US1647570A - Hot-blast stove - Google Patents

Description

Nov. 1, 1927. 1,647,570

. F. E. KUNG EGT BLAST STOYE Filed May 15, 1926 FEED E /Q /N Patented Nov. `1., 1927.

UNITED lSTATES FRED E. KLING, OF YOUNGSTOWN, OHIO.

Hor-BLAST srovn.

'application med nay 15,

This invention relates to hot blast stoves and more particularly to continuous hot blast stoves, and has for one of its objects-the' provision of a continuous hot` blast stove having a materially higher efficiency than hot blast stoves heretofore constructed.

f Another object is to provide a stove of the class described which will have a long life due toits novel construction.

. A further object is to provide a stove having novel means for permitting expansion of the parts due to the high temperatures.

A still further obj ect is to provide a stove having the novel construction, design and combination of parts hereinafter described and illustrated in the accompanyingldrawings.

In the drawings: y A C Figure 1 is a vertical section through a stove constructed in accordance with this inv vention. Figure 2 is a sectional plan of the stove. Figure 3 is a vertical section on the line III-III of Figure 1.

Referring more particularly to the drawings, the numeral 2 designates the stove as a whole, which is composedof a combustion chamber 3 and a heat exchanging chamber A gas or other fuel burner 5 is mounted 1n the end wall 5a of the stove and enters the 6 counter-current to the products of combuscombustion'chamber 3. The burner 5 is preferablyfa gas burner adapted to burn dry cleaned blast furnace gas. o l

The combustion chamber 3 opens into the heat exchanging chamber 4, which last namedv chamber is provided with a flue or stack opening 4a at the opposite end from the combustion chamber so that the products of combustion must flow through the heat exchanging chamber in order to pass to the stack.

A system of air blast pipes 6 are mounted in the heat exchanging chamber 4. `The pipes 6 enter the chamber 4 at its end farthest from the combustionl chamber 3 and are coiled upwardly and downwardly through the chamber 4 and exit through the opposite end of the heat exchanging chamber above the combustion chamber. The several coils of the pipes 6 are inclined slightly from the vertical so as to form supports for baile walls 7 which are arranged infront of each of the coils of pipe and rest on the pipe.

The inclination ofthe coils of pipes 6 is as slight as practical in order to support the baille walls and at the same time reduce the 192s. serial No. 109,452.

bending strains in the pipes to a minimum. 4An additional baffle wall 7 .is arranged under the exit end of the pipes 6 to prevent the products of combustion impinging di- .The cold `blast is adapted to enter the pipes 6 from a main 8 through a manifold 9 and toJiiow through said pipes counter-cur- 'rectly against the .pipes as they leave the combustion chamber. i

pipes may be four inches in diameter while the exit end will be six inches ormore in diameter, and the intermediate portion will of these sections will be preferably welded tothe preceding section so as to make a tight Joint.

By passing the blast air through the pipes tion passing through the chamber 4, the

' products of combustion contact with the portion of the pipes 6 containing the low temperature air, resulting in high efficiency of utilization of heat and consequently low consumption of gas or fuel.

The portion of the pipes 6 in the hot zone of the stove that is nearest the combustion chamber 3 is preferably made of a chrome steel alloy so as to withstand the high temperatures to which they are subjected without progressive oxidation, while the remainder of the pipes 6 located in the cooler zone of the'stove that is farthest from the combustion chamber 3 maybe composed of ordinary standard or commercial steel.

The pipes 6, due to the'temperatures to which they are subjected, will have considerable expansion.k Therefore, the coils of the pipes 6 are terminated short ofthe top wall of the chamber 4 so: as to permit them to eX- pand upwardly, `while the lower ends of the coils are supported or seated on the bottom wall of the chamber.

The upper ends of the coils of pipes 6 are y each provided with guide rods 14 which project upwardly into suitable recesses 15 1n the top wall of the stove to support the'upper ends of the coils and permit free expansion thereof.

The pipes 6 in the hot zone or nearest the` combustion chamber 3 will be subjected to the highest temperatures and will, therefore, have ,the greatest expansion, whereby the coils nearest they combustion chamber will tend to lift the adjoining coils from the bot-J tom wall of the stove while the coils nearest the' combustion chamber remain seated on the bottom wall. To compensate for this unequalv expansion, and to prevent undue load or stresses on the pipes due to the unequal expansion, the coils of the plpe's 6 1u the cooler zone` or farthest from the combustion chamber 3, are provided with plunger rods 16 which extend downwardly into a recess 17 and yare engaged by springs 18 which serve to normally force the cool pipe coils, and thereby prevent warping of the pipe coils due to unequal expansion.

The temperature of the air blast in stoves of this classl can be automatically controlled by standard thermostat gas control apparatus operable by the temperature of the hot blast and adapted to regulate the flow of gas to the burner 5. The thermostat mechanism is not shown, since any of the several standard thermostatically controlled regulators may be used.

The efficiency of a hot blast stove of this class is materially higher than stoves heretofore in use, since the temperaturel ofthel Awaste gases or products of combustion leaving the heat exchanging chamber can be kept at approximately five hundred degrees Fahrenheit, due to the waste gases being in contact with the pipes 6 carrying air at approximately two hundred degrees Fahrenheit prior to their exit to the stack. The efficiency of this stove will also be higher due to its materially decreased radiating surface over stoves heretofore in use.

The present stove will require considerably less labor due to it being capable of automatic control, and due to the fact the chimney and other valves are eliminated thereby reducing the parts liable to give trouble.

The present stove will not clog with dustsince the dust can be blown off the pipes 6 with soot-blowers during the operation of the stove, thereby permitting constant high eliiciency.

The above and many other advantages will be readily apparent to those skilled in the art.

While I have shown and described one specific embodiment of my invention, it will be understood that I do not wish to be limited thereto since various modiications may be made without departing from the scope of my invention as deined inthe appended claims. 4

I claim:

1. A continuous hot blast stove comprising a combustion chamber, and a heat .exchanging chamber through which the products of combustion pass from esaid combustion chamber, a plurality of metallic pipes coiled upwardly and downwardly through said 'heatexchanging chamber, the coils of said pipes being inclined slightly from the vertical, baffle walls along each of said coils of pipes, said baile Walls being alternately spaced from the bottom and top walls of said heat exchan ing chamber to cause the products of com ustion to travel along all of said pipes, means for permitting said coils of pipe to expand upwardly, and means for compensating for the greater expansion of the pipes closest to said combustion chamber over the pipes farthest from said combustion chamber.

2. A continuous hot blast stove comprising a combustion chamber, and a heat exchanging chamber through which the products of combustion pass from said combustion chamber, a plurality of metallic pipes coiled upwardly and downwardly through saidy heat exchanging chamber, the coils ,0f said pipes being inclined slightly from the vertical,baille walls along each of said coils of pipes, said baille walls being alternately spaced from the bottom and top walls .of said heat exchanging chamber to cause 'the products of combustion to travel along all of said pipes, and meansfor permitting said coils of pipe to expand upwardly. u

3. In a hot blast stove having a heat exchanging chamber,` a plurality of air blast pipes coiled upwardly and downwardly through said chamber, said coils of said pipes terminating short of the top wall of said chamber, and guide rods on the upper ends of said coils of pipe and mounted in recesses in the top wall of said chamber so as to support said coils and permit expansion of said pipe.`

4. In a hot blast stove having a heat exchanging chamber, a combustion chamber communicating with the heat exchanging chamber at one end thereof and a lue communicating with said heat exchanging cha-mber at the other end thereof so that the products of combustion will pass from said combustion chamber through said heat exchanging chamber from end to end thereof, a plurality of air blast pipes coiled upwardly and downwardly through said heat exchanging chamber, said coils of pipes terminating short of the 'top wall of said heat exchanging chamber, guide rods projecting from the upper ends of said coils of pipe and extending into recesses inthe top wall of said heat exchanging chamber, said coils of pipes adjacent said combustion chamber being adapted to have a greater expansion than the pipe coils farther from said combustion hembalance the weight of said cooler coils and ber dueto the greater heat of the products thereby compensate for the unequal expanof combustion whereby said coils of pipes sion and prevent breakage of said pipes. 10 having the least. expansion will be lifted In testimony whereof, I have hereunto 5 from their seats,v and spring supports for signed my naine.

supporting the lower ends of the coils of i pipes havlng the lesser expansion adapted to v FRED E. KLING.

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