"Multi-Segment Seal Ring for Rotary Eguipment" Background and Summary of the Invention The invention relates to sealing structure for rotary eguipment of the type in which a relative large-diameter cylindrical shell is supported with its axis horizontal by inlet and discharge housings, arrangements of this charac¬ ter being commonly employed in the treatment—e.g., heat¬ ing, cooling, drying, etc.—of granular and like material, as by heating, cooling, etc. tubing extending through the shell. Because the size of the shell militates against the manufacture and maintenance thereof as a perfect cylinder, special sealing problems exist between the shell and its fixed related housings, the out-of-round condition of the shell magnifying the possibility of material leakage at the junctions of the shell and housings. These problems have been met, in large part, by the provision of one form or another of segmented seal ring at the areas in guestion, whereby the sealing ring can accommodate and follow the out-of-round condition of the shell. Copending U. S. patent application Serial No. 618,984, filed June 8, 1984, now

U. S. Pat. No. 4,502,702, contains as its subject matter a form of segmented seal ring upon which the present inven¬ tion comprises one or more improvements.

In the structure referred to above, each pair of neighboring segments is provided with overlapping end por¬ tions that cooperate to form a gap and radial interface at the junction of the segments. As the cylindrical shell rotates, its slightly "ovalized" shape is accommodated by the segments as they move circumferentially and radially in response to "high spots" on the shell. Thus, the

- 2 - circumferential dimension at each gap constantly changes. The presence of the gaps invites the entrance of material into the gaps, each of which is normally formed by spaced apart parallel edges of the neighboring end portions of the segments. Material, especially of soft, relatively moist nature, tends to pack solidly in the gaps and ul¬ timately creates a situation in which the seal ring not only increases in diameter but loses its flexibility and thus its sealing effectiveness is diminished if not destroyed.

According to the present invention, packing of mate¬ rial in the gaps is prevented or at least materially mini¬ mized by providing each gap with a relatively wide mouth at the arcuate inner edges of the segment end portions where these arcuate edges ride the shell, together with a sealing element blocking the gap at the junction of the mouth and the adjoining narrow part of the gap. Hence, the material has more room to work its way out of the mouth, especially since the mouth is shaped with radially outwardly converging walls. The location of the flexible sealing element at th% point noted prevents the material from entering and packing into that portion of the gap radially Beyond the mouth, that portion being conveniently formed by closely circumferentially spaced apart parallel radial edges. Further features and advantages of the in¬ vention will become apparent to those versed in the art as preferred embodiments are disclosed in detail in the ensuing description and accompanying sheets of drawings. Description of the Drawings Fig. 1 is a side elevation of a typical rotary appa¬ ratus of the type in which the invention finds particular utility.

Fig. 2 is an enlarged end elevation as seen along the line 2-2 of Fig. 1 Fig. 3_ is a further enlarged portion of the structure

shown in Fig. 2.

Fig. 4 is a section on the line 4-4 of Fig. 3. Fig. 5 is an "exploded" perspective of neighboring sections and especially illustrating the cooperating,over¬ lapping end portions. Fig. 6 is a similar perspective but drawn to show the side opposite that of Fig. 5.

I Fig. 7 is a perspective similar to Fig. 5 but showing a modified form of the invention..

Fig. 8 is a view similar to Fig. 3 but showing a od- ified form of cable wrap as applied to the segments. Description of Preferred Embodiments of the Invention An overview of the basic environmental structure in¬ volved in the rotary equipment of the character previous- ly referred to herein will be obtained from Fig. 1, wherein the numeral (10) designates a relatively large cylindrical shell associated at one end with an inlet housing (12) and associated at its other end with a dis¬ charge housing (14). The cylinderor shell is shown as > being driven by an electric motor (16) having a pinion (18) in mesh with a ring gear (.20) affixed to and en¬ circling the shell. Support for the rotary shell is fur¬ nished by a pair of sets of rollers (22) on which ride shell-encircling bands or tires (24) . As pointed out in the copending application, the shell may have a diameter upwards of four feet or more and is formed of sheet steel or the like. In basic operation, material to be treated within the shell is introduced at the inlet end (12) and progresses lengthwise or axially of the shell to exit at the discharge end (14) .

As best shown in Figs. 2, 3 and 4, the housing (14) (which may be taken as typical also of the inlet housing (12)) is formed with end walls (26) that are spaced axially and disposed radially as respects the axis of rotation of the shell (10) . An annular band (28)

surrounds and is fixed to these walls to provide a chamber (30) into which the associated end portion of the shell extends and this portion of the shell has therein a plurality of outlets or openings (32) . It is in this area that the sealing problem exists as the material exits through these openings into the chamber for ulti¬ mate discharge and, unless, sealed, would tend to escape past the walls (26) prior to final discharge.

As respects the discharge area, there are two seg- raented seal rings, each designated in its entirety by the numeral (34) . Because these are similar—in fact, mirror images of each other—only one will be described. Like¬ wise, similar seals are provided at the inlet end, not shown with the same degree of particularity as those at the discharge housing (14) . The seal ring encircles the shell and comprises a plurality of arcuate segments (36) , disposed substantially end-to-end except that each pair of neighboring segments has mating end portions (38) con¬ figured to overlap at a radial and circumferential inter- face (40) . Each segment has a radius on the order of that of the shell (10) and the circumferential length of each segment is such that, in addition to the plurality of the interfaces (40) , there also exists a plurality of associated gaps (42) . The segments are tensioned about the shell in such fashion as to hug the shell during operation, the tensioning means in this case comprising a cable (44) that engages and has a circumferential wrap about the segments. The cable has opposite ends adjust¬ ably connected by tension springs (46) to anchor points (48) affixed to the associated housing wall (26) . Each wall is supplemented by having welded or otherwise rigid¬ ly attached thereto an annulus or continuous ring (50) to

_*• which the segmented ring is attached in such manner that the latter may have "floating" movement to accommodate high spots on the rotating shell (10) . The form of

- 5 - attachment shown here comprises a plurality of slot and stud connections (52) (Figs..2 and.6) which allows limited but adequate radial movement of the individual segments, a characteristic which is not inhibited by the gap and interface relationship between the segment end portions (38) . The cable wrap is accommodated by the provision of circumferentially-directed grooves (54) in the respec¬ tive segments for receiving the cable as shown in Figs. 3 and 4. In order to prevent undesirable tipping or cock- ing of the segments, the segment end portions are relieved radially inwardly at (56) and thus out of immediate con¬ tact with the cable in order to prevent undesirable cir¬ cumferential spreading of the gap during the occurrence of high spots on the rotating shell. When the end portions of neighboring segments are in assembled and operative relationship, the two faces (40) contact each other in such manner as to provide a leak- proof interface. Each end portion at its end that cooperates with its neighbor to form the gap (42) is so configured that the gap has an interior relief or mouth (501; i.e., the gap is widened at its contact area with the outer surface of the shell. In the present case, this mouth results from the forming of the end portions respec¬ tively with convergent edges (60); i.e., these edges slope radially outwardly to meet straight parallel edges (.62) that together provide a radial channel (64) that opens at the outer periphery of the segmented ring.

Unless sealed, of course, material would enter the mouths and exit at the outer ends of the channels. To prevent this, the invention combines with the novel mouth and channel arrangement a novel seal element, here in the form of an elastomer block (66).. The segment end portions are appropriately notched at (68) and combine to receive and contribute to mounting the block. In that form of the invention shown in Figs. 1-6 and 8, the notches extend

axially through the respective segments. As to one seg¬ ment, the block is retained by abutting the adjacent fixed ring (.50) and as to the neighboring segment, the block is retained by a retainer element or tab (70) hingedly or detachably secured by a screw (72) to the associated segment.

In a modified form as shown in Fig. 7, neighboring segments (36') are provided with notches (68') to re¬ ceive a seal block (66'). In this case, one notch opens all the way through so that the block abuts the asso¬ ciated fixed ring (50) as before but the other notch is "blind"; i.e. does not open through the segment and hence the tab or retainer is not required.

In a further modified form of the invention, the segmented ring may be constructed as before, except that in this case neighboring segments (36") are notched to receive a block (56") at the open end of the channel that is sealed by the block (66") . The purpose of the blocks (56") at the segment junctions is to receive the cable in such manner as to concentrate the cable tension more to the radially central area of the segments and thus to prevent spreading of the segments..

In all forms of the invention, it is significant that the sealing blocks are disposed at the respective junc- tions of the mouths (58) and associated channels (64) so as to confine material to the space bounded by the con¬ vergent mouth edges and block, thus preventing the mate¬ rial from passing the blocks and perhaps packing in the channels. The segments are preferably made of some suitable non-metallic material such as epoxy-impregnated cloth, which is found to possess substantial low-friction and long-wear characteristics. The block may be made of any suitable elastic having the qualities of long wear and sufficient flexibility as to accommodate "floating" of the neighboring segments spanned thereby. In that

form of the invention of Figs, 1-6 and 8, removal and replacement of blocks because of wear and the like is facilitated by the detachable or hinged tabs.

Features and advantages of the invention, other than those specifically noted herein will become apparent to those versed in the art, as will many modifications and alterations, all without departure from the spirit and scope of the invention.