FI92021C - The coating device - Google Patents

Description

92021

a coating

This invention relates to a baling apparatus for baling paper or paperboard or to a machine for spreading paper or paper.

5 In previously known pavers, it has been proposed to use a system located in a baling tank. The brush roll rotates in the opposite direction with respect to the support roll so that the brush roll moves the baling material in the pool toward the brush zone or slot 10 between the brush roll and the support roll. The known proposal includes a baling ring which divides the baling material into two flow paths. The first flow path guides the selection of the web around the shoe of the baling material and the support roll. The second flow path follows the surface of the brush roller. The excess baling material of the first 15 flow paths flows through the overflow pipe and is recirculated.

In the known proposal, the gap between the web passing around the brush roll and the support roll is in the range of 0.2 to 0.5 mm, and the brush roll generally rotates at a speed 10 to 20% lower than the speed of the web 20.

As the swirling roller swings toward the baling material and web, this swirling of the brushing roller generates a wedge pressure that increases as the web passes through the gap between the support roller and the brushing roller. The baling material is divided into the two mentioned above with the first flow path running in the vicinity of the web 1a, while the second flow path follows the brush roll. The point at which the aforementioned flow paths diverge forms a dividing point. Excess baling material is scraped off after the dividing point to preserve the correct Paal-30 system band, i.e. guide baling, on the web.

2 92021 This additional coating material is returned to the coating tank via the aforementioned overflow pipe.

In known proposals, the film thicknesses of the coating-5 applied to the paper web have been of the order of 200-300 μτη and the final film thickness after the excess coating material has been scraped off the web was about 20 μτη. The outer surface of the coating material in the direction of movement after the gap and before the removal of the excess coating material with the blade forms an unstable, free interface due to the negative pressure developing therein. In the transverse direction of the machine, there are thus pressure fluctuations in the width of the roll, which result in the formation of coating patterns on the coating material. These coating patterns include longitudinal lines with wavy lateral cross-sectional shapes.

With regard to the prior art, reference is further made herein to U.S. Patent 3,245,377, which discloses an apparatus for coating paper.

According to the present invention, the aforementioned line-like coating patterns developed by known blade-type coaters degrade the quality of the resulting coated paper webs. Such coated webs contain crack marks in addition to the lines. The above free interface cannot be avoided in coatings using two rolls. More specifically, the aforementioned striped coating pattern is provided by the transverse pressure variations of the coating material-50 lin machine. sa raossa tax in the nip zone. These pressure fluctuations are often due to the air trapped in the nip zone.

In addition, in the known two-roll coater, the pressure is 55 high in the nip zone and the coating material tends to penetrate through the web, resulting in fouling of the support roll. The main object of the present invention is thus to avoid the aforementioned drawbacks of the known proposals and to provide a coater which represents a considerable step forward in the baling technique.

Another object of the present invention is to provide a baling apparatus comprising a support roll and a brush roll and a nip roll substantially cooperating with the support roll 5 to form a nip zone therebetween. The nip zone is positioned forward in the yoke direction 1 i 11e with respect to the gap formed by the brush and support rollers so that the web travels progressively through the gap and the nip belt, so that the baling material is applied to the surface of the web as the web passes through the gap and nip.

It is an object of the present invention to provide a baling device in which the gap between the support roll and the brush roll must be changed.

It is an object of the present invention to provide a baling device in which a baling hall for receiving a baling material forms an opening such that the brush roll is partially inside the basin, so that when the brush roll rotates, the brush roll conveys the baling material in the pool towards the baling material. nip zone.

It is an object of the present invention to provide; A baling device comprising a selector for adjusting the basin towards the support roller.

It is an object of the present invention to provide a baling device in which the nip roll to be rotated is rotatably supported by a shank means so that the nip roll rides on the top of the brush roll.

It is an object of the present invention to provide a baling device in which a nip roll is rotated by means of a drive means such that the nip roll rotates in the same rotating direction as the brush roll to apply a flat layer of baling material to the web as the web passes through the nip belt. chest speed to prevent the accumulation of coating material on it.

It is an object of the present invention to provide a coating device in which the diameter of the nip roll is smaller than the diameter of the brush roll and the support roll so that the nip pressure applied to the nip roll and the support roll

Other objects and advantages of the present invention will become apparent to those skilled in the art upon review of the following detailed description taken in conjunction with the accompanying drawings.

The invention is mainly characterized by what is stated in the appended claims.

