SI8811912A - Cooling plates of hardening device - Google Patents

Abstract

Cooling plates according to the invention of the tempering apparatus with they are characterized by the fact that the upper layer (8) s thermal resistance between 0,25.10'3 and 10'2 m2 KW'1 from fine metal and carbon threads, interwoven, woven, knitted, or knitted, or stitched also interwoven, knitted, interwoven or sintered.

Description

SAINT-GOBAIN WINDOWS

Hardening device cooling plate

The field of technology

The invention falls within the field of glassware production. According to the international patent classification, the subject matter of the invention is classified in classes C 03B 27/00, C 03B 27/04, C 03B 23/03,

C 03B 40/00.

A technical problem

In view of the drawbacks of the solutions known so far, the technical problem is how to perform the tempering of the tempering device, possibly accompanied by the bombardment of the glass pane, so that the cooling plates have the desired thermal conductivity and are controlled by the glass pane. plate chemically inert.

The present invention seeks to address the glass-quenching refrigeration plates according to the touch process by proposing materials intended to cover the refrigeration plates of the touch-screen smelter.

It is important that these proposed materials do not have the disadvantages of previously tested materials.

They should also exhibit chemical inertia with respect to glass and its possible coatings (especially enamel), not damage the glass and / or its coatings, and have a flatness that guarantees the optical quality of the glass. They should also be capable of being deformed to accommodate complex shapes, in particular unexplained, that can be given to glass or already has glass. In order to allow tempering to permit the use of automotive windscreens so manufactured (in view of United Nations Regulation No 43, which deals with the acceptance of uniform type-approval conditions and the reciprocal recognition of the type-approval of motor vehicle components and components), thermal resistance, and in order to be industrially usable, they should have good mechanical resistance and durability, permitting a considerable number of thermal cycles at about 150 to 65 ° C in a short time (several hundred cycles in about 10 seconds). ____

The state of the art

From Japanese patent file no. 39-1029 it is known that a material having the role of a mechanical and thermal buffer is inserted between the glass and the cooling plate of the tempering device by touch. Proposed materials e.g. cloth ^ impregnated with silicone oil or lubricant, and the glass cloth does not give satisfactory results because they chemically react with glass (silicates), or are too brittle and therefore unsuitable for industrial use. Like other tampon material, fine and flexible metal foil is also suggested, e.g. of lead. Apart from the maladaptation of the thermal properties of such a metal film for toughening glass, it can also be cited as a possible problem to use such metal film on cooling plates which have complex, indivisible forms.

In addition, JP 39-1029, according to the state of the art, for touch-toughening of glass, mentions a non-compelling attempt to use strands of metallic filaments, making these metallic strands difficult to use and causing damage to the glass surface.

Description of a solution to a technical problem with an example implementation

The cooling plates according to the invention of the touch-quenching device are characterized in that the upper layer is thermally

-3 -2 -1 Resistance between 0,25.10 and 10 m ² KW of fine metal and carbon threads, interwoven, woven, knitted, weaved or stranded, whether or not knitted, knitted, knitted or sintered.

The invention will now be described in more detail with reference to the accompanying drawings, which are:

Fig. 1 is a schematic diagram of a toughening and possibly bombarding glass panel according to the touch procedure; FIG. 2 is a schematic diagram of a tampon structure inserted between the cooling plate of the toughening device and the glass.

FIG. 1 gives a general schematic of a toughening and eventual bombardment of glass panes by the touch procedure. Such a device essentially comprises a glass pan furnace 1 which is to be treated at a temperature in excess of the glass transformation temperature, or at a temperature of the order of 600 to 65 ° C, a tempering spot 2 and possibly a simultaneous bombardment having essentially two cooling panels 3 and 4 opposite each other, which are movable relative to each other so that they can be pressed against the glass panes V at a certain point due to quenching and eventual bombardment and can be moved away from each other at another moment to allow the removal of the glass pane that has been treated and the introduction of the next glass pane to be treated and also means 6 for supporting and transporting the glass pane from the furnace 1 to site 2 for tempering and possibly simultaneous bombardment. The quenching site 2 and possibly simultaneous bombardment preferably follow the secondary cooling site 7 in which the glass panels, the stresses of which have been frozen in contact with the cooling plates 3 and 4, end their cooling, thus releasing the plates 3 and 4 for quenching and possibly bombing other glass panels.

The glass pan support and transport means 6 are a roller conveyor and / or gas cushion, or a top conveyor by means of a vacuum which is movable on rails not represented or by some other equivalent system.

The surfaces of the cooling plates 3 and 4, which are intended to be pressed against the glass panes, are covered with materials 5 which are both a thermal and a mechanical tampon.

Preferably, they are cooled e.g. by circulating water or other agent inside them to prevent them from overheating and deforming when used at an accelerated pace.

Said plates are also designed to avoid deformation under the influence of heat, and in particular of the considerable thermal gradient existing between the surface of the cooling plates 3 and 4 and their cooled interior, from a material which is slightly deformed under heat. Thus, e.g. graphite is suitable as a material where the dependence of the linear expansion coefficient on thermal conductivity is weak.

This tampon 5, which covers the cooling plates 3 and 4, is made of at least one plate 8 (see FIG. 2) which is in direct contact with the glass and is made of a porous material having thermal resistance, i.e. thickness dependence of this material and its thermal conductivity, between about 0.25.10 ^J and 2.5.10 m ² KW, when it comes to the hardening of glass panels whose thickness varies between 1 and 10 mm.

Such material permits the reduction of heat flow between the glass and the cooling plates 3 and 4 and permits tempering in accordance with regulation no. 43 of the United Nations Understanding on the Acceptance of Uniform Conditions of Approval and the Reciprocal Recognition of the Approval of Equipment and Components of Motor Vehicles. According to this regulation, automotive glass must contain such hardening stresses that the number of fragments, when struck at the points specified in this regulation, is entirely in the form of a square of 5 cm x 5 cm not less than 40 and greater than 350 (the number is increased to 400 for glass of 3.5 mm thickness and down), no fragments having more than 3 cm ^{2 of the} surface except possibly in a band 2 cm wide at the perimeter of the glass and at a distance of 7 3 cm around the point of impact and no a fragment that would be longer than 7.5 cm in length.

Within the proposed thermal resistance interval, the desired thermal resistance may be adjusted depending on the degree of toughening required, the resistivity having to be greater than the finer fragmentation desired, or it may also be adjusted depending on the thickness of the glass to be tempered. , where this thermal resistance must decrease as the thickness of the glass decreases in order to maintain the same fragmentation.

If materials with a resistivity, considering the thickness of the glass to be treated, are accepted for touch quenching, are relatively low or otherwise relatively high, although within the range of proposed resistances, glass can also be obtained if necessary panels that do not meet regulation no. 43 United Nations and has higher levels of tempering (finer fragmentation than required by regulation 43) or, conversely, weaker levels of tempering (greater fragmentation than required by regulation 43). Such glass panes, however, are not usable as simple tempered glass for cars, but can be used e.g. in construction or as components in laminated glass intended for cars, aircraft or other.

Suitable thermal resistance may be obtained from porous material, e.g. assembled with an ordered or unordered thread assembly. The threads can be of different nature (carbon, metal ...), but in order to provide this tampon to be inserted between the glass and the cooling panels 3 and 4, at least some of the threads are metallic

In order to simultaneously give the buffer material the ability to collect a certain amount of air inside it, which can give it the desired thermal resistance, as well as the flatness of the surface without the risk of causing damage to the glass, neither metal nor small ones are used. diameter, diameter as small as possible, certainly smaller than 50 ^ * »- and preferably smaller than

The fineness of the filaments and the porosity of the material allow this material to accumulate heat and to be completely insulator despite the inherent thermal conductivity of the metal filaments.

The metal composition does not fully or partially guarantee these materials the durability and improved mechanical properties of the intended use. These threads are assembled into strands whose or

- 8 at least some of which are then woven, knitted, braided or sintered to form the desired material. According to the variants, the threads are directly sintered, woven, knitted, interwoven without being pre-assembled into strands. The aggregation described below further increases the porosity of the material and further improves the material's ability to deform and adapt to cooling plates of various shapes. Various specimens of materials having a predefined thermal resistance have been successfully tested for tempering the glass panes and possibly for simultaneously bombarding them, with the cooling plates having the desired shape of glass panes in case of simultaneous bombardment.

EXAMPLE 1

Fabric with strands of woven carbon threads is obtained from threads 12 to 14 in diameter.

- -3 -1 is 0.1 mm. The thermal resistance is 10 m ² KW

It is used for quenching and simultaneously bombarding glass panels of 3 or 4 mm thickness, which meet the requirements of regulation no. 43 United Nations.

The thermal properties of the fabric are satisfactory and its mechanical behavior does not allow for industrial use.

EXAMPLE 2

The 0.14 mm thick fabric consists of 12 to 14 diameter stainless steel fibers that are sintered.

in -3 -1

The thermal resistance is 10 m ² KW

It has been successfully tested for tempering and simultaneous bombing of 3 mm thick glass panes that are sufficient

- 9 regulation no. 43 United Nations.

EXAMPLE 3

The 0.14 mm thick fabric is obtained from strands of woven strands of stainless steel 12 to 14 / κ * ζ in diameter.

-3 -1

The thermal resistance is 10 m ² KW

It has been successfully used for tempering and simultaneously bombarding glass panes with a thickness of 3 nuns, which complies with regulation no. 43 United Nations.

EXAMPLE 4

The fabric was obtained from strands comprising two types of stainless steel threads. The thermal resistance is 1.5.10 "^ m ² KW ^-1 .

It has been successfully tested for the quenching and simultaneous bombardment of 4 mm thick glass panes, which complies with regulation no. 43 United Nations.

EXAMPLE 5

0.42 mm thick fabric is obtained from -3 -1 threads of Inconel. The thermal resistance is 2.1 .10 m ² KW

It has been tested for quenching and simultaneously bombing 3 or 4 mm thick glass panes. The quenching rate obtained does not comply with regulation no. 43, fragmentation is too weak. These 3 or 4 mm thick windows have a low tempered level and cannot be used as a simple glass in a car. To be used in a car, they must be integrated into laminated glass.

It is this fabric that allows hardening under the conditions of regulation no. 43 for glass panels 6 or 8 frames thick. Such fragmentation can be obtained on glasses 6 or 8 mm thick by changing the pressure of the cooling plates on the glass upon quenching, ie by more or less pushing the fabric, making the fabric suppression weaker in order to harden with the same degree of less thick glass.

EXAMPLE 6

The 0.08 mm thick fabric is made from uniform strands of bronze with a thickness of 0.04 mm. The thermal resistance is 0.25.10 ^-3 m ² KW ^-1 .

It has been successfully tested for tempering and simultaneous bombardment of 1.6 mm thick glass panes, which complies with regulation no. 43. It also enabled hyper hardening, that is to say, hardening by fragmentation in excess of the fragmentation determined by regulation no. 43, of glass having a thickness of 3 or 4 mm.

EXAMPLE 7

The 0.08 mm thick fabric is woven based on uniform 0.04 mm stainless steel threads. The thermal resistance is 0.25.10 ^-3 m ² KW ^-1 .

It has been tested with success for hardening 1.6 mm thick glass, which complies with regulation no. 43.

The hyper hardening is suitable for glass panels 3 and 4 mm thick.

EXAMPLE 8

The 0.45 mm thick fabric is obtained by weaving strands of stainless steel thread. It's thermal resistance

2.1.10 ^-3 m ² KW ^-1 .

Hardening was carried out according to regulation no. 43 on glasses 6, 8, 10 mm thick. Reinforcement (quenching by fragmentation below that defined by regulation 43) of glass panels 3 and 4 mm thick.

As stated in the examples, different thermal resistances can be obtained from the same fabric by varying the compression of this fabric upon quenching, which allows modifying the quenching without modifying the material.

Local modifications of the level of global toughening of glass panes can also be achieved by placing them at the desired location of a section of fabric that has thermal characteristics other than fabric that is installed everywhere else on the cooling plates.

In all the above cases except Case 1, the durability of the fabric is such that industrial use does not present a problem. Fabric made from two types of strands or threads, one of which is metal, the other of which is carbon, also satisfies.

Preferably, for the use of tempering and possibly touch bombardment, a layer of material with a thermal resistance of between 0.25 and 2.5 m ² KW ^-1 is connected to the lower layer 9 (see FIG. 2) of another material having in particular the role of a mechanical tampon.

Indeed, the limitations of thermal resistance, such as the constraints on the flatness, fineness of the threads placed on the material for layer 8, make it difficult for the mechanical tampon to be filled frequently and integrally and optimally by said layer 8.

Therefore, it is desirable to install an additional lower layer 9.

As can be seen from FIG. 2, therefore, the cooling plates 3 and 4 receive a cover 5 on their surface, intended to come into contact with the glass panels which need to be germinated and possibly bombarded, this coating 5 preferably consisting of a layer 8 which plays in essence the role of the thermal pad previously described and from the bottom layer 9, which plays essentially the role of the mechanical pad, which will be described below.

