close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3098120

код для вставки
July 16, 1963
3,098,] 10
T. R A. DAVEY ETAL
COOLING ARRANGEMENTS FOR MOLTEN METALS
Filed Sept. 17, 1959
2 Sheets-Sheet l
.6
' I
L
July 16, 1963
T. R. A. DAVEY ETAL
3,098,110
COOLING ARRANGEMENTS FOR MOLTEN METALS
Filed Sept. 17, 1959
Z6
r
2 Sheets-Sheet 2
United States Patent
TQC
3,'h98,1 l0
Patented July 16, 1963
1
2
3,098,110
FIGURE 3 is a horizontal section taken on the section
line 3—--3 of FIGURE 2.
COOLING ARRANGEMENTS FDR
FIGURE 4 shows part of FIGURE 2 showing a modi
MOLTEN METALS
?cation.
Thomas Ronald Albert Davey, Bristol, and Walter Lind
say Linton, Langford, near Bristol, England, assiguors 5
The gaseous product of the zinc-smelting operation
to Metallurgical Processes Limited, Nassau, Bahamas,
and The National Smelling Company Limited, London,
England, doing business together as Metallurgical De
velopment Company, Nassau, Bahamas
flows through the condenser 5 in counter-current with
the molten lead circulating therethrough. The molten
lead with its burden of condensed zinc is Withdrawn from
Filed Sept. 17, 1959, Ser. No. 840,600
Claims priority, application Great Britain (lot. 17, 1958
5 Claims. (Cl. 266-15)
the gas intake end of the condenser into a sump or the
ing successively through the condenser, a cooling device,
that a protective layer 13 of flux such as zinc ammonium
like 6. A pump 7 transfers the zinc-rich molten lead
from the sump through a pipe 8 into the cooling tank
9, where the molten metal mixture is cooled by contact
This invention relates to the cooling of the zinc-con
with the rotating drums Ill, and gradually separates into
taining molten lead in zinc vapor condensing systems in
a layer of zinc-containing lead 11 (see FIGURE 2) with
which zinc vapor is condensed in molten lead circulat 15 a lead-containing zinc layer 12 ?oating on top, and above
a settling zone and back to the condenser, and has for its
chloride. The cooled molten metal mixture is deliver
object the provision of certain improvements in cooling
ed to a settling tank 14 from whence the ?oating layer
the zinc-containing molten lead withdrawn from the con
of zinc is removed by over?ow into a zinc holding tank
denser.
20 15. The de~zinced molten lead is returned through a
In the smelting of zinciferous materials for the produc
pipe 16 to the gas outlet end of the condenser 5. The
tion of metallic zinc, as for example in a zinc-smelting
cooling tank 9 is surrounded by an outer case 17, and
blast furnace, the zinc vapor in the smelting gases is com
gas burners or the like 18 are provided at convenient
monly condensed in molten lead circulating through the
positions between the tank 9 and the outer case 17 to
condenser in countercurrent with the ?ow therethrough 25 heat the space therebetween, whenever it is necessary to
of the gases. The molten lead with its burden of con
densed zinc passes from the condenser to a cooling de
supply external heat to the tank in order to prevent un
due cooling of the circulating molten lead, more particu
larly when the condenser is temporarily out of action.
Referring to FIGURE 2, each cooling drum 10 is cy
zinc. The molten metal mixture then passes to a settling 30 lindroid in shape and preferably made of sheet steel.
vice where the temperature is lowered to promote the
separation of zinc from the molten mixture of lead and
zone or tank where molten metallic zinc is removed by
The drum is mounted to rotate about a generally verti~
over?ow, continuously or periodically, and the residual
cal axis, and its circular top is of slightly greater di
molten lead, still containing some zinc, is returned to the
ameter than its bottom. An upright tubular extension
condenser where the cycle is repeated. The present in
neck 19 communicates with the interior of the drum
vention is concerned with apparatus for facilitating the 35 through a circular hole in the top thereof, the exten
cooling of the zinc-rich molten lead passing from the
sions being welded or otherwise suitably secured to the
condenser to the settling zone.
top of the drum with the vertical axes of the drum and
In accordance with the present invention the cooling
extension coincident. The extension 19 is rotatably sup
arrangement for the zinc-rich molten lead comprises a
ported in bearings 20, thus serving as the shaft for the
40
suitable cooling chamber, such as a trough or tank,
rotatable drum. The vertical thrust of the water-?lled
through which the molten metal mixture passes and which
drum and extension upon the bearings 20 is practically
is provided with one or more interiorly cooled rotating
negligible because of the buoyancy imparted to the
drums, or the like, arranged to dip into the molten metal
drum by its almost complete immersion in the molten
mixture for extracting heat therefrom. Each drum is in
metal. The drum and extension are adapted to be ro
teriorly cooled by passing a cooling fluid therethrough, 45 tated by a powerdriven belt 21 operatively engaging a
the ?ow of cooling ?uid being coordinated with the speed
pulley 22 secured to. the extension.
of rotation of the drum to inhibit solidi?cation of lead
on the surface of the drum. The cooling drum is gen
A suitably supported stationary pipe 23 is positioned
inside the tubular extension 19. The top of the pipe
erally cylindroid in shape and is mounted for rotation in
is connected to a source of cooling ?uid (not shown),
a generally vertical axis. The drum is adapted to be 50 and its lower end terminates in a discharge nozzle 24.
substantially completely immersed, or immersed for the
The upper end of the rotatable extension 19 has a tongue
greater part of its length, in the zinc-containing molten
groove sealing connection 25 with a stationary over?ow
lead in the cooling chamber or tank, and the drum is
trough 26 having a lateral discharge outlet 27 for spent
provided with stationary internal ba?les that tend to pre
cooling ?uid. Before the drum is closed, a series of cir
55
vent rotation of the body of cooling ?uid within the
cumferentially spaced vertical baffles or ‘blades 28 are
drum due to rotation of the drum.
. Preferably means are also provided for preventing the
secured to the lower end of the stationary pipe 23 so as
to be within the drum when closed.
molten metal which is to be cooled, from being agitated
Externally to the rotating drum is arranged a concentric
or rotated by the drum, said means, for example, con
circular skirt 29 which dips into the metal and from which
sisting of a circular skirt which dips into the metal and 60 depend a number of radial vertical baffles or blades 30.
from which depend a number of vertical ba?les or blades.
The circular skirt 29 is securely attached to a structure
The invention will be best understood from the follow
32 which also supports the bearings 20.
ing description taken in conjunction with the accom
panying drawings, in which:
The drum (or drums) 10 dips into the molten metal
mixture in the cooling tank 9 with the top of the drum
FIGURE 1 is a diagrammatic plan of a zinc vapor 65 slightly above the surface of the flux layer 13-, as indi
condensing system embodying the invention, the upper
portion of the supporting structure of each of the cooling
cated in FlGURE 2.
The drum is thus immersed for
the greater part of its length in the molten metal mixture
drums being cut off along line 1-1 of FIG. 2 in order
in the cooling tank. Water, ‘or other suitable cooling ?uid,
to show the cooling drums more clearly,
is
delivered to the drum through the pipe 23 and is dis
FIGURE 2 is a vertical section taken on the section 70 charged over the seal 25 into the trough 26, and is cus
line 2—2 of FIGURE 1, and
tomarily returned to the source of cooling ?uid for re
3,098,110
3
use. The drum is rotated at a speed sufficient to prevent
solidi?cation and adhesion of lead on the surface of the
4
drum, said drum being adapted to be substantially com
pletely immersed in the zinc-containing molten lead in
the cooling tank, an upright tubular extension secured
drum, other conditions of cooling being constant. Such
to the drum and communicating with the interior thereof
other conditions affecting the cooling action include the
initial temperature of the cooling ?uid and the rate of ?ow GI through a hole in the top of the drum, means for intro
ducing cooling ?uid into the drum and for withdrawing
of cooling ?uid through the drum. Since these other con
cooling ?uid therefrom through said tubular extension,
ditions are in practice more or less ?xed by the source
and rate of supply of the cooling ?uid and the dimen
means for rotating the tubular extension and the drum
secured thereto, means for preventing substantial rotation
sions of the drum and its appurtenances, the cooling
action is conveniently controlled and regulated by ad 10 of cooling ?uid in the drum, caused by rotation of the
drum, comprising at least one radially-disposed stationary
justing the speed of rotation of the drum.
baf?e positioned within the rotatable cooling drum, and
In operation, the water (or other cooling ?uid) cir
culates as shown by the arrows in FIGURE 2, and is
prevented from rotating with the drum so that the rotat
ing wall of the drum has a high velocity with respect to
both the molten metal and the cooling ?uid, thus ensuring
high heat transfer rates. Rotation of the drum about
a generally vertical axis permits the circulating cooling
?uid to completely ?ll the drum and practically complete
immersion of the drum beneath the surface of the ?ux
layer thereby attaining optimum heat transmission be
tween the surface of the drum and the cooling ?uid. The
?ux layer prevents the formation of aerated dross, The
stationary vertical baffles within the drum minimize rota
tion of the cooling ?uid with the drum. Rapid circula
tion of the cooling ?uid is provided in planes passing
through the axis of rotation of the drum. This also im
proves the heat transmission between the drum and the
cooling ?uid. Good circulation of cooling ?uid over the
end of the drum that is submerged in the'molten metal
avoids localized steam formation which results in a ham
mering effect.
The cooling action of the drum is illustrated by this
example:
With an eight-inch outside diameter drum of 1?t-inch
wall thickness immersed about 6 inches in the lead (sur
face area 1.4 sq. ft.) and rotated at 300 r.p.m. and with
20-30 gal./min. water at about 15° C. initially, passed
into the drum through a two-inch diameter pipe, cooling
of 600,000‘ to 250,000 B.t.u. per hour is possible, accord- '
ing to depth of accretion on the drum.
The slightly conical form of the drum permits ready
periodical removal of accretions which are largely zinc
arsenide where the zinc vapor is condensed in a lead
splash condenser associated with a zinc smelting blast
furnace.
Any solidi?cation of lead on the drum surface indi
cates that too great arti?cial cooling of the molten metal
is taking place in the immediate vicinity of the drum with
attendant danger of unduly cooling the entire bath of
molten metal in the cooling tank. In an elongated cool
ing tank or trough, cooling of the molten metal is progres
sive from the inlet to the outlet end of the tank, and in
practice the overall cooling action will normally reduce
the temperature of the molten metal from about 550°
C. at the inlet end of the tank to about 450° C. at the
outlet end of the tank. In other words, the arti?cial
cooling action of the drum should be so controlled and
regulated that the molten metal in the tank should not be
cooled below about 450° C.
FIGURE 4 shows the drum immersed in the molten
metal. In this method of operation, the neck and upper
surface of the drum are provided with insulation 31 to
prevent any accretion forming at these points.
65
We claim:
1. In the combination of a condenser in which zinc
vapor is condensed in molten lead that is circulated suc
cessively through the condenser, through a cooling tank
having cooling means for cooling the zinc-containing
molten lead, through a settling zone where molten metallic 70
zinc is separated and removed, the molten lead then being
returned to the condenser, the improvement in said cool
ing means which comprises at least one generally cylin
droid cooling drum rotatably mounted for rotation about
the generally vertically disposed longitudinal axis of the 75
means for preventing substantial rotation of the zinc
containing molten lead in the cooling tank immediately
surrounding the rotatable cooling drum comprising at
least one bat?e extending in a direction generally verti
cally and radially with respect to said drum.
2. The apparatus according to claim 1 in which the
means for introducing cooling ?uid into the rotatable
cooling drum is a vertically disposed stationary ?uid
supply pipe positioned within the tubular extension of
the drum, and in which the circumferentially spaced sta
tionary bal?es within the drum are secured to the lower
portion of the cooling ?uid supply pipe.
3. The apparatus according to claim 1 in which the
top of the cooling drum and the portion of the tubular
extension adjacent thereto are provided with a layer of
insulating material whereby the formation of accretions
of solidi?ed metal at this point is prevented.
4. The apparatus according to claim 1 in which means
are provided for applying external heat to the cooling
tank.
5. In the combination of a condenser in which zinc
vapor is condensed in molten lead that is circulated suc
cessively through the condenser, through a cooling tank
having cooling means for cooling the zinc-containing
molten lead, through a settling zone where molten metal
lic zinc is separated and removed, the molten lead then
being returned to the condenser, the improvement in said
cooling means which comprises at least one generally
cylindroid cooling drum rotatably mounted for rotation
about the generally vertically disposed longitudinal axis
of the drum, said drum being adapted to be substantially
completely immersed in the zinc-containing molten lead
in the cooling tank, an upright tubular extension secured
to the drum and communicating with the interior thereof
through a hole in the top of the drum, means for intro
ducing cooling ?uid into the drum and for withdrawing
cooling ?uid therefrom through said tubular extension,
means for rotating the tubular extension and the drum
secured thereto, and means for preventing substantial ro
tation of cooling ?uid in the drum, caused by rotation
of the drum, comprising at least one radially-disposed
stationary baffle positioned within the rotatable cooling
drum and having a substantially planar face facing coun
tercurrent to the direction of rotation of said drum.
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,018,266
2,351,489
2,439,216
2,734,819
Kemmer _____________ __ Oct. 22,
Cooper ______________ __ June 13,
McLellan _____________ __ Apr. 6,
Williams _____________ __ Feb. 14,
1935
1944
1948
1956
2,801,162
2,866,702
2,871,007
2,956,871
Keeping ______________ __ July
Batutis et al ___________ __ Dec.
Derham et al __________ __ Jan.
Curnow et al ___________ __ Oct.
30,
30,
15,
18,
1957
1958
1960
1960
Belgium ______________ __ Ian. 31,
Belgium ______________ __ Jan. 31,
Great Britain __________ __ May 8,
Great Britain __________ __ May 6,
1958
1958
1957
1959
FOREIGN PATENTS
563,916
563,917
774,269
812,837
Документ
Категория
Без категории
Просмотров
0
Размер файла
435 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа