EP0208249B1

EP0208249B1 - Kiln cars

Info

Publication number: EP0208249B1
Application number: EP19860108992
Authority: EP
Inventors: John Elliott
Original assignee: Acme Marls Ltd
Current assignee: Acme Marls Ltd
Priority date: 1985-07-05
Filing date: 1986-07-02
Publication date: 1989-09-27
Also published as: CN1017183B; DE3665929D1; GB8517172D0; EP0208249A1; CN86105634A; GB2179127A

Description

This invention relates to kiln cars of the type employed for carrying articles of ceramic ware through a kiln during a firing process. Such kiln cars normally comprise a non-refractory trolley which supports a refractory structure including at least a base which protects the trolley and carries the ware to be fired, the latter often being supported on a refractory superstructure which is built up on the base.
To reduce loss of heat due to thermal cycling, it is desirable to minimise the thermal mass of the base, for example as described in our European Patent specification No. 0024037.
To facilitate mechanical loading of ware to be fired, it has been proposed to use a superstructure which is adapted to carry removable shelves, known as bats, on which the ware is placed priorto assembly of the loaded shelf with the superstructure. However, to ensure the necessary degree of stability for the superstructure, both when the ware-carrying shelves are in place and when they are absent, it has been found necessary to incorporate into the superstructure transverse members which interconnect vertical members which afford supports for the removable shelves.
In one arrangement, as described in our U.K. Patent specification No. 1518052 for example, the superstructure incorporates a vertical wall running along the longitudinal centre line of the kiln car. Vertical members are secured-to such central wall at spaced longitudinal intervals and extend outwardly in mutually parallel relation to define bays forthe reception of removable shelves on supporting ledges carried by the vertical members. This arrangement has the disadvantage that the central wall divides the car into two lateral zones, so that loading of the bats has to be carried out from opposite sides of the kiln car. Where mechanised loading is employed, this requires the use of either two sets of loading apparatus, or specially designed loading apparatus which can serve both sides of the kiln car either simultaneously or in sequence. However, such apparatus is undesirably costly and may often be too bulkyfor practical use.
In another arrangement, as described in U.K. Patent 1421504 for example, the superstructure includes superposed column elements which are interconnected by fixed horizontal shelves and also afford vertically spaced supports for additional, removable shelves. Whilst this arrangement is such that loading may be carried out from only one side of the kiln car, it is not well suited to mechanical loading since the fixed shelves cannot effectively be utilised to support ware, unless hand-loaded. Additionally, the minium clearance which must be available beneath a removable shelf in order to accommodate supporting parts of the loading mechanism causes a relatively large volume of space above such fixed shelves to be unused, thereby significantly reducing the load carrying capacity of the refractory superstructure.
Both of these examples suffer from the further disadvantage that the superstructure is of relatively massive construction, and hence gives rise to significant energy loss due to thermal cycling.
The object of the invention is to provide a refractory structure for a kiln car which affords an improvement over such prior proposals in one or more respects, the invention being given in claims 1 to 13.
In accordance with the invention, a refractory structure for a kiln car may include one or more of the following features:-

(a) a superstructure for carrying removable ware-carrying shelves comprising a plurality of columns of refractory material each affording vertically spaced support members for said shelves, the lower ends of the columns being located in respective apertures which extend through a refractory base for substantially the whole thickness thereof;
(b) a superstructure for carrying removable ware-carrying shelves comprising only a plurality of columns of refractory material each affording vertically spaced support members for said shelves with means connecting said columns together only at their upper ends;
(c) a superstructure for carrying removable ware-carrying shelves comprising a plurality of columns each formed by an upright inner member of refractory material and a plurality of sleeves or collars of refractory material received on said inner member in end-to-end relation;
(d) a refractory base of hollow construction filled with lightweight refractory material of low thermal mass and incorporating a plurality of socket members which extend over substantially the entire thickness of the base and afford respective apertures for the reception of the lower end of a corresponding upright member of refractory material forming part of a superstructure for carrying removable ware-carrying shelves;
(e) socket members which extend over substantially the entire thickness of a refractory base of hollow construction filled with lightweight material of low thermal mass for the reception of upright members forming part of a superstructure, the socket members being secured in the base by means of fixed upright posts which enter into further apertures adjacent to the apertures which receive said upright members;

