US2965249A - Charging devices for shaft furnaces - Google Patents

Description

1960 l. E. JOHANSSON ,96

CHARGING DEVICES FOR SHAFT FURNACES Filed Dec. 16, 1957 4 Sheets-Sheet 1 2 22 26 Fig 1 35 35 55 i 25 21 E 20 WE ;1- 7 7 s9 18 19 I B I INVENTOR ISAK EDVIN JOHANSSON BUCKHORN,CHEATHAM 8 BLORE A TTOIPNEVS 20, 1960 I. E. JOHANSSON 2,965,249

CHARGING DEVICES FOR SHAFT FURNACES Filed Dec. 16, 1957 4 Sheets-Sheet 2 2o Fig.2 23 34 34 51 2 a. 23 l i H 5U 50 J 50 h LB 27 INVENTO/P ISAK EDVIN JOHANSSQN BUCKHORN,CHEATHAM 8BLORE ATTORNEYS I. E. JOHANSSON 4 Sheets-Sheet 5 Fig. A

INVENTO/i ISAK EDVIN JOHANSSON BUCKHORN,CHEATHAM 8.BLORE ATTORNEYS Dec. 20, 1960 I CHARGING DEVICES FOR SHAFT FURNACES Filed Dec. 16, 1957 1366- 1960 l. E. JOHANSSON CHARGING DEVICES FOR SHAFT FURNACES 4 Sheets-Sheet 4 Filed Dec. 16, 1957 INVENTO/P ISAK EDVI N JOHANSSON BUCKHORN, CHEATHAM & BLORE A TTORNEYS the upper bell.

United States PatentO CHARGING DEVICES FOR SHAFT FURNACES Isak 'Edvin Johansson, Stockholm, Sweden, assignor to T. An. Tesch Aktiebolag, Stockholm, Sweden, a corporation of Sweden Filed Dec. 16, 1957, Ser. No. 703,202

Claims priority, application Sweden Oct. 15, 1957 .8 Claims. (Cl. 214-36) The present invention relates to shaft furnaces equipped with a charging device comprising two hoppers, the upper hopper being rotatable. By'the rotatable arrangementof the upper hopper, the stock supplied thereto (usually from one side thereof) will be distributed-uniformly around the circumference of the hopper before it is fed to the furnace.

In charging devices of the known type it is necessary to provide sealing means to prevent leakage of gas between the stationary part of thefurnace and the rotatable upper hopper.

For this purpose sealing devices of various types have been used, e.g. devices similar to stuffing boxes such as used-for rotating shafts. Metal rings have also been used.

On account of the great diameter of the sealing'surfacc (usually around 2 meters) it has proved difficult to achieve a satisfactory sealing effect by means of such sealing devices. Furthermore, the known sealing devices cause a rather great frictional resistance and are worn out relatively quickly.

'It has also been suggested to use water or oil seals to provide sealing. These have the disadvantage that they are blown out in the event of a high pressure in the furnace and also the disadvantage that the liquid is vaporized since the walls of the liquid seal is heated from the shaft furnace. In furnaces operating with a high gas pressure liquid seals cannot be provided on account of lack of space.

The main object of the present invention is to provide sealing means for charging devices of the type referred to, which sealing means are free from the disadvantages of the prior art sealing devices. Other objects and advantages will appear as the description proceeds.

According to the present invention, there is arranged below the bottom closing-bell of the rotatable upper hopper, said bell being rotatable together with the hopper, a second non-rotatable bell, which may partly be enclosed in the rotatable bell. Todump the stock from the upper hopper to the lower hopper of the charging device, both bells may be lowered together or independently. Each bell is suspended on a tubular central rod, the rod associated with the lower bell being enclosed by the rod of The upper feed opening of the lower hopper of the charging device has a diameter larger than the diameter of the upper rotatable hell, but less than that of the lower, non-rotatable bell. To empty the upper hopper, the upper rotating bell may pass through the feed opening of the lower hopper and then return to close the bottom of the upper hopper.

The lower, non-rotatable bell is lowered, when the stock is to be .dumped, into the lower hopper of the charging device and thereafter returns to its upper position, in which it engages sealingly the lower edge of the feed opening of the lower hopper.

.In one embodiment of the invention, in which the bells are moved vertically together, it is of importance that the Ill F 2,9652% Ce Patented Dec. 20, 1960 feed opening-of the lower'hopper before the upper rotating bell engagesthe lower edge of the .upper hopper. For this purposethere is a small clearance between the upper bell and the upper hopper, and to adjust the width of the clearance the vertical spacing of the bells may be adjusted by inserting or removing washers at the pointwhere the rod of the lower bell is supported.

To prevent oscillation and oblique positioning of the upper rotatable bell in its upper position, a number of at the platforms'of the furnace, a chamber may beprovided around the lower portion of the upper hopper, adapted'to collect the gas'flowing out and pass it into the rotating'hopper or pass it away through an exhaust pipe from the chamber.

Two embodiments of ,theinvention are shown on the accompanying drawing.

Figure 1 shows, partly in vertical section, a shaft furnace-with a charging device'the upper hopper of which is constructed in accordance with this invention.

Figure 2 shows the upper hopper on a larger scale and in vertical section.

Figure 3 shows parallel guidance means for the bell rods in elevation.

Figure -4-shows in vertical section the mounting of the bell rods in an embodiment with simultaneous vertical and 2, the character A denotes a shaft furnace having a charging device comprising a lower hopper B and an upper hopper C. The stock to be charged is supplied to the upper'hopper C by the skip car 1. When the upper hopper C is filled with stock, it is turned through a certain angle, different for different loads in accordance with a predetermined program.

The upper hopper C comprises an upper cylindrical part 2,'a lower conical part 3 and a bottom bell 4. These parts form-the'rotating assembly, the rotating movement of the parts 2 and 3 being imparted to the hell 4 by the intermediary of the stock introduced into the hopper C. The rotating movement is imparted to the hopper C by a driving unit anchored to the stationary part of the furnace and comprising an electric motor 6, an encased worm-gear 7 and a gear-wheel 8. The gear-wheel drives the hopper C by means of the toothed gear 9 which is afiixed to the lowcr'part 3 of the hopper C. Thehopper C is supported vertically and guided horizontally by a number of roller units secured to the stationary part of thefurnace, each roller unit comprising a supporting roller 10 with a shaft 11, a guiding roller 12 and a mounting 13. A replaceable tread '14 for the rollers 10 is afiixed to a flange of the part 3.

The lower hopper'B comprises a frustoconical annulus 15 which supports the driving unit and the supporting and guiding units of the hopper C and forms a circular lower opening for feed of the stock from the hopper C, an upper frustoconical part 16 and a lower funnel-shaped part 17. At itstop the hopper B is closed sealingly by the bell 5 when this is in its upper position, as shown in Figure 2. At its bottom the hopper B is closed in a wellknownmanner by a bell 18 below which there is arranged a stock distributing bell 19.

Charging of the stock takes placein the following manher. When the hopper C has been filled with stock and the hopper has been turned a desired angle in accordance with a predetermined program, the bells and 4 are lowered independently or together to the positions indicated by 5' and 4', whereupon the stock will be dumped from the hopper C into the hopper B. Thereupon, the bells 5 and 4 are returned to their upper positions. When the hopper B (which accommodates more than one load from the hopper C) is filled with stock to a suitable level, it is emptied (after the bells 4 and 5 have returned to their upper positions) by raising the bottom bell 18 of the hopper B. Prior to this operation, the distributing bell 19 has been adjusted to a suitable level for the desired distribution of the stock in the furnace. When the hopper B is emptied, the bells 18 and 19 return to their closing positions. The bell 19 is carried by a central rod 20, a cable 21 and a sheave 22. The bell 18 is carried by a tubular rod 23 (within which the rod is disposed) cross pieces 24, cables 25 and sheaves 26. The bell 5 is carried by a tubular rod 27 (within which the rods 20 and 23 are disposed), and the bell 4 is carried by a tubular rod 28 (within which the rods 20, 23 and 27 are disposed). At the top end of the rod 28, there is secured a sleeve 29, to which is affixed a nut 30 which is supported by an axial ball bearing 31. The ball bearing 31 is supported on a washer 32, which is bolted to a support 33. This support 33 is carried by two cables 34 and sheaves 35.

Figure 4 which illustrates the embodiment in which the bells and 5 are moved together vertically, and Figure 5 which illustrates an embodiment in which the vertical movements of the bells take place independently, difier in construction as regards the mounting of the rod 27. According to Figure 4 a sleeve 36 is secured to the top end of rod 27, said sleeve resting on the support 33 by the intermediary of washers 37. It will be understood that lifting of the bells 4 and 5 takes place simultaneously by means of the support 33 and that the rod 28 with the bell 4 can turn on the ball bearing 31 without entraining the rod 27 with the bell 5 in the turning movement. In order that the hell 5 shall not be prevented from engaging sealingly the annular part 15, the vertical spacing between the bells 4 and 5 is selected so that a clearance 38 is provided between the bell 4 and the lower hopper part 3.'

The width of the clearance is adjusted by inserting or removing washers 37.

In Figure 5, the rod 27 is not carried by the support 33, but by a separate support 39, which is secured to the rod 27. The support 39 is carried by cables 40 and two sheaves (not shown in the drawing). It will be understood that the bells 4 and 5 are lifted and lowered independently and that the rod 28 with the hell 4 may rotate on the ball bearing 31 without entraining the rod 27 with the bell 5 in its rotation.

Stuffing- boxes 41, 42 and 43 are provided to efiect sealing between the rods against leakage of gas. A ring 44 is provided to seal the ball bearing housing. 45 is a sleeve protecting the rod 28 against abrasion.

To guide the bell 4 to a horizontal central position in its highest position, reenforcing ribs on the lower wall 3 extend downwardly below the lower edge of the hopper C to serve as guides 45a for the bell 4.

Figure 3 illustrates a suitable arrangement for horizontal positioning and vertical guidance of the bell rods. On each end of the support 33 there is attached a pivotable link 46. The two links 46 are united by beams 47 and 48. At their ends, the links 46 have pivots 49 to which are attached rods 50 and 51. The rods are at their opposite ends attached to the stationary structure 54 of the furnace by means of pivots 52 and brackets 53. The rods 50 and 51 are so inclined relatively to each other that when the support 33 with its associated parts is lowered or lifted, its movement will be vertical. In Figure 3, therods 50 and 51 are shown in full lines in their positions corresponding to the upper position of the support 33 and in dash-and-dot lines 50' and 51' in their positions corresponding to the lower position of the support 33. Stationary structure for supporting the shaft of the sheaves 22, 26 and 35 is indicated at 55 (Figure 1).

In the lower left-hand portion of Figure 2, a modification is illustrated, in which a closed space D is provided, which is maintained relatively gas-tight toward the ambient atmosphere by the provision of an upper ring 56 and a lower ring 57 of triangular cross-section. The lower ring 57 may be divided radially in a plurality of segments arranged with clearances between their opposed ends, so that even if wear occurs this ring may be kept in engagement with the rotatable lower wall 3 by the pressure of the ring 56. By the provision of the space D gas escaping from the hopper B will be forced to flow either through the clearance 38 into the hopper C or away through a pipe 58 (shown in dot-and-dash lines). The numeral 59 designates the gas offtake from the furnace.

It will be obvious to those skilled in the art that the construction and arrangement of the charging device can be modified without departing from the spirit and scope of this invention. Thus, the vertical movements of the bell rods may be achieved via levers by means of pneumatic or hydraulic rams arranged directly on the bell rods, by electrical hoisting devices arranged to act directly on the rods, or other means. Furthermore, the means for sealing the space D can be varied. Other variations and modifications will be obvious to those skilled in the art.

I claim:

1. A charging device for shaft furnaces, comprising a lower stationary hopper, an upper rotatable hopper, an upper rotatable bell adapted to partake in the rotation of the upper rotatable hopper and adapted to be moved vertically between an upper position in which it closes the bottom opening of the upper bell and a lower position in which it opens said opening to permit dumping of stock from the upper hopper to the lower hopper, and a lower non-rotatable bell which is disposed below the upper feed opening of the lower hopper and has a greater diameter than said feed opening, said lower bell being adapted to be vertically moved between an upper position in which it engages sealingly the edge of the feed opening of the lower hopper to prevent leakage of gas therefrom and a lower position in which it opens the feed opening to permit dumping a stock into the lower hopper, said upper rotatable bell having a smaller diameter than the feed opening of the lower hopper so that it can pass there- A through.

2. The device as in claim 1, in which rods are provided to effect vertical movement of the bells, the rod for the lower bell being enclosed in the rod for the upper bell, said rods being adapted to be moved simultaneously, and in which removable washers are arranged at the seating of the rod of the lower bell to vary the spacing between the upper bell and the lower bell.

3. A device as in claim 1, in which guiding ribs to guide the rotatable bell to a central position in its upper position are provided at the lower edge of the rotatable hopper.

4. A device as in claim 1 in which a space is provided around the lower portion of the rotatable hopper to collect gas escaping from the lower hopper when the lower bell is lowered, said gas being passed to the interior of the rotating hopper.

5. A device as in claim 4 in which a gas outlet conduit is provided to withdraw gas from said space.

6. A charging device for a shaft furnace comprising a rotatable hopper having a bottom opening, an upper rotatable bell adapted to partake in the rotation of the rotatable hopper and movable vertically between an upper position in which it closes said bottom opening of said rotatable hopper and a lower position in which it opens said opening to permit dumping of stock from said rotat- @9 6 QPP through said bottom opening, a tubular lifting rod attached to said upper bell to effect such movements of said upper bell, stationary means below said rotatable hopper defining a feed opening in alignment with said bottom opening of said rotatable hopper, said feed opening being of a diameter greater than that of said upper bell, a lower non-rotatable bell disposed below said means and having a greater diameter than said feed opening and movable vertically between an upper position in which it engages sealingly the edge of said feed opening to prevent leakage of gas therethrough and a lower position in which it opens said feed opening to permit dumping of stock therethrough, a lifting rod extending within said tubular lifting rod and attached to said lower bell to effect such movements of said lower bell, and guiding ribs attached to said rotatable hopper around said bottom opening thereof to guide said rotatable bell to a central position in its upper position.

7. A charging device for a shaft furnace comprising a rotatable hopper having a bottom opening, an upper rotatable bell adapted to partake in the rotation of the rotatable hopper and movable vertically between an upper position in which it closes said bottom opening of said rotatable hopper, but leaves narrow annular clearance around the circumference of said bottom opening, and a lower position in which it opens said opening to permit dumping of stock from said rotatable hopper through said bottom opening, a tubular lifting rod attached to said upper bell to effect such movements of said upper bell, stationary means below said rotatable hopper defining a feed opening in alignment with said bottom opening of said rotatable hopper, said feed opening being of a diameter greater than that of said upper bell, a lower non-rotatable bell disposed below said means and having a greater diameter than said feed opening and movable vertically between an upper position in which it engages sealingly the edge of said feed opening to prevent leakage of gas therethrough and a lower position in which it opens said feed opening to permit dumping of stock therethrough, a lifting rod extending within said tubular lifting rod and attached to said lower bell to effect such movements of said lower bell, and means associated with said tubular lifting rod and said lifting rod to move said upper and lower bells simultaneously between their upper and lower positions.

8. A charging device for a shaft furnace comprising a rotatable hopper having a bottom opening, an upper rotatable bell adapted to partake in the rotation of the rotatable hopper and movable vertically between an upper position in which it closes said bottom opening of said rotatable hopper, but leaves a narrow annular clearance around the circumference of said bottom opening, and a lower position in which it opens said opening to permit dumping of stock from said rotatable hopper through said bottom opening, a tubular lifting rod attached to said upper bell to effect such movements of said upper bell, stationary means below said rotatable hopper defining a feed opening in alignment with said bottom opening of said rotatable hopper, said feed opening being of a diameter greater than that of said upper bell, a lower nonrotatable bell disposed below said means and having a greater diameter than said feed opening and movable vertically between an upper position in which it engages sealingly the edge of said feed opening to prevent leakage of gas therethrough and a lower position in which it opens said feed opening to permit dumping of stock therethrough, a lifting rod extending within said tubular lifting rod and attached to said lower bell to effect such movements of said lower bell, a stationary hopper below said stationary means for receiving stock dumped from said rotatable hopper and having a bottom opening, a second nonrotatable bell adapted to close said bottom opening of said stationary hopper and to open said bottom opening to permit dumping of stock from said stationary hopper, and cooperating sealing means carried by said rotatable hopper and said stationary means for providing a sealed gas-collecting space around the lower end of said rotatable hopper and in communication with said narrow clearance.

References Cited in the file of this patent UNITED STATES PATENTS 1,178,522 Kennedy Apr. 11, 1916 2,560,844 Brun et al July 17, 1951 2,667,278 Tesch et al. Jan. 26, 1954 2,674,382 Tesch Apr. 4, 1954

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