US2105711A - Method for producing layers of distended fibrous material - Google Patents

Description

Jan. 18;v 1938. e; WEATHERED,

METHOD FOR PRODUCING LAYERSHOF DISTENDED FIBROUS MATERIAL Filed Jan.. 22, 1936 4 Shet-Sheet 1 Jan. 18, 1938.

G. C. WEATH E RED METHOD FOR PRODUCING LAYERS OF DISIENDEDFIBR OUS MATERIAL Filed Jan. 22, 1936 4 Sheets-Sheet 2 Jan. 18, 1938., G. Q-WEA THERED 2,105,711

IE THOD'FOR PRODUCING LAYERS OF DISTENDED FIBROUS MATERIAL Filed Jan. '22, 1956 4 Sheets-Sheet s Jan. 18, 1938. s. c. WEATHERED IET ODFQR rnonucmc LAYERS or DISTENDED FIBRQUS MATERIAL Filed Jan. 22, 19:56 4 Sheets-Sheet 4 Patented Jan. 18, 1938- UNITED STATES PATENT OFFICE A 7 2,105,711 DIS- Celluioam Corporation, Chicago, 11].,

poration of Delaware Application. January 22, 1936, Serial No. 60,215

3Claims.

The method hereinafter described relates to the production of layers of distended fibrous material of the character set forth in the Bryant Patent No. 1,740,280, issued December 17, 1929. The

5 product therein described is made from cellulose fibers which, mixed with a high percentage of water in the form of a thin mix, are treated with a foaming agent, particularly saponin, and agitated, which results in the production of a foamy mass which after drying maintains the form of a loose or fluffy mass of fibrous materials adapted for numerous uses, particularly for insulating,

hospital use, sanitary bandages, and the like.

In the production of such material, it is cus- Q tomary to prepare a thin mix, and after the same has been foamed by agitation to the desired extent to discharge a layer thereof onto the moving wire of a Fourdrinier machine, whereon the same is subjected to suction to remove a portion of the liquid and thereafter fed through a drier, from which the material emerges in the form of a relatively thick and coherentlayer of light fiufiy distended fibrous material having a surface skin formed thereon by compacting of the surface fibers under suction, in which form the layer is cut to the desired lengths and used for the intended v purpose. The steps involved in' the production 01. such layers are set forth and described in the Bryant Patent No. 1,841,785, issued January 19, E0 1932; the Bryant Patent No. 1,870,279, issued August 9, 1932; and the Bryantv Patent No. 1,929,090, issued October 3, 1933.

In the general method involved in the production of distended fibrous layers as set forth in the i5 foregoing patents, difliculty in commercial production has heretofore been experienced in maintaining uniformity in the thickness and density of the layer by reason of the fact thatheretofore means were not provided to definitely regulate the quani0 titles of fiber and saponin and water fed into the.

mixv or to precisely control the discharge of the mix onto the'wire of the Fourdrinler machine, and the present invention is directed to a method for overcoming the dimculties above mentioned and it for securing greater uniformityin the thickness and character of the resulting product under con ditions permitting rapid production of the material by a continuous operation. The present invention, therefore, is directedto 59 the method provided for rapidly and uniformly feeding the fibrous material in relatively small particles or masses; to the measuring of the fibrous material and the liquid mixing agents employed; to the steps provided for insuring a comll plete and uniionn'mixture of the constituent materials prior to the discharge, and to the regulating of the discharge of the mix onto the wire of the Fourdrinier machine in the form of a layer of uniform thickness and homogeneous character.

Further objects and details of the invention will appear from a description of the same in conjunctanks, the measuring valve, and the agitating tank;. I

Fig. 4 isan end view of the agitating tank with the discharge gate as viewed from line 4 of Fig. 3; Fig. 5 is a perspective view of one of the rotary stirrers or paddles: a

Fig. 6 is an enlarged cross sectional view of the measuring valve for measuring all charges of the mix;

Fig. 7 is a longitudinal section of the same on line I; and

Fig. 8 is an enlarged detail of the ratchet mechanism for controlling the rotation of the measuring valve.

Referring first to the general method involved, as illustrated in Fig. 1, the fibrous material is first of all subjected to a beating operation in a beater tank 20, which is provided with a circuitous channel 2| aflorded by anouter continuous wall 22 and an inner continuous wall 23. Across the channel thus formed extends a heater roll 24 which is rotated by a pulley 25 and a belt 26 leading to a motor 21.

