US3212721A - Grinding apparatus for treating fibrous material - Google Patents

Grinding apparatus for treating fibrous material Download PDF

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Publication number
US3212721A
US3212721A US224958A US22495862A US3212721A US 3212721 A US3212721 A US 3212721A US 224958 A US224958 A US 224958A US 22495862 A US22495862 A US 22495862A US 3212721 A US3212721 A US 3212721A
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US
United States
Prior art keywords
grinding
piston
pressure
servomotor
pilot valve
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
US224958A
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English (en)
Inventor
Asplund Arne Johan Arthur
Reinhall Rolf Bertil
Penten Lars
Johansson Sven Herbert
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 AB
Original Assignee
Defibrator AB
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 Defibrator AB filed Critical Defibrator AB
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Publication of US3212721A publication Critical patent/US3212721A/en
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D1/00—Methods of beating or refining; Beaters of the Hollander type
    • D21D1/20—Methods of refining
    • D21D1/30—Disc mills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C7/00—Crushing or disintegrating by disc mills
    • B02C7/02—Crushing or disintegrating by disc mills with coaxial discs
    • B02C7/06—Crushing or disintegrating by disc mills with coaxial discs with horizontal axis

Definitions

  • this invention relates to grinding apparatus such as defibrators and refiners for treatment of fibrous material
  • grinding apparatus such as defibrators and refiners for treatment of fibrous material
  • a rotatable and a rotationally stationary grinding member both of which have disc form, for example.
  • the rotatable grinding member is supported by a shaft and axially displaceable by means of a fluid-actuated servomotor for adjusting the interspace between the grinding members and producing a grinding pressure therebetween.
  • the spacing or gap between the grinding discs is not constant but varies with the pressure exerted on said discs by the material to be ground when it passes therebetween.
  • said gap On an increase of the quantity of the material fed into the gap between the discs said gap must be adjusted anew if it is desired to maintain the grinding interspace unchanged.
  • This is the consequence of elongations or stretches in those parts of the apparatus which are subjected to tensile forces, and of compressions in those parts which are subjected to pressure.
  • apparatus of the kind in consideration are operated with so small grinding gaps that the elongations and compressions, respectively, occurring in the various parts of the apparatus are considerably larger, such as ten times larger, than the grinding gap. If the supply of pulp ceases for some reason the grinding discs may come into metallic contact with each other.
  • One main object of the present invention is to provide an improvement of the grinding apparatus with regard to "Ice the drawbacks indicated hereinbefore.
  • a further object of the invention is to bring about the desired improvement of the grinding apparatus by providing means adapted to cause a displacement of the rotatable grinding member relative the stationary grinding member in response to the pressure produced between the grinding members, and thereby to keep the gap between the grinding members at a predetermined value.
  • FIG. 1 is a vertical longitudinal section through a disc refiner constructed according to the invention.
  • FIGS. 2 and 3 are similar sectional views of two alternative embodiments of the invention.
  • equivalent parts have been denoted with the same reference numerals.
  • reference numeral 10 denotes a base of a grinding apparatus, a shaft 12 being supported in said base by two bearings 14 and 16, respectively.
  • the bearing 14 is located in an interior bearing casing 18 and together with this latter member is axially displaceable within an outer bearing casing 20.
  • the bearing 16 which is a combined axial and radial thrust bearing, is axially displaceable together with an inner bearing casing 22 within an outer bearing casing 24.
  • the shaft 12 carries a rotor 25, onto which a grinding disc 28 is rigidly secured and thus is rotated together with the shaft.
  • a stationary grinding disc 30 is fastened by means of bolts to a casing 32, divided at a horizontal level above the shaft.
  • the material to be ground is fed into the apparatus through a central channel 34 formed in the casing 32 and conveyed in an outward direction between the grinding discs 28 and 30, where it is disintegrated. Disposed in the base part of the casing 32 is a discharge opening 36 for removal of the ground fibrous material.
  • a hydraulic servomotor, generally denominated 38, is provided around the shaft 12.
  • Said servomotor comprises a casing 40 which may be made integral with the bearing casing 24, and a piston 42, which is concentric with and, with play, surrounds the shaft 12 and bears against the inner casing 22.
  • the piston 42 has a central flange 44, axially movable within the casing 40.
  • pilot valve 45 Rigidly secured to the casing 40 of the servomotor is a pilot valve 45.
  • Said pilot valve comprises a piston 46 provided with a central flange 47 and two lateral flanges 48 and 50. It has a central chamber 52 and two lateral chambers 54 and 56 adjacent of which the inner diameter of the valve suits to the outer diameter of the flanges.
  • the axial dimension of the piston 46 is kept below the longitudinal dimension of the chamber 52 by a very small value such as one hundredth or a few hundredths of a millimeter.
  • the flanges 48, 50 have an axial dimension which is only inconsiderably minor than the longitudinal dimension of the chambers 54 and 56. In a middle position all flanges are straight in front of their respective chambers.
  • a pipe 58 connecting the central chamber 52 of the pilot valve with an oil sump 60 is provided with a pump 62 and connected with a return pipe 63 controlled by a spring-loaded valve 64. From a space 65 of reduced diameter equal with that of the flanges, which is located between the chambers 52 and 54 of the pilot valve a pipe 66 leads to the chamber 67 located on one side of the flange 44 of the servomotor 42.
