Metal chip furnace charge apparatus and method

Apparatus and method for charging metal chips into a molten bath of the metal from which the chips are formed, comprising a compacting extruder and a delivery conduit which is resistant to the mass of molten metal and which is pivotable to dip into the molten metal bath when chips are being charged thereinto and out of contact with the bath when charging is to be discontinued, are disclosed. The chips are forced through the delivery conduit in the form of a compacted or densified mass preferably having a density between about 30 and 60 percent of the density of the solid metal and preferably between about 55 and 80 pounds per cubic foot. Feed is continued while the delivery conduit is in the molten metal bath and until it is removed therefrom to prevent entry of molten metal into the delivery conduit. The method is preferably conducted on a continuous basis and various sensors with appropriate wiring may be employed for safety and for making the method substantially automatic in operation.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
Utilization of metal chips, especially scrap metal chips, particularly 
brass and aluminum. Introduction of said metal chips into a molten mass of 
metal of which they are formed and below the surface thereof. Maintaining 
a densified mass of compacted chips at an optimum density and maintaining 
the rate of chip introduction into the molten metal mass at an optimum 
level and apparatus for so doing. 
2. Prior Art 
The situation has been fully reviewed in my prior U.S. Pat. No. 4,702,768, 
upon which the present method and apparatus are improvements. Reference is 
made to that U.S. patent, issued Oct. 27, 1987, and the disclosure thereof 
is incorporated herein by reference as fully as though it were set forth 
herein. It is a part of the prior art relevant to the present invention 
and the most relevant prior art of which I am aware. 
In my prior patent, a method of compacting and extruding metal chips into 
the form of a solid stripform or rope, from a briquetter or compacting 
extruder or the like, for the convenient and controlled introduction 
thereof into a mass of molten metal of which the chips were formed at a 
point below the surface thereof, and apparatus for so doing, was 
disclosed. The object was to reduce undesirable oxidation of the chips and 
of the mass of molten metal into which introduced, and to obtain more 
efficient and economical control over the procedure of rapidly melting the 
starting chips into a mass of molten metal in a reverberatory furnace or 
the like, a paramount objective being the provision of a more satisfactory 
method whereby metal chips, especially scrap metal chips, could be 
reintroduced into the stream of commerce in the form of new metal. 
Although the method and apparatus of my prior patent went far toward 
alleviating the problems previously existing in the art, it has now been 
found that still additional improvements and advantages can be effected. 
Such improvements in the method and in the apparatus are the subject 
matter of the present patent application. 
OBJECTS OF THE INVENTION 
It is an object of the present invention to provide an improved method for 
the introduction of starting metal chips into a mass of molten metal of 
which they are formed, and apparatus for so doing. Another object is the 
provision of such method and apparatus wherein the chips are not 
introduced into the molten metal mass in the form of a solid metal rope or 
chain of briquettes or the like, but rather in the form of a 
compacted-extruded densified mass of chips, preferably having a 
predetermined weight and a predetermined density, both by way of pounds 
per cubic foot and by way of percentage of the density of the solid metal 
itself. An additional object is the provision of such a method and 
apparatus for conducting the same wherein compacted metal chips are forced 
into and along a suitable delivery conduit in the form of a compacted or 
densified mass which substantially fills the delivery conduit, and 
preferably having the aforementioned characteristics, until the mass of 
compacted chips bursts forth from the exit end or port of the delivery 
conduit below the surface of the mass of molten metal in the form of 
dissipated or dissociated chips, which readily and substantially 
immediately melt into the mass of molten metal below the surface thereof 
without loss of substantial amounts of metal by virtue of oxidation during 
the process. A still further object of the invention is the provision of 
such a method involving relatively economical compactor-extruder means and 
wherein the compacted and extruded chips proceed in the form of a 
densified mass into and along a delivery conduit until they exit into the 
mass of molten metal beneath the surface thereof, wherein a sufficient 
pressure is maintained upon the mass of chips within the delivery conduit 
at all times sufficient to prevent substantial entry of the mass of molten 
metal into the delivery conduit, and such a method which may be conducted 
on a continuous, semicontinuous, or batchwise basis, as desired, and 
wherein the delivery conduit or the entire chip-charge unit of the 
invention may be lowered into or elevated out of contact with the mass of 
molten metal, preferably but not necessarily by pivoting the same. A still 
further object of the invention is to provision of such a method and 
apparatus for the practice thereof wherein the pressure upon and feed of 
compacted-extruded chips in the form of the densified mass is maintained 
in the delivery conduit until the delivery conduit is elevated out of 
contact with the mass of molten metal. Still an additional object of the 
invention is the provision of such a method and apparatus for the practice 
thereof wherein numerous sensors with associated circuitry or wiring are 
provided for purposes of safety and for making the method substantially 
automatic in operation, if desired. Still further objects will become 
apparent hereinafter and still additional objects will be apparent to one 
skilled in the art to which this invention pertains. 
