SE2050527A1 - A defibrator system and a return steam pipe - Google Patents

A defibrator system and a return steam pipe

Info

Publication number
SE2050527A1
SE2050527A1 SE2050527A SE2050527A SE2050527A1 SE 2050527 A1 SE2050527 A1 SE 2050527A1 SE 2050527 A SE2050527 A SE 2050527A SE 2050527 A SE2050527 A SE 2050527A SE 2050527 A1 SE2050527 A1 SE 2050527A1
Authority
SE
Sweden
Prior art keywords
steam pipe
return steam
preheater
defibrator
arrangement
Prior art date
Application number
SE2050527A
Other languages
Swedish (sv)
Other versions
SE543739C2 (en
Inventor
Örjan Ahlgren
Jan Laredius
Thommy Lindblom
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
Priority to SE2050527A priority Critical patent/SE2050527A1/en
Priority to EP21800699.7A priority patent/EP4146861A1/en
Priority to PCT/SE2021/050276 priority patent/WO2021225491A1/en
Publication of SE543739C2 publication Critical patent/SE543739C2/en
Publication of SE2050527A1 publication Critical patent/SE2050527A1/en

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
    • 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

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)
  • Drying Of Solid Materials (AREA)
  • Disintegrating Or Milling (AREA)

Abstract

A defibrator system and a method for defibrating wood chips, said defibrator system comprising:a preheater comprising a preheater wood chips inlet and a preheater wood chips outlet;a defibrator comprising a defibrator wood chips inlet and a defibrator wood fibre outlet;a feed screw arrangement which is connected to said preheater wood chips outlet and to said defibrator wood chips inlet and configured for feeding wood chips from the preheater wood chips outlet to the defibrator wood chips inlet; and a return steam pipe arrangement comprising a return steam pipe which is extending between a return steam pipe first end and a return steam pipe second end and which is connected in the return steam pipe first end to the feed screw arrangement and in the return steam pipe second end to the preheater, wherein said return steam pipe is configured for transferring steam from the feed screw arrangement to the preheater,wherein the return steam pipe arrangement comprises a first sensor arrangement provided in connection with the return steam pipe at a position which is closer to the return steam pipe first end than the return steam pipe second end.

Description

A defibrator system and a return steam pipe TECHNICAL FIELD OF THE INVENTION The present invention relates to a defibrator system and to a return steam pipe arrangement in a defibrator system and to a method for defibrating wood chips.
BACKGROUND A defibrator system comprises a preheater for preheating wood chips before they aredefibrated in a defibrator. The preheated wood chips are transferred out from the preheaterby for example a plug feed screw into another feed screw which is a ribbon feed screw whichtransfers the preheated wood chips into the defibrator. The ribbon feed screw is ho||owwhereby a return flow of steam is allowed from the defibrator through the ribbon feed screw.A return steam pipe is further provided in the defibrator system for balancing the pressurebetween the ribbon feed screw and the preheater. The return steam pipe will transfer steamfrom the ribbon feed screw back to the preheater. The return steam pipe is connected in one end to the ribbon feed screw and in the other end to a top part ofthe preheater.
There may be problems with clogging in the return steam pipe and the return steam pipe may have to be cleaned repeatedly.
SUMMARY An object of the invention is to provide a more stable and reliable defibration process in the defibrator system.
A further object of the invention is to improve the process of returning steam from the defibrator to the preheater.
This is achieved by a defibrator system, by a method for defibrating wood chips and by a return steam pipe arrangement according to the independent claims.
According to one aspect of the invention a defibrator system for defibrating wood chips is provided. Said defibrator system comprises: a preheater comprising a preheater wood chips inlet and a preheater wood chipsoutlet; a defibrator comprising a defibrator wood chips inlet and a defibrator wood fibreoutlet; a feed screw arrangement which is connected to said preheater wood chips outletand to said defibrator wood chips inlet and configured for feeding wood chips fromthe preheater wood chips outlet to the defibrator wood chips inlet; and a return steam pipe arrangement comprising a return steam pipe which isextending between a return steam pipe first end and a return steam pipe secondend and which is connected in the return steam pipe first end to the feed screwarrangement and in the return steam pipe second end to the preheater, whereinsaid return steam pipe is configured for transferring steam from the feed screw arrangement to the preheater, wherein the return steam pipe arrangement comprises a first sensor arrangementprovided in connection with the return steam pipe at a position which is closer to the return steam pipe first end than the return steam pipe second end.
According to another aspect ofthe invention a method for defibrating wood chips is provided, said method comprising the steps of: providing wood chips into a preheater through a preheater wood chips inlet;preheating said wood ships in the preheater; feeding said preheated wood chips from a preheater wood chips outlet of thepreheater to a defibrator wood chips inlet of a connected defibrator by a feedscrew arra ngement which is connecting said preheater wood chips outlet with saiddefibrator wood chips inlet; defibrating said wood chips in said defibrator; and returning steam from the defibrator via the feed screw arrangement to the preheater via a return steam pipe which is extending between a return steam pipe first end and a return steam pipe second end and which is connecting the feed screw arrangement and the preheater, wherein the method further comprises the step of measuring a feature in the returnsteam pipe with a first sensor arrangement at a position which is closer to the return steam pipe first end than the return steam pipe second end.
According to another aspect of the invention a return steam pipe arrangement is providedcomprising a return steam pipe which is extending between a return steam pipe first end anda return steam pipe second end and which is configured for being connectable in the returnsteam pipe first end to a feed screw arrangement provided for feeding wood chips between apreheater and a defibrator in a defibrator system and in the return steam pipe second end tothe preheater of the defibrator system, wherein said return steam pipe is configured forreturning steam from the defibrator and the feed screw arrangement to the preheater andwherein the return steam pipe arrangement comprises a first sensor arrangement providedin connection with the return steam pipe at a position which is closer to the return steam pipe first end than the return steam pipe second end.
Hereby a defibrator system is provided in which a feature of the steam which is passing thereturn steam pipe can be measured closer to the connection of the return steam pipe to thefeed screw arrangement than to the preheater. This measured feature can be used forevaluating if there is for example a stop or a reduced possibility for the steam to pass throughthe return steam pipe. Hereby such a problem can be taken care of by for example cleaningthe pipe in good time. Hereby a defibration process efficiency can be improved and the process will be more reliable and predictable.
Furthermore, a return steam pipe arrangement is provided according to the invention whichcan be connected to an already existing defibrator system which return steam pipearrangement provides the possibility to measure a feature of the steam passing the return steam pipe at a position which is closer to the feed screw arrangement than the preheater. ln one embodiment of the invention the first sensor arrangement is provided in connectionwith the return steam pipe within a distance from the return steam pipe first end which is less than 1/4 of a total length (L) ofthe return steam pipe. ln one embodiment of the invention the defibrator system further comprises a second sensorarrangement which is provided either in connection with the return steam pipe within adistance from the return steam pipe second end which is less than 1/4 of a total length (L) of the return steam pipe or in a top portion of the preheater. ln one embodiment of the invention the first sensor arrangement is provided in connectionwith the return steam pipe first end and the second sensor arrangement is provided