing so that they do not lose this elastic memory in the heat of summer. Thus, the spacers 26 separate the adjacent sheets over their entire length and ensure the delimitation between the sheets of a dead space 38 containing air. Consequently, this dead space constitutes isolation devices opposing the transmission of heat by conduction and convection.

As shown in fig. 5, the spacers 26 are tightly tightened on the roller 24 when the sheets 22 are removed on the roller, given their shape. More precisely, the radius of curvature of each spacer corresponds to that of the roller 24 at the winding location, and the lower edge 29 of the strips slides only a short distance downwards on the sheet adjacent to that to which it is fixed. The free end 29 is preferably rounded so that the slip, although weak, is also regular. However, as the spacer has a large elastic memory, each spacer tends to keep or take up the radius of the roller 24 when the device is removed from this roller, and to separate the adjacent sheets, unlike the position for removing the sheets on the roller.

As shown in fig. 3, the rear ends 31 of the sheets 22 are fixed to the curved surface of the roller, being circumferentially offset. The spacers are also shifted from one sheet to the next, forming inclined vertical arrangements, so that only a small part of a spacer collapses against another of an adjacent sheet, when the device occupies its position set back. Thus, the distribution of the sheets and spacers is relatively regular when the device is removed from the roller. In this way, although the apparatus may include many sheets, these are kept on the roller 24 in a relatively small space and occupy much less space than an ordinary blind. For example, it is found that an apparatus comprising three sheets, having a length of 2.4 m and a thickness of 38 mm in the pulled position, has a diameter, in the withdrawn position, of 51 mm on a roller having a diameter of 25 mm.

As shown in fig. 3, the outer sheets 22a and 22f are connected to the location 36 because they are formed by the same sheet of material. In addition, each of the separate inner sheets 22b to 22e has an elongated mass 37 at its anterior end so that the sheet elongates well to an actual or approximate point of contact with the continuous sheet 22a-22f at location 36. dead spaces 38 are thus separated from each other at the lower part, by the external sheets 22a and 22f which are in contact with the internal sheets 22b to 22e and which thus prevent the formation of convection air currents. This feature is particularly advantageous, since convection currents could affect the efficient functioning of dead spaces which prevent the transmission of heat by conduction and convection.

When the sheets are removed from the roll, the radii of the outer sheets are greater than those of the sheets closer to the axis of the roll. As a result, the sheet 22f is removed more quickly on the roller 24 than the sheet 22a. However, the construction in the form of continuous sheets allows easy removal without maintenance, despite this phenomenon, because the sheet 22a-22f pivots at location 36. In addition, the ends of the internal sheets 22b to 22e which are ballasted are removed from offset, given the difference in the radii of the sheets on the roll. Suitable discs or large washers can be placed at the ends of the roller 24 so that the sheets are removed evenly.

According to the invention, at least one of the sheets of the blind has a surface 39 of low energy emittance, facing a dead space 38. The energy emittance represents the ratio of the total flux of radiation emitted by a surface to the flux emitted by an ideal black body at the same temperature. In the most advantageous embodiment, at least one side, and preferably both, of each internal sheet 22b to 22e has a surface of low energy emittance and can be formed, for example, by a sheet of copper, nickel , aluminum, silver, gold or an alloy containing these metals. The material sold under the brand Mylar by E.I. DuPont de Nemours & Co., when it has an aluminized coating, is also suitable for the formation of blind sheets having a surface of low energy emittance.

It is found that each surface of low energy emittance must have such an emittance sufficiently low that the total effective emissivity of the surface and the associated dead space does not exceed 0.60. The effective emissivity represents the combined effect of the energetic emittances of the boundary surfaces and the dead space. Consequently, the maximum acceptable energy emittance for a single surface 39 facing a single dead space 38 is 0.60.

In advantageous embodiments of the invention, each surface of low energy emittance has such an emittance sufficiently low that the total effective emissivity of the surface and the associated dead space does not exceed 0.06. Thus, the most advantageous maximum energy emittance for such a single surface 39 facing a single dead space 38 is equal to 0.06. The acceptable value of the energy emittance of the surface can be obtained with any of the aforementioned materials.

The acceptable and advantageous values of the energy emittance and the total effective emissivity, indicated above, must be obtained in the infrared range of the energy spectrum and in the temperature range between - 1 and 55 ° C. The above description therefore indicates that a low energy emittance relates to a surface whose energy emittance does not exceed 0.60.

