US3796419A

US3796419A - Charging apparatus for shaft furnaces

Info

Publication number: US3796419A
Application number: US00134203A
Authority: US
Inventors: T Werner; K Roenick
Original assignee: MC KEE A AND CO
Current assignee: MC KEE A AND CO
Priority date: 1971-04-15
Filing date: 1971-04-15
Publication date: 1974-03-12
Anticipated expiration: 1991-03-12
Also published as: CA971359A

Abstract

An apparatus for charging material into a shaft furnace, such as a blast furnace, having a generally vertical axis. Several port means are spaced around the axis and mounted on the upper portion of the furnace portion above two furnace bells in superposed stationary hoppers. Each of the port means has an upwardly open mouth, and individual valve means for closing the port means gas tight and for opening the port means independently of other port means so it can provide an unimpeded flow of material into the furnace. An externally supported and driven chute is mounted above all port means for rotation about the axis. The chute has a lower discharge opening positionable over the mouth of selected port means to discharge material into the mouth so that material will pass from the chute into the furnace when the port means is open, and the chute has an upper opening adapted to receive charge material deposited in the chute. A stationary hopper is mounted above the chute to receive charge material from a suitable material supply means such as a skip car or conveyor. The externally supported and driven chute is not enclosed in any hopper.

Description

United States Patent Werner et al.

[1 3,796,419 1451 Mar. 12, 1974 CHARGING APPARATUS FOR SHAFT FURNACES V [75] inventors: Tage Werner, Rockey River; Karl W. Roenick, Fairview Park, both of Ohio [73] Assignee: Arthur G McKee & Company, Cleveland, Ohio [22] Filed: Apr. 15, 1971 [21] App]. No.: 134,203

[52- us. c1....., 1266/27, 214/36 511 1m. c1 r271) 11/12 [58] Field of Search 214/37, 36; 266/27 [56] 1 References Cited UNITED STATES PATENTS 3,542,219 11/1970 Yoshioka 214/37 3.077.274 2/1963 Kitzrow 266/27 938,572 11/1909 Geuze ..l 214/37 3,476,374 ll/l969 Colijn 214/37 3,598,257 8/1971 Pantke'm. 266/37 3,302,805 2/1'967 "Tsutsumi. 214/37 3,706,387 l2/l972 Tokarz ..-I 214/37 0r FirmBosworth,- Sessions, &

ABSTRACT An apparatus for charging material into a shaft furnace, such as a blast furnace, having a generally vertical axis. Several port means are spaced around the axis and mounted on the upper portion of the furnace tionable'over the mouth of selected port means to discharge material into the mouth so that material will pass from the chute into the furnace when the port means is open, and the chute has an upper opening adapted to receive charge material deposited in the chute. A stationary hopper .is mounted above the chute to receive charge material from a suitable mate rial supply means such as a skip car or-conveyor. The externally supportedand driven chute is not enclosed in any hopper. r

32 Claims, 17 Drawing Figures PAIENTEM: I 2 m4 sum 1 BF 6 BY 1441a Mpaav/a/ HMWACQW CHARGING APPARATUS FOR SHAFT FURNACES DISCLOSURE OF THE INVENTION Field of the Invention This invention relates to apparatus for charging material into a shaft furnace, and more particularly to apparatus for charging particulate burden material into a shaft furnace such as a blast furnace, to provide desired 1 amounts and distribution of the material while preventing gas leakage from the furnace, even if the furnace operates under severe conditions as occur when the furnace is of large diameter and has high internal gas pressure.

BACKGROUND OF THE INVENTION To achieve greater production and increased efficiencies and economies in blast furnace construction and operation, recent blast furnace designs have trended toward furnaces of substantially larger diameters and 'the use of substantially higher internal top pressures than have been heretofore common. In new furnaces being designed or built, top pressures range as high as 30. pounds per square inch, hearth diameters range up to 50 feet or more, and iron productions up to 6,000 tons per day or higher. These factors of high gas pressure, large furnace size, and large productions have imposed severe problems in the design and operation of the charging apparatus of such furnaces, to permit the charging of the required large quantities of burden material in the desired distribution over the large furnace cross sectional area of such a furnace, while preventing leakage of the gas at high pressures.

DISCUSSION OF PRIOR ART For example, these factors cause great problems with the type of charging apparatus heretofore widely used, wherein a hopper the bottom of which is closed by a small bell is rotatably mounted above a larger hopper the bottom of which is closed by a large bell, the rotatable small bell hopper being sealed at its circumference to prevent internal furnace gases from leaking out. Whenhigher gas pressures are used, tendencies toward leakage are intensified. The problem of gas leakage is also accentuated when in large capacity furnaces the diameter of the small bell hopper is enlarged to permit handling at a suitable rate of the large amounts of burden material that must be charged into the furnace.

Various proposals have been made to overcome these problems, mostly involving eliminating rotation of the small bell hopper. In one design developed recently, both the large bell and small bell hoppers are non-rotatable and respectively closed by large and small bells, and a rotatable chute is mounted inside the small bell hopper to deposit charge material at the desired lateral position on the small bell. Above the chute and in the top of the small bell hopper, there are one or more valve that can be closed to seal furnace gas, and can be opened to permit burden material to be discharged into the chute while it is rotating or while it is stationary to discharge at a desired location on the small bell.

In such apparatus, the chute is supported and driven from a rod that surrounds the two bell rods. Since triple which is rotatable, a complicated construction results that is not only expensive to build but also is subject to substantial maintenance problems. There is always danger of breakdowns because of heat and dust which can cause jamming of the chute in a position where it cannot be moved to accomplish the desired depositing of the material at different locations around the furnace interior, so that the furnace cannot be successfully operated. Moreover, the chute can be reached only with great difficulty for maintenance repair or replace- 0 ment, since it is inside the hopper.

In another recently developed design, there are stationary small and large bell hoppers, and another stationary hopper, fixed above the small bell hopper, that has branched discharging ports at its bottom. Each of these discharging ports is closed by a material cutoff valve and gas cutoff valve. Each discharging port can open into the fixedsmall bell hopper when its valves are open. A rotatable chute is mounted within the upper portion of this branched upper hopper. In operation, burden material from the rotatable chute, usually while the chute is rotating, is deposited in the branches of the upper hopper, being supported by the material cutoff valves. At the appropriate time, both the material cutoff and gas cutoff valves of a selected hopper branch and port are opened to permitthe discharge of the material into the small bell hopper to deposit material on the small bell at the desired location.

While in this design the rotatable chute may be supported and rotated by means located externally of any hopper and held thereby several cutoff valves imposes difficulties and disadvantages because of expensive complications in providing and operating several material cutoff valves, and because these valves can jam due to the material supported by them. Moreover, the lower end of the chute is in the hopper at all times and if it should jam, clog, or otherwise become damaged, it is a difficult, time-consuming, and costly operation to get access to that portion of the chute for correction action. Moreover, the operation of the material cutoff valves and gas cutoff valves must be carefully coordinated to prevent burden material discharging from the hopper from striking and damaging or destroying the gas cutoff valve if the material cutoff valve should be opened in a particular branch port before .the gas cutoff valve.

SUMMARY OF THE INVENTION It is an object of the invention to provide apparatus for charging material into a shaft furnace such as a blast furnace, that will operate efficiently in small or large furnaces to charge desired quantities of particulate burden material into the furnace in any of a wide range of distribution patterns across the furnace, while the furnace is operating under gas pressures as high as any contemplated at present or the foreseeable future. It is a further object of the invention to avoid the problems and disadvantages of prior art apparatus such as those described above.

The present invention provides apparatus for charging material into a shaft furnace having an upper furnace portion with a generally vertical axis, a plurality of means providing ports mounted on the upper furnace portion and spaced around the axis, each of the port means having an upwardly open mouth, valve means for closing each the port means in gas sealing relation and for opening each the port means indepen dently of other means to permit flow of material through the port unimpeded by the valve means, an externally supported and driven chute mounted above the port means for rotation about the axis, the chute having a lower discharge opening adapted to be moved over the mouth of a selected port means and to discharge material into the mouth of such port means so that the material will pass by gravity from the chute into the furnace, preferably into a bell hopper such as a small bell hopper above a large bell hopper, when the valve of such port means is open, the chute having an upper opening adapted to receive charge material that discharges through the lower chute opening, and means for depositing material into .the upper opening of the chute. The chute is not enclosed in any hopper, and is supported and rotated externally of any hopper so that the chute is readily accessible for maintenance and repair. I

There is no rotatable hopper that can provide gas sealing problems. There is no chute contained within any hopper that prevents access tothe chute only with difficulty. There are no valves required to hold material discharging from thechute, since the material entering the chute discharges directly through a selected port means and into the furnace, as into a bell hopper, when the port means'is open; and the valve means in the port means need only be used for sealing against escape of gas.

Consequently, apparatus can be made more simply than prior apparatuses. The problems of sealing against high gas pressures are simplified because there is no member such as a hopper of large circumference that must be sealed against gas, but several considerably smaller valves able to withstand readily any force caused by high furnace pressure. By providing a proper number of port means, preferably at least four, and proper cycling of the position of the chute, the desired distributions of material within the furnace can be readily achieved even though the furnace has a large cross section and diameter.

Moreover, apparatus embodying the invention can be made of sufficiently low overall height so it can be installed on existing furnaces to replace existing charging equipment without major alterations to other top structure.

BRIEF DESCRIPTION OF THE DRAWINGS These and other advantages of the invention will become apparent from the following description in connection with the accompanying drawings in which:

FIG. 1 is a vertical section through a blast furnace top illustrating a preferred type of furnace charging apparatus embodying the invention, utilizing skip car material supply means;

FIG. 2 is a plan section along line 22 of FIG. 1 to a larger scale, showing in broken lines the lower portion of the chute;

FIG. 3 is a section along line 3-3 of FIG. 2 and to the same scale, showing'the open mouth of one of the port means and how the open mouths are included in an annular shielding member that prevents spillage of material discharging from the lower end of the chute between the open mouths or alongside the mouths;

FIG. 4 is a section along line 4-4 of FIG. land to the same scale as FIG. 2, showing in plan the fixed upper hopper for receiving material from a skip car discharging it into the chute;

FIG. 5 is a side view of the upper hopper of the apparatus of FIG. 1, to the scale of FIGS. 2-4, showing how the lower portion is shaped to fit into the upper end of the chute;

FIG. 6 is a somewhat diagrammatic view showing means for actuating one of the gas valves in one of the port means;

FIGS. 7 to 12 inclusive, to a smaller scale than FIG. 1, show steps in an illustrative process of operating the apparatus of the preceding figures;

FIG. 13 is a vertical section of another form of apparatus embodying the invention, to the same scale as FIG. 1, utilizing a conveyor'as material supply means;

FIG. 14 is another embodiment of the invention showing means for supplying and removing gas from the bell hoppers;

FIG. 15 is a partial plan view, to the scale of FIGS. 24, showing another type of means operating between the lower end of the chute and the port means for shielding against escape of material passing from the chute to the port means;

FIG. '16 is a section along line 16-16 of FIG. 15; an

FIG. 17 is a section along line 17-17 of FIG. 16.

DESCRIPTION OFPREFERRED EMBODIMENTS manner. Small bell 6 is supported, lifted and lowered inknown manner by a tubular bell rod 8 slidably surrounding bell rod 7 in known manner. The bells do not rotate while they close their respective hoppers; if desired, either or both may be rotated when lowered in hopper opening position, as to equalize wear. Known means, not shown, are provided for actuating the bell rods 7 and 8 to raise and lower their bells as required, and for rotating the bells if desired when they are lowered.

The top wall 11 closing the small bell hopper 5 has a tubular portion 12 surrounding tubular bell rod 8 and extending upwardly to a location generally above the charging apparatus. The axes of the rods and portion 12 coincide with axis A. To prevent escape of furnace gas past the bell rods 7 and 8 and tubular portion 12, sealing means 13 operates between tubular portion 12 and reciprocable small bell rod 8, and sealing means 14 operates between bell rod 8 and bell rod 7 of the large bell. Since these sealing means may be conventional no further description is required.

An upper fixed hopper 15, supported by frame members l6, 17 at the top of the furnace, is adapted to receive particulate burden material to be charged into the furnace, from a suitable source of supply such as conventional skip car 18 traveling on tracks 19.

Preferably, as shown in FIG. 4, hopper 15 is rectangular in plan and is adapted to receive material from two adjacent skip cars 18 alternately traveling up to the hopper to discharge material into it. The lower portion 21 of hopper 15 is shaped (FIG. 5) to be of generally circular configuration, defining a generally octagonal bottom opening 22 in the illustrated embodiment, so lower portion 21 can fit and extend within the flared upper portion 23 of a chute 24. Chute 24 is rotatably mounted about axis A and has a tubular portion 25 that surrounds tubular portion 12 of bell hopper and the bell rods; and portion 12 extends upward through hop per opening 22 to locations above hopper to prevent entrance between

portions

12 and 25 or into sealing means 13 and 14 of burden or other material that could damage these portions or impair rotation of the chute.

Chute 24 is supported by and fixed to an annular member 26 that is supported by three or more tapered rollers 27 rotatably mounted about horizontal axes on blast furnace frame 28. Three or more side rollers 29 rotatably mounted about vertical axes on frame 28 keep the chute at all times centered about axis A. Chute 24 is rotated as required by a ring gear 31 fixed to the chute and meshing with a spur gear 32 driven by a motor 33 energized by known means not shown.

Chute 24 has an inclinedlower portion 34communieating with upper flared portion 23and having a lower end that is offset to a side of axis A and tubular portion 25 extending upwardly through the chute. The lower end of the chute terminates in a discharge opening 35.

A plurality, preferably at least four, and six in the illustrated embodiment, of port means 36 are disposed around the axis A and fixed gas-tight to the top wall 1 1 of the small bell hopper 5 of the furnace. Each of these port means comprises a housing portion 37 (FIG. 1) having an upwardly open mouth 38, the mouths all being preferably the same size and equidistant from axis A; preferably they are also equiangularly spaced around axis A (FIG. 2). Each port means 36 includes a gas sealing valve means 39 mounted in housing 37 and adapted to close the lower end of a passage 40 the upper end of which terminates in the mouth 38. In the illustrated embodiment, each valve 39 comprises a stationary valve seat 41 at the lower end of passage 40 and an upwardly convex movable closure member 42 (FIGS.'1 and 6) that is pivotally mounted by lug means 43 on an arm 44 that is fixed to a horizontal rotatable shaft 45 that extends to theoutside of housing portion 37 of the port means but is sealed against gas leakage from the housing by conventional means. While the shaft may be rotated as required to open and close the valve 39 by various known means, that shown (FIGS. 1 and 6) comprises a gear segment 46 rigidly mounted on the shaft and engaging a gear 47 that is rotated as required by a motor 48 which may be a conventional type energized as required by known means, requiring no description. If desired, the valve seat 41 or the upper surface of closure member 42 may be covered in whole or in part where they meet with sealing or gasket material such as synthetic rubber to aid in providing a tight gas seal; an annular layer 49 of such material is shown on closure member 42 in FIG. 6. Use of such sealing h passage 4 l and heneethe mouth 38 of the port means and provides a gas tight seal even at high pressures in the furnace, the force on member 42 exerted bythe gas pressure aiding in keeping the valve closed gas tight;

and when the arm 44 is turned to the position shown in broken lines in FIG. 1, all portions of the valve completely clear the passage and permit an uninterrupted and unimpeded flow of burden material from chute 24 through the port means into small bell hopper 5; and any sealing layer 49 is not contacted or damaged by the charge material.

Each of the valves is operable independently of the other valves, and the valves can be readily made so that when allvalves are closed, even if the pressure in the small bell hopperis equivalent to a high furnace pressure, there is no gas leakage.

Each mouth 38 of each port means 36, and the opening 35 at the lower end of the chute are so shaped that when chute opening 35 is aligned with a mouth, it. substantially coincides with the mouth as to area and shape and facilitates unimpeded flow of material without spillage from the chute into the mouth, past the open valve, andinto the small bell hopper.

However, further to insure against spillage of any burden material being charged, the mouths of all port means and the bottom of chute 24 open into shielding means 51 (FIGS. 1, 2, 3), which in theembodiment of FIGS. 1-12 comprises an annular channel portion having upstanding outer and

inner side walls

52 and 53, and a bottom portion made up of inclined walls 54 and 55 (FIGS. 2 and 3) that merge with and form parts of the mouth 38 and also terminate at their upper edges in ridges 56 formed by adjacent walls of adjacent mouths.

As is apparent from FIGS. 1, 2 and 3, when the lower end of the chute 24 is moved so its lower end opening 35 is over a mouth 38, even if the chute should not be perfectly aligned with the mouth, none of the material discharged from the chute will spill out over outer wall 52 or inner wall 53, or, because of ridges 56 and walls 54 and'55, into an adjacent mouth.

An illustrative mode of operation of the thus described charging apparatus of FIGS. 1-6 is illustrated by FIGS. 7 to 12. As shown in FIG. 7, chute 24 while empty and while no skip car is discharging into fixed hopper 15, is turned to a selected one of the port means 36 and positioned stationary so its lower end is aligned with the mouth of such port means. All valves 39 and both the large and small bells are closed at this time. Preferably, the small bell hopper 5 had been filled as through pipe 57 and valve 58 with clean gas, such as steam, clean .blast furnace gas, or nitrogen, at a pressure approximately equal to or even slightly exceeding the gas pressure in the furnace. The large bell hopper contains gas at furnace pressure.

Thereafter, the gas pressure in the small bell hopper is relieved through pipe 59 by opening valve 60. Then, as illustrated by FIG. 8, the gas seal valve 39 of the selected port means is opened and charge material M from a skip car 18 is discharged into hopper 15 from whence it passes by gravity through chute 24 through the open port means 36 into small bell hopper 5 where it is retained by closed small bell 6.

Thereafter, (FIG. 9) the opened gas seal valve 39 is closed and small bell hopper 5 is pressurized with clean gas through pipe 57 and valve 58.. The small bell 6 is then lowered to discharge material M in hopper 5 into hopper 3 onto large bell 4. The above steps may be carried out one or more times as desired or required by the charging cycle; in the process of which a portion is illustrated by FIG. 9, several skip car loads of charge material are being deposited in the large bell;

After the desired amount of charge material has been deposited on the large bell, and after the small bell has been raised to its hopper closing position the large bell is dropped as shown in FIG. 10 to deposite the burden material M in the furnace. During all of this time the large bell hopper 3 has contained gas under the pressure of the furnace gas below the large bell. In the illustrated process this gas in the large bell hopper is furnace gas introduced by conventional means not shown.

During or after dropping of the large bell, and while no charge material is beingdeposited into upper hopper 15, the empty chute 24 is turned to and aligned with the mouth of another selected port means 36 as shown in FIG. 11, the location being predetermined by a desired pattern of depositing burden material in the furnace. I

Thereafter, (FIG. 11) after the gas pressure in the small bell hopper has been relieved through pipe 59 and valve 60 and while the large bell hopper contains gas at furnace pressure, the gas cutoff valve 39 associated with the port means 36 with which the chute 24 is now aligned is opened and chargematerial from a skip car 18 is discharged into upper hopper from which it passes through chute 24 and through the selected port means 36 and into the small bell hopper 5 onto small bell 6. After this formerly opened valve 39 is closed and the small bell hopper is pressurized with clean gas, small bell 6 is lowered and material is dropped onto the large bell as described above in connection with FIG. 9.

The cycle may be repeated as many times as desired until the desired amount of material is deposited on the large bell 4. Thereafter, after all valve means 39 have been closed, the small bell hopper is pressurized with clean gas to match the pressure in the large bell hopper which contains gas at furnace pressure; the large bell is then dropped as shown in FIG. 12 to deposit its charge material M in the furnace.

The cycles described above may be repeated during the furnace campaign with all port means in desired sequence to achieve the desired distribution of desired charge material in the furnace. The chute is moved to a selected port means while empty and material then discharged into the chute while the associated gas sealing valve is open so the material can pass to and through the port means and deposite on the small bell while it closes its hopper. In the above described procedure, the small bell hopper is pressurized with clean gas at all times except when a valve 39 is to be and is opened, and the large bell hopper is under furnace pressure at all times; the small bell holds the gas pressure in the furnace only when gas seal valve 39 is open, and the large bell at no time holds the gas pressure in the furnace since the gas pressures on both sides of the large bell are always the same.

Of course, other modes of operation of the above described apparatus are possible by suitable modification of the above processes, including those in which the chute is rotated after each skip car load of material is deposited .in the apparatus; or those in which more than oneskip car load of material is deposited on the small bell before it is dumped, in which case the selected valve means 39 can be kept open until all desired loads are deposited on the small bell.

In all of these processes, advantages are provided because differences and duration of differences in gas pressures above and below the bells are minimized, thus minimizing leakage of dust laden gas past the bells that could cause abrasion and wear of the bells and possibilities of further leakage.

While in the embodiment described above material is deposited by skip cars into the upper hopper l5 and passes through the chute to a selected port means, it is possible to deposit material in the upper hopper by other means.

FIG. 13 illustrates another embodiment of the invention in which material is deposited into upper hopper 15a by a known type of conveyor belt assembly 62, in which a belt 63 in housing 64 passes around end pulley 65 and deposits burden material in the hopper 15a which may be to one side of sleeve 25 of chute 24, the belt being driven and supplied by suitable known means, not shown. In an operation in which the belt brings burden material substantially continuously to hopper 15a, a material cutoff valve 66 is supplied at the bottom of hopper 15a to hold material in the hopper and prevent it from traveling through the chute at all times while the chute is not aligned with the mouth of a selected port means in which the gas sealing valve is open. Valve 66 has a closure member 67 that is shown as moved horizontally between open and closed positions by piston rod 68 of a fluid actuated cylinder 69 mounted on a frame member 70 of the blast furnace. The cylinder may be controlled to operate the valve at desired times by known means, not shown.

The remainder of the embodiment of FIG. 13 is the same as that of FIGS. l-6, and needs no further description as to structure, particularly since corresponding parts have identical reference characters in both embodiments.

A mode of operation of the embodiment of FIG. 13 will be apparent by reference to the discussion above in connection with FIGS. 7-12, when it is kept in mind that although charge material is substantially continuously discharged into hopper 15a, the material passes through chute 24 only when valve 66 is open and this corresponds to the time during operation of the embodiment of FIGS. l-12 when a skip car is discharging into the upper hopper.

For an alternative mode of operation in which the belt 63 brings up the burden material discontinuously in slugs so the burden material is intermittently supplied to hopper 15a so timed that no material is discharged from the belt while the valve means 39 aligned with the chute is closed, the valve 66 may be eliminated or left open, and the operation can then be substantially as described above in connection with the first embodiment utilizing skip car delivery of burden material.

FIG. 14 illustrates a system or introducing gases under pressure into the small bell hopper 5 and the large bell hopper 4 of any of the above embodiments, which system can be operated to provide the desired pres'surizing of the small bell hopper and of the large bell hopper as described above, and which can also be used to permit the apparatus-embodying the invention to be operated in a manner akin to a conventional twobell system in the event that any of the valve means 39 remains open as because of the need for repair, maintenance or other reasons.

The system of FIG. 14 is shown as applied to the embodiment of FIGS. 1-12, although it can be equally applied to the embodiment of FIG. 13' or other embodiments of the invention. In the apparatus of FIG. 14, indicated parts identical with those of the embodiment of FIGS. 1 to 12 bear the same reference characters for convenience in understanding.

In this embodiment, conduit 57 for supplying clean gas to the small bell hopper can communicate through its control valve 58 with clean gas supply main 72, which also can communicate through conduit 73 and its control valve 74 and with the interior of the large bell hopper 3. Conduit 59 for relieving pressure of clean gas in the small bell hopper can communicate through control valve 60 with a gas relief line 75, which line also can communicate through a conduit 76 and its control valve 77 with the interior of the large bell hopper 3, to make possible relief of gas pressure in the large bell hopper 3 when required.

Furthermore, another conduit78 is adapted to discharge gas into the interior of the large bell hopper through its control valve 79 from gas uptake 80 conventionally connected with the interior of the furnace outside of large bell hopper 3.

For the operations described above in connection with FIGS. 1 to 12 and FIG. 13,

valves

74 and 77 are at all times closed, and valve 79 between the uptake containing gas at furnace pressure and the interior of large hopper 3 is open at all times; and valves 58 and 6 0 are opened and closed as required to permit the introduction of clean gas into the small bell hopper and the relief of pressure in the small bell hopper as required by the operation.

However, if it should become necessary or desirable to operate the apparatus in a manner akin to conventional two bell systems because one or more of the valve means 39 is open at all times,

valves

58, 60 and 79 are closed and kept closed at all times, and

valves

74 and 77 are opened and closed as required to pressurize the interior of the large bell hopper with clean gas that approximates or is even slightly above furnace pressure and to relieve pressure in the large bell hopper, as required.

Under such circumstances an illustrative process of operating may be as follows, assuming that one or more of the valve means 39 is at all times open, the small bell is raised to close the bottom of small bell hopper 5, the large bell 4 is raised to close the bottom of large bell hopper 3, and the large bell hopper has been filled with clean gas through

conduits

72 and 73 and valve 74 to the desired pressure approximating furnace pressure,

and valve 74 is then closed. The chute 24 is aligned with a selected port means 36, and the desired amount of charge material is discharged through it into the closed small bell hopper by the skip car or conveyor supply means. The pressure in the large bell hopper is then relieved by opening valve 77 to line 75, and the small bell is thereafter dropped to discharge the charge material from the small bell hopper into the large bell hopper, after which the small bell is raised. This cycle of discharging material onto the small bell and then dropping it onto the large bell may be repeated one or more times as desired, with or without intermediate reprcssu'rizing and relieving of pressure in the large bell hopper. After the desired amount of material has been deposited on the large bell hopper, if desired in a distributed pattern around the large bell hopper by proper rotation of the chute to selected ones of the port means 36, the small bell is raised, the large bell hopper is pressurized with clean gas to a desired pressure of approximating that of the furnace pressure, and the large bell is then dropped to discharge material into the furnace, after which the large bell is raised, the large bell hopper is again repressurized with clean gas, andthe cycle is repeated. Of course, this cycle of operations can be modified as desired.

Various other modifications can be made in the apparatus discussed above.

For example, in any of the forms of apparatus discussed above, the alternative means illustrated in FIGS. l5, l6 and 17 can be employed at the lower end of the chute and the upper end of each mouth of each port means to shield against spillage of charge material out of the chute and over the edges of the port means, rather than the means described above in connection with FIGS. 2 and 3. i

In the apparatus illustrated in FIGS. 15 to 17 inclusive, the mouth 38 of the port means 36 are essentially similar to those previously described, except that they do not have any upstanding circular flange at the outer edge of the assembly of the merged mouths. Rather, there is a laterally extending flange 83 at least the outer edge of the mouths. The lower end of the chute 24 has fixed to it a laterally extending flange 84 that is closely adjacent to the upper surfaces of flange 83 and the mouths. This flange 84 as shown in FIG. 15 is generally sector-shaped, being wide enough to extend for some distance past the ridges 56 formed by

walls

54 and 55 of mouths of the port means, and long enough to extend over the flange 83 and cover essentially the entire length of the mouth under the flange as by extending to. inner upstanding flange 53. Consequently, when the chute is aligned with a port means, the entire upwardly open mouth is covered by the closely adjacent flange 84 and thus undesired escape of charge material is prevented. V

The present invention thus overcomes the disadvantages of prior apparatus, some of which have been dispressures and discharged into the atmosphere, are

greatly reduced because the volume of the small bell hopper used for pressure equalization by clean gas and discharge of gas into the atmosphere is much smaller than the valve of the large bell hopper that is used for these purposes in conventional practice.

Prevention of gas leakage is simplified because there is no rotating hopper or other part of large diameter that must be circumferentially sealed against gas leak age, and because each of the gas seal valves 39 is small and located away from heat and can be sealed by rubberlike or other sealing material. Moreover, when a gas seal valve 39 is closed, the pressure of gas below it tends to keep it closed. The gas seal valves are located in the illustrated embodiments so that they are not subjected to harmful heat that can cause deterioration.

Construction is simplified and less costly, especially in large furnaces. Little if any abrasion of bells occurs because there is little if any leakage of dust laden furnace gas between any bell and its seat when the bell is closed. lndeed, in operation as described above, there is no need for the large bell to be gas-tight, since pressures are the same on both sides of the bell so abrasion from gas leakage past the bell is eliminated. The large bell will therefor have a much longer life than in a conventional furnace, which is a very important advantage since maintenance costs are reduced and production losses for large bell maintenance or replacement are greatly reduced.

Furthermore, as indicated, the rotatable chute may be supported and driven entirely from outside of the apparatus and no part of the chute be in a hopper, so that problems of maintenance and repair are greatly minimized because of easy accessibility to the chute.

Moreover, in emergency, the gas seal valves can be repaired without taking the furnace off pressure, since the valves are easily accessible and quickly replaced, and since the furnace can be operated as indicated above with the valves open.

Various modifications apparent to those skilled in the art may be made in apparatus and methods indicated above, in addition to those indicated. It is intended that the patent shall cover by suitable expression in the appended claims whatever features of patentable novelty reside in the invention.

We claim:

1. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion having a generally vertical axis; a plurality of spaced port means surrounding said axis and mounted on said furnace portion, each of said port means having an upwardly open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas-sealing relation and for opening each of said port means independently of other port means; a chute mounted externally of said furnace portion and above said port means for rotation about said axis, said chute having an upper opening adapted to receive material deposited therein from a fixed location relative to the furnace, said chute having'a lower discharge opening adapted by rotation of said chute to be positioned over and in close proximity to the mouth of each port means of said plurality of port means so that material-will pass directly from said chute into said mouth of a selected port means of said plurality of port means and into said furnace when the valve means of said selected port means is opened, said chute providing a direct path for material received in said upper opening of said chute at said fixed location to pass to and through said lower material discharge opening of said chute while said chute is angularly positioned around said axis with its lower discharge opening over and in close proximity to the mouth of any selected port means of said plurality of port means when the valve means of said port means is opened regardless of which of said port means is said selected port means, said lower portion of said chute and each of said mouths of said port means including portions that cooperate to cause material to pass from said lower discharge opening of said chute into the mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entirelower portion is located externally of any enclosure adapted to contain said material; and means for depositing material into said upper opening of said chute from said fixed location relative to said furnace.

2. The apparatus of claim 1 in which the said upper furnace portion includes in said furnace portion a chamber having an interior into which charge material may pass through a port means when its valve means is opened, said chamber having a lower opening through which charge material may discharge from said chamber; and means for closing said chamber discharge opening in gas sealing relation.

3. The apparatus of claim 2 in which said upper furnace portion includes in said furnace portion a hopper below said chamber which hopper is adapted to receive charge material from said chamber, said hopper having a bottom opening; and bell means movable relatively to said bottom opening of said hopper to discharge material from said hopper.

4. The apparatus of claim -1 in which said means for depositing material into said upper opening of said chute comprises an upper hopper that is adapted to deposit material into said upper opening of said chute;

and means for depositing material into said upper hopdepositing material into said upper opening of said chute from a fixed location comprises-skip car means.

6. The apparatus of claim 1 in which said means for depositing material into said upper opening of said chute from a fixed location comprises conveyor means.

7. The apparatus of claim 1 in which said means for depositing material into said upper opening of said chute from a fixed location comprises a fixed hopper adapted to discharge material into said upper opening of said chute, conveyor means for depositing material into said hopper, and material cut-off means associated with said hopper to prevent discharge of material from said hopper until the lower opening of said chute is over the mouth of a selected port means and the valve means for said port means is opened.

8. The apparatus of claim 1 in which there are at least four of said port means.

9. The apparatus of claim 1 comprising shielding means around the mouth of said port means shaped so that material discharging from the lower opening of said chute will discharge into a mouth of a port means when its valve means is opened without discharging between adjacent mouths or alongside of said mouth.

10. The apparatus of claim 9 in which said shielding means is annular means.

11. The apparatus of claim 1 comprising material cutoff means to prevent discharge of material from said chute until the discharge opening of said chute is over the mouth of a selected port means and the valve means for said port means is open.

12. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion having a generally vertical axis; a plurality of spaced port means surrounding said axis and mounted on said furnace portion, each of said port means having an upwardly'open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas-sealing relation and for opening each of said port means independently of other port means; a chute mounted externally of said furnace portion and above said port means for rotation about said axis, saidchute having an upper portion adapted to receive material, said chute having a permanently open lower discharge opening adapted by rotation of said chute to be positioned over and in close proximity to the mouth of each port means of said plurality of port means so that material will pass directly from said chute into said mouth of a selected port means of said plurality of port means and into said furnace when the valve means of said selected port means is opened, said chute providing a direct path for material received in said upper portion of said chute to pass to and through said lower material discharge opening of said chute while said chute is angularly positioned around said axis with its lower discharge opening over and in close proximity to the mouth of any of said selected port means of said plurlaity of port means when the valve means of said port means is opened regardless of which of said port means is said selected port means, said lower portion of said chute and each of said mouths of said port means including portions that cooperate to cause material to pass from said lower discharge opening of said chute intothe mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entire lower portion is located externally of any enclosure adapted to containsaid material; and means for depositing material into said upper opening of said chute.

13. The apparatus of claim 12in which the said upper furnace portion includes in said furnace portion a chamber having an interior into which charge material may pass through a port means when its valve means is opened, said chamber having a lower opening through which charge material may discharge from said chamher; and means for closing said chamber discharge opening in gas sealing relation.

14. The apparatus of claim 13 in which said upper furnace portion includes in said furnace portion a hopper below said chamber which hopper is adapted to receive charge material from said chamber, said hopper having a bottom opening; and bell means adapted to be raised and lowered with respect to said bottom opening of said hopper.

15. The apparatus of claim 12 comprising shielding means around the mouth of said port means shaped so that material discharging from the lower opening of said chute will discharge into a mouth of a port means when its valve means is opened without discharging between adjacent mouths or alongside of said mouth.

16. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion having a generally vertical axis; a plurality of spaced port means surrounding said axis and mounted on said furnace portion, each of said port means having an upwardly open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas-sealing relation and for opening each of said port means independently of other port means; a chute mounted externally of said furnace portion and above said port means for rotation about said axis, said chute having an upper opening surrounding said furnace axis and adapted to receive material deposited therein from a fixed location relative to the furnace, said chute having a single lower discharge opening adapted by rotation of said chute to be positioned over and in close proximity to the mouth of each port means of said plurality of port means so that material will pass directly from said chute into said mouth of a selected port means of said plurality of port means and into said furnace when the valve means of said selected port means is opened, said chute providing a direct path for material received in said upper opening of said chute at said fixed location to pass to and through saidlower material discharge opening of said chute while said chute is angularly positioned around said axis with its lower discharge opening over and in close proximity to the mouth of any of said port means of said plurality of port means when the valve means of said port means is opened regardless of which of said port means is said selected port means, said lower portion of said chute and each of said mouths of said port means including portions that cooperate to cause material to pass from said lower discharge opening of said chute into the mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entire lower portion is located externally of any enclosure adapted to contain'said material; and means for depositing material into said upper opening of said chute'from said fixed location relative to said furnace.

17. The apparatus of claim 16 in which the said upper furnace portion includes in said furnace portion a chamber having an interior into which charge material may pass through a port means when its valve means is opened, said chamber having a lower openingthrough which charge material may discharge from said chamber; and means for closing said chamber discharge opening in gas sealing relation.

18. The apparatus of claim 17 in which said upper furnace portion includes in said furnace portion a hopper below said chamber which hopper is adapted to receive charge material from said chamber, said hopper having a bottom opening; and bell means adapted to be raised and lowered with respect to said bottom opening of said hopper.

19. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion; a plurality of port means mounted on and laterally spaced on said furnace portion, each of said port means having an upwardly open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas sealing relation and for opening each of said port means independently of other port means; a chute movably mounted externally above said furnace portion and above said port means and having an upper receiving portion adapted to receive material from a fixed location relative to said furnace and a lower discharge portion adapted by lateral movement of said chute to be moved over said mouths of each of said plu rality of port means, said chute being adapted to receive material in its upper receiving portion fromsaid fixed location and to pass said material directly through said-lower chute portion to the mouth of a selected port means of said plurality of said port means and into said furnace when the valve means of said port means is opened regardless of which of said port means of said plurality of port means is said selected port means, said lower portion of said chute and each of said mouths of said port means including portions that cooperate to cause material to pass from said discharge opening of said chute into the mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entire lower portion is located externally of any enclosure adapted to contain said material; and means for depositing material into said upper portion of said chute from said fixed location relative to the furnace.

20. The apparatus of claim 19 in which the said upper furnace portion includes in said furnace portion a chamber having an interior-into which charge material may pass through a port means when its valve means is opened, said chamber having a lower opening through which charge material may discharge from said chamber; and means for closing said chamber discharge opening in gas sealing relation.

21. The apparatus of claim 20 in which said upper furnace portion includes in said furnace portion a hopper below said chamber which hopper is adapted to receive charge material from said chamber, said hopper having a bottom opening; and bell means movable relatively to said bottom opening of said hopper to discharge material from said hopper.

22. The apparatus of claim 19 in which said means for depositing material into said upper opening of said chute from a fixed location comprises skip car means.

23. The apparatus of claim 19 in which said means for depositing material into said upper opening of said chute from a fixed location comprises conveyor means.

24. The apparatus of claim 19 in which said means for depositing material intosaid upper opening of said chute from a fixed location comprises a fixed hopper adapted to discharge material into said upper opening of said chute, conveyor means for depositing material into'said hopper, and material cut-off means associated with said hopper to prevent discharge of material from said hopper until the lower portion of said chute is over the mouth of a selected port means and the valve means for said port means is opened.

25. The apparatus of claim 19 comprising material cutoff means to prevent discharge of material from said chute until the discharge opening of said chute is over the mouth of a selected port means and the valve means for said port means is opened.

26. The apparatus of claim 19 in which there are at least four of said port means.

27. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion; a plusealing relation and for opening each of said port means independently of other port means; a chute movably mounted externally above said furnace portion and above said port means and having an upper portion adapted to receive material and a lower portion with a permanently open lower discharge, opening adapted by lateral 'movement of said chute to be moved over said mouths of said plurality of port means and to be positioned over and in close proximity to the mouth of a selected port means of said plurality of port means to permit material to pass from said chute through said rality of port means mounted on and laterally spaced on said furnace portion, each of said port means having an upwardly open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas discharge opening directly into the mouth of said open port means and into said furnace when the valve means of said port means is opened, said lower portion of said chute and each of said said mouths of said port means including portions that cooperate to cause material to pass from said discharge opening of said chute into the mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entire lower portion is located externally of any enclosure adapted to contain said material; and means for depositing material into said upper portion of said chute. g I

28.- The apparatus of claim 27 in which the said upper furnace portion includes in said furnace portion a chamber having an interior into which charge material may pass through a port means when its valve means is opened, said chamber having a lower opening through which charge material may discharge from said chamber; and means for closing said chamber discharge opening in gas sealing relation.

29. The apparatus of claim 28 in which said upper furnace portion includes in said furnace portion a hopper below said chamber which hopper is adapted to receive charge material from said chamber, said hopper having a bottom opening; and bell means movable relatively to said bottom opening of said hopper to discharge material from said hopper.

30. The apparatus of claim 27 in which said means for depositing material into said upper opening of said chute from a fixed location comprises skip car means.

31. The apparatus of claim 27 in which said means for depositing material into said upper opening of said chute from a fixed location comprises conveyor means.

32. The apparatus of claim 27 comprising shielding 'means'around the mouth of said port means shaped so that material discharging from the lower opening of said chute will discharge into a mouth of a port means when its valve means is opened without discharging between adjacent mouths or alongside of said mouth.

Claims

1. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion having a generally vertical axis; a plurality of spaced port means surrounding said axis and mounted on said furnace portion, each of said port means having an upwardly open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas-sealing relation and for opening each of said port means independently of other port means; a chute mounted externally of said furnace portion and above said port means for rotation about said axis, said chute having an upper opening adapted to receive material deposited therein from a fixed location relative to the furnace, said chute having a lower discharge opening adapted by rotation of said chute to be positioned over and in close proximity to the mouth of each port means of said plurality of port means so that material will pass directly from said chute into said mouth of a selected port means of said plurality of port means and into said furnace when the valve means of said selected port means is opened, said chute providing a direct path for material received in said upper opening of said chute at said fixed location to pass to and through said lower material discharge opening of said chute while said chute is angularly positioned around said axis with its lower discharge opening over and in close proximity to the mouth of any selected port means of said plurality of port means when the valve means of said port means is opened regardless of which of said port means is said selected port means, said lower portion of said chute and each of said mouths of said port means including portions that cooperate to cause material to pass from said lower discharge opening of said chute into the mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entire lower portion is located externally of any enclosure adapted to contain said material; and means for depositing material into said upper opening of said chute from said fixed location relative to said furnace.

4. The apparatus of claim 1 in which said means for depositing material into said upper opening of said chute comprises an upper hopper that is adapted to deposit material into said upper opening of said chute; and means for depositing material into said upper hopper.

5. The apparatus of claim 1 in which said means for depositing material into said upper opening of said chute from a fixed location comprises skip car means.

10. The apparatus of claim 9 in which said shielding means is annular means.

12. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion having a generally vertical axis; a plurality of spaced port means surrounding said axis and mounted on said furnace portion, each of said port means having an upwardly open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas-sealing relation and for opening each of said port means independently of other port means; a chute mounted externally of said furnace portion and above said port means for rotation about said axis, said chute having an upper portion adapted to receive material, said chute having a permanently open lower discharge opening adapted by rotation of said chute to be positioned over and in close proximity to the mouth of each port means of said plurality of port means so that material will pass directly from said chute into said mouth of a selected port means of said plurality of port means and into said furnace when the valve means of said selected port means is opened, said chute providing a direct path for material received in said upper portion of said chute to pass to and through said lower material discharge opening of said chute while said chute is angularly positioned around said axis with its lower discharge opening over and in close proximity to the mouth of any of said selected port means of said plurlaity of port means when the valve means of said port means is opened regardless of which of said port means is said selected port means, said lower portion of said chute and each of said mouths of said port means including portions that cooperate to cause material to pass from said lower discharge opening of said chute into the mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entire lower portion is located externally of any enclosure adapted to contain said mAterial; and means for depositing material into said upper opening of said chute.

13. The apparatus of claim 12 in which the said upper furnace portion includes in said furnace portion a chamber having an interior into which charge material may pass through a port means when its valve means is opened, said chamber having a lower opening through which charge material may discharge from said chamber; and means for closing said chamber discharge opening in gas sealing relation.

16. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion having a generally vertical axis; a plurality of spaced port means surrounding said axis and mounted on said furnace portion, each of said port means having an upwardly open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas-sealing relation and for opening each of said port means independently of other port means; a chute mounted externally of said furnace portion and above said port means for rotation about said axis, said chute having an upper opening surrounding said furnace axis and adapted to receive material deposited therein from a fixed location relative to the furnace, said chute having a single lower discharge opening adapted by rotation of said chute to be positioned over and in close proximity to the mouth of each port means of said plurality of port means so that material will pass directly from said chute into said mouth of a selected port means of said plurality of port means and into said furnace when the valve means of said selected port means is opened, said chute providing a direct path for material received in said upper opening of said chute at said fixed location to pass to and through said lower material discharge opening of said chute while said chute is angularly positioned around said axis with its lower discharge opening over and in close proximity to the mouth of any of said port means of said plurality of port means when the valve means of said port means is opened regardless of which of said port means is said selected port means, said lower portion of said chute and each of said mouths of said port means including portions that cooperate to cause material to pass from said lower discharge opening of said chute into the mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entire lower portion is located externally of any enclosure adapted to contain said material; and means for depositing material into said upper opening of said chute from said fixed location relative to said furnace.

17. The apparatus of claim 16 in which the said upper furnace portion includes in said furnace portion a chamber having an interior into which charge material may pass through a port means when its valve means is opened, said chamber having a lower opening through which charge material may discharge from said chamber; and means for closing said chamber discharge opening in gas sealing relation.

19. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion; a plurality of port means mounted on and laterally spaced on said furnace portion, each of said port means having an upwardly open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas sealing relation and for opening each of said port means independently of other port means; a chute movably mounted externally above said furnace portion and above said port means and having an upper receiving portion adapted to receive material from a fixed location relative to said furnace and a lower discharge portion adapted by lateral movement of said chute to be moved over said mouths of each of said plurality of port means, said chute being adapted to receive material in its upper receiving portion from said fixed location and to pass said material directly through said lower chute portion to the mouth of a selected port means of said plurality of said port means and into said furnace when the valve means of said port means is opened regardless of which of said port means of said plurality of port means is said selected port means, said lower portion of said chute and each of said mouths of said port means including portions that cooperate to cause material to pass from said discharge opening of said chute into the mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entire lower portion is located externally of any enclosure adapted to contain said material; and means for depositing material into said upper portion of said chute from said fixed location relative to the furnace.

20. The apparatus of claim 19 in which the said upper furnace portion includes in said furnace portion a chamber having an interior into which charge material may pass through a port means when its valve means is opened, said chamber having a lower opening through which charge material may discharge from said chamber; and means for closing said chamber discharge opening in gas sealing relation.

24. The apparatus of claim 19 in which said means for depositing material into said upper opening of said chute from a fixed location comprises a fixed hopper adapted to discharge material into said upper opening of said chute, conveyor means for depositing material into said hopper, and material cut-off means associated with said hopper to prevent discharge of material from said hopper until the lower portion of said chute is over the mouth of a selected port means and the valve means for said port means is opened.

27. Apparatus for charging material into a shaft furnace comprising a closed upper furnace portion; a plurality of port means mounted on and laterally spaced on said furnace portion, each of said port means having an upwardly Open mouth and communicating between the exterior and the interior of said furnace portion; valve means for closing each of said port means in gas sealing relation and for opening each of said port means independently of other port means; a chute movably mounted externally above said furnace portion and above said port means and having an upper portion adapted to receive material and a lower portion with a permanently open lower discharge opening adapted by lateral movement of said chute to be moved over said mouths of said plurality of port means and to be positioned over and in close proximity to the mouth of a selected port means of said plurality of port means to permit material to pass from said chute through said discharge opening directly into the mouth of said open port means and into said furnace when the valve means of said port means is opened, said lower portion of said chute and each of said said mouths of said port means including portions that cooperate to cause material to pass from said discharge opening of said chute into the mouth of a selected port means when its valve means is opened without spillage of material outside of said mouth; means for supporting and moving said chute so essentially its entire lower portion is located externally of any enclosure adapted to contain said material; and means for depositing material into said upper portion of said chute.

28. The apparatus of claim 27 in which the said upper furnace portion includes in said furnace portion a chamber having an interior into which charge material may pass through a port means when its valve means is opened, said chamber having a lower opening through which charge material may discharge from said chamber; and means for closing said chamber discharge opening in gas sealing relation.

32. The apparatus of claim 27 comprising shielding means around the mouth of said port means shaped so that material discharging from the lower opening of said chute will discharge into a mouth of a port means when its valve means is opened without discharging between adjacent mouths or alongside of said mouth.