CA1212596A - Wood chip screening and processing methods and apparatus - Google Patents

Abstract

IMPROVEMENTS IN WOOD CHIP SCREENING AND
PROCESSING METHODS AND APPARATUS
ABSTRACT OF THE DISCLOSURE
A system for separating and classifying whole tree wood chip material comprising essentially wood and bark overs, chips and bark fines which is supplied to a bin or receptaole.
The chip material is augered in a forward direction in a monitored flow longitudinally away from the bin while pass-ing it across a first stationary screen trough system having openings of a size to pass everything, while rejecting the overs. The acceptable chips and fines passed through the first screen trough system are then augered across a second stationary screen trough system having openings of a size to pass the fines to a fines trough, while retaining the acceptable chips. Finally, the acceptable chips are moved forwardly toward a chip discharge location while the fines passed through the second screen trough system are separately collected. The system includes mechanism for diverting chip-ped material unsuited to use in a paper mill, such as chipped tree tops, directly to the fines trough.

Description

1 ¦ Recently various industries, such as the paper-

2 ¦ making industry, are using wood chips produced from entire

3 tree processing, as distinguished from those produced only

4 ¦ from debarked logs. This has been possible since 1970 when

5 ¦ the machine disclosed in U. S. patent No. 3,661,333 was in-~ ¦ troduced to reduce an entire tree with attached limbs and 7 ¦ branches to chips. The tree reduction machine described in 8 ¦ the patent, which can be used in the forest near the tree ~ ¦ felling site~ produces a chip mixture which includes pieces 10 ¦ of relatively small branches and twigs which are not in chip 11 ¦ form, cards, and pieces of bark which may be referred to as 12 ¦ overs, bark and leaf dust, and small chip pieces which may 13 ¦ be referred to as fines, and chips, some with adhering bark, 14 ¦ of a substantially uniform size which are useful in the paper-15 ¦ making and other industries. The overs may be fed to a re-lR ¦ chipper while the fines are used in the energy industry as 17 ¦ a low cost fuel. Quite normally, the trees being processed 18 are those not suited to the production of lumber which have 19 ¦ been "thinned" from existing forest stands to permit the re-20 ¦ maining trees to have unimpeded further growth. Alternatively, 21 ¦ with trees which do contain usable lumber in their lower ex-22 tremities, bucking lengths may be severed prior to the chip-23 ping operation. Previous efforts to resolve the problems ~4 involved with separating the wood chips from the remainder of the material have included the use of vibratory screen appara-26 tus of the type disclosed in U. S. patent 4,351j719.

~8 The present system, as disclosed in U. S. patent 2~ 4,396,501 and the present application, represents another ~0 approach to the separation which is required - which involves ~ "`

.596 1 the augering of the chips across stationary, curvilinear, 2 perforate surfaces at a controlled rate to achieve the ~ separating action, as distinguished from the agitating of 4 flat perforate surfaces. The system disclosed herein may be used as a companion machine to the tree reducing machine ~ in the forest or as a processor at a secondary site, and is 7 particularly designed for large volume operations capable, 8 for example, of processing more than one hundred tons of 9 material per hour at a secondary site.

11 One of the prime objects of the present invention 12 is to design a high-volume system which is extremely effec-~3 tive and efficient in separating the overs and the fines 14 from the useable wood chips.

~ A still further object of the invention is to 17 provide a system which permits an operator to bypass the 1~ overs and useable wood chip augers, and route the products 19 of, for example, tree top chipping, which are for the most part small branches, twigs, and foliage debris, directly to ~l the fines conveyor. The selectable routing system is also 22 useful in the chipping of low quality waste wood of the 23 type which accumulates on the forest floor and is useful as ~4 fuel. Material of this character, which always has been left to rot, may now be very efficiently chipped at the time ~6 paper quality chips are being produced, and used as fuel.

28 Another object of the invention is to design a 3~ machine of the character described which substantially scrubs off and pulverizes the softer adhering bark, but ;~ 121! ~5~6 1 ¦ does not damage the chips - and efficiently processes 2 ¦ the material so rapidly that processing costs are 3 ¦ relatively minimal and great economies in these opera-¦ tions can be achieved.

