US1897750A - Method of blast furnace operation - Google Patents

Description

Feb. 14, 1933. H A. BRASSERT METHOD OF BLAST FURNACE OPERATION Filed Sept. 18

1931 2 Sheets-Sheet l v H. A. BRA$SERT METHOD OF BLAST FURNACE OPERATION Filed Sept. 18

1931 2 Sheets-Sheet 2 Patented Feb. 14, 1933" UNITED STATES PATENT OFFICE HERMAN A. BRASSERT, or CHICAGO, ILLINoIs, assrenon '10 II. A. ERAS-SE31 &

COMPANY, 01 CHICAGO, ILLINOIS, A CORPORATION or ILLINOIS mn'rnon or BLAs 'r FURNACE OPERATION Application filed September 18,1931. Serial No. 563,601.

This invention relates to a new and improved method of' blast furnace operation, and more particularly to a method for maintaining a substantially uniform top tem- 5 perature both as to gases and as to the upper layers of stock.

One of the chief defects in blast furnace operations comes from the fact that due to variation in the quality of the raw materials and their distribution in the furnace, and due to changes in the heat and moisture of the blast and other variables, the melting zone and the zones of reduction above are not maintained in the position established in normal eificient practice; and that by an extension of the melting zone upward into the reduction zone and a simultaneous rise in stack temperature, the relative position of the zones of direct and indirect reduc tion changes, unbalancing these important reactions and leading not only to uneconomic operations from the point of view of heat economy but often to hanging and slipping of the furnace. The flue dust losses which are concurrent with such irregularities are one of the greatest sources of monetary losses in furnace operations and can be.

' greatly decreased if it is possible to maintain the correct temperatures throughout the furnace stock.

With modern hot blast equipment it is possible to maintain the blast at a substantially even temperature, it is also possible to compensate for irregularities in the moisture of the blast by a corresponding increase or decrease in blast temperature; or the mois-- ture can be entirely eliminated through treating the blast by well known methods, but it is not possible to so control the physical and chemical quality of the raw materials that the heat reactions in the furnace will be uniform at all times. .These-irregularities will often cause an uneven distribution of the gases through the stack, including channeling of excessive quantities of gases through certainsections, for instance, up on the walls. This causes localrises in temperature, increasing the amount of flue dust in those regions by sweeping a portion of the fines up with the gas stream ascending with abnormally high velocities; I find that this condition can be counteracted and largely prevented if we can succeed in keeping the top temperatures of the furnace uniform, not only in respect to that of the gases but also to that of the materials in the top layers. Attempts have been made to accomplish this by adding varying amounts of water to the stock and the prac- 50 tice is old and well lqiown to add a certain amount of water to the ores before they are hoisted to the top of the furnace. This parti'cularly applies to fine ores which are wetted down for the purpose of preventing the fine: from blowing over and making flue us a This method has the disadvantage of being irregular and subject to the whim of the operator and furthermore, fulfilling its-pur- 7 pose in only a very limited manner by reason of the inability to uniformly distribute the water throughout the ore. It carries no possibility of uniform control of the top temperature. This control of the top temperature which is so important in order to avoid the aforesaid irregular'operations, I obtain by inJecting a'measured amount of water into the furnace top below the main charging bell in such a manner as todisso.

tribute it evenly over the entire charge and automatically controlling the amount of this water by the top temperature. In this manner I not only maintain a uniform temperature of the top gases but I also maintain a uniform temperature of the upper layers of the stock, the effect of which is carried down to'the lower zones with the result that I obtain progressively. uniform zones of reduction and finally a uniform melting zone.

It is an object of the present invention to provide a new and improved method of blast furnace operation.

It is a further object to provide a method of this character in-which the top temperatures may be maintained substantially uniform both as to gases and as to the top layers of stock.

It is an additional object to provide a method for accomplishing this result, which iii) "the 7 per layers of materia vzles 19 are valve 22. These upper portion of the furnace.

{h ther and further objects will appearas l the description proceed g 1' have shown a preferred embodiment of apparatus for" carrying out my improved method in the accompanying drawings in which f f f v Figure 1 is a fragmentary vertical section showing the top of a blast furnace with my invention applied thereto. 1

Figure 2 is atransverse section through the plane of the nozzles of Figure 1.

Figure 3 is a fragmentary plan view showing the control apparatus, and

ui d supply valve and control cylinder. in the drawings the blast furnace is shown as having an upper outwardly flaring por- 313101112 e ading to the oiitakes 13. The furnace is shown as provided with usual charging apparatus including the lower bell 14, upper bell 15, hopper 16, skip' 17 and skip ois't 18.

A plurality of tangentiallylocated nozprovided' extending into the upper flaring portion of the furnace. nozzles are all fed with fluid from a circular header 20 which is fed through pipe 21 from nozzles are adapted to discharge fluid into the upper portion of the mace to cool both the gases and the up- The automatic control provided comprises the heat responsive control member or bar 23 extending into the oiftake 13, as shown on Figure v '26, the tension of by screw 27; The

a linkwiththe pivoted nozzle 28 which is 'directed toward the two 30. The pipe 31 leads to.

3, so that it is afiected by-the heatof the gases passing up' through the ofl'take. The inner endof the bar 23 engages a pivoted arm 24 in housin 25, this arm 24 being held against the bar y sprin which may be adjusted arm 24 is connected by outlet pipes 29 and oil pump 32 which is ,driven by motor 33 and fed from oil reservoir 34. The oil re 5* 5 reservoir 34.

The valve 44 is adapted to co-act with turn pipe 35 leads from housing 25 to the The control cylinder and valve are shown piston37 connected by piston rod 38 to the arm 39. This arm is connected by'link 40 of September, 1931.

to the valve housing 41 and is also connected to yoke 42 which. is connected to valve stem the, valve seat 45. The cylinder 36 has the connection 46 to connect. pipe 30 at its up-- such as water orother den 36 against the under side of ifigure 4 is a fragmentary section through These b nozzle 28 from the major pressure'from the oil fiowing'from it swings the arm 26. The connecting e counter clockwise direction. The

nozzle 28 is thus directed into pipe 29 and V consequently into the lower portion of cyliniston 37. This pressure forces the piston 3 ly and through piston rod 38, arm 42' and valve stem 43, it lifts valve 44 from valve seat 45. This permits a flow of cooling fluid through pipe 21 to header 20 and thus through nozzles 19 by sprayed into'the top of the furnace.

Similarly when the gases in the 'ofitake 13 become cooled, the bar23 shrinks, the arm 24 is forced in a clockwise direction by spring 26, the nozzle 28 is swung in the clockwise direction and the heavier oil presupward-- 39, yoke which it is forced down against its seat off the flow of cooling fluid.

lit will be understood that the particular type 'of control which has been'shown is to e taken as illustrative only as my invention may be carried out in other ways and by other forms of control and I contemplate such changes and modifications as come within the spirit and scope of the appended claims. Y'Vhile ordinarily water will be the fluid used for discharge through the nozzles,

45, thus cutting it may be'found advisable to inject a certain amount of gas together with the water in order to increase the kinetic energy or centrifugal force of the revolving gases. This isfor the purpose of causing the dustto.

separate itself from the ath of the gases in accordance with the Elichenberg system for the prevention of flue dust.

I claim 1. The method of blast furnace operation which comprises injecting a cooling medium into the top of the furnace and controllm'g the injection of said medium by means responsive to the temperature of the gases at the top of the furnace;

2. The method of blast furnace operation which comprises spraying water at a plurality of points into the top of the furnace and controlling the water spray automatically y means responsive to the furnace top temperatures. 1

Signed at Chicago, Illinois, this15th day HERMAN A. BRASSERT.

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