Roller Hearth Furnace

Abstract

A furnace of the type for heating sheet glass including a housing supported by a framework. A pair of spaced parallel rows of ceramic blocks are disposed in end to end relationship and extend through the furnace. A pair of metal endless-loop belts are entrained about wheels disposed exteriorly of the furnace with the upper reach of each belt disposed upon and movable along the upper planar surface of the ceramic blocks, the lower reach of each belt being disposed exteriorly of the housing and supported by the framework. A plurality of ceramic rollers rest upon and extend between the belts and brackets and are disposed between the rollers for preventing the rollers from moving longitudinally relative to the furnace. Heating means are disposed within the furnace, and as the steel belts move, the rollers rotate to move sheets of glass through the furnace to be heated.

Description

This invention relates to a furnace of the type utilized for treating sheets of glass as by heating the sheets of glass for tempering or annealing. One of the major problems associated with such furnaces is the conveyance of the sheet of glass through the furnace as the sheet of glass is heated to a temperature sufficient for tempering or annealing.

One type of assembly for conveying sheets of glass through a furnace which has been used in the past is one utilizing rollers.

The simplest form of such roller conveyors in glass furnaces is one wherein the ends of, or shafts extending from the ends of, the rollers extend from the interior through the sides of the furnace to external gears, pulleys, or the like, which rotate the rollers. The problem with such assemblies is that it is very difficult to maintain all of the rollers at the same rotary speed or the same surface speed, i.e., the tangential speed in a plane tangent to the tops of the rollers. Two rollers which are at slightly different speeds or having different tangential speeds in engaging a sheet of glass will mar the sheet of glass by rubbing. Additionally, there are significant heat transfer problems when a portion of a roller is within a very hot furnace and a portion extends exteriorly of the furnace into ambient conditions. Sometimes the furnace has holes therein to accommodate the rollers, and these holes make the furnace very inefficient in that a great deal of heat is lost through such holes.

Also, roller conveyors are known which are disposed entirely within a furnace. However, the rollers are mechanically supported and driven; thus, presenting the problem of keeping the rollers rotating at the same speed, plus the problem of disposing the drive means within the high temperature of the furnace. Such an assembly is shown in United States Pat. No. 3,531,274.

There are other prior art conveyors which offer other advantages but are not entirely satisfactory for conveying sheets of glass through a furnace to be heated. One such conveyor is one wherein the rollers are driven by belts. The problem with such conveyors is that the rollers are separately mounted and it is difficult to align the axis of the rollers so that there is a plane tangent to the upper surface of all the rollers. Also, the various rollers are frequently driven by different belts, thereby making it difficult to keep the rollers all rotating at the same speed. Examples of such conveyors are shown in the United States Pat. Nos. 1,883,426; 2,822,077; 2,827,153; 3,019,885 and 3,518,944.

Of course, one of the major disadvantages of using rollers which are fixedly mounted is that in order to replace a defective roller the furnace must be shut down. Another type of prior art assembly which would alleviate this problem is one wherein the rollers are freely supported on other rollers or stub shafts. The problem with such assemblies is, of course, that it is very difficult to align the stub shafts so that there is a plane tangent to the upper surface of all the rollers supported by the stub shaft. Examples of such prior art assemblies are shown in the United States Pat. Nos. 1,791,404; 1,923,815 and 2,023,126.

Accordingly, it is an object and feature of this invention to provide an improved apparatus of the type for treating sheet material including an elongated housing with a conveyor assembly extending through the housing and including support surface means for establishing a planar surface extending through the housing with a plurality of rollers supported by the planar surface so that the vertical position of the upper tangent of each roller is determined by the planar surface and drive means for effecting rotation of the rollers whereby sheet material may be moved through the housing while supported on the rollers.

In correlation with the foregoing object and feature, it is another object and feature of this invention to provide such an apparatus wherein the drive means includes a belt means disposed upon and moveable over the planar surface with the rollers being freely disposed upon the belt means for rotation thereby so that the planar surface and the taut belt establishes a precise plane upon which the rollers roll.