in connection with the return steam pipe second end. ln one embodiment of the invention the first and second sensor arrangements comprises atleast one same type of sensor for comparative measurements between the return steam pipe first and second ends. ln one embodiment of the invention said preheater wood chips inlet is arranged in a topportion ofsaid preheaterand said preheaterwood chips outlet is arranged in a bottom portion of said preheater. ln one embodiment of the invention said return steam pipe second end is connected to a top portion of the preheater. ln one embodiment of the invention the feed screw arrangement comprises a ribbon feed SCFQW. ln one embodiment ofthe invention the feed screw arrangement comprises a plug feed screwand a ribbon feed screw connected to each other, wherein the plug feed screw is connectedto the preheater woodchips outlet and is configured for feeding wood chips into the ribbonfeed screw, which is connected to the defibrator wood chips inlet and is configured fortransferring the wood chips from the plug feed screw to the defibrator, wherein said ribbonfeed screw comprises a hollow centre allowing steam to travel through the ribbon feed screw in the opposite direction to a material feeding direction ofthe ribbon feed screw. ln one embodiment of the invention the first and a possible second sensor arrangement cancomprise one or more of: a pressure sensor, a temperature sensor, a flow sensor and a speed SQHSOF.
Further embodiments are described in the detailed description and in the patent claims.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows schematically a perspective view, pa rtly in cross section, of a defibrator system according to one embodiment of the invention.Figure 2a is a cross section ofthe defibrator system as shown in Figure 1.
Figure 2b is a cross section of a defibrator system according to another embodiment of the invention.
Figure 3 shows schematically a return steam pipe arrangement according to one embodiment of the invention.
Figure 4 is a flow chart describing some of the steps of a method for defibrating wood chips according to the invention.
DETAILED DESCRIPTION OF El\/lBODIl\/IENTS Figure 1 shows schematically a perspective view, partly in cross section, of a defibrator system1 according to one embodiment of the invention. Figure 2a shows schematically a crosssection ofthe same defibrator system 1 as shown in Figure 1. Figure 2b is a cross section of adefibrator system 1' according to another embodiment of the invention. Figure 3 showsschematically a return steam pipe arrangement 21 according to one embodiment of theinvention. The invention is now described with reference to all drawings 1-3. I\/lost of thedetails are the same for all embodiments and these details are given the same reference numbers.
The defibrator system 1; 1' comprises a preheater 3 comprising a preheater wood chips inlet5a and a preheater wood chips outlet 5b. The preheater wood chips inlet 5a is arranged in atop portion 6a of said preheater 3 and said preheater wood chips outlet 5b is arranged in abottom portion 6b of said preheater 3. Wood chips are fed into the preheater 3 via thepreheater wood chips inlet 5a for being treated in the preheater before they are transferredout through the preheater wood chips outlet 5b for being defibrated. The defibrator system1; 1' comprises further a defibrator 7 configured for defibrating the wood chips after they have been treated in the preheater 3. The defibrator 7 comprises a defibrator wood chips inlet 9a and a defibrator wood fibre outlet 9b. The defibrator system 1; 1' comprises furthermorea feed screw arrangement 11 which is connecting said preheater 3 with the defibrator 7. Thefeed screw arrangement 11 is connected to said preheater wood chips outlet 5b and to saiddefibrator wood chips inlet 9a and is configured for feeding wood chips from the preheaterwood chips outlet 5b to the defibrator wood chips inlet 9a. The feed screw arrangement 11comprises in this embodiment one plug feed screw 13 and one ribbon feed screw 15connected to each other, wherein the plug feed screw 13 is connected to the preheaterwoodchips outlet 5b and is configured for feeding wood chips into the ribbon feed screw 15,which is connected to the defibrator wood chips inlet 9a and is configured for transferring thewood chips from the plug feed screw 13 to the defibrator 7. ln other embodiments the plugfeed screw could be exchanged to another feeding arrangement between the preheater woodchips outlet 5b and the ribbon feed screw. The ribbon feed screw 15 comprises a hollow centreallowing steam to travel through the ribbon feed screw in the opposite direction to the woodchips feeding direction through the ribbon feed screw 15. The defibrator system 1; 1'comprises furthermore a return steam pipe arrangement 21 comprising a return steam pipe23 which is extending between a return steam pipe first end 25a and a return steam pipesecond end 25b and which is connected in the return steam pipe first end 25a to the feedscrew arrangement 11 and in the return steam pipe second end 25b to the preheater 3. Saidreturn steam pipe second end 25b is connected to the top portion 6a of the preheater 3. Thereturn steam pipe 23 is configured for transferring steam from the feed screw arrangement11 to the preheater 3. The steam which is released during defibration travels back through theribbon feed screw and will raise the pressure within the feed screw arrangement. Forbalancing the pressure between the feed screw arrangement and the preheater the return steam pipe 23 is provided for transferring the steam to the preheater 3.
