US2522993A - Seal for driers - Google Patents

Description

J. R. COFFEY SEAL FOR DRIERS sept. 19, 195o Filed Dec.

2 Sheets-Sheet l J. R. COFFEY SEAL FOR I DRIERS Sept. 19, 195o 2 Sheets-Sheet 2 Filed Dec. 12, 1947 INVENToR.

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N @www Patented Sept. 19, 1950 i UNITED STATES PATENT OFFICE` `2,522,993

SEAL FOR DRIERS James R. Coffey, deceased, late of Louisville, Ky., by Ursula Coey, administratrix, Louisville,

Ky., assignor to lGeneral American Tranportation Corporation, Chicago, Ill., a corporation of New York Application December 12, 1947, Serial No."791,414 e (Cl. 285-.-10) i 1.2 Claims. l

This invention relates to air seals for dryers and has for its principal object the provision of a new and improved device of this kind.

It is the main object lof the invention to provide an improved air seal for rotary, cylinder type dryers.

Another object of the invention is to provide a seal for sealing space between the outer shell of a rotary, cylinder type dryer and tempering chambers and discharge hoods into which the shell projects.

Another object of the invention is to provide a circumferentially flexible seal* composed of a plurality of individual rigid members articulated together.

Another object of the invention is to provide an air seal for dryers of this type which can be manufactured at low cost without sacrificing quality, and can be maintained in proper Working condition economically.

Further objects of the invention not specically mentioned here will be apparent from the detailed description and claims which follow,

reference being had to the accompanying drawings in which a preferred embodiment of the invention is shown by way of example and in which:

Fig. 1 is a side elevational View of a dryer` showing the seal applied thereto;

Fig. 2 is a fragmentary elevational View of a seal drawn to en-larged scale;

Fig. 3 is a cross sectional view taken substantially along the lines 3-3 of Fig. 2 looking in the direction of the `arrows and drawn to an enlarged scale; and

Fig. 4 is a fragmentary plan View partly taken substantially along the lines 4 4 of Fig. 3 looking in the direction of the arrows.

Cylindrical dryers are frequently used to dehydrate comminuted material down to a low moisture content. Usually these dryers consist of a cylindrical drum rotatably mounted and rotated at slow speed about its longitudinal axist Within the drum are lifting and showering media and sometimes' steam `pipes for heating,` so that material fed into the drum will be tumbled and showered therein and will move from end to end thereof and be dehydrated during such movement. Usually the inlet end of the dryer shel-l is somewhat higher than the outlet end to facilitate movement of the material therethrough.

Frequently the inlet end of the dryer is projected into a tempering chamber wherein air or gas is heated, dried -and/or otherwise prepared for movement through the dryer. The conveyors or chutes :by which the material to be driedis" fed into lthe dryer also extends through this tern-r pering chamber. The outlet end of the dryer# also extends into a box-like structure or discharge hood which receives the material emerging from f the dryer and empties into the conveyor or other"l means by which this material is carried away from the dryer. i

In certain instances the air in the tempering."` chamber is maintained above atmospheric presl sure so as to force a stream of air through thedryer and in intimate contact with the material y tumblingtherein. In other instances an exhaust fan is connected to the discharge hood to reduce` the pressure therein and thereby induces a ow' of air through the dryer. In other instancesbothl arrangements may be used.

It will be apparent that the large diameter cylindrical shell of the dryer which is constantly i' rotating during operation of the dryer cannot? be tightly fitted into the walls of the tempering .i and discharge chambers, but rather an appre-` ciable space must be left therebetween. It will"V also be apparent that if the space around the'l shell at the point of its entry into the tempering chamber is not lblocked or sealed, the pres-I sure in the tempering chamber will force a con-` tinuous stream of air through this space and the efciency of the dryer will thereby be de#` creased. Similarly if the space between the end 1' of the dryer and the discharge hood into whichv it projects is not sealed, vacuum in the discharge hood will draw air through that space thereby partially short-circuiting the dryer and withaconsequent reduction in the volume of air flowing therethrough to the detriment of the drying operation. It is to the sealing of these spaces*L that the present invention particularly relates. The cylinder shells of dryers of the type to which the invention refers are of large diameter, 1 frequently seventy-two inches or more, and al-` though these drums are accurately made it will be apparent that there is apt to be considerable variation from a true cylinder in the shell. The

if sealing element therefore must be flexible through a range suiciently great to permit sealing notwithstanding these irregularities in the shell conguration. i

Referring now to the drawings in more detail', the dryer consists of a cylindrical shell IU containing bearing rings II that register with suitable rollers I2 that support the shell with its axisv substantially horizontal. Rollers I2 are mounted 1 on suitab-le bases I3 and the right-hand one of* these bases as seen in Fig. 1 is preferably somewhat higher than the left-hand base so as to elevate the inlet end of the dryer above the outlet end. The shell also carries a ring gear I4 With which is meshed a pinion i5 that is driven by a suitable source of `power such as a motor I6 thr-ough speed-reducing gearing I1 to rotate the dryer.

Within the dryer are lifting nights or shelves,

and/or steam pipes and baffles, the particular f type and arrangement of which form no part of the present invention. l

At the right or inlet end of the dryer, as seen in Fig. l, is a generally rectangular box-like structure usually referred to as a tempering chamber, and the end of the dryer shell il! projects into and part-way through the walls of this chamber. Within the chamber there may be located air cleaning and heating equipment, or if desired such equipment may be located externally of the chamber to discharge into it. The dryer cylinder may project into the tempering chamber through one wall of the latter, or'may extend entirely through said tempering chamber by projecting through two opposite walls, and the conveyor or chute equipment by which the material to be dried is introduced into the dryer, may or may not enter the tempering chamber. Since this tempering and feeding equipment forms 'no part of the present invention, it has been omitted from the drawings to avoid-unnecessary complication thereof.

At the left or outlet end of the dryer wall i0 is a similarly generally rectangular structure 30 commonly referred to as a discharge hood and out of the bottom of which a conveyor 3! leads to carry off the dried material received by the. Y hood. A suitable duct 32 may lead out of the top of the discharge hood and to an exhaust fan, not shown, by which air is drawn out of the hood. Or a duct from a furnace or heater may 'be attached to the discharge hood 3l), in which case the du-ct 32 leading to the exhaust fan is attached to the tempering chamber or to a stationary housing called a feed hood or throat piece. Generally the exhaust fan will discharge into a suitable dust collector such as a cyclone, so that minute particles of the product drawn out of the hood with the air current can be reclaimed. This equipment forms no part of the present invention and has been omitted from. the drawings to avoid unnecessary complication thereof.

The seals 35 and 36, mounted upon the discharge hood and tempering chamber walls respectively, encircle the shell I0 of the dryer and serve to seal the space between this shell and the chamber walls. It is this seal to which the invention particularly relates.

As will be seen in Figs. 2, 3 and 4, the seal consists .of a stationary ring 4|]` having ears 4i projecting radially from its outer edge, these ears being perforated to: permit attachment of the ring to the wall 42 of the housing 20 by suitable means such as stud bolts 43. The inner edge of the ring 40 is concentric with the shell I0 of the dryer and coincides with the innermost edge of the opening in the wall 42 through which this dryer shell projects. Ring 40 contains a plurality of threaded openings 44 into which studs 45 are threaded. The surface of the ring 40 away from the wall 42 projects beyond the corresponding surface of the ears 4l and is machined smooth and flat so as to facilitate forming the seal.

Mounted upon this ring are a plurality of shoe sections rwhich together form an articulated ring that is disposed concentrically of the shell I 0 and ring 401. Each of these shoe sections consists of an annular portion 5D which contains a flange 5| on its inner edge. The flange is formed as a section of a cylinder Whose diameter is slightly greater than the diameter of the shell l0. The annular portion 5t of the shoe section contains a perforation 52 through which the stud bolt 45 projects. A washer 53 ts over the stud and against the annular portion 5S and is pressed thereagainst by a spring 54 that is tensioned by nuts 55 threaded on the stud. Spring E4 presses the annular portion 5) tightly against the ring 40, and maintains it in sealforming engagement therewith. Since the perforation 52 in this annular portion is substantially greater than the diameter of the stud, it will be apparent that limited movement of the shoe with respect to the ring 4B is possible.

As shown in Fig. 3, the wall 42 of the tempering chamber is'assumed to be composed of masonry or concrete, and a sealing surface thereon is formed by the ring 4I). In certain instances the walls of this chamber may be composed of metal which is smooth enough to form a seal with the shoe portion 5D. In such instances the studs 45 may be threaded directly in the wall of the chamber and the ring 40 omitted.

As Awill be seen best in Fig. 4, the one end of the annular portion 50 of the shoe is bent out of the plane of the remainder of that portion in the direction of the flange to form an ear 56, Iwhich projects beyond the end of the flange 5! of the shoe and overlaps the end of the adjacent shoe. This `overlapping of the shoe sections in the portions thereof in engagement with the ring 40 facilitates maintaining a, seal therewith throughout the range of movement of the individual shoe sections.

Mounted upon the Iianges 5I of each shoe section is a sealing member 60* which may conveniently be composed of a fibrous material impregnated in the manner of ordinary brake lining. As shown, this material is attached to the flange by rivets lcountersunk therein, although other forms of attachment may be used. As will be seen in Figs. 2 and 4, the lining 50 is terminated short of the end B2 of the flange 5I adjacent the ear 55, as shown at 63, and projects beyond the flange 5l at the opposite end of the shoe as shown at 64. By this overlapping of the flange and seal-forming member, a tight seal can be maintained throughout the range of movement of the shoe sections with respect to each other.

Fixed to and projecting from the annular portion 50 of each shoe and in juxtaposition to flange 5l thereon is a post 65 on the outer end of which is formed a hook 66. These posts and hooks 55 and B6 are located adjacent each end of the shoe. Also mounted upon the annular portion 50 of each shoe adjacent each end thereof is a second hook 68.

Springs 6'! and 69, which may be coil springs, are attached to posts and hooks 65 and 68. As shown, spring 61 may be attached at one end to the inner post 65 on one section and at the other end attached to the outer post 63 of the adjacent section, and spring 69 may be attached to the outer post 63 of the first section and at the opposite end to the inner post 65 of the second section. As will also be seen in Fig. 2, spring` 61 may be attached at both ends to posts 65 of adjacent Sections, and spring 69 attached at both ends nto posts 68 of those sections. lilither` .ar-y

rangement mayfbe used, and in certain instances both :may be used to form a'seal.

`Springs 61 and 69 are tensioned to draw the adjacent shoe sections togethen and i, are therebyttensioned to draw the seal-.forming members 60 into tight engagement with the outerj surface of the shell l0. The seal so formed .effectively blocks the opening between the rotating AShell le andfthestationary housing into which it projects, preventing the entrance of air throughA` k drum, or between the annulus 50 and the ring 40.

It has. been found that dryers equipped with the seals of the present invention have operated more. efciently because of the minimizing of the entrance or escape of air or gas from the system.

From the foregoing, it will be apparent that the sealing device ofthe present invention consists ofaplurality of short rigid sections which are individually mounted and are connected together toform an articulated ring which is flexible circumferentially. The individual sections are movable through a limited range,`both with respect to each other and with respect to the lmember on which they are mounted, and this movement is achieved without breaking the seal.

said shell, and means interconnecting adjacent ones of said rigid members for urgingthey same together to thereby urge said seal-forming members into seal-forming engagement with said shell.

2. The combination with a dryer having a .oye

lindrical shell which is rotatable and a stationary housing into which the shell projects, of a seal for closing the space between the housing and the shell comprising, a ring fixed upon the housing concentrically of the shell and having an in,- side diameter greater than the outside diameter of the shell, a plurality of rigid members of L cross section and having an annular portion and `The sealing device of the present invention possesses many advantages. Thecombination of a fixed ring permanently mounted Vupon the stationary housing and carrying an articulated ring composed of a plurality of individual rigid shoes each of which bears a sealing member that is of it, such embodiment has been by Way of eX-i,

ample only, as there are many modifications and adaptations which can be made by one skilled in e the art Within the teachings ofthe invention.

Having thus complied with the statutes and shown and described the preferred embodiment of the invention, what is considered new and is to be protected by Letters Patent is pointed out in the appended claims.

What is claimed is:

1.` The combination with a dryer having a cylindrical shell which is rotatable and a stationary housing into which the shell projects, of a seal for closing the space between the housing and the shell comprising a ring fixed upon the housing concentrically of the shell and having an inside diameter greater than the outside diameter of the shell, a plurality of rigid members of l. cross section and having an annular portion and an arcuate portion, each of which members contains a perforation in its annular portion, studs fixed on said ring and each projecting through the perforation in one of said members, the diameters of said studs being substantially less than the diameters of the perforations to permit limited movements of the members with respect to the ring, seal-forming members fixed to the arcuate portions of the rigid members and engaging an arcuate portion, each of which members contains a perforation in its annular portion, studs fixed on said ring and each projecting through the perforation in one of said members, the diam.-

eters f said studs being substantially less than the diameters of the perforations to permit limited movements of the members with respect to the ring, seal-forming members iixed to the arcuate portions of the rigid members and engaging said shell, and means including springs encircling said studs and nuts threaded thereon and engaging said springs for maintaining said annular i uniform distance therefrom, a plurality of inter.-

leaved rigid arcuate members disposed upon the ring and projecting therefrom radially inwardly toward the shell, each of said members being L- shaped in section and being mounted on the ring for limited movement with respect thereto, a sealforming member attached to each of said members and engaging said shell and spring means interconnecting adjacent ones of said members' and tensioned to hold said seal-forming members in sealing engagement with said shell.

4. The combination with a dryer `having av cylindrical shell which is rotatable and a stationary housing into which the shell projects, of an air seal for closing the space between the housing and shell comprising, a ring xed upon the housing and encircling the shell at a Substantially uniform distance therefrom, a plurality of interleaved rigid arcuate members disposedupon the ring and projecting therefrom radially inwardly toward the shell, each of said members being L-shaped in section and being mounted on the ring for limited movement with respect thereto, a seal-forming member attached to each of said members and engaging said shell and spring means for maintaining said arcuate members in seal-forming engagement with said ring.

5. An air seal for a rotatable cylindrical dryer shell comprising, a fixed annulus encircling the dryer and spaced therefrom, a movable multisection annulus disposed against said fixed annulus and encircling said dryer, means for supporting the movable annulus on said Xed annulus, said means permitting limited movement of the movable annulus with respect to the fixed annulus, seal-forming means carried by the movable annulus and engaging the dryer shell, and spring means carried between adjacent sections of the movable annulus for urging said sealforming means into seal-forming engagement with the dryer shell,

6. A seal as claimed in claim in which the seal-forming means is in sections corresponding in number and length with the annulus sections and fixed to said annulus sections in oiset relation thereto so that a portion of each annulus section overlaps the seal-forming means on an adjacent annulus section.

"7. A seal as claimed in claim 5 in which each section of the multi-section annulus is of L section and has anl annular portion engaging the xed annulus, which annular portion has an end section that is offset from the remainder of the portion and overlaps the annular portion of an adjacent section.

8. A seal as claimed in claim 5 in which each section of the multi-section annulus lis of L cross section and has an annular portion engaging the xed annulus, which annular portion has an end section that is offset from the remainder of the portion and overlaps the annular portion of an adjacent section and in which the sealforming means is in sections with each section iiXed to a section of the multi-section annulus in oirset relation thereto and projects from the end thereof opposite said end section and is overlapped bythe end section of an adjacent annulus section.

l9. The combination with a dryer havingr a cylindrical shell which is rotatable and a stationary housing into which the shell projects, of a seal for closing the space between the housing and the shell comprising, a stationary ring xed on the housing concentrically of the Shell, a flanged articulated ring encircling the shell, means securing the articulated ring in seal-forming engagement with the stationary ring, said securing means permitting limited radial and circumferential movement of the articulated ring with respect to the stationary ring, seal-forming means xed on the flanges of the articulated ring, and means carried by the articulated ring for moving said ring with respect to the stationary ring to maintain said seal-forming means in seal-forming engagement with said shell.

10. The combination with a dryer having a cylindrical shell which is rotatable and a stationary housing into which the shell projects; of a seal for closing the space between the housing and the shell comprising: a stationary ring mounted on the housing concentrically of the shell, an articulated ring encircling the shell and disposed against the stationary ring, means securing the articulated ring in seal-forming engagement with the stationary ring, said securing means permitting limited radial and circumferential movement of the articulated ring with respect to the stationary ring, seal-forming means carried by the articulated ring and engaging the shell, and means for holding said sealforming means in seal-forming engagement With the shell.

l1. The combination with a dryer having a cylindrical shell which is rotatable and a stationary housing into which the shell projects, of a seal for closing the space between the housing and the shell comprising: a stationary ring mounted on the housing concentrically of the shell, an articulated ring encircling the shell,

f means securing the articulated ring in seal-forming engagement with the stationary ring, said means permitting limited movement of the articulated ring with respect to the stationary ring, seal-forming means on the articulated ring, and means carried by the articulated ring for maintaining said seal-forming means in seal-forming engagement with said shell.

12. A circumferentially flexible air seal for closing the space between a fixed housing and a cylindrical shell rotating within an opening in said housing, comprising an articulated ring encircling said shell consisting of overlapping arcuate segments, each section having an annular portion for attachment to the wall of the xed housing; spring means attached between and on the annular portion of adjoining segments for forcing them inwardly; a seal-forming means between said ring and shell; studs xed in the said housing for fastening the annular portions of said segments to the housing; a perforation in the annular portion of each segment for the insertion of said studs, which perforation is larger than the studs to permit limited movement therein, and spring means encircling said studs for maintaining the section in seal-tight engagement with the housing during said movement.

URSULA COF'F'EY. Administratrice of the Estate of James R. Coffey,

Deceased.

REFERENCES CITED UNITED STATES PATENTS `Name Date La Roza Dec. 8, 1936 Number

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