EP0306921A2 - Procédé de réglage d'un broyeur agitateur - Google Patents

Procédé de réglage d'un broyeur agitateur Download PDF

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Publication number
EP0306921A2
EP0306921A2 EP88114616A EP88114616A EP0306921A2 EP 0306921 A2 EP0306921 A2 EP 0306921A2 EP 88114616 A EP88114616 A EP 88114616A EP 88114616 A EP88114616 A EP 88114616A EP 0306921 A2 EP0306921 A2 EP 0306921A2
Authority
EP
European Patent Office
Prior art keywords
product
agitator mill
ground
mill
agitator
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP88114616A
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German (de)
English (en)
Other versions
EP0306921A3 (fr
Inventor
Wolfgang Heinritz
Peter Schertenleib
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Erich Netzsch GmbH and Co Holding KG
Original Assignee
Erich Netzsch GmbH and Co Holding KG
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 Erich Netzsch GmbH and Co Holding KG filed Critical Erich Netzsch GmbH and Co Holding KG
Publication of EP0306921A2 publication Critical patent/EP0306921A2/fr
Publication of EP0306921A3 publication Critical patent/EP0306921A3/fr
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/16—Mills in which a fixed container houses stirring means tumbling the charge
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C25/00—Control arrangements specially adapted for crushing or disintegrating

