Support Means for a Roller Hearth in a Kiln

This invention relates to a support for the ceramic rolls of the roller hearth of a kiln and in particular to a support for the rolls which will withstand the high temperatures, friction and loads present in such kilns. Kilns are old and well known in the art, and ceramic roller hearths have been used in these kilns to facilitate the passage of work through them. At present, however, the ceramic rollers of the hearth are limited in length by limitations in tube technology. Since the length of the ceramic rollers is limited, a corresponding limitation is imposed on the width of the hearth. The limitation of width necessarily limits the width of the work pieces or the number of work pieces which can be conveyed by the roller hearth at any given time. Various attempts have been made to overcome the limitations of roller tube technology, but to date no feasible or economic way has been proposed which will overcome these limitations.

The present invention provides a significant improvement in present kiln roller hearth design and construction. The invention provides a support for the ceramic rolls of the roller hearth which is economically and easily constructed and is able to withstand the temperatures, friction and loads encountered in a kiln. The invention permits ceramic rolls of greater length to be used in the roller hearths of kilns thereby permitting an increase in the size and capacity of a kiln while using existing ceramic roll technology. In a preferred form of my invention, I provide a support beam for the ceramic rolls of the roller bed of the kiln. The support beam is adapted to engage the rolls thereby supporting the rolls and providing the drive force for them. The support beam is moveable transversely of the ceramic rolls by means of a hydraulic ram. Piston means move the support means upward to engage the ceramic rolls and downward out of engagement when the drive stroke is completed.

When the hydraulic ram draws the support beam forward, the piston means and the support beam elevate it to contact the bottom surface of the individual ceramic rolls. This is the drive stroke wherein the support beams frictionally engages the ceramic rolls causing them to rotate thereby moving the work pieces through the kiln. At the completion of the drive stroke the ram returns the support beam to its original position and the piston means cause the support beam to lower out of engagement with the ceramic rolls. The cycle is repeated until all the work pieces are moved through the tunnel kiln. In the foregoing general description, I have set certain purposes, objects and advantages of my invention.

It will be described hereafter and will become apparent for those skilled in the art of the construction and operation of roller hearth tunnel kilns when considering the following description and the drawings in which:

FIG. 1 is a fragmentary longitudinal view of a tunnel kiln partly in section;

FIG. 2 is a transverse sectional view through the kiln of FIG. 1 taken on line 2--2;

FIG. 3 is a partial side elevational view of FIG. 2 as seen from the right thereof;

FIG. 4 is a fragmental longitudinal view of a tunnel kiln partly in section showing an alternative embodiment of the present invention;

FIG. 5 is a transverse sectional view through the kiln of FIG. 4 taken on line 4--4;

FIG. 6 is a fragmentary section view of an alternate center line support means of the present invention;

FIG. 7 is a sectional view taken on line 6--6 of FIG. 6;

FIG. 8 is a fragmentary sectional view of another alternative center line support means of the present invention;

FIG. 9 is a sectional view taken on line 8--8 of FIG. 8;

FIG. 10 is another alternative center line support means of the present invention;

FIG. 11 is a sectional view taken along line 10--10 of FIG. 10; and

FIG. 12 is a sectional view of an alternate embodiment of the invention.

Referring to the drawings, I have illustrated in FIG. 1 a roller hearth tunnel kiln 10 having sidewalls 11 and floor 12. The roller hearth 13 of kiln 10 is comprised of individual ceramic rolls 14. The individual rolls 14 span the width of the kiln and extend outwardly of the sidewalls 11 through apertures 15. Rolls 14 are supported by means of wheel supports 16 are fixed on shafts 17 which are rotatably mounted to the frame of kiln 10 by means well known in the art. Sprockets 18 are mounted on the fore end of shafts 17.

Referring to FIG. 2, support beam 19 which can be made of ceramic or other material of suitable strength and heat resistance is mounted in channel 20. Hydraulic piston means 21 are operably connected to support beam 19 to raise the beam to engage rolls 14 and lower the beam from engagement with said rolls. Hydraulic ram means 22 is operably connected to one end of beam 19 and moves beam 19 transversely of the individual rolls 14.

In operation, work pieces, not shown, would be placed on rolls 14 for firing while moving through kiln 10. Beam 19 would be simultaneously raised by cylinders 21 and drawn forward by ram 22. When beam 19 is raised, it would engage rolls 14 causing them to rise off the elevated section 12' of floor 12. The forward movement of beam 19 by means of ram 22 which frictionally engaging rolls 14 will cause rotation of rolls 14 thereby causing the work pieces to travel over the rolls and through the kiln. When ram 22 has reached the end of its forward stroke, the beam is lowered by cylinders 21 and returned to its original position by the return stroke of ram 22. The rolls now rest on the elevated section 12' of floor 12. The cycle is then repeated as often as necessary to move all of the work pieces through the kiln.

FIGS. 4 and 5 show one alternate form of my invention. Support blocks 23 are pushed through the kiln under rolls 14 by means of ram 24. The operation of ram 24 and the recirculation of blocks 23 are not shown but are well known and understood in the art. Support blocks 23 are made of ceramic or the like and are guided through kiln 10 by within guide channel 25. The movement of blocks 23 which frictionally engage rolls 14 would cause rotation of the rolls and movement of any work pieces through the kiln. The guide channel may have the configuration 25' as shown in FIG. 6. In this embodiment, flanged ceramic rollers 27 are interposed between support blocks 23 and channel 25'. Ceramic rollers 27' can also be placed within support channel 25 as shown in FIGS. 8 and 9. In FIGS. 10 and 11, guide channel 25 includes ceramic spacer means 28 which would retain ceramic rollers 27' in place within guide channel 25.

FIG. 12 shows another embodiment of the invention. The support system may include a plurality of support beams or guide channels. In the embodiment shown, there are two support beams 19'. Rolls 14' can be joined by members 29 to further increase the width of the hearth. Beams 19' are mounted in channels 20'. Hydraulic piston means 21' are operably connected to beams 19' to raise the beams to engage rolls 14' and lower the beams from engagement with said rolls. Hydraulic ram means 22' (not shown) are operably connected to one end of the beams 19' and move beams 19' transversely of the individual rolls 14'. The operation of each piston 21' and ram 22' is synchronized by means known and understood in the art to permit coordinated movement of beams 19'. Alternately a single piston 21" could be used with balance beam 30 to operate beams 19'.

In any of the embodiments of my invention, additional outside chain drive means for the rollers can be provided through sprockets 18 by means well known in the art.

Thus, the size and capacity of a roller hearth tunnel kiln are not limited by existing ceramic roll technology and larger and more efficient kilns can be built.

In the foregoing specification, I have set out certain preferred embodiments of my invention, however, it will be understood that this invention may be otherwise embodied within the scope of the following claims.