US3068015A - Seal for rotating cylinders such as kilns and the like - Google Patents

Description

Dec. ll, 1962 A. J. ROUBAL 3,068,015

SEAL FOR ROTATING CYLINDERS SUCH AS KILNS AND THE LIKE Filed April 21, 1961 E 50 H33 ff-322 f4 45 i@ 3,068,015 SEAL FR RG'EATHNG CYLINDERS SUCH AS KILNS ANB THE LiKE Alexander I. Roubal, Milwaukee, Wis., assigner to Allis- Chalmers Manufacturing Company, Milwaukee, Wis. Filed Apr. 2l, 196i, Ser. No. M4554 5 Claims. (Cl. 277-8?) The present invention relates generally to sealing rings and more particularly to a novel seal for rotating cylinders, such as kilns and the like, which are used in combination with auxiliary equipment at the ends thereof whereby the ingress yand egress of substantial amounts of diluent and contaminating iluids therebetween are significantly reduced to a controllable and tolerable minimum.

In the description of the present invention, rotary kilns have been chosen to exemplify rotary cylinders of the type herein contemplated although the present invention is not intended to be so limited.

Essentially, the problem encountered and solved bythe present invention arises, for example, in connection with the' processing of material in a rotating kiln having a material feeder at one end of the kiln and a firing hood and burner at the other end. It is the normal practice to attach such apparatus as a firing hood relative to the kiln in telescopic fashion, i.e., the hood will surround and overlap the end of the cylinder. Such telescopic arrangements must be loose, that is, an annular opening must be provided between the surrounding equipment and the surrounded equipment to permit, particularly at the burner end, and maintain the continual free rotational movement of the kiln in spite of the thermal distortion normally attendant such a setup. Further, the annular opening is essential because the equipment settles on its foundation which, even though slight, is sufficient to further bind the pieces if the opening were not provided.

With such an annulus present, however, processing problems arise. Thus an ingress of air from the surrounding atmosphere through the annulus dilutes the burner gases and greatly impairs the fuel economies so essential to mineral processing. Further, an egress of exhaust gases (irrespective of whether countercurrent or parallel gas flow is employed) spreads dust and, depending on the material treated, foul odors to the nearby community. Certain materials treated in this manner are also found to be highly corrosive upon dispersion into the normally moist air characteristic of a major portion of the North American industrial area.

A further problem arising from an unattended annulus is in the control of the draft. Thus, whe-re a burner is used to create a reducing atmosphere in a kiln by ooding with fuel and controlling the oxident (as in the production of sponge iron and the like from its oxide salts), it is essential that the additional oxygen from the air be precluded from the kiln to avoid upsetting the desired fuel-oxygen ratio and which could radically change the operating conditions in the kiln. Y

According to the teachings of the prior art, a relatively rigid annular sealing ring is usually provided to enclose such an annular opening and overcome the aforementioned problems.

The ring is frequently L shaped in cross section. That is, the ring comprises an axially extending collar portion engaging an outer circumference of the kiln, and a radially extending flange portion engaging kiln-surrounding structure of a hood assembly. However, since the kiln is frequently of very large diameter, it is quite diicult to make it perfectly round. Furthermore, once in operation the very high temperatures within the kiln may cause warping that results in the kiln being even more out of round. The relatively rigid sealing rings of the prior art do not easily or completely conform to the shape of an Stats twee Patented Bec. ll., i932 out-of-round kiln and result in the collar portion of the ring engaging the kiln too tightly at spaced locations around the shell while at the same time leaving openings that tend to reduce or defeat the eectiveness of the sealing ring to do the job heretofore described.

According to the present invention a sealing ring, L shaped in cross section, is provided that is made up of segments. The segments are arranged to form a complete ring around the kiln. The segments are held in engagement -with each other and the outer shell of the kiln by one or more cables wound around and secured to the axially extending (and kiln engaging) collar portion of the segments. The segments may initially be bolted together during the assembly thereof but once the cables are arranged and secured any such bolts are removed so the ring of segments can easily conform to an out-ofround shape of the kiln. Adjacent segments engage each other by overlapping joints so that, for example, when a kiln thermally expands to a larger diameter, the cables will be stretched but no spaces for leakage will open between adjacent segments.

Accordingly, one of the primary objects of the present invention is to vprovide a suitable kiln air seal which conforms easily to engage a warped out-of-round kiln, to maintain it in sealing engagement over the annulus intermediate the auxiliary equipment and the kiln.

Another object of the present invention is to provide an improved sealing ring which can be easily stretched to accommodate thermal expansion of the circumference of the kiln and maintain sealing engagement over an annular opening circumscribing the kiln.

Another object of the present invention is to provide an improved sealing ring of segmented construction that provides for relative movement between segments without opening passages therebetween, through which leakage can occur.

These and still further objects are fulfilled by the present invention in a manner that will appear from the following detailed description when read in conjunction with the accompanying drawing.

ln the drawing, FIG. l is a fragmentary side elevation in section, showing a rotary kiln embodying the present invention;

FIG. 2 is a fragmentary view taken along line `ll-Il. of FIG. l with details of the kiln being omitted for clarity;

FIG. 3 is a fragmentary view in section taken along line Ill-lll of FIG. 2; and

FIG. 4 is an enlarged fragmentary View of a portion of the structure shown in FIG. 2 taken along line IV-IV of FIG. 2.

ln FIG. l, a conventional rotary kiln 11 inclines slightly downwardly toward a burner hood 13 to assist in the translation of material therethrough. Kiln l1 comprises a tubular shell 14 having an internal lining 15 formed of a suitable refractory material such, for example, as refractory bricks. Suitable drive means (not shown.) are provided for rotating the kiln.

An annular end plate 16 is secured at the end of shell 14 and defines a substantially circular opening 1'7 (hereafter called discharge opening) through which the material, after treatment in the kiln is discharged to conveyors, coolers and the like according to the exigeneies of the material being treated.

A cooling jacket 2t) may be provided in circumscribing relationship to shell 14. Such a jacket is found particularly desirable when the material being processed requires high temperatures. When exceedingly high temperatures are used, the discharge end encounters severe thermal conditions. The use of a cooling jacket, therefore, helps to dissipate some of the heat from the end of the shell to overcome to a, certain extent the serious disspasms E torton otherwise resulting from the action of the heat on the metal shell.

Adjacent the discharge end of kiln 11, burner hood 13 comprises a housing 22 having a lining 23 formed of a suitable refractory material. Hood 13 contains a conventional burner 24 through Whichis fed the mixture of fuel and oxygen desired for the specific process to be employed in the kiln.

Hood housing 22 includes a front Wall 27 having dened therein an annular opening 2S which circumscribes the cooling jacket 2t) to define an annulus 29 therebetween. Where the particular kiln application does not require a cooling jacket 2t?, annular opening 28 is adjusted in dimension to define annulus 29 with the shell 14. A bearing ring 39 may be attached to a portion of hood front wall 27, and extend radially inward from opening 28.

An annular sealing ring 33 shown in FiG. 2 is arranged (see FIG. l) in circumscribing relationship to shell 1.4 for closing annulus 29 to the passage of gases therethrough.

Ring 33 as shown in FIG. 2 is made up of a plurality of segments 35. The segments 35, see FIGS. 2, 3 and 4, each have a cylindrical collar forming portion 36 and an annular flange forming portion 37 projecting radially outward from the collar portions 36. The segments 35 are tied in a ring around the kiln 11, for example as shown in FIG. l, with the collar forming portions 36 engaging the outer circumference of cooling jacket 20 and the ange forming portions 37 engaging bearing ring 30. The individual segments 35 are tied together, to form the ring 33, in a manner that can best be described with reference to FiGS, 3 and 4.