In correlation with the foregoing objects and features, it is another object and feature of this invention to provide control means for limiting movement of the rollers relative to the housing, whereby a defective roller may be merely lifted out of position and replaced with a new roller.

In correlation with the foregoing objects and features, it is another object and feature of this invention to provide such an apparatus wherein the support surface means is defined by at least one block the upper surface of which defines the planar surface.

Other objects and attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a fragmentary elevational view of a preferred embodiment of the instant invention;

FIG. 2 is a fragmentary end view of the preferred embodiment of the instant invention;

FIG. 3 is a fragmentary side elevational view partially broken away and in cross-section of a module of the preferred embodiment of the instant invention;

FIG. 4 is a fragmentary side elevational view of one of the blocks utilized in the instant invention to define the planar surface over which the belt moves to rotate the rollers and showing the control means disposed between the rollers for limiting movement of the rollers;

FIG. 5 is a fragmentary cross-sectional view taken substantially along line 5--5 of FIG. 4;

FIG. 6 is a fragmentary view taken substantially along line 6--6 of FIG. 5;

FIG. 7 is a view similar to FIG. 5 but showing an alternative embodiment of the control means and the rollers;

FIG. 8 is an enlarged fragmentary cross-sectional view taken substantially along line 8--8 of FIG. 7;

FIG. 9 is a view showing the drive wheels for driving the belt upon which the rollers are supported in the preferred embodiment;

FIG. 10 is a view taken substantially along line 10--10 of FIG. 9;

FIG. 11 is a fragmentary elevational view of the second or idle wheels at the other end of the furnace about which the belt is entrained and showing tensioning means for applying tension to the belt; and

FIG. 12 is a view taken substantially along line 12--12 of FIG. 11.

Referring now to the drawings wherein like numerals indicate like or corresponding parts throughout the several views, a preferred embodiment of the instant invention is generally shown at 20. As alluded to above, the apparatus 20 is a furnace for treating sheets of glass by heating the sheets of glass to temperatures sufficient for annealing or tempering.

The apparatus 20 is of the type for treating sheet material and includes an elongated housing defined by a plurality of modules each of which includes a housing section 22, which is in turn supported by framework 24. The housing 22 is defined by a metal enclosure lined with firebrick so as to be insulated and includes heat transfer means or heating means comprising the gas or electric heaters 26, as shown best in FIG. 2. Each module of the housing also includes a door 28 which may be raised to allow access to the interior of the housing.

The apparatus also includes a drive wheel assembly, generally shown at 30, disposed adjacent one end and exteriorly of the housing and a second or idler wheel assembly, generally shown at 32, disposed adjacent the other end exteriorly of the housing. A loading station which is not shown is disposed adjacent the drive wheel assembly 30. An unloading station and a quenching or tempering section are disposed adjacent the idler wheel assembly 32, neither of which are shown. Such stations are well known in the art. Although the wheel assemblies 30 and 32 are illustrated as being exteriorly of the housing, they may of course be disposed within the housing.

The conveying assembly, which includes the drive wheel assembly 30 and the idler wheel assembly 32, also includes support surface means for establishing a planar or support surface extending through or within the housing. More specifically, the support surface means is defined by a plurality of ceramic blocks 34 which are disposed entirely within the housing. The blocks are narrow and rectangular and the upper surface of the blocks define the planar surface 36. There are a plurality of blocks 34 disposed in parallel spaced rows to establish a pair of parallel spaced planar surfaces 36. The blocks are disposed in end to end relationship with a space or gap between blocks.

The apparatus also includes a plurality of rollers 38 or 38' supported by the planar surfaces 36 so that the upper tangent of each roller 38 remains at a substantially constant distance above the planar surface 36. In other words, each planar surface 36 establishes a plane for positioning the rollers 38 so that there is another plane formed by the tangents to the upper surface of the rollers 38 if all of the rollers are of the same diameter, or, said another way, the planar surface 36 establishes a plane for accurately positioning the rollers 38. The rollers are preferably made of a material having a very low coefficient of thermal expansion of not more than 1 .times. 10.sup.-.sup.6 /.degree. C as well as excellent shock resistance. The rollers may be made of fused quartz having a coefficient of thermal expansion of 0.54 .times. 10.sup.-.sup.6 /.degree. C. The temperature within the furnace will normally be between 1,200.degree. and 1,400.degree. F.

There is also included a drive means comprising the drive wheel assembly 30, the idler wheel assembly 32 and belt means defined by the belts generally indicated at 40. Each belt 40 has an active upper or driven reach 42 and a vertically spaced lower or return reach 44. As stated above, the entire drive means may be disposed entirely within the housing to conserve heat and promote temperature uniformity. The drive means effects rotation of the rollers 38 whereby sheet material, as shown in phantom at 46, may be moved through the housing while supported on the rollers 38. The sheet material is normally defined by a plurality of discreet sheets of glass although the assembly is suited to treating a continuous sheet of material. The belts 40 are disposed upon and movable over the planar surfaces 36 and the rollers 38 are disposed upon the belts 40 and are rotated thereby. Thus, the rollers 38 are supported on the planar surfaces 36 through the driven reaches 42 of the belts 40. The belts 40 are of a precise thickness and are taut and straight and therefore the vertical position of the rollers 38 is accurately determined and controlled; that is, it is directly related to the planar surfaces 36. It will be appreciated that because the belts are taut they will bridge gaps in the planar support surface yet properly vertically position the rollers. As stated above, there are spaces or gaps between adjacent blocks 34 which the belts bridge or span. In addition, the belts may be out of contact with the planar surfaces substantial distances in the event a block is not positioned properly or has non-planar surface, as by having a valley between the ends thereof. Further, it will be appreciated that even if the diameter of the rollers are different from roller to roller, the tangential or linear surface speed of the rollers will all be the same because all of the rollers are rotated at the same tangential speed by the belts 40 which impart rotation to all of the rollers.

The apparatus also includes control means comprising the brackets generally indicated at 48 and 48' for limiting movement of the rollers relative to the housing 22. Each bracket 48 and 48' extends upwardly between adjacent rollers 38 and is entirely below the uppermost point on the surface of the roller 38 so as not to interfere in any way with the movement of the sheets of glass 46 through the apparatus. Each bracket 48 and 48' extends upwardly from the planar surface 36 of the block 34 and is dipsosed between two of the rollers 38. Each block 34 has a plurality of spaced slots 50 extending downwardly thereinto from the upper planar surface 36 on each side thereof, as that illustrated in FIGS. 5, 7 and 8. Each bracket includes a fence portion 52 which extends across the planar surface 36 for limiting movement of the adjacent rollers 38 longitudinally of the housing. Each bracket also includes arms 54 extending downwardly from the fenced portions 52. One arm of each bracket 54 is disposed in a slot 50 on one side of a block 34 while the other arm 54 is disposed in a slot 50 on the other side of the block. The lower extremity of each fenced portion 52 of each bracket 48 and 48' is disposed or spaced above the planar surface 36 of the associated block 34 so that the upper reaches 42 of the belts 40 are disposed on the planar surfaces 36 between the arms 54 of the brackets and spaced beneath the fenced portions 52, as best illustrated in FIGS. 5 and 7. The bottoms of the arms 54 of the brackets 48 shown in FIGS. 4 and 5 engage the bottoms of the slots 50 to thereby vertically position the brackets 48. In contra-distinction, the alternative brackets 48' include fingers 56, as shown in FIGS. 7 and 8, which extend laterally from opposite sides of each arm 54 for engaging the planar surface 36 for vertically positioning the fenced portions 52 thereof. The fingers 56 also function to hold the brackets 48' down when the fences 52 thereof are engaged by a rotating roller because that roller will be disposed above as over the adjacent fingers 56.