  • a pipe 68 connects a further space 69 of reduced diameter of the pilot valve located on the other side of the central chamber 52 with a chamber 70 located on the opposite side of the flange 44-.
  • the lateral chambers 54, 56 are in connection with the sump 60 through return pipes 71 and 72.
  • An arm 74 rigidly secured onto the piston 42 of the servomotor carries a set screw '76, screwed in thereto and extending coaxially with the pilot piston 46 and adapted to act on the end of said piston projecting out of the valve casing.
  • the opposite end of said piston is loaded by a spring 78 tending to displace the piston towards the set screw.
  • a cylinder 80 secured to the arm 74 houses a piston movable therein and on both sides subjected to the action of spring membranes 83, 84.
  • the upper side of the cylinder 80 is through a pipe 86 in connection with the space 69 of the pilot valve, the lower side of said cylinder being connected through a pipe 88 with the space 65.
  • a pin 90 rigidly secured to the piston 82 projects out of the cylinder 80 between the piston 46 and the set screw 76 where said pin has the shape of a wedge or a guide cam 92.
  • the device operates in the following manner:
  • the central chamber 52 of the pilot valve is fed with oil of constant pressure through the pipe 58.
  • the piston 46 is shown in a neutral middle position, in which the pressure oil is distributed equally to the spaces 65 and 69, the pressure thus being the same in these as well as in the both chambers 67 and 70 of the servomotor. If the piston 46 is moving to the left in the figure, the pressure will increase in the space 69, while it will decrease in the space 65. This is due to the fact that the middle flange 47 opens a bigger connecting area between the central chamber 52 and the space 69 at the same time as the lateral flange 50 chokes the passage between the space 69 and pressureless chamber 56.
  • connection between the space 65 and the middle chamber 52 is choked and further a bigger passage is opened between the space 65 and the pressureless lateral chamber 54.
  • the material to be ground fed between the grinding discs 28 and 30 is thus subjected to a pressure the magnitude of which depends on the position of the piston 46 of the pilot valve and which is determined by means of the set screw 76.
  • the piston 46 of the pilot valve is kept by the spring 78 continuously pressed against the adjusting screw 76 and thus follows the latter in its axial movements.
  • the set screw 76 is entrained also, since it is secured to the arm 74 connected with the piston 42.
  • the piston 46 of the pilot valve follows with the set screw 76.
  • An increased pressure is mobilized to act on the piston 42 of the servomotor in order to restore the earlier gap between the grinding discs.
  • This gap is desired to be of an order of magnitude of only one hundredth or some hundredths of a millimeter. If, on the contrary, the grinding discs, due to non-arrival of fed material, should tend to approach one another, the piston 42 of the servomotor and the set screw 76 will follow and cause the piston 46 of the pilot valve to move to the right hand. This movement will result in an increase of the pressure in the space 65 of the pilot valve and in the chamber 67 sure.
  • the wedge-formed member 92 and the members cooperating with said member have as their object to compensate for the compressions and stretches, respectively, which appear in the apparatus parts transmitting the grinding pressure.
  • a pressure is exerted on the piston of the servomotor in a direction towards the stationary grinding disc 30, the apparatus parts participating in the pressure transmission will be compressed, while an elongation or stretching will take place in those parts of the base 10, which are located between this grinding disc and the casing 40 of the servomotor.
  • This compression and elongation amount as already stated, to many times the size of the grinding gap.
  • the elongation causes the casing of the pilot valve 45 to be displaced to the left.
  • the piston 46 can be kept in such a position in relation to the casing of the pilot valve that the pressure acting in the chamber '70 of the servomotor is the pressure required for the performance of the grinding operation with the desired and predetermined grinding gap.
  • the axial position of the piston 46 is thus governed not only by the set screw 76 but also by the cam member 92 and the total effect of their actions is to pay attention also to the compression and elongation in the apparatus.
  • FIG. 2 shows an embodiment with a mechanically operating device for compensation of the compression and the elongation in the apparatus.
  • Rigidly secured to the casing 32 is a bracket 96 in which one end of a rod 98 is pivotable about a pivot 100.
  • the other end of the rod is connected to a pivot 101 on a link 102 which is mounted on the pivot 103 in a bracket 104 rigidly secured onto the outer bearing casing 24 integral with the casing 40 of the servomotor on one hand, and on a pivot 106 of the casing 45 of the pilot valve.
  • the bar 98 has a length approximately corresponding to the length of that part of the base of the apparatus which is subjected to elongation due to the action of the grinding pressure.
  • the pivot 101 of the bar 98 is located between the pivots 103 and 106 and causes the arm 102 due to the elongation to turn clockwise according to FIG. 2, relatively to the bracket 104.
  • the casing 45 of the pilot valve is thus displaced to the right.
  • the length of the levers represented by the spacing between the pivots 101 and 103 at the one hand and the pivots 103 and 106 is determined so as to take into consideration also the compression in those parts which transmit the grinding pressure from the piston 42 of the servomotor to the casing 32 and which in accordance with the explanation above cause a displacement of the set screw 76 in the right-hand direction in the figure.
  • the casing 45 of the pilot valve will in other words take such a position in relation to the piston 46 of the pilot valve adjacent the set screw 76 as if no compression nor elongation had taken place. Otherwise, the hydraulic system operates in the same manner as described hereinbefore in connection with FIG. 1.
  • the piston 42 of the servomotor cooperates with a stationary stop which in a manner known per se determines the minimum of the width of the grinding gap existing between the grinding discs 28 and 30.
  • said stop consists :of a ring 110 screwed onto the part of the piston of the servomotor projecting out of the casing 40.
  • the piston of the servomotor cannot be moved more towards the rotationally stationary grinding disc than until the ring 100 bears against the end face 112 of the motor casing 40.
  • the ring 110 is to determine the width of the grinding gap to assume a desired value.
  • the chambers 67 and 70 of the servomotor have pipes 112 and 114 respectively, opening thereinto and adapted to become connected by means of a multi-way valve 116 with tone or the other of two pipes 118, 120, respectively, of which the former opens to the pressure side of the pump 62 and the latter into the sump 60.
  • the pressure pipe 118 In the position of valve 116 shown in the FIG. 3 the pressure pipe 118 is in connection with the pipe 114.
  • the chamber 70 of the servomotor is thus under pressure, while the chamber 67 is over the valve 116 connected to the return pipe 120 and without pressure.
  • the pressure fluid is instead fed into the chamber 68, whereas the chamber 70 becomes pressureless.
  • the ring 110 is on its external face provided with teeth engaging a gear 122, carried on a shaft 124 of an electric motor 126.
  • an elongation meter 128 is provided on the casing 32 at a place subjected to elongation due to the action of the grinding pressure produced between the grind-ing discs.
  • Thi meter is in a manner known per se of such type as to have its electrical resistance to vary with its length.
  • the elongation meter is connected to a :relay 130 which amplifies the impulses emitted the meter and transmits them to the electric motor 126 through a wire 132.
  • the elongation meter thus sends impulses to the electric motor 126 in response to the changes in elongation corresponding to variations of the grinding pressure.
  • the elongation meter 128 causes the electric motor 126 to operate and to turn the ring 110 so as to become unscrewed, i.e. towards the left in the figure.
  • the rotating grinding disc 28 is thus capable of main taining that position relative the stationary grinding disc 30 which corresponds to the width of the determined minimum gap.
  • the motor screws the ring 110 in the direction towards the casing 40 of the servomotor so as even now to produce a compensation and under all circumstances to prevent metallic contact between the grinding discs.
  • a grinding apparatus for treatment of fibrous material comprising a rotatable and non-rotative grinding member, of which the former includes a shaft supporting said rotatable grinding member and axially displaceable by means of a servomotor piston adapted to be actuated from both sides by a fluid for adjusting the spacing between said grinding members and for producing a grinding pressure between the same, means to actuate the piston of the servomotor, said means being adapted to cause a displacement of the rotatable grinding member relative the grinding member in response to compression and elongation, respectively, produced depending on the grinding pressure, in the pressure transmitting parts of the apparatus so as to keep the gap between the grinding members at a predetermined value.
  • a grinding apparatus as claimed in claim 1, a part of electric elongation meter disposed on an apparatus exposed to elongation, a motor actuated by said elongation meter and a driving mechanism connected with said motor and adapted on actuation by an impulse from said elogation meter to displace the piston of the servomotor relatively to the casing surrounding said piston in response to the elongation or compression produced in the apparatus.
  • conduits on each of both sides of said servomotor piston in connection through a pilot valve with a pressure source and with an outlet, respectively, the pilot valve having a stationary cylinder and a movable piston which are displaceable in relation to one another for adjustment of the grinding pressure exercised by said servomotor piston in response to the relative position between said piston and a base part of the apparatus exposed to elongation, the apparatus further comprising an element adapted to counteract a change in the relative position of the parts of said pilot valve caused by the compression and elongation produced in said base.
  • adjusting means adapted to determine the position of the movable piston of the pilot valve, said adjusting means being connected with the piston of the servomotor and adjustable for alteration of the mutual position of said movable pilot valve piston and said servo-motor piston.
  • said element being disposed to be under actuation by a pressure diiference of the fluid created in the pilot valve for causing a displacement of the movable piston of said pilot valve relative to the servomotor piston so as to correspond to the displacement caused by the compression and elongation of the piston relative to the surrounding casing of the servomotor but in a direction opposite to said displacement.
  • the pilot valve having its piston movable in relation to its cylinder but stationary in relation to the piston of the servomotor, said cylinder being stationary in relation to a place located on the base of the apparatus adjacent the stationary grinding member.
  • said element having the form of a cam-like member determining the position of the piston of the pilot valve relative to said adjusting means and being displaceable by means of a piston-like member located in a casing in response to the pressure exercised by the fluid on the piston of the servomotor, said cam-like member having a surface formed so as to cause the spacing between said adjusting means and the piston part of said pilot valve to be corrected in correspondence to the compression and elongation produced in the base of the apparatus.
  • said cylinder of the pilot valve being connected with said place located on the base of the apparatus through a bar and a gear so as to cause the relative displacement of said cylinder relative to the piston part of the pilot valve to increase more than the valve corresponding to the elongation and thus also includes a change of position of the piston of the servomo-tor due, to the compression of the apparatus parts exposed to pressure.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)
  • Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
US224958A 1961-09-22 1962-09-20 Grinding apparatus for treating fibrous material Expired - Lifetime US3212721A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE946161 1961-09-22

