US2817908A - Yankee drier - Google Patents

Description

Dec. 31, 1957 L. HoRNBosTl-:L 2,817,908

YANKEE DRIER Filed Aug. 19, 1954 5 Sheets-Sheet 1 Dec, 31, 1957 LpnoRNBos-rEL. 2,817,908

YANKEE DRIER Filed Aug. '19. v1954 5 sheets-sheet s @www m/ w.

Dec. 31, 1957 L. HoRNBosTEL 2,817,908

, mms: DRIER Filed Aug. 19. 1954 s sheetssheet 4 Lloyd' Hom boa z/ YANKEE bRIER L. HORNBOSTEL \\l\ xl W FZ' q- .ff

Dec. 31, 1957 Filed Aug. 19. 1954 w 5 is l Lloyd Hornbolfe/ 4% umm eww United tates llatent "i YANKEE DRllER Lloyd Hornbostel, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Application August 19, 1954, Serial N o. 450,937

17 Claims. (Cl. 34-110) This invention relates to drum roll constructions especially for paper making machines and, more particularly, deals with'the construction of Yankee driers for paper machines having a llexible shim and plate assembly interposed between the cylindrical shell and the axle or shaft carried head members thereof to minimize transmission of stresses therebetween induced while maintaining the shell and shaft in coaxial alignment.

The conventional drier drum includes a cylindrical shell having at its opposite open ends inwardly projecting end flanges. A center shaft or axle is coaxially aligned within the shell having outwardly projecting radial hub llanges. The conventional end heads surround the shaft and are securely boltedto the hub flange and the end llange of the shell. A steam pressure chamber is defined by the shell, the shaft, and the end heads. When steam pressure is introduced into the chamber, the shell bows outwardly between the end llanges, and the end heads bulge between the end llanges of the shell and the hub llanges of the shaft. Then, wet paper to be dried is trained over the outer surface of the cylindrical shell and, due to the loading of the shell and the temperature differential caused by the web paper in the metal of the shell wall, the shell tends to shrink back axially. Then the shell shrinks in radially to swing the flange into an outwardly tilted position causing a weak point on the shell adjacent the end flanges. Due to this weak point, safe operation demanded low operating speeds and low steam pressures resulting in lower drying temperatures which seriously limited drying capacity and production.

This invention now provides a drier drum construction, especially a Yankee drier drum construction, having a llexible section connecting the hub flanges of the shaft and the end flanges of the cylindrical shell. This llexible connection substantially eliminates stress concentration at the flange area on the shell, thereby permitting extremely high steam pressures to be introduced into the drier drum. Due to the increase in steam pressures, heat transferred to the outer shell surface and the paper is greater, thus permitting the drier speed to be increased for greater production.

p In the specific preferred embodiment of the invention, the drier is composed of the conventional Yankee drier drum shell having inwardly projecting annular end flanges inwardly from the ends of the shell, a hollow center shaft or axle coaxially aligned within the shell, oppositely positioned end heads secured to the center shaft, conventional radially extending hub flanges on the end head aligned with the end flanges of the shell, and llexible elements connecting the hub flanges with the end llanges of the shell.

Specifically, the llexible element is composed of a plurality of relatively thin chromium steel rings or shims in superimposed relation which fit snugly in the recesses provided by the laligned llange members of the shell and the heads. Rigi-difying arcuate segment plates extend from the hub recess to similar but smaller arcuate segment plates extending inwardly fromthe endllange recess.v A-

-drum according to the invention;

Patented Dec. 31, 1957 gap is left between the outer andinner segments for reasons which will be hereinafter explained. These segments are disposed at spaced intervals circumferentially around the hub, the large segment alternating circumferentially with shorter segments while the shorter segments alternate circumferentially with larger segments, forming a layer of alternating large and small segments. A plurality of other layers of segment plates are stacked on this layer in such a manner that the large segments overlie the smaller segments of the adjacent layer and the small segments overlie the large segments.

