Patent Application
20200376816
The invention relates to a heatable vacuum ring, its use in a method for deaerating a stack sequence, and a method for deaerating a stack sequence.
Stack sequences can be used in particular for producing a composite pane or a solar generator.
Composite panes are widely used, for example, as vehicle panes, such as windshields, side windows, rear windows, or roof panels in vehicles on water, on land, or in the air, but also as architectural panes, as fire protection panes, as safety glazing, or in furniture as well as movable or permanently mounted furnishings.
Composite panes typically comprise at least two panes, for example, a substrate pane and a cover pane joined together via at least one thermoplastic intermediate layer, for example, made of a thermoplastic polyvinyl butyral (PVB) film, in a lamination process under the action of heat and pressure.
Solar generators typically comprise solar cells, thermoplastic films arranged on the top and bottom sides thereof, and two outer glass panes joined together under the action of heat and pressure.
Both with composite panes and with solar generators, it is generally desirable to avoid bubbles between the respective layers of the stack sequence during the respective manufacturing process and/or to remove existing bubbles between the respective layers in order to improve the quality of the product.
Industrially common methods for producing composite panes usually include a deaeration process combined with an autoclave process, as disclosed in U.S. Pat. Nos. 2,948,645 and 4,781,783. For production of solar generators as well, a deaeration process is usually combined with an autoclave process, as disclosed in DE 3544080 A1. The prior art methods are very energy intensive since, therein, the entire stack sequence is heated to seal an edge region of the deaerated stack sequence.
The object of the present invention consists in providing an improved vacuum ring that enables deaerating a stack sequence and heating it locally in the region of the side edge of the stack sequence and/or in a region adjacent the side edge, and, thus, sealing it under a vacuum.
The object of the present invention is accomplished according to the invention by a vacuum ring in accordance with the independent claim 1. Preferred embodiments are apparent from the dependent claims.
The term “stack sequence” refers here and in the following in particular to a stacked arrangement of panes and thermoplastic films or a stacked arrangement of panes, solar cells, and thermoplastic films, for example, a stack sequence for producing a composite pane or a solar generator. Particularly preferably, a “stack sequence” means a stack sequence for producing a composite pane, i.e., a stack sequence comprising at least two panes and at least one intermediate thermoplastic film.
The invention relates to a vacuum ring for deaerating a stack sequence. The vacuum ring according to the invention comprises a vacuum-stable flexible hose that can be connected to a vacuum pump. The hose has the shape of a closed ring. According to the invention, the hose is open to the interior, i.e., it has an opening to the interior of the ring formed by the hose. The hose can be arranged around an outer side edge of a stack sequence such that the outer side edge of the stack sequence is held in the opening of the ring. The hose of the vacuum ring can thus be placed circumferentially around the stack sequence on the outer side edge of a stack sequence. The opening of the hose is implemented such that the outer side edge of the stack sequence can be held such that a deaeration channel is formed. For example, the opening of the hose can have a substantially pentagonal shape. However, a C-shaped or U-shaped opening is, for example, also possible.
The vacuum ring according to the invention completely encloses the side edges of the stack sequence and the intermediate space between the individual panes and/or films of the stack sequence and seals it using vacuum technology. As a result of applying a vacuum to the vacuum ring, the air can be removed from the deaeration channel and from the intermediate space between the individual panes and/or films.
According to the invention, the vacuum ring has at least one electric heating element and is thus a heatable vacuum ring. The vacuum ring can, for example, have one, two, three, four, five, six, or more heating elements.
As used here and below, the term “heating element” refers to an electrical component that converts electrical energy into thermal energy, i.e., heat.
Preferably, the electric heating element has a connection element for connecting to a voltage source. The connection of the connection element to the voltage source can be made with or without contact. In the case of a contactless connection, the voltage of the voltage source is induced in the connection element.
The connection element can have any shape suitable for connecting to a voltage source. It can, for example, be a plug connection or a plate in which voltage can be induced.
As a result of the application of a voltage on the electric heating element, the heating element and also, consequently, the region of the hose adjacent the heating element are heated. The region of the stack sequence that is arranged adjacent the heated regions of the hose and/or of the heating element is likewise heated thereby. Consequently, the at least one thermoplastic film of the stack sequence is also heated in this region and melts or softens at a sufficient temperature of, for example, 70° C. to 100° C. In this way, the panes of the stack sequence can be joined together in this region and sealed airtightly. If the electric heating element has a connection element for connecting to a voltage source, the voltage is applied to the electric heating element by connecting the connection element to a voltage source.
