US3337138A - Apparatus for discharging particulate material - Google Patents

Description

22, 1967 J. w. BROWN, JR. ETAL 3,337,138

APPARATUS FOR DISCHARGING PARTICULATE MATERIAL 5 Sheets-Sheet Filed Jan. 20, 1964 R s w W wmw w mwwm k ficw d W NWM ME JAF 22, 1967 J. w. BROWN, JR. ETAL 3,337,138

APPARATUS FOR DISCHARGING PARTICULA'I'E] MATERIAL Filed Jan. 20, 1964 5 Sheets-Sheet INVENTOR-S JOHN W 3 W MJE? ARTHUR C. ES/NG 7 BY Bmmok, SW

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HTTGPA/E/J Aug. 22, 1967 J. w. BROWN, JR.. ETAL 3,337,138

APPARATUS FOR DISCHARGING PARTICULATE MATERIAL Filed Jan. 20, 1964 5 Sheets-Sheet 3 INVENTORS JOHN W. BROWN, JR ARTHUR CBUES/N iF/PA/vc/s ThAASER 4 rrapA/zss United States Patent 3,337,138 APPARATUS FOR DISCHARGING PARTICULATE MATERIAL John W. Brown, Jr., Lakewood, Ohio, Arthur C. Buesing, Milwaukee, Wis., and Francis T. Kaiser, Cleveland, Ohio, assignors to Brown Fintube Company, Elyria, Ohio, a corporation of Ohio Filed Jan. 20, 1964, Ser. No. 338,755 Claims. (Cl. 239-345) This invention relates to apparatus for propelling particulate material, and more particularly to apparatus for discharging a stream of particles by means of a propellant or carrier fluid under pressure, which apparatus can be readily adjusted to vary the rate of flow of the particles being discharged.

While apparatus embodying the invention may be employed for various purposes, it will be described hereinafter as employed for injecting solid particulate addition material, such as aluminum particles, into molten metal such as steel. In the preparation of certain metals and metal alloys it is often desired to effect certain chemical or metallurgical reactions between the molten metals and various addition agents. For example, metallic aluminum is often introduced into molten steel for deoxidizing the steel or providing residual aluminum for control of grain structure or alloying. However, addition agents often have such characteristics that it is diflicult thoroughly to intermix them with the moltent metal; for example, they may be considerably lighter as is the case when aluminum is added to steel. Other additives may be diflicult to wet with the molten metal, or may require considerable time for reaction even at high temperatures. In order to overcome these difliculties it has been proposed to inject the finely divided solid addition agents into the molten metal. A preferred method of injection is that disclosed in US. Patent 3,224,051 issued Dec. 21, 1965, on an application filed by I. W. Brown, Jr., A. C. Buesing, and F. T. Kaiser, according to which a particulate addition agent is propelled by a stream of gas such as air into a freely falling stream of molten metal, the particles being propelled with suflicient force to penetrate the molten metal. The apparatus for so propelling and injecting the particles is referred to hereinafter as a gun.

Such a gun should provide a high ratio of addition agent to the propellant fluid and should .be capable of injecting the desired large amount of addition agent during the relatively short pouring time. In modern Steel making practice, several hundred tons of steel may be poured from a furnace into a ladle in a few minutes, and several hundred pounds, and often more than a thousand pounds, of aluminum must be added to the steel before the slag pours into the ladle to achieve the desired results. Consequently, the gun must be capable of injecting a large quantity, often several hundred pounds, of particles per minute into the stream of the molten steel freely falling into the ladle. The discharging stream of particles and propellant fluid should cause the particles to travel in a path that is small in cross section in order to intersect the stream of molten metal without appreciable particle scattering, and should propel the particles with suflicient velocity to cause them to penetrate the heavier molten metal. The proportion of propellant fluid relative to the addition agent particles should be as small as possible to minimize possibility of trapping the particles in bubbles of propellant fluid in the liquid metal.

Furthermore, it is important that the rate of flow of particles from the gun be readily adjustable before and during discharge of particles from the gun. The necessity of injecting the calculated amount of addition agent in the short time permitted for injection during pouring are fac- 3,337,138 Patented Aug. 22, 1967 tors which may necessitate adjustment of the gun before discharge of the particles. Variations in the rate of flow or shape of the stream of pouring metal are factors necessitating rapid adjustment of the rate of discharge of addition agent particles.

