US1952208A - Fiber sheet and its manufacture - Google Patents

Description

March 27, 1934. V E. H. Hussey 1,952208 FIBER SHEET AND ITS MANUFACTURE I Filed May 18, 1931 is; Q

Patented4 Mar-. 27,` 1934 man SHEET AND rrs MANUFACTURE Erwin H. Hussey, Springeld, Ohio Application May 18, 1931, Serial No. 538,088

9,Claims. (Cl. 154-23) This invention relates to the manufacture of thick brous sheets and, among other objects, aims to provide an eicient and economical process for making thick brous sheets in which the 5 bers are interconnected without impairing the insulating qualities of the4 sheet. U

'151e nature of the invention may be readily understood by reference to one yillustrative embodiment thereof shown in the accompanying l drawing. f

In said drawing, A

`If'ig. 1 is a more or less diagrammatic view showing an elevation of the devices for initially forming the sheet; and

'15 Fig. 2 is a similar elevation of apparatus forming a continuation Fig. 1.

In the illustrative process, the'mass of bers are interconnected by an adhesive, as distin- 90 guished from connecting by felting the bers together, in order to provide a sheet cf looser character than a felted sheet wherein compression or an intimate association of bers is necessary to effect a felting .and interlocking of the '25 bers. The latter form of sheet is of course much denserv in character and does not possess the insulating characteristics of the more porous sheet.

To provide a porous or loose sheet of this char- 80 acter, treatments which tend to compact the bers are avoided. To this end, the formation of the sheet by the use of a water pulp is avoided because in the latter process thedraining of the water away from the pulp layer inevitably produces a rather cle and undesirable (from the insulating standpoint) compacting of the bers. Instead, the bers are used without a water vehicle and are interconnected by the use of an adhesive which is applied to the bers. In the 4 present instance, the adhesive is applied and excess adhesive removed, befcreany sheet forming operations, in order to avoid the .disturbance of the loose layer of bers by any subsequent operation of this character,

To secure a uniformly thick layer of bers, the initially deposited layer of ber is repeatedly levelled by removal of bers forming high spots in the layer, and then the levelled layer is picked apart and uniformly redeposited in another layer. The successive levelin'gs and redepositingoperations eventually produce a brous layer quite as loose as the original layer. and in which the bers are uniformly distributed and which is of uniform thickness. The sheet is then dried to set the adhesive and preferably very slightly comof the apparatus. shown in device 10.

Apressed in order to hold ldown projecting bits of ber and provide a smoother surface.

In the drawing is illustrated diagrammatically one procedure for performing the inventive process. The ber, which may be of vegetable, wood or mineralcharacter or a mixture of these, is employed in dry form, that is, with only about 10 to 15% moisture, which is approximately the natural moisturev content of the ber. It is first subjected to a coarse shredding operation in a hammer machine or hog, diagrammatically indicated at 10, and then later to a ne shredding operation in apparatus such as a single disk brator which may be purchased on the market.

AA iine shredding device is here indicated at 11 receiving the coarse shredded bers from the 'Ihe nely shredded bers are then screened to remove dirt and so-called nes and are then delivered to a device, represented at 12, for mixing the ber with an appropriate adhesive.' For this purpose, a mixing device, such as is used for mixing cattle feed with molasses, may advantageously beemployed. Mixers of this character may be purchased on the open market. A great variety of.adhesives may be used, such as starch and dextrine adhesives, -glue or rosin, or for to water and weather-proof the bers, a high melting point asphalt may be employed. Adhesive somewhat in excess of that necessary to coat the bers is introduced`into the rnixer and the excess adhesive is later expressed from the bers by the subsequent operations, thereby insuring an adequate coating of the bers. The excess adhesive may conveniently be expressed from the bers by delivering the mass of bersv from the adhesive mixer 12 to an enclosed screw conveyor 13 which carries the mass of ber along and forces it through a conned passage 14 not provided with any screw conveyor. The friction of the passage coupled with the action of'the conveyor in attempting to advance the mass of .bers places them under substantial compression and expresses the excess adhesive which may pass through the perforations 15 in the walls of the passage 14 from which it is collected in a receptacle 16 for re-use. The compressed ber is then delivered to agitating apparatus, indicated diagrammatieally at l?, which generally loosens the compressed vbers and delivers the loosened mass of adhesive coated bers to a. distributing device 18 in the form of a worm conveyor having an inclined delivery edge 19. This device with its inclined delivery edge serves some purposes, such as where it is desired fully lio to deliver the fiber fairly uniformly across a belt levelled by the brush roll 27, as above described, conveyor 20 (shown in Fig. l as `travelling perafter which, the sheet is subjected, as aforesaid, to pendicularly to the plane ofthe drawing and in drying and other subsequent operations. Fig. 2 as travelling parallel therewith. The layer Obviously, the invention is not limited to the of fibers deposited on the belt 20, while fairly details of the illustrative embodiment herein iluniform as regards to the rate of feed and dislustrated and described. Moreover, it is not intribution across the sheet, is not uniform in dispensable that all features of the invention be thickness, as indicated in Fig. 2. used conjointly, since various features may ad- To improve the uniformity oi the sheet, the vantageously be employed in different combinalayer of fibers is picked apart by a rotating picker tions and subf-combinations. roll 21 which serves not only to loosen the fibers Having described my invention, I claim: but to distribute inequalities in the supply of l. The method of making sheet maerial of the fiber. From the picker roll the fibers fall upon character described which is characterized by a continuously travelling conveyor 22, the layer covering a mass of fiber with a liquid adhesive so on this conveyor being somewhat more uniforml asto coat the individual bers, agitating'said mass both in character and thickness than on the conto loosen and separate the coated bers and deveyor 20. inequalities in the thickness of the positing the same in a sheet like layer in loose sheet lare removed by a rotating brush roll 253 and unfelted condition, passing said shee'; under a whose direction of travel is opposite that of the rotary levelling brush to remove high spots in said conveyor 22 and which serves to remove the fiber sheet, and then drying said sheet to permit the in the high spots on the sheet and throw it back adhesive to set. toward the point of delivery where it is moreor 2. The method of making sheet material of the less uniformly scattered in the layer of fiber. character described which is characterized by A cleaning brush roll 24 rotating in a direction mechanically agitating a mass of fibers coated opposed to the roll 23, serves to remove fiber adwith liquid adhesive to loosen and separate them, hering to the brush roll. The levelled layer of depositing them in loose condition in a layer, and fibers is then advanced to another picker roll 25 picking said layer apart and redistributing the which serves again to loosen the layer of fibers fiber in another layer to secure more even `disand further to redistribute any inequalities in tribution of the ber in the layer and to produce distribution of ber throughout the layer and to a more uniform layer thickness without the use deposit the fibers upon another continuously of substantial pressure.

travelled conveyor 26. The slight inequalities in 3. The method of making thick fibrous sheet thieknessin this layer are removed by another insulating material which is characterized by rotating brush roll 27 similar to the roll 23 leavmixing disintegrated fiber with an adhesive, forcing a levelled loose fibrous layer 28 which is not ing the mass through a confined passage to comonly uniform in thickness, but in which the fibers press it and discharge excess adhesive, loosening are uniformly distributed. If desiredthe thickthe fibrous mass and depositing itin a. layer on a ness of the fibrous sheet may be varied by regus continuously travelling carrier, continuously tearlat'ing the relative speeds between conveyors 20 ing said layer .apart to loosen the iiber and reand 22 and between 22 and 26. depositing it in a layer on a continuously travelvA cleaning brush roll 29, similar to the roll 24, ling carrier to improve the uniformity of the is provided for the brush roll 2'?. 'I'he fibrous layer, passing said layer under a rotating leveller layer 28 is then Carried by the eOnVeyOi 26 01' to remove the bers in the high spots in said layer,

successive conveyors which are advantageously and then drying the sheet.

supported level by theusual rolls e0 through the 4. The method of making thick sheet insulating 12o necessary drying Operations. during which'thev material 'which is characterized by mechanically adhesive sets. Preferably, the sheet is given an agitating a mass of fibers coated with a liquid initial drying Operatien sumeient to permit it to adhesive to loosen and separate them, depositing be cut transversely into sections for convenient them in loose condition to form a layer without handling in the Cutting Operations in which the the use of compression, feeding said layer to a sheet is cut into desired commercial sizes. Preferpicker roll which pulls the ber apart and conably, during the `.drying Operations or until the tinuously discharges it in a layer upon a continuadhesive has Set;y slight Pressure bym-eens 0f a ously travelling carrier, and then passing the slnooth belt 0r Otherwise is applied t0 the surface .layer under a. rotating brush roll to remove the of the sheet to hold down any resilient ilber ends fiber in high spots on said layer. v which may-project above the true surface 0f the 5.l The method of making thick sheet insmeting layer. thus providing e fibrous sheet which has material which is characterized by meeha'nieeuy relatively smooth surface. Thisbelt or other comagit-,ating a mass of fibers coated with a, nquid Dressing means may alsO serve t0 gauge the Sheet adhesive to loosen andseparate them, delivering to standard or accurate thickness- .l said fibers, in loose condition, to a continuously It will be understood from the foregoing that travelling carrier and allowing them to form a the sheet is Very Porous and loose in ehslseter. loose unfelted j layer; repeatedly mechanically and that the fibers are held together or interconseparating the fibers in the. layer 'and then denested by the adhesive With sumeient rlnness t0 positing them again upon a travelling carrier; 1 preserve the integrity of 'the sheet.- and, following each depositof the bers in layer 140 If it be desired to provide a sheet in which the form, passing the same under a rotating brush surface is formed of flner fibers. this can be advanroll to level the sheet by removing the fiber in the tageously don'e by rst depositing uponthe nal high spots in the layer.

conveyor 26; athin layer of lneflber in the man- 6. 'I'he method of. making thick porous fibrous nerI previously described. Then a, layer of coarse. sheets which is characterized by mechanically ber is deposited uPOn the ne ber lsyiel The agitating a mass of'fibers thoroughly coated with coarse fiber layer may be levelled or not, dependliquid adhesive to loosen and separate-them, reing upon the character of its surface and then, if peatedly depositing said iber in loose condition desired, a top layer of ne ber maybe deposited on a continuously travelling carrier followed by on the layerlof coarse fiber and the whole sheet a repeated levelling of the sheet by removing the iiber in the high spots in said layer, thereby fo ing a. loose sheet-like layer of substantially uniform thickness and condition, and then drying said sheet and permitting the adhesive to set.

7. The method of making thick, loose brous sheets of the character described which is characterized by covering a mass of-fiber with a liquid with liquid adhesive to loosen and separate them, depositing them in loose condition to form a layer without the use of substantial compression, levelling said layer by removing the iiber forming high spots in said layer, and then drying said layer to permit the adhesive to set.

9. The method oi' making thick fibrous sheet material of the character described which is characterized by covering a mass of ber with a liquid adhesive so as thoroughly to coat the individual bers, separating the excess adhesive, mechanically agitating the coated fibers to separate and loosen them, depositing them in'loose condition in the form of a thick layer in substantially unfelted condition, and then drying said layer to permit the adhesive to set.

ERWIN H. HUSSEY.

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