CA1252665A - Method and apparatus for the thermo-mechanical pulping of wood - Google Patents
Method and apparatus for the thermo-mechanical pulping of woodInfo
- Publication number
- CA1252665A CA1252665A CA000455132A CA455132A CA1252665A CA 1252665 A CA1252665 A CA 1252665A CA 000455132 A CA000455132 A CA 000455132A CA 455132 A CA455132 A CA 455132A CA 1252665 A CA1252665 A CA 1252665A
- Authority
- CA
- Canada
- Prior art keywords
- refiner
- fibrous material
- reject
- reduced
- wood
- 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
Classifications
-
- 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
Abstract
ABSTRACT OF THE DISCLOSURE
An apparatus for thermo-mechanical pulping of wood comprising a first refiner means for reducing the chips to a partially reduced fibrous material, a second refiner means for further reducing the partially reduced fibrous material recovered from the first refiner means to a more completely reduced fibrous material, and means for separating the more completely reduced fibrous material into accept fibrous material and reject fibrous material, wherein the improvement comprises a means for reintroducing the reject fibrous material into the second refiner means and the method of using this apparatus.
An apparatus for thermo-mechanical pulping of wood comprising a first refiner means for reducing the chips to a partially reduced fibrous material, a second refiner means for further reducing the partially reduced fibrous material recovered from the first refiner means to a more completely reduced fibrous material, and means for separating the more completely reduced fibrous material into accept fibrous material and reject fibrous material, wherein the improvement comprises a means for reintroducing the reject fibrous material into the second refiner means and the method of using this apparatus.
Description
8ackground of the Invention 1. Field of the Invention.
The present invention deals with wood pulping and in pdrticular, with the thermo-meçhanical pulping of wood.
The present invention deals with wood pulping and in pdrticular, with the thermo-meçhanical pulping of wood.
2. Descript~on of the Prior Art.
In the production of pulp from wood for the manufacture of newsprint and the like wood is conventionally chipped and then introduced into a refi-ner. Usually this refiner will be the first of two refiners altllouyh single refiner and three refiner systems are known in the art. In the first refiner the chips are moved between a rotatiny disk and a statiorlary disc or betweell double counter rotating discs in a pressuri~ed environment to form a partially reduced fibrous material which will often be in the fornl of bundles or groups of separate fibers. In a two refiner system this partially reduced fibrous material will then he discharged fronl the first refiner and introduced to a second refiner where it will be further reduced, often to its individual fibers. This further reduced fibrous material is then discharged froln the second refiner and after it undergoes latency and cleaning procedures it is screened to separate pulped material which is acceptable for further treat-ment known as accept", from that material9 known as "reject" wllich is not sufficiently reduced and thus unacceptable for further treatment. Generally about 8Q percent of the mater~al recovered from the second refiner is classi-fied as accept. Conventionally it has been the practice to provide still another refiner for the treatment of this reject fibrous ma~eridl. 1~ will be ~S'~ ;5 appreciated, however, that the use o~ this third refiner is expensive in terms of capital costs and plant space. It is, there~ore, the object o~ the present invention to provide an improved me~ns for processing the dbove described reject ~ibrous materi~l, reducing equip~ent and improving the overall energy efficiency of the paper mill.
Summary of the Invention In the present invention wood is first reduced to chips. The wood chips are then introduced to a first refiner to reduce the chips to a partially reduced fibrous material. The partially reduced fibrous material is then discharged from the f~rst refiner and introduced into a second refiner to further reduce it to a more completely reduced fibrous material. This more completely reduced fibrous material from the second refining is separated into accept fibrous materials and reject fibrous material. The second refiner is pressurized with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and is heated to about saturation temperature. The re;ect fibrous material is reintroduced into the second refiner so that the reject fibrous material is further reduced and then discharged from the second refiner.
In the alternative, the wood chips are first introduced to a refiner to reduce the chips to a substantially completely reduced fibrous material and the reduced fibrous material is discharged from the refiner, separated into accept fibrous material and reject fibrous material. The refin~r is pressurized with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heated to about saturation temperature. After the reject fibrous material has been separated, it is reintroduced into the refiner to be further reduced and subsequently discharged.