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Surfaces with low energy emittance combine their properties, with a synergistic effect, with those of an associated dead space containing air and thus provide effective insulation which prevents the transmission of heat by radiation. For example, if U represents the thermal conductance which is the heat flow through a body (usually per unit area), leaving a boundary surface, and arriving at another body, for a temperature difference equal to unity, under calm conditions, and if R represents the thermal resistance, that is to say the inverse of the thermal conductance, R is a measure of the efficiency of a body for the reduction of the transmission of heat. The thermal resistance Rf of each surface or the laminar resistance of a sheet of blind which hangs freely, independently of the energy emittance of the surface, is 0.68. Thus, the total thermal resistance, which is an additive quantity, for the sheet of the blind is Ri = 2Rf = 1.36. The thermal resistance of two sheets with high energy emittance, separated by a dead space, is equal to R2 and is equal to the external laminar resistance of the two sheets 2Rf = 1.36, added to the thermal resistance of the dead space Rasi = 0.96. Consequently, R2 = 2Rf + Rasj = 2.32. Obviously, this value also corresponds to the expected resistance of the configuration of the blind when the sheets have a low energy emittance. However, when the sheets have surfaces of low energy resistance, as indicated above, facing the dead space, the thermal resistance of this space increases and reaches Ras2 = 2.95, so that the total resistance becomes R3 = 2Rf + Ras2 = 4.31. Similar results are obtained by adding other air spaces. Thus, the device according to the invention comprising several blind sheets arranged around several dead spaces each associated with a low energy emittance surface provides effective insulation which reduces the transmission of heat by convection, conduction and radiation.

According to the invention, it is particularly important that the spacers do not deteriorate surfaces with low energy emittance when using a removal mechanism. A non-rotating and fixed spacer in front of which the sheets are pulled can rub the surfaces fixed to a part of the face of the sheet or forming a part of this face, and can disturb its low energy emittance therefore limit the efficiency in cooperation with the dead spaces when insulating against heat transmission. However, spacers of the type described minimize the abrasion of surfaces and therefore preserve the long life of the device according to the invention.

The awning according to the invention also includes features which prevent the formation of convection currents between the device and the window itself. As shown in fig. 3, a flap 40 is fixed to the outer sheet 22a and is ballasted by an elongated rod 42 which is in suitable contact with the upper face of the support 16 when the blind is in the pulled position. Thus, convection air currents cannot form between the lower part of the blind and the support. Similarly, a cantilever comprising two loops 44 which hang is mounted on the underside of the upper horizontal part of the chassis 14. The loops 44 are in sealed contact at the locations 46 so that they delimit dead spaces 47. In addition, each loop has an internal surface 49 with low energy emittance. Consequently, since the loops are intended to be in contact with the external sheet 22f of the blind when the latter is withdrawn on the roller 24, they effectively prevent the formation of convection currents between the frame and the upper part of the device. and also prevent the transmission of heat by conduction and radiation.

As shown in fig. 1 and 7, an elastic joint similar to the valance of FIG. 3 can be formed on the side of the blind. This device 48 mounted on the lateral parts of the chassis 14 comprises two opposite loops 50 fixed in a sealed manner at the locations 51 and formed, for example, of a plastic material having good elastic memory properties and which has a shape allowing close contact with the edges of the blind, thus preventing the formation of convection currents. The loops 50 also surround dead spaces 53 and can have an internal surface 55 of low energy emittance.

As shown in fig. 6, the upper or side seals of FIGS. 3 and 7 can be replaced by the loops shown in fig. 6. This arrangement comprises two loops 54 formed of an elastic material, intended to bear against the blind when the latter is withdrawn on the roller 24, whatever its diameter, during the various stages of withdrawal of the sheet from the store.

