CA1267293A - Grinding means for producing mechanical woodpulp - Google Patents
Grinding means for producing mechanical woodpulpInfo
- Publication number
- CA1267293A CA1267293A CA000464530A CA464530A CA1267293A CA 1267293 A CA1267293 A CA 1267293A CA 000464530 A CA000464530 A CA 000464530A CA 464530 A CA464530 A CA 464530A CA 1267293 A CA1267293 A CA 1267293A
- Authority
- CA
- Canada
- Prior art keywords
- grinding
- abrasive
- fragments
- grinding means
- metal
- 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
Links
- 229920001131 Pulp (paper) Polymers 0.000 title claims description 7
- 239000012634 fragment Substances 0.000 claims abstract description 22
- 229910052751 metal Inorganic materials 0.000 claims abstract description 20
- 239000002184 metal Substances 0.000 claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 238000004537 pulping Methods 0.000 claims description 5
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 3
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 3
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 3
- 229910001369 Brass Inorganic materials 0.000 claims description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- 229910000881 Cu alloy Inorganic materials 0.000 claims description 2
- 239000010951 brass Substances 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 239000010949 copper Substances 0.000 claims description 2
- 230000007797 corrosion Effects 0.000 claims description 2
- 238000005260 corrosion Methods 0.000 claims description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 2
- 239000004575 stone Substances 0.000 abstract description 4
- 239000002023 wood Substances 0.000 description 12
- 239000000919 ceramic Substances 0.000 description 8
- 201000011180 Dental Pulp Calcification Diseases 0.000 description 6
- 239000000835 fiber Substances 0.000 description 6
- 239000011159 matrix material Substances 0.000 description 5
- 238000010276 construction Methods 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 239000002923 metal particle Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000012255 powdered metal Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
- C09K3/1409—Abrasive particles per se
- C09K3/1418—Abrasive particles per se obtained by division of a mass agglomerated by sintering
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
- B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
- B24D3/06—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21B1/00—Fibrous raw materials or their mechanical treatment
- D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
- D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
- D21B1/14—Disintegrating in mills
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Ceramic Engineering (AREA)
- Inorganic Chemistry (AREA)
- Polishing Bodies And Polishing Tools (AREA)
Abstract
Abstract In a grinding means according to the invention, such as in a homogeneous grindstone, in an abrasive layer or segment affixed to the surface of a stone body, the hard abrasive fragments are bonded to each other with a sintered metal.
Description
"3~
Grinding means for producing mechanical woodpulp The present invention relates to a grinding means for use in the production of mechanical woodpulp or in pulping, said means comprising abrasive aluminum oxide, wolfram carbide, silicon carbide or the like fragments and a bond for holding them together.
In this application9 the term grinding meansJmeans the above-described homogeneous pulpstone, an abrasive layer affi~ed on the separate pulpstone block, and abrasive segments.
At present, a pulpstone generally comprises a concrete or metal body, having a separate abrasive layer or segments affixed thereon. A segment construction is generally known in the art and it is disclosed e.g. in US Patent publications 2 887 276 and 2 421 885.
In terms of woodpulp quality the most critical component o~ a pulpstone is the grinding means. It must be capable of producing a desired type of woodpulp and it must be capable of sustaining the mechanical and thermal stresses exerted thereon during grinding.
The bond used in presently available grinding means is nearly exclusively ceramic. Thus, the abrasive fragments, usually either A120< or SiC, are bonded together by a ceramic bond, generally glass. Such a co~position is disclosed e.g. in US Patent publication 2 769 286.
The brittleness o~ ceramic materials encourages the wearing thereof, rasulting also in deterioration of the strength properties of pulp. Therefore, the grinding means made with a ceramic bond must o~ten be tooled, which rapidly wears down the grinding means. In tooling, the surface of a ceramic bond is machine~ wi~h a special tool ~o produce a thick ~rray of : ~"
, ~.. ~ ' `
:, :., , , . ,. : .
.~:
, , ~'7~
grooves which usually forms a 28 angle relative to the axis of rotation of a pulpstone. The relative distance of grooves is
Grinding means for producing mechanical woodpulp The present invention relates to a grinding means for use in the production of mechanical woodpulp or in pulping, said means comprising abrasive aluminum oxide, wolfram carbide, silicon carbide or the like fragments and a bond for holding them together.
In this application9 the term grinding meansJmeans the above-described homogeneous pulpstone, an abrasive layer affi~ed on the separate pulpstone block, and abrasive segments.
At present, a pulpstone generally comprises a concrete or metal body, having a separate abrasive layer or segments affixed thereon. A segment construction is generally known in the art and it is disclosed e.g. in US Patent publications 2 887 276 and 2 421 885.
In terms of woodpulp quality the most critical component o~ a pulpstone is the grinding means. It must be capable of producing a desired type of woodpulp and it must be capable of sustaining the mechanical and thermal stresses exerted thereon during grinding.
The bond used in presently available grinding means is nearly exclusively ceramic. Thus, the abrasive fragments, usually either A120< or SiC, are bonded together by a ceramic bond, generally glass. Such a co~position is disclosed e.g. in US Patent publication 2 769 286.
The brittleness o~ ceramic materials encourages the wearing thereof, rasulting also in deterioration of the strength properties of pulp. Therefore, the grinding means made with a ceramic bond must o~ten be tooled, which rapidly wears down the grinding means. In tooling, the surface of a ceramic bond is machine~ wi~h a special tool ~o produce a thick ~rray of : ~"
, ~.. ~ ' `
:, :., , , . ,. : .
.~:
, , ~'7~
grooves which usually forms a 28 angle relative to the axis of rotation of a pulpstone. The relative distance of grooves is
2...3 mrn and depth circa 1 mm. The purpose of tooling is to provide the fibers removed from wood with a space whereby said fibers can leave the grinding zone without becoming re-ground~
In addition, the tooling is used to proportionate the grinding area of a grinding means properly relative to the grinding pressure and the quality o~ pulp to be produced.
Another significant drawback, especially with presently used ceramic grinding segments, is the splitting thereof which also has to do with their brittleness. With the present high-duty pulp grinders this problem is even more pronounced. Splitting of a segment takes place when it is subjected to an intense thermal shock. Such a situation develops e.g. when a block of wood to be ground goes endwise against the abrasive surface.
Since an endwise piece of wood is ground a lot slower than a crosswise one, an extremely high pressure develops at such wood. As a consequence, also the temperature rises locally very high which may result in damage to the segment.
Such damage often results in at least one-day production break on pulp grinder. If the stone cannot be fixed and it must be replaced with a new one, the breakdown will take several days.
The brittle segments also limit deployment of a stone from room temperature. The fact is, namely, that a pulpstone or grindstone must then be carefully heated up to 2 days before commencing actual grinding.
The use of a metal in a grinding means is also prior known from e.g. SE publication prin-t 309 529. This grinding means is fitted with a metal sur~ace, provided with semi-spherical elevations for grinding effect.
, : :
-: .
~:~67~9~.~
Such a solution is practically impossible for several reasonsO
The nodules provided on a metal surface wear away rather rapidly with a consequence that said metal sur~ace must be frequently replaced. The replacement is always inconvenient and a tedious process which accordingly decreaæes production efficiency and overall grinding economy.
An object of this invention is to provide a grinding means used in the mechanical production of woodpulp or in defibration~
such as a homogeneous grinding stone or abrasive segment, whose wear resiætance and mechanical strength are both superior to those of the prior art solutions. According to the invention, this object is achieved in a manner that the bond consists of sintered metal.
In view of the pulping porcess it is preferable that a sintered metal, interspaced between abrasive fragments a~d being softer than said abrasive fragments~ wears away more during grinding than said abrasive fragments.
Due to the conditions prevailing in a pulping process, the preferred metal is a corrosion-resistant or stainless metal, such as stainless or acid-proof steel, e.g. AISI 304 or 316 or 316L. The sintered metal used as a bond can also be copper or a copper alloy, such as brass.
In a grinding means of the invention, the abrasive or grinding fragments can comprise any presently available abrasive materialj such as aluminum oxide, various carbides etc.
.. , The proportion of abrasive fragments in a grinding means is preferably 10-70 percent by volume and most preferably 30-50 percent by volu~e.
~ sintered grinding means, bonded with a metal matrix, can be porous, e.g. 5-30 % of its volume.
.-.: ',,: '~
,, : . :
.
~ ~ .
~67~
The size of abrasive fragments ls preferably circa 150~700 ~m.
Sintering is effected e.g. as follows:
The mixture of powdered metal and abrasive fragments is compressed together with a force sufficient to give the block a handling strength in order to convey it into a furnace without any support means or mould. This is followed by heating the block in the furnace to e.g. 1000-1500C, i.e. suitably below the melting point of a metal employed in a suitable protective gas or vacuum, if desired. Thus, the metal particles adhere to each other building around abrasive fragments a matrix to which said abrasive ~ragments are firmly affixed.
This is a preferable way of producing e.g. grinding segments or sectors, which are conventionally mounted on the surface of e.g. a cylindrical, conical or disc-shaped body made of a metal or some other suitable material.
The analyses have indicated that the compression strength of a grinding segment of the invention, being e.g. up to 1000 N/mm~, is approximately tenfold and its wear resistance up to fivefold as compared with presently available ceramic segments. Despite the high compression strength achieved, a grinding segment of the invention is tough and does not fracture easily the way the available ceramic segments do if subjected to mechanical or thermal shocks.
The improved wear resistance renders possible to make the wearing layer of a grinding means thinner than at present.
Since the strength and toughness of a sintered metal relative to the corresponding properties of a ceramic bond are substantially better, the grinding can be effected with consistencies and temperatures substantially higher than at present whereby, e.g. in pressure grinding, the strength characteristics of pulp are improved and the recovery of heat becomes more effective.
:- .
:':
' . ' ' ' ' ' ~:
~6~
The construction of a grinding means of the invention has been illustrated in th accompanying drawing, which shows the construction of a grinding means of the invention in grinding situation cross-sectioned perpendicularly to the longitudinal axis of a block of wood to be ground.
The drawing illustrates the position where the abrasive fragments 1 on the surface of a grinding means contact the surface of wood 5 to be ground. The grinding direction of a grinding means is designated by -the arrow. At the ~ame time, the fragments penetrate partially into the wood compressing it also, whereby fibers 4 come off the wood as a result of grinding.
The abrasive fragments are bonded together by sintering therearound a matrix 2 of metal particles. It is possible that sintering leaves the matrix with a certain amount (0...20%) of pores 3. When softer bond 2 wears off the abrasive surface, the abrasive fragments will be exposed. As the fragments travel at a high rate of speed against the surface of wood, there is generated in the viscoelastic fiber matrix of wood a high-frequency oscillation which generates the heat that softens the lignin serving as the bond of fibers. This way the fibers can be removed from wood.
A grinding means of the invention can be used not only in pulp grinders but also in a variety of disc, conical or the like refiners, grinders and in other equipment intended for mechanical pulping of wood. In this case, of course, the block design beneath the abrasive surface layer must be constructed appropriately for each purpose. It is possible that abrasive fragments include just one quality or a plurality of qualitics in proper ratio to each other.
':~
In addition, the tooling is used to proportionate the grinding area of a grinding means properly relative to the grinding pressure and the quality o~ pulp to be produced.
Another significant drawback, especially with presently used ceramic grinding segments, is the splitting thereof which also has to do with their brittleness. With the present high-duty pulp grinders this problem is even more pronounced. Splitting of a segment takes place when it is subjected to an intense thermal shock. Such a situation develops e.g. when a block of wood to be ground goes endwise against the abrasive surface.
Since an endwise piece of wood is ground a lot slower than a crosswise one, an extremely high pressure develops at such wood. As a consequence, also the temperature rises locally very high which may result in damage to the segment.
