US3086253A

US3086253A - Method and apparatus for producing fibrous batts

Info

Publication number: US3086253A
Application number: US646696A
Authority: US
Inventors: Curt G Joa
Original assignee: Falls Paper and Power Co
Current assignee: Falls Paper and Power Co
Priority date: 1957-02-14
Filing date: 1957-03-18
Publication date: 1963-04-23
Anticipated expiration: 1980-04-23
Also published as: GB884201A; GB884194A; GB884198A; US3016582A; GB884200A; GB884192A; GB884199A

Description

C. G. JOA

April 23, 1963 METHOD AND APPARATUS FOR PRODUCING FIBROUS BATTS Filed March 18, 1957 5 Sheets-Sheet 1 INVENTOR. Cum- 6-. Jan

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Arron/5Y5 April 23, 1963 c. G. JOA 3,086,253

METHOD AND APPARATUS FOR PRODUCING FIBROUS BAITS Filed March 18, 1957 5 Sheets-Sheet 2 [N V EN TOR.

C027 6-. Jan BY MAM MM A rramvsvi April 23, 1963 c. G. JOA 3,086,253

METHOD AND APPARATUS FOR PRODUCING FIBROUS BATTS Filed March 18, 1957 s Sheets-Sheet 3 INVENTOR. Cuer 6. Jo a April 23, 1963 c. G. JOA 3,086,253

.- METHOD AND APPARATUS FOR PRODUCING FIBROUS BAITS Filed March 18, 1957 5 Sheets-Sheet 4 INVENTOR. (war 6-. do?

A TfOE/VEY! A ril 23, 1963 c. G. JOA 3,086,253

7 METHOD AND APPARATUS FOR PRODUCING FIBROUS BATTS Filed March 18, 1957 5 Sheets-Sheet 5 INVENTOR. Cue?- 6. Jan

WIWrXr-M United States Patent cousin Filed Mar. 18, 1957, Ser. No. 646,696 16 Claims. (Cl. 19-156) This invention relates to a method and apparatus for producing fibrous batts. The present application is a continuation in part of my application Serial No. 550,653 filed December 2, 1955, now abandoned.

The batt may be formed from a wide variety of materials but will be described particularly with reference to virgin Wood pulp or reworked paper fiber, by way of exemplification of a class of fibrous material for which the invention is particularly suitable.

In one embodiment, the material is delivered pneumatically into an accumulator chamber. In another embodiment, preferred for most purposes, the material is disintegrated as in a hammer mill and the fiber is forcibly projected upon a vertical forming screen, belt, or apron. In both embodiments it is important that a forming screen be used which extends in a generally upright direction across the face of a vacuum box which holds the material to the screen as the screen moves.

In the path of the material held to the screen,.there is at least one and desirably two successive paddle wheels which perform differing functions. The paddle wheel first encountered by the material continuously removes surplus fiber from the face of the screen. Without something of the sort, the depth of material would depend on the pressure differential and the nature of the stock and would not necessarily have a constant value. Moreover, if the material were somewhat dense, the fiber on the surface, and therefore relatively remote from the screen, would not be acted upon by any very great pressure differential and would be very loosely held. The first paddle wheel not only levels the material but reduces it to a thickness such that all of the fiber of the deposit will be securely held by the available pressure differential.

This is important because the function of the next device to act on the material is to rearrange and level and comb the fiber, thereby tending not only to assure a uniform depth, but a uniform density and a reasonably uniform alignment of the fiber longitudinally of the-path of movement. For this latter function, a paddle Wheel or apron driven at relatively high speeds is the preferred mechanism. The function may be achieved in large part without any actual contact between the fiber rearranging device and the fiber, the rearrangement being achieved by air set in motion by the redistributing device. Material displaced by the air currents or the wiping or the combing or the brushing is accumulated in the bottom of the batt forming chamber and restored by a bottom conveyor to the forming screen or belt.

By the time the materialpasses the high speed redistributing device, it is sufficiently compact and uniform- 1y dense and of sufficiently uniform thickness for use and, moreover, it is sufliciently cohesive, by reason of the rearrangement and interlocking of the fibers, so that it will maintain its form during continued upward movement of the apron after the apron passes from the vacuum box. When the apron traverses the upper pulley over which it is trained, this material is guided for discharge from the chamber free of the apron. I may use a vacuum pulley to maintain continued vacuum on the apron and batt until the apron starts its return run and the batt is discharged.

