US2646381A

US2646381A - Method for dispersing and felting fibers and mill

Info

Publication number: US2646381A
Application number: US130549A
Authority: US
Inventors: Thure C Duvall
Original assignee: Wood Conversion Co
Current assignee: Wood Conversion Co
Priority date: 1949-12-01
Filing date: 1949-12-01
Publication date: 1953-07-21
Anticipated expiration: 1970-07-21

Description

, July 21, 1953 v T. c. DuvALL METHOD FOR DISPERSING AND FELTING FIBERS -AND MILL Filed Da ac.. l, 1949 4 Sheets-Sheet 1 .if afweg/ July 21, 1953 r. c. DuvALL METHOD FOR DISPERSING AND FELTING FIBERS AND MILL Filed Dec. l, 1949 4 Sheets-Sheet 2 Ware C.' uva/ yg/(f July 21, 1953 Filed Dec. 1, 1949 T. C. DUVALL METHOD FOR DISPERSING AND FELTING FIBERS AND MILL 4 Sheets-Sheet 3 llllll I?? We?? for 77g are zeval July 21, 1953 T. c. DUVALL 2,646,381

METHOD FQRHDISPERSING ANU' FELTING FlBERS AND MILL u? for?? ey lPatented July 2l, 1953 METHOD FOR DISPERSING ND FELTING FIBERS AND MILL Thure C. Duvall, Cloquet, Minn., assigner to Wood Conversion Company, St. Paul, Minn., a corporation of Delaware Application December 1, 1949, Serial No. 130,549

12 Claims. (Cl. 154-101) The present invention relates to the individulization of thevegetable fibers for dispersal in air', and in particular to apparatus for such practice, and to utilization of such suspensions.

In the formation of ber mats by deposition of fibers from suspension in air, as by gravity deposition, or byfpressure felting, or by suction felting, there are diiiiculties in keeping the fibers in individualized condition against flocking. In some cases it is'common practice to apply liquid adhesive to the fibers by injecting into the dispersed fibers a mist or'spray of liquid which is or which contains the binder or adhesive. It is most desirable that all of the fibers be exposed to the spray so that all receive binder. When fibers are present in flocks or clots before receiving binder, the desired application of binder isnot achieved. In particular, wetted clots de-V posit as such or in larger flock-form, and 'nonuniform mats of poor quality' are the result on drying the deposited mat, With or without com-Y pression before drying. Hence, it is important to expose individualized bers in the path of the binder spray. l

Sometimes powder binder is introduced so that it falls with the bers in forming a dry liber mat. It is equally important that clots bemin'- imized so that a uniform deposition of liber Vresults, with auniform distribution of solid binder when the latter is used.

In commercial production of mats in the man- Y gli cylindrical face and aconcentric rotor to effect passage of fibers through said face.- This is commonly in the form of a cylinder vcontaining an axial rotor with swinging radial hammers, 'the ends of which just clear the inner periphery of the cylinder. AThe cylinder is perforated With holes, or is provided as a suitable screen, providing, for example, openings of about 3% inch diameter when the liber is Wood liber. Where only a portion of the'cylinder is so perforated,

the remaining portion of the inner periphery may have obstacles, such as ribs positioned as Vgeometrical elements of the cylinder, against which thel radial hammers rub clots to effect disintegration. This same action Vtakes place v also at the edges of the perforations.

invention.

ners described, it is necessary that ber be introduced-at a rapid rate, and since the fiber is preferably carried in suspension in air, it is a ,commercial objective tovminimize the quantity of air moved, and maximize the concentrationrof bers in the air. y

kExperience has shown that the higher the concentration of individualized fibersfin air, thev more they tend to clot; and also that the tend- Itis a general object of the invention to minimize clot-formation in providing. a continuous stream of air having a high concentration of individualized easy-felting fibers `which are thereafter felted into a mat of highly uniform quality.

