SE1951555A1 - An apparatus and a method for feeding fibrous material for dewatering - Google Patents

Abstract

This invention relates to a method for feeding of raw material out of a supply chute (10) and also a supply chute for a dewatering press, comprising a container body (10) having an upper part (10A) with an inlet (101) and a lower part (10B) with an outlet (117), a bottom portion (114) and a supply arrangement (11) arranged to feed raw material along the bottom portion (114) out through the outlet (117), characterised in that said feeding arrangement comprises a plurality of parallelly arranged screw feeders (11A, 11B, 11C) along said bottom portion (114), and that said bottom portion (114) has a length (L 10b) in the feeding direction that is larger than the corresponding length of the upper portion (10b) of supply chute.

Description

AN APPARATUS AND A METHOD FOR FEEDING FIBROUS MATERIAL FORDEWATERING FIELD OF THE INVENTION The present invention relates to an apparatus and a method in Which f1brous material isdewatered in a nip formed between rolls and more specifically an apparatus and a method for feeding f1brous material for dewatering.BACKGROUND OF THE INVENTION In order to use f1brous material as a source of energy, e. g. saw dust, wood chips, etc, itcan be dewatered and subsequently used as fuel. To remove water from the f1brousmaterial, wood chips, it may be subj ected to heat that causes moisture in the wood chipsto evaporate. However, such methods are time-consuming and require large amounts ofenergy which makes such methods less effective in terms of energy economy. A methodwhich is more economical in terms of energy economy is to dewater the f1brous material by means of compression.

In an article published 2010 by “ScienceDirect”, Dewatering of high-moisture woodchips by roller compression method (Takahiro Yoshida, Hiroyuki Sasaki, TsutomuTakano and Osamu Sawabe), a method of dewatering wood chips by roller compressionwas disclosed. In that article, a method was described in which wood chips werecompressed between rolls. The article discloses an apparatus with a primary and asecondary unit that both included rollers. The secondary unit had a lower roller with ho les having a diameter of 6 mm that were intended to allow squeezed-out water into anaspiration fiannel attached inside the roller. The water was reportedly expelled by anexhaustion fan attached to the back of the apparatus. A stainless steel wire mesh beltaround the lower roller allowed water to flow from the chips to the ho les. The chipsincluded cedar and cypress chips. Wood chips were dewatered at pressures of 10, 20and 30 MPa. It was found that roller compression can remove water from wood chips with low energy consumption.

GB 2090954 discloses a method and an apparatus in which wood chips are dewatered between two endless conveyors between which the wood chips are squeezed. One of the conveyors is a perforated conveyor and a suction means may be provided for applying a reduced pressure or vacuum to the underside of the perforated conveyor.

When compression has been used to dewater wood chips, the effect has not always metexpectations. From WO20l4/033 156 there is known an improved apparatus in whichdewatering of wood chips is carried out by means of compression. The apparatuscomprises a first roll and a second roll that form a nip in which water can be pressed outof the raw material, e.g. wood chips. An endless perrneable conveyor is arranged to pass through the nip and carry the raw material through the nip.

In order to achieve efficient dewatering, it is necessary to provide for a supply of thef1brous material that is reliable and well adapted to the dewatering device. Variousexamples of supply arrangements are known. However, most of them suffer from one or more disadvantages, e. g. complexity, lack of reliable supply, relatively costly, etc.DISCLOSURE OF THE INVENTION It is an object of the invention to provide a supply chute and a method that is improvedin at least one aspect, which is achieved by a supply chute and method respectively as defined in the independent claims.

Thanks to the invention a reliable and efficient supply of f1brous material may be obtained.According to further aspects of the invention the supply chute further includes: - That the bottom portion is arranged with at least one adjustment device enablingadjustment of the position of the outlet of said bottom portion, which providesthe advantage that adjustments may be achieved for improved supply, whereinpreferably said bottom portion is supported by support members arranged toprovide for an adjustable angle of said bottom portion in relation to a horizontalplane, wherein more preferred said support members comprise a rear supportmember that is pivotally attached to said bottom portion, which provide theadvantage that weight measures may be obtained and that a front supportmember is arranged to provide for adjustable height of said outlet, and/orpreferably that said bottom portion (l l4) is adjustably, slidably supported by being mounted on a movable support plate - That a front support member of said bottom portion is provided with a weightmeasurement means, which provides the advantage that a good control of supplyof fibrous material may be achieved.

- That each screw feeder (11A, 11B, 11C) comprises a shaft (110) driven by atleast one motor (118) at one end opposite to the other end that is positionedadjacent said outlet (117) and having a helical blade (111) arranged around saidshaft (110), which provides the advantage that an improved control of supply offibrous material may be achieved thanks to the ability to independently controleach motor. - that the bottom portion includes screw position members arranged to stabilisethe position of each screw feeder, wherein preferably said screw positioningmembers are in the form of longitudinally divided pipe elements having an innerdiameter adapted to the diameter of the helical blades, which provides theadvantage that an improved reliability of supply of fibrous material may beachieved.

- That the shaft of the screw feeder is merely supported by bearings adj acent thedriven end, which provides the advantage that a less complex arrangement is achieved and that less possibly j amming parts/devices exist.

Further beneficial aspects are evident from the method claims and also from the detailed description.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows a perspective view from above of an embodiment of a machine arrangeda plurality of novel aspects.

Figure 2 shows a side view from of the machine shown in Figure 1.

Figure 3 shows a view from above of the machine shown in Figure 1.

Figure 4 shows a longitudinal vertical cross-sectional view of the machine shown inFigure 1 to Figure 3.

Figure 5 shows some features of an adjustment and control arrangement of the nip inaccordance with an aspect herein.

Figures 6 shows some features of a roll shaft in accordance with another aspect.

Figures 7 and Figure 8 show some features of a novel roll arrangement in accordancewith a fiarther aspect.

Figures 9, Figure 10, Figure 11 and Figure 12 show some features of a novel adjustmentand control arrangement of the front roll in accordance with an inventive aspect.Figure 13 shows a perspective view illustrating an exemplifying raw material supplysystem.

Figure 14 shows some features of a novel support structure in accordance with a stillfurther inventive aspect.

Figure 15 shows a perspective view illustrating an exemplifying support structure.Figure 16 shows a plan view of the exemplifying support structure.

Figure 17 shows a first cross-sectional view of the exemplifying support structure.Figure 18 shows yet another plan view of the exemplifying support structure.

Figure 19 shows a second cross-sectional view of the exemplifying support structure.

Figure 20 shows a third cross-sectional view of the exemplifying support structure.

DETAILED DISCLOSURE OF THE INVENTION With reference to Figure 1, Figure 2, Figure 3 and Figure 4 there is shown differentviews of an apparatus 100 for dewatering fibrous material, e.g. wood chips, comprisinga plurality of inventive aspects. It is to be understood that each of the different aspectsmay be the subject for its own protection, e.g. by the filing of one or more divisional applications.

The apparatus 100 may comprise a basic support frame 8, carrying different modules ofthe apparatus 100. It is evident for the skilled person that there is no absolute need for abasic support frame 8. In the shown example the apparatus comprises such a basicsupport frame 8 supporting a supply chute 10, a band 35, a levelling out device 2, aband adjustment and control arrangement 3, a front roll 40 and a pair of rolls 41, 42 thatform a nip N arranged in a support structure 6 and an adjustment. A pressure adjustingarrangement 5 for adjustment and/or control of pressure in the nip N may suitable bearranged to force one of the rolls 41 in the nip N against the other 42 such that the nip N is loaded and raw material, e.g. wood chips that pass through the nip N will be compressed by the force in the nip N. Throughout the present disclosure, the front roll 40 may be referred to as a first roll 40 or vice versa.

The band 35 may be a feeder band, and endless band, an endless conveyer belt, a transfer belt or the like.

Each roll 41, 42 in the nip N is driven by a motor 410, 420, which also will assist indriving the band 35. Also, a rear roll 43 may be driven by a motor 430 to assist indriving the band, at least initially prior to a forrning a compressed mat in the nip N.Through the present disclosure the rolls 41, 42 may be referred to as an upper roll 41and a lower roll 42, respectively. Sometimes, the upper roll 41 is referred to as a secondroll 41 and/or the lower roll 42 is referred to as a third roll 42. Moreover, the rear roll 43may be referred to as a fourth roll 43. A pressure in the nip N may typically be 40-200tons, preferably 50-150 tons.

In case of dewatering wood chips, larger wood pieces have previously been cut intowood chips that are to be dewatered in the inventive machine. The wood that has beencut to wood chips may be, for example, trunks from trees, branches of trees or rootsfrom trees. In many practical applications, the wood chips may be of a size on the orderof about 5mm - 20 mm (length, thickness, width) but other dimensions are alsopossible. It should be understood that the raw material may vary as already mentioned,e. g. also be saw dust (i.e. smaller than wood chips), pieces of wood (such as small twigs) that are already so small that they need not be cut into smaller pieces, etc.

The apparatus may comprise the band 35 on which the raw material can be transportedinto the nip N. If chips are to be processed, they are preferably spread on the band 35 toform at least 2 layers on top of the band 35, preferably 2-5 layers, to form a relativelytight mat, i.e. substantially without open through holes, in order to achieve an efficientdewatering of all individual wood chips. In some applications it may be benef1cial touse a band 35 that is perrneable to water and forms an endless conveyor, i.e. a loop,around a front roll 40 and a rear roll 43 and is arranged to pass through the nip N such that the endless band 35 can carry raw material through the nip N.

The band 35 may preferably be a metal band/metal belt, but different metal materialscan be considered. Preferably, the band 5 is a stainless-steel belt (band). For example, amartensitic stainless-steel belt, preferably a precipitation hardened steel having arelatively high strength (e.g. above 1500 MPA) and hardness (e.g. above 450 HV5), e.g.a belt grade made of low carbon, martensitic precipitation hardened, stainless steel. Theskilled person may consider What other metal materials that could possibly be used,bearing in mind that a suitable metal material should be able to resist Wear and be strong enough to allow high pressing forces to be used.

One or a plurality of the rolls 40, 41, 42, 43 may be a drive roll/s that drives the band35.

The choice of material and dimensions for the band 35 partly depend on the desiredqualities of the conveyor. The conveyor must have a certain minimum strength andsome ability to resist Wear and abrasion. At the same time, it should be flexible andsufficiently perrneable to Water. It has been found that the endless conveyor maysuitably be a steel band With a thickness in the range of 0.5 mm - 2.5 mm, preferably athickness in the range of 0.8 mm - 2 mm. Suitably, the band 35 has perforations With adiameter in the range of 0.5 mm - 5.0 mm, preferably in the range of 1.0 mm - 3.0 mm.Suitably, the open area of the band is in the range of 5% - 50%, preferable an open areain the range of 10% - 30 % and even more preferred an open area in the range of 15% - %.

Thereby, a good perrneability to Water is achieved While the endless conveyor may stillhave suff1cient strength. The perforations 15 may have a circular (round) shape and arepreferably positioned according to an equilateral triangle hole pattem. A band 35 Withsuch perforations may have a good perrneability to Water, and also assists in movingWood material through the nip N thanks to the combination of a great number ofrelatively sharp “grabbing” edges (formed by each hole) that have a high strength.

Hence, these features assist in enabling the raW material to be moved into and through a nip Nl where the high linear load may otherwise cause difficulties. Therefore, the perforations can contribute to increasing the output of the inventive machine.

In order to improve durability of the band 35 it may be beneficial to use a largerdiameter DT of the tuming rolls 40, 43 than the diameter DN of the rolls 41, 42 in theNip, since fatigue of the band 35 is related to bendability. The thicker the band thelarger must the diameter DT of the tuming rolls 40, 43 be to obtain same lifeexpectancy. Since the band 35 must have a certain thickness to withstand the forcescreated in the nip, it is therefore norrnally an advantage to combine as mentioned above, to combine good strength, compactness and efficiency.

The band 5 may be driven at a speed in the range of 0.5 m/s - 5 m/s, preferably a speedin the range of 0.8 m/s - 3 m/s. This speed is suitable for effective dewatering. Atspeeds that are too high, there is not time enough for the raw material to becomesufficiently compressed. At speeds that are too low, the production rate will beunsatisfactory. In one embodiment contemplated by the inventors, the machine may beoperated at a speed of about l m/s, to produce about 60-90 n13/hour, when supplying anabout 30 mm thick mat into the nip N, implying approx. 20 wet ton per hour at 50% MC (moisture content).

As already mentioned, the wood material is preferably supplied into the nip forrning atleast 2 layers on top of each other, if wood chips preferably 2-5 layers, if saw dustpreferably l0-50 layers, to form a relatively tight mat, i.e. substantially without openthrough holes, in order to achieve an efficient dewatering of all individual woodparticles, which mat in an uncompressed condition has a thickness in the range of l5- l00 mm, more preferred 30 -60 mm.

A linear load can be applied in the nip N which is in the range of 400 kN/m - l500kN/m, preferably in the range of 500 kN/m - 1000 kN/m. Such a force is sufficient foreffective dewatering in many realistic cases. Here, it should be added that the required pressure may vary depending on the type of raw material.

In many practical applications, the nip N may have a gap (distance between the press rolls 41, 42) Which, during operation, may be on the order of about lmm - 10mm, preferably about 3 mm - 6 mm depending on the type of raW material and other factors.

Other dimensions are also possible.

