US2613826A

US2613826A - Rotary seal for furnace tops

Info

Publication number: US2613826A
Application number: US122185A
Authority: US
Inventors: Dawbarn Waring Lennox
Original assignee: Arthur D Little Inc
Current assignee: Arthur D Little Inc
Priority date: 1949-10-19
Filing date: 1949-10-19
Publication date: 1952-10-14
Anticipated expiration: 1969-10-14

Description

Oct. 14, 1952 Filed Oct. 19, 1949 w. DAW BARN ROTARY SEAL FOR FURNACE TOPS 2 SHEETS SHEET l INVENTOR.

O'LM 4 64:

Oct. 14, 1952 w, DAWBARN 2,613,826

ROTARY SEAL FOR FURNACE TOPS Filed Oct. 19, 1949 2 SHEETS-SHEE'I 2 76 4 7O\\@ 5 54- ea FIG. 3

3a. 28 L [7 q INVEN TOR. WAR/N6 Lew/vex DIM/642M Patented Oct. 14, 1952 ROTARY SEAL FOR FURNACETOPS Waring Lennox Dawbarn, Winchester, Mass., assignor to Arthur D. Little, Inc., Cambridge, Mass, a corporation of Massachusetts Application October 19, 1949, Serial No. 122,135

This' invention relates. to sealing means for preventing the flow of gases between parts which are moving with respect to" each other. More particularly it relates to sealing means forrevolving distributors located at the tops of blast furnaces. I

Blast furnaces are'customarily provided with an' upper hopper which rotates and which projects, at its lower end," downwardly into the chamber between the upper and lower bells. Since the chamber walls do not rotate, an annular space must be provided between the outside wall of the hopper and the upper end of the chamber walls through whi'ch'the hopper projects, to permit rotation of the hopper. During operation of the furnace, there is, during at least a part of the charging cycle, a pressure differentialbetween the chamber and the outside atmosphere, so that furnace gases, generally dustladen, pour out through the annular space between the hopper and the chamber walls, in

the absence of sealing means in said space. Aside from the undesirability of discharging gases and dust to the atmosphere, there is the serious hazard to personnel working at the top of the furnace. This hazard, especially from the furnace gases, largely due toCO content, has led to the safety requirement that no personnel shall go singly to the furnace top; yet even when two or three men are present there together, serious poisoning effects from the gas are not infrequent. Furthermore, the dust associated with the escaping gases is strongly abrasive, and has a severe wearing effect as it escapes.

These drawbacks are serious enough when the furnace is operated under normal conditions; they are of course increased when the furnace" is operated under high top pressure.

Although various sealing means have been used in efforts to overcome these difiicultiesthey-have not proved satisfactory in actual practice, especially when operating under high top pressure.

They are eitherimpractical to installfor they are ineffective because of the nature of the gases being restrained, i. e. their pressure, temperature, composition, and abrasive-dust content, or because of theslight vertical and lateral irregulari} ties "in the movements of"the"'small bell hopper. An increase in pressure within the" bellchamber tends to raise the small bell hopper slightly, while the rotation of the small bell hopper,fir 'st in one direction and then in the other, causes a slight lateral shift in the position'of the hopper. Seals 4 hitherto used have beentoo' rigidly fixed in their positions to accommodate these I verti'caljand' lateral'irregularities without leakage of gas.

:bell I2. 'All' of Jtheforegoing,parts an I.

V 7"Claims. (Cl. 214-36) 2 The present invention provides a relatively simple means for overcoming these drawbacks and for providing a gas-tight seal between relatively-moving parts, which seal is effe 'ctive to prevent the passage of abrasive-laden gases, under pressure, between said relatively-moving parts. And while it'is of 'par'ti'cula'rvalue for'use in blast furnace tops, as aforesaid, it is likewise of value in providing a gas-tight seallbetwee'i'i two, bodies so placed with respect to each other that i there is an annularspace. between' them, said bodies being rotatable with respect to each other, about an axis'which is'thefaxis of said annular space the s'eal being for the purpose of preventing passageof'g'as through said space will now be described in detail with reference to its use in a blast furnace'top, in connection with the accompanying drawings, wherein:

Fig. 1 is a schematic view of the top portion'of a typical blast furnace employing the'j fs'ealing means of thisinvention; 1

