CA2012251A1 - Twin wire former - Google Patents
Twin wire formerInfo
- Publication number
- CA2012251A1 CA2012251A1 CA002012251A CA2012251A CA2012251A1 CA 2012251 A1 CA2012251 A1 CA 2012251A1 CA 002012251 A CA002012251 A CA 002012251A CA 2012251 A CA2012251 A CA 2012251A CA 2012251 A1 CA2012251 A1 CA 2012251A1
- Authority
- CA
- Canada
- Prior art keywords
- forming
- screen
- wire former
- twin wire
- former according
- 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.)
- Abandoned
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F9/00—Complete machines for making continuous webs of paper
- D21F9/003—Complete machines for making continuous webs of paper of the twin-wire type
Landscapes
- Paper (AREA)
- Electrostatic Charge, Transfer And Separation In Electrography (AREA)
- Inks, Pencil-Leads, Or Crayons (AREA)
Abstract
ABSTRACT
Twin wire former having a stuff discharge opening for the twin screen in the region of a preferably open forming roller, comprising at least one stationary forming element (22;22') located below the lower screen (12) and comprising above the upper screen (18) at a spacing therefrom and proceeding from the forming roller (10) across the forming zone (D-E) a water guide element (25;25') is provided and the forming rails contact the upper screen (18) in the region of a forming element (22;22').
Twin wire former having a stuff discharge opening for the twin screen in the region of a preferably open forming roller, comprising at least one stationary forming element (22;22') located below the lower screen (12) and comprising above the upper screen (18) at a spacing therefrom and proceeding from the forming roller (10) across the forming zone (D-E) a water guide element (25;25') is provided and the forming rails contact the upper screen (18) in the region of a forming element (22;22').
Description
2012ZSl TWIN WIRE FORMER
The invention relates to a twin wire former having an upper screen and a lower screen, a leading forming roller, ir. particular an open roller, arranged at the start of a forming zone, at least one forming element arranged behind the forming roller and abutting the lower screen, a guide element extending approximately from the start of the forming zone and arranged it the area of the forming roller, the forming roller being partially embraced by the twin screen and at least one dewatering rail arranged above the upper screen.
Such a twin wire former, but with preliminary dewatering, is known from DE-OA-3123132. The leading forming roller is arranged above the upper screen as an open forming roller and flings water obliquely upwards without however giving rise to any driving effect for secondary jets which occur in the region of the dewatering rails, since here the jets run approximately parallel with substantially uniform speed. On the lower screen, in the movement direction of the twin screen, behind the forming roller, there lies a further forming roller opposite which are arranged the dewatering rails without contact with the upper screen.
Other twin wire formers which operate with an upper leading forming roller and in the region of the upper screen, have dewatering rails in contact therewith, operate with suction chambers which are arranged between the dewatering rails in order to extract the water laterally from the device.
The invention relates to a twin wire former having an upper screen and a lower screen, a leading forming roller, ir. particular an open roller, arranged at the start of a forming zone, at least one forming element arranged behind the forming roller and abutting the lower screen, a guide element extending approximately from the start of the forming zone and arranged it the area of the forming roller, the forming roller being partially embraced by the twin screen and at least one dewatering rail arranged above the upper screen.
Such a twin wire former, but with preliminary dewatering, is known from DE-OA-3123132. The leading forming roller is arranged above the upper screen as an open forming roller and flings water obliquely upwards without however giving rise to any driving effect for secondary jets which occur in the region of the dewatering rails, since here the jets run approximately parallel with substantially uniform speed. On the lower screen, in the movement direction of the twin screen, behind the forming roller, there lies a further forming roller opposite which are arranged the dewatering rails without contact with the upper screen.
Other twin wire formers which operate with an upper leading forming roller and in the region of the upper screen, have dewatering rails in contact therewith, operate with suction chambers which are arranged between the dewatering rails in order to extract the water laterally from the device.
2 2~2~5 The invention is based on the object of creating a twin wire former of the type initially defined in which, by a simpler and more compact construction, gentler and better dewatering can be achieved within the forming zone in such manner that without adversely affecting the fibre retention, the forming process can be improved and in particular can be homogenized.