A rim ring lits snugly in the recess provided by the end flanges being bolted thereto to unite one end of the rings and segments with the cylindrical shell, while a hub ring fits snugly in the recess provided by the hub llange uniting the inner ends of the rings and segments to the hub flange. A plurality of links are secured between the rim ring and the hub ring whereby the mid-portion thereof is enlarged to engage the outer layer of segment plates, holding it against bulging caused by the steam pressures in the chamber of the drum of the drier. The inner ring seals the chamber from leakage of steam, and jointly with the adjacent rings supports the cylinder shell from the center shaft. The arcuately formed segment members function only to stillen the rings against outward deflections due to steam pressure inside of the drier drum, yet permit the llexibility necessary for the' purpose intended.

The laminated arrangement of the segments and rings is such as to accommodate relative deliections and expansions of the shell and shaft whereby the thin shims or segments and rings are free to slide relative to each other closing and opening the gap between the outer and inner segments somewhat like the leaves in a conventional leaf spring so as to absorb the dellection without unduly stressing the end llanges due to the bending of the rings. Accordingly, the heretofore weakness in a conventional drier near the flange area is overcome. v

It is then an object of the invention'to provide dru driers with stress-absorbing connections between the axle. and cylinder thereof permitting use of highy steam pressures' drum A further object of this invention is to provide a flexible assembly between the head members and the shell of a drier drum which is composed of cylindrical and arcuately formed segmental shims for containing the steam pressure within the drier drum and supporting the shell from, the head members.

It is a specific object of this invention to provide la drier drum with a laminated arrangement of llexible rings and segmental plates so that the segmental plates and rings may slide radially relative to each other, somewhat likef the leaves in a conventional leaf spring, whereby such action substantially absorbs any stresses emanating from the head members or the cylindrical shell.

Other and further objects of the invention will become apparent to those skilled in the art from the following ydetailed description of the attached sheets of drawings which disclose a preferred embodiment of the invention. On the drawings: v Figure l is a side elevational view with' parts broken away to'show underlying parts in cross section of a drie? 1 Figure 2 is a transverse cross-sectional view taken along line II--II` of Figure 1;

Figure 3 is a fragmentary end view, with parts omitted, taken along line Illlll of Figure l;

i Figure 4 is an` enlarged cross-sectional` detail view taken along line IV--IV of Figure 3;

Figure `5 is a broken-away end-view showing the stacked and staggered relationship Vof `the flexible lshim and plate arrangement;

`Figure 6 is a plan view of the small `outerarcuately formed segment plate;

Figure 7 is a plan view of the large inner arcuately shaped segment plate which lies in the same vertical plane as the small outer segment plate but slightly spaced therefrom to provide a take-up gap;`

Figure 8 is a plan view of the large outer arcuately formed segment plate;

Figure 9 is a plan view of the small inner arcuately formed segment plate which lies in the same vertical plane as the large `outer segment plate but is slightly spaced therefrom to provide a take-up gap;

Figure 10 is a plan view of the innermost shell 'supporting rings;

. Figures 1l through 13 are diagrammatic cross-sectional detail views of thetconventicmal` end head lconstruction of heretoforeknown drier drums showing the different stages of loading thereof, and particularly illustrating the weak pointtnear the flange on theouter shell caused by the transmission of stressesbetween the head members and the shell;.and

Figures 14 through 16 are diagrammatic cross-sectional detail views of the end head construction of a'drier drum embodying the invention herein, particularly'illustrating the manner in which the stresses are absorbed by the flexible assembly disposed between the head member andr the cylindrical` shell, thereby eliminating the'weak point near the shell flange area.

As shown onthe drawings:

As` best` shown in Figure l, numeral 15 generally indicates the drier which is provided with a cylindrical shell or drum 16 being preferably composed of cast bronze with a mirror-like finish on the outer surface, a hollow center shaft or axle 17 of cast` iron or cast mild steel, front andback headmembers of cast irongenerally designated by numerals 18tand 19, respectively, and a flexible supporting and sealing assembly or flexible plate and shimlarangement, generally designated by numeral 20.

