GB2136100A

GB2136100A - Firing carriage including a rack structure of refractory material for the ceramics industry

Info

Publication number: GB2136100A
Application number: GB08406042A
Authority: GB
Inventors: Roland Rossner; H Schwandt
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1983-03-09
Filing date: 1984-03-08
Publication date: 1984-09-12
Also published as: GB8406042D0; FR2542435A1; DE8306841U1; JPS59197792A

Abstract

A firing carriage (kiln car) includes a rack structure of refractory material, especially of cordierite material, which is composed of at least four upright continuous hollow posts (2) having transversely extending holes. Continuous transverse beams (15) are inserted into corresponding opposed holes. On top of the transverse beams are placed further continuous, longitudinal, beams (16). The longitudinal beams receive firing batts (12) for supporting articles such as plates, cups and similar articles during firing. The posts may be reinforced internally by a central wall or two opposed fins which are interrupted in the area of the holes. <IMAGE>

Description

SPECIFICATION Firing carriage including a rack structure of refractory material for the ceramics industry BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a firing carriage or kiln car to be used e.g. in fast firing tunnel kilns, including a rack structure of refractory ceramic material, in particular for temperatures above 10000 C., for the ceramics industry.The rack structure consists of refractory material composed of upright hollow posts which are inserted in corresponding recesses formed in the bottom of the carriage and in which posts, transverseiy extending holes or apertures are formed, continuous transverse beams are inserted through the transverse holes, continuous longitudinal beams are placed on the transverse beams, if desired, and firing bats are placed on the transverse beams or the longitudinal beams if provided. The rack structure provides support for articles such as plates and similar shallow articles during firing placed on the shelves or bats.

2. Description of the Prior Art the tubular posts or supports of such a firing carriage, also called kiln car (DE 31 23 896 Al, consist of a plurality of columnar sections which are interconnected co-axially. Connecting pieces which each are profiled at their one end and fit into each other in two positions offset by 1 800 with their opposite ends formed with a U-shaped recess, are inserted into upper and lower open ends of the columnar sections to form a horizontal aperture which receives horizontal transverse or longitudinal beams. The connecting pieces themselves are formed with plug-in type projections inserted into the interior of the front ends of the columnar sections.The connecting pieces also may be embodied by unitary structural members provided with diametral plug-in.type projections (German utility model 82 01 148) and formed with a horizontally oriented transverse hole or aperture, respectively, to be traversed by the firing beams or transverse carriers. The plug-in type projections provide a sliding form fit in the hollow end of the hollow columnar sections. Thus a convenient variable rack structure is formed. It is convenient for the connecting pieces to be made of a molded body having the same wall thickness also in the area of the plug-in type projections and being provided with reinforcements along the edges surrounding the plug-in openings or transverse hole. Sufficient stability is imparted to the rack structure by the connecting pieces being formed with continuous traversing openings.The sliding fit by which the plug-in type projections engage in the hollow columnar sections may be not particularly tight so that, on the whole, the rack structure may display a mobility which sometimes is undesired.

Rack structures for fast firing carriages comprising hollow posts are much easier and cheaper to build than rack structures having solid pillars. The hollow posts are adaptable in height to the respective requirements. By using especially high-grade temperature-resistant refractory materials, such as recrystallized silicon carbide, the supporting capacity of the rack structures may be made so high as to be comparable with racks including solid columns.

On the other hand, it is advantageous with the known racks that the firing bats are not supported by the posts on the firing bats of the respective next lower level.

Supporting frames for ths firing of ceramic articles, having continuous refractory posts and transverse holes are known per se (DE-AS 27 45 897). The transverse openings, though, in part are round and in part elongated and formed in solid columns to merely serve the purpose of saving weight. No beams of any kind are inserted through those apertures. Rather, the firing bats are placed on laterally protruding, particularly shaped projections.

SUMMARY OF THE INVENTION It is an object of the invention to provide a new and improved rack structure of a kiln car which will have the required rigidity and yet be producible inexpensively and particulalry easily for different requirements (2 to 4 levels). As before, each firing bat is to be loaded only by its own weight and the material received for firing.

According to this invention there is provided a firing carriage, including a rack structure of refractory ceramic material for use in the ceramics industry, the rack structure of refractory material comprising upright continuous hollow posts inserted in corresponding recesses formed in the bottom of the carriage, each of said posts being formed with apertures which extend in a transverse direction and in which apertures are provided, continuous transverse beams for supporting firing bats.

Surprisingly, it was found that sufficient rigidity and strength of the hollow posts can be obtained in spite of the transverse holes or apertures through the wall thereof, especially so if the posts are made rectangular or square in cross section.

Initially the hollow posts are manufactured in the usual way and then the transverse apertures are made. As it is convenient for all posts and beams to have at least a rectangular cross section, the transverse holes also are to be made rectangular.

Little clearance is needed between the longitudinal beams and the transverse holes, just enough to permit constraintless compensation of extension at the usual temperature variation.

In a preferred embodiment longitudinal beams are located on the transverse beams and the firing bats are located on top of the longitudinal beams.