SUMMARY OF THE INVENTION 
The invention, then, comprises the following aspects, inter alia, alone or 
in combination: 
A method for the industrial utilization of metal chips which involves the 
introduction of said metal chips into a mass of molten metal of which said 
chips are formed, comprising the steps of: 
providing a delivery conduit of a material which is resistant to the mass 
of molten metal, under the temperature and other conditions present 
therein, 
compacting and extruding said metal chips into said delivery conduit in the 
form of a densified mass, 
creating a pressure upon the mass of chips in the delivery conduit, 
causing the mass of chips in the delivery conduit to substantially fill 
said delivery conduit and to move along said delivery conduit, 
causing said delivery conduit to dip into said mass of molten metal so as 
to provide a point of introduction below the surface thereof, 
causing the mass of chips within the delivery conduit to exit from said 
delivery conduit directly into said mass of molten metal at said point of 
introduction below the surface thereof, and 
maintaining a pressure upon the mass of chips within the delivery conduit 
sufficient to prevent substantial entry of the mass of molten metal into 
said delivery conduit; such a 
method which is conducted on a continuous basis; such a 
method which is conducted on a semicontinuous or batchwise basis; such a 
method wherein said delivery conduit is elevated out of said mass of molten 
metal when it is desired to discontinue the introduction of chips 
thereinto; such a 
method wherein said delivery conduit is alternately dipped into and removed 
from said mass of molten metal; such a 
method comprising the step of alternately pivoting the delivery conduit to 
a position dipping into said mass of molten metal and to a position 
removed from said mass of molten metal; such a 
method wherein the process is carried out on a continuous basis until it is 
desired to discontinue introduction of the densified mass of chips into 
the molten mass of metal, whereupon said delivery conduit is elevated out 
of a position dipping into said mass of molten metal and the pressure upon 
the mass of chips in the delivery conduit is reduced or discontinued; such 
a 
method including the step of providing supply means for chips ahead of said 
compaction and extrusion steps and sensing the presence of starting chips 
in said supply means and discontinuing the introduction of the mass of 
chips into the molten mass of metal when the quantity of starting chips 
falls below a predetermined minimum; such a 
method wherein, as a part of said discontinuance, said delivery conduit is 
pivoted to a position removed from said mass of molten metal; such a 
method including the step of providing supply means ahead of said 
compaction and extrusion steps and sensing the presence of starting chips 
in said supply means and commencing the introduction of the densified mass 
of chips into the molten metal when the quantity of starting chips is 
above a predetermined minimum; such a 
method wherein, as a part of the discontinuance of said introduction, the 
delivery conduit is pivoted from a position dipping into said mass of 
molten metal to a position removed from said mass of molten metal; such a 
method wherein the chips are compacted to a point within the range of 
approximately 55 to 80 pounds per cubic foot during the extrusion process; 
such a 
method wherein the chips are compacted to approximately 65-70 pounds per 
cubic foot during the extrusion process; such a 
method wherein the density of the mass of chips within the delivery conduit 
is maintained between about 30 and 60 percent of the density of the solid 
metal; such a 
method wherein the density of the mass of chips within the delivery conduit 
is maintained between about 40 and 50 percent of the density of the solid 
metal; such a 
method wherein the density of the mass of chips within the delivery conduit 
is maintained at approximately 42 percent of the density of the solid 
metal; such a 
method wherein the starting material comprises aluminum chips and the bath 
of molten metal is molten aluminum; such a 
method wherein an inert gas is introduced into the delivery conduit along 
with the mass of chips for the displacement of oxygen therein; such a 
method wherein said delivery conduit is removed from the mass of molten 
metal before discontinuing feed of the densified mass of chips to said 
delivery conduit; and such a 
method including the step of sensing the presence of starting metal chips 
in supply means located ahead of said compaction and extrusion steps and 
discontinuing delivery of starting metal chips to said supply means when 
the quantity of metal chips therein exceeds a predetermined maximum. 
Moreover, an apparatus for the introduction of metal chips into a mass of 
molten metal of which said chips are formed, the combination comprising: 
compactor and extruder means for compaction and extrusion of compacted 
metal chips into a delivery conduit in the form of a densified mass, 
a delivery conduit of material resistant to the mass of molten metal under 
the temperature and other conditions present therein, 
wherein said delivery conduit has one open end for communicating with said 
mass of molten metal and an opposite open end in communication with said 
extruder means, 
means for providing a pressure upon the mass of chips within said delivery 
conduit, and for moving said mass of chips along said delivery conduit, 
and out of said one open end thereof and into said mass of molten metal 
when said delivery conduit is positioned so as to dip below the surface of 
said mass of molten metal; such a 
combination comprising a metal chip charge box for introduction of starting 
metal chips into said compactor and extruder means; such a 
combination including hopper means associated with said charge box for 
delivery of starting metal chips thereinto; such a 
combination comprising elevating and lowering means for lowering said 
delivery conduit into a position dipping into said mass of molten metal 
and elevating said delivery conduit into a position removed from said mass 
of molten metal; such a 
combination wherein the means operating both to extrude said chips in the 
form of a densified mass into said delivery conduit and to provide 
pressure upon the mass of chips in said delivery conduit is a 
compactor-extruder; such a 
combination wherein said compactor and extruder means is a screw-compacting 
extruder; such a 
combination including supply means for bringing said starting material 
chips to the compactor and extruder; such a 
combination including sensing means associated with said supply means for 
discontinuing feed of the mass of chips into said molten metal mass when 
the supply of starting metal chips falls below a predetermined minimum; 
such a 
combination including elevating means for elevating said delivery conduit 
out of said molten metal bath and wherein said sensing means is also 
associated with said elevating means; such a 
combination including metal chip supply means for bringing metal chips to 
the extruder and compactor and sensing means for discontinuing supply of 
metal chips when the quantity of starting metal chips in said supply means 
is above a predetermined maximum; such a 
combination including metal chip supply means for bringing metal chips to 
the extruder and compactor and pivot means and sensing means for pivoting 
said delivery conduit out of contact with said molten metal bath when the 
quantity of metal chips in said supply means falls below a predetermined 
minimum; such a 
combination including means for the introduction of an inert gas into said 
delivery conduit along with the compacted or densified mass of chips; such 
a 
combination including elevating and lowering means for elevating and 
lowering said delivery conduit into contact with and out of contact with 
said mass of molten metal and sensing means for sensing the supply of 
starting metal chips and initiating feed of chips to said compactor and 
extruder and into said delivery conduit when said supply of starting chips 
is above a predetermined minimum but for elevating said delivery conduit 
out of contact with said molten metal bath and discontinuing feed when 
said supply of starting metal chips falls below a predetermined minimum; 
such a 
combination comprising sensing means for sensing a minimum supply of 
starting metal chips located ahead of said compactor and extruder and for 
removing the delivery conduit from the molten metal bath when the supply 
of starting metal chips falls below such a minimum; and such a 
combination including means for pivoting said delivery conduit into and out 
of contact with said molten metal bath, and sensing means for pivoting 
said delivery conduit out of contact with said molten metal bath before 
discontinuing feed of starting metal chips to said compactor and extruder 
means, and means for sensing the minimum supply of starting chips below 
which feed is discontinued. 
Further, an apparatus for the introduction of metal chips into a mass of 
molten metal of which said chips are formed, the combination comprising: 
compactor and extruder means for compaction and extrusion of compacted 
metal chips into said delivery conduit in the form of a densified mass, 
a delivery conduit of material resistant to the mass of molten metal under 
the temperature and other conditions present therein, wherein said 
delivery conduit has one open end for communicating with said mass of 
molten metal and an opposite open end in communication with said extruder 
means, 
means for providing a pressure upon the mass of chips within said delivery 
conduit, and for moving said mass of chips along said delivery conduit, 
and out of said one open end thereof and into said mass of molten metal 
when said delivery conduit is positioned so as to dip below the surface of 
said mass of molten metal, 
and pivot means for pivoting said combination into a position in which said 
delivery conduit is dipping into said mass of molten metal and into a 
position wherein said delivery conduit is removed from said mass of molten 
mass; such a 
combination comprising a metal chip charge box for introduction of starting 
metal chips into said compactor and extruder means, and wherein said 
charge box pivots along with said combination; and such a 
combination including hopper means associated with said charge box for 
delivery of starting metal chips thereinto and wherein said hopper pivots 
along with said charge box. 
Moreover, such a method including the step of coordinating the rate of feed 
of said compacted chips into said mass of molten metal with the 
temperature in said mass of molten metal at or near the point of 
introduction of said compacted metal chips thereinto and such a method 
wherein the rate of introduction of said compacted chips into said mass of 
molten metal is reduced or stopped when said temperature in said molten 
metal mass at or near said point of introduction falls below a 
predetermined temperature. 
Additionally, such a combination comprising sensing means for sensing the 
temperature in a mass of molten metal and control means for coordinating 
the rate of exit of said compacted metal chips from said delivery conduit 
with the temperature sensed in said molten metal mass, and such a 
combination wherein said sensing means comprises a thermocouple. 
Finally, such a combination comprising sensing means for sensing the 
temperature in a mass of molten metal and control means for removing said 
delivery conduit from or lowering said delivery conduit into said mass of 
molten metal depending upon the temperature sensed in said molten metal 
mass, and such a combination wherein said sensing means comprises a 
thermocouple. 