,The `head members 18` and 19 are generally dishshaped, having bottom or inner` radial fwalls 25, and conically-formed annular walls` 26 projecting outwardly from the peripheral edges of said radial walls 25. low :trunnions 21 `and-22-are centrally disposed within the dish-shaped heads 18 and. 19extending'outwardly therefrom to permit mounting of the drier for rotational movement. Spiders 23 and 24 extendradially from the respective `trurlnons -214 and .22 and` rigidlyconnect the trunnions to the outer. peripheryvoffannular walls 26 providingvsupport `for the radial thrust loads imposed on the cylindrical shell 16. .Thefhead members 18 and 19 are oppositely disposed coaxiallylwithin vthe shell 16 and rigidly connected together by the hollow axle `or center shaft 17. `Ring flanges 28 of center shaft 17 abut annular shoulders `29 of bottom walls 25 of the` head members `18 and 19 and are `firmly united therewith by bolts 27.

:Radial `wa1ls25 of heads 18 and 19 cooperate with the hollow cylindrical center shaft 17to form a steam distribution chamber 30 which s closed atthe `rear head end. :Accessto theinterior of chamber 30 is had through aperturesll` closed by removable circular manhole covers 321.01, Atheplike.

Steam or any other appropriate heating 'medium is introduced: into chamber 30 through pipe '33, thelatter beingndisposedcoaxially within the hollowy trunnion21. The inlet steam pipe or conduit ,B3-.is providedwithlan inner wall 33a and an outer concentrically disposed wall 33b defining therebetween an insulating area 33e which contains air or some other medium. The outer wall 33h of pipe 33 is radially spaced from the inner walls of the trunnion 21 providing a further insulating area. The inner wall 33a and the outer wall 3311 are spaced from each other and supported from said outer trunnion end by the insulating sleeve member 34 and spaced from one another at the inner end by sleeve 35 which is united by bolts 36 to spacer ring 37, the latter being bolted to the inner end of the trunnion member 21 by bolts or fasteners 38. The double walled conduit 33 and its related spacer g components preclude the transfer of excess heat from the superheated steam introduced into the conduit to the trunnion member 21, thereby permitting the bearing surface of the trunnion member to operate at a much cooler temperature. This feature may likewise be provided in the drum or condensate return of trunnion member 22 ofthe back end head 19as shown.

"The superheated steam, at pressures of around 160 p. s. i., is ejected from the distribution chamber through steam nozzles 39 suitably positioned in the axle wall 17, into the working chamber 40 which is defined by the inner walls of the shell 16, the outer walls of the axle 17, the conical walls 26 of the front and back members, and the flexible member 20 which closes the annular gap G. Access to the interior of chamber 40 is had through apertures 41 disposed in the conical walls 26 of the head members, the apertures being closed by removable manhole covers 42 or the like which are ldetachably fastened to the walls 26 by bolts or other means. Access to the opening 41 is gained between spiders 24 which are covered by substantially triangularly shaped cover plates 43 fastened thereon by bolts 44 or other equivalent means.

The steam condenses near the inner wall of the shell 16 and is picked up by elongated condensate dippers or scoops 44 supported at their opposite ends adjacent the inner shell wall by brackets 45 pending from the opposite annular walls 26 of the head members. A central brace 46 attached at one end to the center shaft 17 and at the other end to the mid-point of scoops`44 provides additional support for the scoops. The condensate, after being picked up by the dippers 44, enters the parallel extending dipper manifolds 47 at points 47a and 47b, and is then taken from the manifold by curved pipes or conduits 48 (Figure 2) through diametrically oppositely positioned apertures in the center shaft 17. Straight section pipes or conduits`49 connect the curved conduits 48 withta drain line 50 which extends coaxially within the hollow center shaft 17 and connects with the discharge steam pipe or conduit 50a which is constructed and supported within the hollow trunnion member 22 of end head 19 similar to thearrangement of inlet pipe 33 and trunnion 21, therebly discharging the condensate out of the cylindrical s ell.

Referring now to Figure 4, the gap G between the end heads and the shell, being of relatively small radial extent, is closed by the flexible laminated shim arrangement 20.

The shell 16 is provided with an inturned end flange 51 inwardly from the ends of the shell forming with the end of the shell an annular recess 52 which is aligned with the outwardly extending radial flange 53 of the end head 19, hereinafter referred to as the hub flange, which denes an annular recess 54. The shell and hub flanges 51 and 53 are connected by three relatively thin chromium steel rings or shims in superimposed relation, including an inner ring 55, a middle ring 56, and an outer ring 57. These rings 55, 56 and 57 fit snugly in the recess 52 on the shell 16 on the outside of flange 51 at their outer peripheral ends and fitsnugly in the recess 54' of the head 19 outside of the flange 53 at their inner peripheral ends.

Large inner rigidifying arcuately formed segment plates 58 extend radially outward from the recess S4 ofpthe head-19'l and' are aligned with small outer segment plates fammes S 59 of equal arcuate extent extending radially inwardly from the recess 52, leaving take-up gaps 60 therebetween. These large inner segments 58 and small outer segments 59 alternate circumferentially with small inner segment plates 61 extending radially outward from the recess 54 and large outer segment plates 62 extending radially inward from the recess 52 as clearly shown in Figure 5. Take-up gaps 63 are provided between the small inner segment plates 61 and the large outer segment plates 62. These alternating segments lie in a single plane to form a ring of shims or fingers. Several such ring assemblies overlie each other in layers with the segments of the adjacent ring assemblies in staggered relation. In this manner a small outer segment 59 of one layer overlaps a large outer segment 62 of the adjacent layer while a small inner segment 61 overlaps a large inner segment 58.

These ring assemblies of segments provide rigidifying shims overlying the rings 12, 13 and 14 and have no function in radially supporting the shell on the head.

A rim ring 64 fits snugly in the recess 52 and abuts the outer peripheral edges of the shims and segment plates while a hub ring 65 ts in the hub recess of the head and abuts the inner peripheral edges of the shims and plates. Mounting bolts and nuts 66 extending through the shell flange 51 and through the rim ring 64 at spaced points tightly clamp the stacked plates and shims between the flange and the ring. Similar mounting bolts 67 extend through the hub flange 53 and the hub ring 65 at spaced intervals therearound to tightly clamp the plates and shims therebetween.

The rim ring 64 carries a radial inwardly projecting reduced portion 68 which forms an annular notch 68a between the shims and plates and the rim ring 64 near the shell flange 51. A similar aligned outwardly projecting reduced portion 69 is carried on the hub ring 65 forming an annular notch 69a between the shims and plates and the hub ring 65. Radially disposed between the rim ring 64 and the hub ring 65 and within the notches 68a and 69a are a plurality of links or backing beams or fingers 70 having at their inner ends a groove 71 adapted to receive the inner rounded end 73 of an adjusting bolt or stud 72 which is threadedly engaged in the reduced portion 69 of hub ring 65. Threadedly engaged in the reduced portion 68 of rim ring 64 is an adjusting bolt or stud 74 similar to bolt 72 having at its inner end a rounded or ball end 75 which is adapted to be received in socket 76 carried at the outer end of link 70.

The midpoint of each link 70 is thickened to form a knob-like or enlarged portion 77 which projects beyond the inner vertical edge of the link 70, engaging the outermost shims, the enlarged portion extending laterally from each side of the link, as shown more clearly in Figure 3, to define a segment of a circumferential beam. Combined, these links 70 form a substantially endless circular beam between the shell and the head which will rigidify the plates and shims against outward bulging caused by steam pressure inside of the drum of the drier. A dust ring cover 120 is secured over the flexible assembly Ztl by cap screws 121 or other suitable fasteners which are threadedly received by the rim and hub rings.

The inner rings or shims 55, 56 and 57 jointly support the shell 16 from the head 19, as well as seal the gap G, preventing the escape of steam from the working chamber 40. However, the rings 56 and 57 may be perforated if desired, since the inner ring 55 is sufficient to seal the gap G, and since the rings 56 and 57 are used solely as assist ing the ring 55 and supporting the shell 16 on the head 19.

The vshims or plates 58, 59, 61 and 62 and the links 7@ do not support the shell from the head. The sole function of the segments and the links is to rigidify rings 55, 56 and 57 against outward deflection due to steam pressure inside of the drier drum without interfering with the flexing of the rings and minimize stress transfer from the drum shaft or axle to the shell. The laminated arrangement of the plates and shims is such as to accommodate relative deflections and expansions of the shell and head and the shims and rings are free to slide over each` other, somewhat like the leaves in a leaf spring so as to accommodate the deflection without stressing the flanges 51 and 53 due to bending of the rings 55, 56 and 57. The flexible assembly 20 functions to seal the gap G preventing any escape of steam and to support the shell 16 from head 19, while preventing the transmittal of stresses from the shell to the end head or from the end head to the shell. The flexible assembly actually absorbs stresses induced by the shell or the end head which prevents the building up of Weak points around the shell flange area and the hub flange area.

While only the flexible assembly 2t) which surrounds the end head 19 has been described in detail, it is to be understood that a substantially identical flexible member surrounds the end head 18 in the same fashion.

Figures 11, l2 and 13 diagrammatically illustrate the stresses induced in a conventional Yankee drier of the prior art. The outer shell 80 is supported from the axle or -center shaft 31 by a solid end head 82 rigidly united to the shell end flange 83 and the hub flange 84.

Figure l1 shows the normal position of all components before the application of any forces.

When the steam pressure is introduced into the working chamber S5, the shell 8d bows outwardly and the solid end head S2 bends `as shown by the solid lines of Figure l2. When the wet paper engages the outer surface of the shell tlf), due to the differential of temperature caused by the cooling off of the shell, it tends to shrink back axially as shown in the dotted lines of Figure 12.

Then the shell 8f) turns in radially at 80a as shown in Figure 13 due to the radial shrinkage to swing the end shell flange S3 into an outwardly tilted position, while the solid end head 82 bulges outwardly in resisting the internal steam pressure. Due to the rigidity ofend head 82, the shell flange area is weakened, causing failures and fractures in the metal as ydesignated by the numeral 80h of Figure 13. The present invention has obviated this undesirable situation.

Figures 14, 15 and 16 illustrate the operation of the invention herein claimed and described with special reference to the function of the flexible member, and how the shell stresses at the flange areas have been relieved. In the invention, the steam chamber 86 is bounded by the inner walls of shell 87, the outer walls of the center shaft or axle 88, and the flexible member 89. The flexible member 89 is seated against end shell flange 9@ and the hub flange 91 and clamped between end flange 90 and the rim ring 92 at one end, while the other end is clamped f between hub flange 91 and hub ring 93. The arrow 94 denotes a fixed midpoint comparable to the beam formed by the plurality of links 70. The flexible member includes an inner sealing and supporting member 95, outer large and small segment plates 96 and 97, respectively, and inner large segment plate 98 and inner small segment plate 99. Between the outer large segment plate 96 and the inner small segment plate 99 is a gap 100, while between the inner large segment plate 98 and the outer small segment plate 97 is a small gap 101. These figures, being generally diagrammatic in illustration, show only those components necessary to provide an adequate explanation of the functions. For example, the inner ring 95 is equivalent to the rings 55, 56 and 57. It is seen then that, for reasons of simplicity and clearness, the number of shim end plates have been reduced.

Figure 14 shows the components of the Yankee drier in normal position before any loads or forces have been applied.

At the first stage, when the steam is introduced into the chamber 86, the shell 87 bows outwardly, and the flange of the shell, due to the great flexibility of the supporting member, follows the movement of the shell, as shown in black in Figure l5 When the wet paper is applied to the outer surface of shell 87, the flange will shrink back 7 as shown in dotted form along the axis of the shell, pulling the outer edge of the flexible member inwardly.

In Figure 16, it is seen that the flange 90 and adjacent shell area returns to a substantially normal position when the outside diameter of the shell shrinks due to the temperature differential of the metal in the shell wall. The outer edge portion of the flexible member 89 responds to the axial and radial movements of the shell 87 because of its great flexibility; and since the shell wall is not restricted to its movement to any material extent by the flexible member, the stresses around the flange area are materially reduced or completely eliminated. While the shim and link backed shell supporting plates maydeflect and bulge, the shell will remain concentric with the shaft.

It is seen that applicant has invented a novel drier drum construction wherein a flexible non-stress transmitting end head assembly supports the drum shell from the drum axle while also scaling the steam chamber in the shell. The combined flexible support and seal accommodate high speed operation and high steam pressures within the working chamber resulting in increased paper drying capacity.

It will, of course, be understood that numerous details of lconstruction may be varied through a wide range without departing from the principles of this invention, and it is, therefore, not the purpose to limit the claimed invention herein otherwise than as necessitated by the scope of the appended claims.

I claim as my invention:

l. A drier drum comprising a cylindrical shell defining the working surface of the drier, a center shaft coaxially aligned within said shell, front and back head members in coaxial relation to said shell and firmly united to the opposite open ends of the 4center shaft, and flexible supporting and sealing means interposed between the inner circumferential edge of the shell and the outer circurn* fercntial edge of the head members including, at least one plate ring spanning the space between the head and shell and a plurality of arcuate segmental shims overlying the plate adapted to slide radially to each other and absorb the stresses induced in said head members.

2. A drier drum construction comprising a cylindrical shell with inturned flanges inwardly disposed from the open ends thereof, an axle with head members secured to its opposite ends coaxially aligned within said shell, outwardly projecting radial flanges on said heads aligned but spaced inwardly from the shell flanges, flexible end members supporting said shell from said axle as well as sealing a medium within said shell, said flexible end members comprising rings and segmental plates arranged in stacked and staggered relation to function as stress relievers of the shell.

3. A drier drum construction comprising `a. cylindrical shell with inturned flanges inwardly disposed from the open ends thereof, an axle with head members secured to its opposite ends coaxially aligned within said shell, outwardly projecting radial flanges on said heads aligned but spaced inwardly from the shell flanges, flexible end members supporting said shell from said axle as well as sealing a medium within said shell, said flexible end members comprising at least one inner ring, and a plurality of seg mental plate layers arranged in superimposed relationship adjacent the ring, whereby the inner ring contains the steam pressure within the shell from the axle, while the plate layers rigidity the ring, yet the combined unit is eapable of rclic=.'ing in the shell flange area.

4. A drier drum comprising a cylindrical shell having inwardly extending flanges spaced slightly inward of the shell ends, an axle within the shell having an end head fastened to each end thereof, radialllanges projecting outwardly from the end heads and aligned and spaced inward-- ly from the shell flanges, and a'flexible shim and plate assembly adapted to support the shell from the axle toprovide a steam tight fit between the end heads and the shell, and relieve stresses around the shell flanges.

5. A drier drum end. head assembly including a flexibleV shim and plate assembly comprisinga plurality of inner stresses shims functioning to support the drum shell from the drum axle and contain the steam within the shell, and at least one layer of rigidifying plates abutting the shims, a shell ring clamping the outer edges of the shims and plates to the shell flange, a hub ring clamping the inner edges of the shims and plates to the head flanges, and a link beam held at opposite ends to the rings abutting the outermost plates for preventing them from bulging outwardly due to the steam pressure.

6. Infa steam drum having end heads and a shell surrounding the heads in spaced concentric relation therewith, the improvements of flexible sealing and supporting ring assemblies between the heads and shell, each assembly including an inner flexible sealing and supporting ring plate, layers of shims overlying the plate, and radial fingers between the shell and heads overlying `the outer layer of shims and adapted to abut the radial mid points of said outer layer, means on the heads and shell overlying the fingers to clamp the fingers against the shims without transmitting radial load to the fingers, each layer of shims being composed of head carried segments and shell carried segments with gaps therebetween, and the segments of adjacent layers being in face-to-face sliding contact.

7. An end head construction for drum driers comprising a relatively thin flexible plate adapted to support a drum shell and confine steam under pressure in the shell, shims overlying said plate in slidable relation to stillen the plate against bowing under the influence of steam pressure without supporting the shell, and said shims being relatively slidable over each other.

8. An'end head construction for drier drums which comprises,a `relatively thin flexible ring adapted to support a drum shell and confine steam under pressure in said shell, a plurality of segmental annular members overlying said ring in slidable relation to rigidify the ring against outward bulging caused by the steam pressure without supporting the shell, and said annular members also being relatively slidable over each other.

9. An end head construction for drier drums comprising 'a plurality of stacked flexible rings in slidable relation adapted to support a drum shell from a drum shaft and confine steam under pressure within said shell, and a plurality of arcuately formed segments overlying said rings in slidable relation to rigidity the rings against outward bulging caused by the influence of steam pressure without supporting said shell, said segments also being relatively slidable over each other.

lO. An end head construction for drier drums comprising a plurality of stacked flexible rings in slidable relation adapted to support a drum shell from a drum axle and confine steam under pressure within the drum, and a layer of arcuately formed segment plates overlying said rings in slidable relation to rigidify the rings against outward bowing caused by the steam pressure without supporting said shell.

ll. An end'head construction for a drier drum comprising at least one flexible ring adapted to support a drum shell from a drum axle and confine steam under pressure within the shell, and a plurality of layers of arcuately formed segment plates with equal arcuate extent overlying said ring in slidable relation to rigidify the ring against outward bulging caused by the steam pressure, said layers including a small inner plate and a large outer plate radially aligned and spaced at circumferential intervals around the cnd heads alternating with radially aligned abutting large inner plates and small outer plates.

l2. An end head construction for a drier drum comprising at least one flexible ring adapted to support a drum shell from a drum axle and confine steam under pressure within the shell, and a plurality of layers of arcuately formed segment plates with equal arcuate extent overlying said ring in slidable relation to rigidity the ring against @inward bulging caused by the steam pressure, said layers including a small inner plate and a large outer plate radially aligned and spaced at circumferential intervals' around the end heads alternating with radially aligned abutting large inner plates and small outer plates, wherein the adjacent layer of plates is staggered circumferentially so that a large inner plate completely overlaps a small inner plate and partially overlaps a large outer plate while the latter is also overlapped by a. small outer plate.

13. An end head construction for a drier drum comprising at least one flexible ring adapted to support a drum shell from a drum axle and confine steam under pressure within the shell, and la plurality of layers of arcuately formed segment plates with equal arcuate extent overlying said ring in slidable relation to rigidify the ring against outward bulging caused by the steam pressure, said layers including a small inner plate and a large outer plate radially aligned and yspaced at circumferential intervals around the end heads alternating with radially aligned abutting large inner plates and small outer plates, and a relatively small arcuate take-up gap is provided between the plates in the same plane, whereby said plates may slide towards each other.

14. A drier drum comprising a cylindrical shell, a center shaft coaxial with the shell, head members on said shaft, flexible ring assemblies extending radially from said head members to said shell for simultaneously sealing and supporting the shell to retain steam pressure therein, said assemblies being capable of dellecting under load and preventing the transmission of stresses from the head members to the shell, and support members engaging said flexible assemblies intermediate the shell and head.

15. A drier drum construction comprising a cylindrical shell with inturned anges inwardly disposed from the open ends thereof, a hollow axle, head members secured to opposite ends of the axle and coaxially aligned with said shell, outwardly projecting radial ilanges on said heads aligned but spaced inwardly from the shell flanges,

tiexible end members supporting said shell from said axle as well as sealing a medium within said shell, whereby said liexible end members materially relieve the stresses around the llange area, and support members engaging said ilexible members intermediate the shell flanges and head flanges.

16. A drier drum comprising a cylindrical shell member, a center shaft coaxial with the shell, head members on said shaft, ilexible ring assemblies extending radially from said head members to said shell for simultaneously sealing and supporting the shell to retain steam pressure therein, said assemblies being capable of deilecting under load and preventing the transmission of stresses from the head members to the shell, and rigid ring means carried by one of said members engaging said flexible assemblies along a region spaced from said shell and said head members. f

17. A drier drum comprising a cylindrical shell member, a center shaft coaxial with the shell member, head members on the shaft, a sealing closure at each end of the shell for an annular steam pressure chamber between the shell and shaft comprising at least one radially and circumferentially continuous llexible metallic membrane extending between said shell and a head member, and at least two overlying circumferentially and radially noncontinuous membranes mounted around said members supporting said continuous membrane in a substantially radial plane, such that the shell member is concentrically supported relative to its central axis without momental restraint against pressure and temperature deformations.

References Cited in the tile of this patent UNITED STATES PATENTS 1,637,327 Atkins Aug. 2, 1927 2,328,321 Berry Aug. 31, 1943 2,628,433 Ostertag Feb. 17, 1953

Images