US3299530A - Papermaking machine - Google Patents

Description

4 Sheets-Sheet l ...w E n N \o l5 IV @J m.

R. M. Elss ETAL.4

PAPERMAKING MACHINE Jan. 24, 1967` Filed March ll, 1965 Jam.v 24, 1967 R. M. E155 ETAL PAPERMAKNG MACHINE Filed March 11, 1965 4 Sheets-Sheet 2 FIG,.2.

Y R. M. Else ETAL PAPERMAKI-NG MACHINE Filed March 11, 1965L 4 Sheets-Sheet 5 Jn 24, 1957 R. M. Elss ETAL 3,299,530

PAPERMAKING MACHINE Filed March l1, 1965 4 Sheets-Sheet L FIG.5. 48

United States Patent @nice staats@ Patented Jan. 24, 1967 3,299,530 PAPERMAKING MACHINE Robert M. Eiss and .loseph B. Webb, Neenah, Wis.` asi signers to Kimberly-Clark Corporation, Neenah, Wis.,

a corporation of Delaware Filed Mar. 11, 1965, Ser. No. 438,837 6 Claims. (Cl. 34 124) The invention relates to steam heated drier drums, which may be used in pape-rmaking machines, for example, and more particularly to condensate drainage devices for such drier drums.

Papermaking machine drying sections generally include a plurality of drier drums, each of which comprises a cylindrical shell, spaced heads extending radially across the shell to close the open ends thereof, carrying means for journlalling the shell, means for introducing steam into the interior of the shell, and means for Withdrawing steam condensate therefrom. The paper web travels serially over these drums in such a drying section. A Yankee drier `drum has substantially the same structural .arrangement as the drier drums in the drying sections just mentioned; however, a Yankee drier drum is ordinarily of substantially greater diameter; and only a single one of these drums is generally used, as in connection with tissue or lightweight webs.

On modern high speed tissue making machines, the machines and the vassociated drier drums run at speeds up to 4,000 to 5,000 feet per minute. Steam condensing on the inner wall of a rotating drier drum in such a machine forms condensate which must be continually removed in order to obtain good heat transfer. The condensate is held against the shell by centrifugal force which presses the fluid out in a thin sheet covering the entire inner wall of the drum. The sheet of paper or tissue being dried on the outer wall of the drum is usually very sensitive to any change in heat transfer through the wall; and, assuming that a condensate removal system causes the sheet of condensate within the drum to be of unequal thickness, the heat transferring characteristics of the drum across its surface are changed, so that the paper or tissue is thereby caused to run wet in streaks or bars according to the pattern created by the condensate removal system.

Available condensate siphons draw off the condensate locally at a number of places within therdrum and may include two or more manifolds extending lengthwise of the drum adjacent its inner surface and having outlet tubes connecting the manifolds with a journal of the drum through which the condensate may discharge. The condens-ate inlets to the manifolds are substantially open with respect to the outlet tubes,iand there vis no substantial pressure drop between the inlets and outlets tubes; and, therefore, the rate at which the condensate is `dnawn off is greater in the areas of the outlet tubes than in areas away some distance from these tubes. The condensate is thus not uniform in thickness on the inside of the drum, and the drying rate of the drum thus is not uniform on the complete drum surface. ln one particular type of -manifold condensate withdrawal system, a pair of manifolds extend lengthwise of the `drier drum adjacent the inne-r drum surface, and each of these manifolds has a plurality of holes drilled into it extending generally tangentially of the inner drum surface. The steam sweeps across the face of the sheet of water condensate into these holes and sweeps water from the inside surface of the drum into these holes and thereby into the associated manifold. Since centrifugal force is effective on the condensate entering the manifolds, it tends to lie in the bottom of each manifold; however, immediately in front of the outlet tubes that connect the manifold with the journal of the drier drum, the steam velocity is high enough to draw up water from the inside surface of the manifold at these points so that the inlet holes in the lower face of the manifold adjacent to the outlet tubes draw condensate more effectively than those located some distance from each side of the outlet tube. This unequal flow through the manifold inlet openings causes an undesirable, unequal temlperature profile across the drier drum.