The redistributing paddles or the reversely operating conveyors used in lieu thereof may be, and for some purposes desirably are, equipped with combing pegs or 7 3,086,253 Patented Apr. 23, 1963 ice teeth designed to comb through the pieces held by vacuum to the oppositely moving apron upon which the batt is formed. But for the fact that the pieces are still subject to vacuum when engaged by the combing teeth, they would be dislodged from the batt and the combing would tail of its purpose. By reason of the continued application of vacuum during the combing process, all the loose pieces are rearranged and their interlock is improved, while any knots or wads of fiber are either broken up or combed out, leaving the batt of more uniform thickness and density in consequence of the rearrangement of the remaining fibers. Such knots are small bundles of fiber as are not broken up may return repeatedly to the zone of interaction with the teeth and will ultimately disintegrate into the separate pieces desired.

Particularly Where the high speed reversely operating redistributing device is an apron, it is desirably provided with a vacuum box of its own.

The batt issuing from the machine may, for some purposes, be desirably laminated With other batts, desirably upon an intervening paper web lamination. The webs used, whether of paper or other material, are desirably sprayed with any appropriate adhesive, an ordinary flour and water paste being particularly suitable because it sets promptly when its water content is reduced upon contact with the fiber of the batt.

The spray may assist in aligning the fibers parallel to the direction of batt movement and adhesively joining them, but its primary purpose is to provide a finely atomized tmist which, the batt being subject to vaccum, will penetrate the batt to provide adhesive connection between the fibers at as many as possible of the points of fiber contact.

A number of adhesive nozzles can be used. In a preferred arrangement at least the first nozzle or nozzles may be directed tangentially of the vacuum pulley over which the forming screen moves at the top of the forming run, the nozzle or nozzles being directed parallel to the path of batt advance to further bring about alignment of the fiber with such path.

The invention further contemplates that a device embodying the invention may have sufficient width to form a very wide single batt or, by simply obstructing air flow to selected portions of the upwardly moving vacuum conveyor, one or more narrower batts may be formed and delivered concurrently. It is found that the edges of such batts can be very sharply and accurately defined. The definition may be achieved in part by the construction of the vacuum box and in part by a coating which closes certain longitudinal areas of the forming screen. However, for best results, I may also use mechanical means for dislodging loose fiber from the edges of the traveling batts, whereby such edges are sharply delineated.

In the drawings:

FIG. 1 is .a view in longitudinal section through onev embodiment of a batt forming device according to the present invention.

FIG. 2 is a view taken in section on the line 2-2 of FIG. 1, portions of the bafile and the leveling and redistributing rotors and the batt forming apron and its supporting grid being broken away.

FIG. 3 is a fragmentary view in front elevation of the grid which supports the batt forming screen as the grid is modified for dividing the batt into separate batt strips.

FIG. 4 is a fragmentary view taken in section on the line 4-4 of FIG. 3. 7

FIG. 5 is a detail view on an enlarged scale taken in section on the line 55 of FIG. 3

FIG. 6 is a fragmentary front elevation of a batt forming screen or foraminous apron representing a modified embodiment of the device shown in FIG. 2.

FIG. 7 is a fragmentary detail view on an enlarged scale taken in section on the line 77 of FIG. 6.

FIG. 8 is a view in transverse horizontal cross section on a greatly enlarged scale through a modified vacuum box embodying the invention.

FIG. 9 is a view on an enlarged scale taken in section on line 99 of FIG. 8.

FIG. 10 is a fragmentary detail view in perspective showing a modified form of rotary fiber redistributing device.

FIG. 11 is a fragmentary detail view in perspective showing a modified apron type fiber redistributing device.

FIG. 12 is a fragmentary detail view similar toa portion of FIG. 1 and showing a rotary type fiber redistributing device modified in the device of FIG. 1 only from its direction of rotation.

FIG. 13 is a fragmentary detail View similar to a portion of FIG. 1 but on a reduced scale showing a modified embodiment of the batt forming device and the material redistributing device.

FIG. 14 is a detail view taken in section on the line 1414 of FIG. 13, with portions of the batt forming apron and the infeed conveyor broken away.

FIG. 15 is a view in vertical transverse section somewhat similar to FIG. 14, portions of the batt forming apron being broken away to expose a modified partitioned vacuum box and vacuum pulley.

FIG. 16 is a view in perspective of modified apparatus embodying the invention, portions of the housing and conveyor being broken away.

FIG. 17 is a detail view taken in section on the line 17-17 of FIG. 16.

FIG. 18 is a fragmentary detail view in front elevation of a batt forming screen or apron used in the device of FIG. 16.

FIG. 19 is a view taken in section on the line 19-19 of FIG. 16.

FIG. 20 is a view taken in section on the line 20-20 of FIG. 16.

FIG. 21 is a view taken in section on the line 2121 of FIG. 16.

FIG. 22 is a diagrammatic longitudinal sectional view showing means for coating and laminating batts following their delivery from the forming devices.

