Title:
INTERNALLY FLUID COOLED ROTATABLE ROLL
United States Patent 3802495
Abstract:
Apparatus for effecting coolant fluid flow, in two directions, through the hollow interior of a rotatably mounted conveyor type roll. A coolant supply or withdrawal tube is inserted through one of the open ends of the central core of the roll, and depending upon the function of the tube, the open ends serve as coolant exits or entrances, respectively.
US Patent References:
Cooled furnace transport rollers
Schmidt - August 1963 - 3100631
Driving roller in a roller conveyor for use at high temperatures
Ericsson - December 1963 - 3116053
METHOD OF EVACUATING ENTRAPPED GASES IN LIQUID COOLED FURNACE ROLLS AND APPARATUS THEREFOR
Cavitt - July 1969 - 3455541
Cooled furnace transport rollers
Schmidt - August 1963 - 3100631
Driving roller in a roller conveyor for use at high temperatures
Ericsson - December 1963 - 3116053
METHOD OF EVACUATING ENTRAPPED GASES IN LIQUID COOLED FURNACE ROLLS AND APPARATUS THEREFOR
Cavitt - July 1969 - 3455541
Application Number:
05/290015
Publication Date:
04/09/1974
Filing Date:
09/18/1972
View Patent Images:
Export Citation:
Assignee:
Combustion Engineering, Inc. (Windsor, CT)
Primary Class:
Other Classes:
432/236, 165/DIG.160, 432/228, 432/60, 432/246
International Classes:
B65G39/00; C03B35/18; F16C13/00; F27D3/02; C03B35/00; F27D3/00; C21D9/00
Field of Search:
165/89 432/236,60,228
Primary Examiner:
Davis Jr., Albert W.
Assistant Examiner:
Richter S. J.
Attorney, Agent or Firm:
Goettel Jr., Frederick A.
Claims:
What is claimed is
1. An internally fluid cooled rotatable roll comprising:
2. The apparatus of claim 1 wherein the opening in said other open end comprises a plug, having an orifice of a predetermined size therethrough, disposed in said other open end.
1. An internally fluid cooled rotatable roll comprising:
2. The apparatus of claim 1 wherein the opening in said other open end comprises a plug, having an orifice of a predetermined size therethrough, disposed in said other open end.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to rotatable rolls that are subjected to high temperatures and more particularly to apparatus for effecting internal fluid cooling of such rolls.
2. Description of the Prior Art
The present invention may be used in conjunction with conveyor rolls of the type used for transporting workpieces, such as glass, ceramic or metals through high temperature ovens. The invention is particularly applicable for use in cooling the large rolls commonly used in glass processing apparatus such as annealing or tempering ovens for conveying the product sheets therethrough. Such rolls may be eight to ten feet in length, are very heavy and are subjected to extremely high operating temperatures. Rolls of this type typically comprise steel cores on which are assembled a plurality of asbestos washers; the washers being highly compressed and held in their compressed condition on the steel core. The compressive force on the asbestos washers creates an internal gripping force of the washers on the steel core and as a result the asbestos rotates with the core to carry the glass along.
Past experience has shown that the high temperatures to which such rolls are exposed cause a number of life shortening results. Thermal expansion of the steel core will tend to release some of the initial compressive force applied to the asbestos washers at the time of fabrication. It has also been found that at high temperatures the asbestos deteriorates at an undesirable rate. This deterioration is reflected in a weight loss and a decrease in density and physical strength. As this deterioration progresses, the asbestos washers loose their grip upon the steel core and eventually rotate freely about it.
It has thus been recognized that cooling of the core and the asbestos covering will give longer roll life at all operating temperatures. Prior art cooling arrangements have included flowing a cooling medium such as air or water through the roll core from one end to the other. Such systems obviously result in non-uniform cooling because the coolant fluid heats up as it progresses through the core. Also, due to the characteristics of the furnaces in which they are used, such rolls are normally subjected to higher temperatures at their longitudinal centers. Various techniques have been suggested to achieve a more uniform temperature distribution along the length of the roll, such as for example the roll of U. S. Pat. No. 3,466,722 where an internal deflector is proposed to vary the coolant flow velocity and thus the rate of heat exchange. Such a system still suffers from the first drawback mentioned above, i.e., the coolant temperature rises as it flows through the core, and thus the temperature of the roll is higher at the exit end.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to apparatus for internally cooling a rotatable roll having a hollow core wherein the cooling fluid is caused to flow in two streams either toward or away from a point within the hollow core. Such flow patterns tend to minimize the heating effects of the coolant which have made the one-way flow techniques unacceptable. The ends of the hollow roll core are open and a tube is extended through one of the open ends to the interior of the core. By connecting an air pump or vacuum pump to the other end of the tube, cooling fluid is supplied to or withdrawn, respectively, from the core. When cooling fluid is pumped into the core through the tube, it flows out of the core in two streams; one through each of the open ends of the core. Conversely, when a vacuum is applied to the other end of the tube cooling fluid, typically all is withdrawn from the core and is replaced by cooling air drawn into the core through each of the open ends.
It is thus a primary object of this invention to provide an internally fluid cooled rotatable roll overcoming the disadvantages of previous one-way coolant flow designs.
It is an object of one embodiment of this invention to provide an internally fluid cooled roll whereby the lowest temperature coolant is supplied to the hottest region of the roll, and whereby the coolant temperature rises as it passes to the lower temperature zones; thus resulting in a substantially uniform roll temperature.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view partially in section of a roll in accordance with the present invention;
FIG. 2 is a section taken on the lines 2--2 of FIG. 1;
FIG. 3 is an enlarged view of a portion of FIG. 1;
FIG. 4 is a section taken on the lines 4--4 of FIG. 3;
FIG. 5 is a schematic showing of one operating embodiment of the invention; and
FIG. 6 is a schematic showing of a second operating embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1, a rotatable roll 10 having an elongated hollow metal core 12 including oppositely spaced open ends 14, 16 is shown mounted for rotation in bearing structures 18. The hollow core 12 is comprised of a large cylindrical center portion 13 and spindle extensions 15 attached to and extending from each end of the center portion 13 for engaging the bearing structures 18. The core 12 carries on its outer surface a glass contacting covering comprised of asbestos washers 20 which are held axially in compression by suitable means 22 as is conventional. Extending through one of the open ends 14 of the core 12 is a hollow tube 24 having a diameter less than that of the interior of the core to define an annular passage 26 therebetween, as best shown in FIG. 2. This passage, as will be subsequently further described, may serve as a coolant outlet or inlet depending on the mode of operation of the system. The end 25 of the tube 24 extending into the interior of the core 12 is open to effect fluid communication therebetween.
Referring to FIGS. 3 and 4, the other of the open ends 16 of the core 12 is shown including a threaded plug 28 having an orifice 30 therethrough. The plug 28 is screwed into mating threads 32 in the interior of the core 12. For approximately uniform flow throughout the core interior the cross-sectional area of the orifice 30 is equal to the cross-sectional area of the annular passage 26 defined in the end 14 of the core 12 through which the hollow tube 24 is inserted. If a more precisely uniform flow is desired throughout the core interior the cross-sectional area of the annular passage 26 must be somewhat greater than the cross-sectional area of the orifice 30 to allow for the greater frictional flow resistance in the annular passage 26.
FIGS. 5 and 6 schematically illustrate two operating embodiments utilizing the invention. In FIG. 5 the end of the hollow tube 24 extending out of the core 12 is coupled to a conventional source of cooling fluid 34 which may be a fan, air pump, or a water pump, or the like. The coolant fluid is continuously pumped into the interior of the core 12 through the open end 25 of the tube 24. The open end 25 is preferably located at the longitudinal center of the core 12 so that maximum cooling is effected at the normally hotter center of the roll 10. The air exiting from the tube 24 into the core interior then follows two flow paths to exit from the core 12. A portion passes through the core and out through the orifice 30, and a portion passes through the annular passage 26 and out the open end 14. As pointed out above if the cross-sectional areas of the orifice 30 and the annular passage 26 are equal, an equal volume of cooling fluid will pass through each side of the roll.
