US3077675A

US3077675A - Paper drying machine

Info

Publication number: US3077675A
Application number: US860914A
Authority: US
Inventors: William A Dickens
Original assignee: KIMBERLY CIARK CORP
Current assignee: KIMBERLY CIARK CORP; KIMBERLY-CIARK Corp
Priority date: 1959-12-21
Filing date: 1959-12-21
Publication date: 1963-02-19
Anticipated expiration: 1980-02-19

Description

Feb. 19, 1963 w. A. DICKENS PAPER DRYING MACHINE 6 Sheets-Sheet 1 Filed D60. 21, 1959 Feb. 19, 1963 w. A. DICKENS PAPER DRYING MACHINE Filed Dec. 21, 1959 6 Sheets$heet 2 Feb. 19, 1963 w. A. DICKENS PAPER DRYING MACHINE 6 Sheets-Sheet 3 Filed Dec. 21, 1959 \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\&\\\\\\\\\\\\\\\\\ Feb. 19, 1963 w. A. DICKENS PAPER DRYING MACHINE s Sheets-Sheet 4 Filed Dec. 21, 1959 W! NEW NIH 1963 w. A. DICKENS 3,077,675

PAPER DRYING MACHINE Fiied Dec. 21, 1959 6 Sheets-Sheet 5 Feb. 19, 1963 w. A. DICKENS 3,077,675

PAPER DRYING MACHINE Filed Dec. 21, 1959 e Sheets-Sheet s United States Patent ()fiice 7 3,077,675 Patented Feb. 19, 1963 3,077,675 PAPER DRYING MACHINE William A. Dickens, Neenah, Wis, assignor to Kimberly- (Iiark Corporation, Neenah, Wis, a corporation of Delaware Filed Dec. 21, 1959, Ser. No. 860,914 2 Claims. (Ci. 34-122) This invention relates to papermaking machines and more particularly to rolls of such machines which have air applied to them for either cooling or heating the rolls. Such a roll may be the large cylinder or Yankee drier drum of a paper machine on which the moist paper is pressed for drying and glazing.

Air is conventionally applied to paper web on a Yankee drier drum by means of a hood located over the drier drum. A plurality of rows of round cross section pipes may be arranged around the periphery of the drum which may vary from 8 to 12 feet in diameter. The pipes are each provided with a series of nozzles directing air from the interior of the pipe on to the periphery of the drum, and the pipes are spaced apart just sufliciently to allow for the expended air to find its way between adjacent nozzles and pipes.

A more uniform application of air to the drum may be obtained using a plurality of ducts or plenum chambers within the hood disposed about the drier drum and extending parallel to the axis of the drum. Each of these ducts has a plurality of apertures or nozzles extending through the wall of the duct facing the surface of the drum, and the apertures or nozzles are arranged in a pattern so that air is substantially uniformly applied on the surface of the drum beneath the duct.

The ducts are generally between 4 to 20 inches wide and have about 2 or 3 inches spacing between them. The spacing is provided so that any wedding or paper accumulating on the drier drum or on the surfaces of the ducts facing the drier drum may be removed by drawing the wadding or paper through the spaces between the ducts.

The provision of such spacing between the ducts, however, has caused the application of air to the surface of the drum to be non-uniform throughout the part of the drum subtended by the ducts due to the fact that there has been no provision for directing air from any of the ducts on to the surfaces of the drum opposite the spaces between the ducts.

It is an object of the present invention to provide an improved apparatus for directing air on to a drum substantially uniformly throughout the part of the drum subtended by the air application apparatus. In particular, it is an object of the invention to provide diagonally extending apertures or diagonally extending nozzles adjacent the edges of the ducts above mentioned for directing air on the surfaces of the drum opposite the spaces between the ducts for achieving this uniformity of air application.

