CA2065166C - Heated backing roll apparatus - Google Patents
Heated backing roll apparatusInfo
- Publication number
- CA2065166C CA2065166C CA 2065166 CA2065166A CA2065166C CA 2065166 C CA2065166 C CA 2065166C CA 2065166 CA2065166 CA 2065166 CA 2065166 A CA2065166 A CA 2065166A CA 2065166 C CA2065166 C CA 2065166C
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- CA
- Canada
- Prior art keywords
- coating
- web
- roll apparatus
- backing roll
- pressing section
- 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
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- Application Of Or Painting With Fluid Materials (AREA)
- Paper (AREA)
- Coating Apparatus (AREA)
Abstract
A heated backing roll is disclosed for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web. The roll apparatus includes a rotatable, cylindrical body which defines a circumferential outer surface. A coating is applied to the outer surface of the body such that the coating is disposed in pressing contact with the web during the passage of the web through the pressing section. The coating has properties which inhibit sticking of the web to the coating subsequent to the passage of the web through the pressing section. The coating includes a mixture of chromium and TEFLON.
Description
~ FB344331548US
PATENT APPLICATION
TITLE: A HEAT~U BACRING ROLL APPARATUS
BACRGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web. More particularly, the present invention relates to a heated extended nip press in which the web is disposed in physical contact with a portion of the surface of the backing roll.
lN~Ok~ATION DISCLOSURE STAT~M~NT
Approximately 80 extended nip presses are currently in operation worldwide.
An extended nip press essentially includes a backing roll which cooperates with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web. A looped bearing blanket also extends through the pressing section, the blanket slidably engaging a concave surface defined by the shoe such that the web extends with the blanket through the pressing section.
The extended nip press arrangement has considerable advantages over the more conventional roll couple press which includes at least two counter-rotating pressing rolls which define therebetween a pressing nip.
The primary advantage of the extended nip press is the increased residence time of the web during passage through the pressing section.
More recently, research has been carried out in an attempt to further increase the water removing capabilities of an extended nip press. More particularly, by heating the backing roll to a high temperature, water vapor generated within the extended pressing section further assists in pumping water remaining in the web in the liquid phase away from the web. Typically, such backing roll is heated by means of an induction heater, or the like.
However, a problem has been experienced with the aforementioned so-called heated extended nip press, or high temperature press (HTP), in that there exists a tendency for the pressed web to stick to the outer surface of the backing roll downstream relative to the extended pressing section.
Additionally, individual fibers within the pressed web tend to adhere to the heated surface of the backing roll downstream relative to the extended pressing section, thereby resulting in the phenomenon known as "picking of fibers".
2065 ~ 66 Both of the aforementioned problems are detrimental to the efficient production of a pressed web of paper or liner board.
In more severe circumstances, there exists a tendency for the web to delaminate on exiting from the pressing section with one layer of the pressed web transferring from the pressing section to a downstream drying section while a further layer of the pressed web adheres to and r~m~; n.C in contact with the backing roll.
Various attempts have been made in order to overcome the aforementioned problem.
One method of overcoming the aforementioned problems includes spraying the upstream surface of the heated backing roll with an atomized layer of release agent. However, such release agents are not only relatively costly but sometimes deleteriously affect the resultant pressed web.
Additionally, the application of a uniform layer of release agent to a heated backing roll is relatively complex.
Experiments were carried out using a steel backing roll with a chrome-plated surface. However, such chromium surface was not altogether successful in providing a uniform release of the pressed web.
The present invention provides a coating which includes a matrix of chromium and TEFLON which has been very successful in readily releasing the pressed web from the surface of the heated backing roll. TEFLON is a registered Federal trademark owned by E. I. Du Pont De Nemours &
Company.
Therefore, it is a primary objective of the present invention to provide a heated backing roll and a method of making such backing roll which makes a considerable contribution to the art of pressing a web of paper or liner boarc.
Another object of the present invention is the provis-ion of a heated backing roll apparatus which includes a coating of chromium and TEFLON.
Another object of the present invention is the provision of a backing roll apparatus which includes an outer surface having a matrix coating of chromium and TEFLON, the coating being abraded in order to expose the chromium nodules within the matrix.