According to the invention the return steam pipe arrangement 21 comprises a first sensorarrangement 31a provided in connection with the return steam pipe 23 at a position which iscloser to the return steam pipe first end 25a than the return steam pipe second end 25b. Withsuch a first sensor arrangement 31a a feature can be measured in the return steam pipe 23and by measuring this feature closer to the return steam pipe first end 25a than the returnsteam pipe second end 25b this measurement can be compared to a measurement performed for example in a top portion 6a of the preheater 3 where another sensor may be provided. ln one embodiment of the invention a second sensor arrangement 31b is provided in the topportion 6a of the preheater 3. This is shown in Figure 1 and in Figure 2a. ln Figure 2b and inFigure 3 another embodiment is shown where a second sensor arrangement 31b is providedin connection with the return steam pipe 23 instead. The second sensor arrangement 31b isin this embodiment positioned closer to the return steam pipe second end 25b than the returnsteam pipe first end 25a. ln some embodiments the first sensor arrangement 31a can bepositioned within a distance from the return steam pipe first end 25a which is less than 1/4 orless than 1/6 of a total length L ofthe return steam pipe. The second sensor arrangement 31bcan be positioned within a distance from the return steam pipe second end 25b which is lessthan 1/4 or less than 1/6 of a total length L of the return steam pipe. ln some embodimentsof the invention the first sensor arrangement 31a can be positioned in connection with or invicinity ofthe return steam pipe first end 25a and the second sensor arrangement 31b can bepositioned in connection with or in vicinity ofthe return steam pipe second end 25a. ln Figure3 a return steam pipe arrangement 21 is shown schematically, wherein the return steam pipearrangement 21 comprises a return steam pipe 23, a first sensor arrangement 31a and asecond sensor arrangement 31b. ln another embodiment the return steam pipe arrangement21 comprises only the first sensor arrangement 31a and the second sensor arrangement 31bcan be provided in a top portion 6a ofthe preheater 3 itself or an already provided sensor, forexample an already provided pressure sensor in the preheater, can be used for performingmeasurements to be compared with measurements of the first sensor arrangement 31a.According to one aspect of the invention a return steam pipe arrangement 21 which can beconnected to an already existing defibrator system is provided. The return steam pipearrangement 21 is configured for being connectable in the return steam pipe first end 25a toa feed screw arrangement 11 provided for feeding wood chips between a preheater 3 and adefibrator 7 in a defibrator system 1;1' and in the return steam pipe second end 25b to thepreheater 3 of the defibrator system 1; 1'. The first and the possible second sensorarrangements 31s, 31b can be provided within a distance from the return steam pipe first andsecond ends 25a, 25b respectively which is for example less than 1/4 or less than 1/6 ofa totallength (L) ofthe return steam pipe 23 as described above. The return steam pipe arrangement21 can comprise in the return steam pipe first end 25a a first connection device 41a configured for connection to a feed screw arrangement 11 in a defibrator system 1; 1' and in the return steam pipe second end 25b a second connection device 41b configured for connection to the preheater 3 of the defibrator system 1; 1'.
Suitably the first and second sensor arrangements 31a, 31b comprises at least one same typeof sensor for comparative measurements between the return steam pipe first and secondends 25a, 25b. The first sensor arrangement 31a and the second sensor arrangement 31b cancomprise for example one or more of: a pressure sensor, a temperature sensor, a flow sensorand a speed sensor. The first sensor arrangement 31a can be provided in connection with thereturn steam pipe 23 such that a feature inside the return steam pipe 23 can be measured bythe first sensor arrangement 31a. The first sensor arrangement 31a can also be positioneddirectly inside the return steam pipe 23. lf a second sensor arrangement 31b is provided inconnection with the return steam pipe 23 this can also be provided in connection with the return steam pipe or directly inside the return steam pipe 23.
The feature measured by the first and second sensor arrangements 31, 31b can be used forassessing a condition of the return steam pipe 23, for example if the return steam pipe hasbeen clogged and needs to be cleaned this can be seen as a difference in the measured featurebetween the first and second sensor arrangements 31a, 31b or a difference in the measuredfeature between the first sensor arrangement 31a and another sensor provided in a topportion 6a of the preheater 3. For example, if pressure is measured a clogged return steampipe 23 would show up as different pressure values measured by the first and second sensor arrangements 31a, 31b.
According to the invention a method for defibrating wood chips is also provided. The methodsteps are illustrated in a flow chart in Figure 4. The method comprises the following steps described in order below:S1: Providing wood chips into a preheater 3 through a preheater wood chips inlet 5a.S2: Preheating said wood ships in the preheater 3.
S3: Feeding said preheated wood chips from a preheater wood chips outlet 5b of thepreheater 3 to a defibrator wood chips inlet 9a of a connected defibrator 7 by a feed screwarrangement 11 which is connecting said preheater wood chips outlet 5b with said defibrator wood chips inlet 9a.
S4: Defibrating said wood chips in said defibrator 7.
S5: Returning steam from the defibrator 7 via the feed screw arrangement 11 to the preheater3 via a return steam pipe 23 which is extending between a return steam pipe first end 25a anda return steam pipe second end 25b and which is connecting the feed screw arrangement 11 and the preheater 3.
S6: I\/leasuring a feature in the return steam pipe 23 with a first sensor arrangement 31a at aposition which is closer to the return steam pipe first end 25a than the return steam pipesecond end 25b. Measuring a feature in the return steam pipe with a first sensor arrangement31a can be performed within a distance from the return steam pipe first end 25a which can be for example less than 1/4 or less than 1/6 of a total length (L) of the return steam pipe 23.
S7: I\/leasuring a feature in the defibrator system 1; 1' with a second sensor arrangement 31bwhich is provided either in a top portion 6a of said preheater 3 or at a position in connectionwith the return steam pipe 23 within a distance from the return steam pipe second end 25bwhich can be for example less than 1/4 or less than 1/6 ofa total length (L) ofthe return steam pipe 23.
Possibly the method further comprises the step of cleaning the return steam pipe if a measured feature indicates that the return steam pipe may be clogged.

