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Патент USA US2136174

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Noir. 8, 19378.
-
M. VOGEL-JORGENSEN
2,135,174
KILN‘
Filed July 23, 1937
gjm áms"ímf
ATTORNEYS
2,136,174
UNITED STATES PATENT oEFicE
Patented Nov. 8, 1938
2,136,174
KILN
Mikael Vogel-Jorgensen, Frederiksberg, near
Copenhagen, Denmark, assignor to F.
Smidth & Co., New York, N. Y., a corporation
of New Jersey
Application July 23, 1937, Serial No. 155,151
In Great Britain August 6, 1936
9 claims. >(ci. 263-32)
This invention relates to rotary kilns heated
by a llame directed axially along the kiln from
the outlet end in countercurrent to the iiow of
material through the kiln and supported by sec
5 ondary air for combustion admitted through one
or more openings. More particularly, the inven
tion is concerned with a novel kiln of the type
referred to which includes means by which the
admission of secondary air into the kiln is con
10 trolled and the ingress of air in proximity to the
material in the kiln is prevented or reduced.
In rotary kilns in which combustion is sup
ported by the admission of secondary air, it is
important to keep at a minimum the amount
15 of dust arising Within the kiln during operation,
since the presence of dust in the burning zone
impairs the vision of the operator who controls
the supply of fuel and material to the kiln. ‘In
certain industries, the nature of the raw materials
20 being burned is such as to aggravate the dust
conditions within the kiln, an example of such
material being alumina, which, when it reaches
the burning zone, contains very ñne particles
readily picked up by the secondary air. The iiow
25
of the air through the kiln may carry such fine
particles back to the outlet through which the
waste gases issue, and the likelihood of such
entrainment is increased when the secondary
air is admitted into the kiln in such a way as to
30
ñow close to the surface of the material in the
kiln.
The present invention is, accordingly, directed
to the provision of a kiln in which entrainment
of fine material by the secondary air is avoided
35
or minimized, and for this purpose, the kiln is
provided with means, preferably operating auto
matically as the kiln rotates, to control the ad
mission of secondary air and to admit such air
only at a distance from the material.
The in
40 vention may be embodied in rotary kilns of
various kinds, but since it aiîords special advan
tages in connection with kilns having a series of
cooling drums or tubes disposed in a planetary
arrangement at the outlet end, a kiln of this
45 speciñc type, in which the invention is employed,
will be illustrated and described in detail for
purposes of explanation. It is to be understood,
however. and Will be apparent that the utility of
the invention is not limited to rotary kilns of
any particular construction.
For a better understanding of the invention,
reference may be had to the accompanying draw
ing, in which
Figure l is a longitudinal sectional view, with
5 Ul parts shown in elevation, of a new kiln provided
with cooling tubes;
Figure 2 is a diagrammatic perspective view
showing the mode of operation of the air control
B0 mechanism employed in the kiln of Figure l;
Figure 3 is'a fragmentary perspective view of
a modified control means: and
Figure 4 is a diagrammatic end elevation of
another form of the control means.
In the construction illustrated in Figure 1,
the kiln I0 is supported in the usual manner
by tires II resting on rollers I2 and rotated by
the 4usual driving means, and the shell of the
kiln has the customary refractory lining I3
which is of increased thickness in the burning 10
zone, as indicated at I4. A plurality of openings
I5 are formed in the kiln beyond the ring I4 to
permit the discharge of the smaller pieces or
lumps of material which pass through the open
ings into cooling drums or tubes I6. The pieces 15
of material which are too large to enter the
openings I5 pass into an extension I1 of the kiln,
the lining of which is thickened to provide a ring
I8 which retains such pieces until it is desired to
remove them. The end of the kiln is provided 20
with a closing hood I9 through which a burner
20 projects, the burner serving to direct a flame
axially into the kiln, and the hood is provided
with a door 2| through which the larger pieces
of material may be removed. The kiln is pro 25
vided with the usual peep holes and other fea
tures commonly employed in kilns of this con
struction.
The cooling tubes are of the usual construc
tion and are provided at their ends 22 with 30
closures having openings 23 through which ma
terial is discharged and air admitted. The open
ings are so placed that they lie near the bottoms
of the tubes when the latter are in lowermost
position, and pivotally mounted on the closure 35
of each tube is a damper 24 of sector shape and‘
of suiücient size to close the opening. During
rotation of the kiln, the dampers swing freely
ón their pivots and alternately open and close the
openings 23, the arrangement being such that 40
ingress of air through each tube and into the kiln
is prevented at a time when the passage I5
leading from the tube into the kiln lies beneath
the material within the kiln or close to the sur
face of the material.
45
In some instances, it may be desirable to vary
the timing of the opening and closing of the
dampers, and for this purpose, the constructions
shown in Figures 3 and 4 may be employed. In
the Figure 3 construction, each damper is pro 50
vided With a ring 25 which extends about the
end of the tube I6 and a weight 21 is adjustably
mounted on the ring. By shifting the weight
along the ring to different positions, the action
of the damper in opening and closing its opening 55
23 may be varied as desired. In the construction
illustrated, the tube I6 is provided with an air
inlet opening 23 at its end, and another opening
28 through its wall through which the cooled
material may be discharged. The damper 2l is, 60
2
aiscnn
accordingly, provided with an extension 29 along
the outside of the tube, which serves to control
the opening 28. With the construction described,
the admission of air is not reduced by the outflow'
of material during the discharging period, but ,l
both openings are closed at the same time to
prevent a dust condition from occurring in the
kiln.
In the Figure 4 construction, the dampers 30
pivotally mounted on the ends of the tubes to
control the openings 3i are provided with ex
tensions 33 carrying rollers 3l, which engage
a cam rail 35, mounted adjacent to the series
of dampers. As the kiln rotates, the rail swings
15 the dampers to open position and holds them in
open position longer than would be the case il
the dampers were controlled by gravity alone.
This arrangement ls permissible in the kiln illus
trated by reason of the slope of the material, as
20 indicated at 36, and the use of the cam means
insures a greater supply of secondary air than
in the constructions in‘which the dampers are
operated by gravity only.
I claim:
25
1. The combination with a rotary kiln having
an end at which the material discharges, oi' a
burner for directing a flame axially into the kiln
at said end, the kiln having a plurality of open
ings adjacent said end for the admission oi' air
30 for combustion, and means operating automati
cally as the kiln rotates to permit the ingress
of air through said openings during the major
part of the rotation of the kiln and to prevent
admission of air in proximity to the material
35 Within the kiln.
2. The combination with a rotary kiln having
an end at which the material discharges, of a
burner for directing a ñame axially into the kiln
at said end, the kiln having a plurality _of open
40 ings adjacent said end for the admission of air
for combustion, and dampers for the individual
openings operating automatically as the kiln ro
tates to keep said openings unclosed during the
major part of the rotation of the kiln to permit
45 the ingress of air therethrough and to close said
openings during the remaining part of the rota
tion of the kiln to prevent admission of air to the`
kiln in proximity to the material within the kiln.
3. The combination with a, rotary kiln having
50 an end at which the material discharges, of a
to permit ingress of air during the major part
of the rotation of the kiln.
5. The combination with a rotary kiln, 0i.' a
plurality of' cooling tubes arranged about the kiln
at the discharge end thereof in a circumferential
series and receiving material discharging from
the kiln, a burner for directing a name axially
into the kiln at said discharge end, air for com.
bustion being admitted into the kiln through said
tubes, and means associated with the tubes to
permit the ingress of air through the tubes dur
ing the major part of the rotation of the kiln
and to prevent admission of air to the kiln in
proximity to the material within the kun.
6. The combination with a rotary kiln having
an end at which the material discharges, of a
burner for directing a flame axially into the kiln
at said end, a plurality of tubes adjacent said
end receiving material from the kiln and admit
ting air for combustion into the kiln, and means
for controlling the admission of air into the kiln
through said tubes including dampers for the ln
div'idual tubes mounted for free movement as
the kiln rotates and preventing ingress of air
into the kiln in proximity to the material therein.
7. The combination with a rotary kiln having
an end at which the material discharges, of a
burner directing a` iiame axially into the kiln
at said end, a plurality of cooling tubes mounted
adjacent said end and in communication with the
interior of the kiln to receive material discharg
ing therefrom and to admit airior combustion,
each tube having a discharge opening, dampers
mounted on the tubes to control admission of air
through the tube discharge openings, and cam
means mounted adjacent the kiln and control
ling the dampers to permit ingress of air through
said openings during the major part of the rota
tion of the kiln, said dampers preventing ingress
of air into the kiln in proximity to the material
therein.
8. The combination with a rotary kiln having
an end at which the material discharges, of a
burner directing a flame axially into the kiln at
said end, a plurality of cooling tubes mounted
adjacent said end and in communication with
the interior of the kiln to receive material dis
charging therefrom and to admit air for com
bustion, each tube having an opening at its end
kiln at said end, the kiln having a series of open
and an opening in its wall for discharge of ma
terial and admission of air, and dampers for the
individual tubes for controlling both openings
ings adjacent said end for admission of air for
thereof, said dampers being moved automatically
combustion, and pivotally mounted dampers for
as the kiln rotates to prevent ingress of air into
the kiln in proximity to the material therein.
9. The combination of a rotary kiln having an
burner for directinga flame axially into the
55 the individual openings moving as the kiln ro
tates to keep said openings unclosed during the
major part of the rotation of the kiln to permit
the ingress of air therethrough and to close said
openings during the remaining part of the rota
60 tion of the kiln to prevent ingress of air through
the openings in proximity to the material in the
kiln.
4. The combination with a rotary kiln having
an end at which the material discharges, oi a
65 burner for directing a flame axially into the kiln
at said end, the kiln having a series of openings
adjacent said end for admission of air for com
bustion, movable dampers i'or the individual
openings,
and controlling means for the dampers
70
operating as the kiln rotates to cause the damp
ers to prevent ingress of air in proximity to the
material in the kiln and to cause the dampers
end at which the material discharges, of a burner
for directing a flame axially into the kiln at
said end, the kiln having a plurality of open
ings adjacent said end through which air may
be admitted and supplied to the interior of the
kiln at a plurality of circumferentially spaced
delivery points, and means operating automati
cally as the kiln rotates to close each of said
openings to prevent the delivery of air at the cor
responding delivery point in the kiln during the
time that such delivery point lies beneath the ma
terial within the kiln or close to the surface of
the material and to keep each oi' said openings
unclosed during the time that the correspond
ing delivery point traverses the remaining part
oi' its travel.
i
MIKAEL VQGEL-JORGENSEN.
65
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