US3501579A - Metallurgical furnace effluent conducting apparatus - Google Patents

Description

March 17, 1970 E, H, NAs|ER0w5K| ET AL 3,501,579.

METALLURGICAL FURNACE EFFLUENT CONDUCTING APPARATUS Filed Aug. 14. 1968 4 Sheets-Sheet 1 March 17, 1970 E, NAslERQwsKl ET AL 3,501,579

METALLURGICAL FURNACE EFFLUENT CONDUCTING APPARATUS Array/EY March 17, 1970 E, H, NAsl-ERowsm ET AL 3,501,579

METALLURGICAL FURNCE EFFLUENT CONDUCTING APPARATUS Filed Aug. 14, 1968 l 4 Sheets-Sheet 5 @Si Cim March 17, 1970 E, H, NAS|ERQW5K| ET AL 3,501,579

METALLURGICAL FURNACE EFFLUENT `CONDUCT-ING `APPARATUS Filed Aug. 14. 1968 4 Sheets-Sheet 4 I I `CEI Q:

WML/4M A. 5cl/Mackie .Ez/@EME H. /VAs/feowk/ INVENTORS BYJCM@ 4r raw/ff 'United States Patent 3,501,579 METALLURGICAL FURNACE EFFLUENT CONDUCTING APPARATUS Eugene Henry Nasierowski, Aliquippa, and William Albert Schmucker, Bethel Park, Pa., assignors to Kaiser Industries Corporation, Oakland, Calif., a corporation of Nevada Filed Aug. 14, 1968, Ser. No. 752,569 Int. Cl. Hb 7/18 U.S. Cl. 13-1 14 Claims ABSTRACT 0F THE DISCLOSURE An apparatus for mounting a duct or elbow adjacent to but separate from a metallurgical furnace for fore and aft and tilting movements so as to enable limited movement of the furnace relative to the duct with the duct in operating position, to enable adjustment of the gap between the duct and the exhaust opening of the furnace without appreciably affecting the gap at the opposite end of the duct, and to enable movement of the duct away from the furnace to allow for full movement of the furnace and its roof and for maintenance purposes.

BACKGROUND OF THE INVENTION The present invention pertains to an effluent conducting apparatus which establishes effective communication with the exhaust opening of a metallurgical furnace without interfering with other operations of the furnace.

As is well known, apparatus is typically provided for conducting fumes from a metallurgical furnace through gas cleaning equipment to a stack. The conducting apparatus of the present invention is intended for this purpose and although having general utility with various metallurgical furnaces, it is especially suited for use with an electric furnace.

The effluent conducting apparatus known to be in use with electric furnaces prior to the present invention has certain disadvantages. For example, a common way of removing off-gases from an electric furnace is to mount a fume-collecting elbow on the furnace roof ring with one end of the elbow positioned directly over the exhaust opening in the roof to define a rst gap and with the opposite end of the elbow in adjacent spaced relation to a stationary duct to define a parting line or second gap. A disadvantage here is that the elbow has to be removed in order to change the roof because the roof lifting means cannot be rotated with the elbow in place. The time required to remove and to re-install the elbow greatly increases the downtime required to change a furnace roof. Secondly, in order to provide the second gap noted above, very cumbersome and expensive transitions and flanges, which are subject to distortion and damage, have been required. This second gap has also increased the total amount of fan capacity required for the effluent control system. A third disadvantage is the necessity of mounting the gap adjusting mechanism on the furnace; suc-h mounting subjects the adjusting mechanism to the extreme heat of the furnace and also complicates roof change.

Another type of mounting has been to support such an elbow from the furnace roof lift beams which thereby facilitates roof change because the elbow can then be rotated with the lift beams. However, the disadvantages associated with the gaps at the opposite ends of the elbow still remain with this type of mounting.

Another proposal has been to support a long duct, incorporating an elbow, independently of the furnace so that it can swing up and down. With this arrangement, it `would be necessary to locate the pivot for the swinging elbow far enough from the furnace to provide clearance between the scrap charging bucket and the elbow when the latter is in the raised position. Also, considerable power and travel would be required to swing the cumbersome duct through a large arc, and repair and maintenance of the duct in its raised position would be very difficult. Further, slag, scrap and dust Whic-h collect in the duct during operation would fall to the bottom of the swinging duct when it is raised to a vertical position, such material presenting both safety and cleaning problems and cau-sing wear and damage to the duct.

SUMMARY OF THE INVENTION The present invention solves the foregoing problems by mounting an elbow or duct independently of the furnace for fore and aft movement between a conducting or 0perating position, with the receiving end of the duct in adjacent spaced communicating relation with the exhaust opening of the furnace while allowing limited tilting of the furnace, and a retracted position spaced far enough from the furnace to enable full movement of the furnace and its roof and to enable maintenance of both the furnace and the duct. Furthermore, the duct is also mounted for tilting movement to enable adjustment of the gap between the duct and the exhaust opening of t-he furnace when the duct is in its conducting position and without appreciably affecting the gap at the parting line between the movable duct and the stationary ductwork of the gas cleaning system. The fore and aft and tilting movements provided by this mounting can be effected simultaneously or independently thereby affording close control over the position of the duct.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of the effluent conducting apparatus of the present invention shown in association with part of a gas cleaning system and with an electric furnace which is partially indicated in dashed and section lines.

FIG. 2 is a top plan of the structure shown in FIG. 1.

FIG. 3 is a rear elevation of the structure of FIG. 1 as viewed from a position at the right thereof.

FIG. 4 is an enlarged fragmentary view of a portion of the apparatus shown in FIG. 3.

FIG. 5 is an enlarged fragmentary view of a portion of the apparatus shown in FIG. 1, but with parts being broken away.

DETAILED DESCRIPTION The eluent conducting apparatus of the present invention is generally indicated by the number 10 in FIGS. 1 and 2 and is shown for conducting fumes from an electric furnace, generally indicated -by the number 12, to a gas cleaning system, only partially indicated, and identied generally by the number 14. The electric furnace is tiltable about axis A, has a side wall 16 and a removable or swingable top wall or roof 18. The roof has a plurality of electrode openings 20 and a circular exhaust opening 22 located relatively adjacent to the outer edge of the roof. It is through this exhaust opening that the fume, including dust particles entrained in gas, is discharged from the furnace. The furnace is referred to herein only by way of environment and since the construction and operation thereof are well known, no further description is believed necessary.

The gas cleaning system 14 has a stationary duct 26 which is horizontally disposed and laterally spaced from the lfurnace 12 at about the same level as the roof 18. The stationary duct has a rectangular inlet 28 provided with a rim 30 to which is attached coolant pipes 32.

The subject apparatus includes a main support frame 40 (FIGS. l and 2) spaced from the furnace by about the same distance as the stationary duct 26. This frame has front and rear horizontal transverse beams 42 and 44 spaced below the stationary duct 26 and supported on legs 46 which are interconnected by bracing 48 and rest on a floor 50 of the steel plant. A pair of transversely spaced side beams 52 are rigidly supported on the front and rear beams, with one of the side beams being located underneath the stationary duct 26, as best shown in FIG. 2.

A tiltable frame 60 is located between and pivotally supported on the side beams 52 of the support frame 40. The tiltable frame has a pair of elongated side members 62 (FIGS. 1, 2 and 4), these side members being provided with front ends 64 located relatively adjacent to the furnace 12 and opposite rear ends 66. Trunnions 68 project laterally from the side members, are journalled in bearings 70 on the side beams 52 and define a pivot axis for the tiltable frame that is perpendicular to the axis A. U-shaped cross members 72 have opposite ends connected to the bottoms of the side members and extend transversely therebetween to interconnect the side members and provide rigidity for the tiltable frame.

The side members 62 of the tiltable frame 60 provide inwardly facing, U-shaped trackways 76 and 78 (FIGS. l and 4) which extend lengthwise of the tiltable frame 60. The trackway 78 is provided with an upper rail 80 and a lower rail 82. Although trackway 76 is shown as smooth, it could also be equipped with such rails. Front and rear cross pieces 84 and 86 extend between the side members 62 and have opposite ends projecting into the trackways.

For controlling the pivoting action of the tiltable frame 60, a mounting bar 90 (FIGS. 4 and 5) is supported on the rear beam 44 by brackets 92 on the rear beam connected by pins 94 to anges 96 on the mounting bar. Worm gear jacks 100 are individually supported adjacent to opposite ends of the mounting bar 90 and have screws 102 connected by pins 104 to brackets 106 which depend from the side members 62 of the tiltable frame. Each jack has a gear box 108 and a bellows boot 110. A reversible drive motor 116 is supported on one end of the mounting bar (FIG. 4) and has a drive shaft 118 extending through the gear boxes. In a well known manner, worm gears, not shown, are connected to the drive shaft within the gear box and are in mesh with driven gears, also not shown, of the jacks. As will be understood, rotation of the drive shaft will rotate the screws thereby to pivot the tiltable frame about the generally horizontal axis defined by the trunnions 68 and bearings 70. By reversing the motor the front end of the tiltable frame can be moved up or down.

Upper and lower limit switches 126 and 128 are mounted on the inside of one of the side beams 52, and a switch arm 130 projects from the adjacent side member 62. When the tiltable frame 60 is in a neutral position, the switch arm is located equidistantly between the upper and lower limit switches, as shown in FIG. 4. Upon tilting of the frame 60, the switch arm will eventually engage one or the other of the limit switches for a purpose to be described.

The eiuent conducting apparatus 10 also includes a carriage 140 mounted in the tiltable frame 60 for fore and aft movement, lengthwise of the tiltable frame in the disclosed embodiment, toward and away from the electric furnace 12. This carriage has side beams 142 located individually adjacent to the side members 62 and cross beams 144 rigidly interconnecting the side beams. Bearings 146 are secured to the lower surfaces of the side members, and front and rear axles 148 are supported in these bearings. Each axle 148 has a cylindrical wheel 150 on one end thereof which is disposed in the smooth trackway 76 and a V-groo-ved wheel 152 on its other end which is in the trackway 78. The V-grooved wheels lit over the rails and 82 and thus constrain the carriage 140 to move fore and aft along a rectilinear path. The carriage is thus mounted for movement lengthwise of and relative to the tiltable frame with the wheels rolling in the trackways. It is to be noted that if trackway 76 is also provided with rails, the wheels therein would be shaped to iit such rails.

In order to control movement of the carriage 140, a depending rear bracket is secured to the rear cross beam 144 of the carriage (FIGS. 1 and 4). An air cylinder 162 has its front end 164 pinned to the front cross member 72 of the tiltable frame. A piston rod 166 working in the cylinder 162 is pivotally connected to the rear bracket 160 so that by extension and retraction of the rod, the carriage is moved lengthwise of the tiltable frame 60. Front and rear limit switches l and 172 are mounted on one of the side members y62 of the tiltable frame 60, and a switch arm 174 projects from the adjacent side beam 142 for contacting the limit switches in the conducting and retracted positions of the carriage respectively.

The carriage 140 supports an elongated movable duct or elbow having a receiving end portion 182, an intermediate portion 184, and a discharging end portion 186. Theduct 180 is releasably secured to the carriage by straps around the intermediate portion which are connected to spacers 192 disposed transversely of and secured to the side beams 142 of the carriage. The intermediate and discharging portions 184 and 186 of the duct are of generally uniform rectangular cross section with the discharging end portion terminating in a rectangular outlet 194 registerable with the inlet 28 of the stationary duct 26. The discharging end portion also has a rim 198 provided with coolant pipes 2.00. The receiving end portion of the duct diverges slightly from the intermediate portion and is provided with an oval inlet 202 disposed transversely of the duct. The inlet has a minimum dimension approximately equal to the diameter of the exhaust opening 22 and a maximum dimension parrallel to the pivot axis of the tiltable frame 60. The duct is preferably constructed with pipes extending about its periphery so that coolant water can be conducted therethrough.

In describing the operation of the subject apparatus 10, it is first assumed that the electric furnace 12 is in its upright position, that the furnace has been charged, and that the roof 18 is covering the furnace. By contracting the piston rod 166, the carriage 140 and thus the movable duct 180 are moved forward to a conducting or operating position, with the inlet 196 of the duct over the exhaust opening 22, so that the inlet 96 and the exhaust opening 22 are generally concentric as illustrated in FIG. 2, and with the outlet 1914 of the duct 180 and the inlet 28 of the stationary duct 26 in registration. In this conducting position, a furnace gap 210 is provided between the movable duct and the roof and a cleaner gap 212 is provided between the movable and stationary ducts.

After the inlet 196 has been positioned over the exhaust opening 22, the drive motor 116 may be energized to move the receiving end portion 182 of the movable duct 180 closer to or farther from the furnace roof 18, thereby to adjust the furnace gap 210. Alternative positions of the duct, and thus adjustment of the furnace gap, are indicated by the dashed lines immediately over the furnace in FIG. l. Furthermore, because the axis of the trunnions 68 is in adjacent parallel relation to the iiow axis of the inlet 28, neither the cleaner gap nor the registration of the inlet 28 and outlet 194 is appreciably affected by pivoting or tilting of the movable duct.

After the duct 180 is in its conducting position and the gap 210 has been properly adjusted, ignition can take place in the furnace 12. It is to be noted, however, that the limit switches 126, 128 and 170, 172 preclude certain operations and movements of the furnace and the furnace roof when the duct is not in a position which will allow such an operation or movement to take place. Thus,

movement of the duct 180 into its conducting position causes the switch arm 174 to engage the front limit switch 170 thereby to precondition the furnace for ignition but to preclude swinging or removal of the roof and full tilting movement of the furnace. Furthermore, the gap 210 must be maintained within a certain range or else the switch arm 130 will engage one of the limit switches 126 or 128 and preclude ignition or continuance thereof.

While the movable duct 180 is in its conducting position, as shown in FIGS. l and 2, there is sufficient room for the furnace 12 to be tilted within a predetermined minimum angular amount, for example 3 to 6, in either the tapping or slagging direction according to operating preferences. In this regard, the oval inlet 196 on the movable duct and oriented as described above allows for continued communication between the duct and the exhaust opening 22 throughout this range of tilting movement. It is believed understood that the tiltable axis A of the electric furnace is generally perpendicular to the pivot axis of the duct 180 and to the maximum dimension of the inlet 196.

When it is desired to change the roof 18 or to swing the same aside for top charging to tap or slag the furnace 12, or to maintain or otherwise service the furnace or conducting apparatus 10, the piston rod 166 is extended to move the duct 180 aft into its fully retracted position to one side of the furnace, as shown in dashed lines in FIG. 1. In this retracted position, the switch arm 174 contacts the rear limit switch 172 to prevent ignition of the furnace but to enable movements of the roof and full tilting of the furnace. The receiving end portion 182 of the movable duct is laterally spaced from the roof 18 as well as the side wall 16 of the furnace so that the duct is in a non-interfering relationship to the furnace. Both the furnace and the effluent conducting apparatus can easily be repaired, maintained or replaced while the movable duct is in its retracted position. The duct 180 can be removed from the carriage 140, placed on the floor 50, and another duct strapped to the carriage. This change can be made in a few minutes thereby allowing the furnace to be put back into operation while the removed duct is cleaned or otherwise serviced. Also, in the retracted position of the duct, the inside of the stationary duct 26 is readily accessible as visualized in FIG. 2. Because of the right-angular relationship between the intermediate and discharging portions 184 and 186 of the movable duct, adequate working space exists between the inlet 28 and the intermediate portion 184 when the movable duct is in its retracted position. Furthermore, the side member 62 and side beam 142 adjacent to the inlet 28 serve as a convenient Walkway to gain access on the inside of the stationary duct.

It is to be noted that the jacks 100 are spaced a considerable distance from the furnace 12 and thus are not subjected to its intense heat and are in position for easy maintenance. Furthermore, the cleaner gap 212 is not affected by furnace expansion or other distortions or by furnace tilt, whereas the furnace gap 210 can be adjusted to compensate therefor.

From the foregoing, it will be evident that an apparatus has been provided for mounting a fume conducting duct or elbow adjacent to but separate from a metallurgical furnace so that the duct can be moved fore and aft and also tilted either simultaneously with or independently of the fore and aft movement. The apparatus of the present invention meets the major requirements of an effluent conducting system for an electric furnace. It can be moved into a non-interfering position to allow for certain operational movements of the furnace and the roof without requiring dismantlement or detachment of the duct or elbow. It facilitates convenient adjustment of the furnace gap and maintains a constant minimal gap between the movable and stationary ducts while adjustments are made in the furnace gap. Expansion and other distortion of the furnace parts either do not affect, or can be readily cornpensated for by, the apparatus. In its operating position, the duct allows for limited furnace tilt without appreciably affecting the furnace gap or parting line gap. [In addition, the mechanisms for controlling movements of the duct are located away from the furnace so that they are not subject to the intense furnace heat and can more easily be maintained.

Although a preferred embodiment of the present invention has been shown and described, it will be understood that modifications and changes can be made therein without departing from the spirit and scope of the present invention as set forth in the appended claims.

What is claimed is:

1. An apparatus for conducting effluent from a metallurgical furnace which has a wall provided with an exhaust opening, a duct having opposite receiving and discharging end portions; first means for enabling movement of the duct along a predetermined path toward and away from the furnace between a conducting position, with the receiving end portion confronting said opening and defining a gap with said wall, and a retracted position with said entire duct spaced from said furnace; and second means for enabling movement of said receiving end portion transversely of said path toward and away from said wall to adjust said gap.

