US1769494A - Open-hearth furnace - Google Patents

Description

July 1, 1930. G. L. DANFORTA. JR 1,769,494

OPEN HEARTH FURNACE 'Original Filed Sept. 26, 1921 4 Sheets-Sheet 1 July 1, 1930. G. L, DANFORTH, JR 1,769,494

OPEN HEARTH FURNACE l original Filed sept. 2e, 1921 4 sheets-sheet 2 Jly l, 1930. G. l| DANFORTH, JR

OPEN HEARTH FURNACE original Filed sept. 2e, 1921 4 Shee'ts-Sheet 3 eoffge LmfO/"Z/Z JK,

July 1, 1930. G. L. DANFORTH, JR 1,769,494

" OPEN HEARTH FURNACE original Filed sept. 2s, 1921 4 sheets-sheet 4 Patented July4 l, 1930 UNITED STATES PATENT OFFICE GEORGE L. DANFORTH., JR., OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIIGN- HENTS, TO OPEN HEARTH COMBUSTION COMPANY, OF CHICAGO, ILLINOIS, A.

CORPORATION OF DELAWARE OPEN-Emma rUnNAcE I Original application filed September 28, 1921, Serial No. 503,241. Divided and this application led y A April 4, 1930. Serial No. 441,542.

This inventionrelates to a new and improved open hearth furnace, and more particularly to a construction adapted to so direct the entering gases and air in an open hearth furnace as to produce a quick burning and intensely hot llame adapted to provide Working heat adjacent the full surface of the metal inthe furnace, and further adapted to provide a' large' port area through which to exhaust the products of combustion.

'This application is a division of my copendin application Serial No. 503,241, filed Septemel" 26, 1921.

My invention comprises an improvement in that portion of-an open hearth furnace be- -tween the ports and the bath or melting chamber, and the remainder of the furnace and its appurtenances may be of any usual constructiom 'As is well known in open hearth practice, the furnace is double-ended a'nd reversible, and is provided at each end with gas or air ports' which serve upon the outgolng endto carry `off the products of combustion. In certain types of these fur-y naces burning producer or like gases, these incoming gases are passed through regenerative chambers and are thus pre-heated. The incoming air is pre-heated in .a similar manner and the heat of the furnacev flame is correspondingly increased. It is highly desirable in such furnaces to provide a short, quick llame which is directed toward the metal in the bath and which does not extend to the outgoing end of the furnace. However, in actual practice, since the same portsserve both to introduce the air and gas and to carry oi' the products of combustion, the latter function has been largely the determining factor as regards the size of ports. This is for the reason that the products of combustion are of considerably greater volumethan the incoming air and gas.

To secure a short, nick flame, it is essential that there be a ,quick and thorough mix,- ture of the incoming air and gas. It is impractical to secure such a mixture and liame when the air and gas ports are of the usual comparatively large area. Endeavors are made to secure this quick mixture with such ports by surrounding the gas stream upon its sides and top with the air stream. However, theintermixture in general occurs gradually as the gas is passed across the furnace, the lighter glas gradually rising and intermingling wit the heavy air, combustion thus gradually taking place.

Endeavors have been made to secure a quick mixture and short llame by means of using comparatit'ely smalllair and -gas ports and providing auxiliary orts for carrying 'oil' the products of com ustion. ln such constructions, dampersgare provided to close the auxiliary passages u on the incomin end of the furliacejjg.V The Iaddition of auxilg iary ports and up es unduly complicates the structure and this is particularly true in the usual type of furnace burning producer or similar gases. In such furnaces ,-as generallyconstructed, a single gas'uptake and port is flanked by anv air uptake and port upon each side thereof. All these ports are essential'tothe operation of' a furnace upon the `incoming end, although as has been stated, the port area is increased'over that necessary for the incoming air Aand gas in order to be of a size adequate 'to take care of the productsof combustion.

It is an object of the present invention to provide means located intermediate the ports and the furnace chamber which means are adapted to vary the edective passage area between the vports and chamber.

It is a further object to provide means of this character which are adjustable to provide the full port area for handling the prod'- ucts ofcombustion. A

It is an additional object to provide means which may be readil lnstalledwithout undue modificationv `'0 the existing furnace structure.

It is also an object to provide a device which is relatively 'simple in design, construction and operation.

Other and further objects will appear as the description proceeds.

Broadly my invention cbmprises the interposition of dampers between the ports and furnace chamber, these dampers being adjustable-,to vary the effective passage area. I have illustrated certain preferred embodishowing a portion of the furnace roof piv-` ments of my invention in the accompanying drawings, in which- Figure 1 is a fragmentary, longitudinal section of an open hearth furnace having one form of my invention applied thereto;

Figure 2 is a horizontal section of the form shown in Figure 1;

Figure 3 is a view similar to Figure 1 but showing a form of device having a single, di agonally movable damper;

Figure 4 is a horizontal section of the form shownin Figure 3;

Figure 5 is a View similar to Figure 1 but showing a form of the device having a sin,- gle, arcuately movable damper;

Figure 6 is a horizontal section of the form shown in Figure 5;

Figure 7 is a view similar to Figure 1 but oted to act as a damper; and

Figure 8 is a horizontal section of the form shown in Figure 7.