This object is achieved according to the invention in that the forming element, which is a stationary forming element, has a flatter curvature than the leading forming roller, the dewatering rails are forming rails effective in forming and as such are supported by the upper screen, and a stuff-supplying nozzle is arranged in front of the position where the upper screen and the lower screen run together to form the twin screen.
y this solution, in conjunction with the forming roller the water jet which is spun away there, is diverted without difficulty and without the need for a suction chamber along the water guide element in the end region of the forming zone. In this connection, this water guide element can be optimally curved, preferably relatively flat, in adaptation to the flow conditions, i.e. it can be directed approximately along the screen direction.
The spun off water jet has a driving effect in such manner that by the optimal alignment and optimal guidance of the spun water jet, as drive jet, a carrier effect is produced for the secondary jets in the region of the dewatering rails. This applies in particular if energy loss takes place in the region of the forming rails for the water extraction.
Z~l225~
By spinning off the water in the region of the leading forming roller upon the introduction of stuff which has not been subject to preliminary dewatering, and by the directly adjoining stationary forming element in the region of the lower screen and the subsequent dewatering in the region of the forming rail, optimally graduated dewatering takes place in such manner that the pressure pulse on the suspension between the screens can be increased with increasing look~through.
By the possibility of omitting the suction chambers, closer staggering of the forming rails is possible. This means higher frequency of the stuff and this results in more uniform look-through.
The look-through is also improved in that the dewatering rails acting as forming rails lie on the upper screen and in particular press thereon so that deflection of the twin screen takes place.
If according to an advantageous further development the forming rails are arranged in the rear half and in particular in the final third of the forming zone, impact of the vigorous driving jet onto the forming rails behind the forming roller is prevented.
It is an essential advantage of the invention that the stuff which has not been subject to preliminary dewatering is fed to the converging twin screen and then is dewatered in the wrapping region of the double screen around the leading forming roller and thus a very vigorous driving jet is produced.
- 4 2ol22s~
If the direction of application of the stuff from the charging nozzle is approximately the direction of the spun off driving jet, then the resulting stronger driving jet has from the start the effect that the secondary jets which are weak, in particular upon start up are carried al~g. This means that in the region of the forming rails water which arises is steadily channelled along without problems.
The angle by which the twin screen embraces the forming roller is preferably 5 to 120 and in particular approximately 20. This embracing affects the strength of the driving jet. The driving jet thickness can be between 2 and 19 my, according to a web speed of 300 to 2000 m/min. In this lS connection, normally the driving jet amounts to 40%
of the amount which is dewatered solely in the upper screen.
Preferably, two or three, and in particulal three forming rails are provided.
The forming rails can be inclined in the direction of the screen movement and in this connection make an angle to the screen of 20 to 90 and in particular about 37. This affects the transition of the secondary jets along the forming rails into the main driving jet.
Preferably, the forming rails are arranged at spacing of less than 200 mm in order to achieve the best effect.
The water guide element can be arranged as the inner contour of an upper trough, to first of all rise slightly proceeding from the forming roller, then proceed substantially horizontally and thereafter to fall again to the end of the forming zone, this guide , element being slightly curved as a whole so that the water jets make contact as a film flow as a result of centrifugal force.
In addition to careful dewatering, in particular improvement of the look-through (Egoutteur effect) and without the retention, pinholes and the L/Q ratio being affected disadvantageously.
With screen speeds below 800 m/min, supplementary vacuum chambers can be provided.
The forming roller can be constructed to function also as a suction roller so that the slight dewatering pressure of the outer screen occurring at high rota: :,dl speeds can be compensated by vacuum.
The expressions "leading" and "trailing" relate to the direction of motion of the screens, and in particular of the twin screen.
Further advantageous constructions appear from the sub-claims.
The invention will be described in more detail in the following with reference to an exemplary embodiment illustrated purely schematically in the drawings, in which:
Fig. l is a schematic representation of a twin wire former as a part of a paper manufacturing machine;and Fig. 2 is a partial view of forming rails pressing on the upper screen.
