Abstract
A blower box for thermal prestressing of glass panes, includes a stationary part having a cavity and a gas feed line connected to the cavity, and at least one closure element having a plurality of nozzles connected to the cavity for applying an air flow to a surface of a glass pane, wherein the at least one closure element is connected to the stationary part at least via a connection element of variable length, and the at least one closure element is movable relative to the stationary part such that the distance between the closure element and the stationary part is variable, and the blower box is equipped with a system for moving the at least one closure element.
Claims
1. Blower box for thermal prestressing of glass panes, comprising a stationary part having a cavity and a gas feed line connected to the cavity, and at least one closure element having a plurality of nozzles connected to the cavity for applying an air flow to a surface of a glass pane, wherein the at least one closure element is connected to the stationary part at least via a connection element of variable length, the at least one closure element is movable relative to the stationary part such that a distance between the closure element and the stationary part is variable, and the blower box is equipped with means for moving the at least one closure element.
2. The blower box according to claim 1, wherein the connection element is a bellows.
3. The blower box according to claim 2, wherein the bellows is made of canvas, leather, or steel with a thickness of 0.5 mm to 3 mm.
4. The blower box according to claim 1, wherein the connection element is implemented as a rigid tube and wherein the connection element and the stationary part are telescopically guided into one another and displaceable relative to one another.
5. The blower box according to claim 4, wherein the tube is made of sheet metal with a material thickness of 0.5 mm to 3 mm.
6. The blower box according to claim 1, wherein the connection element is attached directly or indirectly to the closure element.
7. The blower box according to claim 1, which has a single closure element that is a nozzle plate and is connected to the stationary part by means of a single connection element.
8. The blower box according to claim 1, which has a plurality of channels connected to the cavity, which are in each case completed with a nozzle strip opposite the cavity as a closure element, wherein each nozzle strip is connected to the channel associated therewith via a connection element of variable length.
9. The blower box according to claim 8, wherein the nozzle strips are rigidly connected to one another such that the nozzle strips are movable together.
10. Apparatus for thermal prestressing of glass panes, comprising: a first and a second blower box according to claim 1, which are arranged opposite one another such that the closure elements of the first blower box and of the second blower box point toward one another; and means for moving a glass pane into an intermediate space between the first blower box and the second blower box.
11. The apparatus according to claim 10, wherein the means for moving the glass pane comprise a frame mould, on which the glass pane is arranged, and a transport system for moving the frame mould.
12. Method for thermal prestressing of a glass pane, comprising: (a) areally arranging a heated glass pane having two primary surfaces and a circumferential side edge between a first and a second blower box according to claim 1 such that the two primary surfaces can be impinged upon by a gas flow; (b) bringing the closure elements of the first and second blower boxes near the glass pane, and (c) impinging a gas flow upon the two primary surfaces of the glass pane by means of the first and second blower boxes such that the glass pane is cooled.
13. The method according to claim 12, wherein in step (b), the stationary parts of the first and second blower boxes remain stationary.
14. The method according to claim 12, wherein the glass pane is bent along two spatial directions.
15. A method comprising utilizing a glass pane prestressed by the method according to claim 1 in means of transport for travel on land, in the air, or on water.
16. The method according to claim 15, wherein the glass pane is a window pane in a rail vehicle or a motor vehicle.
17. The method according to claim 15, wherein the glass pane is a rear window, a side window or a roof panel of a passenger car.
Description
[0061] They depict:
[0062] FIG. 1 a perspective view of a first embodiment of the blower box according to the invention,
[0063] FIG. 2 a cross-section perpendicular to the nozzle strips through a blower box according to the invention,
[0064] FIG. 3 a cross-section lengthwise of the nozzle strips through a blower box according to the invention,
[0065] FIG. 4 a perspective view of a nozzle strip,
[0066] FIG. 5 a cross-section through the nozzle strip of FIG. 4,
[0067] FIG. 6 a detailed view of a single channel with a nozzle strip and a first embodiment of the connection element,
[0068] FIG. 7 a detailed view of a single channel with a nozzle strip and a second embodiment of the connection element,
[0069] FIG. 8 a detailed view of a single channel with a nozzle strip in another embodiment of the invention,
[0070] FIG. 9 a detailed view of a single channel with a nozzle strip in another embodiment of the invention,
[0071] FIG. 10 a cross-section through two blower boxes according to the invention as part of an apparatus according to the invention for thermal prestressing,
[0072] FIG. 11 a cross-section through an apparatus according to the invention during a prestressing operation
[0073] FIG. 12 a perspective view of another embodiment of the blower box according to the invention,
[0074] FIG. 13 a cross-section through the blower box of FIG. 12, and
[0075] FIG. 14 a flowchart of an embodiment of the method according to the invention.