Reference is first made to the device of FIGS. 1 and 2:

The batt forming material 10 supplied through the pneumatic conveyor pipe 11 and separator 12 to the accumulator chamber 15 is discharged from the separator 12 upon an infeed conveyor apron 16. The air used in the pneumatic conveyor 11 is discharged through pipe 13, or through the vacuum box hereinafter referred to, along with any dust.

The upper run of the conveyor 16 moves slowly through the accumulator chamber 15, being supported on parallel bars at 17. Deliveries of the bait forming material from a conventional hammer mill (not shown) or other source may be irregular. However, the material is allowed to build up to a substantial depth upon the upper run of conveyor 16, whereby such conveyor serves as an accumulator device from which the batt forming mechanism hereinafter described can withdraw material as required.

To assure uniform operation of the batt forming device, excess material ultimately reaching the batt forming device is constantly returned by a reversely movable paddle wheel 18 which rotates relatively slowly and merely displaces excess stock rearwardly as the accumulating conveyor 16 and batt forming conveyor 2e advance. By way of example and not by way of limitation, this paddle wheel 18 has ordinarily been operated at about 40 r.p.m.

For some purposes, the paddle wheel should desirably be located well above the infeed conveyor 16 and in fairly close proximity to the batt forming conveyor apron 29 as shown in FIG. 1, the object being to reduce the deposit of batt forming material on the apron 20 to a thickness such that there remains sufficient air movement through the deposited batt so that fibrous material on the surface thereof will be subjected to the action of the high speed redistributing device hereinafter referred to. For other purposes, the corresponding wheel is located in close proximity to the accumulating feed conveyor 16 and remote from the batt forming conveyor apron 20 to produce a more or less uniform level of flow to the batt forming conveyor as shown in FIG. 13.

The batt forming device comprises a foraminous conveyor apron 20 having a generally upright run as clearly shown in FIG. 1 which moves upwardly from its lower pulley 21 to its upper pulley 22.

Between the upwardly moving run upon which the batt is formed and the returning run on the rear side of the conveyor, there is a vacuum box 25 having one or more vacuum pipes 26, 27 through which air is withdrawn by any suitable blower or vacuum pump (not shown). While I do not want to be limited to any particular degree of vacuum, it is practical to exhaust air from the vacuum box at such a rate as to maintain a vacuum amounting to two and one quarter inches of water in the box when there is batt forming material deposited on the conveyor to the depth indicated.

In practice, the front of the box is provided with rather closely placed upright bars 23 connected by transverse rods 29 (see FIG. 2). The foraminous conveyor apron 26) may comprise either a screen cloth apron as diagrammatically shown in FIG. 2, or a series of transverse horizontal bars 2% riding on the upright bars 28 as shown in FIG. 14 and connected at their ends with the conveyor chains 30. In either case, the foraminous conveyor apron operates over the otherwise open face of box 25 so that material at the face of the conveyor is held to the conveyor apron by air movement into the box induced by pressure differential between the air within the accumulator chamber 15 and the reduced pressure existing in the vacuum box 25 and communicated therefrom through the conveyor apron and any previously deposited material to the surface of which newly arriving material adheres.

As the apron 20 moves upwardly, portions of the batt forming material 10 continuously advanced toward the face of the apron by the slow movement of the accumulator conveyor 16 will become adherent to the upwardly moving apron of the screen conveyor. As aforesaid, the deposit of such material on the conveyor will be a function of the pressure differential and the nature of the stock and will tend to be approximately uniform in depth and density, but certain irregularities will occur. This will happen, in particular, when there are knots or tangles of mutually adherent fibers.

But for the wheel 18, the batt forming material might accumulate on the face of the batt forming conveyor apron to a depth such that the material at the surface of the batt would be very lightly held. The spacing of the paddle 18 from the conveyor apron is such as to arbitrarily shear away from the face of the deposited batt a sufficient amount of material so that the particles which remain will be held subject to substantial pressure toward the batt forming conveyor. It is the object of this organization to assure the possibility of rearranging and compacting and unifying the remaining material at the surface of the batt without loss of any thereof except such as may be required incidentally to the rearranging and unifying operation.

As the deposited and roughly uniform batt reaches a condition of substantially uniform density, it passes beneath the relatively high speed stock rearranging and unifying device 35 which, in the FIG. 1 construction, comprises a paddle wheel of small radius having its own drive at about 2600 r.p.m. from motor 36. It is ordinarily rotated counterclockwise as viewed in FIG. 1 so that its paddles move contrary to the direction of the advancing batt. However, at this speed, the peripheral speed of the paddles so greatly exceeds the lineal movement of the clockwise as shown in FIG. 12 whereby any material removed will be thrown upwardly and rearwardly across the top of the accumulator chamber to become commingled With newly arrived material. In the event the wheel is rotated contna to the batt advance, as shown in FIG. 1, the commingling of displaced material with newly arrived material is achieved in very substantial degree by the paddle wheel 18.

