FR2482948A1 - Glass tempering plant - with heating and quenching stations using smooth surfaced belt and roller to move glass sheets - Google Patents

Abstract

Glass tempering plant comprises a heating furnace with an endless conveyor belt supported on rollers. One set of rollers are of ceramic and are provided with axial journal bearings at their ends. A second set of rollers is provided supporting the belt and arranged to move independently from the first set such that the glass sheets being heat treated and the belt can be subjected to oscillatory movement at certain locations in the furnace by making the two sets of rollers move alternately according to a predetermined programme of alternations, prior to discharge from the furnace to the cooling section. The roller bearings are at the ends of the rolls and can be removed and replaced horizontally. The belt can be made away from the machine so that the supporting surface is completely smooth and does not have asperities due to the joint which cause deformation of the glass sheet supported at the joint. Hence the sheet in 30 or 40 waste of prior art, is eliminated. The oscillation in the furnace allows the length of the hot zone to be reduced, while now allowing the glass to move across the metal sheet.

Description

The invention relates to glass tempering installations, as well as to new elements and components of these installations, and finally to the methods of construction and operation of these installations.

 The invention provides for this purpose a glass tempering installation which comprises an oven comprising an upper part and a lower part which form a heating chamber which extends horizontally. The installation further comprises several heating means arranged in the upper part. The installation includes a first set of sashes to support the upper part, as well as a second set of frames to support the lower part. Several first adjustable support rollers are arranged on a top surface of the second set of casings. An endless flexible belt is supported, at least partially, by the sets of support rollers. Several first elongated ceramic rollers are distributed along the heating chamber. The first elongated rollers are provided with non-metallic cylindrical trunnions retained by friction in openings provided in each end of the elongated rollers and coaxially with the axis thereof. Adjustable guide members are traversed by at least one elongated opening intended to receive one of the cylindrical journals retained in one of the elongated rollers.

A loading section includes a third set of chases connected to the second set of chassis. Several of the first adjustable support rollers are arranged on a su perkeure surface of the third set of chassis. The belt is supported by the first adjustable support rollers. The second elongated rollers are driven by the endless belt. The second elongate rollers have at each of their ends an axis intended to be housed in an opening provided for this purpose in the corresponding adjustable guide member. A cooling unit comprises several adjustable support rollers intended to support part of the belt. Several of the second elongated rollers are driven by the belt. Drive means are provided for the belt, and include control means which allow the belt to rotate alternately the first and second elongated rollers in a first direction, then in the opposite direction, with an amplitude of rotation adjustable electronically. , and at an adjustable speed of rotation, and to also produce a unidirectional and prolonged rotation of the first and second support rollers at an adjustable speed after a predetermined number of alternating rotations in advance, so that a glass plate placed on the second rollers elongated in this loading section is transferred to a heating chamber, subjected to adjustable oscillations in several places inside the oven, transferred to the cooling unit to be sounded at other oscillations, and finally directed to the unloading section,
Reference will now be made to the accompanying drawings for a more detailed description of the invention.
FIGURE 1 is a side elevational view of a glass tempering installation according to a first embodiment;
FIGURA 2 is a plan view and partial section of the same installation, the section being taken along line 2-2 of Figure 1;
FIGURE 3 is a side elevational view showing a set of support rollers according to a first embodiment;
FIGURE 4 is a section taken along line 4-4 of the
Figure 3;
FIGURE 5 is an exploded view of a set of support rollers according to a first embodiment;
FIGURE 6 shows the assembly of Figure 5 after assembly of its constituent elements;
FIGURE 7 is an end view of a belt support roller, made looking in the direction of the arrows 7-7 of Figure 6;
FIGURE S is a side elevational view of a roller shoe according to a first embodiment;
FIGURE 9 is an end view made looking in the direction of arrows 9-9 of Figure 8;
FIGURE 10 is a side elevational view of a set of support rollers according to a first embodiment, intended to be used in unheated sections of the installation;
FIGURE 11 is a view of the set of support rollers, made looking in the direction of the arrows 11-11 of Figure 10:
FIGURE 12 is a perspective view of a trunnion pad for a roller, according to a first embodiment;
FIGURE 13 is an end view and elevation of the trunnion pad of Figure 12;
FIGURE 14 is a detail view in side elevation, showing the mounting of a rubber washer on a roller according to a first embodiment;
FIGURE 15 is an end elevational view, in partial section, of the rubber washer and roller assembly of Figure 14;
FIGURE 16 is a sectional view, taken along line 16-16 of Figure 1, showing a first embodiment of the cooling unit;
FIGURE 17 shows in sectional elevation along line 17-17 of Figure 16 the same cooling unit;
FIGURE 18 is a sectional view of a first embodiment of an oven section, in which the entire upper portion of the oven is raised to provide access to the heating chamber;
FIGURE 19 is a sectional view of a second embodiment of a furnace section, where the upper part is in a fixed position, while side wall elements are movable to allow access to the chamber heater;
FIGURE 20 is a sectional view of a third embodiment of an oven section, showing the guide means provided for a movable upper part of the oven;
FIGURE 21 is a side elevational view in partial section, showing an unloading section of an installation according to a first embodiment;
FIGURE 22 is a side elevational view in partial section showing a loading section of an installation according to a first embodiment, and
FIGURE 23 is a sectional view relating to a fourth embodiment of an upper section of the oven, in which the upper part and the side wall parts are movable independently of each other to allow variable spacing between the heating means and the glass being processed.