Therefore, we generally have two layers one above the other to form tampon 5, and it is very easy to select for each of these layers suitable materials to fulfill in an optimal way the role of one mechanical tampon and the other heat tampon.

The material for the lower layer 9, which essentially plays the role of a mechanical tampon, must have sufficient elasticity and compressibility to compensate for imperfections in machining and in the installation of cooling plates 3 and 4. This elasticity, however, must not be accompanied by excessive softness, for in case of improper breakage of glass, the material would be marked and would have a fatal effect on the optical quality of the glass panes, which would be tempered afterwards. Of course, it also has the ability to withstand heat, chemical inertia with respect to glass and deformability.

Therefore, materials with a thickness change of between 0.01 and 0.5 mm will be appropriate for pressures between 0.1 and 10 bars. In the present cases, where the tolerances of the machining process from the cooling plates are in the order of 0.05 to 0.1 mm and where the uncertainties in the regulation range from 0.5 to 0.10 mm, the materials whose thickness changes are preferably considered to be suitable ranks between 0.05 mm and 0.20 mm for pressures varying from 0.10 to 10 bar. In other words, materials having a Young's modulus of between 0.1 MPa and 100 MPa, and most often, to fit the present case, will correspond to materials whose Young's modulus is between 0.50 and 20 MPa.

Otherwise, this lower layer must not obscure the thermal characteristics of the material which essentially plays the role of the heat buffer, namely the material for layer 8. In particular, this lower layer should not represent a significant additional thermal resistance contrary to the heat flow from the cooling plates.

Thus, the lower layer 9 must have a thermal conductivity that is significant in a direction perpendicular to that of the glass panes to be germinated and that of the cooling plates 3 and 4. This thermal conductivity must be at least an order of magnitude 2 Wm and preferably at least 4, leading to a thermal resistance substantially less than that for the material acting as a heat pad (at least twice as weak and preferably at least 10 times weaker).

Preferably, the thermal conductivity is in the longitudinal direction, i.e. in the direction tangent to the cooling

- 14 panels important to allow heat dissipated to be removed from the glass.

It therefore corresponds to the material sold under the designation ΡΑΡΥΕΧ and manufactured by Carbone Lorraine '. *.

This material is made of expanded graphite and is sold in films and has an anisotropy of structure such that the conductivity in the plane of the film, that is, in the tangent direction on the cooling plate, is significant, greater than the conductivity in the direction perpendicular to at least 10 times.

-1 -1

Conductances of 4 to 160 Um K in the tested sample are thus appropriate. This material is used in thicknesses from 0.20 mm to 4 mm and preferably from 0.50 to 2.50 mm.

Layer 8 and bottom layer 9 can only be folded and secured in panels 3 and 4 or preferably glued to avoid air spaces.

Tempered glass having at least one zone locally at different levels of tempering may also be obtained by providing a bottom layer having at least one area locally with properties different from those for the remaining surface.

Claims (8)

1. Touch-plate cooling plates, characterized in that the upper layer (8) with a thermal resistance of oo 1 is between 0.25.10 ^-3 and 10 "m ² KW ~ made of fine metal and carbon threads, interwoven, woven, knitted, braided or stranded, whether or not braided, woven, knitted, knitted or sintered. Panels according to claim 1, characterized in that the threads have a diameter of less than 15 µm. 3. Plates according to any of the preceding claims, in * -3, characterized in that they have a thermal resistance of between 0,25.10 and 2,5.10 ^-3 m ² KW ^-1 . Panels according to claim 3, characterized in that their thermal resistance is reduced to. the desired value during touch-quenching by adjusting the pressure at the pressure of the cooling plates against the glass panes. Panels according to claim 1, characterized in that the layer (8) is glued to the lower layer (9) having a thermal conductivity of at least i i - 1 “1 in the direction perpendicular to the cooling plate. 2 W m ^- K and preferably about 4 W m K Panels according to claim 5, characterized in that the upper layer (8) of the anisotropic structure is at least 10 times increased in thermal conductivity in a direction tangent to the cooling plate. Panels according to claim 5 or 6, characterized in that the bottom layer (9) of expanded graphite is 0.20 to 4 mm thick and preferably 0.50 to 2.5 mm thick. Panels according to any one of claims 1 to 7, characterized in that they are made of a material having a low coefficient of linear expansion and thermal conductivity, in particular graphite.