U.S. patent application number 13/008176 was filed with the patent office on 2011-10-20 for method for refining cellulose fibers in aqueous suspension as well as refiner filling to implement said method.
Invention is credited to Oliver Crasser, Markus Fursattel, Harald Hess, Hans-Herrmann Kleinschnittger, Michael Kramer.
Application Number | 20110253327 13/008176 |
Document ID | / |
Family ID | 41351635 |
Filed Date | 2011-10-20 |
United States Patent
Application |
20110253327 |
Kind Code |
A1 |
Crasser; Oliver ; et
al. |
October 20, 2011 |
METHOD FOR REFINING CELLULOSE FIBERS IN AQUEOUS SUSPENSION AS WELL
AS REFINER FILLING TO IMPLEMENT SAID METHOD
Abstract
The invention relates to a method for refining cellulose fibers
in aqueous suspension, using a plurality of refiner fillings having
refining edges, of which one is operated on at least one stator and
another is operated on at least one rotor, and the suspension to be
refined is processed between the two refiner fillings. A partial
flow of the suspension delivered to the outlet side flows back on
the back side of the refiner filling on the stator side, and then
flows through openings located between the refining edges of the
refiner filling on the stator side, and again into the refining
zone. This leads to particularly uniform and economical
refining.
Inventors: |
Crasser; Oliver; (Ulm,
DE) ; Fursattel; Markus; (Ravensburg, DE) ;
Hess; Harald; (Grunkraut, DE) ; Kleinschnittger;
Hans-Herrmann; (Weingarten, DE) ; Kramer;
Michael; (Graz, AT) |
Family ID: |
41351635 |
Appl. No.: |
13/008176 |
Filed: |
January 18, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/EP2009/004739 |
Jul 1, 2009 |
|
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13008176 |
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Current U.S.
Class: |
162/56 ;
162/261 |
Current CPC
Class: |
D21D 1/26 20130101; D21D
1/303 20130101; D21D 1/22 20130101; D21D 1/306 20130101 |
Class at
Publication: |
162/56 ;
162/261 |
International
Class: |
D21D 1/20 20060101
D21D001/20; D21B 1/30 20060101 D21B001/30 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2008 |
DE |
10 2008 046 592.5 |
Claims
1. A method for refining a plurality of aqueous suspended cellulose
fibers, said method comprising the steps of: carrying the plurality
of cellulose fibers in an aqueous suspension between a stator-side
refiner filling and a rotor-side refiner filling, said stator-side
refiner filling being located on a stator and including a first
face side and a first plurality of refining edges on said first
face side, said rotor-side refiner filling being located on a rotor
and including a second face side and a second plurality of refining
edges on said second face side, said stator and said rotor
providing a rotational movement relative to each other; pressing
said stator-side refiner filling and said rotor-side refiner
filling against each other; transferring a mechanical refining onto
said plurality of cellulose fibers; delivering said aqueous
suspension to an inlet side of said stator-side and said rotor-side
refiner fillings and then discharging again said aqueous suspension
from an outlet side of said stator-side and said rotor-side refiner
fillings; flowing a partial flow of said aqueous suspension which
was delivered to said outlet side through at least one hollow
chamber located on a backside of said stator-side refiner filling
and then through a plurality of openings which are located between
certain ones of said first plurality of refining edges of said
stator-side refiner filling and other ones of said first plurality
of refining edges of said stator-side refiner filling.
2. The method according to claim 1, wherein at least partially said
stator-side refiner filling is used, a plurality of edges of said
plurality of openings at least partially forming said first
plurality of refining edges.
3. The method according to claim 1, wherein at least partially said
stator-side refiner filling is used, at least partially said first
plurality of refining edges are formed by a plurality of refiner
bars which protrude from a refining plate which is equipped with
said plurality of openings.
4. The method according to claim 1, wherein said at least one
hollow chamber is at least one hollow space, said stator-side
refiner filling being used and being equipped with a plurality of
said hollow space and said plurality of openings, said aqueous
suspension being carried through said plurality of hollow spaces
from said outlet side to said plurality of openings.
5. The method according to claim 1, wherein said at least one
hollow chamber is at least one hollow space, said stator-side
refiner filling being used, being equipped with said plurality of
openings, and being connected detachably with a support in such a
way that at least one said hollow space is formed through which
said partial flow of said aqueous suspension is carried from said
outlet side to said plurality of openings.
6. The method according to claim 1, wherein said at least one
hollow chamber is at least one hollow space, said stator-side
refiner filling being used, being equipped with said plurality of
openings, and being connected detachably with a support in such a
way that a plurality of said hollow space are formed through which
said partial flow of said aqueous suspension is carried from said
outlet side to said plurality of openings.
7. The method according to claim 1, wherein a greater part of said
aqueous suspension is carried through said rotor-side refiner
filling from said inlet side to said outlet side.
8. The method according to claim 1, wherein said rotor-side refiner
filling is used, no return flow of said aqueous suspension being
generated on a backside of said rotor-side refiner filling, said
rotor-side refiner filling being equipped with a plurality of
refiner bars and a plurality of grooves located between said
plurality of refiner bars.
9. The method according to claim 1, wherein said at least one
hollow chamber is at least one hollow space, said aqueous
suspension flowing in a plurality of said hollow space being
directed by a plurality of hydraulic guide elements in a direction
toward said plurality of openings thereby one of reducing and
totally avoiding a plurality of swirls.
10. The method according to claim 1, wherein said aqueous
suspension flowing through said plurality of openings is directed
in a direction of said first plurality of refining edges by way of
a plurality of guide surfaces which limit said plurality of
openings whereby a plurality of swirls are one of reduced and
totally avoided.
11. A refiner filling, comprising: an inlet side for an aqueous
suspension; an outlet side for said aqueous suspension; a first
plurality of refiner edges located between said inlet side and said
outlet side, said first plurality of refiner edges being suitable
for refining said aqueous suspension; at least one hydraulic
connection between said outlet side and said first plurality of
refiner edges through which said aqueous suspension can get from
said outlet side to said first plurality of refiner edges, the
refiner filling being a stator-side refiner filling and being
configured for being used in a method for refining a plurality of
aqueous suspended cellulose fibers, said method including the steps
of: carrying said plurality of cellulose fibers in said aqueous
suspension between said stator-side refiner filling and a
rotor-side refiner filling, said stator-side refiner filling being
located on a stator and including a first face side and said first
plurality of refiner edges on said first face side, said rotor-side
refiner filling being located on a rotor and including a second
face side and a second plurality of refiner edges on said second
face side, said stator and said rotor providing a rotational
movement relative to each other; pressing said stator-side refiner
filling and said rotor-side refiner filling against each other;
transferring a mechanical refining onto said plurality of cellulose
fibers; delivering said aqueous suspension to said inlet side of
said stator-side and said rotor-side refiner fillings and then
discharging again said aqueous suspension from said outlet side of
said stator-side and said rotor-side refiner fillings; flowing a
partial flow of said aqueous suspension which was delivered to said
outlet side through at least one hollow chamber forming said at
least one hydraulic connection located on a backside of said
stator-side refiner filling and then through a plurality of
openings which are located between certain ones of said first
plurality of refiner edges of said stator-side refiner filling and
other ones of said first plurality of refiner edges of said
stator-side refiner filling.
12. The refiner filling according to claim 11, wherein a plurality
of said hydraulic connection are between said outlet side and said
first plurality of refiner edges and are configured for getting
said aqueous suspension from said outlet side to said first
plurality of refiner edges.
13. The refiner filling according to claim 11, wherein said at
least one hollow chamber is at least one hollow space and the
refiner filling includes an area of said backside, said at least
one hollow space being located in said area of said backside of the
refiner filling, being closed on said inlet side, being open on
said outlet side, and being connected hydraulically with said
plurality of openings which are located between said first
plurality of refiner edges.
14. The refiner filling according to claim 13, wherein the refiner
filling includes a plurality of said hollow space which are located
in said area of said backside of the refiner filling, are closed on
said inlet side, are open on said outlet side, and are connected
hydraulically with said plurality of openings which are located
between said first plurality of refiner edges.
15. The refiner filling according to claim 13, wherein said
plurality of hollow spaces are open on said backside.
16. The refiner filling according to claim 13, wherein said
plurality of hollow spaces are closed on said backside.
17. The refiner filling according to claim 11, wherein said
plurality of openings include a plurality of edges that at least
partially form said first plurality of refiner edges.
18. The refiner filling according to claim 11, wherein the refiner
filling includes a refining plate that is equipped with said
plurality of openings, the refiner filling being equipped on said
first face side with a plurality of refiner bars which protrude
over said refining plate.
19. The refiner filling according to claim 11, wherein said at
least one hollow chamber is at least one hollow space, the refiner
filling including a plurality of said hollow space and being
equipped with a plurality of guide elements in said plurality of
hollow spaces, said plurality of guide elements being positioned so
that a liquid flowing in said plurality of hollow spaces is
directed to said plurality of openings.
20. The refiner filling according to claim 11, wherein the refiner
filling includes a plurality of edges which limit said plurality of
openings, said plurality of edges being a plurality of guide
surfaces which are positioned so that a liquid flowing in said
plurality of openings is continuously directed to said first
plurality of refiner edges.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of PCT application No.
PCT/EP2009/004739, entitled "METHOD FOR REFINING CELLULOSE FIBERS
IN AQUEOUS SUSPENSION AND REFINER FILLING FOR PERFORMING THE SAME",
filed Jul. 1, 2009, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method for refining
aqueous suspended cellulose fibers whereby these fibers are carried
in an aqueous suspension between refiner fillings each of which are
equipped on their face side with refining edges and which are
located either on a rotor or a stator providing rotational movement
relative to each other and which are pressed against each other,
whereby mechanical refining is transferred onto the cellulose
fibers and whereby suspension is delivered to the inlet side of
refiner fillings and is then discharged again from outlet side of
refiner fillings.
[0004] 2. Description of the Related Art
[0005] It has been known for a long time that cellulose fibers,
that is virgin cellulose fibers or waste paper fibers, are refined
so that the subsequently produced paper has the desired
characteristics, especially strength, formation and surface.
Refining processes of the type considered here have utilized
refining tools which are often equipped with bars referred to as
blades and which can generally be screwed to the rotor or stator of
the refiner. The refiner tools are generally referred to as
fillings. The relevant machinery is known as refiners. The method
may typically be accomplished by disk refiners or cone
refiners.
[0006] Refiner fillings for refining of cellulose fibers, utilizing
refiner bars and grooves located between them are known for example
from DE 20 2005 007 551 U1.
[0007] DE 37 00 613 A1 describes disk refiners for processing of a
fibrous suspension in paper production, whereby rotor and stator
fittings are equipped with axially oriented openings. This divides
the suspension which is to be refined into many axial partial
flows, refines it and discharges it from the refiner. A similar
principle is also employed in the method addressed in DE 10 2004
039 986 A1.
[0008] What is needed in the art is a method of cellulose refining
which would provide uniform and particularly economical refining,
in other words one in which the desired technological refining
changes are as uniform as possible on all fibers.
SUMMARY OF THE INVENTION
[0009] The present invention provides a method for refining aqueous
suspended cellulose fibers whereby these fibers are carried in an
aqueous suspension between refiner fillings each of which are
equipped on their face side with refining edges and which are
located either on a rotor or a stator providing rotational movement
relative to each other and which are pressed against each other,
whereby mechanical refining is transferred onto the cellulose
fibers and whereby suspension is delivered to the inlet side of
refiner fillings and is then discharged again from outlet side of
refiner fillings, characterized in that a partial flow of
suspension which was delivered to outlet side flows through at
least one hollow chamber located on backside of stator-side refiner
filling and then through openings which are located between
refining edges of stator-side filling to refining edges of this
refiner filling.
[0010] The present invention further provides a refiner filling to
implement the method described in the preceding paragraph, with an
inlet side and an outlet side for suspension between which refiner
edges suitable for refining suspension are located, characterized
in that it has at least one, preferably several hydraulic
connections between outlet side and refiner edges through which the
suspension can get from outlet side to refiner edges. This refiner
filling is especially suitable for the method of the present
invention.
[0011] A considerable number of various refiner fillings has
already been developed, which differ from each other in regard to
blade width, number of blades and angle of blade edges relative to
the radius. However, the inventive method contributes to a
substantial improvement since it offers the possibility to direct
the suspension flow so that an additional possibility of influence
upon the refining effect provided by the refiner is created. In
particular, the return flows inside the stator-side fillings are
intensified. Already known fillings can here be used on the rotor
side. The effect can be explained as follows:
[0012] In a conventional blade type filling the grooves are to be
considered as flow channels for the suspension. Here it can be
assumed that due to the rotational movement of the rotor and the
fibrous stock suspension which is carried along by it, a strong
pressure build-up occurs from the inside radial areas to the
outside radial areas. Similar action occurs also in rotary pumps,
obviously in much stronger form. Because of this pressure
differential a backflow of the suspension occurs from radially
outside to radially inside in the non-rotating cavities of the
stator which are provided according to the invention. This backflow
may be influenced by selecting or changing the cross section of the
flow-carrying surfaces. On the path which is being taken by the
back-flowing suspension inside the cavities, a transfer can occur
through the openings which are located between the refining edges
of the stator-side refiner filling to the refiner edges of the
opposite refiner filling. Since these return flows lead to a repeat
of the refining processes, refining becomes more uniform which is
of particular advantage, both technologically and economically. The
inventive measures can strengthen this transfer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention will be better understood by reference
to the following description of embodiments of the invention taken
in conjunction with the accompanying drawings, wherein:
[0014] The invention is further explained with the assistance of
and reference to schematic drawings:
[0015] FIG. 1 shows the principle of the inventive method;
[0016] FIG. 2 shows implementation of the method--in this example
with a disk refiner;
[0017] FIG. 3 shows an example of inventive refiner filling
(section) viewed in direction of the back side;
[0018] FIGS. 4-9 show details regarding the various embodiments of
stator fillings;
[0019] FIG. 10 shows a top view of one sector of usable rotor-side
refiner filling;
[0020] FIG. 11 shows additional forms for the openings in the
stator refiner filling; and
[0021] FIG. 12 shows implementation of the method with a cone
refiner
[0022] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplifications set out
herein illustrate embodiments of the invention, and such
exemplifications are not to be construed as limiting the scope of
the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Referring now to the drawings, and more particularly to FIG.
1, there is shown a schematic sketch of the suspension flows which
occur when implementing the inventive method in a double disk
refiner with one rotor 9 and two stators 8 and 8'. Suspension S
which is to be refined is added in a central region of the double
disk refiner, gets between rotor 9 and stators 8 and 8' and is
carried toward the outside where it is refined. As a result of the
rotational movement a strong pressure buildup occurs on the path
from infeed side 5 to outlet side 6, in other words from radially
inside to radially outside. The result is that a partial suspension
flow S' returns from radially outside to radially inside. Since
stators 8 and 8' are equipped with openings in radial direction,
the suspension which flows back comes again into the refining zone.
The refined portion S'' flows out of annulus 17 through a
connection pipe.
[0024] The arrows for the suspension flows are drawn with hollow
tips in all drawings.
[0025] FIG. 2 illustrates a schematically depicted section of a
disk refiner suitable for the method. A refiner filling 1 is
mounted on a stator 8 and a refiner filling 2 on a rotor 9 which
are detachable by means of screws 12. The rotor-side refiner
fillings 2 are blade fillings which are equipped with refiner bars
7. In the illustrated example suspension S which is to be refined
is delivered to inlet side 5 of refiner fillings 1 and 2 through
the center of stator 8. This depiction shows an exaggeration of the
distance between refiner fillings 1 and 2. In operation it only
amounts to a fraction of millimeters. Suspension S passes the
conspiring refiner fillings 1 and 2, emerges again on the outlet
side, collects in annulus 17, and a refined portion S'' leaves
annulus 17 via an appropriate connection pipe. A partial flow S' of
the suspension flows through a hollow chamber 14 located on
backside 11 of the stator-side refiner filling 1 and then through
openings 15 which are located between refining edges 3 of
stator-side refining fillings 1 to refining edges 3 of this refiner
filling 1. Such surfaces are considered to be refining edges
which--in conspiring together with refining edge of an opposing
filling (generally rotor with stator fillings)--transfer the
refining effort to the fibers. Refining fillings 2 on the rotor
side are equipped with refiner bars 7 which represent their
refining edges. No return flow of suspension is generated on the
backside of the rotor fillings. Rotor 9 is driven by a shaft 13.
Generally known means with which power is generated to press the
two refiner fillings against each other are not illustrated.
[0026] FIG. 3 illustrates a refiner filling 1 suitable for the
method, shown in direction of backside 11 (see FIG. 2). In order to
support refining plate 12 which is equipped with openings 15 a
support 10 is provided which can be welded, soldered or detachably
connected with refining plate 12. It may also form a single
component with refining plate 12, for example as shown in FIG. 5.
Support 10 is open on its radial outer side, whereby the support
elements are spoke-like, and are equipped with an enclosed ring on
their radial inside. In between are hollow spaces 14. The design is
further clarified by the cross section of the side view in FIG. 4,
whereby here refining plate 12 and support 10 consist of different
components. Refining edges 3 are formed by the edges of openings
15.
[0027] FIG. 6 illustrates an example where refining edges 3' are
formed by refiner bars 7 which protrude from a refining plate 12'
which is equipped with openings 15. This may offer advantages if a
great number of refining edges 3' are required. In addition,
protruding refiner bars 7 may possibly be better protected against
wear and tear. It is advantageous to then close off the grooves
located between the refiner bars in radial direction toward the
outside.
[0028] Grinding plate 12'' in FIG. 7 is not equipped with the
hollow spaces 14 which are open toward outlet side 6. These hollow
spaces 14 are instead integral in stator 8. Refining plate 12''
therefore represents refiner filling 1 which can be screw connected
with stator 8.
[0029] Advantageous measures can be taken in order to take care of
the flow of partial flow S', especially in order to avoid troubling
swirls and stagnation points. In particular, additional hydraulic
guide elements and guide surfaces are to be provided for this
purpose which, based on their shape, allow an as constant and an as
loss free transportation of the suspension as possible from outlet
side 6 to refining edges 3 or 3'. Several options which can be used
individually, or in combination with each other, for this purpose
are shown in FIG. 8 and FIG. 9. Here, the radial outside of
refining plate 12''' is equipped with a rounded protruding turning
element 18 which can also have an asymmetrical shape as shown in
the detail in FIG. 9. In addition, hollow spaces 14 may be equipped
with guide elements 19, 20, and 21 which are aligned in a way so
that the liquid flowing in hollow spaces 14 is rerouted to openings
15. The transitions of hollow spaces 14 to openings 15 can be
rounded with the assistance of guide surfaces 22, 23 and 24 in a
way so that the flow can be diverted without a break. The depiction
in FIG. 8 shows a few examples, whereby the pitch (deviation
opposite the radius) of openings 15 and their edges cannot be
recognized.
[0030] It must also be considered that a wear and tear zone 25
exists on the upper areas of refining edges 3 where possibly the
flow caretaking measures would not be advantageous.
[0031] FIG. 10 shows the section of a generally known refiner
filling 2 which can be utilized on the rotor side when implementing
the method. It contains a plurality of refiner bars 7 between which
grooves 26 are located for the transport of suspension S from
infeed side 5 to outlet side 6. Refiner bars 7 are often combined
into groups where they are positioned parallel to each other. In a
favorable fabrication this would allow for a large number of
refiner bars, located at a selectable angle of intersection with
the radius.
[0032] As shown in FIG. 3 the shape of openings 15 which are
located between the refining edges can be slotted, at an angle to
the radius or precisely in radial direction. FIG. 11 shows examples
of additional forms such as round holes or polygons/squares.
Variations in placement and size of openings 15 provide
possibilities to influence the distribution of the return flow of
the suspension. For example, openings which are located closer to
the inside in radial direction can be larger in order to equalize
lower pressure of the return flow in that location.
[0033] The current invention not only improves refining with disk
or double disk refiners, but also with cone refiners whereby the
effect with a steep cone angle is greater than with a flat one.
FIG. 12 shows the method schematically utilizing a cone refiner
where rotor 9 is truncated and carries the refiner filling on its
circumference. The conspiring refiner filling is located at the
periphery of the rotor and is connected with truncated stator 8.
Suspension S is carried in axial direction between the fillings
from infeed side 5 to outlet side 6. The steeper the cone, the
greater the pressure build up which is being produced. It can be
clearly seen that the refining fillings of stator 8 are provided
with hollow spaces 14 and openings 15 in order to return a partial
flow S' from outlet side 6. The illustration in FIG. 12 is greatly
simplified, is however sufficient to explain the principle of the
invention with this example.
[0034] The method can also be arranged so that in addition to the
measures, in particular in combination with the measures described
in the claims the flow cross section in grooves 26 of refiner
filling 2 on the rotor side is changed by different groove width
and/or depth. The groove width and/or groove depth therefore
increases or decreases from the inside toward the outside. In
particular this allows for the pressure build up through rotor 9
and thereby also the return flow in stator 8 to be influenced and
to facilitate the transfer of return flow of suspension into the
refining zone.
[0035] While this invention has been described with respect to at
least one embodiment, the present invention can be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains and which fall within the limits of
the appended claims.
* * * * *