CA1235878A

CA1235878A - Refractory fiber ladle preheater sealing rings

Info

Publication number: CA1235878A
Application number: CA000470867A
Authority: CA
Inventors: Mack A. Hounsel
Original assignee: THORPE (JT) Co
Current assignee: THORPE (JT) Co
Priority date: 1983-12-21
Filing date: 1984-12-21
Publication date: 1988-05-03
Also published as: DE3481592D1; WO1985002892A1; ATE50935T1; KR850700152A; IN163924B; AU3748185A; EP0150614B1; JPS61500777A; AU571301B2; US4492382A; EP0150614A2; EP0150614A3; ZA8410020B; BR8407233A

Abstract

ABSTRACT

REFRACTORY FIBER LADLE PREHEATER SEALING RINGS

Sealing rings are provided for ladle preheaters. The rings may be either fixedly or removably mounted with the ladle preheater frame. The rings seal about the ladle rim adjacent burner and flue openings of the preheater.
Refractory fiber insulation is provided for insulating the space between the rim of the ladle and the preheater to prevent hot gas escaping. The refractory fiber is arranged into trapezoidal units which are easily installed and replaced.

Description

~3~

TITLE: ~EFRACTO~Y FIBER LA~LE
PREHEATER SEALING RINGS
INVENTOR: Mack A~ Hounsel BACRGROUND OF INVENTION:
.
l. Field of Invention: The present invention relates to insulating and seali~g rings for ladle preheaters.

2. Descri~tion of Prior Art: U.S. Patents Nos.
4,229,211 and 4,364,729 related to ladle preheating systems which incorporate a refractory fiber lined wall or lid which mechanically seals against the rim of the ladle.
A burner and flue arrangement are centrally located on the wall or lid. The mechanical sealing function is critical to the efficient containment of th~ combusted yases. In these systems, substantially the entire rectangular support frame or plate was covered with refractory ceramic fiber modules, such as those accordiny tc U.S. Patent No.
4,001,g96. These modules, typically having square prismic shape, were installed in a unif~rm grid pattern. Since the ladle rim was usually o circular or oval construction, ~he modules in the outer corners of the frame served no useful function other than support for the modules which did lie within the seal area. Establishing a circular or oval seal area with a uniform square grid pattern involv~d the use of inactive modules. This increased the cost of construction and maintenance. The ladl~ rim was a g~nerally uneven surface and the modules during repeated sealing ac~ions were worn and displaced.
Joints between adjacent modules in the sealing area were ~3~

