CA2325990C - A trailing element device - Google Patents
A trailing element device Download PDFInfo
- Publication number
- CA2325990C CA2325990C CA002325990A CA2325990A CA2325990C CA 2325990 C CA2325990 C CA 2325990C CA 002325990 A CA002325990 A CA 002325990A CA 2325990 A CA2325990 A CA 2325990A CA 2325990 C CA2325990 C CA 2325990C
- Authority
- CA
- Canada
- Prior art keywords
- downstream
- downstream portion
- upstream
- locking
- relative
- 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 - Fee Related
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F1/00—Wet end of machines for making continuous webs of paper
- D21F1/02—Head boxes of Fourdrinier machines
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F1/00—Wet end of machines for making continuous webs of paper
- D21F1/02—Head boxes of Fourdrinier machines
- D21F1/028—Details of the nozzle section
Abstract
A trailing element device is disclosed for controlling the magnitude and sca le of turbulence of stock flowing through a slice chamber (12) of a headbox of a papermaking machine. The device includes an upstream member (14), the upstream member including a locking portion (16) for locking the upstream member (14) relative to an upstream en d (18) of the slice chamber. The upstream member (14) also includes a downstream portion (20) disposed within the slice chamber and downstream relative to the locking portion. An intermediate portion is disposed between the locking portion and the downstream portion (22) and a downstream member (24) is disposed downstream relative to the downstream portion. The downstream member (24) is fusion welded to the downstream portion (22).
Description
WO 98/51856 PCT/US98l05663 TITLE: A TRAILING ELEMENT DEVICE
BACKGROUND OF THE iNVENTION
Field of the Invention The present invention relates to a trailing element device for controlling the magnitude and scale of turbulence of stock flowing through a slice chamber. More specifically, the present invention relates to a trailing element device for controlling the magnitude and scale of turbulence of stock flowing through a slice chamber of a headbox of a papermaking machine.
lnfgrmation Disciosure Statement In the papermaking art pressurized stock is ejected from a headbox onto a moving fourdrinier wire so that as water is drained from the stock through the fourdrinier wire, a web of paper is formed on the wire.
In order to control the magnitude and scale of turbulence of the stock fiowing "through the headbox and particularly the slice chamber thereof, trailing elements or CONVERFLO* sheets are anchored at the upstream end of the slice chamber. The arrangement is such that as the stock flows through the slice chamber, the trailing elements are freely suspended within the stock flow being anchored only at the upstream end thereof.
The aforementioned trailing elements are known In the art as CONVERFLO sheets. CONVERFLO is a common law trademark of Beloit Technoiogies, Inc.
* Trade-mark Typically, the trailing elements are fabricated from Lexan* sheets and the Lexan sheets are bonded together to form a composite sheet by means of chemical bonding agents. One type of bonding agent or solvent used for joining the Lexan sheets together is methylene chloride. However, methyiene chloride is known to be a carcinogen. Consequently, it is desirable to eliminate the use of the aforementioned bonding agents.
Moreover, aithough the use,of inethyfene chloride has been successful in providing an adequate bonding between the respective Lexan sheets, it has been observed that after a period of a few years, the methylene chloride tends to corrode the Lexan sheet leading to early failure thereof.
Additionally, the various chemicals within the paper stock flow itself have a detrimental effect on the known bonding solvents.
Aiso, from time to time, a mill will have a scheduled "boil out" in order to clean the headbox.
The aforementioned "boii out" includes filling the headbox including the slice chamber with a caustic cleaning liquid maintained at approximately 140 F for several hours. Typically, the caustic solution has a pH value of at least 13.
Consequently, it has been standard practice for mills to remove the Lexan sheets prior to performing the aforementioned "boil out" operation, In view of the fact that the removal of the Lexan sheets typically takes one hour and the replacement of the sheets after the "boil out" also involves an hours work, it is evident that the provision of CONVERFLO or * Txade-maxk trailing element sheets capable of withstanding a cleaning operation would be of great value.
Although graphite sheets are known to be able to withstand the hostile environment within a slice chamber during a "boil out" operation, such graphite sheets typically cost 10 times as much as the corresponding Lexan sheets.
