Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B29/00—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins
  • C03B29/04—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way
  • C03B29/06—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way with horizontal displacement of the products
  • C03B29/08—Glass sheets
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/02—Re-forming glass sheets
  • C03B23/023—Re-forming glass sheets by bending
  • C03B23/025—Re-forming glass sheets by bending by gravity
  • C03B23/0252—Re-forming glass sheets by bending by gravity by gravity only, e.g. sagging
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/02—Re-forming glass sheets
  • C03B23/023—Re-forming glass sheets by bending
  • C03B23/035—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending
  • C03B23/0352—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending by suction or blowing out for providing the deformation force to bend the glass sheet
  • C03B23/0357—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending by suction or blowing out for providing the deformation force to bend the glass sheet by suction without blowing, e.g. with vacuum or by venturi effect
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
  • C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
  • C03B35/145—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by top-side transfer or supporting devices, e.g. lifting or conveying using suction

Definitions

• the invention relates to a heating device for windows that are moved flat on a transport mold in a furnace section and a method for heating windows placed on transport molds.
• transport mold also always includes, within the meaning of this description, the means for moving this mold in the furnace section.
• these means are in the form of trolleys equipped with wheels and are moved on rails along the transport routes provided in the furnace section.
• These means may, however, also be carrier frames which are for example moved on rollers or strips.
• transport mold the unit composed of the support mold (generally a skeleton or frame) and the means of transport (the frame supporting the mold, if necessary with its wheels if it is a carriage) of this support mold in the oven - without the drive means (like rollers placed under the frames of moving molds).
• the loading station can be for example at one end (with respect to the flow of material from the beginning) and outside the elongated oven section and the unloading station at its other end and outside also of the oven section.
• the transport molds are loaded with panes, are introduced into the furnace section and pass through it while the panes are heated and bent.
• the transport molds leave the oven section with the panes being finished and the panes are removed in the unloading station connecting to the oven section.
• the transport molds are brought to the outside of the furnace section, from the unloading station to the loading station, where they are again loaded with untreated windows (US 4,778,507, DE2041254A).
• the transport molds necessarily cool. As they are heated again after being loaded into the furnace section, this results in unnecessary energy loss per se which must be compensated for by additional furnace power.
• the problem underlying the invention is to develop a device and a corresponding method of heating and / or bending glass for economic operation.
• a window heating device resting on transport molds this device comprising an oven section for heating the windows and a loading station for loading the oven section; with windows, the loading station being provided with means for introducing the panes into the furnace section and for depositing the panes on transport molds in the furnace section, at the device as claimed by the independent claim of device, and by
• An essential feature of the invention is that the point of transfer of the windows to the loading station on the transport molds is in the heated furnace zone or the furnace section.
• the transport molds therefore do not leave the furnace section, even at the loading station, and therefore therefore remain more or less at the same temperature level.
• the panes are then removed from the outside by an oven door (as small as possible, preferably slit-shaped) on the transport molds remaining in the furnace section. In this way, the latter, in continuous operation of the device, never cool substantially below the prescribed temperature, as would happen in an existing cooling zone.
• the furnace section does not include a cooling zone or a cold section, for example because the windows are provided only around or at their softening temperature (first prior gravity bending) and then removed for other treatment (bending or prestressing), the level of Transport mold temperature can even be kept at a high level almost constant.
• the panes whose treatment is finished are again removed from the transport molds also in the oven section.
• the transport molds do not leave the oven itself at this point (at this point). This leaves at first the freedom to provide or not an empty return path for the transport molds
• the furnace may be two-stage (or sections), the transport molds making a loop circuit, carrying the panes from one end to the other of the furnace to the upper stage, and returning to empty towards the starting end by the lower stage.
• the passage from one stage to another is carried out by means of an elevator at each end of the furnace, each elevator conveying vertically, upwards or downwards as the case may be, a transport mold.
• the loading station and the unloading station are equipped according to the invention so that, for the transfer of the windows in and out of the furnace section, the transport molds must not leave the controlled heating furnace, it may be wise in an alternative embodiment to place the loading and unloading stations very close to each other, that is to say for example also to superimpose them.