Additionally, the brackets 48' each include a flange 58 extending laterally from one end of the fenced portion 52 thereof for limiting longitudinal movement of the adjacent roller 38 transversely of the housing. The brackets 48' are identical so that the brackets 48' along the planar surface 46 of one block 34 limit longitudinal movement of the rollers 38 in one direction while the brackets along the planar surface 36 of the outer spaced block limit longitudinal movement of the rollers 38 in the other direction. In other words, the rollers 38', as shown in FIG. 7, have their longitudinal movement to the right limited by the flanges 58' of the brackets 48' on the right, whereas movement to the left is limited by the flanges 58 of the brackets 48' on the left.

As shown in FIGS. 2, 5 and 7, the rollers 38 and 38' extend between the two rows of parallel blocks 34 and have their ends disposed or resting upon the active or upper reaches 42 of the belts 40. As illustrated in FIGS. 5 and 6, the end portions of each roller 38 disposed over or resting upon the active reaches 42 of the belts 40 are smaller in diameter than the immediately adjacent portion in the direction of the opposite ends for maintaining the rollers properly positioned. More specifically, as illustrated, the rollers 38 have raised portions or ridges 60 extending thereabout which are of a larger diameter than the end portions resting upon the active reaches 42 of the belts 40. Therefore, should the rollers tend to cock or move out of a position which is perpendicular to the desired travel of the glass, a ridge 60 will contact the adjacent belt and being of a larger diameter will move the roller faster, thereby returning the roller to the proper alignment. When the rollers are perpendicular to the belts the glass sheets will move in a direction parallel to the belts; however, should the rollers be non-perpendicular to the belts the sheets of glass will not move parallel to the belts. Thus, the automatic alignment of the rollers also automatically causes the sheets of glass to move parallel to the belts as desired. It will be appreciated that all that is necessary is a larger diameter portion adjacent the portion of the roller engaging the belts in order to accomplish this purpose.

The rollers 38' differ from the rollers 38 in that although the rollers 38 and 38' are made of ceramic, the rollers 38' are hollow, as best illustrated in FIG. 8. The advantage of hollow rollers is that the rollers will flex if they become eccentric or not perfectly straight so that when a sheet of glass moves thereover they will straighten instead of lifting the glass off of adjacent rollers. Additionally, hollow rollers are less likely to sag under their own weight.

It will be appreciated from the description thus far that should one of the rollers 38 or 38' become defective all that is necessary is that the defective roller be removed from the furnace between spaced sheets of glass moving therethrough and replaced by a new roller without at all disrupting the flow of sheets of glass through the furnace.

Since the position of the upper planar surfaces 36 of the blocks 34 is very critical, requiring the blocks 34 to be properly positioned, there is also included adjustment means for adjusting the position of the blocks 34 so as to adjust the position of the planar surface 36. As alluded to before, the blocks 34 are disposed in parallel rows and the blocks of each row abutt one another in end to end relationship with a space between the ends of adjacent blocks. The framework 24 includes a pair of spaced and parallel beams 62 which extend lengthwise below the housing 22. The adjustment means includes a pair of first and second support shafts 64 and 66 wlich which connected to the beams 62 and extend into the housing 22 to adjustably support the blocks 34. Each block 34 has associated therewith a first support shaft 64 and a support shaft 66. Each block 34 includes a pair of lugs 68 extending downwardly from the bottom surface. Each first shaft 64 has a channel 70 at the upper end thereof engaging the lower extremity of and disposed about opposite ends of one of the lugs 68 for moving the associated block longitudinally of the housing upon arcuate movement of the first shaft 64 about its connection to the beam 62. Each of the second support shafts 66 has a plate 72 at the upper end thereof engaging the lower extremity of the other lug 68 of the associated block for allowing the block to move freely longitudinally of the housing. In order to move the first support shaft 64 in an arcuate path, the adjustment means also includes an eye bolt 74 having one end or a ring 76 surrounding the first shaft 64 and operatively connected to the adjacent beam 62 by a threaded shank and a channel member 78. Longitudinal adjustment of the eye bolt 74 moves the first support shaft 64 in an arcuate path to adjust the longitudinal position of the associated block 34. It should be appreciated that the arcuate movement of the first support shaft 64 is very minimal as the longitudinal movement of the blocks 34 for adjustment is very minimal.

As alluded to hereinbefore, the housing includes a plurality of modules disposed in end to end relationship, and each module has a plurality of the blocks 34 disposed therein. FIG. 3 illustrates one such module, and as illustrated the module includes two blocks 34 in each row for a total of four blocks 34. As mentioned hereinbefore, the door 28 may be raised for providing access to the interior of the housing. There are included compressible or expandable sealing means disposed between the ends of adjacent modules for allowing the modules to expand and contract independantly of one another.

As is clear from the drawings, each belt 40 comprises an endless loop having an active reach 42 disposed over the planar surfaces 36 of the blocks in one row, whereas the other reach or lower reach 44 is disposed exteriorly of the housing. A support means, which includes a plate 80 and hangers 82 connected to the beams 62, supports the lower reaches 44 of the belt 40.

The drive wheel assembly 30 includes a pair of spaced drive wheels 84 disposed adjacent a first end and exteriorly of the housing and the belts 40 are entrained about the drive wheels 84. The idle wheel assembly 32 includes a second pair of spaced wheels 86 disposed adjacent the other end and exteriorly of the housing and the belts 40 entrained thereabout.

The belts 40 are preferably made of alloy steel or refractory metal such as a chrome nickel alloy and the ratio of the diameter of the wheels 84 or 86 to the thickness of the associated belt 40 is preferably no less than 1,000 to 1 to prevent injury to the belts by exceeding their elastic limits which for the annealed metals preferably used is approximately 30,000 p.s.i. and the Youngs Modulus 3 .times. 10.sup.7 p.s.i. It will be appreciated that the belts may be made of other materials including chains and mesh.

The drive wheel assembly 30 also includes a pair of electric motors 88. Each motor 88 operatively drives one of the drive wheels 84 through a pinion 90 and a large gear 92. The pinion gear 90 is driven through a gear box 94. The gear boxes 94 are best illustrated in FIG. 10, and are coupled together by a coupler 96, thereby coupling the drive wheels 84 together for rotation at the same speed so that both belts 40 move at the same linear speed, thereby rotating all of the rollers 38 at the same surface or tangential speed.

The idle wheel assembly 32 includes a carriage means comprising a frame 98 which supports rods or guides 100, which in turn support the second pair of wheels 86 for movement longitudinally of the belts 40. There is also included belt tensioning means comprising the air cylinders 102 and cables 104 entrained about pulleys 106 for controlling the tension on the belts 40. The wheels 86 are supported by housings 108 which are in turn slidably supported on the rods 100, there being two rods 100 associated with each housing 108. Thus, the force applied through the cables 104 by the air cylinders 102 determines the tension on the belts 40.

A crown is included in the wheels for centering the belt on the wheels. In other words, the wheels 84 and 86 may have a crown therein for centering the associated belt thereon.

Each drive wheel 84 is supported by a frame 110 and each frame 110 is in turn supported by a base 112. The frame 110 is supported on the base 112 for pivotal movement about an axis extending through the center line of the associated belt 40. More specifically, as shown in FIG. 10, the forward portion of the frame 110 is connected to the base 112 through a fastener or bolt 114, the center line of which or longitudinal axis of which extends through the center line of the associated belt 40. There is also included means, generally indicated at 116, to pivot the frame 110 about the axis of the bolt 114 to adjust the position of the frame 110 relative to the base 112 to properly align the associated drive wheel 84. Bolts 118 lock the bases 110 in the desired position.

As alluded to herein above, the surfaces of the belts 40 are critical. For example, a small bit of grit or the like may be disposed between the belt and the surface of one of the wheels 84 and 86 as one of the belts passes thereover to thereby cause a bulge or dimple in the belt which would in turn cause undesirous vertical movement of the rollers as the belt moves thereunder. Therefore, the apparatus includes an abrasive means, generally indicated at 120 in FIG. 3, for engaging the surfaces of the belt for maintaining the surfaces of the belt within predetermined tolerances. Such abrasive means will remove such dimples or similar imperfections.

In some instances it may be desirous to heat the belt before it enters the housing so that there is not a sudden rise in temperature of the belt as it leaves ambient conditions and moves into the housing. Furthermore, the belt in its natural state or due to operating conditions may be slightly curved, and it therefore may be desirous to heat the belt with heating means capable of supplying heat with a temperature gradient across the belt as by heating the belt along one edge as it is moving through the furnace to straighten out the belt and guide it along the desired path. Various heat transfer means may be utilized to provide such a temperature gradient across the belt. A means for so heating the belt exteriorly of the housing is generally shown at 122 in FIG. 9.

It also may be desirous to provide a lubricant between the ends of the rollers 38 and 38' and the belts 40 and the brackets 48 and 48'. Such a lubricant accomplishes three purposes. First it prevents excessive wear of the belt, particularly when the rollers are made of ceramic. Secondly, should the glass be stopped or retarded, lubrication between the belt 40 and the rollers 38 and 38' will allow slippage between the belt 40 and the rollers 38 and 38' instead of between the rollers 38 and a sheet of glass, which would, of course, mar the surface of the glass. Thirdly, the lubricant will retard or prevent wear of a roller should it be prevented from rotating.

The invention has been described in an illustrative manner and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that with the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Claims

We claim:

1. Apparatus for treating sheet material comprising: an elongated housing; a conveyor assembly adapted to carry said sheet material in a direction of travel substantially parallel to the longitudinal axis of said elongated housing, said conveyor assembly including first and second spaced apart support surfaces for establishing a substantially planar surface extending in a direction substantially parallel to the longitudinal axis of said elongated housing; a plurality of elongated rollers extending transversely of said elongated housing, each of said rollers spanning the gap between said first and second support surfaces; and friction drive means coupled with said rollers for effecting rotation of said rollers whereby sheet material may be moved through said elongated housing while supported by said rollers.

2. An apparatus as in claim 1 wherein said friction drive means includes a belt disposed for movement over one of said first and second support surfaces, said rollers being disposed upon said belt such that said rollers are rotated upon movement of said belt.

3. An apparatus as in claim 2 including means for placing said belt in tension.

4. An apparatus as in claim 2 including a control means for limiting movement by said rollers in the plane of said belt.

5. An apparatus as in claim 4 wherein said control means allows each roller to be lifted from said belt.

6. An apparatus as in claim 2 wherein said friction drive means includes a second belt disposed for movement over the other of said first and second support surfaces, said rollers being disposed upon said second belt such that said rollers are rotated during movement of said second belt.

7. An apparatus as in claim 6 including means for placing said first and second belts in tension.

8. An apparatus as in claim 7 including means to synchronize movement by said first and second belts.

9. An apparatus as in claim 6 including heat transfer means within said elongated housing.

10. An apparatus as in claim 9 wherein said first and second belts are disposed in relation to said rollers such that the portions of said rollers adapted to contact said sheet material are entirely between said belts and exposed continuously to said heat transfer means.

11. An apparatus as in claim 6 wherein said belts are disposed within said elongated housing.

12. An apparatus as in claim 4 wherein said rollers are disposed entirely within said elongated housing.

13. An apparatus as in claim 6 including heat transfer means capable of effecting a temperature gradient across said continuous belts.

14. An apparatus as in claim 6 wherein said first and second support surfaces are discontinuous and wherein said first and second belts respectively bridge the discontinuities along said first and second support surfaces.

15. An apparatus as in claim 14 wherein said discontinuities in said first and second support surfaces define independently adjustable support surface members disposed in parallel rows with the individual support surface members of each row nearly abutting one another in spaced end to end relationship.

16. An apparatus as in claim 15 wherein the ends of said rollers are carried by and located relative to said support surface members.

17. An apparatus as in claim 16 including adjustment means for independently adjusting the longitudinal position of each support surface member and the roller ends associated therewith.

18. An apparatus as in claim 6 wherein said rollers have substantially equal diameters along the portions thereof engaging said belts and along the portions thereof adapted to engage said sheet material whereby the lineal velocity of said sheet material will be substantially the lineal velocity of said belts.

19. An apparatus as in claim 6 wherein said first and second belts are continuous and wherein said first and second belts are disposed respectively for movement upon and over said first and second support surfaces such that said first and second belts define said substantially planar surface extending in the direction substantially parallel to the longitudinal axis of said elongated housing.

20. An apparatus as in claim 19 wherein said elongated housing is insulated, includes heat transfer means within said elongated housing, and wherein said rollers and said continuous belts are disposed within the insulated portion of said housing.

21. An apparatus as in claim 20 wherein said friction drive means includes a pair of spaced drive wheels disposed adjacent a first end of said elongated housing, said belts being entrained about said drive wheels, and a second pair of spaced wheels disposed adjacent the second end of said elongated housing.

22. An apparatus as in claim 21 wherein said continuous belts comprise chain link belts.

23. Apparatus for treating sheet material comprising: an elongated housing; a pair of spaced parallel continuous belts, one of said belts extending longitudinally of said housing along one side thereof and the other of said belts extending longitudinally of said housing along the other side thereof; a plurality of elongated rollers extending transversely of said housing, each of said rollers spanning the gap between and having end portions respectively resting upon said belts; and drive means for effecting movement of said belts to thereby effect rotation of said rollers whereby sheet material may be moved through said housing while supported by said rollers.

24. An apparatus as in claim 23 wherein said belts establish a substantially planar surface upon which said rollers are disposed.

25. An apparatus as in claim 24 wherein said belts are placed in tension to establish the substantially planar surface upon which said rollers are disposed.

26. An apparatus as in claim 25 wherein said belts comprise chain link belts.

27. An apparatus as in claim 23 including control means for limiting the movement of said rollers in the plane of said belts.

28. An apparatus as in claim 27 wherein said control means allows each roller to be lifted from said belts.

29. An apparatus as in claim 23 including a pair of parallel spaced apart surfaces, one of said belts being disposed for movement over one of said surfaces, the other belt being disposed for movement over the other of said surfaces.

30. An apparatus as in claim 29 wherein said surfaces are discontinuous and wherein said belts bridge the discontinuities along said surfaces.

31. An apparatus as in claim 30 wherein said belts establish a substantially planar surface upon which said rollers are disposed.

32. An apparatus as in claim 31 including heat transfer means within said housing.

33. An apparatus as in claim 31 including heat transfer means capable of effecting a temperature gradient across said belts.

34. An apparatus as in claim 31 wherein said belts are disposed within said housing.

35. An apparatus as in claim 34 wherein said rollers are disposed entirely within said housing.

36. An apparatus as in claim 23 wherein the sheet contacting portions of said rollers are entirely between said belts.

37. An apparatus as in claim 36 including means to synchronize movement by said first and second belts.

38. An apparatus as in claim 37 wherein said housing is insulated, includes heat transfer means within said housing, and wherein said rollers and said continuous belts are disposed within the insulated portion of said housing.

39. Apparatus for treating sheet material comprising: an elongated housing; a continuous belt extending in a direction substantially parallel to the longitudinal axis of said elongated housing; a plurality of elongated rollers extending transversely of said elongated housing, each of said rollers having a portion engaging said continuous belt, the length of each of said rollers being substantially greater than the width of said belt, said rollers being adapted to support relatively wide sheet material throughout the expanse of said sheet material in the direction transverse to said elongated housing; and drive means for effecting movement of said belt to thereby effect rotation of said rollers whereby sheet material may be moved through said elongated housing while supported by said rollers.

40. An apparatus as in claim 39 including means for placing said belt in tension.

41. An apparatus as in claim 39 wherein said rollers have substantially equal diameters along the portions thereof engaging said belt and along the portions thereof adapted to engage said sheet material whereby the lineal velocity of said sheet material will be substantially the lineal velocity of said belt.

42. An apparatus as in claim 39 wherein said belt is disposed along one side of said elongated housing.

43. An apparatus as in claim 42 including a second belt disposed along the other side of said elongated housing, said rollers being disposed upon said second belt such that said rollers are rotated during movement of said second belt.

44. An apparatus as in claim 43 including means for placing said first and second belts in tension.

45. An apparatus as in claim 44 including means to synchronize movement by said first and second belts.

46. An apparatus as in claim 44 wherein said first and second belts are disposed in relation to said rollers such that the portions of said rollers adapted to contact said sheet material are entirely between said belts.

47. An apparatus as in claim 43 including a pair of parallel spaced apart surfaces, one of said belts being disposed for movement over one of said surfaces, the other belt being disposed for movement over the other of said surfaces.

48. An apparatus as in claim 47 wherein said surfaces are discontinuous and wherein said belts bridge the discontinuities along said surfaces.

49. An apparatus as in claim 48 wherein said belts establish a substantially planar surface upon which said rollers are disposed.

50. An apparatus as in claim 49 including control means for limiting the movement of said rollers in the plane of said belts.

51. An apparatus as in claim 50 wherein said control means allows each roller to be lifted from said belts.

52. An apparatus as in claim 51 wherein said elongated housing is insulated, includes heat transfer means within said elongated housing, and wherein said rollers and said continuous belts are disposed within the insulated portions of said housing.

53. Apparatus for treating sheet material comprising: an elongated housing; a continuous belt extending longitudinally of said housing along one side thereof; a plurality of rollers extending transversely of and having axial central portions within said housing; a plurality of spaced support surfaces extending along one side of said housing; a plurality of roller retainers carried by said support surfaces for respectively positioning said rollers; adjustment means for each of said support surfaces for controllably adjusting the position of said respective surface to thereby respectively adjust the positions of the rollers associated with said surface by said roller retainers; and drive means for effecting movement of said belt to thereby effect rotation of said rollers whereby sheet material may be moved through said housing while supported by said rollers.

54. An apparatus as in claim 53 wherein said support surfaces nearly abut one another in spaced end to end relationship.

55. An apparatus as in claim 54 including adjustment means for independently adjusting the longitudinal position of each support surface and the roller ends associated therewith.

56. An apparatus as in claim 54 including a second plurality of spaced support surfaces extending along the other side of said housing.

57. An apparatus as in claim 56 wherein said support surfaces are disposed in two parallel rows with the surfaces of each row nearly abutting one another in end to end relationship.

58. An apparatus as in claim 57 including adjustment means for independently adjusting the longitudinal position of each surface and the roller ends associated therewith.

59. An apparatus as in claim 58 including a second continuous belt.

60. An apparatus as in claim 59 wherein each of said continuous belts is disposed for movement over one of said rows of support surfaces, said rollers being disposed upon said belts such that said rollers are rotated upon movement of said belts.

61. An apparatus as in claim 60 including means to synchronize movement by said belts.

62. An apparatus as in claim 60 wherein said belts establish a substantially planar surface upon which said rollers are disposed.

63. An apparatus as in claim 62 wherein said belts are placed in tension to establish the substantially planar surface upon which said rollers are disposed.

64. An apparatus as in claim 63 wherein said elongated housing is insulated, includes heat transfer means within said elongated housing, and wherein said rollers and said continuous belts are disposed within the insulated portion of said housing.