US2297286A - Sagger - Google Patents

Description

A. R. BOO

Sept 1942.

SAGGER Filed Jan. 30, 1940 NVENTO WI w J r 1 ..|.J f R L i T 1 o Patented Sept. 29, 1942 UNlTED STATES PATENT OFFICE 2 Claims.

This invention pertains to saggers and is for a sagger of composite construction.

In the burning or firing of ceramic objects, it

is customary to place the green or unfired ware in refractory receptacles which are known as saggers. These saggers, after being charged with the ware, are introduced into the furnace wherethe ware is ,fired. The saggers can be piled one :upon another to any desired height and they prevent the articles which are to be fired from being crushed or from cominginto contact with one another.

Saggers as heretofore usually constructed are molded and formed as a single refractory body with a bottom and side walls. Because of such structures being formed in one piece, they cannot relieve themselves of strains which may be set up in them with the result that when they are in use they frequently warp or buckle or even break and are thus rendered unfit for further use. Moreover, if any part of the sagger breaks or is broken, the whole structure'is destroyed as it is not practical to :repair them.

I have discovered that by forming the sag er as a composite structure, it is free of many of the strains which exist in a sag-ger formed as an integral structure so that the composite saggers of my invention will normally considerably outlast saggers as heretofore constructed. Moreover, the composite structure made in accordance with the present invention may provide limited relative movement between the parts which allows the structure to adjust itself to strains which may be set up in it when it isbeing heated or cooled and-whereby one part may move relative to another'as expansion or contraction or warping takes place. Furthermore, the present invention provides a sagger in which various parts may be replaced if they become :broken .so that the entire structure does not have to be discarded in the event one part breaks. By reason of this same fact, corresponding parts .of different saggers may be interchangeably used. All of these advantages decrease the cost of saggers to the'manufacturer of ceramic articles even though individual saggers embodying the present invention may be slightly more expensive initially than the saggers heretofore generally provided.

My invention further provides a sagger construction in which means is provided for supporting a removable tray intermediate the top and bottom of the sagger so that a sagger of standard height may be interchangeably used either for the burning .of a single layer of rela- Cir tively high pieces or plural layers of smaller pieces.

My invention may be readily understood by reference to the accompanying drawing in which Figure l is a top plan view of a sagger embodying my invention, the sagger being shown as having an intermediate tray therein, one corner of the figure being broken away to show a section through the corner construction at a point below the tray;

Figure 2 is a transverse vertical section in the plane of line IIII of Figure 1;

Figure 3 is a perspective view of one of the corner posts;

Figure 4 is a fragmentary View showing a vertical section through a slightly modified construction.

In the drawing the sagger is illustrated'as being of a generally rectangular shape. It is comprised of a unitary fiat bottom tile 2 of rectangular shape. Secured to the bottom tile 2 at each corner thereof is a corner post 3. These corner posts one of which is shown in the perspective view in Figure '3, may be provided with a fiat lower end which sets on the top of the tile 2 and the post is secured to the tile by a suitable refractory cement. Each post is provided with two vertically extending grooves 4 and 5 in two side walls thereof, these grooves being in two faces which are at right angles to each other and extend from the top to the bottom of the post. The upper part of the post shown in Figures 1, 2 and 3 is square in cross section, but the inner corner of each post is shown as being provided with an offset portion 6 that extends from the bottom of the post to a point intermediate the topand the bottom, this offset providing a shoulder 1 on the corner post intermediate the top and bottom thereof.

The grooves 4 in the corner posts serve to receive the ends of longitudinally extending side forming tiles 8. These tiles comprise flat slabs of refractory material of appropriate width and thickness. Preferably the slabs 8 are of a width slightly less than the height of the corner posts 3 so that when these slabs are slipped into position in the corner posts by dropping them in from the top of the posts, the uppermost edges of the slabs 8will be below the top of the posts as best shown in Figure 2. Likewise, the grooves 5 in the corner posts serve t receive the ends of transversely extending tiles 9 that form the end walls of the sag-ger. The tiles or slabs 9 are preferably of the same width as the slabs or tiles 8 so that the top of these slabs is also below the top of the corner posts.

The grooves 4 and 5 and the slabs 8 and 9 are preferably so dimensioned that the ends of the slabs are quite loosely received in the grooves 4 and 5 so that the tiles 8 and 9 may be easily slipped into place without straining or binding and so that there is adequate clearance in all directions to allow for expansion or contraction of one part relatively to another or for any relative movement that may occur by reason of one part warping or bending slightly with respect to another.