~ ¦ Still another object of the invention is 7 ¦ to provide a system which deposits the separated 8 ¦ material in segregated piles which can be readily 9 ¦ removed in a high volume operation, or channels it ¦ to separate stations from which it may be delivered 11 ¦ directly to the transport vehicles.

13 ¦ The chipped whole trees, comprising a mix 14 ¦ of wood and bark overs, wood chips including some with ¦ adhering bark, and bark and leaf fines are fed to a lB ¦ receptacle structure which includes a first screen 17 ¦ system, with openings of a size to pass the wood chips 18 ¦ and fines, and retain the overs. An underlying second 19 ¦ screen system has openings of a reduced size to pass ¦ the fines and retain the wood chips, extending at least 21 ¦ partially coextensively with the first screen system.
Z2 ¦ The fines proceed to a conveyor underlying the second 23 ¦ screen system.
~4 1 ¦ Other objects of the invention will become 2B ¦ apparent in reference to the following specification 27 ¦ and to the drawings, wherein:
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~0 1 - 3 121;~9~

1 Figure 1 is a schematic, isometric view illustrating 2 ¦ the system of the invention used at a secondary site loca-3 ¦ tion;
4 ¦ Figure 2 is an enlarged view of a part of the sys-5 ¦ tem illustrated in Figure 1, disclosing the manner in which

6 ¦ it is modularly p.rovidedi

7 ¦ Figure 3 is a partly sectional, isometric view

8 ¦ showing only portions of the device to illustrate part of ~ ¦ the processing operation;
10 ¦ Figure 4 is an enlarged, sectional, elevational 11 ¦ view taken on approximately the line 4-4 of Figure l;
12 ¦ Figure 5 is a fragmentary perspective view illus-13 ¦ trating the construction of the auger flights;
14 ¦ Figure 6 is a schematicj transverse sectional view 15 ¦ illustrating the manner in which the material fills the 1~ ¦ troughs provided by the perforate screens;
17 ¦ Figure 7 is a fragmentary sectional elevational 18 ¦ view disclosing a movable control gate for metering out-flow lg ¦ from the chip mix supply bin;
20 ¦ Figure 8 is a schematic, top plan view illustrat-21 ing a modified method of processing in which the system is 22 used at a forest site, adjunctively to a "whole tree"
23 chipper;
24 Figure 9 is a side elevational view of the modi-fied system, the broken lines indicating alternate positions ~6 of a. gate device;
~7 Figure 10 is an enlarged side elevational view of ~8 the receiving unit disclosing the routing gate in one posi-tion;

~2~ 5~6 1 Figure 11 is a similar end elevational view of the 2 unit;
3 Figure 12 is a top plan view thereo:E; and 4 Figure 13 is a schematic electrical control diagram.

~ Referring first of all to Figure 1, wherein a sta-7 tionary site is somewhat schematically illustrated, the system 8 includes a roadway framework 10, interrupted at lla to provide ~ space for a large capacity surge bin 11 formed with side walls 12 and 13, a front wall 14 and a rear wall 15. The chamber of 1~ the bin may be spanned at its upper end by bracing rods 17.
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13 A section 18 of the roadway may be pivotally sup-14 ported at 19 so that it can be raised by hydraulic cylinders 1~ 20, mounted on framework 10, to the position in which it is 16 shownt to enable a truck 21 to empty a load via its open ~7 rear end to the surge bin 11. The truck 21 will have pro-18 ceeded from a location in the forest where it is loaded with 19 whole tree chip material of the type manufactured by the tree harvesting machine mentioned in the aforementioned pat-21 ent No. 31661,333. A framework 22 is provided on the rais-22 able section of roadway 18 for attachment with the piston 23 rods 23 of the hydraulic cylinders 20. In this way, the 24 huge bin of the truck 21 empties by gravity to the chamber 11, and the material emptied proceeds further by gravity to the ~6 unit generally designated 24, disclosed in Figure 2, which ~7 has a portion which extends beneath the abbreviated front ~8 wall 14 of bin 11 to span the bottom thereof.
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3~ As Figure 2 indicates, the unit 24 may comp:ri.se 1 ¦ three identical modules ~a, 24b, and 24c, supported on a æ ¦ framework 25, each powered by a separate hydraulic pump 3 ¦ and motor unit M in a manner which will later be discussed 4 ¦ in more detail. While three such modules 24a-24c are 5 ¦ shown, it should be understood tha~ the capacity of the ~ ¦ system can be increased by simply adding additional side-7 ¦ by-side modules and, in view of the identity of the modules, 8 ¦ only one of them will be described in detail herein.

gl 10 ¦ As Figures 2 and 3 indicate, each of the modules 11 ¦ includes a rear end wall 26, side walls 27, and an imper-12 ¦ forate trough-shaped bottom wall 28. The upper end of each 13 ¦ module 24 is open and provided in the upper end thereof, 14 ¦ supported by side walls 27, is a screen system comprising 15 ¦ a pair of side-by-side trough-shaped plates 29 and 30 (Fig-~ ¦ ure 3) which are connected in abutting relationship along a 17 ¦ juncture line 31. The trough shaped plates 29 and 30, ex-18 ¦ cept for the portions which extend into bin 11, are provided 19 ¦ with openings 32 which are of a size to pass acceptable wood ~0 ¦ chips and fines, but will reject the overs which may com-21 ¦ prise over-sized chips, twigs, parts of branches and the ~2 ¦ like~ these overs being indicated in Figures 2 and 3 at 0.

24 ¦ Typical acceptable wood chips are in the range of 25 ¦ 3/8 to 7/8 inches square and about 1/8 inch in thickness, ~6 ¦ and the most popular size is the 7/8 x 7/8 chip. Typically, 27 1 the holes 32 will therefore be two inches in diameter.

28 ¦ Provided in each of the sieves or troughs 29 and 30 is an Z~ ¦ auger shaft 33 upon which relatively thin blade, non--~0 ¦ interrupted helical auger flights 34 are provided. It will 5~6 1 be seen from an inspection of Figure 2, that these auger 2 shafts 33 project from the end walls 26.

At their opposite ends the auger shafts are journaled in a front end wall portion 35. To avoid the ~ use of hanger strap bearinys on which the material could 7 "hang up", the shafts 33 are kept as short as possible 8 while still functioning to remove all of the overs from

9 the material which passes through openings 32. Just be-yond the front end of the troughs 29-30, a cross auger 11 shaft 36 is journaled in an overs collection box 37. The 1~ cross shaft 36 has helical flights 38 thereon, and it will 13 be noted that the flights 34 terminate short of the path of 14 the flights 38 so as not to interfere with them as they feed the overs to them. The projecting end 37a of box 37 1~ is open at its bottom side to feed the overs via a vertical 17 trough 38 to a chipper generally designated 39 o~ any suit-18 able type, trough 38 leading to the front face of the typi-19 cal chipper disc 40, shown in Figure 4. The chipper 39 may, as usual, include a front housing wall 41 (Figure 1) and a 21 rear housing wall 42 (Figure 4), along with end walls 43 22 and 44, connected by a curvilinear bo-ttom wall 45 enclosed 23 by housing 45a. A chipper disc 46 of the character dis-24 closed in U. S. patent No. 4,057,192 which may be generally triangularly shaped, mounts on a shaft 47 and has a series 26 of circumferentially spaced openings 48 provided therein.
~7 While three such openings are shown, a fewer or greatex ~8 number of such openings may be provided, and mounted within 2~ the openings 48 in a suitable manner, are chipper knives 49 with cutting edges 49a. Secured to the disc face 46, to 1 make up the composite circular disc system, are segment 2 plates 50, and it is to be understood that in the usual 3 manner portions of openings 51 remain open above the knife 4 edges 49a to enable chips which are cut to pass from the front side of the disc shown in Figure 4, to the rear ~ face thereof.

8 Collecting housings, as shown in U. S. patent 9 No. 4~057,192, or blades as shown in U. S. patent No.

3,861,602, may be provided on the rear of disc face 46 to 11 operate as fans which, when the disc is rotated in the di-12 rection x, shown in Figure 4, will create a high-speed 13 stream of air which will proceed in the direction _ out 14 the discharge chute 52 provided on chipper 40.

