EP0105975B1 - Procédé pour l'élimination du condensat d'un cylindre, en particulier d'un cylindre pour le séchage du papier - Google Patents

Procédé pour l'élimination du condensat d'un cylindre, en particulier d'un cylindre pour le séchage du papier Download PDF

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Publication number
EP0105975B1
EP0105975B1 EP82201286A EP82201286A EP0105975B1 EP 0105975 B1 EP0105975 B1 EP 0105975B1 EP 82201286 A EP82201286 A EP 82201286A EP 82201286 A EP82201286 A EP 82201286A EP 0105975 B1 EP0105975 B1 EP 0105975B1
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EP
European Patent Office
Prior art keywords
cylinder
valve
conduit
steam
degree
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.)
Expired
Application number
EP82201286A
Other languages
German (de)
English (en)
Other versions
EP0105975A1 (fr
Inventor
Rudi Van Os
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.)
KNP LEYKAM SERVICES BV
Nv Koninklijke Knp Bt nv Koninklijke Knp
Original Assignee
Koninklijke Nederlandsche Papierfabriek NV
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 Koninklijke Nederlandsche Papierfabriek NV filed Critical Koninklijke Nederlandsche Papierfabriek NV
Priority to AT82201286T priority Critical patent/ATE17879T1/de
Priority to DE8282201286T priority patent/DE3268994D1/de
Priority to EP82201286A priority patent/EP0105975B1/fr
Publication of EP0105975A1 publication Critical patent/EP0105975A1/fr
Application granted granted Critical
Publication of EP0105975B1 publication Critical patent/EP0105975B1/fr
Expired 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
    • D21F5/00—Dryer section of machines for making continuous webs of paper
    • D21F5/02—Drying on cylinders
    • D21F5/022—Heating the cylinders
    • D21F5/028—Heating the cylinders using steam
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F5/00—Dryer section of machines for making continuous webs of paper
    • D21F5/02—Drying on cylinders
    • D21F5/10—Removing condensate from the interior of the cylinders

