EP0275967A2 - Verfahren und Vorrichtung zum Trennen von Knoten - Google Patents
Verfahren und Vorrichtung zum Trennen von Knoten Download PDFInfo
- 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
Links
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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)
- Filtration Of Liquid (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)
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)
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)
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)
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)
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 |
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 |
JPS61207690A (ja) * | 1985-03-12 | 1986-09-16 | 三菱重工業株式会社 | ふるい分け装置 |
-
1987
- 1987-01-19 FI FI870190A patent/FI76139C/fi not_active IP Right Cessation
-
1988
- 1988-01-18 CA CA000556763A patent/CA1329333C/en not_active Expired - Fee Related
- 1988-01-19 DE DE198888100678T patent/DE275967T1/de active Pending
- 1988-01-19 EP EP88100678A patent/EP0275967B1/de not_active Revoked
- 1988-01-19 DE DE8888100678T patent/DE3866116D1/de not_active Revoked
- 1988-01-19 AT AT88100678T patent/ATE69472T1/de not_active IP Right Cessation
- 1988-01-19 JP JP63007648A patent/JPH0696834B2/ja not_active Expired - Fee Related
-
1991
- 1991-07-31 JP JP3191588A patent/JPH0533280A/ja active Pending
Patent Citations (3)
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)
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 |
---|---|
JPH0533280A (ja) | 1993-02-09 |
FI76139B (fi) | 1988-05-31 |
FI870190A0 (fi) | 1987-01-19 |
EP0275967B1 (de) | 1991-11-13 |
DE3866116D1 (de) | 1991-12-19 |
JPS63249792A (ja) | 1988-10-17 |
FI76139C (fi) | 1988-09-09 |
ATE69472T1 (de) | 1991-11-15 |
DE275967T1 (de) | 1989-06-01 |
JPH0696834B2 (ja) | 1994-11-30 |
EP0275967A3 (en) | 1989-02-08 |
CA1329333C (en) | 1994-05-10 |
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