US3633897A

US3633897A - Shaft furnace operating with relatively high gas pressures and method of charging the same

Info

Publication number: US3633897A
Application number: US796997A
Authority: US
Inventors: Rudolf Vogel
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-02-06
Filing date: 1969-02-06
Publication date: 1972-01-11
Anticipated expiration: 1989-01-11
Also published as: SE335745B; GB1263729A; LU57889A1; FR2001330A1; BE728010A

Abstract

A shaft furnace, particularly a blast furnace, includes a furnace head having a gas pipe extending substantially centrally therefrom. A charge distributing means in the furnace head includes a frustoconical bell associated with a reversely directed frustoconical pan normally resting on the bell. The bell is rotatable and vertically displaceable. When the bell is moved downwardly, a lip on the pan engages a fixed support so that the bell separates from the pan for charging of the material into the furnace. Charge storage and conveying means are interchangeably associated with the furnace. The charge material is delivered into the storage means by a simple pouring operation, and is released to fall substantially freely into a self-supporting pile at one end of a conveyor which extends transversely between the storage means and the furnace head, and is pressure sealed. The conveyor preferably slopes slightly from the storage means to the furnace head, and means are provided to seal off the furnace head when the conveyor and the storage means are disconnected from the blast furnace.

Description

z Unite States P tent [72] Inventor Rudolf Vogel Wendemuhlenbergstrasse 20-22, Salzgitter-Bad, Germany [2!] Appl. No. 796,997

[22] Filed Feb. 6, 1969 [45] Patented Jan. 11, 1972 [32] Priorities Feb. 6, 1968 [3 3 Germany June 26, 1968, Germany, No. P 17 58 552.3; June 26, 1968, Germany, No. P 17 58 556.7; Jan. 18, 1969, Germany, No. P 19 02 500.4; Feb. 3, 1969, Germany, No. P 19 05 117.3

[54] SHAFT FURNACE OPERATING WITH RELATIVELY HIGH GAS PRESSURES AND METHOD OF CHARGING THE SAME 17 Claims, 8 Drawing Figs.

[5 6] References Cited UNITED STATES PATENTS 2,733,912 2/1956 Newcomb et al. 266/27 3,137,399 6/1964 Renkes et al. 266/27X 3,198,623 8/1965 Evans et a1 266/27 X Primary Examiner.lames M. Meister Attorney-McGlew and Toren ABSTRACT: A shaft furnace, particularly a blast furnace, includes a furnace head having a gas pipe extending substantially centrally therefrom. A charge distributing means in the furnace head includes a frustoconical bell associated with a reversely directed frustoconical pan normally resting on the bell. The bell is rotatable and vertically displaceable. When the bell is moved downwardly, a lip on the pan engages a fixed support so that the bell separates from the pan for charging of the material into the furnace. Charge storage and conveying means are interchangeably associated with the furnace. The charge material is delivered into the storage means by a simple pouring operation, and is released to fall substantially freely into a self-supporting pile at one end ofa conveyor which extends transversely between the storagemeans and the furnace head, and is pressure sealed. The conveyor preferably slopes slightly from the storage means to the furnace head, and means are provided to seal off the furnace head when the conveyor and the storage means are disconnected from the blast furnace.

PATENIED JAM 1 1972 SHEET 1 BF 7 meme m1 1 19:2 36331897 cum u 0F 7 MIMI-N70? Pudalf 1 0651 Mel/M SHAFT FURNACE OPERATING WITH RELATIVELY HIGH GAS PRESSURES AND METHOD OF CHARGING THE SAME BACKGROUND OF THE INVENTION The uniformity of gas flow through the burden or charge column of a blast furnace is directly proportional to the intensity of the reducing process, that is, to a desired rapid furnace operation. In addition to the distribution of the charge materials, such as ore, sinters, pellets, coke, and additives, the gas pressure prevailing in the furnace controls. the progress of the reaction in the individual charge layers or beds. While the uniform laying on of beds of charged material as free from segregation as possible is intended to effect a gas flow of equal degree at all points of the furnace cross section, more recent findings indicate that the reduction tendency of iron oxides of a higher degree is influenced advantageously if it effected under high pressure. On the assumption of an effective flow of gas through the charge beds, and a uniform sinking of the charge beds, a greater yield of pig iron can be obtained at higher gas pressures.

Considered purely from the mechanical standpoint, a higher gas pressure has a favorable effect on the flow of irregularly composed beds of materials of different granularity.

Increasing the gas pressure involves considerable difficulties. Known furnace top distributing means or distributing gear comprise single or double bell arrangements, with the two bells forming a sluice chamber so that either one or the other clears a path for the charge material. In either case, the charge material slides over the conical sealing surfaces of a bell, and this leads to considerable wear. Additionally, dust erosion continuously increases any leaks. The surface parts swept by the charge material, in particular the surface parts of the charge distributing means, are subjected to heavy wear by abrasion. The closing edges of the charging bells and the surfaces of the hoppers cooperating therewith are particularly exposed to this heavy wear.

On the other hand, in the course of time, an ever increasing deformation of the bells, as well as of the corresponding seats, occurs due to the inevitable thermal stresses which are caused by the high operating temperatures. Due to these operating conditions, the furnace zone cannot be maintained sufficiently tight or leak proof over the long run when bell-type charge distributors are used. Frequently, remachining and buildup welding are resorted to to reduce the leakages to a tolerable level.

For the reasons just mentioned, relatively high pressures cannot be attained using the principle of the double bell-type charge-distributing means, or can be attained only temporarily in an initial state. Due to the inevitable wear by dust erosion, this initial state is changed rapidly depending on the wear resistance of the material used for the charge-distributing means.