As shown in FIGS. 3 and 4, a pair of bolts 40 project radially outward through each collar portion 36. The bolts 4t) have a head 41 that is tted in a recess 42 in an inner circumference 38 of collar portion 36 so that the inner circumference 3S is a smooth surface for engaging kiln 11 in the manner previously described. A jaw 45 having a hole 46 is placed over each of the bolts 40. The bolts 40 project through and `radially outward` of each jaw 45. The bolts 40 are each threaded to engage a nut 47 which when turned to advance along bolt 40 toward the head 41, moves the jaw 45 radially inward toward the collar forming portion 36. A pair of cables 50, 51 are arranged between jaw 45 and collar portion 36. The cables 50, 51 are parallel to the ange forming portions 37. One of the cables, i.e. 51, is on the side of bolts 40 closest to ange 37 and the other cable, i.e. 50, is on the side of bolts 40 remote from ange 37. The radially inward surface of jaws 45 and at least the areas of collar portions 36 facing jaws 45, are shaped to dene encircling passages 52, 53 for gripping the cables 50, 51.

When assembling the ring 33 around the kiln 11, bolts (not shown) may be temporarily inserted in the holes 60 in the lugs I, see FIGS. 2, 3 and 4, to form a ring. After the cables are strung and secured by the clamping and gripping action of jaws 45, such bolts may then be removed.

After temporary bolts have been removed, the ring 33 may flex to conform to shape of the engaging surfaces. An overlapping contact between adjacent segments is provided as shown at 63 in FIG. 4. Thus adjacent segments can move relatively to each other without opening passages for leakage into or out of kiln 11 and hood 13.

With the arrangement described wherein a pair of jaws 45 are mounted on each segment 35, it is not necessary that the cables 50, 51 each be continuous strands as shown in FIG. 2. The segments can be joined by short lengths of cable, as short as the portions of cables 50, 51 that are shown in FIG. 4. Cables that are continuous, or

nearly so, are to be preferred, however, because then an unintentional loosening of one or even several of the jaw assemblies will not cause Vthe ring to come apart as might happen if short strands of cable are used.

From the foregoing it can be appreciated that the present invention provides a seal for kilns and the like that will be durable, relatively inexpensive, can be readily assembled and disassembled when necessary. Furthermore, the present invention provides a seal that will conform to a warped or otherwise out-of-round kiln, stretch to accommodate thermal expansion of the kiln, and all without opening passages through which leakage can occur.

Thus it can be seen that the described construction accomplishes the objects of the inventions previously referred to as well as others. However, modifications and equivalents such as readily occur to those skilled in the art are intended to be included within the scope of this invention and thus the invention is intended to be limited only by the scope of the appended claims.

Having now particularly described and ascertained the nature of my said invention and the manner in which it is to be performed, I declare that what I claim is:

1. A segment adapted to coact and form with similar segments an annular sealing ring presenting a cylindrical collar adapted to engage and be tied around an outer surface of a cylidrical kiln by a circumferentially arranged cable and an annular ange projecting radially outward of the cylindrical collar, comprising, an adjoining cylinder forming portion and radially outward flange forming portion, a jaw arranged radially outward of the cylinder forming portion, the jaw and the cylinder forming portions being adapted to grasp therebetween a cable arranged parallel to the flange forming portion, and clamping means engaging both the jaw and the cylinder forming portion operative to move the jaw radially inward toward the cylinder forming portion.

2. A segment according to claim l in which the radially inner surface of the jaw and the radially outer surface of the cylinder forming portion dene therebetween a cable encircling passage parallel to the flange forming portion.

3. A segment according to claim 1 in which the clamping means comprise a bolt projecting radially outward through a cylinder forming portion and the jaw, and a nut engaging the bolt radially outward of the jaw and operative to advance along the bolt in a radially inward direction to move the jaw toward ythe cylinder forming portion.

4. A segment according to claim 3 in which the radially inner surfaces of the jaw and the radially outer surface of the cylinder forming member define therebetween a pair of cable encircling passages, with both of the passages being parallel to the flange forming portions, and with the bolt projecting outwardly between the passages.

5. Apparatus comprising a stationary structure and a rotating cylindrical shell telescopically arranged therein, theshell coacting with the stationary structure to define an annular opening therebetween disposed in circumscribing relation to the shell, and a sealing ring circumscribing the shell adjacent the stationary structure and closing the annular opening, the sealing ring comprising a plurality of adjacent segments each having a cylindrical collar forming portion engaging the shell and a radially outward flange forming portion engaging the stationary structure, and a cable tied around the outer circumference of each of the cylinder forming portions of the segments to hold the segments in conforming engagement with the shell.

No references cited.

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