JPS6331413B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to conveying sheets or ribbons of flat glass at elevated temperatures, and more particularly, to the conveyance of sheets or ribbons of flat glass at elevated temperatures, and more particularly to the invention. The present invention relates to an improved roll and a method for processing the roll. Such rolls are treated with a solution of potassium sulfate to greatly increase the lubricity of their surfaces and to bond their fibers together, thereby extending the life of the rolls and allowing them to be heated to temperatures not previously possible. The roll can now be used under certain conditions.

In the manufacture of flat glass, continuous ribbons or sheets of glass are typically rolled from well-known flat glass, sheet glass or float glass forming equipment onto a series of aligned rolls for conveyance through an adjacent annealing furnace. Received. When received from such a forming area, the ribbon or sheet is in a highly heated condition and the final optical quality of the glass is degraded by contact with the conveyor rolls. This is for glasses produced by the float process, and the present invention is particularly useful in such cases. As disclosed in U.S. Pat. No. 3,081,551 to Pilkington, glass produced by this method leaves the metal bath in end-use condition with a highly smooth surface. The ribbon is relatively hot, i.e.
The temperature is around 900° to 1400° (480° to 760°C),
Therefore, when removed from the metal bath, it is in a softened state, and as it passes through the annealing furnace, it is gradually cooled according to a predetermined pattern. Generally, the roll is constructed of a suitable heat resistant material, such as stainless steel or asbestos, to withstand the above temperatures while maintaining a suitable support surface.

Due to the high temperatures and the nature of the manufacturing process, glass ribbons are difficult to process, especially during the early stages of the annealing process.
It is influenced by many factors that reduce the final optical quality. That is, irregularities or defects in the roll surface will imprint corresponding flaws on the underside of the ribbon in its softened state. Such irregularities can be caused by scratches on the roll surface or deposits on the roll surface, especially in the early stages of the annealing process. That is, in the manufacture of float glass, a tin compound, usually tin oxide, is carried from a molten metal bath by a glass ribbon and deposited on a roll. Such deposits accumulate,
Deposits from the roll are imprinted on the bottom of the ribbon.
In order to reduce the effects of such deposits and extend the service life of the roll, it is recommended to treat the glass ribbon with SO ₂ gas to provide a lubricating or separating effect between the roll surface and the ribbon. , Snow U.S. Patent No.
Proposed in No. 3199966. However, such treatment itself results in the formation of a sodium sulfate deposit on the roll, which stamps the bottom surface of the glass. Further, as the rolls tend to become slightly eccentric or out of shape due to severe temperature conditions, abrasion marks or scratches are created in the glass ribbon as the rolls rotate. When rolls, especially asbestos rolls, are constantly exposed to these operating conditions, they deteriorate rather rapidly, especially at the hot or furnace end of the annealing furnace, and may have a lifespan of only a few days in some locations; Under the most severe operating conditions, the roll may become completely unusable.

Gorman ( Gorman), US Pat. No. 3,853,523. The use of potassium sulfate treated millboard or hotboard heat shields for insulation purposes in float glass manufacturing equipment is also disclosed in Daman, US Pat. No. 4,057,410, and others. The material treated in this way is said to not imprint the glass ribbon when it comes into contact with the glass ribbon.

According to the invention, the asbestos rolls used to transport the heated glass are chemically treated to increase the self-lubricating power or lubricity of the surfaces in contact with the glass. This reduces the tendency for deposits to build up on the roll surface and any defects present on the roll surface are less likely to damage the glass surface due to the self-lubricating effect. Additionally, the material used to treat the rolls penetrates the asbestos and crystallizes during drying, and these crystals serve to bind the asbestos particles together, so that the entire material is simply coated with an amorphous lubricant. The individual asbestos fibers form agglomerated nodules that are less likely to fall off than a roll or a similar untreated roll.

It is therefore a principal object of the present invention to provide a roll for conveying glass at high temperatures, in which imprinting of the roll on the supported surface of the glass is minimized.

Another object of the present invention is to provide such a roll that is less prone to surface irregularities.

Yet another object of the invention is to extend the service life of asbestos glass transport rolls.

Yet another object of the present invention is to provide a method for treating the above-mentioned rolls in order to improve both the lubricity of the roll surface and the bonding of the asbestos material.

According to the invention, in a method of treating a roll comprising an asbestos material support part for conveying glass at high temperatures, an aqueous solution of potassium sulfate is prepared and the asbestos material A method for treating a roll is provided, characterized in that the supporting part is immersed in the aqueous solution, the asbestos material supporting part is removed from the aqueous solution and dried, thereby crystallizing potassium sulfate in the asbestos.

According to the invention, there is also provided an apparatus for processing rolls including an asbestos material support part for conveying glass at high temperatures, including an enclosed kiln and a roll containing a solution to be impregnated into the asbestos material support part. a removable trough within the kiln; a retaining device for rotatably retaining the roll in the kiln with the asbestos material support portion at least partially immersed in the solution; and the trough; a drive device for rotating a roll about its longitudinal axis to sequentially immerse the circumferential surface of the asbestos material support portion in the solution when the asbestos material is in the kiln, and bringing the interior of the kiln to a selected temperature; An apparatus for treating rolls is provided, characterized in that it comprises a heating device that can be operated to maintain the temperature of the rolls.

Further, according to the present invention, in a roll for conveying glass at high temperatures and including an asbestos portion adapted to support glass,
There is provided a roll characterized in that the above asbestos is impregnated with potassium sulfate.

Referring to the drawings, FIG. 1 depicts a portion of a typical annealing furnace 10 through which a glass ribbon 11 is passed through a series of horizontally aligned driven drives, as is well known in the art. It is conveyed on rolls 12. These furnaces are equipped with heaters (not shown) to regulate the furnace temperature so that the temperature of the glass ribbon is gradually reduced according to a predetermined pattern to properly anneal the glass passing through it. It is being
The roll is normally supported at both ends by journals 13 and is driven by a gear 14 that meshes with a worm on a line shaft (not shown).

As best shown in FIG. 2, the roll 12 according to the invention has a hollow tubular mandrel 15;
Multiple asbestos discs 1 on this mandrel
6 are attached so that their end surfaces are in contact with each other. The disc 16 is axially fastened on the mandrel 15 between the end plates 17 by bolts 18. Bolt 18 extends through end plate 17 and disk 16 and has a head 19 and nut 20 which abut the outer surface of end plate 17 and which can be operated in a conventional manner to bolt disk 16. Tighten. A tapered end 21 is secured to each end of the mandrel 15 and is provided with a tubular bearing extension 22 for rotatably supporting the roll 12 in the journal 13. A gear 14 is fixed to one of the bearing extensions 22 .

Disc 16 provides a strong, dense outer surface for supporting a glass sheet or ribbon when placed under appropriate axial compression. Typically, roll 12 is turned and smoothed or otherwise finished prior to use to form a smooth cylindrical working surface for contact with the glass. According to one embodiment of the invention, after the roll 12 is thus ready for use, the central portion supporting the glass sheet is immersed in an aqueous solution of potassium sulfate, which penetrates the asbestos material. roll 1
2 is removed from the aqueous solution and allowed to air dry for an initial period before being placed in a kiln until the asbestos material is completely dry and the roll 12 reaches an equilibrium temperature approximately equal to the operating temperature within the annealing furnace 10. to,
The temperature is gradually increased in the kiln over a period of time. Typically, furnace rolls must be gradually heated to the expected operating temperature before being placed in an operating annealing furnace to prevent thermal shock damage to the rolls and glass ribbon. , a subsequent direct installation in the furnace is advantageous. Of course, the roll 12 may be cooled once and then reheated at any time as usual. It may be desirable to smooth the roll surface to remove roughness caused by potassium sulfate solution treatment. This can be done by finishing with a fine-grained stone belt. If the rolls are loaded directly into the furnace from the drying kiln, refinishing must be completed after air drying but before drying in the kiln. Of course, separate disks 16 may be immersed in an aqueous solution and assembled onto the mandrel 15 after drying.

