US248484A - Regenerative hot-blast apparatus - Google Patents

Description

5 Sheets-Sheet 1.

(No Model.)

J. 0,. LONG.

REGBNERATIVE HOT BLAST APPARATUS.

Patented 081:. 18,,1881.

lllvl'lll Invenior; 0mm (1.170819 i J y M- f I (N0 Model.) 5 Sheets-Sh'eet 2.

J. 0. LONG.

REGENERATIVE HOT BLAST APPARATUS. No. 248,484. 8 Patented Oct. 18,1881.

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NlTED STATES PATENT OFFICE.

JOHN 0. LONG, OF MEGHAN'IOSBURG, PENNSYLVANIA.

REGENERATIVE HOT-BLAST APPARATUS.

SPECIFICATION forming part of Letters Patent No. 248,484, dated October 18, 1881.

(No model.)

To all whom it may concern:

Be it known that I, JOHN C. LONG, a citizen ofthe United States,residingat Mechanicsburg, in the county of Cumberland, and State of Pennsylvania, have invented new and useful Improvements in Hot-Blast Ovens, ofwhich the following is a specification.

This invention relates to certain improvements in regenerative hot-blast apparatus for heating'a blast of air, gases, or vapor to be supplied to metallurgical furnaces for intensifying the action therein.

Heretofore it has been customary to heat regenerative hot-blast apparatus by burning therein combustible gashavinga temperature equal to that which it has when leaving the blast-furnace or other source of supply less that lost during its passage to the hotblast apparatus. This temperature in the case ofthe waste gases of the blast-furnace is about 300 or 4.00 as it leaves the furnace, less the loss of transmission. The air used for combustion is drawn into the apparatus by means ofthe draft of a very high chimney, and is used at the temperature of the atmosphere, except in one casein which it is claimed to be heated by passing through passages or channels in the partition-walls of the apparatus.

The above methods are objectionable because the temperature or intensity of the heat of the blast is limited, on account of using the combustible gas at so low a temperature and burning it with airdrawn in byatall chimney, by which means no intense combustion of the gas or proper distribution of the products of combustion can be produced. Further, on account of the method of heating the air for combustiou it is evident that it can attain no very great temperature, as the passage in which it is heated cannot be made sufficiently large. The quantity of air necessary for combustion bears quite alarge ratio to the quantity of blast that an oven can heat, and it is manifest the surfaces of the passages do not bear a similar ratio to the surfaces of the lines of the oven.

The object of my invention is to provide a regenerative hot-blast apparatus by means of which a blast of air, gases, or vapors may be obtained whose temperature is only limited by the resistance of the refractory materials coniposing the apparatus, thus greatly facilitating and economizing metallurgical operations now employed and rendering useful some heretofore considered impracticable. In most metallurgical operations it is a great intensity of heator temperature thatis desired; for a metal may be exposed to any quantity of heat without fusing, provided the temperature be below its fusing-point, while on the contrary a short exposure to a temperature but slightly above its melting-point will fuse it, although in the latter case itis exposed to a much smaller quantity of heat, but that of greater intensity, hence greatly economizing fuel and facilitating the operation; and, as in the blast-furnace, the quantity of fuel over and above that necessary to reduce the ore and carbonize the metal is used, mainly, for fusing the metal and slag, it follows that the more intensely the blast is heated the less fuel it will be necessary to burn in the hearth of the furnace, and as a blast can he produced by my apparatus whose temperature is only limited by the resistance of the refractory materials of the ovens, hence by its use ablast-furnacecan be worked nearer the theoretical minimum of fuel than heretofore, and as a consequence of the decrease in the fuel the necessary air supply is also reduced and the working capacity of thefurnace increased, owing to the greater space for charges otherthan fuel, thus materially reducing the cost of production. By using a very intensely heated blast greater control of the furnace is obtained and more refractory ores and fluxes can be used, thus making valuable heretofore useless materials.

To this end the invention consists in the combination, with the peculiarly-constructed ovens in which the blast of air, gases, or vapors are heated prior to passing to the furnace, of similar supplementary ovens or heaters for heating the combustible gas which is subsequently burned in both the blast-ovens and gas-heater, for the purpose of intensely heating them, as is more fully explained hereinafter; and it also consistsin the connections by which the gas-heaters are connected to the ovens and with each other, whereby the highly-heated combustible gas may be introduced into the oven or gas-heaters to be burned therein and it further consists in introducing into the ovens and gasheaters of a forced blastof highly-heated air from the hotblast main or parts in free communication with it, thus burning the combustible gases therein by a forced hot blast to intensify the combustion thereof, and produce an equable distribution of the hot products of combustion and a more equal heating of the ovens and heaters, and at the same time decreasing the. amount of draft necessary to be produced bythe chim ney; and italso consists of the air-connections employed for this purpose.

