US3800357A - Doctor device for paper making machine - Google Patents

Doctor device for paper making machine Download PDF

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Publication number
US3800357A
US3800357A US00205165A US20516571A US3800357A US 3800357 A US3800357 A US 3800357A US 00205165 A US00205165 A US 00205165A US 20516571 A US20516571 A US 20516571A US 3800357 A US3800357 A US 3800357A
Authority
US
United States
Prior art keywords
blade
arm
doctor device
making machine
paper making
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 - Lifetime
Application number
US00205165A
Other languages
English (en)
Inventor
O Skytta
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.)
Valmet Montreal Inc
Original Assignee
Valmet Oy
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 Valmet Oy filed Critical Valmet Oy
Application granted granted Critical
Publication of US3800357A publication Critical patent/US3800357A/en
Assigned to VALMET-DOMINION INC., A COMPANY OF CANADA reassignment VALMET-DOMINION INC., A COMPANY OF CANADA ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: VALMET OY
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G3/00—Doctors
    • D21G3/005—Doctor knifes

Definitions

  • doctor devices are used, for instance, in the calenders and presses of the paper making machine.
  • the blade pressure of the blade against the roll has to be made at least nearly constant over the entire length of the roll.
  • existing doctor devices the required blade pressure between the roll and the blade was produced by the weight of the doctor device. In such doctor devices the blade pressure could be made to be sufficiently constant over the entire length of the roll.
  • doctor devices have the drawback that achievement of sufficiently high blade pressures was difficult and in some cases even impossible. It has therefore become quite common practice to use doctor devices in which at the ends of their bodies there are hydraulically or pneumatically operating swivelling cylinders for producing required blade pressure. It is true that in doctor devices of this kind blade pressures of desired magnitude are achieved, but when conventional doctor devices are used, the blade pressure at the ends will be higher than at the center, and the device does not operate satisfactorily. In order to eliminate this drawback it has been necessary to install in the body of the doctor device, devices for the compensation of deflection. However, such devices render the construction of the doctor device complex and expensive.
  • the blade to a supporting arm consisting of an elastic plate and having a length equal to that of the blade.
  • the arm is fixed to the rear end of the side of the body beam facing its swivelling direction and so that it is located outside this side; this side of the body beam is convexly curved, extending away from the supporting arm in the direction towards the blade.
  • a protection plate having the same length as the blade and resting elastically against the outer surface of the side of the body beam constituting its rear side with reference to the swivelling direction of the beam, thereby enclosing the space between said plate-like supporting arm and the body beam.
  • the body beam which most appropriately has a drop-shaped cross section, is pivotally supported at its ends, at the centroid of its cross sec tion. In that case the influence of the operational position of the doctor device on the blade pressure is eliminated, because then the blade pressure is solely dependent on the load imposed by the swivelling cylinders. Machining of the outer surface of the body to have desired shape and straightness is made easier.
  • journal pins are connected to swivelling cylinders at the ends of the doctor device.
  • the blade pressure is then solely dependent on the load imposed by the swivelling cylinders.
  • the arrow a indicates the swivelling direction of the doctor device.
  • the blade 5 of the doctor device is connected by the blade holder 6 to a supporting arm 7 consisting of elastic sheet material and having the same length as the blade 5.
  • the end of the arm opposite to the end where the blade has been fitted, is attached to the rear end of that side 8 of the body beam 1 which faces the swivelling direction, by means of the screw 9 and the counterpiece 10.
  • the side 8 is convexly curved.
  • the supporting arm 7 located outside the side 8 draws farther away from the side 8 in the direction towards the blade 5.
  • the supporting arm 7 has a breadth such that the blade 5 will be positioned farther in frontal direction than the front end of the body beam 1.
  • an elastie protective plate 11 has been attached, the curved end of which presses against the upper side of the body beam 1.
  • the protective plate 11 has the length of the blade 5, so that it encloses the space between the supporting arm 7 and the side 8 of the body beam 1, preventing entrance of pulp or of other foreign matter into this space.
  • the supporting arm 7 bends to be closer to the side 8.
  • the point of contact between the supporting arm 7 and the side 8 moves closer to the blade. Since the side 8 is curved, this point of contact may move steplessly.
  • the flexural rigidity of the supporting arm will always be the same over the entire blade length.
  • the spacing of the supporting arm becomes shorter, so that the stress imposed on the supporting arm and its elastic yielding remain within reasonable limits.

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  • Paper (AREA)
US00205165A 1970-12-09 1971-12-06 Doctor device for paper making machine Expired - Lifetime US3800357A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FI703321A FI45127C (sv) 1970-12-09 1970-12-09 Skavaranordning för pappersmaskin.

Publications (1)

Publication Number Publication Date
US3800357A true US3800357A (en) 1974-04-02

Family

ID=8508280

Family Applications (1)

Application Number Title Priority Date Filing Date
US00205165A Expired - Lifetime US3800357A (en) 1970-12-09 1971-12-06 Doctor device for paper making machine

Country Status (3)

Country Link
US (1) US3800357A (sv)
CA (1) CA953962A (sv)
FI (1) FI45127C (sv)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4038919A (en) * 1975-02-25 1977-08-02 Societe Alsacienne De Constructions Mecaniques De Mulhouse Doctor blade holders for screen process printing machines
DE4141133C1 (en) * 1991-12-13 1993-05-27 J.M. Voith Gmbh, 7920 Heidenheim, De Support beam for doctor blade bearing on dry cylinder - comprises elongated hollow body having 2 or more convex curved longitudinal walls and composed of composite fibre material e.g. carbon@ fibres
US6749725B1 (en) * 1999-10-06 2004-06-15 Metso Paper, Inc. Blade holder for a doctor and a method for using the doctor
US20050087318A1 (en) * 2003-09-16 2005-04-28 Christian Corriveau Blade holding device, assembly including the same, and method of operating associated thereto

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1797290A (en) * 1928-12-10 1931-03-24 Black Clawson Co Paper-making machinery
US2191366A (en) * 1938-01-15 1940-02-20 Buccicone Dario Roll scraper
CH298519A (de) * 1950-12-22 1954-05-15 Vickerys Ltd Walzen-Schabervorrichtung.
US3121904A (en) * 1961-04-07 1964-02-25 Vickerys Ltd Doctors for paper making machines

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1797290A (en) * 1928-12-10 1931-03-24 Black Clawson Co Paper-making machinery
US2191366A (en) * 1938-01-15 1940-02-20 Buccicone Dario Roll scraper
CH298519A (de) * 1950-12-22 1954-05-15 Vickerys Ltd Walzen-Schabervorrichtung.
US3121904A (en) * 1961-04-07 1964-02-25 Vickerys Ltd Doctors for paper making machines

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4038919A (en) * 1975-02-25 1977-08-02 Societe Alsacienne De Constructions Mecaniques De Mulhouse Doctor blade holders for screen process printing machines
DE4141133C1 (en) * 1991-12-13 1993-05-27 J.M. Voith Gmbh, 7920 Heidenheim, De Support beam for doctor blade bearing on dry cylinder - comprises elongated hollow body having 2 or more convex curved longitudinal walls and composed of composite fibre material e.g. carbon@ fibres
FR2685436A1 (fr) * 1991-12-13 1993-06-25 Voith Gmbh Sommier pour un element de travail, tel qu'une lame de racloir, pour la fabrication de bandes de matieres fibreuses.
US5356519A (en) * 1991-12-13 1994-10-18 J.M. Voith Gmbh Support beam made of composite fiber material
US6749725B1 (en) * 1999-10-06 2004-06-15 Metso Paper, Inc. Blade holder for a doctor and a method for using the doctor
US20050087318A1 (en) * 2003-09-16 2005-04-28 Christian Corriveau Blade holding device, assembly including the same, and method of operating associated thereto

Also Published As

Publication number Publication date
FI45127B (sv) 1971-11-30
CA953962A (en) 1974-09-03
FI45127C (sv) 1972-03-10

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Legal Events

Date Code Title Description
AS Assignment

Owner name: VALMET-DOMINION INC., 795 FIRST AVENUE, LACHINE, Q

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:VALMET OY;REEL/FRAME:004331/0750

Effective date: 19840503