JPH0455987B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method and apparatus for applying a solder coating to a metallized edge of a vitreous sheet. The invention particularly provides that the vitreous sheets are soldered to each other at their edges or that the vitreous sheets are spaced apart with intervening metal spacer members soldered to the metallized and solder coated edges of the sheets. The present invention has found application in the field of multilayer glass panels held in a vacuum. Such soldering can be carried out using only solder previously applied to the sheet edges and/or the spacer elements, if present, or additional solder can be applied. Various proposals have been made for applying solder to the edges of such metal-coated sheets. Initially, such solder coatings were formed by hand by melting solder in situ. This is hard work, expensive, and
It was a waste of time. Various efforts have therefore been made to mechanize this work. One such proposal is described in British Patent No. 1,418,827 for Gravelbel Mechanivre. This document specifically proposes applying the solder in molten form (in the form of droplets) and then spreading out the droplets with a heating shoe to form a more or less uniform coating. This specification also describes jetting molten solder onto narrow edged strips, allowing the solder to spread under surface tension effects, again providing a generally uniform coverage. It is an object of the invention to provide an alternative method for applying solder to the edges of metallized sheets, which allows a more uniform coating quality to be achieved. According to the present invention, there is provided a method for applying a coating of solder to a metallized edge of a vitreous sheet, the method comprising dispensing an excess of molten solder along the edge of the sheet, and melting the supplied solder. During the process, a doctor knife is used to continuously direct the excess molten solder towards and onto the edges of the sheet. The present invention makes it possible to apply a high quality uniform coating of solder to the edges of metallized sheets. The invention also makes it possible to apply a desired thickness, particularly thick solder coating, to the edges of the metallized sheet. The method of the invention can be easily mechanized.
When making multilayer glass panels, it is always necessary to convey the vitreous sheet from one processing station to the next, so that as the sheet moves along the conveyor, the It is particularly advantageous to mount the solder supply device and the doctor knife on the conveyor in such a position that one edge is automatically coated with solder. Of course, when soldering the edges of rectangular sheets, which is the most common, a second solder supply device and a doctor knife can be placed simultaneously on opposite edges of the sheet for soldering. Although it is of course within the scope of the invention to simply solder coat one metallized edge area of a vitreous sheet, it is also within the scope of the invention to metallize and solder coat an edge that extends around the entire periphery of the sheet. is a more common practical requirement. Different edges of the sheet can be metallized and solder coated in separate steps, and it is not necessary to complete the entire metallization operation before applying solder to the sheet. One preferred manufacturing schedule for actually processing rectangular sheets involves conveying the sheets sequentially through four processing stations, the first of which metal coats one edge and then coats with solder. After translation of the sheet, a second station metallizes the opposite edge and then coats this edge with solder. Then the conveyor
The sheet is then turned 90 degrees and transported to a third station where one of the two remaining edges is metallized and coated with solder, then transported to a fourth station where the final sheet edge is metallized. grant,
Cover with solder. It will be appreciated that the sheet can be alternately conveyed twice into each of the two stations to metallize and solder coat its four edges. It will also be appreciated that the solder coating formed in accordance with the present invention need not be co-spatial and co-temporal with the metallization layer to which it is deposited. In fact, such simultaneous application is undesirable, at least as far as the coatings applied at the first and second processing stations are concerned when working according to the manufacturing schedule described above.
In this case, it is preferred to leave a strip of each metallization layer uncovered so that a subsequently applied metallization strip can be directly attached to the first applied strip at the corner of the panel. The molten solder may be applied to the edge of the metal-coated sheet in the form of droplets or by spraying. However, it is preferable to supply it as a jet from a nozzle, since the features combined with the relative movement of the nozzle and the edges ensure the deposition of a continuous strip of molten solder, eliminating the need for thickness adjustment with a doctor knife. This is because it also enables efficient use of the solder that would otherwise be consumed. Such a solder delivery nozzle is preferably placed above the sheet in order to discharge the solder in a direction with a horizontal component towards the edge of the sheet. This facilitates directing excess molten solder onto the edge of the sheet by the doctor knife. The best results are obtained when the solder delivery nozzle is placed at an angle substantially perpendicular to the edge of the sheet in the area where the solder jet impinges, because for a constant solder jet velocity, the edge of the sheet This is because the horizontal velocity component of the solder toward the direction is maximum. In the most preferred embodiment of the invention, the sheet is substantially horizontal and the solder delivery nozzle is inclined to the horizontal at an angle of 30 to 60 degrees. In the apparatus for carrying out the method of the invention, the doctor knife is a gas knife. It has also been found that by using a gas knife, it is easier to control the thickness of the solder coating applied, and that the gas knife provides improved surface finish and uniformity to solder coatings, particularly thick coatings. It has also been found that the use of a gas knife allows for a good quality bond between the vitreous sheet and the component to be soldered to its edge, since there is less risk of damaging the edge. The gas knife blows out a stream of gas to impinge on the edge of the sheet, and the impingement zone is formed into an elongated band, the direction of which is at an acute angle with respect to the edge of the sheet, and this acute angle Preferably, a zone for supplying molten solder is included in the plane of the enclosed sheet. Also, acute angles
70-90° is preferred. The apparatus for carrying out the method of the invention comprises: a support defining a predetermined trajectory for said sheet;
