US1853879A - Insulated leer roller - Google Patents

Description

April 12, 1932-- E. W. PAXTON ET Al.

INSULATED LEER ROLLER Filed March 8, 1950 F'lgv.

F195. mw vx@ /lo Patented Apr. 12, 1932 UNITED STATES PATENT oFFlcE ELISHA W. IAXTON ANDI .ARTHURv W. SCHMID, F WASHINGTON, PENNSYLVANIA,

ASSIGNORS T0 HIGHLAND-WESTERN GLASS COMPANY, OF WASHINGTON, PENN- SYLVANIA, A CORPORATION 0F DELAWARE INSULATED LEER ROLLER Application filed March -8,

This invention relates to improvements in supportlng rolls for sheet glass in glass annealing leers and it is among the objects thereof to provide improved supporting rolls ,for

sheet glass annealing leers which are adapted transverse thermal balance during the coolelevation of the leer ing or annealing period.

Another object of the invention is the provision of a roll structure adapted to control the heat losses in a manner to produce proper thermal conditions at the surface of the rolls which contact with the glass sheet.

Another object of the invention is the provision of roll structures and the application of cooling media thereto which shall provide positive means for controlling the heat losses from the hot sheet material supported thereby, and from the contacting portions of the rolls.

These and other objects will become more apparent from a consideration of the accompanying drawings in which like reference characters designate like parts and in which Fig. 1 is a cross sectional lview of an improved form of roll forsheet glass annealing leers embodying the principles of this invention; Figs. 2 and 3 are similar views of modications of the invention; Fig. 4 a cross sectional view of another type of roll designed to function in accordance with the stated objects of the invention; Fig. 5 a similar'view of another modication of the roll; Fig. 6 a longitudinal sectional view of a portion of a glass annealing leer showing the customary arrangement of the glass supporting rolls; and Fig. 7 a cross sectional view partially in structure shown in Fig. 6.

With reference to Figs. 6 and 7 of the drawings, 1 designates the roof or top wall of a glass annealing leer; 2 the side walls; 3 rolls which are preferably driven by suitable actuating mechanism; 4 designates the bottom wall of the leer and 5 designates the wall which cooperates with the bottom wall 4 to form a. heating or cooling flue employed in 1930. serial No. 432,329.

-controlling the temperature within the muie or leer chamber,

In the operation of the leer, the sheet glass 1s entered at the passage 7 and is conveyed longitudinally of the leer by the rolls 3 on which the hot sheet glass is supported; and during its travel through the leer the sheet is subjected to the proper annealing or cooling temperatures until it nally is discharged from the leer in the proper annealed and cooled state.

In the application of a roll type of leer to the manufacture of continuous sheet glass, the sheet glass is conducted from the sheet forming pass of the forming rolls directly into the annealing leer and if the thermal conditions of the forming rolls are balanced, the glass will be of substantially uniform temperature transversely of its length.

It has been found that ydue to the construction of metal sheet supporting rolls with solid ends andshafts, as heretofore employed, it is difficult to maintain the sheet glass in transverse thermal balance during lts passage through the leer, this being partially due to the large loss of heat from the axial sections of the supporting rolls. Since the rolls are essentially journalled at their respective ends, the easiest path of travel of heat from the rolls is by conduction through their ends, and on account of the relatively heavy journals, heat loss is greater at or near the ends of the rolls. For this reason it has been necessary in the prior art to supply additional heat in the annealing chambers toward the edges of the glass sheet in an effort to neutralize the loss of heat at these points.

This method has undesirable features such as diiiiculty ofv controlling the corrective heating; necessity of .continual regulation; cost of fuel; additional length of leer necessary to properly dissipate the added heat, and the fact that its whole purpose has been corrective rather than preventive.

In accordance withv the present invention, the proper thermal balance transverse of the sheet is maintained by the inherent structural characteristics of the supporting rolls and without the necessity of adding any heat to the leer adjacent the ends of the rolls, with its attendant requirement of additional leer length to dissipate such added heat.

With reference to the drawings in Fig. 1, the roll 3 is shown as provided with a central spider 8 which is optional and for mechanical support only, and4 end spiders 9 which are formed integrally with or mounted on a hollow shaft 10. The spokes of the spiders are of minimum cross section and constitute relatively small heat conducting paths from the roll shells 3 that are in contact with the hot glass 11 which they support, to the roll shafts 10.

In accordance with the present invention, an insulating or baffle structure, generally designated at 13, is provided at the ends of the rolls 3 and is in spaced relation with the rolls as shown at 14. The battle structure may consist of any suitable material of relatively low heat conducting qualities, as for example, asbestos, and this can most conveniently be provided in the form of a series of discs 15 which are arranged in the manner shown and held in their respective positions by an end collar 16.

