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Патент USA US2412057

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Patented Dec. 3, 1946
2,412,051
UNITED STATES PATENT OFFICE
FURNACE CONSTRUCTION ‘
Charles W. Nichols, West Orange, N. L, assignor
to Charles W. Nichols, In, New York, N. Y.
Application Marchli, 1944, Serial No. 525,153
4 Claims. (Cl. 263-21)
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1
This invention relates to furnace constructions
of a type particularly adapted, among other pos
sible uses, for the drying and reclaiming of
foundry core sand, and masses of other free-?ow
ing ?nely divided materials, such as clays,
crushed ores and concentrates. The invention
also involves novel methods for such purposes.
The objects of. the invention include the pro
vision of a relatively inexpensive furnace’ con
struction with fire brick lining if desired. With~
in this wall a plurality of superposed chambers
0r zones may be provided as at ll, l2, l3 and I4.
A suitable feeding device as at l5 may be mount
.ed to protrude down through the mid portion of
the roof l6 of the furnace. This feeding device
may include a hopper ll with a cylindrical out
let l8 extending down into the middle of the up
per part of zone II. A vertically extending-ro
tatable shaft l9 may be mounted in suitable bear‘
ings as shown within the feed outlet Hi, this shaft
‘carrying at its lower end a rotatable disc-like
feeding device 20 having on its upper surfaces
struction which may be economically operated
with a high degree of dependability, and which
will thoroughly and uniformly dry or roast ma
~ terials such as above referred to. In its preferred
form the furnace includes a plurality of super
plurality ‘of generally radially extending ribs 'or
posed zones with means within the top of the 15 vanes as at 2| for causing the material as fed, to
upper zone for feeding and projecting the mate
be projected outwardly as at 22 in a direction to
rial in directions to impinge upon the ‘side walls
impinge upon the inside walls as at 23 of the
around within this zone, whereby the material
chamber l I. The shaft l9 may be driven as from
may then fall on to an annular ledge and thence
a motor 24 connected through suitable transmis
through a central opening into the next zone, 20 sion means as at 25.
onto a pile of the material supported on a sta
The lower portion of zone or chamber ll may
tionary hearth. During its fall, the material;
be demarked by a generally annular stepped
comes in contact with a countercurrent ?ow of
ledge formation 26 formed of the brick work, pro
hot gases. The material may then roll down
truding inwardly from the furnace walls and sur
along the sides of such pile through peripheral 25 rounding a central opening 21 which connects
discharge ports in the stationary hearth, and
zone II with the next lower zone l2. It will be
thence into van additional lower zone or zones
noted that the material as it falls in zone H is
where it may be rabbled in the form of relatively
distributed in‘ a generally globular and substan
thin layers, over one or more hearths while be
tially hollow formation, the lower annular por
ing further roasted and finally cooled. If desired,
tion of which comprises the upper side of the
instead of using but two upper zones through
ledge formation 26. In a manner hereinafter ex
which the material falls, three, four or more of
plained, provision is made for a, countercurrent
such zones may be provided, alternate zones hav
stream of hot gas to flow up through opening 21,
ing central and peripheral discharge ports or
thence up through said globular formation and
out through the roof by way of gas discharge con
Various further objects, features and advan
duits as at 28.
tages of the invention will appear from the de»
The upper side of the stepped ledge formation
scription given below taken in connection with
26 may be made such that masses of the material
the accompanying drawing which illustrates by
will accumulate thereon until the natural angle
way of example preferred forms of furnace struc 40 of repose of the particular material being treated
openings.
I
v
'
tures involving the invention.
'
'
The invention
consists in such novel methods and combinations
of method steps as are disclosed herein and also
such novel features and combinations of parts as
may be shown and described in‘ connection with 45
the furnace apparatus herein disclosed.
In the drawing:
Fig. 1 is a vertical sectional view of a furnace
embodying the invention in one of its preferred
forms; and
Fig. 2 is a similar view showing upper and low
er portions of another form of furnaceembody
ing the invention. ~
is reached. Thereupon further material which
falls on this ledge will roll or slide down over the
surface of the accumulations, to fall through the
opening 2'! at its periphery and thereby cause a
falling stream of generally cylindrical cross sec
tion in the chamber l2. At the side walls of this
chamber a plurality of oil burners or other com
bustion apparatus as at 28 may be arranged to
project‘ ?ames into the falling stream of parti
60 ‘cles, and the resulting gaseous products of com
bustion will pass countercurrent with the mate
rial through opening 2‘! into and up through
chamber II as above described.
_
The furnace as shown in Fig. 1 may comprise
‘ The bottom of chamber I! may comprise a
an outer cylindrical wall ID of suitable brick con 5 stationary hearth as at 20 having a plurality of
2412,0157
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3
peripheral discharge ports as at 30. The mate
rial as it falls on‘ this hearth will form a gener
ally conical pile as at 29' and when the sides of
.this pile reach the angle corresponding to the
natural angle of repose of the material being _,
treated, then subsequent falling material will roll
or slide down along the sides of the pile for dis
charge through the ports 30. From these ports
the ore feeding disc 20' may be stationary and
the feed or inlet pipe 55 may be connected with
a device such as a blower 58 whereby the mate
rial to be treated is carried into the furnace by
air or gas injection instead; of by the mechani
' cal feeding means of Fig. 1. ‘ .
In the lower portion of the furnace, as shown
in the embodiment of Fig. 2, the zone 13’ is con
structed without the rabbling structure present
the material may fall onto a lower stationary 10 in Fig. 1. Instead, the material dropping through
hearth as at 3i, over which it. may be agitated,
ports 30', falls down along the furnace walls
rabbled and stirred while being advanced toward
through ?ames’ from burners as at 45’,,onto an
a central discharge port as at 32. The agitating
inverted conical ledge 60 forming a part of the
may be accomplished by rotary rabbling struc
bottom of the furnace. On the ledge 63 some of _
ture such as used in furnaces well known under
the material may accumulate until its natural
the trade name “Herresho?."
This rabbling structure may for example com
angle of repose is reached, whereupon further
material will slide and roll down and out the ‘
prise a central rotatable shaft as at 33 mounted
discharge port 6 I. If desired, any suitable known
atits lower end within suitable bearings con
means may be provided at the discharge outlet
tained within housing structures shown at 34, 20 8! to regulate the flow .therethrough.
35, and adapted to be rotated as by gears'36.
The arrangement as provided in the upper
Rabble arms as at 31 may extend from the cen
tral shaft out over the hearth 3| at various angu
lar positions for carrying rabble teeth as at 38.
Theseteeth may be arranged in accordance with‘
known practice'at' angles such that the layer of
material on- the hearth is periodically agitated
and advanced inwardly of the hearth toward the
discharge port 32.
I
If the furnace includes a further chamber as
at H, a bottom hearth as at 40 may be provided
and accompanied by similar rabble arms with
teeth as at 31', the teeth here being arranged
at angles to advance the material outwardly of .
hearth 40 to a discharge port 4| connected to
chambers or zones as at H or II’ is particularly
advantageous for a number of reasons. The loca
tion and'arrangement of the feeding device is
such that as the material is introduced into the
furnace, it is forcefully distributed ?rst outward
ly in somewhat tangential and radial directions,
generally horizontally and somewhat down
wardly through the uprising streams of gas for
uniform initial heating. As the particles strike
the furnace walls in the upper zone, any lumps
of substantial size will bebroken up and the
particles will be de?ected to some extent out into
the uprising gas as they falldown to the ledge
any suitable known type of cooling device as at 35 structure 28. The generally globular formation.
assumed by the distributed falling particles in
42 positioned beneath the furnace.
this ‘chamber, makes possible a large internal
The rabbling structure may be internally cooled
in accordance with known practice by streams
of cooling air admitted for example to the base
‘space within which the rising hot gases may swirl
around‘ to insure effective and repeated contact
with all the particles.‘ Then as the particles roll
of the shaft as through a conduit 43. If desired, 40 or fall along the ledge 23, they will be maintained
a part of the cooling air may be discharged onto
in contact with the gas for a longer period than
the material on hearth 40 through rabble arm,
if they were permitted to fall directly onto hearth
openings as at 44. These openings may be con
29. Furthermore, the ledge directs the particles
structed for example in accordance with those 45 inwardly 50 that as some fall through the open
disclosed in patent to Connolly, No. 2,302,841,
ing 21, intimate contact with the constricted ris
granted November 24, 1942. Further amounts of
ing gas stream is insured and the rising gas
the cooling air if desired may be discharged
stream in this restricted opening retards the fall
through openings as at 44’ formed directly in the
of the particles to some extent.
central shaft 33 preferably at a point just be—
The cylindrical formation which the distrib
neath the hearth discharge port 32.
uted falling particles assume- in chamber I2 is
If desired, additional oil burners may be pro
well adapted to insure many possibilities of con
vided as at 35 to direct ?ames into the chamber
tact with the hot gases coming from the sides of
l3. The gaseous products of combustion in
this chamber as such gases on their way up to
chamber i3 may be allowed to pass up through
the opening 21, ‘pass through the cylindrical for
ports 30 in hearth'23 to provide all or a part of 55 mation of particles. Furthermore, the particles
the heat in the upper zones.
~
as they fall from around the periphery of open
In addition to the air introduced in chamber
ing 21, are well distributed as they fall on the
ll through rabble arm openings 44, further cool- central part of the conical pile 23’, so that non
ing air if desired may be introduced as through
uniform feeding -orv clogging at the ports "is
an inlet 43 having an adjustable damper as 50 avoided. Provision of a ‘conical pile of the ma
shown, and connected to inletports as at 43
terial on hearth 28 provides a surface over'which
positioned around the walls of chamber ll,
the. particles can again roll or. slide down with
In the form of construction shown in Fig. 2.
retarded motion in the presence of the hot gases,
the upper chamber li' may have a top wall as'at 5:, to the discharge ports 33. Since the natural angle
30 formed with a plurality of peripheral gas dis
of repose of the material of pile 23' will auto
charge ports as at ll, opening into a'chamber
matically vary. depending upon the fineness and
32 within the top of the furnace‘ and from which
character of the material, generally unifonn
the gases may be withdrawn through‘an outlet
feeding by gravity from the sides of such pile is
53. Clean-outdoors for the chamber 32 may be
made possible without the necessity of any mov
provided as indicated at 34. > This arrangement of 70
ing parts in this zone. Furthermore, if some of
the gas cutlets may be provided to insure a more
the
materialas it falls on the pile should still be
uniform discharge of the gas from various points
in a moist or somewhat sticky condition, such
around the periphery of the upper portion of the
parts of the material will remain on this pile for
chamber H’.
7s a longer period for further heat treatment and
In the construction shown in Fig. 2, if desired
2,412,057
5
6
will not tend to roll or slide of! through the ports
30 as rapidly as the material which is dry and
?nely divided and needs no further treatment
prising a chamber having a plurality 01' super?‘
posed heating zones, rotary means for feeding
‘ and projecting the material from the upper mid
in this zone.
portion 01’ the upper zone in directions to im
. Ample provision is thus made for fairly pro CI pinge on‘ the side walls around within the upperv
longed and selective treatmentof the particles
zone, va ledge protruding inwardly from said side
in zones II and I2, without the necessity of any
walls to separate said upper‘zone from the next
moving parts in either of these chambers, except
lower zone and surrounding acentral opening
for the feed device if desired.
connecting such zones, a hearth forming the bot
The lower hearth or hearths with the rabbling
tom of said next lower zone, said hearth being
means may if desired be used either as cooling
formed with peripheral discharge ports there
hearths, or one Or more of such hearths may be
through, whereby the material may fall from
used for further roasting, in case the material is said side walls in the upper zone onto said ledge,
such that it should be subjected to more pro
thence» through said central opening to form a
longed heat treatment with agitation,
pile at‘the' middle portion of said hearth, and
While the invention has been described in de
' from which pile, material may ?ow through said
tail with respect to particular preferred exam
discharge ports, and means for projecting ?ames
ples, it will be understood by those skilled in the into the material falling onto such pile.
art after understanding the invention that vari
3. A. furnace construction for treating ?nely
ous changes and modi?cations may be made
divided material comprising a plurality of su
without departing from the spirit and scope of
perposed hearths, rotary rabbling means for agi
the invention, and it is intended therefore in the
tating and advancing material over said hearths
appended claims to cover all such changes and
in succession; means for feeding the material
modi?cations.
onto the uppermost of said hearths, comprising
What is claimed as new and desired to be se-.
another superposed stationary hearth formed
cured by Letters Patent is:
with peripheral discharge ports, walls surround
1. A furnace construction for treating free
_ ing the latter hearth to form a chamber, means
?owing masses of ?nely divided material, com
for maintaining a heated atmosphere in such
prising a chamber having a plurality of super
chamber, and means for dropping continuous
posed heating zones, means for feeding and pro 30 supplies of distributed particles of the material
jecting the material from the upper mid portion
into the chamber and onto the latter hearth to
of the upper zone in directions to impinge on the
form a substantially conical pile, whereby fur
side walls around within the upper zone, a ledge
' " ther falling material rolls and slides. down the
protruding inwardly from said side walls to sepa
sides of such pile. and through said ports.
rate said upper zone from the next lower zone 35
4. Method for roasting ?nely divided material
and surrounding a central opening connecting
which comprises causing same to fall through a
such zones, and a hearth forming the bottom of
stream of hot gas, onto a generally conical pile
said next lower zone, said hearth being formed
of the material supported on a stationary hearth
with peripheral discharge ports therethrough,
in a closed chamber and in the presence of a
whereby the material may fall from said side 40 heated atmosphere, allowing the material to then
walls in the upper zone onto said ledge, thence
roll and slide down along the sides of such pile
through said central opening to form a pile at
and fall from the periphery thereof onto a lower
the middle portion of said hearth, and from
hearth, and then stirring and advancing the ma
which pile, material may ?ow through said dis
terial as a relatively thin layer over the latter
7 charge ports.
2. A furnace construction for treating i'ree
?owing masses of ?nely divided material, com
45
hearth.
,.
.
CHARLES W. NICHOLS. _
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