FI110521B - Method and apparatus for milling wood fiber pulp - Google Patents

Description

110521

The present invention relates to a method for grinding a pulp or a similar pulp 5, wherein the pulp is fed relative to one another between the blade surfaces of a conical refiner which is rotated about one end. The invention also relates to a cone grinder for applying said method.

The pulp is treated in a refiner where the fibers or bundles of fibers are ground between the blades moving relative to one another in the refiner. The fibers accumulate on the leading edge of the moving blade and grind as the edges pass each other. Grinding is an important part of the papermaking process and affects almost all properties of the finished paper and the operation of the paper machine.

15 Conical refiners are commonly used because of their greater refining power. The conical refiners comprise two nested conical blade surfaces, one of which is a rotor, i.e. a movable blade surface, and the other is a stator, i.e. a fixed blade surface. The rotating rotor of the tapered grinder enhances the movement of the fibers across the blade for improved milling efficiency.

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Due to the conical shape of the cone grinder, the surface of the blade surfaces increases as it moves from the feed end of the blade slot towards the outlet end. Correspondingly, the volume of the blade gap between the blade surfaces also increases as it moves away from the feed end of the blade slot. As a result, the mass distribution of the pulp fed at the end of the slot is not uniform but close to; v 25 feed heads has more mass per unit volume than near the cutter slot: # 4: Discharge end, which does not grind evenly across the cutter surfaces.

This problem has now been solved by the method of the invention for wood pulp. or a pulp of this kind. In the process according to the invention, wood fiber. 30 cores are fed to the blade slot in addition to the blade slot feed end provided on the blade surface

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the supply apertures.

; 'T 1 The method of the invention smoothes the mass distribution in the longitudinal direction of the slit of the cone grinder, thereby achieving a more even milling than the known:' 1 ': 35 methods. Further, when grinding an uneven base mass (i.e., a mass with a wide particle size: 1 "; particle size distribution), the process according to the invention achieves uniformity. better than traditional methods.

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In the method according to the invention, the feed openings are preferably arranged on a blade surface acting as a rotor.

Said inlet openings are preferably arranged on the blade surface such that the openings are axially spaced in one or more zones. According to an embodiment of the invention, the feed openings are located in two zones, for example, the first feed openings being at least 15%, preferably at least 20% and at most 30%, preferably no more than 25% of the axial length L of the blade slot and The apertures are located at a distance of at least 30%, preferably 35%, and at most 45%, preferably 40%, of the blade slot feed end from the axial length L of the blade slot.

The number of inlets depends on the dimensions of the cone grinder as well as the dimensions of the openings. According to a preferred embodiment, each zone has 15 equal number of inlets and the number of said inlets is at least 4, preferably at least 6 and at most 10, preferably at most 8.

The inlet openings are shaped and sized so that the openings do not interfere with the operation of the blades or the mass flow back. According to one embodiment, said feed holes 20 have a length of at least 10%, preferably at least 12%, and at most 20%, preferably no more than 17%, of the axial length L of the blade slot and a width of at least 2.0%, preferably at least 2.5%, and up to 4.0%, preferably up to 3.5%, of the axial length L of the blade slot. In this case, the blade slot is a rectangle with rounded corners.

: J 25: ": In the process, the feed pressure of the pulp is at least 0.5 bar, preferably at least 1 bar, and at most 5 bar, preferably at most 3 bar (1 bar = 100 kPa). the consistency of the feed is at least 2%, preferably at least 3%, and at most 5%, preferably at most 4%.

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The invention further relates to a taper mill for applying a method which: -; The refiner comprises conical blade surfaces which are rotatable in relation to each other, a feed port through which the pulp is fed into the blade gap between the blade surface surfaces of the refiner at its end, and one or 35 more mass feed apertures followed by the blade surface. Preferably, a plurality of feed openings are provided on the blade surface of the refiner as axially staggered zones.

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According to a preferred embodiment of the invention, the cone angle of the cone refiner is 10-30 °, very preferably the cone angle of the refiner is 15-25 °. In this case, the cone refiner has a blade cone length of 300-640 mm and the cone refiner is one-sided.

The invention will now be described in more detail with reference to the accompanying drawings, in which: Figure 1 shows a conical refiner according to the invention, and Figure 2 shows a projection on the plane of the drawing of a conical rotor blade surface of the refiner.

The cone grinder shown in Figure 1 consists of a stationary body 1, an associated outer cone or stator 2, an inner cone 15 or rotor 4 supported by a rotary shaft 3, a stator and rotor nested truncated conical blade surfaces 5 and 6 and a blade surface 5 and 6. , which is a longitudinally expanding space having an axial length L. The cone angles of the stator 2 and the rotor 4 are equal so that the blade slot 7 has a constant width over the entire length of the refiner. The cone grinder shown below consists of a pulp feeder 20 located at a narrower end of the cone, a pulp outlet 9 which leads; To the outlet duct 10 and the internal flow path 11 of the rotor 4 leading from the end of the mass rotor 4 to the inlet openings 12 and 13.

Figure 2 shows one possibility of positioning the blades 14 on the rotor blade surface 25 6 and the location of the feed openings 12 and 13 with respect to the blades 14. The feed openings 12, 13 are located on the rotor blade surface 6 in two zones 12, 13, where the openings are equally spaced around the rotor circumference. The sector shown in the surface pattern has two apertures, thus showing one way to position them relative to each other.

. . The blades 14 shown in Fig. 2 may be at or at a right angle to the conical sheath lines and their shape and distance may be varied, as may the blade patterns of the various zones.

»•; · ·; During milling, the rotor 4 is brought into continuous rotary motion and pulp * 35 is fed to the refiner at a feed pressure of 0.5-5 bar, preferably 1-3 bar, from the feed * 8 of the pulp * and through the inlets 12 and 13 of the blade surface 6. 100 kPa). The consistency of the pulp to be fed is 2-5%, preferably 3-4%. The pulp moves axially forward in the blade slot 7, whereby the fibers accumulate on the leading edge of the movable blade 4 110521 and grind as the edges pass one another. The mass distribution is substantially uniform throughout the blade area due to the mass fed through the feed openings 12 and 13 provided on the rotor blade surface 6.

It will be apparent to one skilled in the art that the method and apparatus for grinding wood fiber pulp according to the invention are not limited to the above example but may vary within the scope of the following claims.

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Claims (11)

1. Förfarande för att Mala träfibermassa eller dyllik, varvid mass inmatas mellan inbördes roterande bettytor (5, 6) i en konrafinör frän änden (8) av bettspalten (7), kännetecknat av attess dessutom inmatas i bettspalten (7) - y. selöppningar (12, 13) inrättade nap bettytan (5, 6). 25 • · A method for grinding pulp or similar pulp, wherein the pulp is fed relative to one another between the blade surfaces (5, 6) of a conical drum at the end (8) of a blade slot (7), characterized in that the pulp is fed into the blade surface (5, 6) from the tracked feed openings (12, 13). Förfarande enligt patentkrav 1, kännetecknat av att nämnda tillförselöppning-ar (12, 13) befinner sig axialt avtrappade end bertytan (5, 6), i eller flera Zoner, * '· företrädesvis i zoner. t »« · * • · · * »· v * 30 3. Förfarande enligt patentkrav 1 eller 2, kännetecknat av att det i shade zon firms lika mga tillförselöppningar (12, 13). • * * · »# * · *": 4. Förfarande enligt nagot av föregäende patentkrav, kännetecknat av att första tillförselöppningar (12) befmner sig pä et avständ frän bettspaltens (7) matarände '... 35 (8) som är mellan 15-30%, företrädesvis mellan 20-25%, av bettspaltens (7) axiala '·; ·' längd (L) och att andra tillförselöppningar (13) befmner sig pä ett avständ frän bett- *. ':: Spaltens (7) ) mammal migration (8) som är mellan 30-45%, företrädesvis mellan 35-40%, av: ***: bettspaltens (7) axial längd (L) I t I 7 110521 Method according to Claim 1, characterized in that said bore openings (12, 13) are disposed axially stepped on the blade surface (5, 6) in one or more zones, preferably in two zones. Method according to claim 1 or 2, characterized in that each zone has the same number of inlet openings (12, 13). 15 Method according to one of the preceding claims, characterized in that the first feed openings (12) are located at a distance of 15-30%, preferably 20-25%, of the blade slot (7) from the axial length (7) of the blade slot (7). L) and that the second feed openings (13) are located at a distance of 30-45%, preferably between 35-40%, from the feed end (8) of the blade slot (7) about the axial length (L) of the blade slot (7). 5. Förfarande enligt nägot av föregäende patentkrav, kännetecknat av att de nämnda tillförselöppningars (12, 13) sluggish 10-20%, företrädesvis mellan 12-17%, av bettspaltens (7) axial slab (L) och att tillförselöppning , 13) 5 bredd mellan 2.0-4.0%, företrädesvis mellan 2.5-3.5%, av bettspaltens (7) axial slope (L). A method according to any one of the preceding claims, characterized in that said inlet openings (12, 13) have a length of between 10 and 20%, preferably between about 25, 12 and 17% of the axial length (L) of the blade slot (7) and that the inlet openings (12, 13) have a? t:? width of between 2.0 and 4.0%, preferably between 2.5 and 3.5% of the axial length of the blade slot (7). (L). Process according to one of the preceding claims, characterized in that the feed pressure of the pulp is between 0.5 and 5 bar, preferably between 1 and 3 bar (1 bar = 100kPa). <1 5 110521 6. Förfarande enligt face av föregäende patentkrav, kännetecknat av att mas-sans matningstryck at 0.5-5 bar, företrädesvis mellan 1-3 bar (1 bar = 100 10 kPa). 7. Förfarande enligt nägot av föregäende patentkrav, kännetecknat av att massan som mäsäs in i konraffmören haren consistency som 2-7%, företrädesvis mellan 3-4%. 15 A method according to any one of the preceding claims, characterized in that 1; 1 ': that the consistency of the pulp fed to the cone grinder is between 2% and 5%, preferably between 3% and 4%. »1,, 8. A cone grinder for grinding pulp or similar pulp, which comprises» 1 '· conical blade surfaces (5, 6) which can be rotated 110521 with respect to each other and a feed unit (8, 11) through which the pulp fed to the blade slot (7) between the blade surfaces (5, 6) of the refiner at its end (8), characterized in that pulp feed openings (12, 13) are provided on the blade surface (5, 6) of the refiner. 8. Konisk raffinör för malning av träfibermassa eller dylt, weave innefattar konniska inbördes roterbara bettytor (5, 6), samt et matarör (8, 11), color in mass frän aänden (8) av bettspalten (7) bettytoma (5, 6), kännetecknad av att tillförselöppningama (12, 13), for mass mass inrättade Pä konraffinörens betty (5, 6). 20 A rotating device (12, 13) for inserting a plug (5, 6) and a plug (6) for inserting a rotor. A refiner according to claim 8, characterized in that said feed openings (12, 13) arranged in the blade surface (5, 6) are disposed on the blade surface (6) acting as a rotor. Refiner according to one of Claims 8 to 9, characterized in that the inner cone (4) of the refiner 10 comprises a pulp for the pulp which flows from its end to the feed openings (12, 13) in the conical blade surface (6). A refiner according to any one of claims 8 to 10, characterized in that the cone refiner has a cone angle of 10-30 °, preferably 15-25 °. 15 A refiner according to any one of claims 8 to 11, characterized in that the conical refiner is one-sided. 20 10. A rafinör enligt face of the patent patent 8-9, a rotation of an att raffinörens inre kon (4) innefattar en avflödesväg (11) för massan som skall malas, som leder frän dess ände account tillförselöppningama (12, 13) end (6). • <· t I v : 11. Raffinör enligt face face krav 8-10, bending angle av att konraffinörens v: 30 spetsvinkel v 10-30 °, företrädesvis 15-25 °. 1 »* * Raffinör enligt nägot patentkrav 8-11, kanknetecknad av att konraffmören är • ''; lager as a head bind. »* I *»