Apparatus for supplying excess molten solder to the edge of a sheet carried by said support; apparatus for effecting relative movement between said sheet carried by said support and such solder supply apparatus; and Associated with the solder feeder is a gas knife positioned to direct excess molten solder toward and onto the edges of the sheet. This is a simple and convenient device for carrying out the method of the invention. Advantageously, the support is a conveyor for conveying the sheet continuously along a predetermined path constituting the trajectory. It has been found that it is easier to move the sheet relative to the solder feeder than vice versa. Preferably, the device according to the invention has one or more of the following optional features. The solder supply device has a nozzle for dispensing a jet of solder; the nozzle is arranged to eject the solder in a direction having a horizontal component toward the end of the sheet trajectory (referring to the sheet in a predetermined position); the support body is arranged to horizontally support the sheet, and the nozzle is inclined at an angle of 30 to 60 degrees with respect to the horizontal; the doctor knife is a gas knife; is arranged to direct a gas flow against the edge of the sheet trajectory on an elongated band making an acute angle with the edge of the sheet trajectory, and the solder is in the plane of the sheet trajectory (i.e. the plane of the support) enclosed by this acute angle. includes an orthogonal projection of the delivery end of the feeding device; said acute angle is between 70 and 90 degrees; Include equipment for supplying gas. A preferred example of the device according to the present invention will be described with reference to the drawings. In the drawing, the solder supply device 1 has a cylindrical structure 2 with a bore 3 terminating in a nozzle 4 for delivering a jet of solder onto the metallized edge 5 of a vitreous sheet 6. The support for the sheet 6 is not shown. Actually seat 6
is conveniently supported on a conveyor, for example a conventional roller conveyor. An edge guide device (not shown) is preferably provided, which may take the form of a guide roller for defining the trajectory for the edge 7 of the sheet. On the other hand, when the support is arranged to hold the sheet 6 fixedly, a device is provided for moving the solder supply device 1 and the associated doctor knife 8 along the edge 5 of the sheet. The doctor knife 8 is a gas knife and has a block 9 adapted to form a slot 10 communicating with an air supply tube 11 attached to the block 9 by an end fitting 12. Solder supply boring 3 of cylindrical structure 2
is a horizontal plane perpendicular to the trajectory of the edge 7 of the sheet at an angle of 45° to the horizontal sheet trajectory so that the jet of solder delivered by the nozzle 4 has a horizontal component of movement towards the edge 7 of the sheet. to place it on the trajectory of sheet 6. The slot 10 of the gas knife 8 has an elongated opening arranged to direct a perpendicularly descending gas flow forming an elongated zone of impingement area at the edge 5 of the sheet 6. As shown in FIG. 2, the long axis of the opening of slot 10 is disposed at 6 DEG to the right angle to edge 7 of sheet 6, thus forming an 84 DEG acute angle therewith. Within this acute angle are the supply zone of molten solder and the nozzle 4 at the delivery end of the solder supply device 1.
contains the orthogonal projection of the sheet trajectory of . The cylindrical structure 2 of the solder feeder may incorporate a heating device to keep the solder flowing through the bore 3 at a suitable temperature and/or it may be thermally insulated. In use, solder may be fed into the bore 3 by gravity from a heated crucible (not shown), and excess solder flowing over the edges of the sheet is preferably collected in an overflow pan (not shown). This overflow pan can also be heated to keep the solder molten, and such excess solder can be recycled to the heated crucible for reuse. In a particular embodiment of the device described above, the boring 3 has a length of 12-15 cm and the nozzle 4 has a length of 3.5 cm.
It has an inner diameter of mm. The lower end of the mouth of nozzle 4 is 10~
It is placed 4 mm above the top surface of a sheet 6 with a metallized edge 5 of 12 mm width and 5 to 15 μm thickness. In order to cover the entire width of the metalized edge 5 with solder, the nozzle 4 is centered on its orifice on the sheet approximately 13 mm inside the edge of the sheet, i.e. approximately 1-3 mm from the inner border of the metalized edge 5. is arranged so that it has an orthogonal projection of . As previously mentioned, it is sometimes preferable not to coat the entire metallization edge with solder so as to provide a key for subsequent metallization coatings. In such cases the nozzle is placed near the edge of the sheet, leaving an uncoated metallized strip (e.g. 2-3 mm or more wide).
The solder is fed into the nozzle at a head height of about 40 cm to provide a pressure of about 400 g/cm ² , thus ejecting the solder jet at a rate of 8.2 m ³ /sec. The optimum thickness of the solder coating to be applied depends largely on the subsequent assembly operation. For example, considering a double glazing unit in which a metal spacer is soldered between the metallized and solder coated edges of a pair of vitreous sheets, the soldering of the spacer to the sheet may be accomplished with or without additional solder. can.
For example, flat lead-based spacer strips can be soldered along the edges between a pair of sheets with beads of solder applied in a step subsequent to the coating step.
In this case, the solder coating applied according to the invention can be considered simply as a tinned coating;
Only a thickness of 20-25 μm is required. According to another manufacturing technique, a solder-coated flanged spacer element is soldered with its flange in face-to-face contact with the solder-coated metallized edge of a pair of sheets, which allows assembly without additional soldering. This is done by gripping the three-dimensional object and heating it to melt the solder coating applied in advance. In this case it is desirable for the solder coating on the sheet edges to be thicker, for example 100-200 μm thick. In plant production, the vitreous sheet can be conveyed along the production line at a speed of 22 m/min, this speed depending, for example, on the metallization and cleaning to be carried out. Thickness 200μm, width 12
The application of a solder coating of mm uses 0.88 m ³ /s of molten solder, i.e. about 11% of the feed rate (at a rate of 8.2 m ³ /s), the remaining solder is recirculated by a gas doctor. A knife is directed over the edge of the sheet. Such solder coating thicknesses are easily achieved by using a gas knife with a suitably sized slot opening, a suitable spacing from the sheet edge, and a suitable gas flow rate and pressure. By way of example, various parameters associated with two such gas knives are shown below.

[Table] In fact, when using such a gas knife, the thickness of the solder coating can be regulated simply by adjusting the gas supply pressure. To achieve a coating thickness of 20-25 μm, a gas overpressure of several kg/cm ² is required.

[Brief explanation of the drawing]

Figures 1, 2 and 3 respectively show the end faces of the solder supply device and the combined doctor knife;
FIG. 2 is a plan view and a side view. 1 is a solder supply device, 2 is a cylindrical structure, 3 is a boring, 4 is a nozzle, 5 is an edge of a vitreous sheet, 6 is a vitreous sheet, 7 is an edge of the sheet,
8 is a doctor knife, 9 is a block, 10 is a slot, 11 is a supply pipe, and 12 is an end fitting.

Claims (1)

[Scope of Claims] 1. In a method of applying molten solder to the edge of a glass sheet with a metal coating to provide a solder coating, an excess of molten solder is supplied along the edge of the sheet, and the thus supplied solder is applied. A method characterized in that during melting the solder is treated with a doctor knife to continuously direct the excess amount of molten solder onto and onto the edges of the sheet. 2. A method according to claim 1, wherein the solder is supplied as a jet from a nozzle. 3. A method as claimed in claim 1 or claim 2, in which such a solder delivery nozzle is placed on the sheet for discharging the solder in a direction having a horizontal component towards the edge of the sheet. 4. The method of claim 3, wherein the solder delivery nozzle is angled substantially perpendicular to the edge of the sheet in the area where the jet of solder impinges. 5. A method according to claim 3 or claim 4, wherein said sheet is substantially horizontal and said solder delivery nozzle is inclined with respect to the horizontal at an angle of 30 to 60 degrees. 6. The method according to any one of claims 1 to 5, wherein the doctor knife is a gas knife. 7. The gas knife includes a zone that injects a gas stream to impinge on the edge of the sheet in an elongated zone that makes an acute angle with the edge of the sheet and supplies molten solder within the plane of the sheet defined by the acute angle. The method described in scope item 6. 8. The method of claim 7, wherein said acute angle is between 70 and 90 degrees. 9. A support defining a predetermined trajectory for the vitreous sheet, an apparatus for applying molten solder to the edges of the sheet carried by the support, and said sheet carried by the support and such solder. An apparatus for applying a coating of solder to a metallized edge of a vitreous sheet comprising a device for effecting relative movement between soldering devices, said soldering device displacing an excess amount of molten solder along said sheet edge; a vitreous sheet of metal, characterized in that it comprises a gas knife associated with the solder supply device and arranged to direct an excess amount of molten solder towards and onto the edges of the sheet. Transfer to apply solder coating to the coating edge. 10. The apparatus of claim 9, wherein said support is a conveyor for conveying said sheets continuously along a predetermined path defining said trajectory. 11. The apparatus of claim 9 or 10, wherein the solder supply device includes a nozzle for delivering a jet of solder. 12. The apparatus of claim 11, wherein the nozzle is on the sheet trajectory for ejecting solder in a direction having a horizontal component towards the end of the sheet trajectory. 13. The apparatus of claim 12, wherein the solder delivery nozzle is angled substantially perpendicular to the edge of the sheet in the area where the jet of solder impinges. 14. Claims 11 to 14, wherein the support is arranged to horizontally support the sheet, and the nozzle is inclined at an angle of 30 to 60 degrees with respect to the horizontal.
Apparatus according to any one of clauses 13. 15 Said gas knife is arranged to inject a gas stream impinging on said support in an elongated zone at the edge of the sheet trajectory, forming an acute angle with the edge of the sheet trajectory, the surface of said support defined by said acute angle 10. The apparatus of claim 9, including an orthogonal projection of the delivery end of said solder feeder onto said support. 16. A device according to claim 9 or claim 15, wherein the device for making a gas knife comprises a block with a slot orifice and a device for supplying gas under pressure to the block for evacuation through such a slot. Device.