It is an object of the present invention to provide an improved condensate removal system of the manifold type which is so constructed that there is a substantially equal rate of condensate withdrawal by the manifolds from one end to the other end of the drum.

In brief, we accomplish this object by providing a plurality of longitudinally extending manifolds within a drier drum, each having a plurality of spaced small diameter withdrawal tubes extending into it and terminating in close proximity to the inner surface of the drier drum so that condensate may enter the tubes from the internal drum surface. Each manifold has a smaller number of larger `diameter outlet tubes connecting it with the axle and journal of the drier drum through which condensate may flow, and these larger diameter tubes extend into the manifold beyond the inner ends of the small diameter tubes. A 'pond of water tends to lcollect due to centrifugal force within each manifold on its outermost surface, and the larger diameter tubes draw from the pond of water rather than directly from the small diameter tubes and tend to even out the draw and condensate flow through the small diameter tubes. The small diameter withdrawal tubes remote from the larger diameter outlet tubes are also preferably made shorter than the small diameter tubes closer to the large diameter outlet tubes for further evening of the ow of condensate through the small diameter tubes. This construction in which the small diameter tubes extend radially inwardly farther than the inlet ends of the larger diameter tubes also overcomes condensate flooding at the inner ends of the small diameter tubes which would tend to block condensate flow through the small diameter tubes.

The invention consists of the novel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above-stated objects, and such other objects, as will be apparent from the following description of a preferred form of the invention, illustrated with reference to the accompanying drawings, wherein:

FIG. l is a longitudinal sectional view of a Yankee drier drum incorporating the principles of the invention;

FIG, 2 is a sectional View taken on line 2 2 of FIG. 1;

FIG. 3 is a sectional view on an enlarged scale taken on line 3 3 of FIG. 1;

FIG. 4 is an elevational view taken on line 4 4 of FIG. 3; and

FIG. 5 is a sectional view on an enlarged scale taken on line 5 5 of FIG. 4.

Like characters of reference designate like parts in the several views.

Referring now to the drawings, the illustrated drier drum may be seen to comprise a thin cylindrical outer shell 10 which is rigidly secured Iat its ends to a pair of relatively flat ring-shaped heads 11 and 12 supported by a hollow central axle or shaft 13. The shell 10 is provided at each with an integral bolting flange 14 which is machined to mate with a similar peripheral flange 15 on the adjacent head. The rigid attachment of the shell to each head may be made, as shown, by means of a plurality of bolts 16 inserted from the inside of the shell and drawn up by nuts on the outside of the head. Each of the heads 11 and 12 is provided with a manhole 17 to sprovide access to the interior of the drum for assembly and maintenance.

A short cylindrical section 18 provided at its inner end 3 with a machined bolting flange 19 is formed integrally with each of the heads 11 and 12 and extends inwardly at a radial location and is intermediate the inner and outer edges of the head. A plurality of heavy staying members 20 extend between the heads longitudinally of the drier and are xed with respect to the flanges 19 by means tof flanges 21 formed on the staying members and bolts 22 that extend through the anges 19 and 21. The purpose `of the staying members 20 is to control the bowing of the heads 11 and 12 and to eliminate stress occurring in the shell 10 at or near its connections to the heads. t

The shell 10 and heads 11 and 12 are -of cast construction, and the central shaft 13 is also of cast construction and is formed in two halves 23 and 24. The halves 23 and 24 are provided with flanges 25 and 26, and bolts 27 extend through the flanges to x the halves 23 and 24 together. A separator 28 is formed in the half 24 so as t-o provide two separate compartments 29 and 30 in the axle 13.

The shaft 13 near each end is provided with an enlarged bolting ange 31, and each head 11 and 12 is provided with a flange 32 that meets vwith the flange 31; and the flanges 31 and 32 are xed together by means of bolts 33. The shaft 13 is extended at each end to provide journals 34 for rotatably supporting the drier in suitable bearings, a shaft extension 35 being provided at one end 4of the shaft 13 for mounting `a driving gear or sprocket or the like. The shaft 13 at its end is provided with bores 36 and 37, respectively, in communication with the chambers 29 and 30; and the bores 37 and 36 may be utilized, respectively, for providing steam under pressure into the compartment 30 and for withdrawing the steam condensate from the compartment 29.