The present invention relates to a coating apparatus and method for applying a coating material to the surface of a paper web. The apparatus comprises a support roll and a brush roll in co-operation with the support roll to form a gap. being positioned with respect to the gap 25 in the forward direction of movement. The roll is a nip roll which passes over the brush roll, so that the coating material is applied to the surface of the web as the web passes through the gap and the nip zone.

• In a more specific embodiment of the present invention, the coating device also includes a body that rotatably supports the support roller. The lubrication roller is movable relative to the support roller so that the gap between the support roller and the brush roller must be changed.

The coating apparatus also includes a coating tank for receiving coating material. The basin forms an opening so that the brushing roller is rotatably positioned inside the basin, so that when the brushing roller is rotated, the brushing roller conveys the coating material in the basin from the basin 5 towards the gap and the nip zone.

The baling device also includes a transfer means positioned to move the body and the pool to move the pool towards the support roll. More specifically, the transfer medium is an air cushion.

10 The baling device further comprises a color selector having a head near it and a head remote from the fulcrum. The head near the arm member is pivotally attached to the frame, and the head at the distance from the support point rotatably supports the nip roll so that the nip roll rides on the top of the sive-15 lytel.

The baling device further includes a drive means for rotating the nip roll with respect to the selected color such that the nip roll rotates in the same rotational direction as the brush roll to apply a flat baling material to the web as the web passes through the nip zone. The nip roll is rotated at such a rotational speed that the agglomeration of the bale system material is prevented.

The diameter of the nip roll is smaller than the diameter of the brush roll and the support roll so that as the web passes through the nip zone, the nip pressure applied between the nip roll and the support roll is insufficient to cause penetration of the web and the resulting support roll 1 aging.

The method comprises the steps of rotating the brush roll in a pool containing the coating material. The roller roll conveys the baling material towards the gap formed between the brush roller and the support roller. The nip roll is rotated in the same direction of rotation as the brush roll so that the nip roll rests on the brush roll so that a uniform layer of coating material is applied to the web surface 1 between the rotating nip space and the cooperating support roll.

As will be apparent to those skilled in the art, many modifications and variations can be made to the basic principle of the present invention without departing from the spirit and scope of the present invention as defined in the appended claims. Although an electric motor is shown in the preferred embodiment with respect to the color selection of the nip roll rotation, it will be apparent to those skilled in the art that many means may be used to achieve the desired nip roll rotation. In addition, although the present invention has been specifically described with reference to a baler for baling a baling material on paper, the basic principle of the present invention can also be applied to the application of an ink layer to a baling cylinder or the like.

Fig. 1 is a partially sectioned side view showing a known blade type baling device; Fig. 2 is an enlarged side view of the device of Fig. 1 showing a nip roll, a gap between the brush and support roll and a nip zone; Fig. 3 is an enlarged sectional view taken along line 3 of Fig. 1; -3, 25 Fig. 4 is a side view of the device i according to the present invention, Fig. 5 is a view taken in the direction 5-5 of Fig. 4, Fig. 6 is a sectional view taken along line 6-6 of Fig. 4, Fig. 7 is a schematic view showing Figs. 6:30, a nip roll and a support roll and a wedge pressure distribution of the present invention as shown in Fig. 6:30, and Fig. 8 is a sectional view taken along line 8-8 of Fig. 7.

Fig. 1 is a side view of a known baling device including a rotatable support roll 1 cooperating with a rotatable brush roll 2, the brush roll 2 swinging in the opposite direction of rotation with respect to the support roll 1. The brushing roll 2 is inside the baling basin 3 so that when the brushing roller 2 swells inside the basin 3, the brushing roller 2 conveys the baling material a 5 in the basin 3 towards the gap G formed between the support 10 and the brushing roll 2. The nip zone NS is located in the yoke direction 1 i with respect to the gap G, with the nip zone advancing between the shoe S and the support roll 1. The shoe S forms a dividing point P which divides the baling material 5 into two flow paths FP1 and FP2.

The flow path FP1 runs through the nip zone NS so that the baling material 5 is pressed between the shoe S and the web 6. The blade 4 scrapes the excess baling material from the surface of the web 6 so that the excess baling material is fed through the pipe 7 and circulated back through the pipe 20 8 to the baling basin 3.

The second flow path FP2 follows the brush roll 2 so that the baling material 5 is circulated through the baling basin 3. The baling material overflowing from the baling basin 3 1 i in the yoke direction before the gap is also circulated back through the pipe 7 25 to the baling basin 3.

Fig. 2 is an explanatory drawing showing the wedge pressure distribution of the known device of Fig. 1, indicated by the line WPD.

Fig. 3 is a sectional view taken along line 3-3 of Fig. 1, showing the application of the baling material 5 to the web 6 and the resulting drift 44 of the support roll 11.

