FI57983B - FOERFARANDE FOER ATT RAFFINERA OCH DEFIBRERA FIBERMASSA SAMT EN DEFIBRATOR ATT ANVAENDAS HAERVID - Google Patents

Description

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Patent · och registerstyrelsan 'AnaMon utkgd oeh utukriftm puMttarad 31.07.80 (32) (33) (31) * rri «* r« uoii »tu ·. »« | Std pnontac (71) Bolton-Emerson, Inc., Lawrence, Essex, Massachusetts, USA (72) Donald Worth Danforth, Andover, Essex, Mass., USA (7 ^) Oy Borenius & Co Ab (5 ^) Method for grinding and refining fibrous pulp and the fiber used in this process - Förfarande för att raffinera och defibrera fibermas samt en Defibrator att anvandas härvid

The invention relates to a process for grinding pulp and refining fibers and to a fiberizer used in this connection.

In papermaking, a fiberizer is a device used to convert a cellulosic material into a fiberized aqueous slurry that can be pumped for further processing. Different types of fibers have been developed, originating from a simple open rotor rotating at its upper end in an open cylindrical container. By using a fixed wing element with which the rotor blades can interact, additional fibrous capacity can be provided and thus the overall efficiency can be improved. When using an open rotor, there is a limit to the power (which ultimately depends on the diameter of the rotor, the number and height of the rotor blades, and the speed that can be used without excessive vortex. By using a fixed blade element mainly surrounding the rotor, power can be increased without unnecessary rotation. that this additional power is converted into useful power.

When delivered with a fixed and rotor gap between the stator, i.e. the clearance, there is a limit to the amount of defibering (and the amount of fiber treatment 2,57983) that can be accomplished in this way. By allowing the rotor to move axially with respect to the stator, this clearance can be adjusted and this clearance is in fact reduced to virtually zero to achieve efficient separation of the fibers. In addition to the mere defibering, it is also possible to actually refine · (i.e., cut and fibrillate the fibers) by applying sufficient thrust between the surfaces of the rotor and the stator. By forcing the fibers to pass between the rotor and the stator under considerable thrust, significant refining can be achieved, not only defibering otherwise difficult-to-defibrate materials, but in fact contributing to the refining of the fibers themselves so that the slurry is easily pumped later. handling procedures.

Such treatment has been found necessary when handling non-conventional materials such as leather, certain coarse wastes, hemp, flax, rags and other such materials. Due to the characteristic tough and messy nature of such materials, their comminution into a pumpable form has conventionally been performed in cholera blades, which are efficient but incur a lot of labor and maintenance costs. When treating such materials in conventional defiberers, these materials are resistant to comminution and are furthermore impossible to defiber because the effect between the impeller rotor and the stator (when using a fixed clearance) is insufficient to break the mass into a suitably fibrous space. On the other hand, refiners can refine such material only if it has been suitably pre-treated and thus reduced in size to suit the refiners.

The object of the invention is to combine these two normally independent treatments to take place in a single unit so that the refining can in fact be carried out in a fiberizer.

According to the invention there is provided a method of defibering and raffinizing an unusual material such as hemp, flax, rags and leather by means of a pulp tank having a winged stator and a rotor having a frustoconical abrasive surface and means for causing this rotor to move axially towards said stator. is loaded into 3,57983 tanks, the rotor is rotated using zero clearance and subjected to increased compression to provide a grinding effect and to fibrillate and refine these fibers while still in this tank, after which said rotor is withdrawn from the stator and said fibers are retracted from the stator.

According to the invention there is also provided a vortex flow generating fiber comprising a rotor and a stator which form a frustoconical abrasive interface therebetween, clearance adjusting means for adjusting the clearance of this interface to approximately zero, drive means for rotating this rotor at said zero force is charged to this fiberizer to grind this material into a flowable space, and recirculation devices in the fiberizer to recycle the material discharged from said interface to the fiberizer until the fibers of this material are homogeneous and refined to the desired extent.

The object of the invention can be realized by constructing a rotor / stator combination of the fiberizer such that the rotor can be adjusted in the axial direction to generate the necessary thrust in the same way as in a conical refiner. Sufficient power must be used to develop the required force. The non-conventional pulp is subjected to a grinding effect which grinds the pulp so that it can flow between said intermediate surface for further defibering and refining. With this method, the fibers can be forcibly separated from one another and, in fact, they can also be physically modified in such a way that a pretreatment of the fibers is obtained.

Prior art defiberizers have not been able to handle the unconventional materials defined above, as these would never be sufficiently fibrous to be pumped out of the tank. These materials are typically so tough, messy, and intertwined that they form a mass that cannot be broken in any way other than by applying a considerable thrust like scissors between the edges of the rotor and stator. Such a mass cannot be torn apart by the hydraulic cutting force of a conventional fiberizer + 57983, nor can this entwined mass be cut with two loose dull scissor blades. The pulp requires both grinding and cutting to allow further processing.

In order to understand how this invention represents an improvement over the prior art, it is necessary to know the purpose of the phrases used and sometimes even misused in some patents.

The following patents use the words Mhankaus "," fiberization "and" refining '·. It should be borne in mind, however, that the fiberizers described in these patents may be capable of rubbing, defibering, or separating the fiber bundles into separate fibers. However, in the case where the clearance remains constant and the power used is constant, refining, i.e. development, of the fibers will not occur, although the patent holder uses the term "refining".

U8 Patent 2,596,586 (Morden), issued May 13, 1932, discloses a fiberizer having a disc-type rotor and an annular stator with abrasion surfaces which are claimed to produce a refining effect. However, with age, the patent does not mention a means to increase the efficiency while reducing the clearance, which measures are essential to achieve refining.

Similarly, U.S. Patent 2,685,826 (Black), issued August 10, 1954, describes the grinding and disintegration of fibers by manually reducing the clearance between the rods, a measure of no increase in power necessary to provide the thrust required to refine the fibers, and no mention of the zero clearance.

According to U.S. Patent 3,428,261 (Molton), February 18, 1969, a defibering rotor at the bottom of a container is provided, which is provided with actuators for adjusting the clearance of the abrasive surfaces. Thus, the abrasive power of the fiber web can potentially be changed automatically, but the patent makes no mention of zero clearance as of devices for generating a force large enough to actually make the fibers refined and fibrillated.

It is likely that when filling rags, hemp, flax, leather, some waste or other similar materials into any of the defiberers of the aforementioned patents or any other defibering agent, water would be squeezed out of this material to form a mat and clog the interface. When attempting to empty the defibrator, this material would clog the pump and drain valve. Batches of material should be removed slightly with the help of grip hooks.

According to the applicant, no prior art defiberer is capable of handling such materials that have never been defibered before and are still affected by the natural forces that hold the fibers together so tightly that a conventional defiberer cannot survive them.

None of the patents describes the high thrust, zero clearance, and actual grinding power of this invention required to enable further processing of the material.

According to the invention, the vane rotor and the vane stator are located on the bottom or side of the fiberizer tank. The rotor is equipped with manual or machine-operated devices for adjusting the clearance of the abrasive surfaces in the axial direction, as in the above-mentioned patents. Thus, this device according to the invention is capable of defibering, grinding and refining.

In addition, the device according to the invention has means for setting the blades at zero clearances and means for increasing the operating power so that it is able to drive the winged rotor so as to actually apply a grinding effect to the material, while fibrillating or refining the fibrous fibers to the desired degree of refining. in addition, there are sensors that detect predetermined degrees of grinding or other factors so that the control power of the rotor is automatically applied when the rotor is moved towards zero clearance and the rotor is pulled back when the desired degree of refining is reached.

The invention is explained in more detail below by way of example on the basis of the accompanying drawings.

Figure 1 shows a side view of a typical side or bottom hand-operated vortex type fiberizer fitted with a device according to the invention for the defibering step of the process.

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Fig. 2 shows, in a manner similar to Fig. 1, an apparatus according to the invention adapted for the grinding and refining stage with zero clearances and using much increased power consumption and thrust.