6 2ol22sl On the left of Fig. 1, a forming roller 10 is schematically illustrated and in fact is constructed as a so-called open forming roller in the periphery of which chambers are formed. Over this forming roller, a lower screen 12 is fed to a suspension charging gap 14, which is formed from the lower screen 12 fed around the forming roller 10 and the upper screen 18 fed from a deflection roller 16, both screens coming together at a position D and thereafter forming a double screen. A stuff charging nozzle 20 is allocated to this charging gap 14.
In the illustrated embodiment, the double screen embraces the forming roller 10 with an angle alpha, which lies between 5 and 120, in the illustrated example proximately 20. The double screen runs at it right-hand end in the drawing around a rear forming roller 5. This forming roller 5 can be implemented as a suction roller, as a full roller and/or can be grooved in the peripheral direction. The lower screen 12 carrying the fibre layer departs fram this forming roller 5 at a position E, so that between the positions D and E the forming zone is formed. below the lower screen 12 are located, in the region of the double guidance of lower screen 12 and upper screen 18 in this exemplary embodiment, two forming shoes 22 and 22' with vacuum chambers. These forming shoes support the lower screen with mutually spaced lands 24.
Normally, the screen moves with high speed. Since the stuff discharged from the nozzle 20 contains in addition to fibres and a filling material up to 99 water, violent dewatering takes place in the wrap around region to the effect that a drive jet A is 7 20~22~1, produced. This drive jet A is spun off approximately tangentially of the forming roller. Since the forming roller is constructed as an open forming roller provided with peripheral chambers, also a S water jet A' is formed in the peripheral direction in order simultaneously to divert a portion of the water downwardly from the stuff.
The extent of wrap around of the forming roller substantially affects the force and the amount of water of the drive jet A, drive jet thicknesses of 2 to 19 mm being attainable, according to the web speed of 300 to 2000 m/min. The drive jet amounts in this connection to about an amount greater than or equal to 40% of the amount which is dewatered solely in the upper screen.
The drive jet A is guided as a main jet by a guide element 25 and 25' consisting here of two sections, which surrounds the entire forming zone, in that proceeding from the forming roller 10 to the twin screen the distance increases in the direction to the position E. This means in this exemplary embodiment, in which also the twin screen rises slightly in the forming zone, that also the guide element first rises and then falls again towards the end, it being possible also to provide a substantially horizontal section. From the drawing, it can be seen that the curved passage of the guide element is relatively flat.
The section 25' of the guide element is pivotal upwardly via a rod 31 about a bearing axis 33, in order to make accessible the region in which the forming rails are located for cleaning purposes.
In the representation in Fig. 1, in the two halves of the forming zone, proceeding approximately 8 2ol22~l from the centre, preferably however in the last third, three forming rails 26,26',26'' are located, it also being possible to provide e.g. only two or more rails. These rails lie with their lower end, preferably outside the lands 24, on the upper screen and thus on the twin screen. Guide surfaces 27,27~, 27'' abut the forming rails, and are arranged at the illustrated angle to the screen. This angle lies in the range of 20 to 90, preferably however in the region of 3~.
The drive jet has sufficient kinetic energy that the secondary jets B,C and C' are carried along in the region of the forming rails 26,26' and 26'' and subsequently are guided into a deflection trough 30.
In order that the forming rails are arranged to be set back relatively far from the forming roller, e.g. from the end of the first third of the forming zone D-E, the drive jet cannot impact directly on the rails, which disturbs the flow conditions and thus leads to careful and intensive dewatering in particular in the region of the rails. If the number of forming rails is equal to or larger than two, and the spacing is smaller than 200 mm, a very good effect, both in respect of dewatering and also in respect of the formation of the fibre texture can be achieved. Discharge of the water extracted from the upper screen takes place at a location where this is less disturbing and also more space is available.
Preferably, for improving the look-through of the fillers, the forming rails B,C and C' lie on the upper screen and are in this connection pressed onto the upper surface in such manner that the twin screen is deflected, either to the direct vicinity of the I' 35 forming shoe or between the lands 24 of the forming g Zo~225l shoes 22,22'. The deflection is up to lO mm, preferably 4 mm. In this connection reference may be made to Fig. 2.
As a result of the deflection of the water onto the forming rails, speed reduction takes place so that a speed difference occurs according to amount and direction between the main jet A and the secondary jets B,C,C'. The suction resulting from this supplements the dewatering without the need to 1 o apply an expensive vacuum at screen above about 800m/min. Fundamentally, the kinetic energy of the main jet A is thus exploited, where a extent that a difference in speed between this and the secondary jets exists.
It is important to note that in the forming region of the paper machine it is desired to achieve graduated effects on the web in such manner that with increasing dewateri~g the size of the pressure pulse increases.
, .
This object is achieved according to the invention in that the forming element, which is a stationary forming element, has a flatter curvature than the leading forming roller, the dewatering rails are forming rails effective in forming and as such are supported by the upper screen, and a stuff-supplying nozzle is arranged in front of the position where the upper screen and the lower screen run together to form the twin screen.
y this solution, in conjunction with the forming roller the water jet which is spun away there, is diverted without difficulty and without the need for a suction chamber along the water guide element in the end region of the forming zone. In this connection, this water guide element can be optimally curved, preferably relatively flat, in adaptation to the flow conditions, i.e. it can be directed approximately along the screen direction.
The spun off water jet has a driving effect in such manner that by the optimal alignment and optimal guidance of the spun water jet, as drive jet, a carrier effect is produced for the secondary jets in the region of the dewatering rails. This applies in particular if energy loss takes place in the region of the forming rails for the water extraction.
Z~l225~
By spinning off the water in the region of the leading forming roller upon the introduction of stuff which has not been subject to preliminary dewatering, and by the directly adjoining stationary forming element in the region of the lower screen and the subsequent dewatering in the region of the forming rail, optimally graduated dewatering takes place in such manner that the pressure pulse on the suspension between the screens can be increased with increasing look~through.
By the possibility of omitting the suction chambers, closer staggering of the forming rails is possible. This means higher frequency of the stuff and this results in more uniform look-through.
The look-through is also improved in that the dewatering rails acting as forming rails lie on the upper screen and in particular press thereon so that deflection of the twin screen takes place.
If according to an advantageous further development the forming rails are arranged in the rear half and in particular in the final third of the forming zone, impact of the vigorous driving jet onto the forming rails behind the forming roller is prevented.
It is an essential advantage of the invention that the stuff which has not been subject to preliminary dewatering is fed to the converging twin screen and then is dewatered in the wrapping region of the double screen around the leading forming roller and thus a very vigorous driving jet is produced.
- 4 2ol22s~
If the direction of application of the stuff from the charging nozzle is approximately the direction of the spun off driving jet, then the resulting stronger driving jet has from the start the effect that the secondary jets which are weak, in particular upon start up are carried al~g. This means that in the region of the forming rails water which arises is steadily channelled along without problems.
The angle by which the twin screen embraces the forming roller is preferably 5 to 120 and in particular approximately 20. This embracing affects the strength of the driving jet. The driving jet thickness can be between 2 and 19 my, according to a web speed of 300 to 2000 m/min. In this lS connection, normally the driving jet amounts to 40%
of the amount which is dewatered solely in the upper screen.
Preferably, two or three, and in particulal three forming rails are provided.
The forming rails can be inclined in the direction of the screen movement and in this connection make an angle to the screen of 20 to 90 and in particular about 37. This affects the transition of the secondary jets along the forming rails into the main driving jet.
Preferably, the forming rails are arranged at spacing of less than 200 mm in order to achieve the best effect.
The water guide element can be arranged as the inner contour of an upper trough, to first of all rise slightly proceeding from the forming roller, then proceed substantially horizontally and thereafter to fall again to the end of the forming zone, this guide , element being slightly curved as a whole so that the water jets make contact as a film flow as a result of centrifugal force.
In addition to careful dewatering, in particular improvement of the look-through (Egoutteur effect) and without the retention, pinholes and the L/Q ratio being affected disadvantageously.
With screen speeds below 800 m/min, supplementary vacuum chambers can be provided.
The forming roller can be constructed to function also as a suction roller so that the slight dewatering pressure of the outer screen occurring at high rota: :,dl speeds can be compensated by vacuum.
The expressions "leading" and "trailing" relate to the direction of motion of the screens, and in particular of the twin screen.
Further advantageous constructions appear from the sub-claims.
The invention will be described in more detail in the following with reference to an exemplary embodiment illustrated purely schematically in the drawings, in which:
Fig. l is a schematic representation of a twin wire former as a part of a paper manufacturing machine;and Fig. 2 is a partial view of forming rails pressing on the upper screen.
6 2ol22sl On the left of Fig. 1, a forming roller 10 is schematically illustrated and in fact is constructed as a so-called open forming roller in the periphery of which chambers are formed. Over this forming roller, a lower screen 12 is fed to a suspension charging gap 14, which is formed from the lower screen 12 fed around the forming roller 10 and the upper screen 18 fed from a deflection roller 16, both screens coming together at a position D and thereafter forming a double screen. A stuff charging nozzle 20 is allocated to this charging gap 14.
In the illustrated embodiment, the double screen embraces the forming roller 10 with an angle alpha, which lies between 5 and 120, in the illustrated example proximately 20. The double screen runs at it right-hand end in the drawing around a rear forming roller 5. This forming roller 5 can be implemented as a suction roller, as a full roller and/or can be grooved in the peripheral direction. The lower screen 12 carrying the fibre layer departs fram this forming roller 5 at a position E, so that between the positions D and E the forming zone is formed. below the lower screen 12 are located, in the region of the double guidance of lower screen 12 and upper screen 18 in this exemplary embodiment, two forming shoes 22 and 22' with vacuum chambers. These forming shoes support the lower screen with mutually spaced lands 24.
Normally, the screen moves with high speed. Since the stuff discharged from the nozzle 20 contains in addition to fibres and a filling material up to 99 water, violent dewatering takes place in the wrap around region to the effect that a drive jet A is 7 20~22~1, produced. This drive jet A is spun off approximately tangentially of the forming roller. Since the forming roller is constructed as an open forming roller provided with peripheral chambers, also a S water jet A' is formed in the peripheral direction in order simultaneously to divert a portion of the water downwardly from the stuff.
The extent of wrap around of the forming roller substantially affects the force and the amount of water of the drive jet A, drive jet thicknesses of 2 to 19 mm being attainable, according to the web speed of 300 to 2000 m/min. The drive jet amounts in this connection to about an amount greater than or equal to 40% of the amount which is dewatered solely in the upper screen.
The drive jet A is guided as a main jet by a guide element 25 and 25' consisting here of two sections, which surrounds the entire forming zone, in that proceeding from the forming roller 10 to the twin screen the distance increases in the direction to the position E. This means in this exemplary embodiment, in which also the twin screen rises slightly in the forming zone, that also the guide element first rises and then falls again towards the end, it being possible also to provide a substantially horizontal section. From the drawing, it can be seen that the curved passage of the guide element is relatively flat.
The section 25' of the guide element is pivotal upwardly via a rod 31 about a bearing axis 33, in order to make accessible the region in which the forming rails are located for cleaning purposes.
In the representation in Fig. 1, in the two halves of the forming zone, proceeding approximately 8 2ol22~l from the centre, preferably however in the last third, three forming rails 26,26',26'' are located, it also being possible to provide e.g. only two or more rails. These rails lie with their lower end, preferably outside the lands 24, on the upper screen and thus on the twin screen. Guide surfaces 27,27~, 27'' abut the forming rails, and are arranged at the illustrated angle to the screen. This angle lies in the range of 20 to 90, preferably however in the region of 3~.
The drive jet has sufficient kinetic energy that the secondary jets B,C and C' are carried along in the region of the forming rails 26,26' and 26'' and subsequently are guided into a deflection trough 30.
In order that the forming rails are arranged to be set back relatively far from the forming roller, e.g. from the end of the first third of the forming zone D-E, the drive jet cannot impact directly on the rails, which disturbs the flow conditions and thus leads to careful and intensive dewatering in particular in the region of the rails. If the number of forming rails is equal to or larger than two, and the spacing is smaller than 200 mm, a very good effect, both in respect of dewatering and also in respect of the formation of the fibre texture can be achieved. Discharge of the water extracted from the upper screen takes place at a location where this is less disturbing and also more space is available.
Preferably, for improving the look-through of the fillers, the forming rails B,C and C' lie on the upper screen and are in this connection pressed onto the upper surface in such manner that the twin screen is deflected, either to the direct vicinity of the I' 35 forming shoe or between the lands 24 of the forming g Zo~225l shoes 22,22'. The deflection is up to lO mm, preferably 4 mm. In this connection reference may be made to Fig. 2.
As a result of the deflection of the water onto the forming rails, speed reduction takes place so that a speed difference occurs according to amount and direction between the main jet A and the secondary jets B,C,C'. The suction resulting from this supplements the dewatering without the need to 1 o apply an expensive vacuum at screen above about 800m/min. Fundamentally, the kinetic energy of the main jet A is thus exploited, where a extent that a difference in speed between this and the secondary jets exists.
It is important to note that in the forming region of the paper machine it is desired to achieve graduated effects on the web in such manner that with increasing dewateri~g the size of the pressure pulse increases.
, .
Claims (20)
1. Twin wire former comprising:
- an upper screen (18) and a lower screen (12), - a leading forming roller (10) arranged at the beginning of the forming zone (D-E), in particular an open forming roller (10), - at least one forming element (22;22') arranged behind the forming roller (10) in contact with the lower screen (12), - a water guide element (25;25') arranged in the region of the forming roller (10) approximately at the start of the forming zone (D/E), - a partial wrap around of the forming roller (10) by the twin screen and - at least one dewatering rail (26;26';26'') arranged above the upper screen (18), characterized in that - the forming element (22;22'), as a stationary forming element, has a flatter curvature than the leading forming roller (10), - the dewatering rails (26;26';26'') are forming rails effective in forming and as such are in contact with the upper screen, and - before the position where the upper screen (18) and the lower screen (12) come together to form the double screen, a stuff discharge nozzle (20) is arranged (for stuff which is not subject to preliminary dewatering).
- an upper screen (18) and a lower screen (12), - a leading forming roller (10) arranged at the beginning of the forming zone (D-E), in particular an open forming roller (10), - at least one forming element (22;22') arranged behind the forming roller (10) in contact with the lower screen (12), - a water guide element (25;25') arranged in the region of the forming roller (10) approximately at the start of the forming zone (D/E), - a partial wrap around of the forming roller (10) by the twin screen and - at least one dewatering rail (26;26';26'') arranged above the upper screen (18), characterized in that - the forming element (22;22'), as a stationary forming element, has a flatter curvature than the leading forming roller (10), - the dewatering rails (26;26';26'') are forming rails effective in forming and as such are in contact with the upper screen, and - before the position where the upper screen (18) and the lower screen (12) come together to form the double screen, a stuff discharge nozzle (20) is arranged (for stuff which is not subject to preliminary dewatering).
2. Twin wire former according to claim 1, characterized in that guide surfaces (27;27';27'') abut the forming rails (26;26';26''), which guide surfaces end at a spacing before the water guide element (25,25').
3. Twin wire former according to claim 1, characterized in that the stationary forming element (22;22') is constructed in a manner known per se as a forming shoe with spaced lands (24;24') arranged transversely of the screen motion direction.
4. Twin screen former according to claim 1, characterized in that the forming rails (26;26';26'') press on the double screen (12,18).
5. Twin wire former according to claim 1, characterized in that the forming rails (26;26';26'') press on the double screen (12,18) in such manner that this experiences deflection.
6. Twin wire former according to claim 1 and 3, characterized in that the forming rails (26;26';26'') contact the upper screen between the lands (24;24') with the forming shoe.
7. Twin wire former according to claim 1, characterized in that the leading forming roller (10) is arranged beneath the lower screen (12).
8. Twin wire former according to claim 7, characterized in that the wrap around of the forming roller (10) by the double screen (12,18) is provided to a vertical line through the axis of the forming roller (10) in the leading half of the forming roller (10).
9. Twin wire former according to one of claims 1 to 8, characterized in that at the end of the forming zone (D-E) a rear forming roller (5) is arranged which likewise is located beneath the lower screen (12).
10. Twin wire former according to one of claims 1 to 9, characterized in that the deflection of the double screen under pressure from the forming rails (26;26';26") is up to 10 mm and in particular 4 mm.
11. Twin wire former according to one of claims 1 to 10, characterized in that the position of the departure point (D) of the twin screen (12,18) from the leading forming roller (10) in the event that the forming roller lies beneath the lower screen, lies in the upper leading quadrant, that is to say preferably in the angle section between 310° and 360°.