Claims (26)

CLAll\/IS
1. A defibrator system for defibrating wood chips, said defibrator system (1;1') comprising: - a preheater(3) comprising a preheater wood chips inlet (5a) and a preheater woodchips outlet (5b); - a defibrator (7) comprising a defibrator wood chips inlet (9a) and a defibrator woodfibre outlet (9b); - a feed screw arrangement (11) which is connected to said preheater wood chipsoutlet (5b) and to said defibrator wood chips inlet (9a) and configured for feedingwood chips from the preheater wood chips outlet (5b) to the defibrator wood chipsinlet (9a); and - a return steam pipe arrangement (21) comprising a return steam pipe (23) whichis extending between a return steam pipe first end (25a) and a return steam pipesecond end (25b) and which is connected in the return steam pipe first end (25a)to the feed screw arrangement (11) and in the return steam pipe second end (25b)to the preheater (3), wherein said return steam pipe (23) is configured for transferring steam from the feed screw arrangement (11) to the preheater (3), wherein the return steam pipe arrangement (21) comprises a first sensor arrangement(31a) provided in connection with the return steam pipe (23) at a position which is closer to the return steam pipe first end (25a) than the return steam pipe second end (25b). Defibrator system according to c|aim 1, wherein the first sensor arrangement (31a) isprovided in connection with the return steam pipe (23) within a distance from thereturn steam pipe first end (25a) which is less than 1/4 ofa total length (L) ofthe return steam pipe (23). Defibrator system according to c|aim 1 or 2, wherein the defibrator system (1; 1') further comprises a second sensor arrangement (31b) which is provided either in connection with the return steam pipe (23) within a distance from the return steam pipe second end (25b) which is less than 1/4 of a total length (L) ofthe return steam pipe (23) or in a top portion (6a) of the preheater (3). Defibrator system according to claim 3, wherein the first sensor arrangement (31a) isprovided in connection with the return steam pipe first end (25a) and wherein thesecond sensor arrangement (31b) is provided in connection with the return steam pipe second end (25b). Defibrator system according to claim 3 or 4, wherein the first and second sensorarrangements (31a, 31b) comprises at least one same type of sensor for comparative measurements between the return steam pipe first and second ends (25a, 25b). Defibrator system according to any one of the preceding claims, wherein saidpreheater wood chips in|et (5a) is arranged in a top portion (6a) of said preheater (3)and said preheater wood chips out|et (5b) is arranged in a bottom portion (6b) of said preheater (3). Defibrator system according to any one of the preceding claims, wherein said return steam pipe second end (25b) is connected to a top portion (6a) of the preheater (3). Defibrator system according to any one of the preceding claims, wherein the feed screw arrangement (11) comprises a ribbon feed screw (15). Defibrator system according to any one of the preceding claims, wherein the feedscrew arrangement (11) comprises a plug feed screw (13) and a ribbon feed screw (15)connected to each other, wherein the plug feed screw (13) is connected to thepreheater woodchips out|et (5b) and is configured for feeding wood chips into theribbon feed screw (15), which is connected to the defibrator wood chips in|et (9a) andis configured for transferring the wood chips from the plug feed screw (13) to thedefibrator (7), wherein said ribbon feed screw (15) comprises a hollow centre allowingsteam to travel through the ribbon feed screw (15) in the opposite direction to a material feeding direction of the ribbon feed screw (15). 11 10. 11. 1
2. 1
3. Defibrator system according to any one ofthe preceding claims, wherein the first anda possible second sensor arrangement (31a, 31b) can comprise one or more of: a pressure sensor, a temperature sensor, a flow sensor and a speed sensor. A method for defibrating wood chips, said method comprising the steps of: - providing (S1) wood chips into a preheater (3) through a preheaterwood chips in|et(58): - preheating (S2) said wood ships in the preheater (3), - feeding (S3) said preheated wood chips from a preheater wood chips out|et (5b) ofthe preheater (3) to a defibrator wood chips in|et (9a) of a connected defibrator(7) by a feed screw arrangement (11) which is connecting said preheater woodchips out|et (5b) with said defibrator wood chips in|et (9a); - defibrating (S4) aid wood chips in said defibrator (7); and - returning steam (S5) from the defibrator (7) via the feed screw arrangement (11)to the preheater (3) via a return steam pipe (23) which is extending between areturn steam pipe first end (25a) and a return steam pipe second end (25b) and which is connecting the feed screw arrangement (11) and the preheater (3), wherein the method further comprises the step of measuring (S6) a feature in thereturn steam pipe (23) with a first sensor arrangement (31a) at a position which iscloser to the return steam pipe first end (25a) than the return steam pipe second end (25b). Method according to c|aim 11, wherein the step of measuring (S6) a feature in thereturn steam pipe (23) with a first sensor arrangement (31a) is performed within adistance from the return steam pipe first end (25a) which is less than 1/4 of a total length (L) of the return steam pipe (23). I\/|ethod according to c|aim 11 or 12, wherein the method further comprises the stepof measuring (S7) a feature in the defibrator system (1; 1') with a second sensor arrangement (31b) which is provided either in a top portion (6a) of said preheater (3) 12 1
4. 1
5. 1
6. 1
7. 1
8. or at a position in connection with the return steam pipe (23) within a distance fromthe return steam pipe second end (25b) which is less than 1/4 of a total length (L) of the return steam pipe (23). Method according to claim 13, wherein the step of measuring (S6) a feature in thereturn steam pipe (23) with a first sensor arrangement (31a) is performed in vicinity ofthe return steam pipe first end (25a) and the step of measuring (S7) a feature with asecond sensor arrangement (31b) is performed in vicinity of the return steam pipe second end (25b). Method according to claim 13 or 14, wherein the step of measuring (S6) a feature bya first sensor arrangement (31a) and measuring (S7) a feature by a second sensorarrangement (31b) comprises measuring at least one same feature by the first andsecond sensor arrangements (31a, 31b) for comparative measurements between the return steam pipe first and second ends (25a, 25b). Method according to any one of the claims 11-15, further comprising the step ofcleaning the return steam pipe (23) if a measured feature indicates that the return steam pipe may be clogged. Method according to any one of the claims 11-16, wherein the step of returning steam(S5) from the defibrator (7) via the feed screw arrangement (11) to the preheater (3)via a return steam pipe (23) is performed by returning steam to a top part (6a) of the preheater (3). Method according to any one ofthe claims 11-17, wherein the step of feeding (S3) saidpreheated wood chips from a preheater wood chips outlet (5b) to a defibrator woodchips inlet (9a) by a feed screw arrangement (11) comprises feeding the wood chips at least partly by a ribbon feed screw (15). 13 1
9. 20. 21. 22. 23. Method according to any one of the claims 11-18, wherein the step of measuring (S6,S7) a feature by the first and second sensor arrangements (31a, 31b) comprises measuring one or more of: a pressure, a temperature, a flow and a speed. A return steam pipe arrangement (21) comprising a return steam pipe (23) which isextending between a return steam pipe first end (25a) and a return steam pipe secondend (25b) and which is configured for being connectable in the return steam pipe firstend (25a) to a feed screw arrangement (11) provided for feeding wood chips betweena preheater (3) and a defibrator (7) in a defibrator system (1; 1') and in the returnsteam pipe second end (25b) to the preheater (3) of the defibrator system (1; 1'),wherein said return steam pipe (23) is configured for returning steam from thedefibrator (7) and the feed screw arrangement (11) to the preheater (3) and whereinthe return steam pipe arrangement (21) comprises a first sensor arrangement (31a)provided in connection with the return steam pipe (23) at a position which is closer to the return steam pipe first end (25a) than the return steam pipe second end (25b). Return steam pipe arrangement according to c|aim 20, wherein the first sensorarrangement (31a) is provided in connection with the return steam pipe (23) within adistance from the return steam pipe first end (25a) which is less than 1/4 of a total length (L) ofthe return steam pipe (23). Return steam pipe arrangement according to c|aim 20 or 21, wherein the return steampipe arrangement (21) further comprises a second sensor arrangement (31b) which isprovided in connection with the return steam pipe (23) within a distance from thereturn steam pipe second end (25b) which is less than 1/4 of a total length (L) of the return steam pipe (23). Return steam pipe arrangement according to c|aim 22, wherein the first sensorarrangement (31a) is provided in connection with the return steam pipe first end (25a)and wherein the second sensor arrangement (31b) is provided in connection with the return steam pipe second end (25b). 14 24. 25. 26. Return steam pipe arrangement according to claim 22 or 23, wherein the first andsecond sensor arrangements (31a, 31b) comprises at least one same type of sensor forcomparative measurements between the return steam pipe first and second ends (zsa, zsb). Return steam pipe arrangement according to any one of the claims 20-24, wherein thereturn steam pipe arrangement (21) comprises in the return steam pipe first end (25a)a first connection device (41a) configured for connection to a feed screw arrangement(11) in a defibrator system (1; 1') and in the return steam pipe second end (25b) asecond connection device (41b) configured for connection to the preheater (3) of the defibrator system (1; 1'). Return steam pipe arrangement according to any one of the claims 20-25, wherein the first and second sensor arrangements (31a, 31b) can comprise one or more of: a pressure sensor, a temperature sensor, a flow sensor and a speed sensor.
SE2050527A 2020-05-07 2020-05-07 A defibrator system and a return steam pipe SE2050527A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
SE2050527A SE2050527A1 (en) 2020-05-07 2020-05-07 A defibrator system and a return steam pipe
EP21800699.7A EP4146861A1 (en) 2020-05-07 2021-03-29 A system and method for defibrating wood chips, and a return steam pipe
PCT/SE2021/050276 WO2021225491A1 (en) 2020-05-07 2021-03-29 A system and method for defibrating wood chips, and a return steam pipe

