WO2011016767A1

WO2011016767A1 - Method and device for exchange of coater blade in a coating machine

Info

Publication number: WO2011016767A1
Application number: PCT/SE2010/050688
Authority: WO
Inventors: Kjell Larsson
Original assignee: Kjell Larsson
Priority date: 2009-08-03
Filing date: 2010-06-18
Publication date: 2011-02-10
Also published as: SE534017C2; SE0950577A1

Abstract

To reduce the production fall that occurs at manual shifting of individual coating blades in a device for coating of a paper or board web, the blade (5) is removed in the cross direction from the blade holder unit (3) by gripping means (8), which thereupon also move the new blade (5) to and insert it in the blade holder unit (3). Preferably, the shifting sequence is carried out automatically, at least in part, and it suitable that a securing device (31) for the blade (5) to be shifted included in the blade holder unit (3) is cleaned by washing (9) with washing agent, e.g. water, before the removal of the blade (5). Preferably the gripping means (8) fetch the blade (5) from a cartridge (10), which also may be used for transporting the blades (5) to and from the coater, and a shifting unit (7) is arranged to move the gripping means (8) in the cross direction away from and toward the blade holder unit (3), vertically as well as horizontally.

Description

Method and device for exchange of coater blade in a coating machine

DESCRIPTION

TECHNICAL FIELD

The present invention relates to a method of shifting during operation a coating blade held in a blade holder unit in a device for coating a paper or board web, wherein the blade holder unit is being moved so as to cause the blade to cease bearing against the web, whereupon the blade is removed from the blade holder unit, and that thereafter a new blade is mounted in the blade holder unit and caused to bear against the web by movement of the blade holder unit. The invention also relates to a device for shifting during operation a coating blade held in a blade holder unit in a device for coating a paper or board web.

The term "individual" coating elements denotes coating elements having a length that in a broad outline corresponds to the width of the coated web.

In the present context, the term "coating blade" is to be understood as including all individual coating elements including roller blades and other doctors and elements that are used for finally dosing a surplus of coating colour applied to a web to form a coating layer having the desired properties.

Further, the term "move" denotes a movement of the blade position between an operating position and a position, where the blade can be shifted.

TECHNICAL BACKGROUND

When manufacturing coated paper or board the coating blade has to be shifted at regular intervals, because it is subjected to wear that gradually causes a reduction of the quality of the coated web. Shifting of individual blades is usually carried out by moving the blade holder unit, e.g. by swinging or turning it away, from a counter roll that carries the web during the coating, so that the blade can be removed manually from its clamped position in the blade holder unit. During the shifting operation, the web continues running and becomes what is called broke, which is sorted out and returned to the manufacturing process. The coating blade and the blade holder unit are cleaned manually. A new coating blade is fetched manually, is placed in the blade holder unit and clamped tight, whereupon the blade holder unit is moved (e.g. turned or swung) back, so that the new blade contacts the web and the coating can be resumed. The time required for the shifting operation depends on how wide the coater is and how many personnel do the work, but the interruption of the coating operation leads to high costs. Further, the manual handling of long razor-sharp coating blades during stressing conditions give rise to high risk of injuries.

To do something about these disadvantages, it has been suggested not to use individual coating blades but instead use continuous strip-shaped coating blades, which are unwound from a supply reel on one side of the coater, extend across the web to be coated, and then wound onto a roll on the other side of the machine. When the wear of the coating blade strip portion momentarily used has become so large that it is time for a "shift'^", an unused portion of the strip is fed from the supply reel across the cross direction of the web, while the used portion is being wound on the other roll. For an illustrative example of equipment and methods of this kind, we refer to US

6 068 272, which describes a movable container for storing and transporting wound flexible strip-shaped coating blades, WO 2004/081283 Al and WO 02/099189 Al that describe flexible strip-shaped coating blades in reels, WO 2006/108922 Al that describes a device for cutting worn out flexible strip-shaped coating blades, WO 01/04414 Al that describes a carriage for winding and storing used flexible strip-shaped coating blades, EP 1 149 948 A2 that describes automatic cleaning and grinding of flexible strip-shaped coating blades, which are reeled in their longitudinal direction, and DE 200 12 140 Ul that describes a device for extracting and cleaning of flexible strip-shaped coating blades, which are reeled in their longitudinal direction.

A device for shifting individual coating blades is described in US 3 070 461. At the shifting operation, a new coating blade is brought to bear against the web, which is supported by a counter roll, in a position downstream of the coating blade that is to be shifted and is in operating position. Thereafter, the used blade is withdrawn from the web, the new blade is moved during continuous operational contact with the web to the operational position of the old blade, whereupon the new blade is fixed in that position. In this manner, a continuous coating during the blade shifting is made possible, and no part of the web has to be rejected as broke. A disadvantage of this device is that it is mechanically complicated and is not suitable for rebuilding existing coaters.

The Japanese patent publication JP 20011052335 (A) describes a device for shifting blades, which are to doctor off a surplus of magnetic coating from an information storing tape. The tape runs obliquely upward with the coating on its bottom side, and a rotary blade head with generally vertical rotary axis has at least two diametrically opposed blades located in the horizontal plane, one of which doctors off the surplus from the tape, while the other constitutes a spare blade that is turned forward when it is time for a blade shift. Such a design is suitable for narrow tapes but cannot be applied for paper and board webs, where the individual blades have a length of several meters.

Further, in US 2003/0150479 Al there is described a blade cleaner, which comprises a protective handle and a cleaning track having an interior coating of abrasive or final cleaning material. The blade cleaner is pushed in over the blade edge and is then manually or by some automatic system pulled along the blade for mechanical cleaning thereof.

SUMMARY OF THE INVENTION

The main object of the present invention is to reduce the fall in production that arises at manual shifting of individual coating blades in a device for coating of a paper or board web.

In a method of the kind stated in the first paragraph above, this object is achieved in that in accordance with the present invention the blade is removed from the blade holder unit, preferably in a cross direction from the blade holder unit, by gripping means, which thereupon also move the new blade to and place it in the blade holder unit.

Further, said object is achieved in a device of the kind stated in the second paragraph above, in that in accordance with the present invention gripping means are arranged to grip the blade, remove it, preferably in its cross direction, from the blade holder unit, and deliver it at a predetermined place, and thereupon also to grip the new blade, move it to and place it in the blade holder unit.

Hereby, the shifting procedure advantageously may be arranged to be carried out automatically, at least in part, whereby many advantages are gained, above all increased production of coated web, but also a saving of energy, in that a reduced amount of paper or board will be returned as broke. Also the number of persons required for the shifting can be reduced, as there usually are several coaters in a coating line and dependent on the width of the coater one to two men per coater is required. In addition, the safety of the personnel will increase when they don't have to handle razor-sharp blades in stressing situations. Instead of being included in a separate coating line, the coater can, of course, be arranged at the end of the dry end of a paper or board machine. The blade holder unit suitably comprises a blade securing device for securing the coating blade, and a beam on which the blade securing device is mounted.

The securing device for the blade to be shifted suitably is cleaned by washing with a cleaning agent, e.g. water, before removal of the blade. By removing the coating colour to the extent possible from the securing device before the colour has had time to dry. the mounting of the new coating blade in correct position in the securing device is facilitated. The washing advantageously is included in the automatic shifting procedure. The gripping means, which, as a matter of course, are adapted to the coating blades in question, suitably fetch the blade from a holder, e.g. a cartridge. The cartridge can also be used for receiving the used coating blade and can constitute transport case for a plurality of coating blades, which one after the other will be used in the coating device. Thus, the cartridge has room for at least two coating blades and contains at least one new coating blade, and it is arranged parallel with the blade holder unit for receiving the blade removed from the blade holder unit and delivering said new coating blade to the gripping means. Further, the cartridge is carried by the blade holder unit or is arranged adjacent thereto.

It is suitable, that a shifting unit is arranged to move the gripping means, suitably in the cross direction, from and toward the blade holder unit, in vertical direction as well as in horizontal direction, and the shifting unit can be driven pneumatically, hydraulically, or electrically.

The shifting device preferably comprises a top frame, which carries the shifting unit for moving the gripping means, and the top frame in its turn is carried either by link arms that support the blade holder unit pivotally or by a floor that supports the coating device.

Suitably, the coating blade grip of the gripping means is provided pneumatically, hydraulically, electrically, magnetically, or by vacuum.

Further, the shifting device preferably comprises a washing unit, which at blade shifting automatically cleans the blade securing device. The washing unit suitably comprises a washing head that can travel along the blade securing device and has nozzles for a cleansing agent, e.g. water and/or air. It is suitable that the washing head is carried by a carriage, which can be driven to travel on a guide rail that is parallel to the blade securing device and is mounted on said top frame. Further, the washing head suitably is arranged to be movable in toward and away from the blade securing device, usually downward and upward. Another object of the present invention is to facilitate the handling of coating blades that are being removed from a blade holder unit in a device for coating of a paper or board web. In accordance with the present invention, this object is achieved in that a device for cleaning of a coating blade and preferably its mounting in a device for coating of a paper or board web comprises a washing head that can travel along the coating blade and has nozzles for a cleansing agent, e.g. water and/or air. By removing the coating agent as far as possible from the securing device before the binder has had time to dry, the insertion of the new blade in correct position in the blade securing device is facilitated. It is also suitable to clean also the blade that is to be shifted, primarily in order not to transfer coating agent to the gripping means, which otherwise could contaminate the new blade.

BRIEF DESCRIPTION OF THE APPENDED DRAWINGS

In the following, the invention will be described more in detail with reference to preferred embodiments and the appended drawings.

Fig. 1 is an end view of a first preferred embodiment of a blade shifting device according to the invention for a device for coating a paper or board web, where the coating blade in operating position bears against the web that is supported by a counter roll.

Fig. 2 is an end view similar to Fig. 1 , but with the blade holder unit swung out from the counter roll, so that the coating blade is free from contact with the web. Fig. 3 is a sketchy enlarged perspective view of part of the device of Fig. 2 and shows gripping means, which carried and moved by a shifting unit grip a coating blade to remove it from the blade holder unit.

Fig. 4 is a view similar to the one of Fig. 3 and shows on one hand how the gripping

means assisted by the shifting unit deliver the used blade into a cartridge and on the other hand how a washing unit having a washing head with nozzles is lowered down to an end of a blade holder included in the blade holder unit.

Fig. 5 is an end view, partly in cross-section, of an upper portion of a top frame included in the blade shifting device.

Fig. 6 is a side view of the top frame and its fastening to the blade holder unit. Fig. 7 is a sketchy side view of gripping means and a moving and shifting unit for the gripping means carried by the top frame.

Fig. 8 is a simple sketch showing the claws of the gripping means adapted for gripping a roller blade.

Fig. 9 is a schematic end view of the washing unit.

Fig. 10 is a side view of a carriage included in the washing unit.

Fig. 11 is an end view of a second preferred embodiment of a blade shifting device

according to the invention, wherein the top frame is carried from the floor on which the coating device is standing. Fig. 12 is a schematic end view of a variant comprising a cartridge feeding device and a cooperating blade holder unit.

Fig. 13 is a schematic side view of a variant of shifting unit, where the actuator or linear unit that moves the gripping means vertically is pivotally attached to the linear unit that moves them horizontally.

Fig. 14 is a schematic end view of a prior art device for coating a paper or board web, where the coating blade in its operating position bears against the web that is supported by a counter roll.

Fig. 15 is a schematic end view of the device of Fig. A, but with the coating blade swung out from its operation position, so that it does not bear against the web but can be shifted. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Figs. A and B show a conventional device for coating a running paper web or board web 1, which normally has a width of several meters and is supported by a rotary counter roll 2 carried in two bearing pedestals 21, one of which is shown in the figures. A blade holder unit 3, which is holding a coating blade 5, is pivotally carried by two angular levers 4, so that the coating blade 5 can be brought to bear against the web 1 supported by the counter roll 2 and be moved away from the web. The pivoting of the blade holder unit 3 between the operating position of the blade 5 and its disengaged position is carried out by means of an actuator 41, e.g. a pneumatic or hydraulic piston and cylinder assembly, for each of the levers 4. In the shown embodiment, each angular lever 4 has a knee, which is provided with a joint 42 located coaxially with the tip of the coating blade 5, what makes it possible to set a desired blade angle by rotating the blade 5 around its tip. Coating colour is supplied to the web at a position, not shown, upstream of the blade 5, usually at the lowest point of the counter roll 2, and the blade 5 scrapes off a surplus of the slip from the web 1.

As the blade 5 is exposed to wear, which gradually causes a reduction of the quality of the coated web 1, it has to be shifted, replaced, at regular intervals. To carry out the shifting, the blade holder unit 3 is swung out, so that the coating blade 5 arrives at its disengaged position and can be loosened manually from its clamped position in the blade holder unit 3. During the shifting operation, the web 1 runs on and forms what is known as broke, which is sorted out and returned to the manufacturing process. The coating blade 5 and the blade holder unit 3 are cleaned manually. A new coating blade is fetched manually, placed in the blade holder unit 3 and clamped in place, whereupon the blade holder unit is swung back, so that the new blade 5 bears against the web 1 and the coating can be resumed. The time expenditure for the shifting operation is dependent on the width of the coater and on the number of persons carrying out the work.

Figs. 1-10 show a preferred embodiment of a device for shifting a coating blade, which device reduces the fall in production that arises at manual shifting and reduces the risk of personal injuries. The device is shown applied to the coater of Figs. A and B, and the reference numerals used therein are used also below.

According to the invention, gripping means 8 are arranged to grip the blade 5, remove it from the blade holder unit 3, preferably in its cross direction from the blade holder unit 3, and deliver it at a predetermined place, and thereupon also to grip the new blade 5, move it to and place it in the blade holder unit 3, which comprises a blade holder beam 32 with beam ends 33 and a conventional blade securing device 31 for the blade 5. The cross direction of the blade holder unit 3 shall be interpreted to mean the direction extending ^' perpendicularly to the longitudinal axis of the blade holder unit 3, which longitudinal axis is essentially parallel to the width of the paper web and the axis of the counter roll. A shifting unit 7, which is driven pneumatically, hydraulically, or electrically, is arranged to move the gripping means 8 away from and toward the blade holder unit 3, vertically as well as horizontally. The shifting unit 7, which is best shown in Fig. 7, comprises at least one linear unit 71 for linear movement of the gripping means 8 horizontally, at least one actuator or linear unit 73 for vertical movement, and a cross beam 74, along which the gripping means 8 are placed. The gripping means 8 comprise gripping claws 81 that are adapted to the type of coating blade 5 that is to be shifted. As an illustrative example, Fig. 8 shows how the claws 81 are adapted to a blade 5 having a rotary rod at its tip. It will be realized that the grip of the gripping means 8 in the coating blade 5 may be attained pneumatically, hydraulically, electrically, or magnetically, or by vacuum. The shifting unit 7 is carried by a top frame 6 and has a hold 72 for making contact with the top frame. In the shown embodiment, vide especially Figs. 5 and 6, the top frame 6 comprises a cross beam formed by three parallel frame tubes 60 arranged in a triangular shape and two end plates 61. At least on its top side, the cross beam is clad with sheet metal 66. Each of the two end plates 61 is connected by an individual essentially vertical beam 62 to a respective end 33 of the blade holder beam 32, so that the frame 6 and the shifting unit with the gripping means 8 accompany the blade holder unit 3 when it is moved. A carrier 65 for each linear unit 71 in the shifting unit 7 is attached along the rear long side of the cross beam. A guide rail 63 is attached along the front long side, which is located closest to the counter roll 2. The guide rail is provided with a longitudinal rack 64.

A washing unit 9, which is best shown in Figs. 9 and 10, and which at a blade shifting operation automatically cleans the blade securing device 31, comprises a carriage 91, which can travel along the blade securing device 31, and a washing head 90 carried by the carriage 91 and having nozzles 97 and splash guards 98 for a cleaning agent, e.g. water and/or air. (It is realized that also fluid of other kind may be used for satisfying the desired cleansing effect.) The carriage 91 is provided with wheels 92 engaging the guide rail 63 and is driven by a motor 93 provided with a pinion 94 that meshes with the rack 64. The washing head 90 is suspended from a piston rod 96 of a piston and cylinder assembly 95 carried by the carriage 91, so that the washing head 90 is movable in toward and away from the blade securing device 31, in the embodiment shown in the figures downward and upward, respectively. If desired, the washing head 90 can first wash the blade securing device 31 and the coating blade 5 fixed therein, and after removal of the blade 5 carry out another washing of the now empty blade securing device 31. A cartridge 10, which has room for at least two coating blades 5 and contains at least one new coating blade, is provided parallel with the blade holder unit 3 for receiving the blade removed from the blade holder unit and delivering said new coating blade 5 to the gripping means 8. Along its length, the cartridge is provided with a plurality of transverse blade supports 101 of hair comb type, where the comb teeth keep the individual blades 5 separated from one another. The comb teeth are of such size that the space between the individual blades 5 will be sufficient to permit gripping by the gripping means 8 on lifting individual blades up from and lowering individual blades down into the cartridge 10. To avoid a possible erroneous mounting of a new blade, all of the blades in the cartridge have the same orientation. In the embodiment shown in Figs. 1—4, the cartridge 10 is carried by a bracket 102 on the blade holder unit 3, but as will be evident below, it may optionally be located beside it. In Fig. 1, the blade shifting device of the invention is shown in its normal resting position during operation of the coater. The shifting unit 7 is in its rear position, to the left in the figure, and the washing unit 9 is located beyond the far end of the counter roll 2. hi Fig. 2, the coating is temporarily stopped, but the web 1 continues to run. and the blade 5 is removed from the web 1, so that the washing unit 9 can carry out the cleaning and the gripping means 8 can remove the used blade and insert a new one in the blade holder unit 3. hi Fig. 3, there is shown that the blade holder unit may comprise two parallel cooperating horizontal linear units 71, each of which at its front end, i.e. nearest the counter roll 2, has a vertical actuator or linear unit 73, and the units 73 carry a common cross beam 74, on which the gripping means 8 are mounted. The gripping means 8 are shown gripping a blade 5 that is being put down into or lifted up out of the blade securing device 31. hi Fig. 4. the shifting unit has been run back toward its rear end position, to the left in the figure, and the gripping means 8 are shown gripping a blade 5 that is being put down into or lifted up out of the cartridge 10. Further, the piston and cylinder assembly 95 has lowered the washing head 90 to a position where it can carry out its washing function when moving along the blade securing device 31.

A control system, not shown, may be provided for carrying out the various steps at the blade shifting including the washing. Consequently, a control unit, not shown, controls the actuators 41 for engaging and disengaging the coater blade 5, moving and maneuvering the washing unit 9 with the drive motor 93 and the piston and cylinder assembly 95 and not shown valves for cleaning agent, e.g. water and possible air, to the nozzles 97, moving and maneuvering the switching unit 7 with the linear units 71 and actuators or linear units 73, loosening and fastening the coating blade 5 in the blade securing device 31, and opening and closing the gripping means 8 with the gripping claws 81.

To make the blade shifting device adaptable to other coaters than of the type shown in Figs. A, B, and 1-4, some parts may have to be shaped in another way than what is described above. For example, instead of being carried by the blade holder unit 3 as shown in Fig. 11, the frame 6 may be placed outside the ends of the blade holder unit 3 and be carried directly from the floor, on which the coating device is standing. The frame 6 has a hinge point 67, which is aligned with the tip of the blade 5 and the observation opening 42 in the lever 4 when the blade holder unit 3 is in disengaged position. At its back part (to the left in the figure), the top portion of the frame 6 can be raised and lowered by means of at least one actuator 68 and suitably has a probe, not shown, against the blade holder unit 3, so that the top portion in a lowered position will assume the same angle as the one the blade holder 3 has. Such a probe may be a mechanical stop or some conventional sensor. In the embodiment shown in Fig. 12, the cartridge 10 is not carried by the blade holder unit 3 but is placed outside thereof. In the shown design solution, a vertical linear unit 103 is placed outside each end of the blade holder unit 3. These linear units 103 cooperate and move the cartridge 10 upward and downward, and the cartridge 10 is suspended from the two linear units 103 with a central shaft 104. When the linear units 103 lift the cartridge 10 up to the blade holder unit 3, which is in its disengaged position, the cartridge is guided to correct angle and level by projections 105 from the shaft 104 or the cartridge ends and by stops 34 provided on the blade holder unit 3. Such stops 34 may be located on the ends 33 of the blade holder unit 3. If desired, the linear units 103 may be used also for transporting cartridges into and out of the blade shifting device.

Further, if desired and as shown in Fig. 13, the actuators or linear units 73 in the shifting unit 7 may be pivotally attached to the respective linear unit 71 by a hinge 75 and the pivotal movement controlled by at least one actuator 76. In this way, more space is created for the operators to inspect the blade or shift it during operation of the coater.

It has been stated above that the control system controls loosening and fastening of the coating blade 5 in the blade securing device 31. The fastening and also the setting of the blade 5 can be carried out pneumatically, hydraulically, electrically, or mechanically and, if desired, in an alternative embodiment there may be a manually operated coupling release, which may be placed on the ends 33 of the blade holder unit 3, for example.

It will be realized that the invention is not restricted to what is described above but can be varied within the scope of the appended claims. INDUSTRIAL APPLICATION

The invention is intended to be applied for shifting individual coating blades in a device for coating a paper web in a paper or board machine. The coater may be incorporated in a separate coating line or be arranged in the dry end of a paper or board machine.

Claims

CLAIMS:

1. A method of shifting during operation a coating blade (5) held in a blade holder unit (3) in a device for coating a paper or board web (1), wherein the blade holder unit (3) is being moved so as to cause the blade (5) to cease bearing against the web (1).

whereupon the blade (5) is removed from the blade holder unit (3), and that thereupon a new blade (5) is mounted in the blade holder unit (3) and caused to bear against the web (1) by movement of the blade holder unit (3), characterized in that the blade (5) is removed from the blade holder unit (3) by gripping means (8), which thereupon also move the new blade (5) to and place it in the blade holder unit (3).

2. A method according to claim 1, characterized in that the shifting sequence is wholly or partly carried out automatically, and that preferably the blade (5) is removed in its cross direction.

3. A method according to claim 1 or 2, c h a r a c t e r i z e d in that the blade holder unit (3), and preferably also the blade (5) that is to be shifted, are cleaned by washing (9) by means of a wash head (90), which is movable parallel with the blade holder unit and has nozzles (97) for a cleansing fluid.

4. A method according to any one of claims 1-3, characterized in that the

gripping means (8) fetch the blade (5) from a cartridge (10) arranged to hold a plurality of coating blades (5), the gripping means (8) preferably delivering the coating blade (5) removed from the blade holder unit (3) to the cartridge (10).

5. A device for shifting during operation a coating blade (5) held in a blade holder unit (3) in a device for coating a paper or board web (1), characterized in that gripping means (8) are arranged to grip the blade (5), remove it from the blade holder unit (3), and deliver it at a predetermined place (10), and thereupon also to grip the new blade (5), move it to and place it in the blade holder unit (3).

6. A device according to claim 5, characterized in that a shifting unit (7) is arranged to move the gripping means (8) from and toward the blade holder unit (3), in vertical direction as well as in horizontal direction, the shifting unit (7) preferably being driven pneumatically, hydraulically or electrically.

7. A device according to claim 5, char acterized in that it further comprises a washing unit (9), which at a blade shift automatically cleans a blade securing device (31), which washing unit preferably comprises a washing head (90) that is movable along the blade securing device (3) and has nozzles (97) for cleansing fluid.

8. A device according to any one of claims 5-7, characterized in that it

comprises a top frame (6), which carries the shifting unit (7) for moving the gripping means (8), said top frame (6) on its part being carried either by link arms (4), which carry the blade holder unit (3) pivotally, or by a floor that carries the coating device.

9. A device according to claim 7 or 8, characterized in that the washing head (90) is carried by a carriage (91), which can be driven to travel on a track (63) that is parallel with the blade securing device, said track being mounted on said top frame (6), said washing head (90) preferably being movable toward and away from the blade securing device (31).

10. A device according to any one of claims 5-9, characterized in that said

gripping means (8) are arranged to remove said blade (5) in the cross direction.

11. A device according to any one of claims 5-10, characterized in that the entire shift sequence including possible washing is arranged to be carried out automatically, at least substantially.

12. A device according to any one of claims 5—10, characterized in that a

cartridge (10), which has room for at least two coating blades (5) and contains at least one new coating blade, is arranged parallel with the blade holder unit (3) for receiving the blade (5) removed from the blade holder unit (3) and delivering said new coating blade (5) to the gripping means (8), the cartridge (10) preferably being carried by the blade holder unit (3) or located adjacent thereto.