Glazing panel comprising glass sheets linked together via spacers and corresponding production method

Abstract

The invention concerns a glazing panel comprising first (5) and second (5) glass sheets linked together via at least one spacer (8) which holds them a certain distance apart from one another and, between said glass sheets (5), an inner space (4) comprising at least one first cavity (41), in which there is a vacuum of less than 100 mbar and which is closed by a peripheral seal disposed at the periphery of the glass sheets, around said inner space (4), the seal (1) being a metal seal rigidly connected respectively to the first and second glass sheets. According to the invention, the metal seal (1) further comprises at least one hollow metal tube (11) of which a first end (111) communicates with the inner space (4) and a second end (112) communicates with the outside of the panel, the second end (112) comprising means for blocking the tube. According to the invention, the tube comprises at least one gas trap (113) rigidly connected to the inside of the tube (11).

Claims

1. A glazing panel comprising: a first glass sheet and a second glass sheet that are associated together by way of at least one spacer that holds said sheets a certain distance apart, and, between said glass sheets, an internal space comprising at least one first cavity, in which space there is a vacuum with a pressure of less than 100 mbar, said space being closed with a peripheral impermeable seal placed on a periphery of the glass sheets around said internal space, the impermeable seal being a metal seal securely fastened to the first and second glass sheets, respectively, wherein the metal seal furthermore comprises at least one hollow metal tube, a first end of which communicates with the internal space and a second end of which comprises a plug formed by pinching off the second end of the tube to form a cold weld, and in that the tube comprises at least one getter securely fastened to the interior of the tube.

2. The glazing panel as claimed in claim 1, wherein the getter comprises a coating placed on at least one portion of the internal surface of the tube.

3. The glazing panel as claimed in claim 1, wherein the getter comprises a tubular part provided to be inserted into the tube.

4. The glazing panel as claimed in claim 1, wherein the getter comprises an alloy of the following materials: zirconium; vanadium; and iron.

5. The glazing panel as claimed in claim 1, wherein the metal tube comprises at least one material selected from copper and its alloys, aluminum and its alloys and nickel and its alloys, in an unoxidized state.

6. The glazing panel as claimed in claim 1, wherein the metal seal is securely fastened by soldering to a first peripheral zone of the first glass sheet covered with a first adhesion coating and to a second peripheral zone of the second glass sheet covered with a second adhesion coating.

7. The glazing panel as claimed in claim 2, wherein the metal seal comprises a metal strip drilled with a hole into which the metal tube is placed.

8. A process for manufacturing the vacuum-insulated glazing panel as claimed in claim 1, comprising: associating together the first glass sheet and the second glass sheet by way of the at least one spacer that holds said sheets a certain distance apart, between said glass sheets, closing the internal space with the peripheral impermeable seal placed on the periphery of the glass sheets, around said internal space; and pumping down the internal space in order to obtain a vacuum with a pressure of less than 100 mbar, securely fastening the at least one getter to the interior of the tube; and blocking the second end of the tube by pinching off the end of the tube to form the cold weld once the pumping step has terminated.

9. The process as claimed in claim 8, further comprising coating at least one portion of the internal surface of the tube with the getter.

10. The process as claimed in claim 8, further comprising inserting the getter into the tube.

11. The process as claimed in claim 8, wherein the metal seal is securely fastened by soldering to a first peripheral zone of the first glass sheet covered with a first adhesion coating and to a second peripheral zone of the second glass sheet covered with a second adhesion coating.

12. The process as claimed in claim 8, wherein the metal seal comprises a metal strip, and the process further comprising drilling the strip in order to produce a hole, and inserting the metal tube into the hole.

13. A glazing panel comprising: a first glass sheet; a second glass sheet; at least one spacer that holds said first and second glass sheets apart; an internal space between said glass sheets, said space having a vacuum with a pressure of less than 100 mbar; and an impermeable metal seal placed on a periphery of the glass sheets enclosing said internal space, the impermeable metal seal being fastened to the first and second glass sheets, wherein the metal seal further comprises at least one hollow metal tube having first and second ends, a first end of said tube communicating with the internal space and the second end of the tube comprising a plug formed by pinching off the second end of the tube to form a cold weld, and wherein the tube comprises at least one getter.

14. The glazing panel as claimed in claim 13, wherein the getter comprises a coating placed on at least one portion of an internal surface of the tube.

15. The glazing panel as claimed in claim 13, wherein the getter comprises a tubular part provided to be inserted into the tube.

16. The glazing panel as claimed in claim 13, wherein the getter comprises an alloy of a material selected from the group consisting of zirconium, vanadium, and iron.

17. The glazing panel as claimed in claim 13, wherein the metal tube comprises at least one material selected from the group consisting of copper and its alloys, aluminum and its alloys, and nickel and its alloys, in an unoxidized state.

18. The glazing panel as claimed in claim 13, wherein the metal seal is fastened by soldering to a first peripheral zone of the first glass sheet covered with a first adhesion coating and to a second peripheral zone of the second glass sheet covered with a second adhesion coating.

19. The glazing panel as claimed in claim 13, wherein the metal seal comprises a metal strip having a hole into which the metal tube is placed.

Description

5. LIST OF FIGURES

(1) Other features and advantages of the invention will become more clearly apparent on reading the following description of a preferred embodiment, given simply by way of nonlimiting illustrative example, and from the appended drawings, in which:

(2) FIG. 1 shows a schematic of a vacuum-insulated glazing panel according to one embodiment of the invention;

(3) FIG. 2 shows a peripheral impermeable seal of the panel in FIG. 1 according to one embodiment of the invention;

(4) FIG. 3 illustrates a process for manufacturing a glazing panel according to one embodiment of the invention.

6. DESCRIPTION OF ONE EMBODIMENT OF THE INVENTION

(5) The present invention will be described with reference to particular embodiments and with reference to certain drawings; however, the invention is not limited thereby and is limited only by the claims. In the drawings, the size and relative dimensions of certain elements may have been exaggerated and not drawn to scale for the sake of illustration.

(6) In addition, the terms first, second, third, etc., in the description and in the claims are used to distinguish between similar elements and not necessarily to describe a sequence whether it be temporal, spatial, for the sake of classification or otherwise. Of course the terms thus used are interchangeable in appropriate circumstances and the embodiments of the invention described here are capable of using other sequences than those described or illustrated here.

(7) In addition, the terms high, low, above, below, etc., in the description and claims are used for descriptive purposes and not necessarily to describe relative positions. Of course the terms thus used are interchangeable in appropriate circumstances and the embodiments of the invention described here are capable of being used in other orientations than those described or illustrated here.

(8) It will be noted that the term comprising, used in the claims, must not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It must therefore be interpreted as specifying the presence of the specified elements, units, steps or components referenced, but not excluding the presence or addition of an element, unit, step or component, or group thereof. Therefore the scope of the expression an apparatus comprising the means A and B must not be limited to apparatuses consisting only of components A and B. In other words, as regards the present invention, the only relevant components of the apparatus are the components A and B.

(9) Such as used here and unless otherwise indicated, the term impermeable is understood to mean impermeable to air or any other gas present in the atmosphere.

(10) Such as used here and unless otherwise indicated, the expression thermally insulating layer is understood to mean a layer of metal oxide having an emissivity lower than 0.2, preferably lower than 0.1 and more preferably lower than 0.05. A thermally insulating layer may for example be one of the following layers: Planibel G, Planibel Top N, Top N+ and Top 1.0 sold by AGC.

(11) Such as used here and unless otherwise indicated, the term spacer relates to the one or more elements ensuring a relatively constant distance is maintained between two adjacent glass sheets.

(12) Below, the particular case where a glazing panel according to the invention is a vacuum-insulated glazing panel is considered. Of course, the invention also applies to any type of glazing panel comprising glass sheets (two, three or more) bounding insulating or non-insulating internal spaces (also called multiple glazing panels) provided that a partial vacuum is generated in at least one of these internal spaces.

(13) For example, the invention also applies to a triple glazing panel, a first internal space of which comprises a partial vacuum and a second internal space of which is filled with gas, for example, but not exclusively, dry air, argon (Ar), krypton (Kr), xenon (Xe), sulfur hexafluoride (SF.sub.6) or even a mixture of certain of these gases.

(14) Of course, other variants are envisionable and in particular one of the glass sheets of the panel may be replaced by a laminated glass panel and any other addition or modification may be made.

(15) FIG. 1 shows a view of an entire vacuum-insulated glazing panel according to one embodiment of the invention.

(16) The vacuum-insulated glazing panel comprises first and second glass sheets 5 (for example clear soda-lime-silica glass sheets 6 mm in thickness) that are associated together by way of at least one spacer 8 that keeps them a certain distance apart. Thus, the first and second glass sheets 5 are separated by a first internal space 4 comprising a first cavity 41. In the internal space 4 there is a vacuum with a pressure of less than 100 mbar, for example of less than 1 mbar, for example equal to 10.sup.3 mbar (obtained by pumping the internal space 4 using a vacuum pump).

(17) For example, the internal space is about 1 mm in thickness (of course, the internal space may be any other thickness).

(18) In order to facilitate the pumping, the surfaces of the internal space may be degassed beforehand for example by applying a flow of ozone at above 100 C. to the surfaces of the internal space.

(19) Of course, any other type of glass and thickness of glass may be employed according to the invention.

(20) The vacuum-insulated glazing panel also comprises a plurality of spacers 8 according to the invention, the spacers being sandwiched between the first and second glass sheets 5 so as to maintain the first space between these glass sheets 5.

(21) For example, the spacers are placed between the first and second glass sheets so as to form a grid the pitch of which is comprised between 20 and 80 mm and preferably comprised between 30 and 60 mm.

(22) The spacers 8 may be different shapes, such as cylindrical, spherical, filiform, hour-glass shaped, cruciform, etc.

(23) Below, the context of an example according to the invention in which the spacers 8 are made of AISI301 steel and have a C shape is considered.

(24) The step of forming the austenitic steel first comprises a step of obtaining a wire of cylindrical cross section by drawing. Of course, the step of obtaining the wire may also be obtained by hot extrusion of said AISI301 steel then drawing, allowing the final diameter of the wire to be achieved.

(25) For example, starting with a wire of 5 mm diameter that is then drawn, a thin wire having a diameter of 1 mm (which represents a reduction in the cross section of the wire of 80%) is obtained.

(26) The step of forming the austenitic steel then comprises a step of cutting (for example by means of a wire cutter) at least one portion of the wire in order to form said spacer. For example, the length of said wire portion is 4 mm.

(27) According to one advantageous embodiment, the step of forming the austenitic steel then comprises a step of bending at least one portion of said wire portion so as to form a loop portion the maximum radius of curvature of which is 0.5 mm.

(28) Of course, the bending step may be carried out before the cutting step.

(29) Preferably, the wire portion is a circular portion the radius of curvature of which is 0.5 mm.

(30) Thus, in the context of this second example, the work-hardening step is merged with the drawing step.

(31) Thus, during the drawing operation, the cross section of the wire is decreased by 80% and the strength of the AISI stainless steel is increased from 620 MPa to about 1400 MPa.

(32) For example, if spacers made of non-work-hardened AISI (which therefore have a compressive strength of 620 MPa) that have a contact area equivalent to a disk of 250 m radius are used, spaced apart from one another by 30 mm, the value of the U coefficient of the vacuum-insulating glazing panel obtained is equal to 0.8 W/m.sup.2K.

(33) In contrast, using the aforementioned spacers according to the invention (made of work-hardened AISI 301 and shaped into a C) having a compressive strength of 1400 MPa, the number of spacers may be decreased by separating them by 50 mm while simultaneously improving the U value which is then about 0.5 W/m.sup.2K.

(34) U values are estimated for the vacuum-insulated glazing units based on a glazing unit such as described above, comprising a low-E layer. The thermal transmissions (U values) were evaluated using the method described in the publication of the University of Sydney: DETERMINATION OF THE OVERALL HEAT TRANSMISSION COEFFICIENT (U-VALUE) OF VACUUM GLAZING, T M. Simko, A H. Elmandy and R E. Collins. ASHRAE Transactions, 105, pt 2, p. 1-9. 1999.

(35) In order to further improve performance in terms of thermal insulation, a thermally insulating layer 3 may be placed on an internal surface of at least one of the glass sheets 5.

(36) The two glass sheets 5 are assembled and made gas-tight (ensuring the vacuum) via a peripheral impermeable seal 1 placed on the periphery of the glass sheets 5 around the internal space 4, shutting the first cavity 41. Thus, the peripheral impermeable seal 1 sealably closes (with respect to the gases present outside the internal space) the internal space.

(37) The impermeable seal 1 is a metal seal 1 securely fastened to the first and second glass sheets 5, respectively.

(38) FIG. 2 shows a peripheral impermeable seal 1 of the panel in FIG. 1 according to one embodiment of the invention. FIG. 2 shows only one portion of the cross section of the glazing panel.

(39) For example, the metal seal 1 is securely fastened by soldering (for example by means of a solder based on tin and lead) to a first peripheral zone of the first glass sheet 5 covered with a first adhesion coating 53 and to a second peripheral zone of the second glass sheet 5 covered with a second adhesion coating 53.

(40) The metal seal 1 comprises means 11 for bringing the internal space 4 into communication with the exterior of the panel, the means 11 of communication being blockable. For example, the means of communication comprise a hollow metal tube 11 (the outside diameter of which is for example 4 mm and the inside diameter of which is for example 2 mm) a first end 111 of which communicates with the internal space 4 and a second end 112 of which communicates with the exterior of the panel, the second end comprising means for blocking the tube. Of course, according to one variant of the invention, the means of communication comprise a plurality of such hollow metal tubes (for example two tubes, thereby possibly for example facilitating the pumping of the panel and the implementation of the optional degassing of the surfaces of the internal space of the panel).

(41) For example, the metal seal 1 comprises a copper strip in an unoxidized state. The metal strip is drilled with a hole 12 in which the metal tube 11 is placed. The metal tube 11 is securely fastened to the metal strip by soldering (for example by means of a solder based on tin and lead). For example, the metal tube is made of copper. Of course, it may be made of any other metal or metal alloy, for example of nickel (or one of its alloys), of aluminum (or one of its alloys), etc.

(42) Advantageously, the metal tube 11 is made of oxygen-free high-conductivity (OFHC) grade copper, also referred to as Cu-c2 or even Cu-OFE, and must have undergone an anneal between 650 and 850 C. for 30 minutes under a dry hydrogen atmosphere. Specifically, this treatment is advantageous since the material will undergo a deformation of about 350% during the pinching off. Another type of material that may be used to produce the tube 11 is high-purity nickel, for example Nickel A, NI270, NI200 or even 99.4% nickel according to standard ASTM-B161, for example, the tube 11 may have undergone an anneal at 1150 C. for 30 minutes before being pinched off. Lastly, other materials such as aluminum, pure iron, gold, platinum, silver or even niobium may also be suitable for producing the tube 11.

(43) Advantageously, the metal tube 11 (the outside diameter of which is for example 4 mm and the internal diameter of which is for example 2 mm) comprises a getter 113 securely fastened to the interior of the tube 11.

(44) For example, the getter 113 comprises a tubular part 113 provided to be inserted into the tube. The tubular part 113 may be securely fastened to the tube by adhesive bonding, by soldering or even by force fitting (the outside diameter of the tubular part being chosen depending on the inside diameter of the tube 11 and the fastening technique used).

(45) For example, the getter is a cylindrical product sold by SAES Getter referenced under the name St2002 Pills with a height of 4 mm and an outside diameter of 2 mm in order to be inserted forcefully into the metal tube 11. Thus, the getter 113 consists of an alloy of zirconium, vanadium and iron and is extremely active in the adsorption of all the atmospheric gases, of oxygen and nitrogen and even water vapor, methane, carbon-containing compounds and hydrogen. The optimal activation conditions of this getter are 350 C. for 15 min.

(46) The internal space 4 of the panel also comprises a second cavity 42 placed between the metal seal 1 and the edge face 9 of the panel, the second cavity 42 being closed by the metal seal 1. The first end of the metal tube is contained in the second cavity 4.

(47) For example, the means for blocking the tube 11 comprise a plug formed by pinching off the second end 112 of the tube (of course, according to the invention, any other blocking technique or any other type of plug may be used, for example a metal plug that is screwed, force fitted or soldered to the second end of the tube 112). To pinch off the second end 112 of the tube 11 a pinch-off tool exerting a high pressure on the second end of the tube 11 may for example be used, for example a pinch-off tool sold under the reference Pinch-Off Tool Manual Series (or GST Series or HAC Series) by C. H. Bull Co., or a pinch-off tool sold under the reference HY-187 (or HY-250 or HY-500 or even HY-750, depending on the diameter of the tube 11) Pinch-Off Tool by Custom Products & Services.

(48) Thus, those internal surface portions of the tube 11 which are brought into physical contact by the pinching off bond together atomically, this bonding occurring between atoms in their surface layers, thus producing a cold weld that is very strong and that does not require heat and solder to be used.

(49) The fact that the copper of the tube is in an unoxidized state implies that the internal surface portions of the tube that are brought into physical contact by the pinching off generate more atomic bonds (relative to an oxidized state of the copper), thereby increasing the strength of the cold weld.

(50) For example, the internal surface of the tube is cleaned beforehand (for example ultrasonically) in order to remove contaminants from the surface (which would prevent bonds from being created and therefore decrease the strength of the weld). For example, the internal surface is polished with a 320-grit emery cloth in order to remove possible oxide crystals. The external surface of the tube may also be polished with a 320-grit emery cloth in order to remove possible oxide crystals and thus ensure the aforementioned pinching off works properly.

(51) For example, after the tube 11 has been closed by pinching off the second end 112 of the tube 11, the second end 112 of the tube 11 and the external surface of the tube located on the exterior of the panel may be covered with a protective coating, for example a metal alloy. The second end 112 of the tube 11 may also be protected by means of a plastic cap.

(52) Moreover, the adhesion material forming the adhesion coatings 53 may be selected, for example, from the group composed of copper and its alloys (for example with titanium and/or chromium), aluminum and its alloys, iron and its alloys (such as austenitic FeNi steels: e.g. iron (50-55% by weight, for example 52% by weight), nickel (45-50% by weight, for example 48% by weight), such as alloy 48), the iron alloys comprising the following metals: iron (53-55% by weight, for example 53.5% by weight), nickel (28-30% by weight, for example 29% by weight) and cobalt (16-18% by weight, for example 17% by weight), and Kovar, platinum and its alloys, nickel and its alloys, gold and its alloys, silver and its alloys, gallium arsenide and tin or its alloys. This list not being exhaustive.

(53) Of course, the impermeable metal seal 1 may take any other form, it may for example take the form of steps such as described in patent application WO 2011/061208 A1.

(54) Moreover, it may, for example, be produced by virtue of a solder joint between two metal seal portions, themselves soldered to the glass sheets. Moreover, any other technique for securely fastening the impermeable seal to the void(s) may be used without departing from the scope of the invention, for example a weld obtained by directly welding glass to glass (no adhesion coating 53 is required in this case) or by force fitting.

(55) Of course, according to variants (not illustrated) of the aforementioned embodiment, the glazing panel may furthermore comprise a third glass sheet separated from either one of the first and second glass sheets (for example from the second glass sheet) by a second space in order to form a second cavity.

(56) According to a first variant, a second impermeable seal is furthermore placed on the periphery of the third and second glass sheets in order to form a second (16 mm thick, for example) internal space, said second internal space being filled with at least one gas. The gas may for example be air, argon, nitrogen, krypton, xenon, SF6, CO.sub.2, or any other thermally insulating gas.

(57) According to a second variant, the third and second glass sheets are assembled and made gas-tight (ensuring the vacuum) via an impermeable seal placed on the periphery of the glass sheets, shutting a second internal space, and a plurality of spacers are sandwiched between the third and second glass sheet so as to maintain the second internal space between these glass sheets. Thus a vacuum-insulated triple glazing unit is obtained.

(58) Of course, other variants are envisionable and in particular a glass sheet may be replaced by a laminated glass panel and any other addition or modification may be made.

(59) FIG. 3 shows a process for manufacturing the vacuum-insulated glazing panel in FIG. 1 according to one embodiment of the invention.

(60) The manufacturing process comprises the following steps: associating 301 together the first and second glass sheets 5 by way of at least one spacer 8; closing 302 the internal space 4 (between said glass sheets 5) with the peripheral impermeable metal seal 1 (comprising the metal strip and the hollow metal tube 11, a first end (111) of which communicates with the internal space and a second end (112) of which communicates with the exterior of the panel) placed on the periphery of the glass sheets 5, around said internal space 4; securely fastening the getter 113 to the interior of the tube 11 by coating at least one portion of the internal surface of the tube with the getter (in the case of a getter taking the form of a coating) or by securely fastening (for example by adhesive bonding or by force fitting) the getter 113 into the tube (for example in the case of a getter 113 taking the form of a tubular part provided to be inserted into the tube); pumping down 303 the internal space 4 in order to obtain a vacuum with a pressure of less than 100 mbar, for example of less than 1 mbar, for example 10.sup.3 mbar; and blocking 304 the second end 112 of the tube 11 once the pumping step has terminated, the blockage being obtained by pinching off the second end 112 of the tube 11.

(61) According to the invention, the closing step 302 comprises the following step: securely fastening, by soldering, the metal seal to the first peripheral zone of the first glass sheet covered with a first adhesion coating 53 and to a second peripheral zone of the second glass sheet covered with a second adhesion coating.

(62) The process also comprises a step of drilling the strip in order to produce the hole 12, a step of inserting the metal tube 11 into the hole 12 and, preferably, a step of securely fastening the metal tube to the metal strip by soldering.

(63) Of course, the invention is not limited to the aforementioned example embodiments.