1~ As Figure 1 indicates, discharge duct 52 has a 17 horizontally extending portion 53, which terminates in a 18 conventional centrifugal cyclone separator 54 having an lg open upper end 54a, and an open lower end 55. It will be observed that the cyclone 54 is arranged above the sieves 21 29 and 30 at the point where they extend beyond the surge 22 bin 11. The heavier material and chips proceeding from 23 discharge pipe 53 peripherally into the cyclone 54 are Q4 centrifugally separated from the air stream which exits out top 54a, while the solid material falls by gravity to 26 the sieves 30 and 31 for further processing. Thus, the 27 overs are rechipped and useful chips are obtained from ~8 them, as well as fines. The use of the cyclone 54 prevents the material chipped in chipper 40 from blowing al:L over, ~0 and collects it so that it can be re-deposited in the unit 1 24 near the front end thereof so as to be subject to the 2 full line separating action of augers 34.

4 Below the pair of sieves 29 and 30l and axially aligned therewith, is a larger under sieve or screen 56 in ~ ~rough shape, which may comprise a solid sheet of material 7 with openings 57 (Figure 3), the openings 57 being of a 8 size to pass fines, but retain the acceptable chips C.
.~ Typically, the openings 57 will be one-half inch in dia-meter when 7/8 inch acceptable chips are being processed, 11 but may typically range in size from 1/4 inch to 7/8 inches 12 in diameter. The fines F, which -typically are bark with 13 some insubstantial quantity of pulverulent dirt, leaf ma-14 terial and foreign matter fall through openings 57 to the trough-shaped bottom 28.
~6 17 ~ounted within trough 57 is an auger shaft 58 on 18 which continuous helical flights 59 are provided, as shown, 19 the flights 59 being considerably larger diametrally than the flights 34. Typically the flights 34 may have a nine 21 inch diameter with a six inch pitch, while the flights 59 22 may have a sixteen inch diameter with a sixteen inch pitch.
23 The flights 34 will have a speed in the neighborhood of 11 24 to 73 feet per minute, while the flights 59 will have a speed in the neighborhood of 40 to 193 feet per minute.
26 These parameters will get as much auger surface area in ~7 contact with the typical material being processed as 28 possible and provide the best tumbling and turnover action.
~ Typically a chipped material batch proceeding from surge 3G bin 11 will comprise about ten percent overs in volume, 1 ¦ and 25 percent fines in volume, with the balance being 2 ¦ acceptable chips. These can be processed very efficiently 3 ¦ when pairs of auger shafts 33 are provided above an auger 4 ¦ shaFt 58, and the lowex flights are in the neighborhood 5 ¦ of twice the diameter of the upper flights.
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7 ¦ As Figure 1 indicates, each shaft 58, which also 8 ¦ is journaled in end wall 26 and projects considerably be-~ ¦ yond the shafts 33 to journal in an end wall 60, is housed

10 ¦ also by continuations 27a of side walls 27. The sieve ~1 ¦ trough 56 terminates just short of the discharge chute 61 12 ¦ into which it empties. Chute 61 has an open bottom to de-13 ¦ liver acceptable chips to the supply hopper 62 of a portable 14 ¦ conveyor transport system 63, which has an endless conveyor 15 ¦ belt 64 for delivering acceptable chips to the chip pile 65.
1~ l 17 ¦ Typically, if the sieve sections 29 and 30 are 18 ¦ thirteen feet in length, the sievè trough 57 will be on the 19 ¦ order of thirty-six feet in length, and the underlying trough 20 ¦ bottom 28 may be on the order of thirty feet in length. Pro-21 ¦ vided in the trough-shaped bottom 28 is an auger shaft 66 on 22 which continuous helical auger flights 67 are mounted to 23 transport the fines forwardly to a discharge trough 68 to ~4 which they are emptied. The trough 68 includes an auger shaft 69 with continuous helical flights 70 supplying the ~6 acceptable chips to a unit, for example, of the character ~7 shown in U. S. patent 3,979,152 which blows them out the ~8 discharge pipe 71 to a fines pile 71a.

As Figures 5 and 6 indicate, the flights 34 are 1 the interrupted variety in which a tab or hook portion 2 72, cut from the flights, is turned at substantially a 3 right angle to lie axially parallel to the axis of the ~ auger shaft 33. Each tab 72 remains connected with the S flight 34 along the side of the aut-out opening 72a formed ~ therein, on the downstream side of opening 72a considering 7 the direction of rotation z of the auger shafts. The flights 34 and 59 are positioned to leave a minimum clear-g ance less than the chip thickness between the flights and 1~ the parabolic screens 29, 30 and 56. This aids in prevent-

11 ing the shielding of openings 32 and 57 and also promotes

12 the removal of any bark adhering to the chips. Over the

13 length of trough system 29, 30 all the chips being conveyed

14 encounter the screen openings. Because the screens 29, 30 and 57 are parabolic, the separation is enhanced while per-16 mitting their easy removal and replacement.

18 Provided, as shown in Figure 7, to control the 19 flow of chipped material, is a metering gate 73. The swingable gate 73, which may be hingedly connected to the 21 bottom of abbreviated front wall 14, is powered and held 22 in posi~ion by hydraulic cylinders 74 mounted on brackets 23 14a on the front wall 14 of surge bin 11. The piston rod 24 75 of cylinder 74 swings the gate 73 outwardly about its hinge point 77 on front wall 14 to selected positions.
~5 27 The shafts 33, 58 and 66 may readily be driven ~8 in the same direction of rotation by the rotary hydraulic motor 26a provided for each module. A chain 80 can be trained around sprockets 81 on the shaft 33, and around a I
I
1 ¦ drive sprocket 82 on the motor shaft which drives shaft 2 ¦ 58. A second chain 83, powered by the motor shaft, may 3 ¦ be trained around a sprocket 84 provided on auger shaft 6~.
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5 ¦ The position of gate 73 is such as to create ~ ¦ sufficient flow from the bin 11 to achieve a material fill 7 ¦ MF ~see Figure 6), which is in the neighborhood of thirty 8 ¦ percent of the auger diameter. With the direction of ro-9 ¦ tation in the direction z, the chips are conveyed in a 10 ¦ tumbling helical path by the flights 34 and substantially ~1 ¦ form an agitated bed B which leaves upstream side portions 12 ¦ 78 of the screen troughs 29, 30 substantially uncovered.
13 ¦ The tabs 72 tend to propel the material through the holes 14 ¦ 32 on the portions 78 of the sides of the troughs 29, 30 l~ ¦ which are not covered by the material. The tabs or hooks 1~ ¦ 72 further agitate the chips to allow the acceptable chips 17 ¦ to more easily and freely flow through the openings 32 in 18 the area of screens 29, 30 covered by bed B. Still a fur-19 ther function of hooks 72 is to keep the openings 32 from filling up with overs, and the hooks 72 accomplish this by 21 literallv pulling the overs from holes 32 and keeping them 22 moving.

24 The flights 34 move the bed of material B con-tinuously across the perforate surface of the sieve with ~6 an action which has some scrubbing effect in the sense that, ~7 while the acceptable chips remain undamaged, pieces of bark ~8 and dirt adhering to them tend to be removed. The speed of shafts 33 is such, in terms of feet per minute and pitch of the continuous auger flights 34, that pencil-shaped overs 1 do not drop through the openinys 32, the speed being too 2 fast to permit them to exactly line up with the openings ~ in their tumbling action. The overs, as indicated ear-4 lier, proceed to the cross auger blades 38, then drop by gravity through chute 38 to the chipper 40 which reduces ~ them in size and delivers them to the cyclone separator 54, 7 from whence they drop once again to flights 34. The unit 8 24 operates very efficiently when the total volume carried ~ between the flights 34 (i.e., between 360 degree separated portions) is approximately one-half a cubic foot of chips 11 by volume.

13 Acceptable chips and fines are collected on 14 trough screen 56 which similarly will be only partially filled (i.e., about twenty percent) so that a free area 1~ of curvilinear screen at 56a (Figures 3, 6) is similarly 17 left on the downstream side of sieve 56. As indicated pre-18 viously, the acceptable chips are discharged by the flights 19 59 at the chute 61 to the dished conveyor belt 68 which transports them to the chip pile 65. The fines which pass 21 through openings 57 are discharged via auger flights 67 22 to the blower unit which delivers them via pipe 71 to the 23 fines pile 71a.
~4 It has been determined that the system described 26 removes substantially one hundred percent of the fines 27 which means a higher percentage of the bark than previous 28 systems, particularly when hardwoods and pine are being processed. This is important in the paper-making industry where bark particles interfere with the chemistry of paper-i;$~

1 making. In the tumbling action in sieves 29 and 30, the 2 fines tend to proceed to the bottom and superior separation 5 ¦ results from the chipped material being conveyed across a ~ ¦ stationary screen surface and the superior tumbling action 5 ¦ which is obtained, rather than vice versa.
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7 ¦ To increase the tonnage of material handled on an 8 ¦ hourly basis, it is merely necessary to add additional side-~ ¦ by-side modules 24, and it is thought that such a system 10 ¦ could process in the neighborhood of six hundred tons of 11 ¦ material per hour.

13 ¦ In Figures 8-12, a modified system for processing 14 ¦ whole tree material in the forest is disclosed and includes

15 ¦ a whole tree chipper vehicle of the character disclosed in

16 ¦ the present assignee's U. S. patents 3,661,333 and 4,078,590,

17 ¦ for example. For purposes of convenience, it will be assumed

18 ¦ that the screen system disclosed is that previously disclosed

19 ¦ in Figures 1-7 and for that reason identical numbers have

20 ¦ been used to identify like elements and the description will

21 ¦ not be repeated, except to comment on structure which is not

22 ¦ included in the previous description. For purposes of

23 ¦ clarity, only one module has been illustrated, and normally ~4 ¦ only a single module would be used on a wheel mounted ve-25 ¦ hicle to service one chipper vehicle in the field.
~6 27 ¦ Referring now to U. S. patent 4,078,59~ (and ~8 ¦ Figure 8 hereof) for a better understanding of the chipper ¦ unit per se which is supported on the vehicle, it will be ~0 noted that the disc type chipper C, provided with:in chipper 1 ~ using H on chipper vehicle 99, has a tangentially extend-2 ing outlet DS for discharging chips from the chipper hous-3 ing H. Material processed through the chipper C is blown 4 out the outlet DS in an air stream created by fan blades on the back of the chipper disc in the usual manner (see ~ U. S. patent 3,861,602, for instance). The chipper vehicle 7 99 also includes a telescoping boom 100, with grapple arms 8 G thereon for gripping trees T and placing them on the feed 9 deck 101 of the chipper, from which they are fed into the mouth of the chipper housing H by mechanism such as that ~1 described in the aforementioned U. S. patents. Where pos-12 sible to buck saw logs from the boles of the trees T, first 13 of all, this can be accomplished before the trees T are 14 grasped by the chipper boom grapple arms G.
16 The outlet chute DS extends laterally as shown 17 to align with a receptacle or bin generally designated 102, 18 provided on the screen vehicle 103. Vehicle 103 is shown lg as supported on wheels W and a front retractable jack de-vice J. Of course, in Figure 8, the vehicles 99 and 103 21 are shown only schematically, and Figure 9 better illus-22 trates the receptacle 102 which includes a cyclone separator 23 104, having an inlet chute 105, with open mouth 105a, aligned ~4 to receive the air stream with its entrained material from chipper housing outlet DS. As with separator 54, the upper ~6 end of circular cyclone separator 104 has a top pipe opening 27 106 (Figure 12), provided by pipe 106a which is open at its 28 bottom also, to permit egress of the air after the solid 2~ material has been separated from it in the cyclone 104.
~ Cyclone 104 is affixed by gusset plates 104a to a flange lZ12~;96 1 104b, which rides on supp~rt r~l ers 107 on receiving hous-2 ¦ ing 108 so that it is easily adjusted to various rotary 3 ¦ positions. Support brackets lO~a fixed to rectangular 4 ¦ housing 108, which is open to the cyclone separator 104 5 ¦ at its upper end and is open also at its lower end, sup-~ ¦ port the rollers 107.