 If we refer first to Figure 1, we see that a glass tempering installation comprising the new features of the invention comprises a loading section 1, modular oven frames 2, sections respectively upper 3 and lower 4 of the furnace, a cooling section 5 and an unloading section 6.

A motor means 7 rotates a shaft 8 supported by pa-
ties-supports 10 so as to turn in turn either an arm of
double crank 9a (Figure 18), i.e. a chain wheel 9b (Figures 19,
20 and 23) -, in order to raise the upper sections 3 of the oven to
allow access to the interior of the oven. The main reason for this
lifting the upper 3 sections of the oven is to allow eva
cook out of the oven the glass which would have broken during the heating of the
another reason for accessing the interior.
laughter of a conventional glass-tempering oven consists in keeping the worm away
re (which is electrically conductive in the molten state) of heating elements
bare electric gloves, or keep it away from steel plates that protect
these electric heating elements. This problem is eliminated, or at least substantially alleviated, thanks to the invention.

The drive means 7 may for example be a pneumatic cylinder
conventional actuated according to the usual mode, or an electric motor coupled to a conventional device for transforming a rotary movement into a linear movement, for example a pulley and a cable, or a gear and rack mechanism, or any other mechanism
suitable for directly ordering shaft 8. As a variant,
the drive means 7 may simply consist of a spring
compensation or balancing, according to the specific requirements of a
installation determined for tempering glass.

 Air lines 11 direct air from a blower (not shown) to respectively upper 12 and lower 13 plenum chambers, from which air is ejected through rows of nozzles cooling 14 and 15.

The control panel 16 includes a control unit for DC motors (not shown) of conventional design, such as that manufactured by Polyspede Electronics Corp. from Dallas1Texas
(USA), model number PRD 8-300 "Regenerative Drive System"; many
temperature control instruments, timers, and a bi-directional preset meter.

In FIG. 1, the temperature controller 17 effectively controls the temperature produced by the electric heating elements 93 in a first upper zone of the oven, which does not necessarily correspond to a first separate section 3 of the oven,
The temperature controller 18, in an analogous manner, reverses the temperature in a first lower zone of the oven, while the temperature controllers 22 and 23 ensure the control of the heating elements 94 in the upper and lower sections of a second zone. from the oven.

 The timers 19 and 20 are used in conjunction with a bi-directional preset counter 21 to determine the time during which a piece of glass must remain in a specific area of the oven.

The counter 21, which may for example be of the type shown by
Electronic Counters & Controls, Inc., of Mundelein, Illinois (USA), with two rows of rotary switches, to digitally select the duration of a dane cycle or transfer cycle, as well as the duration of an oscillation cycle. The active range of the counter 21 is chosen by a timer 19 or 20, and the counter 21 receives a position representation by the encoder 24 (Figure 2). The use of these devices to ensure infinitely variable substance positioning and the oscillation of pieces of glass makes it possible to empirically determine the treatment parameters which will give the best results in a given job.

 Doors 25 are arranged at the two ends of the sections of the oven. The role of these doors 25 consists in protecting the interstices through which the laminating glass enters and leaves the oven with respect to any cold air currents which could damage internal temperatures and produce uncontrolled coolings and ruptures. Each door 25 comprises two pneumatic cylinders 26 actuated in synchronism with the movement of the glass in order to push the door panels 27 upwards in guides 28.

 These doors 25 increase the possibility of gaping side openings without loss of internal heat from the oven. Air pressures generated at the two ends of the furnace, and which are consequently evacuated by these openings, would produce pronounced overheating of the drive belts and of the members relating thereto.

 As shown in Figures 1 and 2, two endless belts 29 extend over the entire length of the machine, between processing wheels 30 and idler wheels 31 which also serve to tension these belts. The construction of the machine (Figures 16 to 20 and 23) is designed so as to reserve a gap 32 between the upper profile of the chassis-support 33 and the bottom profile of the chassis-support 34, the interval within which an endless belt 29 can scroll past the wheels 30 and 31.

In conventional machines, a metal strap is first placed on the machine, then the ends are connected while it is in the service position. Once this metal belt has been put in place, it is impossible to completely remove the roughness of the welded joint, so that the belt, which indirectly supports the glass being processed, causes intermittent deformation of the glass. This has the consequence of making one piece of glass optically defective every thirty or forty pieces processed.
With the present invention, it is possible to form a belt 29 outside the machine, and thus obtain a perfectly smooth connection.

 Another cause of optical deformation of the glass softened by heating in a tempering furnace lies in the vibrations due to the environment and also to the operation of the machine itself.

A closed, woven polyester loop is used, which is covered with a layer of silicone rubber before assembly, in order to obtain the strap 29. The resilience and the damping effect of the fabric and of the rubber act as vibration isolator. A suitable material for making such a belt is found in the
Globe Albany Corp. from Buffalo (NY, USA) this product being designated by this manufacturer under the name: IWP-3 Untreated Silicone COS.

 The belts of traditional machines are supported so that they can slide on flat surfaces. However, this constitutes a potential source of vibrations by friction effect alternating adhesion and sliding, while posing problems of alignment to achieve a truly flat surface. These problems are solved by the invention. The belts 29 are supported by anti-friction rollers 40 (Figures 1, 3 to 11, 18 to 23), mounted in adjustable supports 41 which are distributed over the entire length of the machine and are fixed in an adjustable manner on the profiles chassis 42 and 42a. These belts 29 only serve as drive members, and should not be confused with a support system. The frame elements 42a (Figures 1 and 16) are relatively narrow in order to reduce the resistance offered to the air.

 As shown in Figures 5, 6 and 7, each support roller 40 is constituted by a tubular element 43, two bearing caps 44 and a central axis 45. The roller supports 41 are adjustable by means of a stop screw 46 which bears against the profile 42. As soon as the desired orientation of the support 41 has been obtained by acting on the screws 46, these are blocked with nuts 47. The supports 41 are fixed by bolts 48 in the profiles 42.

 Once the adjustment of the supports 41 has been completed in order to obtain a flat support surface, the belts 29 which are supported on the rollers 40 are mounted.

 Conveyor rollers 54 and 55 intended to support the glass to be treated are then placed on the belts 29, and prevented from moving laterally by means of adjustable guides 50 (Figures 3, 4, 10 and 11}. These guides 50 have notches 51 which retain the rollers, as well as mortises 52 in which engage bolts 53 to allow the adjustment of the guides 50. As the notches 51 wear, the guides 50 can be adjusted so that they have surfaces free from roller wear.

 According to the invention, at least two basic types of transport rollers are provided, namely the high temperature ceramic rollers 54 and the low temperature rollers 55. Although the first 54 can be used throughout the machine , in the preferred embodiment, they are only provided between sections 3 and 4 of the furnace, while the second 55 are mounted in the loading section 1, in the quenching section 5 and in the unloading section 6.