The embodiment shown in FIG. 6 uses a vacuum pump or the like 36 in place of the air pump previously described. The vacuum pump 36 draws coolant from the interior of the core 12 through the hollow tube 24. In turn, coolant fluid which is typically atmospheric air is drawn into the core through the annular passage 26 and the orifice 30. Such an arrangement is advantageous if it is desired to cool the large bearing structures supporting the roll and it also permits conveniently exhausting the hot coolant to a point remote from the work area such as outside the plant.
Both of the described embodiments achieve a balanced cooling effect within the roll not heretofore obtainable with the one-way flow cooling techniques previously used.
While the invention has been shown and described in connection with illustrative embodiments, it is to be understood that changes may be made without departing from the spirit and scope of the invention as claimed.
1. Field of the Invention
This invention relates to rotatable rolls that are subjected to high temperatures and more particularly to apparatus for effecting internal fluid cooling of such rolls.
2. Description of the Prior Art
The present invention may be used in conjunction with conveyor rolls of the type used for transporting workpieces, such as glass, ceramic or metals through high temperature ovens. The invention is particularly applicable for use in cooling the large rolls commonly used in glass processing apparatus such as annealing or tempering ovens for conveying the product sheets therethrough. Such rolls may be eight to ten feet in length, are very heavy and are subjected to extremely high operating temperatures. Rolls of this type typically comprise steel cores on which are assembled a plurality of asbestos washers; the washers being highly compressed and held in their compressed condition on the steel core. The compressive force on the asbestos washers creates an internal gripping force of the washers on the steel core and as a result the asbestos rotates with the core to carry the glass along.
Past experience has shown that the high temperatures to which such rolls are exposed cause a number of life shortening results. Thermal expansion of the steel core will tend to release some of the initial compressive force applied to the asbestos washers at the time of fabrication. It has also been found that at high temperatures the asbestos deteriorates at an undesirable rate. This deterioration is reflected in a weight loss and a decrease in density and physical strength. As this deterioration progresses, the asbestos washers loose their grip upon the steel core and eventually rotate freely about it.
It has thus been recognized that cooling of the core and the asbestos covering will give longer roll life at all operating temperatures. Prior art cooling arrangements have included flowing a cooling medium such as air or water through the roll core from one end to the other. Such systems obviously result in non-uniform cooling because the coolant fluid heats up as it progresses through the core. Also, due to the characteristics of the furnaces in which they are used, such rolls are normally subjected to higher temperatures at their longitudinal centers. Various techniques have been suggested to achieve a more uniform temperature distribution along the length of the roll, such as for example the roll of U. S. Pat. No. 3,466,722 where an internal deflector is proposed to vary the coolant flow velocity and thus the rate of heat exchange. Such a system still suffers from the first drawback mentioned above, i.e., the coolant temperature rises as it flows through the core, and thus the temperature of the roll is higher at the exit end.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to apparatus for internally cooling a rotatable roll having a hollow core wherein the cooling fluid is caused to flow in two streams either toward or away from a point within the hollow core. Such flow patterns tend to minimize the heating effects of the coolant which have made the one-way flow techniques unacceptable. The ends of the hollow roll core are open and a tube is extended through one of the open ends to the interior of the core. By connecting an air pump or vacuum pump to the other end of the tube, cooling fluid is supplied to or withdrawn, respectively, from the core. When cooling fluid is pumped into the core through the tube, it flows out of the core in two streams; one through each of the open ends of the core. Conversely, when a vacuum is applied to the other end of the tube cooling fluid, typically all is withdrawn from the core and is replaced by cooling air drawn into the core through each of the open ends.
