Furnace Charging Apparatus

Abstract

A furnace charging apparatus which includes an adjustable chute for distributing the load of charging materials evenly within the furnace. The load of charging materials passes through a plurality of translatable sluices connected above the furnace inlet. The charging load falls through the sluices to a chute which is rotatable and angularly adjustable to distribute the load evenly through the furnace.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a charging device for a furnace and, more specifically, the invention relates to charging equipment for blast furnaces.

2. Description of the Prior Art

The construction of modern high production blast furnaces imposes new and more stringent demands on the charging apparatus due to the increased internal pressures and the increased surface dimensions over which the charge must be evenly distributed within the furnace.

Prior art charging devices such as those employing charging bells and compensating chambers exhibit a number of serious disadvantages where the size of a furnace exceeds given dimensions.

The lower bell of many charging arrangements would be required to have dimensions reaching or exceeding the limit of feasible fabrication techniques. The handling of prefabricated charging bells of suitable size introduces still further problems in regard to both operation and maintenance of the bells.

Optimum uniform distribution of a furnace charge over the entire charging area of the furnace is not possible where the hollow cone in the upper portions of the furnace is directly below the bell of the charging device to unavoidably form the characteristic M-configuration of the cone and bell. This disadvantage can be only partially mitigated in charging bells of large size by means of retractable or angularly adjustable baffle plates.

Although efforts in the past have been made to satisfy the above requirements in larger furnaces, the solutions devised heretofore have only partially eliminated difficulties. Thus, for instance, a charging device exists in which the furnace charge is distributed by means of a charging and distributing snout which rotates about the axis of the furnace. Apart from the nearly insurmountable difficulties to be expected in the construction of suitable bearings and stuffing boxes in furnaces having large throat areas, operational difficulties, particularly related to high temperatures of the furnace, can arise when such an arrangement is used.

SUMMARY OF THE INVENTION

According to the present invention, a charging device for a furnace such as a blast furnace is composed of a spreader element centrally arranged in an inlet within the head of the furnace. The spreader element is mounted for both rotation about the axis of the furnace and angular adjustment with respect to the axis. Feed mechanisms including charging sluices are disposed above the furnace and the spreader element to supply the charging load. A drive mechanism is connected to the spreader element to provide the rotary and angular displacements during the charging operation. Controlled movement of the spreader element provides a more uniform distribution of the charge within the furnace.

It is accordingly an object of the invention to avoid a number of the disadvantages of the prior art apparatus and to provide a charging arrangement which can insure optimum distribution of the charging load over the entire throat area of a large furnace. In addition, the charging process is accomplished simply and accurately in either a continuous or discontinuous fashion.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel charging apparatus together with its numerous objects and advantages will be described in conjunction with the following drawings wherein the same elements bear the same reference numerals throughout the several figures.

FIG. 1 is a partially sectioned view of the novel charging device according to the present invention.

FIG. 2 is a partially sectioned view of the driving system for the charge distributing spreader.

FIG. 2a is a partial view of the charge distributing spreader at a selected angular position.

FIG. 3 is a cross-sectional view of the transmission for the driving system shown in FIG. 2.

FIG. 4 is a partially sectioned view of a second embodiment of the novel charging arrangement according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the upper portion or head of a modern, high-production furnace, generally designated 1, having a throat of large diameter. The particular furnace shown is a blast furnace alternately charged through two or more charging sluices 2, 2' and a distributing device to be described in greater detail below. The blast furnace charging load is alternately fed to the charging sluices 2, 2' by a suitable conveyor such as conveyor belt 5 and a reversible spreader element 6. The charging load passes from the conveyor belt 5 through two or more tubs or skips 4, 4' and charging hoppers 3, 3' to the sluices 2, 2'.

Each of the charging sluices 2, 2' is equipped at its inlet and exit with suitable doors 7 and 10 respectively. The doors are open and closed at given times during the charging cycle to allow material to pass into and from the sluices. For pressure equalization, the charging sluices 2, 2' are equipped in a conventional manner with intake and outlet valves 8, 8'.

