WO1989007687A1 - Process for controlling a pulp grinder - Google Patents

Process for controlling a pulp grinder Download PDF

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Publication number
WO1989007687A1
WO1989007687A1 PCT/EP1989/000143 EP8900143W WO8907687A1 WO 1989007687 A1 WO1989007687 A1 WO 1989007687A1 EP 8900143 W EP8900143 W EP 8900143W WO 8907687 A1 WO8907687 A1 WO 8907687A1
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WO
WIPO (PCT)
Prior art keywords
temperature
power consumption
wood
spray
trough
Prior art date
Application number
PCT/EP1989/000143
Other languages
German (de)
French (fr)
Inventor
Wolfgang Barnscheidt
Frank Jansen
Original Assignee
Feldmühle Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Feldmühle Aktiengesellschaft filed Critical Feldmühle Aktiengesellschaft
Publication of WO1989007687A1 publication Critical patent/WO1989007687A1/en
Priority to NO894118A priority Critical patent/NO894118D0/en

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Classifications

    • 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
    • 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

Definitions

  • the invention relates to a method for regulating a wood grinder, in the wooden stick by means of a. grinding stone dipped in the trough material with addition of spray and / or trough dilution water to a wood pulp suspension, the temperature of the spray and / or trough dilution water being controlled so that the temperature increase in the grinding zone is kept below the evaporation point.
  • a method for controlling a wood grinder in which the trough temperature and / or the shaft water temperature is kept below an upper limit value, ie that the trough temperature is influenced by varying the temperature of the trough dilution water or the grinder spray water.
  • the proposed solution according to DE-OS 33 25 049 starts at a relatively late point in time, namely when already The fibers have been damaged by the grinding process at too high a temperature.
  • the invention was therefore based on the object of developing a method which makes it possible to recognize the risk of an increase in the grinding temperature in the grinding zone as early as possible and to avoid the formation of vapor bubbles in the grinding zone by means of suitable measures. In a generic method, this is achieved by the combination of features given in the characterizing part of claim 1.
  • V is the wood feed and the power of the feed motor.
  • the computer can thus automatically trigger a signal that lowers the spray water temperature.
  • the working point is below the drawn line, i.e. below the ⁇ curve, there is enough cold spray water available, but the grinding temperature is not optimal, ie too far below the boiling point. In this case, it is ensured that the spray water temperature is raised to drive the grinder in the optimal range again.
  • the grinding Since the change in the working point of the grinder can be detected immediately when it occurs, that is, long before a change in the temperature in the trough of the grinder becomes noticeable, the grinding remains constant, i. H. There is no dry friction between stone and wood with the dreaded burning of the material and the optimal grinding temperature is also maintained.
  • a preferred embodiment of the invention provides that the fixed value ⁇ , which is present as a curve, includes a tolerance range, this tolerance range being expediently selectable. This ensures that short-term fluctuations in the nature of the wood, which balance themselves out within a very short period of time, do not lead to a control process, but only if the tolerance limit is exceeded upwards or downwards.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
  • Debarking, Splitting, And Disintegration Of Timber (AREA)
  • Manufacture Of Wood Veneers (AREA)

Abstract

In a process for controlling a pulp grinder, the temperature of the spray-diluting water is controlled so that the temperature increase in the grinding zone is below the vaporization point. For this purpose, the specific power consumption of the pulp grinder motor and the advance of the wood feeding aggregate as well as the power consumption of the drive motor of said aggregate are reduced and the relationship between them derived. The result so obtained is compared with a discretionary constant. If the constant is exceeded, the temperature of the spray water is reduced. If the result falls below the constant, the temperature of the spray water is increased. The constant includes a given tolerance range of discretionary magnitude.