Definitions

  • This invention relates to a method for the removal of condensate from a cylinder, in particular a cylinder for drying paper, to which cylinder a fluid under pressure is supplied via a first conduit, and with which cylinder means are coupled for the removal of this fluid via a second conduit, a source of steam being coupled via a first controllable valve with the fluid supply conduit, the fluid in the discharge conduit of the cylinder being separated into a gaseous component and a liquid component, and the quantity of the gaseous component being measured and kept constant by control means (US-A-2869248).
  • a water/paper mixture for example having a water-to-paper ratio of 200:1 is processed in successive stages to withdraw an ever larger quantity of water.
  • the semi-dry mixture is subsequently passed in a broad ribbon over a plurality of rotating drying cylinders. These cylinders are hollow and closed at the sides.
  • steam is supplied to the interior of each cylinder as a drying fluid, which steam transfers heat to the paper web via the cylinder wall.
  • the condensate must be removed from the cylinder, because a layer of condensate within the cylinder adversely affects the transfer of heat from the steam to the cylinder wall, and when not removed, the cylinder ultimately becomes full of water.
  • the condensate is not only present on the bottom of the cylinder, but a layer of condensate is formed throughout the entire inner circumference of the cylinder.
  • a syphon in the cylinder which may be stationary, or adapted to rotate.
  • the syphon inlet is positioned within the cylinder spaced a small distance from the cylinder wall, and the syphon outlet is disposed adjacent to the longitudinal axis of the cylinder.
  • US-A-2,869,248 describes a method for removing condensate from a cylinder for drying paper wherein the fluid in the discharge conduit is separated into a gaseous component and a liquid component and wherein the quantity of the gaseous component is measured and kept constant.
  • This known method aims to keep the amount of steam minimal, when no or only a little quantity of condensate has to be removed and at a maximum when a large quantity of steam has to be removed.
  • the known method therefore provide a drying of paper with a relatively small loss of energy.
  • the aim is for an increase in rotary speed of the cylinders, which increase in velocity results in an increase in centrifugal force, on the condensate in the cylinder and hence in rendering the required steam minimum pressure for the removal of the condensate very high.
  • the required minimum pressure and the associated temperature in the cylinder are increased to such an extent as to render impossible a proper control of the moisture evaporation process, which is necessary for making high- quality paper.
  • it is desired for the rate of evaporation to be decreased it is inevitable to tolerate a certain quantity of condensate in the cylinders.
  • This layer of condensate decreases the amount of heat that the steam delivers to the paper web. Of course such a layer of condensate not only causes an unnecessary and unwanted loss of energy but also requires more power for rotating the cylinder.
  • the present invention provides a method of the above kind in which a source of compressed air is coupled via a second controllable valve also to said fluid supply conduit, the arrangement being such that when the measured quantity of gaseous component is too low, this is controlled in the first instance by controlling the degree of opening of said first valve and in the second instance, when said first valve has been opened to a pre-determined position, by controlling the degree of opening of said second valve, and when the measured quantity of gaseous component is too large, in the first instance the degree of opening of the second valve is controlled and in the second instance, when said second valve is fully closed, the degree of opening of said valve is controlled.
  • One advantage of the method according to the invention is that the amount of energy required for drying the paper may be minimal, because it is always ensured that there is a very thin layer of condensate on the inside of the cylinder, and only a minimal quantity of steam together with a certain amount of compressed air is used to maintain the required quantity of gas.
  • Another advantage is that the drive for rotating the cylinders needs to be of less heavy construction than with the prior method.
  • steam is supplied via a conduit 2 from a souce of steam 3.
  • the quantity of steam can be adjusted by means of a controllable valve 4.
  • the gas is supplied via a conduit 11 to an orifice plate 12, by means of which the quantity of gas flowing through it can be determined by means of the pressure difference measured.
  • the gas is subsequently also supplied to receptacle 10 via conduit 13. Further connected to this receptacle are a further conduit 14 for the removal of gas under low pressure, and a conduit 15 for the discharge of condensate.
  • the pressure in receptacle 10 must be selected at least so much lower than the pressure in steam supply conduit 2 that the velocity of the steam in the valve is critical. At a critical steam velocity through valve 4, there is a unique relationship between the adjusted position of the valve and the amount of steam passed.
  • the pressure difference of the gas flowing through orifice plate 12 is converted in measuring device 16 into a certain air pressure.
  • This air pressure is passed via conduit 17 to a control device 18.
  • Control device 18 can ensure that the pressure difference across orifice plate 12 is maintained at a pre-determined, constant value by controlling the supply of gas to the drying cylinder. In this way it is possible to keep the gas flow velocity in syphon 5 constant at a pre-determined value independent of the amount of condensate.
  • Control device 18 gives via conduit 19 a control air pressure signal to the controllable valves 21 and 4 for the supply of gas.
  • This signal varies in a certain range, e.g. from 1 to 2 bar.
  • control device 18 finds that there is an insufficient pressure difference across orifice plate 12, and increases the controlling air pressure to conduit 19.
  • a second kind of gas which cannot be condensed such as compressed air, is supplied from a source of compressed air 20 via controllable valve 21 and conduit 22.
  • valve 21 At the maximum controlling pressure, valve 21 is in the fully open position, and at approximately half the value of the controlling air pressure range, it is fully closed.
  • control device 18 As the steam and air flow into the cylinder, heat transfer by the steam will be decreased, and a mixture of steam and air will flow through the orifice plate. If control device 18 now finds that the adjusted threshold value of the pressure difference across orifice plate 12 is exceeded, it decreases the control pressure in conduit 19 to such an extent that via valve 21 for the compressed air an equilibrium is reached.
  • control device 18 will find that the pressure difference across orifice plate 12 is too high, while the valve for the compressed air is already closed. In that case the controlling air pressure in conduit 19 is decreased to below approximately half the value of the control pressure range.
  • Conduit 19 is connected via a relay 23 to valve 4.
  • Relay 23 operates as follows: If control pressures of four different levels are supplied, only the lowest level is passed to valve 4, and the others are ignored. In the embodiment shown, control valve 4 is open at a control pressure approximately halfway the control pressure range, and closed at the minimum control pressure.
  • relay 23 may have three other functions:
  • the great advantage of the method according to the invention is that the amount of steam supplied to the cylinders can be very accurately controlled, and limited to a minimal quantity without the occurrence of any problems with regard to the flooding of the cylinder with condensate, but the method also permits an accurate control of the amount of heat given up to the paper web, and minimizes loss in energy. In addition, by controlling the amount of compressed air supplied, optimal de-watering with a minimal amount of energy is possible.
  • control system such as receptacle and source of steam for a plurality of cylinders, but in any case it is necessary for every cylinder to have its own separator, orifice plate and control circuit.

Landscapes

  • Paper (AREA)
  • Drying Of Solid Materials (AREA)

Claims (4)

1. Procédé d'extraction du condensat présent dans un cylindre, en particulier un cylindre sécheur de papier, dans lequel cylindre (1) un fluide sous pression est admis par un premier conduit (2) et avec lequel des moyens (5) sont couplés pour l'extraction du fluide par un second conduit (6), une source (3) de vapeur étant raccordée, par l'intermédiaire d'une valve commandée (4), au conduit d'admission (2), le composant gazeux et le composant liquide du fluide dans le conduit d'extraction (6) du cylindre (1) étant séparés, et la quantité du composant gazeux étant mesurée et maintenue constante par des moyens de régulation (18), caractérisé en ce qu'une source (20) d'air comprimé est également raccordée, au travers d'une seconde valve commandée (21) audit conduit d'admission (2), dans un arrangement tel que, lorsque la quantité mesurée du composant gazeux est trop faible, elle est régulée dans un premier cas en agissant sur le degré d'ouverture de ladite première valve (4) et dans un deuxième cas, si ladite première valve (4) a été ouverte à une position prédéterminée, en agissant sur le degré d'ouverture de ladite seconde valve (21), et lorsque la quantité mesurée du composant gazeux est trop importante, dans un premier cas, le degré d'ouverture de ladite seconde valve (21) est commandé et dans un second cas, si ladite seconde valve (21) est complètement fermée, le degré d'ouverture de ladite première valve (4) est commandé.
2. Procédé selon la revendication 1 caractérisé en ce que le degré d'ouverture de la première valve est également commandé par une valve (24) de réduction par laquelle la quantité maximale de vapeur admise dans le cylindre (1) est ajustée.
3. Procédé selon la revendication 1 ou la revendication 2, caractérisé en ce qu'un premier signal de commande (26) est délivré à ladite première valve (4) lorsqu'il se produit une rupture de le bande de papier en train de sécher, et en ce qu'un second signal de commande (25) est délivré à ladite première valve (4) lorsque le montant d'humidité dans le papier est considéré comme anormal.
4. Procédé selon la revendication 3, caractérisé en ce que le signal de commande (18, 24, 25, 26) des moyens de commande de la première valve (4) qui a la valeur la plus basse, détermine le degré d'ouverture de la première valve (4).
EP82201286A 1982-10-14 1982-10-14 Procédé pour l'élimination du condensat d'un cylindre, en particulier d'un cylindre pour le séchage du papier Expired EP0105975B1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AT82201286T ATE17879T1 (de) 1982-10-14 1982-10-14 Verfahren zum abfuehren des kondensates aus einem zylinder, insbesondere einem zylinder zum trocknen von papier.
DE8282201286T DE3268994D1 (en) 1982-10-14 1982-10-14 A method for removing condensate from a cylinder, in particular a cylinder for drying paper
EP82201286A EP0105975B1 (fr) 1982-10-14 1982-10-14 Procédé pour l'élimination du condensat d'un cylindre, en particulier d'un cylindre pour le séchage du papier

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP82201286A EP0105975B1 (fr) 1982-10-14 1982-10-14 Procédé pour l'élimination du condensat d'un cylindre, en particulier d'un cylindre pour le séchage du papier

Publications (2)

Publication Number Publication Date
EP0105975A1 EP0105975A1 (fr) 1984-04-25
EP0105975B1 true EP0105975B1 (fr) 1986-02-05

Family

ID=8189523

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82201286A Expired EP0105975B1 (fr) 1982-10-14 1982-10-14 Procédé pour l'élimination du condensat d'un cylindre, en particulier d'un cylindre pour le séchage du papier

Country Status (3)

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EP (1) EP0105975B1 (fr)
AT (1) ATE17879T1 (fr)
DE (1) DE3268994D1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19534571C2 (de) * 1995-09-18 2001-06-28 Voith Sulzer Papiermasch Gmbh Vorrichtung für eine Papiermaschine zur Förderung von Flüssigkeit von einem ersten Niveau auf ein zweites, höheres Niveau
EP1742404B1 (fr) 2005-07-04 2009-04-01 Nokia Siemens Networks Gmbh & Co. Kg Procédé et appareil d'adaptation de données à une unité de transport de taille prédéterminée, avant transmission
CN102392383A (zh) * 2011-10-31 2012-03-28 李永华 一种基于尾气流量检测的蒸汽冷凝水热泵系统
CN109653018A (zh) * 2019-01-28 2019-04-19 湖南南杰电材科技有限公司 一种云母纸烘缸组件

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2102106A (en) * 1936-10-21 1937-12-14 William S Allen Apparatus for discharging condensate from drying drums
US2291131A (en) * 1940-08-19 1942-07-28 Arnstrong Machine Works Temperature control for driers and other heat exchange elements
US2869248A (en) * 1955-10-17 1959-01-20 Beloit Iron Works Condensate removal control for paper machine dryers
US2992493A (en) * 1958-04-16 1961-07-18 Worthington Corp Method and apparatus for controlling and limiting the quantity of "blowthru" steam in a drying system
US4222178A (en) * 1979-07-16 1980-09-16 Midland-Ross Corporation Method and apparatus for controlling a drying cylinder

Also Published As

Publication number Publication date
ATE17879T1 (de) 1986-02-15
DE3268994D1 (en) 1986-03-20
EP0105975A1 (fr) 1984-04-25

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