As shown in Figure 4, the levelling out device 2 may include a rake, Which may evenout and/or smoothen out the fibrous material over the band 35, e. g. in the transversal and/or longitudinal direction relatively a moving direction of the band 35.Thanks to the machine, fibrous material, e.g. Wood chips, can be deWatered Withoutexcessive reabsorption of Water after the press nip and clogging of the perforations through Which Water is sucked out is reduced.

In the table there is shown that very positive results may be achieved by means of the invention.MCTest Start MC Finish Other[NY] [%] [%]For reference only to be used as starting MC forrest of the samples. Material Was not processed.Reference Sample Was dried for 24 h in oven in l03i2 °C l 63,6 63,6 to determine starting MC.For reference only to be used as starting MC forrest of the samples. Material Was not processed.

Reference Sample Was dried for 24 h in oven in l03i2 °C 2 64,8 64,8 to determine starting MC. l 63-65 35,1 Pressed once 2 63-65 36,l Pressed oncePressed once then impregnated With cold oil 3 63-65 25,7 and then pressed again.

Pressed once then impregnated with cold oil 4 63-65 26,4 and then pressed again.

Pressed once then impregnated with cold oil 63-65 24,6 and then pressed again.

Pressed once then impregnated with cold oil,pressed again, then impregnated with hot 6 63-65 18,1 (temperature 200 °C) oil and pressed again.

Pressed once then impregnated with cold oil, pressed again, two cycles with impregnation ofhot oil (temperature 200 °C) and pressing to get7 63-65 13,4 rid ofoil.

It is foreseen that this application may be the subject matter for numerous divisionalapplications, having claims focusing on different aspects of the inventive concept, e. g. one focusing on the aspect of A further benef1cial result of the invention is that the processed material will be muchsofter than the raw material (e.g. wood chips) and indeed become spongy. Thanks tothis outcome the processed material will be easier to handle in many situations, e. g. inconnection with baling. Test have shown that bales may easily be produced having a density above 1000 kg/m3.

Moreover, the fiber material will also become partially def1brated, which may providesignificant advantages, e. g. in connection with pulp production, especially MechanicalPulp, by reducing the subsequent need of treatment (chemicals and/or power) to achieve suff1cient def1bration.

Although the inventive method and apparatus is mainly described for treatment of woodchips it is evident that it may also be used for similar purpose for treatment of other materials, e.g. sawdust, bark, hog fuel, etc. Further the inventive apparatus may also be used for other purposes than dewatering, e. g. it may also be used for compressingalready dried wood chips, i.e. for densification of the chips. Very dry wood chipshaving a water content of 12% or less do not spring back very much when they arecompressed. This can be used to increase the density of wood chips such that the woodchips become less bulky. The compressed wood chips may then be transported moreeasily from one place to another. Such compressed wood chips may be bumed toproduce heat. For the purpose of compressing already dried wood chips, the endless conveyor need not be perrneable, and the suction box would probably serve no purpose.

One main advantage of the invention lies in its good capacity for dewatering woodchips. In a test carried out by the inventors, wood chips having a moisture content (MC)of 55-65% were dewatered down to a water content of 28-35%, wherein of course a lower starting MC will help to reach a lower end MC, as is presented the table below.

Final StartingMC MC35,8 6535,2 6434,7 6334,l 6233,6 6l 33 60 32,5 5931,9 583l,4 5730,8 5630,3 55 Now describing one of the novel inventive aspects of the infeed arrangement as best shown in Figure 2 and Figure l3. 11 Figure 5 shows a detailed perspective view of the upper roll 41 of the apparatus 100 fordewatering a f1brous material 2. As mentioned, the apparatus 100 comprises the upperroll 41 and the lower roll 42 that forrn the nip N in which water is pressable out of thef1brous material 2.

The upper roll 41 has two ends 541, 542. The upper roll 41 typically has an evencylindrical surface, wherein the upper roll 41 may be referred to as an even roll 41. Eachend 541, 542 of the upper roll 41 is mounted in a respective bearing 55. The respectivebearing 55 is eccentrically located at a respective location within an eccentricallypositioned mounting hole 540 of a respective circular collet 54, wherein the respectivecircular collet 54 is rotatably mounted in a respective circular mounting frame 600 of asupport structure 6 of the apparatus 100. The respective location may be measured fromthe center of the respective circular collet 54, e.g. in the radial direction from the center.A respective transmission 50 at said each end 541, 542 is arranged to extend or retract arespective lever device 53 to rotate the respective circular collet 54 in the respectivecircular mounting frame 600. The transmission 50 may be a worrn gear mechanism orthe like. A distal end of the respective shaft 520 is connected to the respective circularcollet 54, e. g. rotatably connected, and a proximal end of the respective shaft 520 ismounted in the respective transmission 50, which is mounted at the support structure 6.The respective circular collets 54 are arranged to rotate the respective locations of thetwo ends 541, 542 in phase and synchronized, whereby due to rotatability of therespective circular collets 54 a distance between the upper and lower rolls 41, 42 at thenip is adjustable. In this manner, it is ensured that the distance at the nip remains constant along the longitudinal direction of the lower roll 42.

Preferably, a common input shaft 51 is connected between the respective transmissions,wherein the common input shaft 51 is arranged to cause the respective transmissions 50,such as linear drive mechanisms, to extract and retract the respective beams 520 in phase and synchronously.

In one example, the respective drive mechanism 50 is fixedly mounted at the support structure 6. The respective beam 520 is rotatably connected to the respective circular 12 collet 54 via a respective arm 533. In another example, the respective drive mechanism 50 is rotatably mounted at the support structure 6.

In the shown exemplified embodiment in figure 5, the pressure adjusting arrangement 5comprises a plurality of interacting members 50, 51, 52, 53, 54 on each side of theupper roll 41. Merely one side will be described in the following. The transmission 50 isin the form of a gear box 50 that transmits torque/rotation from the common input shaft51 to an output shaft 52. Accordingly, via the interacting gear wheels (not shown)within the gearbox the input torque will be transmitted to the output shaft 52. A drivemember 51A is connected to the common input shaft 51 to provide for the desiredrotation of the input shaft 51, which in tum is transmitted to the output shaft 52 into adesired transmitted rotation depending on the chosen gear ratio. The common inputshaft 51 extends aside of the roll 41 to have its input gear wheel synchronouslyconnected to both of the gear boxes 50. Preferably the gear ratio is such to provide asubstantial reduction, e.g. 10/1 -100/ 1, to enable easy displacement of the collet 54 alsoby the use of relatively low input torque, e.g. manually or a relatively small motor. Asused herein, rotation refers to at least a partial rotation, i.e. rotation may thus refer to aportion of one revolution, one or more revolutions with or without any additional portion of a revolution etc..