In one embodiment, the electric heating element is at least partially embedded in the hose, more precisely, in the mass of the hose, and/or glued to the hose.
Preferably, the electric heating element is at least partially embedded in the hose.
In an advantageous embodiment, the electric heating element is completely enclosed by the material of the hose.
In a preferred embodiment, the electric heating element extends over the entire length of the hose. This embodiment enables complete sealing of the stack sequence in the region adjacent the side edge. It can thus be insured that air cannot again penetrate between the individual layers of the stack sequence after it has been evacuated and sealed.
In another embodiment, individual electric heating elements are arranged in or on the hose in individual sections of the hose in each case. In this manner, selective heating of individual sections of the hose and, thus, section-wise sealing of the stack sequence can be achieved.
The electric heating element can have any suitable form. Preferably, the electric heating element is implemented in the form of a wire or strip.
A heating element implemented as a wire preferably has a diameter between 0.05 mm and 5 mm, particularly preferably between 0.1 mm and 3 mm, most particularly preferably between 0.3 mm and 2 mm, for example, 1 mm.
A heating element implemented as a strip preferably has a width between 5 mm and 12 mm, particularly preferably between 6 mm and 10 mm, most particularly preferably between 7 mm and 9 mm, for example, 8 mm or 5 mm. The thickness of a heating element implemented as a strip preferably is between 0.01 mm and 2 mm, particularly preferably between 0.01 mm and 0.5 mm, most particularly preferably between 0.03 mm and 0.1 mm, for example, 0.05 mm or 0.1 mm.
The dimensions of the hose, i.e., the size of the opening and the length of the hose, are adapted to the thickness and the circumference of the stack sequence to be deaerated. The wall thickness of the hose is adapted to the thickness and the number of heating elements and is preferably 3 mm to 10 mm, particularly preferably 5 mm to 7 mm.
In advantageous embodiments, the electric heating element is implemented as a-wave-shaped, meander-shaped, or spiral-shaped wire or a wave-shaped, meander-shaped, or spiral-shaped strip.
A wave-shaped, meander-shaped, or spiral-shaped embodiment has an advantageous effect on the flexibility and the durability of the heating element. In the case of expansion of the material of the hose, heating elements thus implemented can be deformed accordingly without kinks or breaks occurring.
In one embodiment, the electric heating element is arranged directly adjacent the opening of the hose. In this case, the heating element can come into direct contact with the stack sequence to be deaerated during evacuation of the vacuum ring. Preferably, the heating element does not come into contact with the outer side edge of the stack sequence to be deaerated.
In an advantageous embodiment, the electric heating element is arranged such that when the outer side edge of the stack sequence is held in the vacuum ring, the heating element is arranged outside, in particular completely outside, the deaeration channel formed in the evacuated state. This ensures that the electric heating element does not make contact with the side edge of the stack sequence.
Making contact with the side edge of the stack sequence that has a thermoplastic intermediate layer could result in the fact that upon heating of the heating element and evacuation of the vacuum ring, the thermoplastic intermediate layer is partially sucked into the deaeration channel and/or the heating element is bonded to the thermoplastic intermediate layer emerging from the stack sequence. In addition, making contact with the side edge could result in a poor seal between the vacuum ring and the stack sequence, resulting in poor deaeration of the stack sequence upon heating of the heating element and evacuation of the vacuum ring.
In one embodiment, the electric heating element is made of a metal or a metal alloy. Preferably, the electric heating element is made of copper, a copper alloy, a nickel alloy, a nickel-copper alloy, or a nickel-chromium alloy. Particularly preferably, the electric heating element is made of copper or a copper alloy. The electrical heating element can, for example, be a copper wire, a copper strip, or a wire or strip made of a copper alloy.
The electric heating element can, optionally, be at least partially coated with at least one insulating layer. Nonconductive lacquers and/or plastics are in particular suitable as an insulating layer. The insulating layer can, for example, prevent or at least minimize damage to the heating element, such as corrosion and the like. Furthermore, an insulating layer can serve to prevent a user of the vacuum ring from being able to come into direct contact with the current-carrying parts of the vacuum ring.
In one embodiment, the electric heating element is completely enclosed by an insulating layer. In an alternative embodiment, the heating element is only partially coated with an insulating layer.
As a result of application of a suitable voltage, i.e., by connection of the heating element to a voltage source, the electric heating element can heat up. In one embodiment, the electric heating element heats up, upon application of a voltage, to 20° C. to 160° C., preferably to 50° C. to 150° C., particularly preferably to 70° C. to 130° C., most particularly preferably to 90° C. to 110° C., for example, to 100° C.
As described above, the connection of the heating element to a voltage source can be accomplished, for example, in that the heating element has a connection element and this is connected with or without contact to the voltage source.
In an advantageous embodiment, the vacuum ring has at least two electric heating elements, wherein at least one electric heating element is arranged in or on the hose above the opening of the hose and at least one electric heating element is arranged in or on the hose below the opening of the hose. For example, the vacuum ring can have exactly two electric heating elements, of which one is arranged above and one below the opening. The vacuum ring can, however, also have four electric heating elements, of which two are arranged above and two below the opening. In another embodiment, the vacuum ring has six electric heating elements, of which three are arranged above and three below the opening.
In an advantageous embodiment, the vacuum-stable flexible hose of the vacuum ring according to the invention is made of an elastomer. For example, the hose can be made of silicone, rubber, or synthetic rubber, in particular ethylene-propylene-diene rubber (EPDM).
The vacuum ring according to the invention can be connected to the vacuum pump via a vacuum hose. Optionally, a vacuum compensation tank can be arranged between the vacuum hose and the vacuum pump. The vacuum ring and the vacuum hose can, for example, be connected to one another via a tee inserted into the vacuum ring. Preferably, the combination of the vacuum ring and the vacuum hose is implemented in one piece.
The at least one heating element can be electrically connected to a voltage source, in particular via a connection element as previously described. In the case of more than one heating element, the heating elements can either all be connected to the same voltage source or to different voltage sources, wherein multiple heating elements are preferably connected to the same voltage source.
Together, the vacuum ring, vacuum hose, optional vacuum compensation tank, vacuum pump, and the at least one electrically connected voltage source form a vacuum system according to the invention.
In one embodiment of the vacuum system, the vacuum hose with the vacuum pump connected via an optional vacuum compensation tank and the at least one voltage source are arranged on the same side of the vacuum ring, preferably adjacent one another. In another embodiment of the vacuum systems, the vacuum hose with the vacuum pump connected via an optional vacuum compensation tank and the at least one voltage source are arranged on opposite sides of the vacuum ring. In principle, the arrangement of the vacuum hose with the vacuum pump connected via an optional vacuum compensation tank and the arrangement of the at least one voltage source can be done independently of one another at any position on the vacuum ring.
In the embodiment in which the electric heating element has a connection element for connecting to a voltage source, the vacuum hose with the vacuum pump connected via an optional vacuum compensation tank and the connection element for connecting to a voltage source are arranged on the same side of the vacuum ring, preferably adjacent one another. In another embodiment of the vacuum system, the vacuum hose with the vacuum pump connected via an optional vacuum compensation tank and the connection element for connecting to a voltage source are arranged on opposite sides of the vacuum ring. In principle, the arrangement of the vacuum hose connected to the vacuum pump connected via an optional vacuum compensation tank and the arrangement of the connection element for connecting to a voltage source can be done independently of one another at any point on the vacuum ring.
The vacuum compensation tank has, for example, a volume of 1 m3. The vacuum pump has, for example, a pumping capacity of 300 m3/h and reaches a maximum final pressure of 0.1 mbar.
The invention also relates to a method for deaerating a stack sequence, at least comprising arranging a stack sequence, arranging a vacuum ring according to the invention around the outer side edge of the stack sequence, applying a vacuum, i.e., a negative pressure, to the vacuum ring, and applying a voltage to the at least one electric heating element, which the vacuum ring according to the invention has. As a result of applying a negative pressure of, for example, at least −0.9 bar to the vacuum ring, the air between the layers of the stack sequence is removed. The electrical energy of the voltage source is converted into thermal energy by the electric heating element and the heating element heats up. As explained in detail above, this also locally heats up the stack sequence and the at least one thermoplastic film contained therein such that the stack sequence is bonded together in this region. The application of a vacuum and the application of a voltage on the at least one heating element can even be carried out simultaneously.
The embodiment, in which the application of a vacuum and the application of a voltage on the at least one heating element occur simultaneously, is a particularly preferred embodiment of the method according to the invention.
In one embodiment, a voltage is applied to the electric heating element that is suitable for heating the electric heating element to 20° C. to 160° C., preferably to 50° C. to 150° C., particularly preferably to 70° C. to 130° C., most particularly preferably to 90° C. to 110° C., for example, to 100° C.
The invention also includes the use of a vacuum ring according to the invention in a method for deaerating a stack sequence, wherein the stack sequence is in particular a stack sequence for producing a composite pane or a solar generator.
The panes of the stack sequence preferably contain glass, particularly preferably flat glass, even more preferably float glass, and in particular quartz glass, borosilicate glass, soda lime glass, or clear plastics, preferably rigid clear plastics, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyesters, polyvinyl chloride, and/or mixtures thereof. The panes are preferably transparent, in particular for the use of the composite pane produced from the stack sequence as a windshield or rear window of a vehicle or other uses in which high light transmittance is desirable. In the context of the invention, “transparent” refers to a pane having transmittance greater than 70% in the visible spectral range. For panes that are not within the traffic-relevant field of vision of the driver, for example, for roof panels, the transmittance can however also be much lower, for example, greater than 5%.
The thickness of the panes can vary widely and thus be adapted to the requirements of the individual case. Preferably used are standard thicknesses from 0.5 mm to 25 mm, preferably from 1.4 mm to 2.5 mm for vehicle glass, and preferably from 4 mm to 25 mm for furniture, appliances, and buildings, in particular for electric radiators. The size of the panes can vary widely and is governed by the size of the application. The panes have, for example, in vehicle construction and architecture, customary areas from 200 cm2 up to 20 m2.
The panes of the stack sequence are joined to one another by at least one intermediate layer. The intermediate layer is preferably transparent. The intermediate layer preferably contains at least one plastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and/or polyethylene terephthalate (PET). The intermediate layer can, however, also contain, for example, polyurethane (PU), polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl methacrylate, polyvinyl chloride, polyacetate resin, casting resins, acrylates, fluorinated ethylene propylene, polyvinyl fluoride, and/or ethylene tetrafluoroethylene, or copolymers or mixtures thereof.
The intermediate layer can be formed by one or also by a plurality of films arranged above one another, wherein the thickness of a film is preferably from 0.025 mm to 2 mm, typically 0.38 mm or 0.76 mm or 1.52 mm. In other words, the intermediate layer can in each case be constructed from one or a plurality of films. Preferred in this case are at least three films arranged above one another, in particular polyvinyl butyral films, with alternating different plasticity or elasticity, as are known, for example, from EP 0763420 A1 or EP 0844075 A1.
The intermediate layers can preferably be thermoplastic, and, after heating, bond the panes and any further intermediate layers to one another.
The total thickness of the stack sequence to be deaerated is preferably between 2 mm and 30 mm.
Vacuum rings according to the invention adapted to the size of the panes of the stack sequence with openings adapted to the total thickness of the stack sequence to be deaerated ensure that the vacuum ring according to the invention completely encloses the side edges of the stack sequence and the intermediate space between the individual panes and/or films of the stack sequence and seals it using vacuum technology.
Vacuum rings according to the invention can, for example, be produced by placing the at least one electric heating element and then extruding the mass of the hose around it. This production method is suitable in particular for vacuum rings according to the invention, in which the at least one electric heating element is at least partially embedded in the mass of the hose.
Vacuum rings according to the invention, in which the at least one electric heating element is glued onto the mass of the hose, can, for example, be produced by first producing the hose using an extrusion method, and then gluing the at least one electric heating element onto the hose with a temperature-resistant adhesive.
The various embodiments of the invention can be realized individually or in any combinations. In particular, the features mentioned above and explained below can be used not only in the combinations indicated, but also in other combinations or in isolation without departing from the scope of the present invention.
It goes without saying that the embodiments described for an electric heating element can, in those cases in which the vacuum ring has more than one electric heating element, be transferred to the respective number of electrical heating elements.
The invention is now explained in detail using exemplary embodiments and referring to the accompanying figures. The figures in no way restrict the invention. In a simplified, not to scale representation, they depict:
It goes without saying that in the embodiments depicted in
The method includes, in a first step I, arranging a stack sequence 2. In a second step II, the method includes arranging a vacuum ring 1 according to the invention around the outer side edge 5 of the stack sequence 2. In a third step III, the method includes applying a vacuum to the vacuum ring 1. In a fourth step IV, the method includes applying a voltage to the electric heating element 7. Steps III and IV can even be carried out simultaneously.
| Number | Date | Country | Kind |
|---|---|---|---|
| 17205823.2 | Dec 2017 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2018/083275 | 12/3/2018 | WO | 00 |