A drier drum, substantially as so far described, is disclosed in Patent 3,099,543, issued to Malmstrom et al. on July 30, 1963, and assigned to the same assignee as the present application.

Steam under pressure is supplied to the interior of the drier drum by means of steam supply pipes 38 having rows of steam discharge openings 39 formed therein and extending axially of the drier drum along the shaft 13. The pipes 38 are connected to the compartment 30.

The condensate removal system of the invention comprises a pair of manifolds 40 and 41 positioned oppositely from each other with respect to the shaft 13 and located adjacent the inner surface `of the shell 10. Each of the manifolds 40 and 41 is rectangular in cross section, as shown in FG. 5, and comprises a pair of elongated hollow shells 42 and 43, which are welded together at their edges. Each manifold 40 and 41 is supported from adjacent staying members 20 by means of A-shaped brackets 44. Each of the brackets 44 has one -of its legs bolted to a staying member 20 and carries a U-shaped bar 45 on its uppermost portion which is indented to receive a manifold 40 or 41, and the manifold is welded to the bar 45. Each manifold is supported from the sections 18 by means of brackets 46 which are welded to the manifold adjacent its ends and which are bolted to the sections 18.

A plurality of small diameter tubes 47 extend radially through the outermost wall 43a of ea-ch of the manifolds 40 and 41. The tubes have their outer ends 48 terminating adjacent the inner surface of the shell 10 and have their inner ends 49 terminating well within the associated manifold, preferably at least to the center of the manifold. In the particular embodiment lof the invention illustrated, each of the manifolds 40 and 41 is provided with thirty-two of the small diameter tubes 47 which are located on 2% inch centers.

Each of the manifolds 40 and 41 has four equally spaced, relatively large diameter condensate withdrawal tubes 50 extending into it through its innermost wall 42a. The outer end 51 of each of the tubes 50 is located adjacent to the outer Wall 43a of the associated manifolds.

The tubes 50 of each of the headers are connected by means of branch pipes 52 and 53 with a central header 54 which is connected with the compartment 29 in the shaft 13. The headers 54 are located equi-distantly from the heads 11 and 12 except that the headers are angled to the left as seen in FIG. 1, toward the separator 28, to avoid the flanges 25 and 26 in passing through the shaft 13 into the compartment 29.

The tubes 47 are preferably of different lengths, the tubes 47 located closer to the withdrawal tubes 5t) being longer than the tubes remote from the Withdrawal tubes 50, in order that there shall be more restriction to the flow `of lcondensate and steam through the small tubes 47 located closer to the Withdrawal tubes 50 than through the other tubes 47. Insofar as length is concerned, the tubes 47 in the illustrated embodiment may be designated as the different length tubes 47a, 47b, 47C, and 47d. The tubes 47d are longer than the tubes 47C, which in turn are longer than the tubes 47b, and the tubes 4717 are longer than the tubes 47a. Between each group of tubes there may, for example, be a difference of length of 1/2 inch. The tubes 47a in the particular illustrated embodiment terminate substantially midway between the manifold Walls 42a and 43a, and the tubes 47b, 47C, and 47d terminate respectively at additional distances of 1/2 inch from the louter wall 43a of the manifold. The withdrawal tubes 50 extend radially outwardly substantially closer to the outermost wall 43 than the inner ends of the shortest tubes 47a, the tubes 50 having their ends 51 located an inch, for example, from the ywall 43a of the manifold while the short tubes 47a terminate 3 inches, for example, from the outer wall 43a.

Although, as will be obvious, the internal diameter and length of the tubes 47 lmay be varied; in one particular embodiment -of the invention, the bores of the tubes 47 were .307 inch in diameter and the tubes varied in length from 5% inches t-o 6% inches. The tube ends 48 may be located, for example, from 1/s inch to inch from the internal surface of the shell 10, and a good working distance in actual practice between the tube ends 48 and the internal shell surface has been found to be about /l@ inch, The large diameter condensate withdrawal tribes 50 had-an internal diameter `of one inch in this embodiment.