FIG. 5 shows an embodiment of a device for processing rolls 12 according to the present invention. i.e. overall reference numeral 2
A closed kiln, indicated by 3, is provided, which kiln has a floor 24, side walls 25, a roof 26,
and an end wall (not shown). Heater 2
7 For example, an ordinary gas burner has a roof 26 and a floor 24.
A through hole 29 is formed in the side wall 25 in the recess 28 for inserting and removing the roll 1. These openings 29 may be at least partially closed around the bearing extensions 22 of the roll 12 by refractory blocks 30. dent 2
A removable trough 31 resting on the floor 24 above 8 contains an aqueous potassium sulfate solution 32 in which the lower part of the asbestos disc 16 of the roll 12 is immersed. The roll 12 is rotated in this partially immersed state so that all sections of asbestos are penetrated by the solution.
Additionally, the roll 12 must be rotated continuously while being heated in this manner to prevent warping. For this purpose, the bearing extension 22 of the roll 12
are supported in bearings 33 supported on stands 34 on both sides of the kiln 23, and a reduction gear unit 35, driven by an electric motor, is connected to the roll 12 by, for example, a sprocket 36 and a chain 37.

If the roll 12 is not properly dried before being placed in the furnace 10, or if the roll 12 is heated too quickly in a drying kiln, the moisture trapped inside the asbestos material will be converted to steam, which It has been found that when it expands and escapes to the outside, it causes decrepitation of the roll surface. To prevent this, the kiln 2 with the trough 31 removed after the outer surface moisture has been removed from the roll being processed by initial air drying.
In order to start heating the roll 12 according to a predetermined schedule, the roll 12 is placed in the heater 2.
Activate 7. More specifically, the temperature of kiln 23 is kept at about 100 °C until it reaches a temperature of about 600 °C (315.6 °C).
(37.8°C) increments, maintaining each temperature level for approximately 1 hour. Thereafter, the temperature is steadily increased to approximately 1000°C (537.8°C), then to room temperature or roll 1, as the case may be.
2 is installed directly into the furnace 10, the temperature is reduced to the expected operating temperature of the furnace 10.

An asbestos roll constructed in accordance with the present invention was prepared for use in the apparatus generally shown in FIG. Approximately 160 for trough 31
A saturated solution of potassium sulfate in hot water at a temperature of (71.1°C) was contained. The outer diameter of asbestos disk 16 is
12 inches (approx. 30.48cm), 9 inches (approx.
22.86 cm), and roll 12 was immersed in the solution to a depth of 2 inches (about 5.08 cm). roll 12
The solution was rotated in this partially immersed state for about 1.5 hours at a speed of about 22 RPM, with constant stirring during this period to homogenize the solution. After this period, the roll 12 was removed from the trough 31 and allowed to air dry overnight before refinishing the roll surface with a fine aperture belt. Next, roll 12 to kiln 2
3, and heated with constant rotation.
To do this, the heater 27 (in this case an ordinary gas burner) is activated to raise the temperature of the kiln 23.
Gradually increase in increments of 100〓(37.8℃),
The temperature was maintained at each increment from 100° (37.8°C) to 600° (315.6°C) for approximately 1 hour. Then operate the gas burner at full capacity,
The temperature was set at 1000㎓ (537.8℃). At this temperature approx.
After 1.5 hours, the burner was turned off and kiln 23 was allowed to cool.

After cooling, the roll 12 was inspected and was found to have a good appearance. Next, after preheating, roll 12 is
It was installed in position No. 6, ie, the sixth roll from the inlet end of a continuously operating float glass annealing furnace. Inspection of the rolls after 5 days of glass manufacturing operations revealed no deterioration or damage to the roll surfaces. At this time, inspect the glass,
No defects attributable to the asbestos roll 12 were observed.

It is practically impossible to operate ordinary untreated asbestos rolls in position No. 6 of a continuous furnace as described in the example above, and such rolls have a short service life of only a few hours. I don't think so. On the contrary, rolls treated according to the invention have been found to have a very long service life under the same operating conditions. Previously, the initial stage of the furnace required the use of stainless steel rolls, which required frequent cleaning or refinishing. Chrome plating the rolls requires less cleaning, but plating requires a relatively high cost. On the contrary,
Rolls according to the invention have proven to be quite satisfactory at about one-third the cost of chrome-plated stainless steel rolls.

[Brief explanation of the drawing]

FIG. 1 is a perspective view, partially in section, of a typical annealing furnace using rolls manufactured in accordance with the present invention, and FIG. 2 is a typical annealing furnace constructed in accordance with the present invention. Fig. 3 is a cross-sectional view taken approximately along line 3-3 in Fig. 2, and Fig. 4 is a cross-sectional view taken along line 4-4 in Fig. 2.
FIG. 5 is a cross-sectional view taken generally along a line, and FIG. 5 is an elevational view, partially in section, showing an example of an apparatus for adjusting rolls in accordance with the present invention. Explanation of symbols, 10...Annealing furnace, 11...Glass ribbon (glass), 12...Roll, 16...
... Asbestos disk (asbestos material support part), 23 ... Kiln, 27 ... Heater (heating device), 31 ... Trough, 32 ... Potassium sulfate solution (solution), 33 ... Bearing, 34 ... Stand, 35...
...Reduction gear unit, 36... Sprocket, 3
7...Chain.

Claims (1)

[Claims] 1. A method for treating a roll containing an outer asbestos material support portion for conveying glass at high temperatures, comprising: preparing an aqueous solution of potassium sulfate for a sufficient period of time to allow the aqueous solution to penetrate the outer asbestos; A glass conveying roll characterized in that the outer asbestos material supporting portion is immersed in the aqueous solution, the outer asbestos material supporting portion is taken out from the aqueous solution and dried, thereby crystallizing potassium sulfate in the asbestos. processing method. 2. The asbestos material supporting portion is first air-dried in an ambient atmosphere to evaporate surface moisture and then subjected to heating to gradually increase the temperature until substantially all moisture is removed. A method for treating glass conveyance rolls according to claim 1. 3. The method for treating glass conveying rolls according to claim 1 or 2, wherein the aqueous solution is a saturated solution of potassium sulfate that is stirred to maintain its homogeneity. 4 While the asbestos was immersed, the above aqueous solution was added to the
160° C. (71.1° C.). A method for treating glass conveying rolls according to any one of claims 1 to 3, characterized in that the temperature is maintained at 160° C. (71.1° C.). 5 Position the roll above the aqueous solution so that its longitudinal axis is parallel to the surface of the aqueous solution and its lower part is immersed in the aqueous solution, and rotate the roll about its longitudinal axis to 5. A method for treating a glass conveying roll according to any one of claims 1 to 4, characterized in that the peripheral surface of the asbestos material supporting portion is immersed one after another. 6 incrementally increasing the temperature to which the asbestos material support portion is exposed during application of said heating, at least partially, and maintaining the temperature at each incremental point for a sufficient period of time to gradually release trapped moisture; A method for treating a glass conveyance roll according to claim 2, characterized in that: 7 Increase the temperature from 100〓(37.8℃) to 600〓(315.6℃)
7. The method for treating glass conveying rolls according to claim 6, characterized in that the temperature is increased in increments of 100° (37.8°C) up to 100° (37.8°C), and then raised to approximately 1000° (537.8°C). 8. Claims 2, 6, or 7, characterized in that the conditioned roll is loaded into an operating glass manufacturing apparatus while the asbestos material supporting part is in a heated state. A method for treating a glass conveyance roll according to any one of the following. 9 If the aqueous solution is a saturated solution of potassium sulfate that is kept at a temperature of about 160°C (71.1°C) and stirred to maintain homogeneity while the asbestos is immersed, its longitudinal axis lies on the surface of the aqueous solution. a roll is positioned above the aqueous solution so that the roll is parallel to the aqueous solution and its lower part is immersed in the aqueous solution, and the roll is rotated about its longitudinal axis to successively immerse the circumferential surface of the asbestos material supporting portion; the temperature at which said asbestos material supporting portion is exposed when said heating is applied is 100°C.
(37.8℃) to 600〓(315.6℃) to 100〓(37.8℃)
℃), holding the temperature at each increment point for a sufficient time to gradually release the trapped moisture, and then increasing the temperature to 1000㎓ (537.8℃). A method for treating a glass conveyance roll according to item 2. 10. A roll for transporting glass, which is a roll for transporting glass at high temperatures and includes an asbestos portion that supports the glass, characterized in that the asbestos is impregnated with crystallized potassium sulfate. . 11. The glass conveying roll of claim 10, wherein the asbestos portion comprises a plurality of asbestos discs axially compressed on a central mandrel. 12. Potassium sulfate substantially penetrates the disk from the outer surface to the mandrel, and the potassium sulfate crystals provide lubricity to the glass conveying surface to bind the asbestos fibers together. A roll for glass conveyance according to Item 11.