Other objects and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings.
-SUMMARY OF l~ INVENTION
The present invention relates to a heated backing roll apparatus and a method for making the same. The backing roll apparatus cooperates with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web of paper or liner board. The roll apparatus includes a rotatable, cylindrical body which defines a circumferential outer surface. A coating is applied to the outer surface of the body such that the coating is disposed in pressing contact with the web during the passage of the web through the pressing section. The coating has properties which inhibit sticking of the web to the coating subsequent to the passage of the web through the pressi-ng section. The coating includes a mixture of chromium and TEFLON.
More specifically, in one embodiment of the present invention, the cylindrical body is of steel, and in another embodiment of the present invention, the cylindrical body is of cast iron.
The coating is applied as a matrix to the outer surface of the body, the arrangement being such that the coating inhibits picking of fibers disposed within the web.
The coating includes chromium within the range 15 to 55 percent by weight and TEFLON within the range 45 to 85 percent by weight.
In one embodiment of the present invention, the coating includes chromium within the range 55 to 45 percent by weight and TEFLON within the range 45 to 55 percent by weight.
In another embodiment of the present invention, the coating includes chromium within the range 15 to 25 percent by weight and TEFLON within the range 75 to 85 percent by weight.
In a preferred embodiment of the present invention, the coating includes chromium within the range 25 to 35 percent by weight and TEFLON within the range 65 to 75 percent by weight-.
In each of the aforementioned embodiments of the present invention, the cylindrical body and the coating are heated to a temperature within the range 180 to 650~
Fahrenheit, and the backing roll rotates at a peripheral speed of up to 6,000 feet per minute.
In an alternative embodiment of the present invention, the coating includes a mixture of chromium and a ceramic material.
In a more specific embodiment of the present invention, the coating includes a mixture of chromium and zirconia.
In yet another embodiment of the present invention, the heated backing roll cooperates with a press roll, and the backing roll apparatus includes a coating having a mixture of chromium and TEFLON.
The present invention includes a method of making a heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web. The method includes the step of applying a coating to an outer surface of a rotatable cylindrical body. The arrangement is such that in use of the backing roll apparatus, the coating is disposed in pressing contact with the web during passage of the web through the pressing section. The coating has properties which inhibit sticking of the web to the coating subsequent to the passage of the web through the pressing section. The coating includes a mixture of chromium and TEFLON.
Additionally, the method includes the step of abrading the coating prior to use of the backing roll apparatus so that a percentage of chromium nodules within the mixture of chromium and TEFLON are exposed with the balance of the mixture between the chromium nodules being TEFLON.
The abrading step also further includes abrading the coating by a doctor blade pressed into doctoring relationship relative to the coating.
Many modifications and variations of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description 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.
Included in such modifications and variations would be the provision of an amorphous coating on the backing roll, such amorphous coating including an iron-based alloy. More specifically, the iron-based alloy would include iron, chromium and boron.
~ he amorphous coating is plasma sprayed onto the cylindrical body. The amorphous nature of the alloy is produced by a special hardening phenomenon. Such hardening phenomenon includes a transformation from a two-phase crystalline alloy to a complex, stable amorphous hard-surface alloy which is corrosion and wear resistant.
Tests have indicated that such amorphous coating is non-sticking.
In another variation of the present invention, the coating is a ceramic/TEFLON matrix in which the TEFLON fills the voids, that is the porosity in the ceramic material.
More particularly, the ceramic is an aluminum oxide and titanium oxide, and the balance is TEFLON. In one particular example, the exposed area of TEFLON is 67 percent of the total surface area, whereas in another example, 37 percent of surface is TEFLON.
The essential feature of such coating is to inhibit sticking of the pressed web to the surface of the backing roll.
BRIEE DESCRIPTION OF THE DRAWINGS
Figure 1 is a side-elevational view of a heated backing roll apparatus according to the present invention showing an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of the web;
Figure 2 is a side-elevational view of an alternative embodiment of the present invention in which a heated backing roll apparatus cooperates with a press roll for defining therebetween a pressing section for the passage therethrough of a web; and Figure 3 is an enlarged sectional view through the heated backing roll apparatus shown in Figure 1 showing a method of abrading the coating prior to use thereof by means of a doctor blade pressed into doctoring relationship relative to the coating.