In another alternative, the wood chips are introduced into a first refiner to reduce the chips to a partially reduced fibrous material which is discharged from the first refiner and successively introduced lnto and discharged from at least one more refiner. Then the accept fibrous material is separated from the re;ect fibrous material. One of the refiners is pressurized with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heated to about saturation temperature and the r~ject fibrous msterial is reintroduced into the pressurized refiner so that the reject fibrous material is further reduced.
Preferably the means for reintroducing the reject fibrous material includes a plug screw feeder.
h~
- 2 ~
~ S Zt~t; 5 Brief Description of the Drawin~
The accompanying drawing is a schematic illustration of the apparatus by which a preferred ennbodiment of the metho~ of the present invention may be carried out.
Detailed Descriptlon Referring to the dr~wing, wood chips are introduced by nneans of a feed conveyor 10 to a retention bin 12. The wood chips are discharged from the retention bin to a pluy screw feeder 14 by means of which they are ~rans-ported to a steaming tube 16 ~also known as a digester) where they are treated - 2a -;~Z5~ i5 with steam. From the base 18 of the steaming tube they are transported by screw 20 to a conventional first refiner appaxatus 22 where the wood chips are treated under steam pressure of about 15-75 p.s.i. greater than atmospheric pressure and at saturation temperature and, as is conventional, are run between a rotating and a stationary disc or between double counter rotating discs. Such refiners are well known in the art and are available, for example, from the Sprout-Waldron Division of Koppers Company, Inc., located at Muncy, Pennsylvania. Saturation temperatures for particular steam pressures are published in Steam Tables by Keenan, Reyes, Hill and Moore (John Wiley & Sons, 1969). The partially reduced fibrous material discharged from the first refiner is then removed by means of line 24 to cyclone 26 in which pressurized steam moves upwardly and is then removed in steam line 28 and in which fibrous material moves downwardly to fiber conveyor 30 which introduces the fibrous material into a second re~iner 32. The pressurized steam removed in line 28 can be used to supplement steam requirement in the drying section of the paper mill. In this second refiner the fibrous material is preferably under steam pressure of from 15-75 p.s.i. greater than atmospheric pressure and saturation temperature and is also run between a stationary and rotating disc. A portion of the steam generated in the second refiner is removed from the second refiner in line 34 and then line 28 and fibrous material along with the balance of the generated steam is removed in steam and fiber line 36 to a second cyclone 38. In this cyclone steam rises to be removed through steam lines 40 and 28. The fibrous material falls and is transported to a device 42 which can maintain pressure within the cyclone while removing fibrous material to an area at atmospheric pressure.
This device 42 may be a swept orifice disc charger, a rotary valve, a plug screw h - lZ~ iS
feeder or a high density stock pump. Line 44 transports fi~rous materidl ~o d conventiondl latency tdnk 48. After the Fibrous mdterial undergoes latency treatment it is remove~ Vid line 50 to conventiondl cleanintJ and separatiny appdratus 52 in which dccept fibrous materidl is separdted from reject fibrous mdteridl. Accept fibrous mdterial is removed in line 54. Reject fibrous material, on the other hand, is transported in d slurry Vid reject line 56 to reject press 5~ where water is pressed from it before entering plug screw feeder 60, After pdsslng through this plug screw feeder the reject fibrous nlaterial is trans~orted by fiber conveyor 3U alony with other fi~rous nldteridlo being discharged from cyclone 26 to the second refiner where it undergoes the same treatment in that refiner dS WdS described above. It will be apprecidted tha~ pressurized stearll production will be proportionally increased with the addition~l work being done o~ the reject stream in the pressurized secondary refiner. The reject fibrous Inateridl is then discharged from the secor,d reFi-ner alony with stealll anrd the fibrous materidl oryinally processed in line 36 dnd is then separated from steam in cyclone 3~ and is further processed in latency tank 48 and cleaning and separating apparatus 52 in the manner descri-bed above.
It will be appreciated thdt a method and apparatus for the thermo-me-chanical pulping of wood has been described in which reject fibers can be pro-cessed at relatively low plant equipment and energy costs has been described, and that this me~hod also affords a way of recovering a yreater proportion of the refining ener~lv in the form of pressurized steam. Although -the invention has been described with a certain degree o-F particularity, it is to be under-stood that the present disclosure has been made only dS dll exdlll~le and that the scope of the invention is defined by what is hereafter claimed. In pdrti-cular, it should be understood that the method and apparatus of the present inven~ion may to adapted for use with d single reFiner system. That is, after ` 12~:jZ~iti5 wood has been chipped and tredted in the slngle refiner until it is substdn-tially completely reduced, reject fibrous materials can then be sep~rated and returned to the sinyle refiner for further reduction dnd additional processing dS iS described above. It will be understood that the present invention also encolnpasses the return o-f reject fibrous material to the first refiner in a two refiner system instead of to the second refiner. Those skilled in the art will recognize that the reintroduction of the reject fibrous nldteridl into the ~irst refiner could under certain circumstances, result in an over-process~
ing of the nlateridl. Under other circulnstdnces however it will be apprecia--0 ted that it would be possible to reintroduce reject fibrous material into thefirst refiner for further reduction. Theredfter it would be renloved along with fibrous material undergoing initial refining~ to the second refiner where it will be still further reduced and then discharged for further ~rocessing in the manner described above. Additionally, in a multiple refiner system having three or Inore refiners it would also be within the scope of the present inven-tion to reduce wood chips in a first refiner and then further reduce the re-sultiny partially reduced fibrous nlateridl in the relnainin(J two or nlore other successively arranged refiners and then separaté accept fronl reject fibrous nlaterial and -findlly reintroduce the reject fibrous nlaterial into any one o-fsaid refiners. At least the first refiner and preferably the other refiners in such a three or Inore refiller systenl would be pressurized with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. yreater than atmospheric ~ressure and be heated to about saturation temperdture. An appdrdtus -for carrying out the above described three or more refiner process which includes a nleans for reintroducing reject fibrous n1ateridl to one oF the refirlers fromthe m~ns for separating accept fibrous material from reject fibrous material is also within the scope of the present invention, and preferably this rein-~troduction ans will ~nclude a plug screw feeder.
_ 5 _
In the production of pulp from wood for the manufacture of newsprint and the like wood is conventionally chipped and then introduced into a refi-ner. Usually this refiner will be the first of two refiners altllouyh single refiner and three refiner systems are known in the art. In the first refiner the chips are moved between a rotatiny disk and a statiorlary disc or betweell double counter rotating discs in a pressuri~ed environment to form a partially reduced fibrous material which will often be in the fornl of bundles or groups of separate fibers. In a two refiner system this partially reduced fibrous material will then he discharged fronl the first refiner and introduced to a second refiner where it will be further reduced, often to its individual fibers. This further reduced fibrous material is then discharged froln the second refiner and after it undergoes latency and cleaning procedures it is screened to separate pulped material which is acceptable for further treat-ment known as accept", from that material9 known as "reject" wllich is not sufficiently reduced and thus unacceptable for further treatment. Generally about 8Q percent of the mater~al recovered from the second refiner is classi-fied as accept. Conventionally it has been the practice to provide still another refiner for the treatment of this reject fibrous ma~eridl. 1~ will be ~S'~ ;5 appreciated, however, that the use o~ this third refiner is expensive in terms of capital costs and plant space. It is, there~ore, the object o~ the present invention to provide an improved me~ns for processing the dbove described reject ~ibrous materi~l, reducing equip~ent and improving the overall energy efficiency of the paper mill.
