Note: Descriptions are shown in the official language in which they were submitted.
~,,?,~ J~
-1- Pre~ 3/jlt
METHOD AND APPARATUS FOR CLEANING AND DRYIMG METAL CHIPS
-- ._------ . :
IELD OF INVENTION
Preparation of dry metal chips, especially scrap
metal chips, illustratively brass and aluminum, for
further use, as by reintroduction into a molten mass of
metal of which said chips are formed. Drying of said
chips by removal of fluid thereon, whether aqueous or
organic, e.g., hydrocarbon, in nature, or both. Method
and apparatus for so doing. This invention: Drying
and cleaning of chips so that they do not require
cleaning prior to entry into the present apparatus
and process; final drying of chips as effected in a
jacketed rotary drum dryer or jacketed screw conveyor
heated by products of combustion from the combustion
chamber surrounding a heated cyclone separator at a
previous step in the process.
PRIOR ART
With the value of metal chips, especially brass
and aluminum chips, constantly on the increase, and
-~- Prem 3/jlt
with scrap metal chips now valued at between twenty and
fifty cents per pound, the recovery and utilization of
metal chips, but especially scrap metal chips, has
become more and more advantageous from an economic
standpoint. It is today possible to clean metal chips
chemically in the presence of a detergent and then
vaporize excess water or burn off the oil from chips
thermally in a controlled combustion apparatus such as
a rotary drum typeO This provides essentially dry
metal chips when a low order of cost effectiveness can
be tolerated or absorbed, but unfortunately essential
"dryness" is necessary in all cases in view of the fact
that metal chips cannot be employed in a moisture-
containing state and hydrocarbon or other cutting-
oil fluids adhering thereto must also be removed inorder for such metal chips to be capable of reuse.
Although such prior-art apparatus and procedure as
previously mentioned have been the best available
up to the present time, they have proved relatively
uneconomic ~n practice, and other alternative procedure
and equipment previously available for carrying out the
same have also proved uneconomic and unsatisfactory,
especially upon a larger scale such as presently
required to meet the demands of industry for larger and
larger quantities of chips which can be reclaimed and
recycled for further use.
The method and apparatus of the present invention
provide long-awaited improvements in both process and
apparatus for the removal of either or both of moisture
and oily contaminants from metal chips on an economic
basis at the very commencement of their reentry into
the stream of commerce. The present invention also
permits the introduction of starting chips into the
present apparatus and process ~ithout precleaning
if desired, and further provides a final drying step
~2~3;23~
-3- Prem 3/jlt
and apparatus therefor which utiliæes hot products of
combustion from the combustion chamber surrounding a
cyclone separator employed in a previous s~ep of the
process for efecting heating in the final drying step.
OBJECTS OF THE INVENTIO~
It is accordingly an object of the present
invention to provide a new and improved process for the
cleaning of metal chips, especially scrap metal chips,
to remove moisture and/or oily residual contaminants
therefrom. It is another object of the invention to
provide such a process which is economically feasible
and in which maximum utilization of energy available
from the contaminated chips themselves is employed in
the process of cleaning and dryin~ the same. Another
object of the invention is the provision of such a
process which is particularly adaptable to starting
chips which are prewashed and substantially oil free
whereas, in another preferred embodiment of the
invention, the process is particularly adapted to the
employment of starting chips which have not previously
been washed with water plus detergent or the like and
which accordinyly contain both water and oil residues.
Still another object of the invention is the provision
of a superior method for the provision of cleaned and
dried metal chips suitable for employment in industrial
processes whereby scrap metal chips may advantageously
reenter the stream of commerce in an advantageous form
and under more advantageous economic conditions than
previously available. Still an additional object of
the invention is the provision of apparatus which
is admirably suited for employment in the said process.
-4- Prem 3/jlt
Yet an additional object of the invention is the
provision of a unique combination of apparatus with
unique communication cond~itry or circuitry there-
between which is in turn uniquely and advantageously
designed for use in carrying out the process of the
invention. Still additional objects of the present
invention are to provide apparatus and procedure which
does not demand prewashing of the starting chips, but
which may be applied to relatively dirty chips because
cleaning is also effected during the process, as
well as a novel final chip drying step and apparatus
therefor which utilizes products of combustion from a
previous step for heating in and of the same. Other
objects of the invention will become apparent herein-
after~ and still other objects will be apparent to oneskilled in the art to which this invention pertains.
SUMMARY OF THE INVENTTON
.
The present invention comprises the employment of
a source of hot water and/or steam, which may be a
water jacket surrounding the combustion chamber of
cyclone separator means utilized for drying chips in
a late stage of the process, for the washing and
cleaning of starting chips introduced at an early
stage in the process, preferably at or ahead of
a continuous centrifuge or "wringer" which may be
employed in the process~ with associated valving and
conduitry, together with an optional source of solvent
and/or detergent for embodiment thereof in said steam
and/or hot water, for purposes of effecting cleaning of
the starting chips from the dirt and or hydrocarbon or
other oil or grease usually associated therewith,
as an integral part of the overall process. In
addition, the invention comprises the employment of a
jacketed rotary drum dryer or jacketed screw conveyor
5 ~g3~30 Prem 3/jlt
for a final drying of the chips before exit from the
process, with heating of the rotary drum dryer or screw
conveyor being effected by the utilization of hot
products of combustion exited from a combustion chamber
surrounding the cyclone separator means employed in a
previous stage of the process~
The invention, inter alia, otherwise comprises the
following:
In a metal chip drying apparatus, the combination
comprising cyclone separator means having inlet means
for the entry into said cyclone separator means of
gas-entrained metal chips, outlet means for the exit of
dried chips from said cyclone separator means, outlet
means at the opposite end of said cyclone separator
means for the exit of exhaust gases therefrom, combus-
tion chamber means about the outer wall of said cyclone
separator means for the combustion of fuel therein,
inlet means into said combustion chamber means for the
entry of heat and flame thereinto, burner means associ-
ated with said inlet means into said combustion chambermeans and with fuel source means, and outlet means for
exit of gaseous products of combustion from said com-
bustion chamber means; such a combination additionally
comprising water-jacket means about said combustion
chamber means having cold-water inlet means and hot-
water outlet means; such a combination also comprising
continuous centrifuge means including chip inlet means
and discharge outlet means for exit of gas-entrained
chips from said centrifuge means, together with associ-
ated conduit means, which associated conduit meansis connected from said discharge outlet m~ans to
said inlet means into said cyclone separator means;
such a combination also comprising conduit means
-6~ 3Z3~ Prem 3/jlt
associated with said combustion chamber outlet means
and in communication with said chip inlet means of said
continuous centrif~ge means, thereby forming a circuit
between said combustion chamber means through said
outlet means thereof and continuous centrifuge means
via said chip inlet means of said continuous centrifuge
means and thence out of said continuous centrifuge
means via said discharge outlet means thereof and
associated conduit means into said cyclone separator
means via said inlet means thereof; such a combination
also comprising rotary airlock means ahead of said chip
inlet means into said continuous centrifuge means;
such a combination also comprising automatic self-
unloading solids separator means at a point in said
circuit between said rotary airlock means and said chip
inlet means of said continuous centrifuge means; such a
combination also comprising rotary airlock means
downstream from said dry chip outlet means ~f said
cyclone separator means; such a combination wherein the
said combu~tion chambe~ means is a part of afterburner
furnace means and including return conduit means for
conducting exhaust ~ases from said outlet means of said
cyclone separator means into said combustion chamber
means; such a combination also comprising rotary
airlock means ahead of said chip inlet means of said
continuous centrifuge means and also comprising rotary
airlock means down stream from said chip outlet means
of said cyclone separator means, and such a combination
also comprising automatic self-unloading solids
separa~or means in said circuit between said rotar~
airlock means located ahead of said chip inlet means of
said continuous centrifuge means and said chip inlet
means.
Also, a process for ~he prod~ction of dry metal
chips by the removal of fluid therefrom comprising the
_7_ 129323~ Prem 3/~lt
following steps:
entraining fluid-containing metal chips in a gas,
providing a cyclone separator having a wall, said wall
comprising internal and external surfaces, heating a
substantial portion of said wall of said cyclone
separator to fluid-vaporizing temperature, introducing
said gas with entrained fluid-containing chips into
said cyclone separator, causing said fluid-containing
chips to contact the internal surface of said heated
wall of said cyclone separator thereby purging and
vaporizing fluid from said chips, exhausting hot
gases including entrained vaporized fluid purged from
said chips from one end of said cyclone separator, and
exiting dried metal chips from the other end of said
cyclone separator; such a process wherein said fluid-
containing metal chips are moisture-containing metal
chips or oil-containing metal chips; such a process
wherein said metal chips are moisture-containing metal
chips and wherein the internal surface of said wall
of said cyclone separator is heated to a temperature
sufficient to vaporize said moisture, and including the
step of exhausting gases including entrained vaporized
moisture from said chips at one end of said cyclone
separator and preferably wherein the internal surface
of the wall of the cyclone separator is heated to
a temperature between about 250 and about 450CF;
such a process wherein said metal chips are oil-
containing metal chips and wherein the internal surface
o~ said wall of said cyclone separator is heated to
a temperature su~ficient to vaporize said oil, and
including the step of exhausting gases including
entrained vaporized oil from said chips at one end
of said cyclone separator and preferably wherein the
internal surface of the wall of the cyclone separator
is heated to a temperature between about 900 and about
-8- 1293Z30 Prem 3/jlt
1100F; such a process wherein said heating of the wall
cyclone separator is effected by combustion in a
combustion chamber surrounding said cyclone separator,
and such a process wherein said combustion is in a
combustion chamber which is a part of an afterburner
furnace; such a process wherein said afterburner
furnace is fueled at least in part by exhaust gases
including entrained vaporized oil purged from said
chips in said cyclone separator and including the
step of conducting said exhaust gases to said after-
burner furnace; and such a process comprising the step
of providing a water jacket surrounding said combustion
chamber for purposes of heating water in said water-
jacket and conducting said heated water to a chip-
washing step at or near the beginning of the process.
Moreover r such a process wherein extractable 1uid is
removed from the starting metal chips centrifuaally in
a continuous centriEuge before introduction of the gas
containing entrained chips into the cyclone separatorr
and wherein gas entraining said metal chips from said
continuous centrifuge is conducted from said continuous
centrifuge into said cyclone separator; such a process
including the step of utilizing the combustion of
exhaust gases including entrained vaporized oil purged
from said chips for heating of said wall of said
cyclone separator; such a process including the
step of exhausting gaseous products of combustion from
said combustion chamber and conducting the same to and
introducing the same into said continuous centrifuge
for the heating and entrainment of starting metal chips
therein; such a process wherein the temperature of
the gaseous products of combustion conducted to said
continuous centrifuge from said centrifugal separator
is between about 220 and about 300nF for water-
containing chips and between about 450 and about 7S0F
12~323()
-9- Prem 3/jlt
for oil-containing chips. Finally a process for the
production of dry metal chips by the removal of fluid
therefrom comprising the following steps: entraining
fluid-con~aining metal chips in a gas, providing a
cyclone separator having a wall, said wall comprising
internal and external surfaces, heating a substantial
portion of said wall of said cyclone separator to
fluid-vaporizing temperature, introducing said gas with
entrained fluid-containing chips into said cyclone
separator, causing said fluid-containing chips to
contact the internal surface of said heated wall of
said cyclone separator thereby purging and vaporiziny
fluid from said chips, exhausting hot gases including
entrained vaporized fluid purged from said chips
from one end of said cyclone separator, and exiting
dried metal chips from the other end of said cyclone
separator, heati.ng said wall of said cyclone separator
to fluid-vaporizing temperature by effecting combustion
in a combustion chamber surrounding said wall of
said cyclone separator, conducting the hot gaseous
products of combustion from said combustion chamber
to and introducing them into a continuous centrifuge,
extracting extractable fluid from starting metal chips
centrifugally in said continuous centrifuge, entraining
said metal chips in said hot gaseous products of
combustion introduced into said continuous centrifuge
from said combustion chamber, and conducting said
gaseous products with entrained chips from said
continuous centrifuge to and introducing the same into
said cyclone separator, thereby providing an essential-
ly closed system; and such a process wherein said
chips contain oil and wherei~n said combustion chamber
is a part of an afterburner furnace and wherein the hot
. gases include entrained vaporized oil and are exhausted
-from said cyclone separator and recycled back and
~Z~3~3~
-10- Prem 3/jlt
employed as fuel for said combustion chamber of said
afterburner furnace.