τ—: 8 92021

Figures 4-8 generally show a baling device according to the present invention, indicated by reference numeral 10, for applying a baling material to the surface of a paper web. The baling device 10 includes a support roll 12 and a brush roll 14 14 which cooperates with the support roll 12 to form a gap G1 between them along the passage of the web 16. The support roller 12 and the brush roller 14 rotate in opposite directions at predetermined speeds, and the nip roller 18 cooperates movably with the support roller 12 to form a nip cluster NS1 between them, as shown in particular in Fig. 7. The nip zone NS1 is located forward in relation to the slot G1 so that the web 16 passes progressively through the slot G1 and the nip block NS1, so that the coating material 20 is applied to the surface of the web 16 as the web 16 passes through the gap G1 and the nip block NS1.

More specifically, the baling device 10 includes a frame 22 that rotatably supports a support roller 12.

The lubrication roller 14 can be moved relative to the support roller 12 so that the gap G1 between the support roller 12 and the brush roller 14 must be changed.

The device 10 includes a baling tank 24 for receiving baling material 20. The basin 24 has an opening 26 such that the brushing roller 14 is rotated against the basin 24 so that when the brushing roller 14 is rotated, as indicated by those 25, the brushing roller 14 conveys the baling material 20 in the basin 24 from the basin 24 to the slot G1. and per nip piv zone NS1.

The device 10 further includes a transfer means, generally indicated at 28, located for moving the body 22 and the basin 30 24 toward the support roll 12. Most preferably, the airbag 28 is an air cushion 30.

9 92021

The coating device 10 includes a shank assembly indicated generally at 32, wherein the proximal end 34 and the remote end 36 are provided. The proximal end 34 is pivotally attached at 38 to the body 22, while the 5 main end position 36 rotatably supports the nip roll. 18, as shown in Fig. 6, with the nip roll 18 riding on the brush roll 14.

As shown in particular in Figure 4, the drive means indicated generally by reference numeral 40 rotates the nip roll 18 10 relative to the arm means 32 so that the nip roll 18 rotates in the same rotational direction as the brush roll 14 to apply a layer 20 of flat baling material 20 to the web 16 as the web 16 passes through 1 lapi. The nip roll 18 is rotated at such a rotational speed that the coagulation of the baling material is prevented.

As can be seen in particular from Figure 5, the diameter of the nip roll 18 is smaller than the diameter of the brush roll 14 and the support roll 12 so that as the web 16 passes through the nip zone NS1 the nip pressure applied between the nip roll 18 and the support roll 12 is insufficient to infiltrate the web 16. and the resulting problem of contamination of the support roller.

Fig. 7 is a cross-sectional view of a portion of a baling device NS1 surrounding the nip-25 of the baling device according to the present invention, in which the support roll 12, the brush roll 14, the baling roll 24, the baling material i 20 and the web 16 are similar to those shown in Fig. 1. . The nip roll 18 is positioned near the nip zone NS1 with respect to the slot G1 in the forward direction 30. In addition, the nip roll 18 is rotated at a suitable speed to prevent the baling material from accumulating thereon. As shown in Fig. 6, the nip roll 18 is supported on the arms 46 and 48 projecting from the body 22, so that the nip roll 18 can be seen between the support roll 12 and the brush roll 14. In addition, the nip roll 18 can be driven by bearings 50 and 52 by means of a low-power motor 40. The jar arrangement described is shown by way of example. It is clear to a person skilled in the art that the nip roll can be used with different options. As shown in Figure 4, the arms 48 and 46 can be moved in the direction of arrow 54 osoittamal1a manner.

In the known arrangement shown in Fig. 1, the causes of the coating-liquid film surface imbalance at the dividing point P at point 10 are relatively large in the radial direction. This arrangement causes a pattern to form on the web instead of a uniform coating. In the arrangement of the present invention, the striped baling pattern according to the prior art is prevented by reducing the distance 15 between the support roll and the shoe by using a small diameter nip roll 18 placed near the liquid film dividing point.

A further advantage of the present invention is that the absolute value of the nip pressure or wedge pressure distribution shown by the line NPD1 is reduced below the value of known proposals by reducing the diameter of the nip roll 18 to a sufficient viscosity of the high viscosity baling material 20. aging of the existing support 12 1. The distance between the nip roll 18 and the support roll 12 can be adjusted by a guide system 25 (not shown) well known in the art. The distance mentioned above is set to the determined value by means of a sensor device, generally indicated by reference numeral 56, attached to the support. This sensor device 56 cooperates with the baling basin 24 to allow vertical movement of the baling basin 24 30 by using an air cushion 30 mounted on a bracket 58 mounted on the frame 22, as shown in Fig. 4.

