US3508671A - Blast furnace skip car - Google Patents

Description

April 1970 D. J. LEACH ETAL 3,508,671

BLAST FURNACE SKIP CAR Filed Feb. 6. 1969 lNVENTOR/S DONALD J LEACH W/LL/AM N. Moo/25 B/LLV .J'. SNYDER United States Patent 3,508,671 BLAST FURNACE SKIP CAR Donald J. Leach, William N. Moore, and Billy J. Snyder, Ashland, Ky., assignors to Armco Steel Corporation, Middletown, Ohio, a corporation of Ohio Filed Feb. 6, 1969, Ser. No. 797,101 Int. Cl. F27b 11/12 U.S. Cl. 214-19 4 Claims ABSTRACT OF THE DISCLOSURE A skip car for delivering a blast furnace charge comprising a primary chamber and a secondary chamber in the form of a chute communicating with the primary chamber. The respective chambers are so arranged that when they are positioned at the dump angle, the material contained in the secondary chamber will pass into the primary chamber and into the furnaces charge receiving hopper.

BACKGROUND OF THE INVENTION The blast furnace process, the primary method in producing pig iron, comprises charging large quantities of iron ore, coke, and limestone into the top of a shaft furnace while blowing hot air into the bottom. With the exception of periodic shut-down, the process is continuous.

In order to carry on this operation in a continuous manner, a regular schedule for charging must be maintained. To accomplish this, the blast furnace is provided with an inclined skip bridge which carries and directs the skip cars or charging buckets to the top of the furnace. Typically, two skip cars are operated in a reciprocating fashion. That is, when one is being filled with charge materials, the other is dumping. By this procedure, a regular charging schedule is maintained.

One problem in carrying out this generally automated operation was discovered at the skip car filling or charging station. Delays in charging or extensive maintenance resulted in a loss of time in producing the pig iron.

Typically, the charging station is a pit out of which tracks lead for carrying the skip car to the furnace top. For filling or charging, the skip cars are positioned in the pit beneath a series of bins containing iron ore, coke and limestone respectively. By means of metering or weighing mechanism, the charged materials are transferred from the bins, through chutes, and into the skip car. Due to the rapidity and quantity of the charge, some materials were misdirected and a build up resulted in the bottom of the skip pit. This build up or accumulation had to be removed periodically in order to continue the normal charging operation.

With the skip cars used heretofore, it was virtually impossible to clean up the pit area without causing a serious delay in the furnaces operation. Due to the depth of the pit and the size of the skip car, the accumulated material could not be easily shoveled into the broad opening of the skip car. In an attempt to overcome this operational problem, a special clean up door was proposed for the skip car. This, however, met with maintenance problems in its own right, as well as continuing with a delay in the operation.

With the structure proposed herein, an economical and eflicient clean-up system has been found which solves the enumerated problems without causing unnecessary delays in the furnaces operation.

SUMMARY OF THE INVENTION Briefly, in the practice of this invention, a skip car for delivering a blast furnace charge to the top of said furnace by means of an inclined skip bridge is provided with a secondary chamber in the form of a chute. The chamber is located on the side remote from said skip bridge. The chute has an external opening intermediate said remote side, and an internal opening providing communication with the skip cars primary chamber.

By the positioning of the chute in this maner, accumulated pit material may be readily shoveled into the opening thereof. The vibrating action of the ascending skip car, and the pivotal action by the lifting of the bail hoist, causes the shoveled material to pass into the primary chamber and eventually into the receiving hopper of the furnace.

BRIEF DESCRIPTION OF DRAWINGS FIGURE 1 is a simplified schematic drawing of a blast furnace plant showing the skip car of this invention in the loading and discharging positions.

FIGURE 2 is an enlarged sectional view of a skip car constructed in accordance with the teachings herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to a description of the preferred embodiment, reference is made to FIGURE 1 wherein there is shown a schematic presentation of a blast furnace plant utilizing the invention disclosed herein.

While it should be evident that details may vary from one operation to another, certain basic features are common to each. Basically, in each blast furnace plant a shaft type furnace 10 is provided with means 12 at its top for receiving a charge of material. Typically, this may comprise a receiving hopper 14 and a distributor 16.

The charge is brought to the receiving hopper 14 by a skip car 18 along an inclined skip bridge 20. The base of the skip bridge 20 leaves from a pit 22 disposed below a series of bins 24 containing the charge materials. One of the problems encountered in operating a blast furnace plant is in the area of controlling the feed from the bin 24.

The normal furnace charging procedure consists of a frequent and regular charging schedule achieved by the reciprocal action of two skip cars, which cars operate on a common cable mechanism. That is, as one is dumping it sload into the receiving hopper 14 (see FIGURE 1), the other is being loaded into the pit 22. With this completed, the second car moves up the skip bridge 20 to the top of the furnace 10, while the first car moves down to the pit 22.

As simple as this changing procedure may appear, problems have developed with the accumulation of charging mterials in the pit 22. The build-up, due to misdirected material from the bins 24, interferes with the normal charging procedure and ultimately causes delays in the furnace operation. For example, if too much accumulated material were present in the pit preventing the charging car to rest in the lowermost position, the dumping car would not be fully pivoted for feeding into the receiving hopper. Additionally, the skip cars may become derailed causing further shut-downs in the furnaces operation. Heretofore, scheduled interruptions were made in order to clean up the pit area. Special skip cars or the use of automatic equipment were required. Such clean-up procedures were costly, time consuming and generally unsatisfactory.

The present invention has developed an economical and dependable pit clean-up system which uses a unique skip car 18. This skip car, best shown in section in FIG- URE 2, comprises a primary chamber 18a having a base 26, vertically disposed peripheral walls 28 and 28b, and a charge receiving opening 30. Adjacent one of said walls 28b, there is provided a secondary chamber 18b, in the form of a chute, which communicates at 32 with the primary chamber along the base 26 thereof. The typical skip car used today has a capacity on the order of about 375 cubic feet, and has a width of from 6 to 8 feet. With a skip car of this size, the secondary chamber 18b is small in comparison with the primary chamber. For instance, the external opening may be only several inches by 6 to 8 feet. And, since the opening is near the bottom of the primary chamber, its relative capacity is likewise small.

It will be apparent from this unique design that the clean-up mechanism has been made part of the skip car. This can be either by initial construction or an adaptation of an existing skip car. But in each case an effective way has been found to help in the removal of the accumulated charge material.

In the past it was impossible to manually shovel the clean up material from the pit into the charge opening 30 of the skip car because the charge opening could be as high as 20 feet above the floor level. As a means to help visualize this problem, it is sufiicient to say that the typical skip car is large enough to hold a standard automobile. While trap doors were proposed to overcome the aforementioned problem, the doors could not be opened during the material charging from above. With the skip car design such as proposed herein, clean-up delays have been eliminated. It is anticipated that with the present invention the charging of the blast furnace will not be interrupted for clean-up maintenance.

In operation, the secondary chamber 18b acts as a chute to divert shoveled material into the bottom of the primary chamber 13a of the skip car until said primary chamber is filled from said bins. Once loaded, the chute acts as a supplementary container for any remaining excess material. When the skip car reaches the top of the furnace and pivots, by means of a bail hoist 19, to be emptied into the receiving hopper 14, the respective chambers are readily emptied.

In the preferred embodiment, the vibrating action of the descending skip car down the skip bridge causes any of the material that may have failed to dump from the secondary chamber to be vibrated into the primary chamber where the material will be dumped with the next load to the top. To assure this self-cleaning feature, the depth of the opening at 32 may be made slightly larger than the opening into 18b so that any material that goes into the secondary chamber can dump through the opening into the primary chamber. While this is the preferred dumping procedure, it is contemplated that the 4 respective chambers are independent and without an opening 32. In this situation, it may be desirable to angle the wall 28!: toward wall 28a so as to assist the dumping of the shoveled material over wall 28b into the receiving hopper 14; also, the opening would be in the top of the secondary chamber 18b.

While wheels 34 have been illustrated to show the manner by which the cars move along the inclined skip bridge, they form no limitation on this invention. Their construction and manner for securing same to the body 18 are well known features. It is therefore suificient to say that this invention contemplates some means for facilitating the reciprocating movement of the skip cars.

While the description of this invention has been directed to the preferred embodiment, no restrictions are intended on the design of this invention since modifications may be made therein without departing from the spirit of this invention.

The embodiments of the invention which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for carrying a blast furnace charge along an inclined path from a lower position to an upper posi tion where said charge is dumped, comprising in combination, a vehicle body composed of a primary chamber having a base, vertically disposed walls and a chargereceiving opening, and a smaller secondary chamber adjacent one of said walls, said secondary chamber having a charge receiving opening disposed beneath said primary chamber opening, and means for moving said vehicle body along said inclined path.

2. The apparatus claimed in claim 1 including an internal opening between said chambers along said base.

3. The apparatus claimed in claim 2 wherein the capacity of said secondary chamber is less than the capacity of the primary chamber.

4. The apparatus claimed in claim 3 wherein said charge receiving opening in said secondary chamber is equal to the width of the vehicle body.

References Cited UNITED STATES PATENTS ROBERT G. SHERIDAN, Primary Examiner US. Cl. X.R. 198-l 03

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