It proved to be particularly convenient to increase the stability of the support of the longitudinal beams in the area of the transverse apertures by forming a transverse support in the hollow cavity of the post. In one embodiment the hollow posts each include an internal central wall which extends in the longitudinal direction of the posts, said wall being interrupted in the area of the transverse apertures, the median between the major surfaces of each wall being along the longitudinal axis of the respective transverse aperture, said wall thereby providing additional support for said transverse beam.In a further embodiment the hollow posts each include two internal, centrally disposed, fins which extend in the longitudinal direction of the posts and in the direction of the transverse beams, said fins being spaced from one another in the direction of the transverse beam and interrupted to permit passage therethrough of said transverse beam whereby said fins provide additional support for the transverse beam associated therewith. Such walls or fins constitute fu-rther support for the longitudinal beam, in continuation of the lower edge of the transverse aperture. On the other hand such a construction does not render the manufacture of the posts more difficult because, just like posts, the longitudinal beams may be produced in an extrusion process.When using fins, the additional consumption of material is small so that the hollow posts have a relatively small wall thickness and are of light weight.

An especially high breaking strength at very high temperatures is obtained if the posts and/or the longitudinal beams are made of cordierite ceramic material.

BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWINGS An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a side elevational view of the rack structure of a firing carriage, Figure 2 is a front elevational view of the firing carriage shown in Figure 1, and Figure 3 is a top plan view of the lowest rack surface through the left part of the rack structure as shown in Figure 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION In the figures, the firing carriage of the kind described in DE 31 23 896 Al, which is incorporated herein by reference but which is not completely herein illustrated, comprises a lower carriage including a wheel frame and a chassis with an upper rectangular bottom 1 in the upper surface of which plug-in sockets are formed to receive hollow posts 2. An upright hollow post 2 is provided near each of the four corners of the rectangular bottom 1.These hollow posts, which may have outer dimensions of e.g. 100 mm x 100 mm or 100 mm x 120 mm and a wall thickness of e.g. 1 5 mm, further comprise a central wall 3 (as shown in the lower part of Figure 3) or two spaced fins 3' (as shown in the upper part of Figure 3) which extends parallel to the narrow front end of the firing carriage, i.e. in the direction of the associated transverse beam, and may be, for example 40 mm wide.

The rack structure comprises a lower level 5, a central level 6, and an upper level 7. The lower level consists of supports 11 resting on the bottom 1, on which firing bats 12 are placed which have recesses for the hollow posts 2. The second level is formed by transverse beams 1 5 extending parallel to the front end of the firing carriage and by longitudinal beams 1 6 placed on the transverse beams, with further firing bats 12' placed on the longitudinal beams. The transverse beams 1 5 extend through respective transverse holes or apertures in the hollow posts 2 and the central wall 3 or fin 3' thereof and rest on the lower horizontal edge of the transverse aperture and the upper end face of the central wall 3 or fins 3' aligned with said edge.The longitudinal beams 1 6 are placed loosely on the transverse beams 1 5.

A connecting piece 20 is introduced with its downwardly protruding plug-in projection 21 in the upper end opening of the posts 2 - the central wall 3 or fins 3' being notched accordingly.

In its upper surface the connecting piece 20 is of U-shaped design forming a recess such that transverse beams 1 5 are inserted securely against any transverse slipping.

Instead of the connecting pieces 20 a complete transverse aperture -- as provided for the next lower level - or an upwardly open recess may be provided near the upper end of the post into which hole the transverse beams 1 5 are inserted or laid.

In this manner the posts 2 can be manufactured in greater length having transverse holes at regular spacings and can be severed, as required, in the area of a transverse hole (a short distance above or through the hole) so that the hole will be useful to hold a transverse beam 1 5. Again, longitudinal beams 1 6 may be placed on the upper transverse beams 1 5 and firing bats 12 placed on the longitudinal beams, even if the posts do project, a little (i.e. no more than corresponds to the thickness of the longitudinal beams) above the topmost transverse hole.

The posts 2 have a rectangular cross section, just like the transverse beams 1 5 and the longitudinal beams 1 6.

Claims

1. A firing carriage, including a rack structure of refractory ceramic material for use in the ceramics industry, the rack structure of refractory material comprising upright continuous hollow posts inserted in corresponding recesses formed in the bottom of the carriage, each of said posts being formed with apertures which extend in a transverse direction and in which apertures are provided, continuous transverse beams for supporting firing bats.

2. The firing carriage of Claim 1 wherein longitudinal beams are located on the transverse beams and the firing bats are located on top of the longitudinal beams.

3. The firing carriage as claimed in Claim 2, wherein the hollow posts each include an internal central wall which extends in the longitudinal direction of the posts, said wall being interrupted in the area of the transverse apertures, the median between the major surfaces of each wall being along the longitudinal axis of the respective transverse aperture, said wall thereby providing additional support for said transverse beam.

4. The firing carriage as claimed in Claim 2, wherein the hollow posts each include two internal, centrally disposed, fins which extend in the longitudinal direction of the posts and in the direction of the transverse beams, said fins being spaced from one another in the direction of the transverse beam and interrupted to permit passage therethrough of said transverse beam whereby said fins provide additional support for the transverse beam associated therewith.

5. The firing carriage as claimed in any preceding claim, wherein the posts and beams are rectangular in cross section

6. The firing carriage as claimed in any preceding claim, wherein the posts and/or transverse beams and/or longitudinal beams are made of cordierite refractory material.

7. A firing carriage substantially as herein described with reference to and as shown in the accompanying drawings.