US2752639A

US2752639A - Volumetric feeder for fibrous materials

Info

Publication number: US2752639A
Application number: US361793A
Authority: US
Inventors: Arthur L Mottet
Original assignee: Long-Bell Lumber Co
Current assignee: Long-Bell Lumber Co
Priority date: 1953-06-15
Filing date: 1953-06-15
Publication date: 1956-07-03
Anticipated expiration: 1973-07-03

Description

July 3, 1956 A. L. MOTTET VOLUMETRIC FEEDER FOR FIBROUS MATERIALS Filed June 15, 1953 1 l I I I l ll INVENTOR. rl. M02 2 e z a A "v" u P4 W is? lllllllll IIIL 2,752,639 VOLUMETRIC FEEDER FOR FIBROUS MATERIALS Arthur L. Mottet, Longview, Wash., assignor to The Long- Bell Lumber Company, Longview, Wash, 3 corporation of Missouri Application June 15, 1953, Serial No. 361,793 4 Claims. (01. 19-96) This invention relates to a volumetric feeder for fibrous materials, and particularly pertains to apparatus for continuously delivering fibrous material such as defibered wood at a predetermined constant volumetric rate to collecting or conveying means where it is ready for further processing.

In certain applications it is desirable to provide a feeder for fibrous material which will feed the material volumetrically at a uniform continuous rate for subsequent processing operations. For example, in the manufacture of pressed fiberboard by the dry process, wood first is reduced to fibrous form. The resulting fibrous product then is passed continuously through apparatus for coating it with resin, for forming it into felts or mats, and for pressing it into fiberboard of the selected density. In order to operate the process satisfactorily and in order to obtain mats and fiberboards of uniform density it is necessary that the fiber be fed into the various processing units at a constant rate of volume.

This obviously is a result that is difficult of accomplishment. In the first place, the rate of fiber production usually is not constant. In the second place, the char acter of the fibers is such that they tend to clump together and form flocs, which makes it difficult to feed them uniformly. Further, the fibers tend to hang up, or to jam, and plug the units of metering apparatus through which they may be passed. Still further, it is difficult to control and vary the rate of fiber feed within carefully determined limits because of the foregoing factors and because of the very low density of the fiber material which is handled.

I now have discovered that the foregoing and other difiiculties inherent in volumetric fiber feeding may be overcome through the use of apparatus described in the accompanying specification and claims, considered together with the drawings, wherein:

Figure 1 is a plan view, partly in section, of the presently described volumetric feeder for fibrous material; and

Figure 2 is a view in side elevation of the apparatus of Figure 1, partly broken away, better to illustrate the interior construction.

As is illustrated in the drawings, the presently described volumetric feeder comprises a housing the top of which communicates with feed chute or hopper 12. The discharge opening in chute 12 has a width or thickness at, the significance of which is to be discussed below; a depth substantially codimensional with the corresponding dimension of the apparatus; and an indeterminant height which may, however, be quite substantial. In this way a storage space is afforded to build up a reservoir of fibrous material, thereby compensating for fluctuations in fiber feed, such as may occur, for example, during the defibering of wood blocks.

Chute 12 tapers outwardly and downwardly and extends within housing It to such an extent that its discharge end is immediately adjacent a pair of

feed rolls

14, 16. These are stationed side by side immediately rolls.

below the chute for receiving the material discharged thereby in the area between the rolls.

The rolls are provided with

spikes

18, 20 for engaging the fibrous material and for carrying it into the area be- Feed roll 14 is rotatably mount nalled in bearings 24, mounted on a shaft 28

journalle Bearings

24, 26 are mounted on ed on a shaft 22 jour- 26. Feed roll 16 is rotatably d in

bearings

30, 32. a frame member provided with slots 27, and

bearings

30, 32 are similarly mounted with slots 33 so that the position of the two feed rolls relative to each other may be varied as desired.

It is to be noted that in order to have a uniform feed of fibrous material, such as wood fibers, between rolls I4 and 16, one or more of several critical factors must be observed. In the first place, the should be substantial as compared the sidewalls of chute 12 should possible to the surfaces of rolls 114,

surfaces of the two rolls become restricted of the side walls of the chute.

diameter b of the rolls with the corresponding extend as closely as 16. Thus the opposed continuations Also, and of particular importance, the distance 0 separating the opposed surfaces should be substantially less than of the two feed rolls the corresponding parallel width on thickness a of the chute opening. Thus,

0 should be between A1 and one-half a.

fibers present mat which can be passed at a uni Under these conditions it the column of fiber within chute a, This insures that the loose, fluffy mass of in the chute will be compacted to a coherent preferably about rate between the be apparent that will move in the form will 12 direction of the feed rolls uniformly at substantially the same rate as the compressed column moves between the rolls.

