US1769366A - Open-hearth port design - Google Patents

Description

' y 1930- (5.1 DANFORTH, JR 1,759,356

OPEN HEAR'IH PORT DESIGN Filed Oct. 8, 1921 2 Sheets-Sheet 1 5 r I a! v y 1-930. G. L. DANFORTH, JR 1,769,366

'bPEN HEARTH PORT DESIGN Filed Oct. 8, 1921 2 Sheets-Sheet 2 ZZZ/672M Patented July 1, 1930 UNITED STATES PATENT OFFICE GEORGE L. DANFORTH, JR., OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO OPEN HEAR'IH COMBUSTION COMPANY, OF CHICAGO, ILLINOIS, A COR- PORATION OF DELAWARE Application filed October 8, 1921.

This invention relates to a new and im proved open hearth port design and more particularly to a design of this character adapted to provide a relatively restrlcted incoming port area and relatively large area for the products of combustion upon the outgoing end.

Open hearth furnaces, as is well known in the art, are double-ended and reversible, being provided upon each end with ports, these ports serving upon the incoming end to introduce air and fuel and upon the outgoing end to conduct away the products of combustion. The products of combustion considerably exceed in volume the incoming air and gas and, therefore, the port areas are largely designed with regard to the area necessary for carrying off the products of combustion. The port areas, in the usual type of furnace, are, therefore, greater than is necessary or desirable upon the incoming end. These large port areas render it difficult to secure an adequate mixtureof the air and fuel and also render it diflicult to properly control the flame.- In general, the air is. introduced upon either side and above the stream of gas or other fuel and the mixture of air and fuel takes place slowly as the elements pass across the furnace. This slow mixture gives a long flame which does not adequately act upon the portion of the bath adjacent the incoming end and which further wears away the port walls upon the outgoing end.

' It is highly desirable to secure a short, quick flame, and to secure such a flame, 1t is necessary that the air and fuel mix rapid- 1y upon the meeting of the fuel and air streams. This mixture can be accomplished by providing inwardly inclined portions of the furnace wall adapted to direct the incoming air at an angle toward the incoming gas stream. Such wall constructions, however, reduce the effective area for passage of the combined air and fuel stream, and consequently, upon the outgoing end, reduce the area for the products of combustion. This reduced area requires that an additional draft be provided in some man OPEN-HEARTH PORT DESIGN Serial No. 506,354.

ner to adequately take care of the prodnets of combustion.

Endeavors have been made to remedy this defect in regard to the outgoing end by provision of auxiliary passages for carrying off the products of combustion, these passages being closed upon the incoming end by water-cooled dampers. struction accomplishes the end sought, there are considerable heat losses due to the watercooled apparatus, and the addition of this apparatus and of its operating mechanism somewhat complicates the furnace.

It is an object of the present invention to provide an open hearth port construction in which the incoming air is directed toward the incoming gas, and the combined stream passed through a restricted opening to secure a quick mixture and short flame, and-in which auxiliary ports are provided forcarrying off the products of combustion from the outgoing end.

While such a con- It is a further object to so design the It is an additional object to so design the junction of the auxiliary exhaust ports and the air passages as to minimize any tendency for air to flow from the ports.

It is also an object to provide means located at the junction of the auxiliary ports and the air passages adapted to aid in carrying the incoming air pastthe auxiliary port opening.

Other and further objects will appear as the description proceeds.

Broadly, my invention comprises the formation of a restricted passage in front of the air and fuel ports whereby the air is directed into the fuel stream. It further provides additional exhaust passages leading from the melting chamber of the furnace to the air passages, preferably the air uptakes. The auxiliary passages are formed smaller at their point of junction with the air passages in order to minimize any air coming from the air passages into the auxilpassages to the iary ports, and preferably increase in size 7 Figure 1. These auxiliary ports preferably join with the air passages at a point below the air port level, and the brick work forming the lower portion of the auxiliary passage extends into the air passage to direct the air stream to pass the auxiliary port opening. Additional means for preventing incoming air from passing into the auxiliary ports are provided in the form of jets of compressed air forming an air curtain across the inner end of the auxiliary port. In the preferable form, these air jets carry with them a portion of the incoming pre-heated air which is by-passed from the main air passages.

I have illustrated certain preferred einbodiments of my invention in the accompanying drawings in which-4 Figure 1 is a longitudinal section of one end of an open hearth furnace constructed according to my design;

Figure 2 is a horizontal section of Figure 1 taken upon line 2-2; and

Figure 3 is a horizontal section of Figure 1 taken upon line 33.

Referring now to the drawings, the gas uptake 6 leads from the gas slag pocket 7 to the gas port 8, all of which are of usual construction. The air is led from air slag pocket 9 through the air uptakes 10, these uptakes joining above the gas port at 11. Air ports 12 are defined between gas port body 13 and the inwardly extending piers .14. These piers 14 together with thedownwardly inclined portion 15 of the roof serve to direct the incoming air angularly toward the incoming air stream both from the sides and from above. The restricted area defined by the roof and the inner ends of the piers 14 serves to aid in causing a quick mixture of the air and gas. Auxiliary ports 16 are provided which lead from the outer face of the piers 14 downwardly to the air uptakes 10. These ports 16, as best shown in Figure 1,- gradually decrease in cross-sectional area toward their point of junction with the air uptakes. The brick work 17 upon the lower face of the ports 16 extends into the air uptake 10 a greater distance than does the brick work upon the upper side of the ports 16. The air rising through the uptake is thus directed past the opening of the ports 16 into the uptake.- i

A slit 18 is provided extending transverse- 1y across the ports 16 substantially in line wlth the upper face of the port wall at its point of junction with theair uptake. This slit is provided with water-cooling means 19 to preserve its shape and .area. Located below this slit is a pipe 20 provided with nozzles 21 and connected to any suitable source of compressed air. The slit 18 increases in area downwardly and its lower end 22 opens into the air uptake 10 adjacent the air slag pocket, The compressed air passing through slag pocket 7, uptake 6 and out through the port 8. The main body of incoming air passes through the slag pocket 9 and through the air uptakes 10 and joining at 11 forms a blanket of air enclosing the gas stream upon its sides and above. A relatively small amount of compressed air is introduced through the pipes 20 andnozzles 21 and serves to carry with it a-small amount of the incoming pre-heated air through the bypass openings 22 and up through the slits 18. The brick work 17, the smaller area of the inner end of the port 16, and its location intermediate the length of the uptake also serve to minimize any flow of incoming air through the ports I 16. The relative volume of compressed air is so small as to have but little cooling effect upon the whole volume of incoming air.

Upon the outgoing end, the products of combustion pass through the auxiliary ports 16 and also to some extent through the air ports 12to the air uptakes 10 down which they pass to the air slag pocket 9 and to suitable regenerative chambers which have not been shown as they are well known in the art. A portion also of the exhaust gases passes through the gas port 8 and down through the gas uptake 6 to the gas slag pocket 7 and thence through the gas regenerators.

I have shown a number of methods combined to minimize the flow of the incoming air through the auxiliary ports, and any or all of them may be used. My invention is susceptible of many modifications and changes to meet varying conditions and it is my intention to cover all such changes as come within the spirit and scope of the appended claims.

I claim:

1. In an open hearth furnace, air and gas uptakes leading to air and gas ports at each end of the furnace, discharge passages for the products of combustion connecting the melting-chamber and air uptakes, and means adapted to prevent flow of air through said dischar epassages upon the incoming end of the urnace.

2. In an open hearth furnace, air and fuel ports and passages in the furnace ends, in-

wardly inclined piers in the furnace defining a relatively restricted passage between the ports and melting chamber and auxiliary discharge ports extending through said piers, and leading to the air-passages.

3. In an open hearth furnace, air and fuel ports in the furnace ends, inwardly inclined piers in the furnace defining a relatively reed passage between the ports and melting chamber and auxiliary discharge ports extending through said piers, and leading to the air uptakes below the air ports.

5. In an open hearth furnace, air and fuel ports and passages in the furnace ends, piers in the furnace defining a relatively restricted passage between the orts and melting chamber and auxiliary discharge ports extending through said piers, and leading to the air passages, said passages decreasing in size from the melting chamber.

6. In an open hearth furnace, air and gas uptakes leading to air and gas ports at each end. of the furnace, and discharge passages for the products of combustion connecting the melting chamber and air uptakes, said passages decreasing in size from the melting chamber.

7 In an open hearth furnace, air and fuel ports and passages in the furnaceends, and auxiliary discharge ports connecting the melting chamber and air passages, said ports decreasing in size'from the melting chamber toward their junction with theair passages.

8. In an open hearth furnace, air and fuel ports and passages in the furnace ends, and

auxiliary discharge ports connecting the melting chamber and air passages, the lower wall of the auxiliary ports extending into the air passages whereby air coming in through the passages is deflected past the opening of the auxiliary port.

9. In an open hearth furnace, air and fuel ports and passages in the furnace ends, and auxiliary discharge ports connecting the melting .chamber and air passages, and means adapted to produce a curtain of air across the opening of said auxiliary ports from the air passages to prevent flow of air through said auxiliary ports on the incoming end of the furnace.

10. In an open hearth furnace, air and fuel ports and passages in the furnace ends, and auxiliary discharge ports connecting the melting chamber and air passages, and means adapted to byrpass a portion of the incoming air across the opening of said auxihary ports from the air passages, said air forming a curtain to prevent flow of air through said ports on the incoming end of the furnace.

11. In an open hearth furnace, air and fuel ports and passages in the furnace ends, and auxiliary discharge ports. connecting the melting chamber and air passages, and means including a by-pass passage terminating in a slit across the lower face of the auxiliary port, adapted to by-pass a portion of the incoming air across the opening of said auxiliary ports from the air passa es, said air forming a curtain to prevent ow of air through said ports on the incoming end of the furnace.

12. In an open hearth furnace, air and fuel ports and passages in the furnace ends, and auxiliary discharge ports connecting the melting chamber and air passages, and means including a by-pass passage terminating in a slit across the lower face of the auxiliary port, and compressed air nozzles adapted to induce flow of air through said by-pass and slit adapted to by-pass a portion of the incoming air across the opening said air forming a curtain to prevent ow of air through said ports on the incoming end of the furnace.

13. In an open hearth furnace having small port area for the incoming air and gas and additional port area for the outgo ingproducts of combustion, and connecting passages associated with said ports, compressed fluid means operating in said passages whereby the flow of incoming air is controlled and directed to said small port area.

fuel ports and passages,-a passage opening from the air passage, and means adapted to discharge compressed fluid whereby a flow of air through said passage from the air passage is induced.

15. In an open hearth furnace, air and fuel ports and uptakes, a passage opening from the air uptake, and means adapted to' discharge compressed fluid whereby a flow of air through said passage from the air uptake is induced.

16..In an open hearth furnace, air and fuel ports, air uptakes, passages leading from said uptakes and nozzles adapted to of September, 1921.

GEORGE L. DANFORTH, J R.

14. In an open hearth furnace, air and

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