The difficulty of charging high-pressure furnaces is not due solely to the problem of providing effective sealing, as the material can be introduced by means of a sluice (gate valve) with more or less large loss of gas. In attempting to avoid the use of the conventional double bell charge-distributing means, considerable problems have been encountered in feeding the material in a suitable manner without the charge material suf fering damage with respect to major abrasion. Large quantities of material in a dust form, due to such major abrasion, adversely effect the working of the furnace. The conditions are different for different charge materials, such as ore in lumps, sinter and pellets, so that there is no generally advantageous feeding method. The cause lies in an unfavorable arrangement of the apparatus so that, in particular, difficulties related to the process form an uncontrollable secondary effect.

The process defects are manifested, for example, in an excessive height of fall-of the charge material, so that an undesirable high abrasion must still be accepted. Considered from the apparatus standpoint, there is an added defect which also, in some sense, is capable of exerting an influence on the process aspect. Due to the arrangement of sealing elements and distributing devices in the region of higher temperature, or particularly in the area of a main exhaust gas stream, there result thermal expansions and thermal stresses which prevent a sufficient sealing effect of the elements and prevent the wear being kept within acceptable limits.

A known attempted solution, with respect to the process aspect, is to let the material fall into a rotatable distributor by means of a known double bell arrangement involving a bell having a small diameter, but with a relatively great height of fall so as to effect, from the rotatable distributor and through baffle aprons, distribution of the charge material in the furnace zone. In this attempted solution, the great height of fall is unfavorable for a low abrasion of the charge material and, in addition, neither are the essential sealing members removed from the zone of the exhaust gas stream nor is the problem of wear due to dust erosion solved.

SUMMARY OF THE INVENTION This invention relates to the charging of shaft furnaces, such as blast furnaces, operating with relatively high gas pressures and, more particularly, to a novel method of charging such shaft furnaces and a novel design of the shaft or blast furnace for practicing the method.

The problem solved by the present invention may be divided into two parts, of which one part is the provision of technical process conditions for a safe introduction of the charge materialand, at the same time, the effecting of the useful distribution of the charge material in the furnace zone. The other part, which is to some extent independent of the first part, is the provision of a more favorable design of the apparatus and, in this part, and in particular, the stress, due to heat and dust as well as the wear occurring due to entrainment of the dust in the flow, must be taken into account. The particular difficulty of the problem solved by the present invention lies in the interrelation of the process and apparatus measures, with respect to the elimination of mutual influences.

The invention is directed to a method for charging shaft furnaces operable at relatively high gas pressures, and in particular pressure-type blast furnaces where the charge material is conveyed from a pressure-sealed storage zone into the furnace zone and is distributed on the charging surface therein. In contradistinction to known procedures, in accordance with the invention, the charging is effected in such a way that the charge material is supplied to the storage zone by a simple pouring procedure. At the filling point of the storage zone, the material descends in a substantially free fall, forming a self-supporting pile. The charge material is introduced into the furnace in a conveying direction extending transversely of the falling direction in the storage zone and through a pressure-sealed channel or passage, to a point in the furnace directly above the charged distributing means in the furnace zone.

The outstanding advantages of this procedure reside in a substantial reduction, of more than 50 percent, of the height of free fall of the material previously used. A further advantage is that the material is supplied to the furnace zone outside the main exhaust gas flow so that, under suitable flow conditions, a continuous direct opening of sealing members is avoided. Thus, the quantity of dust reaching the sealing members can be greatly reduced, so that the wear of the mechanical parts is diminished. Furthermore, the mechanical parts can now be positioned outside the hot zone, so that sealing at much lower temperatures is possible. The path of movement of the charge material is thus characterized by avoidance of frequent falling of the charge material since, as the material is fed into the storage zone and is discharged onto the distributing device, only small heights of fall must be overcome. The fall heights become essentially insignificant in view of the invention procedure.

In accordance with the invention, the blast furnace has, within the furnace head, a distributing device which is suppliable with charge material from one or more storage bunkers located outside the furnace zone. The material in the storage bunkers is directed through a sluice chamber into an hermetically sealed conveyor means leading into the pressure-sealed furnace zone. An advantageous feature is that the furnace head has hardly any movable elements installed therein.

In particular, the conveyor means, either during the operating cycle or for repair purposes, can be disconnected completely from the furnace. In addition, the conveyor means can deliver the material at a relatively small distance above the pile of material already in the furnace, so that the material in the furnace is protected to a large extent. The conveyor means itself is under thermal stress only insofar as it cannot be avoided by virtue of the necessity of operating in the region of the hot exhaust gas stream during the charging periods. By comparison, the distributing device is simpler to construct and therefore more capable of resisting stresses and of a longer life.

In further accordance with the invention, the blast furnace includes a distributing device in the form of a rotatable bell which can be lowered for discharging material onto the material already in the furnace. This bell has a frustoconical surface on which there rests a freely movable pan into which the material is delivered from the conveyor means. As the bell descends, this pan is supported on brackets fixed on the furnace shell and distributed around its circumference. Thus, the entire distributing means can now operate suspended in the furnace zone without being in contact with the large number of movable parts operating under dirty and hot conditions. All parts therefore can expand, warp and undergo wear, under the action of the furnace heat, without there being any effects impairing the functional capacity of the distributing means.

The distributing means provides for a lateral feeding of the charge material from the furnace wall, with the pan rotating continuously or intermittently and with the vertically displaceable bell carrying both the material and the pan. When the material is to be distributed into the furnace zone, the complete bell and pan unit, carrying the charge material, is lowered until the pan is supported, by its peripheral edge, on brackets fixed on the furnace wall. Then the bell is moved further downwardly and, with this lowering of the bell, dropping of the material from the bell surface into the furnace zone is effected, with different diameters of the furnace cross section being loaded with material in dependence upon the lowered position of the bell.