Drive means are provided for at the desired rate.

driving feed rolls 14,

16 in the feed direction synchronously with each other In the illustrated form the drive comprises a worm gear 34 keyed to shaft 22 and a worm gear 36 keyed to shaft 28. respectively by

worms

38, 40

It carries on one of its ends through belt 50 to pulley 52 on 5'4. In this manner roll 14 may These two gears are driven splined to a common shaft 42. Shaft 42 in turn is journalled in

bearings

44, 46. the pulley 48 connected the variable speed motor be driven clockwise and roll 16 counterclockwise, as viewed in Figure 2, synchronously but very slowly, for

example, at a speed of but 1 or 2 revolutions per minute.

Fibers transmitted between roll s 14, 16 are in a co herent compressed condition as has been indicated above.

Accordingly, in this condition ing for dislodging individual they are amenable to combfibers which may then be dispersed and collected for subsequent processing. In the illustrated form, the combing a combing roll 56. teeth 58 which are dimensioned an 18, 20 on the feed rolls.

means employed comprises It is provided with a plurality of d spaced to clear teeth The teeth of the combing roll project well within the fiber compression area sovthat they act upon the compressed fibers, disentangling them and combing out individual fibers, thereby avoiding the dropping away of fibrous clumps from the apparatus.

The combing roll assembly includes a shaft 60 which is journalled in

bearings

62, 64. pulley 66, interconnected through on motor 72. This motor is. of va the comb roll at a relatively high It is driven through belt 68 to pulley 70 riable speed but drives rate, for example, 400

revolutions per minute as compared with the slow rate of revolution of the feed rolls.

Suitable collecting apparatus is employed for receiving the, individual fibrous elements combed out. of the compressed mass by comb roll 56. Although this may assume various forms, it may conveniently comprise a conveyingv belt 74.

Thus by the present invention there is provided a relatively simple apparatus for feeding fibrous materials such as wood fibers in a continuous, uniform stream substantially free from clumps and flocs. The apparatus is so designed as to be free from difficulties due to jamming, plugging and hanging up which plague the operator of theconventional fiber feeder. Also, it is readily adjustable to accommodate fibrous materials of varying characteristics and to feed them at a selected feed rate.

It is to be understood that the form of my invention herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claims.

Having thus described my invention, 1 claim:

1. A volumetric feeder for fibrous materials comprising av vertical chute for containing and transmitting a quantity of material, the bottom end of the chute having an outfeed opening of uniform width and depth, a pair. of parallel, rotatably mounted, spiked feed rolls stationed side by side below and in close proximity to the outfeed opening of the chute with their axes parallel to the sides of the opening forming its depth for receiving between them material discharged by the chute, the feed rolls having their opposed peripheral surfaces separated by a distance of about one-half the corresponding parallel width of the chute opening and having a diameter which is from two to four times the said corresponding. parallel width of the chute opening, adjusting means for adjusting the spacing between the feed rolls, motor means connected to the feed rolls for driving them in the. feed direction, the chute being proportioned to feed the material at a rate at least equal to the peripheral speed of the feed rolls, the latter thereby engaging the material and compressing it between the rolls to about one-half its original bulk density while advancing it toward the discharge side of the feed rolls, a comb roll rotatably mounted below the feed rolls and operable between the same in the region of fibrous material compression, motor means for driving the comb roll at a rate substantially greater than the feed rolls and sufficient to comb out from the compressed mass of fibrous material substantially individual fibrous elements, and collecting means stationed adjacent the comb roll for collecting the fibrous elements separated thereby.

2. A volumetric feeder for fibrous materials comprisinga chute for containing and transmitting a quantity of fibrous material, the bottom end of the chute having an outfeed opening of uniform width and depth, a pair of rotatably mounted, parallel, feed rolls stationed side by side below and in close proximity to the outfeed opening of the chute with their axes parallel to the sides of the opening forming its depth for receiving between them material discharged by the chute, the feed rolls having their opposed peripheral surfaces separated by a distance which is between A and the corresponding parallel Width of the chute opening and having diameters at least equal to the said corresponding parallel width of the chute opening, motor means connected to the feed rolls for driving them in the feed direction, the chute being proportioned to feed the material at a rate at least equal to the peripheral speed of the feed rolls, the latter thereby engaging the material and compressing it while advancing it toward the discharge side of the feed rolls, a comb roll rotatably mounted between the feed rolls at the discharge side thereof and operable in the region of compression of the fibrous material, and motor means for driving the comb roll at a rate substantially greater than the feed rolls and sufiicient to comb out substantially individual fibrouselements from the compressed mass of fibrous material.

