US3680785A

US3680785A - Oxy-fuel burner for reducing the level of operating noise

Info

Publication number: US3680785A
Application number: US50442A
Authority: US
Inventors: Keith A Miller
Original assignee: Air Products and Chemicals Inc
Current assignee: Air Products and Chemicals Inc
Priority date: 1970-06-29
Filing date: 1970-06-29
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01
Also published as: FR2098101A5; GB1358587A; BE769172A; JPS5514327B1; DE2131825A1; NL7108915A

Abstract

A metallurgical burner of the type having a nozzle end for producing a flame by combustion of fuel and an oxidizing fluid. The burner is characterized in that the nozzle contains a plurality of mixing cups surrounding and projecting beyond a plurality of pairs of fuel and oxidizing fluid discharge ports. The mixing cups are sized so that combustion takes place inside or at the mouth of each cup thereby reducing the operating noise level of the burner. Further features of the burner include fluid cooling and quick change capability for nozzle end replacement.

Description

0 United States Patent 1151 3,680,785 Miller 1 1 Aug. 1, 1972 [54] OXY-FUEL BURNER FOR REDUCING 3,202,201 8/1965 Masella et al ..239/132.3 THE LEVEL OF OPERATING NOISE 2,433,610 12/1947 Hughey ..239/l 32.3 [72] lnventorz Keith A. Miller, Allentown, Pa. Primary EXaminer M Henson wood Jr. [73] Assignee: Air Productsand Chemicals, Inc., Assistant Examiner-John J. Love Allentown, Pa. Attorney-Ronald B. Sherer, James C. Simmons and 221 Filed: June 29, 1970 Kiev [21] Appl. No.: 50,442 [57] ABSTRACT A metallurgical burner of the type having a nozzle end 52 us. c1 ..239/132.3, 239/433 for producing a flame by combustion of fuel and n 51 1111. C1. .3051, 15/00 oxidizing fluid- The burner is Characterized in that the 58 Field of Search .239/132, 132.1, 132.3, 433 nozzle contains a plurality of mixing P surrounding and projecting beyond a plurality of pairs of fuel and [56] References Cited oxidizing fluid discharge ports. The mixing cups are sized so that combustion takes place inside or at the UNITED STATES PATENTS mouth of each cup thereby reducing the operating noise level of the burner. Further features of the 3,198,436 KLll'ZlnSkl t 3i. burner include cooling and

quick change p

3,1 18,608 1/1964 Berry ..239/132.3 bility for nozzle end repiacement 2,861,628 11/1958 Fraser ..239/132.3 X 3,043,577 7/1962 Berry .;.239/l32.3 6 Claims, 5 Drawing Figures PATENTEDAuc 1 I972} 3,680,785

sum 1 or 2 FIG. 2.

FIG I KEITH AMILLER INVENTOR AT TORNEY PATENTED 1197? 3.680.785

SiIIiET 2 BF 2 FIG. 3.

FIG. 5. FIG. 4.

KEITH A. MILLER INVENTOR.

ATTORNL Y BACKGROUND OF THE INVENTION This invention pertains to a metallurgical burner of the type used in melting vessels for melting primary metals. Such burners are commonly employed to melt large volumes of metallurgical scrap that is to be subsequently refined. The burners are normally placed in the wall or the roof of the furnace and employ an oxyfuel mixture that is combusted and directed at the metals being melted.

A burner of this type is shown in US. Pat. No. 3,1 18,608. The aforementioned patent shows a plurality of individual pairs of fuel and oxygen conduits that terminate at the bottom surface of a slotted aperture on the outer surface of the burner nozzle. The burner nozzle in the outward end thereof contains a plurality of these slots where the pairs of oxygen and fuel conduits supply a mixture to the surface of the burner nozzle. In a burner of this type, combustion generally takes place forward of the outermost surface of the burner nozzle. This results in a high operating noise level. Such a high operating noise level is disturbing to the human ear and in certain instances has caused loss of human hearing.

SUMMARY OF THE INVENTION The present invention relates to a metallurgical burner that can produce melting temperatures for primary metal refining vessels using a fuel and oxidizing fluid mixture- The burner of the present invention is fluid cooled and is provided with a plurality of mixing cups on the outward end of the burner nozzle to significantly decrease the operating noise level of such a burner. The mixing cups insure that combustion takes place at the mouth of each cup or inwardly thereof so that the flame front never leaves the face of the burner. The vburner of the present invention is readily fabricated and can be made in two sections with a quick change capability so that the nozzle end can be easily replaced. 1

Therefore, it is the primary object of this invention to provide an improved metallurgical burner.

It is a further object of this invention to provide a metallurgical burner for primary melting that operates at significantly reduced noise levels.

It is still another object of this invention to provide a metallurgical burner of the oxy-fuel type that is fluid cooled so that it can survive its operating environment.

It is still a further object of this invention to provide a metallurgical burner of the oxy-fuel type that is fluid cooled and that can be quickly disassembled to replace the nozzle end thereof.

BRIEF DESCRIPTION OF THE DRAWING DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 there is shown a metallurgical burner 10. The burner is preferably fabricated with a two-

piece housing

12 and 14. The housing sections 12-14 are secured together by a quick disconnect coupling 16 such as manufactured under the tradename VICTAULIC by the Victaulic Company of America. Such couplings 16 are well known to the industry and sealed by a pair of circumferential grooves 18 and 20 disposed in the housing sections of 12-14. As an integral part of the coupling there is a gasket or sealing member 22 to prevent fluid leaks from the burner.

The upper section 14 of burner 10 has a cap 24 affixed thereto as by circumferential weld 26. The cap 24 contains a central opening 28 for receiving a longitudinal conduit 30 of housing section 12. A plurality of recesses on surface 28 contain a corresponding number of O-ring type sealing members 32 to insure fluidtight sealing of the cap 24 to the conduit 30. It is preferable that at least three sealing members 32 be used so that there is in effect two pressure seals in each direction. Mounted on top of cap 24 is a conduit 36 which also contains an end cap 34. Disposed on the end cap 34 is a fluid conduit 38 that communicates with a central aperture 40 in cap 34. The aperture 40 in'cap 34 contains an O-ring sealing member 42 to assure a fluid-type seal between cap 34 and central fluid conduit 44. The central fluid conduit 44 projects into conduit 38 for receiving a fluid coolant from a source not shown.

Conduit 36 contains a suitable coupling 46 for receipt of a fluid conduit not shown. Coupling 46 can be a flange welded to conduit 36 and communicating with aperture 48 in conduit 36 for conducting a suitable oxidizing fluid into the inner area 50 defined by conduit 36 and conduit 44 and then into he interior area 52 defined by conduit 30 and conduit 44 and into the nozzle of the burner as will hereinafter be more fully described.

The lower housing 12 of the burner 10 has affixed to its lower end a nozzle shown generally as 54. The nozzle 54 contains a plurality of generally cylindrical mixcan be conducted from conduit 38 through conduit 44 FIG. 1 is a fragmentary section taken along lines l-- to chamber 60 radially outwardly of the nozzle through passages 58 and then to passage 62 defined by the interior wall of housing 12 and the exterior wall of an inner sleeve 64 that is affixed to the nozzle 54 as by circumferential weld 66. The fluid is then conducted outwardly of the burner through aperture 68 in housing 12 by means of a coupling 70 affixed to the housing, the coupling receiving a fluid conduit such as a hose.

The sleeve 64 in communication with conduit 30 defines an annular passage that communicates with an aperture 72 in housing 14. The aperture 72 has connected thereto in fluid tight engagement therewith conduit coupling 74 for receipt of a fuel such as natural gas. The fuel path, from coupling 74 through aperture 72 between sleeve 64 and conduit 30 to he nozzle 54 is isolated from the fluid path by a suitable circumferential sealing member 76 which is mounted on the interior wall of housing 14. Between the outer wall of sleeve 64 and sealing member 76 is an O-ring seal 78 so that the burner sections can be sealed in fluidtight arrangement, yet can be readily separated.

The mixing cups 56 project inwardly from the outer surface 80 of noule 54 and terminate at a generally flat surface 82. Communicating with surface 82 are circumferential grooves 84 and 86 (FIG. 3) which in turn communicate with the passages defined by the sleeve 64 and conduit 30 and passage 52 (defined by conduits 30,40) respectively in the burner. As is shown in Figure the

grooves

84 and 86 are machined in the nozzle body so that as the fuel and oxidizing fluid streams leave the bottom face 82 of cup 56 they are caused to impinge upon one another within the cup 56. This assures mixing of the fuel and oxidizing fluid. More importantly it is believed that the impinging streams create a negative partial pressure (relative to the burner environment) at the bottom face 82 of cup 56 so that the flame front is retained at the mouth 88 of cup 56.

In operation conduit 38 is connected to a source of suitable fluid coolant such as water. Coupling 70 is connected to a hose or other device for removing the fluid coolant and disposing thereof or causing the same to be cooled and recirculated. Coupling 74 is connected by a suitable conduit such as a hose to a source of fuel such as natural gas. Coupling 46 is connected to a source of an oxidizing fluid such as oxygen by a suitable conduit. The burner can then be lowered partially into a melting furnace and survive its environment because it is fluid cooled. The oxygen and fuel are introduced into the mixing cups 56 where they are intimately mixed and combustion results at the mouth 88 of the cups or inwardly thereof. With combustion at this point the operating noise level is significantly reduced because the flame front has not been allowed to separate from the outer surface of the nozzle. Maintaining the flame front in this position significantly reduces the noise level because the flame front has no aerial path between it and the face of the burner nozzle. The following table sets forth tests of burners of this type with and without mixing cup, wherein sound levels were recorded when the burner was fired into the open air.

TABLE Firing Rate Noise Level (Decibels) (Millions of BTU/Hr) With Mixing Cups Without Mixing Cups 4 96 5 I08 6 l l5 10 l 19 l23 14 124 I5 l28 l6 l25 126 130 127 131 Examination of the foregoing table shows that for the burner with mixing cups the measured noise level is significantly lower. it is well known that at the 100 decibel level a reduction of 4 decibels is significant.

It has also been found from examination of the various data generated that the length to diameter ratio of the fuel gas passages must be extremely large. However, maintaining the ratio relationship of the mixing cup length to diameter will still assure a significant reduction in the noise level.

There is shown in FIG. 4 an end view of a nozzle according to the present invention wherein the fuel and oxygen passages are discrete conduits and 92, 93 respectively instead of grooves as shown with respect to the embodiment of FIG. 1. In this embodiment, the noule is constructed so that conduit 90 communicates with the source of oxygen as has been described with respect to FIG. 1 and the

fuel passages

92,93 communicate with the source of fuel as described in connection with the embodiment of FIG. 1. The nozzle of F IG. 4 is cooled in the same manner as is the nozzle of F 1G. 1 and to that end contains a central chamber 94 and radial passages 96 for conducting the fluid between the mixing cups and then to the inner wall of the housing of the burner and then outwardly thereof.

Having thus described my invention, the appended claims define what is desired to be secured by Letters Patent of the United States.

IClaim:

1. In a burner of the oxy-fuel type comprising a generally elongated housing with internal fluid cooling passages and internal fuel and oxidizing gas passages to produce and direct a flame at a nozzle end thereof, the improvement which comprises:

a nozzle containing a plurality of mixing cups extending inwardly from the outer surface of said nozzle and communicating with an internal relatively flat surface disposed normal to the longitudinal axis of the cup, containing a fuel aperture and an oxidizing fluid aperture, whereby said cups cause intimate mixing of the fuel and oxidizing fluid therein and help retain the flame front at or inwardly of the mouth of the cups to reduce the operating noise level of said burner, each of said cups having a length to diameter ratio of between 0.4 to 1.4;

the fuel and oxidizing fluid passages communicating with the respective fuel and fluid passages of said burner; and

means for cooling the nozzle with the cooling fluid used in the burner housing.

2. A burner according to claim 1 wherein the ratio of the cross-sectional area of oxidizing fluid passage to the cross-sectional area of the fuel passage is between 0.5 and 1.3.

3. A burner according to claim 2 wherein the cooling fluid enters the center of the nozzle and is conducted through a plurality of passages across the face of the nozzle to the sides thereof where it is directed into the housing for removal from the burner.

4. A burner according to claim 3 wherein the housing is made in fluidtight removable sections for easy replacement of the burner nozzle.

5. A metallurgical burner of the oxy-fuel type comprising in combination:

a generally cylindrical housing having a cover on one end and a nozzle on the other end;

the nozzle containing a plurality of mixing cups extending inwardly from the outer surface of said nozzle and communicating with an internal flat surface disposed normal to the longitudinal axis of the cup containing a fuel aperture and an oxidizing passages communicating with the fuel gas passage in the nozzle and another of the passages communicating with the oxidizing passage in the nozzle; means in the housing for introducing the fuel and oxidizing gas to the respective conduits and means in the housing for introducing and removing the coolthe housing having a plurality of internal passages for receiving cooling fluid, fuel and an oxidizing gas, the cooling fluid passages so constructed and arranged to introduce cooling fluid down the center 10 of the burner and up along the walls of the housing 6. A burner according to claim 5 wherein the inward surface of each of said mixing cups contains at least one oxidizing fluid aperture and a plurality of fuel apertures.

and then outwardly of said housing, one of the 353 IUNETED STATES PATENT e ,52m ra CERTEFIATE UF QQRREUHQN Patent N 3,680, 785 Dated August 1, 1972 Inventofls) K. A. Miller It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

T is

In the drawings Sheet 1, Figure l, the reference numeral 78 at the right-hand side of the Figure below the lower section arrow of section line 3-3 should be numeral 86.

Signed and sealed this 10thday of April 1973.

(SEAL) Attest:

-EDWARD M.PLET( IHER,JR. ROBERT GOTTSCHALK Attestlng Officer Commissioner of Patents

Claims

1. In a burner of the oxy-fuel type comprising a generally elongated housing with internal fluid cooling passages and internal fuel and oxidizing gas passages to produce and direct a flame at a nozzle end thereof, the improvement which comprises: a nozzle containing a plurality of mixing cups extending inwardly from the outer surface of said nozzle and communicating with an internal relatively flat surface disposed normal to the longitudinal axis of the cup, containing a fuel aperture and an oxidizing fluid aperture, whereby said cups cause intimate mixing of the fuel and oxidizing fluid therein and help retain the flame front at or inwardly of the mouth of the cups to reduce the operating noise level of said burner, each of said cups having a length to diameter ratio of between 0.4 to 1.4; the fuel and oxidizing fluid passages communicating with the respective fuel and fluid passages of said burner; and means for cooling the nozzle with the cooling fluid used in the burner housing.

5. A metallurgical burner of the oxy-fuel type comprising in combination: a generally cylindrical housing having a cover on one end and a nozzle on the other end; the nozzle containing a plurality of mixing cups extending inwardly from the outer surface of said nozzle and communicating with an internal flat surface disposed normal to the longitudinal axis of the cup containing a fuel aperture and an oxidizing gas aperture; and passages for circulating a cooling fluid throughout the nozzle, each of said cups having a length to diameter ratio of between 0.4 and 1.4, and the ratio of cross-sectional area of the oxidizing gas aperture to the cross-sectional area of the fuel aperture is between 0.5 and 1.3; the housing having a plurality of internal passages for receiving cooling fluid, fuel and an oxidizing gas, the cooling fluid passages so constructed and arranged to introduce cooling fluid down the center of the burner and up along the walls of the housing and then outwardly of said housing, one of the passages communicating with the fuel gas passage in the nozzle and another of the passages communicating with the oxidizing passage in the nozzle; means in the housing for introducing the fuel and oxidizing gas to the respective conduits and means in the housing for introducing and removing the cooling fluid.

6. A burner according to claim 5 wherein the inward surface of each of said mixing cups contains at least one oxidizing fluid aperture and a plurality of fuel apertures.