Such damage often results in at least one-day production break on pulp grinder. If the stone cannot be fixed and it must be replaced with a new one, the breakdown will take several days.
The brittle segments also limit deployment of a stone from room temperature. The fact is, namely, that a pulpstone or grindstone must then be carefully heated up to 2 days before commencing actual grinding.
The use of a metal in a grinding means is also prior known from e.g. SE publication prin-t 309 529. This grinding means is fitted with a metal sur~ace, provided with semi-spherical elevations for grinding effect.
, : :
-: .
~:~67~9~.~
Such a solution is practically impossible for several reasonsO
The nodules provided on a metal surface wear away rather rapidly with a consequence that said metal sur~ace must be frequently replaced. The replacement is always inconvenient and a tedious process which accordingly decreaæes production efficiency and overall grinding economy.
An object of this invention is to provide a grinding means used in the mechanical production of woodpulp or in defibration~
such as a homogeneous grinding stone or abrasive segment, whose wear resiætance and mechanical strength are both superior to those of the prior art solutions. According to the invention, this object is achieved in a manner that the bond consists of sintered metal.
In view of the pulping porcess it is preferable that a sintered metal, interspaced between abrasive fragments a~d being softer than said abrasive fragments~ wears away more during grinding than said abrasive fragments.
Due to the conditions prevailing in a pulping process, the preferred metal is a corrosion-resistant or stainless metal, such as stainless or acid-proof steel, e.g. AISI 304 or 316 or 316L. The sintered metal used as a bond can also be copper or a copper alloy, such as brass.
In a grinding means of the invention, the abrasive or grinding fragments can comprise any presently available abrasive materialj such as aluminum oxide, various carbides etc.
.. , The proportion of abrasive fragments in a grinding means is preferably 10-70 percent by volume and most preferably 30-50 percent by volu~e.
~ sintered grinding means, bonded with a metal matrix, can be porous, e.g. 5-30 % of its volume.
.-.: ',,: '~
,, : . :
.
~ ~ .
~67~
The size of abrasive fragments ls preferably circa 150~700 ~m.
Sintering is effected e.g. as follows:
The mixture of powdered metal and abrasive fragments is compressed together with a force sufficient to give the block a handling strength in order to convey it into a furnace without any support means or mould. This is followed by heating the block in the furnace to e.g. 1000-1500C, i.e. suitably below the melting point of a metal employed in a suitable protective gas or vacuum, if desired. Thus, the metal particles adhere to each other building around abrasive fragments a matrix to which said abrasive ~ragments are firmly affixed.
This is a preferable way of producing e.g. grinding segments or sectors, which are conventionally mounted on the surface of e.g. a cylindrical, conical or disc-shaped body made of a metal or some other suitable material.
The analyses have indicated that the compression strength of a grinding segment of the invention, being e.g. up to 1000 N/mm~, is approximately tenfold and its wear resistance up to fivefold as compared with presently available ceramic segments. Despite the high compression strength achieved, a grinding segment of the invention is tough and does not fracture easily the way the available ceramic segments do if subjected to mechanical or thermal shocks.
The improved wear resistance renders possible to make the wearing layer of a grinding means thinner than at present.
Since the strength and toughness of a sintered metal relative to the corresponding properties of a ceramic bond are substantially better, the grinding can be effected with consistencies and temperatures substantially higher than at present whereby, e.g. in pressure grinding, the strength characteristics of pulp are improved and the recovery of heat becomes more effective.
:- .
:':
' . ' ' ' ' ' ~:
~6~
The construction of a grinding means of the invention has been illustrated in th accompanying drawing, which shows the construction of a grinding means of the invention in grinding situation cross-sectioned perpendicularly to the longitudinal axis of a block of wood to be ground.
The drawing illustrates the position where the abrasive fragments 1 on the surface of a grinding means contact the surface of wood 5 to be ground. The grinding direction of a grinding means is designated by -the arrow. At the ~ame time, the fragments penetrate partially into the wood compressing it also, whereby fibers 4 come off the wood as a result of grinding.
The abrasive fragments are bonded together by sintering therearound a matrix 2 of metal particles. It is possible that sintering leaves the matrix with a certain amount (0...20%) of pores 3. When softer bond 2 wears off the abrasive surface, the abrasive fragments will be exposed. As the fragments travel at a high rate of speed against the surface of wood, there is generated in the viscoelastic fiber matrix of wood a high-frequency oscillation which generates the heat that softens the lignin serving as the bond of fibers. This way the fibers can be removed from wood.
A grinding means of the invention can be used not only in pulp grinders but also in a variety of disc, conical or the like refiners, grinders and in other equipment intended for mechanical pulping of wood. In this case, of course, the block design beneath the abrasive surface layer must be constructed appropriately for each purpose. It is possible that abrasive fragments include just one quality or a plurality of qualitics in proper ratio to each other.
':~
Claims (7)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A grinding means for use in the production of mechanical woodpulp or in pulping, said means comprising abrasive aluminum oxide, wolfram carbide, silicon carbide or the like fragments and a bond for holding them together, c h a r a c t e r i z e d in that said bond consists of sintered metal.
2. A means as set forth in claim 1, c h a r a c t e r i z e d in that the sintered metal used as a bond is softer than said abrasive fragments.
3. A means as set forth in claim 1 or 2, c h a r a c t e r-i z e d in that said metal is a corrosion-resistant or stainless metal.
4. A means as set forth in claim 1 or 2, c h a r a c t e r-i z e d in that said metal is copper or a copper alloy, e.g.
brass.
brass.
5. A means as set forth in claim 1, c h a r a c t e r i z e d in that the proportion of abrasive fragments in the grinding means is 10-70 percent by volume.
6. A means as set forth in claim 1, c h a r a c t e r i z e d in that the proportion of abrasive fragments in the grinding means is 30-50 percent by volume.
7. A means as set forth in claim 5 or claim 6 c h a r a c t e r i z e d in that the size of said abrasive fragments is circa 150-700 µm.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI833665A FI68268B (en) | 1983-10-10 | 1983-10-10 | SLIPORGAN FOER FRAMSTAELLNING AV MEKANISK TRAEMASSA |
| FI833,665 | 1983-10-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1267293A true CA1267293A (en) | 1990-04-03 |
Family
ID=8517881
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000464530A Expired CA1267293A (en) | 1983-10-10 | 1984-10-02 | Grinding means for producing mechanical woodpulp |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA1267293A (en) |
| DE (1) | DE3436316A1 (en) |
| FI (1) | FI68268B (en) |
| SE (1) | SE8404871L (en) |
| SU (1) | SU1475490A3 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007125152A1 (en) | 2006-04-28 | 2007-11-08 | Metso Paper, Inc. | Device and method for defibration of wood |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI80087C (en) * | 1986-05-13 | 1990-04-10 | Yhtyneet Paperitehtaat Oy | MALBLOCK VID EN RAFFINOER. |
-
1983
- 1983-10-10 FI FI833665A patent/FI68268B/en not_active Application Discontinuation
-
1984
- 1984-09-28 SE SE8404871A patent/SE8404871L/en not_active Application Discontinuation
- 1984-10-02 CA CA000464530A patent/CA1267293A/en not_active Expired
- 1984-10-04 DE DE19843436316 patent/DE3436316A1/en not_active Withdrawn
- 1984-10-09 SU SU843801009A patent/SU1475490A3/en active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007125152A1 (en) | 2006-04-28 | 2007-11-08 | Metso Paper, Inc. | Device and method for defibration of wood |
| US8172165B2 (en) | 2006-04-28 | 2012-05-08 | Metso Paper, Inc. | Device and method for defibration of wood |
Also Published As
| Publication number | Publication date |
|---|---|
| SE8404871D0 (en) | 1984-09-28 |
| FI833665A0 (en) | 1983-10-10 |
| DE3436316A1 (en) | 1985-04-25 |
| FI68268B (en) | 1985-04-30 |
| SE8404871L (en) | 1985-04-11 |
| SU1475490A3 (en) | 1989-04-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |