US 3854635 A
In an arrangement for discharging bulk material from the lower end of a vertically oriented shaft furnace, at least three sliding cars are provided below the lower end of the shaft. The surface of the cars under the shaft has a sector-like configuration. Each sliding car can be moved along a path of travel, inwardly and outwardly relative to the center of the shaft, separate from the path of travel of the other cars. Further, opposite cars can be arranged to be driven simultaneously inwardly and outwardly by a common drive.
Description (OCR text may contain errors)
United States Patent [1 1 Tschinkel Dec. 17, 1974 SLIDING CAR ARRANGEMENT FOR A SHAFT FURNACE Friedrich Tschinkel, Thalwil, 3 Switzerland Maerz Ofenbau AG, Zurich,
Switzerland Filed: Dec. 14, 1973 Appl. No.: 424,706
References Cited UNITED STATES PATENTS 4/1939 Venable 222/199 3,568,894 3/l97l Allen 222/l99 X Primary Examiner-Robert B. Reeves Assistant ExaminerLarry H. Martin Attorney, Agent, or Firm-Toren, McGeady and Stanger In an arrangement for discharging bulk material from the lower end of a vertically oriented shaft furnace, at least three sliding cars are provided below the lower end of the shaft. The surface of the cars under the shaft has a sector-like configuration. Each sliding car ABSTRACT can be moved along a path of travel, inwardly and outwardly relative to the center of the shaft, separate from the path of travel of the other cars. Further, opposite cars can be arranged to be driven simultaneously inwardly and outwardly by a common drive.
6 Claims, 6 Drawing Figures SLIDING CAR ARRANGEMENT FOR A SHAFT FURNACE SUMMARY OF THE INVENTION arrangement of at least three sliding cars for discharging the material substantially over the entire circumferential periphery of the lower end of the shaft.
The characteristic feature of shaft furnaces is the movement of the material from the top to the bottom. If the shaft furnace is used for smelting, the material flows off from the bottom of the furnace. However, if the material being treated in the furnace is solid rather than liquid when it reaches the lower end of the furnace, a suitable device for discharging the material must be used, for example, in shaft lime kilns. There have been a number of different discharging devices used for such furnaces.
In a known embodiment of a shaft furnace, whose shaft has a rectangularcrosssection, a socalled sliding table is used as the discharging device. At a certain distance below the lower end of the shaft, a plate is arranged, mounted on rollers or wheels, and is pushed or moved back and forth for discharging the material from the shaft. With each movement of the sliding table, the material is discharged from one of the two opposite sides of the table, and the column of material in the shaft sinks slowly toward the lower end. In a prismatic shaft, the material descends practically vertically to a plane just-above the sliding table and then it changes its direction of movement toward the discharge outlet immediately above the sliding table. Because of this pattern of movement of the material downwardly through the shaft and out of its lower end, the grains or particles of the materialpassing downwardly through the center of the shaft cover a substantially longerhorizontal path than do the particles located adjacent the shaft walls.
As a result, there is an accumulation of the particles in the center of the shaft and a dislocation of the original horizontal layers of the material.
Frequently, the lower portion of a shaft furnace is used for an after-treatment of the material, for example, the burnt lime in a lime kiln is cooled in the lower zone of the shaft by air passing in counterflow. When the material descends in an irregular manner through the cooling zones, the cooling conditions vary over the horizontal cross section of the shaft or kiln.
Therefore, it is the primary object of the present invention to provide a discharge arrangement for shaft furnace used for the treatment of bulk materials so that the disadvantages experienced where known sliding tables or cars were used for discharging the material on opposite sides of the shaft, is avoided to a great extent.
In accordance with the present invention, the discharge takes place over the entire circumferential periphery of the shaft rather than on just two opposite sides. To afford such discharge, at least three sliding cars are provided below the shaft and the surfaces of the cars extend over the entire cross sectional area of the lower end of the shaft. With this arrangement the material is discharged uniformly about the entire shaft circumference without any appreciable accumulation, such as was experienced in the past.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic side view of a known discharge arrangement for a shaft furnace;
FIG. 2 is a plan view of the arrangement shown in FIG. 1;
FIG. 3 is a schematic plan view of a discharge arrangement for a shaft furnace embodying the present invention;
FIG. 4 is a view, similar to FIG. 3, of a portion of the structure of the discharge arrangement shown in FIG.
FIG. 5 is a schematic representation, similar to FIG. 4, illustrating a portion of the discharge arrangement where the shaft furnace is circular in cross section; and
FIG. 6 is a schematic representation of the difference in which the flow of material from the shaft fumace is influenced by the prior art arrangement of FIG. 1 and by the discharge arrangement embodying the present invention.
DETAILED DESCRIPTION OF THE INVENTION rection of the arrows below the lower end of the shaft and, as indicated by the. flow of material from the shaft,
.as the sliding car is moved in the direction of the arrows, the material flows-from the opposite sides of the shaft outwardly over the opposite ends of the sliding car.
In FIG. 1, the downward path of the material through the shaft furnace l is indicated by crosses for the grains or particles 4 of the material passing downwardly along the walls of the shaft and by rings for the particles 5 of the material descending centrally through the shaft. As illustrated in FIG. 1, the particles 5 cover a substantially longer path in reaching the outlet than the particles 4 with the result that there is a difference in the downward movement of the particles across the cross section of the shaft which has an unfavorable effect on any after-treatment of the material at the outlet from the shaft.
In the discharge arrangement of the present invention shown in FIGS. 3 and 4, instead of being discharged from only twosides of the-shaft, the material is discharged in a uniform manner about the entire circumferential peripheryof the lower end-of the shaft furnace. To provide this discharge arrangement, four sliding cars 6, 7, 8 and 9 are arranged under the shaft I furnace 10 and each of the cars can be moved relative the sectors conforming to the circular shape of the shaft. Basically, the sliding cars in FIG. 3 and FIG. 5, for their surfaces located under the shaft furnace when they are in a fully inward position, have a sector-like configuration with two rectilinear sides diverging outwardly towards the circumference of the furnace and terminating in a rectilinear side in FIG. 3 and in a curvilinear side in FIG. 5.
As indicated in FIGS. 4 and 5, there are gaps l8 and 19 located between the juxtaposed inner edges of the sliding cars which are covered by roof-shaped or saddled-shaped members 20, note FIG. 3, to prevent the material from falling downwardly through the gaps as the sliding cars are moved outwardly from the center of the shaft. The members 20 are dimensioned to afford an adequate cover over the gap during the inward and outward movement of the sliding cars. Where the shaft furnace has a rectangular cross section, it is advisable to limit the rectilinear sides of the sliding cars by the diagonals of the shaft cross section. However, the number of the sliding cars can be varied, particularly if the furnace shaft has a circular cross section and the number can be adapted to different requirements.
It is an important characteristic of the present invention that the material flowing downwardly through the shaft furnace is discharged over the entire circumferential periphery of the lower end of the shaft, as distinguished from the previously known design shown in FIGS. 1 and 2, so that the portion of the material hindered by its location at the center of the shaft in flowing toward the outlet, is substantially reduced. It is assumed that, with the known design of a sliding car as shown in FIG; 2, a quarter of the material in the center of the shaft is obstructed as its flows downwardly toward the discharge outlet and such obstruction is illustrated in the lefthand side of FIG. 6. However, by using the arrangements of the sliding cars shown in FIG. 3, it is possible to cut down on the obstruction to the downward movement of the material so that only about 1/16 of the material is affected, as represented in the righthand side of FIG. 6.
It is preferable if two oppositely disposed sliding cars are'provided with a common drive, for example, a thrust pistons drive, with the two cars moving back and forth', like the sliding table in the known design, along a rectilinear path.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention maybe embodied otherwise without departing from such principles.
l. A discharge arrangement for a vertically extending shaft furnace having a discharge outlet at its lower end and used for the treatment of bulk material comprising at least three sliding cars located below the lower end ,of the shaft and movable in a horizontal plane outwardly and inwardly relative to the central axis of the shaft, the discharge outlet from the shaft extending for the entire circumferential periphery of the lower end of the shaft, wherein the improvement comprises that the surfaces of said sliding cars supporting the material within the shaft furnace combine to extend under the full horizontal cross sectional area of the lower end of the shaft for supporting its contents and each said sliding car is movable outwardly from the center of the shaft along a rectilinear path different from the path of the other said sliding cars. I
2. A discharge arrangement, as set forth in claim 1, wherein the width of each sliding car decreases inwardly from the circumferential periphery of said shaft to its central axis.
3. A discharge arrangement, as set forth in claim 1,
wherein at least two of said sliding cars are arranged as a unit to be driven by a common drive.
4. A discharge arrangement, as set forth in claim 1, wherein said sliding cars can be moved simultaneously outwardly and simultaneously inwardly.
5. A discharge arrangement, as setforth in claim 1, wherein stationary cover members are located within the lower end of the shaft over the juxtaposed edges of said sliding cars and said cover members extend over the adjacent surfaces of said sliding cars so that, as said sliding cars are moved outwardly, said cover members prevent the material within the shaft from dropping between the juxtaposed edges of the cars.
6. A- discharge arrangement, as set forth in claim 2, wherein the surface of said sliding cars under the lower end of said shaft each have a sector-like configuration and, when said sliding cars are in a fully inwardly displaced position, each car hastwo rectilinear sides diverging from a common point located centrally within the shaft furnaces outwardly to the circumferential periphery of the shaft.