US 3592363 A
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United States Patent Ronald W, Stout Gary. lnd.;
John R. Albrecht. Grosse Point Park, Mich. 798,634
Feb. 12, 1969 July 13, 1971 Inland Steel Company Chicago, Ill.
lnventors Applv No Filed Patented Assignee DEVICE FOR ADDING FINE PARTICLE-SIZED SOLIDS TO A LIQUID STREAM 4 Claims, 4 Drawing Figs.
US. Cl 222/193, 302/56, 164/57, 266/34 T int. Cl 1B67d 5/54 Field of Search 222/193- References Cited UNTTED STATES PATENTS l/l904 Millspaugh 222/134 12/1908 Stromborg.... 266/34 X 2/1929 Allen 222/486 X 6/1938 Schanz 222/193 2/1956 Kolks 222/195 9/1966 Brown, Jr. et a1 266/34 (T) Primary Examiner-Robert A. Reeves Assistant Examiner-David A. Scherbel AttorneyMerriam, Marshall, Shapiro & Klose ABSTRACT: A device for adding fine particle-sized solids in a continuous casting operation whereby a uniform rate of addition of said solids is achieved by controlling the rate of flow of solids by means of a series of metering orifices in a feed bar attached to the bottom of a hopper and then propelling the particles through a series of tubes or conduits into the molten metal stream.
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k I k I NVENTORS M vac if" ATTORNEYS DEVICE FOR ADDING FINE PARTICLE-SIZED SOLIDS TO A LIQUID STREAM BACKGROUND OF THE INVENTION The subject invention relates to the production of alloys and particularly to a device for adding fine particle-sized solids to a liquid stream as the molten metal passes from a ladle to a tundish in a continuous casting operation.
The addition of fine-sized particles to steel has been disclosed by earlier patents. Inasmuch as most additive materials are easily oxidized at the high temperatures involved with molten steel, it is important that the material to be added he quickly and uniformly distributed throughout the steel and that the mixing operation be completed in as short a time as possible.
It is also important that the material be uniformly distributed to accomplish maximum effectiveness with a minimum use of the added material.
A number of devices have been suggested in the past for supplying lead pellets, metallic aluminum or other solids into a molten metal stream in an attempt to obtain thorough distribution of the material. An example of a device for adding aluminum shot is shown in US. Pat. No, 3,224,051 to Brown et al. issued Dec. 2 I 1965. Brown et al. includes a gun having a substantially horizontally positioned barrel through which an air stream flows, and a hopper for containing fine-sized particles mounted atop the barrel.
Brown et al. employs a vertical tube which communicates the bottom of the hopper with the gun barrel at a location adjacent to an air-jet nozzle extending into the gun barrel along the axis thereof. The air-jet nozzle is longitudinally adjustable along the axis of the barrel to vary the size of the opening which communicates the bottom of the hopper with the barrel and thereby controls the rate of flow of solid particles from the hopper in the gun barrel. A conduit extends from the barrel at a point downstream from the vertical tube into the hopper and diverts a portion of the airstream flowing through the barrel into the hopper to agitate the fine-sized solid particles in the hopper. The air stream emanating from the nozzle in the bar rel propels the particles through the barrel and into the stream.
The disadvantage of the device shown in Brown et al. is that it is designed to place a premeasured, relatively large amount of solid material of a lower density than the melt, into the melt in a short period of time, and is unsuited to furnish continuous and uniform supply of the solid, fine-sized material as is required when teeming ingots or in continuous casting. This is so because the design of the barrel in Brown et al. permits the backup of aluminum shot at the intersection of the barrel and the vertical tube from the hopper. Such a backup, at least in the case of lead particles, will vary the flow of metal into the liquid steel and, consequently, have a nonuniform effect on the metal.
In addition, the method required to fill the hopper causes the rate of flow of material to be varied. The air nozzle in the barrel is brought forward towards the vertical tube from the hopper in order to block off the flow of material as it is supplied to the hopper. The nozzle must then be withdrawn to the desired position which causes solid material to fill the voids in the barrel. When the airflow is commenced, the flow of metal is necessarily nonuniform until flow from the hopper and through the vertical tube is stabilized.
Where the linear application of fine-sized solids is critical, devices like Brown et al. are not suitable.
In addition. and most important, Brown et al. and similar devices in the art employ high quantities of air for propelling the fine-sized particles through the gun. For instance. Brown et al. allows the entire amount of airflow to proceed past the vertical tube and past that point where the airflow is broken into a component which proceeds through the barrel into the stream while some is diverted up into the hopper. A major portion of the air introduced into the barrel proceeds to the stream. Where oxidization may be critical, devices using such a large amount of air are unacceptable.
SUMMARY OF THE INVENTION The present invention is designed to remedy these disadvantages and provide a quick control and uniform supply of fine-sized particles. The device made in accordance with this invention consists of a gun having a barrel mounted for swiveling on a turret base. Mounted above the barrel and connected thereto by a conduit and vertical tube is a hopper for containing the fine-sized solid material. The barrel is inclined downwardly from the intersection with the conduit to facilitate the flow of the particles into the stream. An air or inert gas supply is employed primarily for the purpose of freeing the lead particles in the hopper and vertical tube rather than to propel the particles. Hereinafter reference will be made to air only for the sake of brevity. An airhose extends from the air supply source to the hopper where it is released through a nozzle located immediately above the vertical tube for agitating the fine-sized particles and drawing them into and through the vertical tube,
A second air supply and nozzle is located above the barrel and intersects the vertical tube at such an inclination so as to free the vertical tube of clogging and direct the particles into the barrel and downwardly toward the stream.
A metering bar having various size openings therethrough is disposed between the hopper and the barrel and limits the amount of material that can pass to the barrel.
With the nozzles so located and with the addition of such a metering bar, minimum amounts of air are required and a uniform, highly controllable rate of flow can be achieved.
The device of the present invention may be used to add lead, other alloying elements or fluxes.
DESCRIPTION OF THE DRAWINGS Further understanding of the subject invention can be had by reference to the drawings wherein:
FIG. 1 is an elevation of the subject invention;
FIG. 2 is a cross-sectional view of the gun used in the subject invention;
.FIG. 3 is an elevation of the housing used in the subject invention; and
FIG. 4 is a side view showing the use of the subject inventron.
DETAILED DESCRIPTION Referring first to FIG. 4, the device I0 is shown emitting particles into stream S as the stream travels from ladle L into tundish T. Referring now to FIGS. l-3, wherein common reference numerals will be used, the device 10 consists of an open topped hopper 11 positioned over barrel 14 and connected thereto by a housing 31. Hopper 11, barrel l4 and housing 31 are mounted on tripod 12 having a swivel arrangement for directing the flow of particles. Hopper 11 is shown in FIG. 2 partially filled with fine-sized particles which, for the purpose of this discussion, are lead particles in the amount desired to be added to stream S.
The sides of hopper 1] are tapered inwardly substantially from its open top to its base 20. Spaced above base 20 is a false bottom 26. In the space between base 20 and false bottom 26 there exists a channel 15 in which there is received a movable metering bar 16 having metering orifices or openings 28, 28, 28", and 28", said openings 28,28, 28", and 28" being of various diameters corresponding to the rate of flow of the material desired.
Mounted in the center of hopper 11 above false bottom 26 is an air injector 40 having a nozzle 42 spaced above aperture 41. Air is supplied to air injector 40 by means of airhose 18 which extends through a grommet 32 or the like through the side of hopper 11 to air supply source 17. The vertical distance between nozzle 42 and aperture 41 must be great enough to allow the particles in hopper II to be drawn into the aperture 41 by means of gravity and the suction caused by the air passing from nozzle 42 through aperture 41.
The rate of flow of particles from hopper ll may be varied by manipulating metering bar 16 in channel 15 so that the desired opening, e.g., 28 is in vertical alignment with aperture 41 and air injector 40. Guide bar 16 is secured in the desired position by means of a ball check 24 which is urged into detents 25 on metering bar 16 by means of spring 23.
Metering bar withdrawal limit 48 is provided to prevent metering bar 16 from accidentally being pulled back too far during operation and creating a full on" condition.
Base 20 is provided without a cleanout port 27 through which particles that are trapped within the space between false bottom 26 and base 20 can be removed. Channel E is provided with one or more recesses 30 into which particles which may otherwise impede the movement of metering bar 16 may fall.
Hopper 11 is mounted above'housing 31 which housing 31 includes a vertical bore 29 placed in vertical alignment with air injector 40, an injector line 32 and conduit 34.
Air injector line 32' includes an airhose 19 which is connected to air supply source 17 and a nozzle 33 through which air passes into vertical bore 29 at junction 38. Nozzle 33 enters vertical tube 29 at a downwardly directed angle in order to direct the flow of material from vertical tube 29 into conduit 34 and then to barrel l4.
Barrel 14 is an elongated tubular member having mounted at one end an air supply hose 35 connected to air supply source 17 and at the other end a nozzle 36. Immediately prior to nozzle 36 are pressure relief ports 21. A shield 47 is provided so that relief ports 21 vent into the encompassing shield 47, thereby creating an air-cooled nozzle 36. Shield 47 has the added function ofa splash guard.
Barrel I4 is positioned so that nozzle 36 is lower than the point at which conduit 34 intersects barrel 14. A sleeve 46 made of asbestos or other heat resistant material may be provided around barrel 14 to maintain the temperature of the barrel at an acceptable level.
In actual use, the device is set up and positioned near the point where the dry material is to enter the stream with the nozzle 36 of barrel 14 at some convenient distance from the stream. With the metering bar 16 positioned so that none of the openings 28, 28', 28", and 28" are in vertical arrangement with the vertical bore 29 and air injector 40, the hopper which can be of any convenient size is charged with the material to be added and the propelling pressure set to produce the required rate of flow. Prior to the actual use of the device, the flow rate of the material to be added to the stream must be determined experimentally. When the continuous casting is to be started and the stream begins to flow, metering bar 16 is moved from the closed position to the preselected open position. The flow rate is controlled by the combination ofthe selected meter orifices in the guide bar and the pressure of the propellant. Additions of the material to be fed are made to the hopper either manually or mechanically as required. By varying the diameter and internal shape of nozzle 36 of barrel 14 and/or by varying the size and number of the relief ports 21. the shape of the delivery stream can be regulated.
In the manufacture of lead bearing steels, it is desired to add from 4 to l2 lbs. per steel ton of very fine mesh lead shot, usually finer than 20 mesh (ASTM), to the stream of molten metal as the stream flows from the ladle to the tundish. This amount oflead shot must be added uniformly while and whenever steel flows from the ladle to the tundish, necessitating a rapid opening and shutting off of the lead stream.
In actual operation, steady line air pressure of 80200 p.s.i. is employed and the diameters of the meter orifices 28. 28. 28". and 28" in metering bar 16 are established in view of the type and size of the material to be used. Where it is desired to add lead particles, it is suggested that there be three meter orifices with diameters of at least 0.500, 0.375 and 0.312
In the subject invention, the air supply to the barrel 14 is normally closed and is only used to clear barrel 14 of particles when required. It is not used to propel the particles. The air supply to airhose 18 and air nozzle 42 is regulated from 0 to p.s.i., as required, with the opening in the nozzle 42 being 0.060 inches. The gap between nozzle 42 and aperture 41 is 0.150 inches. Airhose 18 is a 5/32-inch [.D. plastic tubing in rigid copper conduit.
Air injector line 32' is -inch diameter smooth bore and the orifice in nozzle 33 is 0.020 inch. Air is supplied at steady line pressure.
Air injector line 32' and nozzle 33 intersects the r-onch diameter smooth bore vertical tube at approximately a 45angle. The particles that are motivated by air from nozzle 33 are propelled into conduit 34 and into barrel 14 which is positioned at an angle approximately 1 1 5 from the vertical bore 29 and extending downwardly toward nozzle 36. Barrel 14 is approximately l inch l.D., 9 feet long and of stainless steel.
The entire device is mounted on a tripod base with a 360- ball bearing turntable. Appropriate thumb screws or the like can be used to secure the device on the turntable or to facilitate altering the direction of the flow of material from the device.
The above discussion was made for purposes of illustration only and is not intended as a limitation of the invention. It is understood that others working in the art can make various alterations in the above-described specific embodiment while remaining within the scope of the invention.
1. In a device for adding fine particle-sized solids to a molten metal stream in a continuous casting operation, said device having a hopper with an opening in the bottom wall thereof, said solids being adapted to be stored in said hopper prior to being added to said stream, a barrel located under said hopper through which said solids are adapted to be directed into the stream;
an improvement in said device, said improvement comprisconnecting means for connecting said hopperto said barrel,
said connecting means comprising:
a first conduit having two ends, one of said first conduit ends terminating close to said hopper opening;
said first conduit being positioned in substantially vertical alignment with said opening;
a second conduit having two ends and inclined to said first conduit, one of said second conduit ends terminating as the remaining end of said first conduit and the remaining end of said second conduit terminating at said barrel;
said barrel being inclined downwardly from said connecting means to the free end of said barrel;
restrictive means for controlling the passage of solids through said opening, said restrictive means comprising:
metering means having a plurality of orifices of varying sizes, said metering means located below said hopper opening and contiguous to said hopper end of said first conduit, said metering means having means for selectively placing and maintaining one of said orifices in substantially vertical alignment with said opening in said hopper;
a first fluid injector means located in said hopper, said first injector means having a nozzle positioned adjacent said opening, with said opening in said nozzle being substantially smaller in size than the size of said bottom wall opening;
a second fluid injector means located adjacent an opening in said connecting means; and,
said second fluid injector means having a nozzle means inclined at an acute angle to said connecting means and in a direction away from said hopper.
2. The improvement described in claim 1 wherein said second conduit is in substantial axial alignment with said second fluid injector means.
3. The improvement described in claim 1 comprising:
said barrel communicates with said second conduit and is inclined downwardly towards said stream;
tering means comprises a metering bar located between said bottom wall and said connecting means, said bar having a plurality of orifices of varying sizes located therein and said bar having selector means attached thereto for selectively moving said bar relative to said opening in said wall to position and maintain one of said orifices in substantial alignment with said opening.