 Each roller 54 consists of a ceramic shaft 56, drilled with a blind hole 57 at each end to frictionally retain pins 58a therein. According to a preferred embodiment, these pins 58a are made of rigid non-metallic material, for example Teflon. This offers several advantages. The pins 58a can easily be replaced when they are worn, and they do not tend to cause the shafts 56 to rupture in the event of overheating or differential expansion. The adoption of replaceable pins 58, together with the guide 50, practically eliminates floating or lateral movement, as well as deflection, which constitute complementary sources of vibrations which risk deforming or scratching the ammoli glass. , the ceramic shaft 56 is shouldered at each end so as to be able to adjust an elastic sleeve 59 which is flush with the surface of the shaft 56. This sleeve 59 can be used to further reduce vibrations, if necessary. This same sleeve 59 does not hinder the evacuation of the broken glass, which is done by simply pushing it through the rollers 55 and beyond the opposite side of the machine.

 The construction of the so-called low temperature rollers 55 is shown in FIGS. 11 to 15. Tubular members 60 are provided at each end with end caps 6î of which an integral part of the pins 58b can be retained in the notches 51 of the guides 50. Each tubular member 60 has several grooves with a square bottom 63 which serve to retain cylindrical washers 62 made of rubber. These grooves 63, and consequently the washers 62, are arranged at close intervals at the two ends of the corresponding tubular member 60. , and are distributed over the remainder of these members 60 according to two different modes of spacing, so that the washers 62 can be made to alternate between them on intermediate parts of adjacent rollers 55.

 Figures 8 and 9 show shoes 65 for conveyor rollers. As can be seen from Figures 16 to 20 and 23, the shoes 65 with conveyor rollers rest on an upper surface of the lower sections 4 of the furnace, and support a lower surface of the upper sections 3 of the furnace, while serving as insulators for reduce heat loss where the rollers 54 enter the furnace heating chamber.

 Figures 16 and 17 show a cooling unit.

The lateral sections 33 of the upper frames and the upper and lower sections 33a and 33b of these frames support the upper 12 and lower 13 plenum chambers respectively. In the section shown, the plenum 13 is supported in an adjustable manner by bolts 66 locked in position by nuts 67 on either side of rails 33c fixed to the lower cross members 33b of the chassis. The upper plenum 12 is supported by the section 33a in a similar fashion. This allows an easy adjustment of the distances between the series of cooling nozzles 14 and 15, on the one hand, and a glass plate supported by the rollers 55, on the other hand, and to vary the force and the distribution or the spreading of cold air to achieve optimal cooling rates. The series of cooling nozzles 14 and 15 can optionally be produced by welding complementary stamped plates 68 and 69 together, and by filling the open ends with platelets that fit and are welded on site. Preferably, the upper and lower cooling nozzles should be oriented against each other, in order to produce vertical forces which compensate each other. The nozzles forming adjacent rows should preferably be offset from each other to ensure a uniform distribution of cold air. In the embodiment shown, this is obtained by using only two different parts which are brought together repeatedly to obtain several nozzles 70 from each set of two stamped sheets 68 and 69.

 Figures 21 and 22 show details of the loading and unloading sections. In Figure 21 we see the arrangement adopted for tensioning the belts 29 in the unloading section 6.

On each side of the machine there is provided a chassis 71 essentially comprising two elements 72 forming V-shaped ridges designated at 73, which conform to the V-shaped shape of the grooves of rollers 75 mounted idly in rotation in consoles 75. These consoles 75 are rigidly fixed in appropriate parts of the chassis 71.

 Inside each frame 71 is mounted an adjustment slide 76 also having V-shaped ridges 77 formed by elements 78. A guide roller 79 provided with a V-shaped groove of corresponding shape is mounted for rotation on a shaft 80 carrying the corresponding wheel 31 and is locked using a threaded rod 81.

This, together with a nut and a lock nut 82, is used to adjust the position of the shaft 80 in the frame 71 and the adjustment slide 76, and constitutes a convenient mechanism to compensate for the elongation of the belt. 29. The tension of this belt 29 can be kept constant either by a pneumatic cylinder 83 which exerts pressure against the slide 71 (as shown in Figure 21), or by any other suitable means.

