Water-air seal for converter hood

A seal is provided to prevent gas flow through the opening in the converter enclosure that accommodates the converted hood and the annular skirt that is telescopically movable thereon. The seal comprises a fixed ring on the enclosure and a movable ring attached to the skirt. The latter contains a liquid body for sealing purposes. The configuration of the rings is such that they cooperate to define a labyrinth to prevent kish accumulation in the liquid seal. Pressurized air can be supplied to augment the liquid seal.

BACKGROUND 
When, during the blowing period of a steel refining process, oxygen is 
introduced into a steelmaking converter, of either the top- or 
bottom-blown type, large quantities of gaseous effluent are generated by 
the chemical reaction between the oxygen and the high temperature molten 
metal in the converter. The effluent is discharged from the mouth of the 
converter into a gas collecting hood which conducts the same to gas 
cleaning apparatus for appropriate processing prior to its being 
discharged to the atmosphere. Gas-collecting hoods of the type involved 
are customarily provided with a sliding skirt that is telescopically 
mounted on the end of the hood adjacent the converter mouth and vertically 
movable with respect to the hood end from a lower position in which the 
skirt abuts the converter to seal the junction between the converter and 
the hood and a raised position whereby air for combustion from the 
effluent gas can be admitted to the hood interior. 
Part of the gas containment structure of a converter installation of the 
described type includes a vessel enclosure through the upper wall of which 
the hood must extend in order to establish gas communication between the 
converter and the hood interior. In the past, the opening provided in the 
enclosure for penetration of the hood had to provide sufficient clearance 
in order to accommodate the movable skirt and the mechanism for operating 
the same. Although this clearance space was maintained as small as 
possible, it nonetheless provided ample opportunity for egress of the 
effluent gases from the converter especially during periods of high 
reaction activity thus permitting unacceptably large amounts of gas to 
leak from the system into the surrounding atmosphere. 
It is to the improvement of such gas containment apparatus therefore that 
the present invention is directed. 
SUMMARY 
According to the present invention, there is provided apparatus including 
an apertured vessel within which gases are generated, gas confining means 
having an opening spaced above the vessel aperture, an annular skirt 
concentrically spaced from the edge of said opening and movable 
therewithin, and means for sealing the concentric space between said skirt 
and said edge, comprising a first annular body disposed in fixed relation 
to the edge of said opening and including plate means cooperating to 
define a pair of concentric spaces within said body, the ends of the 
spaces adjacent said converter aperture being open and those remote 
therefrom being closed, a second annular body movable with respect to said 
first body including concentrically spaced plates defining a receptacle 
extending into said spaces in said first body means for supplying liquid 
to said receptacle, and means for moving said second body in relation to 
said first body coincident with movement of said skirt. 
It is accordingly a principal object of the present invention to provide 
apparatus for preventing the discharge of gaseous effluent from a oxygen 
steelmaking converter installation into the atmosphere. 
It is another object of the invention to provide means for effectively 
sealing against deleterious effluent gas leakage the clearance space 
between the gas enclosure opening and the hood required to accommodate 
movement of the hood skirt between its lowered and raised positions. 
Yet another object of the invention is to provide an effluent gas seal 
between the movable skirt and the gas enclosure that can accommodate 
movement of the skirt while maintaining the integrity of the seal. 
Still another object of the invention is to provide an effluent gas seal of 
the described type in which the liquid seal can be supplemented by the 
injection of air under pressure. 
For a better understanding of the invention, its operating advantages and 
the specific objectives obtained by its use, reference should be made to 
the accompanying drawings and description which relate to a preferred 
embodiment thereof.

DESCRIPTION OF PREFERRED EMBODIMENT 
In FIG. 1 of the drawing, there is illustrated a steel refining 
organization including a converter vessel 10 in which molten metal is 
refined by the injection of oxygen and other refining elements and a hood 
12 arranged to conduct the gases generated in the vessel during the 
refining process to a point of ultimate discharge, all as is well known in 
the art. Also well known is the fact that certain gas-processing steps, 
such as complete or partial combustion of the gases as hereinafter 
described, are generally conducted in the hood 12 prior to discharge of 
the gases to the atmosphere. 