The sagger is illustrated as having a removable tray l0 therein. This tray comprises a onepiece slab of tile or refractory material having notched-out corners II. These cut-out corners II enable the corners of the tray ID to clear the upper portions of the corner posts 3, but the shoulders I at the top of the offset portions 6 on the corner posts will support the tray l0 intermediate the top and the bottom of the sagger. The tray I0 is also preferably provided with finger notches l2 along each longitudinal edge thereof to facilitate the removal of the tray from the sagger,

Each part of the sagger is formed separately from every other part. The various parts comprising the sagger may be shipped by the manufacturer of the sagger to the user in a knockeddown or unassembled form. This considerably facilitates the packing of the saggers for shipment, conserves space in shipping, and reduces loss through breakage in transit. The user of the sagger assembles it by cementing the corner posts to the bottom tile and after the cement has set, the side and end tiles 8 and 9 are slipped into place and the sagger is ready for use.

Because of the fact that each of the parts of the sagger is manufactured separately or is a separate entity and since each part is a relatively simple shape, the structure is free of the internal strains and stresses that are usually present in a sagger in which the bottom and side walls are integral. Likewise, because of the fact that the side walls and end walls are separate from each other and freedom for relative movement is provided at the corner posts, any strains set up in the side or end walls or any relative movement in a side or end wall member are not transmitted to the other members. Since the side and end walls merely rest on the bottom tile, any slight warping or buckling of the bottom tile will not disrupt or strain the side or end walls. If at any time any of the side or end walls or corner posts becomes broken, it can be replaced without completely replacing all of the parts of the sagger, and if a bottom tile breaks or becomes non-usable, the remaining parts may be salvaged for use in another sagger.

The construction is of advantage to the manufacturer of the sagger in that loss through breakage in manufacture is considerably less in the making of the composite parts of the sagger than where the sagger is formed as an integral structure. Economy is secured through the advantages of the composite sagger in shipping. The sagger is of advantage to the used because while the initial cost may be slightly higher, the destruction through use is very considerably less and by reason of the fact that one part can be replaced without replacing the entire sagger, a very considerable saving inures to the user. It has been demonstrated that the present invention materially reduces the sagger cost to a user.

Because of the longer life of the sagger and because of the fact that parts may be replaced, the manufacturer is justified in using better materials and the additional cost of such better materials is justified through the greater economy that the user secures. The materials preferably employed are bonded silicon carbide refractory.

While the corner posts 3 may merely be cemented to the bottom tile 2, it may be desirable to facilitate the accurate positioning of the corner posts and to secure a better joint to have some interfitting engagement between the bottom tile and the corner posts. One such mechanical interfitting arrangement is illustrated in Figure 4 where the corner post 3 is provided with a pinlike extension or dowel 3 on the bottom thereof which extension passes through a hole 2' in the bottom tile 2. This merely illustrates any one of a number of different interlocking or interfitting engagements that may be provided between the corner post and the bottom tile.

A further advantage is gained in the present invention by having the side and end walls terminate below the tops of the corner posts. In the ordinary use of saggers, they are piled one on top of another. By having the corner posts extend above the side walls, the weight of a superimposed sagger will be transmitted through the corner posts which are of adequate cross section to carry the load, and the load of the superimposed sagger or saggers is not carried on the side and end walls.

Through the provision of means such as the offset 6 on the corner posts 3, it is possible to use an intermediate tray without the use of other spacing means inside the sagger. A sagger of standard height may, therefore, be readily used for the burning of two layers of small objects or the burning of a single layer of higher objects.

It will be understood that all of the parts of the sagger are made of a ceramic refractory composition and as above mentioned, this is preferably a composition containing silicon carbide, although the invention is not confined to any particular refractory. The bottom tile 2 is made of a thickness and strength such that it provides a rigid tray forming the main body of the sagger since the side and end walls, being unconnected with the corner posts, do not in themselves form any rigid frame.

While I have illustrated and described certain specific embodiments of my invention, it will be understood that the invention is not limited to the particular constructions herein described and illustrated but may be otherwise constructed and embodied within the contemplation of my invention and under the scope of the following claims.

I claim:

1. A composite sagger comprising a one-piece bottom tile'of refractory composition, a plurality of refractory corner post members secured to the bottom tile, a plurality of separate side wall tile members of refractory material resting edgewise on the bottom tile and having a loose interfittlng engagement with the corner posts the corner post members and the side wall members forming a complete enclosure around the edge of the bottom tile, the sagger being open at its top, a horizontal tray within the sagger of a dimension such that it may be introduced through the open top of the sagger, and means on some of said members for supporting the tray in spaced relation to the bottom tile and below the upper edges of the side wall tiles.

grooves in the corner posts, said slabs forming 10 the side walls of the sagger and extending around the bottom tile to form a complete side wall enclosure, said corner posts each having a horizontal shoulder formed thereon intermediate the top and bottom thereof on that portion of the post which lies between two intersecting side wall tiles,

, and a removable refractory tray resting on said shoulders.

AUSTIN R. BOOK.

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