GENERAL DESCRIPTION OF THE INVENTION 
The invention comprises an improved method for the introduction of metal 
chips into a metal bath of which the chips are made, the said method 
enabling the employment of much more economic apparatus then previously 
utilizable, involving a compacting extruder with appropriate means for 
compacting and appropriate means for extruding, and a delivery conduit 
which is elevatable, retractable, or pivotal out of contact with a mass of 
molten metal and lowerable, extendable, or pivotable for dipping beneath 
the surface thereof and constructed of suitable material which is 
resistant to the temperature and other conditions existing in the said 
mass of molten metal. A unique aspect of the method of the invention is 
that the chips are not introduced into the mass of molten metal in the 
form of a solid chain of briquetted metal or a solid rope or the like, but 
rather in the form of a compacted mass which is preferably compacted to a 
density which is approximately 55 to 80 pounds per cubic foot, preferably 
approximately 65 to 70 pounds per cubic foot, and usually between about 30 
and 60 percent of the density of the solid metal itself, preferably 
between about 40 and 50 percent of the density of the solid metal itself 
and, particularly for aluminum chips, with approximately 42 percent of the 
density of the solid metal appearing to be optimum. With such densities of 
the compacted chips, a densified mass is produced which can be made 
substantially to fill the delivery conduit and a sufficient pressure may 
be exerted thereon and maintained for this purpose and for purposes of 
causing the mass of chips to move along the delivery conduit and to enter 
into the mass of molten metal at the exit port of said delivery conduit 
below the surface of the mass of molten metal. With the employment of such 
conditions, especially of the compacted chips being in the form of a 
densified mass, much less expensive equipment can be utilized for the 
compaction-extrusion aspect of the process since the compactor-extruder 
can be provided in the form of a helical screw-compacting extruder with 
little if any sacrifice of the high performance advantages attained 
according to the prior art with much more expensive equipment, and with 
the further advantage that, when operating according to the method and 
utilizing apparatus of the present invention, the densified mass of chips 
having the prescribed density is being virtually exploded beneath the 
surface of the molten metal mass in the form of disbursed or dissociated 
chips which readily and substantially immediately melt into the mass of 
molten metal into which introduced. An additional aspect of the invention 
includes the introduction of an inert gas into the compacted chips to 
eliminate oxygen and oxidation thereof as they are subjected to pressure 
to cause them to move as a densified mass along the delivery conduit and 
into the mass of molten metal at the exit port thereof. A further 
advantageous aspect of the present invention permits the introduction of 
the delivery conduit into a mass of molten metal or the removal therefrom 
by the employment of suitable introduction and removal means, preferably 
but not necessarily in the form of a pivot arrangement whereby the entire 
chip charging apparatus may be pivoted for location of the delivery 
conduit out of contact with the mass of molten metal or dipping thereinto 
with its exit port below the surface thereof. By the provision of suitable 
sensors, probes, and thermocouples, the entire operation is rendered 
fail-safe so that, if the temperature adjacent the exit port of the 
delivery conduit in the mass of molten metal falls below a predetermined 
minimum, the delivery conduit or the entire chip-charging apparatus may be 
pivoted or otherwise elevated out of contact with the mass of molten metal 
so that the mass of molten metal does not freeze in or around the said 
delivery conduit exit port. Additionally, the method and apparatus may 
advantageously be so conducted and arranged that, whenever feed of chips 
along the delivery conduit and into the mass of moltent metal is desired 
to be discontinued, the delivery conduit is first elevated out of contact 
with the molten metal bath, so that the molten metal does not 
substantially enter into the delivery conduit, and feed of chips only then 
discontinued. As additional aspects of the invention, the commencement of 
the operation and discontinuance thereof can be made dependent upon the 
sensing of an adequate or conversely inadequate supply of chips in chip 
supply means, additional metal chips from a chip source can be ordered by 
sensor means in the supply means once the chip level therein has fallen 
below a predetermined minimum and, all in all, very substantial 
improvement and advantage over any known prior art method or apparatus are 
effected by the employment of the method and apparatus of the present 
invention, as will be immediately apparent to one skilled in the art.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings, and particularly to FIGS. 1 and 3 thereof: 
A conventional reverberatory furnace well is shown generally at 100, 
comprising bottom wall 101 and side walls 102 and 103, with a mass of 
molten metal, preferably and usually aluminum, therein being shown at 104. 
Mounted on side wall 102 of the furnace well is the metal chip furnace 
charge unit of the invention, shown generally at 10. Starting metal chips 
11a brought from chip source CS, shown in the form of an infeed conveyor, 
the drive mechanism of which is connected to electrical controls EC by 
circuitry C1, are present in chip charger supply means comprising infeed 
chute 12, associated with infeed hopper 14 and leading into infeed or 
charge box 15. Starting metal chips 11a therein are sensed (or not 
sensed--13c) in the infeed chute by sensors 13a, 13b, and 13c, 
respectively for stop chip feed delivery, commence chip feed delivery 
and/or proceed with furnace charge, and for stop furnace charger 
operations and remove delivery conduit (21) from furnace well, all 
connected with electrical controls EC by circuitry C2, which controls are 
in turn connected to actuatable elements of the apparatus and system by 
circuitry C3, C4, and C5, as will be more fully explained hereinafter. In 
molten metal mass 104 adjacent the exit port of delivery conduit 21 is 
located a further sensor in the form of thermocouple 13d encapsulated in 
liquid-tight graphite tube 13e connected with electrical controls EC by 
circuitry C6. 
