Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
  • D21D1/00—Methods of beating or refining; Beaters of the Hollander type
  • D21D1/20—Methods of refining
  • D21D1/34—Other mills or refiners
  • D21D1/36—Other mills or refiners with vertical shaft
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
  • D21D1/00—Methods of beating or refining; Beaters of the Hollander type
  • D21D1/20—Methods of refining
  • D21D1/34—Other mills or refiners
  • D21D1/38—Other mills or refiners with horizontal shaft

Definitions

• the invention relates to a method for fiber treatment according to the preamble of claim 1.
• Process for fiber treatment of the above Kinds are generally also referred to as grinding processes. It has long been known that pulp fibers have to be ground so that the paper subsequently produced from them has the desired properties, in particular strength, formation and surface. By far the most frequently used grinding processes use grinding surfaces which are provided with strips known as knives. The corresponding machines are mostly called knife refiners. For special cases, grinding processes are also used in which at least one of the grinding surfaces is knife-free, so that the grinding work is transmitted by friction or shear forces.
• the effect of the method can be controlled over a wide range by changing the grinding parameters, and in addition to the amount of grinding, a distinction is made in particular as to whether a more cutting or more fibrillating grinding is desired. If pulp fibers are processed by the known grinding processes, their resistance to dewatering increases with increasing grinding. A common measure of drainage resistance is the Schopper-Riegler degree of grinding.
• the invention is based on the object of providing a method for treating pulp with which it is possible to change pulp or paper fibers in such a way that the strengths of the paper produced therefrom are increased.
• the increase in dewatering resistance that occurs should be at least less than in known grinding processes.
• the new grinding process essentially works in such a way that grinding shear stress on the cellulose fibers is largely avoided. This essentially achieves three important advantages over the known grinding processes:
• the fiber surface is not or significantly less fibrillated.
• the specific grinding work to achieve the desired strength is generally less.
• FIG. 2 Schematic: A device for performing the method
• FIG. 4 schematically in the position of use: Another device for
• FIG. 1 can be seen as a top view of part of a device that is particularly suitable for carrying out the method be considered. However, no technical-constructive details are shown.
• the grinding surface 1 is located on the outer circumference of a rotating grinding body 9.
• the grinding surface 2, as the inside of a likewise rotating grinding drum 8, carries on its inside the fibrous material F to be ground, that is to say the aqueous suspension containing the paper or cellulose fibers. Due to the centrifugal forces, it is evenly distributed on the grinding surface 2 and rotates on it.
• the peripheral speed of the grinding element 9 is indicated by an arrow 6 and that of the grinding drum 8 by an arrow 7.
• the kinematics of these two grinding surfaces is such that at point 5, where the two grinding surfaces come closest, there is at most a very low relative speed between the fibrous material F and the grinding surfaces in the direction of the main movements of the grinding surfaces.
• the main directions of movement arise from the movement of the grinding surfaces due to the drive.
• the grinding body 9 rolls here on the inside of the grinding drum 8.
• the axis of rotation of the grinding element 9 is parallel to that of the grinding drum 8 and can be fixed in space.
• the actual grinding zone 3 begins at the point at which the grinding surface 1 dips into the layer of the fibrous material F.
• the grinding body 9 is pressed against the grinding surface 2 with the force P here. The grinding effect can be adjusted by changing this force.
• the grinding surface 1 is here provided with grooves 4, the effect of which cannot be compared with that of knives known from knife refiners, in which the knives are moved relative to one another at high speed.
• the grooves 4 in cooperation with the counter surface, generate pressure pulses which serve, for example, to absorb water from the fibers. They also ensure the transport of the fibrous material F through the grinding zone 3.
• the grooves can run over the entire axial length of the grinding body, but they can also be interrupted. Depth t and width u should generally be at least 2 mm. Deviations from the rectangular profile shown here are also conceivable, as shown by way of example in FIG. 3 using a trapezoidal profile.
• a device for performing the method could basically be constructed as shown in FIG. 2 in the position of use.
• a horizontally arranged grinding drum 8 can be seen, which is set in rotation via the drive 11.
• Within this grinding drum there are several grinding bodies 9 which - as already described - are moved in such a way that a rolling movement is formed at the contact points with the grinding drum 8.
• the grinding media 9 are set in rotation by the drive 10, their axes of rotation being vertical and fixed in space.
• the added fibrous material F can be ground in batches with such a device and removed after the grinding process as ground fibrous material F '. If such a device is to be operated continuously, precautions must be taken which bring about a constant throughput of the fibrous material, so that uniform grinding takes place.
• FIG. 4 Another possibility for carrying out the method is shown in FIG. 4, in which the center lines of the grinding drum 8 and the grinding element 9 lie horizontally.
• This device allows continuous grinding what However, this presupposes that the desired grinding is achieved with just a few passes through a grinding zone.
• a wide layer of the fibrous material F to be ground is introduced into the stationary grinding drum 8 in such a way that it runs down on the inner wall of the grinding drum due to gravity.
• the grinding element 9 rolls on the inner wall of the grinding drum 8 such that the rotational movement (directional arrow 6) of the grinding element 9 about its axis is superimposed with a rotational movement (directional arrow 6 ') of the axis of the grinding element 9 about the center line of the grinding drum 8.
• such a device contains a plurality of grinding media 9 which are mounted on a rotating frame.
• the grinding media can run against the flow of the pulp (as drawn here) or follow it.
• FIG. 5 The improvement that can be achieved by the new method is indicated on a schematic diagram according to FIG. 5.
• This diagram shows the degree of grinding (arrow 12), plotted over the tearing length (arrow 13).
• Curve 14 shows the result of a conventional knife grinding and curve 15 shows a result achieved by the new method. It can easily be seen that in order to achieve a desired high tearing length, the new process produces a significantly lower degree of grinding. This diagram is only intended to show a general trend.

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• 2002
  • 2002-08-13 DE DE10236962A patent/DE10236962A1/de not_active Ceased
• 2003
  • 2003-07-30 CN CN03819044.3A patent/CN1697902A/zh active Pending
  • 2003-07-30 US US10/523,063 patent/US20070006984A1/en not_active Abandoned
  • 2003-07-30 JP JP2004533296A patent/JP2005535799A/ja active Pending
  • 2003-07-30 EP EP03793666A patent/EP1521883A1/de not_active Withdrawn
  • 2003-07-30 RU RU2005106869/12A patent/RU2309211C2/ru not_active IP Right Cessation
  • 2003-07-30 WO PCT/EP2003/008445 patent/WO2004022843A1/de not_active Application Discontinuation
  • 2003-07-30 BR BR0305765-8A patent/BR0305765A/pt not_active IP Right Cessation
  • 2003-07-30 AU AU2003258551A patent/AU2003258551A1/en not_active Abandoned
• 2004
  • 2004-03-30 NO NO20041310A patent/NO20041310L/no not_active Application Discontinuation

Non-Patent Citations (1)

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