The present invention overcomes the aforementioned problem by the provision of thermoplastic sheets which are fusion welded together and that are consequently able to withstand the caustic environment involved in a headbox cleaning operation. Also, the thermoplastic sheets are only marginally more expensive than their corresponding sheets fabricated from Lexan.
Therefore, it is the primary objective of the present invention to provide a trailing element device that overcomes the problems associated with prior art trailing elements and which makes a considerable contribution to the art of papermaking.
Another objective of the present invention is the provision of a trailing element device that does not require the use of methylene chloride, a known carcinogen, in the manufacture thereof.
Another objective of the present invention is the provision of a trailing element that is able to withstand the high temperatures and caustic environment typically present during a headbox cleaning operation.
Other objects and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed wo "/51856 pcrtis98ro5W
BACKGROUND OF THE iNVENTION
Field of the Invention The present invention relates to a trailing element device for controlling the magnitude and scale of turbulence of stock flowing through a slice chamber. More specifically, the present invention relates to a trailing element device for controlling the magnitude and scale of turbulence of stock flowing through a slice chamber of a headbox of a papermaking machine.
lnfgrmation Disciosure Statement In the papermaking art pressurized stock is ejected from a headbox onto a moving fourdrinier wire so that as water is drained from the stock through the fourdrinier wire, a web of paper is formed on the wire.
In order to control the magnitude and scale of turbulence of the stock fiowing "through the headbox and particularly the slice chamber thereof, trailing elements or CONVERFLO* sheets are anchored at the upstream end of the slice chamber. The arrangement is such that as the stock flows through the slice chamber, the trailing elements are freely suspended within the stock flow being anchored only at the upstream end thereof.
The aforementioned trailing elements are known In the art as CONVERFLO sheets. CONVERFLO is a common law trademark of Beloit Technoiogies, Inc.
* Trade-mark Typically, the trailing elements are fabricated from Lexan* sheets and the Lexan sheets are bonded together to form a composite sheet by means of chemical bonding agents. One type of bonding agent or solvent used for joining the Lexan sheets together is methylene chloride. However, methyiene chloride is known to be a carcinogen. Consequently, it is desirable to eliminate the use of the aforementioned bonding agents.
Moreover, aithough the use,of inethyfene chloride has been successful in providing an adequate bonding between the respective Lexan sheets, it has been observed that after a period of a few years, the methylene chloride tends to corrode the Lexan sheet leading to early failure thereof.
Additionally, the various chemicals within the paper stock flow itself have a detrimental effect on the known bonding solvents.
Aiso, from time to time, a mill will have a scheduled "boil out" in order to clean the headbox.
The aforementioned "boii out" includes filling the headbox including the slice chamber with a caustic cleaning liquid maintained at approximately 140 F for several hours. Typically, the caustic solution has a pH value of at least 13.
Consequently, it has been standard practice for mills to remove the Lexan sheets prior to performing the aforementioned "boil out" operation, In view of the fact that the removal of the Lexan sheets typically takes one hour and the replacement of the sheets after the "boil out" also involves an hours work, it is evident that the provision of CONVERFLO or * Txade-maxk trailing element sheets capable of withstanding a cleaning operation would be of great value.
Although graphite sheets are known to be able to withstand the hostile environment within a slice chamber during a "boil out" operation, such graphite sheets typically cost 10 times as much as the corresponding Lexan sheets.
The present invention overcomes the aforementioned problem by the provision of thermoplastic sheets which are fusion welded together and that are consequently able to withstand the caustic environment involved in a headbox cleaning operation. Also, the thermoplastic sheets are only marginally more expensive than their corresponding sheets fabricated from Lexan.
Therefore, it is the primary objective of the present invention to provide a trailing element device that overcomes the problems associated with prior art trailing elements and which makes a considerable contribution to the art of papermaking.
Another objective of the present invention is the provision of a trailing element device that does not require the use of methylene chloride, a known carcinogen, in the manufacture thereof.
Another objective of the present invention is the provision of a trailing element that is able to withstand the high temperatures and caustic environment typically present during a headbox cleaning operation.
Other objects and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed wo "/51856 pcrtis98ro5W
description contained hereinafter taking in conjunction with the annexed drawings.
The present invention relates to a trailing element device for controlling the magnitude and scale of turbulence of stock flowing through a slice chamber of a headbox of a papermaking machine.