. FB344331548US
Similar reference characters refer to similar parts throughout the various embodiments of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Figure 1 is a side-elevational view of a heated backing roll apparatus, generally designated 10, for cooperation with an elongate shoe 12 for defining therebetween an extended pressing section 14 for the passage therethrough of a web 16. The roll apparatus 10 includes a rotatable, cylindrical body 18 which defines a circumferential outer surface 20.
A coating 22 is applied to the outer surface 20 of the body --18 such that the coating 22 is disposed in pressing contact with the web 16 during the passage of the web 16 through the pressing section 14. The coating 22 has properties which inhibit sticking of the web 16 to the coating 22 subsequent to the passage of the web 16 through the pressing sectior. 14. The coating 22 includes a mixture of chromium and TEFLON.
In one embodiment of the present invention, the cylindrical body 18 is of steel, and in another embodiment of the present invention, the cylindrical body is of cast iron.
The coating 22 is applied as a matrix to the outer surface 20 of the body 18. The arrangement is such that the coating 22 inhibits picking of fibers disposed within the web 16.
In one embodiment of the present invention, the coating 22 includes chromium within the range 15 to 55 percent by weight and TEFLON within the range 45 to 85 percent by weight.
In another embodiment of the present invention, the coating 22 includes chromium within the range 55 to 45 percent by weight and TEFLON within the range 45 to 55 percent by weight.
In yet another embodiment of the present invention, the coating 22 includes chromium within the range 15 to 25 percent by weight and TEFLON within the range 75 to 85 percent by weight.
In a preferred embodiment of the present invention, the coating 22 includes chromium within the range 25 to 35 percent by weight and TEFLON within the range 65 to 75 percent by weight.
A coating with 30 percent chromium and 70 percent TEFLON was very successful in inhibiting delamination. The backing roll was heated to 600 Fahrenheit with the formed web having an in-going solids content of 34 percent. The pressed web had an out-going solids of between 50 to 70 percent, and no delamination of the liner board occurred.
. FB344331548US
The backing roll apparatus 10, including the cylindrical body 18 and coating 22, are heated to a temperature within the range 180 to 650 Fahrenheit, and the backing roll apparatus~10 rotates at a peripheral speed of up to 6,000 feet per minute.
In an alternative embodiment of the present invention, the coating 22 includes a mixture of chromium and ceramics material.
More specifically, in the alternative embodiment of the present nvention, the coating 22 includes a mixture of chromium and zirconia.
Additionally, as shown in Figure 1, an induction heater 26 heats the coating 22 and the cylindrical body 18.
Also, a looped bearing blanket 28 extends through the pressing section 14 and slidably cooperates with a concave surface 30 defined by the elongate shoe 12.
A press felt 32 is disposed between the blanket 28 and the web 16 for absorbing water -removed from the web 16 during passage of the web 16 through the extended pressing section 14.
In another embodiment of the present invention as shown in Figure 2, the shoe 12 is replaced by a conventional press `_ roll 12A for defining therebetween a pressing section 14A
for the passage therethrough of a web 16A. The coating 22A
includes a mixture of chromium and TEFLON.
Figure 3 is an enlarged sectional view showing how the heated backing roll apparatus 10 is manufactured. The roll apparatus 10 cooperates with an elongate shoe 12 for defining therebetween an extended pressing section 14 for the passage therethrough of a web 16. The method comprises the step of applying a coating, generally designated 22, to an outer surface 20 of a rotatable cylindrical body 18 such that in use of the backing roll apparatus 10, the coating 22 is disposed in pressing contact with the web 16 during passage of the web 16 through the pressing section 14. The coating 22 has properties which inhibit sticking of the web 16 to the coating 22 subsequent to the passage of the web 16 through the pressing section 14. The coating 22 includes a mixture of chromium and TEFLON.
As shown in Figure 3, the coating 22 is abraded prior to use of the backing roll apparatus 10 so that a percentage of chromium nodules 34, which are shown in an exaggerated size for clarity, are exposed within the mixture of chromium and TEFLON. Such nodules 34 are exposed by such abrasion with the balance of the mixture between the chromium nodules being TEFLON 36.
-More specifically, the abrading step includes abrading the coating 22 by a doctor blade 24 pressed into doctoring relationship relative to the coating 22.
The present invention provides a coating for a backing roll of a high temperature press which inhibits the problem of sticking of the web to the backing roll subsequent to pressing.
PATENT APPLICATION
TITLE: A HEAT~U BACRING ROLL APPARATUS
BACRGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web. More particularly, the present invention relates to a heated extended nip press in which the web is disposed in physical contact with a portion of the surface of the backing roll.
lN~Ok~ATION DISCLOSURE STAT~M~NT
Approximately 80 extended nip presses are currently in operation worldwide.
An extended nip press essentially includes a backing roll which cooperates with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web. A looped bearing blanket also extends through the pressing section, the blanket slidably engaging a concave surface defined by the shoe such that the web extends with the blanket through the pressing section.
The extended nip press arrangement has considerable advantages over the more conventional roll couple press which includes at least two counter-rotating pressing rolls which define therebetween a pressing nip.
The primary advantage of the extended nip press is the increased residence time of the web during passage through the pressing section.
More recently, research has been carried out in an attempt to further increase the water removing capabilities of an extended nip press. More particularly, by heating the backing roll to a high temperature, water vapor generated within the extended pressing section further assists in pumping water remaining in the web in the liquid phase away from the web. Typically, such backing roll is heated by means of an induction heater, or the like.
However, a problem has been experienced with the aforementioned so-called heated extended nip press, or high temperature press (HTP), in that there exists a tendency for the pressed web to stick to the outer surface of the backing roll downstream relative to the extended pressing section.
Additionally, individual fibers within the pressed web tend to adhere to the heated surface of the backing roll downstream relative to the extended pressing section, thereby resulting in the phenomenon known as "picking of fibers".
2065 ~ 66 Both of the aforementioned problems are detrimental to the efficient production of a pressed web of paper or liner board.
In more severe circumstances, there exists a tendency for the web to delaminate on exiting from the pressing section with one layer of the pressed web transferring from the pressing section to a downstream drying section while a further layer of the pressed web adheres to and r~m~; n.C in contact with the backing roll.
Various attempts have been made in order to overcome the aforementioned problem.
One method of overcoming the aforementioned problems includes spraying the upstream surface of the heated backing roll with an atomized layer of release agent. However, such release agents are not only relatively costly but sometimes deleteriously affect the resultant pressed web.
Additionally, the application of a uniform layer of release agent to a heated backing roll is relatively complex.
Experiments were carried out using a steel backing roll with a chrome-plated surface. However, such chromium surface was not altogether successful in providing a uniform release of the pressed web.
The present invention provides a coating which includes a matrix of chromium and TEFLON which has been very successful in readily releasing the pressed web from the surface of the heated backing roll. TEFLON is a registered Federal trademark owned by E. I. Du Pont De Nemours &
Company.
Therefore, it is a primary objective of the present invention to provide a heated backing roll and a method of making such backing roll which makes a considerable contribution to the art of pressing a web of paper or liner boarc.
Another object of the present invention is the provis-ion of a heated backing roll apparatus which includes a coating of chromium and TEFLON.
Another object of the present invention is the provision of a backing roll apparatus which includes an outer surface having a matrix coating of chromium and TEFLON, the coating being abraded in order to expose the chromium nodules within the matrix.
Other objects and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings.
-SUMMARY OF l~ INVENTION
The present invention relates to a heated backing roll apparatus and a method for making the same. The backing roll apparatus cooperates with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web of paper or liner board. The roll apparatus includes a rotatable, cylindrical body which defines a circumferential outer surface. A coating is applied to the outer surface of the body such that the coating is disposed in pressing contact with the web during the passage of the web through the pressing section. The coating has properties which inhibit sticking of the web to the coating subsequent to the passage of the web through the pressi-ng section. The coating includes a mixture of chromium and TEFLON.
More specifically, in one embodiment of the present invention, the cylindrical body is of steel, and in another embodiment of the present invention, the cylindrical body is of cast iron.
The coating is applied as a matrix to the outer surface of the body, the arrangement being such that the coating inhibits picking of fibers disposed within the web.
The coating includes chromium within the range 15 to 55 percent by weight and TEFLON within the range 45 to 85 percent by weight.
In one embodiment of the present invention, the coating includes chromium within the range 55 to 45 percent by weight and TEFLON within the range 45 to 55 percent by weight.
In another embodiment of the present invention, the coating includes chromium within the range 15 to 25 percent by weight and TEFLON within the range 75 to 85 percent by weight.
In a preferred embodiment of the present invention, the coating includes chromium within the range 25 to 35 percent by weight and TEFLON within the range 65 to 75 percent by weight-.
In each of the aforementioned embodiments of the present invention, the cylindrical body and the coating are heated to a temperature within the range 180 to 650~
Fahrenheit, and the backing roll rotates at a peripheral speed of up to 6,000 feet per minute.
In an alternative embodiment of the present invention, the coating includes a mixture of chromium and a ceramic material.
In a more specific embodiment of the present invention, the coating includes a mixture of chromium and zirconia.
In yet another embodiment of the present invention, the heated backing roll cooperates with a press roll, and the backing roll apparatus includes a coating having a mixture of chromium and TEFLON.
The present invention includes a method of making a heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web. The method includes the step of applying a coating to an outer surface of a rotatable cylindrical body. The arrangement is such that in use of the backing roll apparatus, the coating is disposed in pressing contact with the web during passage of the web through the pressing section. The coating has properties which inhibit sticking of the web to the coating subsequent to the passage of the web through the pressing section. The coating includes a mixture of chromium and TEFLON.
Additionally, the method includes the step of abrading the coating prior to use of the backing roll apparatus so that a percentage of chromium nodules within the mixture of chromium and TEFLON are exposed with the balance of the mixture between the chromium nodules being TEFLON.
The abrading step also further includes abrading the coating by a doctor blade pressed into doctoring relationship relative to the coating.
Many modifications and variations of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description 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.
Included in such modifications and variations would be the provision of an amorphous coating on the backing roll, such amorphous coating including an iron-based alloy. More specifically, the iron-based alloy would include iron, chromium and boron.
~ he amorphous coating is plasma sprayed onto the cylindrical body. The amorphous nature of the alloy is produced by a special hardening phenomenon. Such hardening phenomenon includes a transformation from a two-phase crystalline alloy to a complex, stable amorphous hard-surface alloy which is corrosion and wear resistant.
Tests have indicated that such amorphous coating is non-sticking.
In another variation of the present invention, the coating is a ceramic/TEFLON matrix in which the TEFLON fills the voids, that is the porosity in the ceramic material.
More particularly, the ceramic is an aluminum oxide and titanium oxide, and the balance is TEFLON. In one particular example, the exposed area of TEFLON is 67 percent of the total surface area, whereas in another example, 37 percent of surface is TEFLON.
The essential feature of such coating is to inhibit sticking of the pressed web to the surface of the backing roll.
BRIEE DESCRIPTION OF THE DRAWINGS
Figure 1 is a side-elevational view of a heated backing roll apparatus according to the present invention showing an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of the web;
Figure 2 is a side-elevational view of an alternative embodiment of the present invention in which a heated backing roll apparatus cooperates with a press roll for defining therebetween a pressing section for the passage therethrough of a web; and Figure 3 is an enlarged sectional view through the heated backing roll apparatus shown in Figure 1 showing a method of abrading the coating prior to use thereof by means of a doctor blade pressed into doctoring relationship relative to the coating.
. FB344331548US
Similar reference characters refer to similar parts throughout the various embodiments of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Figure 1 is a side-elevational view of a heated backing roll apparatus, generally designated 10, for cooperation with an elongate shoe 12 for defining therebetween an extended pressing section 14 for the passage therethrough of a web 16. The roll apparatus 10 includes a rotatable, cylindrical body 18 which defines a circumferential outer surface 20.
A coating 22 is applied to the outer surface 20 of the body --18 such that the coating 22 is disposed in pressing contact with the web 16 during the passage of the web 16 through the pressing section 14. The coating 22 has properties which inhibit sticking of the web 16 to the coating 22 subsequent to the passage of the web 16 through the pressing sectior. 14. The coating 22 includes a mixture of chromium and TEFLON.
In one embodiment of the present invention, the cylindrical body 18 is of steel, and in another embodiment of the present invention, the cylindrical body is of cast iron.
The coating 22 is applied as a matrix to the outer surface 20 of the body 18. The arrangement is such that the coating 22 inhibits picking of fibers disposed within the web 16.
In one embodiment of the present invention, the coating 22 includes chromium within the range 15 to 55 percent by weight and TEFLON within the range 45 to 85 percent by weight.
In another embodiment of the present invention, the coating 22 includes chromium within the range 55 to 45 percent by weight and TEFLON within the range 45 to 55 percent by weight.
In yet another embodiment of the present invention, the coating 22 includes chromium within the range 15 to 25 percent by weight and TEFLON within the range 75 to 85 percent by weight.
In a preferred embodiment of the present invention, the coating 22 includes chromium within the range 25 to 35 percent by weight and TEFLON within the range 65 to 75 percent by weight.
A coating with 30 percent chromium and 70 percent TEFLON was very successful in inhibiting delamination. The backing roll was heated to 600 Fahrenheit with the formed web having an in-going solids content of 34 percent. The pressed web had an out-going solids of between 50 to 70 percent, and no delamination of the liner board occurred.
. FB344331548US
The backing roll apparatus 10, including the cylindrical body 18 and coating 22, are heated to a temperature within the range 180 to 650 Fahrenheit, and the backing roll apparatus~10 rotates at a peripheral speed of up to 6,000 feet per minute.
In an alternative embodiment of the present invention, the coating 22 includes a mixture of chromium and ceramics material.
More specifically, in the alternative embodiment of the present nvention, the coating 22 includes a mixture of chromium and zirconia.
Additionally, as shown in Figure 1, an induction heater 26 heats the coating 22 and the cylindrical body 18.
Also, a looped bearing blanket 28 extends through the pressing section 14 and slidably cooperates with a concave surface 30 defined by the elongate shoe 12.
A press felt 32 is disposed between the blanket 28 and the web 16 for absorbing water -removed from the web 16 during passage of the web 16 through the extended pressing section 14.
In another embodiment of the present invention as shown in Figure 2, the shoe 12 is replaced by a conventional press `_ roll 12A for defining therebetween a pressing section 14A
for the passage therethrough of a web 16A. The coating 22A
includes a mixture of chromium and TEFLON.
Figure 3 is an enlarged sectional view showing how the heated backing roll apparatus 10 is manufactured. The roll apparatus 10 cooperates with an elongate shoe 12 for defining therebetween an extended pressing section 14 for the passage therethrough of a web 16. The method comprises the step of applying a coating, generally designated 22, to an outer surface 20 of a rotatable cylindrical body 18 such that in use of the backing roll apparatus 10, the coating 22 is disposed in pressing contact with the web 16 during passage of the web 16 through the pressing section 14. The coating 22 has properties which inhibit sticking of the web 16 to the coating 22 subsequent to the passage of the web 16 through the pressing section 14. The coating 22 includes a mixture of chromium and TEFLON.
As shown in Figure 3, the coating 22 is abraded prior to use of the backing roll apparatus 10 so that a percentage of chromium nodules 34, which are shown in an exaggerated size for clarity, are exposed within the mixture of chromium and TEFLON. Such nodules 34 are exposed by such abrasion with the balance of the mixture between the chromium nodules being TEFLON 36.
-More specifically, the abrading step includes abrading the coating 22 by a doctor blade 24 pressed into doctoring relationship relative to the coating 22.
The present invention provides a coating for a backing roll of a high temperature press which inhibits the problem of sticking of the web to the backing roll subsequent to pressing.
Claims (8)
1. In a pressing action, a backing roll apparatus which cooperates with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web, said roll apparatus comprising:
a rotable, cylindrical body defining a circumferential outer service;
means for heating said outer surface;
a coating applied to said outer surface of said body, the arrangement being such that in use, when the backing roll is heated, said coating is disposed in pressing contact with the web during said passage of the web through said extended pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said extended pressing section; and said coating including:
a mixture of chromium and Polytetrafluorcarbon.
a rotable, cylindrical body defining a circumferential outer service;
means for heating said outer surface;
a coating applied to said outer surface of said body, the arrangement being such that in use, when the backing roll is heated, said coating is disposed in pressing contact with the web during said passage of the web through said extended pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said extended pressing section; and said coating including:
a mixture of chromium and Polytetrafluorcarbon.
2. A heated backing roll apparatus as set forth in claim 1 wherein said cylindrical body is of steel.
3. A heated backing roll apparatus as set forth in claim 1 wherein said cylindrical body is of cast iron.
4. A heated backing roll apparatus as set forth in claim 1 wherein said coating includes:
chromium within the range 15 to 55 percent by weight, a and Polytetrafluorocarbon within the range 45 to 85 percent by weight.
chromium within the range 15 to 55 percent by weight, a and Polytetrafluorocarbon within the range 45 to 85 percent by weight.
5. A heated backing roll apparatus as set forth in claim 1 wherein said coating includes:
chromium within the range 55 to 45 percent by weight, and Polytetrafluorocarbon within the range 45 to 55 percent by weight.
chromium within the range 55 to 45 percent by weight, and Polytetrafluorocarbon within the range 45 to 55 percent by weight.
6. A heated backing roll apparatus as set forth in claim 1 wherein said coating includes:
chromium within the range 15 to 25 percent by weight;
and Polytetrafluorocarbon within the range 75 to 85 percent by weight.
chromium within the range 15 to 25 percent by weight;
and Polytetrafluorocarbon within the range 75 to 85 percent by weight.
7. A heated backing roll apparatus as set forth in claim 1 wherein said coating includes:
chromium within the range 25 to 35 percent by weight;
and Polytetrafluorocarbon within the range 65 to 75 percent by weight.
chromium within the range 25 to 35 percent by weight;
and Polytetrafluorocarbon within the range 65 to 75 percent by weight.
8. A heated backing roll apparatus as set forth in claim 1 wherein said means for heating heats said cylindrical body and coating to a temperature within the range 180° to 650° Fahrenheit.9. A heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web, said roll apparatus comprising:
a rotable, cylindrical body defining a circumferential outer surface;
a coating applied to said outer surface of said body such that said coating is disposed in pressing contact with the web during said passage of the web through said pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said pressing section; and said coating including:
a mixture of chromium and a ceramics material.
10. A heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web, said roll apparatus comprisingl:
a rotable, cylindrical body defining a circumferential outer surface;
a coating applied to said outer surface of said body such that said coating is disposed in pressing contact with the web during said passage of the web through said pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said pressing section; and said coating including:
a mixture of chromium and zirconia.
11. A heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of the web, said roll apparatus comprising:
a rotable, cylindrical body defining a circumferential outer surface;
a coating applied to said outer surface of said body such that said coating is disposed in pressing contact with the web during said passage of the web through said pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said pressing section; and said coating including:
an amorphous alloy including a mixture of iron, chrome and boron.
12. A heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web, said roll apparatus comprising:
a rotable, cylindrical body defining a circumferential outer surface;
a coating applied to said outer surface of said body such that said coating is disposed in pressing contact with the web during said passage of the web through said pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said pressing section; and said coating including:
a matrix of ceramic and Polytetrafluoroethylene.
13. A method of making a heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web, said method comprising the step of:
applying a coating to an outer surface of a rotable, cylindrical body such that in use of the backing roll apparatus, the coating is disposed in pressing contact with the web during passage of the web through the pressing section, the coating having properties which inhibit sticking of the web to the coating subsequent to the passage of the web through the pressing section, the coating including a mixture of chromium and Polytetrafluoroethylene.
