GB2244549A

GB2244549A - Chain conveyor kilns

Info

Publication number: GB2244549A
Application number: GB9012009A
Authority: GB
Inventors: Jan Komar
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-05-30
Filing date: 1990-05-30
Publication date: 1991-12-04
Anticipated expiration: 2010-05-30
Also published as: GB9012009D0; GB2244549B

Abstract

A tunnel kiln 10 suitable for firing ceramic ware 12 and having a heating chamber 14 has a pair of parallel driven endless chains 16 extending adjacent the exterior of the chamber 14 one on each side thereof in an upper pass. A plurality of recrystallised silicon carbide beams 18 extend between the chains 16 transversely to the direction of movement thereof defining a movable grid. The grid moves through the chamber 14 in the upper pass of the chain 16 permitting ware 12 to be supported thereon. <IMAGE>

Description

Kilns This invention concerns improvements in or relating to kilns and particularly but not exclusively tunnel kilns.

Tunnel kilns are used in a number of fields and are particularly useful for heat treating ceramic articles. A shortcoming with tunnel kilns, as with conventional kilns, is that a considerable amount of heat is wasted in heating the components used to support the ware or the other articles being heated. This is particularly the case when kiln cars are employed.

According to the present invention there is provided a kiln comprising a heating chamber, a plurality of beams connected to a drivable endless elongate means for movement of the beams through the chamber, the beams being arranged in a spaced relationship relative to each other, transversely aligned relative to their direction of movement, to provide a support grid for articles being heated in the heating chamber.

The beams are preferably formed of recrystallised silicon carbide. The beams may be hollow and preferably have a substantially square cross-section.

Two elongate means are preferably provided spaced from each other. The elongate means are preferably connected to each of the beams adjacent respective ends thereof.

The or each elongate means may comprise a chain.

The elongate means may be located outside of the heating chamber. Carriers may be provided at spaced locations on the elongate means with the carriers mounting respective ends of the beams. The carriers preferably extend through openings in the walls of the heating chamber.

The openings preferably have such a profile as to provide a contorted path for warm air escaping from the chamber. The profile of the openings may be stepped and the carriers may be correspondingly shaped to slidingly fit therein.

Loading and unloading areas are preferably provided on said one pass adjacent respective ends of the heating chamber.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic cross-sectional end view through a part of a kiln according to the invention; and Fig. 2 is a diagrammatic cross-sectional side view of the kiln of fig. 1.

The drawings show a tunnel kiln 10 suitable for firing ceramic ware 12. The kiln 10 includes a heating chamber 14. A pair of parallel driven endless chains 16 are provided, extending adjacent the chamber 14 one on each side thereof in an upper pass. The chains 16 are driven by any suitable motor or the like in a clockwise direction as illustrated by the arrow 17 in fig. 2. A plurality of beams 18 extend between the chains 16, transverse to the direction of movement thereof, and are mounted thereon by carriers 20. The beams 18 define a movable grid which moves through the chamber 14 in the upper pass of the chains 16, onto which the ware 12 may be placed, usually on batts 22. Kiln loading and unloading areas 24,26 are provided respectively immediately upstream and downstream of the chamber 14.

Fig. 1 shows the construction of the chamber 14 in more detail. The chamber 14 comprises top, side and bottom walls 28,30,32 lined with refractory material.

Electric heating elements 34 are provided on each of the walls 28,30,32.

An opening 36 is provided on each side of the chamber 14 between the side and bottom walls 30,32. The openings 36 comprise a first lateral portion extending from the interior of the chamber 14 leading into a downwardly extending portion with two outward steps, facing towards the upper pass of the chain 16.

The carriers 20 comprise an upright member 38 extending from the chain 16 into the lateral portion of the opening 36, and a stepped sleeve 40 fitted around the member 38 corresponding in profile to the downward extending portion of the opening 36 to slidingly engage therein. The upper end of the member 38 mounts an end of one of the beams 18. The beams 18 are formed of square sectioned recrystallised silicon carbide tubing.

There is thus described a tunnel kiln with a number of advantageous features. The use of the recrystallised silicon carbide beams permits a relatively open support structure to be used due to the good load bearing capability of this material even at high working temperatures. This structure accordingly has a low thermal capacity and thus absorbs less heat than a conventional arrangement. The open structure provides for even heating throughout the chamber. The provision of the chain outside of the heating chamber means that no heat is wasted in heating up the chain and further less maintenance problems are likely to be experienced therewith. Further the contorted profiling of the opening through which the carriers extend reduces the amount of heat lost therethrough.The kiln is of relatively basic construction and thus can be readily manufactured and run with very low maintenance costs.

Various modifications may be made without departing from the scope of the invention. For example the openings in the heating chamber may be differently shaped. The carriers may have a different construction. The heating chamber may be heated using gas or infra red heating. The spacing between the beams can obviously be chosen to suit the loads to be applied thereon, and this can vary from 7-100cm. If required an elongate means other than chains could be used.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

Claims:

1. A kiln comprisng a heating chamber, a plurality of beams connected to a drivable endless elongate means for movement of the beams through the chamber, the beams being arranged in a spaced relationship relative to each other, transversely aligned relative to their direction of movement, to provide a support grid for articles being heated in the heating chamber.

2. A kiln according to Claim 1, in which the beams are formed of recrystallised silicon carbide.

3. A kiln according to Claims 1 or 2, in which the beams are hollow.

4. A kiln according to any of Claims 1 to 3, in which the beams have a substantially square cross-section.

5. A kiln according to any of Claims 1 to 4, in which two elongate means are provided spaced from each other.

6. A kiln according to Claim 5, in which the enlongate means are connected to each of the beams adjacent respective ends thereof.

7. A kiln according to Claim 6, in which carriers are provided at spaced locations on the elongate means with the carriers mounting respective ends of the beams.

8. A kiln according to any of the preceding Claims, in which the or each elongate means comprises a chain.

9. A kiln according to any of the preceding Claims, in which the or each elongate means is located outside of the heating chamber.

10. A kiln according to Claim 9 when dependent on Claim 7, in which the carriers extend through openings in the walls of the heating chamber.

11. A kiln according to Claim 10, in which the openings have such a profile as to provide a contorted path for warm air escaping from the chamber.

12. A kiln according to Claim 11, in which the profile of the openings is stepped.

13. A kiln according to Claim 12, in which the carriers are correspondingly shaped to slidingly fit in the openings.

14. A kiln according to any of the preceding Claims, in which loading and unloading areas are provided adjacent respective ends of the heating chamber.

15. A kiln substantially as hereinbefore described with reference to the accompanying drawings.

16. Any novel subject matter or combination including novel subject matter disclosed in the foregoing specification or claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding claims.