The device Includes an upstream member. The upstream member incorporates a locking portion for locking the upstream member relative to an upstream end of the slice chamber.
The upstream member also includes a downstream portion disposed within the slice chamber and downstream relative to locking portion.
An intermediate portion is disposed between the locking portion and the downstream portion.
A downstream member Is disposed downstream relative to the downstream portion. The downstream member is fusion welded to the downstream portion.
More particularly, in specific embodiments of the present Invention, the upstream and downstream members are of thermoplastic material.
In a specific embodiment of the present invention, the thermoplastic material is either KYNAR 740* or KYNAR 741 *.
* Trade-mark In a preferred embodiment of the present invention, the intermediate portion has a z-direction thickness which is greater than a z-direction thickness of the downstream portion.
Many variations and modifications of the present invention will be readily apparent to those skilled in the art by consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings. However, such modifications and variations fall within the spirit and scope of the present invention as defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side elevational view showing a portion of a trailing element according to the present invention.
Fig. 2 is a side elevational view showing how the trailing element according to the present invention is fusion welded.
Similar reference characters refer to similar parts throughout the various views of the drawings.
DETAILED DESCRIPTION OF DRAWINGS
Figures 1 and 2 are side elevational views of a trailing element device for controlling the magnitude and the scale of turbulence of stocks flowing through a slice chamber 12 of a headbox of a papermaking machine. The device includes an upstream member generally designated 14.
The upstream member 14 includes a locking portion 16 for locking the upstream member 14 relative to an upstream end 18 of the slice chamber 12.
WO 98151856 PeT/US98105663 A downstream portion 20 is disposed within the slice chamber 12 and downstream relative to the locking portion 16.
An intermediate portion 22 is disposed betweeri the locking portion 16 and the downstream portion 20.
Also, a downstream member 24 is disposed downstream relative to the downstream portion 20. The downstream member 24 is fusion welded to the downstream portion 20.
More specificaUy, the upstream and the downstream members 14 &
24 are of thermoplastic material which may be either KYNAR 740*
or KYNAR 741 *.
As shown in Figs. 1 and 2, the intermediate portion 22 has a z-directionat thickness T-~which is greater than a z-direction thickness T1 of the downstream portion 20.
Fig. 2 shows how the downstream member 24 and the downstream portion 20 are fusion welded together. More specifically, clamps 26 and 28 are disposed adjacent to the downstream member 24 and the downstream portion 20 respectively.
The gripped downstream member 24 and the downstream portion 20 are pushed under pressure against a heated bar 30.
Once heated, the heated bar 30 is lowered as indicated by the arrow 32 and the pieces 20 & 24 are pushed together under high pressure. In order to provide heat for the welding process, the heated bar 30 is then * Trade--maxk raised as indicated by arrow 32 to just below the weld area until the weld process is completed.
The weld process is adjustable to optimize the results by varying the heat, the pressure and the weld time. The aforementioned parameters are then controlled using a computer in a closed loop feedback mode.
Moreover, the welding equipment is designed with an open throat which allows unlimited lengths of the parts to be processed.
The present invention provides a unique low cost trailing element device which is capable of withstanding high temperatures and the caustic environment associated with a headbox cleaning operation.
The present invention relates to a trailing element device for controlling the magnitude and scale of turbulence of stock flowing through a slice chamber of a headbox of a papermaking machine.
The device Includes an upstream member. The upstream member incorporates a locking portion for locking the upstream member relative to an upstream end of the slice chamber.
The upstream member also includes a downstream portion disposed within the slice chamber and downstream relative to locking portion.
An intermediate portion is disposed between the locking portion and the downstream portion.
A downstream member Is disposed downstream relative to the downstream portion. The downstream member is fusion welded to the downstream portion.
More particularly, in specific embodiments of the present Invention, the upstream and downstream members are of thermoplastic material.
In a specific embodiment of the present invention, the thermoplastic material is either KYNAR 740* or KYNAR 741 *.
* Trade-mark In a preferred embodiment of the present invention, the intermediate portion has a z-direction thickness which is greater than a z-direction thickness of the downstream portion.
Many variations and modifications of the present invention will be readily apparent to those skilled in the art by consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings. However, such modifications and variations fall within the spirit and scope of the present invention as defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side elevational view showing a portion of a trailing element according to the present invention.