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US3212721A true US3212721A (en) 1965-10-19

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US224958A Expired - Lifetime US3212721A (en) 1961-09-22 1962-09-20 Grinding apparatus for treating fibrous material

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US (1) US3212721A (enrdf_load_stackoverflow)
AT (1) AT245348B (enrdf_load_stackoverflow)
CH (1) CH414334A (enrdf_load_stackoverflow)
GB (1) GB1021702A (enrdf_load_stackoverflow)
NO (1) NO122289B (enrdf_load_stackoverflow)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3302893A (en) * 1964-02-18 1967-02-07 Wedco Disc mill
US3438351A (en) * 1966-09-02 1969-04-15 Morden Machines Co Means for simultaneously indicating the spacing between two opposed attritioning elements and their condition of wear
US3506199A (en) * 1968-01-18 1970-04-14 Black Clawson Co Paper pulp refiner control system
US3737109A (en) * 1970-10-26 1973-06-05 Difibrator Ab Double-acting axial thrust and radial bearings for grinding apparatus
US3799456A (en) * 1972-06-14 1974-03-26 Bauer Bros Co Refiner plate clearance control system
US3810584A (en) * 1971-09-17 1974-05-14 Escher Wyss Gmbh Grinding apparatus for fibrous material
US3841573A (en) * 1971-09-17 1974-10-15 Escher Wyss Gmbh Grinding apparatus for fibrous material
US3938732A (en) * 1974-09-16 1976-02-17 Iowa Manufacturing Company Adjustment means for roll crushers with gas hydraulic springs
US3977611A (en) * 1974-03-27 1976-08-31 Sca Development Aktiebolag Apparatus for refining fiber material
US3987973A (en) * 1974-03-11 1976-10-26 Rolf Bertil Reinhall Device in machine elements with closed casing
US4073442A (en) * 1975-04-07 1978-02-14 Defibrator Aktiebolag Electrically controlled system for regulating the grinding space in a grinding apparatus
WO1987001056A1 (en) * 1985-08-20 1987-02-26 Floden Mats Method for refining fibrous material
US4801099A (en) * 1984-09-05 1989-01-31 Reinhall Rolf Bertil Combined hydrostatic/hydrodynamic bearing system for grinding apparatus
WO1990001371A1 (en) * 1988-08-04 1990-02-22 Sunds Defibrator Industries Aktiebolag Stress regulator for pulp grinding apparatus and method
US5067660A (en) * 1988-08-04 1991-11-26 Sunds Defibrator Ab Stress regulator for pulp grinding apparatus and method
US5398876A (en) * 1993-07-15 1995-03-21 Reinhall; Ulf B. Apparatus and method for refining pulp stock
US20070089569A1 (en) * 2005-10-20 2007-04-26 Alltrade Tools Llc Opening device & Method of manufacture
US20110142704A1 (en) * 2009-12-15 2011-06-16 Aktiebolaget Skf Roller Bearing Assembly
CN102400406A (zh) * 2011-11-09 2012-04-04 华南理工大学 中浓液压双盘磨浆机

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4986480A (en) * 1989-06-29 1991-01-22 Kamyr Ab Method and apparatus for feeding a conical refiner
CN107115928B (zh) * 2017-06-28 2019-04-02 南京工程学院 一种研磨间隙可控的橡胶颗粒胶粉制备装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2548599A (en) * 1948-11-02 1951-04-10 Gen Electric Clearance control
US2971704A (en) * 1955-11-07 1961-02-14 Asplund Arne J A Grinding apparatus for disintegrating fibrous material

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2548599A (en) * 1948-11-02 1951-04-10 Gen Electric Clearance control
US2971704A (en) * 1955-11-07 1961-02-14 Asplund Arne J A Grinding apparatus for disintegrating fibrous material

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3302893A (en) * 1964-02-18 1967-02-07 Wedco Disc mill
US3438351A (en) * 1966-09-02 1969-04-15 Morden Machines Co Means for simultaneously indicating the spacing between two opposed attritioning elements and their condition of wear
US3506199A (en) * 1968-01-18 1970-04-14 Black Clawson Co Paper pulp refiner control system
US3737109A (en) * 1970-10-26 1973-06-05 Difibrator Ab Double-acting axial thrust and radial bearings for grinding apparatus
US3810584A (en) * 1971-09-17 1974-05-14 Escher Wyss Gmbh Grinding apparatus for fibrous material
US3841573A (en) * 1971-09-17 1974-10-15 Escher Wyss Gmbh Grinding apparatus for fibrous material
US3799456A (en) * 1972-06-14 1974-03-26 Bauer Bros Co Refiner plate clearance control system
US3987973A (en) * 1974-03-11 1976-10-26 Rolf Bertil Reinhall Device in machine elements with closed casing
US3977611A (en) * 1974-03-27 1976-08-31 Sca Development Aktiebolag Apparatus for refining fiber material
US3938732A (en) * 1974-09-16 1976-02-17 Iowa Manufacturing Company Adjustment means for roll crushers with gas hydraulic springs
US4073442A (en) * 1975-04-07 1978-02-14 Defibrator Aktiebolag Electrically controlled system for regulating the grinding space in a grinding apparatus
US4801099A (en) * 1984-09-05 1989-01-31 Reinhall Rolf Bertil Combined hydrostatic/hydrodynamic bearing system for grinding apparatus
US4890796A (en) * 1984-09-05 1990-01-02 Sunds Defibrator Ab Combined hydrostatic/hydrodynamic bearing system for grinding apparatus
WO1987001056A1 (en) * 1985-08-20 1987-02-26 Floden Mats Method for refining fibrous material
US4943347A (en) * 1985-08-20 1990-07-24 Mats Floden Method of refining fibrous material by controlling the feed rate of material or the gap distance between discs
WO1990001371A1 (en) * 1988-08-04 1990-02-22 Sunds Defibrator Industries Aktiebolag Stress regulator for pulp grinding apparatus and method
US5067660A (en) * 1988-08-04 1991-11-26 Sunds Defibrator Ab Stress regulator for pulp grinding apparatus and method
US5398876A (en) * 1993-07-15 1995-03-21 Reinhall; Ulf B. Apparatus and method for refining pulp stock
US20070089569A1 (en) * 2005-10-20 2007-04-26 Alltrade Tools Llc Opening device & Method of manufacture
US20110142704A1 (en) * 2009-12-15 2011-06-16 Aktiebolaget Skf Roller Bearing Assembly
US8678664B2 (en) 2009-12-15 2014-03-25 Aktiebolaget Skf Roller bearing assembly
CN102400406A (zh) * 2011-11-09 2012-04-04 华南理工大学 中浓液压双盘磨浆机
CN102400406B (zh) * 2011-11-09 2014-02-26 华南理工大学 中浓液压双盘磨浆机

Also Published As

Publication number Publication date
GB1021702A (en) 1966-03-09
AT245348B (de) 1966-02-25
NO122289B (enrdf_load_stackoverflow) 1971-06-07
CH414334A (de) 1966-05-31

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