WO1992017642A1 - Diagnosing disturbances in the wet part chemistry of a paper machine - Google Patents

Diagnosing disturbances in the wet part chemistry of a paper machine Download PDF

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Publication number
WO1992017642A1
WO1992017642A1 PCT/FI1992/000103 FI9200103W WO9217642A1 WO 1992017642 A1 WO1992017642 A1 WO 1992017642A1 FI 9200103 W FI9200103 W FI 9200103W WO 9217642 A1 WO9217642 A1 WO 9217642A1
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WO
WIPO (PCT)
Prior art keywords
signals
pieces
normal
unit processes
quantities
Prior art date
Application number
PCT/FI1992/000103
Other languages
French (fr)
Inventor
Martin Holmberg
Karl HOLMSTRÖM
Timo Korpi
Ismo Penttinen
Risto Ritala
Original Assignee
Oy Keskuslaboratorio - Centrallaboratorium Ab
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 Oy Keskuslaboratorio - Centrallaboratorium Ab filed Critical Oy Keskuslaboratorio - Centrallaboratorium Ab
Publication of WO1992017642A1 publication Critical patent/WO1992017642A1/en

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
    • D21H23/78—Controlling or regulating not limited to any particular process or apparatus
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G9/00—Other accessories for paper-making machines
    • D21G9/0009—Paper-making control systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/34—Paper
    • G01N33/343—Paper pulp

Definitions

  • the present invention concerns the diagnosing of disturbances in the wet part chemistry of a paper machine.
  • the invention concerns a proce ⁇ dure for locating pieces od apparatus and/or unitary processes which cause trouble in the wet part of a paper machine.
  • the invention concerns the respective apparatus.
  • paper is under ⁇ stood to mean common paper, cardboard or any other web- type product manufactured by an equivalent process.
  • Disturbances in the chemistry in the wet part of a paper machine are significant in view of the paper machine's production economy.
  • the losses of production caused by disturbances in the chemistry amount to e.g. 2 to 10% of the efficiency rate.
  • disturbances of the chemistry cause lowered quality level of the production.
  • the chemistry in the wet part of a paper ma ⁇ chine is a most complicated, strongly interactive sys ⁇ tem.
  • the system starts on the separate slurry lines, which have an effect on the circulation in the wet end and further on the paper, and which further influences the wet end chemistry through rejection.
  • Other factors also affecting the wet end chemistry include various mixing phases, various pumping phases, the admixing of chemicals and, on the whole, all the process steps, functions and conditions of the wet part.
  • the object of the present invention is to eliminate the drawbacks just mentioned and, in particu ⁇ lar, to improve the runability of a paper machine's wet part by teaching improved control of the wet end chem ⁇ istry, particularly by eliminating disturbances arising from precipitations and/or microbes and by monitoring the ion concentrations accumulating in the short cir ⁇ culation. It is a further object of the invention, to improve the runability of the wet part by eliminating trouble caused by disturbances in the chemistry.
  • the invention is based on continuous monitor ⁇ ing of the paper machine's wet part chemistry.
  • the fol ⁇ lowing at least, are continuously detected in the wet part: consistency, pH, conductivity, and dosage flows, and in addition the Ca, Al and silicate ion concentra ⁇ tions; the respective signals are continuously observed and in trouble situations when any one signal deviates from normal, one endeavours to find the process device which causes a disturbance in that particular quantity, by observing the occurrence of that disturbance in dif ⁇ ferent measured quantities and at different points of measurement and by eliciting the cause-and-effect rela ⁇ tionships between signals by means of time series analysis.
  • TOC Total Organic Carbon
  • the process of monitoring the quantities and of comparing such ob ⁇ servations of signal shape or frequency which differ from the normal values of the quantities in question in order to locate the causative source responsible for the disturbance of the particular quantity in the sig ⁇ nal shape of the quantities measured at the locations of devices in the preceding process phase, is accom- pushed, for instance, with a micro-processor.
  • the nor ⁇ mal level of a signal is in this context understood to be the signal intensity within given accepted limits of variation; particularly good results have been obtained by observing the signal shape. It is further possible in the procedure, when desired, to determine the ratio of at least two signals that have been formed, e.g.
  • a normal level and normal characteristic may be determined for such a de- layed ratio and for the transmission properties of the disturbance, and this can be compared, when desired, with the periodicity of those devices which affect the ratio.
  • the detection of said quantities and the form- ing of corresponding signals, and their further proces ⁇ sing, belong to analysing technology and amplifying technology known in themselves in the art and shall not be considered in any greater detail in this connection.
  • the summing of a given signal and/or the forming of a delayed ratio for comparison of their sum and/or ratio belongs to signal processing technology known in itself in the art and shall not be described in this connection.
  • a computing unit such as a micro-processor, for processing various signals, for comparisons, for processing and comparing signal periodicities, is in itself known in the art and shall not be considered in any greater detail in this con ⁇ nection.
  • the system according to the invention enables the chemistry in the wet part of a paper machine to be followed in great detail, and with high accuracy.
  • the source of this variation of ion concentration can be traced by following the propagation of the ion concen ⁇ tration variation, i.e., of the disturbance, in the process by the aid of determinations, and detectors, indicating the transmission path of the disturbance.
  • Abnormal variation of any one ion may thus be due, for instance, to a perturbed situation in the admixing of a chemical containing that ion, such as chemical feeding trouble, trouble with a feed pump, trouble with the subsequent slurry pump, etc.
  • consistency, flow, pH and conductivity the corresponding quantities are usually determined after mixing. Subsequent to the mixing phases it is usually appropriate to determine pH and conductivity. In connection with the headbox, it is usually appropri ⁇ ate to determine the ion concentrations, consistency, pH and conductivity. In connection with the wire well it is usually appropriate to determine consistency, pH and conductivity, and possibly the ion concentrations.
  • the novelty of the invention lies particularly in extensive, continuous chemical on-line observation of the wet end of the paper machine, and particularly in on-line observation of ions and concentrations, which has not heretofore been implemented in connection with the wet part of a paper machine.
  • a nov ⁇ elty in the invention is the forming of the delayed ratios of various signals and of the transfer proper ⁇ ties of disturbances moving between quantities, which possess significance especially in the location of sources of disturbances and of mechanisms in the pro ⁇ cess.
  • a novelty is furthermore comparison of the peri ⁇ odicity of signals from chemical detectors with the periodicity of pieces of apparatus which affect the respective quantity.
  • Fig. 1 is depicted a procedure and appara ⁇ tus according to the invention for locating the pieces of apparatus and/or the unit processes causing disturb ⁇ ance in the wet part of a paper machine.
  • the paper ma ⁇ chine includes a conventional wet part 31 with headbox 32 and dryer section 33.
  • the paper process and its com ⁇ ponents are known in themselves in the art and shall not be more closely described in this context.
  • the in ⁇ vention concerns in particular the locating of appara ⁇ tus and/or unit processes causing disturbances in the wet part of the paper machine.
  • chemical cellulose A, mechanical groundwood B and discard pulp C are fed into the wet part from re ⁇ spective tanks.
  • the pulp slurry is conducted into the machine tank 35, and further to mix ⁇ ing 36; then to vortex purifiers 37, to a pump 38, to sieves 39 and to the headbox 32. From the headbox the slurry is conducted to the wire section 31; the web that is formed in this section is conducted, in conven ⁇ tional manner, to the dryer section 33 and to product output, e.g. to be reeled, 40.
  • the slurry that has gone through the wire is conducted to the wire well 20, to be returned through mixing 36 to the slurry feed line.
  • the addition of chemicals may be accomplished, for in ⁇ stance, in a mixing tank 23. Chemicals may further be admixed e.g. to the contents of the machine tank 35. Furthermore, in the process of the figure chemicals are supplied to the pump 38 and fillers, to the tank 41, to be admixed to the slurry line in a mixing tank 21.
  • TA consistency, total consistency, pH, and conductivity employing the respective detectors l 1 , l 2 , 2 and 3; forming of signals and their transfer to the calculating unit 30, as abo ⁇ ve.
  • chemical 1, e.g. magnesium on the pump 38, chemical 3, any one further desired chemical, and from the filler tank 41, the desired filler material, employing respec ⁇ tive detectors as shown in the figure; forming of sig ⁇ nals and their transfer to the calculating unit 30, as above.
  • TOC is also determined from the headbox, i.e., the total quantity of organic carbon, employing the respective detector 19.
  • continuous, on-line detection is exercised of the periodicities of the pieces of apparatus and/or unit processes which in the preceding process phase affect the quantities that have been detected, e.g. the flow in the groundwood tank 46, the flow in the cellulose tank 45, the flow in the discard tank 47, the flow or pressure fluctuation in the mixing tank 34, the flow and/or pressure fluctuation in the machine tank 35, the flow and/or pressure fluctuations from the vortex puri- bombs 37 and 37 1 , the chemical 3, the flow and/or pres ⁇ sure fluctuation from the pump 38, the flow and/or pressure fluctuation at the sieves 39 ; forming of sig ⁇ nals and their transfer to the calculating unit 30, as above.
  • detectors D e.g. the operation of all pumps or of those pumps which are desired, of mixers and other machine elements and/or unit processes; form ⁇ ing of signals and their transfer to the calculating unit 30, as above.
  • signals represent ⁇ ing the periodicity of any desired quantities, devices and/or unit processes are formed.
  • the normal levels and normal characteristics of the signals and/or the trans ⁇ fer characteristics between signals, and signals devi ⁇ ating from normal are determined and compared with the detected periodicities of the apparatus and/or unit processes in the preceding process phase, in order to locate the cause of disturbance in the respective quan ⁇ tity.
  • the following, in particular, are observed in the present invention: consistency of slurry flows, their pH and conductivity, and the Ca, Al and silicate ion concentrations.
  • the process devices and/or unit proces- ses may be selected according to the target of study, for instance, the devices and/or unit processes most liable to disturbances would be observed in the first place.
  • the exemplary embodiment illustrates an appli- cation of the invention by way of example, without in any way confining the embodiments of the invention. It is thus understood that in the procedure and apparatus of the invention the concentration of any chemical or ion in the process may be observed, in a similar pro- cedure any function of any single device or machine element, or unit process, may be observed, e.g. pres ⁇ sure fluctuation, speed of rotation, particular vibra- tions, or equivalent.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Paper (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

A procedure and apparatus for locating the pieces of apparatus and/or unit processes causing disturbances in the wet part of a paper machine, said apparatus comprising detectors (1, 2, 3) for detecting consistency, pH and conductivity of the pulp slurry, detectors (4, 5, 6) for detecting the Ca, Al and silicate ion concentrations of the slurry, continuously on line, members (13 to 21) for detecting the periodicity of pieces of apparatus and/or unit processes, and a calculating unit (30) disposed to determine the normal levels of the signals, their normal characteristics and/or the transfer characteristics between signals and to determine the signal deviating from normal and to compare it with the detected periodicities of pieces of apparatus and/or unit processes in the preceding process phase, in order to locate the source causing the disturbance in the quantity in question.

Description

DIAGNOSING DISTURBANCES IN THE WET PART CHEMISTRY OF A PAPER MACHINE
The present invention concerns the diagnosing of disturbances in the wet part chemistry of a paper machine. In particular, the invention concerns a proce¬ dure for locating pieces od apparatus and/or unitary processes which cause trouble in the wet part of a paper machine. Furthermore, the invention concerns the respective apparatus.
In the present description, paper is under¬ stood to mean common paper, cardboard or any other web- type product manufactured by an equivalent process.
Disturbances in the chemistry in the wet part of a paper machine are significant in view of the paper machine's production economy. The losses of production caused by disturbances in the chemistry amount to e.g. 2 to 10% of the efficiency rate. Moreover, disturbances of the chemistry cause lowered quality level of the production.
The chemistry in the wet part of a paper ma¬ chine is a most complicated, strongly interactive sys¬ tem. The system starts on the separate slurry lines, which have an effect on the circulation in the wet end and further on the paper, and which further influences the wet end chemistry through rejection. Other factors also affecting the wet end chemistry include various mixing phases, various pumping phases, the admixing of chemicals and, on the whole, all the process steps, functions and conditions of the wet part.
The dynamics of the wet part chemistry of a paper machine are problematic. The time constants of the process components vary within wide limits, start¬ ing at the level of about 1 min. , and continuing up to several days. It is also a fact that laboratory deter¬ minations cannot be made frequently and comprehensively enough. Furthermore, on-line pick-ups are usually em- ployed rather sparingly.
The object of the present invention is to eliminate the drawbacks just mentioned and, in particu¬ lar, to improve the runability of a paper machine's wet part by teaching improved control of the wet end chem¬ istry, particularly by eliminating disturbances arising from precipitations and/or microbes and by monitoring the ion concentrations accumulating in the short cir¬ culation. It is a further object of the invention, to improve the runability of the wet part by eliminating trouble caused by disturbances in the chemistry.
It is a further object of the invention, to improve the uniformity of quality by eliminating qual- ity disturbances arising from variations of retention. It is a further object of the invention, to disclose a novel procedure and apparatus for determin¬ ing which of the machine elements cause malfunction in the wet part of a paper machine. Regarding the features which characterize the invention, reference is made to the claims.
The invention is based on continuous monitor¬ ing of the paper machine's wet part chemistry. The fol¬ lowing, at least, are continuously detected in the wet part: consistency, pH, conductivity, and dosage flows, and in addition the Ca, Al and silicate ion concentra¬ tions; the respective signals are continuously observed and in trouble situations when any one signal deviates from normal, one endeavours to find the process device which causes a disturbance in that particular quantity, by observing the occurrence of that disturbance in dif¬ ferent measured quantities and at different points of measurement and by eliciting the cause-and-effect rela¬ tionships between signals by means of time series analysis.
In addition to the quantities and ion concen¬ trations just mentioned, several other quantities may be determined from the slurry, e.g. turbidity, charge state, sulphate concentration, Fe, Mg and TOC concen¬ trations (TOC = Total Organic Carbon), and other ion concentrations and organic compounds as may be desired. In the procedure one may determine the signals corres¬ ponding to said quantities, the normal levels of the signals and their normal characteristics. The process of monitoring the quantities and of comparing such ob¬ servations of signal shape or frequency which differ from the normal values of the quantities in question in order to locate the causative source responsible for the disturbance of the particular quantity in the sig¬ nal shape of the quantities measured at the locations of devices in the preceding process phase, is accom- pushed, for instance, with a micro-processor. The nor¬ mal level of a signal is in this context understood to be the signal intensity within given accepted limits of variation; particularly good results have been obtained by observing the signal shape. It is further possible in the procedure, when desired, to determine the ratio of at least two signals that have been formed, e.g. the delayed ratio of two ion concentrations and the transmission properties of the disturbance progressing between them, the ratio of an ion concentration and another quantity, or the de¬ layed ratio of two concentrations other than ion con¬ centrations and the transmission properties of the dis¬ turbance progressing between them. A normal level and normal characteristic may be determined for such a de- layed ratio and for the transmission properties of the disturbance, and this can be compared, when desired, with the periodicity of those devices which affect the ratio.
The detection of said quantities and the form- ing of corresponding signals, and their further proces¬ sing, belong to analysing technology and amplifying technology known in themselves in the art and shall not be considered in any greater detail in this connection. Furthermore, the summing of a given signal and/or the forming of a delayed ratio for comparison of their sum and/or ratio belongs to signal processing technology known in itself in the art and shall not be described in this connection. Furthermore, a computing unit, such as a micro-processor, for processing various signals, for comparisons, for processing and comparing signal periodicities, is in itself known in the art and shall not be considered in any greater detail in this con¬ nection.
The system according to the invention enables the chemistry in the wet part of a paper machine to be followed in great detail, and with high accuracy. In a perturbed situation, e.g. when any one ion concentra¬ tion fluctuates within abnormally wide limits, the source of this variation of ion concentration can be traced by following the propagation of the ion concen¬ tration variation, i.e., of the disturbance, in the process by the aid of determinations, and detectors, indicating the transmission path of the disturbance. Abnormal variation of any one ion may thus be due, for instance, to a perturbed situation in the admixing of a chemical containing that ion, such as chemical feeding trouble, trouble with a feed pump, trouble with the subsequent slurry pump, etc.
In the system of the invention it is possible to place in the process of the wet part of the paper machine, e.g. in the chemical slurry line, in the me- chanical slurry line, in the discard line, in the mix¬ ing tank, in „ he machine tank, in connection with dilu¬ tion, in connection with the vortex purifier, in con¬ nection with the pumps, in connection with the sieves, in connection with the headbox and/or in connection with the wire well, a plurality, even several score, such as 10 to 100, of detectors for detecting chemical quantities as .taught by the invention. Furthermore, it is possible to place on the corresponding pieces of mechanical apparatus, such as pumps, feeders, pipe¬ lines, tanks, and other pieces of apparatus which me¬ chanically affect the slurry, various physical detec- tors, such as detectors sensing the operating state of the functions of respective apparatus. From the detec¬ tors, the signals are conducted, after signal proces¬ sing and amplification, if any, e.g. to a conventional computer, in which the process monitoring takes place. It is then possible, through said calculating unit, to observe each quantity that is being measured, and to determine any desired delayed ratios of quantities and transfer properties of disturbances between quanti¬ ties, and to compare quantities with each other. It is advantageous, in connection with the slurry lines, to determine e.g. consistency, flow, pH and conductivity; the corresponding quantities are usually determined after mixing. Subsequent to the mixing phases it is usually appropriate to determine pH and conductivity. In connection with the headbox, it is usually appropri¬ ate to determine the ion concentrations, consistency, pH and conductivity. In connection with the wire well it is usually appropriate to determine consistency, pH and conductivity, and possibly the ion concentrations. The novelty of the invention lies particularly in extensive, continuous chemical on-line observation of the wet end of the paper machine, and particularly in on-line observation of ions and concentrations, which has not heretofore been implemented in connection with the wet part of a paper machine. Moreover, a nov¬ elty in the invention is the forming of the delayed ratios of various signals and of the transfer proper¬ ties of disturbances moving between quantities, which possess significance especially in the location of sources of disturbances and of mechanisms in the pro¬ cess. A novelty is furthermore comparison of the peri¬ odicity of signals from chemical detectors with the periodicity of pieces of apparatus which affect the respective quantity.
In Fig. 1 is depicted a procedure and appara¬ tus according to the invention for locating the pieces of apparatus and/or the unit processes causing disturb¬ ance in the wet part of a paper machine. The paper ma¬ chine includes a conventional wet part 31 with headbox 32 and dryer section 33. The paper process and its com¬ ponents are known in themselves in the art and shall not be more closely described in this context. The in¬ vention concerns in particular the locating of appara¬ tus and/or unit processes causing disturbances in the wet part of the paper machine. In the process depicted in Fig. 1, chemical cellulose A, mechanical groundwood B and discard pulp C are fed into the wet part from re¬ spective tanks. After mixing 34, the pulp slurry is conducted into the machine tank 35, and further to mix¬ ing 36; then to vortex purifiers 37, to a pump 38, to sieves 39 and to the headbox 32. From the headbox the slurry is conducted to the wire section 31; the web that is formed in this section is conducted, in conven¬ tional manner, to the dryer section 33 and to product output, e.g. to be reeled, 40.
The slurry that has gone through the wire is conducted to the wire well 20, to be returned through mixing 36 to the slurry feed line.
In the principle process here depicted, the addition of chemicals may be accomplished, for in¬ stance, in a mixing tank 23. Chemicals may further be admixed e.g. to the contents of the machine tank 35. Furthermore, in the process of the figure chemicals are supplied to the pump 38 and fillers, to the tank 41, to be admixed to the slurry line in a mixing tank 21.
In the process of Fig. 1 determinations are made in the chemical pulp tank 45, the mechanical pulp tank 46 and the reject slurry tank 47, of the consis¬ tency, pH, conductivity and feed flow of the slurries. using the respective detectors 1, 2, 3 and 32. The re¬ sults of measurement D that are detected are conducted to a signal processing unit S, and further to a calcu¬ lating unit 30, that is, to a computer. From the ma- chine tank 35 are also determined: consistency, pH, conductivity and flow, and in addition the chemical 2, e.g. iron, using respective detectors; the signals are formed and conducted to the calculating unit 30 in like manner as above. Similarly, from the headbox 32 and from the wire well 20 are determined: TA consistency, total consistency, pH, and conductivity, employing the respective detectors l1, l2, 2 and 3; forming of signals and their transfer to the calculating unit 30, as abo¬ ve. Further, in the mixing tank 34 are determined: chemical 1, e.g. magnesium, on the pump 38, chemical 3, any one further desired chemical, and from the filler tank 41, the desired filler material, employing respec¬ tive detectors as shown in the figure; forming of sig¬ nals and their transfer to the calculating unit 30, as above. Furthermore, from the headbox are determined, at least, the Ca, Al and silicate ion concentrations, em¬ ploying respective detectors 4, 5 and 6; forming of signals and their transfer to the calculating unit 30, as above. In the embodiment here presented, TOC is also determined from the headbox, i.e., the total quantity of organic carbon, employing the respective detector 19.
Furthermore, in the embodiment here presented, continuous, on-line detection is exercised of the periodicities of the pieces of apparatus and/or unit processes which in the preceding process phase affect the quantities that have been detected, e.g. the flow in the groundwood tank 46, the flow in the cellulose tank 45, the flow in the discard tank 47, the flow or pressure fluctuation in the mixing tank 34, the flow and/or pressure fluctuation in the machine tank 35, the flow and/or pressure fluctuations from the vortex puri- fiers 37 and 371, the chemical 3, the flow and/or pres¬ sure fluctuation from the pump 38, the flow and/or pressure fluctuation at the sieves 39 ; forming of sig¬ nals and their transfer to the calculating unit 30, as above. Furthermore, one may in the procedure observe with separate detectors D, e.g. the operation of all pumps or of those pumps which are desired, of mixers and other machine elements and/or unit processes; form¬ ing of signals and their transfer to the calculating unit 30, as above.
In ths calculating unit 30, signals represent¬ ing the periodicity of any desired quantities, devices and/or unit processes are formed. In the calculating unit are further determined the normal levels and normal characteristics of the signals and/or the trans¬ fer characteristics between signals, and signals devi¬ ating from normal are determined and compared with the detected periodicities of the apparatus and/or unit processes in the preceding process phase, in order to locate the cause of disturbance in the respective quan¬ tity. The following, in particular, are observed in the present invention: consistency of slurry flows, their pH and conductivity, and the Ca, Al and silicate ion concentrations. The process devices and/or unit proces- ses may be selected according to the target of study, for instance, the devices and/or unit processes most liable to disturbances would be observed in the first place.
The exemplary embodiment illustrates an appli- cation of the invention by way of example, without in any way confining the embodiments of the invention. It is thus understood that in the procedure and apparatus of the invention the concentration of any chemical or ion in the process may be observed, in a similar pro- cedure any function of any single device or machine element, or unit process, may be observed, e.g. pres¬ sure fluctuation, speed of rotation, particular vibra- tions, or equivalent.
The embodiments of the invention may vary within the scope of the claims following below.

Claims

W092/H610 CLAIMS
1. A procedure for locating pieces of appara¬ tus and/or unit processes causing disturbances in the 5 wet part of a paper machine, at least the consistency, pH and conductivity being determined from the pulp slurry, c h a r a c t e r i z e d in that the Ca, Al and silicate ion concentrations are determined from the slurry continuously, on line; signals corresponding to 10 the detected quantities are formed; the normal levels and normal characteristics of said signals and/or the transfer characteristics between signals are determin¬ ed; the signals are continuously observed and compared with the respective normal levels and normal character- 15 istics; in case any one signal deviates from the re¬ spective normal level and normal characteristic, the periodicities of the pieces of apparatus and/or unit processes affecting the quantity in question are deter¬ mined in at least one preceding process phase and com- 20 pared with the fluctuations of the signal which devi¬ ates from normal, in order to locate the cause of the disturbance in the quantity in question.
2. Procedure according to claim 1, c a r¬ a c t e r i z e d in that from the slurry are detec- 25 ted the Fe, Mg and/or TOC concentrations concentrati¬ ons, continuously on line, corresponding signals are formed, the normal levels and characteristic of the signals and the transfer characteristics between sig¬ nals are determined, the signals are observed and com- 30 pared with the corresponding normal levels and charac¬ teristics, and the periodicities of the pieces of appa¬ ratus and/or unit processes affecting the quantities in question are compared with the fluctuations of the signal deviating from normal. 35
3. Procedure according to claim 1 or 2, c h a r a c t e r i z e d in that in the procedure the shape of the signals of the quantities detected on line and the periodicity of the pieces of apparatus and/or unit processes affecting the shape are continuously observed.
4. Procedure according to any one of claims 1-3, c h a r a c t e r i z e d in that in the proce¬ dure are determined the ratio of at least two signals that have been formed, their delayed ratio and/or the transfer characteristics of the disturbance progressing between them and the quantity thus obtained is compared with the periodicity of the pieces of apparatus and/or unit processes affecting said ratio.
5. Apparatus for locating the pieces of apparatus and/or unit processes causing disturbances in the wet part of a paper machine, said apparatus com- prising detectors (1,2,3) for detecting consistency, pH and conductivity of the pulp slurry, c h a r a c t e¬ r i z e d in that the apparatus comprises detectors (4,5,6) for detecting the Ca, Al and silicate ion con¬ centrations of the slurry, continuously on line, mem- bers (S) for forming signals corresponding to the quan¬ tities detected, members (13 to 21) for detecting the periodicity of the pieces of apparatus and/or unit processes affecting said quantities in one preceding process phase at least, and a calculating unit (30) disposed to determine the normal levels of the signals, their normal characteristics and/or the transfer cha¬ racteristics between signals and to determine the sig¬ nal deviating from normal and to compare it with the detected periodicities of pieces of apparatus and/or unit processes in the preceding process phase, in order to locate the source causing the disturbance in the quantity in question.
6. Apparatus according to claim 5, c h a r a c t e r i z e d in that the apparatus comp- rises detectors (7,8,9) for detecting the Fe, Mg and/or TOC concentration, continuously on line, and members (S) for forming signals corresponding to the quantities that have been detected.
7. Apparatus according to claim 5 or 6, c h a r a c t e r i z e d in that the calculating unit (30) is disposed to compare the shape of the signals of quantities detected continuously, on line, and the periodicity of pieces of apparatus and/or unit proces¬ ses affecting the shape.
8. Apparatus according to any one of claims 5-7, c h a r a c t e r i z e d in that the apparatus comprises members for forming the ratio or the delayed ratio of at least two signals and/or the transfer cha¬ racteristics of the disturbance progressing between them, and that the calculating unit (30) is disposed to compare the ratio that has been formed with the pe- riodicities of the pieces of apparatus and/or unit processes (13 to 21) in the preceding process phase.
PCT/FI1992/000103 1991-04-08 1992-04-03 Diagnosing disturbances in the wet part chemistry of a paper machine WO1992017642A1 (en)

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FI911685A FI92742C (en) 1991-04-08 1991-04-08 Diagnosis of paper machine wet chemistry disorders

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998028490A1 (en) * 1996-12-20 1998-07-02 Siemens Aktiengesellschaft Method and device for conducting a process in the production of paper
US5842150A (en) * 1994-10-14 1998-11-24 Eka Chemicals Ab Method of determing the organic content in pulp and paper mill effulents
WO1999001612A1 (en) * 1997-07-01 1999-01-14 Andritz-Patentverwaltungs-Gesellschaft Mbh Method for minimizing water use in a water circuit in a paper, cellulose or wood factory
EP0902119A2 (en) * 1997-09-16 1999-03-17 Metsä-Serla Oy Process for preparing a paper web
EP1089149A2 (en) 1999-09-29 2001-04-04 Focke & Co. (GmbH & Co.) Method and device for diagnosing machines

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4752356A (en) * 1985-10-18 1988-06-21 Miami University Papermaking process

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4752356A (en) * 1985-10-18 1988-06-21 Miami University Papermaking process

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
TAPPI JOURNAL, Vol. 70, No. 1, January 1987, ALLAN M. SPRINGER et al.: "Fundamental strategy for control of retention and drainage on a modern paper machine", see page 43 - page 45. *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5842150A (en) * 1994-10-14 1998-11-24 Eka Chemicals Ab Method of determing the organic content in pulp and paper mill effulents
EP0786082B1 (en) * 1994-10-14 2000-01-19 Eka Chemicals AB A method of determining the organic content in pulp and paper mill effluents
WO1998028490A1 (en) * 1996-12-20 1998-07-02 Siemens Aktiengesellschaft Method and device for conducting a process in the production of paper
WO1999001612A1 (en) * 1997-07-01 1999-01-14 Andritz-Patentverwaltungs-Gesellschaft Mbh Method for minimizing water use in a water circuit in a paper, cellulose or wood factory
EP0902119A2 (en) * 1997-09-16 1999-03-17 Metsä-Serla Oy Process for preparing a paper web
EP0902119A3 (en) * 1997-09-16 1999-08-11 Metsä-Serla Oy Process for preparing a paper web
EP1089149A2 (en) 1999-09-29 2001-04-04 Focke & Co. (GmbH & Co.) Method and device for diagnosing machines

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FI92742C (en) 1994-12-27
FI911685A0 (en) 1991-04-08
FI911685A (en) 1992-10-09
FI92742B (en) 1994-09-15

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