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
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
  • D21H23/06—Controlling the addition
  • D21H23/12—Controlling the addition by measuring properties of the formed web
• • 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
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
  • D21H23/06—Controlling the addition
  • D21H23/08—Controlling the addition by measuring pulp properties, e.g. zeta potential, pH
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S162/00—Paper making and fiber liberation
  • Y10S162/09—Uses for paper making sludge
  • Y10S162/10—Computer control of paper making variables
  • Y10S162/11—Wet end paper making variables

Definitions

• the invention relates to a method for controlling the addition of retention aid in papermaking.
• the paper produced be as uniform as possible, i.e. H. has a good formation.
• the retention and flocculant addition increases. This means that with the control mentioned above, the retention values at which the formation is still acceptable must first be found by preliminary tests. They are then used as setpoints for the control.
• the formation is still dependent on the respective paper stock composition, so that this setting must be carried out for each type of paper running on the paper machine. But even then it is still not certain whether a good formation will be achieved since fluctuations in the quality of the raw materials used cannot be recorded.
• the degree of flocculation of the pulp suspension is first measured in the paper machine.
• the retention is measured with the known systems described above, the degree of flocculation also with known systems, for example with a flocculation sensor according to EP-A-01 57 310.
• the computer continuously receives measurement data of the variable pulp values or quantities, so that for a setpoint value to be entered for the degree of flocculation, namely the maximum permissible degree of flocculation (Y2), the maximum quantity of the variable material components (X i ... X n ) can be determined.
• Control signals for metering devices, for example metering pumps, of these components are then derived from the quantity values.
• the retention (Y1) depends on the variable pulp values (X1 ... X n ), so that there is an optimal combination of the addition quantities of the variable material components influencing the retention, in which there is a setpoint for the degree of flocculation sets a maximum retention.
• the quantity values of these variable components (X i ... X n ) in the instantaneous setting of the paper stock values (X 1 ... X i-1 ) are varied in such a way that a combination of the values is found in which both the equation (II) for the setpoint of the Degree of flocculation (Y2) is met, and a maximum retention (Y1) of the pulp according to equation (I) is achieved.
• the control signals for the corresponding metering devices for the variable substance components are in turn derived from the quantity values obtained in this way.

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• Paper (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=6358029

Family Applications (1)

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Cited By (1)

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• 1988
  • 1988-07-06 DE DE3822783A patent/DE3822783A1/de not_active Withdrawn
• 1989
  • 1989-06-14 US US07/366,495 patent/US4952280A/en not_active Expired - Fee Related
  • 1989-06-24 EP EP19890111530 patent/EP0349860A3/fr not_active Withdrawn
  • 1989-06-28 JP JP1164095A patent/JPH0247386A/ja active Pending
  • 1989-07-03 FI FI893232A patent/FI893232L/fi not_active Application Discontinuation

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