8 ¦ The discharge from open-bottomed housing 108 may 9 ¦ be to a vertical chute 109 formed by extensions 27a of side 10 ¦ walls 27, a rear housing lO9a, and a rear wall 26 which 11 ¦ closes the ends of the compartments in which auger shaEts 12 ¦ 33 and 58 operate~ The fi.nes trough 28 projects beyond 13 ¦ wall 26 to underlie the vertical chute 109, wall 26 func-14 ¦ tioning as the end wall for chip trough 56 and overs trough 15 ¦ structure 29-30 to close them off from chute 109. Also 1~ ¦ shaft 66, with its auger flights 67, is extended to under-17 ¦ lie the chute 109 which is open at its lower end to deliver 18 ¦ material to the trough 28. Wall 26, it will be noted in 19 ¦ Figure 9, extends downwardly approxi~ately in a plane bi-20 ¦ secting housing 108.

22 ¦ Fixed on a pivot shaft 110, journaled in suitable 23 ¦ bearings 111, supported by housing 108, is a deflector or ~4 ¦ director gate 112 which is pivotal between the positions 25 ¦ shown at 112a and 112b in Figure 9, to respectively direct ~6 ¦ the solid material outflow from cyclone 104, respectively, 27 ¦ to the open upper end of trough structure 29-30, or alter-28 ¦ natively to the upper end of vertical chute 109. The gate 2~ ¦ 112 is under the control of the operator in the cab C-l of ~ ¦ the chipper vehicle 99, and a typ:ical control circuit is 1~ Z596 1 ~ illustrated in Figure 13. The double acting solenoid con-2 ¦ trolled fluid operated cylinder 113 for operating gate 112 3 ¦ is shown in this Figure as having advance and retract sole-4 ¦ noids 113a and 113b respectively in circuit lines a and _, 5 ¦ which have push button opexated switches S-l and S-2 therein ¦ for energizing the solenoids 113a and 113b selectively. The 7 ¦ shaft 110 is shown as pivotally connected to the piston rod 8 ¦ 114 of cylinder 113, and cylinder 113 is shown as pivotally ~ ¦ connected to brackets 115 provided on side wall 27.

~1 ¦ The operator in cab C-l controls the discharge 1~ ¦ from cyclone 104. When the chipper C, via chute D~, is 13 ¦ feeding tree tops or other material which is unsuited to 14 the making of pulp chips, the operator will activate cylin-der solenoid coil 113b to place gate 112 in the 112a posi-1~ tion and direct the material from cyclone 104 directly to 17 chute 109 and the fines trough 28. At this time coil 113a 18 will, of course, be deenergized. Otherwise, advance sole-19 noid coil 113a will be energized (with coil 113b deener-gized) to move the gate 112 to the 112b position, such 2~ that the solid material separated by cyclone 104 is fed 22 directly to the top screen structure 29-30.

~4 As Figure 8 indicates, the pulpwood chips from trough 56 can be blown to a van V-l (instead of pile 65) 26 by a blower 85 for trucking to the paper mill, and the ~7 output from conveyor 67 can be blown via a blower 86 to a van V-2 (instead of pile 71a) for trucking to a plant which burns them as a source of energy. The motive power for ~0 driving shafts 33, 58, and 66, and for operating the blower ~;~?~596 1 fans of blower assemblies 85 and 86l is supplied by engine 2 E.
3 It is to be understood that the drawings and 4 descriptive matter are in all cases to be interpreted as merely illustrative of the principles of the invention, ~ rather than as limiting the same in any way, since it is 7 contemplated that various chang~s may be made in various 8 elements to achieve like results without departing from g the spirit of the invention or the scope of the appended c ims.

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Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OF PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Apparatus for separating and classifying chipped whole trees comprising a mix of wood and bark overs, wood chips including some with adhering bark, and bark and leaf fines, comprising:
a. a whole tree chipper;
b. a vehicular frame;
c. receptacle means thereon for receiving chipped whole tree material from the chipper;
d. a first screen system, with openings of a size to pass the wood chips and fines, and retain the overs, mounted on the frame to receive the mix from the receptacle means;
e. an underlying second screen system on said frame, with openings of a size to pass the fines and retain the wood chips, extending at least partially coextensively with said first screen system;
f. a conveyor trough on said frame for receiving the fines underlying the second screen system; and g. means for directing the chipped whole tree ma-terial received by said receptacle means selectively to the first screen system or the fines conveyor trough.

2. A method of separating and classifying chipped whole trees comprising a mix of wood and hark overs, wood chips including some with adhering bark, and bark and leaf fines, which is produced by a whole tree chipper compris-ing the steps of:
a. receiving chipped whole tree material from the chipper;
b. passing said material over a first screen system with openings of a size to pass the wood chips and fines through said first screen system, and retain the overs, while rubbing bark from the chips;
c. passing the material passed through said first screen system over an underlying second screen system with openings of a size to pass the fines, and retain the wood chips, while rubbing bark from the chips;
d. receiving the fines passed through the second screen system on a fines conveyor; and e. by-passing chipped tree top material or other material unsuited to the desired use directly to the fines conveyor.

3. Apparatus for separating and classifying chipped whole trees comprising a mix of wood and bark overs, wood chips including some with adhering bark, and bark and leaf fines which is produced by a whole tree chipper, comprising:
a. a vehicular frame;
b. a bin comprising a cyclone separator and a under-lying discharge housing section, mounted thereon for receiv-ing chipped whole tree material from the chipper;
c. a first screen system with openings of a size to pass the wood chips and fines and retain the overs, mounted to only partly underlie the housing section and receive the mix from the housing section;
d. an underlying second screen system with open-ings of a size to pass the fines, and retain the wood chips, extending at least partially coextensively with said first screen system;
e. a conveyor trough for receiving the fines under-lying the second screen system; and f. means for directing the chipped whole tree material received by said receptacle means selectively to the first screen system or the fines conveyor trough.

4. The inventive apparatus of claim 3 wherein said means for selectively directing the material includes a bypass housing adjacent said screen systems and conveyor trough, also partly underlying said housing section; a gate mounted in said housing section to swing from a posi-tion in which it blocks flow to said bypass housing and directs it to said first screen system, to a position in which it blocks flow to said first screen system and di-rects it to said bypass housing; and motor and switch mechanism for operating said gate.

5. Apparatus for separating and classifying chipped whole trees consisting essentially of a mix of wood and bark overs, chips, including some with adhering bark ma-terial, and bark and leaf dust, comprising:
a. bin means;
b. a module comprising first, stationary, para-bolic screen trough systems with rotary auger conveyors therein extending below the bottom of the bin and for-wardly beyond the bin in a longitudinal direction, the bin having opening means to pass the outflow from the bin and the trough systems including screen openings of a size to pass everything but the overs;
c. an overs collection and discharge station at the front end of said module;
d. the module also having a second stationary screen trough system with a rotary auger conveyor therein extending beneath the first trough system from the bin means forwardly and forwardly out beyond the overs col-lection and discharge station, the second trough system having screen openings of a reduced size relative to said previously mentioned screen openings to pass fines while retaining acceptable chips; and e. a drive for the module connected with the auger conveyors in the first and second trough systems.

6. The apparatus of claim 5 in which a movable wall forms a portion of the bin means along the upper side of the bin opening means; means mounts the wall for movement from a maximum flow restricting position to a minimum flow restricting position; and actuatable means is provided for moving and retaining the wall.

7. The apparatus of claim 6 in which said wall is hinged to said bin means along its upper edge and power cylinder means is operable to swing it upwardly away from said bin means.

8. The apparatus of claim 5 in which said module has an underlying, longitudinally extending, imperforate, parabolic third trough system with an auger conveyor therein receiving fines from said second trough system, and the drive means for the module drives this auger con-veyor as well.

9. The apparatus of claim 8 in which the said third trough system terminates short of the front end of the second trough system and cross conveyor means is provided to discharge the fines collected therefrom.

10. The apparatus of claim 5 in which the outflow from the bin means is correlated with the linear convey-ing rate of the auger conveyors of the first trough systems to provide a rolling bed of the mix therein which so occupies the first trough system as to leave exposed screen surface on the rotary downstream side of the auger conveyors.

11. The apparatus of claim 10 in which axially ex-tending projections are provided on the helical flights of the auger conveyors to rotate therewith and function to propel chips through the exposed screen openings while hooking out elongate overs which should not proceed through the openings.