 Figure 19 shows a second embodiment of the section of the oven where the upper part 90 of an upper section 3 of the oven is fixed or stationary, and in which the side wall elements 91 and 92 are movable to allow access to the heating chamber.

 Figure 20 shows a third embodiment of an oven section, which should be noted more particularly the guide means provided to move the whole of the upper section 3 of the oven by the use of a wheel chain 9b.

 Figure 23 shows a fourth embodiment of the upper section 3 of the furnace, in which the upper parts 90 ′ of the elements 91 t and 92! side walls are movable independently of one another to allow an interval of variable importance to be obtained between the heating elements and the glass being processed.

 One aspect of the invention resides in the adoption of roller tracks which support the drive belts of the conveyor.

This arrangement appreciably reduces the friction which otherwise occurs in systems with sliding belts, which increases the useful life of the belts and reduces the energy required to drive them. In the present invention, the rollers are arranged below the conveyor drive belts.

 Another aspect of the invention relates to the positioning means which have the role of ensuring the relative spacing of the transport rollers and which are adjustable in order to represent a new wear surface when necessary. This eliminates the floating or linear movement of the rollers.

 Furthermore, an important characteristic of the invention lies in the fact that the dimensions of the heating zone are closer to those of the piece of glass to be treated. The glass is subjected to an alternating movement of the order of 15 cm, or less, in both directions, during the heating and subsequent cooling. In other known installations, the glass being treated moves at least over the entire length of the part being treated.

 On the other hand, the invention provides means for regulating the stroke achieved during the period of reciprocating movement, so that it corresponds to the length of the glass product. This reduces the risk of overheating of the product at the ends thereof by limiting contact with the hot transport rollers. Thanks to the invention, it is possible to modify the distance that the glass product travels during its back-and-forth movement in the oven.

Known installations cannot ensure this modification.

The invention provides fully adjustable systems with rollers and belt supports, around a central axis, to control the horizontal plane of the path and thus maintain a conveyor bed exactly level. The level of the transport bed is indeed a critical element with regard to obtaining a quality product,
The invention further provides an oven construction which allows the use of endless conveyor belts, free of visible connections or elements divided into segments. The consequences of the connections and / or segmentation are to lift the rollers of the conveyor bed each time it crosses any zone provided with such rollers. This lifting is transferred to the product if it is in the passage on the roller considered, and this during the phase when the product being treated has been softened by heat. It is obvious that, in this case, the final product will be of inferior quality or distorted.

 The invention provides a modular construction by zones, which makes it possible to provide both an increase and a subsequent reduction in production by the arrangement or on the contrary the dismantling of one or more heating zones, and the extension or shortening of drive belts. No other modification is required to lengthen or shorten the installation.

 Another aspect of the invention resides in the adoption of Teflon and / or silicone rubber pins, which is wear-resistant and which can be discarded after use, instead of the normally removable steel pins used. in conventional installations. This reduces the cost of replacing the ceramic rollers due to wear of the pins.

 A further aspect of the invention is the incorporation of a flexible and heat-resistant fabric, which is coated with Teflon and / or silicone rubber. This results in a reduction in the wear of the end pins of the ceramic rollers, as well as an increase in the driving forces transmitted to the transport rollers, and the elimination of the use of large diameter pulleys (such as pulleys giving a ratio of 1000 to 1 between their diameter and the thickness of the belt; in addition, with the invention it is no longer necessary to provide an additional supply of heat to maintain the linearity of the path of the belts; in addition, eliminating the use of an abrasive device for flushing the recesses formed in a belt surface, and eliminating any system of greasing the pins,

Claims (13)

