GB2568427A

GB2568427A - Energy-saving solar panel

Info

Publication number: GB2568427A
Application number: GB1903620.1A
Authority: GB
Inventors: Jiang Weiguo
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-08-23
Filing date: 2017-10-19
Publication date: 2019-05-15
Also published as: CN106121131A; WO2018036569A1; US20190211551A1; AU2017317235A1; GB201903620D0

Abstract

An energy-saving solar panel that completely removes the traditional solar panel grid structure. Disposing cylinders of a certain thickness by means such as direct forming or welding at positions of screw holes, and simultaneously disposing frames at the perimeter of different layers of panel material, so as to fix the distances between and relative positions of different layers of panel material. The present method allows the distances between different layers of panel material to be controlled as desired, and the number of layers of the panel material can be increased as desired, thereby achieving desired thermal insulation performance. In addition, the grid structure between the panel material is completely removed, achieving a degree of transparency equivalent to a glass curtain wall.

Description

Energy-saving Hollow Sheet

Field Of Technique [0001] This energy-saving hollow sheet pertains to the construction industry.

Background Techniques [0002] 1) Hollow sheets are multiple-layer panels made of high polymer materials (polycarbonate, polyester resin, polymethyl metharcrylate, polypropylene plastics, etc). Since it was created in the 70s of the 20th century, thanks to its light weight, high strength, and many other properties in terms of thermal insulation, sound insulation, etc., its application has become more and more wide, with an ever-increasing output. Nowadays, its price has fallen to more than 10 CNY per square meter, and more than 20 CNY per kilogram. With such low price, as long as its structure and installation methods can be further improved, then its thermal insulation can be raised to the same level as an insulated brick wall (in the past its thermal insulation was just equal to that of a glass curtain wall), its installation and replacement can be conveniently done, and it can achieve the same full transparency as a glass curtain wall. When the requirements in these three aspects are met, then it can completely substitute curtain walls and roofs during construction of houses, greatly lowering the cost of construction and improving the building's energy-saving to any needed level.

[0003] 2) In the technology of a publicized patent (CN105507432A), a structure of glass curtain wall with any number of layers and cavities is described, which glass can be replaced by other plastic materials produced through directly moulding, welding, etc., bringing any needed thermal insulation performance. The installation of its curtain wall and skylight can be directly carried out inside the room, sparing the traditional scaffold. If the above technology is to be combined with the hollow sheets, as long as the corresponding adjustments and developments are made, the above three requirements can be met. See the details of these adjustments and developments as below.

Technical Solutions [0004] 1) Structure of Energy-saving Hollow Sheet [0005] A) In a traditional hollow sheet, two or more layers of panel are connected one above another with spacing bars in between, which spacing bars form the sectional shape of square, layers of square, beehive, etc. Cavities are formed between the layers of panel, improving the functions of thermal insulation, sound insulation, and boosting its strength. However, up to now the thermal insulation performance of the various hollow sheets can only reach the level of glass curtain wall, not able to rise up to that of thick brick walls, much less that of insulated brick wall. To attain wide application of the hollow sheet at buildings' external wall, this problem of thermal insulation must be solved. Probing into the reasons, it might be noticed that thickness of the grid-shaped spacing bars between the panel of a hollow sheet is around 1 millimeter, which is hundreds times thicker than that of the bubbled plastic's wall, or the insulating cotton's fiber. Thence, during the process of thermal conduction, the heat would not be timely transferred to the air surrounding the hollow sheets' spacing bar like that with the bubbled plastic's wall or the insulating cotton's fiber, forming a thermal bridge with the hollow sheet. If thickness of the hollow sheet's spacing bars is greatly reduced, then it would become too soft to support the multiple layers of panel and keep their relative positions. To solve this problem, the structure in figures 1,2 can be applied: Between panels 1,2,3,4 the spacing bars are totally or mostly cancelled (see the side view in figure 1); At the position of bolt hole 5, cylinders 6,7,8 are set, which cylinders can be produced by directly moulding or welding, etc. and shall have a certain thickness (Surrounding these cylinders insulating rings shall be set); At the four sides of panel 1,2,3,4 shall be set side frame 9 (see the top view in figure 2 and the side view in figure 1); The distances between and relative positions of panels 1,2,3,4 are totally or mainly fixed by cylinders 6,7,8 and side frame 9; During installation, the bolt can pass through cylinders 6,7,8. By this way, the problem of heat conductivity between the multiple panels can be solved, greatly improving its thermal insulating performance. At the same time, the number of the panels' layers can be increased at will, so can the distances between the layers be adjusted (At this time the screws need to be replaced by bolts), so that the renovated hollow sheet can reach any level of thermal insulation. In addition, when all the spacing bars are cancelled, the obstacles to sight would be eliminated at the same time, resulting in the same function of transparency as glass curtain wall.