Fig. 3 shows a view similar to Fig. 1 of an apparatus according to the invention adapted for a pulp removal step which takes place using an increased clearance.

Figure 4 is a side view of a side view of a fiber pulp with a winged rotor and a triangular strip stator, i.e. a pressing member around it.

Figure 5 shows a double strip compression system as shown in Figure 4.

Figure 6 is a schematic side view of a typical side or bottom operated winged and grooved rotor and stator. This figure shows the area of increasing the clearance of the abrasion surface from zero to the normal size.

Figure 6A shows, on an enlarged scale, a side view of the winged and grooved stator.

Figure 6B shows, on an enlarged scale, a side view of a winged and grooved rotor segment.

Figure 7 is a graph showing the application of increased power and the resulting pushing load necessary to refine the fibers in the tank.

Fig. 8 is a graph showing the typical amount of defibering of conventional prior art defiberers and the effect of the increased thrust described herein on this amount.

The drawings show a typical vortex flow fiberizer 30, which is described in detail in U.S. Patent 3,428,261 to Moulton. This fiber is commercially available and is so well known in the art that it needs no detailed explanation. In general, however, this fiberizer 30 has a pulp tank 31 having a vertical side wall 32 and a bottom wall 33, an upper edge 34 7 57983, and abrasives 35 having a winged grooved stator 36 and a winged and grooved rotor 37. Each has a frustoconical abrasive surface 38, resp. 39, which tend to pump the mass outwards from the center of the tank. The rotor 37 has suitable recirculation vanes 41 which cooperate with the coil 42 to generate a helical flow of the pulp charge 44 to be fiberized and comminuted. The abrasives 35 tend to draw material inwardly along the container shaft 45 and then pump it outward either circumferentially along the side of the container and back to the center, or distribute the material outwardly into the collection chamber 46 via line 47 and control valve 50 and further back into the container.

In the fiberizer shown, the abrasive device 35 is fitted in the opening 48 of the bottom wall 33, but it may just as well be mounted in the opening of the side wall 32, as shown in Figures 4, 5 and 6.

The device has clearance adjusting devices 51, which may include filler plates for varying the position of the stator 36 and a manual threaded thrust mechanism for moving the frustoconical rotor or impeller 37 axially toward and away from the frustoconical stator to increase or decrease the clearance. However, the control device 51 suitably has a pneumatic drive device 52 to which compressed air is supplied on both sides of the diaphragm from the air tubes 48 and 49 to cause the rotor to automatically advance and retract as this rotor rotates. Compressed air is supplied through suitable connections from a factory compressed air source to maintain the rotor in the desired axial position and a certain clearance from the stator or to advance or retract the rotor by an automatic cycle control device 53 having conductors 54 and a grinding sensor 55, e.g. manufactured by Bolton-} 2merson, Inc., Lawrence, Massachusetts, or some other sensing device that operates based on the properties of the pulp in the container 31. The electrical circuit 56 has an ammeter 57 for observations through the eyes of the machine operator, and a limit switch 58 which, when the rotor is fully retracted, opens the outlet or discharge valve 59 and empties the container 31 of fully fibrous and refined contents.

The small diameter end 61 of the abrasion surfaces 38 and 39 is closer to the center of the fiberizer than their large diameter end 62, and the stator abrasion surface 38 is suitably impermeable so that it can act as a pump housing. The grooves in the abrasion surfaces may have dams to guide the mass 8 5 798 λ across the intermediate surfaces 63. ^

The pusher device 64 according to the invention comprises a drive motor 65 which in a prior art fiberizer is capable of consuming about 92 kW when the conventional fixed clearance of the abrasive surfaces is about 0.6 mm, which is sufficient e.g. to defiber the waste paper charge in an appropriate manner. As shown in Fig. 7, the so-called an abrasive fiber of the indicated power in the case that there is only water in the tank 31. Once the material to be defibered is added to the water in the tank 31, the power consumption increases to the indicated level, namely about 92 kV /, and remains at this level until the material is defibered, comminuted and ready for removal to the next treatment, usually refining.

Once the batch 43 of non-conventional material has been defibered and comminuted for removal or suitably in conjunction with this defibering, the drive 52 automatically causes the rotor 37 to advance so that the clearance becomes zero (Figure 2) like a conical refiner to develop the desired thrust. A separate motor 66 can be used to supplement the motor 65 to approach the rotor at zero clearance, which requires power of about 130 to 146 kW as shown, to grind unconventional material and to refine and fibrillate the fibers. The material that gets between the rotor and stator blades thus becomes fluid as a result of grinding, and at the same time a considerable amount of thrust is applied to it to cut, defiber and refine it. The amount of thrust is adjustable based on the type of material and the desired treatment. The phrase "grinding" includes cutting, breaking, cutting, shearing, abrasion, etc., as compared with abrasion or weakening and wear of slow grinding due to friction.

"Grinding efficiency · means the rapid reduction of pulp or compositions into discrete elements under high thrust until the pulp is flowing so that further pulping and refining can take place, whereby grinding, defibering and refining take place simultaneously due to the heterogeneous nature of batch processing.

As can be seen from the following examples, when using an unconventional material which is quite resistant to comminution, the apparatus and method of the present invention only provide a suitably shaped stator for handling the material, a rotor with sufficient thrust and proper clearance for grinding and defibering. in that regard, as well as recirculation to allow homogenization so that the entire mass of material can be rapidly and efficiently fiberized and at least partially refined.

To illustrate this, it should be noted that using cooked hemp and a normal clearance of about 0.6 mm between the rotor and the stator, after 30 minutes of treatment, the pulp was still in a completely unacceptable state and the pulp could not be pumped. However, by developing such a high thrust that the power consumption was 125 kW (compared to the normal value of 92 kW), the mass after 30 minutes of treatment was completely fibrous and quite suitable for subsequent treatment. Further processing in the fiberizer thus provides significant comminution of the fibers, which reduces subsequent refining needs. According to another example, cooked cotton pads (mail bags) were used which are very resistant to standard fiber treatment but which can still be treated as described, giving a more acceptable pulp in 30 minutes to increase the pushing load to 146 kW and longer refined pulp longer.

In conclusion, this clearly different fiber treatment method allows significantly more power to be used in a much more efficient way than is possible in a conventional fiberizer, so that materials that have hitherto been considered completely impossible to be treated in the fiberizers can be treated. This solution apparently offers considerable advantages in that it is possible to cope without percussion devices, which, despite the high costs normally associated with them, have hitherto been the only means of handling such materials.

The stator structure according to the invention differs from conventional abrasive fibers manufactured today, which usually have only one strip. If the rotor is advanced in accordance with the invention to generate thrust, a single strip or asymmetrical strip system applies significant deflection forces to the rotor shaft 69. Using two opposed strips 71 and 72, or three evenly spaced strips 73, 74 and 75, as shown in Figures 4 and 9. , the deflection forces are balanced and a considerably large thrust can be used without deflection of the shaft.

The purpose of the ammeter 57 is to indicate the amount of thrust generated. Due to the higher wear that occurs at zero clearance and the thrust is 50% higher than the normal 92 kW power, namely 125 ... 146 kW, the abrasive vanes sometimes have to be replaced, so they are conveniently mounted on the segment plates to allow easy removal and replacement.

Instead of using a single motor of about 92 kW 65 and an auxiliary motor 66, a single motor 65 capable of generating power of about 150 kW or more can be used.

It should be noted that the frustoconical interface formed by the stator surface 38 and the rotor surface 39 is relatively short to form a relatively narrow refining zone. For this reason, a tough messy and difficult-to-refine material tends to pass through this narrow refining zone before this material predisposes to clogging in this zone. * In use, rotor 32 is made to advance to zero clearance with the rotor and stator blades in contact. Although it could be assumed that the rotating part would cut into the non-rotating part or generate excessive heat, it has been found that. this does not happen. Instead, water and fibers act as lubricants, and their mixture absorbs any heat. Although the entire equipment can deform, especially if the rotor is made to pass past the zero clearance under very high load and thrust, the only risk of damage is the possible excessive wear of the blades, which is not particularly dangerous. Despite such wear, which would normally be considered disadvantageous by those skilled in the art, difficult-to-refine material can be fibrillated as desired, which is the object of the invention. The wings can be easily replaced if necessary.

Claims (10)

A method of defibrating and refining fibers in unusual materials, such as hemp, lime, lump and leather, wherein such material is filled into a pulp container (51) and a rotor (37) having a grinding surface (39) in the form of a truncated cone, caused to advance axially against a blade stator (36) to reduce the gap, felt not to cause the rotor (37) to rotate with a gap of zero size, and apply an increased support force to the gap to exerting a grinding action to fibrillate and refine said fibers while still in the container (31), and then cause the rotor (37) to retract from the stator (36) and tear the refined fibers from the container (31). 14 5 7 9 8 3 A method according to claim 1 for treating unusual pulp in a swirl circulation flow-based defibrillator (30) with a blade-and-grooved stator (36), and a rotor (37) having a positive gap between the surfaces, the rotor being driven with a pre-cut determined power and the mass is recirculated by the pumping action at said surfaces, and the defibrillator is filled with unusual mass such as Iin, hemp, lump, leather or the like, felt to cause the rotor (37) to detach until the gap is zero, increasing said power having at least 50% to achieve a sufficient impact force and exerting a grinding action to refine and develop the fibers in such unusual mass for a predetermined time, automatically tests said fibers to have been refined to a predetermined time set standard, and then causes the rotor (37) to retract and drain the refined mass from the defibrillator (30). 3. Swirl circulation flow defibrillator (30) for carrying out the method according to claim 1 or 2 with a rotor (37) and a stator (36) forming between them a truncated conical grinding surface, characterized in that it comprises regulating and driving means (51 and 64) for clearing the gap to zero at said intermediate surfaces, driving means (52) for rotating the rotor (37) at this gap of zero size with relatively high impact force to exert a grinding effect on the material loaded in the defibrillator for atomizing the liquid state, and recirculating devices in the defibrillator (30) to recirculate material discharged from said intermediate surfaces back into the defibrillator (30) until the fibers in this material are homogeneous and refined to the desired degree. Defibrillator according to claim 3, characterized in that it comprises automatic control devices (53) which are functionally associated with the defibrillator (30), for testing the completion of the pulp treatment and for discharging the pulp. Defibrillator according to claim 4, characterized in that said automatic control devices (53) comprise an automatic grinding degree testing device (55) in said defibrillator (30) for testing in the properties of this existing pulp, and a test device according to said test device. functioning electrical circuit (56) to test that the fibers have been properly refined and then to cause the rotor (37) to retract and drain the de-fibers (30). Defibrillator according to claim 4 or 5, characterized in that the automatic control devices (53) comprise an ammeter (57) for optically displaying for a mechanical the desired control of the impact force for a specified mass, and a limit switch (58) for to signal that the rotor (37) is in the fully retracted position, 7. Defibrillator according to any of the preceding claims 3, 6, characterized in that the rotor (37) and the stator (36) are sheeted and grooved and form a combined defibration and grinding device soin can treat unusual material such as hemp. , lump, leather and the like, and the device is provided with rotor blades (41) and stator tabs for mounting; comparing an insertion of the material to said intermediate surface, and said driving devices (52) being arranged to destroy the impact force of the rotor (37) surfaces where the gap between them is zero so as to exert a grinding effect on the material ± this intermediate surface to defibrate and refine the material. Defibrillator according to claim 7, characterized in that said blade-provided and fluted stator (36) contains alternating symmetrically arranged flow preventing latches and flow openings, whereby the stator remains balanced under a greatly enlarged refining shock force at a gap of magnitude n preventing a distortion of the shaft of the rotor (37). Defibrillator according to Claim 7 or 8, characterized in that said blade-provided and refflated stator (36) is operatively lined and guides the fibers in the pulp axially along said blade-provided and refflated intermediate surfaces from one end thereof to the other end, and that the stator (36) the tili shape is truncated at the large end and three-tab at the small end.