14. A method as set forth in claim 13, further including the step of:
abrading the coating prior to use of the backing roll apparatus so that a high percentage of chromium nodules within the mixture of chromium and Polytetrafluoroethylene are exposed with the balance of the mixture between the chromium nodules being Polyfluoroethylene.
15. A method as set forth in claim 14, wherein the abrading step includes:
abrading the coating by a doctor blade pressed into doctoring relationship relative to the coating.
a rotable, cylindrical body defining a circumferential outer surface;
a coating applied to said outer surface of said body such that said coating is disposed in pressing contact with the web during said passage of the web through said pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said pressing section; and said coating including:
a mixture of chromium and a ceramics material.
10. A heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web, said roll apparatus comprisingl:
a rotable, cylindrical body defining a circumferential outer surface;
a coating applied to said outer surface of said body such that said coating is disposed in pressing contact with the web during said passage of the web through said pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said pressing section; and said coating including:
a mixture of chromium and zirconia.
11. A heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of the web, said roll apparatus comprising:
a rotable, cylindrical body defining a circumferential outer surface;
a coating applied to said outer surface of said body such that said coating is disposed in pressing contact with the web during said passage of the web through said pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said pressing section; and said coating including:
an amorphous alloy including a mixture of iron, chrome and boron.
12. A heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web, said roll apparatus comprising:
a rotable, cylindrical body defining a circumferential outer surface;
a coating applied to said outer surface of said body such that said coating is disposed in pressing contact with the web during said passage of the web through said pressing section, said coating having properties which inhibit sticking of the web to said coating subsequent to said passage of the web through said pressing section; and said coating including:
a matrix of ceramic and Polytetrafluoroethylene.
13. A method of making a heated backing roll apparatus for cooperation with an elongate shoe for defining therebetween an extended pressing section for the passage therethrough of a web, said method comprising the step of:
applying a coating to an outer surface of a rotable, cylindrical body such that in use of the backing roll apparatus, the coating is disposed in pressing contact with the web during passage of the web through the pressing section, the coating having properties which inhibit sticking of the web to the coating subsequent to the passage of the web through the pressing section, the coating including a mixture of chromium and Polytetrafluoroethylene.
14. A method as set forth in claim 13, further including the step of:
abrading the coating prior to use of the backing roll apparatus so that a high percentage of chromium nodules within the mixture of chromium and Polytetrafluoroethylene are exposed with the balance of the mixture between the chromium nodules being Polyfluoroethylene.
15. A method as set forth in claim 14, wherein the abrading step includes:
abrading the coating by a doctor blade pressed into doctoring relationship relative to the coating.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US70614091A | 1991-05-28 | 1991-05-28 | |
| US706,140 | 1991-05-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2065166A1 CA2065166A1 (en) | 1992-11-29 |
| CA2065166C true CA2065166C (en) | 1995-07-18 |
Family
ID=24836371
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2065166 Expired - Fee Related CA2065166C (en) | 1991-05-28 | 1992-04-06 | Heated backing roll apparatus |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH07166490A (en) |
| CA (1) | CA2065166C (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3296710A (en) * | 1965-07-15 | 1967-01-10 | Rice Barton Corp | Absorbent dryer |
| JPS54149787A (en) * | 1978-05-17 | 1979-11-24 | Ichikawa Woolen Textile | Doctor plate |
| FI70273C (en) * | 1985-01-09 | 1986-09-15 | Valmet Oy | SYNTHETIC PRESS RELEASES FOR THE FRAMEWORK OF THE FRAMEWORK |
| EP0289477A3 (en) * | 1987-04-28 | 1989-03-08 | Valmet Paper Machinery Inc. | Method for hot-pressing of a paper web and a drying device for the implementation of the method |
-
1992
- 1992-04-06 CA CA 2065166 patent/CA2065166C/en not_active Expired - Fee Related
- 1992-05-13 JP JP12020092A patent/JPH07166490A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| CA2065166A1 (en) | 1992-11-29 |
| JPH07166490A (en) | 1995-06-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |