US2542287A

US2542287A - Drying drum

Info

Publication number: US2542287A
Application number: US627032A
Authority: US
Inventors: Herman E Neubauer
Original assignee: Blaw Knox Co
Current assignee: Blaw Knox Co
Priority date: 1945-11-06
Filing date: 1945-11-06
Publication date: 1951-02-20
Anticipated expiration: 1968-02-20

Description

Feb. 20, 1951 H. E. NEUBAUER 2,542,287

DRYING DRUM Filed Nov. 6, 1945 2 Sheets-Sheet 1 INVENTOR.

M a %m ATTOFNZ'YS Feb..20, 1951 H. E. NEUBAUER 2,542,287

DRYING DRUM Filed Nov. 6, 1945 2 Sheets-Sheet 2 ATTORNEYS 4 BY IIIII II ing a revolution; and with which removal of the condensed steam will not be materially interferred with.

Other objects and advantages will be apparent from the following description of an embodiment of the invention, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawings:

Fig. 1 is a longitudinal, sectional elevation through a dryer drum constructed in accordance with this invention and illustrating an embodiment thereof;

Fig. 2 is the longitudinal, sectional elevation through the drum alone, but with parts of slightly different proportions than in Fig. 1; and

Fig. 3 is a transverse, sectional elevation through the same, the section being taken approximately along the line 33 of Fig. 2.

In the illustrated embodiment of the invention and referring particularly to Fig. l, the improved dryer drum includes a generally cylindrical wall I having at its ends inturned radial flanges 2. A closure 3 is secured to one end of r the wall I, and extends across the opening at that end of the wall. so as to overlap with the flange 2 and tightly close that end of the wall. This closure 3 may be detachably secured to the flange 2 in any suitable manner, such as by screws I which pass through the periphery of the clo ure 3 into the flange 2. At the opposite end of the cylindrical wall I is a somewhat similar closure 5 which is similarly secured to the other flan e 2 in the ame manner, such as by screws 4. Thus the cylindrical wall I is closed at both ends by the closures 3 and 5 to form a closed, hollow drum that is generally cylindrical in shape.

The closures 3 and 5 have bearing trunnions or bosses 6 extending from the ends thereof so that the drum may be rotatably mounted in suitable bearings, not shown.

One of these trunnions 6, such as the one on the closure 5, is tubular and open at both ends so as to provide an axial pa sage I opening into the chamber 8 of the drum formed by the wall I and closures 3 and 5. The trunnion 6 on closure 3 is closed at its outer end. A tube 9 is disposed in the passage I and is held against rotation relatively to the adiacent trunnion through which it passes. A stufiing box or gland It is provided on the outer end of the bearing a of closure 5 around the tube 9 so as to close the passage I except for that through the tube 9. This tube 9 extends into the chamber 8 and there terminates in an open end II. The outer end of the tube 9 is closed by a disk I2, but adjacent the closed end the tube is provided with a laterally extending boss I3 into which a pipe from a source of steam may be connected. Within the tube 8 is a pipe I having an external diameter smaller than the internal diameter of the tube 9, and extending from outwardly beyond the stuffing box I!) along the tube 9 into the chamber 8 and there joined to a detachable, but downwardly extending pipe I5, which, at its lower end, extends into close proximity to the inner periphery of the wall I. This lower end of the pipe I5 is open, and the outer end of the pipe I4 is suitably connected to a steam trap or other source of suction, or to a siphon device so that a suction will be created at the lower end of the pipe I5 within the chamber 8 of the drum to remove from the drum the steam condensing therein and collecting as a pool in the bottom part of the drum.

The tube 9 and pipe I4 are held against rotation so that the pipe IE will always extend to the bottom of the drum while the drum is rotating. Suitable means, not shown, is mounted on the hearing B'of closure 5 to turn the drum at the desired rate. These drums may be used singly or.

in groups.

The wall I of the drum is provided with a plurality of internal, endless, annular rings or ribs I6 which are formed integrally with, or are welded to, the inner peripheral surface of the wall i and extend radially but only partially across the chamber 8. These ribs I8 are disposed side by side but spaced apart at intervals along the length of the drum, and are peripherally continuous along the wall I.

The condensed steam will normally collect in a poolalong the bottom part of the drum, and when the drum is rotating it will be spread as a film along the surface of the drum in a peripheral direction to an extent depending upon the speed of rotation and the amount of liquid accumulating in the bottom of the drum. The condensed liquid will flow towards the portion of the drum where it is removed through the pipe i5. In order to facilitate the movement toward the pipe I5 of the liquid collecting in the bottom part of the drum, and keep the depth of the pool to a minimum, the ribs I5 are each preferably provided with one or more ports or apertures I'a" disposed in close proximity to the inner periphery of the wall I. The condensed liquid may thus pass through these ports or apertures to pipe I5 for removal, which reduces the extent to which the film of liquid spreads out alongthe inner periphery of the drum due to the rotation of thedrum. In other words the ports or apertures I'd make it possible to keep the depth of the pool of condensate in the bottom part of the drum to a minimum. There are preferably a plurality of such ports or apertures IT in each rib, spaced apart in a direction peripherally of the drum, as shown clearly in Fig. 3, so that the condensate in the bottom part of the drum will have the desired freedom of movement toward the inlet end of the pipe I 5 while the drum is rotating. Only one suction pipe is required, and yet the pool of condensate in the bottom part of the drum may be ke t to a minimum depth.

Each of the ribs preferably also terminates along its inner edge in a lateral flange I8, preferably a double flange extending in both directions from the inner periphery of the rib, generally parallel to the axis of rotation of the drum. These flanges I8 with the rib provide a very rigid stiffening reinforcement for the wall I of the drum, and substantial face area in contact with the steam, and when the double flange is used, such a reinforcement is T-shaped in cross section with the head of the T forming the inner periphery of the rib.

The T-shaped cross section, together with the portion of the drum wall to which it is attached, corresponds to the cross section of an I-beam which is recognized as a structure having maximum resistance to deflection and distortion with a minimum of weight, and of depth of the rib. As an illustration of the value of the T-shaped rib with the head of the T spaced from the drum surface, a comparison of the resistance to deflection of a drum with stiffening ribs of difierent types may be easily made by tests upon a hoop of the same width or depth as the rib or T section, undera load applied to the hoop at two opposite points. Under such tests it can be estab lished that the T-shaped reinforcing rib will inamazon 5.? crease the resistance 'to'dis't'ortion or stifiness oi the hoopby about twelve. times thatof. a hoop with no rib, whereas a plain rib of the same width and depth, but without the T flange on its inner periphery; will increase the strength of the hoop by about fountimes that of a hoop with no rib.

In Fig. 2 the drum is similar. tor that shown? in Fig. 1, but is of full lengthhto show moreseitectively the 1 plurality of ribs...- spaced along. .--the same. Similar parts are given similar reference characters.

Fig; sillustrates more effectively than inFig. 1., the spacing. arrangement of the apertureswll along the rib..

It will be observed thatthe reinforcing ribs extend into the chamber of the: drum :wh'eretheir massis in goodv thermal relation:with'zthezsteami which "is usually at: a constant: temperature,

which facilitates transfer of heat=from the steam" to the peripheral wall by conduction. Consequently heat loss by conduction to the shell is reduced to a minimum, and the stiifening rib itself is not subject to thermal deformation with the shell which is necessarily exposed to temperature variations or differentials. Thus the stifiening rings or ribs are maintained at an approximatel constant temperature by a substantially total immersion in the body of steam or other heating fluid.

In double drum dryers as heretofore made without the stiffening ribs. the distortion and irregularity in the surface of the drum became progressively worse with the passing of time, and it is impractical to make the peripheral wall of the drum sufiiciently thick to avoid such distortion. Drums having the internal, annular endless stiffening ribs in accordance with this invention, after operation for a substantial period of time in which appreciable distortion would appear if the drums were not stiifened with these ribs, have been found to have no material distort on and no material decrease in their drying capacity.

Standard drums of the same wall thickness without the reinforcing ribs were a continuous source of trouble, and distortion therein was such that a variation in clearance between high and low spots on the drums in much less than a year, would often amount to from .010 to .050 inch. The capacity of such unstiifened drums was reduced as much as 50% because the drums then had to be forced closely together to reduce to a minimum the clearance at the low spots. The drum speed had to be reduced to prevent wet spots on the drums and to remove the moisture from the heavier parts of the film. On the high spots, there would either be no film at all, or a very thin film, and when heat sensitive products were dried, there was considerable overdrying, loss of quality of the product, and sometimes scorching. In order to maintain production when using drums without stiffening ribs and operating under critical conditions, it was necessary to resurface the outside surfaces of the drums at frequent intervals.

These difiiculties appear to be fully overcome when the drums are provided with the internal stiifening ribs in accordance wtih this invention, so thatoperation of the improved stiffened drums even under critical conditions for relatively long periods of time, without resurfacing, appears to be possible. When the improved drums are used to dry a traveling web, of paper as in a paper mill, it is important that there be a rapid transfer of heatrfrcmzthaisteam admittedatorthe drumzto the. outer peripheral drumrsurface'sand'. the' ribsi act asnvanes. which provide somewhat betterfheat' transfer from: the. steam to the wall contactwitlr'the': moving web, as: well as: reducing or' eliminatingdistortion of the; drum such as==would1re+ quire resurfacing Ofxthfdl'lllfl surface;

It :will he: understood that various changes tin the details... materials andiarrangem'entsief parts; whichlhave'been herein described and'illlustrated in order 1' t I explain the. nature? of theiiinvention; mayzbe. madebythose skilled in i the art within the principle andiscop'eiofthe invention, as"ex-= prssediinithe appended claims:

I claim:

1. Inia dryer iofi thewtypietin which steam "is ad"- mitted :to the interior of a hollow, rotatable, closed: drum to heat the exterior drying surface thereot-andfrom whichcondensatioin is removed by a pipe extending intcthe chamber of the drum and-'zdownwardly therein into close proximity to the bottom portion of the periphery of the drum, that improvement which comprises an annular T-shaped rib within and intermediate the ends of the drum, having the base and of the leg of the T rigidly attached to the inner periphery of the drum and extending radially of the drum, with the head of the T forming the inner periphery of the rib, the leg of the T being apertured from face to face, and the head of the T being radially nearer the axis of rotation of the drum than the opening of said pipe within said drum, the space at each side of the rib being unobstructed, whereby When the drum is internally heated by steam and the condensed steam is removed through said pipe, the flange formed by the head of the T will b entirely in an atmosphere of steam so as to remain at a relatively constant temperature and will resist substantial distortion of the peripheral wall of the drum.

2. An axially elongated dryer element, which comprises a hollow drum having a cylindrical peripheral shell and end walls closing and supporting the shell, means mounting the drum for rotation about the longitudinal axis of said shell, means for delivering steam to the interior of the drum, a non-rotatable pipe entering the drum through an end wall thereof and along said axis, and within the drum having an open inlet end close to the bottom of the drum, and a plurality of annular, T-shaped ribs on the inner periphery of said shell, spaced apart lengthwise of the drum, each rib having its leg apertured from face to face and rigidly attached at its base to, and peripherally continuous with, the inner peripheral surface of said shell, with the head of the T forming the inner periphery of the rib, extending in a direction lengthwise of the shell, and disposed nearer the axis of rotation of the drum than said open end of said pipe, the space between the ribs and between the ribs and end walls being unobstructed, whereby when the drum is internally heated by steam and the condensed steam is removed through said pipe, the flange formed by the head of the T will be entirely in an atmosphere of steam so as to rem'iain at a relativel constant temperature and. will resist substantial distortion of the peripheral wall of the drum.

3. An axially elongated dryer element, which comprises a hollow drum having a cylindrical peripheral shell and end walls closing and supporting the shell, means mounting the drum for rotation about the longitudinal axis of said shell, means for delivering steam to the interior of the drum, a non-rotatable pipe entering the drum through an end wall thereof and along said axis, and within the drum having an open inlet end close to the bottom of the drum, and an annular rib disposedwithin and intermediate of the ends of the interior of the drum, rigidly connected to the inner circumferential Wall of the shell, and extending therefrom towards the axis of rotation of the drum; the rib being apertured from face to face at a plurality of intervals along said shell and terminating at its inner periphery in a "lateral flange that extends parallel to and is concentric with the axis of rotation of the drum, the flange being nearer said axis of rotation than said inlet opening of said pipe whereby when the drum is internally heated by steam and the condensed steam is continuously removed through said pipe, said flange of the rib will be subject to a substantially uniform temperature and will resist substantial deformation of the shell.

HERMAN E. NEUBAUER.

REFERENCES CITED The following references are of record in the file of this patent: V

UNITED STATES PATENTS Number Name Date 134,786 Collier Jan. 14, 1873 666,477 Hunting Jan. 22, 1901 700,776 Hunting V May 27, 1902 1,116,196 Zierden Nov. 3, 1914 4 FOREIGN PATENTS Number Country Date 160,380 Great Britain Mar. 24; 1921 OTHER REFERENCES Pocket Companion for Engineers, Architects and Builders, 19th Edition, published January 1, 1917 by Carnegie Steel Company. Copy available in Division 49.