Figs. 8 to 10 represent variants of spacers which can be used for the separation of the sheets of the blind as described above. Each spacer is shown in a position corresponding to a withdrawal on a roller which rotates clockwise and not counterclockwise as shown in fig. 3. Fig. 8 shows a spacer integral with the associated sheet and projecting laterally therefrom. More precisely, each sheet 22 comprises, at several vertically distant locations, a first fold 58 formed with a force greater than the elastic limit of the material of the sheet, so that the fold is permanent. This can be, for example, formed counterclockwise. The sheet is then folded clockwise as indicated by the reference 60 on itself, and forms a loop 62. The face of the sheet 22 which is adjacent to the first permanent fold 58 is fixed, for example, by gluing or by heat sealing, with the face in contact at location 64. The sheet is then folded with a second permanent ply 66 again counterclockwise, beyond location 64 for bonding. Thus, part of the sheet protrudes from the edge and forms an arm 68. When a tensile force, for example the weight of the sheet itself as indicated by the arrow F, is applied to the opposite ends of the sheet 22 , the loop 62 tends to turn outwards away from the plane of the sheet, around the fold 58 as indicated by the arrow R. In this way, the loop 62 acts as a lateral spacer between the adjacent sheets and delimits a dead space 38 between them. The dead spaces constitute thermal insulators as described above. The loop 62 is also formed so that it can roll while being tightened on a withdrawal device such as a roller 24. FIG. 9 shows another variant of a spacer which comprises a loop 70 formed by an elongated strip fixed to its upper edge 72 on the sheet 22. The lower end is bent and finally glued on itself at 75. The material of the loop has weak elastic memory properties. Consequently, when the blind is pulled, the loop equalizes the radial forces acting on it and takes an almost cylindrical shape of circular cross section and ensures the separation of the sheets. However, during removal on a roller 24, the loop 70 collapses and allows the sheets of the blind which are very close to be clamped. Fig. 10 shows a third variant of a spacer which comprises a drop-shaped loop 80 formed in an elongated strip formed at its two free edges on the sheet 22 as indicated by the reference 82. The material of the loop 80 also has low elastic memory properties and takes a rounded configuration when the device is pulled so that the radial forces acting on it tend to equalize.

Figs. 11 and 12 show another embodiment of a blind according to the invention which can be used for the insulation of any area which can be isolated by the apparatus of the embodiment of FIG. 3. However, this second embodiment is particularly useful for the isolation of areas such as dormers, greenhouse roofs and other areas arranged obliquely or horizontally. As shown in fig. 11, the blind has several sheets 102 fixed to a roller withdrawal mechanism 104 as described with reference to FIG. 3. The withdrawal mechanism is mounted between two end brackets 106, only one of which is shown in FIG. 11, which are fixed on both sides

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of the area to be isolated, for example on either side of a window or door frame. Several upper spacer rollers 108, which are crazy, are also disposed between the brackets 106 and are mounted so that they are each in contact with only one of the sheets of a pair. Each of the spacer rollers has a non-abrasive surface, for example of soft rubber, which prevents degradation of the low energy emittance surfaces of the sheets described above.

This embodiment can also include an upper valance 110, for example of the type described with reference to FIG. 3, so that the convection air currents cannot pass over the appliance. This upper valance and the side seals described with reference to fig. 3 may also be formed from a magnetic material which conforms closely to the configuration of the blind.

At its free end, the blind has a support 112 in Y having end plates 114 of which only one is shown in FIG. 11. A number of lower idler spacer rollers 116, in a number equal to that of the upper rollers 108,

are mounted between the end plates 114 in the support 112. Each of the lower rollers is remote from the adjacent rollers and may also have a non-abrasive surface, so that the adjacent sheets cannot stick to the rollers.

The outer sheets 102a and 102b are in fact formed by a single continuous sheet which passes over the two outer spacer rollers 116a and 116c. Likewise, the inner sheets 102b and 102c are formed by a single continuous sheet which passes over the lower roller 116b.

The branch 118 of the support 112 in Y, projecting downward, is fixed to a cable or a traction cord 120 passing through a suitable slot 122 of the support 124 of the area to be isolated. The cable 120 passes over a drum 126 which can be driven by a motor 128 via a screw reducer 130 or by a handle or a pulley if necessary, not shown.

It should be noted that the blind can be pulled into its lower position shown in fig. 11 from the recessed position, close to that shown in FIG. 12, by the motor 128 which controls the reduction gear 130, the drum 126 and the cable 120. In addition, it should be noted that the arrangement of the fixed spacers in this second embodiment is particularly useful when the blind is mounted obliquely, for example as shown. This spacer arrangement supports the various sheets 102 of the blind at a certain distance, given the tensile force exerted by the cable drive device. It is also desirable that the withdrawal roller 104 include a robust spring or a motor ensuring the application of a suitable tensile force between the bottom and the top of the apparatus.

