US 3563523 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
United States Patent  lnventor John S. Wendt,Jr.
Sewiekley,Pa.  AppLNo. 755,138  Filed Aug. 26, 1968  Patented Feb. 16, 1971  Assignee Dravo Corporation Pittsburgh,Pa.
 LINING APPARATUS 10 Claims, 4 Drawing Figs.
 U.S.Cl. 266/42, 25/14. 25/36; 264/30; 266/]  lnt.Cl. C21b7/l2  Fieldot'Search ..266/42,43, (lnquired); 264/30, (lnquired); 18/( Patch digest); 25/14, 18, 36,41 (J), (Inquired)  References Cited UNITED STATES PATENTS 478,279 7/1892 Gardiner 25/14 518,169 4/1894 Williams 25/14 1,117,466 l1/l9l4 Wewerka 25/36 1,780,485 11/1930 Hopkinsetal... 266/42 1,858,956 5/1932 l-lepperle 25/14 1,926,415 9/1933 Wertz 18/1 Primary Examiner-Gerald A. Dost Attorney-Parmelee, Utzler and Welsh ABSTRACT: An apparatus for relining metallurgical furnace tap-holes is disclosed. The apparatus is adapted to be inserted in a furnace tap-hole and includes a tubular housing, a supply hopper communicating with the housing for introducing a lining material into the housing and a screw conveyor for advancing the lining material from the hopper forwardly through the housing. The forward end of the housing is closed by a nose piece and the housing has openings around its periphery to the rear of the nose piece. A discharge member is provided within the housing between the forward end of the screw conveyor and the nose piece and generally in the transverse plane of the openings for forcing material radially through the openings. Means are provided for driving the screw conveyor and simultaneously imparting a vibratory motion to the housing so that as lining material is discharged through the openings, the housings outer wall compacts the lining materia1 against the inner wall of the tap-hole.
LIN ING APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to lining apparatus and more particularly to an apparatus designed for use in relining the tap-hole of a cupola furnace. The apparatus may also be used for applying a lining in other furnaces or in some other object such, for example, as applying a cementitious composition or a plastic lining of some character to the interior of a pipe.
2. Description of the Prior Art A furnace tap-hole must be lined with some refractory material that will set hard and tend to resist the eroding effect of liquid metal or slag when the hole is tapped and molten material flows from the the tap-hole to the runner-trough.
A cupola furnace generally has a single tap-hole through which both molten metal and slag are discharged from the furnace. Consequently, the erosion of the lining is much more rapid than with most metallurgical furnaces where the refractory can be selected for one molten liquid and not different reactive liquids such as molten iron and molten slag.
Generally, a tap-hole is formed in a cupola furnace by first placing a forming pipe or insert in-an opening left in the brick work of the furnace and into the space between the forming pipe or insert and the brick work there is rammed a refractory material and binder therefor. The forming pipe or insert is then removed leaving the tap-hole. Before the furnace is charged, the tap-hole is generally plugged or filled in with clay or some other material by means of a clay or mud gun and at the completion of each furnace casting operation or whenever else desired, the tap-hole is tapped or unplugged by punching a hole through the plugging material with a rod. in use the taphole is deteriorated until it has to be relined and the process heretofore described to initially form the tap-hole must be repeated.
Briefly, the present invention provides an apparatus for relining a furnace tap-hole and comprises a screw conveyor mounted on a shaft and carried in a tubular housing, The housing is adapted to be inserted into an enlarged and deteriorated tap-hole and its outside diameter is such that when it is inserted into the opening there is more or less clearance between it and the eroded walls. The housing is fitted at its forward end with a nose piece that'closes the forward end of the housing and provides a forward support or bearing for the screw conveyor. At the rear end of the housing there is provided a hopper communicating with the housing into which a plastic refractory mix for relining the tap-hole is charged. The hopper feeds the lining material into the screw conveyor which advances it to the forward end of the housing. Openings are formed in the housing rearwardly of the nose piece and discharge means are carried on the forward end of the conveyor screw confronting the openings for forcing material radially through the openings. Means are provided for rotating the conveyor shaft and simultaneously imparting a vibratory motion to the housing. As the plastic refractory lining material is discharged through the peripheral openings, it fills the void between the tubular housing and the wall of the tap-hole and due to the vibratory action, the outer wall of the housing compacts the lining material against the inner wall of the tap-hole. Progressively withdrawing the housing from the tap-hole, approximately 2 or 3 inches at a time, permits additional material to be forced into the annular void and be compacted against the inner wall of the tap-hole.
Other advantages and capabilities of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a partial diagrammatic vertical cross section through the tap-hole of a furnace;
FIG. 2 is a view in side elevation and partial section of a lining apparatus according to the present invention;
FIG. 3 is a fragmentary, longitudinal sectional view on an enlarged scale of the lining apparatus of FIG. 2; and
FIG. 4 is a transverse sectional view taken along the line lV-IV of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings wherein like reference numerals refer to like parts throughout the several views, 10 designates a portion of a furnace wall such as the wall of a eupola. The wall 10 is of usual and well-known construction and has the usual tap-hole 12 which opens into a runner-trough 14.
The apparatus for relining the tap-hole 12 is shown in FIG. 2 generally at 16. The apparatus 16 includes a supply hopper 18 for receiving a material such as a plastic ceramic wet mix, to be used in lining the tap-hole 12. The hopper is mounted on and opens into an elongated tubular housing 20. Mounted within housing 20 is a rotatable shaft 22 on which is a screw conveyor 24 for advancing the lining material from the hopper 18 through the housing. A closure or nose piece 26 having an axial recess 28 provided in its rear end 30 closes the front end of the housing and the forward end 32 of the shaft 22 is loosely received in the recess 28 providing a support and bearing for the shaft.
The forward end of the housing 20 has a plurality of openings 34 around its periphery immediately to the rear of the closure 26. There is eccentrically mounted on the shaft 22 between the forward end of the screw conveyor and the nose piece 26 and generally in the transverse plane of the opening 34 a discharge member 36 of generally circular section for forcing lining material radially through the openings 34. The screw conveyor 24 has a single helical flight 37 of uniform pitch for a substantial portion of its length and of a progressively lesser pitch towards its discharge end to increase the pressure on the lining material at the discharge end of the conveyor and assure that it will be extruded through the openings 34 under pressure.
An integral motor and gear case is shown generally at 38 at the rear of the tubular housing 20, and mounted within this case is a motor that is operatively connected to the shaft 22 through reduction gearing supported in the forward end of the casing 38. Mounted on the rear end of the motor shaft 40 is an eccentric weight 42.
When power is supplied to the motor, the shaft 24 will be rotated and since the screw conveyor extends under the hopper l8, lining material will be advanced from the hopper 18 toward the discharge element 36 and be extruded or discharged through the openings 34. While the lining material is extruded through the openings, the rotating eccentric discharge member 36 will force the material through all of the openings and prevent it from all channelling into a path of least resistance. Moreover, as the high part of this discharge member 36 moves past the lining material already in and outside each opening, it creates a pulsing or tamping action to assure a bond between the new lining and the existing masonry. The eccentric weight 42 on the motor, shaft rotating of course at a higher speed than the conveyor, generates a vibration that is transmitted to the lining material around the tube to fluidize it and prevent voids.
Referring now more particularly to FIGS. 3 and 4, the discharge member 36 comprises an elongated body member 43 having first and second sections 44 and 46, respectively. The first section 44 comprises a substantially cylindrical portion 48 with forward and rear ends 50 and 52, respectively. The second section comprises a frustoconical portion 54 which is coaxial with the cylindrical portion 48 and the large diameter end of the frustoconical portion is integrallyformed on the rear end 52 of the cylindrical portion 48. The body member 43 has a bore 56 extending through both portions 48, 54, with the axis of the bore 56 being parallel and spaced from the axis of the member 43. The shaft 24 passes through the bore and is keyed to the body member 43 by a pair of keys 58 and 60.
The operation of the lining apparatus I6 is as follows:
Having first reamed out any obstruction from the tap-hole and blown out any loose material in the hole with a compressed air lance, the lining apparatus- 16 is inserted into the tap-hole until the nose piece rests against the bed or hearth of the furnace thereby placing the peripheral openings of the housing opposite the inner wall of the tap-hole of the furnace. Lining material is then fed forwardly through the housing and if the furnace is still hot, the lining material will have a cooling effect on the various forward parts of the apparatus. The material fed is initially compacted only to the extent necessary to be discharged or extruded through the peripheral openings until the void surrounding the housing is filled. The vibratory action of the housing, generally in a circular motion, further compacts the material against the inner wall of the tap-hole due to the outer wall of the housing acting as a rotary trowel. Progressively, withdrawing the housing, approximately 2 or 3 inches at a time, permits additional material to be extruded into the void and be compacted against the inner wall of the tap-hole. The withdrawal of the housing and compacting of lining material against the inner wall of the hole is continued until the tap-hole is completely lined. The degree of filling of the void can be determined by observing the load or current drawn by the gear motor and the degree of compaction of the lining material can be sensed by the variation in the vibrating action of the housing. By controlling or programming the feed of lining material, periods of dwell can be achieved to impart addition compaction in areas of larger void volume between the housing and inner wall of the tap-hole.