often forced apart because of this effect. This caused loss of sealing effectiveness and the possibility of damaging heat leakage.
U.S. Patent No. 4,223,873 disclosed a ladle preheater with a circular seal of ceramic fiber compaction material.
~owever, no structural details of this seal, or how it wa~
to be installed and supported, were given. The rectangular ceramic fiber modules used for furnace wall insulation, such as those of U.S. Patent No. 4,001,996 mentioned above, and others on the market, did not lend themselves to forming circular seals. There are several ways that attempts could be made to use them, but none was satisfactory. These square or rectangular modules could be cut to fit a circular or oval seal pat~ern.- This would cause material waste and increassd installation costs.
Even more importantly, however, the structural integrity and thus the compressive effects between adjacent modules would be reduced. Alternatively, these modules could be arranged about a yenerally circular pattern, leaving gaps in spaces between adjacent modules where curved surfaces were necessary. This would require stuffing to be inserted in the spaces, increasing installation costs and resulting in irregular compressive effects.
SUMMARY OF INVENTION:
Briefly, th2 present invention provides a new and improved apparatus or sealing th~ rim of a ladle as it is positioned adjacent a ladle preheater. A retainer member is formed on a front frame support of a preheater adjacent a burner inlet and an exhaust outlet of the preheater, enclosing the portions of the front frame support in the vicinity of the inlet and outlet. A plurality of refractory fiber ring insulation units ox modules are provided to engage and seal with the ladle rim, while also providing insulation in the space between the rim and the preheater. Each o the modules includes a plurality of adjacent layers of refractory ceramic fiber insulating material having an i~ner surface portion adjacent ~he ~5~3~8 preheater and an outer surface portion adapted to be contacted by the rim of the ladle during preheating. The refractory fiber insulation units are mounted by a mounting means which conforms to the shape of the rim of the ladle, whether oval or circular. The layers of the refractory ceramic fiber insulation unit are mounted on the mounting means in planes which extend radially outwardl~ from a central portion of the ladle so that the fiber insulation units are trapezoidal in shape, extending radially outwardly from an inner face to an outer face of greater extent than the inner face.
With trapeziodal insulation units according to the present invention, compression is attained between adjacent modules along lines of radial extent of the fiber layers. This diametrical compression is substantially uniform over the entire seal area rather than randomly criss-crossing the seal area. The sealing forces imposed by the ladle actually encourage the modules to seal more tightly together. In previous designs, the partial engagemen~ of some modules caused intramodular displacement and caused gaps to open up. The seal ring of the present invention in contrast behaves more as a compress monolithic mass of fiber ra~her than a collection of individual modules. The result of the present 25 invention i5 longer life and more positive sealing action.
The natural keying action of trapezoidal shapes also mak~s installation and maintenance much easier. The sealing apparatus of the present invention with trapezoidal insulating units also permits a new and improved insulating appara~us for ladle preheaters. Areas of the preheater adjacent the bu~ner can be lined with different types of insulation than that sealing the ladle rim. This affords longer insulation service life and reduces cost.
BRIEF DESCRIPTION OF THE D~AWINGS
_ Fig. 1 is an elevation ~iew of a removable ladle preheater seal ring according to the present invention;

_4_ ~358~8 Fig. 2 is a cross-sectional view taken along the lines 2-2 of Fig. 1;
Fig. 3 is an elevation view of a fixed ladle preheater seal ring according to the present invention;
Fig. 4 is a cross-sectional ~iew taken along th2 lines 4-4 of Fig. 3;
Fig. 5 is a plan view of a refractory fiber insulation module used in the seal rings of Fi~s. 1 through 4, inclusive;
Fig~ 6 is an elevation view of the refractory fiber insulation module of Fig. 5;
Fig. 7 is an isometric view, partially schematic, of an alternative attachment mechanism of the present in~ention for modules in a ladle preheater s~al ring.
DESCRIPTION OF PREFERRED EMBODIMENT
In the drawings, the letter A designates generally a sealing ring apparatus according to the present invention for sealing a rim R of a ladle L as the ladle L is positioned adjacent a ladle preheater. The ladle preheater may be a vertical or horizontal preheater, and may be any one of several types commercially available and structural details thereof, with the exception of a front or top frame support 10, are not shown. In the preferred embodiment, the front frame support 10 includes upper and lower support beams 12 and 14 and side beams to which a front metal plate 16 is attached. A burner opening 18 is formed in the plate 16 so that hot gases from the burner of the preheater may enter the interior of the ladle L in order to~preheat the ladle L~ An e~haust opening 20 is formed in the platP 16 so that continuous circulation of heated gases from the burner opening 18 into the ir.terior of the ladle L and out of the e~haust outlet 20 may occur.
A cylindrical inner section retainer member 22 is mounted extending outwardly from the frcnt frame support 16 of the preheater and encloses the portions of the front Xrame 16 ad~acent the ~urner inlet 18 and exhaust outlet 20 of the preheater. Portions of the front frame support ~2;~5~
--s--16 enclosed within the retainer member 22 are suitably insulatedO In the preferred embodiment, a plurality of modular refractory ceramic Eiber insulation modules 24 are mounted on the front frame support for insulation purposes. Th~ primary function of the modules 24 is to insulate the front frame 16 of the preheat~r from conditions within the ladle and to reduce neat loss.
These modules 24 may be of any of the types currently marketed, such a in United States Patent No. 4,001,936.
It should be understood, however, that other fiber modules, such as the types known in the art as "edge grain" or "nip and tuckl' may be used as well. Also, layered fiber construction, brick or other conventional hard refractories may be used in place of.ref~actory fiber modules. Openings are formed in the modules 24 adjacent the burner inlet 18 and exhaust outlet ~0 for the entry and exit of the gases into the interior of the ladle L.
A seal ring assembly frame member 26 is mounted on the frame support member 16 of the preheater and extends across the face of the support member 16 in a shape conforming to the rim R to be preheated. Thus, the seal ring assembly frame may be circular, elliptical ox oval in configuration in the plane in which contact is made with the rim R, based upon the configuration of the rim R.
25 Structural rails or beams 27 of the apparatus A are mounted with the seal ring assembly frame member 26 and extend towards the frame support 16 to stiffen the se~l ring assembly 26 and also to insure pxoper positioning of the seal ring A with respect to the frame support 16. It is to be noted that the structural beams 27 are not, however, permanently co~nected to the frame support 16 of the preheater, although they may be bolted thereto for stability of the appaxatus ~ in use. In this manner, in the event that the seal ring apparatus A needs replacement or repair, it may be removed as a complete assembly and another apparatus A easily installed with minim~m down or inoperable time for the preheater. Also, replacement or ~Z35~37~

repair of the apparatus A can be accomplished without disturbing the refractory modules 24 in the center sectio~
within retainer member 22. Different diameter removable seal ring apparatus A can also be provided for use with one preheater to accommodate dif~erent sizes of ladles.
It ~hould be pointed out that with the present invention, maintenance or complete replacement of the seal ring can be done without involving the independently lined center section. Previously, this area was relined each time the seal area modules were replaced, since trying to save certain modules during tearout was too tedious.
Whether the center section of the present invention is lined with fiber modules or conventional hard refractories, it may outlive numerous seal rings, saving considerable time and expense in maintenance and downtime.
On a typical ladle preheater, field operations indicate that the present invention can more than double the average life of the seal area while cutting the material cost for a relining job in half, since the center section is used over and over again. Downtime reductions are also significant.
An upper attachment tab 28 and a lower attachment tab 30 are formed as outward extensions of the mounting frame 26 so that an upper compression or retainer ring 32 and a lower compression or retainer ring 34 may be attached to the mounting frame 26 at upper and lower attachment tabs 36 and 38, respectively, by bolts or other suitable mounting means 40. The upper compression ring 32 has side mounting~tabs or luss 42 which are adapted to be connected by bolts 44 or other suitable attaching means to side attachment tabs 46 on the lower compression ring 34. The compression rings 32 and 34 support the insulation units I
in place against retainer member 22 and resist outward movement of these units when contacted by the rim ~.
Cradle arms 48 are mounted on support beams 50 to support the compression rings 32 and 34 ~bove the surface of the area adjacent the preheater. The cradle arms 48 support _7 ~2~35~7~

the load of the removable seal ring apparatus A when it is positioned with the preheater for sealing against the rim R.
A plurality of refractory fiber ring insulation units I of the seal ring apparatus A are moun'ced about the periphery of the seal ring assembly frame 26 extending radial~y wi~hin the space between the inner section retainer member 22 and the compression rings 32 and 34.
The insulation units I function to seal against the rim R
when contacted and to insulate the area of contact between the rim R and the preheater. A packing or gasket 52 is inserted about the retainer memher 22 after installation of the insulation units I to seal any annular space therebe~ween.
Considering the insulation units I more in detail, each takes the form of a plurality of adjacent layers of a suitable, commercially available, refractory ~eramic fiber insulating material, the particular fiber which is used beiny based on the expected temperature and service conditions. Each of the units I has an inner surface-portion 60 adapted to be positioned adjacent the mounting frame ~6 and an outer surface po~tion 62 adapted to be contacted by the rim R of the ladle L. Intermediate portions 64 of the adjacent layers of refractory ceramic fiber insulating material extend betwean th~ inner surface portion 60 and the outer portion 62. Previously, all the modules comprising the preheater lining were by necessity of the same thickness. The high wear seal area demanded a thicker module than was needed to insulate the inner area.
The present invention provides independent optimization of module ~hickness in the seal area for resistance to mechanical abuse a~d for cos~ effective insulation of the inner area inside retain~r member 22. Typically, the thickness of the units I between inner surface portion 60 and outer surface portion 62 is greater than that o the modules 24, in some cases as much as seven inches. In this manner, the units I are first to be contacted and ~3~i87~

d~maged by slag from the ladle L. Since the units I are easier to replace, an advantage is provided by using different thicknesses of sealing units I and insulating modules 24.
rl~hus, the rim sealing apparatus A with the trape20idal modules I and the modules 24 within the retainer memker 22 fonm a new and improved insulating apparatus for ladle preheaters with the advantages discussed above. In certain situations, the -trapezoidal modules I need not have radially oriented fiber lay~rs.
Rather, they may be trapeæoidal with layers extending between folds adjacent the retainer member 22 and folds adjacent the rings 32 and 34. Also, the ~ayers may extend diametrically from the center portion of the ladle L
between folds at the side faces of the trapezoidal module or between olds against the mounting frame 26 and olds adapted to be contacted by the rim R. Another alternative is to form a composite monolithic trapezoidal module from a number of layers of cut refxactory material.
In the embodiment shown in the drawings, folds 61 are formed at side portions from adjacent ones of the plurality of adjacent layers at each of the inner surface portion 60 and outer surface portion 62, forming an accordion-style ceramic fiber blanket. It should be understood, however, that in the insulating units I only the inner surface portions 60 or the outer surface portions 62 may have folds 64 formed, as in United states Patent No. 3,952,470. Also, the insulating units I may have the refractory fiber in the form of edge-grain layers, with no folds formed at either the inner surface portion 60 or the outer surface portion 62.
In the insulating unit I, refractory ceramic stuffing strips 68 are mounted between selected ones of the plurality of adjacent layers, causing the insulating unit I to form a trapezoidal shap~ (Fig. 5). With trapezoidal insulation units I of the present invention, several advantages are afforded. The layers of blanket in the ~:35~7~
_g_ units I are radially oriented in planes extending outwardly, between inner faces 65 and outer fac~s 67 of the unit I, from a central portion of the ladle. When the ladle rim R is circular, the center point of the rim ~
serves as the point of origin for the radial orientation of the layer of the blank~t. If the rim R is oval or elliptical, a point at or near the general ce~ter of each arcuate surface may serve as the point of origin, Where the rim is an elongate oval, rectangular modules, such as according to U.S. Patent 4,001,996 and other types on the market, may be used along ~he straight portions of the oval. This radial orientation of the fiber layers produces substantially uniform diametrical compression between adjacent units I about the fra~e member 26, without the presence of any connecting joints between them in the seal area. The trapezoidal shape of the units I
also permits them to be individually installed and removed without obstruction by adjacent units and with little, if any, effect on adjacent units.
The insulating units I receive a plurality of mounting support rods 70 which extend transversely through the plurality of transverse layers of the unit I in the intermediate portions 64 at a suitable distance from inner surface portion 60. The support rods 70 are of a length slightly less than the transverse dimension of the trapezoidal insulating unit I at the location in which ~hey are inserted. As can be seen in Fig. 5, each o the rods 70a, 70b and 70c is of a different length.
The rods 70 are receiv2d in openings formed in a C-shaped channel member 72, much in the manner, for example, of United States Patent No. 4,381,634. The channel member 72 is mounted with an attac~ment member 74 which attaches the s~pport channel 72 through the seal ring assembly frame 26 to the preheater. The attachment

3~ member 74 may be of any of the forms shown in United States Patents Nos. 3,952,470, 4,001,996 and 4,381,634 or o~her commercially available attachment ~tructure.

~23~87~

ln a preferred embodiment of ~he present invention, however, an alternative attachment mechanism (Fig. 7~ is utilized which provides for natural keying action by permitting radial sliding motion ~see the arrows in Fig.
3~ of the modules I during installation. This mechanism also insures that the insulating units I do not move radially outwardly after installation and that the insulating units I are firmly and properly moved into the appropriate position during installation. The attachment mechanism is particularly suitable for installation when the surface of frame sl1pport 16 is warped or uneven. In the embodiment of Fig. 7, like structure to that of Figs.
1 through 6 bears like refer~nce numerals. The rods 70 are received in a C-shaped bec~m or support channel 76 whose legs 78 extend inwardly from the inner surface portion 60 of the insulating unit I. The arms 78 of the beam channel 76 extend between adjacent layers of the insulating unit, much in the manner, for example, of United States Patent No. 4,381,634. It should be noted that the outer compression rings 32 and 34 hold all the modules I tightly against the inner section 22 but are not acted upon by the diametrical compression of the modules.
There are no radial forces on the rings due to fiber compression. The ring of modules is stable without inner or outer restraint. A slide channel member 80 is received wi~hin the beam channel member 76 inwardly of the rods 70.
The slide channel member 80 has limit lugs 82 formed at side portions thereof. The limit luys 82 on the slide channel 80 also prevent movement of the insulating units I
on the lower half of the frame support 26 away from the center portion of the preheating unit due to gravity during installation.
An i~ner stopping bracket 86 having a locking snap arm 88 formed therewith is fixedly attached, such as by welding studs in ope~ings 89, to the front of the support ring 26 at each location where an insulating unit I is to be installed. ~he limit stop 86 is adapted to engage an 7~3 inner end 80a of slide channel 80 and engage same when the insulating unit I has been properly positioned on the ~ace of the support ring 26. A pocket recess 90 is formed by removing a portion of the unit I adjacent an outer end 80b of slide channel 80 so that the outer end 80b is acce~sible to be welded or fastened to the support ring 26 once the unit I is in proper position against the center retainer ring member 22. The compression rings 32 and 34 are then attached. The beam channel member 76 slides along slide channel member 80 when the units I are contacted by compression rings 32 and 34. This insures that the rods 70 travel with the fibers in the units I to prevent fiber tearingO
In an alternative seal ring apparatus A-1 of the present invention, like structure to that of the apparatus A, bears like reference numerals. In the seal ring apparatus A-1, the insulating units I are fixedly mounted with the front face of the support member 16 of the preheater, as are an upper compression ring 134 and a lower compression ring 132 after the insulating units I
have been installed. Typically, the packing 52 is installed in apparatus A 1 before the units I and the compression rings 132 and 134. The units I are attached directly to the preheater frame support 16 rather than to a movable member. However, such attachment is otherwise made in a like manner to that of apparatus A. Thereafter, the compression rings 132 and 134 are used to urge the units I inwardly into position and compression rings 132 and 134 are then connected together by bolts 44, and also attached to the frame support 16, such as by welding. In this e~bodiment, repair or servicing of individual ones of the insulating units I requires that the preheater be taken out of service, rather than removal of the apparatus A and replacement by a new presealing unit while individual ones of ~he insulating units I are repaired.
- The foregoing disclosure and description of ~he invention are illustrative and explanatory thereof, and ~235~

various changes in the size, shape and mat~rials, as well as in the details of the illustrated construction may be made without departing from the spirit of th~ invention.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An apparatus for sealing the rim of a ladle as it is positioned adjacent a ladle preheater, comprising:
(a) a plurality of refractory fiber ring insulation units, each of said units comprising:
(1) a plurality of adjacent layers of refractory ceramic fiber insulating material;
(2) said layers having an inner surface portion adjacent the preheater;
(3) said layers further having an outer surface portion adapted to be contacted by the rim of the ladle during preheating of the ladle;
(4) said layers further having inter-mediate portions extending between said inner and outer surface portions;
(b) means conforming to the shape of the rim of the ladle for mounting said plurality of refractory fiber insulation units adjacent the preheater;
(c) said layers being mounted on said means for mounting in planes extending radially outwardly from a central portion of the ladle.

2. The apparatus of claim 1, wherein said insulation units have inner and outer faces transverse to their radial mounting planes and further including:
(a) an inner section retainer member mounted to the frame support of the preheater for enclosing the frame support adjacent a burner inlet and exhaust outlet for the preheater; and (b) compression ring means for supporting said insulation units in position when contacted by the ladle rim.

3. The apparatus of claim 2, further including:
a layer of refractory fiber insulation mounted between said inner faces of said units and said inner section retainer member.

4. The apparatus of claim 2, further including:
a seal ring assembly frame member adapted to be positioned adjacent the frame support of the preheater.

5. The apparatus of claim 4, further including:
means for removably attaching said compression ring means to said seal ring assembly frame.

6. The apparatus of claim 5, wherein said means for mounting comprises:
means for mounting said insulation units on said seal ring assembly frame.

7. The apparatus of claim 60 further including:
cradle means for supporting said seal ring assembly frame and said units adjacent the preheater.

8. The apparatus of claim 2, wherein:
said compression ring means is fixedly mounted to the frame support of the preheater.

9. The apparatus of claim 8, wherein said means for mounting comprises:
means for mounting said insulation units on the frame support of the preheater.

10. The apparatus of claim 2, further including:
a plurality of burner and exhaust refractory fiber insulation units mounted on said frame support within the interior of said retainer member.

11. The apparatus of claim 10, wherein:
said burner and exhaust refractory fiber insulation units are of different thickness than said ring refractory fiber insulation units.

12. The apparatus of claim 1, further including:
side portions formed from adjacent ones of said plurality of adjacent layers at said inner surface portions to form alternating inner folds.

13. The apparatus of claim 1, further including:
side portions formed from adjacent ones of said plurality of adjacent layers at said outer surface portions to form alternating outer folds.

14. The apparatus of claim 1, further including:
side portions formed from adjacent ones of said plurality of adjacent layers at said inner surface portions to form alternating inner folds; and side portions formed from adjacent ones of said plurality of adjacent layers at said outer surface portions to form alternating outer folds.

15. The apparatus of claim 1, further including:
refractory ceramic fiber stuffing strips mounted between selected ones of said plurality of adjacent layers to cause said units to be trapezoidal.

16. The apparatus of claim 1, wherein said means for mounting comprises:
(a) mounting rod means extending transversely through said plurality of transverse layers in said intermediate portions thereof; and (b) means for connecting said mounting support rod means to the preheater.

17. The apparatus of claim 16, wherein said means for connecting comprises:
(a) a support channel having openings therein for receiving said mounting support rod means wherein;
(b) means for attaching said support channel to the preheater.

18. The apparatus of claim 17, further including:
a slide channel member movably mounted with said support channel for relative movement to resist tearing of the fiber insulating material by said support rod means during installation.

19. The apparatus of claim 18, further including:
limit means for preventing movement of said units due to gravity during installation.

20. The apparatus of claim 18, further including:
stopping bracket means mounted for engaging an inner end of said slide channel member when said insulation units are in proper mounting position.

21. An apparatus insulating a ladle preheater as it is preheating ladles comprising:
(a) an inner section retainer member mounted to a frame support of the preheater for enclosing the frame support adjacent a burner inlet and an exhaust outlet for the preheater;
(b) a plurality of burner and exhaust refractory insulation units mounted on said frame support within the interior of said retainer member;
(c) a plurality of trapezoidal refractory fiber ring insulation units for sealing with the ladle rim and insulating the space between the ladle rim and the preheater; and (d) means conforming to the shape of the rim of the ladle for mounting said plurality of trapezoidal refractory fiber insulation units adjacent the preheater.

22. The apparatus of claim 21, further including:
compression ring means for supporting said insulation units in position when contacted by the ladle rim.

23. The apparatus of claim 21, wherein:
said burner and exhaust refractory insulation units are of lesser thickness than said ring refractory fiber insulation units.