The hermetically sealed conveyor means may comprise a vibratory conveyor trough, which is particularly well suited for the prevailing operating conditions as its drive elements are more easily accessible. Also, with a vibratory conveyor trough, no movable parts need be subjected to the stress of heat and dust although actually at lower temperatures. The parts no longer have to endure the stresses of known arrangements because of the greater distance from the hot exhaust gas stream. Since the vibratory conveyor trough is positioned outside the furnace head, it is easier to cool and therefore can be protected from higher thermal stresses. As an additional protection, the hermetic enclosure of the conveyor means is designed so as to radiate heat therefrom. Alternatively, forced cooling may be provided to protect the conveyor means and the adjacent sluice chamber closures, and this may be done in such a manner that the hermetic enclosure of the conveyor means is surrounded by a flowing coolant.

To provide for rapid exchange or replacement of the conveyor means, or to carry out repairs on the charging system while the furnace is operating, the hermetic enclosure containing the conveyor means can be closed off in a gasproof manner with respect to the furnace zone.

Outflow of top gas during operation of the furnace can be avoided by providing, between the furnace head and the storage bunker having the sluice chamber, a blower connected to the hermetic enclosure so as to maintain a counter pressure with respect to the furnace zone. As long as the pressure in the furnace zone exceeds this counter pressure, there is a moderate outflow of top gas from the then opened sluice chamber but, when equilibrium prevails, this outflow is suppressed. Also, such outflow occurs only during the time required to open and close the sluice or gate valves. Depending upon the equilibrium state, a small quantity of the counter pressure gas can enter the furnace zone and is entrained by the main exhaust gas stream. However, it is possible to avoid an increase in volume of the main exhaust gas stream. Preferably, purified top gas is used as a counter pressure gas so that the energy content of the exhaust top gas does not undergo variation.

In accordance with the invention, the storage bunker, together with the sluice chamber, is formed as one structural unit which can be run into operating position on guide means and which is exchangeable or interchangeable. With the usual sliding closures, it has been found that working with gas masks is extremely difficult for the operating personnel, and should be avoided as much as possible. With the present invention, the escape of top gas can be prevented by closing the furnace bulkhead. The downtime for repair work is extremely short, because an entire structural unit can be held in readiness, and possibly only parts subject to wear need to be replaced. The reduction of the downtime, and the resulting increase in the production of the furnace, justifies keeping in stock a reserve storage bunker with a sluice chamber.

The invention also has as an objective the further reduction of the thermal stress of the various parts. To provide still greater safety of operation or longer life for the hermetically sealed conveyor means, the conveyor means terminates outside the furnace and the charge material is transferred to a gasproof connecting line which opens into the furnace essentially above the charge point of the distributing means. This has the advantage that the longitudinal conveyor means thereby is removed from the direct influence of the furnace atmosphere, so that stresses thereon are less and the conveyor means is more quickly and easily accessible.

The connecting line may be designed as a chute inclined to the furnace axis, and this leads to a simple and aimed feeding of the material into the distributing device, with the wear of the connecting line being maintained low. Alternatively, this short connecting piece may be made of wear-resistant material, and it is advantageous that the end of the longitudinal conveyor nearest the furnace also be made of heat and wear-resistant material as well as being made interchangeable.

in accordance with the invention, the drive for the gas shutoff means and the conveyor drive are controllable jointly and in dependence on the charging cycle. Thereby it is possible, for example, in a program-controlled sealing cycle, to include the gas sealing valve in this cycle in such a manner that this valve is closed whenever feeding of material into the distributing means is not necessary, whereby the outflow of top gas through the casing of the longitudinal conveyor is limited to a minimum.

The advantage of a distributing device of the simplest design, which is independent of the scaling function in pressure-type blast furnaces, manifests itself in the possibility of providing further improvements to satisfy the problems of working of the furnace. For example, such improvements may have the purpose of varying the pile in the furnace. However, the objective to be maintained is to provide a distributing device which is of simple and sturdy construction and which is reliable in operation, as well as such a device which can be arranged in zones of the further furnace head wherein it is removed from the direct action of temperature, top gas and dust.

in accordance with the invention, the distributing device includes a rotatable and axially displaceable distributor pan with which there is associated a closure part having an edge which rests in a sealed relation against the smaller edge of the distributor pan when the distributing device is in filling position, and whose other edge or periphery is engageable with mounting means fixed on the furnace. As contrasted to known arrangements, the rotation and lifting movement is concentrated on a simple part of the distributing device, namely the distributor pan, while the closure element is moved only indirectly through the distributor pan. Thereby, the inner zone of the furnace head can be kept free from passages therethrough for actuating elements in the vicinity of the top gas pipe. The major part of the distributing arrangement can be arranged outside of the furnace, and this favors a more undisturbed discharge of top gas.

The closure part, in accordance with a further feature of the invention, is designed as a truncated hollow cone tapering toward the top gas pipe, and this cone is placed adjacent the smaller diameter edge of the distributor pan with the interposition of a packing ring. This design promotes unhindered outflow of the top gas and contributes to the rigidity of the distributing device as well as to the satisfactory evacuation thereof.

Despite the simple design of the distributing means, the latter can be designed to provide the fundamental conditions with respect to the production of certain pile profiles or, alternatively, with respect to uniform charging over the entire charging cross section. For this purpose, the distributor valve can comprise two or more sections each of which is suspended from a vertically displaceable supporting device, consisting essentially of a solid or hollow drive shaft extending through the furnace head. Thereby, differently arranged and directed outlet apertures are available for the charge material contained in the distributing means in accordance with whether the sections of the closure part are moved into engagement with each other, through their supporting device, or whether the closure part is separated from the distributor pan after the latter has come to rest on its support brackets. Advantageously, the separation zones extend normal to the axis of the drive shafts, so that a pile concentric to the axis of the drive shaft can be attained.

