US2697284A - Double shell drier roll construction - Google Patents

Description

Dec.`2l, 1954 E, 1 CHARLTON ET AL 2,697,284

DOUBLE SHELL DRIER ROLL CONSTRUCTION Filed sept. 1, 195o QW NY MY Qm.

....... #NW2/I NWQRS BY @y Y'm TTORNEYS Uite 2,697,284 Patented Dec. 21, 1954 Donata sanft Duran noti. coNsrnUcrIoN Edward l. Charlton, Coatesville, and Leonard Pompa, Philadelphia, Pa., assiguors to Lukens Steel Company, Coatesville, Pa., a corporation of Pennsylvania Application September 1, 1950, Serial No. 132,824

7 Claims. (Cl. 34--124) This invention relates to drier rolls or drums, and the (iinvention is concerned with structural features of such rums.

Drier rolls or drums of the kind with which the invention is concerned are adapted for use, for example, in the paper making industry. These drums are frequently of quite large size, for example, live or six feet in diameter and often of length equal to several times the diameter. Because of the relatively great weight of such rolls in relation to the diameter thereof, the rolls are subjected to unusually severe flexural stress. Moreover, the drums are subjected to various other stresses, notably those arising as a result of expansion and contraction due to changes in temperature.

The invention is especially concerned with the double shell type of dried drum which commonly comprises a pair of journals arranged at the ends of the drum and a double drum wall providing an annular space adjacent the cylindrical working surface of the drurn through 1whih a heat transfer medium, such as steam, is circuate The present invention is primarily concerned with a novel hub structure for drier drums of the kind referred to, the hub structure of this invention providing for support of the drum wall on the journals in a novel manner characterized by unusual ruggedness and capability of withstanding the strains set up as a result of thermal expansion and contraction and the severe flexural stress due to the extreme weight-to-diameter ratio.

More specifically, the various elements of which the hub structure is made up are arranged to provide fabrication thereof from rolled steel plate elements which are preferably welded to each other, to the journals and to the drum walls.

The plate elements of the hub structure are further arranged to provide a broad base of interbracing between the journals and the drum walls, so as to minimize deflection of the projecting end portions of the journals under the influence of the heavy loads or weight carried thereby.

In considering another aspect of the invention, it is first noted that in double shell steel drier drum construction it has been common to provide passages for the heat transfer medium extended through the journals themselves and to provide piping internally of the drum as a whole interconnecting journal passages with the annular chamber adjacent the outer drum wall. According to the present invention certain of the plate elements of the hub structure are arranged to serve not only for interbracing the journal and the drum walls but also to provide communicating passages between the annular chamber at the drum surface and flow passages provided in the journals.

For the above purpose certain of the plate elements are arranged to define flat hollow spokes between the journal and the drum walls. The llat spokes are posi tioned with their major cross sectional axes extending in planes containing the drum axis, and in this way the inter-spoke spacing is relatively large and this facilitates joining of the spokes to the journal and provides large spaces for convenient access to the interior of the drum.

Still other objects of the invention include arrangement of the plate elements of the hub structures so as to simplify fabrication and assembly of the drum, including the interconnection of various of the parts by welding.

How the foregoing and other objects and advantages are attained will appear more fully from the following description referring to the accompanying drawing, in which- Figure l is an axial sectional View of a double-shell drier drum constructed according to the present inven tion;

Figure 2 is a side elevational view taken from the right of Figure l; and

Figure 3 is a partial transverse sectional view, on an enlarged scale, taken as indicated by the section line 3-3 applied to Figure l.

'Ihe drier drum illustrated in the gures of the drawing includes a pair of journals 4-5 projecting from the ends of the drum and serving to mount the drum for rotation. The drum has a double wall, the outer wall being indicated at 6 and the inner wall at 7, there being an annular chamber between the two drum walls to provide for circulation of a heat transfer medium, commonly steam. rlhe journals and the drum walls are intercon4 nected by intervening hub structure now to be described.

First note that the two journals have portions 4a and 5a projecting into the ends of the drum. Each of the hub structures is made up of a plurality of interconnected plate elements including an outer plate 8 and an inner plate 9 lying in planes perpendicular to the drum axis and centrally apertured to receive the inwardly projecting portion of the associated journal. Plates and 9 are spaced from each other axially of the drum, the outer one (3) being disposed close to the end of the drum wall 6 and the inner one close to the inner end of the associated journal. The pairs of plates 8 and 9 are also provided with cut-outs or apertures such as indicated at 10 in Figures 2 and 3, to provide a plurality of spokes 11, the spokes of the pairs of plates 5 9 being in axial alignment with each other.

Additional pairs of plate elements 12-12 are incorporated in each of the hub structures, these plates lying substantially in planes containing the axis of the drum and being arranged to intervene between the spokes ll of the plates 8 and 9. Plate elements 12 are apertured intermediate the edges thereof and these apertures are flanged or flued as at 13, with the ilanges on the plates of cach pair turned inwardly toward each other to substantially abutting relation, as clearly appears in Figure 3.

Attention is now called to the welded joints between the plates of the hub structure, the journal and the drum walls. The lines of welding are mentioned herebelow with reference to the right hand end of the structure as viewed in Figure l.

In considering the welding it may first be noted that access to various regions requiring welding may be had through the relatively large openings 1th in the end plate 8, and the corresponding openings in the inner plate 9. In addition, it is mentioned that the welds or weld joints themselves may be of various types, the invention here not being concerned with the specific form of weld joint used. The representation of the welds on the drawing, therefore, is to be considered as illustrative of appropriate locations for welds but not necessarily illustrative of the specific type of weld.

Plate 9 is desirabiy welded to the inner shell 7 by a weld indicated at 9a extending all the way around the interior of the shell '7. Similarly, a weld 9b is provided between the plate 9 and the journal structure, extending around the latter. Plate 9 may also be welded to the journal structure and to the shell 7 in the regions between the pairs of plates 12-12 as indicated for example at, 9c.

Plate 8 is desirably welded to the inner shell 7 by a weldindicated at 8aV extending all the way around the interior of the shell 7. Similarly, a weld 8b is provided between the plate 8 and the journal itself, extending around the latter. The annular weld 8c interconnects plate 8 and the outer shell 6.

The pairs of plates 12--12 are each welded all the way around the edges thereof as indicated at 12a, thereby connecting these plates with the spokes 11 of both plates 8 and 9, with the inner shell 7 and with the journal structure. Each pair of plates 12-12 are welded to each other at the edges of the uid openings as indicated at 13a.

lt will be noted that the arrangement of the plate elements of the hub structure is such as to dene a series of at hollow spokes interconnecting the journal and the walls of the double shell, with the major cross sectional axis of each spoke extended lengthwise of the drum, i. e., lying in a plane containing the drum axis. Y

As shown in Figure l, the journal structure 4--4a has an internal passage 14 formed therein for introduction of a heat transfer medium, such as steam. Ports 1S extended radially of the journal interconnect the passage 14 with the interior of the spokes formed by the pairs of plate elements 12. Additional ports 16 through the inner drum wall 7 interconnect the space between the plates 12-12 and the annular chamber at the periphery of the drum. Supply of heat transfer medium to the annular chamber at the periphery of the drum is also provided by a pipe 17 which lies interiorly of the drum and interconnects the passage 14 in the left hand journal structure (when viewed as in Figure 1) with the passage 18 provided in the inner end portion of the projection 5a of the right hand journal. Ports such as shown at 19 extended radially in the right hand journal structure interconnect the passage 18 with the interior of the spokes formed by plate elements 12 at the right hand end; and these spokes are in turn connected with the annular chamber at the periphery of the drum by means of ports 20 through the inner drum wall 7.

By the arrangements of passages and ports just de scribed, the heat transfer medium is delivered Vinto the annular space at the periphery of the drum in regions adjacent both ends thereof, from an inlet passage (14) at one end.

Condensate may be removed from the annular charnber at the periphery of the drum by means of the piping 21 which has its inlet end 22 projecting into the annular chamber at the periphery of the drum. The other end of this piping communicates through port 23 with the passage 24 provided in the journal structure 5-5a at the right hand end of the drum structure.

The arrangement of the plate elements in the hub structures to provide at hollow spokes is of great importance for several reasons. First, since the spokes are of relatively small dimension circumferentially of the journal structure, a substantial number of such spokes may be incorporated in the hub structure and individually welded to the journal. The flat shape of the spokes also provides relatively large inter-spoke spacing for convenient access to the interior of the drum. In addition, the fact that the spokes are broad in a direction paralleling the axis of the drum provides a broad base of interbracing between the inner and outer shells and the journal structure, and this in turn eliminates the necessity of employing a structural interconnection inside the drum between the journal structures at the two ends. interconnecting the passage 14 in the journal at the left with the passage in the journal at the right is advantageously relatively light, serving merely as a conduit for steam ow, rather than as a structural interbrace between the two journals. Such tubing will give under the intluence of thermal expansion and contraction of the inner and outer shell walls. This is also of advantage as compared with an arrangement employing a true structural interconnection between the journals at opposite ends of the drum. With such latter arrangement irregular heating and cooling as between the shell walls on the one hand and the structural interconnection between the journals on the other hand, results in subjection of the hub structures to heavy stresses, for instance at times when the drum is being heated up for operation.

The flanged or ued openings in the pairs of plates 12 and the interconnection thereof, as by the welds 13a serves several important purposes, including a strengthening of the flat areas of the spokes so as adequately to withstand the pressure of the steam owing therethrough. This The tubing 17 illustrated as' arrangement also provides a reduced cross section at certain points in the spokes of the hub structure and thereby relieves or reduces thermal stresses arising at times because of unequal heating of different portions of the system. Interconnection of the pairs of plates 12 also ensures that these pairs of plates act as a unit in shear.

The hub structures as fully described above are of exceptional strength, capable of withstanding the heavy stresses encountered not only as a result of thermal expansion and contraction but also as a result of the relatively great weight of rolls of this kind when considered in relation to the length thereof.

We claim:

1. in a double shell steel drier drum having a journal member and inner and outer shell walls spaced from each other to provide an annular chamber for a heat transfer medium, a hub structure interconnecting the journal member and said walls and being of multipart built-up construction and comprising plate elements some of which lie in planes extended perpendicularly to the drum axis and some in planes extended radially of the drum and welded to each other to define hollow atted spokes having their major cross sectional axes extended lengthwise of the drum, the said spokes interconnecting the journal member and the shell structure, and portage interconnecting the interior of the spokes with said annular chamber to provide for iiow of heat transfer medium therebetween.

2. A construction according to claim l in which the plate elements defining the side faces of the spokes are interconnected intermediate the edges thereof.

3. A construction according to claim 2 in which the interconnection between the plate elements defining the side faces of the spokes comprises a flued aperture in at least one such plate element of each spoke with the free edge thereof connected with the plate element at the opposite side face of the spoke.

4. A construction according to claim 1 in which the drum has a hub structure at each end conforming with that dened in claim l and in which the two hub structures are structurally substantially independent of each other except for the interconnection thereof through the shell structure.

5. ln a drier drum havingk a double wall structure adapted to receive a heat transfer medium and a journal member with a passage therein for a heat transfer medium, a hub interconnecting the wall structure and the journal member and being of multipart built-up construction and comprising pairs of spaced plates interbracing the iournal member and the wall structure and lying substantially in planes containing the drum axis, and additional plate elements interbracing the journal member and the wall structure and lying in planes perpendicular to the drum axis, said additional plate elements being located at the radial edges of the pairs of plates and serving to close the spaces between the plates of said pairs, and the spaces between the plates of said pairs being in communication with the passage in the journal member and serving as a passage for heat transfer medium between the journal passage and said double wall structure.

6. ln a drier drum having a drum wall and a journal, a hub structure interconnecting the drum wall and journal and comprising a pair of plate members lying in planes perpendicular to the drum axis and having portions cut out to define radial spokes extending between the drum wall and journal, and pairs of spaced plate elements lying in substantially radial planes and extending outwardly from the journal adjacent the edges of the spokes, said pairs of spaced plate elements being connected to the spokes and to the drum wall, and said pairs of plate elements having cut out portions intermediate the marginal edges thereof and being interconnected around said cut out portions.

7. In a drier drum having a double wall structure adapted to receive a heat transfer medium and a journal member with a passage therein for a heat transfer medium, a hub interconnecting the wall structure and the journal member and being of multipart built-up construction and comprising pairs of spaced plates interbracing the journal member and the wall structure and lying substantially in planes containing the drum axis, the space between the plates of a pair being in communication with the passage in the journal member and serving as a passage for heatdtrasfer medium between tt1ll1e References Cited in the le of this patent journal passage and said ou e wall structure, and e plates of said pairs having cut out portions intermediate UNITED STATES PATENTS the marginal edges thereof and being flanged or ued Number Name Date around the cut-outs, with the anged portions intercon- 5 171,523 Medberry et al. Dec. 28, 1875 nected. 544,782 Bragg Aug. 20, 1895 2,563,692 Ostertag et al. Aug. 7, 1951 2,651,114 Hornbostel Sept. 8, 1953

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