. It is a particular object of the present inven tion toprovide apparatus for the individualizing and discharging as above referred to, for injecting at high velocity a stream of air carrying a f high concentration of individualized fibers into ency to clot is increased by the presence of surfaces on which the air-suspension of fibers may impinge.

In actual practice in formation of mats by deposition from air suspensions of individualized fibers, it has developed that a nal indi-Q vidualization step should be practiced as vnear as practicable to the point of dispersal of the fibers for deposition. This eliminates the clot formation which otherwise takes place in con`-l duits, and it breaks up the clots so formed in bringing air'containing ber to the iinal'disperser by way of conduits. Y 1

As aV nal disperser, or individualizer, there Vand Well along the length of a dispersal and -deposition chamber, with the substantial avoidance of clotting after nal indiviclualization.v

It is a -particular object-of the invention to Y provide a-combination'of hammer-mill disintegrator and a discharge nozzle therefor which avoidsV clotting of individualized fibers passing therethrough.

VThe invention will be best understood from the Aillustrations in the accompanying drawings in` i which:

` principle involved.

Fig.V '3- is a vertical'cross-section of the diss used a type 0f apparatus having ya perforated perser and nozzle taken normally to the axis.

Fig. 4 is a vertical cross-section of the disperser taken on line 4-4 of Fig. 3.

Fig. 5 is a plan view of the spout portion of the nozzle, showing a slight taper.

Fig. 6 is a more or less diagrammatic representation of the device with its nozzle discharging into a ieitingspace between two parallel conveyer screens through which the air escapes and between Which a fiber mat is formed.

Fig. 7 represents another use of the fiber discharging device directing an expanding stream onto a moving screen to which suction is applied, and in such manner that air employed in the process is recirculated.

It is to be understood that the present invention may be used in other ways than those illustrated. The primary purpose is to form a continuous stream at high concentration of individualized bers for many uses to which such a stream may be subjected. Since the primary objective of the applicant is to produce homogeneous felts from air suspensions of the fibers, the present application illustrates several Ways in which the nozzle may discharge its stream for felting.

In the practices where liquid adhesive is applied to individualized fibers, the application is commonly eiiected in a settling chamber rather than in a conduit or other constricted channel which would iinally become obstructed by adhesive accumulation of bers on its walls. In a large settling chamber this danger is minimized or otherwise it is easily compensated for.

Where adhesive is not employed and the fibers in the stream are dry, more constricted felting regions may be employed. In the present application two such cases are illustrated. In one the bers are ejected into a space which is substantially a continuation of the space Within the nozzle so that the stream of bers is not expanded, but the stream of air is expanded by reason of passage through filtering screens against which the bers felt.

In the second case herein illustrated, the air and fiber streams are but slightly expanded, as in a region over a conveyer screen through'which the air escapes and on which the bers mat. The screen may have suction to enhance the differential pressure at the felting area of the screen, and theV suction may be arranged to recirculate the air passing through the screen so that it is replenished with brous material.

In Fig. l a large chamber, for example feet long by lo feet in height, and of any desired width, such as l0 feet, is formed by side Walls Il,

end walls l2 and I3, a ceiling lli, suitably vented as at i5, and a ioor which is an endless conveyer I1 running over end roll i8. The conveyer l1 is preferably in the form of a Wire screen, in part for the purpose of minimizing its actual top surface to which the formed mat may adhere, in part for additional venting, and also for mechanical reasons.

The numeral 20 designates a disperser in the form oi a hammer mill, and the dotted line 2| represents an exemplary extent of the mill periphery which is perforated to discharge bers. The conduit 22 delivers into the mill an air current carrying iibers and fibrous material coming initially from a primary disintegrator 23 Vof any suitable kind.

Disintegrator 23 may be a hammer mill into which is fed fibrous material, such as pulp sheets or laps or pieces thereof designated 24. The disintegrated product as formed is a ui which is 4 not guarded against clotting on its way to the disperser 2i) by way of hopper 2i connected to conduit 22. The mill Zi provides suction to draw air and iiber into the hopper.

