DE3135507A1 - METHOD AND APPARATUS FOR REFINING FIBER FABRIC IN A DISC DESIGNER - Google Patents

Description

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DESCRIPTION

The invention relates to a method and an apparatus for grinding lump-shaped, preferably lignocellulosic Output. The apparatus is fitted with grinding members rotating around one another in a housing equipped, the facing surfaces grinding surfaces for dividing the ground material into finely divided form form. An essential one. The area of application is apparatus of this kind, the pulpers or refiners for the manufacturers! - ■ processing of fiber or paper stock from vegetable raw materials in the form of wood chips, sawdust, bagasse ο the like. to be named. Apparatuses of this type have at least two disk-shaped members rotating around one another, including it is to be understood that these grinding surfaces cooperate with one another and extend in the radial direction.

From DE-OS 290 541 9 is known to carry out this refining surfaces with a radially inner portion with principal extension in a radial direction and a radially outer portion with principal extension in the axial direction _s in which at least the outer portion of both grinding surfaces. serves as a grinding gap and is shaped for this purpose with combs, ribs and grooves. · ■

The one disk link can be n-ichtuml to end as a whole be or, as proposed in EU-OS 0 016 743, be divided into two elements, of which the outer is non-circumferential, while the inner is opposite to revolves around the disk member rotating as a whole. Through this structure of a fine shredder or raffiaeur divided the gap between its disc-shaped members into an inner and an outer section, the inner section having a central inlet opening for the property to be married and in which this is proportionate weak centrifugal force can be exploited to the maximum for discharging the goods to the outer section, and this through appropriate dimensioning of diameter, speed and grinding pressure a very high efficiency and good '

Dividing capacity with at the same time proportionate low power consumption. For example, these factors have an effect of 10,000 kWh with a feed

. . and more also the consequence that in the grinding gap steam from liquid (water) present in the grinding stock is under a Vapor pressure is generated which is strong enough to overcome the resistance in the grist and make its way to be found out of the gap between the meals. The steam outlet is partly opposite and partly in the The direction of flow of the grist is going on has a

disruptive effect on the grinding process. The outflowing Steam makes it difficult to feed the goods into. ■ the grinding zone that generates the steam and shortens the dwell time for the ground material in the outer grinding zone.

The invention aims to improve the efficiency and performance of a grinding apparatus as described above Type by switching off the unfavorable effect of the steam generated in the grinding gap on the grinding material flow in the Improve gap. This is essentially due to this achieved that "the steam located in the grinding gap from the grinding stock counter to the action of the centrifugal force With the aid of inwardly directed grinding members provided in the rotating grinding element which forms the radially inner grinding surface Channels, is deposited before the ground material leaves the grinding gap at its outer peripheral end. One for performing Apparatus particularly suitable for the process is characterized in that it has the radially inner grinding surface of the .outer meal Opposite grinding element with inwardly running outlet channels for the separation of steam from the ground material the effect of the centrifugal force before the grist leaves or enters this outer Mahlspalttei1 piece is provided.

Since the steam outlets from the surrounding inner, the ". axially inclined split part delimiting grinding ■ begin on the surface, the vapor is separated from the grist if this is caused by the action of the centrifugal

force lingers in the grinding gap and with further breakdown into fibers or fibrils to the outer circumference of the Gap is advanced. The braking effect, which according to the The above mentioned writings are exerted on the goods by dividing the centrifugal force into two components of which the one acting at right angles to the grinding surface is larger than that in the direction of the grist flow active component, the dwell time for the ground material in the »grinding zone and thus the grinding capacity can be reduced bring the cheapest value.

Other purposes, distinguishing properties and advantages of the invention emerge from the 'following, • "With reference to the accompanying drawings, description of some embodiments of a 'According to the invention executed meal ap.parats. Show it:

1 shows a first embodiment of the according to the invention designed grinding apparatus partially in a vertical longitudinal section,

2 shows a part of this apparatus on a larger scale,

3 and 4 are longitudinal sections through two modified embodiments of the grinding apparatus.