3. A volumetric feeder for fibrous materials comprising a chute for containing and transmitting a quantity of fibrous material, the bottom endof the chute having an outfeed opening of uniform width and depth, a pair of rotatably mounted, parallel, feed rolls stationed side by side below andin close proximity to the outfeed opening of the chute with their axes parallel to the. sides of the opening forming its depth for receiving between them material discharged by the chute, the feed rolls having their opposed peripheral surfaces separated by a distance which is between A and the corresponding parallel width of the chute opening and having diameters at. least equal, to the said corresponding; parallel width of the chute opening, motor means connected to the feed rolls for driving them in the feed direction, thereby engaging the material and compressing it while advancing it toward the discharge side of the feed rolls, a comb roll rotatably mounted between the feed rolls at the discharge side thereof and operable in the region of compression of the fibrous material, and motor means for driving the comb roll at a rate substantially greater than the feed rolls and sufficient to comb out substantially individual fibrous elements from the compressed'mass of fibrous material.

4. A volumetric feeder for fibrous materials comprising a chute for containing and transmitting a quantity of fibrous material, the bottom end of the chute having an outf'eed opening of uniform width and depth, a pair of parallel rotatably mounted feed rolls stationed side by side below and in close proximity to the outfeed opening of the chute with their axes parallel to the sides of the opening forming its depth for receiving between them material discharged by the chute, the feed rolls having their opposed peripheral surfaces separated by a distance less than the corresponding parallel width of the chute opening and having diameters at least equal to the said corresponding parallel width of the chute opening, motor means connected to the feed rolls for driving them in the feeddirection, thereby engaging the material discharged by the chute and compressing it while advancing it toward the discharge side of the feed rolls, a comb roll rotatably mounted between the feed rolls at the discharge side thereof and operable in the region of compression of the fibrous material, and motor means for driving the comb roll at a rate substantially greater than the feed rolls and sufficient to comb out substantially individual fibrous elements from the compressed mass of.

fibrous material.

References Cited in the file of this patent UNITED STATES PATENTS 1,139,345 Conrad May 11, 19 15, 1,331,001 Conrad Feb. 17, 1920= 2,653,353

Herrmann Sept. 29, 19-53 Jam

Claims

1. A VOLUMETRIC FEEDER FOR FIBROUS MATERIALS COMPRISING A VETRTICAL CHUTE FOR CONTAINING AND TRANSMITTING A QUANTITY OF MATERIAL, THE BOTTOM END OF THE CHUTE HAVING AN OUTFEED OPENING OF UNIFORM WIDTH AND DEPTH, A PAIR OF PARALLEL, ROTATABLY MOUNTED, SPIKED FEED ROLLS STATIONED SIDE BY SIDE BELOW AND IN CLOSE PROXIMITY TO THE OUTFEED OPENING OF THE CHUTE WITH THEIR AXES PARALLEL TO THE SIDES TO THE OPENING FORMING ITS DEPTH FOR RECEIVING BETWEEN THEM MATERIAL DISCHARGED BY THE CHUTE, THE FEED ROLLS HAVING THEIR OPPOSED PERIPHERAL SURFACES SEPARATED BY A DISTANCE OF ABOUT ONE-HALF THE CORRESPONDING PARALLEL WIDTH OF THE CHUTE OPENING AND HAVING A DIAMETER WHICH IS FROM TWO TO FOUR TIMES THE SAID CORRESPONDING PARALLEL WIDTH OF THE CHUTE OPENING, ADJUSTING MEANS FOR ADJUSTING THE SPACING BETWEEN THE FEED ROLLS, MOTOR MEANS CONNECTED TO THE FEED ROLLS FOR DRIVING THEM IN THE FEED DIRECTION, THE CHUTE BEING PROPORTIONED TO FEED THE MATERIAL AT A RATE AT LEAST EQUAL TO THE PERIPHERAL SPEED TO THE FEED ROLLS, THE LATTER THEREBY ENGAGING THE MATERIAL AND COMPRESSING IT BETWEEN THE ROLLS TO ABOUT ONE-HALF ITS ORIGINAL BULK DENSITY WHILE ADVANCING IT TOWARD THE DISCHARGE SIDE OF THE FEED ROLLS, A COMB ROLL ROTATABLY MOUNTED BELOW THE FEED ROLLS AND OPERABLE BETWEEN THE SAME IN THE REGION OF FIBROUS MATERIAL COMPRESSION, MOTOR MEANS FOR DRIVING THE COMB ROLL AT A RATE SUBSTANTIALLY GREATER THAN THE FEED ROLLS AND SUFFICIENT TO COMB OUT FROM THE COMPRESSED MASS OF FIBROUS MATERIAL SUBSTANTIALLY INDIVIDUAL FIBROUS ELEMENTS, AND COLLECTING MEANS STATIONED ADJACENT THE COMB ROLL FOR COLLECTING THE FIBROUS ELEMENTS SEPARATED THEREBY.