US3463865A - Refractory block for annular linings - Google Patents

Description

Aug. 26, 1969 E. M. SARRAF' 3,463,365

REFRACTORY BLOCK FOR ANNULAR LININGS Filed Jan. 5, 1967 I5 5 Fig. 2

' //Vl E/V7'A. 3 [an/4P0 M SAP/84F A TTOR/VE) United States Patent 3,463,865 REFRACTORY ,BLOCKFOR ANNULAR LININGS Edward M. Sarraf, 22290 Blossom Drive, Rocky River, Ohio 44116 Filed Jan. 3, 1967, Ser. No. 606,944 Int. Cl. Hk 5/12, 5/02 US. Cl. 13-35 2 Claims ABSTRACT OF THE DISCLOSURE Refractory linings for barrel type channel furnace induction furnaces and other vessels having an annular refractory lining. The shapes are characterized as having generally opposed curved side surfaces, opposed end surfaces and opposed face surfaces. The shapes contain complementary tongues and grooves in opposed face surfaces extending between the opposed side surfaces and also between the opposed end surfaces.

The shapes of the present invention are primarily designed for use in barrel type channel induction furnaces where the problem is most acute. Channel induction furnaces are used throughout the ferrous and nonferrous metals industries for melting and holding hot metals. They are used primarily in foundries because of the close temperature control they provide and the need for such control in foundry casting. Furthermore, they are extremely economical as their electrical efficiencies approach 97%; and, among other advantages, they operate directly from standard frequency power lines.

The basic design for most channel induction furnaces is a hearth for holding the hot metal and at least one inductor block. The hearth of a barrel type inductor furnace generally has a cylindrical wall and two end walls perpendicular to the cylindrical axis about which the whole furnace rotates. On the cylindrical wall, there is at least one door for charging scrap and removing slag. Generally opposite the charging door in the cylindrical wall, there is at least one openingor throat. The inductor blocks are releasably attached to the cylindrical wall in communication with the throat. Regardless of how many inductor blocks and charging doors are used, at least one charging door and one inductor block are positioned so that hot metal can be poured directly into an inductor block. This is necessary to start up a cold furnace. Spouts for charging and removing hot metals are usually joined to the end walls of the hearth. The walls of the hearth consist of an outer metal shell which is lined with refractory brick and monolithic materials.

In all furnaces of which I am aware, the inductor block linings receive severe wear. This is because the temperatures are higher in the inductor blocks than elsewhere, and metal is continuously drawn through the restricted inductor channel tending to erode or wash away refractory surfaces. For this reason, inductor blocks are releasably attached to the hearth so they can periodically be removed and relined.

In the hearth of an induction furnace there are several severe wear areas. The area adjoining the inductor blocks referred to as throats, are often consumed before the rest of the hearth for the same reasons the inductor blocks are rapidly consumed. Another reason for deterioration of the throat area is the difficulty in providing a structurally integral refractory lining adjacent the throats to hold them securely in place.

According to this invention, it is possible to line a large barrel type induction furnace with brick such that, as the throat area is worn away or periodically replaced, the rest of the lining remains snugly in place.

Therefore, it is an object of the present invention to 3,463,865 Patented Aug. 26, 1969 provide a structurally integral arcuate refractory lining for barrel type induction furnaces and the like.

According to one aspect of this invention, a refractory lining is provided for a barrel type channel induction furnace having a generally cylindrical metal shell, and two end walls, at least one opening in the shell for charging, and at least one throat opening through an inductor block generally opposite the charging door. The lining is composed of a plurality of adjacent annular courses of refractory brick having opposed face surfaces transverse to the shell, opposed end surfaces and opposed side surfaces. The opposed side surfaces are also referred to as the hot face and cold face, the cold face being adjacent the metal shell and the hot face open to the interior of the furnace. The end faces are joined to adjacent brick in each course. The refractory brick contain complementary tongues and grooves in the face surfaces extending between opposed side surfaces. It is preferred that the brick also contain complementary tongues and grooves in opposed face surfaces extending between the opposed end surfaces. The brick are arranged so that the tongues and grooves are complementarily mated with the brick in "adjacent courses to provide a continuous tongue and groove joint concentric with the metal shell and also one transverse to the metal shell.

Further features and other objects and advantages of this invention will become clear to those skilled in the art by the study of the following detailed description with reference to the drawings in which:

FIGS. 1 and 2 are an isometric view of the novel shapes employed in the present invention: and

FIG. 3 is a cross sectional view of the hearth of a barrel type channel induction furnace.

Referring to the drawings, the hearth of the barrel type induction furnace is contained in an outer metal shell 1 which is generally cylindrical. Adjacent the other metal shell is a refractory lining 3. The lining maybe divided into a separate insulating lining and a working lining if desired. There is a charging door (not shown) and slag removing door (not shown) located in the cylindrical wall of the hearth. There is a throat 5 generally opposite the charging door. As shown in FIG. 3, the working lining 3 is lined with the refractory shapes 5 of this invention. The shape 5 may be used in each course of the annular lining and are keyed or tightened together with wedge shape brick 7. For details on the design of a typical barrel shaped channel induction furnace, attention is directed to United States patent application, Ser. No. 572,563.

The shapes used in the lining of the induction furnace are shown in FIGS. 1 and 2. The shape 5 consists of opposed end surfaces 9' and 11, opposed curved side surfaces 13 and 15 and opposed face surfaces 17 and 19. One of the face surfaces 17 contains a plurality of tongues 21 extending between the side surfaces and a plurality of tongues 23 extending between the end surfaces. The other opposed face 19 contains a plurality of complementary grooves 25 extending between the opposed side surfaces and a plurality of complementary grooves 27 extending between the opposed end surfaces. The tongues and grooves on the faces of the brick are complementarily mated with the tongues and grooves of adjacent brick along the annulus of the kiln to provide an integral and unitary lining. Further, to insure the interlocking of the brick along the annulus and to prevent their displacement by the force of gravity, the joints in each course of brick are staggered with respect to an adjacent course.

It is intended that the foregoing descriptions and drawings be construed as illustrative and not in limitation of the invention.

Having thus described the invention in detail and with suificient particularity as to enable those skilled in the art to practice it, what is desired to have protected by Letters Patent is set forth in the following claims.

-I claim:

1. A rotatably mounted barrel shaped channel induction furnace comprising a generally cylindrical metal shell closed by end Walls, a refractory lining adjacent the shell, said lining composed of a plurality of adjacent courses of refractory brick having generally opposed curved side surfaces, and opposed ends extending between a pair of opposed face surfaces, said face surface of each brick being provided with complementary tongues and grooves extending between opposed side surfaces, said face surface of each brick being provided with at least one complementary tongue and groove extending between opposed end surfaces, said brick being disposed so that a side surface is adjacent the metal shell and the tongues and grooves are complementarily mated with 4 brick in adjacent courses to provide an integral lining. 2. An induction furnace according to claim l in which each brick course contains a plurality of joints which are staggered with respect to an adjacent course.

References Cited V UNITED STATES PATENTS BERNARD A. GILHEANY, Primary Examiner 15 R. N. ENVALL, JR., Assistant Examiner US. Cl. X.R. 266-43

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