Auxiliary brackets may be provided between the main brackets supporting the distributor pan, and these auxiliary brackets can define a second discharge plane for the distributor pan. The furnace brackets then may be made vertically displaceable or movable out of the path of movement of the distributor pan. In principle, such a measure provides the possibility of effecting charging of very large charging surfaces, such as occur in large volume blast furnaces, so that these furnaces can now be operated by the high-pressure method.

A particularly simple, sturdy and thus stress-resistant arrangement and design, equal to the usual blast furnace operation, of the conveyor comprises making the conveyor a thrust conveyor which is essentially two troughs displaceable relative to each other. The inner trough is driveable and the driving stroke is adjustable as to speed and distance. This results in a favorable interrelation between the process and apparatus aspects, as the drive can be outside the sealed channel and thus easily accessible. A light construction, possessing adequate strength, increases the specific output or efficiency of such a trough. Accordingly, the outer trough forms a selfsupporting support construction and includes a conveyor trough which is articulated thereon. The support construction may be designed for wheeled transport, which facilitates exchange or replacement thereof.

An object of the invention is to provide an improved method for charging shaft furnaces, such as blast furnaces, operating under relatively high gas pressures.

Another object of the invention is to provide an improved charging apparatus for charging shaft furnaces, such as blast furnaces, operating under high gas pressures.

A further object of the invention is to provide an improved blast furnace construction, particularly related to the improved charging apparatus and the improved charging method.

Another object of the invention is to provide an improved charge-distributing means for a blast furnace.

A further object of the invention is to provide improved means for conveying charge material from a storage zone to such charge-distributing means.

Another object of the invention is to provide a charge material storage means and associated charge conveying means which are interchangeable with respect to a blast furnace.

For an understanding of the principles of the invention, reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a partial elevation view, partly in section, of one form of blast furnace embodying the invention and illustrating the charge distributing means and the sealed conveying means and storage means which are arranged outside the furnace;

FIG. 2 is a part elevation and part sectional view corresponding to a part of FIG. 1, but illustrating a detail of the connecting line between the charge material storage zone and the furnace zone;

FIG. 3 is an axial sectional view of a furnace head illustrating a modified form of distributing means;

FIG. 4 is a view corresponding to FIG. 3, but taken in a different axial sectional plane;

FIG. 5 is an axial sectional view of a furnace head illustrating a further embodiment of the distributing means;

FIG. 6 is an axial sectional view of a furnace head illustrating a further feature of the invention;

FIG. 7 is an enlarged side elevation view of the line connecting the storage zone and the furnace zone; and

FIG. 8 is a cross-sectional view of the line shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, in the fundamentally novel blast furnace construction embodying the invention there is arranged, within a furnace head 1, a distributing device generally indicated at 2. A central top gas pipe 3 extends upwardly from furnace head 1, and a charge material storage zone 4 is positioned outside and spaced from the furnace. Storage zone 4 is preceded by a sluice chamber 5, and a conveying line 6 connects zone 4 with furnace head 1.

Distributing device 2 is suspended from a rotatable column 7 which extends, in sealed relation, through an attachment 8 of top gas pipe 3. A bracket 9 supports a rotary drive 10 which remains engaged with column 7, to rotate the same, despite longitudinal or axial displacement of column 7. Through the medium of column 7 and drive 10, a bell l1 and an associated pan 12 are slowly rotated during filling of the distributing device 2 with charge material. Vertical or axial displacement of column 7 is effected by a hydraulic piston-type drive mechanism 13 provided with a mechanical relief 13a in the various load positions.

Between storage zone 4 and furnace head 1, connecting line 6 extends in a gasproof channel 14 having, at its furnace end, a valve 15 which can swing outwardly only in the direction of feeding of the material. Valve 15 renders difficult exit from the furnace head 1 or passage 14 of gases collecting in furnace head 1, and hinders heat radiation in the direction of storage zone 4. For the purpose of servicing connecting line 6, or exchanging one connecting line for a new one, there is provided a repair bulkhead 17 whereby furnace head 1 can be closed off at opening 16 after the conveying means 6 has been withdrawn from furnace zone 1 into an extension of channel 14. A blower 150, having an air intake 151, communicates with sealed channel 14, between the furnace head and the storage bunker, to maintain a counterpressure with respect to the furnace zone to prevent outflow of top gas during operation of the furnace.

At storage zone 4, channel 14 connects, in a sealed manner, to the housing of storage zone 4, as indicated at 18. Channel 14 extends across storage zone 4 and has, at its other end, a

' vibratory drive 19 for conveyor means 6. Storage zone 4 is supported by a framework portion 20 which latter is a component part of the blast furnace framework.

The material to be supplied to storage zone 4 is delivered, through a vessel system or through a belt 21, and then through a funnel 22, into sluice chamber 5. Later, and by operation of a conical protective hood 23, the material falls through aperture 24 into storage zone 4. At funnel 22 as well as at aperture 24 there are sealing seats 25. In the example shown in the drawing, an upper sealing plug 26 and a lower sealing plug 27 are provided. Flaps 28 on these plugs are arranged to close the filling aperture of funnel 22 and the opening 24 to storage zone 4. A piston rod 29 is secured to plug 27 and extends through a tubular piston rod 30 secured to plug 26. Piston rod 29 is secured to the piston 31 forming part of a hydraulic piston-cylinder actuator, and a mechanical relief 31a is provided. Piston rod 30 is secured to a piston 32, likewise forming part a hydraulic piston-cylinder actuator, and also provided with a relief 32a. The

reliefs

31a and 32a are designed to retain either of the plugs'in its upper position after the plugs have been lifted by their associated hydraulic actuators.

The invention is not limited to the arrangement shown in FIG. 1 involving the sluice chamber just described, but the objective of the invention can be equally well accomplished by a modified arrangement based on the principle of a separation of the distributing device, which is not provided with a sealing function, from the structural group which performs the sealing off of the furnace but which is arranged outside the furnace head. A particularly advantageous feature of the invention is the favorable arrangement, with respect to temperature, of connecting line 6 in which any gases flowing therethrough are, to that extend, rendered harmless in that their temperature is lowered.

In the embodiment. of the invention shown in FIG. 2, furnace head 1 is positioned on furnacewall 34 and comprises, essentially, a shoulder 35 for top gas pipe 3 and a hood 36 connecting shoulder 35 with furnace wall 34. Rotating column or shaft 7 passes through top gas pipe 3 at 37, and extends downwardly into furnace head I where it is secured to the bell 11. Bell ll and the associated distributor pan 12 form the essential elements of distributing device 2. Column 7 is rotated through a schematically illustrated drive 38, a gear wheel 39 which is fixed against vertical displacement, and a groove and tongue connection 40.

A head 41 of column 7 has guiding engagement in a clamp 42 which is secured to the piston rod of the cylinder 13 of the hydraulic actuator. The hydraulic actuator, including the cylinder 13 and its associated piston rod, is operable to effect axial displacement of column 7. When column 7, together with bell 11 secured thereto, is lowered from position shown in FIG. 2, an outer flange 43 of distributor pan 12 comes to rest on a number of brackets 1a secured to the furnace outer casing so that, at the lower and smaller diameter edge 44 of distributor pan 42, there is formed an annular gap 45 due to the separation of bell downwardly from distributor pan 12. The charge material 46 then present in distributor device 2 falls, at different angles, onto the pile 47 in the furnace, the angles being dependent on the speed of rotation and rate of descent of bell II.

The line connecting the charge material storage zone and the furnace extends into hood 36 of head 1. In the embodiment of FIG. 2, this line is designed as a chute 48 having one end secured, in sealing relation, to hood portion 36 of furnace head 1 and its other end secured, in sealing relation, to a casing or enclosure 49 for the longitudinal conveyor means which, in FIG. 2, is designed as a pivotal or swingable conveyor trough 50. In the same manner as in FIG. 1, and for the same purpose, a blower 150 having an air intake line 151 communicates with chute 48. The vibratory trough 50 has, on its end toward the furnace, a heat-resistant and wear-resistant end piece 51, and trough 50 is driven controllably and adjustably by a vibratory drive 52. The charge material 46 is supplied to trough 50 from a storage bunker 53 which is connected with the outlet of the gasproof sluice chamber (FIG. I), and which has not been shown in FIG. 2.

Chute 48 has connected thereto a gas sealing valve 54 which is opened or closed by a drive 55. When slide valve 54 is open and vibratory conveyor trough 50 is in operation, charge material 46 follows the dash-dot path from storage bunker 53 into distributing device 2. In this operative phase, a small quantity of top gas escaped in the opposite direction through casing 49, storage bunker 53, and finally the gasproof sluice ate.

g This outflow of top gas can be suppressed if, during the times when charging of distributing device 2 is not necessary, trough 50 is stopped or remains stationary and slide 54 is closed by its drive 55. These and other control operations can be effected by a program control shown schematically at 56, and from which a control line 57 leads to vibratory drive 52, a control line 58 leads to slide valve drive 55, a control line 59 leads to the drive 38 for rotating column 7, and a control line 60 to a control device (not shown) for hydraulic cylinder 13.

If the angle of the centerline of chute 48 relative to furnace axis 61 is made sufficiently small, or if the length of chute 48 is made sufficiently small, or if both expedients are adopted, any impingement of charge material 46 onto the chute wall can be prevented and direct injection of the charge material from trough end 51 into distributing device 2 can be attained.

Referring now to FIG. 3, in the embodiment of the invention shown therein furnace head 1 includes a connection to central top gas pipe 3, a radially projecting or inverted frustoconical portion 62 positioned on furnace wall 34, and a hood 63 connecting portion 62 with top gas pipe 3. Hood 63 is formed with a connection or nipple 64 connected to sealed conduit 14, for introduction of charge material 46 into a distributing device generally indicated at 65. A blower 150, having an air intake 151, communicates with sealed conduit 14.

Distributing device 65 comprises essentially a distributor pan 12 in the form of an inverted truncated cone, which is concentric with the axis of the furnace, and which is rotatable, from a point outside the furnace, by drive rollers 66 engaged beneath an out-turned flange on the upper end of distributor pan 12, and an axially displaceable closure part or portion 67 which is also concentric with the furnace axis, is rotatable, and has the form of a truncated hollow cone. Normally, closure part or portion 67 has its larger diameter edge resting on the lower edge of pan 12 through the medium of a packing ring 76. In this position of the parts of the distributing device 65, the rolls of rotary drive 66, which are distributed around the circumference of pan 12, support distributor pan 12 as well as closure part 67 and the charge material 46 contained in these two parts. The shafts 68 of the drive rolls are rotatably mounted at 69 and are axially displaceable relative to the portion 62 of the furnace top.