 1. Installation for tempering glass, characterized in that it comprises  a) an oven formed by an upper section (3) and a lower section (4) which define a heating chamber which extends in the horizontal direction;  b) several first heating means (93, 94) arranged inside said upper section (3);  c) a first set of casings (2) to support said upper section (3);  d) a second set of chases (42) for supporting said lower section (4);  e) several supports (41) for first adjustable rollers (40), arranged on an upper surface of said second set of frames (42);  f) a flexible and endless belt (29) supported at least in part by said supports (41) with adjustable first rollers (40) s  g) several first elongated ceramic rollers (54) distributed along said chamber;  h) these elongated rollers (54) are supported by said belt (29) and extend inside and across said chamber (3, 4);  i) the elongated rollers (54) comprise non-metallic cylindrical pins (58a) housed and retained in friction in openings (57) provided at each end of these elongated rollers (54), coaxial with the latter;  j) adjustable guide members (50) comprising at least one elongated opening (51) for receiving one of the above-mentioned cylindrical journals (58a) which is retained in one of these elongated rollers;  k) a loading section (1) comprising third chassis connected to the second chases (42);  1) several roller supports (41) arranged on an upper surface of said third chassis  m) the belt is supported by the rollers (40) of said supports (41) g  n) second elongated rollers driven by said belt;  o) these second elongated rollers have ends provided with pins (58b) intended for other housed in rotation in notches (51) provided in said guide members (50);  p) a cooling unit comprising several roller supports for supporting a part of said belt;  q) means for ensuring the training of said belt, comprising control members to ensure that said court  turning the wheel alternately makes said first and second rollers in a first direction, then in the opposite direction, according to an adjustable amplitude of rotation and at an equally adjustable rotation speed, and to produce a prolonged and unidirectional rotation of said first and second rollers at a adjustable speed after a determined number of said alternating rotations, so that a glass sheet placed on the second rollers in said loading section is transferred into said heating chamber subjected to adjustable oscillations at several determined locations inside the oven, then in said cooling unit to undergo other oscillations, and finally in said unloading section.  2. Installation according to Claim 1, characterized in that said upper and lower sections, as well as the first and second casts, comprise several modular sections rigidly assembled together in order to form a single, one-piece structure for tempering the glass.  3. Installation according to Claim 1, characterized in that said upper section comprises upper and lateral parts, the upper part being fixed to the first chassis, and the lateral part being supported in an articulated manner by the first chassis so that said lateral part can be raised to allow access to the interior of the room.  4. Installation according to Claim 1-, characterized in that said upper section comprises upper and lateral parts, the upper part being supported by the first frames so as to be able to be lifted, while the lateral parts are slidably connected to said upper part, so that the lateral parts are not raised by the upward movement of said upper part as long as the latter does not bear against the highest zone of said lateral parts.  5. Installation according to Claim 1, characterized in that the length of the oscillations printed on the glass is substantially less than the length of the glass sheet.  6. Installation according to Claim 1, characterized in that the length of the oscillations printed on the glass is substantially equal to the diameter of the first roller.  7. Installation according to Claim 1, characterized in that each of said second rollers comprises a hollow tube, several circumferential grooves with a flat bottom, and cylindrical elastomer washers housed in these grooves.  8. Installation according to Claim 1, characterized in that the trunnions of the first rollers are made of non-metallic material.  9. Installation according to Claim 1, characterized in that each of the first rollers is provided with elastic sleeves which cover the two ends.  10. Installation according to Claim 1, characterized in that said lower section is provided with second heating means housed inside this section, while these second heating means are less in number and in flow than the first heating means .  11. Installation according to Claim 1, characterized in that it further comprises doors arranged near the two ends of the furnace in order to substantially reduce the flow of air towards the interior of the furnace, and that these doors are raised automatically during said unidirectional rotation of the support rollers in order to allow the transfer of the glass sheets to the interior and to the exterior of the oven.  t2. Installation according to any one of Claims 1 to 11, characterized in that the belt is made of non-metallic material.  13. Installation according to any one of Claims 1 to 11, characterized in that said belt comprises a heat resistant fabric and coated with an elastomer also resistant to heat.  14. Installation according to any one of Claims 1 to 13, characterized in that the control means are designed in such a way that the belt rotates the first and second rollers alternately in a first direction, then in the opposite direction, with an amplitude of rotation electronically adjusted and at an adjustable speed of rotation, said belt further rotating the first and second rollers in a unidirectional and prolonged fashion at an adjustable speed, after a determined number of said alternative rotations.