In the drawings, Figure 1 represents a vertical longitudinal section through the ovenconnection and gas-heater, showing the valves closed and the manner of forming the ovens, gas-heaters,and the arrangingof thefiuesinto a set in a decreasing series from the combustion-chambers and the top and bottom chambers or flues,and method of removing thedust. Fig. 2 represents aliorizontal section on the line arm of Fig. 1, showing the combustiblegas connection and the cold-blast and chimneyconnections. Fig. 3 represents a horizontal section on the line 3 y of Fig. 1, showing the hot-air connections and form of the oven and heaters. Fig. 4 represents a transverse vertical section through the combustion-chainber of the ovens on the line 3 of Fig. 3, showing their construction. Fig. 5 represents a transverse vertical section through the combastion-chamber of the gasheaters on the line z z of Fig. 3.

In carrying out the invention, where a continuous blast is desired at least two ovens are employed for heating the blast supplied to the furnace. In connection with the ovens, as above, two or more gas-heaters are used, and in a similar manner to the ovens, as above.

In the following description but two ovens for heating the blast are combined with two gas-heaters for heating the combustible gas.

The letters B B indicate the ovens for heating the blast, and are rectangular in form and constructed of tirebrick or other suitable refractory materials, and whose walls are supported by circular or elliptical segmental walls of ordinary brick-work and incased with sheetiron, or the space between the oven and the sluet-iron casing may be filled with cinder, loam, or broken bricks, &c. The sheetiron casing is suitably strengthened at the angles to resist the strain put upon it by the pressure of the blast and the expansion of the oven. The roof is also covered with sheetiron, put on in strips corresponding with the width of the roofs of the fines and having upturned flange-like edges bolted together or held down in place by girders passing over the middle of each flue and fastened at each end to the side casing of the oven. The interior of each oven is divided into two partsviz., D the combustion-chamber, and C the regeneratorby the wall B which extends from the bottom to near the top, only allowing sufficient room for the horizontal flue H The lower part of the combustion chamber D is contracted by the walls E Fig. 4, which are run up square to the level of the perforated air-cylinder O and blocks S and from thence they rapidly taper off, for the purpose of producing a more perfect combustion of the gas and for increasing the draft by means of the divergingjets of air from the cylinders and blocks, as well as evenly distributing the flame and gaseous products of combustion to the several independent compartments of the oven hereinafter mentioned. The upper termination of the tapering wall is indicated by line d in Fig. 1. The air-cylinder 0 is placed in the combustion-chamber D' so that it shall be midway between the airblocks S at the angle of the side walls, E in order to divide the combustible gas equally. The cylinder is perforated by a number of circular holes, P, Fig. 4, so arranged that no two adjacent ones shall be in the same vertical plane, thus. as it were, breakingjoints, so that thejets of air issuing therefrom shall have different vertical angles, the lower ones being horizontal, or nearly so,the others at different angles, so as to equally distribute the flame throughout the chamber 1)". The air-blocks S are placed at the angles of the walls E'Zand are provided with holesarranged in a similar manner to those in the cylinder butso that thejetsissuingfrom them shall not strike those from the cylinder 0 but shall pass between or inter-lace with them, thus having the ascending combustible gas divided by the cylinder O and each current passing between two series of air-jets, by the lower of which the gas is mixed with air, and then burned by the upper ones, thus having it consumed under circumstances the most favorable for the production of a most intense heat.

The cylinder 0 and air-blocks S com municate with the hot-air main L or parts in free communication with it by means of the pipes P in the former case and the several pipes T in the latter, having the regulatingvalves 1t and U respectively, which, when once properly set, always remain open during the operation of the oven, both when it is heating the blast and when it is burning gas. The airblocks lying on the adjacent sides of the ovens may be connected directly by the pipe S having valve S which is operated similar to It".

The lower part of the chamber 1) is provided with an opening for the hot-blast and hot-gas connection M and for cold-gas connection V as well as the opening M for the removal of dust.

The upper part of the combustion-chamber 1) is provided with a series of flues, E, Fig. 4, communicating with the regenerator C and formed by the roof-supporting partition-walls,

which walls extend from the front to the back and from the top to the bottom of the ovens, except in the combustion-chamber D in which they extend only to the top of the sloping walls E The oven is thus divided into several independent compartments, which, in the regenerator C are divided by the walls F into flues E arranged in sets forming a decreasing series from the combustion-chamber D and the spaces H and l at the top and J and K at the bottoms are formed by having the walls F to neither reach the top or bottom except in that forming the last line of the first set, which extends to the top, and that forming the last flue of the second set, which extends to the bottom, thus, for example, having four fines in first set, three in the second, and two in the third set, and forming a decreasing series from the combustion-chamber or an increasing series from the cold end; and as the gaseous products of combustion contract while cooling the surfaces over which they pass and impart their heat, as well as the capacity of the passages and absorbing materials, decrease in proportion, and, conversely, as the blast expands as -it is heated the capacity of the passages and heat-imparting materials and surface over which it passes increases, thus in either casemaintaining a uniform velocity, and having the 7 ing of the oven and distribution of the blast to be heated, and consequently very greatly increasing the efticiency ot' the apparatus.

The letter M indicates a small transverse channel in the inverted circular bottom of the chambers J and K extending through the oven and closed by suitable doors or meansat the sides of the oven,for the purpose of removing the dust. Similaropening is made in the combustion-chamber D The lower parts of each last set of fines in the several independent compartments communicate with each other and also communicate with the chimney D by'means of the openings T in the walls L, and the connections H and the pipe G which is provided with the valve 1 by which means communication can be cut oti' or estab-.

lished at will. They also communicate with the cold-blast-supply pipe K by openings T connection H and cold-blast pipe K having valve L by which communication can be es tablished or cut off at will.

The ovens or combustion-chambers 1) communicate with the hot-gas-supply main E by means of the pipe M provided with valve N, for the purpose of receiving hot gas for combustion, and with the hot-blast main L, by

means ot'the pipe M vertical pipe U, and provided with the valve 0 and branch B for the purpose of carrying the hot blast from the oven;

- to the hot-blast main L.

they are made smaller by decreasing the number of lines.

Thecombustion-chambermaybeconstructed like those of the ovens. or they may be made with either the air-cylinders or air-block alone. In any case their connection to the hot-air main -t'or receiving hot air for combustion is made by pipes R, having valves T, or pipe N, having valve 0, by which communication can be established orcut off at will.

Theletter E indicates the hot-gas main, into which the gas-heaters deliver the gas which they have heated through the hot-gas-connection pipe G, provided with the valve H, by which communication can be established or cut off. The gas-heaters also communicate with the main E by means of the pipes F F, having the valves H, by which the ovens can be supplied with hot gas for combustion when they are being heated. The hot gas for combnstion may be supplied directly from one heater to the other by means of the pipe I, having regulating-valve K extending from the combustion-chamber of one gas-heater to that of the other. The valve K, in this case, after being properly set, always remains open. The combustion-chambers B are also connected with cold-gas-supply main T by means of pipe V, having valve X. The gas-heaters are connected with the chimney D, means of the connection P, valve It, horizontal pipe W, having valve A and connecting with "ertical pipe 13 and hoiizontal pipe C. They are also connected with the cold-gas-supply main T, for the purpose of receiving the gas to be heated by means of the pipe S, valve R, and connection P.

In practice at least two gas-heaters are used, in combination with at least two ovens for heating the blast, but in case where the apparatus is used for heating anything but air it will be necessary to use a set of two supplementary ovens to heat the air for combustion and havingan additional hot-air main and connections, it it is desired to have hot air for burning the combustible gas.

WVhen heating a blast of air and heating'both the ovens and heaters by burning hot gas with hot air the operation is as follows, all valves being closed: In oven B open the cold-blast valve L by which cold air is admitted and passes through the compartments and series of tines to the combustion-chamber, then open the hot-blast valve 0 allowing the air to pass into the hot-blast main L, and thence tothe blastfurnace. Then in gas-heater Aopen thecoldgas valve R and the hot-gas-connection valve H, by which means we have gas admitted and passing through the separate compartments and dues and into the hot-gas main E. Then in oven B open the chimney-valve I and the hot-gas-supply valve N to admit gas into the combnstion-chamber, and open the valve R on the pipe I, and valves U on pipe T to supply air for burning the gas, which is then ignited. Theregulating-valves R and U when propetly set,always remain open. Thenin gasheater A open the chimney-valve A and the valves T on the pipes R, to supply air for combustion. Then open the hot-gas-supply valve H, to admit combustible gas from the main E, and ignite; or the gas can be supplied directly from one heater to the other by means of the pipe I, by opening the regulating-valve K, which, when properly set, remains open. The products of combustion pass through the compartments and flues to the chimney D by pipes \V, '1 and C. Now, after a longer or shorter intervaL-that is, until both the oven B and gas-heater A have become heated to a suflicient degree-the ovens and heaters are reversed at the same interval, or the ovens at one time and the heaters at another, depending on the wishes of the operator. Supposing that the reversal is at the same interval, proceed as follows: In oven B close the hot-gas valve N and the smoke or chimney valve 1, and open the cold-blast valve L and open the hot-air or blast valve 0 by which means we have hot air passing into main L. Then in oven B close the hot-blast valve G and the cold blast valve L and open the chimneyvalve 1 and the hot-gas valve N", and the regulating-valves U and R on the pipes T and P which, when properly set, always retnain open, both when the oven is heating blast or being heated by burning gas. Then in gas-heater A close the air-supply valves T and the hot-gas-supply valve H, if combustible gas is admitted that way. Then close the chimney-valve A and open the cold-gas supply valve It and the gas-connection valve H, thus introducing hot gas into the hot-gas tnain E. Then in gas-heater A close the cold-gas-snpply valve It and open the chimney-valve A and close the hot-gasconnection valve H and open the hot-gas-snpply valve B, if gas tor hurningis supplied in that way, and then open the air-supply valves 0. In the subsequent reversals proceed in the same way, the length of the intervals between which, after the apparatus is in full operation, depends on the time that it takes for the ovens and gas-heaters to become sufficiently heated and that required for them to part with their effective heat. It also depends upon the temperature of the blast desired. Bel'ore the first reversal, oven B and gas-heater A were heated by means of cold gas burned with cold air, but atter the first reversal the gas passing through the gas-heater A and the air passing through the oven B are both heated several hundred degrees; hence gas-heater A and oven B are being heated by burning hot gas by hot air, thus acquiring in an equal interval a temperature several hundred degrees hotter than oven B and gas-heater A did by burning cold gas with cold air. Now, after a second reversal we have the gas-heater A and oven B supplying air and gas several hundred degrees hotter than heater A and oven B did, and consequently heater A and oven B in an equal interval, by the combustion of this more highly heated gas with the more highly heated air, become several hundred degrees hotter yet, and after reversal furnish still hotter air and gas, and so on after each reversal hotter gas is burned with hotter air, thus developing a temperature of blast which is only limited by the resistance of the refractory materials composing the apparatus.

By properly proportioning the quantity of blast to be heated to the size of the ovens and gas-heaters and quantity of gas to be heated, and regulating the intervals between reversals, any temperature of blast can be maintained provided it be not beyond the resistance of the materials, or the temperature may be varied by the operator as demanded by the exigencies of the metallurgical operations.

The gas-heaters are all so arranged that they can be supplied with cold gas for combustion from the main T by means of the branch or pipe V having the valve X. In this case the valve K on the connecting-pipe I is closed, and the method of operating is the same as when the gas for combustion was obtained from the hot-gas main E by means of the valve I1, excepting that the valve X is used in place of valve II. It it is desired a mixture of hot and cold gas can be used by having the valve K partially opened.

The ovens are all so arranged that they can burn cold gas in connection with hot air. The cold gas is supplied frotn the cold-gas main T by the branch V provided with the valve W, and in the reversals the valve W is substituted for the hot-gas valve N but otherwise itis the same. They can also be run on a mixture of hot and cold gas, and in this case it is necessary to use both of the valves W- and N to admit the gas.

When using cold gas the gas-heating part of the apparatus may be done away with, or held in reserve in case an intensely-hot blast is desired, as when the blast-fnrnace is working cold attd badly.

Vhat I claim is-- 1. In a regenerative hot-blast apparatus for heating a blast of air, gases, or vapors to be supplied to metallurgical furnaces, the combination, with the principal ovens for heating the blast, of one or more gas-heaters or supplementary ovens for heating the combustible gas prior to its being burned in the principal oven and the gas-heaters, substantially as and for the purpose set forth.

2. In a regenerative hot-blast apparatus, substantially as described, the combination, with the ovens, of one or more gas heaters and a hot-air main connected to said ovens and gasheaters, whereby a forced blast of hot air may be supplied to the burning gas therein to intensify their combustion and thus heat them most intensely, and also to increase the flow of the products of combustion through the oven and gas-heater and thus decrease the chimney-draft necessary, essentially as and for the purpose specified.

3. Inaregenerativehot-blast apparatus,sub-

stantially as described, the combination, with the ovens, of a hot-air main connected to said ovens, whereby a forced blast of hot-air may be. supplied to the burning gases to intensify the combustion therein and most intensely heat them to increase the flow of the products of combustion and to lessen the chimney necessary, essentially as and for the purpose specifled.

4- In a regenerative hot-blast apparatus, the combination, with the ovens, of thegas-heaters, hot-air main, and hot-gas main connected to said ovens and gas heaters, whereby intensely-hot combustible gas may be supplied to the ovens and gas-heatersto be burned therein by a forced hot-blast to heat the ovens and gas-heaters, substantially as and for the purpose specified.

5. In a regenerative hot-blast apparatus, the combination, with the ovens, of the gas-heaters and a hotgas main connected to said ovens and gas-heaters,whereby inten sely-heated combustible gas may be supplied to said ovens and heaters to be burned therein, and thereby intenselyheat the said oven,substantially as and for the purposes specified.

6. In a regenerative hot-blast apparatus, the combination, with the ovens, of the gas-heaters and the cold-gas connection, whereby combustible gas may be heated and supplied to ovens and gas-heaters, and an intensely-heated blast supplied to the furnace, substantially as and for the purpose specified. V

7. In a regenerative hot-blast apparatus, the combination, with the ovens B B and the gasheaters A A, of the cold gas main T and branches S, V, and V and their valves, and the hot-gas main E, and branches F and G and their valves, and the hot-air main L, and the several connections T, T, W, P and N, and their valves, and the smoke-main leading to the chimney D, whereby air and gas for combustion may be supplied to said heater for burning therein, or combustible gas may be passed through said heater, by which means it is intensely heated prior to passing to the ovens and gas heaters to be burned therein, substantially as and for the purpose specified.

8. In a regenerative hot-blast apparatus, the combination, with the ovens B B and gasheaters A A, the cold-gas main T and branches, the hotgas main E and branches, the pipes G2 and K and the pipes M U and their respective valves, and the main L, whereby an intenselyheated blast may be supplied to a metallurgical furnace, substantially as and for the purpose specified.

9. In a regenerative hotblast apparatus, the combination, with the respective combustionchambers of the ovens B B, and gasheaters AA, and the hot-air main L, of the perforated air-cylinders O and blocks S within the combustion-chambers, and their connecting-pipes R T T, and N, having suitable valves, whereby a forced blast of hot air may be supplied to the respective combustion chambers of the ovens and heaters, substantially as and for the purpose specified.

10. In aregenerativchot-blast apparatus, the combination,with the ovens B B and the hotair main L, or parts in free communication with it, the perforated air cylinders O and blocks S within the combustion-chambers, and their connecting-pipesR and T provided with suitable valves, substantially as and for the purpose specified.

11. The herein-described rectangular ovens and gas-heaters, each divided into two parts, forming, respectively, combustion chambers and regenerators, the former being equal in length to the greatest width'ot' the ovens or heaters, and which ovens or gas -heaters are also divided into independent compartments, the regenerator portions of said compartments being provided with vertical flues arranged in sets, forming a decreasing series from the combustion-chambers to the cool end of the ovens or gas-heaters, whereby the products of combustion and blast or gas to be heated are evenly distributed, and the capacity of each set of flues and surface and materials are proportioned to the decreasing volume of the cooling and contracting products of combustion when the ovens or gas-heaters are being heated, and, conversely, when the ovens or gas-heaters are beating the blast or gas the capacity of each set of fines and surfaces and materials are proportioned to the increasing volume of the blast or gas as it becomes heated, thus producing a uniform velocity throughout the ovens or gasheaters in each case and very greatly increasing the efficiency of the apparatus, essentially as set forth.

12. The combustion chambers D of the ovens and gas-heaters, having the lower parts connected by the walls E and in which are placed, at theirangles, the perforated air-blocks S and at the same level the perforated central air-cylinders 0 substantially as described.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

JOHN 0. LONG.

Witnesses:

JAMES L. NoRRrs, J. A. RUTHERFORD.

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