' 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 preferred forms of the invention, illustrated with reference to the accompanying drawings wherein:

FIG. 1 is a side view of a Yankee drier with which a drier hood utilizing the principles of the invention may be utilized;

FIG. 2 is a transverse sectional view of the hood;

FIG. 3 is a longitudinal sectional view of the hood;

FIG. 4 is a fragmentary view similar to FIG. 3, on an enlarged scale, showing a plurality of plenum chambers in the hood;

FIG. 5 is a fragmentary sectional view similar to FIG. 4 on a still further enlarged scale;

FIG. 6 is a sectional view of a nozzle with which the plenum chambers are each equipped;

FIG. 7 is a plan view of a plenum chamber showing the spacing and distribution of the nozzles in the plenum chamber;

FIG. 8 is a schematic elevational view of a drier hood with a plurality of plenum chambers of modified form;

FIG. 9 is a plan view of the modified plenum chambers showing the spacing and distribution of nozzles therein;

FIG. 10 is a fragmentary view of a face of a plenum chamber provided with orifices in lieu of nozzles;

FIG. 11 is a perspective view of a breaker stack provided with a cooling system embodying the principles of the invention;

FIG. 12 is a transverse sectional view of the breaker stack; and

FIG. 13 is a schematic showing of an orifice and the flow of fluid therethrough.

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

Referring now to the drawings and particularly to FIG. 1 thereof, the illustrated machine comprises the usual drum or cylinder 10 mounted for rotation on the frame 11 and provided with the usual pressure roll 12. The paper web to be dried by the roll 10 is carried by a felt Web 13 which travels around felt rolls 14. The roll 12 is rotatably mounted in brackets 15 each attached to an arm 16. Each arm 16 is pivoted at 17 to the frame 11, and the pressure roll 12 is forced against the surface of the drum 10 by a ram 18 which bears against each arm 16.

The dried paper web is removed from the surface of the drum it by a creping doctor which includes a doctor blade 19 movably secured within a blade holder 20. The ends of the holder are provided with shafts 21 which are rotatably mounted within guide blocks 22. The blocks 22 in turn are each slidably mounted within a slide assembly 23 attached to pivot frame 24 pivotally carried by frame 11. Through the slide arrangement provided by the slide blocks 22 and slide assembly 23, the vertical position of the doctor blade I? can be varied, as desired, to obtain the best creping angle.

The doctor blade holder 20 and the blade 19 are pivoted by a toggle mechanism 25 which is attached through a lever arm 26 to one of the shafts 21. In addition, a spring loading mechanism 27 is connected through the toggle mechanism 25 to provide a resilient contact for the doctor blade against the surface of the drum 10.

A hood 28 is disposed about the drum 10 (see FIGS. 2 and 3). A pair of

semi-annular headers

29 and 30 are provided within the hood 28 and are mounted on the frame 111, being positioned adjacent opposite sides of the drum It). The

headers

29 and 30 are connected respectively by supply ducts 31 and 32 to the outlet 33 of an air fan or blower 34 which is of large capacity and may be supported on a platform provided on the frame 11 or elsewhere. Each

header

29 and 30 extends around at least /2 of the drum 1t) and diminishes progressively in cross section away from the fan.

A plurality of ducts or plenum chambers 35 each having

sides

36 and 37 and an inner wall 38 extends between the headers 29 and 30 (see FIGS. 2, 4 and 5). These ducts 35 extend parallel with the longitudinal axis of the drum 10 and are equally spaced apart. The ducts in an actual embodiment may, for example, be 5 or 6 inches wide and have spaces of about 2 inches between them. The actual drier drum in such a case may be expected, for

example, to have a radius of about 5 feet.

which are equally spaced from each other lengthwise of the duct as illustrated in FIG. 7. In a particular embodiment of the invention, each of the nozzles were spaced 012; inch from the nearest nozzle lengthwise of the duct, and the nozzles were spaced 1-.'2 inch from each other crosswise of the duct, with the exception of the

nozzles

39c and 39 Adjacent nozzles-39a are then spaced about 1.6 inch apart, and the same spacing exists for adjacent nozzles 3%, 39d, 39'e, 39gand-39h;

All of the nozzles extend perpendicularly through the wall 38. The nozzles-39c and- 39f are respectively carried by andextend through

edge portions

38a and 38b of. the wall 38-which extend at anangle A with respect to the mainportion of the wall 38 (see FIG. 5). The 1102-

zles

39c and 39 are thus located adjacent the sides of each" of the ducts 35 and extend diagonally with respect to the other nozzles 39 so as to discharge air into,the adjacent space between two-ofthe ducts 35.

Each of the nozzles 39 comprises a tubular portion; 40; (see FIG. 6.) which extends-through the wall 38 and which terminates substantially at the surface. of thewall adja cent the surfaceiofthe drum, Thenozzles comprise also an outwardly flared portion 41 located within the duct 35- Itwill benotedthat the hood 28 encloses; all of the ducts. 35 and that portion of the? drumover which the ducts.v 35 lie. The hood is. spaced apart from the drum-surface and'ducts 35 to,- provide, collecting space 42 for exhaust or spent air blown against the paper W- from the ducts 35 and which passes outwardly to the space 42 between the ducts 35. An exhaust duct 43 is provided in the hood 28- and incommunication with thespace 42. The hood.28'has a'recirculating air duct 44 connected to and communicatingwith the space 42; The duct. 44 is. connected directlyto-make up air duct 45 that supplies. the fan 34, so that theair supplied to the ducts.-

through theiheater 46 wherein itis thoroughly heated and is blown from the fan 34through outlet 33 into ducts-31 and 32, passing therefrom'through; headers Hand 30 which distributeittotheducts 35. The heated air then flows through the nozzles 39 on to the adjacent surface of the drier drum 10. The

nozzles

39a,39b, 39d, 3 9e, 39g and 3% extending perpendicularly through the center partofeach duct wall 38, which is placedto be perpendicular at its center to'a radial line passing through the center: of the drum 10,,direct air normally on the surface of the drum 10; and the nozzlesv39c and 39); extending sidewardly with respect to the'center part of the wall; 38, direct air on to the-outersurface-of the drum 10:: opposite thespaces. between the ducts 35, so as-to-blanket thexsurface of the drum 10 with heated airsubstantiallyuni formly from one end of the hood 28-tothe other, from. its entrance end-to itsexitendfor the web W.

It will bev noted from FIG: 5 that the center lines of the, nozzles 39a, 3%, 39d, 3%, 39g and 39h intersect thesurface of the drier drum 10 substantia1ly1.2 inches. apart. The center lines of nozzles-39f, and 390 of adjacent ducts 35 intersect the-surfaceof'the drum ltlsubstana tially at the same distance from each other and from the centerlinesof adjacent nozzles 39a and 3%,- so that the application of air is substantially uniform. not only be-. neath the ducts 35 but also opposite the spaces between the ducts. In theparticular embodiment illustrated, the ducts 35' have a-width of"7 /2 inches, and there is approximately 2 inches between ducts. The

side parts

38a and 38b of the'walls carrying the nozzles 39 and 390 extend 4 at an angle ,A with respect to themainparts of the walls 38 so as to achieve this uniform air distribution.

For best results and most uniform application of air to the surface of the drum 1% from the nozz.es 39, the spac ing of nozzles 39 shall preferably be /8 inch to 2 inches from neighboring nozzles, both peripherally and longitudinally of the drum, and the nozzles shall preferably terminate A2 inch to 2 inches from the surface ofthe drum 10. In addition, the percentagefree area for flow times the nozzle coefficient of discharge shall preferably be in the range from 1.3 to 2.7 percent. The free area for flow is thetotal area of all of the nozzles at their outlet ends divided by the total surface area of the sheet W to which air application is made from the nozzles. The nozzle coefiicient corresponds. to an orifice coetficient which may be'explained with reference to.FIG. 13. The; orifice coefiicient, referring to FIG. 13 which showsthe flowof fluid through a simpleorific'e 47, is A over A where A isthe diameter of the; orifice and A is the smallest diameter of the fluid; stream proceeding from the orifice; Analogously for anozzle, with no fluid friction for-agiven pressure-drop,ithe fiowwvould'be F v while,

with the friction'thatac-tually exists, the flow isJF Thenozzle co'efiicient of. discharge wouldthen be Fgover F The coefficient of discharge can be easily ascertained by those skilled: in theart for: orifices: andnozzles ofany,

shape using well known chemical engineering principles, such assetforth inzPrinciples of Chemical Engineering, Chapter 3, by-Walker, Lewis, McAdams and Silliland, published by McGraw-Hill BookCo, New York, N.Y.', 1937. With an ordinary simple orifice, its coefiicient may be onithe order of'% while with a properly designed nozzle, the corresponding nozzlecoefficient maybe .94, indicatingv a=substantial difference. Although the nozzles 39 are illustrated asdirecting the air on to the surface of the drum 10, it will be understood that simple orifices may instead: be used; however, due to the different flow behaviorofithe orifices as compared to nozzles, the diametersof the orifices mustbe larger-than the inside diameters of the nozzles to provide the same airflow, The same spacing of the orifices with respect to each other and to the drumsurfacean'd the same product of-thefree area for flow by the coeflicient of discharge are preferably used for the orifices as for the nozzles.

The air that'flows' off the surface of the drum 10 returns to the fan 34, or as exhausted out of the system, flowingin thespaces between the ducts 35'. For the purpose of simply returning the air that is discharged through the nozzles 39 subsequent to impingement on the outer surface of the drum 10', the spacing between the ducts 35 could be closer. However, at times, the wedding or paper, due to some defect, accumulates on the surface of the waddingor paper can be withdrawn from the surface of the drum between the ducts 35, The exhaust air in the hood space 42 exhausts-in part through the duct 43, and

the remaining part is drawn by the recirculation duct 44 for mixture with make up air in the duct 45in advance of' the heater- 46. The provision of this recirculating arrangement for exhaust, air provides the required amount of air for the ducts 35- with an appropriate capacity fan, about 10 percent to 40 percent of the air circulated being fresh or make up air and the balance being exhaust air.

In lieu of the arrangement of nozzles illustrated in FIG. 7, orifices may instead by utilized as previously mentioned. Also, other-patterns of nozzles or orifices may be used in lieu of that illustrated in FIG; 7 to uniformly apply air to the surface of the drum 10. Referring to FIG. 10, orifices 47a disposed on triangular centers may be used as shown. The orifices may have a diameter of inchand maybe-located on corners of equilateral triangles having 1 inch sides. Nozzles may be utilized instead of the simple orifices in this arrangement, but as previously indicated, the nozzles if properly designed for minimum frictional loss will have a smaller diameter than the orifices for the same total air fiow.

Substantially uniform application of air to the surface of the drum It} may be achieved also without the diagonally extending nozzles 39c and 39f or corresponding diagonally extending orifices. This may be accomplished by locating the ducts 35 closer together such as is shown in FIGS. 8 and 9. in this particular embodiment, the ducts are 3.5 inches wide and have a spacing of 0.6 inch between them. As will be observed from FIG. 9 which shows the arrangement of nozzles in the walls 38 of these ducts, the nozzles 39 are provided in patterns of four which includes nozzles 13%, 3%, 39m and 3911. The nozzles 39j and 3912 are located substantially as close to the

side duct walls

36 and 37 as possible, and the nozzles are disposed on diagonal lines or lines disposed helically about the drum extending in such a direction that the four nozzles in one duct 35 will align with four nozzles in an adjacent duct. The nozzles are equally spaced on these diagonally extending lines, and adjacent nozzles in adjacent ducts 35 will be spaced approximately the same distance as the nozzles in any of the ducts on these diagonal lines. The nozzles 39 are disposed on longitudinally extending lines and this is true of the other nozzles as well. The longitudinal lines in the illustrated embodiment are 1.1 inch apart, and the nozzles along each of these longitudinal lines are located 1.25 inch apart which assures an even distribution of air from each duct. Due to the close spacing between the ducts 35 and the location of the nozzles 39 and 3911 as close as possible to the side walls 37, this uniformity of air application exists also between the ducts 35. This spacing of ducts and nozzles is particularly useful in connection with stronger and heavier papers that do not tend to bunch up and accumulate on the surface of the roll 16' necessitating the frequent removal of paper from the roll surface.

The same uniformity of air application may also be had, using the air for cooling instead of heating. This may be in connection with a breaker stack conventionally located behind the drier in a paper machine, such as behind a Yankee drier drum 1% Referring to FIGS. 11 and 12, such a breaker stack may comprise a large bottom roll 48 and

upper rolls

49 and 50 supported by a frame 51. The paper web W may pass through the nips of the

rolls

48, 49 and 50 as shown in FIG. 12. Due to lack in uniformity in the rolls of the breaker stack or due to lack of uniformity in thickness of the paper web W, for example, one or more of the rolls 4?), 49 and 50 may become non-uniformly heated on its surface. Such nonuniform heat distribution on the surface of a roll tends to cause the roll to be undesirably non-uniform in diameter. Therefore, it may be desirable to cool certain sectors of the roll without cooling other sectors so as to bring the roll surface to a uniform temperature across the length of the roll or, more generally, to change the existing temperature profile, giving it a desired different temperature profile. A hood 52 having a plurality of semicircular plenum chambers 53, with arcuate walls 54 in close proximity to the roll 4%, may be provided for the roll 48, for example. The walls 54 are provided with the orifices l? or with the nozzles 39, which are arranged with respect to each other in the same manner as previously described. An air inlet pipe 55 is provided for each of the chambers 53. The same space between the wall 54 and the surface of the roll 4% is preferably provided as between the walls 33 and the surface of the drum 10; the same hole or nozzle spacing of inch to 2 inches is desirable; and the same percent free area for flow times nozzle or orifice coefficient of 1.3 to 2.7 percent is preferably used, so that the sa-rne uniformity of air application is achieved for uniformly and effectively cooling the sector of the roll opposite the plenum chamber 53 to which the cooling air is supplied.

The utilization of the orifice or nozzle spacing of inch to 2 inches, the use of the range of 1.3 to 2.7 percent free area for flow times nozzle or orifice coeificient, and the location of the surface in which the orifices or nozzles are disposed between A; inch and 2 inches of the surface of the roll assures not only uniform air application but provides a desirably high volume of air flow and heat transfer to the surface of the roll, as well as a maximum mass transfer, which in the case of the Yankee drier roll is a maximum drying effect.

It will be observed that both the heating and cooling embodiments of the invention provide generally arcuate surfaces extending around the rolls. In the FIG. 4 embodiment, the generally arcuate surface is provided by the plane walls 38 together with the diagonally extending

end zones

38a and 38b of the plenum chambers 35. The generally arcuate surface in the FIG. 8 embodiment is provided by the walls 38 between the

side walls

36 and 37 which are located closely together for adjacent plenum chambers. The generally arcuate surfaces are at an approximately uniform distance from the external surfaces of the rolls, and the orifices or nozzles extend perpendicularly through the walls in which they are disposed and are so spaced in patterns that the air jets impinging on the rolls are spaced substantially uniformly arcuately of the rolls from substantially one end of the hood to the other and are also uniformly spaced longitudinally of the rolls.

Due to the fact that there is a uniform application of air for the complete surface of the rolls beneath the drier hood, the drying effect achieved is greater than that achieved by conventional air application apparatus that does not provide this uniformity, since the spacing between adjacent ducts or plenum chambers is in effect wasted insofar as air application to roll surface is concerned.

Although I have described my improved uniform air application system in connection with cylindrical rolls, it Will be apparent that the system may also be used in connection with surfaces of other shapes, such as with flat surfaces. The air application system when used in connection with rolls for either heating or cooling the rolls may be used to control the surface temperature profile across the rolls and thus control the diameter profile of the rolls. Such control of diameter profile is particularly important in connection with breaker stacks in which rolls that are unduly large in diameter in certain sectors along their length will cause variation in thickness and other characteristics across the width of the paper passing through the breaker stacks. My improved air application system is not only useful with surfaces and rolls of steel but is also useful in connection with surfaces and rolls of nylon or other material suitable for drying or breaker and calender rolls, particularly for diameter control of the latter.

I wish it to be understood that the invention is not to be limited to the specific constructions and arrangements 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.

What is claimed is:

1. In mechanism for applying air on a roll, the combination of a hood having a generally arcuate surface adapt-ed to extend around the roll at an approximately uniform distance therefrom, means defining a plurality of plenum chambers in said hood extending longitudinally of the roll and including a wall for each chamber extending approximately parallel with the roll surface and which walls collectively define said generally arcuate surface, said walls each having a plane portion and two end zones extending at angles with respect to said plane portion, and means for applying air to said plenum chambers, said plane portions and said end zones being provided with a plurality of openings extending transversely therethrough so spaced as to apply air jets at points which are substantially uniformly spaced longitudinally of the roll and also arcuately of the roll substantially from one end of the hood to the other. i

2. A hoocl for applying air on a roll and having a ge1erally arcuate surface to extend around the roll at an ap iroximately uniform distance therefrom, said hood including means defining aplurality of air conducting plenum chambers in the hood Which extend longitudina'lly of the roll and which have walls" facing the roll and defining said arcuate surface and also have side walls, said side Walls of adjacent ones of said plenum chambers being substantially equally spaced and defining air eiihau's't passages therebetween, said roll facing Walls being provided with rows of openings therethrou'gh extending longitudinally of the roll and including two side fows for each of said plenum chambers adjacent the opposite sides of the plenum chamber and including also at least one additional intermediate row, each of said rows ineach of said roll facing Walls being' spaced a predetermined distance apart ar'cuately of the roll and said plenum chambers being so closely disposed to each other that the adjacent side rows of adjacent ones of said plenum chambers are also spaced substantially the same distance apart as the rows in each of said roll facing walls and the openings in immediately adjacent ones of said longitudinal rows being staggered and so located with respect to each other that the openings lie on lines extending helically around the roll so as to apply jets of air from said chambers on the surface of the roll which are substantially uniformly spaced both longitudinally of the roll and also arcuately of the roll.

References Cited in the file of this patent UNITED STATES PATENTS 1 ,488,953 Tensfeldt 6. Apr. 1, 192 4- 23 0 4, 818 Grupe Dec. 15, 1942 2,878,583 Spooner Mar. 24, 1959 2,919,495 Underhay Ian- 5,' 1960 2,928,135 Dreyv Mar. 15, 1960 3,012,335 Allander Dec. 12, 1961 FOREIGN PATENTS 727,058 Great Britain Mar. 30, 1955

Claims

2. A HOOD FOR APPLYING AIR ON A ROLL AND HAVING A GENERALLY ARCUATE SURFACE TO EXTEND AROUND THE ROLL AT AN APPROXIMATELY UNIFORM DISTANCE THEREFROM, SAID HOOD INCLUDING MEANS DEFINING A PLURALITY OF AIR CONDUCTING PLENUM CHAMBER IN THE HOOD WHICH EXTEND LONGITUDINALLY OF THE ROLL AND WHICH HAVE WALLS FACING THE ROLL AND DEFINING SAID ARCUATE SURFACE AND ALSO HAVE SIDE WALLS, SAID SIDE WALLS OF ADJACENT ONES OF SAID PLENUM CHAMBERS BEING SUBSTANTIALLY EQUALLY SPACED AND DEFINING AIR EXHAUST PASSAGES THEREBETWEEN, SAID ROLL FACING WALLS BEING PROVIDED WITH ROWS OF OPENINGS THERETHROUGH EXTENDING LONGITUDINALLY OF THE ROLL AND INCLUDING TWO SIDE ROWS FOR EACH OF SAID PLENUM CHAMBER ADJACENT THE OPPOSITE SIDES OF THE PLENUM CHAMBER AND INCLUDING ALSO AT LEAST ONE ADDITIONAL INTERMEDIATE ROW, EACH OF SAID ROWS IN EACH OF SAID ROLL FACING WALLS BEING SPACED A PREDETERMINED DISTANCE APART ARCUATELY OF THE ROLL AND SAID PLENUM CHAMBERS BEING SO CLOSELY DISPOSED TO EACH OTHER THAT THE ADJACENT SIDE ROWS OF ADJACENT ONES OF SAID PLENUM CHAMBERS ARE ALSO SPACED SUBSTANTIALLY THE SAME DISTANCE APART AS THE ROWS IN EACH OF SAID ROLL FACING WALLS AND THE OPENINGS IN IMMEDIATELY ADJACENT ONES OF SAID LONGITUDINAL ROWS BEING STAGGERED AND SO LOCATED WITH RESPECT TO EACH OTHER THAT THE OPENINGS LIE ON LINES EXTENDING HELICALLY AROUND THE ROLL SO AS TO APPLY JETS OF AIR FROM SAID CHAMBERS ON THE SURFACE OF THE ROLL WHICH ARE SUBSTANTIALLY UNIFORMLY SPACED BOTH LONGITUDINALLY OF THE ROLL AND ALSO ARCUATELY OF THE ROLL.