Micro pillar for vacuum glass and vacuum glass

Abstract

The present invention provides a micro-pillar for vacuum glass and vacuum glass. The micro-pillar includes a plurality of fiber layers, each fiber layer is composed of a plurality of metal fibers and / or alloy fibers. The present invention also provides a vacuum glass, wherein a plurality of the micro-pillars are arranged in the vacuum chamber of the vacuum glass. The new micro-pillar material and structure innovatively developed by the present invention uses a flexible micro-support made of metal fibers and / or alloy fibers, so that the new micro-pillar can greatly reduce heat transfer, improve sound insulation performance, and effectively enhance the effects of heat insulation and sound insulation; at the same time, the micro-pillar can also support the vacuum layer, and when the glass is impacted, the micro-pillar needs to be overcome to do work. By utilizing the compression performance of the micro-pillar of the present invention, the kinetic energy can be converted into the internal energy of the pillar, and no stress concentration point that increases instantly is formed, which can effectively reduce the risk of glass breakage.

Description

Technical Field

[0001] The invention relates to a micro-pillar for vacuum glass and vacuum glass, belonging to the technical field of vacuum glass. Background Art

[0002] As an excellent energy-saving material, vacuum glass has good development and application prospects in terms of thermal insulation and other aspects. Vacuum glass refers to a glass product in which two or more sheets of flat glass are separated by supports and sealed around the periphery to form a vacuum layer between the glasses. The thickness of the vacuum cavity is generally controlled at 0.1-0.5mm. The supports are usually arranged in a square array and separated. One of the sheets of glass has an exhaust hole. After the vacuum is exhausted, the exhaust hole is sealed to form a vacuum cavity. In order to maintain the long-term stability of the vacuum degree, the vacuum layer usually has a built-in getter.

[0003] Vacuum glass has a high vacuum degree and can effectively prevent the conduction of heat and sound, thus playing a good role in heat insulation and sound insulation. It is a top-level light-transmitting, heat-insulating and sound-insulating material. Figure 1 As shown, there are three heat transfer mechanisms of vacuum glass: ① Radiation heat transfer C 辐射 ② Heat transfer of support C 支撑物 ③ Residual gas heat transfer C 气 . An effective way to reduce radiation heat transfer is to use Low-e glass. The lower the emissivity of Low-e glass, the better. As long as the vacuum degree is ensured, the residual gas heat transfer can be reduced to a negligible level. Normally, the residual gas in the vacuum chamber is controlled to be less than 0.1Pa; the remaining main heat transfer is the tiny supports. The propagation of sound requires a medium. There is no way to propagate sound in a vacuum environment without a medium. Therefore, the vacuum chamber can effectively prevent the propagation of sound. However, vacuum glass is connected by supports, which can form a sound bridge. The vibration of the first glass is transmitted to the second glass through the supports, and the second glass also vibrates. The greater the rigidity of the support, the stronger its vibration transmission ability, which leads to a significant decrease in the sound insulation performance of the vacuum glass.

[0004] At present, the mainstream supports for vacuum glass on the market are mainly ① ceramic supports and ② alloy supports. The alloy supports are represented by stainless steel, and their heat transfer coefficient is about 17W / m·K. The heat transfer coefficient of ceramic supports is mostly above 2.7W / m·K. The heat transfer coefficient is relatively high, and they are rigid and have strong vibration transmission capabilities, which can easily reduce the sound insulation performance. Vacuum glass relies on supports to resist the atmospheric pressure outside the glass. Each support is under very high pressure and is a stress concentration point. When the glass is impacted by external force, the alloy and ceramic supports are very rigid and deform very slightly, and cannot effectively absorb energy, and the risk of glass breakage rises sharply. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a micro-pillar for vacuum glass, which is made of metal fiber and / or alloy fiber and has good sound insulation and heat insulation effects.

[0006] To achieve the above object, the present invention first provides a micro-pillar for vacuum glass, wherein the micro-pillar includes a plurality of fiber layers, each of which is composed of a plurality of metal fibers and / or alloy fibers.

[0007] According to a specific embodiment of the present invention, different fiber layers may be composed of fibers with the same wire diameter, or may be composed of fibers with different wire diameters.

[0008] According to a specific embodiment of the present invention, preferably, the wire diameter of the metal fiber is 2 μm-40 μm, and the wire diameter of the alloy fiber is 2 μm-40 μm.

[0009] According to a specific embodiment of the present invention, preferably, the height of the micro-pillar is 0.2-2.0 mm.

[0010] According to a specific embodiment of the present invention, the total thickness of the micro-pillar can be controlled by the number of layers and the size of the wire diameter. Preferably, the micro-pillar includes 3-10 fiber layers, more preferably 5 layers.

[0011] The bottom surface (or back surface) of the micro-pillar of the present invention can be a flat surface, which can play a fool-proof role, effectively prevent the micro-pillar from standing when being arranged, and improve the production yield of vacuum glass. According to a specific embodiment of the present invention, preferably, the bottom surface of the micro-pillar is rectangular, circular or elliptical, and the top is curved.

[0012] According to a specific embodiment of the present invention, the diameter of the micro-pillar can be designed according to actual needs, and is generally 0.4mm-1mm; preferably, when the bottom surface of the micro-pillar is circular, the diameter of its cross-section is 0.4mm-1mm; when the bottom surface of the micro-pillar is rectangular, the length and width of the bottom surface are 0.4mm-1mm respectively; the rectangle referred to in the present invention also includes a square, and the length and width at this time refer to the side length of the square; when the bottom surface of the micro-pillar is elliptical, the major axis length of its bottom surface is 0.4mm-1mm.

[0013] According to a specific embodiment of the present invention, preferably, in the micro-pillar, at least some of the fibers that are in contact with each other form a spot welding effect. By sintering the fibers that are in contact with each other together to form a spot welding effect, the micro-pillar can have a firm structure, is not easy to delaminate, and is elastic.

[0014] According to a specific embodiment of the present invention, preferably, the material of the metal fiber includes one or a combination of two or more of tungsten, nickel, aluminum, and copper;

[0015] According to a specific embodiment of the present invention, preferably, the material of the alloy fiber includes one or a combination of two or more of stainless steel, tungsten alloy, nickel alloy, aluminum alloy and copper alloy.

[0016] According to a specific embodiment of the present invention, preferably, the thermal conductivity of the micropillar is 0.001-3 W / (m·K); more preferably, it is 0.01 W / (m·K).

[0017] According to a specific embodiment of the present invention, preferably, the air permeability of the micropillar is ≥30 L / (min·dm 2 ), preferably 30-100 L / (min·dm 2 ). The air permeability is tested in accordance with ISO 4022 "Permeability of sintered metallic materials. Determination of the permeability to liquids".

[0018] According to a specific embodiment of the present invention, preferably, the density of the micropillar is 0.0015-0.0045 g / mm 3 ; preferably 0.0025g / mm 3 .

[0019] Some physical parameters of the fiber cloth made of ultrafine stainless steel fibers provided by the present invention are shown in Table 1. The micro-pillars made of the fiber cloth include 3-10 layers, the wire diameter of the stainless steel fibers is 2 μm-40 μm, the bottom surface is circular, the bottom diameter is 0.65 mm, and the height is 0.4 mm.

[0020] Table 1

[0021] Thermal conductivity W / (m·K) <![CDATA[Air permeability L / (min.dm 2 )]]> <![CDATA[Density (g / mm 3 )]]> 0.01 ≥30 0.0025

[0022] The micro-pillars provided by the present invention have good toughness, strength and compressibility. They will not delaminate or break when compressed. After the external force is eliminated, they will recover to a certain thickness by virtue of the elasticity of the fibers. When a number of micro-pillars are arranged on a glass plate, after vacuuming, the atmospheric pressure on the vacuum glass is borne by all the micro-pillars and the surrounding packaging walls of the vacuum glass. At this time, the support will be compressed. The greater the pressure, the greater the compression, and the compression ratio will increase accordingly. After the pressure is released, they can rebound to a certain thickness. The micro-pillars can still maintain elasticity when compressed by external forces.

[0023] According to a specific embodiment of the present invention, preferably, the compression ratio of the micro-pillar is 60%. The compression ratio is calculated according to the following formula:

[0024] Compression ratio = (height before compression - height after compression) / height before compression x 100%.

[0025] According to a specific embodiment of the present invention, preferably, the elastic modulus of the micropillar is 440 MPa.

[0026] According to a specific embodiment of the present invention, preferably, the rebound ratio of the micro-pillar is 20%. The rebound ratio is calculated according to the following formula:

[0027] Rebound ratio = (height after decompression - height after compression) / height after compression × 100%.

[0028] The relevant parameters of some micro-pillars of specific structures provided by the present invention are shown in Table 2. Among them, these micro-pillars are made of stainless steel fibers, including 5 layers, the wire diameter of the stainless steel fibers is 5 μm-25 μm, and the bottom surface is round.

[0029] Table 2

[0030]

[0031]

[0032] The fiber structure of the micro-pillar provided by the present invention can be manufactured by sintering into a sheet of the size of A4 paper or a large area, or by rolling into a coil. For example, it can be manufactured by the following method (such as Figure 2 shown):

[0033] Firstly, metal fibers and / or alloy fibers are laid together to form a composite structure having several layers, and then sintered at high temperature to form a fiber cloth, and fibers that are at least partially in contact with each other are sintered together to form a spot welding effect;

[0034] The fiber cloth is formed into the required micro-pillars by using a punching die or other processing methods.

[0035] The present invention also provides a vacuum glass, wherein a plurality of micro pillars provided by the present invention are arranged in a vacuum cavity of the vacuum glass.

[0036] According to a specific embodiment of the present invention, preferably, in the vacuum glass, the spacing distance between the micro-pillars is not less than 10 mm; more preferably, the spacing distance between the micro-pillars is 30-60 mm.

[0037] According to a specific embodiment of the present invention, preferably, in the vacuum glass, the height of the vacuum cavity is less than 0.4 mm; more preferably, the height of the vacuum cavity is 0.15-0.35 mm.

[0038] According to a specific embodiment of the present invention, the size of the micro-pillars used for vacuum glass should be uniform; preferably, in vacuum glass, the range of the bottom surface size of the micro-pillars is <0.02 mm. Wherein, when the bottom surface of the micro-pillar is circular, the bottom surface size here refers to the diameter of its bottom surface; when the bottom surface of the micro-pillar is rectangular, the bottom surface size here refers to the length and width of its bottom surface (when the rectangle is a square, the bottom surface size refers to its side length); when the bottom surface of the micro-pillar is elliptical, the bottom surface size here refers to the long axis length of its bottom surface.

[0039] The new micro-pillar material and structure innovatively developed by the present invention uses flexible tiny supports made of metal fibers and / or alloy fibers, so that this new micro-pillar can greatly reduce heat transfer, improve sound insulation efficiency, and effectively enhance the effects of heat insulation and sound insulation; at the same time, the micro-pillar can also support the vacuum layer, and when the glass is impacted, it is necessary to overcome the work done by the micro-pillar. By utilizing the compression performance of the micro-pillar of the present invention, kinetic energy can be converted into the internal energy of the pillar, without forming an instantaneously increased stress concentration point, which can effectively reduce the risk of glass breakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the heat transfer mechanism of vacuum glass.

[0041] Figure 2 Schematic diagram of the preparation process of the micro-pillar of the present invention.

[0042] Figure 3 A schematic diagram of the structure of the micro-pillar provided in the embodiment.

[0043] Figure 4 Schematic diagram of the thermal resistance of vacuum glass. DETAILED DESCRIPTION

[0044] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0045] Example Micropillars made of alloy fibers

[0046] This embodiment provides a micro-pillar made of alloy fiber, and its structure is as follows Figure 3 shown.

[0047] The micro-pillar is made of stainless steel fiber, and the micro-pillar includes 5 layers of fiber, wherein the wire diameter of the stainless steel fiber is 5-25 μm;

[0048] The micropillar has a height of 0.4 mm and a circular bottom with a diameter of 0.6 mm.

[0049] Thermal insulation efficiency test

[0050] According to the TL4+0.3V+T4 structure vacuum glass (4mm soda-lime glass coated with Low-e film + 0.3mm vacuum layer thickness + 4mm soda-lime glass without Low-e), actual samples were prepared, using the mainstream stainless steel pillars in the market and the micro-pillars in the embodiment, with a uniform spacing of 30mm×30mm and a uniform diameter of 0.6mm for the support pillars (micro-pillars). First, the analysis was conducted from the perspective of thermal insulation theory (refer to Tang Jianzheng, Vacuum Glass, Wuhan University of Technology Press. 2018.7).

[0051] The thermal resistance of vacuum glass is as follows Figure 4 As shown:

[0052] R 1 is the external glass thermal resistance, R 2 is the inner glass thermal resistance, R 辐射 is the radiation thermal resistance, and the heat conduction of the residual gas in the vacuum glass has been neglected, from which we can get:

[0053] Formula (1)

[0054] Radiation thermal resistance R 辐射 =1 / C 辐射

[0055] Formula (2)

[0056] Where T 1 ,T 2 ——Absolute temperature of the two surfaces (K)

[0057] ε 有效 ——Surface effective radiation rate

[0058] σ——Stefan Boltzmann’s law, its value is 5.67×10 -8 W.M. -2 ·K -4

[0059] ε 有效 =(1 / ε 1 +1 / ε 2 -1) -1

[0060] Where ε 1 ——Hemispherical emissivity of the first surface

[0061] ε 2 ——Hemispherical emissivity of the second surface

[0062] The first glass has a Low-e coating, ε 1 The value is 0.1, the second glass has no Low-e, ε 2Take the value of 0.84 and test according to the test standard: JGJ 151-2008: Indoor temperature T 1 The value is 20+273=293K, the outdoor temperature is T 2 The value is -20+273=253K, and the average temperature is 273K;

[0063] Calculated: C 辐射 =0.45W·m -2 ·k -1

[0064] Formula (3)

[0065] Among them, λ 玻 ——Thermal conductivity of glass, value is 1.0W·m -1 ·K -1 ;

[0066] h——micro-pillar height (m), the value for this structure is 0.0003m;

[0067] a——support radius (m);

[0068] b——the distance between supports (m);

[0069] λ 支撑物 ——Thermal conductivity of the support material, in W·m -1 ·K -1 .

[0070] Stainless steel support 不锈钢支撑物 =17W / m·K, substituting into the formula, C 不锈钢支撑物 =0.643W·m -2 ·k -1 ,but

[0071] R 金属支撑物 =1.56(W -1 ·m 2 ·K).

[0072] Due to the elastic effect, the thermal conductivity of metal fiber supports with different compression amounts is different. The spacing between the points is 30mm×30mm, and the pressure on a single support column is about 90N, with a pressure of 318Mpa. The measured metal fiber support has a thermal conductivity of λ under this pressure. 金属纤维支撑物 =0.625W·m -2 ·k -1 , put it into the formula, C 金属纤维支撑物 =0.33W·m -2 ·k -1 Then R 金属支撑物 =3.03(W -1 ·m 2 K);

[0073] According to Table 3, the thickness of the glass is 4mm, and the thermal resistance is R = 0.005 (W -1 ·m 2 ·K)

[0074] Table 3

[0075]

[0076] Then R 1 =R 2 =0.005(W -1 ·m 2 ·K) into formula (1) to get R 不锈钢真空 =0.92(W -1 ·m 2 ·K)

[0077] R 金属纤维真空 =1.28(W -1 ·m 2 ·K)

[0078] Formula (4)

[0079] Routside——External surface heat transfer resistance (W -1 ·m 2 ·K)

[0080] R Inner-outer surface heat transfer resistance (W -1 ·m 2 ·K)

[0081] U——Heat transfer coefficient (W·m -2 ·K -1 )

[0082] When calculating the U value, each country has different 内 +R 外 The regulations are different, among which China stipulates:

[0083] R 内 +R 外 =1 / 7.6+1 / 19.9=0.1818(W -1 ·m 2 ·K)

[0084] Substituting into formula (4), the heat transfer coefficient U of the metal fiber support column is obtained: 金属纤维 =0.68(W·m -2 ·K -1 ), the heat transfer coefficient U of the stainless steel support column 金属纤维 =0.91(W·m -2 ·K -1 )

[0085] It can be seen that the use of metal fiber support columns can reduce heat transfer by 25%.

[0086] Sound insulation efficiency test

[0087] Sound is generated by the vibration of an object and propagates in the form of sound waves. Sound propagation requires a medium, and the propagation effect can be simply divided into solid>liquid>gas from good to bad. The more rigid and dense the material is, the better the propagation effect. Similarly, when sound propagates to one of the sheets of vacuum glass, it needs to be transmitted to the other sheet through the support column. The weaker the rigidity of the support column, the better the barrier effect. The support column of the present invention is elastic, and the weaker the rigidity, the stronger the sound insulation. Since the ultrafine metal fiber cloth itself is composed of micron-level metal fibers, its weaving direction in the tiny pillars is parallel to the glass plate, that is, perpendicular to the direction of sound propagation, which means that these layered micron fibers have the effect of breaking bridges for heat transfer and sound transmission, which undoubtedly enhances the sound insulation and heat insulation effects.

[0088] The present invention tests the use of metal fiber pillars and stainless steel pillars, T4+0.3V+T4 vacuum structure (4mm thick soda-lime glass + 0.3mm thick vacuum layer + 4mm thick soda-lime glass), size 495mm×495mm, and the sound insulation effect is shown in Table 4:

[0089] Table 4

[0090] NO. Support column material shape Diameter / mm Distribution point spacing / mm Weighted sound insulation / dB 1 Stainless steel Drum 0.65 55 34 2 Metal Fiber cylinder 0.65 30 35

[0091] When sound propagates through vacuum glass, each support column is a sound bridge, and the sound waves are transmitted to the next glass through these support columns. Therefore, the more support columns there are, the more sound bridges there are, and the more obvious the transmission effect is. Under the same area, the number of support columns depends on the spacing between the points. The larger the distance, the fewer the number. As can be seen from Table 4 above, when the metal fiber has a smaller spacing between the points, that is, when the number is larger, the weighted sound insulation is still 3% higher than that of the stainless steel support column. This proves that the flexible micro-pillar with metal fiber cloth as the main body is also significantly superior in sound insulation function.

Claims

1. A micro pillar for vacuum glass, in, The micro-pillar comprises a plurality of fiber layers, each fiber layer being composed of a plurality of metal fibers and / or alloy fibers; The diameter of the metal fiber or alloy fiber is 2 μm-40 μm; the micro-pillar includes 3-10 fiber layers; Different fiber layers are composed of fibers of different wire diameters; when in use, the weaving direction of the fibers is parallel to the glass plate and perpendicular to the direction of sound propagation; In the micropillar, fibers that are at least partially in contact with each other form a spot welding effect.

2. The micropillar according to claim 1, in, The height of the micropillars is 0.2-2.0 mm.

3. The micropillar according to claim 1, in, The bottom surface of the micro-pillar is rectangular, circular or elliptical, and the top surface is curved.

4. The micropillar according to claim 3, in, When the bottom surface of the micro-pillar is circular, the diameter of the bottom surface is 0.4 mm-1 mm; When the bottom surface of the micro-pillar is rectangular, the length and width of the bottom surface are 0.4 mm to 1 mm respectively; When the bottom surface of the micro-pillar is elliptical, the major axis length of the bottom surface is 0.4 mm-1 mm.

5. The micropillar according to claim 1, in, The material of the metal fiber includes one or a combination of two or more of tungsten, nickel, aluminum, and copper; The material of the alloy fiber includes one or a combination of two or more of stainless steel, tungsten alloy, nickel alloy, aluminum alloy and copper alloy.

6. The micropillar according to claim 1, in, The thermal conductivity of the micropillar is 0.001-3W / (m·K).

7. The micropillar according to claim 6, in, The thermal conductivity of the micropillar is 0.01 W / (m·K).

8. The micropillar according to claim 1, in, The air permeability of the micro-pillar is ≥30L / (min·dm 2 ).

9. The micropillar according to claim 8, in, The air permeability of the micro-pillar is 30-100L / (min·dm 2 ).

10. The micropillar according to claim 1, in, The density of the micropillar is 0.0015-0.0045 g / mm 3 .

11. The micropillar according to claim 10, in, The density of the micropillar is 0.0025 g / mm 3 .

12. The micropillar according to claim 1, in, The compression ratio of the micro-pillar is 10-90%.

13. The micropillar according to claim 1, in, The elastic modulus of the micropillar is 50-1500 MPa.

14. The micropillar according to claim 1, in, The rebound ratio of the micro-pillar is 10-50%.

15. A vacuum glass, in, A plurality of micro-pillars as described in any one of claims 1 to 14 are arranged in the vacuum chamber of the vacuum glass.

16. The vacuum glass according to claim 15, in, The spacing distance between the micro pillars is not less than 10 mm.

17. The vacuum glass according to claim 16, in, The spacing distance between the micro pillars is 30-60 mm.

18. The vacuum glass according to claim 15, in, The height of the vacuum chamber is less than 0.4 mm.

19. The vacuum glass according to claim 18, in, The height of the vacuum chamber is 0.15-0.35 mm.

20. The vacuum glass according to claim 15, in, The extreme difference of the bottom surface size of the micro-pillar is less than 0.02 mm.

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