FI104987B - Method for controlling a process for producing ground pulp - Google Patents

Method for controlling a process for producing ground pulp Download PDF

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Publication number
FI104987B
FI104987B FI991188A FI991188A FI104987B FI 104987 B FI104987 B FI 104987B FI 991188 A FI991188 A FI 991188A FI 991188 A FI991188 A FI 991188A FI 104987 B FI104987 B FI 104987B
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wood
pulp
pressure
sharpening
pressurized water
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FI991188A
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Finnish (fi)
Swedish (sv)
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FI991188A0 (en
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Tom Forsman
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Tom Forsman
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Priority to FI991188A priority Critical patent/FI104987B/en
Publication of FI991188A0 publication Critical patent/FI991188A0/en
Priority to EP00917099A priority patent/EP1196652A1/en
Priority to PCT/FI2000/000284 priority patent/WO2000073571A1/en
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    • 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
    • D21D1/002—Control devices
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/14—Disintegrating in mills
    • D21B1/18—Disintegrating in mills in magazine-type machines

Abstract

The invention relates to a method for controlling a process for producing ground pulp, in which roundwood is pressed against the periphery of a rotating grinding mill, the grinding mill is sprayed with water and the fibre suspension which has formed, i.e. the pulp, is utilized, and in which the dewatering ability or freeness CF of the pulp, and another quantity Q, which characterizes the quality of the pulp, are measured, the measured values, i.e. CFx and Qx, are compared with the desired values of the corresponding quantities, i.e. CF0 and Q0, and the wood-feeding rate Vn or the wood-feeding pressure Fn, and also the peripheral speed Vp of the grinding mill, are adjusted such that the sum (CFx-CF0)2 + (Qx-Q0)2 assumes its minimal value. When the grinding mill has reached a particular degree of bluntness, defined, for example, as a particular value of the wood- feeding pressure Fn or the wood-feeding rate Vn, or some variable which depends on these quantities, pressurized water sharpening of the grinding mill is initiated, and this pressurized water sharpening is continued until the measured quality quantity Qx differs from its desired value Q0 by a given value, i.e. the difference δQ, after which the pressurized water sharpening is discontinued. After that, the wood-feeding rate Vn or the wood-feeding pressure Fn, and also the peripheral speed Vp of the grinding mill, are adjusted such that the sum (CFx-CF0)2 + (Qx-Q0)2 assumes its minimum value.

Description

104987104987

FÖRFARANDE FÖR STYRNING AV EN PROCESS FÖR FRAMSTÄLLING AV SLIPMASSAPROCEDURE FOR CONTROLING A PROCESS FOR PREPARATION OF GRINDING

Föreliggande uppfinning bygger pä ett tidigare patenterat - förfarande för styrning av en process för framställning av slipmassa för att uppnä ett optimalt värde bäde pä massans avvattningsförmäga och en övrig egenskap hos massan, 5 företrädesvis massans rivstyrka, och där man som styrvariabler har vedmatningshastigheten eller vedmatningstrycket och slipstenens periferihastighet.The present invention is based on a previously patented process for controlling a process for producing abrasive pulp to achieve an optimal value for both the pulp's dewatering ability and other property of the pulp, preferably the pulp's tear strength, and where as the control variables the feed rate and wood feed rate are the circumferential speed of the grinding stone.

Det finska patentet FI 102975 beskriver ett förfarande för styrning av en process för framställning av slipmassa.Finnish patent FI 102975 describes a process for controlling a process for producing abrasive pulp.

10 Enligt uppfinningen mäter man massans avvattningsförmäga (freeness, CF) och en annan storhet Q, som karakteriserar massans kvalitet, företrädesvis rivstyrka (rivindex Rl) och jämför de uppmätta värdena CFX och Qx med motsvarande storheters börvärden CF0 och Q0. Vedmatningshastigheten Vn 15 eller vedmatningstrycket Fn samt slipstenens perif erihastighet Vp justeras sä, att summan (CFX - CF0)2 + (Qx - Qo)2 antar sitt minimivärde. Metoden baserar sig pä tidigare utförda försök där man funnit, att man vid • t * konstant freeness kan förbättra massans styrkeegenskaper, • ·'. *. 20 speciellt rivstyrkan, genom att sänka slipstenensAccording to the invention, the pulp dewatering capacity (freeness, CF) and another quantity Q, which characterize the pulp quality, preferably tear strength (tear index R1) are measured and compare the measured values CFX and Qx with corresponding quantities setpoints CF0 and Q0. The feed rate Vn 15 or the feed rate Fn and the peripheral velocity Vp of the grinding stone are adjusted so that the sum (CFX - CF0) 2 + (Qx - Qo) 2 assumes its minimum value. The method is based on previously performed experiments where it was found that, at constant treeness, the strength properties of the pulp can be improved. *. Especially the tear strength, by lowering the abrasive stone

JJ

* , periferihastighet. Enligt en artikel av Jan-Anders ‘ Fagerhed, "Development of wood grinding" i Paperi ja Puu - #V * Paper and Timber 72(1990):7 ökas massans rivstyrka vid ett ·.*.* · slipövertryck av 0 - 1 bar med ca 40 % dä slipstenens ··* V ’ 25 periferihastighet sänks frän 30 tili 10 m/s. Motsvarande :T: rivstyrkeökning är ca 20 % vid övertrycket 2 bar och ca. 8 ' % vid övertrycket 3-4 bar. Av samma artikel framgär :".M; ocksä, att dragstyrkan (vid ett givet freeness-värde) i · · · nägon män kan päverkas av periferi-hastigheten hos **.·,·/' 30 slipstenen även om effekten ej är lika tydlig som för rivstyrkan. Vid slipning under atmosfärstryck uppnär man ί''·;ί dock en dragstyrkeökning av ca 35 % dä periferihastigheten • · « sänks frän 30 tili 10 m/s.*, peripheral speed. According to an article by Jan-Anders' Fagerhed, "Development of wood grinding" in Paperi ja Puu - #V * Paper and Timber 72 (1990): 7 the pulp tear strength is increased at a ·. *. * · Abrasive overpressure of 0 - 1 bar with about 40% of the grinding stone's ·· * V '25 peripheral speed is lowered from 30 to 10 m / s. Corresponding: T: tear strength increase is about 20% at overpressure 2 bar and approx. 8 '% at overpressure 3-4 bar. From the same article it is stated: "M; also, that the tensile strength (at a given freeness value) in · any · men can be affected by the peripheral velocity of the **. ·, · / '30 grinding stone, although the effect is not equal When grinding under atmospheric pressure, however, a tensile strength increase of about 35% is achieved when the peripheral velocity is reduced from 30 to 10 m / s.

2 104987 I ovannämnda patentskrift sags ingenting om slipstenens skärpning.In the above-mentioned patent, nothing is said about the sharpening of the grindstone.

Dä en slipsten för tillverking av slipmassa blir ovass mäste man tillgripa skärpning. Traditionellt har slipstenar 5 skärpts pä mekanisk väg. Denna skärpningsmetod är dock förknippad med en del olägenheter. För det första miste produktionen stoppas för den tid skärpningen pigär. För det andra blir stenen lätt alltför vass, vilket i sin tur leder att massans freeness stiger för högt och massakvaliteten 10 blir undermälig om man inte samtidigt sänker vedmatningshastigheten eller -trycket (dvs. sänker produktionen). Detta beror pä att en mycket vass stenyta inte defibrerad veden p& önskat sätt utan snarare skär lös vedstycken. För att motverka denna effekt miste 15 belastningen sänkas.When a grinding stone for the production of abrasive pulp becomes oily, one must resort to sharpening. Traditionally, grinding stones 5 have been sharpened by mechanical means. However, this sharpening method is associated with some drawbacks. First of all, the production loss stopped for that time the sharpening of the pig. Secondly, the stone becomes slightly too sharp, which in turn causes the pulp freeness to rise too high and the pulp quality 10 becomes inferior if one does not simultaneously reduce the wood feed rate or pressure (i.e., lowers production). This is because a very sharp stone surface does not defibrate the wood in the desired manner but rather cuts loose pieces of wood. In order to counteract this effect, the load was lost.