Throughout this specification and accompanying claims, the term lining material is to be construed broadly and is meant to cover a refractory material or any plastic material suitable for lining furnace tap-holes or other similar structures.
While I have particularly shown and described a particular embodiment of the invention it is to be understood that the invention is not limited thereto but that modifications may be made within the scope of the invention and such variations as are covered by the scope of the appended claims.
1. Apparatus for applying a lining of material to the interior of an object comprising:
a. an elongated tubular housing having a closed forward end, a rearward end and at least one opening adjacent its forward end for the discharge of a lining material therethrough, said housing having an outer shape generally conforming to but smaller than the interior of the object to be lined by an amount generally equal to the thickness of the lining to be formed;
b. rotatable feed means mounted within the housing for advancing a lining material therethrough;
c. discharge means within the housing for discharging lining material through the opening; and
d. means for simultaneously driving the feed means and imparting a vibrating action to the tubular housing.
2. Apparatus as defined in claim 1 wherein the feed means comprises a shaft mounted within the housing having a screw conveyor mounted thereon and the dischargermeans comprises an elongated body member eccentrically mounted on the shaft forwardly of the discharge end of the screw conveyor.
3. Apparatus as defined in claim 2 wherein the screw conveyor has a single helical flight of unifonn pitch for a substantial portion of the length of the conveyor and of a progressively lesser pitch towards the discharge end of the conveyor.
4. Apparatus as defined in claim 2 wherein the elongated body member has first and second sections, the first section comprising a substantially cylindrical portion having forward and rear ends and the second section comprising a frustoconical portion integrally formed on the rear end of the cylindrical portion with the frustoconical portion being coaxial with the cylindrical portion and with the large diameter end of the frustoconical portion being adjacent the rear end of the cylindrical portion.
5. Apparatus for relining furnace tap-holes comprising: a. an elongated tubular housing having a closed forward end, a rearward end and at least one opening in its periphery adjacent the forward end thereof for the discharge of a lining material therethrough, said housing having an outer shaped generally conforming to but smaller than the tap-hole to be lined by an amount generally equal to the thickness of the lining to be formed;
b. a supply hopper communicating with the housing for introducing lining material into the housing;
c. a rotatable shaft mounted within the housing and having a screw conveyor mounted thereon for advancing the lining material from the hopper through the housing;
d. a discharge means mounted on the shaft forwardly of the discharge end of the screw conveyor and generally in the transverse plane of the opening of the housing for forcing material radially through the opening; and
e. drive means operatively connected to the shaft for rotating the shaft.
6. Apparatus for relining furnace tap-holes as defined in claim 5 wherein the drive means rotates the shaft and simultaneously imparts a vibratory motion to the housing.
7. Apparatus for relining furnace tap-holes as defined in claim 5 wherein the screw conveyor has a uniform pitch for a substantial portion of its length and a progressively lesser pitch toward its discharge end.
8. Apparatus for relining furnace tap-holes comprising:
a. a supply hopper for a lining material used in lining tapholes;
b. an elongated tubular housing below and communicating with the hopper, said housing having an outer shape generally conforming to but smaller than the tap-hole to be lined by an amount generally equal to the thickness of the lining to be formed;
c. closure means for closing the front end of the housing the housing having at least one opening in its periphery rearwardly of the closure means for the discharge of a lining material therethrough;
d. a rotatable shaft having a screw conveyor mounted thereon supported at its forward end by the closure means, the screw conveyor extending under the hopper;
e. discharge means mounted on the shaft between the forward end of the screw conveyor and the closure and confronting the opening of the housing for forcing lining material radially through the opening; and
f. drive means operatively connected to the shaft for rotating the shaft to advance lining material from the hopper towards the discharge means.
9. Apparatus for relining furnace tap-holes as defined in claim 8 wherein the drive means rotates the shaft and simultaneously imparts a vibrating action to the tubular housing.
10. Apparatus for relining furnace tap-holes as defined in claim 8 wherein the discharge means comprising a body member having a substantially cylindrical portion with forward and rear ends and a frustoconical portion coaxial with the cylindrical portion and with the large diameter end of the frustoconical portion being integrally formed on the rear end of the cylindrical portion, the body member having a bore extending through both portions with the axis of the bore being parallel and spaced from the axis of the body member, the shaft passing through the bore such that the body member is eccentrically mounted thereon forwardly of the discharge end of the conveyor and rearwardly of the closure means.