• the loading and unloading stations are respectively at one end (end of loading or sampling) of the section of furnace to be considered as a conveyor chain.
• Their spatial proximity has the advantage that each transport mold, just after the removal of a window whose treatment is finished, can to be recharged, so that, compared to a relatively long empty return path in other installations, a very high occupancy rate of the transport molds is obtained. In other words, the transport molds are unoccupied only on a very short part of the loop circuit on which they pass.
• the windows can be removed from the outward or proximity to the inversion zone or at any intermediate point.
• the loading and unloading can be performed substantially at the same horizontal level (as illustrated in FIG. 2).
• the transport molds comprise a frame-shaped contact surface (or support surface) for the windows, the windows being supported only on their peripheral edge.
• the contact surface is generally formed to correspond to a desired bending of the panes. This desired bending may correspond to the final shape of the windows or only at an intermediate stage of the final shape.
• there is a second bending step either by transferring partially curved windows to another transport mold of different shape, so that there may be a final bending step for example using gravity, or it follows a step of bending to the press using other tools.
• Such methods and corresponding devices are known for example from WO2006 / 075117, WO2004 / 087589 or
• the transport molds can also provide two-level bending steps if their frame-shaped contact surfaces are equipped in known manner with pivotable parts which are folded upwards after a first bending of the window brought to softening temperature and impose, especially on the side edges, a curvature close to the edge or local even stronger.
• these means may consist of narrow levers type grapples can grasp the windows by their edges.
• the levers can then be installed for example on a plate or a frame disposed above the panes and movable in at least two axes along the peripheral edge of the panes.
• One of the axes serves for the descent or climb movement and the other axis for the entry and exit movement in or from the furnace section.
• at least three levers must be distributed on the peripheral edge of the windows.
• This type of construction of the transfer means is particularly suitable for the simultaneous loading and setting up of two overlapping windows in coincidence.
• the plates or frames serving as counter-bearings for the reaction forces of the panes can, if necessary, be adapted to the contour and, in the unloading station, to a spherical or cylindrical bending of the panes made in the furnace section.
• Another means of transfer operating without grasping the windows operates by differential pressure.
• a plate adapted to the contour and possibly to the bending of the glass plates is used again counter-bearing, a vacuum being generated on one side either by suction of air by perforations made in this plate, or by suction of air by a slot-like skirt, around the windows.
• the windows can then be lifted and transferred using differential pressure.
• skirt is also suitable for lifting two or more stacked windows.
• a transfer means operating by differential pressure is described for example in US 3,778,244 or EP0652185.
• a particularly suitable skirt corresponds to Figure 1 of WO2006072721 showing two juxtaposed panes simultaneously sucked upwards by the skirt.
• suction cups heat resistant
• Another advantage of the device according to the invention and of the corresponding method lies in the fact that in addition to minimizing the energy losses due to the cooling of the transport molds, it is also possible to use smaller oven doors.
• the openings releasing the oven doors no longer need to be adapted for the passage of the complete transport molds with the carriages or corresponding frames.
• they need only a little more space than the height in vertical section -deposit- still flat panes or -decreating- (curved) panes. Thanks to the reduced openings, the energy losses are further reduced, especially since the furnace atmosphere is usually under a slight overpressure.
• the pair of windows is still at this moment maintained by the other grapples.
• the successive detachment of the grippers from two opposite sides is coordinated with the transfer movement so that, during the transfer, the pair of windows is already partially supported by the frame transport carriage.
• This embodiment is especially advantageous if the transport mold, in the transfer zone or deposit, is on an elevator but can of course also be realized in other configurations.
• the transfer device can however also deposit the window on the transport mold positioned below.
• Flat panes are provided in the oven, generally at least two superimposed panes (to be subsequently assembled in the same laminated glazing) and bulging panes are removed by gravity.
• This bending may correspond to the desired final shape or be only an intermediate stage of bending, the panes and pre-curved then being treated in an additional step to receive a larger complementary bending.
• the frame or skeleton on which the windows are deposited exceeds as little as possible edge edges of the windows.
• the periphery of the windows exceeds a little of said mold since the grapples should be able to remain a little below the edges of the panes until they are actually placed on the mold.
• the grapples actually support the windows by their edges.
• the periphery of the windows exceeds in all its perimeter by at least 2 mm of the transport mold on which they are deposited.
• the panes protrude less from the transport mold due to their curvature.
• a grapple transfer device for loading the windows and a skirt transfer device for unloading the windows are combined.
• the fact of using a skirt on unloading makes it possible to use a mold whose contour is very close to that of the windows as soon as it is loaded, it being understood that the still flat windows must still protrude a little from the mold at the time of loading.
• the windows and the transport mold that supports them are on an elevator.
• the support of the windows by the skirt can be realized after vertical movement down from the skirt to the windows still on their transport mold, or after vertical upward movement of the elevator towards the skirt, said elevator then performing, after the support of the windows by the skirt, a downward movement to end up in the lower section of the oven, as part of its loop cycle inside the oven.
• the skirt For the support of windows by the skirt, one can also have a combination of the lowering of the skirt to the windows and the rise of windows to the skirt with the elevator.
• the molds may be of the type trolleys comprising wheels, said trolleys moving on rails.
• the trolleys may also include a frame that can move on a bed of rollers.
• each elevator comprises on its surface a section for conveying the molds, such as a section of rails or a roll bed section. This conveying section is attached to the elevator and follows its vertical movement. The molds can therefore simply be placed on rails or rollers.
• Figures 1 and 2 show a simplified illustration and not the scale sectional views of devices according to the invention.
• the device according to the invention 1 is substantially composed of an oven section 2 with a loading station 3.
• the furnace section 2 comprises heating zones, bending and cooling in two superimposed planes in which transport molds 4 are moved gradually in cadence in the direction of the arrows T1 or T2.
• the transport molds 4 consist of a carriage-type carrying frame 5 with wheels 6 as well as a frame-shaped bent mold 7 resting on it and serving as a support proper for the panes 8.
• the lower of the two oven planes constitutes the cooling zone. Transfer of the transport molds 4 from the upper furnace plane to the lower furnace plane takes place by means of an elevator 9 and that of the lower furnace plane to the upper furnace plane takes place by means of another elevator 9 '.
• the transport molds 4 thus turn in the furnace section 2 on a closed loop band without leaving the device 1 or the furnace section 2 at any location.
• a conveying device F for conveying the windows from outside the furnace section 1 is shown in dotted lines. This can be here for example a roller conveyor.
• a breakthrough 10 which is normally closed by a furnace door 11.
• the breakthrough is relatively small, preferably in the form of a slot because respectively only a flat pane must pass through it by means of the transfer device made as flat as possible.
• the oven door 11 is only temporarily open for a transfer device 12 carrying the window 8 'taken by the device. conveying can enter the oven and come out after the deposit of the glass. This minimizes the overall thermal losses due to the breakthrough 10.
• the transfer device 12 thus takes flat panes 8 'on the conveying device F and transfers them to a transport mold 4' ready inside the furnace section 1. It should thus be understood that at least the mold transport 4 'is temporarily stopped so that a window 8' can be deposited on it with a sufficiently precise positioning.
• the transfer device 12 for the flat (still cold) glass panes 8 ' is then used to hold hook-shaped grippers 13 which can pivot about an axis. They block the windows during the vertical and horizontal movements of the transfer device 12 indicated by the arrows V and H. In this way, it is possible to transfer both individual panes or two or more panes superimposed in coincidence from outside the oven on the transport mold 4 '.
• the other transport molds can continue to advance for each loading and unloading operation.
• the actuating and propelling devices for the elevators 9 and 9 ' can quite be in the hot zone of the furnace section, so that this case also no opening in the furnace casing is necessary.
• the transfer device 12 leaves the oven to supply the following panes.
• the oven door 11 closes.
• the transport mold 4 ' continues to advance like the other transport molds 4 located in the upper part of the furnace section in the direction of the arrow T1.
• the flat first windows resting on the frame-shaped bent mold 7 are heated to a temperature at which the glass can be deformed under the influence of gravity.
• the windows thus adapt gradually to the contour of the bent mold 7.
• This rather simple embodiment of the transport molds or of the frame-shaped contact surfaces can also be used for another shaping if, in a manner known per se, adjustable curved molds with a variable geometry are used in a controlled manner, particularly with pivotable parts, for performing a bending operation in several stages and which, once the softening temperature is reached and after a first bending of the panes, are convertible into a second form in which the counter-arcuate panes are even more strongly distorted.
• the transport molds are lowered at the end of the upper plane of the furnace section 2 by means of the elevator 9 to the lower plane and continue to advance in the direction of the arrow T2 contrary to the T1 direction. In this phase of movement of the transport molds the bending operation is completed.
• the windows are now cooled in a controlled manner during the return of the transport molds in the T2 direction. This prevents any new undesirable deformation of the windows and facilitates their subsequent processing. It should be kept in mind that this planned cooling is much lighter than that experienced by a transport mold in traditional devices at the exit of the furnace section.
• This opening 12 ' is also normally closed by an oven door and is open only for removal of panes. It is even possible to close substantially the openings 12 and 12 'while the transfer device is in the oven section, and this by providing in the oven doors indentations that are just large enough to leave room horizontal drive bars 14 or equivalent means. These indentations can in turn be closed by second oven doors when the transfer device is outside the furnace section 2.
• each transport mold remains unloaded only during a single pulse step during the rotation of the series of transport molds.
• the bending process can therefore be carried out without the need for a transport mold 4 to leave the furnace section, whether for loading or unloading the windows.
• the windows could also be removed from the transport molds 4 at the elevator 9 and conveyed to another treatment outside the furnace section.
• the lower section indicated by the arrow T2 of the furnace section would naturally not be a cooling section but could be maintained at the same temperature as the upper section T1.
• FIG. 2 illustrates an embodiment according to which the panes, generally at least two superimposed panes, are bulging by gravity over a length of furnace only.
• the windows are loaded on the trolleys as was described for Figure 1 (right of the oven of the figure), but arrived at the other end of the oven, they are unloaded from their trolley by the skirt 20 which hold them against a convex shape thanks to a suction exerted on the periphery of the windows.
• the skirt is placed just above the elevator 9, so that when the windows are supported by the skirt, the elevator can lower the transport mold rid of its windows.
• This vacuum transport mold will then undertake the path T2 to return to the first elevator on the right in Figure 2, and be loaded again by one or more windows stacked.
• the support of the windows by the skirt 20 can be realized after vertical movement down from the skirt to the windows still on their transport mold, or after vertical upward movement of the elevator 9 towards the skirt, said elevator then performing , after the management of the windows by the skirt 20, a downward movement to end up in the lower section of the oven, as part of its loop cycle inside the oven.
• For the support of windows by the skirt one can also have a combination of the lowering of the skirt to the windows and the rise of windows to the skirt with the elevator.
• the upper section and the lower section of the furnace are preferably at substantially the same temperatures, so that the transport molds thus always remain at substantially the same temperature.
• a support not shown can pass (as for charging to the right of the oven) to recover the glass as the suction of the skirt is cut.
• This support can drive the windows into a cooling zone.
• This support can also be a mold intended to give the windows a larger bending. In particular, it may be a concave solid mold whose surface has orifices to exert a suction on the panes and continue their bending. Such a concave mold operating with suction has been described in particular in WO2006072721 (particularly its Figure 2).

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)

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• 2007
  • 2007-02-17 DE DE102007007974A patent/DE102007007974B4/de not_active Expired - Fee Related
  • 2007-11-29 EP EP07858755A patent/EP2091875A1/de not_active Withdrawn
  • 2007-11-29 WO PCT/FR2007/052422 patent/WO2008065312A1/fr not_active Ceased

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