_HE DR~WINGS:
Reference is now made to the drawings, wherein:
FIG. 1 is a side elevational view of apparatus
according to the invention which may be employed
in carrying out the method of the invention shown
partially schematically and partially in section for
purposes of convenience and simplicity.
FIG. 2 is a side elevational view of another
embodiment of apparatus according to the invention
which may be employed in carrying out another embodi-
ment of the method of the invention, once again being
shown partially schematically and partially in section
for purposes of convenience and simplicity~
FIG. 3 is a side elevational view of another
embodiment of apparatus according to the invention
which may be employed in carrying out a further
embodiment of the method of the invention, being a
combination of certain aspects of FIGS. 1 and 2 as
modified to provide final chip drying and apparatus
therefor, again being shown partially schematically and
partially in section for purposes of convenience and .
simplicity.
DETAILED DESCRIPTION OF T~E INVENTION
The present invention, in both its method and
apparatus aspects, will be more readily understood from
the following detailed description, particularly when
taken in conjunction with the drawings, in which all of
the significant parts are numbered and wherein the same
numbers, or numbers differing by 100, are usually used
-
~Z~3Z3~
~ Prem 3/jlt
to identify the same parts throughout.
According to the present invention, the chips
introduced into the process and apparatus of the
invention do not necessarily require prewashing
or precleaning. The apparatus and process of the
invention are accordingly designed to effect this step
in addition to drying of the chips treated, the step
of cleaning and washing of the chips being conveniently
provided by the provision o a hot wa~er and/or steam
source, which may be built into the equipment itself or
provided from outside, conveniently along with a
source of detergent and/or solvent, for cleansing of
the starting chips of whatever dirt or impurities as
well as hydrocarbon or other oils or grease which may
be carried on the surface thereof as they enter the
process and apparatus of the invention. In addition,
in another embodiment, as representatively shown
in FIG. 3, a further final drying of the chips is
provided, along with means for such drying, the same
being effected by utilization of hot products of
combustion from a previous step in the process.
In FIG. 1 is illustrated apparatus and process
uniquely designed for the production of dried met~l
chips which may or may not have been prewashed. At
the left of the drawing, unwashed chips 11 (not shown)
may be but are in this case not necessarily subjected
to washing in a usual washing unit for the washing of
metal chips with hot water and detergent or the like
which contain in addition the normal oil, dirt, and
other debris ordinarily associated with such chips,
especially of the scrap metal variety. Due to the
unique nature of the apparatus and procedure of the
present invention this prewashing or precleaning step
may be, and usually is, foregone, and the cleaning
carried out as part of the present process. The washed
-12- lZ93230 Prem 3/jlt
or unwashed and preshredded chips 11a are introduced
into chip en~ry means 12 of continuous centrifuge or
wringer unit 10 such as Reclamet models having partic-
ular adaptability to the removal of moisture and/or oil
from the surface of metal chips including their models
TD3000, TD4000, and TD5000, shown generally at 10.
Chip entry means 12 leads into inclined duct 14
emptying into the usual spinner bowl 16 for centrifugal
separation of fluids from chips to the extent possible
in such a device. Centrally of inclined duct 14 is
located rotary bar end separator 21 which doubles as an
airlock under usual operating conditions. Communicat-
ing with inclined duct 14 is air intake and solids
separation exit 22~ in close juxtaposition to rotary
bar end separator and airlock 21 to permit air to enter
the wringer unit because of the suction or vacuum
createcl therein while, at the same time, permitting bar
ends or parts larger than a prescribed maximum to leave
the inclined duct 14 as directed by rotary bar end
separator 21 to exit 22. Weighted damper 23 ~onitors
exit 22, the damper opening when the separated solids
collected at exit 22 reach a predetermined minimum for
temporary opening of the damper~
The usual spinning or centrifugal bowl 16, for
centrifugal separation of liquids from solids in the
heated continuous centrifuge uni~ 10, is rotated by
associated drive. means 18 mounted on base 20 which in
turn is situated upon floor F. Liquid 24, consisting
essentially of water, aqueous detergent solution, oil,
or the like, which is wrung out of the chips by the
continuous centrifuge unit, exits therefrom via chip
wringer exit 26 whereas the wrung chips 11b, still
carrying entrained moisture and whatever other liquid
not wrung therefrom in continuous centrifuge unit 10,
in an amount of usually approximately two ~2~ percent
-13- 1 ~3~3~ Prem 3/jlt
by weight, exit said unit via exit pipe 28 and enter,
along with entraining gases, essentially steam, an
entry conduit 30 communicating with separatory unit
entry means 32.
The cooperating heated separatory unit, shown
generally at 50, comprises cyclone separator proper 52
having an external wall 54 and surrounding combustion
chamber 66, of mild or stainless steel or the liket
which is in turn surrounded by an external water
jacket 70, possibly glass or otherwise lined, as is
conventional in the art of water-jac~eting. The
external water jacket 70 has a cold water inlet 72
and a hot water/steam outlet 74, from which hot water
and/or steam may conveniently be conducted back into
the process as Eurther disclosed hereinafter~ Com-
bustion means 60 comprises combustion chamber 66
surrounding cyclone separator external wall 54 and
combustion burner 62, fueled with oil or gas from a
source not shown, and communicating via hollow burner
mounting means 64 with internal combustion chamber 66
for directing heat and flame thereinto.
Upon entry of wrung chips 11 b entrained in gases
tmainly steam) via separation unit entry means 32,
solids comprising wrung chips 11 b follow spiral path 80
internally in contact with and along the hot wall 54 of
separator 52 wherein and whereby they are dried by
their contact with the internal surface of separator
external wall 54, which is heated by internal combus-
tion chamber 66 surrounding said separator wall 54 to a
temperature of about 350F, and finally pass out of
said separator 52 via separator solids exit means 56
and through optional but preferred rotary airlock 57 as
clean and dry chips 11c for collection and reuse.
Final exhaust gases, at or about 325F, pass out
of the separator unit at the top thereof via separator
~ 93;~
-14- Prem 3/jlt
gas exit means 58 and may be allowed to escape to
the atmosphere or be captured and disposed OL in an
afterburner or baghouse or the like if desired.
Simultaneously, products of combustion from
combustion chamber 66 in the combustion means 60
surrounding separator wall 54 pass out of said combus-
tion chamber via exit means 67 at a temperature of
approximately 250F and are conducted through combus-
tion chamber exit conduit 68. The hot combustion
gases th~n enter inclined duct 14 of the continuous
centrifuge unit 10 through gaseous combustion product
entry and return means 69 from which point they are
drawn with chips via chip inlet 15 into the continuous
centrifuge unit 10 by means of the considerable vacuum
or suction provided therein. Hot gas entry and return
means 69 feeds into air intake and solids separation
exit 22 which in turn leads directly into duct 14 of
continuous ce~trifuge unit 10~ Upon entering into
duct 14 and spinner bowl 16, the gaseous products of
combustion resulting from the combustion effected in
combustion means 60 assist in the vaporization of fluid
materials carried by the starting metal chips 11a
and finally exit centrifuge unit 10 at exit 28 along
with wrung chips 11b.
In the adaptation of the present invention,
conduit CA is provided between hot water and/or steam
exit port 74, whereby hot water and/or steam exits from
water jacket 70. This conduit CA leads to valve V1,
whereby distribution to other sections of the system is
effected by means of conduitry involving conduits C1,
C2, C3, and C4. In addition, a source of detergent
D and a source of solvent S are provided and so located
with appropriate connecting conduitry so as to enter
conduit CA, when desired, through valves V2 and V3.
Thus, when it is known that the starting chips contain
-15- ~93~3~ Prem 3/jlt
grease, or hydrocarbon or other oil, the solvent supply
source S can be activated through its connecting
conduitry and valve V2 whereas, when extremely dirty,
but not necessarily grease-, hydrocarbon- or other
oil-containing chips are involved, detergent source D
can be activated, in turn providing detergent into the
system through its connecting conduitry and valve
V3 in~o main conduit C~ ahead of main distribution
valve Vl. Alternatively, both sources may be activated
for supply of both solvent and detergent into the
system when desired. Valve V1 may comprise a single or
a plurality of options connecting it between conduit CA
and one or more of conduits C1, C2, C3, and C4.
When selected, conduit C1 returns the hot water
lS and/or steam together with any entrained solvent and/or
detergent directly to separatory unit entry means 32
via entry conduit 30 through an approprîate opening
therein~ This is a preferred return conduit and a
preferred manner of operation, inasmuch as it brings
the injected hot water and/or steam and/or solvent
and/or detergent into contact with the chips entering
the cyclone separator 52 with a minimum of circuitry,
conduitry and valving, important considerations when it
is desired to minimize equipment size and costs.
When conduit C2 is selected, the conduitry feeds
hot water and/or steam, with or without accompanying
detergent and/or solvent, through conduit C2 directly
into the spinner bowl 16 of continuous centrifuge 10
throu~h a suitable opening provided in the cover
thereof.
When conduit C3 is selected, the hot water and/or
steam enters conduit 68, which is the conduit provided
for products of combustion exitiny the combustion
chamber 66 surrounding centrifugal separator 52 via
exit port 67, and is thereupon transported, along
3Z3~
-16- Prem 3/jlt
with any entrained and/or dissolved solvent and/or
detergent, through hot gas entry and return means
6~ into air intake and solids separation exit 22
which in turn leads directly into duct 14 of continuous
S centrifuge unit 10.
In case conduit C4 is selected, the steam and/or
hot water and any entrained or dissolved detergent
and/or solvent proceeds directly into duct 14 of
continuous centrifuge unit 10. Arly or all of these
options may he selected or preselected by the operator
and effected either manually or automatically.
Alternatively or additionally, further conduitry
CB is provided at a suitable point in chip wringer
housing 26a above chip wringer exit 26, in turn being
activated by means of valve V4 which permits the steam
rising from the exit housing 26a to be sucked into
a further extension of the conduitry CB and further
conduitry identiied as C5 and C6, either into solids
separation exit 22 or gaseous combustion product entry
and re~urn means 69, as selected by activation of valve
V6, this additional conduitry ensuring that all of the
possible hot water and/or steam generated in the system
is utilized for the chip cleaning operation, as will be
apparent to one skilled in the art from the foregoing
explanation.
In a second embodiment of the invention, as
illustrated in FIG. ~, the metal chips subjected to the
process and apparatus of the invention are previously
unwashed chips, which definitely contain not only
residual dirt and moisture but also oil and/or grease.
For this reason provision is not made for the internal
procurement and utilization of hot water~ as in the
embodiment of FIG. 1, but economic and other factors
may dictate the selection of the previously-described
embodiment, or vice-versa, since more drastic energy
~323~1
-17- Prem 3/jlt
measures and greater capital outlay are required for
the drying of chips which have not previously been
subjected to any washing process, hence the afterburner
unit in this embodiment.
In FIG. 2 r the heated separator unit is shown
generally at 150, the heated continuous centriuge or
wringer unit at 110, and the entire combination of
apparatus at 101 (cf. 1 in FIG. 1).
As shown in FIG. 2, unwashed chips 111, replete
with the usual moisture, oil, grease, dirt, and otner
assvciated debris, pass along inclined duct 114 leading
into the usual centrifugal or spinner bowl 116 after
having entered at chip entry means 112 following
subjection to a shredder 125, illustratively a high-
torque low-speed hydraulically-driven turnings shredder
such as Premelt Shredder Model 2436 from Premelt
Systems, Inc., Kalamazoo, Michigan, USA. As shredded
chips 111a proceed in inclined duct 114 they contact
rotary bar end separator 121 which doubles as an
airlock under usual operating conditions. Airlock 121
again cooperates with solids separating exit 122 to
direct bar ends and metal chips above a predetermined
maximum size to exit from the inclined trvugh 114 prior
to entering into the centrifuge proper at chip inlet
115, exit 122 being monitored by weighted damper 123
which opens when the separated solids collected at exit
122 reach a predetermined minimum for temporary opening
of the damper. Spinner bowl 116 is again rotated by
associated drive means 118, once again mounted on base
120 in turn situated upon floor F. The concentration
of residual liquid on chips 111b upon leaving centri-
fuge or wringer 10 is approximately two (2) percent by
weight, most of which is oil of a hydrocarbon or other
combustible nature.
Once again the continuous centrifuge unit shown
~93Z3~
-18- Prem ~/jlt
generally at 110 is, as shown, associated with separa-
tion unit shown generally at 150. Separation unit 150
comprises cyclone separator proper 152 including
cyclone separator exterior wall 154 and separated
solids exit means 15Ç through which separated solids
exit via optional but preferable rotary airlock
157. At the top of cyclone separator 152 is separated
gas exit 158 through which hot gases exit from the
separator 152. Metal chips 111b entering the cyclone
separator 152 follow spiral path 180 in contact with
the interior ~urface of heated cyclone separator
exterior wall 154 en route to separated solids exit
means 156.
Surrounding separator 152 is afterburner furnace
160 comprising an external housing 161 of mild or
stainless steel or the like, as is conventional in the
furnace art, which houses an internal combustion
chamber 166 surrounding the cyclone separator exterior
wall 154. The external housing 161 of the afterburner
furnace 160 is provided with a refractory lining 163,
as is also conventional in the furnace art. Combustion
burner 162, fueled with oil or gas from a source not
shown, provides heat and flame directed into internal
combustion chamber 166 via hollow burner mounting 164
whereby burner 16~ i~ mounted upon external housing 161
of afterburner furnace 160 and through which mounting
burner 162 communicates with the internal combustion
chamber 166. Hot exit gases leaving cycIone separator
152 via gas exit means 158, in this embodiment com-
prising vaporized hydrocarbon and other combustible
oils, are cycled by separated gas return conduit 159
communicating with internal combustion chamb~r 166 back
into combustion chamber 166 where they provide suitable
fuel for the after-burner furnace 160.
The metal chips 111b en~ering the cyclone sepa-
Z3~
-19- Prem 3/jlt
rator 152 via entry means 132 from entry conduit
130 are heated to an extremely high temperature of
approximately 1000F duriny ~heir passage through
cyclone separator 152 while describing spiral path 180
along and in contact with the interior surface of
extremely hot exterior wall 154 of separator 152,
finally passing cut of separator solids exit means 156
and through optional but preferable rotary airlock 157
from which the cleaned and dried chips 111c exit and
may be recovered for further use.
The entire separator unit 150, as shown, including
cyclone separator proper 152 and afterburner furnace
160 and associated conduits, along with combustion
burner 162, are all supported on support means 151, in
turn mounted upon floor F.
The hot gases, which are products of combustion
of the combustion which takes place in the combustion
chamber 166 of afterburner furnace 1~0, are led from
internal combustion chamber 166 via combustion chamber
exit means 167 into combustion chamber exit conduit 168
where the products of combustion in gaseous form at a
temperature of approximately 650 F, controlled if
necessary by employment of dilution air, finally
enter inclined duct 114 via hot gas return inlet 169,
which communicates with separated solids exit 122,
whereupon they are conveyed into the continuous cen-
trifuge or wringer unit 110 together with chips 111a
entering from shredder 125 past rotary bar end separa-
tor 121 and along inclined duct 114 to assist in
the cleaning and drying of the new batch of chips 111 a
in the continuous centri~uge or wringer 110 and the
spinner bowl 116 thereof into which the hot return
gases and chips are suctioned via chip inlet 115 by
means of the vacuum created therein.
A controlled portion of the products of combu~tion
` ```~ ~2~323~
-20- Prem 3/jlt
exiting from the combustion chamber 166 after leaving
combustion chamber exit means 167 is vented to the
atmosphere through exhaust means in the form of exhaust
stack 170 via flue 172 communicating with combustion
chamber exit means 167, the final exhaust temperature
of those products exiting through exhaust stack 170
being on the order of 1250F. It will be understood by
one skilled in the art that the height of the exhaust
stacX must be sufficient, e.g., 20 or 30 feet, to cause
an upward flow of gases sufficient to create a negative
pressure or natural draft on the products of combustion
exiting the combustion chamber through exit 167 or,
alternatively, that such negative pressure or natural
draft can be established by use of an exhaust fan (not
shown).
According to this modification of the present
invention, a hot water and/or steam source is provided,
as shown, in this case rom outside the existing
system, since no water jacket surrounding the com-
bustion chamber l66 is provided.
This external source, together with suitableconduitry CAA, detergent source D and solvent source S,
along with appropriate valving V11 and V12, provides
the source of hot water and/or steam and/or detergent
and/or solvent for introduction into the system. Main
conduit CAA is effectively connected by valves V11 and
V12 for introducing the hot water and/or steam and,
when desired, entrained and/or dissolved solvent and/or
detergent, directly through valve V13 and conduit C11
into entry conduit 130 and thence together with chips
into heated cyclone separator 152 through entry port
132. Alternatively or concurrently, valve V13 is
closed (or also kept open) with respect to conduit C11
and opened to provide a flow of hot water and/or steam
and/or entrained and/or dissolved solvent and/or deter-
` ~L29;~;23~
-21- Pr~m 3/jlt
gent as far as valve V14, where it may be diverted
through conduitry C14 into inclined duct 114 through an
appropriate opening therein, or allowed to proceed
to valve V15, from ~hence it may be permitted to
proceed through conduitry C12 and/or C13 either or
both into combustion product return conduit 168 and/or
into spinner bowl 116 through an appropriate opening
therein. Alternatively, all of these valves may be
programmed to open for entry of the hot water and/or
steam into the system through all of the p~rts or
only a selected number of them, either manually or
automatically, as will again be apparent to one skilled
in the art. Once again, conduitry CBB is provided to
communicate with an appropriate opening in chip wringer
exit housing 126a which, together with appropriate
valving V16 and V17 and associated conduitry Cl5 and/or
C16, once again conducts steam from this secondary
source into one or both of solids separating exit 122
and hot gas return outlet 169, and thence into inclined
duct 114 and directly into continuous centrifuge or
wringer unit 110 and the spinner bowl 116 thereof,
thereby once again utilizing the introduced hot water
and/or steam and energy to the maximum possible extent.
As to either of the foregoing adaptations or
modifications according to the invention, it will
be app~rent that the starting chips need not be clean
or prewashed or precleaned, inasmuch as th~ hot
water and/or steam provided according to the present
invention effects cleaning as an integral part of
the process and system before drying and expulsion of
the chips th~refrom, so that greasy chips or chips
laden with hydrocarbon oil or the like can readily
be cleaned by the introduction o solvent into the
system along with the hot water and/or steam, and that
normal dirt, moisture, and other impurities not of
~;293Z3~
-22- Prem 3/jlt
an oily or greasy nature can read ily be removed by
the introduction of detergent into the system along
with the hot water and/or steam, or that both may be
employed where desired or required, so that in effect
the invention has now provided r within limits of
feasibility, a completely sel~-contained chip clean-
ing and drying apparatus, system, and process which
eliminates the necessity of prewashing or precleaning
of the starting chips except in the most unusual or
extraordinary cases.
In the embodiment shown in FIG. 3, the source
of hot water and/or steam~ detergent, and solvent,
together with the necessary circuitry involved for
introducing the same into the system, is not shown, but
is of the same nature and type as shown in FIG~ 2 when
and if embodied in the system and employed in the
process. FIG. 3 shows in abbreviated form at 201 a
combination or system substantially like that of FIG.
2, involving continuous centrifuge 210, with its
inclined duct 214 and rotary bar end separator 221,
through which shredded chips 211a proceed in the usual
manner. Airlock 221 cooperating with solids separating
exit 222 for directing bar ends and metal chips above a
predetermined maximum siæe to exit from the inclined
trough 214 prior to entering centrifuge proper at chip
inlet 215, together with monitoring weighted damper
223, are also visible. Spinner bowl 216 rotated by
associated drive means 218 is again mounted on base 220
in turn situated on floor F. The continuous centrifuge
unit 210 is again associated with a separation unit
shown generally at 250, comprising cyclone separator
proper at 252 including cyclone separator exterior
wall 254 and separated solids exit means 256 through
which separated solids 211c exit. Exhaust gases exit
separator 252 through gas exit 258. Metal chips 211b
3~
-23- Prem 3/jlt
entering separator 252 follow the spiral path 280 in
contact with in~erior surface of separator exterior
wall 254 enroute to separated solids exit means
256. Surrounding separator 252 is furnace 2Ç0 compris-
ing external housing 261 housing internal combustion
chamber 266 surrounding separator exterior wall 254 and
again provided with refractory lining 263. Combustion
burner 262 is fueled with oil or gas from a source
not shown and provides heat and flame directed into
internal combustion chamber 266 via hollow burner
mounting 264 whereby burner 262, mounted upon external
housing 261 of furnace 260, communicates with in~ernal
combustion chamber 266. Hot exit gases leave cyclone
separator 252 via gas exit means 258. If desired, they
may again be cycled by a separated gas return conduit
communicating with internal combusion chamber back into
the combustion chamber itsel~, where they provide
urther fuel for the afterburner furnace, all as shown
in FIG 2~
Metal chips 211b entering separator 252 via entry
m~ans 232 from entry conduit 230 are heated during
passage through separator 252 while describing spiral
path 280 and finally pass out of separator sollds exit
means 256, the entire separator unit 250 being again
supported on support means 251 in turn mounted upon
floor F.
Hot gases which are products of co~bustion in the
combustion chamber 266 are led from internal combustion
chamber 266 via combustion chamber exit means 267 via
conduit 268 back to inclined duct 214 via hot gas
return inlet 269 from whence they are conveyed into the
continuous centrifuge or wringer unit 210 together with
chips 211a.
However, in this embodiment, combus~ion chamber
exit conduit 268 is interrupted by a jacketed screw
-24- lZ~3Z30 Prem 3/jlt
conveyor or jacketed rotary drum dryer 269, in either
case jacketed with a housing 271 of sheet metal or the
like and provided with inlet port 272 and exit port
273 for the introduction of products of combustion
respectively thereinto and exit therefrom enroute via a
continuation 272 of combustion chamber exit conduit
268 back to continuous centrifuge or wringer unit 210.
The jacketed screw conveyor or jacketed rotary drum
dryer 2~9 is generally of approximately twenty (20)
feet in length, so that the dwell time of chips therein
is approximately five (5) minutes. Dwell time of the
chips therein may be controlled by controlling the rate
of rotation of the rotary drum dryer or the screw
conveyor 269, which is rotated about its longitudinal
axis as is conventional in the art by conventional
means (not shown), all as is well known in the art.
Thus, after exit of dried or partially dried chips 211c
from separator solids exit means 256, they are either
introduced directly or conveyed by suitable conveying
means such as a duct or conduit (not shown) into the
lower end of jacketed screw conveyor or jacketed rotary
drum dryer 269, also mounted by mounting means 270 upon
support means 251, wherein they undergo a more or less
spiral path of travel ending at chip exit 275.
Thus, the already partially-dried chips or dried chips
211c are subjected to a further and final drying
step or procedure involving the employment of hot
products of combustion from combustion chamber exit
means 267 via combustion chamber conduit 268 and the
thus-heated jacket 271 of screw conveyor or rotary
drum dryer 269, and are finall~ discharged therefrom
at chip exit 275, the final drying of the chips
involving only an intermediate use of the existing hot
products of combustion from combustion chamber 266
with an absolute minimum of additional equipment and
~3Z3(J
-25- Prem 3/jlt
operational expense~ Upon exiting from jacket outlet
port 273 via conduct 276 continuation of combustion
chamber exit conduit 268, the still relatively hot
products of combustion are returned to the continuous
centrifuge or wringer unit 210 via the conduitry and
ductwork previously explained.
As will be apparent to one skilled in the art
althoughr in the first embodiment of the process of the
invention as illustrated in FIG. 1, where the main
object may be to remove water or moisture from the
chips (as when starting chips are relatively clean or
where substantially all of the oil has been removed
previously, as by a washing step), the temperature in
the cyclone separator is given as about 350F, the
final exhaust gases may have a temperature of about
325F, and the gaseous products of combustion recycled
back to the continuous centrifuge unit are indicated as
having a temperature of about 250Fr considerably
broader temperature ranges may be involved. Illustra-
tively, in the embodiment of FIG. 1, the temperature
inside of the cyclone separator will generally range
between about 250 and 450F, and the products of
combustion returned to the continuous centrifuge or
wringer will generally be at a temperature between
about 220F and 300F, whereas the temperature of
the exhaust gases leaving the separator will yenerally
be in the range of about 225 to 425F.
In contrast, in the embodiment of FIG. 2~ where
(and whenever) the object is generally to remove
both water and hydrocarbons and other oils, greases,
and other impurities from the chips, and without
previous cleaning, the temperature will generally
be considerably higher. For example, within the
cyclone separator the temperature will be rather
carefully controlled, especially when aluminum chips
~LZ93Z3~
~26- Prem 3/jlt
are involved, but will generally be between about gO0F
and 1100F, usually between about 950F and 1050F.
The temperature of the produc~s of combustion recycled
to the continuous centrifuge or wringer will generally
be at a temperature within the range of about 450F to
about 750~F, as may be readily controlled by the
employment of dilution air to the extent required,
whereas the temperature in the exhaust stack may range
between abaut 1150 and 1450F~
With the apparatus as illustrated in FIG. 3,
the chips 211c exiting separator 252 at exit means
256 are usually at a temperature of approximately 225
F, whereas the products of combustion conveyed by
combustion chamber exit conduit 268 from combustion
chamber exit port 267 are generally at a temperature of
approximately 650 F, at which temperature they enter
entry port 272 of jacketed screw conveyor or rotary
drum dryer 269. Upon emerging from jacket 271 at
exit port 273, the temperature of these products
of combustion is generally approximately 300F and,
upon return to inclined duct 214 and continuous
centrifuge or wringer 210, approximately 250~ F. Thus,
in the embodiment of FIG. 3, products of combustion
inherent in the system and process of the invention
are employed in a final drying of the chips as an
intermediate stage in the uti1ization thereof. The
integrity of the overall system and process is not
diminished except to the extent that the temperature
of the products of combustion upon return to the
continuous centrifuge stage of the process is somewhat
reduced in contrast to the temperature level retained
when the final drying stage, and the apparatus whereby
the same is effected, are omitted.
Whenever cooling of the combustion gases con-
ducted from the combustion chamber ~o the continuous
23~
-27- Prem 3/jlt
centrifuge or wringer is required, a minimum quantity
of oxygen-containing dilution air should be used or
other cooling means, e.g., a heat exchanger in the
conduit 68, 168, or 268, are recommended. Although in
no case should the temperature employed be any higher
than required for efficient and economic operation, as
will be readily understood by one skilled in the art,
the temperature ran~es employed in the embodiment of
FIG. 2 are generally considerably higher than the
temperature ranges employed in the embodiment of FIG. 1
wnen, according to the process of FIG. 1, only a minor
degree of chip cleaning is involved or, e.g., when only
residual water is to be purged or expelled from the
chips, as when most of the hydrocarbon and other oil
has been removed in a washing step preceding entry of
the chips into the process whereas, when there is no
prewashing or precleaning, or only a minimum thereof,
as is usual in the embodiment of FIG. 2, both water
and hydrocarbon as well as other oils and impurities
and contaminants are being removed directly in the
process and the hydrocarbon oils and the like are
available for use as fuel and can be employed by
recycling the effluent gases back into the afterburner
furnace as shown in FIG. 2.
The amount of residual water, plus possibly
some small amount of detergent, solvent, or whatever
in solutionr on the chips as they emerge from the
co~tinuous centrifuge or wringer unit in the embodiment
of FIG. 1, especially when a prewash is employed, is
generally about two percent (2%) by weight whereas,
according to the embodiment of FIGo 2, and whenever no
prewash is employed, the amount of water and hydro-
carbon and other oils remaining on the chip5 upon their
exit from the continuous centrifuge unit will be in
approximately the same range but with a very con-
:~Z~3Z~I~
-28- Prem 3/jlt
siderably higher proportion of oil to total residual
liquid in contrast to the insignificant amount of
oil which remains on the chips upon exit from the
continuous centrifuge or wringer unit when operat-
ing with prewash, which is not necessary accordingto the invention but which, when employed, is most
conveniently associated with the process and the
apparatus of the embodiment of FIG. 1.
Thus, according to the invention, a novel process
for the production of dry metal chips by the removal of
fluid therefrom is provided whereby dry chips can be
obtained either from cleaned or uncleaned starting
metal chips, but wherein precleaning or prewashing
is not a necessary prerequisite, the apparatus and
method employed in the separation unit being by itself
novel and valuable and the apparatus and process as
employed in the separation unit, in combination with
the apparatus and process as employed in the continuous
centrifuge unit, with communicating interconnections,
being all the more industrially advantageous and
valuable, since none of the possibly available fuel
carried by or on said startiny chips is wasted, being
rather employed by means of communication and ~ecircu-
lation means as described in the foregoing to minimize
the amount of new energy which must be provided in the
process for the effective drying of the starting metal
chips of whatever nature and with whatever contaminants
might be present.
An important aspect of the present invention is
that the starting chips may be introduced into the
process in previously uncleaned or unwashed state,
or with any reasonable degree of contamination, without
the necessity of prewashing or precleaning, and be
adequately cleaned and dried within the present system
and process, due to the provision of hot water and/or
~Z~3~3(~
-29- Pre~ 3/jlt
steam, either from an independent source or from a
source within the apparatus employed in the process
according to the invention, if desired together with
solvent and/or detergent, depending upon the original
contaminations as determined to exist upon the chips as
introduced into the process. The additional feature of
the present process, involving final drying of the
chips in drying equipment, utilizing as heati~g agent
the products of combustion from the combustion chamber
surrounding the cy~lone separator used in the preced-
ing step for drying of the chips, is an additional
advantageous aspect of the invention, especially when
the hot products of combustion are recycled through the
final drying apparatus and back into the process at
or just ahead of the continuous centrifuge stage where
initial wringing of the chips is effected.
As far as the apparatus of the invention, the
apparatus involved in the separation unit of the
invention constitutes an entirely new and novel
~0 approach to the drying of metal chips and, while
independently valuable, is o~ course of even greater
industrial value and advantage in combination with the
continuous centrifuge unit, with which it is connected
according to the invention by various communicating
cycling and recycling conduit circuitry for purposes of
obtaining the maximum possible energy and heat for
drying of the chips and for purging liquid from the
chips themselves while minimizing the input of new
energy into the process.
The additional apparatus employed for introduction
of the steam and/or hot water, either from an inde-
pendent source or from the water jacket surrounding the
combustion chamber used for heating of the cyclone
separator, with or without additional sources of
detergent and/or solvent, requires only minimal equip~
:~2~3;~
-30- Prem 3/jlt
ment or apparatus adaptations, as does the conduitry
necessary for heating of the jacketed rotary drum dryer
or screw conveyor for final drying of the chips with
hot products of combustion which are then desirably
recycled back into the circuit at the continuous
centrifuge stage.
Accordingly, both the apparatus and the process of
the present invention constitute an important and
advantageous step forward in the art of providing dry
metal chips, especially scrap metal chips, for reuse
and reintroduction into the stream of commerce.
Whereas, in this specification and ~laims,
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 particlesr likewise of extremely variable
dimensions, and in general the term "metal chlps" 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 process and apparatus o~ 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,
provided, however, that in all cases such metal
~3Z~3
-31- Prem 3/j~t
scraps are of suitably small dimensions so that they
can be employed eficiently in the separator unit
and/or continuous centrifuge or wringer unit according
to the invention without causing damage to or plugging
of the apparatus employed, this ordinarily being taken
caxe of according ~o the skill o the art by preshred-
ding the chips to suitable manageable and utilizable
dimensions.
* * *
It is thereby seen from the foregoing that the
objects of the present invention have been accomplished
and that a novel, efficient, and economic process
for the drying and cleaning of metal chips has been
provided, as well as novel apparatus for use in carry-
in9 out the said process, and whereby all of the
previously-mentioned advantages have been attained and
the shortcomings of the prior art have been obviated.
According to the present invention, the ability
to start with previously unwashed or unclean chips
and to effect both efficient cleaning or washing and
drying thereof in a single unitary process is of course
of great advantage, especially when relatively low
temperatures can be employed, and the concept of
finally drying the chips by means of equipment utiliz-
ing as heating means the products of combustion result-
ing from the heating of the cyclone separator in the
previous step, with final recycling of the products of
combustion back into the process at or about the
continuous centrifuge stage, goes far toward providing
a finished and completely dried chip in a unitary
process of maximum simplicity and involving only
minimal economic outlay.
Although the preferred embodiments of the inven-
` ` ~Z~3Z3~
-32- Prem 3/jlt
tion have been illustrated in the accompanying drawings
and described in the fore~o:ing description, it is to be
unders~ood 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
equivalçnts, whether metallurgical, chemical, 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.