It is thus a primary object of this invention to provide an internally fluid cooled rotatable roll overcoming the disadvantages of previous one-way coolant flow designs.
It is an object of one embodiment of this invention to provide an internally fluid cooled roll whereby the lowest temperature coolant is supplied to the hottest region of the roll, and whereby the coolant temperature rises as it passes to the lower temperature zones; thus resulting in a substantially uniform roll temperature.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view partially in section of a roll in accordance with the present invention;
FIG. 2 is a section taken on the lines 2--2 of FIG. 1;
FIG. 3 is an enlarged view of a portion of FIG. 1;
FIG. 4 is a section taken on the lines 4--4 of FIG. 3;
FIG. 5 is a schematic showing of one operating embodiment of the invention; and
FIG. 6 is a schematic showing of a second operating embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1, a rotatable roll 10 having an elongated hollow metal core 12 including oppositely spaced open ends 14, 16 is shown mounted for rotation in bearing structures 18. The hollow core 12 is comprised of a large cylindrical center portion 13 and spindle extensions 15 attached to and extending from each end of the center portion 13 for engaging the bearing structures 18. The core 12 carries on its outer surface a glass contacting covering comprised of asbestos washers 20 which are held axially in compression by suitable means 22 as is conventional. Extending through one of the open ends 14 of the core 12 is a hollow tube 24 having a diameter less than that of the interior of the core to define an annular passage 26 therebetween, as best shown in FIG. 2. This passage, as will be subsequently further described, may serve as a coolant outlet or inlet depending on the mode of operation of the system. The end 25 of the tube 24 extending into the interior of the core 12 is open to effect fluid communication therebetween.
Referring to FIGS. 3 and 4, the other of the open ends 16 of the core 12 is shown including a threaded plug 28 having an orifice 30 therethrough. The plug 28 is screwed into mating threads 32 in the interior of the core 12. For approximately uniform flow throughout the core interior the cross-sectional area of the orifice 30 is equal to the cross-sectional area of the annular passage 26 defined in the end 14 of the core 12 through which the hollow tube 24 is inserted. If a more precisely uniform flow is desired throughout the core interior the cross-sectional area of the annular passage 26 must be somewhat greater than the cross-sectional area of the orifice 30 to allow for the greater frictional flow resistance in the annular passage 26.
FIGS. 5 and 6 schematically illustrate two operating embodiments utilizing the invention. In FIG. 5 the end of the hollow tube 24 extending out of the core 12 is coupled to a conventional source of cooling fluid 34 which may be a fan, air pump, or a water pump, or the like. The coolant fluid is continuously pumped into the interior of the core 12 through the open end 25 of the tube 24. The open end 25 is preferably located at the longitudinal center of the core 12 so that maximum cooling is effected at the normally hotter center of the roll 10. The air exiting from the tube 24 into the core interior then follows two flow paths to exit from the core 12. A portion passes through the core and out through the orifice 30, and a portion passes through the annular passage 26 and out the open end 14. As pointed out above if the cross-sectional areas of the orifice 30 and the annular passage 26 are equal, an equal volume of cooling fluid will pass through each side of the roll.
The embodiment shown in FIG. 6 uses a vacuum pump or the like 36 in place of the air pump previously described. The vacuum pump 36 draws coolant from the interior of the core 12 through the hollow tube 24. In turn, coolant fluid which is typically atmospheric air is drawn into the core through the annular passage 26 and the orifice 30. Such an arrangement is advantageous if it is desired to cool the large bearing structures supporting the roll and it also permits conveniently exhausting the hot coolant to a point remote from the work area such as outside the plant.
Both of the described embodiments achieve a balanced cooling effect within the roll not heretofore obtainable with the one-way flow cooling techniques previously used.
While the invention has been shown and described in connection with illustrative embodiments, it is to be understood that changes may be made without departing from the spirit and scope of the invention as claimed.