WO2004070113A1 - Applicator apparatus of a film-transfer coater and coating method - Google Patents
Applicator apparatus of a film-transfer coater and coating method Download PDFInfo
- Publication number
- WO2004070113A1 WO2004070113A1 PCT/FI2004/000060 FI2004000060W WO2004070113A1 WO 2004070113 A1 WO2004070113 A1 WO 2004070113A1 FI 2004000060 W FI2004000060 W FI 2004000060W WO 2004070113 A1 WO2004070113 A1 WO 2004070113A1
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- WO
- WIPO (PCT)
- Prior art keywords
- dam blade
- dam
- blade
- treatment substance
- applicator
- 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.)
- Ceased
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
- D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
- D21H23/22—Addition to the formed paper
- D21H23/32—Addition to the formed paper by contacting paper with an excess of material, e.g. from a reservoir or in a manner necessitating removal of applied excess material from the paper
- D21H23/34—Knife or blade type coaters
- D21H23/36—Knife or blade forming part of the fluid reservoir, e.g. puddle-type trailing blade or short-dwell coaters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C3/00—Apparatus in which the work is brought into contact with a bulk quantity of liquid or other fluent material
- B05C3/18—Apparatus in which the work is brought into contact with a bulk quantity of liquid or other fluent material only one side of the work coming into contact with the liquid or other fluent material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C11/00—Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00
- B05C11/02—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface
- B05C11/023—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface
- B05C11/025—Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface with an essentially cylindrical body, e.g. roll or rod
Definitions
- the present invention relates to an applicator apparatus according to the preamble of claim 1 for use on the applicator roll of a film-transfer coater.
- the applicator apparatus comprises an application chamber delineated in the rotating direction of the applicator roll by a doctor member and by a dam blade placed upstream of the doctor means in the rotating direction of the applicator roll, means for feeding the web treatment substance into the application chamber and a blade holder suited for mounting the dam blade thereon.
- the invention also relates to a method for applying a web treatment substance onto the applicator roll of a film-transfer coater.
- a web of paper or paperboard can be coated or surface sized using a film-transfer coater, wherein the web being treated is passed through a nip between two opposed rolls.
- the coating furnish or surface size is applied with the help of a suitable applicator apparatus to the surface of one or both of the nip-forming rolls, wherefrom the substance is transferred to the surface of the web being treated in the nip between the rolls.
- the thickness and cross-machine profile of the size layer applied to the roll surface are controlled by a doctor blade or rotatable metering rod.
- the applicator apparatus incorporates an application chamber delineated in the rotating direction of the nip-forming roll on one side by a doctor member and on the other side by the chamber front wall.
- the application chamber is delineated by end wall seals.
- the coating substance or surface size is fed into the application chamber via a duct adapted into the frame beam of the applicator apparatus.
- the volumetric feed rate and pressure of coating furnish into the application chamber are adjusted so high that a baclcflow of coating furnish or surface size is established in a reverse direction to the rotating direction of the applicator roll in the gap between the application chamber front wall and the applicator roll.
- the function of the backflow is to prevent the air boundary layer traveling on the applicator roll surface from entering the application chamber. If allowed to enter the application chamber, such external air may cause uncoated areas on the web.
- the volumetric flow rate of coating furnish must typically be set about 20 to 30 times greater than the amount of furnish adhering to the applicator roll in order to seal the gap completely. Even if the furnish flow rate is set smaller than that needed for sealing the gap with the web treatment substance, the excess flow rate still remains large as compared with that portion thereof forming a film on the applicator roll. In the case the gap is made large, it is not easy to increase the internal pressure of the coating application chamber due to the low flow resis- tance of the wide gap. Hence, an elevated pressure in the application chamber respectively increases the overflow or backflow through the gap.