Definitions

  • the invention relates to a method for controlling an agitator mill, in which a property of the ground product determines a predetermined period of time after the mill has started up and the speed of a product feed pump or the agitator and / or the grinding media filling level and / or the product retention time In accordance with the determined value of the property can be set.
  • Such a method is known from DE-A 36 23 833. It has already been stated there that various control methods are known (DE-A 29 32 783 and 30 38 794), in which a plurality of interlinked control systems are provided.
  • the fineness of the ground product is determined as a property and the value determined is introduced into the control link for the controlled system.
  • the gap size of the grinding media in the grinding container (which is also referred to as grinding media filling level) is primarily set there.
  • the person skilled in the art is familiar with how the grinding element gap degree or filling degree can be adjusted (see, for example, also DE-A 22 40 751 and DE-A 36 23 833).
  • the product fineness is used as the essential parameter for controlling the agitator mill.
  • measuring the fineness of the product is problematic.
  • a very complex device is provided for this, in which the deflection of a laser beam is measured will.
  • the product fineness should be calculated on the basis of a mathematical model solely from the operating data of the agitator mill. Both methods mentioned for determining the product fineness are very complex and expensive if sufficiently precise measured values are to be achieved.
  • the invention is based on the object of developing a generic method for controlling an agitator mill in such a way that good qualities of the ground product are ensured with the simplest possible operation with little expenditure on equipment.
  • this object is achieved in that a predetermined period of time after the mill has started up is measured at least one of the following properties of the ground product, namely gloss, transparency, color strength, capillary flow behavior, viscosity or pH, and at least one of the following operating parameters of the agitator mill the measured value is set, namely the speed of a mill feed pump, the speed of an agitator of the mill, the degree of filling of the grinding media or the grinding time in the agitator mill.
  • the gloss of the ground product can be determined in a simple manner by means of light rays and reflection measurements, for example as described in the lexicon ULLMANN, Verlag Chemie, Weinheim, 4th edition, 1978, volume 15, page 700.
  • the transparency of ground product can also be determined in a simple, conventional manner by measuring the absorbance. A light beam of precisely defined composition is directed onto a defined layer of the ground product and the light passing through is measured.
  • the measurement of the color strength is also known per se to the person skilled in the art.
  • the product is irradiated with defined light and the spectral emission is measured for certain wavelengths with regard to their intensity.
  • a measuring method for determining the color strength can be found, for example, in the publication SENSOR REPORT, 4/1987, pages 8 to 13 (essay by Henri Hencke).
  • the measurement of the capillary flow behavior is also known per se to the person skilled in the art. This process is used in particular in the manufacture of textile dyes. For this purpose, a line-shaped color sample with a precisely defined amount is applied to the surface of a non-woven material and the width of the line is then measured, which gives a measure of the flowability of the dye.
  • the measurement of the viscosity is also known per se to the person skilled in the art. Although the viscosity also depends on the fineness of the ground product, it also includes other phenomena, such as adhesive forces between the individual regrind bodies. Solvents and binders as well as other additives also influence the viscosity.
  • Microorganisms are also processed in agitator mills today. According to the invention, the measurement of the pH value plays an important role here. Microorganisms, in particular their cell envelope, are not reduced in size, but only broken down, as a result of which the cell contents can escape and can be separated according to the composition. In a first approximation, the measured pH value gives a guideline for the degree of digestion when processing microorganisms. Acids are released during cell disruption. The more acid is released, the higher the cell disruption. It can therefore be assumed that the cell disruption is completed at a pH of about 3 to 4.
  • the agitator mill can thus be controlled on the basis of a measurement of the pH value and, if, for example, the desired pH value has not yet been reached, the throughput Speed or the operating time can be changed.
  • the measurement of a pH value is known to the person skilled in the art. For example, an electrical conductivity or resistance measurement can be carried out.
  • At least one of the properties of the ground material is measured after a predetermined period of time after the agitator mill has started up. Several properties can also be measured if they are considered essential for the given product.
  • the operation of the agitator mill is then controlled in accordance with the measured values of the properties mentioned.
  • At least one of the above-mentioned operating parameters of the agitator mill is automatically set by a computer in accordance with the measurement result. If, for example, a predetermined period of time after the agitator mill has started up, it is found that the gloss of the ground product does not correspond to a desired value, then at least one of the operating parameters is optionally changed in accordance with previously empirically determined data in such a way that the desired value is achieved for the gloss. The same applies to the other properties or operating parameters.
  • the speed of a product feed pump regulated according to the invention essentially determines the throughput through the agitator mill, that is to say the amount of product ground per unit of time.
  • the product residence time is to be understood as the mean period of time in which the products in the agitator mill are exposed to the grinding process.
  • the product dwell time depends on the speed of the product feed pump, but is not necessarily determined by this alone.
  • the residence time of the product in the agitator mill can be extended without changing the speed of the product feed pump in that ground products at the outlet of the mill are fed back into the inlet of the mill and subjected to a renewed grinding process.
  • degree of filling of grinding media corresponds to the term “degree of gap”. It gives the ratio of the volume occupied by the grinding media in the grinding chamber to the volume free of grinding media.
  • the measured variables gloss, transparency, color strength, capillary flow behavior or viscosity used according to the invention for the control of the agitator mill also depend on the fineness of the product.
  • other properties of the product go into them. For example, when measuring the fineness of the product, an average grain size and possibly the average deviation from it are determined.
  • the properties of gloss, color strength, transparency, capillary flow behavior and viscosity depend in a complicated way on the particle size distribution, the surface conditions or agglomerations, whereby chemical influences can still occur.
  • the measured variables used according to the invention are thus not only much easier to measure than the fineness of the product, but also provide more precise information about the quality of the ground product which is actually of interest.
  • a particularly simple operation of the agitator mill results from the fact that, in previous experiments, optimally coordinated operating values for each of the product groups were determined with respect to the speed of the feed pump, the degree of filling of the grinding media and the dwell time.
  • optimally coordinated operating values for each of the product groups were determined with respect to the speed of the feed pump, the degree of filling of the grinding media and the dwell time.
  • the speed of the pump, the degree of filling and possibly the dwell time must be coordinated.
  • these functional dependencies between the individual operating parameters for achieving the best results are determined experimentally and stored in advance for each product group in the memory of a computer performing the method according to the invention and are later used in a grinding process to control the agitator mill.
  • the grinding media filling level of the agitator mill is not set primarily and, depending on this, the speed of the feed pump, but conversely the speed of the feed pump is set primarily as a determining operating variable to maximum throughput .
  • This maximum throughput corresponds to an associated value for the degree of filling, which, as described above, is determined experimentally in advance has been. In general, if the throughput (ie the speed of the feed pump) increases, the degree of filling is also increased proportionally if the fineness of the product is to remain the same.