[0006] B) As the above energy-saving hollow sheet has cancelled the spacing bars between the panels, its strength would be decreased to an extent. At places where it needs to be stronger, thickness of its outer layers of panel can be increased; If its function of transparency does not need to be kept, the structure in figure 3 can also be applied: Hollow sheet l's cavities 2,3 keep the traditional spacing bars; Cavities 4,5,6 apply the insulating structure described above; At the two sides 7,8 of cavities 4,5,6 the spacing bars are also kept. Depending on the specific requirements on strength and insulation, the number of structural cavities 2,3 etc. and that of the insulating cavities 4,5,6 etc. can be adjusted accordingly. If the width of cavities 4,5,6 is not great, cylinder 9 can be canceled, and the bolt hole cannot be set at position of these cavities. The bigger width of cavities 4,5,6, the better thermal insulation. Vice versa.

[0007] 2) Installation of Energy-saving Hollow Sheet [0008] According to different requirements on thermal insulation, thickness of the above energy-saving hollow sheet can vary in a fairly big range (For the specific way to determine its thickness, paragraph 0114 of Patent CN105507432A may be referenced: On the basis of different climates and the building's aimed insulating level or heat transmission coefficient, the structure and thickness of materials at every part of the building shall be determined. For the hollow sheet, preliminary calculation on the overall thickness of its cavities and heat conductivity of the air not in a state of convection shall be done, with specific experiments made, so that it can be assured that the heat transmission coefficients of every part of the building match each other, avoiding bottle necks. At the same time, the heating conditions at different parts of the building shall be examined, with adjustments done accordingly, e.g. At the roof under the hot sun, the thermal insulating requirement shall be higher than that of the external wall; At position of a stove inside the room, the thermal requirement is also higher than elsewhere). If its insulation level needs to be raised to that of an insulated brick wall, its thickness would be several times greater than the traditional hollow sheet (but its weight could be roughly kept unchanged). Under these circumstances, the screws used for installation of traditional hollow sheet would not work, bolt and bolt nut, etc. would need to be used. What's more, due to the limited service time of hollow sheet (usually it cannot surpass 20 years), it needs to be replaced in time according to its specific service time. For convenience of its installation and replacement, easier and faster installation methods need to be developed. See details in the later part Concrete Implementation Methods.

[0009] 3) Door and Window [0010] When using the energy-saving hollow sheet, it's needed to use energy-saving door and window whose thermal insulation performance match the hollow sheet. In the patent mentioned above, the door and window with any layer of cavities addable can meet this requirement. When manufacturing this type of door and window using materials of poly carbonate etc., according to the specific requirements on structural strength, function of transparency, and insulating level, the structures in figure 1 or 3 in the previous text can be applied (For convenience, in the following text they are called structure A and structure B respectively). For door and window with anti-burglary requirement, steel net, metal grid, etc. can be installed on the door and window's rigid frame.

Brief Description of Drawings [0011] Figures 1,2 are Hollow Sheet With Insulating Structure;

[0012] Figure 3 is Hollow Sheet With Combination of Insulating Structure and Spacing Bar Structure;

[0013] Figure 4 is Rain-proofing Connection of Upper and Lower Hollow Sheets;

[0014] Figure 5 is Rain-proofing Connection of Left and Right Hollow Sheets;

[0015] Figure 6 is Rain-proofing of Bolt Hole For Outdoor Installation;

[0016] Figure 7 is Rain-proofing of Bolt Hole For Indoor Installation;

[0017] Figure 8 is Connecting Rod Outside Floor;

[0018] Figure 9 is Rain-proofing of Insulating Block;

[0019] Figures 10,11 are Adjustment of Insulating Block at Position of Connecting Rod;

[0020] Figures 12, 13 are Combination of Vertical Rain Cover and Horizontal Insulating Block;

[0021] Figure 14 is Installation of Rain Cover on Vertical Frame of multiple-storey buildings.