Because of the length of chamber Iii into and along which the fiber is to be dispersed, a suitable nozzle is required on the k'dispenser Zitto" inject the air-suspension of fibers at a sufficiently high speed to carry into the chamber, for dispersal as stream F, into which is mixed a mist A of adhesive-carrying liquid.

In preferred practice, the invention sacrices some capacity for additional discharge pressure,

lby employing about of the periphery of the structure and its relation to the final disperser.

However, it must be rst explained that the invention pertaining to the nozzle may have many embodiments adaptingY it for use with many conventional types of mills. Some dispersing mills have the entire periphery open as the perforated area throughvvhich to discharge. Other vmills have only a vfraction of the periphery so perforated. The function of the vmill is not changed by these characteristics, but its operating performance and capacity are thus subject to modiiication.

A very small area of perforationgives limited capacity, but it may give higher discharge pressures. An entirely perforated periphery gives larger capacity, but lower operating discharge pressure. Fig. 2 illustrates more or less diagrammatically, a hammerv mill having a periphery 28 and a rotor 2Q. Theperi-phery 28 is perforated around the entire circumference.

According to the present' invention, a nozzle structure in such a mill has aspout portion 39 and a housing portionv 3l encompassing the Ydischarge varea ofthe mill, in this case the entire periphery. Between -the walls of the housing portion 3i Vand the cylindrical wall of the mill there are

conveyance spaces

32 and 33 Vleading from the perforations to the discharge orice 30. It is a characteristic of the present invention that the portion of the periphery most distant from the discharge orifice along the line of each conveyance space is narrowest and that the conveyance space flares outwardly from the remote region giving a constantly enlarging and streamlined space donned by smoothly curved walls of the nozzle housing 3l and cylindrical outer wall portions of the mill housing 2S. Thus, the two spaces together are crescent-like or forked. in

cross-section and Where the tips of the horns or branches of the forkV come together, as illustrat-ed in Fig. 2, there is a dividing partition designated 3. The function of this partition is to prevent a secondary circulating current of air around the discharge periphery of the mill. Although there are two

channels

32 and 33 which enlarge in cross-section, the cross-section of the stream entering each channel is in fact gradually reduced yfrom the semi-cylindrical area of the mill to half the area of the opening of nozzle 3&3.

In the drawings in Fig. 3 the mill casing is in the form of a cylinder comprising the perforate or screen portion lie, a smooth section ril, a bar-section 42 having disintegrating ribs 43, and another smooth section d. Outside of the screen portion lit is a housing i which fits over the perforations. The mill parts 4l, Li, ze and housing i5 have radial flanges Ma, 32s,

Maand 45a, all suitably secured together by Vtween disks 84e.

flanges 45a and the retainers 49 for removably i mounting it and for readily replacing it. y

The arcuate extent of the screen may vary widely as described. As shown it covers about 107. The rib-portion 42 also covers about 1 0'1". Y

' bythe action of the rotor.

The housing has an end plate 50 through whichr passes a rotor axle 5I, to an outside bearing 52.

The opposite end of the-housing has a conical extension 53 housing mechanism functioning largely to facilitate distribution of material into the mill. An end plate 54 has an opening therein connected to an intake pipe 55, which is the pipe 22 in Fig. 1.V The axle 5I extends through end wall 54 and through a bearing 55 where its end carriesv a friction driving pulley 51 for multiple V-belts.

The rotor has a sort of squirrel-cage cylinder structure of which. the cage-barsY are pivots for the swinging hammers. The rotor axle 5I is keyed to end plates 59 and 60 which carry between them at equal arcuate distances near their peripheries tie bolts 6| forming the bars of the squirrel-cage structure. rEhe tie bolts Glare axles on which are suspended a multiplicity-of bladelike hammers generally designated by the numeral 62.V The hammers are spaced apart by spacing collars 63 around the tie bolts 6l, and also by spacing disks 64 'disposed in spaced relation between the side plates 59 and 60, these spacing disks serving to Vresist the outward pull on the tie bolts as the result ofthe centrifugal force extension 61 may be mounted a' substantially' straight length of circular pipe, for example, up to 8 feet in'length as the discharge nozzle.