12. Twin wire former according to any one of claims 1 to 11, characterized in that the forming rails (26;26';26") are arranged in the two latter thirds, and in particular in the last third of the forming zone (D-E).
13. Twin wire former according to any one of claims 1 to 12, characterized in that the twin screen (12,18) embraces the forming roller (10) with an angle alpha of 5° to 120°, and in particular approximately 20°.
14. Twin wire former according to any one of claims 1 to 13, characterized in that two or three forming rails (26;26';26'') are provided.
15. Twin wire former according to claim 2, characterized in that the guide surfaces (27;27';27") are inclined in the direction of the screen motion and in this connection assume an angle of 20° to 90°, and in particular approximately 37°, to the screen.
16. Twin wire former according to any one of claims 1 to 15, characterized in that the forming rails (26;26';26'') are arranged along the double screen at a spacing of less than 200 mm.
17. Twin wire former according to any one of claims 1 to 16, characterized in that the water guide element (25;25') is arranged initially to rise slightly and then is arranged substantially horizontally and thereafter falls again.
18. Twin wire former according to any one of claims 1 to 17, characterized in that the water guide element (25;25') consists of a plurality of sections which are positionally variable for changing the overall length of the guide surface.
19. Twin wire former according to any one of claims 1 to 17, characterized in that a section of the water guide element (25;25'), which covers the forming rails (26;26';26'') can be pivoted away.
20. Twin wire former according to any one of claims 1 to 19, characterized in that the forming roller (10) is constructed as a suction roller.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3910892.9 | 1989-04-04 | ||
| DE3910892A DE3910892A1 (en) | 1989-04-04 | 1989-04-04 | DOUBLE SCREEN FORMER |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2012251A1 true CA2012251A1 (en) | 1990-10-04 |
Family
ID=6377839
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002012251A Abandoned CA2012251A1 (en) | 1989-04-04 | 1990-03-15 | Twin wire former |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0391025B1 (en) |
| AT (1) | ATE111990T1 (en) |
| CA (1) | CA2012251A1 (en) |
| DE (1) | DE3910892A1 (en) |
| ES (1) | ES2058612T3 (en) |
| FI (1) | FI900730A7 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5300196A (en) * | 1991-05-29 | 1994-04-05 | Voith Gmbh | Twin-wire former with frame for a paper making machine |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI83977C (en) * | 1989-11-06 | 1991-09-25 | Valmet Paper Machinery Inc | Gap formers in paper machine |
| DE4037017C2 (en) * | 1990-11-20 | 1994-12-08 | Escher Wyss Gmbh | Wet part of a twin wire paper machine |
| JP2808491B2 (en) * | 1990-12-19 | 1998-10-08 | 三菱重工業株式会社 | Twin wire former for paper machine |
| FI93032C (en) * | 1991-03-15 | 1995-02-10 | Valmet Paper Machinery Inc | Two-wire web forming section of a paper machine |
| DE10106731A1 (en) * | 2001-02-14 | 2002-08-22 | Voith Paper Patent Gmbh | Twin-wire former for the production of a fibrous web from a fibrous suspension |
| DE102010042604A1 (en) | 2010-10-19 | 2012-04-19 | Voith Patent Gmbh | Sheet forming unit for producing a material web and method for operating the sheet forming unit |
| FI11620U1 (en) * | 2016-12-08 | 2017-04-12 | Valmet Technologies Oy | Viral part, especially modernized viral part |
| CN107460760B (en) * | 2017-09-13 | 2019-03-01 | 长兴恒大电子材料有限公司 | A kind of heat transfer paper production and processing technology |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1294075A (en) * | 1969-02-13 | 1972-10-25 | Beloit Corp | Improved forming arrangement |
| BE757784R (en) * | 1969-10-22 | 1971-04-01 | Beloit Corp | IMPROVED FORMING DEVICE |
| SE372300B (en) * | 1970-01-26 | 1974-12-16 | Enso Gutzeit Oy | |
| DE2826158B2 (en) * | 1978-06-15 | 1980-07-24 | J.M. Voith Gmbh, 7920 Heidenheim | Wire section for a machine for the production of fiber webs |
| WO1982002910A1 (en) * | 1981-02-28 | 1982-09-02 | Zag Heinz | Device for continuously dehydrating a fiber web |
| DE3138133C2 (en) * | 1981-09-04 | 1986-03-06 | Sulzer-Escher Wyss GmbH, 7980 Ravensburg | Dewatering unit for Fourdrinier paper machines |
| FI75376C (en) * | 1982-04-30 | 1988-06-09 | Valmet Oy | FORMNINGSSKO FOER FORMARE I PAPPERSMASKIN. |
| FI840246A7 (en) * | 1984-01-20 | 1985-07-21 | Valmet Oy | FOERFARANDE OCH ANORDNING VID FORMNING AV PAPPERSBANA. |
| FI77281C (en) * | 1987-06-18 | 1989-02-10 | Valmet Paper Machinery Inc | HYBRIDFORMARE FOER EN PAPPERSMASKIN. |
-
1989
- 1989-04-04 DE DE3910892A patent/DE3910892A1/en active Granted
-
1990
- 1990-01-19 AT AT90101039T patent/ATE111990T1/en active
- 1990-01-19 ES ES90101039T patent/ES2058612T3/en not_active Expired - Lifetime
- 1990-01-19 EP EP90101039A patent/EP0391025B1/en not_active Expired - Lifetime
- 1990-02-14 FI FI900730A patent/FI900730A7/en not_active IP Right Cessation
- 1990-03-15 CA CA002012251A patent/CA2012251A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5300196A (en) * | 1991-05-29 | 1994-04-05 | Voith Gmbh | Twin-wire former with frame for a paper making machine |
| US5498316A (en) * | 1991-05-29 | 1996-03-12 | J. M. Voith Gmbh | Twin wire former for a paper making machine |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0391025A1 (en) | 1990-10-10 |
| ES2058612T3 (en) | 1994-11-01 |
| FI900730A0 (en) | 1990-02-14 |
| DE3910892C2 (en) | 1993-09-09 |
| DE3910892A1 (en) | 1990-10-11 |
| ATE111990T1 (en) | 1994-10-15 |
| EP0391025B1 (en) | 1994-09-21 |
| FI900730A7 (en) | 1990-10-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3994774A (en) | Twin-wire paper machine adjustable to single-wire machine | |
| EP1337707B1 (en) | Impingement drying unit and a dryer section | |
| CA1299865C (en) | Method and apparatus in a paper machine single-wire drying group | |
| FI112680B (en) | Apparatus for the manufacture of multilayer paper or board | |
| FI84734B (en) | DOUBLE VAPOR FORM PAPER MACHINE. | |
| US6159341A (en) | Wire part for forming a multi-ply fiber web | |
| EP0373133A2 (en) | Method and device in the formation of a paper or board web | |
| JPH02191792A (en) | Paper forming method and apparatus | |
| FI77281C (en) | HYBRIDFORMARE FOER EN PAPPERSMASKIN. | |
| CA2012251A1 (en) | Twin wire former | |
| US4557802A (en) | Apparatus for affecting a web drained on a wire | |
| CA1168492A (en) | Apparatus for continuously dewatering of a fibrous web | |
| US3944464A (en) | Forming section for twin-wire papermaking machine | |
| US3996098A (en) | Twin-wire paper machine with common wire path controls | |
| CA1183710A (en) | Longitudinal wire papermaking machine | |
| FI91788B (en) | Two-wire web forming section of a paper machine | |
| GB2096199A (en) | Double wire paper-making machine | |
| US5019214A (en) | Twin-wire former for the production of a web of paper | |
| US5225043A (en) | Twin wire former with water guide element over the forming zone | |
| JP2722192B2 (en) | Web forming equipment | |
| US3941651A (en) | Twin-wire paper manufacturing machines | |
| US4919760A (en) | Web former for a paper machine | |
| FI68275B (en) | BANFORMNINGSFOERFARANDE VID EN UPPTAGNINGS- OCH TORKNINGSMASKIN FOER CELLULOSA | |
| JP2001515153A (en) | Multilayer web forming method and apparatus and multilayer paper or paperboard product formed thereby | |
| CA2150032C (en) | Double-wire former for a paper-making machine |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |