US630682A - Apparatus for regulating temperature of heated air. - Google Patents

Description

Nnr630,682. Patented Aug. 8, I899.

L. F. GJERS &. J. H. HARRISON.

APPARATUS FOR REGULATING TEMPERATURE OF HEATED AIR.

(Application filed May 2, 1898.) (No M de! 2 Sheats$heet I.

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No. 630,682. Patented Aug. 8, I899.

L. F. GJERS Q. J. H. HARRISON.

APPARATUS FOR REGULATING TEMPERATURE OF HEATED AIR.

(Application filtl May 2, 1898.) (No Model.)

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UNITED STA S PATENT OFFICE.

LAWRENCE FARRAR GJERS AND JOSEPH HUTCHINSON HARRISON, OF MIDDLESBROUGH, ENGLAND.

APPARATUS FOR REGULATING TEMPERATURE OF HEATED AIR.

SPECIFICATION" forming part of Letters Patent No. 630,682, dated August 8, 1899. Application filed May 2; 1898. Serial No. 679,518. (No model.)

in Belgium, No. 136,065, dated May 23, 1898,

and in France, No. 278,144, dated May 21, 1898,) of which the following is a specification.

As is well known, the air-blast of ironsmelting furnaces is usually heated by means of reversible regenerative stovessuchas.

Oowpers, Whitwells, Ford & Moncurs,and

others-which are lined with fire-brick 'andprovided internally with open checker-work of fire-brick arranged so as to leave spaces between and among the bricks, two or more of these stoves being worked alternately in such a way that while one is beingheated by, the combustion of waste gases from the fur-, nace orby other means another having been heated is used for heating the blast which is passed through it on its way to the furnace.

It is obvious that from the time the blast is directed into a freshly heated. stove to' the time when it is directed into another stove the temperature of the saidrblast will gradually.

decrease, and also that when the blast is again directed into another freshly-heated stove its temperature will suddenly rise, the difference in temperaturesoften amounting in practice to from about .to 150 centigrade, (150 to 300 Fahrenheit.) i

It is now generally admitted that blastfurnaces work much more irregularly when regenerative stoves of the kind mentioned are used for heating the blast than when the older cast-iron pipe-stoves are used through which air and hot gasesare separately passed in a continuous manner and in which the blast is heated to an approximately uniform degree. Regenerative stoves, however, possess the advantage of being able to heat the air-blast to a much higher temperature than is possible with the older pipe-stove, which results in a reduced fuel consumption in the furnace. When using regenerative stoves, however, the smelting materials in the blastfurnace very frequently form scaffolds or ledges of partly-fused material that stick to the sides of the furnace and prevent proper descent of the charge to the hearth or: crucible below. Sometimes very great trouble is experienced in removing such scaffolds. In other cases, on account of the melting and withdrawal of the portion ofthe charge below and the increasing weight of the charge above, the obstruction frequently gives way suddenly, thereby causing a rapid descent of the upper portion of the charge, technically called a slip, into the hearth below. Mean- ,while, the proper working of the furnace is not only interfered with, but there is little or no gas formed to supply the steam-genera- 'tors and stoves used to supply and heat the blast with the result that the pressure and temperature of the blast decreaseat a time when the furnace requires the blast to be at its highest pressure and temperature; With the old form of pipe-stoves, on the contrary,

scaffolding and slipping rarely take place.

Investigation has shown that the irregularity in the working of blast-furnaces when regenerative stoves areused is due to, the variation in the temperature of the blast heated by such stoves. Higher temperature'of the blast produces quicker combustion of the fuel, With increased temperature in the vicinity of the twyers, anda consequently reduced height of melting zone, so that the partlyfused materials in the region slightly above the new melting zone stick together and form ascaffold, which is likely to be a very objectionable one when a very hot stove comes into use after a comparatively cold one. a

Now this invention has reference to means or apparatus whereby air or other gas heated by being passed through a regenerative stove or chamber of the kind hereinbefore referred to previously heated by the combustion therein of gases from a furnace can be maintained at a nearly uniform and high temperature notwithstanding that the temperature of the regenerative stove or chamber through which it is passed and in which it is heated is being gradually reduced. For this purpose there is provided in connection with regenerative stoves or chambers of the kind hereinbefore referred to a heat-equalizer, which is '1; may advantageously be of similar construction to an ordinary regenerative stove and through which the heated air orgas is passed after leaving each of the regenerative heatingstoves in turn and before it reaches the blast or other furnace or place to which it is to be supplied, the arrangement being such that the excess of heat taken up by the air or gas upon passing through a freshly-heated regenerative stove will be transferred to and stored in the heatequalizer to be subsequently given up to cooler air or gas that has passed through the stove after the same has been reduced in temperature, so that the air or gas delivered from the heat-equalizer to the furnace or other place will be at an approximately uniform temperature.

Figure 1 of the accompanying drawings illustrates diagrammatically in sectional plan an arrangement of combined blast-furnace 1, regenerative air-heating stoves 2 2 2", and heat-equalizer 3 according to this invention. Fig. 2 is a cross-section on the line a: at, Fig. 1.

The heat-equalizer 3 has an inlet4= in communication with a hot-blast main 5,into which hot air is delivered from each of the regenerative stoves 2 2 2 in turn, which are heated by the combustion therein of hot gases from the blast-furnace, as well understood, the connection between each stove and the main 5 being elfected through a branch pipe 5, controlled by a valve 5.

6 is a blowing-engine by which air is delivered through piping 7 alternately to each stove, the connection between each stove and the piping 7 being effected by a branch pipe '7 with a valve 7 8 is the outlet of the heat-equalizer in constant communication with the horseshoe hotblast main 9 of the furnace 1.

10 is a gas-main in constant communication, by means of a main 11, with the exit for hot gases from the top of the blast-furnace 1, the said main 10 being adapted to be placed in communication with each'of the regenerative stoves 2 2 2 by a branch pipe 12, provided with a valve 13.

14 is a main in constant communication with a chimney and also adapted to be placed in communication with each of the regenerative stoves 2 2 2 by means of apipe 15, provided with a valve 16. The arrangement is such that by closing the air-valves 5 and 7 and by opening the gas- valves 13 and 16 corresponding to any regenerative stove hot gases from the blast-furnace 1 can in a manner well understood be caused to flow through such stoves 2 and by their combustion therein with air heat the same and then pass into the main flue Maud chimney, after which by closing the gas-valves and opening the airvalves air from the blowing-engine 6 can be caused to pass through the heated regenerative stoves, and thence through the equalizer 3 to the furnace 1.

The heat-equalizer 3 shown is similar in construction to a regenerative stove and comprises an iron shell or casing lined with firebrick and containing open fire-brick checkerwork 3. It may consist of a single chamber or it may be divided Vertically into two or more sections or chambers. In the drawings it is shown divided into two sections by a division-wall 3 ,such chambers being connected together at the top, so that when the hot air from one of the stoves 2 2 2" enters at the inlet 45 it ascends one chamber and descends the other to the outlet 8 and the horseshoe hot-blast main 9, and thence to the furnace 1. Vhen the blast passes from one of the freshlyheated regenerative stoves at its highest temperature into the heat-equalizer 3, the portion of the checker-work in the latter with which it first comes into contact will be at a temperature corresponding approximately to the reduced temperature of the other stove. This blast will consequently give up some of its heat to the heat-equalizer and pass out to the furnace 1 at about a mean between the highest and lowest temperatures given by the stoves. \Vhen the temperature of the regenerative stove through which air for the time being is passing and consequently also that of the blast decreases, the heat-equalizer will give up some of its accumulated heat to the blast, which will thus pass out to the furnace with its temperature raised to about a mean between the highest and lowest temperatures given by the stoves. Thus it will be seen that during the first portion of a stoves run the heat-equalizer will absorb heat from the blast and during the latter portion of the run will give up this heat to the blast, after which the blast is directed through another regenerative stove that has in the meantime been heated, and the same process of absorbing and giving up heat repeated.

A further advantage gained by the use of a heat-equalizer according to this invention is that should the furnace work badly from any cause and there is little or no gas given ofi. therefrom to the stoves the stored-up heat in the heat-equalizer will prevent a sudden decrease in the temperature of the blast, which would otherwise occur.

It will be obvious that heat-equalizers such as described can also be used with stoves heated by flame and hot gases from special heating-furnaces instead of by the hot gases from blast-furnaces.

What We claim is ating substantially as hereinbefore described T0 In a hot-blast-furnace plant, the colnbinafor the purposes set forth. tion with a blast-furnace, air-heating stoves, Signed at2 Exchange Place,Midd1esbrough and means for causing air and hot gases to on-Tees, England,this 15th day of April, 1898. flow alternately through each of said stoves, LAWRENCE FARRAR GJERS. of a heat-equalizer arranged between and in JOSEPH HUTCHINSON HARRISON. communication with the blast-furnace and Witnesses: stoves and comprising a chamber charged RICHARD HOWSON, with refractory material arranged and oper- GEORGE J OBSON.

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