In operation of the invention shown in Figures 4-8, the baling roll 14 raises the baling material 20 so that the baling material i 20 comes into contact with the paper web 16 at a point close to the centerline of the support roll 12 and the coating roll 14. The nip pressure begins to build up at the contact-5 point 62 and maintains a small absolute value in the region of the nip roll 18. In addition, the width of the nip in the region NSI is smaller than in the known proposals due to the small diameter of the nip roll 18. The absolute value of the nip pressure can thus be reduced while keeping the type of baling material the same. This means that the invention provides an efficient means of handling a baling material which tends to contaminate the support roll 12 by penetrating the web 16. The baling materials 20 can be applied to the webs in such a way that the free volume is kept as small as possible, so that it is possible to produce a web with excellent printing properties. In addition, the rain-like causes of the roll of the surface of the baling liquid film at point P are avoided or at least reduced, so that the streaking or baling pattern 20 can be made as small as possible.

The present invention provides a baling device, in which the problems of streaking and limitation of the prior art shown in Fig. 3 are avoided. In addition, the wedge pressure can be controlled by a nip roll 18, which can be set to an arbitrary position between the support roll 12 and the squeegee roll 14. The quality of the baled paper webs can thus be improved by using the right nip conditions depending on the type of baling material and the webs used.

Claims (11)

92021 ----------- 'τ—: 12 A coating device (10) for applying a coating material (20) to the surface of a paper web (16), the coating device (10) comprising: a support roll (12), a brush roll (14) cooperating with the support roll (12) to form a gap (GI) between the passage of the web (16) as said support and brush rollers (12, 14) rotate in opposite directions at predetermined speeds, and a roll (18) movably cooperating with the support roll (12) to form a nip zone (NSI) for them; NSI) is positioned forward in the direction of movement relative to the slit (GI), characterized in that the roll (18) is a nip roll (18) which rides on the brush roll (14), so that the coating material is applied to the surface of the web (16). ) as it passes through the gap (GI) and the nip zone (NSI). Coating device according to Claim 1, characterized in that the nip roll (18) is rotatable in the same direction of rotation as the brush roll (14). . Coating device according to claim 1, characterized in that the device further comprises a body (22), which body (22) rotatably supports a support roller (12). Coating device according to Claim 1, characterized in that the brush roll (14) is displaceable relative to the support roll (12) so that the gap (GI) between the support roll (12) and the brush roll (14) is variable. Coating device according to claim 1, characterized in that it has a coating basin (24) for receiving the coating material inside it, the basin (24) forming an opening (26) such that the coating roller (14) is located partially inside the basin, so that when the brush roll (14) is rotated, the brush roll (14) conveys the coating material (20) inside the basin (24) from the basin (24) towards the gap (GI) and the nip zone (NSI). Coating device according to Claim 5, characterized in that a transfer means (28) is arranged between the body (22) and the basin (24) for moving the basin (24) towards the support roll (12). Coating device according to Claim 6, characterized in that the transfer means (28) is an air cushion (30). Coating device according to claim 1, characterized in that it further comprises a shank means (32) having an proximal end (34) and a distal end (36), the proximal end (34) being pivotally attached to the body. (22), the distal head (36) rotatably supporting the nip roll (18) such that the nip roll (18) rides on the brush roll (14). Coating device according to claim 1, characterized in that the diameter of the nip roll (18) is smaller than the diameter of the brush roll (14) and the support roll (12) so that as the web (16) passes through the nip roll (18) and the support roll The nip pressure applied between (12) is insufficient to cause the web (16) to penetrate and result in fouling of the support roll (12). A method of applying a coating material to the surface of a paper web, the method comprising the steps of: 14) and towards the gap (GI) formed by the support roller (12) cooperating therewith, the support and brush rollers (12, 14) rotating at opposite speeds, movably arranging the roller (18) cooperating with the support roller (12) in their respective directions. to form a nip zone (NSI) forward in the direction of movement of the gap (GI) so that the web (16) extends through the gap (GI) and through the nip zone (NSI), characterized in that the roll (18) is arranged to nip which rides on the brush roller (14) so that a uniform layer of coating material (20) is applied to the surface of the paper web (16). as the ina (16) passes through the nip zone (NSI). A method according to claim 10, characterized in that the brush roll (14) is moved relative to the support roll (12) such that the nip roll (18) riding on the brush roll (14) forms a nip roll (18) of the variable nip zone (NSI) and a cooperating support roll (12). ).