US1557423A - Drying method - Google Patents

Description

Oct. 13, 9 1,557,423

C. C. COLBERT ET AL DRYING METHOD Original. Filed Oct. :5. 1925 s sheets-shut 1 fizz/972%.; C/Zardas 6. 62567%. Goyeffiesfarz f Oct. 13, 925.

c. c. COLBERT ET AL DRYING METHOD Original Filed 0012.0, 1923 s sheets-shut 2 f 7%.- iarfe g bfierf Oct. 13, 1925.

C. C. COLBERT ET AL DRYING METHOD Original Filed Oct. 5. 1923 5 Sheets-Shoot 5 5 gm &7 N 665 Q, .NN 7 N f m L x Nn\ Q N R \m 7 W Nmm h \N D 4.." m m m NA Q ll/ 5 m #4 M mm 44.4, MN w\ Q \m N Patented 0a. 13,1925. 1 UNITED STATES I PATENT, OFFICE;

CHARLES C. COLBERT AND GEORGE E. PRESTON, or ELKHART, INDIANA, AssIeNons'ro AMERICAN COATING nuts, or ELKHART, INDIANA, AooRPoRATIoN or INDIANA.

nnYING METHOD.

Original application filed Jctober 3, 1923, Serial No 666,268. Div i ded and this application filed Illec'ember 1, 1924. Serial No. 753,163.

To all whom it may concern."

Be it known that we, CHARLES C. Cor.- nnn'r and GEORGE E. PRESTON, citizens of the United States, and residents ofElkhart, in the county of Elkhartand State of Indiana, have invented an Improvement in Drying Methods, of which the following is a specification. The present invention is intended to pro; vide a method for conducting a drying operation such as hereinafter indicated in an advantageous manner with respect to the material undergoing treatment, 'aswell as with-regard to such consideration as economy and rapidity of operation.

The invention will be readily understood by reference toone practicable form of apparatus for practicing in the annexed drawings.

In said drawings: Figs. 1 and 2 collectively represent a longitudinal vertical section of a drying room incorporating the illustrative apparatus, Fig. 1 showing the first half and Fig. 2 showing the succeeding half thereof. These views are partly diagrammatic, omitting many mechanical details. r

Fig. 3 is a cross section. I Fig. 4: is a. side view of a portion of conveying means. I v Fig 5 is a cross section on the line 5 5 of l ig. 4Q 1 i Reference is made to application Serial No. 666,263, filed October 3, 1923 ofwhich this application is a division, for a fuller disclosure and descriptionof the apparatusselected for illustration, and WhlOh is herein described in connection with a process of drying coated. paper board.

A continuous web of coated paper board is designated in the drawings by the numeral 1. A large quantity of the continuous board, accumulated in undulating formation or in a succession of open folds, is ex- .pdsed to drying treatment in the illustrative 5 which is shown incorporated in a 2. The drying process may,

apparatus, drying room progress as the board. moves along, or through the room, while the freshly eoated board is drawn into the receiving" end of the room and the dried board is withdrawn from the other end for finishingthe coated surface of the board and subdividing or reeling the finished product,

such method, shown.

Contact with the coated surface of the board should be avoided until after it is substantially'dry. In this instance, board hav-' mg a liquid coating applied to a selected surface runs with its coated side uppermost into and through the drying room, in which. itdis supported from its 'under or uncoated 51 e. I In Fig. 1, the boardis shown running into the receiving end of the dryingrroom and being hung up in-festoons on transverse sup- .ports which in this instance are provided by -so-called sticks. Such sticks areindicated at 5 in' Figs. 3, 4 and 5. These sticks preferably consist of round wooden poles having theirends flattened to rest on sup porting or conveying means without tendency to turn or roll. They should be .of sufficient diameterto provide ample supports. from which the board may hangwithout sharp bending] In said application'Serial No. 666,268, means are shown for providing supports either-by single sticksor pairs of sticks.

The sticks 5 are feeding board at appropriate intervals of time to allow desired lengths of the board to hand between the successively presented sticks. This may be accomplished by elevating means 6' consisting of a pair of endless chains arranged at opposite sides of the board and having suitably spaced lugs for engaging and-forwarding the sticks; Said elevating chains pick up the, sticks from lower sprocket wheels of the chains, and

delivered by a conveyor 9 as explained in said application Ser. No. 666,268..

The elevating chains deli'venthe sticks represented by successive sections or sets of chains 10, 11, 12,13, 14, 15, 16, 17. It will be understood that each set comprises a sticks-with the hanging board, the sticks with the hung-up board to conveying means.

brought under the in curved'guides '8 arranged coaxially with'the i into which guides the sticks are successively being transferred from one set of chains to another. These successively arranged s teef ar c ains run at difierent speeds as presently to described for changing the spacing of the sticks, with accompanying contraction or expansion of the festoons of board carried thereby. By running the first pair of carrier chains 10 at an appropriate speed in relation to the "elevating chains 6, the sticks carrying thehung-up board are placed upon said chains 10 at desiredintervals apart, preferably at fairly wide intervals so as to carry the festoons of board in comparatively distended condition for an initial drying treatment.

In this instance, the chains 11 to which the sticks are delivered by the chains 10 run ata somewhat slower speed than the preceding chains, thereby receiving the sticks at closer intervals and contracting the festoons, so that-a greater quantity of board,- accumu lated in closer formation; is submitted to drying action. in the region of-v the room traversed by said'carrier chains -11.

are transferred to the ch'ains12 which run tions 11, 13, 15and 17 running at relative-- 1y slow speed. i

' From the relatively slow running chains 11, the sticks carrying the festoons of board .at a relatively fast speed sov as to take the sticks at wide intervals apart and thereby spread out or expand. the festoons.

The succeeding chains 13 run at a rela-= tively slow speed for again spacing the sticks at closer intervals and narrowing the festoons. So on through the conveying system, the festoons are carried in alternately expanded and contracted condition, and at 35 varying rates. of speed; the sections 12, 14

and 16 of the conveying system running at relatively fast speed and the alternating sec- As the drying process progresses, it is desirable to reform the festoons in order to I change the points of suspension of the board and expose the board differently to the drynig medium in the room. For this purpose '45} the boardmay be shifted longitudinallyof its supports by training the board over one or more overhead rollers such as indicated at 18, 19 and 20. These rollersare preferably associated with the fast running sec- 'tIons 12, 14 and 16 of the conveyor system.

One of said fast running conveyor sections with an overhead shifting roller is shown 1n Fig. 3, from which it will be seen! that the board trained over the roller 18 is withdrawn from the successively advancing sticks 5 and is re-engagedby said sticks beyond the roller at different-points from those previously engaged by the respective sticks.

I Thus the points of suspension of the board ar'e automatically changed. The said over head roller 18 is power driven at appropriate speed for withdrawing the board from the sticks and effecting a desired lineal advancement of the board sticks.

To mamtam desired spacing and correct relative to the transverse alignment of thesticks on the fast running carrier chains 12, 14 and 16, as well as to prevent dislocation of the'sticks duri'ngshifting of the board relative to its supports, said chains are provided as shown in Fig. 4 with stick-engaging lugs 21, and certain retarding devices are arranged to resist movement of the sticks and thus maintain them in engagement with said lugs. The

specific means shown in Fig, 4is as follows:

Rails 22 having inclined or beveled front ends 23 are arranged beside said carrier' chains and rise gradually above the level thereof but not above the projections of the chain lugs 22. Above Ithese rails are hanging-bars 24 connected by bolt and slot con' nections 25 to suitable hangers, permitting said bars to be raised. A stick 5 transferred from theslow running chains 11 to the fast running chains 12 rides up the beveled ends 23 of the rails 22 and against the under beveled ends 27 of the upper bars 24. This causes the stick to pause until its ends are gages the upper bars 29 and is .forced out between the rails and the under surfaces of the upper bars bearing on the stick. Thus the stick resists dislocation by the pull'of the hanging board as it is drawn'past the stick over the overhead roller, and correct transverse alignment of the sticks on the parallel chains is maintained. Afterpassing under the overhead roller and to posi tion for re-engagement of the board, the stick may be caused to ride over inclined obstructors 30, thus insuring its alignment by maintaining it against the chain lugs 21. It will be understood that each board shifting section of the conveying system is equipped with means of the character just described.

From the foregoing description, it will be seen that the coated board hanging in fes toons or folds is-conveyed through the drying room by a succession of conveying means running at alternate ratesof speed, so as -alternately to contract and spread out the festoons to drying action; while the conveyance of the board in this manner is accompanied by one or more shi'ftings of the board to change its points of suspension, or

in other .words to cause the board to hang,-

on the sticks from portions which were previously suspended between the sticks. These actions promote efiicient and uniform drying of the board; while the successive 'shifting of the points of support prevents for- 'mation of undesirable bends or' ruffles in the toward the upper or coated side of the board, and a. number-of nozzles 33 in the floor of the room for blowing heated air against the under or uncoated side of the board. In Fig. 1, manifolds for supplying festoons of board are conveyed a consider-- the hot air to the overhead ducts and bottom nozzles are respectively indicated at 34 and 35, these manifolds being connected with a suitable blowing apparatus 36 which may be supp-lied with hot air from any suitable source; or if preferred air, may be heated .in the blowing apparatus'by a steam pipe'coil or otherwise. In drying coated board, it is desirable to subject the board to a gentle and gradual preliminary drying, without exposure of its coated surface to direct action of heat currents, and then to submit the board to a more pronounced drying action in the presence of heat currents directed toward, its

coated side. By this treatment there is obtained an advantageous preliminary evaporation of moisture and seasoning of the body of the board, and its coating acquires a setting and consistency adapting it to withstand the ensuing more severe drying action.

It will be observed by reference to Fig. 1, that the heating system of the illustrative room is so arranged that the hanging able distance beyond the receiving end of the room before coming within the range of .the bottom hot air 'nozzles 33, and are eon-.

veyed a further considerable distance before coming within the range of the overhead hot air ducts 31: and that the festoons are within the range ofboth the overhead and underneath heat blasts for a limited distance,

after which the drying of the board is con-- tinued by the overhead blasts. The specific arrangement shown is such. that the 1 festoons ,first encounter the action of the underneath blasts while conveyed in comparatively distended condition by the first set of longitudinal carrier chains 10, and ar subsequently acted upon by said blasts While conveyed in closer folded condition by the carrier chains 11. r I K This arrangement providesin the drying room a region ofpreliminary drying, the two general freshly coated board is conveyed with its festoons fairly distended or spread through and setting of the coated surfaee of the board. Then the festoons come within the range of the underneath heat currents, blow ingupwardly against'the under or uncoatcd side of the board and into the spaces between. the festoons, warming the body of the board and further advancing the drying. This stage of treatment, commencing while the festoons are moving in relatively distended condition, continues in the illustra- Thus an efi'ectual progressive drying ensues in advance of exposure of the coated surface of the board to the direct action of impinging heat currents.

According to the specific arrangement shown, the festoons are brought within the range of the overhead 'hot air ducts 31 while conveyed in comparatively contracted condition by the slow running chains 11. As the hanging board is further conveyed along the drying room, by a number of successive sets of carrier chains. it is exposed under varying conditions and difl'erently presented to the currents of heated air discharged by, said overhead ducts; and also continues for a certain distance to be exposed to the heated air currents ascending from the floor nozzles 38.

In the regions of the drying room traversed by the slow running sections 11, 13, 15. 17 of the conveying system, extensive accumulations of the board in narrow festoons are maintained, 'so that the volume of heating medium acting during any given interval in these regions is expended upon a relatively large quantity of material, while given portions of the material are exposed ties of theboard. Thus the drying action per unit oftime per unitarea of material is substantially greater than that in the zones of protracted drying. Furthermore the drying effect in the regions of the fast running conveyor sections is promoted by the spreading out of the board. and still further accentuated if the board is run over the overhead shifting rollers in proximity to the overhead air ducts. These regions may accordingly be referred to as zones of accelerated drying. I

By changing the points of suspension. of

board, involving reformation of the.

ness of the board. By appropriately reforming the festoon's or effecting appropriate longitudinal shifting of the board a suflicient number of times, the boardmay be dried substantially uniformly throughout its length.

As the board moves rapidly over an over head shifting roller,"its coated surface is uniformly subjected to the action of the hot air blasts in close proximity to the ducts resents a period of'relatively pronounced- 31, as will be apparent from Fig. 4:. This again contributes to eflicient and uniform drying. It may however be unnecessary or undesirable in some cases, depending upon the character of the board under treatment and to nature and thickness of the applied coating,- to run the board over all the overhead rollers, or to expose its coatedsurface to close action of the hot air blasts in every zone of accelerated drying, and especially the first such zone. For instance, in some .cases'the liquid coating may be in too fresh or wet a condition for close exposure to hot air blasts while in the region of the drying roomtraversed by the chains 12; and in the case of board coated with a thin or quickly drying composition close exposure to the hot air currents in all of the zones of accelerated drying might result in too severe or sudden drying, rendering it expedient to carry the board under one or more ofthe overhead rollers, or to effect the shifting without such close exposure. discharge slots of'the overhead ducts may be closed at these portions overlying a roller, so as to permit running the board over'such roller for shifting purposes withoutaceompanying severe drying treatment.

With the heating arrangement shown, the board undergoes a period ofdrying in a medium discharging against its 'uncoated side, overlapping with a period of drying by a medium discharging toward the coated side of the board; The overlapping interval, in .Which the board is simultaneously exposed to the action of both the descending and ascending currents of heated air, repdrying. which in this instance occurs in successive steps or stages infthe region of the drying room traversed'in part by the slow running chains 11, the fast runnmg chains For instance, .the bottom I 12,-andin the slow running chains 13.

By thus submittingthe board under varying conditions to the conjoint action of the astending and descending currents of heated air, after the period of progressive preliminary drying heretofore desoribed, the board-- is brought to a condition in which it isade quately responsive to the'succeeding stages of drying action, which in this instanceare a 4 continued by the descending currents of heated air'upon the coated side of the board until and-,if desired, during the; accumulation of the board in the delivcryen'd of the. drying room.

The operations described provide a method by which coated paper board is advantageously dried by progressive steps or stages of drying action of difiterent kinds and effects, including recurrent heat treatments under varying conditions. in the presentation of the board thereto, for 'ob-' taining efficient and substantially uniform drying: in the time interval between 'the' coating and finishing of the board. By this method aproduct thoroughly and uniformly dried and substantially free of flaws may be obtained.

Froman accumulation of the dried board hanging in the delivery end of the apparatus, either on the chains 17 or'a succeedingset of chains or supporting means associated therewith, the board may be continuously withdrawn for calendering orfinishing its coated'surface and subdividing the finished product into cut sheets. 1 Asthe board runs from the drying room, it'may be exposed to the action of hot air blasts discharged from suitable pipes, one of which is shown at 38 in Fig. 2, for the purposeof additional or super-dryin tion, or to heat-the coated surface a vantageously for 'a calendering or finishing operation. We clalmz' web undergoing treatment through said currents; subjecting the web to-a preliminary drying and seasoning action by said medium in a relatively quiescent state and J subsequently subjecting the web to the moving currents of drying medium under varying conditions providing drying treatments of different effects including recurrent treatments upon differently presented portions of the'web.

2. A drying method characterized by exfl posing the web under treatment inundul'ati' ing condition to a drying medium in a rela- 125 tively quiescent and temperate state; and

subsequently maintalning said undulatingweb for a relatively prolonged period currents of said medium impinging on the web, inbluding successive periods of action 139 of said currents upon opposite sides of the Web; and successively varying the undulating condition of the web while undergoing drying action by said impinging currents.

. 3. A drying method characterized by exposing the web in undulating formation and while successively expanding and contracting the undulations to drying'actio'n by heat currents moving transversely of the web.

4. A drying method characterized by preliminarily drying the webnnder treatment in a relatively quiescent and temperate atmosphere and subsequently exposing the web to heat currents under such varying conditions as to provide periods of pro tracted drying alternating withfintervalsofv accelerated drying. W I -5.' A drying method characterized by maintaining'undulations of continuous material moving through a plurality of zones of.

drying action, including 'a first zone of gentle dryingya succeedingzone of dryin by actionof heat currents against one si e of the material, and-succeeding zones of'drying by action of heat currents first upon both sides of the material and then u on the opposite side from that first submitted -to said heat currents.

.6. A drying methodcharacterized by subjecting the web under treatment to a gentle initial drying in a quiescent atmosphere. and

subsequently exposing said web to drying erated stages in heat; currents directed action in alternating protracted andaccelagainst the web.

drying method characterized exposing a coated weblto progressive stages of drying action without exposure of its coated surfaceto direct action'of heat currents and then progressivel drying said web by heat currents directe against said coated surface.-

' 8.- A drying method'characterized "by exposing'a web havin a coatingvappliedto a selected side thereo to a period ofdrying action in heatcurrents, discharging against the uncoated side-of the ,web and an overlap wping period of drying action in heat cur-' maintaining "progressively of the dried web rents discharging upon the coated side of the web, 1 9. A drying method characterized by exposing .the web under treatment in various conditions to successive stages of dryin action including stages of treatment by eat currents'acting against one side of the web overlapping with a succeeding period of 11. A rying method characterized by.

the web undergoing drying action in un ulati'ng formation while' successivelyjcontracting and expanding the undu: lations and reforming the undulations.

1 12.:A drying method characterized by exposing a coated web" under various conditionsto successive stages of drying. action by heat currents acting first upon, the uncoated side of the web and subsequently for arelatively prolonged period acting upon the coated side. I

13. A drying method characterized by maintaining an undulating formation? of continuous material and successively 'reforming the undulations while COIltllilIOllSl.

exposing said material todryingaction.

l4=.-A drying method characterized by subjecting a coated web toprogressive stages 'o f drying action-without exposure of its coated surface to direct action of heat cur-. -rents and. subsequently exposing said web to drying action in alternating'protracted so 7 I and' accelerated stages in heat{ currents di-g rected against the coated surface of the web.

15. A dryingr blowing heated air upon the coated surface as it emerges f'rom thedry ing operation.

' testimony whereof, wehave signed our names to this s ecification.

. Cf-lARLES C.- COLBER GEORGE E. -PRES TQN.- I

method. characterized by ying a coated web and

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