2. The apparatus of claim 1 wherein said furnace is an electric furnace, wherein said wall is the roof of the furnace, wherein said duct projects outward from said furnace, wherein said path is substantially rectilinear, and wherein said second means mounts the entire duct for tilting movement thereby to enable adjustment of said gap.

3. The apparatus of claim 1 including a support, said second means being mounted in the support, and said first means being mounted in said second means.

4. An apparatus for conducting effluent from a metallurgical furnace which has a roof provided with an exhaust opening, an elongated duct having opposite receiving and discharging end portions, and means mounting the duct for rectilinear movement lengthwise thereof between a conducting position with said receiving end portion over said openingand in closely spaced relation to said roof and a retracted position displaced from said roof, said means also mounting said duct for pivotal movement about an axis disposed transversely thereof so as to enable adjustment of the gap between said roof and receiving end portion in said conducting position of the duct.

5. The apparatus of claim 4 including a stationary duct having an inlet, said discharging end portion having an outlet registering with said inlet in said conducting position, said pivotal mounting means being adapted to adjust said gap while maintaining registration between said inlet and outlet.

6. The apparatus of claim 5 wherein said inlet and outlet are displaced from each other and said duct is spaced from said inlet in said retracted position to enable access to said inlet.

7. An effluent conducting apparatus for use with a furnace having a roof provided with an exhaust opening, a support, a tiltable frame, means mounting the frame in laterally spaced relation to the said furnace for tilting movement about a substantially horizontal axis, a carriage, a movable duct having an inlet and being mounted in the carriage, means supporting the carriage on the frame for movement of the duct along a path between a conducting position with the inlet of the duct in communication in said exhaust opening and a retracted position with said duct spaced from said furnace, and powered means for effecting said tilting movement and said movement along said path either independently or simultaneously in order to adjust the gap between the duct and the roof in said conducting position and to facilitate movement of the roof and maintenance of the furnace and the duct in said retracted position.

8. The apparatus of claim 7 wherein said furnace is tiltable, wherein said exhaust opening is circular, wherein said duct is elongated and has opposite receiving and discharging end portions, said receiving end portion having an oval inlet the minimum diameter of which is substantially equal to the diameter of said exhaust opening and the maximum dimension of which extends in the direction of tilting of the furnace, wherein in said conducting position of said conduit said opening and inlet are in communication, and wherein during tilting of said furnace said opening is moved into positions either concentric with or eccentric to said inlet while maintaining communication between said opening and said inlet.

9. The apparatus of claim 7 wherein said powered means includes an expandable drive mechanism connected to and between the frame and the carriage for moving the carriage along the frame, and said powered means also including another expandable drive mechanism connected to and between said support and said frame for tilting said frame.

10. The apparatus of claim 7 including a stationary duct having an inlet spaced from the furnace and located at about the same elevation as said exhaust opening, said movable duct having a substantially straight intermediate portion and a discharge portion perpendicularly extending from the intermediate portion and provided with an outlet which is in registration with the inlet of said stationary duct in said conducting position, said registering inlet and outlet havng a ow axis in adjacent parallel relation to said horizontal axis whereby said registration is maintained during tilting of the movable duct, said inlet of the stationary duct being exposed in said retracted position.

11. The apparatus of claim 7 whereby said movable duct has a generally rectangular cross section.

12. The apparatus of claim 7 including interengaging means on said carriage and frame for constraining move- 8 ment of said carriage along said path to rectilinear movement.

13. The apparatus of claim 7 wherein said fra-me has elongated inwardly facing trackways and wherein said supporting means includes wheels connected to said carriage and riding in said trackways.

14. The apparatus of claim 7 wherein said support includes laterally spaced side beams, wherein said frame is substantially rectangular and is disposed between said beams, said apparatus further comprising bearings on said beams and trunnions projecting from said frame and journalled in the bearings, wherein said carriage is substantially rectangular and is positioned within said frame, wherein said fra-me has tracks, wherein said supporting means includes Wheels riding in said tracks, wherein said powered means includes a piston-cylinder mechanism interconnecting said frame and said carriage, and wherein said powered means also includes powered jacks interconnecting said support and said frame on the opposite side of said trunnions from the furnace.

References Cited UNITED STATES PATENTS 2,684,392 7/1954 MoOre 13-10 2,908,737 10/ 1959 Dominicis 13--10 3,173,980 3/1965 Hysinger 266--34 3,379,426 4/ 1968 Reuter et al.

3,428,301 2/1969 Chermely 134-10 BERNARD A. GILHEANY, Primary Examiner H. B. GILSON, Assistant Examiner Us. c1. xn. is-io, 266-34

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