Tryckvattenskärpning av slipstenar för framställning av slipmassa har föreslagits i artiklarna S Blomqvist et ai., "Water Jet - New Tecnique for Pulpstone Surface Control", 1994 Pulping Conference, TAPPI Proceedings, s. 601-610, och 20 A Puurunen et al., "First Mill Scale Experiences of the Water Jet Pulpstone Conditioning System at UPM-Kymmene t i ,v. Voikkaa and Rauma Paper Mill", 1997 Pulping Conference, TAPPI Proceedings, s. 317-322. Det konstaterades, att • · <t<<; tryckvatten med ett tryck i omridet 500-2500 bar lämpar sig • ...^ 25 väl för skärpning av slipstenen under drift. Genom att skärpan hos stenen kan regleras mycket noggrant med denna • · · *' ' skärpningsmetod kan man hilla högre produktion och jämnarePressurized water sharpening of grindstones for the production of abrasive pulp has been proposed in Articles S Blomqvist et al., "Water Jet - New Technique for Pulpstone Surface Control", 1994 Pulping Conference, TAPPI Proceedings, pp. 601-610, and 20 A Puurunen et al., "First Mill Scale Experiences of the Water Jet Pulpstone Conditioning System at UPM-Kymmene ti, v. Voikkaa and Rauma Paper Mill," 1997 Pulping Conference, TAPPI Proceedings, pp. 317-322. It was found that • · <t <<; pressurized water at a pressure in the range of 500-2500 bar is well suited for sharpening the grindstone during operation. Because the sharpness of the stone can be controlled very carefully with this • · · * '' sharpening method, one can pay tribute to higher production and more evenly.

awattnings- och styrkeegenskaper för massan. Artikeln JHJdewatering and strength properties for the pulp. The article JHJ

··# ·...· Lehto et ai., "New Thinking in Groundwood Process Control"·· # · ... · Lehto et al., "New Thinking in Groundwood Process Control"

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ϊ,,/ 30 (i tryck) föreslar automatisering av skärpningen av ;V« slipstenen i en slipmasseprocess. Som mitt pä slipstenens f * kondition lanserade artikelförfattarna begreppet ! i "saturation degree" eller mättningsgraden, definierad som : '· den relativa tid som hydraulventilerna är öppna mera än 90 < · * 35 %.ϊ ,, / 30 (in print) proposes automation of the sharpening of; V «grindstone in a grinding process. Like my grinding stone's fitness, the article writers launched the concept! in the "saturation degree" or degree of saturation, defined as: 'the relative time that the hydraulic valves are open more than 90 <· * 35%.

3 1049873 104987

Ingen av de ovannämnda artiklarna antyder nägot om, att man kunde koppia slipstenens skärpning tili 2-variabelstyrningen av slipmasseprocessen enligt det finska patentet FI 102975, där massans freeness CF och 5 kvalitetsegenskap Q används som mätvariabler och vedmatningshastigheten (eller vedmatningstrycket) och stenens periferihastighet används som styrvariabler. Avsikten med föreliggande uppfinning är att kombinera metoden enligt FI 102975 med automatiserad 10 tryckvattenskärpning av slipstenen, varvid man fär en 3-variabelstyrning, där vattentrycket är den tredje styrvariablen.None of the above-mentioned articles suggests that the sharpening of the grindstone could be coupled to the 2-variable control of the grinding process according to the Finnish patent FI 102975, where the pulp freeness CF and quality property Q are used as measurement variables and the feed rate (or wood feed pressure) and the stone rate are used. control variables. The object of the present invention is to combine the method according to FI 102975 with automated pressure water sharpening of the grinding stone, whereby a 3-variable control is obtained, where the water pressure is the third control variable.

Uppfinningens kännetecken framgär av patentkravet 1.The features of the invention are set forth in claim 1.

Förfarandet kan användas vid säväl vanlig stenslipning utan 15 övertryck (sk. stone groundwood eller SGW-massa) som vid sk. tryckslipning (pressure groundwood eller PGW).The method can be used in both ordinary stone grinding without overpressure (so-called stone groundwood or SGW pulp) as in so-called. pressure groundwood (PGW).

Massans CF-tal och rivindex hälls pä önskad nivä och man minimerar summan av avvikelserna « · III • « «The CF number and the tear index of the pulp are kept at the desired level and the sum of the deviations «· III •« «is minimized.

ViV; (CFX-CF0)2 + (RIX-RI0)2ViV; (CFX-CF0) 2 + (RIX-RI0) 2

» I»I

« · · * ·.·.·*.: 20 där CF0 = börvärdet för freeness, CFX = det uppmätta # · · freeness-värdet, RI0 = börvärdet för rivindex och RIX = det *111 uppmätta värdet för rivindex.«· · * ·. ·. · * .: 20 where CF0 = the freeness setpoint, CFX = the measured # · · freeness value, RI0 = the tear index setpoint and RIX = the * 111 measured tear index value.

*.· * · • · · « · · • · ·*.

Sambandet mellan slipstenens skärpa och massans egenskaper i · · * är tidigare publicerat (se t.ex. Georg v. Alitan, ’V** 25 "Valmistusolojen vaikutus mekaanisen massan ominaisuuksiin" i läroboken "Puukemia", Waldemar Jensen, Helsingfors 1967 .The relationship between the sharpness of the grindstone and the properties of the pulp in · · * has been previously published (see, for example, Georg v. Alitan, 'V ** 25 "Valmistusolojen vaikutus mekaanisen massan ominaisuuksiin" in the textbook "Puukemia", Waldemar Jensen, Helsinki 1967.

< 1 « « I I 1 ·<1 «« I I 1 ·

• * | I• * | IN

I FI 102975 presenterades mätdata som publiserats av Jan-In FI 102975, measurement data published by Jan-

I · · II · · I

'/·>' Anders Fagerhed (Development of wood grinding. Part 3'/ ·>' Anders Fagerhed (Development of wood grinding. Part 3

Effects of casing pressure and pulpstone speed, Paperi-30 Puu - Paper and Timber 72 (1990):7, 680 - 686 och som 4 104987 kompletterats med hittills opublicerat material. Pä basen av dessa mätdata kan man medelst regressionsanalys bestämma sambandet mellan storheter som beskriver massans egenskaper (freeness, rivindex) och processens driftbetingelser.Effects of casing pressure and pulpstone speed, Paperi-30 Puu - Paper and Timber 72 (1990): 7, 680 - 686 and supplemented with hitherto unpublished material. On the basis of this measurement data it is possible to determine, by means of regression analysis, the relationship between quantities describing the pulp's properties (freeness, tear index) and the operating conditions of the process.

5 Slipprosessen enligt denna uppfinning päverkas i princip av tre styrvariabler, nämligen vedmatningshastigheten (eller kraften), slipstenens periferihastighet och vattentrycket. Matningshastigheten kan hälla massans CF-tal pä önskad nivä och stenens periferihastighet, en annan variabel, pä önskad 10 nivä. Vid en viss kondition av slipstenens yta, dvs. dä en viss grad av trubbighet uppnätts, startas tryckvattenskärpningen. Sedan fortsätter man med denna tryckvattenskärpning ända tills en uppmätt kvalitetsstorhet Qx, företrädes rivindexet Rl, avviker frän sitt börvärde Q0 15 med ett givet värde, skillnaden AQ, varefter man avbryter tryckvattenskärpningen och justerar vedmatningshastigheten Vn eller vedmatningstrycket Fn samt slipstenens periferihastighet Vp sä, att summan (CFX - CF0)2 + (Qx - Q0)2 antar sitt minimivärde.The grinding process of this invention is in principle influenced by three control variables, namely, the feed rate (or force), the peripheral speed of the grindstone and the water pressure. The feed rate can keep the CF number of the pulp at the desired level and the peripheral speed of the stone, another variable, at the desired level. At a certain condition of the surface of the grinding stone, ie. when a certain degree of blurring is achieved, the pressure water sharpening is started. Then, this pressure water sharpening is continued until a measured quality quantity Qx, preferably the tear index R1, deviates from its set value Q0 by a given value, the difference AQ, after which the pressure water sharpening is adjusted and the feed rate Vn or the feed rate pressure Fn (CFX - CF0) 2 + (Qx - Q0) 2 adopts its minimum value.

2020

Graden av trubbighet för slipstenen kan definieras pä flera sätt, t.ex som ett visst värde för vedmatningstrycket Fn < < eller vedmatningshastigheten Vn eller nägon variabel beroende av dessa. Ett lämpligt mätt pä trubbigheten är 25 t.ex. den relativa tiden som hydraulventilen (eller * · · ...S,. -ventilerna) är öppen 90 % eller mera.The degree of blurring of the grindstone can be defined in several ways, for example as a certain value for the wood feed pressure Fn <<or the wood feed rate Vn or any variable depending on them. A suitable measure of the bluntness is e.g. the relative time that the hydraulic valve (or * · · ... S,. valves) is open 90% or more.

• · * · ' * • · « • · · • · ·*· • # # · *,!:* ’ Företrädesvis är den uppfölja kvalitetsstorheten Q är ett • * * *·* mätt pä massans rivstyrka säsom t.ex. rivindex Rl. I detta • « · ·.· : fall avbryts tryckvattenskärpningen dä det uppmätta '*·?' 30 rivindexet RIX understiger sitt börvärde RI0 med en *; ?t definierad skillnad ARI. Valet av RI0 och ARI bestämmer t - t ·;<>', säledes den önskade skärpan för slipstenen.Preferably, the follow-on quality quantity Q is a • * * * · * measured by the tear strength of the pulp such as e.g. tear index Rl. In this case, the pressure water sharpening is interrupted when the measured '* ·?' The tear index RIX is less than its set value R10 with a *; Not defined difference ARI. The choice of RI0 and ARI determines t - t ·; <> ', thus the desired sharpness for the grindstone.

ζ « , c f t I f f' /, Även om det är tänkbart att utföra tryckvattenskärpningen J « med ett konstant vattentryck i omrädet 500 - 2500 bar, är <11 • f . « « • · · 5 104987 det fördelaktigt att successivt höja vattnets tryck under skärpningens gäng. Begynnelsetrycket kan vara ca. 500-1000 bar och det slutliga trycket ca. 2500 bar.ζ «, c f t I f f '/, Although it is conceivable to perform the pressurized water sharpening J« with a constant water pressure in the range 500 - 2500 bar, <11 • f. It is advantageous to gradually increase the pressure of the water during the tightening thread. The initial pressure may be approx. 500-1000 bar and the final pressure approx. 2500 bar.

Under tryckvattenskärpningen hälls vedmatningshastigheten 5 Vn, vedmatningstrycket Fn samt slipstenens periferihastighet Vp Stminstone i det närmaste konstant.During the pressurized water tightening, the wood feed rate 5 Vn, the wood feed pressure Fn and the peripheral speed of the grindstone Vp Stminstone are poured to the nearest constant.

Prosessen kan därmed regleras med ett multivariabelt förfarande med tre insignaler och tvä utsignaler.The process can thus be controlled by a multivariable method with three inputs and two outputs.

Regleringen kan ske med hjälp av en multivariabel 10 regleralgoritm som beskrivits i FI 102975.The control can be done using a multivariable control algorithm described in FI 102975.

• « *> · * t · · • · • · • « t · • i <« l « « · « t • · • ·. ' A.!• «*> · * t · · • · • · •« t · • i <«l« «·« t • · • ·. 'A.!

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Claims (6)

1. Menetelmä hiokkeen valmistusprosessin ohjaamiseksi, jolloin pyöreä puu painetaan pyörivän hiomakiven kehää vasten, hiomakiveen ruiskutetaan vettä ja syntynyt kuitususpensio, massa, otetaan talteen, ja jolloin mitataan 5 massan vedenluovutuskyky eli freeness CF ja toinen massan laatua kuvaava suure Q, verrataan mitattuja arvoja CFX ja Q* vastaavien suureiden oletusarvoihin CF0 ja Q0, ja säädetään puun syöttönopeus Vn tai puun syöttöpaine Fn sekä hiomakiven kehänopeus Vp niin, että summa (CFX - CF0)2 + (Qx - Q0)2 10 minimoituu, käynnistetään hiomakiven teroitus paineveden avulla kun hiomakivi on saavuttanut tietyn tylsistymisasteen, määriteltynä esimerkiksi puun syöttö-paineen Fn tai puun syöttönopeuden Vn tai jonkin näistä riippuvan muuttujan avulla, tunnettu siitä, että jatketaan 15 tätä painevesiteroitusta kunnes mitattu laatusuure Qx poikkeaa oletusarvostaan Q0 määrätyllä arvolla, erolla AQ, jonka jälkeen keskeytetään painevesiteroitus ja säädetään puun syöttönopeus Vn tai puun syöttöpaine Fn sekä hiomakiven kehänopeus Vp niin, että summa (CFX - CF0)2 + (Qx - Q0)2 : 20 minimoituu. « I « I < I « III· - I I r1. A method for controlling the pulping process, wherein the circular wood is pressed against the periphery of a rotating grinding stone, water is injected into the grinding stone and the resulting fiber suspension, pulp, is recovered and the 5 pulp water yield or CF is measured. Q * to the default values of CF0 and Q0 for the respective quantities, and adjusting the wood feed rate Vn or wood feed pressure Fn and the grindstone peripheral speed Vp to minimize the sum of (CFX - CF0) 2 + (Qx - Q0) 2 10 by triggering sandstone sharpening with pressurized water has reached a certain degree of dullness, as determined, for example, by the wood feed pressure Fn or wood feed rate Vn or one of the variables dependent thereon, characterized by continuing this pressure water sharpening until the measured quality Qx deviates from its default value Q0, adjust the wood feed rate Vn or wood feed pressure Fn and the grindstone peripheral speed Vp so that the sum of (CFX - CF0) 2 + (Qx - Q0) 2: 20 is minimized. «I« I <I «III · - I I r · ‘2. Patenttivaatimuksen 1 mukainen menetelmä, tunnettu < Il «· '2. The method according to claim 1, characterized by <Il « 1 I I ( I « 1' « « I « I « * t « 9% 9 • · * • # · 999*· « ·*«· • 99 9*9 · · 9 · »· 9 9 9 • ·«· • · · *· I I • · · 9 · 9 « « _ ···· · * · ·* • I 9 9 9 9 9 · · 9 f r I» c i' c c t t , , r i f f c t' t f i 8 1049871 II {I «1 '« «I« I «* t« 9% 9 • · * • # · 999 * · «· *« · • 99 9 * 9 · · 9 · »· 9 9 9 • ·« · • · · * · II • · · 9 · 9 «« _ ···· · * · · * • I 9 9 9 9 9 · · 9 fr I »ci 'cctt,, riffct' tfi 8 104987 3. Patenttivaatimuksen 1 tai 2 mukainen menetelmä, tunnettu ;*·*^ siitä, että paineveden paine nostetaan painevesiteroituksen *.* * aikana. • · • · • · · · · • ·» • #« III..: 4. Patenttivaatimuksen 1, 2 tai 3 mukainen menetelmä, • ·· · tunnettu siitä, että puun syöttönopeus Vn, puun syöttöpaine I f * 1Method according to claim 1 or 2, characterized in that the pressure of the pressurized water is increased during the pressurization of the pressurized water. The process according to claim 1, 2 or 3, characterized in that the wood feed rate Vn, the wood feed pressure I f * 1 30 Fn sekä hiomakiven kehänopeus Vp pidetään likimain vakioina painevesiteroituksen aikana. « < ( I30 Fn and the circumferential velocity Vp of the grindstone are kept approximately constant during pressure water sharpening. «<(I 4. I V..;.,: siitä, että suure Q on massan repäisylujuutta kuvaava u * suure, kuten esimerkiksi repäisyindeksi Rl. • m · ···«·· ...4. I V ..;.,: That Q is a measure of the tear strength u * of the pulp, such as the tear index R1. • m · ··· «·· ... 5. Jonkin edellisen patenttivaatimuksen mukainen menetelmä, 9 104987 tunnettu siitä, että painevesiteroitusta aloitetaan sellaisessa puun syöttöpaineessa, joissa hydrauliventtiili tai hydrauliventtiilit ovat tietyn ajan auki ainakin 90 % ja että painevesiteroitus keskeytetään kun mitattu 5 repäisyindeksi Rl, alittaa oletusarvonsa RI0 määrätyllä erolla ARI.A method according to any one of the preceding claims, characterized in that the pressurized water sharpening is initiated at a wood feed pressure in which the hydraulic valve or valves are open for at least 90% for a certain time and that the pressurized water sharpening is interrupted when measured by tear index R1. 6. Jonkin edellisen patenttivaatimuksen mukainen menetelmä, tunnettu siitä, että ohjaus suoritetaan monimuuttuvan säätöalgoritmin avulla. • · • 4 · • « I • , I | f i ' i · Λ i \ i t t · « · I • l 'i!!' • · · • · % ·1»·· • · « • »» ·· 1 · • · «· · • · « V· 1 • \ · • · · • · · • » 1 ··· * I · *· · • · • · #«· • · · • I I « « r, f • · 4 * « 1 «. 1 « 1 1 1 • 1 « « « \ • |l' • i » I » 1 · I · « · ·Method according to one of the preceding claims, characterized in that the control is performed by means of a variable control algorithm. • · • 4 · • «I •, I | f i 'i · Λ i \ i t t · «· I • l' i !! ' • · · • ·% · 1 »·· • ·« • »» ·· 1 · • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · * · · • • • • # «· • · II« «r, f • · 4 *« 1 «. 1 «1 1 1 • 1« «« \ • | l '• i »I» 1 · I · «· ·
FI991188A 1999-05-26 1999-05-26 Method for controlling a process for producing ground pulp FI104987B (en)

Priority Applications (3)

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FI991188A FI104987B (en) 1999-05-26 1999-05-26 Method for controlling a process for producing ground pulp
EP00917099A EP1196652A1 (en) 1999-05-26 2000-04-03 A method for the control of a ground wood pulping process
PCT/FI2000/000284 WO2000073571A1 (en) 1999-05-26 2000-04-03 A method for the control of a ground wood pulping process

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FI991188 1999-05-26
FI991188A FI104987B (en) 1999-05-26 1999-05-26 Method for controlling a process for producing ground pulp

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FI122784B (en) 2002-04-19 2012-06-29 Metso Paper Inc Arrangement for treatment of a grinding stone surface in a wooden grind

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FI88938C (en) * 1991-08-09 1993-07-26 Tampella Papertech Oy Method and apparatus for sharpening the surface of the wood grinder's lipstick
FI102975B1 (en) * 1996-06-25 1999-03-31 Tom Forsman A method for controlling the process of making a groundwood

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EP1196652A1 (en) 2002-04-17
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