Description

Verfahren zur Regelung eines Holzschleifers Process for regulating a wood grinder
Die Erfindung betrifft ein Verfahren zur Regelung eines Holzschleifers, bei dem Holzknüppel mittels eines ggf . in den Trogstoff tauchenden Schleifersteines unter Zugabe von Spritz- und/oder Trogverdünnungswasser zu einer HolzschliffSuspension verschliffen werden, wobei die Temperatur des Spritz- und/oder Trogverdünnungswassers so gesteuert wird, daß die Temperaturerhöhung in der Schleifzone unterhalb des Verdampfungspunktes gehalten wird.The invention relates to a method for regulating a wood grinder, in the wooden stick by means of a. grinding stone dipped in the trough material with addition of spray and / or trough dilution water to a wood pulp suspension, the temperature of the spray and / or trough dilution water being controlled so that the temperature increase in the grinding zone is kept below the evaporation point.
Aus der DE-OS 33 25 049 ist ein Verfahren zur Regelung eines Holzschleifers bekannt, bei dem die Trogstofftemperatur und/oder die Schachtwassertemperatur unterhalb eines oberen Grenzwertes gehalten wird, d. h. , daß durch Variieren der Temperatur des Trogverdünnungswassers oder des Schleiferspritzwassers die Trogstofftemperatur beeinflußt wird. Durch die vorgenannten Maßnahmen hat man versucht, die Qualität des Schliffes von Pressen¬ oder auch von Stetigschleifern weiter zu verbessern, da seit langem bekannt ist, daß die Temperatur im Bereich der Schleifzone einen besonderen Einfluß auf die Schliffqualität hat. Es war ferner bekannt, zur Erweichung des Lignins und damit zur einfacheren Ablösung der Faser vom Holz die Temperatur möglichst hoch zu halten, um einerseits das Herauslösen der Fasern aus dem Holzverband zu erleichtern, andererseits den Energieaufwand zu verringern. Diese sogenannten Heißschliffverfahren erbrachten zwar eine gewisse Verbesserung der Holzschliffqualität, sie war jedoch nicht einheitlich, sondern unterlag größeren Schwankungen, die sich trotz zahlreicher Bemühungen nicht vermeiden ließen. Mit der DE-OS 33 25 049 wurde der Versuch unternommen, die Trogstofftemperatur konstant zu halten und dadurch die Qualität des Schliffes zu verbessern. Da aber rein von der Überlegung her die Trogstofftemperatur erst dann sich erhöhen kann, wenn bereits in der Schleifzone eine Erhöhung der Temperatur erfolgt ist, setzt der Lösungsvorschlag gemäß der DE-OS 33 25 049 an einem relativ späten Zeitpunkt an, nämlich dann, wenn bereits eine Schädigung der Fasern durch den Schleif rozeß bei zu hoher Temperatur erfolgt ist.From DE-OS 33 25 049 a method for controlling a wood grinder is known in which the trough temperature and / or the shaft water temperature is kept below an upper limit value, ie that the trough temperature is influenced by varying the temperature of the trough dilution water or the grinder spray water. Through the aforementioned measures, attempts have been made to further improve the quality of the grinding of presses or also of continuous grinders, since it has long been known that the temperature in the area of the grinding zone has a particular influence on the quality of the grinding. It was also known to Softening the lignin and thus for easier detachment of the fiber from the wood, keeping the temperature as high as possible, on the one hand to facilitate the removal of the fibers from the wood structure, and on the other hand to reduce the energy consumption. These so-called hot sanding processes brought about a certain improvement in the quality of the sanded wood, but it was not uniform, but was subject to greater fluctuations which, despite numerous efforts, could not be avoided. With DE-OS 33 25 049 an attempt was made to keep the trough temperature constant and thereby to improve the quality of the cut. However, since the trough temperature can only increase from the point of view only if the temperature has already increased in the grinding zone, the proposed solution according to DE-OS 33 25 049 starts at a relatively late point in time, namely when already The fibers have been damaged by the grinding process at too high a temperature.
Der Erfindung lag damit die Aufgabe zugrunde, ein Verfahren zu entwickeln, das es ermöglicht, die Gefahr des Anstiegs der Schleiftemperatur in der Schleifzone möglichst frühzeitig zu erkennen und die Bildung von Dampfblasen in der Schleifzone durch geeignete Maßnahmen zu vermeiden. Bei einem gattungsgemäßen Verfahren wird das durch die im kennzeichnenden Teil des Anspruchs 1 gegebene Merkmalskombination erreicht.The invention was therefore based on the object of developing a method which makes it possible to recognize the risk of an increase in the grinding temperature in the grinding zone as early as possible and to avoid the formation of vapor bubbles in the grinding zone by means of suitable measures. In a generic method, this is achieved by the combination of features given in the characterizing part of claim 1.
Ausgehend von der Überlegung, daß die Erhitzung des Stoffes in jedem Fall in der Schleifzone auftritt und daß das Auftreten von Dampfblasen durch die Zufuhr von kälterem Spritzwasser zum Stein vermieden werden kann, ergab sich die Frage nach frühzeitig erkennbaren Merkmalen.Based on the consideration that the heating of the material always occurs in the grinding zone and that the occurrence of steam bubbles by the supply of colder splashing water to the stone can be avoided, the question arose early on.
Aus dem Vortrag "Thermogrinding" von Meinecke, veröffentlicht in "Proceedings International Mechanical Pulping Conference 1985", Seite 136 ff., geht hervor, daß es bis zum heutigen Tag nicht möglich ist, die Temperatur im Schleifbereich direkt zu messen. Man geht daher nach wie vor davon aus, daß man die Temperatur des Trogstoffes im Schleifertrog mißt, um Anhaltswerte für die Temperatur in der Schleifzone zu erhalten. Dem Vortrag ist weiter zu entnehmen, daß die kombinierte Aufzeichnung der spezifischen Energie - des Schleifersteines - und der Temperatur des Trogstoffes eine Steuerung ermöglicht. Diese Steuerung, die mit der in der DE-OS 33 25 049 beschriebenen identisch ist, führt aber nach wie vor zu einer ungleichen Stofferzeugung, d. h. zu einem Pendeln des Schleifers. Da aufgrund der vorhandenen großen Stoffmassen im Trog des Schleifers eine meßbare Erwärmung des Trogstoffes wesentlich später einsetzt als die überhitzung in der Schleifzone und damit die Verschlechterung des erhaltenen Schliffes, mußte ein anderer Weg gegangen werden.The presentation "Thermogrinding" by Meinecke, published in "Proceedings International Mechanical Pulping Conference 1985", page 136 ff., Shows that to this day it is not possible to measure the temperature in the grinding area directly. It is therefore still assumed that the temperature of the trough material in the grinding trough is measured in order to obtain reference values for the temperature in the grinding zone. The lecture also shows that the combined recording of the specific energy - the grinder stone - and the temperature of the trough material enables control. This control, which is identical to that described in DE-OS 33 25 049, still leads to an uneven production of substances, i. H. to a swaying of the grinder. Since due to the large masses of material present in the grinder trough, measurable heating of the trough material commences much later than overheating in the grinding zone and thus the deterioration of the grind obtained, a different approach had to be taken.
Überlegungen führten zu der Erkenntnis, daß die Temperaturerhöhung auf eine Veränderung des Reibungswiderstandes zwischen Stein und Holz zurückzuführen sind. Der Reibungskoeffizient ist eine Funktion der Steinrauhigkeit. Mit größerer Steinrauhigkeit wird der Reibungskoe fizient größer. Daraus folgt, daß sich eine empirisch zu bestimmende Kurve erstellen läßt - Reibungskoeffizient in Abhängigkeit von der Steinrauhigkeit -. Diese Kurve kann man aufbauend auf den Analysen von Steenberg, "Analysis of Grinding Process Variables", veröffentlicht in "Svensk Papperstidning" , Nr. 11 vom 15. Juni 1957, Seite 409 ff., definieren alsConsiderations led to the realization that the temperature increase is due to a change in the frictional resistance between stone and wood. The coefficient of friction is a function of stone roughness. The friction coefficient increases with greater stone roughness. From this it follows that an empirically determined one Curve can be created - coefficient of friction depending on the stone roughness -. This curve can be defined based on the analyzes by Steenberg, "Analysis of Grinding Process Variables", published in "Svensk Papperstidning", No. 11 of June 15, 1957, page 409 ff
L x V μ _L x V μ _
Lv worin μ der Reibungskoeffizient, L v where μ is the coefficient of friction,
L die Leistung des Schleifmotors,L the power of the grinding motor,
V der Holzvorschub und die Leistung des Vσrschubmotors ist.V is the wood feed and the power of the feed motor.
Alle drei Größen zur Ermittlung des Reibungskoeffizienten können ohne Schwierigkeiten gemessen und ihre Werte kontinuierlich in einen Rechner eingegeben werden, der den jeweils auftretenden Reibungskoeffizienten μ berechnet. Erhöht sich μ, liegt also der Arbeitspunkt des Schleifers oberhalb der auf einem Oszillographen darstellbaren μ-Linie, so muß eineAll three variables for determining the coefficient of friction can be measured without difficulty and their values can be continuously input into a computer which calculates the coefficient of friction μ that occurs in each case. If μ increases, ie if the grinder's working point lies above the μ line that can be displayed on an oscillograph, one must
Wasserverdampfung stattgefunden haben und damit die Schleiffläche trockene Streifen aufweisen. Der Rechner kann damit automatisch ein Signal auslösen, das zur Herabsetzung der Spritzwassertemperatur führt. Liegt andererseits der Arbeitspunkt unterhalb der gezeichneten Linie, also unterhalb der μ-Kurve, so ist zwar genügend kaltes Spritzwasser vorhanden, die Schleiftemperatur aber nicht optimal, d. h. zu weit unter dem Siedepunkt. In diesem Fall wird dafür gesorgt, daß die Spritzwassertemperatur angehoben wird, um den Schleifer wieder im optimalen Bereich zu fahren.Evaporation of water has taken place and thus the grinding surface has dry streaks. The computer can thus automatically trigger a signal that lowers the spray water temperature. On the other hand, if the working point is below the drawn line, i.e. below the μ curve, there is enough cold spray water available, but the grinding temperature is not optimal, ie too far below the boiling point. In this case, it is ensured that the spray water temperature is raised to drive the grinder in the optimal range again.
Da die Veränderung des Arbeitspunktes des Schleifers unmittelbar bei ihrem Auftreten erfaßt werden kann, also lange, bevor sich eine Änderung der Temperatur im Trog des Schleifers bemerkbar macht, bleibt der Schliff konstant, d. h. es tritt keine trockene Reibung zwischen Stein und Holz mit dem gefürchteten Verbrennen des Stoffes auf und es wird auch die optimale Schleiftemperatur eingehalten.Since the change in the working point of the grinder can be detected immediately when it occurs, that is, long before a change in the temperature in the trough of the grinder becomes noticeable, the grinding remains constant, i. H. There is no dry friction between stone and wood with the dreaded burning of the material and the optimal grinding temperature is also maintained.
Um jegliches Pendeln des Schleifers auszuschalten, sieht eine bevorzugte Ausgestaltung der Erfindung vor, daß der Festwert μ, der als Kurve vorliegt, einen Toleranzbereich einschließt, wobei dieser Toleranzbereich zweckmäßig wählbar ist. Dadurch ist sichergestellt, daß es nicht durch kurzfristige Schwankungen in der Holzbeschaffenheit, die sich von allein innerhalb kürzester Frist ausgleichen, zu einem Regelvorgang kommt, sondern nur dann, wenn die Toleranzgrenze nach oben oder unten überschritten wird. In order to eliminate any swaying of the grinder, a preferred embodiment of the invention provides that the fixed value μ, which is present as a curve, includes a tolerance range, this tolerance range being expediently selectable. This ensures that short-term fluctuations in the nature of the wood, which balance themselves out within a very short period of time, do not lead to a control process, but only if the tolerance limit is exceeded upwards or downwards.

Claims

Patentansprüche Claims
1. Verfahren zur Regelung eines Holzschleifers, bei dem Holzknüppel mittels eines ggf. in den Trσgstoff tauchenden Schleifersteines unter Zugabe von Spritz- und/oder Trogverdünnungswasser zu einer Holzschliffsuspnsion verschliffen werden, wobei die Temperatur des Spritz- und/oder Trogverdünnungswassers so gesteuert wird, daß die Temperaturerhöhung in der Schleifzone unterhalb des Verdampfungspunktes liegt, gekennzeichnet durch die Kombination folgender Merkmale: vom Antriebsmotor des Holzschleifers wird die momentane Leistungsaufnahme abgefragt und auf die spezifische Leistungsaufnahme umgerechnet, vom Antriebsmotor des Holzvorschubaggregates wird die momentane Leistungsaufnahme sowie der Vorschub abgefragt, die spezifische Leistungsaufnahme des Holzschleifermotors und der Vorschub wird in Relation zur Leistungsaufnahme des Antriebsmotors des Holzvorschubaggregates gesetzt, das daraus erhaltene Resultat wird mit einem wählbaren Festwert verglichen, wobei bei Abweichung des Resultates vom Festwert nach oben die Temperatur des Spritzwassers abgesenkt, bei Abweichung nach unten die Temperatur des Spritzwassers erhöht wird.1. Method for regulating a wood grinder, in which the wooden billet is ground to a wood pulp suspension by means of a grinding stone which may possibly be immersed in the carrier material, with the addition of spray and / or trough dilution water, the temperature of the spray and / or trough dilution water being controlled in such a way that The temperature increase in the grinding zone is below the evaporation point, characterized by the combination of the following features: the drive motor of the wood grinder queries the current power consumption and converts it to the specific power consumption, the drive motor of the wood feed unit queries the current power consumption and the feed rate, the specific power consumption of the Wood grinder motor and the feed is set in relation to the power consumption of the drive motor of the wood feed unit, the result obtained is compared with a selectable fixed value, whereby at If the result deviates from the fixed value upwards, the temperature of the spray water is lowered, if the result is downward, the temperature of the spray water is increased.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß als Festwert ein Wert mit einem Toleranzbereich gewählt wird.2. The method according to claim 1, characterized in that a value with a tolerance range is selected as the fixed value.
3. Verfahren nach einem der Ansprüche 1 und 2, dadurch gekennzeichnet, daß der Toleranzbereich wählbar ist. 3. The method according to any one of claims 1 and 2, characterized in that the tolerance range is selectable.
PCT/EP1989/000143 1988-02-17 1989-02-16 Process for controlling a pulp grinder WO1989007687A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
NO894118A NO894118D0 (en) 1988-02-17 1989-10-16 PROCEDURE FOR REGULATING A TRIPLIPER.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP3804869.8 1988-02-17
DE19883804869 DE3804869A1 (en) 1988-02-17 1988-02-17 METHOD FOR CONTROLLING A WOOD GRINDER

Publications (1)

Publication Number Publication Date
WO1989007687A1 true WO1989007687A1 (en) 1989-08-24

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PCT/EP1989/000143 WO1989007687A1 (en) 1988-02-17 1989-02-16 Process for controlling a pulp grinder

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EP (1) EP0364516A1 (en)
DE (1) DE3804869A1 (en)
WO (1) WO1989007687A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998053377A1 (en) * 1997-05-23 1998-11-26 Interholz Technik Gmbh Adjustment system and method for adjusting operating speeds in wood processing

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1981001303A1 (en) * 1979-11-08 1981-05-14 Stroemberg Oy Ab A method for controlling a piston fed wood grinder
US4294412A (en) * 1976-12-27 1981-10-13 Sca Development Aktiebolag Method and apparatus for controlling wood pulp grinding machines
FR2546196A1 (en) * 1983-05-20 1984-11-23 Voith Gmbh Automatic control of temp. and throughput of wood pulping machine

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3693891A (en) * 1971-06-24 1972-09-26 Norton S Remmer Wood grinding
US3776475A (en) * 1972-07-17 1973-12-04 Norton Co Automatic pulp grinder control
SE422088B (en) * 1978-11-24 1982-02-15 Mo Och Domsjoe Ab PROCEDURE FOR THE PREPARATION OF LINDOCELLOLUS CONTENT MATERIALS

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4294412A (en) * 1976-12-27 1981-10-13 Sca Development Aktiebolag Method and apparatus for controlling wood pulp grinding machines
WO1981001303A1 (en) * 1979-11-08 1981-05-14 Stroemberg Oy Ab A method for controlling a piston fed wood grinder
FR2546196A1 (en) * 1983-05-20 1984-11-23 Voith Gmbh Automatic control of temp. and throughput of wood pulping machine

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PAPIER vol. 39, no. 10A, 01 Oktober 1985, DARMSTADT,DEUTSCHLAND Seite V147 - V152; MEINECKE: "DIE ENTWICKLUNG DES THERMOSCHLEIFENS" siehe das ganze Dokument *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998053377A1 (en) * 1997-05-23 1998-11-26 Interholz Technik Gmbh Adjustment system and method for adjusting operating speeds in wood processing

Also Published As

Publication number Publication date
EP0364516A1 (en) 1990-04-25
DE3804869A1 (en) 1989-08-31

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