US3575142A - Support for inclined fume hood - Google Patents

Abstract

A method and apparatus for supporting an inclined tubular fusion welded wall fume hood above a ''''basic oxygen'''' process steelmaking furnace. A strongback support composed of structural Ibeams is disposed beneath the fume hood and is fixed thereto at the upper end of the inclined section. The hood is supported by the strongback on bearing surfaces interposed between the hood and the I-beams to permit relative movement therebetween in order to accommodate movement of the hood caused by thermal expansion in a downward direction.

Description

United States Patent 72] Inventor Andrew J. Sefcik Ridgewood, NJ. [21] Appl. No. 838,272 [22] Filed July 1,1969 [45] Patented Apr. 20, 1971 [73] Assignee Combustion Engineering, Inc.

' Windsor, Conn.

[54] SUPPORT FOR INCLINED FUME HOOD 6 Claims, 6 Drawing Figs. [52] U.S. Cl 122/7, 122/510 [51] Int. Cl F22b l/18 [50] Field ofSearch 122/7, 7 (A), 510

[56] References Cited UNITED STATES PATENTS 3,168,073 2/1965 Durham et al. 122/7 3,323,495 6/1967 Blaskowski 122/7 3,390,666 7/1968 Fink et al. 122/7 FOREIGN PATENTS 890,869 3/1962 Great Britain l. 122/7 Primary Examiner-Kenneth W. Sprague Attorneys-Carlton F. Bryant, Eldon H. Luther, Robert L. Olson, John F. Carney, Richard H. Berneike, Edward L. Kochey, Jr. and Lawrence P. Kessler section. The hood is supported by the strongback on bearing surfaces interposed between the hood and the I-beams to permit relative movement therebetween in order to accommodate movement of the hood caused by thermal expansion in a downward direction.

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INVENTOR ANDREW J. sEFcm ZZZM MOZZZZ/ ATTORNEY BACKGROUND OF THE INVENTION One process for the making of steel is the basic oxygen" or BOF process. This process involves the introduction of oxygen by means of a lance into an upright pivotally mounted converter vessel charged with molten pig iron, scrap, flux and other materials. When the oxygen is blown into the converter, large quantities of high temperature gases are evolved as a result of the oxygen reaction. These gases contain about 90 percent CO and 10 percent CO and are at a temperature of about 3000 F. After sufficient blowing of oxygen, the converter vessel is pivoted to tap the molten steel.

It is the general practice to provide fume hoods to ventilate the area in which the steel-making process is taking place and direct the high temperature gases evolved from the converter to a gas cleaning system. The fume hood construction generally includes an inclined section of considerable length having vaporizable fluid cooled tubular walls, the tubes being fusion welded to form a gastight chamber. A controlled circulation pump forces fluid through the tubes. As the gases I pass through the hood, they are burned by the introduction of air between the mouth of the converter vessel and the base of the fume hood. The burning of the gases converts the C to CO, and this heat is absorbed by the fluid in the tubular welded walls to produce steam or to operate as a pressurized hot water system.

It is necessary to incline the hood in order to permit proper orientation thereof to receive the high temperature gases from the converter vessel during the heat cycle of the steel-making process while permitting unrestricted pivoting of the converter vessel for receiving raw materials to make the steel and for pouring the molten metal after its formation. Additionally, the provision of the incline allows access to the converter vessel for necessary maintenance such as rebricking. A typical fume hood of such construction which accomplishes the aforementioned objectives is shown and fully described in U.S. Pat. No. 3,323,495 to H. J. Blaskowski entitled Hood Organization for Use with Converter Employed in Steel-Making Process.

SUMMARY OF THE INVENTION As noted above, the "basic oxygen" steel-making process cycle includes charging of the converter vesseLa cycle time in which oxygen is blown into the converter vessel, and tapping of the molten steel from the converter. The time for each complete heat is approximately 60 minutes and up to 24 heats per day may be produced. In view of the large cyclic temperature variations and the resulting thermal movement, supporting and maintaining the positioning of the inclined fume hood and the related fluid supply system present unique problems.

It is the purpose of this invention to provide a novel means for supporting the inclined hood for readily permitting the thermal movements thereof while maintaining the hood in specific orientation with respect to the converter vessel. A strongback support composed of I-beams is located beneath the inclined fume hood and is fixed to the hood at the upper end of the incline. The hood is supported by the strongback on bearing surfaces interposed between the hood and the l-beams to permit relative movement therebetween in order to compensate for the thermal movements of the hood.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view, partly in section, of the fume hood and strongback support of this invention.

FIG. 2 is a transverse sectional view of the hood of the invention taken generally from the line 2-2 of FIG. I.

FIG. 3 is a sectional view of the bearing surface of the invention taken generally from line 3-3 of FIG. 2.

FIG. 4 is a plan view of the bearing surface of the invention taken generally from line 4-4 of FIG. 2.

FIG. 5 is a transverse sectional view of a modified fume hood utilizing this invention.

FIG. 6 is a transverse sectional view of a modified fume hood utilizing this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown a converter vessel or furnace 10 within which the basic oxygen" or BOF steelmaking process is carried out. The converter vessel 10 is mounted on a trunnion ring 12 so as to be rotatable from its upright position to a position to receive molten pig iron, flux and other material upon charging or to pour the molten steel after the steel-making process is completed. During the steelmaking process, an oxygen lance 14 extends downwardly from a housing 16 mounted on the structural support assembly 17 and is lowered into the converter vessel 10 with oxygen being blown into the material in the converter from a position above the molten bath at the bottom of the converter. While this process is being carried out, large quantities of gases are evolved and are directed to the mouth 18 of the converter 10. These gases are at a temperature of approximately 3000 F. and contain about percent CO and 10 percent CO A fume hood indicated generally as 20 is positioned above the mouth 18 of the converter 10 to receive the gases evolved therefrom. The fume hood organization 20 is inclined so as to direct the gases to a gas cleaning system (not shown) while facilitating access to the converter 10 in order to permit unrestricted loading and unloading thereof as well as for maintenance purposes.

The lower inlet 22 of the fume hood organization 20 is positioned above and spaced slightly from the mouth 18 of the converter 10. The spacing permits the air necessary to support combustion of the efiluent gases to enter the burning zone 24 of the hood organization 20 so that the CO can be converted to C0 The gases which are substantially completely burned then egress from the upper end 26 of the hood organization to a remote discharge duct 28. The remote duct 28 may lead to a gas cleaning system or a stack and have an induced draft fan (not shown) located therein to propel the exhaust gases.

In order to take advantage of the large quantities of heat developed from the evolved gases and the burning thereof, the hood organization comprises tubular welded walls 30 having a surrounding casing 32 for personnel protection. The tubes 30 are connected by outlet conduits 34 and inlet conduits 35 to a steam collecting connection 34' and a boiler water downcomer 35, respectively, of a steam drum 36. The drum 36 additionally has a feedwater supply conduit 36' and a steam outlet conduit 36" connected thereto to provide a positive circulation for the steam generator circuit. Water is forced through the tubes 30 by means of a pump 37. In the passing through the tubes 30, a portion of the water is converted to steam and the steam and water mixture that develops passes through the drum 36 wherein the steam is separated from the water with the steam being conveyed to a desired point of use through outlet 36" while the water is returned to the tubes 30 through downcomer 35'. A more detailed explanation of the steam generation circuit and general hood organization may be found in the aforementioned U.S. Pat. No. 3,323,495.

As mentioned above, the gases evolved in the basic oxygen" steel-making process are at a high temperature. Additionally, the basic oxygen" process is of a nature such that significant cyclic temperature variation occurs within the fume hood organization 20. This temperature variation results in a thennal expansion and contraction of the hood organization 20 of a magnitude of approximately I inch per 10 feet of hood length. Since an average hood length is approximately 70 feet, thermal expansion results in a movement of about 7 inches at the point just above the converter vessel 10. To accommodate this thermal movement while adequately supporting the fume hood organization 20 to maintain the opening between the hood and the converter vessel 10, a novel support arrangement 38 is hereinbelow described.

A strongback comprised of longitudinal l-beams 40 is fixed at the uppermost portion by means of connecting webs 42 to the structural I-beam 44 of the structural support assembly 17 and at the lower ends by means of connecting webs 46 to l beam 48 of structural support assembly 17. The hood organization 20, at its upper end, is also connected to the structural support assembly 17 by means of a rigid connection member 50. To provide a transverse line support arrangement for the hood organization 20, transverse l-beams 52 are fixed at points along the length of the longitudinal l-beams 40, as best seen in FIGS. 2, 3 and 4.