Summary of the Invention In the present invention wood is first reduced to chips. The wood chips are then introduced to a first refiner to reduce the chips to a partially reduced fibrous material. The partially reduced fibrous material is then discharged from the f~rst refiner and introduced into a second refiner to further reduce it to a more completely reduced fibrous material. This more completely reduced fibrous material from the second refining is separated into accept fibrous materials and reject fibrous material. The second refiner is pressurized with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and is heated to about saturation temperature. The re;ect fibrous material is reintroduced into the second refiner so that the reject fibrous material is further reduced and then discharged from the second refiner.
In the alternative, the wood chips are first introduced to a refiner to reduce the chips to a substantially completely reduced fibrous material and the reduced fibrous material is discharged from the refiner, separated into accept fibrous material and reject fibrous material. The refin~r is pressurized with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heated to about saturation temperature. After the reject fibrous material has been separated, it is reintroduced into the refiner to be further reduced and subsequently discharged.
In another alternative, the wood chips are introduced into a first refiner to reduce the chips to a partially reduced fibrous material which is discharged from the first refiner and successively introduced lnto and discharged from at least one more refiner. Then the accept fibrous material is separated from the re;ect fibrous material. One of the refiners is pressurized with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heated to about saturation temperature and the r~ject fibrous msterial is reintroduced into the pressurized refiner so that the reject fibrous material is further reduced.
Preferably the means for reintroducing the reject fibrous material includes a plug screw feeder.
h~
- 2 ~
~ S Zt~t; 5 Brief Description of the Drawin~
The accompanying drawing is a schematic illustration of the apparatus by which a preferred ennbodiment of the metho~ of the present invention may be carried out.
Detailed Descriptlon Referring to the dr~wing, wood chips are introduced by nneans of a feed conveyor 10 to a retention bin 12. The wood chips are discharged from the retention bin to a pluy screw feeder 14 by means of which they are ~rans-ported to a steaming tube 16 ~also known as a digester) where they are treated - 2a -;~Z5~ i5 with steam. From the base 18 of the steaming tube they are transported by screw 20 to a conventional first refiner appaxatus 22 where the wood chips are treated under steam pressure of about 15-75 p.s.i. greater than atmospheric pressure and at saturation temperature and, as is conventional, are run between a rotating and a stationary disc or between double counter rotating discs. Such refiners are well known in the art and are available, for example, from the Sprout-Waldron Division of Koppers Company, Inc., located at Muncy, Pennsylvania. Saturation temperatures for particular steam pressures are published in Steam Tables by Keenan, Reyes, Hill and Moore (John Wiley & Sons, 1969). The partially reduced fibrous material discharged from the first refiner is then removed by means of line 24 to cyclone 26 in which pressurized steam moves upwardly and is then removed in steam line 28 and in which fibrous material moves downwardly to fiber conveyor 30 which introduces the fibrous material into a second re~iner 32. The pressurized steam removed in line 28 can be used to supplement steam requirement in the drying section of the paper mill. In this second refiner the fibrous material is preferably under steam pressure of from 15-75 p.s.i. greater than atmospheric pressure and saturation temperature and is also run between a stationary and rotating disc. A portion of the steam generated in the second refiner is removed from the second refiner in line 34 and then line 28 and fibrous material along with the balance of the generated steam is removed in steam and fiber line 36 to a second cyclone 38. In this cyclone steam rises to be removed through steam lines 40 and 28. The fibrous material falls and is transported to a device 42 which can maintain pressure within the cyclone while removing fibrous material to an area at atmospheric pressure.
This device 42 may be a swept orifice disc charger, a rotary valve, a plug screw h - lZ~ iS
feeder or a high density stock pump. Line 44 transports fi~rous materidl ~o d conventiondl latency tdnk 48. After the Fibrous mdterial undergoes latency treatment it is remove~ Vid line 50 to conventiondl cleanintJ and separatiny appdratus 52 in which dccept fibrous materidl is separdted from reject fibrous mdteridl. Accept fibrous mdterial is removed in line 54. Reject fibrous material, on the other hand, is transported in d slurry Vid reject line 56 to reject press 5~ where water is pressed from it before entering plug screw feeder 60, After pdsslng through this plug screw feeder the reject fibrous nlaterial is trans~orted by fiber conveyor 3U alony with other fi~rous nldteridlo being discharged from cyclone 26 to the second refiner where it undergoes the same treatment in that refiner dS WdS described above. It will be apprecidted tha~ pressurized stearll production will be proportionally increased with the addition~l work being done o~ the reject stream in the pressurized secondary refiner. The reject fibrous Inateridl is then discharged from the secor,d reFi-ner alony with stealll anrd the fibrous materidl oryinally processed in line 36 dnd is then separated from steam in cyclone 3~ and is further processed in latency tank 48 and cleaning and separating apparatus 52 in the manner descri-bed above.
It will be appreciated thdt a method and apparatus for the thermo-me-chanical pulping of wood has been described in which reject fibers can be pro-cessed at relatively low plant equipment and energy costs has been described, and that this me~hod also affords a way of recovering a yreater proportion of the refining ener~lv in the form of pressurized steam. Although -the invention has been described with a certain degree o-F particularity, it is to be under-stood that the present disclosure has been made only dS dll exdlll~le and that the scope of the invention is defined by what is hereafter claimed. In pdrti-cular, it should be understood that the method and apparatus of the present inven~ion may to adapted for use with d single reFiner system. That is, after ` 12~:jZ~iti5 wood has been chipped and tredted in the slngle refiner until it is substdn-tially completely reduced, reject fibrous materials can then be sep~rated and returned to the sinyle refiner for further reduction dnd additional processing dS iS described above. It will be understood that the present invention also encolnpasses the return o-f reject fibrous material to the first refiner in a two refiner system instead of to the second refiner. Those skilled in the art will recognize that the reintroduction of the reject fibrous nldteridl into the ~irst refiner could under certain circumstances, result in an over-process~
ing of the nlateridl. Under other circulnstdnces however it will be apprecia--0 ted that it would be possible to reintroduce reject fibrous material into thefirst refiner for further reduction. Theredfter it would be renloved along with fibrous material undergoing initial refining~ to the second refiner where it will be still further reduced and then discharged for further ~rocessing in the manner described above. Additionally, in a multiple refiner system having three or Inore refiners it would also be within the scope of the present inven-tion to reduce wood chips in a first refiner and then further reduce the re-sultiny partially reduced fibrous nlateridl in the relnainin(J two or nlore other successively arranged refiners and then separaté accept fronl reject fibrous nlaterial and -findlly reintroduce the reject fibrous nlaterial into any one o-fsaid refiners. At least the first refiner and preferably the other refiners in such a three or Inore refiller systenl would be pressurized with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. yreater than atmospheric ~ressure and be heated to about saturation temperdture. An appdrdtus -for carrying out the above described three or more refiner process which includes a nleans for reintroducing reject fibrous n1ateridl to one oF the refirlers fromthe m~ns for separating accept fibrous material from reject fibrous material is also within the scope of the present invention, and preferably this rein-~troduction ans will ~nclude a plug screw feeder.
_ 5 _
Claims (6)
IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a method for the thermomechanical pulping of wood comprising the steps of:
a. first introducing wood chips to a first refiner to reduce said chips to a partially reduced fibrous material;
b. then discharging said partially reduced fibrous material from said first refiner and introducing it into a second refiner to further reduce it to a more completely reduced fibrous material; and c. then discharging said more completely reduced fibrous material from said refiner and separating accept fibrous materials from reject fibrous material, wherein the improvement comprises the further step of:
d. pressurizing said second refiner with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heating said second refiner to about saturation temperature and reintroducing the reject fibrous material into said second refiner, such that said reject fibrous material is further reduced and then discharged from said second refiner.
a. first introducing wood chips to a first refiner to reduce said chips to a partially reduced fibrous material;
b. then discharging said partially reduced fibrous material from said first refiner and introducing it into a second refiner to further reduce it to a more completely reduced fibrous material; and c. then discharging said more completely reduced fibrous material from said refiner and separating accept fibrous materials from reject fibrous material, wherein the improvement comprises the further step of:
d. pressurizing said second refiner with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heating said second refiner to about saturation temperature and reintroducing the reject fibrous material into said second refiner, such that said reject fibrous material is further reduced and then discharged from said second refiner.
2. In a method for the thermomechanical pulping of wood comprising the steps of:
a. first introducing wood chips to a refiner to reduce said chips to a substantially completely reduced fibrous material; and b. then discharging said reduced fibrous material from said refiner and separating accept fibrous materials from reject fibrous materials, wherein the improvement comprises the further step of:
c. pressurizing said refiner with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heating said refiner to about saturation temperature and reintroducing the reject fibrous material into the refiner, such that said reject fibrous material is further reduced and then discharged from said refiner.
a. first introducing wood chips to a refiner to reduce said chips to a substantially completely reduced fibrous material; and b. then discharging said reduced fibrous material from said refiner and separating accept fibrous materials from reject fibrous materials, wherein the improvement comprises the further step of:
c. pressurizing said refiner with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heating said refiner to about saturation temperature and reintroducing the reject fibrous material into the refiner, such that said reject fibrous material is further reduced and then discharged from said refiner.
3. In a method for thermomechanical pulping of wood comprising the steps of:
a. first introducing wood chips into a first refiner to reduce said chips to a partially reduced fibrous material;
b. then discharging said partially reduced fibrous material from said first refiner and successively introducing it into and then discharging it from at least one more refiner;
c. then separating accept fibrous material from reject fibrous material, wherein the improvement comprises the further step of:
d. pressuring one of said refiners with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heating said pressurized refiner to about saturation temperature and reintroducing the reject fibrous material into said pressurized refiner, such that said reject fibrous material is further reduced.
a. first introducing wood chips into a first refiner to reduce said chips to a partially reduced fibrous material;
b. then discharging said partially reduced fibrous material from said first refiner and successively introducing it into and then discharging it from at least one more refiner;
c. then separating accept fibrous material from reject fibrous material, wherein the improvement comprises the further step of:
d. pressuring one of said refiners with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. and heating said pressurized refiner to about saturation temperature and reintroducing the reject fibrous material into said pressurized refiner, such that said reject fibrous material is further reduced.
4. The method recited in claim 3 wherein, in addition to the refiner into which the reject fibrous material is reintroduced, at least one other of said refiners is pressurized with steam to a pressure of from about 15 p.s.i. to about 75 p.s.i. greater than atmospheric pressure and is heated to about saturation temperature.
5. The method recited in claim 3 wherein there are two refiners and the reject fibrous material is reintroduced into the first refiner.
6. The method of claim 2 wherein the second refiner is pressurized to a pressure of 35-75 psig.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US50880583A | 1983-06-28 | 1983-06-28 | |
| US508,805 | 1990-04-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1252665A true CA1252665A (en) | 1989-04-18 |
Family
ID=24024149
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000455132A Expired CA1252665A (en) | 1983-06-28 | 1984-05-25 | Method and apparatus for the thermo-mechanical pulping of wood |
Country Status (4)
| Country | Link |
|---|---|
| BR (1) | BR8403147A (en) |
| CA (1) | CA1252665A (en) |
| FI (1) | FI842341A (en) |
| SE (1) | SE8403392L (en) |
-
1984
- 1984-05-25 CA CA000455132A patent/CA1252665A/en not_active Expired
- 1984-06-11 FI FI842341A patent/FI842341A/en not_active Application Discontinuation
- 1984-06-26 SE SE8403392A patent/SE8403392L/en not_active Application Discontinuation
- 1984-06-27 BR BR8403147A patent/BR8403147A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| BR8403147A (en) | 1985-06-11 |
| FI842341A (en) | 1984-12-29 |
| SE8403392D0 (en) | 1984-06-26 |
| FI842341A0 (en) | 1984-06-11 |
| SE8403392L (en) | 1984-12-29 |
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| MKEX | Expiry |