US2288491A - Open hearth furnace - Google Patents

Description

June 30, G. E. sElL 2,288,491

OPEN HEARTH FURNAGE June 30, 1942.

G. E. SEIL OPEN EARTH FURNACE Filed nec. 14, 1940 5 Sheets-Sheet 2 June 30, 1942. G. E. sElL 2288.491

OPEN HEARTH FURNACE Filed neg. 14. 1940,. s sheets-sheer s Patented June 30, 1942 UNITED STATES PATENT OFFICE OPEN nEAR'rn FURNACE Gilbert E. Seil, Cynwyd, Pa.

'Application December 14, 1949, serial No. 370,203

2 Claims. (C1. 263-15) f `This invention relates to regenerative and recuperative furnaces and, more particularly, to open hearth furnaces;

An important Iobject of the invention is the provision of an open hearth furnace construction wherein a maximum heat transfer may be obtained without such dispersion of the flame as will result in destruction of the furnace walls.

Another object of the invention is the provision of a means whereby the type of flame employed in the furnace may be very readily regulated.

Still another` object of the invention is the provision of a construction whereby an increased B. t. u. release may be effected in a given area and wherein the release will be comparatively rapid as respects the usual open hearth construction.

Another object of the invention is the provision of a construction whereby the B. t. u. release during combustion will occur closely adjacent to the final bath level thus insuring preheating of the superimposed portions when melting down a cold ora mixed charge.

A still further and important object of the invention is to provide a construction such that a constant volume of fuel may be delivered to the furnace under all circumstances and the concentration of this content may be varied as desired.

A still further Object of the invention is the provision of a construction enabling attainment of the above objects without the necessity of alternating the fuel flow between two burners supplying the furnace as in the usual construction.

'I'hese and other objects I attain by the con.- struction shown inthe accompanying drawings wherein, for the purpose of illustration, I have shown a preferred embodiment of my invention and wherein:

Fig. l is a diagrammatic vertical sectional view of an openhearth furnace constructed in acf cordance with my invention;

Fig. 2 is a vertical sectional view through the furnace; Y

Fig. 3 is a section on line 3-3 of Fig. 2;

' Fig. 4 is a diagrammatic view showing the fuel and air supply means employed with the burner system; and f Fig. 5 is adetailed longitudinal sectional view throughI 'a burner head.

Referring now more particularly to the drawings, the numeral I0 generally designates the hearth chamber of an open hearth furnace, and I I, a pair of checkers connected with the hearth by downtake flues I2. By means of a butterfly valve I3 the checkers I I are selectively and alternately connectable with a stack I4 and an air intake I5. As described, the mechanism is identical with that ordinarily employed in an open hearth furnace.

In accordance with my invention, checkers II are connected by ducts I6 through a blower I1 with a manifold I8. Hearth chamber III is equipped with a plurality of'burners I9 which Amay be of any desired number and are directed through opposite side walls v20 of the hearth chamber. The burners at either side of the hearth are staggered with relation to those of the opposite wall in their spacing longitudinally of` the hearth and havetheir inner ends disposed at or slightly above the bath level of the hearth. Burners I9 are of the type shown in my prior Patent No. 2,137,185, granted November 15, 1938, for Multiple burner arrangement, and each 4comprises a burner head 2I having a central fuel tube 22 and an annularchamber 23 surrounding this tube and supplying oxygen either throughthe medium of compressed air or steam `operated from a constant speed motor 28 through an infinitely variable transmission 29 such as that known as theReeves drive. 'I'he pump 21 has its sole discharge to the burners I9 with the result that the quantity of fuel measured by pump 21 and delivered to the burner System will be discharged into the furnace without regard as speed motor, thus serving as a vmeans for conto whether one or more of the burners becomes clogged. y 4

The lmotor 30 operating blower I1 is a variable trolling the amount` of secondary air delivered to the chamber I0 through the manifoldvl. The structure obviously lends itself to automatic control. f

Burners I9, as hereinbefore noted, have their inner ends located immediately above the bath level in the hearth and are disposed at a slight angle to the horizontal. yI have found that this angle should be below 22 to the horizontal since, otherwise, thereis mushrooming of the flame against the charge throwing the flame tips back against the wall of the furnace and tending to Vangle be approximately 15, although. it may be made lower thanlihis'withoutl any noticeable 'change in operation as long as the burner llrept above 3 .to the horizontal. l

It'will be obvious that in a construction of this A, character there is no necessity for periodical reversal of the' fuel 'supply as is necessary in the -asingle. long flame lresults in a high concentra- .most work. Since the concentration of the name Theconstruction illustrated is, furthermore,

highly advantageous in thatt enables ready con-- trol of the .B. t. u. concentration. It will `be noted that if the air supplied through the manifold lla is insufficient to supply the needs of burners I9 the down-take nue of the active checker will Supply additional air to the hearth l chamber to meet the demands of stack i4, thereby resulting in a dispersion of the names; of the i individual burner tips to an extent-proportionate. to the supplies delivered from the manifold and the flue Iz. v regulation of the-A furnace conditions.

Obviously, this will permit a close I am aware that it heretofore prothe hearth chamber. with which I am familiar, however, the birner names directed 'against the charge from above and at a very high angle with the result that the flame mushrooms" against the charge and isrcected against the furnace walls to rapidly destroy the same. As a matter of fact,

1 `tests with such furnaces indicate that they cannot be practically operated with any of the present-day-refractories. .Furthermore with such ordinary Open hearth construction. The use of a multiplicity of small burner flames instead of ltion ofthe B. t. u, content ofthe combustible .mixture inthe area where itcan accomplish the y A :3,288,491 destroy the same. It is preferred in practice that constructions the molten metal has to flow downwardly over the unmelted charge in the furnace and there is no actual bath formed until the entire charge has been heated to the melting point. In my furnace, all of these objectionable characteristics are eliminated.

While I have illustrated andl 4described my invention as specifically applied to a` regenerative furnace, it will be obvious that the same prin-y ciple of lconstruction-and operation may, likewise, be applied to recuperative furnaces.

Since the construction illustrated is essentially diagrammatic and capable of considerable modification without in any manner departing from thev spirit of my invention, I do not wish to be understood as'limiting' myself thereto ex- 4 cept as hereinafter claimed.

I claim:

1. lIn a regenerative furnace, a furnace chamber, a pair of regenerators communicating therewith, aplurality of continuously operating burners directed through opposed walls of the fur- 'nace chamber and against a charge contained therein, the burners ofeach wall being staggered with ,relation to those of vthe opposite wall, a

manifold to supply air to said burners, a stack', -means to alternately connect said regenerators ',posed vto employ a plurality of burners discharging simultaneouslyand continuously into In all such constructions to said stack, and means to selectively and alter- -nately connect said regenerators to said manifold said furnace, a plurality of continuously operating burners directed through opposed walls of the furnace chamber and-against a charge contained therein, the burners of each wall being staggered with relation to those of the opposite wall, a manifold to supply air to said burners,

ducts connecting said manifold and said re generators, a stack, means to alternately connect said regenerators to said stack and toa source of air, and means to selectively and alternately connect said lregenerators. through the last-named ducts to said manifold.

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2. In a regenerative furnace, a furnace chax'n-y v ber, a pair of regenen-stars. a continuously open duct connectingeach of said regenerators and

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