Fig. 2 is "a verticalsectional elevation through the. rotating hopper and 'seal of such' a blast furnace;

Fig. 3 is'an enlarged'view, in cross section, of'a portion of Fig.1 showing "in" greater detail the features of the se'al; and

Fig. 4 is a-sectional 'plan view taken along the line 4-4 of Figc3." j' In Figi'l there is shown a portion of the top of a typical blast furnace; in which-the sealing means of the present invention is employed This furnacetop-includes the conventional rotat-j' ing small bell hopper ill; small bell l'2,"largeb el'l hopper l iflarge bell, i 6, 'bell" chamber 118 between said small belland saidflargefbell and top'wallf of the blast furnace shaft is indicated 'by nurner'al 26; Small bell hopper i 0 is rotated intermittently by means showngenerally by referencenuineral 28, so that the charges dumped into saidfhdpp'er will bedistr'ibuted sufficiently evenly upon'small operationajre convent tice and construction As shown in' more deta projects downwardly" a1 blast of hopper myths; is" substantially. aririu a shape, withfaniaxi's common to, that.. ofedge 4f";

" and hopper l0.

. ment.

Hopper It! is supported in conventional manner, e. g. by rollers 36 which support ring member 38 attached to flange 40projecting from hopper I; guide rollers 42 are also provided. These guide rollers 42 restrict upward movement of the hopper I!) caused e. g. by increase in pressure in bell chamber [8, although as already pointed out they do not entirely prevent such upward move- I-Iopper m is rotated in conventional manner, e. g. by motor or other power means 28 which meshes with teeth 44 provided around the periphery of ring member 38. As the hopper is thus-rotated, first in one direction and then in the opposite direction, there is a slight lateral movement of the hopper, as already stated. It

is impractical, if not impossible, to construct a furnace top in such a manner as to avoid these vertical and lateral movements.

When the small bell i2 is in closed position and large bell I6 is open or not tightly seated, there will be superatmospheric pressure in bell chamber l8'in an amount depending upon the pressure Within the top of blast furnace shaft .26. These ases, 'ladenwith more or less dust of abrasive nature will, unless prevented, pour out through opening 32, wearing away the edge 34 and the adjacent side of hopper Ill and contaminating the air, especially around the furnace top, with gases poisonous to personnel.

The seal of the 'presentinvention is mounted with relation to edge 34 and hopper I0 and effectively prevents the passage of air or other gases through space '32 in either direction, regardless ofthe slight vertical and lateral movements of hopper I 0, and of variations in pressure in chamber 18 including sudden surges due to slips and rolls 'in the furnace. The seal comprises several parts, as shown generally in 'Fig. 2 and in more detail in Figs. 3 and 4. These parts will now be described;

Attached to the periphery of hopper H], e. g.

. to adjacentilange 40, is a supporting ring 46, to

which inturn is attached by bolts 41 flexible member 48 of cylindrical shape, said .flexible member being spaced radially from said hopper. Ring 46 may conveniently be in say six sections, for convenience in attaching to existingfurnaces, and its attachment to hopper. [0 is in gas-tight v relation; Flexible member 48 is also attached in gas-tight relation to ring 46;';this relationis assured by providing metal ring 50 which surrounds flexible member 48 and is held tightlyin position-by bolts'41. Another cylindrical member '52, non-yielding and preferably of metal, is provided to fit around flexible member. 48' so that the latter slides against it as hopper Hlis rotated. This member 52, which mayalso be made in say six sections for convenience in installing, is mounted in gas-tight relation with edge 34 of top 20.,e. .g. by bolts v54 extending through ring 56 to spider 58, which is attached tothe top of edge 34 by bolts 59. Conventional packing 60 may remain in place, if desired, but it is not necessary.

Cylindrical member 52 is provided with an inner lip 62, which holds an annular buffer member 64 which is kept in position by annular retaining ring 66 fastened to lip 62 by bolts 68. Bufier member 64 is preferably of flexible material and may be in the form of a ringor a hollowitube. It bears against the loweriend of flexible'member 48, in sliding relation, and serves to maintain said'member 48 in contact with member 52. By this means, flexible member 48 is prevented from pulling away from member 152 pcant, which may advantageously be of oil and colloidal graphite, works up and down from its distribution points over all of contacting surface 74 between

cylindrical members

48 and 52, to facilitate the sliding of said members with respect to each other Distributing wells or reservoirs 75 may be provided, if desired, in the inner face of, member 52 at points where the oil lines emerge, to assist in providing a body of lubricant against the outer face of member, 48 and assist in spreadin the lubricant over the contacting surfaces.

Member 48 is made flexible in order to accommodate the already-mentioned slight vertical and lateral irregularities in the movement of hopper ID as it revolves. Any good rubber or synthetic rubber compo'sitionhaving toughness and dimensional stability and areasonable degree of heat stability'is satisfactory for fabrication of member 48, as well as of buffer member 64.

It is clear from the foregoing that cylindrical

members

48 and 52;and buffer-member 64, as well as hopper l0, space 32, and edge 34, all havea common axis, which is located essentially at the center line of the bell rods. Such concentricity is of course necessary for the proper close sliding fit at surface l4 during rotation of hopper l0. 7

During operation of the blast furnace, the cylindrical member 52 of the sealof this invention remains in fixed position, being so held by thesupporting means hereinabove described with .respect'to'top edge 34 and in gas-tight'relation therewith. v Annular buffer member 64, being attached to member '52, likewise remains in fixed position. Flexible member 48, however, rotates as hopper 'llljrotates, andduring thisrotati'on' it is *normally held in "gas-tight relation against member 52 along surface 14 by gas pressure within chamber 18, which pressure bears against the inner cylindrical'surface TS-of member*43. In the'event that'suc'h gas pressure falls to ambient pressureor below, annular buffer member 64 holdsmember :48 against member52 While "the "seal o: this invention has been described "in detail f in connection with its use in blast furnace .tops, it may of course be used in 7 Various such uses within the scope of the ap-' pended claims will "suggest themselves to those skilledinthe artf" "Iclaim: j 1. In a blast furn hopper, a lower'bell and having an upper bell and hopper, a ch'amberfthere- .betweenfand means lforrotating said upper hopper, saidupper hopper "extending downwardly mounted concentrically, and in fixed relation,

with respect to said retaining member, and in sliding relation with respect to said, flexible cylindrical member, and adapted to urge said flexible cylindrical member toward said retaining member, said latter two members being positioned substantially concentrically with respect to said upper hopper.

2. In a blast furnace having an upper bell and hopper, a lower bell and hopper, a chamber therebetween, and means for rotating said upper hopper, said upper hopper extendingdownwardly into said chamber through an opening in the top of said chamber: sealing means to prevent flow of gases between said chamber and the atmosphere through said opening, said sealing means comprising a flexible cylindrical member positioned in gas-tight relation to said upper hopper and spaced radially therefrom, a cylindrical retaining member against which said flexible cylindrical member slides when said upper hopper is rotated, said retaining member being associated in gas-tight relation with the walls of said chamber and adjacent said opening in the top thereof, an annular buffer member mounted concentrically, and in fixed relation, with respect to said retaining member, and in sliding relation with respect to said flexible cylindrical member, and adapted to urge said flexible cylindrical member toward said retaining member; and means for introducing a lubricant between the contacting faces of said flexible cylindrical member and said retaining member, said latter two members being positioned substantially concentrically with respect to said upper hopper.

3. In a blast furnace having an upper bell and hopper, a lower bell and hopper, a chamber therebetween, and means for rotating said upper hopper, the lower end of said upper hopper extending downwardly into said chamber through'a circular opening in the top wallsof said chamber, thereby defining an annular space between said upper hopper and the edges of said opening; sealing means to prevent flow of gases between said chamber and the atmosphere through said space, said sealing means comprising a flexible cylindrical member attached in gas-tight relation to supporting means, and spaced radially from said upper hopper, said supporting means being attached in gas-tight relation to said upper hopper, a non-yielding cylindrical retaining member against which said flexible cylindrical member slides when said upper hopper is rotated, said retaining member being associated in gas-tight relation with the walls of said chamber and adjacent said opening in the top thereof, and means for introducing a lubricant between the contacting faces of said flexible cylindrical member and said retaining member, said latter two members being positioned substantially concentrically with respect to said upper hopper, said flexible cylindrical member and said retaining member being sov positioned that the major portion of the outer surface of theformer. member is juxtaposed with the major portion of theiinner surface of the latter, member, said flexible cylindrical member being adapted to be urged, ,by the pressure of gas from said chamber against the inner surface of said flexible cylindrical member, against said retainingmember. so as toeffect detailed conformationwith the said juxtaposed surface of said retaining member and thereby form a tight seal against ,escape .of said gas between said juxta posed. surfaces.

4.;In a blastlfurnacehaving an upper bell and hopper, a lower, bell and hopper, a walled chamber therebetween, and means for rotating said upper hopper, the lower end of said upper hopper extending downwardly into said chamber through a circular openingin the top walls of said chamber, therebydefiningan annular space between said upper hopper and. the edges of said opening; sealing means to prevent flow of gases between said chamber and the atmosphere through said space, said sealing means comprising aflexible cylindrical member attached in gas-tight relationto supporting means, and spaced radially from u said upper hopper, said supporting means being attached in gastight relation to said upper hopper, said flexible cylindrical member and said supporting means being. arranged to rotate With said hopper,a-non-'yielding cylindrical retaining member. against which said flexiblecylindrical member'slides when said upper hopper is rotated, said. retaining member being associated in gastightrelation with the walls of said chamber and adjacentsaid opening in the top thereof, an an-' nular buffer member mounted concentrically, and

, infixed relation, with respect to said retaining member, and insliding relation withrespect to said flexible cylindrical member, and adapted to urge said flexible cylindrical member toward said retaining member, and means for introducing a lubricant between the contacting faces of said flexible cylindrical member and said retaining member, said latter two members being positioned substantially concentrically with respect to said upper hopper.

5. In a blast furnace having an upper bell and hopper, a lower bell and hopper, a chamber there- .between, and means for rotating said upper hopper, said upper hopper extending downwardly into said chamber through an opening in the top of said chamber: sealing means to prevent flow of gases between said chamber and the atmosphere through said opening, said sealing means comprising a flexible cylindrical member supported adjacent its upper edge in gas-tight relation to said upper hopper and spaced radially therefrom, a cylindrical retaining member against which said flexible cylindrical member slid es when said upper hopper is rotated, said retaining mezm ber being associated in gas-tight relation wilh 6. In a device having two contiguous bodies with an annular opening between said bodies. one of said bodies-being rotatable with respect to the other; sealing means to prevent flow of gases between said bodies through said opening, said sealing means comprising a flexible cylindrical member positioned in gas-tight relation to the inner one of said bodies and spaced 'radially therefrom, a cylindrical retaining member against which said flexible cylindrical member slides when said inner body is rotated, said retaining member being associated in gas-tight relation with the walls of the outer one of said bodies, an annular buffer member mounted concentrically, and in fixed relation, with respect to said retaining member, and in sliding relation with respect to said flexible cylindrical member, and adapted to urge said flexible member toward said retaining member, and means for introducing a lubricant between the contacting faces of said flexible cylindrical member and said retaining member, said latter two members being positioned substantially concentrically with respect to the axis of said inner body.

y 7. In a device having two contiguous bodies with an annular opening between said bodies, one of said. bodies being rotatable with respect to the other sealing means to prevent flow of gases between said bodies through said opening from a zone of higher pressure on one side of said opening to a zone of lower pressure on the other side, said sealing means comprising a flexible cylindrical member positioned in gas-tight relation to the inner one of said bodies and spaced radially therefrom, a cylindrical retaining member against which said flexible cylindrical member slides when saidinner body is rotated, said retaining member being associated in gas-tight relation with the walls of the outer one of said bodies, and means for introducing a lubricant between the contacting faces of said flexible cylindrical member and said retaining member, said latter two members being positioned substantially concentrically with respect to the axis of said inner body, said flexible cylindrical member'and said retaining member being so positioned that the major portion of the outer surface of the former member is juxtaposed with the major portion of the inner surface of the latter'm'ember, said flexible cylindrical member being adapted to be urged, by the pressure of gas from said zone of higher pressure against the inner surface of said flexible cylindrical member, against said retaining member so as to effect detailed conformation with the said juxtaposed surface of said retaining member and thereby form a tight seal against escape of said gas-between said juxtaposed surfaces.

VVARING LENNOXI DAl/VBA R N.

REFERENCES orrun The following references are of record in the file'of this patent: f

UNITED STATES PATENTS r Great Britain June 25, 1943