US2578121A - Flame divergence controlling means for fuel oil burners - Google Patents

Description

Dec. 11, 1951 E T. w. BAILEY 2,578,121

FLAME DIVERGENCE CONTROLLING MEANS FOR FUEL OIL BURNERS Filed June 14, 1948 Patented Dec. 11, 1951 FLAME DIVERGENCE CONTROLLING MEANS FOR FUEL' OIL BURNERS Edward Thomas Walter Bailey, Hamilton, Ontario, Canada Application June 14', 1948, Serial No. 32,895 In Canada April 6, 1948 Claims. (01. 299-117) The invention relates to a fuel oil burner for use in open hearth furnaces.

It is well known that in the treatment of scrap iron and steel in open hearth furnaces a very hot sharp flame is required for heating up and melting the scrap but during the refining period the flame should be long and luminous so that the bath is heated by radiation from the glowing particles of carbon. The common practice is to introduce heavy fuel oil into the furnace through a burner, the oil being atomized and velocity imparted to it by steam, blast furnace gas or the like, admitted with the oil in a ratio of approximately 120 cubic feet of steam to one imperial gallon of oil. The air required for combustion is so introduced that the air which is entrained and the oil and steam flow along I parallel lines and produce a flame which diverges only slightly. The length of the flame depends on the heat of the furnace, the amount of air entrained and the proportion of steam to oil, the length being increased by cutting down the air and steam and thereby delaying combustion and reducing entrainment. When a hot sharp flame is required, as in heating and melting scrap iron and steel, the volume o-fair and steam is increased and when the melting is complete and a long luminous flame is required for the refining period, the air and steam are cut down.

The use of steam, blast furnace gas and the like, rather than compressed air in order to carry the oil into the furnace with sufficient velocity has the advantage that the steam tends to keep the air, which is required for combustion, away from the oil thereby delaying combustion and making it possible to extend the flame over the length of the furnace during the refining period. This action of the steam or blast furnace gas is actually a hindrance, however, during the heating and melting period when rapid combustion providing a short sharp flame is desired, and it has been recognized that a spreading or divergence of the oil leaving the burner would bring more oil particles into contact with the air sooner and thereby speed up combustion. Accordingly, devices have been proposed for causing the oil to spread out, but, since they involve interfering with the long luminous flame required in refining, little interest has been shown in such devices. In any event there has been a good deal of hesitation about using them because they may so easily result in the flame striking the sidewalls of the furnace and damaging them. It is, of course, possible to so construct a device producing divergence that, for a given set of conditions, the flame will not strike the walls. It is obvious, however, that such a device would only be satisfactory so long as the conditions were maintained the same because if, for example, the

volume of air admitted were changed, the result might well be to widen the diverging flame and cause it to break down the furnace walls.

As mentioned above, the flame required during the refining period is a long luminous flame which involves the parallel flow of air, oil and steam. It follows that for the refining period anything producing divergence should be eliminated. In most normal burners the mixing of the steam and the oil brings about a degree of turbulence which can cause a considerable amount of divergence which, though not extensive enough to be fully effective during the heating and melting period, is undesirable in the refining period.

According to the invention described in United States application Serial No. 769,964, new United States Patent No. 2,446,511 granted August 3, 1948, of the present applicant and F. G. Kerry entitled Open Hearth Steel Making, combustion is accelerated during the heating and melting periods by intimately bringing together oxygen in concentrated form and fuel oil as it enters the furnace. Because the oxygen accelerated combustion produces such an intense flame, the tendency is for the straight flame to cut a hole through the scrap leaving a considerable mass of the charge untouched and the means for causing the flame to diverge is of increased importance. It is, however, more than ever, dangerous to use the known devices for causing divergence which may easily result in the diverging flame striking the side walls of the furnace, and it remains equally important in the refining period to provide the long luminous flame.

According to the present invention there is provided in a burner of the kind described having a passage for atomized oil under pressure, flame divergence controlling means adjustable between two extreme positions in one of which the flow in the passage is straightened thereby eliminating the minor turbulence referred to and in the other of which a whirling motion is imparted to the atomized oil which causes it to spread out in the form of a cone after leaving the end of the burner tube.

The result is to provide a burner which is of particular importance where combustion is ac celerated by the use of concentrated oxygen in the melting and refining of scrap iron and steel as described in the above-mentioned application of the present applicant and F. G. Kerry and which may be readily adjusted during operation so that during the heating and melting period the desirable diverging flame may be provided without danger of the flame striking the side walls, and during the refining period any turbulence in the burner tube tending to interfere with the desired parallel flow is eliminated.

Theadjusting means according to the invention consists of a ribbon-like piece of spring steel fixed at one end and; connected: at the other to means such as a rod operable from outside the burner tube in order to twist the fiat piece of spring steel or flatten it out as desired.

The invention will now be described. with reference to the accompanying drawing inv whichr Figure 1 is a sectional view of a burner provided with the flame divergence; controlling,

means according to the invention, and

Figure 2 is an enlarged view of the part of Figure 1 illustrating the twisted piece of spring steel.

Referring to Figure 1 the burner, indicated generally by the reference numeral Ill, projects through the end wall 1 I of the furnace and comprises essentially a burner tube l2 forming apassage for atomised oil under pressure, a tube. l3 surrounding the burner tube 12 for supplying fuel gas or oxygen and a water jacket 14 having an inlet i and an outlet l6. Fuel gas or. oxygen is fed to the tube 13 through an inlet I! and. a mixture of steam and atomised oil from the atomiser it! is fed to the burner tube [2 by means of a curved tube i9, which is of the same diameter as the burner tube 12 and merges with it in a gradual curve such that the oil is not thrown out of suspension. The atomiser 18 having an oil pipe 2% and a steam inlet 2| is advantageously placed in the vertical position illustrated since this arrangement avoids the clogging of the burner tube which results from dripping of oil from the end of the oil pipe in the conventionally placed atomiser.

The flame divergence controlling means is preferably a flat ribbon-like strip of spring steel 22 secured at one end to a rod 23 and at the other end anchored centrally of the burner tube 12 by connection to a pin 24 extending across the burner tube. A yoke 25 embraces the. pin 24, and the end of the strip 22, having been inserted between the ends of the yoke, is welded or otherwise suitably connected thereto.

The rod 23 extends lengthwise of the burner tube and, having passed through a gland (not illustrated) in the wall of the tube I9 and through the end 28 of the burner tube It, is provided with an operating handle 21. In order that the rod 2'3 may be locked in a given position of adjustment, the rod 23 is passed through a block 28 which is connected by an arm 29 to the end 26 of the burner tube I2 and provided with a locking screw 30. Preferably, also, the rod is provided with a marked disc 3|v adapted to rotate with the rod and, in cooperation with a pointer 32 fixed on the end of the burner 12, to indicate the degree of twist of. the strip 22.

As the handle 2'? is turned in one direction or the other, the rod 23 moves longitudinally of the burner tube and if desired" the portion of the rod cooperating in this movement with the end 26 of the burner tube 12 is provided with a thread 33 engaging with corresponding grooves formed in the end 26.

It will be apparent that the strip 22 instead of being normally flat and forced into the position illustrated may be normally twisted and forced to the flat position and that in either case adjustment is provided between two extreme positions in one of which turbulence is eliminated while in the other the mixture leaving the end of the burner tube is caused to diverge to any desired extent.

What I claim is:

1. In a fuel oil burner for open hearth furnaces having a passage for atomized oil under pressure, in said: passage for controlling divergnce of such. atomized oil under pressure after leaving the burner said means being adjustable between two extreme positions in one of which turbulence in the flow in said passage is eliminated and in the other of which a whirling motion is imparted to the atomized oil, said divergence. controlling means comprising a ribbonl'ikeflexible strip extending longitudinally of said passage, means fixing one end of said strip centrally in said passage, and a rod connected to the other end of said strip and mounted for rotation from the outside of said burner to adjust the strip between fiat and twisted condition.

2. In a fuel oil burner for open hearth furnaces having a passage for atomized oil under pressure, in saidpassage for controlling divergence of such atomized oil under pressure after leaving the burner said means, being adjustable between two extreme positions in one of which turbulence in the flow in said passage is eliminated and in the other of which a whirling motion is imparted to the atomized oil, said divergence controlling means comprising a ribbon-like strip of spring steel extending longitudinally of said passage, means one end of said strip centrally in said passage, and a rod connected to the other end of said strip and mounted for rotation from the outside of said burner to adjust the strip between fiat and twisted condition.

1-3. In a fuel oil burner for open hearth furnaces having a passage for atomized oil under pressure, means in said passage for controlling divergence of such atomized oil under pressure after leaving the burner, said means being adjustable between two extreme positions in one of which turbulence in the dew in said passage is eliminated and in the other of which a whirling motion is imparted to the atomized oil, said divergence controlling comprising a ribbon-like strip of spring steel extending longitudinally of said passage, a pin anchored centrally of said passage, means connecting one end of said strip to said pin, and a rod connected to the other end of said strip and mounted for rotation from outside the burner to adjust the strip between fiat and twisted condition.

i. Divergence controlling means in a fuel oil burner as defined in claim 1, comprising means for locking the said rod in a given position.

5. Divergence controlling means in a fuel oil burner as defined in claim 1, comprising indicarneans in connection with the said rod adapted to indicate the fiat condition of the strip and departure therefrom.

EDWARD T OMAS WALTER BAILEY.

CITED The following references are of record in the file or this patent:

UNITED STATES PATENTS 2,212,064 Berthiaume et a1. Aug. 20, 1940 FOREIGN PATENTS Country Date Germany Sept. 2'7, 1911 Number

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