In operation, moist paper web is directed onto the outer surface -of the shell 10, `and the drum may be rotated by means of the sprocket or other driving mechanism on the extension 35 at a high speed, such as 4,000 to 5,000 feet per minute, for example. The web is dried as the drum rotates, and the web maybe creped ofic the outer surface of the drum by means of a suitable creping blade (not shown).

Steam under pressure is supplied to the compartment 30 through the bore 37, Vand the steam is directed into the internal compartment of the drum through the supply pipes 38 and the discharge openings 39 in the pipes 38. The steam heats the drier drum, and, in doing so, it condenses into Water; `and the water condensate rims the internal surface of the shell 10 completely around the shell, to a depth of 1A inch, for example. The `condensate removal system, including the manifolds 40 and 41 and the small diameter tubes 47, remove this condensate.

To maintain the surface temperature and the drying effect of fthe shell 10 as uniform as possible, the depth of the water condensate is maintained as uniform as possible about the internal surface of the shell 10. Steam within the drier drum rushes to the ends 48 of the tubes 47 located close to the internal drum surface, since the pressure within the tubes 47 and in the connected manifolds 40 and 41 and compartment 29 is lower than the pressure of the steam within the drum. The steam, in entering the ends 48 of :the small diameter tubes 47 sweeps across the inner turface of the drier drum, and atomizes the condensate existing on the inner drum surface. Thus, a steam-water mixture passes radially inwardly through the bores of the tubes 47 into the manifolds 40 and 41. In order that such atomization occurs, the velocity of the steam entering the bores of the small diameter tubes 47 is high, and the velocity of the steamwater mixture within the tubes 47'may be, for example, about 110 feet per second. The small diameters of the bores Within the tubes 47 provide this high velocity; and, due to the high Velocity, the pressure within the bores of the tubes 47 is reduced from'the pressure within the drum by about 5 pounds' per square inch. i

' The steam-water' mixture flowing radially inwardly through the tubes 47, of course, is subject to centrifugal force due to the high velocity of rotation of the drier drum; however, since there is atomization in the vicinity of the ends 48 of :the tubes 47, the pressure of the steam within the drier drum is effective to move the water-steam mixture inwardly against the centrifugal force. It will -be understood that if such atomization should not occur, it would be more difficult to move theundiluted condensate inwardly against centrifugal force due to its increased densityl .n

There is some condensation taking 'place within the manifolds 40 and 41, and the water-steam mixture in passing through the tubes 47 also tends to separate into water and steam components; however, since the tube ends 51 are located quite close to the outer walls 43a ofthe manifolds 40 and 41, substantially the same atomizing action takes place on these walls as takes place at the ends48 of the tubes 47. Due to centrifugal force, water'in the manifolds 40 and 41 tends to pond on the outer surfaceA 43a, and the steam in sweeping across the ends 51 of the tubes 50 tends to atomize any water on the outer walls 43a of the manifolds 40 and 41 and draws it along with the steam as a water-steam mixture radially through the tubes 50 and into the compartment 29 of the shaft 13 by means of the pipes 52, 53 and 54. The velocity of the steam-water mixture through the tubes 50 may be, for example, 80 to 90 feet p er second.

The compartment 29 is connected through the bore 36 within a suitable steam condensate separator (not shown), and the pressure of steam within the compartment 29 i-s controlled by any suitable valve means (not shown). It will be understood, of course, that the steam pressure drops, in general, from the tube ends 48 through the manifolds 40 and 41 and through the pipes 53 and 54 and through the compartment 29, as the steam-water mixture flows to the separator. The steam pressure, for example, may drop from about 125 pounds per square inch within the drier drum to 110 pounds per square inch within the bore 36.

Due to the atomization of the condensate on the outer walls 43a of the manifolds 40 and 41, the walls 43a are swept relatively clean of water so that there is no flooding of the manifolds, and hence no impedance by flooding to any flow of a Water-steam mixture through the small diameter tubes 47. The tubes 47 cannot be blocked particularly due to the fact that the inner ends 49 of the tubes are located closed to the center of rotation of the shell than are the ends 51 of the tubes 50, and hence the inner ends 49 of the tubes 47 protrude clear of any water ponded on the surfaces 43a.