To simplify and facilitate removal and installation of the charging sluices, quick release flange joints are provided at both the inlets and exits of the sluices. Additionally, the sluices are mounted on rollers which ride on rails 9 and 9', respectively. The simple construction of the charging sluices with the disengageable connections allows a quick changing of the spreader arrangement disclosed below. The rapid displacement of the charging device is one of the important advantages of the present invention. As a result, the blast furnace need only be stopped for a time which is relatively short compared to shutdown times with charging systems of the prior art.

The release of the furnace charging load from each of the charging sluices 2, 2' is accomplished through the exit door 10 which when opened is completely removed from the path of the charging materials. An adjustable throttle element 11 controls the feed rate of the charging load into the furnace. The throttling of the charging load is only possible, however, for charges of uniform grain size. Where the grain size is irregular, it may be more advantageous to provide other feed control means in place of the throttling element, for example discharge spouts or launders.

The charging loads issuing from the charging sluices 2, 2', respectively, are directed into a stock hopper 12 and pass from the hopper through a fixed, vertical spout 13 to an adjustable spreader or chute 15 fitted within the furnace head. In this regard, it should be noted that the ratio of the inside dimensions of the feed spout 13, that is the length to diameter ratio, should be so selected that the load strikes the adjustable spreader chute 15 from an approximately vertical direction.

The adjustable chute 15 is fitted within the furnace head in such a manner that it can rotate about the vertical axis of the blast furnace and be adjusted angularly with respect to the axis at the same time. Thus, as indicated in FIG. 1, the chute 15 can be angularly adjusted between positions 18, 18', 18" and 19 to distribute the stream of charging material throughout the plane of the furnace at the stocking level, such as shown for example at 20. It is thus possible to reach any portion of the stocking level plane by suitable rotation and angular adjustment of the spreader chute 15. As a practical example, the charging load can be distributed in concentric rings or in spirals produced by continuous adjustment of the angular setting as the spreader chute 15 is rotated. Particular points to be fed in the stocking level plane can also be selected.

In order to compensate for irregularities in the distribution of the charging load due to fluctuations in the incoming stream of materials, it may be advantageous to control the opening of the charging sluices 2, 2' in accordance with a predetermined program. In particular, the size of the discharge opening in a sluice may be regulated in accordance with the particular angular position of the spreader within the furnace.

The heighth of the stocking level within the furnace can be measured in a conventional fashion by feeler gauges 17, 17' between each of two charging operations. Owing to the absence of the lower bell and associated hopper of the prior art charging devices, the feeler gauges can be distributed circumferentially around the blast furnace at a number of azimuthal positions with respect to the vertical axis of the furnace. Similarly, automatic load controlling devices can be disposed at different levels in the furnace throat for monitoring the charging process.

In order to take fullest advantage of the distributing system according to the present invention, it is desirable to employ one or more radiation profilometers arranged in different planes perpendicular to the vertical axis of the blast furnace. With such profilometers, a continuous record of the profile of the stocking level is obtained during the charging periods and the distribution of the loading charge can be controlled accordingly. It is, of course, equally possible and in many cases advantageous to employ a combination of both automatic load control devices and radiation profilometers for monitoring and controlling the charging process.

As seen from FIG. 1, the spreader chute 15 in accordance with the present invention is attached to the blast furnace head 1 by means of a flange joint 23 for simple and rapid detachment. With this flange joint, the whole spreader can be detached and removed by means of a suitable suspension gear 21 and a crane installation.

The elimination of the lower bell and hopper of the prior art charging devices allows the gas discharge flues 16 to be disposed in the furnace top or head 1 in an optimum position with regard to gas flow from within the furnace. Moreover, the assembly described above results in a considerable reduction in the overall height or drop height of the entire charging arrangement.

FIG. 2 shows the inlet spout 13 and a novel driving arrangement for the spreader chute 15. As seen here, in order to eliminate the already well known difficulties caused in the design of large diameter stuffing boxes by high charging pressures encountered within the furnace throat, the driving furnace means according to the present invention is so arranged that only rotating shafts of small diameter are required to be sealed at the interface of the spout 13 with the external atmosphere. The actual drive system incorporates a rotating cylinder or bush 25 having rotating ring 26 at its lower end from which the spreader chute 15 (shown in two orthogonal positions) is pivotally suspended on two brackets 27 by suitable connecting pins 28.

The rotating bush 25 is connected by means of a ball bearing 29 with the fixed inlet spout 13. Bearing 29 allows spreader chute 15 to be rotated by drive means such as described hereinafter. In order to adjust the spreader chute 15 angularly with respect to the vertical axis of the sleeve 13 and furnace, an actuating rod 30 is connected to the chute 15 and moves together with its actuating sleeve 31 in the vertical direction. The actuating rod 30 and sleeve 31 are linked by a cam-following roller 34 to a second rotating sleeve 32 concentrically mounted with respect to the rotating bush 25. The sleeve 32 is also linked with the rotating bush 25 by means of a ball bearing 35. The rotating sleeve 32 has a sinusoidal camming slot 33 in which the roller 35 is engaged. As will be explained in greater detail below, rotation of the sleeve 32 with respect to the follower 34 produces a vertical displacement of connecting rod 30 and an angular displacement of the spreader chute 15. The sleeves or bushes 25 and 32 are rotated by gears 38 and 39 respectively. The gears 38 and 39 are suitably actuated by an externally located driving mechanism. The movements of the various driving elements for spreader chute 15 are all accommodated within the fixed housing 36. The housing 36 is attached in a gas-tight manner to the inlet of blast furnace head 1 (FIG. 1) and to the intake spout 13 by means of detachable connections. As previously described, only the drive shaft for gears 38 and 39 pass through the housing 36 and, therefore, the sealing problems are advantageously reduced to a minimum compared with the charging arrangements of the prior art.

To avoid accumulation of furnace dust and to cool the system, an inert gas such as nitrogen may be introduced through the pipe 37 into the housing 36. Such gas helps to scavenge the spaces between different moving parts. Similarly, a lubricating fluid may be sprayed on the moving parts in conjunction with the cooling gas to provide continuous lubrication of the moving parts.

Although not shown in FIG. 2, it is also feasible to provide suitable means for cooling the spreader chute 15. Cooling chute 15 considerably increases the working lifetime of the chute.

As seen from FIGS. 2 and 2a, the adjustable chute 15 can be tilted in a vertical plane on the pivot pins 28 by actuating rod 30. Pivoting the chute 15 in this manner adjusts the angular position of the chute with respect to the axis of the blast furnace. The angular adjustment in conjunction with the rotational adjustment of the chute 15 permits each point in the stocking level plane to be reached with the stream of materials discharging along the chute from the sluices 2 and 2' (FIG. 1). The lowering or raising of the actuating rod 30 is accomplished by relative movement of the rotating sleeves or bushes 25 and 32. The relative motion is obtained by rotating the two bushes 25 and 32 at slightly different speed in a manner to be described hereinafter in conjunction with FIG. 3. The relative motion between the bushes 25 and 32 causes the cam following roller 34 to move along the sinusoidal cam slot 33 whereby sleeve 31 and connecting rod 30 are caused to move vertically.

FIG. 3 shows the transmission of the driving or actuating means for the spreader chute 15. The main driving motor 41 operates through a clutch 43; braking device 44; transmission gearing 45, 46; drive shaft 47 and a ring gear 48 to drive the internally located rotating sleeve 25. Motor 41 similarly drives a planetary transmission 49 comprising ring gear 50 and two planet gears 51, 52. The planet gears 51, 52 are in turn coupled through gear train 53 to drive shaft 54 and its associated ring gear 55. Ring gear 55 is connected to and drives the external rotating sleeve 32. When the transmission ratios of the various gear trains have been correctly selected, both rotating sleeves 25 and 32 are driven at the same speed and in the same direction. With such speeds, the angle of inclination of the spreader chute 15 does not vary. The speed of rotation and angle of rotation are monitored for control at an indicating device 56 connected to the gearing 46.

The rotational speed of the planet gears 51, 52 in the planetary transmission 49 can be varied by means of an auxiliary drive motor 42. Motor 42 is connected by means of clutch 57 and gear train 58, 59 to the central sun gear of the planetary transmission 49. Since the planetary transmission 49 serves as a differential drive, the operation of motor 42 changes the rotational speed of gear train 53 and ring gear 55 so that the speeds of sleeves 25 and 32 are no longer synchronized. The variation in speed depends on the speed of motor 42. As previously described with reference to FIG. 2, the angular setting of the spreader chute 15 with respect to the vertical axis of the blast furnace is varied when synchronism between the rotations of sleeve 25 and 32 is lost. After the auxiliary motor 42 stops, the spreader chute 15 continues to rotate with motor 41 but at a new angular setting. Similarly, after the main driving motor has been stopped, the non-rotating spreader chute 15 can be set at different angular positions by means of the auxiliary drive motor 42. An angular setting indicator 60 allows the angle of the spreader chute to be directly monitored and controlled. Limit stops may be fitted in the indicator 60 to prevent the spreader chute 15 from being moved outside preset extreme angular positions.

As seen in FIG. 3, the novel driving arrangement allows the housing 36 which is exposed to the full pressure of the furnace throat to be very simply and effectively sealed since there are only two small diameter drive shafts 47 and 54 which must be sealed at the walls of housing 36.

Of course, other driving means and arrangements for altering the angular setting of the spreader chute may be employed. Thus, it would be possible to provide hydraulic control means connected to the chute to adjust the angular position. It is preferable, however, to ensure that the angular setting of the chute be continuously variable while the spreader chute is rotated.

An alternate embodiment of the charging arrangement according to the present invention is shown in FIG. 4. In the alternate embodiment, a double spreader chute 61 is used to distribute the charging load in a manner similar to that disclosed in the embodiment of FIG. 1. The charging load is alternately fed to the chute 51 through sluices 62, 62' the stock hopper 63 and the feeder 64.

The double spreader chute 61 is rotated by means of a hollow shaft 66 passing through a centrally located cylindrical bush 65. The chute 61 and the shaft 66 are rotated by an external means not shown in the figure.

Continuous variation of the angular setting of the double spreader chute 61 is effected by means of a connecting rod 67 centrally located in the hollow shaft 66. The rod 67 is adjusted vertically within the shaft 66 by a hydraulic actuating means 68 at the upper end of shaft 66.

While the novel charging apparatus has been described in several preferred embodiments, it will be apparent to those skilled in the art that various modifications and substitutions can be made to the apparatus without departing from the spirit of the invention. Accordingly, the charging apparatus has been described in the foregoing specification by way of illustration rather than limitation.

Claims

What is claimed is:

1. Apparatus for charging a furnace having a charging inlet in the upper portion of the furnace comprising:

spreading means mounted within the furnace adjacent the charging inlet for distributing material entering the furnace through the inlet to various positions within the furnace, said spreading means being rotatable about an axis and independently angularly adjustable with respect to said axis;

drive means positioned externally of the furnace for controlling the rotational motion and angular orientation of said spreading means with respect to said axis;

first driving means for rotating said spreading means about said axis, said first driving means being positioned interiorly of a wall of said furnace;

second driving means for angularly adjusting said spreading means independent of the rotation thereof, said second driving means being positioned interiorly of a wall of said furnace;

actuating means extending from said drive means through the wall of the furnace for coupling said drive means to said first and second driving means;

means positioned externally of the furnace for storing material to be delivered to the interior of the furnace, said storing means including at least two containers, each of said containers having inlet and exit openings;

means for selectively sealing and opening said storing means container inlet and exit openings, said selectively sealing and opening means preventing escape of gas from the furnace when in the sealed position;

spout means penetrating the wall of the furnace, said spout means providing communication between said storing means container exit openings and said spreading means whereby material to be delivered to the furnace will be directed by said spout means from either of said storing means containers to said spreading means by said spout means when the means for selectively sealing and opening the exit openings of the containers are in the open position.

2. The charging apparatus of claim 1 wherein:

the storing means containers are detachably coupled to said spout means; and

a translatable support is provided, the storing means being mounted from the translatable support whereby the storing means can be detached from the furnace and translated on the support away from the furnace inlet.

3. The charging apparatus of claim 1 wherein:

the spreading means comprises a chute which is sized to fit through the inlet of the furnace for removal from the furnace.

4. The charging apparatus of claim 1 wherein:

said first driving means includes a rotatable mounting bracket rotatably connected to the furnace at the inlet; and

the spreading means is pivotally supported from the mounting bracket means whereby the spreading means can be rotated and angularly adjusted with respect to the inlet.

5. The charging apparatus of claim 1 wherein:

said first driving means includes a first rotatable sleeve mounted in the inlet and connected to said spreading means; and

said second driving means includes a second rotatable sleeve mounted in the inlet coaxially with the first rotatable sleeve, said second sleeve having a camming slot circumscribed in the sleeve, and a cam following rod engaging the camming slot at one end and being pivotally connected to the spreading means at the other end.

6. The charging apparatus of claim 5 wherein;

the drive means includes motor means connected with the coaxial sleeves for synchronously and differentially rotating the sleeves.

7. The charging apparatus of claim 5 wherein:

the drive means includes two motors and a planetary transmission, the transmission having inputs connected to each of the motors and an output connected to one of the coaxial sleeves.

8. The charging apparatus of claim 7 further comprising:

means for shielding and cooling said first and second driving means whereby said first and second driving means will not be adversely affected by thermal radiation from the furnace.

9. The charging apparatus of claim 1 wherein:

the spreading means includes two adjustable chutes.

10. The charging apparatus of claim 9 wherein:

a hollow shaft is mounted adjacent the inlet with one end of the shaft centrally positioned with respect to the inlet in the furnace; and

the two adjustable chutes are pivotally mounted to the one end of the hollow shaft.

11. The charging apparatus of claim 10 wherein:

the hollow shaft extends through the inlet to the exterior of the furnace and is rotatably mounted to the furnace, the shaft being connected to the drive means for rotation about the shaft axis; and

hydraulic actuating means mounted externally of the furnace connect through the hollow shaft to the two chutes for adjusting the chutes pivotally on the end of the rotatable shaft.

12. The charging apparatus of claim 1 further comprising:

load monitoring means for monitoring level of the material within the furnace.

13. The charging apparatus of claim 1 further comprising:

means for controlling the rate at which material is delivered to the furnace from the storing means containers, said rate controlling means including throttle valve means associated with each of said container exit openings.

14. The charging apparatus of claim 1 wherein said actuating means comprises:

reciprocating means penetrating the furnace wall and connecting said drive means to said spreading means;

rotating means penetrating the furnace wall and coupling said drive means to said spreading means.

15. The charging apparatus of claim 14 further comprising:

means for shielding and cooling said first and second driving means whereby said first and second driving means will not be adversely affected by thermal radiation from the furnace.

16. The charging apparatus of claim 1 further comprising:

means for shielding and cooling said first and second driving means whereby said first and second driving means will not be adversely affected by thermal radiation from the furnace.

17. Apparatus for charging a blast furnace which operates at high pressure and high temperature, the charging apparatus including:

a housing at the upper portion of said furnace, the interior of said housing being exposed to pressure in said blast furnace, said housing having an inlet spout communicating with the interior of said furnace to charge said furnace;

spreading means located in the upper portion of said furnace and positioned to receive charging material from said inlet spout, said spreading means being rotatable about an axis and independently angularly adjustable with respect to said axis;

first driving means in said housing for rotating said spreading means about said axis;

second driving means in said housing for angularly adjusting said spreading means independent of the rotation thereof;

drive means positioned externally of said furnace for controlling the rotation and angular adjusting of said spreading means;

actuating means extending from said drive means through sealed passages in said housing to said first and second drive means;

means for introducing a fluid into said housing to clean and cool said first and second driving means;

storing means positioned externally of the furnace for storing material to be delivered to the interior of the furnace; and

means for delivering said material from said storing means to said spout means.

18. Charging apparatus as in claim 17 wherein said storing means includes:

at least two containers, each container having inlet and outlet openings; and

means for selectively sealing and opening said container inlet and exit openings, said selectively sealing and opening means preventing escape of gas from the furnace when in the sealed position.

19. The charging apparatus of claim 17 wherein:

the spreading means comprises a chute which is sized to fit through the inlet of the furnace for removal from the furnace.

20. Charging apparatus as in claim 17 wherein:

said first driving means includes a rotatable mounting bracket means, said spreading means being pivotally supported from said mounting bracket means.

21. The charging apparatus of claim 17 wherein:

said first driving means includes a first rotatable sleeve mounted in the inlet and connected to said spreading means; and

said second driving means includes a second rotatable sleeve mounted in the inlet coaxially with the first rotatable sleeve, said second sleeve having a camming slot circumscribed in the sleeve, and a cam following rod engaging the camming slot at one end and being pivotally connected to the spreading means at the other end.

22. The charging apparatus of claim 17 further comprising:

means for shielding said first and second driving means against thermal radiation from the furnace.