Incoming chips 11a proceed from the infeed chute 12 into hopper 14 where 
they reside as loosely-packed chips 11b. During the process of the 
invention, these chips become compacted chips 11c and then finally, upon 
eruption below the surface of the mass of molten metal 104 in the furnace, 
they become uncompacted chips 11d, again as will be explained further 
hereinafter. 
Further elements of charge unit 10 which are visible in FIGS. 1 and 3 
include bearing housing 22, motor 30 for the screw auger drive unit, base 
38, support stand 41, pivot sleeve 39 mounted on base 38, pivot shaft 40 
mounted on support stand 41, and pivot actuating pneumatic or hydraulic 
cylinder 42 and its associated air or other fluid inlet 42B and shaft 42A 
between support stand 41 and base 38 for pivoting the charge unit 10 about 
its pivot point 39/40 to cause dipping of delivery conduit 21, which is 
constructed of material which is resistant to the mass of molten metal 
under the temperature and other conditions present therein, such as 
graphite, silica, silicon carbide, or ceramic, and which may 
illustratively have an I.D. (internal diameter) of 2 to 5 inches and which 
representatively has an I.D. of 3 inches and is 3 feet in length, into 
molten metal bath 104 or removal therefrom as shown in shadow lines at 
21a. Ahead of delivery conduit 21 is die holder 18 for holding a 
replaceable die 19, to be described further hereinafter and, on the 
opposite side, inert gas injection port 43 is visible. The compactor and 
extruder mechanism is present at 55, just below the charge box 15. Motor 
30 and bearing housing 22 are as shown connected by drive cover 20A. 
Actuating cylinder 42 is pneumatically or hydraulically operated with fluid 
through fluid inlet 42B from a source not shown and screw auger drive 
motor 30, as well as feeder motor 31, are electrically powered from sorces 
not shown but controlled by electrical controls EC via circuitry C4 and 
C3, respectively. 
In FIG. 2 the furnace walls 102, defining the furnace charge well with the 
mass of molten metal 104 therein, are visible with the chip-charging 
apparatus 10 mounted upon wall 102, infeed chute 12 with incoming chips 
11a therein, as well as infeed hopper 14, a portion of the delivery 
conduit extending over the furnace well containing the mass of molten 
metal 104 with its usual metal oxide top skin, screw auger drive motor 30, 
feeder dirve motor 31, drive covers 20A and 34A, and sensor 31a. 
In the cross section of FIG. 3, taken along line 3--3 of FIG. 2, can be 
seen the interior elements of the chip-charging apparatus 10 of the 
invention in enlarged detail. In this FIG. 3, the chip charger device 10 
of the invention is shown with delivery conduit 21 introduced into the 
metal bath, i.e., the charger is pivoted so as to locate the delivery 
conduit 21 in a position dipping below the metal oxide skin floating on 
the top surface of the molten metal bath 104, rather than withdrawn 
therefrom (or pivoted out of contact therewith) as shown in shadow lines 
at 21a in FIG. 1. 
As pointed out with regard to FIG. 1, the delivery conduit 21 and the 
entire chip charger unit 10, for that matter, may be pivoted to take 
conduit 21 out of contact with the mass of molten metal 104 when desired 
and under preselected circumstances, which will be further detailed 
hereinafter, but the delivery conduit 21 means may be raised, retracted, 
or otherwise elevated out of contact with the mass of molten metal 104 and 
alternately lowered therein by various means including a hoist, a 
retractable delivery conduit, an elevator of appropriate size, or the 
like, although it is to be understood that the pivot means illustrated in 
the drawings and otherwise referred to and discussed herein is the 
preferred means of elevating and lowering delivery conduit 21 into the 
mass of molten metal 104, which is, according to the present invention, 
preferably effected by pivoting the same along with the entire charger 
combination or assembly 10 for these purposes as well as for the 
overriding purposes of commencing or discontinuing a particular 
chip-charging operation. 
As shown in FIG. 3, loosely-packed chips 11b proceed in infeed hopper 14 
and are fed into infeed or charge box 15 by feeder fingers 16 mounted on 
feeder shaft 37 driven by chain 34 carried on driven sprocket 36 (See FIG. 
5) and drive sprocket 33 controlled by gear reducer 32 in turn driven by 
feeder drive motor 31, the gear reducer 32 being mounted within base 38 
and motor 31 extending from base 38 and being supported thereby. 
As loosely-packed chips 11b are propelled by rotating feeder fingers 16 
into contact with feed screw auger 17, they are further compacted and 
extruded into delivery conduit 21 in the form of a densified mass 
comprising the compacted chips 11c which substantially fill the delivery 
conduit 21 and are caused to move therealong by the force imparted by the 
compaction/extrusion means 55 until they burst from the open end thereof 
beneath the surface of molten metal mass 104 as dispersed and dissipated 
chips 11d. Conduit 21 has its opposite end communicating with the 
compactor and extruder section of the chip charger apparatus 10, which 
includes venturi 19C leading into replaceable die 19 in the form of a 
rifled barrel-like insert which is held by die holder 18 along with key 20 
for keying the die and die holder elements together, and including inert 
gas injector port 43 for the injection of inert gas into the mass of 
compacted chips 11c for the elimination of oxygen therefrom and for the 
prevention of oxidation during the compacting and extrusion step of the 
operation and especially during travel of chips 11c along conduit 21 into 
molten metal mass 104. 