As shown in fig. 11, an elastic or magnetic seal 134 can be placed at the upper part of the support 124 so that it abuts against the horizontal branches 136 of the support 112 when the appliance is in the pulled position. These seals prevent the formation of convection drafts under the appliance in the pulled position.

Figs. 13 to 16 show four variants of spacers which are particularly useful in the embodiment of the invention shown in FIGS. 11 and 12, when the adjacent sheets are arranged obliquely or horizontally.

The first embodiment of the spacer shown in FIG. 13 is similar to that described with reference to FIG. 3. However, the spacer 140 shown is in the form of an elongated strip formed of a rigid material which has a curved or partially cylindrical configuration with an axis parallel to the main axis of the strip and which is fixed, by example, by heat sealing, sewing or gluing, over its entire face or at its upper edge 142 to the surface of the sheet, so that it is arranged horizontally or transversely to the sheet. The blind does not include several spacers, but only one for each pair of sheets, in the region for fixing the sheets to the rollers.

As the spacers 140 are rigid, when the apparatus is pulled to its closed position, the sheets are effectively separated, as shown in FIG. 13.

Fig. 14 shows a variant spacer whose principle is similar to that of the embodiment of FIG. 8. This spacer comprises a rigid strip having a curved or partially cylindrical section with an axis parallel to the main axis of the strip. At a first edge 146 of the strip, on one side, the spacer is fixed to the sheet 102b. On the other face and at the opposite edge 148, the spacer is also fixed to the central sheet 102b. Thus, as shown in fig. 14, when this sheet is put under tension, the spacer 144 tends to rotate towards a position in which it is not parallel to the sheet. In other words, the spacer tends to rotate away from the plane of the sheet as indicated by the arrow S. In this way, the spacer constitutes a lateral separation device placed between the adjacent sheets and ensuring the formation dead spaces. When the appliance is removed, the spacer can fold back against the sheets of the blind, which thus occupy little space against the rollers 104.

Fig. 15 shows a fixed spacer comprising a drum 150 concentric with the roller 104 and surrounding the latter. The drum has several slots 152, in the direction of the axis A. Each sheet 102 of the blind is threaded through one of the slots 152. The drum 150 is mounted on the roller 104 so that the slots 152 are arranged transversely in the plane of the sheets pulled when they are in their fully pulled position, as shown in fig. 15, the sheets being kept spaced apart.

Fig. 16 shows another embodiment which is perhaps the least expensive, in the form of an elongated solid member 154 in the form of a foam cam fixed to one of the sheets 102, in the region for fixing the two sheets on the roller 104. This member is arranged transversely to the sheets. This configuration is especially useful when only two sheets are used in the awning and when the price is an important factor.

Figs. 17 to 19 show embodiments of blinds according to the invention with automatic and remote control. In fig. 17, the blind can be moved to its low and high positions by a motor 160 which controls a screw 162 and a pinion 164 which rotates the roller 104 on which the multi-layer blind is mounted. The motor 160 can be controlled automatically by a photovoltaic cell as described in more detail below, or manually by a switch. In addition, the shaft 166 of the motor can be driven by a pulley 168 around which passes a draw cord 170. This variant allows manual control of the blind.

It is desirable that the apparatus be placed between two glazing units of a transparent material 220, for example glass. The glazing minimizes the convection air currents that can form between the parallel sheets. A slight vacuum can be maintained in the space delimited by the glazing so that the convection losses are even more reduced.

Figs. 18 and 19 show a variant of a blind according to the invention, comprising an autonomous motor drive device. This blind comprises a motor assembly placed in the tube 104 of the roller and comprising a flat blade 180 which can cooperate with a conventional mounting support 182 mounted on a window frame 184. The blade 180 has separate parts 186 and 188 between which is disposed a solid insulating shaft 190. Each of the separate parts of the blade 180 is in contact with a suitable elastic contact 192,194 mounted in the support 182. In addition, the parts electrically separated are connected by the shaft 190 to a switch 196 intended to ensure the electrical connection with two brushes 198 and 200. The latter are themselves connected to a motor 202 and a microcomputer 204. The motor has a shaft 206 having a pinion 208 which results in a

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pinion 210, which itself drives a reduction gear mounted in a housing 215. A pinion 212 cooperates with a pinion 214 which is mounted on the fixed shaft 190. Thus, when the motor is running, the blind turns, given its cooperation with the fixed shaft 190. Anti-friction bearings 216 facilitate the free rotation of the blind. 5

The external contacts 192 and 194 are connected to a photovoltaic cell 118 which is mounted on the window 220 in which the apparatus according to the invention is installed, as indicated in FIG. 18. The photovoltaic cell is controlled by incident light from outside. The microcomputer 204 is advantageously programmed so that it causes the blind to be lowered into the pulled position during the hours of the day, when the season corresponds to air conditioning. Similarly, in this same season, the device is moved to its recessed position during the night. During the heating season, the operation is reversed. In particular, the microcalcu615 977

The reader is programmed to control the motor which places the blind in the pulled position at night, during the heating season, and in the withdrawn position during the day during the same season.

It should be noted, from the above description, that the invention is susceptible of numerous variants. It is suitable for many applications, for a particular insulation.

It is found that the use of the blind according to the invention throughout the year allows significant conservation of energy. During winter use, the device prevents significant heat losses from the inside to the outside through an orifice of a building in which it is installed. The device can also be effectively used at night during the winter months. Similarly, in summer, the apparatus according to the invention avoids the introduction into the building of undesirable heat, through the orifices. For example, it can be seen that, in an advantageous embodiment of the invention comprising six blind sheets surrounding five dead spaces, the following results are obtained:

Table I

Results without Results with store store

Single glazed window R 0.96 16.67

U 1.04 0.060

Insulating glass window R 1.54 17.25

U 0.65 0.058 "

These results are obtained when the two faces of each inner sheet have a coating of low energy emittance on the side of the dead space, and when the emissivity E of each spacing is equal to 0.03. It appears that this blind gives an improvement by a factor of 16 compared to a window without a blind, for the reduction of heat transmission, the other parameters having constant values.

It should also be noted that an apparatus according to the invention can be implemented with a number of sheets less than or greater than 6. However, it can be seen that the minimum number of sheets giving acceptable results is 3, that is, the number of spaces is equal to 2. Such a blind gives the following results:

Table II

Results without Results with store store

Single glazed window R 0.96 7.82

U 1.04 0.128

Insulating glass window R 1.54 8.40

U 0.65 0.119

This blind gives an improvement of eight times compared to the. Consequently, the device according to the invention, in its window modes with a single glazing, for the reduction of the transmission of its most advantageous embodiments, very much avoids effective heat by convection, conduction and radiation, when all heat losses and allows a significant conservation of other parameters keep constant values. energy.

R

7 sheets of drawings

Claims (10)

615,977 1. Apparatus intended to isolate an area such as a window, a door or a wall, so that the transmission of heat by conduction, convection and radiation is reduced, said apparatus being characterized in that it comprises several non-transparent sheets and non-perforated blinds, a device intended to separate the sheets of each pair of adjacent sheets so that a dead space is delimited between such adjacent sheets, and a surface associated with at least one of the sheets and facing the dead space, this surface having an energy emittance sufficiently low that the total effective emissivity of the surface and of the dead space does not exceed 0.60. 2. Apparatus according to claim 1, characterized in that the total effective emissivity of said surface and the dead space does not exceed 0.06. 2 3. Apparatus according to claim 1, characterized in that the energy emittance of said surface does not exceed 0.60. 4. Apparatus according to claim 1, characterized in that the energy emittance of said surface does not exceed 0.06. 5. Apparatus according to claim 1, characterized in that the total effective emissivity of the surface and the dead space, not exceeding 0.60, is obtained in the infrared range of the radiation spectrum. 6. Apparatus according to claim 1, characterized in that the total effective emissivity of the surface and the dead space not exceeding 0.60 is obtained in the temperature range between - 1 and + 55 ° C. 7. Apparatus according to claim 1, characterized in that the total effective emissivity of the surface and the dead space not exceeding 0.60 is obtained in the infrared range of the energy spectrum, and in the temperature range between - 1 and + 55 ° C. 8. Apparatus according to claim I, characterized in that the two outer sheets are connected to each other at at least one end, this end ensuring the closure of the dead spaces defined between the adjacent sheets and thus prevent the formation of convection drafts in dead spaces. 9. Apparatus according to claim 8, characterized in that the two outer sheets are formed by a single continuous sheet. 10. Apparatus according to claim 1, characterized in that it further comprises a sealing device preventing the formation of convective air currents between the apparatus and the isolated area.