The fibrous material, in the form of 9. till slurry, containing about 5% fiber and 95% water,.

is acted upon in the heater for a period of time which may vary from thirty minutes to two hours or more, depending upon the extent to which it is desired to hydrate and gelatinize the fibers, but for most purposes the beating operation will continue for about an hour, in accordance with the principles set forth and described in the Bryant Patent No. 1,841,785, previously mentioned.

The mix is withdrawn from the beater through a pipe 28 leading to a pump 29, which thereafter elevates the pulpthrough a pipe 00 to a headtank 3 I, within which is located a stirrer or paddle provided for the purpose of maintaining the mix in a homogeneous condition.

r is fed outwardly and caught in a pail 33 carried. The pulp at this stage has a known The'mix is fed down from the head tank to an expeller 32, through which the pulp isfed and a predetermined portion of the water expelled by compression in a manner well understood in the art. From the expeller the partially dried pulp by a truck 34. water content which is important in the securing of uniformity in the mix procured as the result of subsequent operations.

The mechanisms heretofore described are of standard construction and of a character commonly employed in the paper making or other allied arts, so that a detailed description of each of said mechanism is not required.

The charge of material in the pail 33 is elevated by a cable 35 to an upper elevation in the building, wherein are located a pair of mixing tanks 38, which are duplicates, each 0! which is provided with a discharge pipe at leading to a common discharge pipe The arrangement is one which enables the operator to employ the mining tanks alternately hy mng up a mix of. material in one of the seen while the other is discharging, so that a continuous new of properly mixed material can be constantly maintained.

the valvestem to be raised and lowered to seat or unseat the plug valve to as occasion may re- The valve stem I I is surrounded by a tubular shaft 46 which is carried by the hub 41 of a bevel ear 58. The tubular shaft is iournalled through a journal block 49 in the center of a bridge plate or spider bll which spans the upper rim of the tank;

The tubular shaft is provided with paddles or beater bars 5!, and the outer end of the lowermost beater bar 52 is upturned to lie in closely adjacent relation to the conical hopper bottom and serve as a scraper bar for preventing the material from adhering to the walls of the tank.

. 'Th'e fibrous material is discharged from the pail into the tank which is under replenishment for the time being, and as the properly measured quantity 0! material is being poured into the tank, a liquid solution whichconsists mainly of water with a charge of saponin supplied, thereto,

as a foaming agent is discharged through apipe 53, each of the tanks being supplied with one of such pipes, which unite in a three-way valve casing 54 and connect with a header 'pipe 55 lead- Sng'to a meter 56 having a supply pipe 51, through.

which the solution of water and saponin is'admitted in measured quantities to unite with a measured quantity or flbrous-material'ofknown liquid content, so that by properly measuring out the amounts of fibrous material andsapon'in solution, a mix of predetermined liquid content will be admitted to the tank and subjected to a.

' mixing or stirring action throughout the period of time required for the discharge of previously mixed "material from the companion tank, with the result that a proper mix will be maintained at all times, which is highly essential in securing uniformity in'the density and thickness of the completed layer of distended fibrous material.

The mix, after being discharged through one of the pipes 31 and through the common discharge pipe enters a cylindrical measuring valve casing 58, within which is located a shaft E9 carrying radially extending wings or plates 0, four being shown in the present embodiment.

wall 6| which lies in closely adjacent relation to the surrounding wall of the casing, so that a pair of radial wings. or plates 60 with the connect-- ing curving wall 6| constitute in effect a segment, and between the two segments thus formed are located open cavities 62 which constitute the pockets for the reception of charges of the mix, which by rotation' of the shaft 59 are carried around to the lower side of the valve chamber and discharged through a discharge pipe 63 located above the first compartment of an agitator tank 84 presently to be described.

Elie ends of the pockets 62 in the measuring valve member are closed by head walls as which rotate within recesses tit in head plates ti constituting part of the valve casing, and in order to Adjoining plates are united by a curving outer afford. asharp cutting edge for shearing the fi-' brous material, the leading wing or plate of each segment pair is provided with a cutting blade 3t 7 which coacts with a cutting blade 69 located at the shoulder formed by the emergence of the T from end to end of the rotating valve, and the throat Hi likewise extends from end to end of the valve casing, with the pipe 38 centrally located to discharge into the chamber thus afiorded in thethroat, which permits the liquid and fiber to distribute itself equally from end to end or the casing and to flow down into whichever oi the measuring pockets is moving through the upper portion oiits rotation for the time being.

In order to allow air to be vented as the mix flows into the pocket, a vent plug II is provided at a point closely adjacent the throat ill, so that, as the'measuring valve rotates and the material is delivered into the upwardly presented pocket,

the air will be ejected, permitting the pocket to fill upto the top, without cavities or open interstices therein, so that, when the charge is cut oil by the shearing action of the knife blades, a measured charge of predetermined amount will be carried downwardly to the discharging position.

The measuring valve is rotated by the mechanismshown in Fig. 8. This consists of a ratchet wheel 12 keyed upon the shaft 59, which ratchet wheel cooperates with a" dog 13 carried between an outer lever arm '14 and an' inner arm 15 connected bythe shoulder 16 with the. lever arm. The arms I4 and 15 are pivoted upon shouldered which arms'in unison are pivoted to the buter ends of links 18, the inner ends of which straddle an adjusting screw block 19 on an adjusting screw Oil journalled through a standard 8| and operable by a hand wheel 82. fflie links 18'cooperate with lowerlinks 83 pivoted upon the lug 84.

The arms "support between them an arouate shield 85 which overlies the teeth on the ,hubs 'I'l freely mounted upon the shaft 59, each of the hubs being provided with any arm H desired degree. In Fig. 8, the position assumed by the arm H at the end of its thrust to the right is indicated in dotted lines, from which it will be observed that the shield 85 in the position shown serves to out ch four of the teeth, and

to "that extent reduces the range of movement of the measuring valve upon each operation of the ratchet. The arm '14 is actuated by a link 86 (Fig. 2) which connects with a rocking arm 81 actuated by a star wheel 88, which in turn is rotated by worm gearing 89 driven by a motor 90. Any other suitable mechanism for imparting oscillations to the arm 14 might be employed, but by adjusting the effective range of action of the dog 13 in the manner shown, it is possible to closely regulate the feeding speed of the measuring valve so that the material will be delivered to the tank 64 in uniform relation to its discharge onto the wire of the Fourdrinier machine.

The tank 64 in the form shown consists of an upper section 9|, and a lower section 92, ar-

ranged in superposed relation and connected through a duct 93. This arrangement is desirable in that it conserves floor space, although the same result would be obtained by an arrangement in which the two sections were aligned with one another or merged into a. single tank of corresponding length.

,In Fig. 3, the center portions of the tank sections are broken away,.but as indicated in Fig. 2, the lower tank section comprises ten compartments, and the upper section four compartments, which are separated from one another by weirs 94, which as shown are of progressively reduced height from the intake end toward the discharge end of each tank section. Each of the compartments thus formed is providedwith a group of stirrers, each in the form of upper andlower paddles 95, and 96 mounted upon a vertical shaft 91. -The upper and lower paddles stand in vertically spaced relation to one another, the spacing being greater in the deeper compartments and correspondingly less as the depth of the compartments decreases toward the discharge end of the tank section. The lowermost paddles, however,

stand at a uniform height above the floor of the tank.

The four shafts for actuating a single group of stirrers stand vertically in parallel aligned relation from side to side of the tank compartment within which they are located, and the shafts are journalled through bridge bars 98, and are also provided with pulleys 99 and belts so arranged that all of the shafts will be operated in unison. As shown in Fig. 1, power is imparted to the outermost shafts at one end of adjoining groups through power belts IOI operated by ajdriving pulley I02, which drives the v outermost shafts of adjoining groups, and the power thus imparted is distributed to the next w .of power. '7

od of driving, however, is immaterial so long as provision is made for the uniform rotation of all of -the'- stirrers in unison from a common source Each of the paddles is provided with blades I04 which extend outwardly and terminate in rearwardly extending downturned wings l05,the arrangement being such as to produce a vortical motion within the liquid mix, which tends to draw the material toward the centenalthough constantly permitting the escape of some of the materialover the lower weir and toward the discharge end of the tank.

The mix of materials is discharged fromfthe 'mixing valve into the bottom of. the firstcompartment in the upper tier. The last compartment in the upper tier on the discharge side is provided with a wall I06 above which E located a fiap valve I01 mounted on a shaft I08 operated by a handle through a worm and gear arrangement I09, which enables the fiap'valve .to be elevated to afford the desired clearance above the wall I06.

The duct 93 discharges beneath the lower edge of thew'all I06 and into the first compartment of the lower tier. The last compartment of the lower tier is provided with a curving bottomplate H0 which extends from the crest of the last weir downwardly'and forwardly and terminates in a lip III which contacts the surface of the wirelI2 on the Fourdrinier machine, thus furvided with an adjustable face plate H9 which permits the clearance to be further regulated. Af er the layer of material has been flowed onto the wire of the Fourdrinier machine, it is confined in the form of a straight edged layer between deckle strips -l20, and as the wire advances, this layer is subjected to the suction of vacuum boxes I2I and finally delivered across atransfer belt I22 into an oven I23, where it is subjected to a drying process prior to its ultimate delivery and severance into sections of the desired length. These operations are described in the Bryant Patent No.'1,841,785, and need not be here described in complete detail.

