US2674382A

US2674382A - Shaft furnace charging device

Info

Publication number: US2674382A
Application number: US164012A
Authority: US
Inventors: Tesch Erik Torsten Anderson; Johansson Isak Edvin
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-06-01
Filing date: 1950-05-24
Publication date: 1954-04-06
Anticipated expiration: 1971-04-06

Description

Ap 6, 1954 E. T. A. TESCH ETAL SHAFT FURNACE CHARGING DEVICE 3 Sheets-Sheet 1 Filed May 24, 1950 INVENTORS Erik Torsten Anderson Tesch 8 Isak Edwin Johonsson ATTORNEYS Apr 6, 1954 E. 1-. A. TESCH ETAL SHAFT FURNACE CHARGING DEVICE 3 Sheets-Sheet 2 Filed May 24, 1950 INVENTORS Erik Torsten Andefson Tesch 8: Isak Edvin Johmnsson ATTORNE S v BY April 6, 1954 E. T. A. TESCH ETAL SHAFT FURNACE CHARGING DEVICE 3 Sheets$heet 3 Filed May 24, 1950 INVENTORS son Tesch Erik Torsien Ander ATTORNEYS Patented Apr. 6, 1954 SHAFT FURNACE CHARGING DEVICE Erik Torsten Anderson 'ilesch, Stockholm, and Isak Edvin Johansson, Alvsjo, Sweden Application May 24, 1950, Serial No. 164,012

Claims priority, application Sweden June 1, 1949 2 Claims.

pass through a cone when falling into the shaft furnace, which is now usually practiced, does not result in the desired distribution, inter owing to the tendency of the material to separate according to size and specific gravity. The rising gases follow the law of least resistance and thus they flow more amply where coarser material is concentrated and the charge is looser than where there is finer material and the charge is correspondingly tighter. This will cause uneven reduction of the ore in the material and the useful volume of the furnace will be less effectively utilized. Moreover, the departing gas will be too ununiformly composed causing a reduction of heat economy. Disturbances in operation may also result on account of the gas forming irregu- 1 lar passages in the material.

One way of obtaining a more uniform gas flow in the furnace is to charge a comparatively large quantity of small size material concentrically around the wall of the furnace, so called charge on the wall, and a comparatively smaller quantity of coarser material in the central part of the furnace, so called charge in the centre.

A disadvantage with such charging tops, however, is that charging requires expensive manual labour for loading and separating the smallpiece material and further they can not be designed for double closure, which allows the gas to escape through the top, while the material is being introduced into the furnace.

In order to obtain a better distribution of the material it has also been suggested to close the opening of the cone-shaped bottom of the charging top by means of a conical valve which,

in order to empty the charging top, may either be raised above its closing position, when the material is to fall into the centre of the furnace, or be lowered below said position, when the ma terial is to fall outwardly towards the furnace wall.

Also this device, however, has disadvantages in as much as the height of fall of the material is changed, when the conical valve is moved from a position above the opening in the bottom To prevent such a change in the height of fall of the material in operating the conical valve, the bottom closure of the charging top according to the present invention comprises two conical valve members arranged one below the other and each being adapted to be raised and lowered, at least the lower one of said valve members being smaller than the opening in the bottom of the charging top, so that said lower valve not only can be raised above said opening together with the upper one in order to effect a central charge but also independently of the upper valve can be lowered below the opening in order to allow charge on the wall.

When material is to be fed to the centre of the shaft furnace both valves are raised together, whereas when the material is to be fed around the wall of the furnace, the lower valve is first lowered to its lowermost position, whereupon the upper valve is raised to its uppermost position. Thus the material during the whole charge will fall from a constant height against the lower valve and will slide along the conical surface of the latter out towards the wall of the shaft furnace. Preferably the upper valve is so shaped that it is somewhat larger than the opening in the bottom of the charging top, thus ensuring a gas-tight seal when the valve is in its lowered position.

In order to further ensure feeding of the material towards the wall the upper part of the furnace, according to one embodiment of the invention, may be provided with a fixed conical guide-casing having a central passageway, the lower conical valve cooperating with said casing when lowered to a position below the opening in the bottom of the charging top, said casing also being arranged so as to allow the material to fall through the central passageway of the casing when the lower valve is in its raised position.

This device ensures a very favourable distributicn of the material in the furnace.

According to another embodiment of the invention the conical guide-casing and maybe also the lower conical valve is provided with a number of radial ridges or grooves which ensure a radial and circumierentially equal flow of material towards the wall of the furnace.

Experience has proved that material sliding down along a smooth cone does not always move radially outwards. Often, especially when handling material comprising pieces of different sizes, this sliding motion will be irregular and in of the charging top to a position below the same. 55

places may diverge in tangential direction so that the material will not be passed down evenly distributed as desired.

By providing the distributor with radial guide ridges the material is prevented from diverging in tangential direction, but is guided in grooves radially outwards so that the charge will be en tirely uniform around the circumference of the furnace where the risk of an uncontrolled passage of gas is the greatest.

Further, the conical casing according to the invention may be extended downwards from its outer periphery with a cylindrical or nearly cylindrical part adapted to guide the material of the charge concentrically along the furnace wall.

Other features of the invention willbe further indicated in the following description referring to the shaft furnace illustrated in the accompanying drawings, in which:

Fig. 1 is a vertical section through the furnace and charging top, while Fig. 2 illustrates a part thereof. Figs. 3 and 4 show the charging top and adjacent parts of the furnace on a somewhat larger scale and in two different positions of operation.

The shaft furnace is designated A, the lower container of the double charging top is designated B and its upper container C. The latter is preferably rotatably mounted on rollers 2. The material is supplied to the furnace by the selftilting wagon l. After a suflicient quantity of material has been supplied to the container ,0, the conical valve 3 is lowered by means of the compressed air cylinder 4, the lever 5 with its counter-weight 6 and the hollow supporting rod 1. The charge material will thus slide down from the container C to the container B, whereupon the container C is closed by the valve 3 again being raised against the conically shaped bottom 8 of the container.

After this the material is expelled from the container B intothe shaft furnace A either by raising *both

conical valves

9 and 25 according to Fig. 3, thus allowing the material to fall down into the centre of the furnace, or by lowering the valve 25 and raising the valve 9 according to Fig. 4, causing the material to slide down around the wall 2! of the furnace A. In order to protect the wall against wear thereis a lining IS.

The distributor l4, which is fixed in the upper part of the furnace is adapted to guide the material out against the wall 2!, as shown in Fig. 4. The valve member 25 and the distributor l4 carry members i? on the upward surfaces thereof forming radially extending ribs for guiding the stock flow thereover. A cylindrical member 15 is provided interiorly of the upper portion of the furnace wall 2| adjacent to the distributor I 4 in order to provide a wear resistant surface upon which the stock. flowing outwardly over the distributor may impinge. In the embodiment illustrated in the drawing the distributor I4 is extended downwardly with a cylindrical part l8 so that an annular space I9 is formed for guiding the charge.

Fig. 2 shows in detail firstly how the valve 9 tightly engages the bottom 16 of the container, secondly how the valve 25 fits into the valve" 9 and thirdly that the valve 25 may unimpededly be lowered through the opening in the bottom i6 of the container B.

In the shown embodiment the valve 9 is operated by the compressed air container H], the lever H with its counter-weight l2 and the hollow rod l3. The valve 25 is operated by the compressed air container 25, the lever 21 with 4 its counter-weight 28 and rod 29. The gas outlets from the furnace are designated 22. 23 is a safety valve.

Naturally the valves may also be operated by some other means, for instance hydraulically, by means of electrically driven hoists, etc., or manually.

Having now particularly described the nature of our invention and the manner of its operation what we claim is:

1. A charging device for a shaft furnace comprising a charging top and a stationary conical guide having a central opening therein affixed to the upper part of the furnace below the charging top and independently of the charging top, said charging top including a bottom portion in the form of an inverted cone having an opening in the bottom thereof, a closure for said charging top opening including an upper conical valve member, and a lower conical valve member arranged below the upper conical valve member, said valve members being adapted to be raised and lowered independently of each other, the upper valve member being of larger diameter than the opening in the charging top and being adapted to seal the opening when in engagement with the rim thereof, and the lower valve member being of smaller diameter than the opening in the bottom of the charging top so that, when the upper valve member is raised above said opening, said lower valve member can be selectively raised above said opening or lowered below said opening independently of said upper valve member, said lower valve member being of smaller diameter than the opening in the stationary conical guide, said lower valve memher and said stationary conical guide both including a plurality of radially extending guide ribs on their upper surfaces for guiding material in flow thereover and said stationary guide including a cylindrical extension projecting downwardly from its outer periphery, the diameter of the cylindrical extension of the stationary guide being substantially greater than the diameter of the central opening in the stationary guide, a cylindrical member mounted on the interior surface of the upper end of the furnace Wall adjacent to the cylindrical extension of said stationary conical guide, said stationary conical guide and cylindrical extension forming the inner wall and said cylindrical member forming the outer wall of an annular space within the upper part of the furnace, said conical guide being so positioned that said lower valve memher, when lowered to a position below the opening in the bottom of the charging top and to the level of the top of the conical guide, coopcrates with the conical guide for feeding material down through the annular space around the conical guide, and said lower valve member, when raised to a position above the opening in the bottom of the charging top, cooperates with the bottom of the charging top for feeding material through the central passageway in the conical guide.

2. A charging device for a shaft furnace comprising a charging top and a stationary conical guide having a central opening therein aflixed to the upper part of the furnace below the charging top and independently of the charging top, said charging top including a bottom portion in the form of an inverted cone having an opening in the bottom thereof, a closure for said charging top opening including an upper conical valve member. and a lower conical valve member arranged below the upper conical valve member, said valve members being adapted to be raised and lowered independently of each other, the upper valve member being of larger diameter than the opening in the charging top and being adapted to seal the opening when in engagement with the rim thereof, and the lower valve member being of smaller diameter than the opening in the bottom of the charging top so that, when the upper valve member is raised above said opening, said lower valve member can be selectively raised above said opening or lowered below said opening independently of said upper valve member, said lower valve member being of smaller diameter than the opening in the stationary conical guide, said lower valve member and said stationary conical guide both including a plurality of radially extending guide ribs on their upper surfaces for guiding material in flow thereover and said stationary guide including a cylindrical extension projecting downwardly from its outer periphery, the diameter of the cylindrical extension of the stationary guide being approximately twice the diameter of the central opening in the stationary guide, a cylindrical member mounted on the interior surface of the upper end of the furnace wall adjacent to the cylindrical extension of said stationary conical guide, said stationary conical guide and cylindrical extension forming the inner wall and said cylindrical member forming the outer wall of an annular space within the upper part of the furnace, said conical guide being so positioned that said lower valve member, when lowered to a position below the opening in the bottom of the charging top and to the level of the top of the conical guide, cooperates with the conical guide for feeding material down through the annular space around the conical guide, and said lower valve member, when raised to a position above the opening in the bottom of the charging top, cooperates with the bottom of the charging top for feeding material through the central passageway in the conical guide.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 809,754 Shackleford Jan. 9, 1906 864,053 Witherbee et a1. Aug. 20, 1907 967,328 Collord Aug. 16, 1910 1,333,957 Bird Mar. 16, 1920