In operation the conduit 55 functions as a suction conduit by reason of the windage produced The suction draws in the fluffy clotted fibrous materialV fed to it from theA primary dispenser 23. With constant speed of operation of the'rotor the supplyofair and liber brought `to the' mill is substantially constant. The rotor acts to create a pressure',

which discharges through the spout 65 carrying with it the individualized bersresulting from the rotorl rubbing the fluff and clots around the interior, the discharge taking place through the screen 40. By reason of the crescent-"form of the space within the nozzle housing, the airl sus.- pension is stream-lined, and the streamldoes not impinge on wall'obstructions in such manner as again toV induce clotting. As a result, the;

nozzle .dischargesbers free from clots and at character described suiice to give uniform dispersion vand deposition across the width of the chamber.

Referring to the crescent-shaped space to' which the discharge spout is connected, it is exerted by the multiple hammers 52 at high speeds of the rotor, for example, 1750 R. P. M.,with a radialdistance of approximately 18 inches to-the ends of the hammers. Later-ally of the hammers 62 which move over the perforate cylindrical pora l tion 40, thereis a secondary portion having blades 62a with a slight twist to act asA impellers for knocking material entering the machine through conduit 55A into the mill proper.' Thel twisted blades also act as fan blades to supplement the main blower action of the primary hammers 62.k The blades B22/swing on vbolts 6ia mounted beu The rotor'also carries radial striking bars B2b which serve to breakup large clumps'or bodies-of fibrous material entering the mill, these bars passing the discharge oriceof conduit 55. v v Y Ihe nozzle housing which is secured outside and over the screen 4 of the mill as shown in Fig. 3, in( cross-section forms a crescent-like space over the screen with its two horns aring away from a spout. structure 65.

The smoothly curved inner Vwalls of the housing 45 also curve into parallel horizontal top and bottom walls ofv the spout, which is substantially 8 inches high clear Vthat the space increases in cross-section from each horn tc the spout. But, since rthe smaller arc ofthe crescent is perforate, and is the source of a stream of air leaving the cylindrical housing of the mill, it follows that lthe crescent chamber serves to reduce the lcross-sectional area of the stream leaving the perforateV v This. effects an increase in velocity of'the'ber- I airl streamas it leaves the perforate area and for thevsize of rotor described.- The spout is so formed on its sides that it tapers slightly'v to a squared opening, andthe squared opening is then extended by a short Ystraightilength of conduit 61, approximatelyA 10 inches long, said extension changing in cross-section from, the,

squared'opening at its union withthe spout 55 to its terminal circular discharge end 68.- The spout 65 extending from the housing 45 has respectively top and

bottom walls

69 and 10, Withside wallsVV 'll-and 12 all terminating in a flange structure 13 around a square opening, to which the extension 61 is connected kby its flange 14. Onto the thus the vsuspended fibers tend to movev apart.v

Y ing of the bers. As a result, the mat deposited n has a very low density.v Nevertheless the device maybe employed inprocesses wherein pneumaticv forces assist in depositing the fiber in felt forma.-

tnion,sck)`a'sl to'control the impact of bers on striking, and thus to increase the density of 'the initial felt as the impact increases. l y

In Fig. 6 the numeral 1liv represents aA hammermill of the kind described, equipped with a crescent-likey collector 1| connected to the straight nozzle 12.` The nozzle 12 discharges its stream `of fiber 13into a rectangular space between two Y parallelfendlessvscreens 15 atthe top and 161at *being*present,` but not disclosed.

theY bottom, sui`table side walls between them The upper Vscreen. 15 runs over a roll 11iy just above the nozzle 12,-and over another roll 18 at theopposite end fl The Aconveyor 15 is longer than theY conveyor 15`so that operations maybe performed on the bat,19 carried. thereby and .discharged therefrom. Theuv'screen.16fpasses overa roll 8l on the underside of; the nozzle 12, and at thev other'en'd passes over a roll 82. Suitable mechanism; gnotshown) is provided to move thependless screens 15 and V'[6 lat the samev linear rate awai7 from the upperand/lower edges oil thenozzle 12,1-thereby tojformbetweenthem'the'bat 10. The bat is formed by the screens filtering the bers from the air which escapes throughthescreens andl into vcollecting boxes 84 and85, respectively, above the felting stretch of-,the screen Y1-5 Aand belowthefeltingstretch of thescreen -1-6. These boxes serveto collectanynes of materialfwhich may.gothrodghthescreen and the :air from the boxes isexhausted through the conduits 86 and 81.

The conduit 86 and 81 may be so lconnected into the stream which feedsairto Athehammermill 10 by way of itsinletS, that -the -iines are recirculated and captured on recirculation by the bat `19. This recirculation may be accomplished invseveral ways, andin connection with another type of felting, vsuch ;a recirculation system is indicated in Fig. '1.

Fig. 7 `represents felting on la'screenvby diierential pressure resulting from discharging the individualized fibers at super-atmospheric pressure onto afelting screen, the underside of which is subjected to sub-atmospheric pressure. This necessitates a, condition of atmospheric pressure at the felting area of the screen, thus permitting the ielting to be effected -on the screen yat atmospheric ypressure without the requirement for enclosing walls or afhood. By the expedient for providing the greater capacity at the suction side,

the screen-may be made to draw` in air from the atmospheraas Willbeclear with reference to the description below.

First Athere is asupply lcof'brous material, such as pulp sheets, laps, or Vwood chips, fed to ar rener 4|'|l| .which converts it to deiiberized form suitable for felting When :adequately dispersed for .such action. Fiber lin -dry form is represented .as .a supply |02, -irom whicha feed control |03 delivers it -to an endless feed belt |04 carrying it into a hopper opening |05 in a suction conduit |06. The suction conduit |06 leadsto a blower |01, which in operation--disperses the ber into a fast moving stream kin a conduit |08 leading .to a cylindrical dispersing mill |079 of the type alreadydescribed Yand-having therein a rotor with `hammers The mill .|09

haga nozzle `crescent ||;2 and-a spout H3 theref or of the character' previously described, so located on the mill as to direct a stream of individualized fibers 4 downwardly ,toward an endless feltingscreen Y| I5.

Under the Screen l l `and vbelow .the discharging spout |.3 is asuction box 6 Iconnected -to the suction end of a `blower gl I1 for handling a greater volume o f air .than the blower |01, and hence drawing in air from the atmosphere about the stream of fibers I4.

In operation, a dispersion of ber is continuously formed and discharged from the dispersion mill |09 under highly favorable conditions for uniformly felting it to a dry felted sheet, which may be three to four inches in thickness as indicated at |3|, as carried away from its place Yof formation. It may be densirled as by compression rolls |32 and |33, the latter being under the screen and supporting the return stretch of the screen, which, -howeven-makes a shorter turn over idler roll |34. Adjacent the idler roll |34 is a pick-up roll |35 which carries the compressed felt |36 to a conveyor belt |31 passing over adjacent idler |38.

From theforegoing it is to be understood that the invention broadly provides a continuous stream of individualized bers at high concentration in air or other gas, for Various uses, primarily felting into mats or bats at a high rate of production with resulting high quality in formation because of the tendencies to minimize clotting of the fibers.