In the relative position of the parts shown in FIG. 3, charge material 46 can be supplied to the distributing device along the dash-dot line 70 through filling pipe connection or nipple 64. When the desired amount of charge is present in distributing device 65, the weight of the distributing device is supported, at the outer edge 71 of distributor pan 12, by lift devices 72 shown in FIG. 4 and which are distributed around the circumference of distributor pan 12. By means of devices 72, distributing device 65 is raised slightly until the rolls of the rotary drive 66 can be axially displaced from beneath edge 71 of distributor pan 12, together with the shafts 68. In FIG. 3, the axis or center line of a lift device 72 is indicated at 73.

Subsequently, distributor pan 12 is lowered by lift devices 72. During such lowering, and after a short downward axial movement of pan 12, a conical bead 74 of closure part 67 comes to rest on one or more mounts fastened to furnace hood 63. With further lowering of distributor pan 12, the lower edge of pan 12 is disengaged from the lower edge of closure part 67, having the packing ring 76, permitting charge material 46 to flow out along the dashdot line 77, of FIG. 4, onto the pile 47 in furnace 1.

As soon as the contents of distributing device 65 have been evacuated in this manner, distributor pan 12 is again moved upwardly into contact with closure part 67, along packing ring 76, by lift devices 72. When pan 12 thus engages packing ring 76, closure part 67 is also lifted and disengaged from mounts 75. Such raising of the distributing device is continued until drive rolls 66 can again be displaced axially inwardly under the edge 71 of distributor pan 12, so that the distributing device can again be set down onto the drive rolls.

In the embodiment of the invention shown in FIG. 3, the distributing device extends relatively far axially outwardly relative to the circumference of furnace 1, so that packing ring 76 is arranged approximately in prolongation of the inner wall of the furnace. This gives the furnace head 1 the radially projecting part 62.

In all operative states, a practically unhindered outflow of the top gas along the arrowed lines 78 into top gas pipe 3 takes place. An appreciable loss of top gas through the nipple 64 and sealed conduit 14 is suppressed at the closed packing ring 76 and in the filled distributing device 65 by a labyrinth 79, as well as by other means. A pressure gate valve or sluice of conventional design may be connected to nipple 64. The curvature of line 77 or of the rotational surface provided by the generatrix 80 can be influenced by a deflecting portion 81 at the lower end ofdistributor pan 12.

In FIGS. 3 and 4, packing ring 76 is radially inwardly a small distance from the inner wall of furnace 1. By this arrangement, the crest of pile 47 is shifted further toward furnace axis 61 in accordance with a changed course of the drop line 77.

In FIG. 4, lift device 72 is shown, in section and diagrammatically. The lift device consists essentially of a cylinder 82 whose housing is supported by struts 83 and furnace hood 63. Piston rod 84 of cylinder 82 extends, at 85, through furnace hood 63, and is provided at its lower end with a clamp 86 embracing the edge 71 of the distributor pan. The pressure medium line of cylinder 82 is indicated at 87. For the sake of completeness, there is shown, in FIG. 4, an axis 88 of shaft 68 of rotary drive 66, but which is actually offset perpendicular to the plane of the drawing at an angle.

Referring to FIG. 5, a furnace is illustrated as having the central top gas pipe 3 and a hood 89 forming the furnace head. Within the lining 34 of the furnace, there is a pile of charge material 47 having a pile profile 93 comprising

concentric waves

90, 91 and 92.

In the interior of hood 89, there are secured furnace brackets 94 which either encircle or are distributed around the circumference of the hood. The out turned upper edge 96 of a distributor pan 95 can rest on these brackets. The lower smaller diameter end of the pan 95, which has substantially the shape of a hollow truncated cone, can be brought into sealing contact with a lower'section 98 of a closure part 99 likewise having the overall form of a hollow truncated cone and further including a central section 100 and an upper section 101..

Sections

98, 100 and 101 are suspended, by means of

respective carrying devices

102, 103 and 104 from

respective drive shafts

105, 106 and 107. Drive shaft 105 may be solid or may be tubular, and drive

shafts

106 and 107 are telescoped over and are coaxial with shaft 105. The outermost hollow shaft 107 is surrounded with wear blocks 108 for protective purposes.

Shafts

105, 106 and 107 pass through top gas pipe 3 at a point which has not been shown and where there is provided a sealing packing. Each shaft has a respective drive (not shown) for lifting and lowering the shaft and preferably is provided with a mechanical relief (also not shown) to fix the axial position of the respective shaft to relieve the associated drive. In addition, drive shaft 105 is provided with a rotary drive 105a coupled to shaft 105 through a splined shaft profile 109, thereby permitting axial displacement of shaft 105 relative to drive 105a.

Each of the carrying devices or supports 102, 103 and 104 comprises several struts distributed around the circumference of the associated

section

98, 100 or 101. In order to protect the lower ends of

shafts

105, 106 and 107, a rotation-symmetrical guide body 110 is fastened to the struts of the lower support 102, and guide body 110 is formed, in its upper part, with longitudinal slots for the upward and downward movement of the struts ofsupports 103 and 104.

In the embodiment of the invention shown in FIG. 5, it is assumed that

sections

98, and 101 do not rotate relatively to each other. If such relative rotation is to be permitted, guide body must be designed in a different manner in its upper part and be composed, for example, of several parts secured to the respective supports. At its bottom end, guide body 110 is formed with an aperture 112 shielded by a closure body 111, this aperture being provided for the discharge of dust and other material which may collect in the interior of guide body 110. Body 110 protects

shafts

105, 106 and 107 from the direct action of the furnace atmosphere and from dust. The charge material is introduced, by any desired conveying means 113 extending through sealed conduit 14, in the direction of the arrow 114 and through an aperture 115 in furnace hood 63 into the furnace head.

By rotation of drive shaft 105, charge material 46 is distributed either uniformly or in locally different quantities on the circumference of the distributing device formed by distributor pan 95 and closure part 99. Depending on the requirements of pile 47, charge material 46 can be let out of the distributing device, by lifting of upper section 101, in the direction of an arrow 116 for formation of the concentric wave 90. Alternatively, by lifting of section 100, the material may be discharged along the direction of arrow 117 for formation of concentric wave 91. Finally, by lowering of lower section 98 relative to distributor pan 95, which is then resting on furnace brackets 94, the material is discharged in the direction of an arrow 118 for the formation of concentric wave 92. Depending on the velocity of axial movement of

sections

98, 100 and 101, there will be formed

concentric waves

90, 91 and 92 with more or less deep valleys or troughs between the individual waves to provide the pile profile 93. Thereby, there is provided a wide choice in the formation of the actual pile profile 93.

Flow of the top gas to pipe 3 through the annular channel formed between guide body 10 and closure part 99 is facilitated in that the lower part 119 of furnace hood 63 slopes radially inwardly of the furnace in the direction of lower section 98 of closure part 99. By virtue of this, only a comparatively small quantity of top gas escapes through the gap 120 between distributor pan 95 and furnace hood 63.

' In the embodiment of FIG. 6, a furnace, having a lining 34, is provided with a hood 121 through which the top gas is drawn off in a suitable manner which has not been illustrated. Through the hood 121, there pass, in sealing relation, plural furnace brackets 122, preferably three, distributed around the circumference of the hood. These furnace brackets 122 carry a distributor pan 123, and are vertically displaceable as indicated by the double arrow 124. In FIG. 6, the uppermost position of furnace brackets 122 is shown in solid lines and the lowermost position in broken lines. A distributor pan 123, in the form of a hollow truncated cone, has its lower edge resting on a closure part 125, also in the form of a hollow truncated cone. Closure part 125 is suspended, by means of a support 126, from a vertically and axially displaceable and rotatable drive shaft 127. Alternatively, closure part 126 may consist of several sections, similar to the arrangement shown in FIG. 5. When closure part 125 is lowered from the position shown in FIG. 6 in solid lines, the out-turned upper edge of distributor pan 123 comes to rest on the furnace brackets 122, and charge material 128 leaves the distributing device, to form a concentric wave 129 on pile 47, in the direction of an arrow 130. In a like manner, upon lowering of closure part 125 from the position shown in broken lines in FIG. 6, the charge material flows along a path indicated by an arrow 131 to form a concentric wave 132, of smaller diameter than wave 129, on pile 47. At suitable intermediate positions of furnace brackets 122, the trough between

waves

129 and 132 can be filled.

FIG. 7 illustrates connecting line 6 of FIG. 1 on a larger scale and in greater detail. Referring to FIG. 7, conveyor means 6a comprises a thrust conveyor 133 consisting, essentially, of two troughs which are relatively displaceable one inside the other in a longitudinal direction. The inner trough is J11 drivable, for example, with the vibratory drive 19 of FIG. 1, and the drive permits regulating the drive stroke as to velocity and magnitude. The quantity of material conveyed can therefore be regulated.

FIG. 8 illustrates the cross section of the connecting line 6 comprising the two telescoping troughs. The outer trough 134 is formed with sidewalls 135 and a bottom wall 136, and is designed as a self-supporting construction, whose strength is attained, in particular, by the upper chords 137. Reinforcement of the support construction is enhanced by internal spars or timbers 138, which are illustrated in broken lines so as to be able to illustrate better the suspension ofinner trough 139.

Inner trough 139 has junctions or suspension points 140 which receive the heads 142 of loose swing rods 14]. Joints or bearings 143 are fastened to walls 135 of trough 134, and joints or bearings 143 receive the upper ends of rods 141 in guiding relation. These rods, through the joint heads 142, serve to carry the load of inner trough 139 containing charge material 46. The vibratory drive 19 of FIG. 1 acts in a direction perpendicular to the plane of the drawing of FIG. 8, so that inner trough 139 is continuously reciprocated relative to the observer, the charge material 46 migrating in the direction of the furnace due to a more rapid backward or retracting stroke of trough 139.

The support of connecting line 6 advantageously is made as a light construction and receives in its interior thrust conveyor 133. The latter itself has an advantageous construction due to the provisions of the lower chord 136, lateral walls 135, upper chords 137 and inner spars 138. Connecting line 6 forms a closed box of the form shown in FIG, 7, encircling spars or ties 144 extending completely around this closed box to attain a desired stiffness. The box is also provided with suspension means 145 for securing connecting line 6 to the frame of the furnace.

Charge material 46 impinges on inner trough 139 in the direction of arrow 146 of FIG. 7, without free fall, and is discharged onto the distributing

device

2,99, or 65, illustrated respectively in FIGS. 2 through 6. The discharge direction is indicated by the arrows 147 of FIG. 7.

In accordance with the invention, the support construction, comprising inner trough 139 and outer trough 134, may also be designed to be movable. For this purpose, the support construction is provided with wheels 148 running on rails 149. Thereby, the support construction, including the inner and outer troughs, can be moved out of the connecting line 6.

While a sluice chamber, precedingand communicating with storage zone 4 which, in turn, communicates with the inlet end of sealed conduit 14, has been illustrated only in FIG. 1, it should be understood that such a sluice chamber is associated with the storage zone connected to the sealed conduit in each of the embodiments of the invention. The sluice chamber has been omitted, except for illustration in FIG. 1, solely for the purpose of simplifying and clarifying the illustration of the invention.