VViththis arrangement, it will be seen that a relatively free heat radiating space is provided at the central portionof the rolls and the bale structure 13 isetfective in producing a muile effect that sets up a heat lag which greatly impedes the heat radiation at the portions of the rolls adjacent the baille member. Since, as previously explained, the loss of heat from the roll shell through conductivity to its shaft is reduced to a minimum, it remains only to offset or neutralize that minimumby utilization of available radiation and for this purpose the roll construction is specifically designed to provide for radiation from shell to shaft nearthe center of the rollstructure. p

By employing the hollow shafts 10,- the temperature of the rolls may be further controlled by conducting a suitable cooling Inedium, such as air or water, through thehollow shafts. Since the maximum heat radiation from roll shell to shaft is effected at the central portion of the roll, as explained above, the corresponding portion of the hollow shaft will be the hottest and by setting up a forced circulation of cooling medium in the shaft the heat is removed from the shaft by conduction and convection and con sequently from the roll shell by radiation and convection, at this central portion. By controlling the length of the baille structure 15 in accordance with the ph sical Vdimensions and thermal properties o the roll, and the width and temperature of the sheet glass, a transverse thermal balance may be effectively produced or maintained in the sheet glass 11 throughout the annealing range of the leer.

In Figs. 2 and 3 are illustrated modifications of the form of baffle structure as shown in Fig. 1, for example, in Fig. 2 the asbestos sheet discs are of gradually decreasing diameter, thus forming a conical shaped baffle which increases the width of the space 14 so as to obtain a gradual increase of heat radiation towards the cent-er of the roll. This is equally obtainable by a structure shown in Fig. 3 in which the air gap or space between the roll and baflie structures is varied by assembling a series of discs of different diameters to produce the steps or sections 17.

As shown in Fig. 4, the roll may he constructed without the use of battles of the type described in connection with Figs. 1,2 and 3, to bring about a maximum loss of heat at the central portion of the rolls. This may be effectively obtained by supporting the rolly3 on a hollow shaft 18 having an expanded central portion 19 which is in contact with the roll 3. Disposed in the roll is a conduit 20 leading to the expanded portion of the hollow shaft. This conduit functions to conduct a cooling medium to the interior of the roll which is passed out through the respective ends of the hollow shaft and maintains a cooling effect on the center portion of the roll structure similar to that obtainable by the provision of means for controlling and/or localizing the heat radiation as hereinbefore explained.

In the modification shown in Fig. 5, the roll 3 is provided with a hollow shaft 10 having a bushing 21 interposed between the roll and the shaft, which bushing is of substantial length and provides a maximum surface area of contact with the roll 3 to produce a maximum loss of heat through conduction at its central portion. The bushing 21 may be provided with grooves 22 of variable size, depth, and/or spacing, to reduce its conduction capacity near the ends thereof so that the loss of heat is gradually tapered off from the center in the direction of the ends of the roll.

It is apparent from the foregoing description of this invention that proper thermal balance may be obtained transversely of the sheet glass by controlling the loss of heat by means of suitable construction and design of the leer rolls, namely, by so constructing said rolls that their heat conducting and radiating properties are controlled. By the use of this invention, the annealed glass is of a more nearly uniform quality and free from strains and no applied/heat is necessary to maintain the proper thermal conditions in the al1- nealing leer during the critical or annealing range of the glass.

Although one embodiment of the invention has been herein illustrated and described, it will be obvious to those skilled inthe art that various modications may be made in the details of construction without departing from the principles herein set forth.

WVe claim:

1. A roller for conveying sheet material through an annealing chamber comprising a roll-shellka shaft supported in said shell con-v nections for said shell and shaft Whic are adapted to minimize the loss of heat by conduction from the shell to said shaft and baillev means for effecting radiation of heat at the center of the roll-shell and for controllin the amount of heat radiation from shell tos aft through the length ofthe said shell.

an annealing chamber, each comprising a roll-shell, a shaft for journalling said shell,l means for supporting said roll-shell and shaft in radially spaced relation and insulating meansv disposed between said shaft and the said shell out of contact with the latter, and adjacent the end of the rolls to reduce the heat radiation losses from the roll shell to the shaft 'adjacent the ends of the rollshells.v

3. Rollers/for an annealing chamber, each comprising a roll-shell, a shaft fbr journalling said shell, means for supportin shaft in radially space ing bushings disposed between said roll shell and shaft` for reducing the heat radiation losses adjacent the ends of the roll. 4. On a roll structure for conveying sheet material through an annealing chamber, the combination with a roll shell of a supportin shaft therefor and means on said s aft an in spaced relation with said shell for controlling the loss of heat through conduction and heat radiation to obtain a thermal balance between the roll-shell and consequently'in the sheet material supported thereon.

In testimony whereof we have hereunto set our hands this 30th day of January, 1930.

ELISI-IA, W. PAXTON. ARTHUR W. SCHMID.:v

relation, and insulat- 2. Rllers for supporting sheet material in supporting sheet'material in l said roll-shell and` l

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