[0076] FIG. 1 depicts a perspective view of an embodiment of the blower box 1 according to the invention for thermal prestressing of glass panes. The blower box 1 has an inner cavity, out from which channels 4 extend. The outlet opening of each channel 4 is connected via a connection element 6 of variable length to a nozzle strip 5 that functions as a closure element and completes the channel 4. The connection elements 6 are manufactured as tubes from a steel sheet with a material thickness of, for example, 1.5 mm. Each connection element 6 is telescopically connected to the associated channel 4: connection element 6 and the boundary of the channel 4 are thus guided into one another and are displaceable relative to one another. The nozzle strips 5 are rigidly connected to each other by cross-braces 8 and movable together in order to change the distance between the nozzle strips 5 and the channels 4, with the connection elements 6 of variable length ensuring that the gas flow out of blower box 1 is maintained. In order to set the desired distance between nozzle strips 5 and channels 4, the blower box 1 has means 7 for moving the nozzle strips 5. These are realised in the form of four servomotors that are in each case arranged at a corner of the blower box 1, and they drive cylinders that are connected to a nozzle strip 5 or to the cross-brace 8. A movement of the cylinder displaces the totality of the nozzle strips 5 away from or toward the blower box 1.
[0077] The nozzle strips 5 are depicted straight for simplicity and improved clarity. However, for prestressing bent vehicle windows, bent nozzle strips 5 are used in reality, wherein the curved area that is spanned by the nozzle openings is adapted to the contour of the glass pane. When the glass pane is positioned as intended relative to the blower box 1, the nozzle strips 5 can be brought near the glass pane surface by the servomotors and displaceable cylinders, with the stationary part of the blower box 1 remaining stationary. For moving the relatively light nozzle strips 5, significantly less powerful servomotors are necessary than for moving the entire blower box 1, as is common with prior art apparatuses. The blower box is, consequently, more economical. In addition, the stationary part of the blower box 1 can be used as a universal tool, wherein during conversion to a different pane type, only the nozzle strips 5 with the connection elements 6 have to be changed out. It is thus not necessary to produce and store a separate blower box for each type of pane and to reinstall one with each retooling. This, as well, it is advantageous in terms of costs and flexibility of the prestressing apparatus.
[0078] FIG. 2 and FIG. 3 depict cross-sections through a blower box 1 according to the invention similar to that of FIG. 1, wherein the cut surface in FIG. 2 extends perpendicular to the channels 4 and in FIG. 3 lengthwise of the channels 4. The blower box 1 is of the type that is described, for example, in DE 3924402 C1 or WO 2016054482 A1. The blower box 1 has an inner cavity 2, into which an air flow, represented in the figures by a grey arrow, is guided via a gas feed line 3. The air flow is generated, for example, by two fans (not shown) connected in series that are connected to the blower box 1 via the gas feed line 3. The air flow can be interrupted by a closing flap 12 without having to turn off the fans.
[0079] Opposite the gas feed line 3, channels 4, through which the air flow is divided into a row of partial flows, connect to the cavity 2. The channels 4 are implemented in the manner of a hollow rib that is substantially as long as the cavity 2 in one dimension and have, in the dimension perpendicular thereto, a significantly small width, for example, approx. 11 mm. The channels 4 with their elongated cross-section are arranged parallel to one another. The number of channels 4 depicted is not representative and serves only to illustrate the operating principle.
[0080] The cavity 2 is wedge-shaped—along a first dimension, the depth of the cavity 2 is greatest in the centre of the blower box and decreases outward in both directions. In the second dimension, perpendicular thereto, the depth at a given position of the first dimension remains constant in each case. The channels 4 are connected to the wedge-shaped cavity 10 along said first dimension. Consequently, they have a depth profile complementary to the wedge shape of the cavity 2, wherein the depth is least in the centre of the channel 4 and increases outward such that the air outlet of each channel 14 forms into a smooth, planar, or curved surface.
[0081] FIG. 2 and FIG. 3 depict two cross-sections with an angle of 90° relative to one another. FIG. 2 depicts a cross-section along said second dimension of the blower box 1 transverse to the orientation of the channels 4 such that the individual channels 4 are discernible in the cross-section. The depth of the cavity 2 is constant in the sectional plane. FIG. 3 depicts a cross-section along said first dimension of the blower box 1 along the orientation of the channels 4. Here, the wedge-like depth profile of the cavity 2 is discernible, whereas only one single channel 4, whose depth profile is likewise discernible, lies in the sectional plane.
[0082] Each channel 4 is completed on its end opposite the cavity 2 with a nozzle strip 5. Here as well, the nozzle strips 5 are depicted straight for the sake of simplicity, although, in reality, they are curved. The nozzle strip 1 again divides the air flow of each channel 4 into further partial flows, which are fed in each case through a nozzle 9. In order to be able to vary the distance of the nozzle strips 5 from the channels and and to nevertheless maintain the intended air flow, the nozzle strips 5 are connected to the channels via connection elements 6 of variable length. The connection elements 6 are implemented as tubes made of sheet steel that are telescopically connected to the channels.
[0083] FIG. 4 and FIG. 5 each depict a detail of an embodiment of the nozzle strip 5 according to the invention for a blower box 1 for thermal prestressing of glass panes, depicted straight instead of curved here again for the sake of simplicity. The nozzle strip 5 is made of aluminium, which can be readily processed and has advantageously low weight. The nozzle strip has, for example, a width of 11 mm, with the dimensions coordinated to complete the gas channels 4 of an associated blower box 1. As usual with generic nozzle strips, the nozzle strip 5 according to the invention is also implemented with a row of nozzles 9. Each nozzle 9 is a passage (bore) between two opposite side surfaces of the nozzle strip 5. The nozzles 9 are intended to feed a gas flow out of the associated blower box 1, wherein the gas flow enters the nozzle 9 via a nozzle inlet 10 and exits the nozzle 9 via a nozzle opening 11. The side surface of the nozzle strip 9 with the nozzle inlets 10 must, consequently, face the blower box 1 in the installation position, whereas the side surface with the nozzle openings 11 faces away from the blower box.
[0084] The individual nozzles 9 have a greatly widened nozzle inlet 10, followed by a tapering section. Thereafter, the diameter of the nozzle remains constant at 6 mm all the way to the nozzle opening 11.
[0085] FIG. 6 depicts a cross-section of a single channel 4 with an associated nozzle strip 5, which are telescopically connected to one another. For this, the connection element 6 is implemented as a tube and plugged into the channel 4 such that it is displaceable relative to the channel 4. Alternatively, it is also possible to plug the tube onto the channel such that it is arranged outside the channel boundary. The latter variant can even be preferable because, then, a cross-sectional narrowing in the flow direction, as depicted, does not occur and the gas flow is interfered with less.
[0086] FIG. 7 depicts a cross-section of a single channel 4 and an associated nozzle strip 5, which are connected to one another by means of a bellows as a connection element 6. The bellows is connected on one side to the nozzle strip 5 and on the other side to the outlet opening of the channel 4. The bellows is made of canvas with a material thickness of 0.5 mm. Thus, sufficient gas-tightness to maintain the air flow largely without interference is achieved.
[0087] In the exemplary embodiments of FIGS. 6 and 7, the connection element 6 is directly attached to the nozzle strip 5.
[0088] FIG. 8 depicts a cross-section of a single channel 4 and an associated nozzle strip 5 in another embodiment. In contrast to FIG. 7, the bellows, as connection element 6, is not attached directly to the nozzle strip 5. Instead, a gas channel formed from metal sheets is arranged between the connection element 6 and the nozzle strip 5. The connection element 6 is attached to the end of the metal sheets, whereas the opposite end of the metal sheets is attached to the nozzle strip. The gas channel 16 is moved together with a nozzle strip.
[0089] FIG. 9 depicts a cross-section of a single channel 4 and an associated nozzle strip 5 in another embodiment. Here again, the bellows, as connection element 6, is not attached directly to the nozzle strip 5. Instead, the connection element 6 is attached to a fixing element 17 for the nozzle strip 5. The fixing element 17 is implemented in the manner of a fastening rail, into which the nozzle strip is inserted. For this, the nozzle strip is equipped with a complementary rail element. This rail element can be made in one piece with the nozzle strip or, as shown, be attached to the nozzle strip as a separate element.
[0090] FIG. 10 depicts an embodiment of the apparatus according to the invention for thermal prestressing of glass panes. The apparatus comprises a first, upper blower box 1.1 and a second, lower blower box 1.2 that are arranged opposite one another such that the nozzle openings 11 of the nozzle strips 5 are directed at one another. The apparatus further comprises a transport system 13, with which a glass pane I to be prestressed can be transported between the blower boxes 1.1, 1.2. The glass pane I is held horizontally on a frame mould 14, which has a frame-like support surface on which a circumferential edge region of the glass pane I is placed. The transport system 13 consists, for example, of rails or a roller system, on which the frame mould 14 is movingly held. The glass pane I is, for example, a pane made of soda lime glass that is intended as a rear window for a passenger car. The glass pane I has passed through a bending process wherein it had been been brought at a temperature of approx. 650° C., for example, by gravity bending or press bending into the intended, bent shape. The transport system 13 serves to transport the glass pane I, in the still heated state, from the bending apparatus to the prestressing apparatus. There, the two primary surfaces are impinged upon by an air flow by the blower boxes 1.1, 1.2 in order to cool them greatly and, thus, to generate a characteristic profile of tensile and compressive stresses. The thermally prestressed glass pane I is suitable as so-called “single-pane safety glass” for use as an automobile rear window. After prestressing, the pane is again transported by the transport system 13 out of the intermediate space between the blower boxes 1.1, 1.2, making the prestressing apparatus available for prestressing the next glass pane. The transport direction of the glass pane I is represented by a grey arrow.
[0091] FIG. 11 depicts an apparatus according to the invention in steps during the prestressing method according to the invention. The glass pane I to be prestressed is three-dimensionally bent, as is common in the motor vehicle sector. Consequently, it is necessary to move the nozzles 9 of the blower boxes 1.1, 1.2: from a state farther apart in which the glass pane I can be moved into the intermediate space, into a state in which the nozzle openings 11 are at a distance from the glass surface that is as small as possible and substantially constant over the surface of the pane. In prior art apparatuses, this movement occurs through raising and lowering the entire blower boxes with powerful servomotors.
[0092] In contrast, with the apparatus according to the invention, the entire blower boxes 1.1, 1.2 do not have to be moved, only the nozzle strips 5. Initially, the nozzle strips 5 of the two blower boxes are spaced far apart such that there is a large intermediate space into which the glass pane I can be easily transported in (FIG. 11a). When the glass pane I is positioned, the nozzle strips 5 are moved toward the glass pane I (FIG. 11b). All nozzle strips 5 are then arranged at a short distance from the glass surface and the glass pane I is impinged upon by the air flow for prestressing. Then, the nozzle strips 5 are again moved away from the glass pane I such that it can be transported out of the intermediate space.
[0093] In the figure, it is readily discernible that due to the bowl-shaped, three-dimensional curvature of the glass pane I, it would have been impossible to move it into the intermediate space in the final state of the nozzle strips, as a result of which movement of the nozzles is necessary.
[0094] FIG. 12 and FIG. 13 each depict a detail of a blower box 1 with a simpler design, to which the invention is also applicable. Here, the stationary part of the blower box 1 comprises a cover, within which a cavity 2 is formed and to which a gas feed line 3 is connected. Within the stationary part, no division of the gas flow into channels 4 is done, but, rather, the cover has an opening with a large cross-section opposite the gas feed line 3. Used as a movable closure element is a single nozzle plate 15, which closes the large opening and is provided with a two-dimensional pattern of nozzles 9. The nozzle plate 15 is connected to the stationary part by means of a single bellows as connection element 6 of variable length.
[0095] The nozzle plate 15 is also depicted planar here for the sake of simplicity, although, in reality, nozzle plates that are adapted to the contour of the curved vehicle panes, i.e., are also bent three-dimensionally, are used.
[0096] In the embodiment depicted, the connection element 6 is attached directly to the nozzle plate 15. However, it is also possible here for additional elements to be arranged between the connection element 6 and the nozzle plate 15, for example, a gas channel 16 formed by metal sheets or eine fixing element 17 for the nozzle plate, as depicted in FIGS. 8 and 9 in connection with a nozzle strip 5.
[0097] FIG. 14 represents an exemplary embodiment of the method according to the invention for thermal prestressing of glass panes with reference to a flowchart using an apparatus according to FIGS. 10 and 11.
LIST OF REFERENCE CHARACTERS
[0098] (1) blower box [0099] (1.1) first/upper blower box [0100] (1.2) second/lower blower box [0101] (2) cavity of the blower box 1, 1.1, 1.2 [0102] (3) gas feed line of the blower box 1, 1.1, 1.2 [0103] (4) channel/nozzle web of the blower box 1, 1.1, 1.2 [0104] (5) nozzle strip (as a closure element) [0105] (6) connection element of variable length [0106] (7) means for moving the closure elements [0107] (8) cross-brace of the nozzle strips 5 [0108] (9) nozzle [0109] (10) nozzle inlet/inlet opening of the nozzle 9 [0110] (11) nozzle opening/outlet opening of the nozzle 9 [0111] (12) closing flap in the gas feed line 3 [0112] (13) transport system for glass panes [0113] (14) frame mould for glass panes [0114] (15) nozzle plate (as a closure element) [0115] (16) gas channel between the connection element 6 and the closure element [0116] (17) fixing element between the connection element 6 and the closure element [0117] (I) glass pane