The mix thus measured out flows into the first compartment of the upper series and fills the compartment to the level of the weir. .The stirrers, being operated in unison throughout the different compartments, will cause rotation of the upper and lower paddles which impart a vortical movement tothe liquid inflowing into each of the compartments in turn, and the movement thus imparted tends to draw the liquid mix toward the center of the vortex, but as the liquid rises to the level of theweir, a portion thereof will escape into the next compartment, so that,

as the compartments become filled, there will be a constant overflowing of the weirs, at .a descend ing level, however, in each section of the tank, a portion of the liquid escaping over the weir and the remainder beingdrawn back into the vortex, so that the material in each-compartment will be repeatedly recirculated before a portion thereof overflows and escapes, and this operation will continue throughout the upper and lower sections of the tank, thereby thoroughly agitating and foaming the liquid mix and causing a thorough diffusion and distention of the fibrous particles which are held in distended relation by the minute bubbles composing the foam. so that by the time the mix reaches the point of final discharge onto the wire of the Fourdrinier machine a uniform stream of material may be maintained at'the point of discharge anddeposited upon the wire of the Fourdrinier machine in the form of a layer of uniform depth and-uniform con sistency. The layer thus deposited at the wet end of the wire will be confined between the deckle strlps'and advanced by the Fourdrinier wire, which permits a portion-of the liquid to drain away and a portion thereof to be extracted by suction, which also has the effect of forming upon the surface a relatively thin tough paperlike skin, which in the completed product serves to maintain the sections in a relatively stifi and coherent condition, so that they may be ultimately cut tothe desired size for the intended By the employment of pulp of the desired character, and byu'egulating the fluidity of the same and the extent of the agitation to which it is subjected and the amount of the foaming agent employed, it is possible, within 'wide limits, to vary the'quality and character .of the resulting product, including the degree of distention ofthe fibrous particles, and the softness or flufiiness of the product. It is thus possible to produce distended fibrous materials of sumcient softness, fineness and distention to serve in hospital use, or for sanitary purposes, or to vary the treatment in such a way as to secure a product of the, requisite firmness and stiffness to serve as an insulating layer in buildings, refrigerating appliances, or under like conditions where an insulating layer is required.

Although the method has been described with considerable detail, it is not the intention,,un-'

less otherwise indicated in the claims, to limit the claims to the precise method described, since modifications in detail maybe introduced without departing from the spirit of the invention.

taining contiguous pools of liquid mix having their surfaces zit-progressively lowerv levels, supplying measured quantities of fiber and liquid including a foaming agent to the first pool'of the series in the amounts required to provide a mix of the desired consistency, constantly maintaining individual agitation in each of the pools to the extent required to cause foaming of the mixture and to separate and maintain the fibers indistended relation within the. foamy mass, (118- charging. from each pool by overflow to the sur- 2,105,711 I My face of the next pool in the form of a broad even layer and discharging from the last poolof the a series in the form of'a broad even continuously form width and thickness, which consists in maintaining contiguous pools of liquid mix having their surfaces at progressively lower levels, supplying automatically measured quantities of fiber foamy condition. and to separate and,maintain the fibers in distended relation within the foamy mass, discharging from each pool by overflow to the surface of the next pool in the form of a broad even layer and discharging from the last pool of the series in the form of a broad even continuously horizontally advancing layer of uniform thickness, confining the sides of the advancing layer to maintain a uniform width for the layer, and extracting liquid from the layer during its advancement to the extent necessary to make the layer self-sustaining and capable of manipulation.

3. The method of producing a coherent layer of distended fibrous material of substantially uniform width and thickness, which consists in maintaining contiguous pools of liquid mix having their surfaces at progressively lower levels, providing difl'erent sources of supply for measured quantities of fiber and liquid including a foaming agent combined in the amounts required to provide a mix of the desired consistency, delivering charges of said mix alternately from each of said sources-to the first pool of the series and constantly maintaining individual vortical agitation ineach of the pools to the extent required to cause foaming of the mix and to separate and maintain the fibers in distended relation within the foamy-mass, discharging from each pool by overflow to the surface of the next pool in the form of a broad even layer and discharging from the last pool of the series in the form of a broad even form thickness, confining the sides of-the advancing layer to maintain a uniform width for the layer, and extracting liquid from the layer during its advancement to'the extent necessary to make the layer self-sustaining and capable of manipulation. V

, GEORGE C. WEA'I'HERED.

continuously horizontally advancing layer of uni-'

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