What is claimed is:

l. A shaft-type furnace installation comprising, in combination, a blast furnace having a pressure-sealed furnace zone and a furnace head; charge distributing means positioned in said head; at least one storage bunker positioned outside said blast furnace, each storage bunker including a pressure-sealed storage zone; hermetically sealed conveyor means connecting each storage zone to said pressure-sealed furnace zone to deliver charge material to said distributing means; and a sluice chamber preceding and communicating with each storage zone.

2. A shaft-type furnace installation, as claimed in claim 1, in which said blast furnace includes a furnace shell; said distributing means comprising an upwardly converging frustoconical rotatable bell; means mounting said bell for downward displacement for discharging material into the pressure-sealed furnace zone therebeneath; a downwardly converging frustoconical pan having its lower edge engaging the peripheral surface of said bell and receiving the charge material from said conveyor means, said pan being movable freely relative to said bell; and support brackets positioned around the circumference of said furnace shell and engageable with the upper edge of said pan upon lowering of said bell to hold said pan stationary while said bell is lowered.

3. A shaft-type furnace installation, as claimed in claim 1, in which said hermetically sealed conveyor means includes a vibratory conveyor trough.

4. A shaft-type furnace installation, as claimed in claim 1, in which said hermetically sealed conveyor means includes an hermetically sealed enclosure which is sealed in a gastight manner with respect to said furnace zone.

5. A shaft-type furnace installation, as claimed in claim 1, including a blower connected to said hermetically sealed conveyor means between said storage bunker and said furnace head and maintaining, in said hermetically sealed conveyor means, a counter pressure opposing the pressure in said furnace zone.

6. A shaft-type furnace installation, as claimed in claim 1, in which each storage bunker and its associated sluice chamber forms a structural unit; and guide means mounting each structural unit for movement of the same into operative position, whereby said structural units are interchangeable.

7. A shaft-type furnace installation, as claimed in claim 1, in which said hermetically sealed conveyor means has a discharge end spaced from said furnace; and a gas-proof connecting line connecting the discharge end of said conveyor means to the furnace at a point just above said distributing means.

8. A shaft-type furnace installation, as claimed in claim 7, in which said connecting line comprises a chute inclined downwardly toward the axis of said blast furnace.

9. A shaft-type furnace installation, as claimed in claim 1, including a gas shutoff valve interposed in said hermetically sealed conveyor means; first driving means connected to said conveyor means; second driving means connected to said valve; and control means connected to both said driving means and controlling the same conjointly and as a function of the charging cycle.

10. A shaft-type furnace installation, as claimed in claim 1, in which said distributing means includes a downwardly converging frustoconical distributor pan; means mounting said pan for rotation and axial displacement; and a circular cross section closure element having a lower peripheral edge resting, in sealing relation, against the lower peripheral edge of said distributor pan in the filling position of said distributing means; and retaining means fixedly mounted on said furnace head and engageable with the upper peripheral edge of said closure element upon downward axial displacement of said distributor pan to restrain said closure element against downward movement to open said distributing means.

1 1. A shaft-type furnace installation, as claimed in claim 10, in which said blast furnace includes a gas exhaust pipe extending from said furnace head; said closure element comprising a hollow truncated cone converging upwardly toward said gas pipe; and a packing ring extending around the periphery of the base of said truncated cone and engageable with said distributor pan.

12. A shaft-type furnace installation, as claimed in claim 1, in which said distributing means comprises at least two concentric circular cross section sections; a respective axially displaceable and rotatable drive shaft supporting each section, said drive shafts being telescoped one within the other; respective raising and lowering means connected to each drive shaft to raise and lower the same; and driving means commonly connected to said shafts to rotate the same conjointly.

13. A shaft-type furnace installation, as claimed in claim 12, in which the separation planes of said sections extend normal to the common axis of said drive shafts.

14. A shaft-type furnace installation, as claimed in claim 12, in which said distributing means further includes a truncated conical downwardly converging distributor pan having its lower edge resting on the lowermost section, for receiving the trough to displace the same; and control means operatively associated with said driving means to vary the speed and amplitude of the movement of said inner trough.

16. A shaft-type furnace installation, as claimed in claim 15, in which said outer trough is in the form of a self-supporting support construction; and a conveyor trough articulated to said support construction for swinging relative thereto.

17. A shaft-type furnace installation, as claimed in claim 16, including wheels supporting said support construction.

i i l

Claims

1. A shaft-type furnace installation comprising, in combination, a blast furnace having a pressure-sealed furnace zone and a furnace head; charge distributing means positioned in said head; at least one storage bunker positioned outside said blast furnace, each storage bunker including a pressure-sealed storage zone; hermetically sealed conveyor means connecting each storage zone to said pressure-sealed furnace zone to deliver charge material to said distributing means; and a sluice chamber preceding and communicating with each storage zone.

11. A shaft-type furnace installation, as claimed in claim 10, in which said blast furnace includes a gas exhaust pipe extending from said furnace head; said closure element comprising a hollow truncated cone converging upwardly toward said gas pipe; and a packing ring extending around the periphery of the base of said truncated cone and engageable with said distributor pan.

14. A shaft-type furnace installation, as claimed in claim 12, in which said distributing means further includes a truncated conical downwardly converging distributor pan having its lower edge resting on the lowermost section, for receiving the charge material; said blast furnace including a furnace shell; and support means on said furnace shell engageable with the upper edge of said distributor pan upon lowering of said sections to restrain the support pan against downward movement with said sections; said support means being mounted for displacement relative to said distributor pan.

15. A shaft-type furnace installation, as claimed in claim 1, in which said hermetically sealed conveyor means includes a thrust conveyor comprising inner and outer relatively displaceable troughs; driving means connected to said inner trough to displace the same; and control means operatively associated with said driving means to vary the speed and amplitude of the movement of said inner trough.