EP0391015A1 - Système de caisse de tête - Google Patents

Système de caisse de tête Download PDF

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Publication number
EP0391015A1
EP0391015A1 EP89890096A EP89890096A EP0391015A1 EP 0391015 A1 EP0391015 A1 EP 0391015A1 EP 89890096 A EP89890096 A EP 89890096A EP 89890096 A EP89890096 A EP 89890096A EP 0391015 A1 EP0391015 A1 EP 0391015A1
Authority
EP
European Patent Office
Prior art keywords
headbox
cross
flow distributor
line
lines
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Withdrawn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
EP89890096A
Other languages
German (de)
English (en)
Inventor
Hans Albert
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to EP89890096A priority Critical patent/EP0391015A1/fr
Publication of EP0391015A1 publication Critical patent/EP0391015A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/02—Head boxes of Fourdrinier machines
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/06—Regulating pulp flow

Definitions

  • the invention relates to a headbox system for a paper machine, with a headbox and a cross flow distributor, a tube system being arranged between the headbox and the crossflow distributor and the crossflow distributor being connected to a material line at at least one end.
  • headbox systems have a headbox and a cross-flow distributor, with a tube system being arranged between the headbox and the cross-flow distributor, and the cross-flow distributor either being connected at one end to a feed line and at the other end to a return line or connected to a feed line at both ends , which are connected to an inlet, which in turn is connected to a material pump, forming a ring line.
  • Another disadvantage is that the air contained in the incoming material expands at the first opportunity and retroactively causes uneven speed / pressure ratios in the headbox system.
  • known paper machines suffer from a disadvantageous consequence of the uneven distribution of material in the headbox: If there is too little material in the middle of the headbox, the papermaker must open the cloth lip in the middle, i.e. adjust the concave course of the cloth lip so that there is more material there can emerge as on the edges. However, this has the consequence that, owing to the lower resistance present in the middle, a material flow occurs from the edges to the center, as a result of which a fiber inclination and a disadvantageous fiber orientation over the web width are required.
  • this poor fiber orientation leads to variations in the transverse / longitudinal tear strength of the paper web, uneven stretching, uneven shrinkage, uneven thickness and uneven stretching of the paper web in the manufacturing or processing section of the paper web following nips, such as those of wet presses, size presses, calenders, coaters etc.
  • the fabric lip must be set at an angle to the sieve, i.e. has a greater distance from the screen at one edge than at the other edge; in this case too, there is a material flow directed obliquely to the direction of wire travel with the disadvantages mentioned above.
  • the invention has for its object to overcome the problems listed and to eliminate the disadvantages mentioned.
  • the object is achieved with a headbox system of the type mentioned in the invention in that the crossflow distributor at both ends has extending, continuously connecting extensions beyond the headbox and that additional tubes are provided in the extensions are, which open outside the headbox, preferably in a common material return.
  • the material distribution in the headbox is evened out, so that the material emerges in a uniform passage quantity over the entire width of the fabric lip and no lip adjustment otherwise required due to uneven material distribution is required and the associated disadvantages are eliminated.
  • the fabric lip is only used for the purpose of fine adjustment of the amount of substance emerging.
  • cross flow distributor is connected to a material line at both ends, which with formation a ring line are connected to a common supply line, and that the material lines are connected to one another via a compensating line. This leads to a bilateral and thus symmetrical flow to the cross distributor. As a result of the inlet being divided in two, the cross-flow distributor can be dimensioned smaller.
  • the lines can be arranged in two rows one above the other, the lines of one row serving for pressure control and the lines of the other row for removal.
  • a return line is connected to each material line, a control valve is provided in each return line and the control valves are controlled by a differential pressure transmitter that is connected to pressure sensors located at the ends of the headbox is. This creates completely identical conditions on both sides of the headbox.
  • the extensions can be designed as separate components and adjustable in length. This length adjustability also allows a reduction until the pulsations occurring in the fabric, caused by fabric pumps, valves and the entrained air (which propagate at the speed of sound) are eliminated by interference.
  • each fabric line can have a length-adjustable section arranged adjacent to the associated extension, by means of which the above-mentioned effect is brought about or supported.
  • a number of tubes which are arranged next to one another in the running direction of the paper machine screen and are each arranged in the running direction of the paper machine screen, can be provided according to the invention, each of which is assigned a cutting device directed towards the paper machine screen.
  • These lines serve to correct the irregularities caused by the edge wave restrict a narrow edge zone, while the cutting devices serve to separate these edge zones from the rest of the paper web; the separated peripheral zones can be recycled if necessary.
  • FIG. 1 shows a top view of the headbox system according to the invention
  • FIG. 2 shows a top view of the cutting device
  • FIG. 3 shows a block diagram of the differential pressure transmitter.
  • the headbox system according to the invention for a paper machine has a headbox 1 and a crossflow distributor 2, a tube system 3 being arranged between the headbox 1 and the crossflow distributor 2.
  • the cross-flow distributor 2 is connected at its ends 2a, 2b to a material line 4a and 4b, respectively.
  • the material lines 4a, 4b are connected to one another to form a ring line and connected to a common supply line 5, which is connected to a material pump (not shown).
  • the two material lines 4a, 4b are connected to one another via an equalization line 6 arranged essentially parallel to the cross-flow distributor 2, several lines 7, each with an adjustable control valve 8, being provided between the cross-flow distributor 2 and the equalization line 6.
  • These lines 7 are preferably the same Distances arranged along the cross flow distributor 2 or the equalization line 6.
  • the control valves 8 can be set manually (for example clamps on rubber hoses), but are preferably electrically controllable and connected to an electronic process control system which is integrated in the process control system of the paper machine (not shown).
  • a return line 9a or 9b is connected to each material line 4a, 4b, in which there is a control valve 10a or 10b, which is controlled by a differential pressure transmitter 11, which in turn receives input signals from pressure sensors 12a, 12b connected to it, which at the ends the headbox 1 are attached.
  • the control valves 10, 10b used in the return lines 9a, 9b are controlled in such a way that in the cross-flow distributor 2 and thus in the tube system 3 supplied material are substantially uniform pressure and thus inflow conditions are impressed.
  • the cross flow distributor 2 has 2a, 2b at both ends Extending beyond the headbox 1, continuously adjoining extensions 13a, 13b, in which additional tubes 3a, 3b, which are arranged next to one another, are provided and which open outside the headbox 1. These tubes 3a, 3b expediently open into a manifold (not shown) which is connected to the return lines 9a, 9b.
  • a plurality of tubes 15a, 15b directed in the running direction of the screen are also provided side by side at the ends of the headbox 1, as is shown more clearly in FIG. 2.
  • a cutting device 16a, 16b for example in the form of a vertical ruler, is arranged in front of each most internal tube serve to separate the edge strips of the fabric.
  • each cutting device 16a, 16b is provided with a derivation 17a, 17b, through which the separated edge strips are derived.
  • FIG 3 shows a block diagram of the differential pressure transmitter 11 which is used to control the control valves 10a, 10b arranged in the return lines 9a, 9b as a function of the pressure prevailing at the two ends of the headbox 1, which pressure is detected by the pressure sensors 12a, 12b.
  • the length of the calming section and / or that of the material lines 4a, 4b are adjustable in length, which can be achieved by telescoping tubes. In this way, wave formation in the supplied material, which may originate from pulsations in the material pump, can be virtually completely eliminated by interference.

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  • Paper (AREA)
EP89890096A 1989-04-06 1989-04-06 Système de caisse de tête Withdrawn EP0391015A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP89890096A EP0391015A1 (fr) 1989-04-06 1989-04-06 Système de caisse de tête

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP89890096A EP0391015A1 (fr) 1989-04-06 1989-04-06 Système de caisse de tête

Publications (1)

Publication Number Publication Date
EP0391015A1 true EP0391015A1 (fr) 1990-10-10

Family

ID=8203298

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89890096A Withdrawn EP0391015A1 (fr) 1989-04-06 1989-04-06 Système de caisse de tête

Country Status (1)

Country Link
EP (1) EP0391015A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1245725A1 (fr) * 2001-03-29 2002-10-02 Andritz AG Procédé et dispositif pour régler des paramètres de qualité d'une machine à papier, tissu ou à égoutter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT363776B (de) * 1980-01-31 1981-08-25 Stroemungsmasch Anst Stoffauflauf fuer siebbandpressen
DE3204740A1 (de) * 1982-02-11 1983-08-18 Escher Wyss Gmbh, 7980 Ravensburg Papiermaschine
DE3439051A1 (de) * 1984-09-19 1986-03-27 Sulzer-Escher Wyss GmbH, 7980 Ravensburg Stoffauflaufvorrichtung fuer eine papiermaschine
GB2201173A (en) * 1987-02-23 1988-08-24 Escher Wyss Gmbh Headbox flow control system
DE3715554A1 (de) * 1987-05-09 1988-12-01 Voith Gmbh J M Anwendung eines verfahrens zum erzielen einer geschwindigkeitsdifferenz eines stoffsuspensionsstrahles sowie papiermaschine zur durchfuehrung des verfahrens

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT363776B (de) * 1980-01-31 1981-08-25 Stroemungsmasch Anst Stoffauflauf fuer siebbandpressen
DE3204740A1 (de) * 1982-02-11 1983-08-18 Escher Wyss Gmbh, 7980 Ravensburg Papiermaschine
DE3439051A1 (de) * 1984-09-19 1986-03-27 Sulzer-Escher Wyss GmbH, 7980 Ravensburg Stoffauflaufvorrichtung fuer eine papiermaschine
GB2201173A (en) * 1987-02-23 1988-08-24 Escher Wyss Gmbh Headbox flow control system
DE3715554A1 (de) * 1987-05-09 1988-12-01 Voith Gmbh J M Anwendung eines verfahrens zum erzielen einer geschwindigkeitsdifferenz eines stoffsuspensionsstrahles sowie papiermaschine zur durchfuehrung des verfahrens

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1245725A1 (fr) * 2001-03-29 2002-10-02 Andritz AG Procédé et dispositif pour régler des paramètres de qualité d'une machine à papier, tissu ou à égoutter

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