The output shaft 52 is connected to a lever member 53 by means of outer threads 520 onthe output shaft 52 that are interacting with inner threads of a socket 530 attached at oneend 532 of the lever 53. The lever 53 has its opposite end fixedly attached to the collet54, e.g. by means of a pair bolts 531. Accordingly, rotation of the upper shaft 52 will betransforrned to movement of the socket 530 and thereby also move the lever 53, whichin tum will rotate the collet 54. Since the collet 54 is rotatably mounted within a circularmounting 600 in the frame of the support structure 6, the lever 53 will follow therotating movement of the collet 54. As a consequence, the shaft 520 will slightly pivotduring rotation of the collet 54, which is enabled by having the transmission 50pivotally attached to the support structure 6, e.g. to an extended part 611A of a cantilever 611. Accordingly, the lever member 53 will move forth and back depending 13 on the direction of rotation of the output shaft 52, which in turn is dependent on the direction of rotation of the input shaft 51.

The shaft 410 of the upper roll 41 has each end mounted within said collet 54 by meansof a bearing 55 that enables friction free rotation of the roll 41 in relation to the collet54. The centre C54 of the mounting hole 540 within the collet 54 does not coincide withthe centre C41 of the outer periphery of the collet. Accordingly, the shaft 410 of the rollis eccentrically positioned in relation to the centre C41 of the collet 54. As aconsequence, the position of the roll 41 will be altered when the collet 54 is rotated. Theaforementioned respective location may thus be defined by a distance from the centerC41 to the center C54, e. g. in the radial direction from the center C41. Accordingly, thepressure adjustment arrangement 5 provides for the ability to adjust the nip gap ND andthereby also adjust the pressure excerpted onto the mat of fibrous material by the rolls 41, 42 in the nip.

In the figure it is shown that the driving member 51A of the input shaft 51, is in theform of a wheel that may be operated manually. It is evident for the skilled person thatthis driving member may also be driven by a motor, e. g. an electric motor or hydraulic motor.

Figure 6 shows an exploded view illustrating details of an exemplifying mountingassembly for installation of a roll, such as any one of the front, upper, lower and rearrolls 40, 41, 42, 43 or the like. The exemplifying mounting assembly makes it easy tochange a roll. An advantage of the exemplifying mounting assembly is hence that a roll,such as the upper roll 41, may easily be mounted at or de-mounted from the supportstructure 6. A shaft 411, about which the upper roll 41 is rotatable, is rotatablysupported by the respective bearings 55. The shaft 411 includes a respective bearingsupport 416 at which the shaft 411 is held in place in the support structure 6. At a distalend 415, a first diameter of the shaft 411 may less than a second diameter at a midpointof the shaft 411. Distally of the one of the respective end portions 461 that is closest tothe distal end 415, the shaft 411 may be tapered such that the diameter of the shaft 411 smoothly converges towards the first diameter. When the shaft 411 is extracted in the 14 axial direction of the roll 40, 41, 42, 43, the roll 40, 41, 42, 43 may be demounted fromthe apparatus 100. Furthermore, upon mounting of the roll 40, 41, 42, 43, it may be heldin place, e.g. by a truck or robot grabbing around the roll without obstructing the endsthereof, next the shaft 411 is inserted into the roll 40, 41, 42, 43 to rotatably fasten it in the apparatus 100.

In the shown exemplified embodiment in figure 6 there is shown a preferredembodiment of mounting of the rolls 41, 42 in the nip, by showing an exploded view ofpreferred mounting parts of the roll shaft 411 of the upper roll 41. The shaft 411 has adriving end 415 onto which the driving power from the motor 410 is applied. Furtherthere are two bearing supporting areas 416 on each side that rotatably support the shaft410 by means of bearings 55, within the collets 54. To fixate the roll body 412 on theshaft there are arranged clamping members 57. Locking members 59 are arranged toaxially fixate the shaft 411 in combination with attachment flanges 59. The arrangementfacilitates the possibility of removing a roll 41 by means of suspending the roll body412 in position, removing fixating members and thereafter pulling the shaft 411 out ofthe roll body 412 sideways, such that the roll 41 may then be lifted out of the support structure 6.

Figure 7 shows the lower roll 42 of the apparatus 100 illustrated above. As mentioned,there is thus provided an exemplifying apparatus 100 for dewatering f1brous material 2.The apparatus 100 comprises the upper roll 41 and the lower roll 42 that form the nip Nin which water is pressable out of the fibrous material 2.

In the cross-sectional new of Figure 7, the respective circular collets 54 are referred toas a first circular collet 54A and a second circular collet 54B that are arrangedperipherally of the respective bearing 55.

At the distal end 415 of the shaft 411, which projects from the support structure 6, a motor 420 may be installed for rotational driving of the lower roll 42.

In figure 7 there is shown a cross sectional view of the lower roll 42 in the nip and itsattachment into the support structure 6. There is shown the position 416 (see Fig. 6) ofthe bearings 55 on the shaft 411, which is identical for both rolls 41, 42, as many other parts of the mounting arrangement. However, for the lower roll 42 there is noeccentrically adjustable collet 54 but instead fixed collets 54A, 54 B. Hence, the collets54A, 54B are preferably not rotatable, within the mounting hole of the frame 6.

Figure 8 shows a detail of the lower roll 42 shown in Figure 7. The lower roll 42 ischaracterized by that a cylindric surface of the lower roll 42 is provided grooves 425extending at the periphery of the lower roll 42 and transversally in relation to,preferably perpendicular to, the axial direction of the lower roll 42, thereby formingridges 426 extending in the rotational direction. Each ridge presents a respective surface42A facing a respective radial direction of the lower roll 42, the respective surface 42Abeing a respective portion of the cylindric surface. A width v of the respective surfacealong a longitudinal direction of the lower roll 42 is greater than a distance t in thelongitudinal direction between opposing edges of the respective surfaces 42A of twoconsecutive ridges 426. In one alternative there are a plurality of separatecircumferentially extending grooves 425, that run perpendicularly in relation to the axialdirection of the lower roll 42. In more detail, the grooves 425 may run along and/orparallelly with a circumference of the lower roll 42. In another alternative, there may beone or more circumferentially extending grooves, that run along one or more helical paths.

In one example, a depth d8 of the grooves between said two consecutive ridges 426 istwice the width v of the respective surface 42A, the depth d8 being defined as a lengthfrom a point at a bottom surface 42B of the groove 425 to a point at the respectivesurfaces 42A of one of said two consecutive ridges 426. The distance is taken along aradial direction of the lower roll 42. The point at the bottom surface 42Bof the groove425 is located at a minimum distance from a center of the lower roll 42. Said twoconsecutive ridges are preferably consecutive along the rotational direction of the lowerroll 42. As described above, the lower roll 42 may typically have a ribbed cylindrical surface, wherein the lower roll 42 may be referred to as a ribbed roll 42.

According to various examples, the ridges 426 and/or the grooves 425 have a rectangular cross-sectional shape, a polygonal shape, a triangular shape or the like. In 16 some examples, the cross-sectional shape may be formed by a combination of arectangle and a circular sector having a diameter that is equal to, or almost equal to aside of the rectangle on which the circular sector may be arranged, such as standing.The circular sector may then form a bottom of a groove. The width V may be in a rangefrom 2-8 mm, preferably 4-6 mm, more preferably approximately 5 mm. The distance tmay be in a range from 1/2-4 mm, preferably l-3 mm, more preferably approximately 2mm. The depth d8 may be in a range from 6-l4 mm, preferably 8-12 mm, morepreferably approximately l0 mm. As may be seen from Figure 8, the surface 42A of thelower roll 42 is arranged with a plurality of circumferentially extending grooves 425.The grooves assist in the de-watering process by means of enabling escape of the waterbeing pressed out of the fibrous material in the nip. The water may escape through, or in, the grooves 425 e. g. due to gravity.

In Figures 9, l0, ll and l2 there are shown different views of the front roll adjustmentarrangement 3, basically including the front roll 40 and two parallel support members300, preferably in the form of vertical support plates, that support the roll 40. The roll40 is adjustably arranged between the support plates 300 in order to be able to tensionthe band 35 and to be positioned in a correct position during operation. Figure 9 is aside View illustrating details in the vicinity of the front roll 40. Figure 10 is a cross-sectional view in the plane D-D of Figure 9. Figure l2 is a cross-sectional view in the plane G-G of Figure ll.

The front roll adjustment arrangement 3 may also include a pivot arrangement 3 l ,including pivot shafts 302. The pivot shafts 302 are attached to a base frame of themachine, see e.g. beams 63, 68, and enables the support plates 300 to pivot such that theangle ot between the horizontal and the band 35 up to the nip between the two nip rolls4l, 42 may be adjusted. Preferably this angle ot should be in the range of 3°-23°, morepreferred 50-200, most preferred 5°-l5°, to optimise, or at least improve, the processaccording to a preferred embodiment of the invention. An advantage with having theangle ot of the band 35 adjustable is that the raw material may then be supplied to thenip between the rolls 4l, 42 and always have the lower roll 42 supporting the rawmaterial in connection with contact with the surface of the upper roll 4l. Accordingly, the pressure exerted by the upper roll in a downward direction will then have the surface 17 of the lower roll 41 as the support. This fianction is described based on having the tworolls 41, 42 positioned along a vertical line, implying that it is not required that the band35 is positioned at an angle in relation to the horizontal, but rather at an angle ot inrelation to aligned norrnals through the nip of the two rolls 4l, 42. Accordingly thiseffect may also be achieved by instead having the band 35 horizontal and arranging thealigned norrnal of the rolls along an angle ot that is offset in relation to the vertical. If notthis angle ot is arranged within the nip there is a risk that the pressure exerted by the upper roll when material is entering the nip may cause damages to the band 35.

Further, the diameter DN of the rolls 4l, 42 in the nip, i.e. press rolls, may have aninfluence regarding efficiency and also cost. The smaller diameter DN the larger peakpressure may be achieved with the same amount of linear load. Tests have shown thatthe diameter DN may preferably be in the range of 400-1200 mm, more preferred 600-l000 mm. Preferably the diameter DT of the retum rolls 40, 43 are larger, i.e. DT >DN. The diameter DT of the tuming rolls 40, 43 (rear roll and front roll) may preferablybe in the range of 500 - 2000 mm, more preferred 600-1500 mm The support sides 300 of the arrangement to hold the front roll 40 in a desired positionalso includes adjustment units 3 l3, 3 l4 having one part in contact with the base frameof the machine and another part attached to the support sides 300 and an adjustablemember in between, such that the desired angle ot of the band 35 may easily be adjusted,before a fixation arrangement 303, e. g. screws, are secured, passing through curved passages.

There is also a conveyer tensioning arrangement 3l which makes it possible to positioneach end on the shaft 40l carrying the roll 40 independent of the other end along linearguides 3 l l, 3 l2. Preferably, there are arranged two linear guides 3 l l, 3 l2 extending inthe longitudinal direction of the machine on each inside of the support sides 300. Eachlinear guide 3 l l, 3 l2 comprises in a male part 3 ll that is interf1t with a female part 3 l2,wherein the one part is fixed to the inside of each support side 300 and the other part ismoveable relative the other part 3 l2 and fixedly attached to a roll support 305. Each rollsupport 305 accordingly carries at least one, preferably two, guide members 3 ll ontheir outsides. Centrally in the roll supports 305 there is a through hole arranged with abearing 3 l0, which in tum carries the end of the roll shaft 40 l. 18 Centrally the roll shaft 401 may have a larger diameter arranged for interf1t withattachment members 403, 404, which provide for the possibility of fixating the roll 40adjustably along the central part of the roll shaft 40l and by carrying the roll sides of thebody 402 of roll 40. The roll shaft 401 is positioned adjacent one end of the supportsides 300 that is opposite to the attachment of the support sides 300 to the base frame of the machine.

According to a preferred embodiment of the invention it includes a conveyor tensioningarrangement 34, which preferably is achieved by having each movable roll support 305connected to a tensioning device 33, such as a linear actuator. According to oneembodiment this may be achieved by having each roll support 305 attached to an outermember 330 of a linear actuator 33. The linear actuator has a base 33l that is fixedadjacent the downstream end of the support sides 300 and includes a gear mechanismthat is driven by a motor 306 and which transmits the rotation from the motor to providea linear movement of the moveable member 309 of the linear actuator 33, as is known per se.

Thanks to the tensioning devices, e.g. linear actuators 33, it is possible to tension theband 35 at varying desired levels, independently on each side and thereby also at thesame time to position the shaft 40l of the roll 40 to have the band running along the rollsurface at a position that is desired, i.e. norrnally centred on the roll 40. Accordingly,thanks to this arrangement it is possible to maintain the position of the band withindesired limits in a transversal direction to reliable feed the raw material in to the nipbetween the rolls 4l, 42. As is evident for the skilled person this is achieved by the factthat a slight offset of the roll shaft 40l will produce a counterforce from the pre-tensioning of the band 35 which in tum may produce transversally directed forces onthe band such that it may start be displaced in a transversal direction along the rollsurface. A preferred range of adjustment on each side is at least 30 mm, more preferred50-100 mm and a preferred range of tension applied is at least l5 kN, more preferred 20 -40 kN.

By adjusting the position of the roll such undesired transversal displacement may bestopped and by correctly position of the two linear actuators 33 the band will both have a desired pre-tensioning and a desired position on the surface on the roll 40. The 19 mounting part 308C of the linear actuator 33, which preferably includes a shaft 310,includes a force sensing device, e. g. a pressure and/or tension sensing member. Thanksto having the linear actuator 33 attached to the support sides 300 in this manner theexact force applied to each side of the roll 40 may be both measured and controlled,which is a major advantage in order to reliably control a desired tension of the band 35 and also to position the band 35 correctly in relation to the surface of the roll.

There are also shown a plurality of cleaning units 315, 316, 317, arranged to clean theband 35 and the front roll 40, respectively. Preferably each cleaning unit includes ashaber, and more preferred combined with water flow or spray to enhance the cleaningeffect. This combination is especially preferred for a first cleaning unit 315 that cleansthe inside surface of the band 35. In the shown embodiment there is a second shaber 316that cleans the surface of the front roll 40 and a third shaber 317 that cleans the outsidesurface of the band 35. The third shaber 317 is preferably supported by a separatesupport device 301. (see Figs. 1 and 2).

In Figure 13 there is shown the raw material supply system 1 in more detail, in aperspective view from above. It is shown a supply chute 10, e.g. a chip chute, having asubstantially rectangular cross section enclo sing an upper space 10A and a lower space10B (shown in Figure 2), wherein the cross section of the lower space 10B is larger thanthe upper space 10A, by both having the same transversal width L10C and the lowerspace 10B having a larger longitudinal width L10B (e. g. 1200- 2000 mm), than thelongitudinal width L10A (e.g. 1000-1500 mm) of the upper space 10A. Within thelower space 10B, at the bottom level of the supply chute 10 there is arranged a rawmaterial feed system 11, which includes a plurality of screw feeders 11 A, 11B, 11C,preferably three. The plurality of screw feeders 11 A, 11B, 11C are arranged in parallelhaving a driveshaft 110 arranged in the length direction of the machine. The driveshafts110 are driven by a motor 118 via a gear box attached to a first side 10C of the chuteand have their far ends positioned at a second side of the chute, at an outlet opening 117 at the outlet end of the lower space 10B.

Helical plates 111 are attached to the shaft 110 preferably having a radius, R111 that isin the range of 1,5-3 times the radius R210 of the shaft 210. The pitch of the helicalblade 211 is such that it is larger than the shaft diameter, preferably larger than 2 x R210. The length L110, (substantially the same as the longitudinal width L10B) of eachscrew 11A, 11B, 11C is such that it preferably includes between 5 and 15 tums exposedwithin the space of the chute 10. The total diameter D211, 2 x R211 is preferably withinthe range 7 x D211 > L10B > 2 x D211. The positions of the helical blades 111 arepreferably phase shifted, i.e. an edge facing a neighbouring screw feeder 11 A, 11B,11C will be positioned in between two opposing edges of neighbouring screw feeder,which implies that they may be positioned very close to each other (even slightlyoverlapping) when they rotate (all rotate in the same direction) and maintaining a gapbetween the edges, i.e. without risk of j amming raw material between them. Thetransversal width L10C of the chute 10 is preferably within the range 0,8 (n x D211) to 1,2 (n x D211), where n is the number of screw feeders.

The screw feeders 211 are positioned above a supply surface 114 at the bottom of thechute 10. the screw feeders 11A, 11 B, 11C will push the raw material along this supplysurface 114 and push the raw material, out through the opening 120 from the lowerspace 10B. Preferably the output edge 114A of the supply surface 114 is positionedalong the same vertical line as the outlet opening 117. The output edge 114A ispositioned slightly above the band 35 and preferably positioned further in thelongitudinal direction than vertical centreline through the centre of the front roll 40.Thanks to this arrangement the screw feeders 11A, 11B, 11C may feed raw material on to the band 35 and at a position that safeguards forward transport of the raw material.

The supply chute 10 is supported by a fixed lower support plate 118. On top of thatsupport plate 118 there is arranged an adjustable support plate 119, which is slidablyarranged in the longitudinal direction in relation to the fixed support plate 118. Thanksto this arrangement the front edge 114 A of the outlet from the supply chute 10 may beadjusted in the length direction. This feature may be a significant advantage inapplications where the position of the front roll 40 may be adjusted, e.g. by pivoting thesupport structure 30 to have the angle u of the band 35 at varying angles. Accordingly,if a lower position of the front roll 40 is chosen the position of the outlet 114 A may beadjusted and moved in direction to the nip to have the lower edge of the outlet 114 Awith a desired gap in relation to the band 35. Further, it is foreseen that this function may also be beneficial in connection with feeding of raw material to another kind of 21 infeed device than a band 35, e. g. an infeed device substantially merely including the rolls 41, 42 ofthe nip N.

The supply surface/bottom portion 114 of the supply chute may preferably be in theform of a tube half (not shown) for each screw 110, 111. The reason for this is that thepreferred embodiment of screw feeders ll need no support at their frontends, i. e. noneed of barring. However, in many applications for use of the invention there is a needof keeping the screw feeders 110, lll in desired positions lengthwise, i.e. a part not tointerfere with each other. Accordingly, such tube halves have an inner diameter that isadapted to the diameter of the helical blades 11 and are fixedly attached to each other not to leave gaps in between the parallel tube halves.

Furthermore, preferably the speed of each feeder tube l 1A, llB, llC may beindependently controlled, to establish desired homogeneity of the raw material that isdelivered on to the band 35. The reason for this is that the raw material supplied via thechute 10 may have a tendency to provide larger supply of raw material onto one sidethan the other, if the screw feeders are driven with the same speed. Accordingly, thismay be adjusted by adjusting the speed of the screw feeders l 1A, llB, llC to provide for a more homogeneous supply of raw material on to the band 35.

Further as noted there is preferably arranged retaining plates 201 on each side of theopening 117 of the supply chute, having the main purpose to retain the raw material onthe band 35. In a preferred embodiment these retaining plates 201 are made in atransparent material such that the raw material supplied to the band 35 may easily be observed visually.

Moreover, it is shown that on top of the moveable or adjustable support plate 119 at theback end of the supply chute 10 there is a pivotal support member 115 having a supportpart 1l5A attached to the supply chute bottom 114 and a pivot shaft 115 B that isrotatable fixated within a support foot 115 C. This arrangement will enable the outlet1l4A to be adjustably positioned by pivoting into a desired angle ß in relation to theinfeed device (as indicated in Figure 2 by a dotted altemate position of the bottom114“), e. g. a band 35. Further, it is foreseen that this pivotal function may also be benef1cial in connection with feeding of raw material to another kind of infeed device 22 than a band 35, e. g. an infeed device substantially merely including the rolls 41, 42 of the nip N, such as a dewatering nip.

At the other side of the moveable support plate 119 there is arranged a measuringsupport device 116, which is made possible thanks to having at least the bottom of thesupply chute 10 movable in the vertical, e. g. by means of a pivoting design asmentioned above. By means of this measuring support device 116 the amount/ load ofraw material being supplied can be measured in real time. This measurement mayprovide relatively exact figures regarding the amount of raw material being supplied,since the moisture content of the raw material is known and thereby also the density andwhich in tum provides the possibility to calculate the exact amount being supplied.Preferably tension gauges or load cells are being used within this measuring support device 1 16.

The front end of the lower chute space 10B is preferably totally open, since in apreferred embodiment there is no need of any support structure for the screw feeders atthe outlet end 114 A. However, it may be preferred to arrange an upper limit plate (notshown), below the upper wall of the lower space 10B to adapt the height of the space 10B to the size of the screw feeders.

Figure 14 through Figure 20 illustrate various parts and features of an exemplifyingsupport structure 6. Figure 17 is a combined side view and cross-sectional view along aplane C-C in Figure 16. Figure 19 is a cross-sectional view along a plane A-A in Figure 18 and Figure 20 is a partial cross-sectional view along planes B-B in Figure 18.

A support structure 6 for supporting rolls 42, 43 for dewatering wood material 2delivered at the band 35 to a nip N formed between the rolls 42, 43 is provided. Thesupport structure 6 is arranged to allow insertion and removal of the transfer belt bydisplacement of the band 35 along an axial direction of the rolls 42, 43 when installed in the support structure 6, without need to demount any of the rolls 42, 43.

The support structure 6 comprises a first side wall 60A that is perpendicular to the axial direction of the rolls 42, 43 when these are installed in the support structure 6.

A first cantilever 611 and a second cantilever 610 extend from the first side wall 60A.

Preferably the first cantilever 611 forms a separate part, which is supported by an upper 23 part 613 of the transversal wall 61. (see Figure 19) More preferably, the first cantilever611 is in the form of a plate having extension 611A on both sides for attachment of oneor more parts 50 of the pressure adjustment arrangement 5. As used herein, the terrn“cantilever” is used to describe e.g. a beam or similar element that projects e. g. from a wall, another beam or the like.

With reference to Figure 19, the transversal wall 61 may comprise a rigid back end part615 that forms an integral base portion for the second cantilever 610, e.g. from whichthe second cantilever 610 projects. Hence, the second cantilever 610 preferably forms apart of the transversal wall 61 that is positioned adjacent the centre of the supportstructure 6 seen in the machine direction. The second cantilever 610 forms a part that ispositioned above a lower wall base 614, wherein both the second cantilever 610 and thelower wall base 614 may preferably be connected by the rigid back end part 615, e. g.such that the second cantilever 610 and the lower wall base 614 becomes integratedwith each other, i.e. forrning an integral part. Between the second cantilever 610 and thelower wall base 614 there is a passage 616, providing space in the transversal wall 61for passage of the band 35. The lower wall base 614 is connected to the third wallportion 66, e.g. via a backing member 64. Accordingly, the third wall portion 66 isconnected to the first side wall 60A via a lower, transversal wall base 614 and preferably one or more beams 63, 68, to form a base frame or the like.

The support structure 6 comprises a second side wall 60B located opposite relatively therolls 42, 43 to the first side wall 60A and parallelly to the first side wall 60A. Thesecond side wall 60B comprises a first wall portion 67, a second wall portion 65 and athird wall portion 66. A through hole 604, may be provided in the first wall portion 67, for the common shaft 51 shown in Figure 5.

The first wall portion 67 is connected to the first side wall 60A via the first cantilever611. Further, the first wall portion 67 may be more stably connected by means of beingconnected by a third cantilever device 601, 605. Also, the third cantilever device 601, 605 may be used to support another unit of the machine, e.g. the levelling out device 2.

The second wall portion 65 is connected to the first side wall 60A via the second cantilever 610. 24 The third wall portion 66 is connected to the first side wall 60A, via beams 63, 68, toform a rigid base frame. The base frame may have feet 660 for fixed attachment to a a basic support frame 8.

A first gap G4 (see Fig. 14) is formed between the first wall portion 67 and the secondwall portion 65. A second gap G6 (see Fig. 14) is formed between the second wallportion 65 and the third wall portion 66.

The first wall portion 67 and the second wall portion 65 are provided with respectiveattachment interface halves 673, 653 on one side each of the first gap G4, forrning ajoint attachment interface 673/653 for attachment of a holding arrangement 69. Theholding arrangement 69 bridges the first gap G4, such that it keeps the first wall portion67 and the second wall portion 65 in positions during use, i. e. transfers forces (mainlytension) between the first wall portion 67 and the second wall portion 65. Preferably,the holding arrangement 69 keeps the first and second wall portions 67, 65 in fixedpositions, e.g. relatively each other. The holding arrangement 69 prevents the first gapG4 from being extended, such as enlarged, widening or the like. Preferably, the holdingarrangement 69 comprises two holding members 69A, 69BB (see Figure 20) which areclamped onto a respective side of the attachment interface at a respective side of aroundthe gap G4, e.g. by bolts in bolt holes 654, 674, 694 on each side of the gap G4. Thismeans that the holding members 69A, 69B comprises a first holding member 69A and asecond holding member 69B. More preferably, the face 693 of each holding memberhalf 69A, 69B has recesses/protrusions forrning edges 694, which interact withcorresponding edges 655 of the attachment interfaces 673, 653, respectively, such thatsaid edges 655, 695 assist in keeping the two wall portions 67, 65 in positions. In theexemplary embodiment these edges 655, 695 are in the form of longitudinal planarsurfaces, being planar in two orthogonal directions, extending parallelly with theextension of gap G4. Moreover, the middle bolt 696 of the holding arrangement 69 runs,preferably freely, within the first gap G4, to interconnect the holding members 69A,69B, aka a first and a second holding member. In this manner, the middle bolt 696, orbolt 969 for short, facilitates mounting and demounting of the holding arrangement 69,since the second holding member 69B may thanks to the bolt 696 be guided along thefirst gap G4, e. g. to where the holding arrangement 69 may be removed from the support structure 6. An advantage is that the second holding member 69B is not easily dropped down into the support structure 6, where it would be difficult to reach the second holding member 69B.

However, it is evident for the skilled person that the surfaces forming the edges may becurved in the longitudinal extension and fulfil the same function and that the shownmale/female interfit may be reversed. Preferably, the surfaces forrning the edges 655,694 in the lateral direction, however, are planar and extend in parallel with the boltholes 654, 674, 694. Preferably there are two parallel surfaces 695 facing towards eachother on the holding member 69 and two parallel surfaces 655 facing away from eachother on the interface 653. The opposite surfaces 657, 677, 697 preferably are tapered,e. g. l0-20°, to enable high precision fit. In the exemplary embodiment the edges 655,675 and the opposite surfaces 657, 677 in the wall portions 67, 65 are formed by twoparallel longitudinal grooves 678, 658 and the edges 655, 694 and opposite surfaces 697of the holding members 69 are in the form of protruding ridges along the longitudinal direction of the machine.

The second wall portion 65 and the third wall portion 66 are provided with respectivesupport interfaces 659, 669 for interfit of the backing member 64. The backing member69 bridges the second gap G6, such that it keeps the second wall portion 65 and thethird wall portion 66 in fixed positions during use, i. e. transfers forces (mainlypressure) between the second wall portion 65 and the third wall portion 66. Preferablythe backing member 64 comprises a pressure withstanding body 640 solid (see Figure20) and an attachment plate 64l, which body 640 is introduced into the recess formedby the support interfaces 659, 669 to thereby eliminate the influence of the gap G6.Preferably, the backing member 64 is attached by means of bolts 643 by adapted boltho les 644 in the attachment plate 64l and corresponding threaded ho les in the two wallportions 67, 65, on each side of the gap G6. A handle 642 may be provided for easy removal.

According to another aspect, it is herein disclo sed a method for removing or inserting aband 35 delivering a fibrous material to a nip N formed between at least two rolls 4l, 42supported by a support structure 6 for supporting said at least two rolls 4l, 42. Anapparatus 100 for dewatering the fibrous material 2 comprises the support structure 6.

The method comprises: 26 0 demounting a holding arrangement 69 arranged to bridge a first gap G4, formedbetween a first wall portion 67 and a second wall portion 65, which arecomprised in a second side wall 60B of the support structure 6, and to keep thefirst and second wall portions 67, 65 in positions during use, 0 demounting a backing member 64 arranged to bridge a second gap G6 formedbetween the second wall portion 65 and a third wall portion 66, comprised in thesecond side wall 60B of the support structure 6, and to keep the second and thirdwall portions 65, 66 in fixed positions during use, wherein the method furthercomprises at least one of: 0 removing the band 35 from the nip N between the rolls 42, 43 by extracting theband 35 in an axial direction of the rolls 41, 42, and 0 inserting the band 35 between the rolls 4l, 42 by inserting the band 35 in theaxial direction of the rolls 41, 42, and wherein the method further comprises: 0 mounting the holding arrangement 69, whereby the holding arrangement 69bridges the first gap G4 when mounted in the support structure 6, and 0 mounting the backing member 64, whereby the backing member bridges the second gap G6 when mounted in the support structure 6.

According to some embodiments, the demounting of the holding arrangement 69comprises untightening a screw 696, e.g. partially releasing the screw 696, to allow theholding arrangement 69 to be slid along a longitudinal extension, preferably horizontalextension, of the second side wall 60B for removal thereof from the support structure 6, whereby the first gap G4 becomes unobstructed.

According to some embodiments, the demounting of the backing member 64 comprisesreleasing backing screws 643, 644 to allow the backing member 64 to be extracted in anormal direction to the second side wall 60B for removal thereof from the support structure 6, whereby the second gap G6 becomes unobstructed.

According to some embodiments, the removal of the band 35 comprises removing theband 35 from a front roll 40 and a rear roll 43, which are supported by the support structure 6, wherein at least one of the front and rear roll 40, 43 is movably arranged in 27 relation to the support structure enabling releasing tension of the band 35.

According to some enibodinients, the insertion of the band 35 coniprises inserting theband 35 into the apparatus 100 and onto the front roll 40 and the rear roll 43, anddisplacing at least one of the front and rear rolls 40, 43 to reapply tension at the band35.

Claims (4)

1. Supply chute (10) for a deWatering press, comprising a container body (10)having an upper part (10A) With an inlet (101) and a lower part (10B) With anoutlet (117), a bottom portion (114) and a supply arrangement (11) arranged tofeed raW material along the bottom portion (1 14) out through the outlet (1 17),characterised in that said feeding arrangement comprises a plurality of parallellyarranged screw feeders (11A, 11B, 11C) along said bottom portion (114), andthat said bottom portion (114) has a length (L 10b) in the feeding direction thatis larger than the corresponding length of the upper portion (10b) of supply chute. Supply chute (10) according to claim 1, characterised in that said bottom portion(114) is arranged With at least one adjustment device (115, 116, 119) enablingadjustment of the position of the outlet (114A) of said bottom portion (114). Supply chute (10) according to claim 2, characterised in that said bottom portion(114) is supported by support members (115, 116) arranged to provide for anadjustable angle (ß) of said bottom portion (114) in relation to a horizontal plane(HP), Wherein preferably said support members (115, 116) comprise a rearsupport member (115) that is pivotally attached to said bottom portion (1 14) andthat a front support member (116) is arranged to provide for adjustable height ofsaid outlet (1 17). Supply chute (10) according to claim 2, characterised in that said bottom portion(114) is adjustably, slidably supported by being mounted on a movable supportplate (1 19). Supply chute (10) according to any of claims 1-5, characterised in a said frontsupport member (116) of said bottom portion (114) is provided With a Weight measurement means (1 19). 10. 11. 29 Supply chute (10) according to any preceding claim, characterised in that eachscrew feeder (11A, 11B, 11C) comprises a shaft (110) driven by at least onemotor (118) at one end opposite to the other end that is positioned adjacent saidoutlet (117) and having a helical blade (111) arranged around said shaft (110),wherein preferably two neighbouring screw feeders (11A, 11B, 11C) arearranged such that a helical plate portion that protrudes in the direction of theneighbouring screw feeder is positioned in-between two opposing helical blade portions (111) of the neighbouring screw feeder. Supply chute (10) according to any preceding claim, characterised in that saidbottom portion (114) includes screw position members arranged to stabilise theposition of each screw feeder (11A, 11B, 11C9 wherein preferably said screwpositioning members are in the form of longitudinally divided pipe elements having an inner diameter adapted to the diameter of the helical blades (111). Supply chute (10) according to claim 6, characterised in that said shafts (110) are merely supported by bearings adj acent the driven end. Supply chute (10) according to any preceding claim, characterised in that eachscrew feeder is arranged with its own motor (1 18), wherein preferably the motors (118) may be independently controlled, also regarding speed. Method for feeding of raw material out of a supply chute (10) according to anyof claims 1-8, characterized by providing said bottom portion (114) with at leastone adjustment device (115, 116, 119) enabling adjustment of the position of theoutlet (114A) of said bottom portion (114). Method according to claim 9, characterized by enabling said adjustment byadjusting angle (ß) of said bottom portion (114) in relation to horizontal plane (HP) and adjusting said angle (ß) in relation to the position of an infeed device. 1

2. Method according to clain1 9 or 10, characterized by enabling said adjustnient byslidably adjusting the position of the outlet (1 14A) of said bottom portion (114) in relation to an infeed device. 51

3. Method according to clain1 9, characterized by controlling supply of rawn1ateria1 by means of adjusting rotational speed of at least one of said screwfeeders (1 1A, 11B, 11C).10 1

4. Method according to clain1 14, characterized by independently adjusting rotational speed of at least two of said screw feeders (l 1A, llB, llC).