It will be observed that the steam-condensate mixture travels from the ends 48 of the tubes 47 to the compartment 29 in two -stages in each of which there is a sweeping action of the steam across la surface atomizing the water condensate; and the structure providing this twostage action has been found to provide more uniformity of condensate removal lengthwise of the drier drum and lengthwise of the manifolds 40 and 41 than if there were a simple direct connection between each of the small diameter tubes 47 and the compartment 29. If there are any water ponds on the surfaces 43a caused by centrifugal forces, the large diameter tubes 50 tend to be immersed in these water ponds; and the atomizing action at the ends 51`of the tubes 50 functions to provide substantially the same reduced pressure within the manifolds 40 and 41 from one end to the other end of each manifold. Therefore, all of the small diameter tubes 47 have nearly the same pressure effective at their inner ends 49 so that condensate ow in all of the tubes 47 is fairly uniform. Y

In order to take care of the slight variations in pressure that exist within the manifolds 40 and 41 adjacent and remote from the outlet tubes 50, the tubes 47d located close to the tubes 50 have been made longer than the tubes 47a remotely located with respect to the tubes 5ft,V and the intermediate :tubes 47b and 47C are intermediate in length with respect to the tubes 47a and 47d. The impedance to flow of the water-steam mixture through the tubes 47, of course, increases with :the length of the tubes 47; and, `since there is a slightly greater tendency to draw water-steam mixture out of the tubes 47 located closer toy the outlet tubes 50, the tubes 47 remotely located with respect to the outlet tubes 50 have been made shorter so as to equalize the flow of water condensate mixture through the various tubes 47. Also, in equalizing the flow, the headers 54'have been located centrally within the drier drum, except for the slanting portionsof the headers 54 leading to one side of the anges 25 and 26.

The above-described condensate removal system advantageously is non-flooding with respect to the small diameter tubes 47 due to the fact that the large diameter tubes 50 extend in close proximity to the surface 43a of the manifolds and the tubes 47 extend inwardly 'beyond the ends 51 of the tubes 50. The two-stage action of the condensate withdrawal system also assures quite substantial uniformity of condensate withdrawal from one end to the other end of each of the manifolds 40 and 41,

this two-stage action constituting the atomizing effect of the small diameter tubes 47 on the internal surface of the shell 10 and the atomizing effect of the ends 51 of the large diameter tubes 50 with respect to the adjacent internal surfaces 43a of the manifolds 40 and 41. In order to correct any minor discrepancies of flow through the tubes 47,'the tubes47 are also preferably made greater in length adjacent the outlet 1tubes 50, as described.

We wish it to be understood that the invention is not to be limited to the specific constructions, arrangements and devices shown and described, except only insofar as the claims may be so limited, as it will be understood to those skilled in the art that changes may be made without departing from the principles of the invention. In particular, we would like to have it understood that, although the tubes 47 are shown exactly radially, these tubes could, if desired, be set at an angle with respect to radii of the drier drum and also with respect to the tubes 50. Also, it will be understood that, although we have disclosed only two manifolds 40 and 41, additional similar manifolds may be added to the construction` What is claimed is:

1. A hollow dr-ier drum having journals for rotatably mounting the drum, a steam supply connection for didecting steam into the drum, `a manifold in said drum and lying adjacent to the inner surface of the drum, a plurality of water condensate removal tubes extending into and carried by said manifold and terminating closely adjacent to the inner drum surface, and a water condensate removal pipe connected to a condensate removal connection and extending outwardly into said manifold, said pipe extending farther outwardly radially than the inner ends of said tubes so as to prevent blockage by condensate of said tubes.

2. A hollow drier drum having journals for rotatably mounting the drum, a steam supply connection for direct-ing steam into the drum, a plurality of manifolds in said drum lying adjacent to the inner surface of the drum and equi-distantly spaced from each other, a plurality of water condensate removal tubes extending generally radially into and carried by each of said manifolds and terminating on their outer ends closely adjacent to the inner drum surface, and a plurality of condensate removal pipes connected to a condensate removal connection and extending generally radially into each of said manifolds, said pipes having their outer ends terminating closer to the outermost wall of said manifolds than the inner ends of said tubes so as to prevent blockage of condensate of said tubes.