These and other features of the invention will now be described by way of example with reference to the accompanying drawings wherein:-

FIGURE 1 shows a refractory superstructure for a kiln car in accordance with the invention, partly in side elevation and partly in longitudinal section;
FIGURE 2 shows a corresponding end view; and
FIGURE 3 shows a part-sectional plan view on the line III-III of Figure 1, with the omission of the removable shelves and insulation in the interior of the base hereinafter described.

As shown in the accompanying drawing, a preferred embodiment of ware-supporting refractory structure for a kiln car comprises a hollow refractory base 10 which supports a refractory superstructure 30 adapted to carry a plurality of removable rectangular ware-carrying bats or shelves 50.
The base 10 is of rectangular form and incorporates refractory socket members 11 at the corners, together with further socket members 12 intermediate the corners, and two additional socket members 13 arranged on the longitudinal centre line of the base. The socket members are carried by three longitudinally extending metal straps 14, each having four upright, tubular metal posts 15 secured thereto. The posts 15 enter into respective apertures 16, 16a of corresponding sectional shape which preferably extend through the entire height of the socket members from end-to-end thereof as shown. As shown, the posts 15 and apertures 16, 16a are most conveniently of square shape in cross-section, as are the socket members 11, 12 and 13, although other appropriate shapes could be employed.
The socket members are formed with vertically extending external grooves 17 which serve to locate the edges of pairs of refractory panels 18 and 19 which collectively form the lateral walls of the base 10. An outwardly extending baffle 20 is formed by laterally projecting refractory plates which are assembled between the panels 18 and 19 for the purpose of obstructing the transmission of radiant energy downwardly from the interior of the kiln around the outside of the base towards a metal trolley (not shown) on which the refractory structure is carried through the kiln.
The interior of the base 10 is filled with insulating blocks 21 covered by a layer of insulating material 22, so that the whole construction is of relatively light weight and low thermal mass.
It is particularly important to note that the socket members 11,12 and 13 extend over substantially the entire thickness of the base 10. At their upper ends, the socket members support a plurality of cover plates 23 which close the top of the base.
It should also be noted that the posts 15 extend upwardly from the lower end of each socket member 11, 12, 13 over a major part of its height so as to locate the socket members not only against lateral movement, but also effectively to restrain them from rocking about their lower ends.
As can be seen, the apertures 16, 16a are not positioned centrally of the square section socket members, but in the case of the corner socket members 11 the apertures 16 are offset towards one corner of the member, whilst in the case of the side socket members 12, and the central socket members 13, the apertures 16a are offset towards one side. This arrangement enables each socket memberto afford a further similar aperture 24, 25 which extends parallel to the aperture 16, 16a respectively through substantially the full height of the socket member, and hence throughout substantially the full thickness of the base 10.
Preferably, the corner socket members 11 are formed with open-ended through-apertures 24 arranged in the corners of the socket members diagonally opposed to the corners at which the apertures 16 are formed, whilst the side and central socket members 11 and 12 are formed with open-ended through-apertures 25 which are arranged adjacent to the side of the members opposite to that at which the apertures 16a are formed. The apertures 24 and 25 are conveniently of square shape in section, although other sectional shapes could be employed.
As can be seen from Figure 3, the socket members 11 and 12 are assembled on the straps 14 in such a way that the through- apertures 24 and 25 are disposed outwardly of the corresponding posts 15 on which the socket members are located. In this way the through apertures 24 and 25 are as close as possible to the corners and outer edges of the base 10 respectively.
Each aperture 24, 25 receives the lower end portion of a column 31 forming part of the superstructure 30. The columns 31 may be of one- piece construction, but in the illustrated embodiment in accordance with a preferred feature of the invention they are of composite construction, including a substantially full-height inner member 32 which is conveniently formed as a length of thick-walled square section ceramic tube of dimensions adapted to fit closely within the apertures 24, 25. In this way, the lower end of each inner member 32 rests on the metal straps 14 and is supported by the corresponding socket member 11, 12, 13 over a length corresponding substantially to the entire thickness of the base 10' so as to provide maximum support.
The inner members 32 in the illustrated embodiment each carry a plurality of superposed outer members, as illustrated comprising alternate spacers in the form of sleeves 33 and shelf support members in the form of collars 34. The sleeves each consist of lengths of square section ceramic tube, whilst the collars 34 are of generally plate-like form with a square aperture to receive the inner member 32. As can be seen most clearly in Figure 1, the collars 34 project laterally relative to the ends of the sleeves 33 so as to afford lugs 39 on which the shelves 50 may be supported. Most conveniently, the collars 34 are of generally rectangular shape in plan view, although other shapes could be adopted.
Whilst in the described embodiment the lugs 39 are afforded by collars 34 which are structurally separate from the sleeves 33, it will be appreciated that the sleeves could be formed with integral lugs so that no separate collars would then be required. Likewise, whilst in the illustrated embodiment the lugs are separate from the inner member 32, it will be appreciated that the columns 31 could have the lugs integrally formed thereon so that neither the sleeves nor the collars are required.
In order to stabilise the columns 31 without obstructing the space between them, the columns are connected together above the base 10, but only at their upper ends. Top plates 38 are assembled in such a manner as to hold the columns against relative lateral movement. In the illustrated embodiment each column carries a respective top member which incorporates one or more upstanding projections which enter into corresponding recesses formed at the underside of the top plates 38.
In the embodiment illustrated, the columns 31 at the corners of the superstructure carry top members 35 including a single projection 35a which engages in a corresponding recess at the corner of the top plate supported by the corner column. The columns 31 intermediate the corners carry top members 36 which include a pair of projections 36a arranged to engage in recesses afforded at adjacent corners of the two adjoining top plates supported by such columns. Similarly, the two central columns 31 carry top members 37 which afford four projections (not shown) to engage in respective recesses at the adjacent corners of the four adjoining top plates supported by those columns.
Whilst the top members 35, 36, 37 could, like the collars 34, be formed with square apertures to locate on the inner member 32 of the column 31, in a preferred arrangement the inner member 32, whilst extending over substantially the full height of the assembly of sleeves and collars, terminates at its upper end at a position spaced slightly below the upper end of the uppermost sleeve 33 so that the latter affords a shallow socket for the reception of a square-shaped projection 35b, 36b, 37b at the underside of the corresponding top member. Alternatively, the top member could be formed with a smaller downward projection adapted to enter the end of the inner member 32, when the latter is of tubular form, although the inner member could be made from solid rod if required.
It will be appreciated that the removable shelves 50 can be placed in position on the lugs 39 afforded by the collars 34 from either side of the superstructure since there is no obstruction to prevent such a shelf being passed from one side of the superstructure to the other. Each removable shelf 50 may extend across the full width of the superstructure so as to be supported at its four corners and mid-way along its longer sides. Alternatively, each shelf may extend across only half of the width of the superstructure, in that case each shelf being supported adjacent to its corners by four lugs carried by respective columns 31. However, if it is desired to provide three-point support for such shelves it would be possible to modify the base 10 so that the central strap 14 provides support for only three columns, at positions aligned centrally between the pairs of columns supported by the outermost straps 14. In this way, each removable shelf 50 would be supported by three lugs, although in this case the shelves could not be passed through the superstructure from one side to the other. Whilst this would hinder the mechanical loading of the shelves for the reasons previously given it may nevertheless be useful in some circumstances. It is particularly to be noted that, contrary to previous practice, the lower ends of the columns 31 do not require to be embedded in massive supports. By contrast, the socket members 11, 12, 13 which give the required support for the columns are comparatively light in weight, and this is made possible by the fact that they are formed with two apertures, one for locating the socket member in a fixed position on the corresponding strap 14, and one for receiving the lower end of the column 31. Since these two apertures extend parallel to one another, the members received therein can extend through substantially the full height of the socket member and thereby maximise the support which is provided within the vertical dimensions of the base.
Forming the columns 31 by assembling sleeves 33 and collars 34 on the inner member 32 has the advantage that the sleeves can readily be formed to various lengths so as to enable the superstructure 30 to be adapted to support removable shelves 50 at varying spacings according to the requirements of the ware being fired.
As will be apparent the superstructure 30 is itself of relatively lightweight construction so as to minimise energy loss due to thermal cycling and yet the structure is stable enough to enable the removable shelves 50 to be loaded mechanically.

Claims

1. A refractory structure for a kiln car comprising a refractory base (10) for mounting on a trolley and a refractory superstructure for carry- . ing removable ware-carrying shelves wherein said superstructure (30) comprises a plurality of columns (31) of refractory material, each affording vertically spaced support means (39) for receiving said shelves (50), the lower ends of the columns (31) being located with said base (10), characterised in that said base (10) incorporates respective socket members (11, 12, 13) of refractory material which extend through said refractory base (10) for substantially the entire thickness thereof for the reception of lower end portions of said columns (31), each of said socket members (11, 12, 13) affording a first aperture (24, 25) in which the lower end portion of one of said columns (31) is received and a second aperture (16, 16a) which receives a respective fixed upright post (15) whereby said socket member (11, 12, 13) is located within said base (10).

2. A refractory structure according to Claim 1 wherein said first apertures (24, 25) for the reception of the lower end portions of the columns (31) and said second apertures (16, 16a) which receive the posts (15) extend alongside one another in each socket member (11, 12, 13) and throughout substantially the entire height of the socket member.

3. A refractory structure according to Claim 2 wherein said socket members (11) are provided at the corners of the base brackets (10) and in said corners the first apertures (24) for the reception of the lower end portions (32) of the columns (31) are disposed diagonally outwardly offset from the second apertures (16) in which the posts (15) are received.

4. A refractory structure according to Claim 2 or Claim 3 wherein said socket members (12) are provided at intermediate positions along the sides of the base (10) and at such side positions the first apertures (25) for the reception of the lower end portions (32) of the columns (31) are disposed outwardly offset from the first apertures (16a) in which the posts (15) are received.

5. A refractory structure according to any one of Claims 1 to 4 wherein such socket members (11) are provided at the corners of the structure and in said corner socket members (11) the apertures (24) for the reception of the lower end portions (32) of the columns (31) are disposed diagonally outwardly offset from the apertures (16) in which the posts (15) are received.

6. A refractory structure according to Claim 4 or Claim 5 wherein such socket members (12) are provided at intermediate positions along the sides of the structure and in said side socket members (12) the apertures (25) for the reception of the lower bed portions (32) of the columns (31) are disposed outwardly offset from the apertures (16a) in which the posts (15) are received.

7. A refractory structure according to Claims 4 to 6 wherein the posts (15) are carried by metal strips (14) at the underside of the base (10) and the lower ends of the columns (31) rest on said strips (14).

8. A refractory structure according to any one of Claims 1 to 7 wherein the base (10) is of hollow construction comprising side plates (18,19) and cover plates (23) and is filled with lightweight refractory material (21, 22) of low thermal mass.

9. A refractory structure according to any one of Claims 1 to 8 wherein said columns (31) are each formed by an upright inner member (32) of refractory material and a plurality of superposed outer members (33, 34) of refractory material received on said inner member (32) in end-to-end relation and affording said support means (39) for the shelves (50).

10. A refractory structure according to Claim 9 wherein said outer members comprise alternate spacer members (33) and support members (34) which afford said support means (39) for said shelves (50).

11. A refractory structure according to any one of Claims 1 to 10 wherein said columns (31) are connected together above the base (10) only at their upper ends.

12. A refractory structure according to Claim 11 wherein said columns (31) are connected together by means of top plates (38).

13. A refractory structure according to Claim 12 wherein each of said top plates (38) incorporates recesses at the corners thereof and each of the columns (31) carries at its upper end a respective top member (35, 36, 37) respectively affording projections (35a, 36a, 37a) adapted to enter into the recesses at the corners of the top plates (38).