EP0275967A2 - Verfahren und Vorrichtung zum Trennen von Knoten - Google Patents

Verfahren und Vorrichtung zum Trennen von Knoten Download PDF

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Publication number
EP0275967A2
EP0275967A2 EP88100678A EP88100678A EP0275967A2 EP 0275967 A2 EP0275967 A2 EP 0275967A2 EP 88100678 A EP88100678 A EP 88100678A EP 88100678 A EP88100678 A EP 88100678A EP 0275967 A2 EP0275967 A2 EP 0275967A2
Authority
EP
European Patent Office
Prior art keywords
cylinder
reject
pulp
ridges
rized
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.)
Granted
Application number
EP88100678A
Other languages
English (en)
French (fr)
Other versions
EP0275967A3 (en
EP0275967B1 (de
Inventor
Kaj Henricson
Erkki Repo
Hannu Rönkönharju
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.)
Ahlstrom Corp
Original Assignee
Ahlstrom Corp
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
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First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=8523793&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0275967(A2) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Ahlstrom Corp filed Critical Ahlstrom Corp
Priority to AT88100678T priority Critical patent/ATE69472T1/de
Publication of EP0275967A2 publication Critical patent/EP0275967A2/de
Publication of EP0275967A3 publication Critical patent/EP0275967A3/en
Application granted granted Critical
Publication of EP0275967B1 publication Critical patent/EP0275967B1/de
Anticipated expiration legal-status Critical
Revoked legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D5/00—Purification of the pulp suspension by mechanical means; Apparatus therefor
    • D21D5/02—Straining or screening the pulp
    • D21D5/06—Rotary screen-drums

Definitions

  • the present invention relates to a method and apparatus for separating knots.
  • the method and apparatus are in particular suitable in separating knots from high consistency pulp.
  • a third arrangement is described in the US patent publication 4,441,999 which consists of a cylindrical outer casing and a rotating screen cylinder. Inside the screen cylinder there are one or more stationary non-rotating blades. The pulp is tangentially fed between the screen cylinder and the outer casing, but the opposite to the direction of rotation of the cylinder. The accept is dis­charged from the inside of the screen cylinder at the end of the cylinder and the reject tangentially, but opposite to the direction of rotation of the cylinder.
  • the screen cylinder consists of openings that open to the inside of the cylinder and of connecting pieces which in principle consist of radial arms and parts bent forward to the direction of the pulp flow coming to the cylinder which produce pressure pulses to the pulp to keep the holes of the screen cylinder open.
  • the apparatus in accordance with this publication was found to operate especially well in paper machine short circulation and equivalent where it enabled the dampening of the fluctuation of the pressure inconvenient to further processing.
  • the latter two devices are characterized in that they reach the consistency range of 4 - 6 %, whereas the device according to the first example functions only in the consistency of up to 1,5 - 2 %. Plugging of the holes on the screen surface limits the operation in all devices. Yet, in stock processing the aim is consistently towards higher consistencies, because it is in every respect more preferable to tend to treat the pulp in different process stages in the same consistency without thickening and dilution. If it is possible to raise the processing consistency, savings can be gained in both device and transportation charges and also considerably in the consumption of energy.
  • the object of the present invention is to provide an improved method and apparatus for separating knots which reaches the so called low range of the MC-consistency (6 - 8 %) and diminishes significantly of the consumption of energy.
  • the rise of the applicable range of consistency is achieved by the correct measuring and formulation of the screen profile, and optimizing the rotational speed of the cylinder with respect to the feeding speed of the pulp.
  • the consumption of energy of the knotter of the present invention has been measured to have been at most 0,6 kWh/ mass ton. Furthermore the change of the direction of rotation has diminished the wear of the screen cylinder.
  • an apparatus in accordance with the present invention is facilitation of reject outlet com­pared to the approach in accordance with the US patent 4,441,999, because in the apparatus according to the present invention the reject is discharged in the direction of the rotation of the screen cylinder.
  • This pumping effect together with dilution water led to the reject in the discharge stage significantly facilitates the adjustment of the amount of reject.
  • the reject rate can be maintained between 2 to 10 % by using the screen in accordance with the present invention.
  • the method according to the present invention is among other things characterized in that the fibre suspension is tangen­tially introduced in the direction of rotation of the screen cylinder and the reject is discharged tangentially in the direction of rotation of the screen cylinder.
  • the apparatus according to the invention is characte­rized in that the direction of rotation of the cylinder is parallel to direction of pulp feed from the inlet connection, the direction of the outlet of the reject from the outlet connection is the same as the direction of rotation of the cylinder and that the cylinder is contoured in the way that on the outer surface of the cylinder there are ridges between the openings.
  • the blades 6 are attached with arms 13 and 14 to a stationary frame 15 which also forms a strut for the shaft 7 through the bearing 16.
  • the blades 6 are positioned in the cylinder 5 so that the blade situated near the reject connection 4 is ⁇ 10 - 45° aside from it.
  • the other blade is 10 - 45° aside from the input connection 2.
  • the above men­tioned blades generate the applicable pulse, positive and/or negative, to the cylinder 5.
  • the contoured plate 20 consists of openings 21 and of lands 22 between them.
  • Plate 20 is plain on the inner surface 23 excluding the openings.
  • the outer surface of the plate 20 consists of front surfaces 25 rising at a certain angle from the plane 24 of the plate 20, substantially of the surfaces 26 parallel to the plane 24 of the plate 20, substantially of the end surfaces 27 upright to the plane 24 of the plate 20 and of parts 28 of the plane 24 between the openings 21.
  • the screen plate can be considered to consist of a plate which has ridges 29 which consist of the above mentioned parts 25, 26 and 27, and of the plane like parts 28 between them, in which the openings 21 are machined.
  • the openings 21 are preferably holes (or slots) the diameter of which can range depending on the application at least between 5- 15 mm. It also appears in Fig. 4 that the ridges 29 can be slightly declined from the axial direction of the plate. From the declination angle of the ridges, the direction of the declination in respect to the direction of rotation, the speed of rotation and the ascending angle of the part 25 of the ridges the circulation time of the pulp in the knotter can be optimized in relation with the result of the separation.
  • the circumferential speed of the cylinder used in the performed tests has been 4 - 10 m/s and for the feed of the pulp 2 m/s in the performed experiments.
  • the speed difference between the cylinder and the pulp is 2 - 8 m/s.
  • the gradient plane 25 of the ridges 29 of the screen plate 20 receives the pulp coming into the cylin­der, tending to accelerate its speed.
  • the direction of the ridges 29 has the effect that if the ridges 29 on the screen cylinder 5 are backwards inclined, they tend to raise the pulp upwards in the cylinder, thereby the circulation time of the pulp in the knotter becomes longer, the separation takes place more accurately and the amount of reject diminishes while the amount of accept grows.
  • the circulation time becomes shorter and the separation is not so accurate.
  • the height of the screen cylinder effects the speed, inclination angles, etc. used.
  • the method and apparatus in accordance with the present invention function in the following way.
  • the pulp is tangen­tially fed by pressure into the space between the rotating screen cylinder and the outer housing of the knotter and in the same direction as the rotating motion of the screen.
  • the ridges of the screen cylinder subject the infed pulp to circumferential forces for increasing its speed of motion and, due to the shape of the ridges, also shear forces for opening the bonds between the pulp particles, i.e. the fibres.
  • the ridges cause at the outlet end in front of the surface 27 a low pressure zone that attracts the loose fibres through openings 21 with the help of the pressure difference between the inlet connections 2 and the accept connections 3.
  • the heavier particles carried by the pulp sling towards the surface of the housing 1 when hitting the ridges, whereby they are also subjected to the centrifugal force.
  • the lighter particles of the pulp are enriched near the surface of the screen cylinder and are separated from the pulp in the above mentioned way. Due to the contours of the surface of the cylinder a slight fluidization takes place near the surface of the screen cylinder, helping the separation and on the other hand also diminishing the consumption of energy of the sepa­ration and the wear of the screen cylinder.
  • the heavy par­ticles separated onto the surface of the outer housing of the knotter circulate down the housing surface along the spiral path and are tangentially discharged from the knotter through the connection 4. The discharge is activated more by feeding, if necessary, dilution water to the reject from the pipe 11.
  • the apparatus in accordance with the invention described above has made it possible to diminish the consumption of energy in respect to the prior art more than 30 % and at the same time it has been possible to in­crease the consistency of the pulp up to the lower range of the MC-consistency.
  • a less wearing screen cylinder and an apparatus better adjustable in its function and in its end products has also been brought about. For example, merely changing the rotational speed of the cylinder it is possible to adjust the apparatus applicable to most dif­ferent consistencies and different kinds of pulps.
  • this method is added by a possibility to produce screen cylinders having varying inclination angles of ridges or openings of variable sizes, one is able to talk about an ultimately optimized knotter.
  • a knotter according to the present invention may in reality differ a lot from the form shown above and yet not differ from the inventive idea which is more closely described in the accompanying claims. It is namely quite possible that in some cases it is necessary to use an inclination angle of two or more ridges or that the speeds of the pulp suspension and the cylinder differ a lot from the example shown above, substantial is, however, only the difference of the speeds which according to the claims is 2-8 m/s.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Control And Other Processes For Unpacking Of Materials (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Medicines Containing Material From Animals Or Micro-Organisms (AREA)
  • Separation Of Solids By Using Liquids Or Pneumatic Power (AREA)
EP88100678A 1987-01-19 1988-01-19 Verfahren und Vorrichtung zum Trennen von Knoten Revoked EP0275967B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88100678T ATE69472T1 (de) 1987-01-19 1988-01-19 Verfahren und vorrichtung zum trennen von knoten.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI870190 1987-01-19
FI870190A FI76139C (fi) 1987-01-19 1987-01-19 Foerfarande och anordning foer kvistseparering.

Publications (3)

Publication Number Publication Date
EP0275967A2 true EP0275967A2 (de) 1988-07-27
EP0275967A3 EP0275967A3 (en) 1989-02-08
EP0275967B1 EP0275967B1 (de) 1991-11-13

Family

ID=8523793

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88100678A Revoked EP0275967B1 (de) 1987-01-19 1988-01-19 Verfahren und Vorrichtung zum Trennen von Knoten

Country Status (6)

Country Link
EP (1) EP0275967B1 (de)
JP (2) JPH0696834B2 (de)
AT (1) ATE69472T1 (de)
CA (1) CA1329333C (de)
DE (2) DE275967T1 (de)
FI (1) FI76139C (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000053845A1 (en) * 1999-03-10 2000-09-14 Valmet Fibertech Ab Screening apparatus
US6254729B1 (en) 1999-03-22 2001-07-03 Voith Sulzer Paper Technology North America, Inc. Pulper with extraction plate assembly having removable inserts and method of manufacturing same
WO2011004060A1 (en) * 2009-07-07 2011-01-13 Andritz Oy Apparatus for screening fibre suspensions

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4308225C1 (de) * 1993-03-16 1994-11-24 Escher Wyss Gmbh Verfahren zur Sortierung von Faserstoffsuspension sowie Siebvorrichtung zu seiner Durchführung
JP4909693B2 (ja) * 2006-07-24 2012-04-04 相川鉄工株式会社 スクリーン装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE316363B (de) 1966-12-01 1969-10-20 Karlstad Mekaniska Ab
US3947314A (en) 1974-04-29 1976-03-30 The Black Clawson Company Method of treating paper fibers in a stationary screen
US4441999A (en) 1980-01-28 1984-04-10 Ab Celleco Strainer means for pulp purification

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH182068A (de) * 1935-03-21 1936-01-31 Miag Muehlenbau & Ind Ag Sichter für faserhaltiges Gut, insbesondere für Stoffe zur Papierherstellung.
SE315479B (de) * 1963-10-21 1969-09-29 Knutsilplatar Malm N Ab
US3363759A (en) * 1964-04-29 1968-01-16 Bird Machine Co Screening apparatus with rotary pulsing member
DE1905832U (de) * 1964-09-16 1964-12-03 Hermann Finckh G M B H Sichter fuer papierstoff-suspensionen.
SE374148B (de) * 1972-08-31 1975-02-24 S E E Ahlfors
US4017387A (en) * 1975-08-11 1977-04-12 The Black Clawson Company Screening apparatus
SE426958B (sv) * 1980-02-25 1983-02-21 Celleco Ab Separator for uppdelning av en inkommande blandning av cellulosasuspension eller liknande och grova tunga partiklar
WO1986003688A1 (en) * 1984-12-25 1986-07-03 Mitsubishi Jukogyo Kabushiki Kaisha Pressure slit screen
JPS61207690A (ja) * 1985-03-12 1986-09-16 三菱重工業株式会社 ふるい分け装置
JPS61207689A (ja) * 1985-03-12 1986-09-16 三菱重工業株式会社 ふるい分け装置
JPS61207069A (ja) * 1985-03-12 1986-09-13 Nec Corp 半導体装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE316363B (de) 1966-12-01 1969-10-20 Karlstad Mekaniska Ab
US3947314A (en) 1974-04-29 1976-03-30 The Black Clawson Company Method of treating paper fibers in a stationary screen
US4441999A (en) 1980-01-28 1984-04-10 Ab Celleco Strainer means for pulp purification

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000053845A1 (en) * 1999-03-10 2000-09-14 Valmet Fibertech Ab Screening apparatus
US6254729B1 (en) 1999-03-22 2001-07-03 Voith Sulzer Paper Technology North America, Inc. Pulper with extraction plate assembly having removable inserts and method of manufacturing same
US6623572B2 (en) 1999-03-22 2003-09-23 Voith Sulzer Paper Technology North America, Inc. Pulper with extraction plate assembly having removable inserts and method of manufacturing same
WO2011004060A1 (en) * 2009-07-07 2011-01-13 Andritz Oy Apparatus for screening fibre suspensions
CN102472008A (zh) * 2009-07-07 2012-05-23 安德里兹公司 用于筛选纤维悬浮液的设备

Also Published As

Publication number Publication date
FI76139C (fi) 1988-09-09
ATE69472T1 (de) 1991-11-15
CA1329333C (en) 1994-05-10
EP0275967A3 (en) 1989-02-08
DE275967T1 (de) 1989-06-01
FI76139B (fi) 1988-05-31
FI870190A0 (fi) 1987-01-19
JPS63249792A (ja) 1988-10-17
DE3866116D1 (de) 1991-12-19
JPH0533280A (ja) 1993-02-09
EP0275967B1 (de) 1991-11-13
JPH0696834B2 (ja) 1994-11-30

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