Numerous adaptations of the process and modications and changes of the apparatus may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. A dispersion mill for'discharging substantially individualized iibers in suspension in argas, comprising a cylindrical housing, a rotor substantially coaxial with the housing, said housing being imperforate over approximately threequarters portion of its arcuate extent and perforate over the remaining portion for the discharge of a gaseous stream from within the housing, said perforate portion having small holes for effecting individualization of fibers into said stream in operation of the mill, and collecting means over said perforate portion forming a chamber having in cross-section a crescent-like form, said means intermediate the ends of the crescent-like chamber being extended in a direction substantially radial to the rotor axis as a dischargenozzle.

2. A nozzle-bearing dispersion mill for discharging an air-suspension of substantially individualized bers comprising a cylindrical mill housing having discharge perforations over approximately a quarter portion of its periphery for the discharge of a gaseous stream from Within the housing, a nozzle housing mounted on said mill housing, a discharge spout carried by the nozzle housing and extending in a direction generally radial to said mill housing, said nozzle housing providing forked conveyance passageways for discharging said stream from the perforated area of the mill housing to said spout, said passageways together forming an open crescent in cross-section with horns tapering inwardly of the nozzle housing from the spout and being deiined Y f. by smoothly curved inner walls of the nozzle housing, said cylindrical outer wall portions of the mill housing.

3. The method which comprises ydistributing substantially individualized bers into a moving stream of air over a fiber-distributing ,area extending substantially crosswise of the stream, collecting the ber-laden air moving from said area and conducting it to a discharge nozzle of substantially uniform cross-sectional area and simultaneously increasing the velocity of the berpoint of discharge from said nozzle, whereby toA lessen the velocity-of the moving bers and thereby on the average further separating each ber from the other bers. Y

4. Themethod which comprises distributing substantially individualized bers intov a moving stream of air over a ber-distributing Varea. ex-

tending substantially cross-wise of the stream,

collecting the ber-laden air moving from said areav and conducting it to a discharge nozzle of .substantially uniform -cross-sectionalarea and simultaneously increasing the'y velocity of the ber-laden air on all the lines of travel from said area to said nozzle by gradually constricting the cross-section of the stream as it moves from in a generally horizontal direction into asettling Y said area to said nozzle, whereby theiincreased velocity minimizes tendencies of the fibers to clot,

"discharging the ber-ladenstream from said nozzle and simultaneously expanding said stream yat the point of discharge from said nozzle, whereby to Ylessen the velocity of the moving bers and thereby on the average further separating each berV from the other bers, and collecting and felting the separated bers in the'form of a felted ber body.

5. The method 'which comprises distributing substantially individualized bers into a moving stream of airv over a ber-distributing area exf:

tending substantially.crosswisefbf the stream, collecting the ber-laden air moving from said area and conducting it to amdischarge nozzle offsubstantially uniform crossfs'ectional area and simultaneously increasing'the velocity ofthe berf, laden air on allv the linesn of travel from said` area to said nozzle by graduallyconstricting the crosssectiony of the stream as it moves from said area to said nozzle, whereby the increased velocity minimizes tendencies of the bers to clot, dis.`

charging the Aber-laden stream from said nozzle and simultaneously expanding saidV stream at thepoint of discharge from said nozzle, whereby to lessen the velocity of the moving fibers and thereby on the averagefurther separatingeach ber from the other bers, and collecting andr feltingthe separated bers in the form of a felted yber body by allowing the bers to settle'by Y gravity onto a collecting area. I

6. The method whichvcomprisesV distributing substantially individualized bers into a moving streamof air over a ber-distributing area ex' tending substantially crosswise of the stream,

collecting the ber-laden air moving from said area and conducting itvto a discharge nozzle of substantially uniform cross-sectional area and simultaneously increasing the velocity of the ber-laden air on all the lines of travel from said area to'said nozzle by gradually constrictingthe cross-section of the stream as it moves from said area to said nozzle, whereby the increased velocity minimizes tendencies of the e bers to clot, discharging theber-laden stream from said nozzle in a generally horizontal direc-w V,tion into a settling chamberand simultaneously ity of the moving bers and 'thereby Von the average further separating each ber from the other bers, and collecting and feltingthe separated l0 bers in the form of a felted ber bodyeby allowing the bers to settle by-gravity onto a collecting area.

7. The y method which comprises distributing substantially individualized bers into a moving stream of air over a ber-distributing area extending substantially crosswise of the stream, collecting the ber-laden air moving yfrom said area and conducting it to a discharge nozzle of substantially uniform cross-sectional area and simultaneously rincreasing the velocity of the ber-laden air on al1 the lines of travel from said area to said nozzle by gradually constricting the cross-section of the stream as it moves from said area to said nozzle, whereby the increased velocity minimizes tendencies of the bers toclot, discharging the ber-laden stream from said nozzle chamber and simultaneously expanding said stream at the point of discharge from said nozzle, whereby to lessen the velocity of the moving bers and thereby on the average Yfurther separating each ber from the other bers, and collecting and felting the separated bers in the form of arfelted ber body by allowing the bers to settle by gravity onto a conveyer'moving across the bottom .of said settling chamber.

8. The method which comprises distributing substantially individualizedbersinto a moving ber-laden air on all the lines `of travel from said area to said nozzle by gradually constricting thefcross-section of the stream as it moves from said areato said nozzle, whereby the increased velocity minimizes tendencies of the bers to clot, discharging Ythe ber-laden stream from to settle by gravity'onto a collecting area, anddrying the resulting felted body to set the adhesive. I

9. Themethod which comprises distributingv substantially individualized bers'into a moving stream of air at superatmospheric pressure vover a ber-distributing area extending substantially crosswise of the stream, collecting the ber-laden air moving from said area and conducting it to a discharge nozzle of substantially uniform cross- 'sectional area and simultaneously increasing the velocity of the ber-laden air on all the lines of travel from said area to said nozzle by gradually constricting the cross-.section cf the stream as it moves from said area to said nozzle, whereby the increased velocity minimizes tendencies of the ber to clot, discharging the stream of berladen airrfrom said nozzle into a region of lower pressure whereby the stream expands, and collecting the individualized bers as a felt prior to any substantial clotting of the bers.

10. The method which comprises distributing'V substantially individualized bers into a moving stream of air lat superatmospheric pressure over a ber-distributing area extending substantially l 1 crosswise Vof the stream, collecting the fiber-laden air moving from saidarea and conducting` it to a discharge nozzle of substantially uniform crosssectional area and simultaneously increasingthe velocity of the fiber-laden air on all the lines of travel from said area to said lnozzle by gradually constricting the cross-section of the stream as it moves from said area to said nozzle, whereby the increased velocity minimizes tendencies of the fiber to clot, discharging the fiber-laden streamv into'a region of lower pressure and onto moving endless screening means and thereon forming a felt prior to any substantial clotting of the fibers.

11. The method which comprises distributing substantially individualized fibers into a movingstream of air at superatmospheric pressure over a ber-distributing area extending substantially crosswise of the stream, collecting the fiber-laden air moving from said areaandfconducting it to a discharge nozzle of substantiallyfuniform crossvelocity of the ber-ladenairf on all the lines of travel from said area to said nozzle by gradually constricting the cross-section of the stream as it moves from said area t said nozzle,- Whereby the increased velocity minimizes -tendenciesof the ber to clot, applying sub-atmospheric pressure tonne Yside of endless moving :screening-means, anddischargingthe berfladen stream-.from said nozzle onto. the resulting suction-area` ofv said screeningmeans prior to any,` substantialclotting of the ber, whereby to `form afelt on said screening means.