3. A drier drum having journals for rotatably mounting the drum, a steam supply connection for directing steam into the drum, .a plurality of manifolds in said drum and extending generally axially of the drum adjacent to the inner drum surface and equi-distantly spaced from each other, a plurality of water condensate removal tubes extending generally radially into and carried by each of said manifolds and terminating on their outer ends closely adjacent to the inner drum surface, and a plurality of water condensate removal pipes connected to a condensate removal connection .and extending generally radially into each of said manifolds and equi-distantly spaced along the length of the manifold, the inner ends of said tubes extending further inwardly radially of the drum than the outer ends of said pipes and certain ones of the tubes .adjacent to said pipes in each of said manifolds being longer than other ones of said tubes which are more remote from said pipes for equalizing the flow of condensate through said tubes and into said manifolds.

4. A hollow drier drum having journals for rotatably mounting the drum, a steam supply outlet in said drum 4and connected to one of said journals for directing steam into the drum, a plurality of manifolds in said drum and extending generally axially of the drum adjacent to the inner drum surface and equi-distantly spaced about the drum, a plurality of water condensate removal tubes of relatively small diameter extending radially into and carried by each of said manifolds and terminating closely adjacent to the -inner drum surface, .a plurality of water condensate removal pipes extending radially into each of said manifolds and having a water removal connection with the other of said journals, said pipes being substantially less in number than the number of said tubes and being of larger internal diameter than said tubes and being equally spaced along each of said manifolds, said pipes terminating closely adjacent to the outermost surfaces of said manifolds and said tubes terminating within the manifolds farther from said outermost manifold surfaces than said pipes.

5. A hollow drier drum having journals for rotatably mounting the drum, a steam supply connection for directing steam into the drum, a manifold in said drum and lying adjacent to the inner surface of the drum, a plurality of water condensate removal tubes extending into and carried by said manifold and terminating closely adjacent to the inner drum surface, a condensate removal connection, and water condensate removal piping connected to said condensate removal connection and to said manifold and terminating farther outwardly in the manifold than the inne-r ends of said tubes so as to prevent blockage by condensate of said tubes.

6. A hollow drier drum having .a hollow central axle with end journals for rotatably mounting the drum, a steam supply connection for directing steam into the drum, a plurality of manifolds in said drum and equally spaced about the drum and lying adjacent to the inner surface of the drum, a plurality of water condensate removal tubes extending into and carried by each of said manifolds and terminating closely adjacent to the inner drum surface, said .axle being vented through one of said journals so as to provide a Water condensate removal connection, and water condensate removal piping connected to said axle and also connected to each of said manifolds at a place in each of said manifolds located farther outwardly than the inner ends of said tubes so as to prevent blockage of condensate of said tubes.

References Cited by the Examiner UNITED STATES PATENTS 3,169,050 2/1965 Kroon 34-l24 DONLEY I. STOCKING, Primary Examiner. A. D. HERRMANN, Assistant Examiner.

Claims (1)

1. A HOLLOW DRIER DRUM HAVING JOURNALS FOR ROTATABLY MOUNTING THE DRUM, A STEAM SUPPLY CONNECTION FOR DIDECTING STEAM INTO THE DRUM, A MANIFOLD IN SAID DRUM AND LYING ADJACENT TO THE INNER SURFACE OF THE DRUM, A PLURALITY OF WATER CONDENSATE REMOVAL TUBES EXTENDING INTO AND CARRIED BY SAID MANIFOLD AND TERMINATING CLOSELY ADJACENT TO THE INNER DRUM SURFACE, AND A WATER CONDENSATE REMOVAL PIPE CONNECTED TO A CONDENSATE REMOVAL CONNECTION AND EXTENDING OUTWARDLY INTO SAID MANIFOLD, SAID PIPE EXTENDING FARTHER OUTWARDLY RADIALLY THAN THE

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