The converter vessel 10, only the upper portion of which is shown in the 
drawing figure, is here illustrated as being of the type in which 
bottom-blown steelmaking processes are performed, although it should be 
understood that the invention described herein is equally applicable to 
organizations in which top blowing of oxygen occurs. The vessel 10 is 
provided with an upwardly facing mouth 14 through which gases generated 
within the vessel interior exit therefrom. Located above the vessel mount 
14, in gas-receiving relation thereto, is the inlet opening 16 to the hood 
12. The hood 12 is defined by polygonally arranged walls formed of 
parallel tubes 18 connected for the through flow of cooling liquid by 
inlet and outlet ring headers 20 and 21, respectively. The hood 12 is 
severable at a joint, indicating at 24, to enable the section 12a that 
overlies the vessel 10 to be laterally removed to permit workman access to 
the vessel interior. For this reason, the hood section 12a is fixedly 
suspended by elastic suspension means 26 from a carriage 28 having wheels 
30 running on rails 32 carried by structural members 34. 
The converter vessel 10 is enclosed within a housing 36, the top wall 38 of 
which is disposed at about the level of the space between the vessel mouth 
14 and the lower end of the hood 12. The wall 38 of housing 36 is provided 
with a through opening 40 to accommodate the hood 12 and the skirt 
assembly 42. 
Within the peripheral edge of opening 40 and surrounding the space between 
the vessel mouth 14 and the hood inlet opening 16 is an annular vertically 
movable skirt assembly 42 consisting of skirt 44 and a liquid seal 
structure 46, the details of neither of which form part of the present 
invention. The skirt 44 is defined by a plurality of hairpin tubes 48 that 
are disposed in parallel, side-by-side relation and whose opposite ends 
are connected between headers 50 and 52 for the circulation of coolant 
fluid therethrough. The skirt 44 is concentrically spaced at 54 from the 
exterior of the hood 12 to accommodate relative vertical movement between 
the two members. The seal structure 46 comprises an annular trough 56 
containing a body of liquid and a baffle plate 58, the lower end of which 
is immersed in the liquid body to effect a seal and thereby prevent gas 
leakage through the space 54. Trough 56 is fixed to the skirt 44 by an 
annular support structure 60 which spacedly encircles the hood 12. Baffle 
plate 58, on the other hand, is stationary and depends from an annular 
seal plate 62 that is attached to inlet supply header 20 about one edge 
and to the exterior wall of the hood 12. The described seal structure is 
effective to accommodate vertical movement of the skirt assembly 42 while 
maintaining the integrity of the gas seal about space 54. 
The skirt assembly 42 is vertically movable by means of hydraulically 
operated lifters 64, only one of a plurality of which is shown, between a 
lower position in which the bottom of skirt 44 abuts the top edge of 
vessel 10 about its mouth 14 and a raised position that permits entry of 
air from within the interior of housing 36 into the hood 12 where the same 
is employed for the complete or partial combustion of the combustible 
components of the effluent gases, such as carbon monoxide. Regulation of 
the influx of air into the hood is achieved by adjusting the position of 
the skirt 44 through operation of the lifters 64, all as is well known in 
the art. 
According to the present invention, means are provided to positively seal 
the opening 40 in the converter housing 36 against the leakage of effluent 
gases while, at the same time, accommodating vertical movement of the 
skirt assembly 42. The sealing arrangement comprises a fixed ring 70 
formed as an annular body having three concentrically spaced plates 72, 74 
and 76 that are joined at their upper ends by annular end closure 78. The 
plates 72, 74 and 76 cooperate to define a pair of downwardly open 
concentric spaces, 80 and 82 respectively. The fixed ring 70 is detachably 
secured to the top wall 38 of housing 36 about the opening 40 by means of 
threaded connectors (not shown), or the like, that pass through aligned 
openings in the housing and in an annular flange 84 which extends 
outwardly from the exterior surface of the radially outermost plate 72. 
Cooperating with the fixed ring 70 is a movable ring 86 formed as an 
annular body having two plates 88 and 90 that are upstanding from an 
annular bottom closure 92. Plates 88 and 90 are concentrically spaced with 
respect to each other to define a liquid receptacle 94 therebetween. The 
annular plates 72, 74 and 76 on fixed ring 70 and plates 88 and 90 on 
movable ring 86 are each formed of diameters to permit plates 88 and 90 on 
the movable ring to extend into the spaces 80 and 82 in the fixed ring and 
for the intermediate plate 74 on the fixed ring to be received in the 
receptacle 94 in the movable ring. This cooperation between the plates on 
the two rings permits relative telescopic movement between the two 
members. This configuration also produces labyrinth-like passages on 
opposite sides of the liquid receptacle 94 that impedes the incursion of 
kish or other fine particulate matter into the receptacle that would 
ultimately result in sufficient particle accumulation therein to cause 
failure of the seal. 
The movable ring 86 is fixedly attached, as by means of welding, to the 
inlet supply header 50 of skirt 44 so as to effect movement of the ring 
with the skirt. Attachment of the ring 86 to header 50 is effected by 
welding the inner peripheral edge of a flange 96 that extends from the 
bottom closure 92 to the header. 
The lower end of the movable ring 70 that faces the converter mouth 14 and 
is thus exposed to radiant and convective heat from the converter is 
cooled by cooling liquid circulated in heat transfer relation to the ring 
bottom through an annular chamber 98 formed coincident with the bottom by 
subtending plates 100 and 102. To effect circulation of cooling fluid 
through the chamber 98, the chamber, as shown in FIG. 5, is provided at 
one point about its circumference with a closure partition 104. Cooling 
fluid inlet and outlet supply tubes 106 and 108 respectively, that connect 
to a source (not shown) of cooling liquid, communicate with the chamber 
each on opposite sides of, and in close relation to, the partition 104 
whereby cooling fluid is caused to flow about the annular passage from the 
inlet to the outlet. 
In the preferred embodiment of the invention, it is contemplated to supply 
seal liquid to the receptacle 94 in fixed ring 86 by connecting the same 
in fluid circulation with the trough 56 forming part of the skirt assembly 
42. The means for accomplishing this are best shown in FIGS. 5 through 6 
and comprise a transfer duct 110 connected between and movable with the 
trough 56 and the receptacle 94 in the movable ring 86. The duct 110 
communicates at its upper end with trough 56 through an opening 112 
provided in the exterior side wall thereof. The lower end of the duct 110 
communicates with the bottom of the receptacle 94 by penetrating the plate 
90. Because the opening 112 in trough 56 is above the upper edge of the 
receptacle 94 the latter will remain filled to a level that will maintain 
immersion of the intermediate plate 74 of fixed ring 70. The liquid exits 
the receptacle 94 over a wier edge 114 formed on the upper edge of the 
plate 88 into an arcuate receiving tray 116 sized to accommodate the 
liquid flow from the receptacle. A discharge lip 118 is provided on the 
exterior side wall of tray 116 for discharge of liquid to a drain 120. The 
space between the drain 120 and the receiving tray 116 is sealed against 
gas leakage by plate means forming an enclosure 122. 
The present invention contemplates supplementing the sealing effect of the 
liquid seal about the opening 40 in the converter enclosure 36 by the 
imposition of regulated amounts of seal air from a source of pressurized 
air (not shown). Thus, the end closure 78 of the fixed ring 70 is provided 
with a plurality of circumferentially spaced openings 124 that communicate 
with the space 80 between the plates 72 and 74. Connected to each opening 
124 is a feeder line 126 connecting with an air manifold 128. As a result, 
pressurized air at a head preferably not less than 2 inches of water can 
be admitted to the seal to augment the effect of the liquid seal. 
Alternatively, in the event of complete loss of sealing liquid, air at 
this pressure or at a somewhat elevated level is deemed to be sufficient 
to provide an adequate pressure seal against gas leakage. 
The described air admission means further provides a convenient device for 
introducing supplementary air for combustion to the interior of the hood 
enclosure 36 for induction into the hood during periods within which 
adequate amounts of air are not available in the enclosure to achieve the 
desired degree of effluent gas combustion in the hood. Air admitted to the 
space 80 in the fixed ring 70 will pass through the annular space between 
plate 72 in the fixed ring 70 and plate 88 in the movable ring 86 into the 
interior of the enclosure 36 from whence it can be induced into the hood 
12 for use as combustion air. 
Another ancillary advantage derived from use of the described seal 
arrangement is the facility with which exposure of the vessel mouth 14 can 
be obtained, as for example, when it is desired to rebrick the vessel 
lining or perform other maintenance tasks. To dismantle and remove the 
seal structure all that is required is to disengage the threaded 
connectors that connect the fixed ring flange 84 to the housing top wall 
38 and to thereafter raise the skirt assembly 42 by operating lefters 64 
to a level whereby the upper edges of plates 88 and 90 engage the end 
closure 78 to raise the fixed ring off its mounting. Thereafter, the fixed 
ring 70 can be transported with hood section 12a from the opening 30 by 
operation of the carriage 28. 
It will be understood that various changes in the details, materials and 
arrangements of parts which have been herein described and illustrated in 
order to explain the nature of the invention, may be made by those skilled 
in the art within the principle and scope of the invention as expressed in 
the appended claims.