An advantage of rotating the rearranging rotor against the direction of batt advance as shown in FIG. 1 lies in the fact that it is possible to use therewith the baffle 37 which extends downwardly from the housing top 15 into immediate proximity to the rotor 35. Beyond this baffle the housing is open above the level of the rotor. The direction of rotation tends to confine all of the displaced fiber within the housing. In the FIG. 12 construction such a bafile is omitted, as the fiber would be thrown out of the housing.

It is recognized that leveling devices are well known in the art in other connections, but the stock rearranging device 35 of the present invention is used in combination with the opposed vacuum box so that the device operates during the continued exposure of batt material to a pressure differential communicated through the conveyor apron upon which it is formed. Under these circumstances, relatively little of the stock will be dislodged completely during rearrangement of surface material. On the contrary, the primary effect of the device 35 will be to redistribute the material, correcting any inequalities in the face of the batt and leaving the entire batt surface quite smooth, compact and uniform. The combination of the generally upright run of the foraminous conveyor apron and the high speed rearranging device and the means for establishing continued differential pressure through the deposited batt during the stock rearranging operation produces notably more accurate results in the way of volumetric uniformity than it has heretofore been possible to achieve. By way of example, but without limitation, the batt forming conveyor apron may be operated at a speed of approximately 60 feet per minute, the exact speed being determined largely by the rate at which batt delivery is desired. There appears to be no arbitrary limit 'to the speed at which this apron may be operated.

The delivered batt may be of any desired thickness, within reason. Samples have been produced ranging from less than an inch up to five inches, it being necessary to increase the pressure differential roughly in proportion to increases in the thickness at which the batt is deposited on the batt forming apron.

The batt formed as above described is desirably sub- ,jected while still on the vacuum pulley 22 to a spray of finely atomized adhesive from the nozzle 38 which has a high pressure air connection at 39. Because of the .finely atomized form of the spray and because of the movement of air through the batt toward the vacuum pulley 22, the mist of adhesive is carried into the batt where it unites the individual fiber without making the batt coarse or stiff. Moreover, if the nozzle is inclined toward parallelism with the direction of batt advance,

either with or against the direction of such advanc'e,the force of the blast from the nozzle will further tend to align the fibers in the surface of the batt in parallelism with the direction of batt movement, thus augmenting the fiber rectification achieved by the rotor 35. It is for this reason that the nozzle is directed almost tangentially of the vacuum pulley 22 in FIG. 1.

For most purposes the batt as delivered from the machine is already in condition for its ultimate use. In

FIG. 22,- I have shown two of the pieces of apparatus as already described delivering batts 'to be laminated with each other and with paper webs 40, 41, 42 to make up a composite, multi-ply batt. For this purpose, the batts themselves, or the webs 40, 41 and 42, desirably have their contacting surfaces adhesively coated by means of adhesive sprays 46 or the roller coaters 43 which are conventionally provided with adhesive from troughs 44- by means of transfer rolls 45. Any suitable adhesive may be used, though ordinary starch adhesive may be preferred for the particular purposes I have in mind, which include the production of thermal insulation and furniture wrapping pads. For making sanitary napkin pads, the batt will be used as it issues from housing 15- and simply cut into pads of appropriate sizes, using standard procedures.

Certain kinds of material may not constitute desirably discrete particles When fed into the accumulator chamber 15. For example, pulp derived by comminuting paper waste may have some of the fibers still adherent to each other. These fibers form little knots when they are picked up by the screen conveyor apron 20 for batt forming purposes. Since an unusually high degree of uniformity is one of the objects sought, it is desirable to eliminate all such irregularities such as knots or loose fiber. To this end, I may provide the high speed rearranging device 35 with combing teeth or pegs 48. These may be disposed on the free margins of the paddles 49 as shown in FIG. 10.

The particle rearranging device 50 of FIG. 13 comprises a conveyor apron having its batt contacting run moving generally parallel to the upwardly moving run of the apron 200 upon which the batt is being formed. The movement of the batt forming run and the opposing run of conveyor 50 may be in the same or opposite directions but there should be a substantial differential movement for the desired particle displacing action. The upward motion of the apron 200 is relatively slow, whereas the motion of the opposed apron 50* is a relatively high speed movement achieved, as in the device of FIG. 1, by having the apron 50 provided with its own separate motor at 360. The upper and lower pulleys 51 and 52 over which the apron 50 operates are mounted on slides 53 and '54, respectively, these being adjustable along the ways 55 and 56 by means of the adjusting screws 57, 58. The apron 56 is not only bodily adjustable but either end may be adjusted independently to set the apron 50 at an angle to converge toward (or diverge from) apron 200 Desirably, although not necessarily, the apron 50 is provided with its own vacuum box at 60 from which air is evacuated through the exhaust pipe 61. The batt forming conveyor apron 200 is, of course, operated over the same vacuum box 25 already described.

The conveyor apron 50 of the high speed rearranging device may, like the high speed paddle wheel 35, be provided, if desired, with combing pegs or teeth 62 as shown in FIG. 11. I

The accumulator and batt forming chamber 15, and the aprons operating therein, are desirably of suitable width to be adapted to produce batts of maximum desired width. In order to produce batts of lesser width, all that is required is to mask off any desired portions of the batt forming screen conveyor aprons either by applying a masking tape or the like directly to the face of the apron as indicated at 65 in FIG. 6 and FIG. 7 or by applying bafile plates 68 behind the apron as shown in FIGS. 3, 4 and 5. The bafile plates '68 may conveniently be mounted by attaching them to notched members 69 adjustably engaged over the rods 29 to provide supports to which the plates 68 may be screwed as shown in FIG. 4 and FIG. 5.

In either case, that portion of the apron surface which is bafiled or shut off from the establishment of pressure differential will accumulate no material and form no batt. By way of exemplification, a single masking tape or plate is shown in each of FIGS. 3 to 7, thereby forming two well-defined

batts

380, 381 as indicated at FIGS. 5 and 7.

machine, the width of each batt being equal to the length of the desired napkin pad so that the pads may simply be die cut transversely from the several batts as in my Patent No. 2,131,808.

It is found that the margins of the webs of batt material formed by using less than the total width of the screen conveyor apron are quite sharply defined and uniformly built up to the full thickness and density of adjacent portions of the batt. Many other variations are possible.

FIGS. 8 and show the vacuum box 250 provided with vertical and transverse partitions 70 and 71 with separate

air withdrawal pipes

25, 27, 260, 270, leading from the various compartments in order further to promote uniformity of pressure differential to cause uniform deposits on the face of the forming screen 201. The pulley 220 is similarly compartmented and has

separate vacuum pipes

223 and 222 as shown in FIG. 15.

In this instance, the forming screen is not masked. The rotor shaft 75 has two types of

radial blades

76 and 77 anchored by set screws 78. The blades 77 are serrated at 79 to hold into the rotor some straps of leather or the like which, in the course of high speed rotation of rotor '75, wipe accumulations of fiber from those portions of the screen 201 which are in the path of the straps, thus producing well defined and laterally spaced batts.

If desired, these different devices for forming separate batts on a single screen can be used concurrently. In FIGS. 16 to 21, I have shown an arrangement in which the forming screen 204 has masking at 654 and 655 which is made by coating the screen with a liquid plastic adhesive or the like to fill its openings along a definite band upon which it is desired to divide the deposits of fiber. In consequence, the fiber will tend to deposit along separate paths as shown at 82 and 83. FIG. 19 shows these deposits to be rather rough. FIG. 20 shows how they have been leveled off by rotor 184, while FIG. 21 shows how the straps 804 carried by the blades of rotor 754 have cut away surplus material from the sides of the

batts

82 and 83 to leave these batts with sharply defined margins.

The device of FIGS. 16 and 17 is a preferred embodiment of the invention for other reasons:

I have found that if the forming screen is actuated at high velocity, the material accumulated on a conveyor such as that shown at 16 in FIG. 1 cannot be delivered to the forming screen dependably to produce on the screen with adequate certainty a batt or batts of uniform depth and density. This difficulty can be remedied by discharging the fibrous material against the screen at substantial velocities. However, there is a problem in connection with obtaining the requisite flow of material uniformly directly from a hammer mill without an accumulator. In the apparatus disclosed in FIGS. 16' and 17, the hammer mill 85 has the usual hopper at 86 to receive the fiber sheets or other material to be distintegrated by the hammers 87 against the hammer mill screen 88 through which the fiber is forced.

By using one or more blowers 89 to draw the fibers directly from the compartment or compartments 90 in the base of the hammer mill, the fibers are entrained in air which is also drawn through the hammer mill and its screen 88. Accordingly, I develop a reasonably uniform flow of fiber. The fiber and the air in which it is entrained passes through the pipes 91 to the respective blowers and thence through the discharge pipes 92 to separate nozzles 93 which are directed forcibly against the forming screen areas on which the batt or batts are formed.

Naturally not all of the material will adhere, notwithstanding the forcible projection against the screen and notwithstanding the pressure differential established through the screen by the

vacuum pipes

260, 270 and 26 and 27 (FIG. 15). However, I still retain the accumulator conveyor 16 in the bottom of the housing 15 so that as the forming screen 204 moves upwardly from its lower pulley 21, it draws fiber to itself from accumulating conveyor 16. It is against this somewhat loosely held fiber that the fiber newly arriving through the nozzles 93 is jetted by the air blast from the blowers 89, thereby tending to bind all of it in the batt. The resulting batt has its fibers very securely knit, and the batt margins and surface are smooth and sharply defined as indicated in FIG. 16 and FIG. 21. In this machine, the two

rotors

184 and 754 are usually of the same diameter and operated at the same speed. Speeds of 1800 to 3000 r.p.m. have been used, and in commercial practice a speed of 2600 r.p.m. has been adopted as standard. The figures are given by way of illustration and and not by Way of limitation. 1

It is desired to emphasize the fact that various features herein disclosed may be used interchangeably in the diiferent embodiments.

While the method of operation has been made clear in the foregoing description of the structure, it may be summarized as follows:

The batt forming material is attracted to an upright and desirably upwardly rnoving screen conveyor apron of some sort by means of pressure differential through the apron. To assure firmness of the deposit, the material drawn from that accumulated at the bottom of the apron path may be compacted and supplemented by forciby projecting additional material against it and toward the apron.

To assure that the surface of the deposited material will remain subject to sufficient pressure, the thickness of the deposited material may be arbitrarily reduced by a rotor and leveled off. While the material remains subject to the pressure differential holding it to the apron, it is then desirably redistributed as by being brushed, wiped, and/or combed either mechanically or by air turbulence or both together, the redistributing operation being sometimes supplemented or entirely conducted by a pneumatic blast directed along the path of movement desirably while the batt remains subject to the pressure differential.

The pneumatic blast may also incorporate finely divided adhesive throughout the batt to unite the particles thereof, whereby to unify the batt without making it stiff, the amount of adhesive used being barely suflicient to unite fibers where they contact each other.

The resulting batts have been found to be very uniform indensity and thickness and by mechanically removing material along the edges to a Well defined line, the margins as well as the surfaces of the batts are rendered neat and smooth.

I claim:

1. A method of assembling a batt, which method comprises the steps of establishing a pressure differential across a generally upright screen, projecting fibrous material at high velocity through space toward said screen, advancing upwardly upon said screen fibrous material adhering thereto, dislodging and rearranging fibrous material on the surface of the material advancing upwardly on said screen, accumulating fibrous material which fails to adhere to said screen and advancing such material toward said screen at a lower level than that at which freshly arriving fibrous material is projected thereon, the said pressure differential causing said accumulated and previously non-adherent material to cling to said screen in the pathof newly arriving projected material and subject to the impact thereof.

2. The method of claim 1 in further combination wtih the step of spraying toward said screen and upon the intervening fibrous material adhering thereto a finely atomized liquid adhesive material while the fibrous material is subject to pressure differential urging it toward said screen, whereby the adhesive liquid spray is drawn into the deposit of'fibrous material, the liquid being sprayed in quantities limited to be only sufiicient 9 to unite contacting fibers without unduly stilfening the resulting batt.

3. A batt forming device comprising upper and lower pulleys, a fora-minous belt trained about said pulleys and having an upwardly moving run, a vacuum box behind said run, means for establishing 'a pressure differential through said run, an accumulating conveyor moving toward said run and nozzle means above said accumulating conveyor for projecting fibrous material forcibly through free space against said run and against material previously accumulated on said run, whereby said projected material compacts said previously accumulated material and tends to adhere at the surface thereof, such portions as do not adhere falling by gravity onto the accumulating conveyor to be delivered thereby to said run for accumulation thereon.

4. The device of claim 3 in further combination with a leveling and rearranging rotor disposed in spaced relation to the run and above said nozzle means for acting upon fibrous material adhering to said run for leveling such material and forming a batt, surplus material dislodged by the leveling and rearranging rotor falling to said accumulating conveyor cfor redelivery toward said run.

5. A device of the character described comprising the combination with an accumulator housing and means for delivering fibrous batt forming material thereto, of an accumulator conveyor mounted within the housing and provided with longitudinally extending supporting run and means for driving the conveyor to advance said run from the point of material delivery, the said run being adapted to receive batt forming material delivered into the housing, a batt forming conveyor having an upper guide and a foraminous apron trained over said guide and having a generally upright run extending in the path of material on the run first mentioned and toward which the accumulator run aforesaid advances batt forming material, a box over which the upright run of the batt forming conveyor operates, said box having air discharging connections, means for operating said batt forming conveyor, means for establishing a pressure differential toward said box through the upright run of the foraminous conveyor apron for holding the batt forming material to the face of the apron to form a batt thereon during the upward movement of the apron, and means for displacing loose material and rearranging other material at the face of the batt during the upward movement thereof subject to pressure differential, the last mentioned means comprising a wiper having means operating it in proximity to the face of the batt and at a surface speed greatly exceeding the surface speed of the beatt, said wiper comprising a paddle wheel having blades of predetermined radius and flexible projections from at least one of said blades of sufficient radius to remove substantially all batt forming material from the batt forming conveyor at the sides of the batt formed thereon and whereby sharply to delineate the sides of the batt on the conveyor.

6. A device of the character described comprising the combination with an accumulator housing and means for delivering fibrous batt forming material thereto, of an accumulator conveyor mounted within the housing and provided with a longitudinally extending supporting run and means for driving the conveyor to advance said run from the point of material delivery, the said run being adapted to receive batt forming material delivered into the housing, a bastt forming conveyor having an upper guide and a foramino-us apron trained over said guide and having a generally upright run extending in the path of material on the run first mentioned and toward which the accumulator run aforesaid advances batt forming material, a box over which the upright run of the bait form-ing conveyor operates, said box having air discharging connections, means for operating said batt forming conveyor, means for establishing a pressure differential toward said box through the upright run of the foraminous conveyor apron for holding the batt forming material to the fiace of the apron during the upward movement of the apron, and means for displacing loose material and rearranging other material at the face of the batt forming material during the upward movement thereof subject to pressure differential, the last mentioned means comprising a wiper having means operating it in proximity to the face of the batt forming material and at a surface speed greatly exceeding the surface speed of the batt forming material, said batt forming conveyor being provided with longitudinally extending means for masking a portion of its surface intermediate its side margins whereby to form separate batts thereon.

7. The device of claim 6 in further combination with flexible strap means projecting from the wiper at intervals to correspond with the width of the desired batts, the projection of said strap means being sufiicient to dislodge mechanically from said batt forming conveyor substantially all batt forming material in the zones in which said straps are disposed, whereby sharply to delineate the batts formed on the batt forming conveyor.

8. The combination with a hammer mill having a feeding hopper, a hammer rotor and a grinding screen, of a closed chamber beneath the grinding screen having a partition subdividing it, a pair of blowers having inlets connected with said chamber at opposite sides of the partition and adapted to draw ,air from said hopper through said grinding screen with entrained material ground by said rotor, an upwardly moving batt forming screen having a vacuum box behind it and discharge pipes iirom the respective blowers directed toward said batt forming screen and transversely to its direction of movement for the forcible projection of said air and entrained material against the batt forming screen.

9. The device of claim 8 in which the batt forming screen comprises an endless conveyor having upper and lower guides, the projection of material against the batt forming screen being intermediate said guides, means above the pipes from said blowers and in the path of movement of a batt formed on the batt forming screen for leveling the material of the batt, and an accumulating conveyor below the level of said pipes upon which material displaced by the leveling device can fall, said accumulating conveyor having means for advancing it toward the batt forming conveyor, and the vacuum box extending to a level sufficiently low to attract to the batt forming conveyor material delivered thereto by the accumulating conveyor.

10. The device of claim 9 in which the batt forming screen has masking means extending longitudinally intermediate its side margins, whereby to form separate batts on a said batt forming screen, the respective Pipes from said blowers being directed toward screen portions at opposite sides of the masking means.

11 The device of claim 10 in which said leveling device comprises a paddle wheel having blades of such radius as to be disposed in spaced relation to the batt forming screen, at least one of said blades having a wiper projecting from the blade into immediate proximity to the face of the forming screen in substantial registry with the masking means thereof, whereby to sharply delineate the margin of a batt extending to said masking means.

12. A batt forming device comprising means for moving finely divided fibers of batt forming material in a generally horizontal direction, a generally vertical conveyor screen toward which said batt forming material is delivered by said means, means for moving said vertical screen in an upward direction, a vacuum box behind said vertical screen to draw said batt forming material pneumatically against said screen to form a relatively thick batt thereon, first means for metering the batt forming material to establish a predetermined batt thickness on said vertical screen, second means to reduce the thickness of the batt to substantially its final dimension and thereby also to increase air flow through the remaining material, said second means including means to dislodge batt form- 1 1 ing material from said batt and. rearrange it in the presence of gravity and the flow of air to said vacuum box for redeposit of some of the dislodged material on portions of said batt below said second means.

13. The device of claim 12 in further combination with an adhesive spray nozzle directing upon the exposed surface of the formed batt a finely atomized spray of adhesive after said batt has been acted on by said second means and while the material of the batt is subject to said pressure differential whereby the adhesive is drawn into the deposited finely divided material, the spray being in such quantities as to tend to join fibers at their points of contact throughout the material without unduly stiffening the material.

14. A method of forming a batt from finely divided fibers of batt forming material and comprising the steps of assembling particles of said batt forming material into a relatively thick batt, metering said material to reduce said batt to a predetermined thickness, moving the batt in a generally upright direction, subjecting the upwardly movingbatt to a pressure differential tending to hold such material at the surface of the batt, still further reducing the thickness of the batt including the steps of dislodging batt material from said batt and thereby also increasing air flow through the remaining material and rearranging such material in the presence of gravity and .flow of air resultant from said pressure differential for redeposit of some of said dislodged material on said batt at a point below which it was dislodged therefrom, and directing upon the exposed surface of the formed batt a finely atomized spray of adhesive after the batt has been reduced in thickness and while the material of the batt is subject to said pressure differential whereby the adhesive is drawn into the deposited finely divided material, the

12 spray being in such quantities as to tend to join fibers at their points of contact throughout the material without unduly stiffening the material.

15. The device of claim 12 including means to separate the batt into discrete portions before the batt leaves the vertical conveyor screen.

16. The device of claim 15 in which the last mentioned means comprises means for dislodging from the screen batt forming material previously deposited thereon between said portions.

References Cited in the file of this patent UNITED STATES PATENTS 480,588 Kellner Aug. 9, 1892 506,960 White et al. Oct. 17, 1893 561,689 Patterson June 9, 1896 889,461 Haskell et al June 2, 1908 1,834,309 Harney Dec. 1, 1931 1,961,272 Williams June 5, 1934 2,057,466 Schur Oct. 13, 1936 2,077,095 Cady Apr. 13, 1937 2,086,757 Williams July 13, 1937 2,318,243 McClure May 4, 1943 2,319,666 Drill May 18, 1943 2,389,024 Brownlee Nov. 13, 1945 2,569,765 Kellett et a1 Oct. 2, 1951 2,577,784 Lynarn Dec. 11, 1951 2,714,081 Burgon July 26, 1955 2,736,362 Slayter et a1 Feb. 28, 1956 2,743,758 Uschmann May 1, 1956 2,920,355 Clark Jan. 12, 1960 FOREIGN PATENTS 487,161 Great Britain June 15, 1938

Claims

1. A METHOD OF ASSEMBLING A BATT, WHICH METHOD COMPRISES THE STEPS OF ESTABLISHING A PRESSURE DIFFERENTIAL ACROSS A GENERALLY UPRIGHT SCREEN, PROJECTING FIBROUS MATERIAL AT HIGH VELOCITY THROUGH SPACE TOWARD SAID SCREEN, ADVANCING UPWARDLY UPON SAID SCREEN FIBROUS MATERIAL ADHERING THERETO, DISLODGING AND REARRANGING FIBROUS MATERIAL ON THE SURFACE OF THE MATERIAL ADVANCING UPWARDLY ON SAID SCREEN, ACCUMULATING FIBROUS MATERIAL WHICH FAILS TO ADHERE TO SAID SCREEN AND ADVANCING SUCH MATERIAL TOWARD SAID SCREEN AT A LOWER LEVEL THAN THAN THAT AT WHICH FRESHLY ARRIVING FIBROUS MATERIAL IS PROJECTED THEREON, THE SAID PRESSURE DIFFERENTIAL CASUSING SAID ACCUMULATED AND PREVIOUSLY NON-ADHERENT MATERIAL TO CLING TO SAID SCREEN IN THE PATH OF NEWLEY ARRIVING PROJECTED MATERIAL AND SUBJECT TO THE IMPACT THEREOF.

12. A BATT FORMING DEVICE COMPRISING MEANS FOR MOVING FINELY DIVIDED FIBERS OF BATT FORMING MATERIAL IN A GENERALLY HORIZONTAL DIRECTION, A GENERALLY VERTICAL CONVEYOR SCREEN TOWARD WHICH SAID BATT FORMING MATERIAL IS DELIVERED BY SAID MEANS, MEANS FOR MOVING SAID VERTICAL SCREEN IN AN UPWARD DIRECTION, A VACUUM BOX BEHIND SAID VERICAL SCREEN TO DRAW SAID BATT FORMING MATERIAL PNEUMATICALLY AGAINST SAID SCREEN TO FORM A RELATIVELY THICK BATT THEREON, FIRST MEANS FOR METERING THE BATT FORMING MATERIAL TO ESTABLISH A PREDETERMINED BATT THICKNESS ON SAID VERTICAL SCREEN, SECOND MEANS TO REDUCE THE THICKNESS OF THE BATT TO SUBSTANTIALLY ITS FINAL DIMENSION AND THEREBY ALSO TO INCREASE AIR FLOW THROUGH THE REMAINING MATERIAL, SAID SECOND MEANS INCLUDING MEANS TO DISLOGE BATT FORMING MATERIAL FROM SAID BATT AND REARRANGE IT IN THE PRESENCE OF GRAVITY AND THE FLOW OF AIR TO SAID VACUUM BOXFOR REDEPOSIT OF SOME OF THE DISLODGED MATERIAL ON PORTIONS OF SAID BATT BELOW SAID SECOND MEANS.