  • the product dwell time does not only depend on the speed of the pump , but additionally set by means of a by-pass, via which ground product is removed from the exit of the agitator mill and returned to its entrance, so that it remains longer in the mill.
  • the removal of ground products from the mill for the aforementioned measurement purposes or for recycling does not necessarily have to take place at the exit of the agitator mill, but can also be carried out at a point between the entrance and exit of the mill.
  • a device according to the invention in which the specified functions are carried out, also corresponds to the method features described above.
  • FIG. 1 schematically shows an agitator mill 10 known per se (see, for example, DE-A 22 40 751).
  • the housing and the support the agitator mill 10 are indicated with the reference numerals 12 and 12 '.
  • the agitator mill has a displaceable pressure piston 14 known as such, with which the volume of the grinding chamber and thus the degree of filling can be changed.
  • the ground product is transferred from the agitator mill 10 into a collecting container 16.
  • the invention relates to the control of the operating parameters of the agitator mill 10, namely the speed of the feed pump, the degree of filling of the grinding media and the dwell time of the product to be ground in the agitator mill, depending on certain measured variables, namely the gloss, the transparency and the color strength of the ground product .
  • Fig. 1 shows the components required for this control.
  • the material to be ground is conveyed to the inlet E of the agitator mill via a feed pump 18 and feed lines 20, 26.
  • a pressure indicator and switch 22 and a valve 24 according to FIG. 1 are arranged on the inlet side.
  • the product After passing through the grinding chamber 28 and carrying out the grinding process, the product is conveyed to the collecting container 16 via the outlet A, the line 30 and the 3-way valve 32.
  • the current consumption of the agitator mill 10 is displayed and regulated by means of a current indicator and regulator 34.
  • the temperature of the ground material is displayed by means of a temperature indicator and controller 36 and regulated accordingly.
  • a level controller 38 and a flow indicator and controller 40 are speed-controlled via the speed indicator and regulator 18 ', the feed pump 18 and a further speed indicator and regulator 42, a further feed pump 44, whereby the throughput is determined by the agitator mill 10.
  • the speeds of the product feed pumps 18 and 44 first determine both the throughput through the grinding chamber 28 of the agitator mill 10 and the residence time of the products in the grinding chamber. 1, the 3-way valve 32 can be flipped over, so that ground product conveyed from outlet A can be returned via inlet 48 to inlet E of the grinding chamber. As a result, the dwell time of the products to be ground can be changed without changing the speed of the feed pumps 18, 44.
  • the operating parameters “speed of the pump”, “degree of filling of the grinding media” in the grinding chamber 28 and “residence time” have an effect on the gloss, the transparency and the color strength of the ground product.
  • the product temperature, the agitator current (flow indicator and regulator 34) and the grinding chamber pressure also have an impact on the properties of the ground product mentioned.
  • a first product group is the rotary printing inks, which are mainly used for printing newspapers.
  • Rotary printing inks contain carbon black as a colorant and fatty acids or stearin pitch as well as root or other resins as a binder.
  • Mineral oil distillates serve as oils.
  • Such rotary printing inks have a very low viscosity in the range of 100 p.
  • a second product group are the so-called heat set inks for offset printing.
  • Such heat set colors have organic or inorganic pigments as colorants.
  • Hard resins or alkyd resins are used as binders.
  • the viscosity of such heat set colors is typically 120 p.
  • the third product group differentiates between sheet printing and sheet offset inks.
  • Organic or inorganic pigments are also used here.
  • Medium and highly viscous alkyd resins and hard resins (phenolic resins) serve as binders. Drying oils such as wood oil or mineral oil are used.
  • the viscosity of such sheet printing and sheet offset inks is relatively high and is in the range from 170 to 250 p.
  • the colors are typically used for offset printing of maps, brochures, posters etc.
  • Each of the product groups described above is characterized in that the oil printing inks belonging to them require very similar operating parameters when operating the agitator mill in order to achieve good values in terms of gloss, transparency and color strength.
  • the optimum operating parameters are determined experimentally in advance for a particular agitator mill and stored in the memory of a computer (not shown) controlling the control elements according to FIG. 1.
  • the operator enters into the computer which product group the product to be ground belongs to.
  • the computer then automatically takes the optimal operating parameters for all control elements shown in FIG. 1 from the memory and adjusts them accordingly.
  • the user may only enter the product group and, in addition, optionally add individual operating parameters, such as, for. B. the throughput, the maximum product temperature and the maximum grinding chamber pressure.
  • the grinding process then starts with the preselected initial operating parameters. After a waiting period, which results from the dwell time of the product in the grinding chamber, it is indicated that a measurement of the ground product with regard to gloss and / or transparency and / or color strength makes sense, depending on which of the values mentioned for the product just ground is of interest.
  • the measurement is carried out using the methods known per se and is necessary because the above-described experimental preliminary determination of the optimal operating parameters for the individual product groups only provides relatively rough reference values.
  • the products to be ground can be supplied with different quality, so that corrections may be necessary during a grinding process.
  • the operation of the agitator mill 10 is controlled in such a way that the throughput and the degree of filling of the grinding media are always set proportionally to one another, in such a way that the throughput is always set to a maximum value and the degree of filling is then adjusted proportionately.
  • the proportionality factor has been previously determined and saved for the individual product groups.
  • the gloss of the ground product is essential, but not only determined by its fineness.
  • a good surface structure and a correspondingly good gloss also essentially depend on the fact that a very narrow grain size distribution is achieved, i.e. The ground product grains must be concentrated in the narrowest possible interval around the mean value of the fineness.
  • Such a grain size distribution which is favorable for the gloss is achieved with the arrangement according to FIG. 1 in that a bypass 48 is provided, via which product ground by means of the 3-way valve 32 is returned from the outlet A of the grinding chamber 28 to its inlet E. can, so that the residence time of the ground product in the grinding chamber is increased. It is also possible to vary the dwell time using a buffer mode.
  • the control of an agitator mill according to the invention was described above on the basis of the measured properties of gloss, transparency and color strength of the ground product.
  • the control of the agitator mill can accordingly be carried out by measuring the capillary flow behavior and the viscosity (the measurement of which is described above). For each regrind and product, it is determined which of the properties gloss, transparency, color strength, viscosity and capillary flow behavior is important.
  • desired target values are then specified with regard to these properties and compared with those measured a predetermined period of time after the agitator mill has started up. If there is a deviation, at least one of the operating parameters of the agitator mill is changed so that it can be expected that the property of the ground product is now closer to the target value. In the case of large deviations, a major change in an operating parameter takes place, whereas in the case of minor deviations, correspondingly smaller corrections of the operating parameter are required.
  • the required values are determined experimentally for each regrind and product and saved in the computer.
  • the pH value serves as an essential property for controlling the agitator mill.
  • the measured pH value provides information about the degree of digestion when processing microorganisms.
  • other properties mentioned above can also be essential and can be determined and used to control the agitator mill.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)
EP88114616A 1987-09-10 1988-09-07 Procédé de réglage d'un broyeur agitateur Withdrawn EP0306921A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19873730426 DE3730426A1 (de) 1987-09-10 1987-09-10 Verfahren zum regeln einer ruehrwerksmuehle
DE3730426 1987-09-10

Publications (2)

Publication Number Publication Date
EP0306921A2 true EP0306921A2 (fr) 1989-03-15
EP0306921A3 EP0306921A3 (fr) 1989-10-18

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP88114616A Withdrawn EP0306921A3 (fr) 1987-09-10 1988-09-07 Procédé de réglage d'un broyeur agitateur

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EP (1) EP0306921A3 (fr)
DE (1) DE3730426A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH684615GA3 (de) * 1992-03-10 1994-11-15 Buehler Ag Rührwerksmühle.
WO2014187824A1 (fr) 2013-05-21 2014-11-27 Flsmidth A/S Procédés et appareil de surveillance en continu de l'usure dans des circuits de meulage

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113083447B (zh) * 2021-04-10 2022-08-16 南京工程学院 大型冶炼高炉磨煤机球磨系统全自动智能减振控制方法及装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3038794A1 (de) * 1980-10-14 1982-05-27 Gebrüder Bühler AG, 9240 Uzwil Ruehrwerkskugelmuehle
DE3623833A1 (de) * 1985-07-18 1987-01-22 Buehler Ag Geb Verfahren zum regeln und ruehrwerksmuehle zur durchfuehrung des verfahrens
DE3614980C1 (de) * 1986-05-02 1993-05-27 Draiswerke Gmbh Regelungseinrichtung fuer eine Ruehrwerksmuehle
DE2932783C2 (de) * 1978-08-24 1993-09-30 Gebrüder Bühler AG, Uzwil Rührwerkskugelmühle-Regelung

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2932783C2 (de) * 1978-08-24 1993-09-30 Gebrüder Bühler AG, Uzwil Rührwerkskugelmühle-Regelung
DE3038794A1 (de) * 1980-10-14 1982-05-27 Gebrüder Bühler AG, 9240 Uzwil Ruehrwerkskugelmuehle
DE3623833A1 (de) * 1985-07-18 1987-01-22 Buehler Ag Geb Verfahren zum regeln und ruehrwerksmuehle zur durchfuehrung des verfahrens
DE3614980C1 (de) * 1986-05-02 1993-05-27 Draiswerke Gmbh Regelungseinrichtung fuer eine Ruehrwerksmuehle

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH684615GA3 (de) * 1992-03-10 1994-11-15 Buehler Ag Rührwerksmühle.
WO2014187824A1 (fr) 2013-05-21 2014-11-27 Flsmidth A/S Procédés et appareil de surveillance en continu de l'usure dans des circuits de meulage

Also Published As

Publication number Publication date
EP0306921A3 (fr) 1989-10-18
DE3730426A1 (de) 1989-03-23

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