The casing 32 is provided on its underside with bearing surfaces 54 which may be of the self-lubricating type, such as for example, commercially available Lubrite fittings. The upper surfaces of the transverse l-beams 52 support the inclined hood organization 20 by resting against the bearing surfaces 54. Stops S6 serve as retainers for the bearing surfaces 54. By means of this interactive support, upon thermal movement the bearing surfaces 54 will move relatively to the transverse l-beams 52 in a sliding orientation so as to permit free thermal expansion and contraction while maintaining proper support for the fume hood organization 20 FIGS. 5 and 6 show cross-sectional views of modified hood organization configurations with primed and double primed numerals representing equivalent structure shown in the cross-sectional view of HO. 2. More specifically, in FIG. 5 the hood organization consists of tubular fusion welded wall 30 having casing 32' and being supported by longitudinal l-beams 40. The hood organization is in the cross-sectional configuration of a regular polygon, specifically being octagonal in shape. The number of l-beams 40' and their location is dependent on the particular hood organization but is generally based upon the necessity of providing sufficient balanced support for the hood organization while maintaining easy access for maintenance thereto. As in the modification of FIG. 6 where the hood organization is of a cross-sectional configuration of a circle, three l-beams 40" are necessary for balanced support. In the FIG. 5 modification, the transverse lbeam 52' is foreshortened to the length of one side of the polygon while in the FIG. 6 modification the transverse lbeams 52" are merely feet which mate with the bearing surfaces 54".

From the foregoing, it is apparent that there is herein described a novel support structure for a fume hood organization for use in the basic oxygen" steel-making process wherein the support permits thermal movement of the hood while maintaining easy access to the hood and converter for the maintenance and operation thereof. By rigidly retaining the hood organization at its uppermost point and positioning a strongback support, which at points therealong interacts with bearing surfaces on the hood organization beneath the inclined hood, the hood is permitted free thermal movement with a constant support not effected by the thermal expansion or contraction. By the particular positioning of the strongback support, the sides and top of the inclined hood are maintained clear for maintenance and operation purposes as is the area adjacent the converter vessel.

Iclaim:

l. A fume hood organization for use in cooperation with the converter vessel of a steel-making apparatus, the organization comprising: structural support assembly for said steel-making apparatus, an elongated inclined chamber open at both ends, strongback support means for supporting said chamber along its inclined length, said strongback support being fixed to said structural support assembly so that said chamber is positioned at one end with respect to said converter vessel so as to receive effluent gases therefrom and positioned at the other end with respect to a point of discharge to pass said gases thereto; connector means rigidly fixing one end of said chamber to said strongback support means; and bearing surfaces positioned between said strongback support means and said chamber so as to accommodate relative movement therebetween while maintaining the su port of said chamber.

The organization of claim 1 w erern said chamber [5 comprised of tubular fusion welded walls permitting the circulation of vaporizable fluid therethrough and having an outer protective casing.

3. The organization of claim 2 wherein a cross-sectional plane through said chamber describes a regular polygon.

4. The organization of claim 3 wherein said strongback support means includes at least one inclined l-beam fixed to said structural support assembly, said l-beam located beneath and spaced parallel to the longitudinal axis of said chamber, and a plurality of transverse l-beams positioned at fixed points across said first mentioned l-beam and juxtaposed to said bearing surfaces.

5. The organization of claim 2 wherein a cross-sectional plane through said chamber describes a circle.

6. The organization of claim 5 wherein said strongback support means includes at least two inclined l-beams fixed to said structural support assembly, said l-beams located beneath and spaced symmetrically parallel to the longitudinal axis of said chamber, and a plurality of feet positioned at fixed points on said l-beams so as to be juxtaposed to said bearing surfaces.

Claims (6)

1. A fume hood organization for use in cooperation with the converter vessel of a steel-making apparatus, the organization comprising: structural support assembly for said steel-making apparatus, an elongated inclined chamber open at both ends, strongback support means for supporting said chamber along its inclined length, said strongback support being fixed to said structural support assembly so that said chamber is positioned at one end with respect to said converter vessel so as to receive effluent gases therefrom and positioned at the other end with respect to a point of discharge to pass said gases thereto; connector means rigidly fixing one end of said chamber to said strongback support means; and bearing surfaces positioned between said strongback support means and said chamber so as to accommodate relative movement therebetween while maintaining the support of said chamber.

2. The organization of claim 1 wherein said chamber is comprised of tubular fusion welded walls permitting the circulation of vaporizable fluid therethrough and having an outer protective casing.

3. The organization of claim 2 wherein a cross-sectional plane through said chamber describes a regular polygon.

4. The organization of claim 3 wherein said strongback support means includes at least one inclined I-beam fixed to said structural support assembly, said I-beam located beneath and spaced parallel to the longitudinal axis of said chamber, and a plurality of transverse I-beams positioned at fixed points across said first mentioned I-beam and juxtaposed to said bearing surfaces.

5. The organization of claim 2 wherein a cross-sectional plane through said chamber describes a circle.

6. The organization of claim 5 wherein said strongback support means includes at least two inclined I-beams fixed to said structural support assembly, said I-beams located beneath and spaced symmetrically parallel to the longitudinal axis of said chamber, and a plurality of feet positioned at fixed points on said I-beams so as to be juxtaposed to said bearing surfaces.

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