FI61930B - Press release control - Google Patents

Press release control Download PDF

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Publication number
FI61930B
FI61930B FI355472A FI355472A FI61930B FI 61930 B FI61930 B FI 61930B FI 355472 A FI355472 A FI 355472A FI 355472 A FI355472 A FI 355472A FI 61930 B FI61930 B FI 61930B
Authority
FI
Finland
Prior art keywords
fibrous web
pressure
fibrous
belt
web
Prior art date
Application number
FI355472A
Other languages
Finnish (fi)
Other versions
FI61930C (en
Inventor
Leroy Henry Busker
Donald Irving Hoff
Original Assignee
Beloit 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
Priority to US20994171A priority Critical
Priority to US20994171 priority
Application filed by Beloit Corp filed Critical Beloit Corp
Publication of FI61930B publication Critical patent/FI61930B/en
Application granted granted Critical
Publication of FI61930C publication Critical patent/FI61930C/en

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Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00Press section of machines for making continuous webs of paper
    • D21F3/02Wet presses
    • D21F3/0209Wet presses with extended press nip

Description

[B] (11) ^^ RELEASE PUBLICATION,. g, n JRSBTa l ° J 1n | utlAggnINGSSKRIFT Ol!? oU

(+5) ^ (51) Kv.ik.Wo.3 D 21 P 3/02 SUOM I —FI N LAN D (21) Pw * nUlh »k« inu «—P» t * iK * »» 6ki » ln | 355 ^ / 72 (22) HakamtipUv · —Anteknlnc »d« f 15.12.72 (23) Alkupiivt — GifcJ | h «jat | 15.12.72 (41) Interpreters (ulkbaktl - ftllvh offantllg 21 06 73

Patent and Registration Office NihtivUulpro (Fig. ^ Hct ™ date

Patant- och registerstyrelsen '' amMcm uttagd och uti ^ krtfun puMkorad 30.06.82 (32) (33) (31) Pyy * · »r« neikou * —Bogird prior It at 20.12.71 USA (US) 2099 ^ 1 (71 ) Beloit Corporation, Beloit, Wisconsin 53511 »USA (72) Leroy Henry Busker, Rockton, Illinois, Donald Irving Hoff, Beloit,

Wisconsin, USA (US) (7 * 0 Munsterhielm Ky Kb (5 * 0 Adjustable press system - Kontrollerbar pressanordning

The invention relates to improvements in presses for removing water from a continuous, running web, such as a newly formed paper web in a paper machine.

In prior art structures, generally conventional conventional twin-roll wet presses, the rate at which pressure is applied to the web depends primarily on the geometry of the rolls and the speed of the web. High pressures are preferred, but if pressure is applied to the web very rapidly, especially to a finely ground pulp or thick web, rapidly increasing hydraulic pressures within the web may cause the web formation to break. These rapidly increasing hydraulic pressures within the web result in a high local flow rate of water tending to leave the web, and this rupture of the web formation and structure is commonly referred to as "curling." Due to structural limitations, this problem is unavoidable and only minor changes can be made to the roll geometry in practice. When curling occurs, the commonly used solution is to run at a lower speed to reduce the speed at which the necessary compressive force is applied to the web. An alternative way 2 61930 is to reduce the load on the press or to combine the two ways, i. drive at a lower speed and reduce the load on the press. The solution used depends on the overall dewatering capacity of the machine, but both of these solutions reduce the production capacity of the machine.

According to the present invention, a principle is used, which can be called the "long nip" principle, according to which the time during which the web is exposed to the compressive effect is much longer, i. it is provided that the residence time of the web in one press nip is longer than the total time that the web is pressed in several conventional nip press nips. When a single compression delivery is accomplished, re-wetting of the web as it exits several keys in succession and its effects are avoided.

According to the present invention, rapid application of pressure to the inlet side of the nip is avoided, which has hitherto caused the web to break, i.e. to curl. According to the invention, gradual pressure drops on the outlet side of the nip, which tend to cause re-wetting, i.e. return of water to the web.

The object of the present invention is to provide an even better pressing mechanism in which a dewatering pressure is applied to the web at a controlled speed, which makes it possible to adjust the pressure increase in the nip and through it the speed of water leaving the dough when it is pressed.

The invention thus relates to a press device as described in the preamble of the appended claim 1, which is mainly known from the arrangement shown in the characterizing part of the same claim.

Other features of the invention are set out in the subclaims related to the main claim, as well as in the patent specification related to the accompanying patent drawing, in which

Figure 1 is a schematic end view of a press constructed and operative in accordance with the invention,

Fig. 2 is a schematic view similar to Fig. 1 showing a press pressure control arrangement, and

Figure 3 is a diagram showing the pressure profile of the press.

As shown in Figures 1 and 2, the press includes a rotatably mounted support roller 10. The support roller is cylindrical in shape, has a smooth surface, and is rotatably supported by end bearings 10a. It can be forced or rotates due to its contact with the paper web and felt and with belts that can be forced.

3 61930

The paper web enters the press after it is formed in the flat wire portion of the paper machine. In the press, water is pressed from the dough W into the felt F, and suitable drying devices are available to remove moisture from the felt. The paper web then passes on to the drying cylinders and calender to complete the papermaking delivery. It is intended that the present press complete the entire mechanical compression delivery without the need for other presses. Due to the relatively high pressures and the relatively long residence time that can be reached with respect to the paper web in this press, at least as much water can be removed from the dough as is achieved in a standard three-press Puri s-tin section of a paper machine.

The paper web carried by the felt is fed over the surface of the support roll 10, and the web is subjected to a compressive effect in the entire compression zone, starting at 1 * + and extending to 15 at the support roll 10.

The web is pressed against the roll by tensioning belts 11, 12, and 13 which pass over a part of the support roll surface to form a pressing zone IM- 15. In the preferred embodiment, the belts 11, 12 and 13 overlap one another at points which are some distance apart so that the compression pressure increases as each successive belt rests against the support roll lo. The belts are subjected to a relatively high linear tension to produce a compression pressure perpendicular to the roll 10. The press roll is a rigid roll which, of course, bends somewhat due to the forces exerted on it by the belts, but since the belts are flexible, the pressure in the transverse direction of the web remains uniform. When handling relatively wide paper webs, it may be advantageous to provide the roll 10 with a deflection control device to prevent excessive bending. Such a device may be a structure in which the shell of the roll of the press 10 is hollow and through which a stationary shaft is inserted and inside the shell there is a fluid transmission device. The fluid transmission device for transmitting forces to the roll shell on the shaft may be a fluid mass held between the compression zone and the shaft by seals, or a shoe supported by a piston fitted to a cylinder on the shaft, the shoe acting as a plain bearing and lubricated with a lubricating fluid. between the inner surface of the roll shell. Several shoes can be split in the circumferential direction of the roll shell and these can be circumferentially adjustable so that their 1+ 61930 position can be changed as the angle of the roll covered by the straps changes.

As the web V1 passes under the first belt 11 at 1 * +, which is the starting point of the compression zone, it is subjected to a pressure which is a function of the tension of the belt 11. The web is then subjected to a first compressive pressure P-1 as it travels from point 1 to point 16. At point 16, a second belt is placed on top of the first belt, and then the dough is subjected to the combined force of both belts. From point 16 to point 17, a second compressive pressure P-2 is applied to the web. At point 17, the web senses the combined forces of all three belts and is then subjected to a third compression pressure P-3 from point 17 to the end of the compression zone 15. These successive pressures are shown in the diagram in Figure 3. The length of time the web is exposed to each of these pressures depends on the coverage angle.

If the second pressure is to be applied sooner or later, the second belt 12 is caused to settle on the first belt more or later so that the pressure line follows the dashed lines 27b or 27c in Fig. 3 ·

If, on the other hand, the pressure P1 acting in the first part of the zone is desired to be lower, then the tension of the first belt 11 must be loosened, and the curve then follows the line 27a in Fig. 3. If desired, the total pressure can be kept the same simply by increasing the stresses in the uppermost belts 12 and 13.

Thus, excellent flexibility can be achieved with respect to the magnitude and duration of the effective pressure in each of the three parts PI, P2 and P3 (Fig. 1) of the compression zone. As required by webs with different physical properties, it may be necessary to increase the diameter of the press roll to increase the overall length of the press zone. As the length of the zone is increased, the belt tension must be increased to achieve the desired pressure.

The compression fit may be, for example, such that the belt 11 p is tensioned to give a pressure of l1 * kp / cm to the dough and the belt 12 is tensioned to give an additional lh · kp / cm and the belt 13 is tightened to give a pressure of ll · kp / cm. . Thus, the web is subjected to a pressure of 1 kp / cm / cm in the compression zone p o in part P1, 28 kp / cm 'in part P2 and a pressure of 2 kp / cm is applied to the web U-2 in the rest of the compression zone, i.e. in part P3.

The pressures in the zones can be adjusted by adjusting the tension of the belts, and the length of each part of the zone can be adjusted by adjusting the position at which the belts rest on the previous belt.

5,61930

An arrangement to achieve this is shown in Figure 2. In the preferred embodiment, all three belts differ from the dough at the same time, and for this purpose the belts pass over a common turntable 19. The outermost belt is supported by a tensioning roller 20 and extends down over the setting roller 21. The tension roll can be moved by the power device schematically shown in 21a to adjust the belt tension. The position at which the belt 13 rests on the belt 12 is adjusted by moving the setting roller 21 by the device 21a. The tightening device 20a may be hydraulic cylinders or other similar structure. Similarly, the positioning device 21a may be support bearings movable by hydraulic cylinders, and suitable mechanical devices exist to tighten and position all three belts.

The middle belt 12 passes over a tensioning roller 22 which can be moved to tension the belt by a power device 22a. The position at which the belt rests on the lower belt is adjusted by positioning the setting roller 23, which is moved by the power device 23a.

The inner belt, which runs directly on the web, is tightened by a tensioning roller 2k, which can be moved by a power device 2ka.

The position in which the belt 11 rests against the support roller 16 is set by moving the setting roller 25 by the power device 25a.

It may be necessary to make a support on the outer surface of the roll with annular grooves (18, in Figure 2) to facilitate the transfer of water from the dough Vi to the felt F. In some cases, the web may be adapted to pass between the two felts.

Claims (7)

  1. 6 61930
  2. A press device for pressing water from a fibrous web passing through a long pressing zone, consisting of a flexible belt arrangement extending along the pressing zone, applying pressure to the fibrous web (V) and partially supported by a rotating support roll, characterized in that the pressing zone is at least two partly so that the maximum pressure is applied to the fibrous web (W) in the second part (17-15) uniformly in the transverse direction of the fibrous web with lower pressure applied to the fibrous web in said part (17-15) in the direction preceding the fibrous web movement (e.g. 1 * 4-17) , that the hydraulic back pressure in the fibrous web increases at a controlled rate to avoid crushing of the fibrous web.
  3. Device according to claim 1, characterized in that the second part (17-15) of the compression zone (1 * 4-15) has a plurality of belts (11, 12, 13) on top of each other, the lower belt (e.g. 12) extending from the compression zone part (16- 15) through the outermost belt (e.g. 13. extending through only the second part (17-15) of the compression zone so that the force (P-3) acting on the fibrous web (W) in this part is the combined force of the overlapping belts.
  4. Apparatus according to claim 2, characterized in that it has a belt (e.g. 11) which applies a pressure (P-1) to the fibrous web (W) before the start of the other compression zone (16-15). * 4. Device according to Claim 1, 2 or 3, characterized in that the fibrous web (W) is supported against the surface of the cylindrical roll (10) and is located between the lowest belt (11) and the surface of the roll.
  5. Device according to Claim 1, 2 or 3, characterized in that the fibrous web (W) is supported in a manner known per se by a felt (F) receiving water extruded from the fibrous web opposite the surface of the roll (10).
  6. Device according to one of the preceding claims, characterized in that the pressure at the beginning of the compression zone (1 * 4-17) is uniform or adjustable to increase stepwise.
  7. 1. For use in the manufacture of fibrous genomes and in the manufacture of fibrous materials, the use of non-fibrous or non-fibrous materials of the same type as those of the fibrous genome , att presszonen (ιΛ-15) är uppdelad
FI355472A 1971-12-20 1972-12-15 Press release control FI61930C (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US20994171A true 1971-12-20 1971-12-20
US20994171 1971-12-20

Publications (2)

Publication Number Publication Date
FI61930B true FI61930B (en) 1982-06-30
FI61930C FI61930C (en) 1984-06-13

Family

ID=22780964

Family Applications (1)

Application Number Title Priority Date Filing Date
FI355472A FI61930C (en) 1971-12-20 1972-12-15 Press release control

Country Status (3)

Country Link
US (1) US3797384A (en)
FI (1) FI61930C (en)
ZA (1) ZA7208929B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3410172A1 (en) * 1983-03-23 1984-09-27 Valmet Oy Long split press of a paper machine

Families Citing this family (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970515A (en) * 1973-11-05 1976-07-20 Beloit Corporation Controlled sequence pressure nip
US4086131A (en) * 1975-05-06 1978-04-25 Beloit Corporation Method for pressing bagasse webs
US4159947A (en) * 1976-05-17 1979-07-03 Brooks Larry L Dewatering system
JPS5485547A (en) * 1977-12-20 1979-07-07 Ishigaki Mech Ind Method of and device for dehydrating muddy article
US4201624A (en) * 1978-09-05 1980-05-06 Beloit Corporation Extended nip press
FI62692C (en) * 1981-05-20 1983-02-10 Valmet Oy Pappersmaskinspress med bred press
FI68277C (en) * 1983-10-03 1985-08-12 Tamfelt Oy Ab Reference for a reduction of a reduction of a body machinery effect and a press release
JPH0433918B2 (en) * 1984-09-12 1992-06-04 Mitsubishi Heavy Ind Ltd
JPH0429799B2 (en) * 1984-11-15 1992-05-19
US4738752A (en) * 1986-08-12 1988-04-19 Beloit Corporation Heated extended nip press apparatus
US5060299A (en) * 1989-09-29 1991-10-22 Rockwell International Corporation Radio frequency mixer circuit utilizing interface transformers and switching diodes
US5082533A (en) * 1990-04-10 1992-01-21 Beloit Corporation Heated extended nip press with porous roll layers
US5389205A (en) * 1990-11-23 1995-02-14 Valmet Paper Machinery, Inc. Method for dewatering of a paper web by pressing using an extended nip shoe pre-press zone on the forming wire
DE19503767A1 (en) * 1995-02-04 1996-08-08 Voith Sulzer Papiermasch Gmbh Dryer section of a dryer section for sheet material
US7294237B2 (en) * 2004-01-30 2007-11-13 Voith Paper Patent Gmbh Press section and permeable belt in a paper machine
DE102004052157A1 (en) * 2004-10-26 2006-04-27 Voith Fabrics Patent Gmbh Machine for producing a material web
US7476294B2 (en) * 2004-10-26 2009-01-13 Voith Patent Gmbh Press section and permeable belt in a paper machine
US7476293B2 (en) * 2004-10-26 2009-01-13 Voith Patent Gmbh Advanced dewatering system
US7510631B2 (en) * 2004-10-26 2009-03-31 Voith Patent Gmbh Advanced dewatering system
US7527709B2 (en) * 2006-03-14 2009-05-05 Voith Paper Patent Gmbh High tension permeable belt for an ATMOS system and press section of paper machine using the permeable belt
EP1845187A3 (en) 2006-04-14 2013-03-06 Voith Patent GmbH Twin wire former for an atmos system
US7524403B2 (en) * 2006-04-28 2009-04-28 Voith Paper Patent Gmbh Forming fabric and/or tissue molding belt and/or molding belt for use on an ATMOS system
US7550061B2 (en) * 2006-04-28 2009-06-23 Voith Paper Patent Gmbh Dewatering tissue press fabric for an ATMOS system and press section of a paper machine using the dewatering fabric
US20090038174A1 (en) * 2007-08-07 2009-02-12 Dar-Style Consultants & More Ltd. Kitchen utensil dryer

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US645394A (en) * 1899-07-31 1900-03-13 William H Hommel Wine-press.
US2365658A (en) * 1939-06-20 1944-12-19 American Voith Contact Co Inc Apparatus for the removal of water, liquors, or other liquids from soaked masses of fibrous materials
US3110612A (en) * 1960-12-20 1963-11-12 Albemarle Paper Mfg Company Method and apparatus for cast coating paper

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3410172A1 (en) * 1983-03-23 1984-09-27 Valmet Oy Long split press of a paper machine
DE3410172C2 (en) * 1983-03-23 1995-11-09 Valmet Paper Machinery Inc Long nip press of a paper machine

Also Published As

Publication number Publication date
FI61930C (en) 1984-06-13
ZA7208929B (en) 1973-09-26
US3797384A (en) 1974-03-19

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