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE2050527A SE2050527A1 (en) 2020-05-07 2020-05-07 A defibrator system and a return steam pipe

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Publication Number Publication Date
SE543739C2 SE543739C2 (en) 2021-07-06
SE2050527A1 true SE2050527A1 (en) 2021-07-06

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SE2050527A SE2050527A1 (en) 2020-05-07 2020-05-07 A defibrator system and a return steam pipe

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EP (1) EP4146861A1 (en)
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WO (1) WO2021225491A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB515944A (en) * 1937-06-12 1939-12-19 Hermann Basler Apparatus for disintegrating vegetable fibrous materials
US4082233A (en) * 1975-06-04 1978-04-04 Rolf Bertil Reinhall Disc refiner having means for removing gaseous media from pulp stock
SE417130B (en) * 1979-08-22 1981-02-23 Bahco Ventilation Ab Method for recovering valuable vapour by refining of fibre material as well as device for working the method
GB1600570A (en) * 1977-06-08 1981-10-21 Beloit Corp Method and apparatus for thermomechanical pulping
CA1125077A (en) * 1979-12-04 1982-06-08 Erkki Valkama Procedure and apparatus for preparing groundwood mechanically from wood chips

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB515944A (en) * 1937-06-12 1939-12-19 Hermann Basler Apparatus for disintegrating vegetable fibrous materials
US4082233A (en) * 1975-06-04 1978-04-04 Rolf Bertil Reinhall Disc refiner having means for removing gaseous media from pulp stock
GB1600570A (en) * 1977-06-08 1981-10-21 Beloit Corp Method and apparatus for thermomechanical pulping
SE417130B (en) * 1979-08-22 1981-02-23 Bahco Ventilation Ab Method for recovering valuable vapour by refining of fibre material as well as device for working the method
CA1125077A (en) * 1979-12-04 1982-06-08 Erkki Valkama Procedure and apparatus for preparing groundwood mechanically from wood chips

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SE543739C2 (en) 2021-07-06
WO2021225491A1 (en) 2021-11-11

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