Feed screw auger 17 is mounted in driven shaft 26 associated with driven 
sheave 27 which is driven by belts 28 connecting with a sheave or pulley 
(not shown) provided on the shaft of screw aueer drive motor 30 beneath 
drive cover 20A as shown in FIG. 1. Driven shaft 26 is mounted in bearing 
housing 22 and supported therein for rotation by tapered roller bearings 
24 and ball bearings 23 sealed in said bearing housing 22 by seals 25, 
said bearing housing 22 as shown being affixed by welding or the like to 
infeed or charge box 15. 
FIG. 4 is a cross-sectional view taken along the line 4--4 of FIG. 3 and 
shows in enlarged detail the inert gas injector port 43 along with key 20, 
keying replaceable die 19 into die holder 18. Replaceable die 19, 
constructed of stress-proof metal such as heat-treated steel, high 
magnesium steel, or the like, has an orifice 19A comprising rifling or 
rifled lining 19B through which the compacted chips 11c are forced under 
pressure by rotation of the feed screw auger 17. 
In FIG. 5 is shown a cross section taken along line 5--5 in FIG. 3, from 
which a portion of infeed hopper 14, infeed or charge box 15, and feed 
screw auger 17 are visible. Feeder fingers 16 located upon feeder shaft 37 
keyed to driven sprocket 36 and mounted for rotation in bearings 35 are 
also visible. It will be apparent that driven sprocket 36 is driven by 
chain or belt 34 and drive sprocket 33 as shown in FIG. 3. 
With respect to sensors 13a, 13b, 13c and 13d, and their connections with 
the electrical controls EC by means of conduitry C2 and C6, as well as 
connection of chip source CS with electrical controls EC by means of 
conduitry C1, which electrical controls are in turn associated with feeder 
drive motor 31, screw auger drive motor 30, and pivot actuating cylinder 
42, respectively by conduitry C3, C4, and C5, these may be connected in 
usual manner with switches and/or rheostats for commencing or 
discontinuing feed into the charge well or otherwise or for varying the 
rate of feed into the charge well or otherwise, depending upon the supply 
of chips sensed, and depending upon the temperature sensed in the mass of 
molten metal in the charge well (when the feed is into the charge well), 
the associated controls for such functions not being illustrated in the 
drawings, but being present in the electrical controls EC provided in the 
system. Aside from an override on and off switch on the electrical control 
box, or an "elevate" and "lower" switch with respect to the delivery 
conduit 21, and other overriding controls which might be desired, the 
apparatus of the invention operates in accord with the method of the 
invention or can be made to so operate almost entirely automatically by 
means of the various sensors employed and their association mainly with 
start-stop sequences as will be even more fully described hereinafter. 
OPERATION 
In operation, starting chips are brought from a chip source CS, as shown in 
the form of an infeed conveyor, and are introduced into infeed chute 12 
until sensor 13a toward the top of chute 12 is reached, whereupon the 
electrical controls and associated circuitry C1 and C2 stop chip feed 
delivery from chip source CS, here illustrated as an infeed conveyor. When 
the supply of chips in the infeed chute 12 reaches sensor 13b, a commence 
chip delivery switch may be thrown, whereupon chip feed delivery commences 
once more from chip source CS. Sensor 13b may also instigate a "proceed 
with charge" command, with activation of the electrical controls via 
circuitry C2, C3, C4, and C5, whereby the charge unit 10 can be pivoted 
into position with its delivery conduit 21 dipping under the surface of 
molten metal pool 104, preferably just after feeder powder and auger power 
have been simultaneously imparted to auger drive motor 30 and feeder drive 
motor 31 for commencement of the compacting-extruding and feeding 
operation into delivery conduit 21. When the charge of starting chips 
drops down below sensor 13c in chute 12, the reverse order of switches is 
thrown and the chip charger unit 10 pivoted so that its delivery conduit 
21 no longer dips beneath the surface of the molten metal mass 104 but is 
removed therefrom as shown in shadow lines in FIG. 1 whereafter the 
operation is stopped. 
As already stated, override buttons can be employed for various functions 
but, as will be clear from the foregoing, the operation can be made 
semi-automatic or completely automatic on a continuous basis if desired. 
Sensor 13d encapsulated in liquid-tight graphite protective tube 13e is 
shown disposed beneath the surface of the mass of molten metal 104 in the 
charge well and may representatively be a Honeywell Dialatrol.TM. or 
Electronic 15.TM. or Barber-Coleman equivalent Model 560.TM. thermocouple, 
for sensing the temperature adjacent to the exit port of delivery conduit 
21. Should the temperature of the molten metal pool 104 in the charge well 
drop below a certain predetermined level, the rate of feed of new or used 
unmelted starting metal chips into the charge well via delivery conduit 21 
may be reduced or feed stopped completely until the temperature again 
reaches a favorable predetermined higher level to accommodate further feed 
and immediate dissolution of the dissipated chips 11d into the main mass 
of molten metal 104. 
Within the chip charger 10 compaction is effected by means of rotation of 
feeder fingers 16 on feeder shaft 37 and extrusion is effected by means of 
feed screw auger 17 whereby the loosely-packed chips 11b are compacted and 
then extruded, simultaneously with injection of inert gas such as nitrogen 
through inert gas injection port 43, into delivery conduit 21 in the form 
of a densified mass comprising compacted and extruded chips 11c which 
substantially fill the delivery conduit 21 and are caused to move 
therealong by the compaction-extrusion force until they burst from the 
open end of the delivery conduit 21 beneath the surface of the molten mass 
as dissipated chips 11d at which point they rapidly dissolve into the mass 
of molten metal 104 with a minimum of oxidation and delay and with an 
extremely high degree of utilization efficiency. 
The compactor-extruder 55 with its component parts as just described 
operates to compact and extrude the loosely-packed chips 11b into 
compacted chips 11c and thence through die holder 18 holding replaceable 
die 19 which has an orifice 19A comprising rifling 19B through which the 
thus-compacted chips 11c are forced under pressure by rotation of the feed 
screw auger 17 in the form of compacted chips 11c which substantially fill 
delivery conduit 21 and which move along delivery conduit 21 in the form 
of a densified mass until the chips burst from the submerged end of 
delivery conduit 21 into the mass of molten metal 104 where they are 
substantially immediately dissolved into and become a part of the molten 
metal mass 104 itself. 
The metal chips and especially aluminum chips have a density of 
approximately 15 to 20 pounds per cubic foot before compacting and a 
greater density, e.g., approximately 68 or so pounds per cubic foot, after 
compacting, with the range being between about 55 and 80 pounds per cubic 
foot at least during the time the compacted chips 11c are proceeding along 
delivery conduit 21 into the molten metal mass 104. The preferred rage of 
density of the compacted chips is 65-70 pounds per cubic foot. 
Alternatively stated, the density of the mass of chips 11c is preferably 
maintained between about 30 and 60 percent of the density of the solid 
metal involved, especially when the metal is aluminum, with the optimum 
range being between about 40 and about 50 percent of the density of the 
solid metal, and the optimum being at approximately 42 percent of the 
density of the solid metal itself. Too little is not recommended as 
operative or safe and much more requires greater compaction-extrusion 
pressure and more elaborate equipment. This limited densification assists 
in an improved melting of the chips and results in a more rapid melt rate, 
maintaining an equally satisfactory reduction in melt loss as in my 
earlier patent, but moreover permits employment of considerably less 
compaction and extrusion pressure and consequently also much less 
expensive equipment. 
Another advantage of the densification of the chips to such a limited 
extent (but not to the extent of a completely solid rope or chain of 
briquettes as disclosed in my earlier patent), is that the densification 
reduces the air space and entrained oxygen which is introduced into the 
molten metal bath and thereby eliminates or substantially reduces the 
oxidation of the chips before and at the time of entering the molten metal 
bath, thereby reducing or substantially eliminating the formation of 
oxides in the molten metal with its attendant loss to oxide, while 
simultaneously attaining a much more rapid dissolution rate. A further 
adjunctive advantage is that in the present method and apparatus there is 
provided the possibility of adding an inert gas such as nitrogen to 
displace the oxygen ordinarily entrained in chips, with still further 
advantageous oxide elimination. 
Therefore, as the metal chips 11c fill the delivery conduit 21, they do not 
compact to the same high degree as a solid briquette or solid rope, being 
only in compacted or densified condition, but they created a plug in the 
conduit 21 which eventually becomes a full-length plug so that molten 
metal from the bath 104 does not enter the conduit, which would effect 
premature melting of chips within the conduit, thereby causing it and the 
chip-charging apparatus to jam, as it is just as possible for the molten 
metal to freeze up in the conduit, which is at a temperature lower than 
the melt temperature, as it is for the melt itself to freeze up because of 
the maintenance of an inadequately high temperature therein. Chip charging 
according to the invention should therefore be and preferably is operated 
on a continuous or at least semi-continuous basis to avoid freezing up 
which might involve an initial premature melting within the delivery 
conduit, especially due to entry of molten metal thereinto. The operation 
therefore commences with the delivery conduit out of the molten metal 
bath, the charge of compacted chips 11c into the conduit is begun along 
with introduction of inert gas such as nitrogen, the plug is created, the 
conduit is filled with the mass of compacted chips 11c, and then the 
chip-charger apparatus 10 of the invention is lowered so that its delivery 
conduit 21 dips into the molten metal bath, whereupon the operation runs 
continuously with continuous feed to keep the delivery conduit 21 full 
until it is desired to discontinue the operation, at which time the 
delivery conduit 21 and/or the entire chip-charging apparatus 10 is 
elevated, pivoted, or otherwise removed from the mass of molten metal 104 
before discontinuing feed of compacted chips 11c within the delivery 
conduit 21. 
As pointed out in the foregoing, at any point at which a sensor or other 
control, including manual control, switches the operation to proceed, the 
sequence should be: first feed until the delivery conduit is full of 
compacted chips and only then pivot or otherwise lower the delivery 
conduit into the mass of molten metal, and thereafter continuously feed 
until it is desired to discontinue or until a sensor determines that 
discontinuance is in order, at which time the sequence is: first elevate 
and thereafter discontinue feed, since the reverse is fraught with the 
possibility that discontinuance of feed prior to elevation, pivoting, or 
other removal of the delivery conduit from the mass of molten metal may 
enable molten metal to enter into the delivery conduit and freeze up 
therein with its attendant serious problems, as will be apparent to one 
skilled in the art. 
IN GENERAL 
The method and apparatus of the present invention is particularly adapted 
for use in connection with nonmagnetic metal scrap such as brass, 
aluminum, aluminum alloys, and the like, and such nonmagnetic metal scrap 
may conveniently be separated from a mass of metal scrap including also 
ferrous, ferric, or other magnetic chips by the employment of magnetic 
separation means, as is now well known and established in the art. 
Although, in referring to the foregoing detailed description of the 
invention and to the drawings, reference is made to the employment of a 
thermocouple or sensor for sensing the temperature in or in close 
juxtaposition to the molten metal in the charge well of the reverberatory 
furnace, which may be connected through a potentiometer or the like to an 
on-off switch or rheostat, for controlling the introduction or speed of 
introduction of compacted chips into the charge well, it should be clear 
that any equivalent electrical and/or mechanical arrangement may be 
employed whereby, when the temperature sensed in the charge well, or 
otherwise at or near the point of introduction of fresh metal (either used 
or new, but in any event to be melted) into a molten metal bath, reaches a 
level which is considered sufficiently low to represent a potential danger 
in the form of excessive crystallization or solidification (due to a 
temperature drop to below that required for rapid melting of new metal in 
the vicinity of the new metal introduction), the rate of introduction of 
new metal into the molten metal bath is diminished or discontinued until 
the temperature can rebound to a safe level, whether this be by reducing 
the rate of operation of the compactor-extruder and/or the feed into the 
same or by completely switching off one or the other or both of such 
means, and/or by retracting, pivoting, or otherwise elevating the delivery 
contuit and/or the entire chip-charging apparatus so as to take the 
delivery conduit out of the molten metal bath, all until an adequate 
temperature is again sensed in or near the point of new metal introduction 
into the molten metal bath so that the previously-existing potential 
problem is no longer of concern. 
Whereas, in this Specification and claims, reference is frequently made to 
"metal chips", this is to be understood as encompassing metal chips of 
various almost unlimited proportions, configurations, and dimensions, but 
particularly to include small pieces and/or particles, likewise of 
extremely variable dimensions, and in general the term "metal chips" is 
employed herein as having the usual meaning to one skilled in the art, 
being inclusive not only of parts, pieces, particles, and fragments of the 
usual type from scrap, but also previously-unused metal in standard or odd 
configurations remaining from previous molding, extruding, casting, 
rolling, or like metal processing operations, and it goes without saying 
that inconveniently large pieces can be reduced in size in any convenient 
manner and employed as metal chips and that, accordingly, any suitable 
metal, whether scrap or otherwise, can be converted into chips and 
employed in the method and apparatus of the invention, whether new metal 
or previously used metal, including even and especially new and used 
aluminum sheet and can scrap, when it is determined that such further 
processing into new metal is required or desired by the operator. 
It is thereby seen from the foregoing that the objects of the present 
invention have been accomplished and that a novel, efficient, improved, 
and economic method for the introduction of metal chips into a molten mass 
of the metal of which said chips are formed, involving compacting and 
extruding said metal chips and then introducing the compacted metal chips 
into the molten metal bath in the form of a densified mass, preferably 
having certain defined density characteristics, which dissociates or 
disperses upon "exploding" from the exit port of a delivery conduit at a 
point beneath the surface of the molten metal bath, all in accord with the 
foregoing, has been provided thereby, as well as apparatus for use in 
carrying out the said method, and whereby all of the previously-mentioned 
advantages have been attained and the shortcomings of the prior art have 
been obviated. 
Although the preferred embodiments of the invention have been illustrated 
in the accompanying drawings and described in the foregoing description, 
it is to be understood that the invention is not limited to the 
embodiments disclosed or to the exact details of operation or exact 
compounds, compositions, methods, or procedures shown and described, since 
the invention is capable of numerous modifications, rearrangements, and 
substitutions of parts and elements and other equivalents, whether 
metallurgical, chemical, electrical, or mechanical, without departing from 
the spirit or scope of the invention, as will readily be apparent to one 
skilled in the art, wherefore the present invention is to be understood as 
limited only by the full scope which can be legally accorded the appended 
claims.