- the gap between the application chamber front wall and the applicator roll is made very small, e.g., as narrow as 1.5 mm, even minor changes in the gap width due to manufacturing deviations, for instance, will cause cross-machine defects, known as profile errors, in the applied coating. Moreover, reducing the gap width may increase the application chamber pressure so much due to the elevated flow resistance of the narrowed gap width that the sealing of the application chamber edges may become problematic. Furthermore, at very high coater run speeds even the backflow may be insufficient means to prevent the entry of air via the gap between the chamber front wall and the applicator roll into the application chamber where the entrained air can cause turbulence in the web treatment substance.
- the application chamber front wall in a film-transfer coater can be implemented using a so-called dam blade that is pressed against the ap- plicator roll so that air cannot enter the applicator chamber via the gap between the dam blade and the applicator roll.
- dam blade that is pressed against the ap- plicator roll so that air cannot enter the applicator chamber via the gap between the dam blade and the applicator roll.
- coating furnish is anyhow passed through flow openings made in the dam blade from the applicator chamber to in front of the dam blade.
- a pond of lubricating furnish is formed in front of the dam blade thus preventing damage to the applicator roll or the dam blade due to the mutual friction between the dam blade and the applicator roll.
- coating furnish can pass from in front of the dam blade over the dam blade holder back to the coating furnish circulation. Then, the pond of coating furnish in front of the dam blade may grow very large before furnish begins to flow over the dam blade holder. At high web speeds, coating furnish will readily splash from a large pond volume to the surroundings and the applicator roll thus causing inferior quality of coating/size application. Moreover, coating furnish may leak via the clamping groove of the dam blade holder to the exterior side of the applicator chamber.
- the goal of the invention is attained by supporting and pressing the dam blade against the applicator roll by a support member adapted to rest against the rear side of the dam blade.
- the point at which the support member effects its support force is situated approximately midway between the mounting point of the dam blade on its holder and the tip of the dam blade resting against the applicator roll.
- the support member extends over the entire cross-machine length of the dam blade, it prevents web treatment substance contained in the application chamber from escaping to the exterior side of the application chamber via the contact line between the dam blade and the support member under normal loading conditions of the dam blade. In the case that the internal pressure of the application chamber increases, also the force pressing the dam blade against the applicator roll grows.
- the applicator apparatus is characterized by what is stated in the characterizing part of claim 1.
- the coating method according to the invention is characterized by what is stated in the characterizing part of claim 6.
- the invention provides significant benefits.
- the internal pressure of the application chamber cannot grow excessively as the increasing pressure forces the dam blade off from contacting support member thus allowing relief of excessive pressure via the gap between the dam blade and support member.
- This arrangement prevents flexural failing of the dam blade under a transient pressure rise in the application chamber.
- the construction according to the invention is also uncomplicated and easy to implement in existing coaters.
- dam blade between its support point and its mounting point in dam blade holder are made spillway openings that allow web treatment substance accumulating into the pond in front of the dam blade to be passed back to the web treatment substance circulation.
- the volume of the treatment substance pond formed in front of the dam blade is diminished permitting the coater to be run at a higher speed without the risk of splashing. Because the web treatment substance is not any more passed over the dam blade holder back to the treatment substance circulation, the dam blade mounting groove in the dam blade holder stays clean, whereby detrimental chamber leaks of treatment substance via the mounting groove are eliminated.
- FIG. 1 is a schematic side elevation view of a film-transfer coater
- FIG. 2 is a schematic side elevation view of an applicator apparatus according to the invention
- FIG. 3 is a front view of a dam blade suitable for use in an applicator apparatus according to the invention.
- FIG. 4 is a side elevation view of another embodiment of an applicator apparatus according to the invention.
- a film-transfer coater 1 shown therein comprises two rotatable applicator rolls adapted into a nip contact with each other, a first applicator roll 2 and a second applicator roll 3 forming a nip through which a web 4 to be treated by surface size or coating furnish is adapted to pass.
- the travel direction of web 4 is denoted by an arrow.
- a substance for treating the web 4 such as a coating mix or surface size, is applied to the surfaces of applicator rolls 2, 3.
- the treatment substance layer is smoothed and metered to a desired thickness with the help of a doctor member such as a doctor blade or a rotating metering rod.
- the doctored layer of the treatment substance is transferred from the applicator rolls 2, 3 to both sides of the web 4 being treated in the nip between the rolls 2, 3. If only one side of web 4 is to be treated, the treatment substance is metered only on one of the applicator rolls 2, 3.
- the applicator apparatus 5 comprises an applicator chamber 6 delineated by an applicator roll 3.
- the application chamber 6 is delineated by front and rear walls.
- the rotating direction of roll 3 is denoted by an arrow.
- the rear wall of the chamber is formed by a doctor member such as a doctor blade or a smooth- surface or grooved metering rod 7.
- the loading of metering rod 7 is effected by pneumatic inflatable tubes 8.
- the front wall of the chamber is upstream of the rear wall in the rotating direction of the applicator roll.
- the dam blade 9 serves as the chamber front wall.
- the ends of the application chamber 6 are delineated by end wall seals (not shown).
- the application chamber 6 extends in the axial direction of applicator roll 3 over the cross-machine width of the coater.
- the dam blade 9 is mounted at its upper-edge mounting point 10 on a dam blade holder 12 that in turn is mounted on a dam blade support beam 11.
- On the dam blade support beam 11 is also mounted a support member 13 serving to back up the dam blade 9 and to press the same against to the applicator roll 3 so as to prevent the web treatment substance from flowing via the gap between the dam blade 9 and the applicator roll 3 to in front of the dam blade 9.
- the dam blade support point 14 is located between the dam blade tip 15 and the mounting point 10 of the dam blade on the dam blade holder.
- the dam blade support member 13 extends in the axial direction of the applicator roll 3 over the cross-machine width of the application chamber 6.
- the applicator apparatus 5 is mounted in a vertical position such that it operates substantially at the level of a horizontal plane passing through the axial center line of applicator roll 3.
- the web treatment substance is fed via a feed duct 16 adapted to the applicator apparatus frame beam 11 to the application chamber 6, wherefrom the treatment substance is metered to the surface of the applicator roll 3. From the application chamber 6, the web treatment substance is also passed via flow openings 20, which are made to the dam blade 9 on the area thereof between its tip 15 and its support point 14, to in front of the dam blade 9 in order to form there a pond 17 of the web treatment substance.
- the dam blade 9 is provided with spill- way openings 21, via which the excess web treatment substance is passed into a spillway duct 18, that is located behind the dam blade 9 and is delineated by dam blade holder 12, dam blade support member 13 and the portion of dam blade 9 between the dam blade support point 14 and the mounting point 10 of the dam blade 9 on the dam blade holder 12.
- the spillway openings 21 are located within the area of the dam blade 9 situated between the dam blade support point 14 and the mounting point 10 of the dam blade in the dam blade holder 12.
- the spillway openings 21 are made across the width of the application chamber 6 at such a spacing and height that the top level of the web treatment substance pond 17 remains at a desired level below the mounting point 10 of the dam blade on the dam blade holder 12.
- the tip portion of the support member 13 resting against the dam blade 9 is made of rubber or other elastic seal material. Resultingly, the dam blade tip 13 can rest tightly against the dam blade 9 thus preventing any flow of the web treatment substance between the application chamber 6 and the spillway duct 18.
- the web treatment substance pond 17 would extend to the top level of the holder 12 of the dam blade 9, whereupon the web treatment substance could flow over the dam blade holder 12 back into the treatment substance collection trough 19.
- the dam blade 9 If the internal pressure of the application chamber 6 rises excessively high due to, e.g., superfluous feed of web treatment substance, the dam blade 9 is pressed aggressively against the applicator roll 3, whereby the dam blade 9 bends until its contact to the seal tip of dam blade support member 13 is lost and the excessive pressure of application chamber 6 is relieved into the spillway duct 18. After the pressure of application chamber 6 has fallen sufficiently, the dam blade 9 again straightens itself into contact to the sealing tip of the support member. Thus, a flexural failure in the function of the dam blade 9 is avoided that could lead to a transient rise in the internal pressure of application chamber 6.
- the invention may also have embodiments different from those described above.
- the dam blade 9 need not necessarily have the flow openings 20 for passing the web treatment substance to in front of the dam blade 9, but instead, the web treatment substance pond 17 may alternatively be formed using other techniques such as spraying of the web treatment substance from separate nozzles, for instance.
- the embodiment according to the invention may also be applied to such film-transfer coaters in which the rotating direction of the applicator roll 3 is reverse to that of the embodiment shown in FIG. 2. Then, the doctor member 7 is located above the dam blade 9 (FIG. 4), whereby the spillway openings 21 may not necessarily be needed.
Landscapes
- Coating Apparatus (AREA)
Abstract
The invention relates to a method and applicator apparatus (5) for application of a web treatment substance of a paper or paperboard web onto the surface of a rotating applicator roll (3). The applicator apparatus (5) comprises an application chamber (6) delineated in the rotating direction of the applicator roll (3) by a doctor means (7) and a dam blade (9) adapted to operate upstream of the doctor means (7), means (16) for feeding the web treatment substance into the application chamber (6), and a dam blade holder (12) having the dam blade (9) attached thereto. The dam blade (9) is loaded against the applicator roll (3) by support member (13) whose support point (14) is located between the hip (15) of the dam blade (9) and the mounting point (10) of the dam blade on the dam blade holder (12).
Description
Applicator apparatus of a film-transfer coater and coating method
The present invention relates to an applicator apparatus according to the preamble of claim 1 for use on the applicator roll of a film-transfer coater. The applicator apparatus comprises an application chamber delineated in the rotating direction of the applicator roll by a doctor member and by a dam blade placed upstream of the doctor means in the rotating direction of the applicator roll, means for feeding the web treatment substance into the application chamber and a blade holder suited for mounting the dam blade thereon.
The invention also relates to a method for applying a web treatment substance onto the applicator roll of a film-transfer coater.
A web of paper or paperboard can be coated or surface sized using a film-transfer coater, wherein the web being treated is passed through a nip between two opposed rolls. The coating furnish or surface size is applied with the help of a suitable applicator apparatus to the surface of one or both of the nip-forming rolls, wherefrom the substance is transferred to the surface of the web being treated in the nip between the rolls. The thickness and cross-machine profile of the size layer applied to the roll surface are controlled by a doctor blade or rotatable metering rod. The applicator apparatus incorporates an application chamber delineated in the rotating direction of the nip-forming roll on one side by a doctor member and on the other side by the chamber front wall. Laterally the application chamber is delineated by end wall seals. The coating substance or surface size is fed into the application chamber via a duct adapted into the frame beam of the applicator apparatus. The volumetric feed rate and pressure of coating furnish into the application chamber are adjusted so high that a baclcflow of coating furnish or surface size is established in a reverse direction to the rotating direction of the applicator roll in the gap between the application chamber front wall and the applicator roll. The function of the backflow is to prevent the air boundary layer traveling on the applicator roll surface from entering the application chamber. If allowed to enter the application chamber, such external air may cause uncoated areas on the web.
As the gap between the applicator roll and the application chamber front wall generally is in the range of 3-6 mm, the volumetric flow rate of coating furnish must typically be set about 20 to 30 times greater than the amount of furnish adhering to the applicator roll in order to seal the gap completely. Even if the furnish flow rate is set smaller than that needed for sealing the gap with the web treatment substance, the excess flow rate still remains large as compared with that portion thereof forming a film on the applicator roll. In the case the gap is made large, it is not easy to increase the internal pressure of the coating application chamber due to the low flow resis- tance of the wide gap. Hence, an elevated pressure in the application chamber respectively increases the overflow or backflow through the gap. If the gap between the application chamber front wall and the applicator roll is made very small, e.g., as narrow as 1.5 mm, even minor changes in the gap width due to manufacturing deviations, for instance, will cause cross-machine defects, known as profile errors, in the applied coating. Moreover, reducing the gap width may increase the application chamber pressure so much due to the elevated flow resistance of the narrowed gap width that the sealing of the application chamber edges may become problematic. Furthermore, at very high coater run speeds even the backflow may be insufficient means to prevent the entry of air via the gap between the chamber front wall and the applicator roll into the application chamber where the entrained air can cause turbulence in the web treatment substance.
To increase the coater run speed, the application chamber front wall in a film-transfer coater can be implemented using a so-called dam blade that is pressed against the ap- plicator roll so that air cannot enter the applicator chamber via the gap between the dam blade and the applicator roll. While no actual backflow takes place past the dam blade facing the applicator roll, coating furnish is anyhow passed through flow openings made in the dam blade from the applicator chamber to in front of the dam blade. Hereby, a pond of lubricating furnish is formed in front of the dam blade thus preventing damage to the applicator roll or the dam blade due to the mutual friction between the dam blade and the applicator roll. If the dam blade of the applicator apparatus is situated higher than the actual doctoring member, coating furnish can
pass from in front of the dam blade over the dam blade holder back to the coating furnish circulation. Then, the pond of coating furnish in front of the dam blade may grow very large before furnish begins to flow over the dam blade holder. At high web speeds, coating furnish will readily splash from a large pond volume to the surroundings and the applicator roll thus causing inferior quality of coating/size application. Moreover, coating furnish may leak via the clamping groove of the dam blade holder to the exterior side of the applicator chamber.
If the internal pressure of the application chamber increases due to, e.g., excessive feed of coating furnish, also the force pressing the dam blade against the applicator roll increases thus causing higher wear rate of the dam blade and possibly damaging the applicator roll.
It is an object of the present invention to provide for a film-transfer coater an entirely novel kind of applicator apparatus with a relief facility of the dam blade loading.
The goal of the invention is attained by supporting and pressing the dam blade against the applicator roll by a support member adapted to rest against the rear side of the dam blade. The point at which the support member effects its support force is situated approximately midway between the mounting point of the dam blade on its holder and the tip of the dam blade resting against the applicator roll. The support member extends over the entire cross-machine length of the dam blade, it prevents web treatment substance contained in the application chamber from escaping to the exterior side of the application chamber via the contact line between the dam blade and the support member under normal loading conditions of the dam blade. In the case that the internal pressure of the application chamber increases, also the force pressing the dam blade against the applicator roll grows. If the internal pressure of the applicator chamber increases above a certain level, the dam blade bends and thus looses its contact to support member. Hereby, the excess pressure of the application chamber is relieved via the gap between the dam blade and support member. After the application chamber pressure has been relieved sufficiently, the dam blade again assumes its resting position against support member.
More specifically, the applicator apparatus according to the invention is characterized by what is stated in the characterizing part of claim 1.
Furthermore, the coating method according to the invention is characterized by what is stated in the characterizing part of claim 6.
The invention provides significant benefits.
The internal pressure of the application chamber cannot grow excessively as the increasing pressure forces the dam blade off from contacting support member thus allowing relief of excessive pressure via the gap between the dam blade and support member. This arrangement prevents flexural failing of the dam blade under a transient pressure rise in the application chamber. The construction according to the invention is also uncomplicated and easy to implement in existing coaters.
In a preferred embodiment of the invention, on the dam blade between its support point and its mounting point in dam blade holder are made spillway openings that allow web treatment substance accumulating into the pond in front of the dam blade to be passed back to the web treatment substance circulation. As a result, the volume of the treatment substance pond formed in front of the dam blade is diminished permitting the coater to be run at a higher speed without the risk of splashing. Because the web treatment substance is not any more passed over the dam blade holder back to the treatment substance circulation, the dam blade mounting groove in the dam blade holder stays clean, whereby detrimental chamber leaks of treatment substance via the mounting groove are eliminated.
In the following, the invention is examined in more detail with the help of the appended drawings in which
FIG. 1 is a schematic side elevation view of a film-transfer coater;
FIG. 2 is a schematic side elevation view of an applicator apparatus according to the invention;
FIG. 3 is a front view of a dam blade suitable for use in an applicator apparatus according to the invention; and
FIG. 4 is a side elevation view of another embodiment of an applicator apparatus according to the invention.
Referring to FIG. 1, a film-transfer coater 1 shown therein comprises two rotatable applicator rolls adapted into a nip contact with each other, a first applicator roll 2 and a second applicator roll 3 forming a nip through which a web 4 to be treated by surface size or coating furnish is adapted to pass. The travel direction of web 4 is denoted by an arrow. With the help of applicator apparatuses 5, a substance for treating the web 4, such as a coating mix or surface size, is applied to the surfaces of applicator rolls 2, 3. The treatment substance layer is smoothed and metered to a desired thickness with the help of a doctor member such as a doctor blade or a rotating metering rod. The doctored layer of the treatment substance is transferred from the applicator rolls 2, 3 to both sides of the web 4 being treated in the nip between the rolls 2, 3. If only one side of web 4 is to be treated, the treatment substance is metered only on one of the applicator rolls 2, 3.
Referring to FIG. 2, the construction of the applicator apparatus 5 of the second applicator roll 3 is therein described in more detail. The applicator apparatus 5 comprises an applicator chamber 6 delineated by an applicator roll 3. In the rotating direction of the applicator roll 3, the application chamber 6 is delineated by front and rear walls. The rotating direction of roll 3 is denoted by an arrow. The rear wall of the chamber is formed by a doctor member such as a doctor blade or a smooth- surface or grooved metering rod 7. The loading of metering rod 7 is effected by pneumatic inflatable tubes 8. The front wall of the chamber is upstream of the rear wall in the rotating direction of the applicator roll. The dam blade 9 serves as the chamber front wall. The ends of the application chamber 6 are delineated by end wall
seals (not shown). The application chamber 6 extends in the axial direction of applicator roll 3 over the cross-machine width of the coater. The dam blade 9 is mounted at its upper-edge mounting point 10 on a dam blade holder 12 that in turn is mounted on a dam blade support beam 11. On the dam blade support beam 11 is also mounted a support member 13 serving to back up the dam blade 9 and to press the same against to the applicator roll 3 so as to prevent the web treatment substance from flowing via the gap between the dam blade 9 and the applicator roll 3 to in front of the dam blade 9. The dam blade support point 14 is located between the dam blade tip 15 and the mounting point 10 of the dam blade on the dam blade holder. The dam blade support member 13 extends in the axial direction of the applicator roll 3 over the cross-machine width of the application chamber 6. The applicator apparatus 5 is mounted in a vertical position such that it operates substantially at the level of a horizontal plane passing through the axial center line of applicator roll 3.
The web treatment substance is fed via a feed duct 16 adapted to the applicator apparatus frame beam 11 to the application chamber 6, wherefrom the treatment substance is metered to the surface of the applicator roll 3. From the application chamber 6, the web treatment substance is also passed via flow openings 20, which are made to the dam blade 9 on the area thereof between its tip 15 and its support point 14, to in front of the dam blade 9 in order to form there a pond 17 of the web treatment substance.
To prevent the volume of the web treatment substance pond 17 formed in front of the dam blade 9 from growing excessively large, the dam blade 9 is provided with spill- way openings 21, via which the excess web treatment substance is passed into a spillway duct 18, that is located behind the dam blade 9 and is delineated by dam blade holder 12, dam blade support member 13 and the portion of dam blade 9 between the dam blade support point 14 and the mounting point 10 of the dam blade 9 on the dam blade holder 12. Respectively, the spillway openings 21 are located within the area of the dam blade 9 situated between the dam blade support point 14 and the mounting point 10 of the dam blade in the dam blade holder 12. The spillway openings 21 are made across the width of the application chamber 6 at such a spacing and height that
the top level of the web treatment substance pond 17 remains at a desired level below the mounting point 10 of the dam blade on the dam blade holder 12.
The tip portion of the support member 13 resting against the dam blade 9 is made of rubber or other elastic seal material. Resultingly, the dam blade tip 13 can rest tightly against the dam blade 9 thus preventing any flow of the web treatment substance between the application chamber 6 and the spillway duct 18.
With no spillway openings made in dam blade 9, the web treatment substance pond 17 would extend to the top level of the holder 12 of the dam blade 9, whereupon the web treatment substance could flow over the dam blade holder 12 back into the treatment substance collection trough 19.
If the internal pressure of the application chamber 6 rises excessively high due to, e.g., superfluous feed of web treatment substance, the dam blade 9 is pressed aggressively against the applicator roll 3, whereby the dam blade 9 bends until its contact to the seal tip of dam blade support member 13 is lost and the excessive pressure of application chamber 6 is relieved into the spillway duct 18. After the pressure of application chamber 6 has fallen sufficiently, the dam blade 9 again straightens itself into contact to the sealing tip of the support member. Thus, a flexural failure in the function of the dam blade 9 is avoided that could lead to a transient rise in the internal pressure of application chamber 6.
The invention may also have embodiments different from those described above.
The dam blade 9 need not necessarily have the flow openings 20 for passing the web treatment substance to in front of the dam blade 9, but instead, the web treatment substance pond 17 may alternatively be formed using other techniques such as spraying of the web treatment substance from separate nozzles, for instance. The embodiment according to the invention may also be applied to such film-transfer coaters in which the rotating direction of the applicator roll 3 is reverse to that of the embodiment shown in FIG. 2. Then, the doctor member 7 is located above the dam
blade 9 (FIG. 4), whereby the spillway openings 21 may not necessarily be needed.
Claims
1. An applicator apparatus (5) of a film-transfer coater for application of a web treatment substance of a paper or paperboard web (4) onto the surface of a rotating applicator roll (3), the applicator apparatus (5) comprising
- an application chamber (6) delineated in the rotating direction of the applicator roll (3) by a doctor means (7) and a dam blade (9) placed upstream of the doctor means (7),
- means (16) for feeding the web treatment substance into the application chamber (6), and
- a dam blade holder (12) having the dam blade (9) attached thereto,
characterized by
- support member (13) for supporting the dam blade (9) against the applicator roll (3), the support point (14) of said support member (13) being located between the tip (15) of the dam blade (9) and the mounting point (10) of the dam blade on the dam blade holder (12).
2. The applicator apparatus (5) of claim 1, characterized by means for passing web treatment substance to in front of the dam blade (9).
3. The applicator apparatus (5) of claim 2, characterized in that said means for passing the web treatment substance to in front of the dam blade (9) comprise flow openings (20) made in the dam blade (9) over the area thereof extending from the dam blade tip (15) to the dam blade support point (14).
4. The applicator apparatus (5) of claim 2 or 3, characterized by spillway openings (21) made in the dam blade (9) for drainage of excess web treatment substance away from in front of the dam blade (9), said spillway openings (21) being located over the dam blade area extending from the dam blade support point (14) to the mounting point (10) of said dam blade (9) on the dam blade holder (12).
5. The applicator apparatus (5) of any one of claims 1-4, characterized in that said blade support members (13) comprise a seal member adapted to function against said dam blade (9).
6. A method for applying a web treatment substance of a paper or paperboard web (4) onto the surface of a rotating applicator roll (3), the method comprising the steps of
- feeding the web treatment substance into an application chamber (6) delineated in the rotating direction of the applicator roll (3) by a doctor means (7) and a dam blade (9) that is placed upstream of the doctor means
(7) and is mounted on a dam blade holder (12),
characterized in that
- the dam blade (9) is supported against the applicator roll (3) at a support point (14) located between the tip (15) of the dam blade (9) and the mounting point (10) of the dam blade on the dam blade holder (12).
7. The method of claim 6, characterized in that the web treatment substance is passed to in front of the dam blade (9) .
8. The method of claim 1, characterized in that the web treatment substance is passed from the application chamber (6) to in front of the dam blade (9) via flow openings (20) made in the dam blade (9) over the area thereof extending from the dam blade tip (15) to the dam blade support point (14).
9. The method of claim 7 or 8, characterized in that the web treatment substance is drained from in front of said dam blade (9) via spillway openings (21) made in said dam blade (9), said spillway openings (21) being located over the dam blade area extending from the dam blade support point (14) to the mounting point (10) of said dam blade (9) on the dam blade holder (12).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI20030199 | 2003-02-10 | ||
| FI20030199A FI113976B (en) | 2003-02-10 | 2003-02-10 | Application device for a film transfer coating device and coating method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2004070113A1 true WO2004070113A1 (en) | 2004-08-19 |
Family
ID=8565584
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FI2004/000060 Ceased WO2004070113A1 (en) | 2003-02-10 | 2004-02-09 | Applicator apparatus of a film-transfer coater and coating method |
Country Status (2)
| Country | Link |
|---|---|
| FI (1) | FI113976B (en) |
| WO (1) | WO2004070113A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3023163A1 (en) * | 2014-11-18 | 2016-05-25 | Valmet Technologies, Inc. | Sealing blade |
| US9925555B2 (en) | 2016-02-08 | 2018-03-27 | Valmet Technologies, Inc. | Folded sealing blade for a coating applicator |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0319503A2 (en) * | 1987-12-03 | 1989-06-07 | Valmet Paper Machinery Inc. | Method and device for application and dosage of coating material onto a moving base |
| US5376177A (en) * | 1993-08-09 | 1994-12-27 | Macmillan Bloedel Limited | Coat weight profiling |
| US5858090A (en) * | 1994-12-15 | 1999-01-12 | Voith Sulzer Papiermaschinen Gmbh | Apparatus for the application of a liquid or pasty medium onto a moving material web, in particular of paper or board |
| WO1999060210A1 (en) * | 1998-05-20 | 1999-11-25 | Valmet Corporation | Applicator apparatus and method for film-transfer coating |
-
2003
- 2003-02-10 FI FI20030199A patent/FI113976B/en active
-
2004
- 2004-02-09 WO PCT/FI2004/000060 patent/WO2004070113A1/en not_active Ceased
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0319503A2 (en) * | 1987-12-03 | 1989-06-07 | Valmet Paper Machinery Inc. | Method and device for application and dosage of coating material onto a moving base |
| US5376177A (en) * | 1993-08-09 | 1994-12-27 | Macmillan Bloedel Limited | Coat weight profiling |
| US5858090A (en) * | 1994-12-15 | 1999-01-12 | Voith Sulzer Papiermaschinen Gmbh | Apparatus for the application of a liquid or pasty medium onto a moving material web, in particular of paper or board |
| WO1999060210A1 (en) * | 1998-05-20 | 1999-11-25 | Valmet Corporation | Applicator apparatus and method for film-transfer coating |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3023163A1 (en) * | 2014-11-18 | 2016-05-25 | Valmet Technologies, Inc. | Sealing blade |
| CN105603822A (en) * | 2014-11-18 | 2016-05-25 | 维美德技术有限公司 | Sealing blade |
| US9925555B2 (en) | 2016-02-08 | 2018-03-27 | Valmet Technologies, Inc. | Folded sealing blade for a coating applicator |
Also Published As
| Publication number | Publication date |
|---|---|
| FI113976B (en) | 2004-07-15 |
| FI20030199A0 (en) | 2003-02-10 |
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