In the form of construction shown in Figures 1 and 2, the gas-uptake 40 terminates in a relatively wide gas port 41.A The air uptakes 42 joinat 48 above the gas port and the effective air port is located entirely above the gas port. In this form, the single damper 44 is passed through water-cooled guideways 45 in the roof. The damper is handled by means of the cable 46. Upon the outgoing end, it will be completely drawn up into the roof and upon the incoming end, it will be lowered suiiciently to properly limit the incoming p ort area and to direct the air stream into the gas stream. Y

In thegform of construction shown in Figures 3 and 4, the central gas uptake 51 leads to the gas port 52. The llateral air uptakes 53 discharge upon either side of the gas uptake. The furnace walls are deflected inwardly somewhat at 54 and thus direct the air streams laterally toward the gas. stream.

` This formation of the wall, however, is not suicient to obstruct the outgoing gases. The sliding damper 55 is carried in the inclined water-cooled guideways 56 and is handled by cable 57. In its upper position, the damper is housed in the box 58. A flange 59 upon the damper interlits with a flange 60 upon the box to preventpassage of gases into the box when the damper is lowered. This damper when-.lowered limits the passage area and forces thenixture of the air and gas due to this. restrictionin area. On the outgoing end, it israisedand permits the full area of the ports to be effective for carrying off the products of combustion.

The form of device shown in Figures 5 and 6 is quite similar to that of Fi es 3 and 4,

- the modification being that t e damper is arcuate in form and is rotated instead of sliding in guideways. This arcuate damper 61 is carried by the frame 62 which latter is rotatable about the shaft 63. Rotation of the frame about this shaft serves to swing the damper upwardly out of the furnace and into the box 64. Flanges 65 on the damper frame interfit with flanges66 upon the lower part of the box to preventthe passage of gases into the box when the damper is down. In the form of device shown 1n Figures 7 and 8 the gas uptake 71 is flanked bythe air 'i forward part of the damper vis provided with an upwardly extending flange 76 which serves to prevent the passage of gases between the forward edge of the damper and the roof when the damper is in lowered position.

These several forms of construction which I have shown all serve to restrict the effective passage area between the ports and the fur nace upon the incoming end of the furnace. They thus cause a quick mingling of air and gas and a short flame upon the incoming end and further permit the ready discharge of the products of combustion through the full port area. Other and further modifications Y uptakes 7 2. A portion of the furnace roof' i aov of my construction may be made and it is my intention to cover all variations coming within the spirit and. scope of the appended claims.

I claim:

l. In an open hearth furnace, a hearth having its-end walls at each end sloping towards each other to a port of lesser Width and height than the cross sectional dimensions of the hearth, a chamber behind each port of greater width than the width of the port, and having its walls sloping towards the port, suitable connections for the delivery of air and fuel behind each port, whereby as said air and fuel travel towards the port their velocity is increased with correspond ing improvement of mixture, a vertically movable damper in the upper portion of each port serving vto close said upper portion, and means for adusting each damper vertically under the control of the operator, substantially as described.

2. In an open hearth furnace, a hea'th havingl its end walls at each end sloping towards each other to a port of lesser width than the cross sectional dimensions of the hearth, a. chamber behind each port of greater width than the Width of the port, suitable and fuel for combustion through each port, l

trol of the operator, substantially as described.

3. In an open hearth furnace, a hearth, a port at each end of the hearth of smaller size than the cross sectional dimensions of the hearth, a chamber behind each port of greater width than the Width of the port, suitable connections for the delivery of air and fuel behind each port whereby as said air and fuel travel towards the port their velocity is increased with corresponding improvement of mixture, a vertically movable damper in the upper portion of each port serving to close said upper portion, and means for adjusting each damper vertically under the control of the operator, substantially as described.

4. In an open hearth furnace, a hearth, a port at each end thereof, a chamber behind each port having its roof sloping downwardly towards the port, means for delivering air a vertically movable damper 1n the upper portion of each port serving to close said upper portion, and means for adjusting each damper vertically under the control of the operator whereby the fiame emerging from each port is compelled to pass beneath the damper thereof, and whereby the operation of said llame may beadjusted by an adjustment .of the damper, substantially as described.

5. In an open hearth furnace, a hearth, a port at each end thereof, a chamber behind each port, means for delivering air and fuel for combustion through each port, avertically movable damper in the upper portion of each port serving to close said upper portion, and means for adjusting each damper vertically under the control of the operator whereby the flame emerging from each port is compelled to pass beneath the damper thereof, and whereby the operation of said flame may be adjusted by an adjustment of the damper, substantially as described.

6. In an open hearth furnace, a hearth, a port at each end thereof, a chamber behind each port, means for delivering air and fuel for combustion through each port, a damper for each port, and means for adjusting each damper under the control of the operator, substantially as described.

7. In an open hearth furnace, a hearth, a port at each end thereof, a chamber behind each port, and a vertically adjustable damper workingdownwardly with respect to each port, the roof of each chamber slo ing down towards its port at an angle of su stantially 30 to the horizontal, substantially as described.

8. An end construction for a regenerative open hearth furnace having a throat leading into the combustion chamber through which fuel may be introduced or products of combustion may escape, and means for varying the effective area of the throat including a damper extending transversely of the throat from one side wall to the other and movable into or out of the throat through an aperture in the furnace roof.

Signed at Chicago, Illinois, this 1st day of April, 1930.

GEORGE L. DANFORTH, JR.

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