US3336965A

US3336965A - Burner for blast stoves

Info

Publication number: US3336965A
Application number: US432109A
Authority: US
Inventors: Donald P Mckinnon; Olexen Steve
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1965-02-12
Filing date: 1965-02-12
Publication date: 1967-08-22
Anticipated expiration: 1984-08-22

Description

Aug. 22, 1967 D. P. M KINNON ETAL BURNER FOR BLAST-STOVES Filed Feb. 12, 1965 FIG: 1.

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DONALD .P. McK/NNO/V and STEVE OLEXEN Attorney United States Patent 3,336,965 BURNER FOR BLAST STOVES Donald P. McKinnon and Steve Olexen, Lorain, Ohio,

assignors to United States Steel Corporation, a corporation of Delaware Filed Feb. 12, 1965, Ser. No. 432,109 2 Claims. (Cl. 158-109) This invention relates to an apparatus for heating stoves. More particularly, the invention is directed to a burner particularly useful in conjunction with blast furnace stoves. Common blast furnace stoves comprise a combustion chamber to which is attached a gas burner which supplies gas (fuel) and air into the combustion chamber where the fuel is burned. Such stoves operate cyclically, alternating between combustion and air intake, the purpose of the stove being to heat incoming air by passing it through the stove after the stove has been heated.

Stoves of the type described above are generally heated by a burner extending through a burner port into the stove. The burner supplies a mixture of combustion gas and air which is ignited, sending a flame into the stove. Typically, such burners extend through the port into the stove and are, therefore, subjected to extreme conditions of heat which require them to be constructed of expensive materials capable of withstanding the high temperature to which they are exposed. In spite of expensive construction, however, burners which extend into the stove must be frequently replaced.

The present invention provides a burner which can be positioned entirely outside of the stove but which still provides effective and eificient heating through the burner port to the interior of the stove. The improved burner, according to the invention, comprises tubular combustion-air supply means which extends toward the burner port of the stove. Combustion gas is supplied through independent means into the interior of the combustion-gas supply means by an arrangement which is essentially a tube within a tube terminating near the entrance of the burner port. An air and gas mixer which enables the burner to be positioned outside the stove is fixed at the terminal end of the combustiongas supply means in front of the burner port and within the combustion-air supply means. The mixer comprises air-flow directing means symmetrically distributed about the perimeter of the combustion-gas supply means and within the combustion-air supply means. The air-flow directing means directs a portion of supplied combustion air in a converging direction into the burner port. The mixer also comprises means at the mouth of the combustion-gas supply means for directing a portion of supplied combustion gas in a diverging flow into the burner port. In this way, efiicient mixing of combustion air and combustion gas is achieved within the burner port and when ignited, provides effective heating for the stove interior.

Further details and advantages of the invention will become apparent from the following description of the accompanying drawings which illustrate a preferred embodiment of the invention. In the drawings:

FIGURE 1 is a fragmentary side elevation view of the of the burner and its adaptation with the burner port of a hot blast stove; and

FIGURE 2 is an enlarged partial side view of the burner taken along lines IIII of FIGURE 1 showing the air and gas mixer of the burner.

As is seen in FIGURE 1, the side wall of a hot blast stove contains a burner port 12 used for supplying heat to the stove interior. A suitable valve 8 is located at the burner port and is adapted to seal the burner port when the stove is receiving cold air for preheating in the stove chamber. Any suitable valve such as the gate type shown in FIGURE 1 may be used for this purpose. Positioned outside of the burner port but, advantageously, sealed thereto, is our improved burner 20. The burner can be easily attached to the gate valve 8 or directly to the side wall of the stove by means of a flange 6 as shown.

The burner itself, 20, comprises combustion-air supply means 22 which is a tubular section extending toward the burner port and which receives combustion air from a fan or blower ply of air. The burner may be conveniently supported on a stand made from steel plates and angles as shown.

Combustion gas is supplied through a tubular conduit 24 which delivers the gas into the combustion-air supply means 22 through a tubular section having a terminal portion 25 substantially parallel with the tubular combustionair supply means and having a common centerline with each other and with the burnerport 12 of the hot blast stove 10. The mouth or terminal opening 26 of the combustion-gas supply means terminates near the entrance of or in front of the burner port 12. Suitable means are provided to control the flow of combustion gas such as the butterfly valve 23 shown in the drawing.

An air and gas mixer is fixedly positioned at the mouth 26 of the combustion-gas supply means. The mixer comprises means 30 symmetrically distributed about the outer perimeter of the mouth 26 (best shown in FIGURE 2) for directing a portion, but not all, of supplied combustion air in a converging direction into the burner port. The mixer itself is preferably constructed as shown in FIGURES 1 and 2 with ribs 32 attached to the mouth 26 of the combustion-gas supply means and to which tubular sections 30 are also attached. In the embodiment illustrated, four symmetrically arranged tubular sections inclined toward the centerline of the burner port 12 direct a portion but not all of supplied combustion air in a converging direction. Conical section 34 is positioned at the center of the mouth 26 of combustion-gas supply means so as to direct a portion, but not all, of the supplied combustion gas in a converging direction into the burner port 12. Ribs 32 are attached at one end to the conical section 34 and to tubular sections 30 and at their other end to mouth 26, as discussed above. As can be seen, a portion of combustion gas and combustion air are directed by the mixer into intersecting paths producing a degree of turbulence which insures effective mixing of the combustion air and combustion gas. The ribs 32 may be secured to the tubular sections 30 and the conical section 34 by welding and can also be welded to the mouth 26 of the combustion-gas supply means.

It is important that the air-flow directing means employed in the mixer be symmetrically distributed about the combustion-gas supply means to insure: uniform mixing. Although four sections of tubular configuration are shown in the drawings, other arrangements of different configurations may be employed Which direct a portion of the combustion gas in a converging path symmetrically around the combustion-gas supply means.

It will be appreciated that the burner described herein avoids many of the safety hazards associated with conventional stove burners. For example, when not in operation, the burner is fully vented to the atmosphere through the fan and blower housing assembly. Moreover, only air is present in the outer cavity of the burner and there is little possibility of gas leakage into the surrounding atmosphere. The air and fuel mixer is positioned immediately adjacent the stove and the combustion gas and air is mixed in the burner port thereby avoiding combustion in the burner and permitting the burner itself to remain cool in operation. In this latter connection, it should be noted that the air and gas mixer is located ahead of the gas valve so that when the stove is being heated, the flow 18 adapted to provide a controlled supof gas cools the mixer and when the burner is turned 01f, the burner port gate valve is closed and the mixer is not exposed to the radiant heat from the combustion chamber. Because the burner is not exposed to extreme temperature conditions, it may be constructed of low-cost carbon steels and will last indefinitely. In the preferred embodiment, the burner is constructed of round tubes providing a laminar gas flow which also results in an economy of metal and reduction in welding as compared with other burners of rectangular design. The cylindrical surfaces of the burner eliminate pockets which would be otherwise difiicult to clean.

While one embodiment of our invention has been shown and described, it will be apparent that other adaptations and modifications may be made wtihout departing from the scope of the following claims.

We claim:

1. In a hot blast stove having a burner port through which a burner supplies a flame of combustible gas, the improvement comprising a burner positioned entirely outside said port adjacent said stove and sealably attached thereto, said burner comprising tubular combustion-air supply means extending toward said burner port, tubular combustion-gas supply means extending into said combustion-air supply means, said combustion-gas supply means having a mouth terminating in front of said burner port, an

air and gas mixer fixedly mounted at the mouth of said combustion-gas supply means, air-flow directing means symmetrically distributed about the outer perimeter of said mouth of said combustion-gas supply means and within said combustion-air supply means for directing a portion of supplied combustion air in a converging direction into said burner port, means positioned at the mouth of said combustion-gas supply means for directing a portion of supplied combustion gas in a diverging flow into said burner port, whereby efficient mixing of combustion air and combustion gas is achieved within the burner port.

2. The improvement according to claim 1 wherein the combustion-air supply means and the terminal portion of the combustion-gas supply means are substantially parallel tubular sections having a common centerline with each other and with the burner port of said hot blast stove.

References Cited UNITED STATES PATENTS 938,182 10/1909 Todd et al 158109 1,962,113 6/1934 Elmore. 2,269,699 1/1942 Stoecker et al 158109 3,195,872 7/1965 Schneider et al. 158109 X 3,217,781 11/1965 Curtis et al 158109 JAMES W. WESTHAVER, Primary Examiner.