Concrete Implementation Methods [0022] 1) Outdoor Installation:

[0023] A) When the frames of a house, stadium, conservatory, etc. have been constructed, structure A and structure B described in the previous text can be installed onto the frames. According to the thermal expansion coefficient of the hollow sheet’s material, the diameter of bolt hole 5 in figure 1 needs to be bigger than the diameter of bolt and has enough space for the hollow sheet’s displacement caused by thermal expansion. At the same time, the bolt nut needs to have a gasket or blocking plate with a dimension bigger than the bolt hole (otherwise the bolt would not be able to fix the hollow sheet). Also, between two neighboring hollow sheets there shall be set a space enough for their expansion. In these respects there are already a lot of experiences and techniques for reference. The difference here is that the energy-saving hollow sheet may be much thicker than the traditional one, so bolts of corresponding lengths need to be fixed to the building’s frame through bolt nuts, welding, etc.

[0024] B) For convenience of the hollow sheet’s installation and replacement, when it is installed outdoors, its rain-proofing can be done as follows:

[0025] a) When the hollow sheet is installed vertically or obliquely (usually as a wall it is installed vertically; as a roof it is installed obliquely), at where the upper and lower hollow sheets connect, the section in figure 4 can be applied: At the lower brim of upper hollow sheet 1 there is set a covering plate 2. If covering plate 2 needs to be made stronger, ribs 3 can be set on it at intervals. Covering plate 2 can cover the upper brim of lower hollow sheet 4, so that the rain cannot enter the space between hollow sheet 1 and 4. The bigger width of covering plate 2, the better function of rain-proofing. During installation, lower hollow sheet 4 needs to be installed before upper hollow sheet 1. When the above covering plate is applied on the roof, the roof cannot be set level, but should have a slope (Angle of this slope shall be determined according to the maximum rainfall of the area).

[0026] b) The connection of left and right hollow sheets can be done as in the top view of figure 5: Rain cover 1 is fixed by bolt 2 to the building’s frame (For rain-proofing of the bolt hole in the rain cover, see section c in the following text) ; Hollow sheets 3, 4 have rain-proofing plate 5,6 respectively; Between hollow sheets 3,4 there is enough space for expansion; When the hollow sheets expand or shrink, rain-proofing plates 5, 6 can move within the space under rain cover 1; Rain cover 1 and rain-proofing plates 5,6 can prevent the rain from entering the space between hollow sheets 3, 4. The shape of rain cover 1 has some resemblance to the U-shaped locker of current techniques. The difference is that the U-shaped locker can be locked onto the curved edge of two neighboring hollow sheets while the hollow sheets at the two sides of rain cover 1 have no curved edge and the rain cover cannot be locked. Furthermore, the hollow sheets can freely move under the rain cover, and inside the rain cover there needs to be set an insulating layer to reach the same insulating level as the hollow sheets.

[0027] During installation, the upper rain cover shall be aligned with the lower rain cover, and at the lower brim of the upper rain cover there shall be set a covering plate, which covering plate shall cover the upper brim of the lower rain cover, in a similar way to the connection of upper and lower hollow sheets. If under special circumstances the upper and lower rain covers cannot be aligned, then at the upper end of the rain cover there needs to be set a slant plate, which slant plate needs to be connected to under the covering plate of the hollow sheet above it; At the same time, at the lower end of the rain cover there needs to be set a covering plate to cover the upper brim of the hollow sheet under it. [0028] c) Rain-proofing of the bolt hole can be done as in figure 6: Bolt 1 is fixed to the building’s frame; Rain-proofing ring 2 (which can be made with the same material as the hollow sheet) is fixed by welding or gluing on hollow sheet 3 (or on a rain cover) around bolt hole 4; The diameter of rain-proofing ring 2’s bottom is smaller than its top so that the rain running on hollow sheet 3 cannot enter the rain-proofing ring; Near the top of bolt 1 there is set stopping panel 7 which is fixed by bolt nuts 5, 6; Stopping panel 7 and the supports under hollow sheet 3 can prevent hollow sheet 3 from vertically moving, but allow it to move horizontally (Inside rain-proofing ring 2 there is space, so bolt 1 is not wrapped by rain-proofing ring 2. Therefore, although hollow sheet 3 is connected to rain-proofing ring2 to form one body, hollow sheet 3 can still move in the front-back and left-right directions); Stopping panel 7 needs to cover rain-proofing ring 2, and on bolt nut 6 there must be installed insulating cover 8 and rain-proofing cap 9 (They may be fixed by glue if necessary); Rain-proofing cap 9 can prevent the rain from entering the bolt hole at the middle of stopping panel 7; Stopping panel 7 can prevent the rain from entering rain-proofing ring 2; Thus the rain would not be able to enter the bolt hole in hollow sheet 3.

[0029] C) With structure A described in the previous text (see figure 1), the cavities are closed. When the ambient temperature changes, the difference of air pressure can make the hollow sheet convex or concave. If the cavities are opened to the outside, then the vapor may mist the cavities, affecting its function of transparency. To solve this problem, the cavities can be connected to air-bags: When the cavities are heated, the expanded air would be discharged into the air-bags; When the cavities are cooled, the air in the air-bags would be sucked into the air-bags. If the cavities are filled with inert gas, its thermal insulating function can be further improved. With structure B described in the previous text (see figure 3), the cavities can be set as half-closed: When there is a difference of air pressure, the air can move into or out of the cavities through small holes or filtering panels; When there is no difference of air pressure, the air would not move into or out of the cavities.

[0030] D) For highly energy-saving buildings, if the energy-saving hollow sheets are installed outdoors, the frame of building should be totally covered by the hollow sheets, avoiding as much as possible that any part be uncovered. Also, the bolt nuts on the hollow sheets and the part of bolts protruding above the hollow sheets shall be securely covered by insulating caps or sheaths, with structural adhesive used if necessary. Adjacent hollow sheets must be sealed: Between the hollow sheets and the frame of building there shall be installed gasket of neoprene etc., so that the hollow sheets can move but keep being sealed. At the inner side of the outermost panel in the hollow sheet there shall be added a anti-thermal-radiation and anti-ultraviolet coating (This coating can also be added at other layers of panel. But it shall be avoided to make the coating on the hollow sheet’s surface, so as to avoid that the coating be scared or fall off). The hollow sheet’s fire rating and content of hazardous substances, etc. must also meet the related standards.

[0031] 2) Indoor Installation:

[0032] A) Single-storey Building [0033] When installing the hollow sheets indoors for a single-storey building, the methods are similar to that of outdoor installation described above. The differences are:

[0034] a) When the hollow sheets are installed as the roof, they are hung under the frame of the roof with the bolts pointing downward. Rain-proofing needs to be done near the root of the bolts to prevent that the rain flow along the bolt into the room. When the hollow sheets are installed as the external wall, the bolts point inward, and rain-proofing also needs to be done near their root. The rain-proofing can be done as in figure 7: Near the root of bolt 1 is set a spherical surface 2; The top of stopping panel 3 is set as a convex; At the root of this convex there is a rain groove 4. Push Stopping panel 3 to spherical surface 2 and use bolt nut 5 to make it fixed. At the same time, on hollow sheet 6 set rain-proofing ring 8 around bolt hole 7 (in the same way as in figure 6). Then push hollow sheet 6 upward to let bolt 1 enter bolt hole 7. Next add gasket and bolt nut at the lower end (or the inner end) of bolt 1, so that hollow sheet 6 would be fixed under the frame of roof (or inside the frame of external wall), and the rain would be prevented from entering bolt hole 7. At the lower end or inner end of bolt 1 there shall be installed a insulating cap.

[0035] b) When the hollow sheets are installed as the external wall, every upper row of hollow sheets shall be installed before the lower row. Otherwise, the lower row would block the covering plate of the upper row (see figure 4) .

[0036] c) When the rain cover (see figure 5) is installed between the neighboring left and right hollow sheets, the rain cover shall be installed first (at this time the direction that the bolt points in is opposite to that in figure 5, and is the same as the direction of the bolt in figure 7). Then the hollow sheets at the two sides shall be installed (This order of installation is the inverse of that with outdoor installation).

[0037] d) With single-storey buildings, when the hollow sheets are installed indoors, they do not need to cover the frame of building, so different visual effects can be created, yet their thermal insulating performance won’t be second to that of outdoor installation.

[0038] B) Multiple-storey Building [0039] For multiple-storey buildings, indoor installation is more significant, because replacement of the hollow sheets, which have a relative short service life, is much more easily and safely carried out indoors than outdoors on the higher floors of the building. For indoor installation and replacement of hollow sheets on multiple-storey buildings, on the basis of the methods with single-storey as described above, the following adjustments need to be made:

[0040] a) Based on the patent mentioned in the previous text, in figure

8, outside a multiple-storey building’s floor there shall be installed connecting rods 1, 2 (Due to the light weight of hollow sheet, these connecting rods do not need to be directly pre-embedded in the concrete frame of building, but can be fixed onto relatively sparse pre-embedded bolts etc.). Connecting rods 1,2 are respectively inserted in the bolt holes of upper hollow sheet 3 and lower hollow sheet 4; Their rain-proofing can be done as per what’s described above (see Indoor Installation Aa). The curved shape of the connecting rods can further prevent the rain from entering the room.

[0041] b) Based on the patent mentioned in the previous text, in figure

9, outside a multiple-storey building’s floor there shall be installed insulating block 1; At the top and bottom of insulating block 1’s inner side there shall be respectively set rain-proofing plates 2, and a covering plate 3. At the same time, on upper hollow sheet 4 there shall be set covering plate 5 through gluing, welding, etc. ; Covering plate 5 shall be set at the same height as the top of rain-proofing plate 2 and its lower brim shall be elastic and lower than the top of rain-proofing plate 2. During installation, insulating block 1 shall be installed first; Then install the upper and lower hollow sheets. When installing the upper hollow sheet, its bolt hole shall be put onto the connecting rod (see description in the previous paragraph), then it shall be pushed outward till the lower brim of covering plate 5 is pushed against the top of rain-proofing plate 2 and is bent. Then continue with the outward pushing till covering plate 5 surpasses rain-proofing plate 2 and its lower brim restores the original shape, so that the rain would not be able to flow into the space between the hollow sheet and the insulating block. When the hollow sheet has been pushed to the limit, install gasket, bolt nut, and insulating cap at the end of the bolt. The bigger width of covering plate 5 and its lower brim, the better function of rain-proofing. But the rigid part of covering plate 5 needs to be set at a position a little higher than the top of rain-proofing plate 2; Otherwise covering plate 5 might not be able to surpass rain-proofing plate 2 smoothly or might cause damage. At the same time, the bottom of covering plate 5’s rigid part shall be set slanting outward, so shall the top of insulating block Γ s top be set. In this way, their function of rain-proofing can be further improved. When removing the hollow sheet, the insulating cap, bolt nut, and gasket shall be removed first; Then pull the hollow sheet inward (On the inner side of the hollow sheet there shall be set handles for the pulling).

[0042] At position of the connecting rods described above (at part a), the insulating block described in the previous paragraph needs to be made wider and thicker (If the connecting rods are horizontally close to each other, the whole insulating block may be made wider and thicker) with space set at its inner side, so that the connecting rods can be covered (see the front view in figure 10: Insulating block 1 needs to be made wider and thicker at the connecting rods’ positions la, lb). At the same time, the insulating block’s rain-proofing plate 2 and the covering plate of the hollow sheet above it shall be set along its side line 3 (see the front view in figure 10). At position of the side line’s vertical part 3a, there shall be set on rain-proofing plate 2 a brim 3b pointing outward (see the enlarged top view in figure 11), so that the rain would be prevented from flowing to the inside.

[0043] At where the horizontal insulating block and the vertical rain cover meet (see Outdoor Installation Bb and figure 5), vertical rain cover 1 can bend outward (see the side view in figure 12 and the front view in figure 13), so that it can cover insulating blocks 2,3 at its two sides. [0044] c) The rain cover described in the previous text (see Outdoor Installation Bb and figure 5) needs to be installed at the outside of the building’s vertical frame (Because the vertical frame has only a limited width, the installation can still be done indoors. See the top view in figure 14, wherein rain cover 2 is installed outside frame l).0n a same floor, installation of the rain cover need to be done prior to that of the hollow sheet. And, as in figure 14, according to the width of the building’s vertical frame 1, rain cover 2 needs to have adjustments accordingly, so that it can surpass frame 1 at the two sides and hollow sheets 3, 4’s rain-proofing plates 5, 6 can move in the space at the inner side of rain cover 2.

io [0045] d) On the top floor of a multiple-storey building, installation and replacement of the hollow sheets for the roof can be directly done indoors.

[0046] e) Based on the technology of the patent mentioned in the previous text, at the edge of the floor of and above the second storey there must be installed safety railing or safety net (If the hollow sheet has a panel strong enough and is installed securely enough, then the safety railing or net may be canceled). At positions with Anti-burglary requirement, there shall be installed anti-burglary net. On every hollow sheet, insulating block, rain cover, etc. there must be moulded the time of production, and they must be replaced in time.

[0047] f) This energy-saving hollow sheet can also be used as partition wall inside the building. With the cancel of spacing bars, its sound-insulating function can improved.

[0048] 3) Application of Energy-saving Hollow Sheet [0049] The energy-saving hollow sheet used on multiple-storey buildings has a weight times lower than glass curtain wall, yet has higher strength and lower risk of breakage or falling off. Therefore, it can significantly increase the overall height of a building, and can be widely applied on residential buildings, office buildings, hotels, etc. , resulting in higher efficiency of land use and further-decreased price of housing.

[0050] When the energy-saving hollow sheet is applied on houses with frame of reinforced concrete, as the bearing wall is canceled, to ensure the house’s anti-seismic function, the horizontal beam’s span must not be set too long, and shear walls or counter-shear structures shall be set. If steel structure is selected for the house’s frame, its anti-seismic function can be improved. With whatever type of structural frame, an ordinary high-rise building must not be designed to look like a pen. Otherwise its foundation would not suffice to resist the horizontal wave in a earthquake. Only when the ratio of the building’s area of foundation to its height is made large enough, and proportion of the building’s length and width are suitable, avoiding narrow and straight types whose shape in top view is like the longitudinal section of a stick, and applying the types with shape of a square, a cross, etc. in top view---can the building’s anti-seismic function be assured.

[0051] When the energy-saving hollow sheet is applied on various types of building, any level of thermal insulation can be achieved, and the problem of energy-saving can be fundamentally solved, resulting in the comprehensive benefits in the long run.

Claims

1 .An energy-saving hollow sheet whose spacing bars between the multiple panels are totally canceled; whose positions of screw hole have cylinders of certain thickness mounted by directly moulding, gluing, assembling, etc.; whose panels have frame at their brim; whose panels' distances and positions to each other are fixed by the above cylinders and frames with the distances between the panels controllable and the number of panel layers addable thereby, resulting in a thermal insulating performance able to reach any level; whose cancel of the spacing bars can bring a transparency same to glass curtain walls.

2. The energy-saving hollow sheet according to claim 1, wherein the spacing bars and the insulating structures are combined: at the outer layers the cavities have spacing bars so as to keep the structural strength; at the inner layers the cavities have no spacing bar so as to bring the insulating function; the numbers of outer layers for structural strength and that of the inner layers for insulation function can be adjusted according to the specific requirements on strength and insulation.

3. The energy-saving hollow sheet according to claim 1, wherein a rain cover is set between two hollow sheets in left-and-right connection: the rain cover is fixed to the building's frame with sufficient space at the inner side of rain cover for expansion of the hollow sheets; at the edge of the hollow sheets there are set rain-proofing plates to prevent the rain from entering the space between the hollow sheets; at the lower brim of the upper rain cover there is set a covering plate to cover the upper brim of the lower rain cover.

4. The energy-saving hollow sheet according to claim 1, wherein the bolt hole has a rain-proofing ring: the diameter at the bottom of the rain-proofing ring is smaller than at its top, so as to prevent the rain from surpassing the rain-proofing ring.

5. The energy-saving hollow sheet according to claim 1, which can be used in a multiple-storey building: the floors of the building have insulating blocks with a rain-proofing plate and a covering plate respectively set at the top and bottom of the insulating block; at the same time, the hollow sheet above the floor has a covering plate set near its lower side, which covering plate has an elastic lower brim with a height lower than the top of the rain-proofing plate on the insulating block; during installation of the hollow sheet, when it is being pushed outward, the lower brim of its covering plate surpasses the top of the rain-proofing plate on the insulating block and then restores its original shape, so as to prevent the rain from entering the space between the hollow sheet and the insulating block; also, the bottom of the rigid part of the hollow sheet's covering plate is set slanting outward, so is the top of the insulating block set, thus further improving their rain-proofing function.