US2024079A

US2024079A - Apparatus for drying paper in a continuous web

Info

Publication number: US2024079A
Application number: US725218A
Authority: US
Inventors: Whiting William
Original assignee: WHITING PAPER Co
Current assignee: WHITING PAPER Co
Priority date: 1934-05-11
Filing date: 1934-05-11
Publication date: 1935-12-10
Anticipated expiration: 1952-12-10

Description

W. WHITING Dec. 1o, 192.5.

APPARATUS FOR DRYING PAPER IN A CONTINUOUS WEB Filed May 11, 1934 |||l||||||||||||||lll| ||||11 1W festoon. These fe'xpedients have not proved satis- T GFFICE FOR DRYING PPER IN A` 1 CONTINUOUS WEB Williaml Whiting, no1yoko, Mass., assignor to Whitingv Paper Company, Holyoke, Mass., a corporation of Massachusetts Application Moy 11, 1934, seriai No. '125,218

2 claims. 'Ihlsinvention relates to apparatus for -drying paper' in a continuous web. Loft dried paper has a number di' advantages in appearance and quality andmany attempts have been made to secure similar laltipearance and 7quality by continuous methodsan'd machines. In one common arrangenient the web is carried successivelyaround a series of steam heated drumsand according to another me'thod the web ls formed into a traveling factory in securing results equivalent to loft drying. In the case ofheated drums the shrinking of thepapor about the-umm set op strains which are detrimental to the quality and appearance and in the festoon method uniform drying conditions Aare difficult if not'impossible to obtain since ex'- cessive evaporation at the start reducesthe tempelrature .at that .point and the humidity varies from one end o f thef line to the; other. Also the weight of the paper in the festo'on loops places an objectionable strain on the paper at' the festoon bars, and the bars leave marks en the paper.

j 'I'he object of the invention in general fis to attain the benecial results of loft drying or festoon drying coupled with the speed, eiliciehcy 'and economy of machine drying. It is well understood that the lett drying method produces a strong,

tough-paper with its cockled surface characteristic of high grade paper, due to the fact that the wet paper is allowed to dry in a thoroughly relaxed condition wherein its natural shrinkage Y produces 'no strains tending to weaken the 'ber such as occur inthe usual machine dried product.

Having this in mind I have devised an apparatus which haridles the' web in a continuous run 'as it comes from the paper making machine, and during its drying process keeps it traveling without strain or tension and so that it may be exposed with substantial uniformity-on both sides to the action of the drying air. At the end of its run when the. paper 'is completely dry and may withstand tension without' injury-it may be wound upin a nished roll-or subjected to further nnishing processes as may bedesired Important features of theinyention to be observed are tirati-the web of paper formed on the paper making machine is delivered therefrom in single long runthrough a'conflned and controlled drying atmosphere and withsufficient initial pro-' pelling force to keepthe web traveling from 'one end to the other of its run.' A conveyor is provided to support the paper during its run but imparts no pulling tension thereto, the paper being permitted ,to ride thereon in a thoroughly relaxed and unstrained condition. At the dry end of the run a tension-barrier is provided whereby the .completely dried web may be pulled along after passing therethrough and which prevents said pulling tension front being transmitted backwardly tothe drying web on the conveyor.

Other and further advantages will be apparent from the following speciiicationandclaims.

In the accompanying drawing which illustrates one, embodiment of the invention; i Fig. 1 is a sideview of a drier unit constructed yaccording t the invention; f `Fig. 2 is a plan 'view on a larger scale of a portion of the drier structure, parts being broken away; o

Fig. 3 is asection substantially on line -3-3 of Fig. 2; v v

Fig. 4 is a section Fig,f2;'v and Fig. 5 is a fragmentary elevational view showing an attenuation arrangement of the web supf z, 24,079 UNITEDVSTATES' PATEN substantially o n line 4*'-4 of series of drying cylinders I, an elongated drying chamber 2 provided with a blower 3 and an air conditioning unit 4. The drying cylinders I may be of usualconstructicn and serve to lower the initial moisture content of the paper to the point where shrinkage starts to become a. troublesome actOr. From the cylinders I' the paper web enters the chamber-2, best shown in Figs. 2, 3 and 4. The chamber 2 is divided lengthwise by a ver tical partition 5 into a walkway 6 and a main chamber or tunnel l. Mounted in the tunnel 'I are a plurality of transverse rolls 8 adapted to support the paper web indicated at I0. The rolls 8 ,are formed of spaced narrow slats II and are rotatably journaled in partition 5 and a wall I2 of the chamber.

are provided with two pulleys Il by means of which each succeeding roll is driven from the preceding roll by belts I5, the initial roll being driven from a motor I6 by a belt I1.' The speed of the motor7 is vcontrolled by a control unitindicated at I 8 which may be of .any conventionalA construction. The surface speed ofrolls 8 ismadc such as to .oat the web forward at the initial speed imparted to it by the cylinders I, so that no drag or strain is placed on the web in its pase sage, through the tunnel and the paper .while The shafts I3 of the rolls extend outwardly beyond the chamber wall I2 anddrying isssubstantially as free vfrom restraint is the case in loft drying. In order to' adjlistthe speed of the rolls 8 to accommodate the shrinkage of the web as it dries, means are provided at intervals for `modifying the speed of the succeed- -ing' rolls and in the embodiment -shown this is accomplished by substituting cone pulleys 20 for the-outer pulleys IB of two adjacent rolls 8. The

shaft of one of the adjacent pair of rollscarry- 1 ing the cone pulleys is made hollow-to receive a shaft 22 passing through the pulley and having its end beyond the pulley screw threaded and journaled in a bearing j23^formed on a bracket 25 secured tothe wall I2. A belt shifter 26 is threaded on the shaft 22 and engages the belt 2l connecting the cone pulleys. The opposite end of shaft 22 is provided with a handwheel 30 acces-.- sible from the walkway 6 by which the belt 28l may be shifted to Iadjust the speed of rolls 8. In order that the attendant may inspect the traveling web windows 3i are provided at intervals in the tunnel wall. A transverse metal partition is positioned across the tunnel forming with the top of the chamber an air duct 36 spaced-above the traveling web. Spaced transverse metal partitions .31 and 38 form a similar air duct 40 spaced below the traveling web. Partition 38 andthe oor of the chamber form a return duct 4I as later described. Air ducts 36 and 40 are closed at their ends adjacent the forward end of the tunnel as indicated respectively at 42 and 43 inFig. 1. Air is forced into the 'ducts at a point adjacent their rear ends by a blower 44 of anysuitable type, driven by a motor 45. As shown in Fig. 3 the blower discharges through branch ducts 46 and 41 connecting respectively with ducts 36 and 40.

As best shown inl Figs. 3 and 4 the partitions 35 and 31 are provided with a plurality of apertures 50 formed by making U-shaped cuts in the partitions, the metal within the cuts being bent outwardly at an angle of substantially 45 to form deilectors 51 extending into the air ducts in the path ofthe air flow and directing the' air into the tunnel against the moving web of paper. As shown in Fig. 1 the air passing into the tunnel `through the aperturesA 50 is discharged at the end of the tunnel into thevreturn duct 4I by which it is returned to the blower through. duct 53. Fresh air is also supplied to the blower through an opening 54 formed in a casing 55 in which is positioned an air Washer 56, an air lter 51 and a heater 58, the vlatter being supplied with steam through a pipe 59 having a valve 60' by means of which the temperature offthe air may be controlled. If the fresh air entering the air system is very dry the moisture expelled from the paper tends to bring the circulating air to the desired humidity. An air outlet 6l provided with an exhaust fan 62 and'controlled by a damper 63 permits discharge of the moisture ladened air at a rate such that in combination with the dry air entering through opening 54 the humidity of the air circulating in the tunnel may be maintained at the desired humidity as indicated by wet bulbs (not shown) positioned at convenient points in the tunnel andVv viewable through the windows 3|. p y

lThe paper web is discharged from the tunnel. over a turtle back through a tension control devicel 66 to a power driven wind up 6l` of any suitable kind, the tension device being adjusted to prevent the wind up from exerting drag on the paper web in the tunnel.

It will be seen that the web moves continuously through the tunnel withoutsubstantial tension and substantially free from restraint as it dries.

The narrow slats I'I ywhich form the surface of the rolls move as Ypreviously pointed out at sub stantially the surface speed of the paper and no marking or marring of the surface of the web takes place as it advances through the tunnel.

In Fig'. 5 is shownan alternative arrangement in which the rolls 8 are not positively driven but are placed on an incline so that the paper advances freely by gravity under the initial movement imparted by the cylinders I.

I claim: 1. In an apparatus for drying material in a continuous running web, in combination, a substantially straight line drying tunnel, a plurality of drying cylinders positioned at the inlet end of 5 the tunnel between which the web passes and by which the moisture content of the web is reduced to a point short of where substantial shrinkage occurs, said cylinders -advancing the web into the drying tunnel..a web conveyor in the 10 drying tunnel which receives the web from said vvcylinders, said conveyoncoxnprising a series of slatted open rolls of relatively large diameter, the rolls` being spaced apart so that thetraveling web sags between adjacent rolls and the shape of the 15 portion of the web supported by each roll conforms to the curved surface of a section of a cylinder formed by passing a plane through-each `cylindrical roll parallel to its longitudinal axis.'

stantially without tension, means for causing currents of air to ow in said tunnel along both .the upper and lower sides of the traveling web, and means to direct said air currents against3 vthe web, with a component of motion inthe direction of web travel, throughout the length of the tunnel.

2. In an apparatus for drying material in a continuous running web, in combination, al sub- 35 stantially straight line drying tunnel, a plurality of drying cylinders positioned at the inlet end of the tunnel between which the web passes andv by whichthe moisture content` of the web is re.

duced to a point short of" where .substantial 4K0v shrinkage occurs.. said cylinders advancing. the web into the drying tunnel, a webv conveyor in the drying tunnel which receives the web from said cylinders, said conveyor comprising a series of slatted open rolls of relatively large diameter, 45

the rolls being spaced apart so that the traveling web sags between adiacent rolls and the shape' A of the portion of the web supported by each roll conforms to the curved surface of a section of a cylinder formed by passing a planethrough each 5 cylindrical roll parallel to its'longitudinal axis, means extraneous of said web' for, driving the supporting rolls, other means for 4adjusting the'speed of certain rolls with respect to other rolls so that 55 all the rolls are driven at a speed regulated to the shrinkage of the web and the initial speed imparted to the web by the drying cylinders whereby the web is advanced through the tunnel substantially without tension, partitions placed in the tunnel to form air ducts above and below -the conveyor, said ducts being connected to a being so positioned 'that air currents passing through the air ducts are directed onto both sides of the web with a component of motion in the direction of travel ofthe web, and a discharge duct for removing the air forced into said tunnel.

WILLIAM WHITING.