Fig. 2 is a side elevational view showing how the trailing element according to the present invention is fusion welded.
Similar reference characters refer to similar parts throughout the various views of the drawings.
DETAILED DESCRIPTION OF DRAWINGS
Figures 1 and 2 are side elevational views of a trailing element device for controlling the magnitude and the scale of turbulence of stocks flowing through a slice chamber 12 of a headbox of a papermaking machine. The device includes an upstream member generally designated 14.
The upstream member 14 includes a locking portion 16 for locking the upstream member 14 relative to an upstream end 18 of the slice chamber 12.
WO 98151856 PeT/US98105663 A downstream portion 20 is disposed within the slice chamber 12 and downstream relative to the locking portion 16.
An intermediate portion 22 is disposed betweeri the locking portion 16 and the downstream portion 20.
Also, a downstream member 24 is disposed downstream relative to the downstream portion 20. The downstream member 24 is fusion welded to the downstream portion 20.
More specificaUy, the upstream and the downstream members 14 &
24 are of thermoplastic material which may be either KYNAR 740*
or KYNAR 741 *.
As shown in Figs. 1 and 2, the intermediate portion 22 has a z-directionat thickness T-~which is greater than a z-direction thickness T1 of the downstream portion 20.
Fig. 2 shows how the downstream member 24 and the downstream portion 20 are fusion welded together. More specifically, clamps 26 and 28 are disposed adjacent to the downstream member 24 and the downstream portion 20 respectively.
The gripped downstream member 24 and the downstream portion 20 are pushed under pressure against a heated bar 30.
Once heated, the heated bar 30 is lowered as indicated by the arrow 32 and the pieces 20 & 24 are pushed together under high pressure. In order to provide heat for the welding process, the heated bar 30 is then * Trade--maxk raised as indicated by arrow 32 to just below the weld area until the weld process is completed.
The weld process is adjustable to optimize the results by varying the heat, the pressure and the weld time. The aforementioned parameters are then controlled using a computer in a closed loop feedback mode.
Moreover, the welding equipment is designed with an open throat which allows unlimited lengths of the parts to be processed.
The present invention provides a unique low cost trailing element device which is capable of withstanding high temperatures and the caustic environment associated with a headbox cleaning operation.
Claims (6)
1. A method of making a thermoplastic trailing element device for controlling the magnitude and scale of turbulence of stock flowing through a slice chamber of a headbox of a papermaking machine, the method comprising:
joining a downstream portion of an upstream member;
the upstream member having a locking portion for locking said upstream member relative to an upstream end of the slice chamber, and having the downstream portion downstream relative to said locking portion; and an intermediate portion disposed between said locking portion and said downstream portion, to a downstream member disposed downstream relative to the downstream portion, by fusion welding; wherein the step of joining by fusion welding further comprises the steps of:
heating the downstream portion;
heating the downstream member; and pressing the downstream portion against the downstream member to form a fusion weld.
joining a downstream portion of an upstream member;
the upstream member having a locking portion for locking said upstream member relative to an upstream end of the slice chamber, and having the downstream portion downstream relative to said locking portion; and an intermediate portion disposed between said locking portion and said downstream portion, to a downstream member disposed downstream relative to the downstream portion, by fusion welding; wherein the step of joining by fusion welding further comprises the steps of:
heating the downstream portion;
heating the downstream member; and pressing the downstream portion against the downstream member to form a fusion weld.
2. A method of making a thermoplastic trailing element device for controlling the magnitude and scale of turbulence of stock flowing through a slice chamber of a headbox of a papermaking machine, the method comprising:
joining a downstream portion of an upstream member; the upstream member having a locking portion for locking said upstream member relative to an upstream end of the slice chamber, and having the downstream portion downstream relative to said locking portion; and an intermediate portion disposed between said locking portion and said downstream portion, to a downstream member disposed downstream relative to downstream portion, by fusion welding; wherein the step of joining by fusion welding further comprises the steps of:
pressing the downstream portion against a heated bar between the downstream portion and the downstream member to heat the downstream portion;
pressing the downstream member against the heated bar to heat the downstream member; and moving the heated bar from between the downstream portion and the downstream member and pressing the downstream portion against downstream member to form a fusion weld.
joining a downstream portion of an upstream member; the upstream member having a locking portion for locking said upstream member relative to an upstream end of the slice chamber, and having the downstream portion downstream relative to said locking portion; and an intermediate portion disposed between said locking portion and said downstream portion, to a downstream member disposed downstream relative to downstream portion, by fusion welding; wherein the step of joining by fusion welding further comprises the steps of:
pressing the downstream portion against a heated bar between the downstream portion and the downstream member to heat the downstream portion;
pressing the downstream member against the heated bar to heat the downstream member; and moving the heated bar from between the downstream portion and the downstream member and pressing the downstream portion against downstream member to form a fusion weld.
3. The method of claim 1 or claim 2, further comprising the step of:
providing heat for the fusion welding by positioning the heated bar to heat the fusion welded.
providing heat for the fusion welding by positioning the heated bar to heat the fusion welded.
4. The method of claim 3, wherein the weld process is adjusted to optimize the results by varying heating from the bar, pressure used and weld time using a computer in a closed loop feedback mode.
5. The method of claim 1 or claim 2, wherein the thermoplastic trailing element is composed of Polyvinylidene Fluoride so that the fusion weld is formed of Polyvinylidene Fluoride joined to Polyvinylidene Fluoride.
6. The method of claim 1 or claim 2, wherein the thermoplastic trailing element intermediate portion has a z-direction thickness which is greater than a z-direction thickness of said downstream portion.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US85460597A | 1997-05-12 | 1997-05-12 | |
| US08/854,605 | 1997-05-12 | ||
| PCT/US1998/005663 WO1998051856A1 (en) | 1997-05-12 | 1998-03-20 | A trailing element device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2325990A1 CA2325990A1 (en) | 1998-11-19 |
| CA2325990C true CA2325990C (en) | 2007-09-18 |
Family
ID=25319141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002325990A Expired - Fee Related CA2325990C (en) | 1997-05-12 | 1998-03-20 | A trailing element device |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2325990C (en) |
| WO (1) | WO1998051856A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19946756A1 (en) * | 1999-09-29 | 2001-04-12 | Voith Paper Patent Gmbh | Stock inlet for a papermaking or cardboard prodn machine has a blade inserted between the rows of turbulence tubes with a lateral zone of a reduced cross section to reduce force peaks on starting/stopping the stock inlet |
| DE10051802A1 (en) | 2000-10-18 | 2002-04-25 | Voith Paper Patent Gmbh | Slat of a headbox of a paper, cardboard or tissue machine |
| US6521095B1 (en) | 2002-02-05 | 2003-02-18 | Metso Paper, Inc. | Composite vane hinge in a headbox |
| EP1798337A4 (en) * | 2004-10-05 | 2009-02-18 | Toray Industries | Flow sheet for paper machine and method of manufacturing the same |
| FI20055093A (en) * | 2005-02-25 | 2006-08-26 | Metso Paper Inc | A turbulence element and a method for making a turbulence element |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3888729A (en) * | 1972-11-06 | 1975-06-10 | Joseph D Parker | Papermaking machine headbox slice chamber containing pivotable thin rigid plates with flexible elements attached thereto |
| US3853697A (en) * | 1973-03-08 | 1974-12-10 | Beloit Corp | Papermaking machine headbox with an upwardly inclined slice chamber portion, an arcuate portion, and a downwardly inclined portion and containing flexible trailing members |
| CA1230251A (en) * | 1983-11-25 | 1987-12-15 | Jose J. A. Rodal | Converflo trailing element |
| DE3607306A1 (en) * | 1986-03-06 | 1987-09-10 | Voith Gmbh J M | FABRIC OUTLET FOR THE PRODUCTION OF FIBERGLASS FILMS |
| SE501798C2 (en) * | 1993-09-13 | 1995-05-15 | Valmet Karlstad Ab | Multilayer headbox |
| EP0681057B1 (en) * | 1994-04-29 | 2002-08-28 | Voith Paper Patent GmbH | Multi-layer headbox |
-
1998
- 1998-03-20 CA CA002325990A patent/CA2325990C/en not_active Expired - Fee Related
- 1998-03-20 WO PCT/US1998/005663 patent/WO1998051856A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| CA2325990A1 (en) | 1998-11-19 |
| WO1998051856A1 (en) | 1998-11-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |