US1789966A - Heating furnace - Google Patents

Description

Patented Jan. 27, 1931 UNITED STATES PATENT OFFICE I HEATING FURNACE Application-med January 8, 1929. Serial No. 331,015.

This invention relates to heating furnaces and method of firing said furnaces and, while not limited thereto, relates more particularly to heating furnaces particularly adapted for heating billets, sheet bars and the like, and to a novel method of firing said furnaces whereby the material being heated may be.

have substantially a uniform temperature at the exit or forward end of the combustion chamber. p

Another object is to provide a furnace of this class in which the maintenance cost Will be materially reduced since the flame is directed against the forward wall of the combustion chamber which is open and free to complete circulation of air.

A further object is'to provide a furnace having materially increased elliciency over furnaces of the prior art wherein the dame travel is in a single direction over the maw terial being heated.

In the drawings- Figure lis a longitudinal sectional view through a furnace constructed inV accordance with this invention andadapted to carryy out this novel method.

Figure 2 is a transverse sectional elevation taken on the line II--II ofFigure 1.

Referring more particularlyto the drawings, the numeral 2 designates the furnace' hearth which ris of the usual horizontal construction and is provided with skid members 3 and 3*. The skid member-s3 are water cooled while the skid members 3 are solid uncooled members.

A low enclosing structure 4 is provided over the hearth 2. from the rear or entering end forwardly for a material distance and forms a low channel portion or heating chamber 5. The rear end of the enclosing structure 4 is provided with an opening 6 through which the material to be heated isl charged into the furnace.

Forward of the enclosingportion 4 an enclosing portion 7 is provided which is built up a material distance above the portion 4 and extends forwardly to the forward or discharge end of the furnace and forms a combustion chamber 8. The ends vof the vchamber 8 are closed by rear and forward end Walls 9 and 10, respectively. The forward end wall 1() is provided with an opening 12 through which the heated material; is discharged.

A vertical flue 13 is provided at the rear end of the chamber 5 and ex .ends downward ly and connects with a horizontal flue 14 which extends forwardly under the furnace and delivers the products of combustion and heated gases to an suitable recuperator or regenerator (not shown) which is ada. ted

to supply preheated air to the burners o l thelivered thereto/from a main conduit 18 and `.branch conduits 19.

lt will be yunderstood that this invention vis not limitedto the 'use of gaseous or liquid .fuel burners in the-chamber 8, since any fuel .for underring vinthe ordinary manner so as to impinge'a flame against the underside of the'material being heated.

The operation 'of he` above described furnace' when carryin out the method of this invention is as fo ows:

Assuming that the furnace is charged and in operation, the flame from the burners 16 will be forced forwardl in a substantially horizontal plane throug the up er portion of the combustion chamber 8 until it strikes the forward wall 10 of the chamber, which wall will force the dame-body to turn downwardly toward the furnace hearth 2 and the flame will then be compelled to flow rearwardly in seeking an escape in a direction oppositely to that of the movement of the material being heated. This rearward iow or travel of the flame will be aided materially by the draft from the iues 13 and 14 and the fiame will thus be drawn the entire length of the furnace hearth. By causing a reverse flow of the flame-body so that the upper and lower portions thereof are {iowing in opposite directions,a vertical horse-shoe sha ed traveling flow-body of flame is provide in the combustion chamber 8 above the material being heated. The upper or forwardly traveling portion of the iow body of ame is the hottest and the lower 'or rearwardly traveling portion is the coolest. Therefore the coolest flame is in contact with the metal being heated while the hottest ame is separated by the cooler fiame from the metal and heats the metal by radiation only.

B-y providing this novel liow of the flame, the length of flow for a given length of combustion chamber is increased, the hottest ame is prevented from impinging directly on the metal, a more uniform temperature throughout the combustion chamber is had, and a soaking'condition is provided since the hottest a'me temperature is over the cool metal as it enters the combustion chamber,

' and both the gases and steel are substantially at a uniform temperature at the forward or dischar e end of the furnace.

Anot er feature resulting from the novel method of ring of this invention is that the wall l0 against which the flame im ,inges is free to have a complete circulation o air over its outer surface. Therefore said wall will have a materially increased life andymaintenance cost will be materially reduced over that resulting when the ame is directed against the rear wall, as is ordinarily the practice.

A stillfurther advantage resulting from the novel method of firing of this application is that the infiltration of cold air through the discharge port or opening 12 is substantially prevented due to the force of the flame at this point.

Many other advantages resultl from my novel method and will be apparent to those skilled in the art.

While T have shown and described one specie embodiment of my invention it will be understood that l do not wish to be limited thereto, since various modifications may be made without departing from the scope of my invention as defined in the appended claim.

I claim:

A continuous heating furnace for heating billets, sheet bars and the like, comprising top, bottom, side and end walls, said top wall'. being stepped upwardlyv from a point interi' mediate the ends of said furnace to one end wall to form a high' combustion chamber of more than one-third the total length of the. furnace, the end wall farthest from said high combustion chamber being provided with an. inlet port through which the material to be heated enters said furnace and the other end wall closing the forward end of said high combustion chamber being provided with an outlet port opening to the atmosphere through which the heated material is discharged, at least one fuel burner mounted lin the back wall of said high combustion chamber adjacent the top thereof and directing a flame against the forward end wall of said furnace, and a fiue connection adjacent the rear or entering end of said furnace, said fiue communicating with the interior of said furnace through the bottom wall thereof below the material being heated, said burner and said flueA being arranged to cause the flame after being projected toward the forward end wall of said furnace to reverse and flow back along said furnace under the flame body issuing from said burner and then continue rearwardly in contact with the material to be heated throughout the length of said furnace.

In testimony whereof, I have hereunto set my hand.

ALBERT L. CULBERTSON.

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