It is an object of the invention to provide improved apparatus for satisfying the above requirements and overcoming the above problems. A further object is the provision of apparatus by Which there may be injected into melts, such as molten steel, particles of one or more addition agents such as aluminum. Another object is the provision of particle propelling apparatus that may be rapidly adjusted by a single control to vary .the flow of particles.

Other objects and advantages of the invention will be apparent from the following description of a preferred embodiment, in connection with the accompanying drawings in which:

FIGURE 1 is a perspective view showing an apparatus embodying the invention as used in injecting aluminum articles into a stream of molten steel pouring from an open hearth;

FIGURE 2 is a detail side elevation, generally from line 22 of FIGURE 1, showing the injection of aluminum particles downwardly into the falling stream of molten metal, the conditions at the beginning of the pour being illustrated in full lines and those near the end of the pour by broken lines;

FIGURE 3 is a perspective view, to an enlarged scale, showing the major portion of the apparatus for discharging particles;

FIGURE 4 is an elevation of the portion of the apparatus shown in FIGURE 2, but to a somewhat larger scale, the near wheel and other parts being omitted by show more clearly the propelling portion of the gun, the control valve, and tubes connecting the control valve to the air supply and the main and auxiliary conduits of the FIGURE 5 is a vertical elevation, to a scale considerably larger than that of the preceding figures, of the propelling portion of the gun of FIGURES 1, 2, 3, and

FIGURE 6 is a detail elevation, partially broken away, showing the relationship of the auxiliary conduit to the main passage;

FIGURE 7 is a somewhat diagrammatic sectional elevation through the control valve showing one extreme position of the movable closure member of the valve;

FIGURE 8 is a similar cross section showing an intermediate position of the closure member; and

FIGURE 9 is a similar cross section showing another extreme position of the closure member.

In FIGURE 1 the preferred form of the gun embodying the invention, generally indicated by 1, is shown as standing on a pouring platform 2 along the pouring side of an open hearth furance 3. The furnace has a pouring spout 4 shown as discharging a stream of molten metal 5 in conventional manner from its end into a ladle 6 to form a body 7 of molten steel in the ladle. The gun 1 is shown as discharging particles 8 of metallic aluminum for deoxidizing purposes in a stream 9 that intersects the stream 5. In FIGURES 1 and 2 the particles are shown as being discharged downwardly and substantially vertically into the stream 5 at the location thereof at which it begins to fall substantially vertically, as disclosed and claimed in our US. Patent No. 3,260,591, issued July 12, 1966 on an application filed concurrently herewith.

As shown in FIGURES 3 and 4, gun 1 comprises a supply hopper 11 the upper end of which is open to the atmosphere and hence readily available for filling and inspection. The hopper is designed to contain a weighed 'amount of aluminum particles 8, which may take the form of'the usual button shaped particle about A to /2 inch in diameter and /3 to inch thick. The hopper 11 is fixed to a frame 12 supported by a pair of wheels 13. Frame 12 has handles 14 for guiding the apparatus, and legs 15 to aid in supporting it when it is stationary.

A propelling portion 16 is fixed to the frame below hopper 11; the hopper is preferably tapered downwardly and inwardly to facilitate movement of the particles into the propelling portion. As shown in FIGURES 3 and 4, propelling portion 16 is connected by metal tubes 17 and 18 to a control valve 19 actuated by a valve handle 21. Valve 19, to be described later, controls the rate of flow of propellant fluid through the tubes 17 and 18 to the propelling portion 16 and thereby controls the rate of discharge of particles from the gun. Valve 19 is connected through a conventional shutoff valve 22, operated by handle 23, to a hose 24 supplying a suitable source of propellant fluid under pressure, such as air at about 100 pounds per square inch commonly available in steel plants.

The other end of the propelling portion 16 is connected to the feed end of an elongated barrel 25 (FIGURES 1, 3 and 4). This barrel preferably is a tube of heat resistant metal such as stainless steel of a length such that when its discharge end 26 is in operative location, the hopper 11 and persons working around it are not exposed to excessive heat.

The propelling portion 16 of the gun 1, shown in detail in FIGURES 5 and 6, comprises a body 30 having a laterally extending main internal passage 31 terminating in a discharge end 32 connected to the barrel 25. At its other end the body 30 carries an internally axial-1y projecting nozzle 33 having a bore 34 communicating with air supply tube 17 and discharging into main passage 31. The discharge end 35 of nozzle 33 is adjustably axially located by being threaded in plate 36 closing the end of body 30 and is locked in place by set screws 37 that are threaded in body sleeve 38 and bearing against the outward projection of the nozzle.

'Propelling portion 16 also includes a downwardly extending tubular feed conduit 41 having an internal passage 42 communicating at its upper end with the bottom of hopper 11 and at its lower end with the main passage 31 through the body 30 at a location downstream from the nozzle 33.

To increase the velocity of air discharging from nozzle 33, the walls of the bore 34 at the discharge end of the nozzle are tapered inwardly at 43 to define an orifice 44 of a cross section substantially smaller than bore 34 and much smaller than the cross section of the main passage 31, so that propellant air under pressure traveling through nozzle bore 34 substantially increases in velocity as it passes through the orifice into the larger main passage 31 and travels in an expanding stream indicated diagrammatically by a broken line A in FIGURE 5. Close to orifice 44, the stream has a relatively small cross section and travels at its highest velocity; the Velocity of the stream decreases and its cross section increases with increasing distance from the orifice until the stream cross section approaches that of the passage 31 and the stream velocity is substantially reduced. The pressure in the zone B surrounding the stream A therefore is substantially lower than elsewhere in main passage 31; preferably the parts are so related that the pressure in zone B is less than atmospheric pressure and the opening 42 of feed conduit 41 discharges into this zone. This low pressure zone promotes flow of particles from feed passage 42 into main passage 31, and the entrainment of these particles into the air stream discharged from the nozzle 33 and traveling through the main passage 31 into and through the gun barrel 25. The above described features increase the amount of particles which can be entrained into the air stream and discharged from the gun.

Another feature that greatly increases the quantity of particles drawn into and discharged from the gun is a return conduit generally indicated by 45 through which some of the air from main passage 31 flows into the passage 42 of the particle feed conduit 41 and also preferably into the lower portion of the hopper 11 discharging into conduit 41. Conduit 45 communicates with main passage 31 at a location that is downstream from the orifice 44, the opening of feed passage 42 into passage 31, and the low pressure zone described above, at which location a substantial proportion of the kinetic energy of the air has been transferred to the particles. Conduit 45 has a branch 45a communicating with feed passage 42 substantially above its opening into the main passage 31 and another branch 45b having a downwardly directed discharge end in hopper 11 directly above and close to where hopper 11 enters feed conduit 42. It appears that return conduit 45 also increases the rate in which material can be discharged by the apparatus by removing a portion of the air from main passage 31 after it has acted to entrain particles into the air stream and to impart substantial kinetic energy to the particles; such removal of air apparently provides space for an additional volume of particles to pass through the gun barrel, and also reduces air resistance in the barrel. Furthermore, since the air removed from passage 31 and discharged by branch conduits 45a and 45b into passage 42 of the feed conduit 41 is at superatmospheric pressure, it exerts on the addition agent, particles in and about to enter passage 42 an air pressure tending to urge the particles into the main passage 31; the returned air also agitates the particles in the feed passage, preventing clogging.

The locations at which the conduit branches 45a and 45b discharge into the particle feed passage 42 and hopper 11 should be sutficiently remote from the outlet of passage 42 into main passage 31 to prevent air emanating from the branch conduits from short circuiting downwardly into passage 31 without acting on the particles in passage 42, and sutficiently below the lowest level of particles of the hopper 11 during normal operation to prevent short circuiting upwardly. Branch conduit 45a includes a valve 46 and branch conduit 45b includes a valve 47 to permit adjustment of the flow of air to each of such conduits.

The restricted orifice 44 and the return conduit 45 in combination increase the output of particles discharged from the gun much more than the total effect of these features when used separately.

The illustrated propelling portion 16 also includes an auxiliary conduit 50 having a passage 51 (FIGURE 6) disposed with its axis at a flat angle to the axis of the main passage 31 so that air is discharged downstream from conduit 50 into passage 31 at a location downstream of and relatively close to the opening of passage 42 into main passage 31, but upstream of the opening of return conduit 45 into the main passage 31. Auxiliary conduit 50 includes a plate 52 providing an orifice 53 that is substantially smaller in cross section than the main passage 31 of body portion 30 and preferably of the same size and configuration of orifice 44. Orifice 53 is located close to the opening of passage 51 into the passage 31. Conduit 50 includes an extension 54 shaped to clear other parts of the apparatus and connected by tube 18 to valve 19.

The rate of flow of particles from the gun can be readily controlled by valve 19, which varies the rate of flow of air through the main passage 31 in relation to the flow of air through the auxiliary passage 51. Valve 19 increases the rate of flow through either of the passages 31 or 51 while decreasing the rate of flow of air through the other passages 51 or 31.

As is apparent from FIGURES 4, 7, 8 and 9, the value 19 comprises a body 61 having a conventional bore 62 of cylindrical or frusto-conical shape. The body includes bosses 63, 64 and 65 respectively having ports 66, 67 and 68. Boss 63 is connected by pipe 69 to shutoff valve 22 connected to main air supply line 24, so that port 66 is connected to the air supply. Boss 64 is connected by pipe 17 to nozzle 33, so that port 67 thus communicates with the main passage 31 through orifice 44. Boss 65 is connected to air tube 18 that is connected to the auxiliary conduit 50, so that port 68 communicates with orifice 53 and auxiliary passage 51.

The valve 19 also includes a turnable member 71 having a curved outer surface 72 that fits closely into bore 62 of body 61, and a hollow interior 73- communicating with ports 74 and 75 of member '71. Ports 74 and 75 are so located relatively to each other and to the fixed body ports 66, 67 and 68 to permit the desired control of the flow of air through ports 67 and 68.

Thus, as shown in FIGURE 7, turnable member 71 is so positioned that it completely closes body port 68 while completely opening through port 74 body port 67 communicating with the main passage 31, so that all air from port 66 can pass through port 67 and into the main passage 31 to cause maximum rate of flow of air past the lower end of particle supply passage 42 to entrain and propel particles at the maximum rate.

In FIGURE 8, the member 71 is so turned that the air supply body port 66 is completely open, but the body port 67 that communicates with the main passage 31 and port 68 that communicates with the auxiliary conduit 51 are only approximately half open. When the valve is in this position, part of the air supplied through port 66 passes through port 67 while the remainder passes through port 68, and the rate of flow of particles from the apparatus is reduced substantially below that when the valve is set as in FIGURE 7.

When member 71 is turned to the position shown in FIGURE 9, body port 67 communicating with main passage 31 is completely closed, while port 68 communicating with the auxiliary passage 51 is completely open and all of the air supplied through port 66 thus travels through auxiliary passage 51. The flow of particles from the gun is at a minimum for the particular design. The particle flow can, of course, be entirely halted by stopping the flow of air by valve 22.

As shown in FIGURE 4, the valve 19 has a control handle 21 that also indicates the position of the turnable member 71 by a pointed end 76 that moves parallel to an indicator dial 77 fixed to the frame of the apparatus and carrying indicia marks 78, 79 and 80. When the handle is turned so its end 76 points to mark 78, the valve 19 is as shown in FIGURE 7; when the handle points to central mark 79, the valve is as shown in FIGURE 8; and when the handle is turned so it points to mark 80, the valve is as shown in FIGURE 9. Of course, when the valve member 71 is turned between the positions shown in FIG- URES 7 and 8, and between the positions shown in FIG- URES 8 and 9, the flow of particles is correspondingly reduced.

The apparatus may be designed so that the flow of particles may correspond to calibrated marks on the dial 77; it may also be proportional to the angular position of member 71. The valve may be converted from a standard three-way, two port valve by modifying the turnable member 71 of the standard valve to have ports similar to ports 74 and 75.

The apparatus thus makes it possible to achieve the desiderata previously set forth, and in particular makes it possible readily and accurately to vary and adjust the flow of additional agent particles from the gun, by means of a single control which can be easily manipulated. The apparatus can be of simple, rugged and economical construction. It is simple in operation and provides a wide desired range of adjustments for handling various types and kinds of particulate material at widely variable, closely controlled rates of flow.

Those skilled in the art will appreciate that various changes and modifications can be made in the apparatus described herein by Way of example, without departing from the spirit or scope of the invention. The essential characteristics of the invention are defined in the appended claims.

We claim:

1. Gun apparatus for discharging particulate material, comprising a body having an elongated passage extending toward a discharge opening therein, an opening for feeding particulate material opening laterally into said passage and adapted to communicate with a supply of particulate material, first orifice means adapted to discharge propellant fluid under pressure into said passage, said first orifice means being located upstream of said feed con duit means opening and adapted to discharge propellant fluid in a downstream direction, second orifice means adapted to discharge propellant fluid under pressure into said passage, said second orifice means being located downstream of said feed opening and adapted to discharge propellant fluid in a downstream direction, a source of propellant fluid under pressure, and valve means communicating with said source of propellant fluid and with both said orifice means, said valve means being adjustable to vary the volume flowing through each of said first and second orifice means of propellant fluid reaching said valve means from said source.

2. The apparatus of claim 1 in which said valve means is adjustable to increase the flow of fluid through one of said orifice means while decreasing the flow of fluid through the other.

3. The apparatus of claim 1 in which said first orifice I means has a cross sectional area substantially smaller than that of said passage.

4. The apparatus of claim 1 in which said second orifice means has a cross sectional area substantially smaller than that of said passage.

5. Gun apparatus for discharging particulate material, comprising a body having an elongated passage extending toward a discharge opening therein, feed conduit means for feeding particulate material opening laterally into said passage and adapted to communicate with a supply of particulate material, first orifice means adapted to discharge propellant fluid under pressure into said passage, said first orifice means being located upstream of said feed conduit means opening and adapted to discharge propellant fluid in a downstream direction, return conduit means one end of which opens into said feed conduit means and the other end of which opens into said passage at a location downstream from said first orifice means and from said feed conduit means opening, second orifice means adapted to discharge propellant fluid under pressure into said passage, said second orifice means being located downstream of said feed conduit means opening and adapted to discharge propellant fluid in a downstream direction, a source of propellant fluid under pressure, and valve means communicating with said source of propellant fluid and with both of said orifice means, said valve means being adjustable to vary the volume flowing through each of said first and second orifice means of propellant fluid reaching said valve means from said source.

6. The apparatus of claim 5 in which said return conduit means opens into said passage at a location downstream from said second orifice means.

7. The apparatus of claim 5 in which said valve means is adjustable to increase the flow of fluid through one of said orifice means While decreasing the flow of fluid through the other.

8. Gun apparatus for discharging particulate material, comprising a body having an elongated passage extending toward a discharge opening therein, feed conduit means for feeding particulate material opening laterally into said passage and adapted to communicate with a supply of particulate material, first orifice means adapted and located to discharge propellant fluid under pressure in a downstream direction into said passage from a location upstream of said feed conduit means opening, return conduit means having one end opening into said feed conduit means and its other end opening into said passage of said body at a location downstream from said location of said orifice means and from said feed conduit means opening, second orifice means adapted and located to discharge propellant fluid under pressure in a downstream direction into said passage from a location downstream from said first orifice means and from said feed conduit means opening, and means for supplying propellant fluid under pressure to both of said orifice means.

9. The apparatus of claim 8 in which said feed conduit means comprises hopper means and a second passage communicating with said hopper means and said first mentioned passage at said feed conduit means opening, and in which said return conduit means comprises two conduits, one of which opens into said hopper means and the other of which opens into said second passage.

10. The apparatus of claim 9 comprising-a source of propellant fluid under pressure, and valve means communicating with said source of propellant fluid and with both of said orifice means, said valve means being adjustable to vary the volume flowing through each of said first and second orifice means of propellant fluid reaching said valve means from said source.

References Cited UNITED STATES PATENTS EVERETT W. KIRBY, Primary Examiner.

Claims (1)

1. 8.GUN APPARTUS FOR DISCHARGING PARTICULATE MATERIAL, COMPRISING A BODY HAVING AN ELONGATED PASSAGE EXTENDING TOWARD A DISCHARGE OPENING THEREIN, FEED CONDUIT MEANS FOR FEEDING PARTICULATE MATERIAL OPENING LATERALLY INTO SAID PASSAGE AND ADAPTED TO COMMUNICATE WITH A SUPPLY OF PARTICULATE MATERIAL, FIRST ORIFICE MEANS ADAPTED AND LOCATED TO DISCHARGE PROPELLANT FLUID UNDER PRESSURE IN A DOWNSTREAM DIRECTION INTO SAID PASSAGE FROM A LOCATION UPSTREAM OF SAID FEED CONDUIT MEANS OPENING INTO SAID FEED CONDUIT MEANS HAVING ONE END OPENING INTO SAID FEED CONDUIT MEANS AND ITS OTHER END OPENING INTO SAID PASSAGE OF SAID BODY AT A LOCATION DOWNSTREAM FROM SAID LOCATION OF SAID ORIFICE MEANS AND FROM SAID FEED CONDUIT MEANS OPENING, SECOND ORIFICE MEANS ADAPTED AND LOCATED TO DISCHARGE PROPELLANT FLUID UNDER PRESSURE IN A DOWNSTREAM DIRECTION INTO SAID PASSAGE FROM A LOCATION DOWNSTREAM FROM SAID FIRST ORIFICE MEANS AND FROM SAID FEED CONDUIT MEANS OPENING, AND MEANS FOR SUPPLYING PROPELLANT FLUID UNDER PRESSURE TO BOTH OF SAID ORIFICE MEANS.

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