An apparatus housing is denoted by 10 in the drawings. _It houses a rotating grinding element or rotating grinding disk, generally designated 12, and a non-rotating grinding element, generally designated 14. The rotating grinding disk sits on a horizontal shaft 16 which is in a known manner in a part 18 of the base frame of the apparatus. The two grinding members are clad in a known manner on their sides facing one another with rings or segments 20 and 22, which together form a grinding gap 24. This grinding gap extends in a plane at right angles to the axis of rotation of the shaft 16 and forms an inner or primary grinding zone. The ground material, for example in the form of preheated wood chips or chips, is fed in by a screw 26. This snail

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is located in a central, connected to the housing 10 Inlet nozzle 28. The grist is fed from the Screw to a feed zone 30 on the radial inside of the grinding gap and from there in an outward direction between the grinding segments 20 and 22. On the screw 12 there is also a rotating throwing member 32, from which the Grist introduced by the screw 26 is diverted to the feed zone 30.

The part 18 of the base frame can, in addition to the support bearings for the shaft 16 and its rotation, servo

■ contain motor links that allow axial displacement of the Allow disk 12 and at the same time generate the axial grinding pressure between the two grinding members. This servo, The motor can furthermore be set up in such a way that with its help the width of the cutting gap 24 can be reduced to a desired one Set the value and keep it there. The part 18 with its members is in itself e.g. by the US Pat. No. 3,212,721 previously known and will not be described in detail here, in particular because it is for the present invention is meaningless.

In the axial direction outside the radial grinding gap 24, a grinding gap 34 is formed which extends in the axial direction and has a conical shape in the illustrated exemplary embodiments. The gap 34 forms, as ■ in the Swedish Offenlegungsschrift mentioned at the beginning is explained in more detail, an angle to the plane through the inner gap 24 and thus at right angles to the axis of rotation of the rotating grinding element 12, which is larger than 45 °, as shown schematically in the drawing figures. At the This angle should ideally be greater than 60-70 °. With .

Particularly good results have been achieved with values between 75 ° and 82.

As best seen in Figures 2 and 3, the inner grinding surface of gap 34 is made up of grinding segments 38, which are firmly connected to the rotating grinding disk 12. The outer grinding surface in the radial direction of the gap 34 is formed by segments 40 on a

with the shaft equidistant ring element 42 sit. the Segments 40 thus have an internal or concave gap surface 44, which the outer gap surface 46 of the circumferential Segments 38 surrounds. The relatively fixed ring element 42 is independent of the setting for the purpose of regulating the width of the grinding gap 34 between the two gap surfaces 44, 46 the distance between the grinding members 12, 14, which determine the width of the gap 24, in the axial direction movable. For this purpose, the ring element 42 is on the non-

10. centered rotating grinding member 14 and with an annular Piston 48 is provided, which is axially displaceable with a sliding fit in a cylindrical annular chamber 50 ′. These Annular chamber is in the stationary housing 10 or in one this associated cover 51 is formed. The inner space

1.5 52 of the chamber 50 is a means under pressure, e.g. steam, Air, water, oil or the like. fed through a line 54. This pressure is high enough to make the crazy opposite Direction acting component of the grinding pressure exerted on the grinding stock as well as the pressure of the between 'To overcome the steam generated by the grinding surfaces. The movement of the non-rotating ring element 42 and the Ririg piston 48 in the direction of the orbiting grinding member 12 is by a number of around the perimeter of the piston distributed spindles 56 limited, fixed in the piston sit and take part in your exterior. End formed threads 58 with Eins.tel Imuttern 60 are in engagement. This in- " lock nuts are operated by a common gear, -that a sprocket 62 on each nut, a drive wheel 64 seated on the shaft 66 of a servomotor 65, and a includes chain 68 running over these wheels. Between· Adjusting nuts and the housing '10 bearings 70 are provided. Each of the spindles 56 can have a continuous inner channel 72, which is connected to a supply line 74 at one end of cooling liquid under pressure, such as water, in connection ste.ht and at its other end with channels 75, which in the ..Milling gap open out, expediently at the transition between its two zones 24 and 34. This allows the outer. Grinding zone 34 liquid is supplied to the grist

to cool and to replace the generated steam 'in such a way that no overheating of the grist occurs.

In the radial grinding zone 24 this is from the feed zone 30 coming meal well subjected to the full extent of the effect of centrifugal force in the outward direction. In In this inner grinding zone, the grinding stock is beginning to be crushed. When it is then in the outer grinding zone 34 Once inside, the centrifugal force increases to a very high degree, but their effect on the advancement of the goods is still considerably reduced. This gives you a balance for the strength of the centrifugal force, which otherwise increases with the radius, which has the consequence that the flow velocity of the grist decreases in the direction of flow and thus the Processing time is extended. The one on the grist acting centrifugal force has a right angle to the:

Generating the gap 34 acting component, which is from the · non-rotating, adjustable ring element 42 added and a component acting in the direction of flow that only accounts for a smaller part of the total centrifugal force matters.

The grinding segments 20, 22 and 38, 40 are in a known manner with their surfaces facing one another Combs or ridges shaped through in the direction of the grist flow extending grooves from each other are separated, as well as with these channels dividing crossbars.

When the grinder is in operation, the grist, like the wood shavings, especially in the outer, inclined grinding gap zone 34, a strong processing the resulting separation of the fibers from each other or exposure of fibrils due to the high, from the outside to the Use of the grinding pressure and the high peripheral speeds as a result of the large increase in diameter in the outer grinding zone. The great energy supply has to As a result, steam under high pressure is generated, which exerts a pressing effect on the flow of grist and thus more or less completely the braking of this flow caused by the axial extension of the grinding zone

. cancels. According to the invention are now in the grinding segments 38 of the rotating grinding disk 12 channels 76 are provided, which extend radially inward from the grinding gap zone 34. A number of such channels are preferably across the grinding gap in the direction of flow of the grist distributed, wherein the individual channels open into a common • collecting channel 78 for routing the steam. channels 76. with collecting channel 78 can be distributed over several locations around the circumference of the rotating grinding disk 12.

The steam generated in the grinding gap now flows inwardly into the channels 76 against the direction of the centrifugal force and becomes thereby separated from the grist, which, thanks to the high value of the centrifugal force, is much longer than it usually does The case would be, remains in the grinding gap and slowly moves towards its outer circumference as grinding continues moves and finally exits there. The finished ones Fibers are in the chamber 80 of the under pressure ·. standing grinding housing 10 and swirled by a Outlet 82 discharged.

In the embodiment according to FIGS. 1 and 2 open the collecting duct or ducts 78 into the chamber and there the steam is brought together again with the fiber flow. ·. ·

In the embodiment according to FIG. 3 this is the Housing 10 surrounding grinding elements is divided into two chambers with the aid of a sealing ring 82. This sealing ring 82 is fastened to the housing by means of screws 84 and extends from there into an annular recess 86 into the circumferential disk 12 and forms this recess opposite sealing surfaces 88. These surfaces can through a channel 90 a medium such as water can be supplied which is at a higher pressure than that in the two Chambers of the housing prevailing pressure. As a result, the housing 10 is divided into a chamber 80 through which exits the finished milled fiber material, and a Chamber 92 with an outlet 94, to which the steam via channels 96, 98 provided in the disk 12 from the collecting

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channel 78 escapes. Any not finished Grist, which follows the separated steam, leaves now collect easily and lead back into the grinding gap. There is also one in the inner radial grinding zone 24 Steam generation takes place, albeit to a lesser extent than in the outer grinding zone 34. This steam can lead to a · Part of the flow direction of the grist flow in the opposite direction and can then be used to preheat the ground material or for other purposes. Another part of the steam follows the grist flow into the outer grinding zone.

The embodiment of Fig. -4 differs of those described above in that the steam separated from the outer grinding gap zone 34 via the seed channel 78 away and via a return duct 100 to the Feed zone 30 back and from there into the radial grinding gap zone 24 is introduced. To the perimeter of the revolving grinding disk 12 are expediently several channels distributed, which open near the center of the disc in a space 102 next to the throwing member 32.

'The greater part of that produced in the grinding work and by the action of the centrifugal force, steam is essentially freed of ground material by means of this channel system returned to the feed opening of the apparatus, where it is used to preheat the starting material or diverted away and used for other purposes

used without this contrary to the flow direction of the • 'Steam flowing through the millbase makes it difficult to advance to the steam generating zone.

By passing the steam it to the feed side of the grinding gap between the grinding members.

for example, unprocessed grist particles that follow with it automatically returned to the grinding zones for the purpose of renewed processing.

Claims (10)

CELL DEVELOP, INC. . . ; P.O.Box 682 September 7, 1981 Bellevue, Washington 98009 USA, Attorney's File M-5548> Process and Apparatus for Refining Fase rsjtcrf f in a Disc Refiner .. PATENT APPLICATION- 1. A method for removing steam from the grinding gap between two mutually rotating grinding members in a grinding apparatus for lump-shaped, preferably lignocellulosic starting material, this grinding gap or a radially outer section thereof having an essentially axial extension from a central inlet to an am .Externally located outlet for the ground material conveyed past the outer circumference of the grinding members, as. Characterized in that the steam counter-the. Effect of centrifugal force from the ground material with aid of in the forming the radially inner grinding surface seen circumferential Mahlglied provided »inwardly directed channels overall a wird- deposited before the ground material leaves the * MahVspalt at its outer circumferential end. "2. The method according to claim 1, characterized in this way. shows that the steam separated from the grinding stock in the gap with the steam emerging from the grinding gap Regrind is reunited. 3. The method according to claim!, Characterized in that that the separated steam from the grinding housing in a separate stream from the grinding material stream is diverted away.
25th 4. The method according to claim 1, characterized in that that the separated steam at least partially to the inlet for the grinding stock before the grinding gap is returned. · * 5. Grinder for lump-shaped, preferably lignocellulosic Output material of the disc type, its rotating meal mounted in a housing disk links on their facing surfaces, seen from the center of rotation, an inner section with a main extension in the radial direction and a outer section with main extension in have axial direction, wherein at least the outer part forms a grinding gap and grinding surfaces in the Form of channels and combs for the grinding of the grist forms under such conditions that steam is generated in the gap to carry out the method one of claims 1-4, characterized in that that the circumferential grinding disc member forming the radially inner grinding surface of the outer split ttei 1 piece (34) (12) with inwardly extending outlet channels (76) for separating this vapor from the grinding material against the effect of the centrifugal force before the grist emerges from bzq. its entry into the outer grinding gap section is provided. . . / ■ 6. grinding apparatus according to claim 5, characterized draws that the mouth of the channels (76) so relocated is that the separated steam emerges with the piece on the outer circumference of the outer grinding gap part Grist mixed (Fig. 1. and 2). 7. grinding apparatus according to claim 5, d ad u r c h characterized, that channels (76, 78) are provided for the removal of the separated steam, which • from the track for the grinding stock emerging from the grinding gap are separated (Figs. 3 and 4). 8. grinding apparatus according to claims S and 7, characterized g e k e η 'η z. e i c h η e t that the grinder housing (TO) by means of between it and the rotating grinding disk member (12) attached sealing members (82) in two chambers ν (80, 92) ", one of which (-9-2) is used to would take from the mouth of the conducting the separated vapor Channels (76) and the other (90) for receiving the finished ■ ground material and discharging it through an outlet (82) is determined in the housing (Fig. 3). ■ 9. grinding apparatus according to claims 5 and 6, d a d u r c h characterized in that the channels (76) a Continuation (78, 100) inward to the middle of the grinding disc member (12) to transfer at least part of the. separated vapor to the inlet side of the apparatus have ground material guided in front of the grinding gap (Fig. 4). 10. Grinding apparatus according to one of the preceding claims, characterized in that g. e indicates that the grinding surface (34) of the rotating grinding element (12) several outlets for the steam, which are at a distance from each other in the direction of flow of the grist or on different radii lie and become a common collecting channel. l (78) extend in the disc member. Description _ 4 _