12. The methodwhich comprisesdistributing substantially individualized .bers intoa moving stream of air at superatrnospheric.. pressure over armer-distributing area extendingsubstantially crosswise of the streamrcollectingtm fiber-laden air moving from said area.. and conducting` it to a discharge nozzle of substantiallyuni-form'crosse sectionalarea and simultaneously increasing .the velocity ofthe ber-ladenair-.on .all theiines of sectional area and simultaneously increasing the travel from. said-,area `tofsaidsnozzle by gradually constricting the cross-sectionf thefstreamuas: it movesA fromsaid area to saidnozzle, ,whereby 'the increasedvelocity minimizes; tendencies ofv the fiber to clot, discharging.saiddibereladen stream from-said nozzleontoone face of movingendless screening. means prior to any substantial clotting ofthe bers, applying sub-atmosphericpressure tothe. otherside of said screening, meansY in a manner to draw in all the air from said nozzle and additional air from the atmosphere, whereby to form a felt on said screening means at a'lregion of '"tnei screen substantially at atmosphericf pressure.-

THURE C. DUVALL ReferencesV Cited in the lel of this `patent UNITED" STATES PATENTS Number NameV Datei 483,590 Waib'el Oct. 4, 1892 683,256 Druitt Sept. 24, 1901 978,034A Kinsey Dec.' 6, 1910 1,374,207' Jacobson' .Apr. 12, 1921 1,468,028I Maussner et al. Sept. 18, 1923 1,598,702 Bell Sept. 7, 1926 1,748,046 Bullock Feb. 18', 1930 1,786,669 l\l/Ianning.A Dec. 30, 1930 2,086,592 Williams July 13, 1937 2,125,993 Dellinger Aug.v 9, .1938 2,152,901 Manning Apr. 4,' 1939 2,193,263 Avery .Mar.` 12, 1940 2,309,326 Miller Jan.- 26, 1943 2,479,911 Delloye Aug. 23, 1949 FOREIGN PATENTS Number Country Date 422,226 Great Britain Jan. 8, 1935 425,271 Great Britain Mar. 11, 1935 608,252 Great Britain Sept. 13, 1948 889,625 France Oct. 11, 1943

Claims

8. THE METHOD WHICH COMPRISES DISTRIBUTING SUBSTANTIALLY INDIVIDUALIZED FIBERS INTO A MOVING STREAM OF AIR OVER A FIBER-DISTRIBUTING AREA EXTENDING SUBSTANTIALLY CROSSWISE OF THE STREAM, COLLECTING THE FIBER-LADEN AIR MOVING FROM SAID AREA AND CONDUCTING IT TO A DISCHARGE NOZZLE OF SUBSTANTIALLY UNIFORM CROSS-SECTIONAL AREA AND SIMULTANEOUSLY INCREASING THE VELOCITY OF THE FIBER-LADEN AIR ON ALL THE LINES OF TRAVEL FROM SAID AREA TO SAID NOZZLE BY GRADUALLY CONSTRICTING THE CROSS-SECTION OF THE STREAM AS IT MOVES FROM SAID AREA TO SAID NOZZLE, WHEREBY THE INCREASED VELOCITY MINIMIZES TENDENCIES OF THE FIBERS TO CLOT, DISCHARGING THE FIBER-LADEN STREAM FROM SAID NOZZLE AND SIMULTANEOUSLY EXPANDING SAID STREAM AT THE POINT OF DISCHARGE FROM SAID NOZZLE WHEREBY TO LESSEN THE VELOCITY OF THE MOVING FIBER FROM THE OTHER FIBERS, DISPERSING AN AQUEOUS MIST OF LIQUID CONTAINING ADHESIVE INTO THE SEPARATED FIBERS WHEREBY TO WET THE FIBERS WITH SAID ADHESIVE-CONTAINING LIQUID, COLLECTING AND FELTING THE WET ADHESIVE BEARING SEPARATED FIBERS IN THE FORM OF A FELTED FIBER BODY BY ALLOWING THE FIBERS TO SETTLE BY GAVITY ONTO A COLLECTING AREA, AND DRYING THE RESULTING FELTED BODY TO SET THE ADHESIVE.