CN105603822A - Sealing blade - Google Patents

Abstract

The invention relates to a sealing blade, which includes opposite elongated edges (30, 31) and between them a flat (32) and which is adaptable to a blade holder (17) arranged in a coating applicator (25) of a coating device (21) and into contact with a moving surface (11'). A contact surface (33), which may be arranged against the moving surface and which is 5 - 15% of the width (W) of the sealing blade, is adapted in the sealing blade (10).

Description

Sealing blade

technical field

The present application relates to a sealing blade, the sealing blade includes opposite elongated edges and a flat part between the opposite elongated edges, the sealing blade is suitable for a blade frame, the blade frame is arranged in a coating machine of a coating device in and in contact with a moving surface.

Background technique

Coating or surface sizing of paper or board can be carried out, for example, using film transfer coaters. Therein, the web to be treated travels through a nip located between two rolls. The coating mixture or size is spread using a special coater on the surface of one roll or two rolls and is transferred from this surface to the surface of the web to be treated in the nip between the rolls. The thickness and contour of the sizing agent layer on the surface of the roller can be adjusted, for example, by means of a doctor blade or a rotating measuring rod.

The coating machine may comprise an application chamber which is bounded in the direction of rotation of the roller by the doctor element and on the other hand by the front wall. In transverse direction, the application chamber is limited by side seals. The coating mixture or surface size is supplied to the application chamber, for example through channels located in the beams of the coater. The coating mixture is fed into the application chamber with such great velocity and pressure that a return flow is created in the gap between the front wall and the application roller, in other words, the flow of coating mixture or sizing agent flows along with the application chamber. The direction of rotation of the rollers is opposite to that produced. The purpose of the return flow is to prevent air on the surface of the applicator roll from penetrating into the applicator chamber. If air is able to enter the application chamber, uncoated spots can result in the web.

It is known that sealing blades can be used to close off the front wall of the application chamber. The sealing blade can be pressed against the application roller so that no air can escape from between the doctor blade and the application roller into the application chamber. There is no actual return flow between the sealing blade and the application roller, but some coating mixture is directed from the application chamber to the front of the blade through flow openings (flow openings) in the sealing blade. In this case, a lubricant pool is formed in front of the sealing blade, which lubricant pool prevents friction occurring between the sealing blade and the application roller from damaging the roller of the sealing blade. If, for example, the pressure of the application chamber increases due to an oversupply of coating mixture, the force with which the sealing blade is pressed against the application roller increases, whereby the sealing blade wears faster and can damage the application roller or at least wear the application roll.

However, a disadvantage related to prior art sealing blades is that the edge of the blade placed against the applicator roller becomes sharp with use of the blade. This causes occupational safety problems in the maintenance of coating machines. Sharp sealing scrapers are a danger for maintenance personnel, for example when replacing the sealing scraper, the measuring scraper or the cradle of the measuring scraper. For the replacement of only the measuring bar and its cradle, which in some cases needs to be performed more frequently than that of the sealing blade, it is often not customary to remove the sealing blade from the coater, since it is more troublesome to perform. The difficulty with removing the sealing blade is that the sealing blade can be firmly stuck to its blade holder and therefore will need to be cleaned to facilitate removal. Sealing blades that have become sharp and difficult to remove can cause cuts to employees and can also damage the surface of the applicator roll.

Attempts have been made in many different ways to solve the problems associated with sealing blades becoming sharpened, but with little success. Since the blade holder of the sealing blade is fastened to the beam in a fixed manner, it is difficult to change the position of the blade holder. The sealing blade can also be raised in the doctor blade holder, but this does not always give the desired result. Attempts to increase lubrication to reduce friction between the seal blade and applicator roller could be made by varying the supply pressure, but this is limited by seals that do not seal well enough and by fouling problems. Furthermore, the transition to thinner sealing blades and higher chamber pressures is undesirable due to reasons such as increased leakage and splashing.

A prior art sealing blade is mentioned in FI (Finland) Patent No. 103058. The sealing blade known from this patent is a flat item. The two planar surfaces of the blade are therefore substantially similar planar surfaces, in other words the front and rear edges of the blade are in the same plane.

Contents of the invention

The object of the invention is to achieve a sealing doctor blade whose edges become less sharp. The features of the sealing blade according to the invention are presented in a sealing blade comprising opposing elongated edges and a flat portion between said opposing elongated edges, and said sealing blade is adapted to a blade holder, so The doctor blade holder is arranged in the coater of the coating device and comes into contact with the moving surface, characterized in that a contact surface is adapted in the sealing doctor blade, which contact surface can be arranged against the moving surface , and the contact surface is 5%-15% of the width of the sealing blade.

In the present invention, a contact surface which can be arranged against the moving surface and has a width of 5%-15% of the sealing blade is suitable in the sealing blade. As a result of the contact surface having been adapted in advance in the sealing blade, the angle between the sealing blade and the moving surface is reduced, the contact area of the sealing blade with the moving surface is increased and the wear of the sealing blade is reduced. In this way, the flat surface of the sealing blade is also reliably in contact with the moving surface, the sharpening of the elongated edges of the sealing blade is reduced, and occupational safety in connection with maintenance of the coating device is enhanced.

According to one embodiment, the flow opening may be included in the flat part of the sealing blade. In this case, the majority of the contact surface is adapted between the elongated edge and the flow opening. This ensures optimal functioning of the flow opening in all situations and that the flow opening does not sit against a moving surface.

It is possible that the flat portion of the sealing blade is divided into two or more regions and the contact surface is formed in at least one region. Segmentation can be done in different ways. Examples include folds or roundings made in the flat portion of the sealing blade. The present invention can also achieve some other advantages, such as longer service life of sealing blades, longer replacement intervals of rolls, less variation of paper and board quality and higher output of paper and board when the sealing blades do not need to be replaced prematurely. high. Other additional advantages to be achieved by the present invention are disclosed in the description of the present invention.

Description of drawings

The present invention is not limited to the embodiment given below, the present invention is described in more detail below with reference to accompanying drawing, in accompanying drawing:

Figure 1 shows a schematic example of a coating device viewed from the side,

Figure 2 shows an example of a coater viewed from the side,

Figure 3 shows an example of a sealing blade viewed axially from the top, from one end of the sealing blade, and

Figures 4a-4c show a rough level schematic view of various embodiments of the sealing blade and how it is positioned against the applicator roller, viewed from the side.

detailed description

FIG. 1 generally shows an example of a coating device 21 viewed from the side. In this case, the device 21 comprises two rotating applicator rolls 22, 11 adapted for nip contact and the paper or board to be treated (in other words to be surface sized or coated) The web 24 is adapted to travel between these two rotating applicator rolls. The direction of travel of the web 24 is indicated by arrows, and the direction of travel of the rolls 22, 11 is also indicated by arrows. A treatment substance of the web 24, such as a coating mixture or a surface size, is spread by means of a coater 25 on the surfaces 22', 11' of the application rolls 22, 11. The treatment substance layer is leveled and its thickness is adjusted by means of a doctor element such as a doctor blade or a rotating measuring doctor bar (reference number 15 in FIG. 2 ). The scraped layer of treatment substance is transferred from the application rolls 22 , 11 to both sides of the web 24 being treated in the nip between the rolls 22 , 11 . If only one side of the web 24 is being treated, the treatment substance may be spread over only one applicator roll (eg, applicator roll 11 ).

FIG. 2 shows an example of a coater 25 viewed from the side. In this case, the coater 25 is constructed to be placed on the beam 12, and the application chamber 20 against the application roller 11 is formed by a space in the beam 12 which is divided in the direction of rotation of the application roller 11. The sealing scraper 10 which comes first (ie on the inlet side) is delimited by the measuring scraper 15 on the outlet side (ie behind in the direction of rotation). The sealing scraper 10 is fastened to the beam 12 by means of a scraper holder 17 and the measuring scraper 15 is fastened by means of a scraper holder 14 .

The sealing blade 10 presses against the surface 11' A measuring bar 15 is placed at a distance from the sealing blade 10 , which is pressed against the applicator roll 11 , but which is hydrodynamically suspended at a distance from the roll 11 by a film transferred to the rotating roll 11 . at a certain distance from the surface 11'. The thickness of the film transferred to the surface 11' of the roller 11 is adjusted by changing the load of the measuring blade 15. The distance between the sealing blade 10 and the measuring blade 15 forms the application distance, so that the application chamber 20 is bounded by the beam 12 , the sealing blade 10 , the measuring rod 15 and the application roller 11 . The ends of the application chamber 20 are sealed according to the present embodiment by means of a flexible seal 19 which limits the width of the area to be coated. The coating is supplied to the application chamber 20 from the main pipe 13 located within the beam 12 through nozzles 18 and across the entire width of the coater 25 .

FIG. 3 shows an example of a sealing blade 10 , viewed axially from the top, from one end of the sealing blade, which may correspond to the one installed in the coating machine 25 in FIG. 2 . The sealing blade 10 comprises opposing elongated edges 30, 31 and a flat portion 32 between the two elongated edges. The flat portion 32 has opposite sides forming flat surfaces 32a and 32b. The flat surface 32 a of the flat portion 32 is on the roller 11 side, and the flat surface 32 b is on the application chamber 20 side. Of these flat surfaces, FIG. 3 shows a flat surface 32 b on one side of the application chamber 20 .

The sealing blade 10 may be adapted to be arranged on a blade holder 17 in the coater 25 of the coating device 21 and in contact with the moving surface 11' so that it can be replaced. To this end, the sealing blade 10 comprises a fastening area 37 adapted to be on the side of the first elongated edge (rear edge) 31 from which the sealing blade 10 is adapted to be fastened to the blade holder 17 . In the fastening area 37 there may be, for example, die-cut fasteners which ensure fastening of the doctor blade 10 to the blade holder 17 . Opposite this first edge 31 coming to the elongated knife holder 17, a second elongated edge (front edge) 30 comprises a pointed point 38 adapted to abut against the moving surface 11'.

Adapted in the sealing blade 10 is a contact surface 33 which may be arranged against the moving surface 11'. Some examples of contact surfaces 33 are presented in Figures 2 and 4a-4c. The contact surface 33 is on the flat surface 32a of the sealing blade 10 on the side of the roller 11 (in other words, on the side different from that of the application chamber 20). (The width of) the contact surface 33 may be 5%-15% of the width W of the sealing blade 10 . In this regard, the width W of the sealing blade refers to the distance between the elongated edges 30 , 31 of the sealing blade 10 measured along the flat portion 32 . Correspondingly, the length L of the sealing blade 10 refers to the length of the sealing blade 10 in the transverse direction of the machine. The length L of the sealing blade 10 can be several meters up to 10 meters. The directions W and L are perpendicular to each other. It must be noted that the proportions of the sealing blade 10 and its parts in the figures are not necessarily the actual proportions. As a result of the contact surface 33 being arranged in the sealing blade 10 as early as during its manufacture, when the sealing blade 10 is installed in the blade holder 17, the sealing blade is at a suitable angle with respect to the roller 11 and thus for example The lubrication of the tip 38 of the sealing blade 10 becomes adequate and even the tip 38 becomes less sharp because a part of the flat surface 32a abuts against the moving surface 11'.

By arranging the contact surface 33 in the sealing blade 10 , the sealing blade can be made more reliable over a larger area and especially on its flat part 32 than merely by means of a connection on the elongated edge 30 of the sealing blade. contact with the moving surface 11'. Furthermore, the contact surface 33 is already in the sealing blade 10 before the sealing blade is installed in the blade holder 17 and is not formed only when the blade 10 is loaded against the moving surface 11'. In other words, it can also be said that the initial tension has been removed from the doctor blade 10 when the doctor blade is mounted in its doctor blade holder 17 . This makes the contact between the flat portion 32 of the scraper 10 and the moving surface 11' very reliable, while the sharpening of the tip 38 of the scraper 10 is reduced.

According to one embodiment, the flow openings 34 , 34 . 1 - 34 . 3 may be adapted in the flat portion 32 of the sealing blade 10 . Some examples of the location of these flow openings have been presented in FIGS. 4 a - 4c , where the flow openings are generally depicted by double-headed arrows passing through the flat 32 of the scraper 10 . A large part of the contact surface 33 can be adapted between the elongated edge 30 and the flow opening 34 , 34 . 1 - 34 . 3 of the doctor blade 10 . The contact surface 33 and the flow openings 34, 34.1-34.3 are adapted in the sealing blade 10 such that when in contact with the moving surface 11' the flow openings 34, 34.1-34.3 adapted in the sealing blade 10 are at least partly in contact with the moving surface 11' apart. In this case the moving surface 11' does not block the flow openings 34, 34.1-34.3. This also ensures that the flow openings 34 , 34 . 1 - 34 . 3 are functioning in any case, in other words, air is prevented from entering the chamber 20 , the lubrication of the sealing blade 10 is ensured, and excess pressure is removed from the chamber 20 . As a result of the invention, it is even possible to increase the impact achieved by the flow openings 34, 34.1-34.3. The position of the flow openings 34, 34.1-34.3 on the flat part 32 of the scraper 10 can be optimized e.g. close to the standard contact surface 33 and thus e.g. the lubrication between the scraper 10 and the moving surface 11' can be enhanced.

According to one embodiment, for example, the contact surface 33 may be arranged in the sealing blade 10 such that the flat portion 32 of the sealing blade 10 is divided into two or more regions 35.1-35.3, wherein the contact surface 33 is formed in at least one region 35.1 , in other words, formed on one side of the flat portion 32 . In Figures 4a and 4b the sealing blade 10 has been divided into two regions 35.1, 35.3, the contact surface 33 being in the region 35.1. In Fig. 4a the contact surface 33 is in the planar region 35.1, whereas in Fig. 4b the contact surface 33 is in the curved region 35.1. Correspondingly, in Fig. 4c, the sealing blade 10 has been divided into three regions 35.1-35.3, and the contact surface 33 is again in region 35.1, which here is also a planar region.

According to the embodiment shown in Figures 4a-4c, the regions 35.1-35.3 can be formed in some different ways. According to a first embodiment, the flat portion 32 of the sealing blade 10 is divided into two or more regions 35.1-35.3 by means of one or more folds 36.1, 36.2. In Figures 4a and 4b the sealing blade 10 has one fold 36.1, while in Figure 4c the sealing blade 10 has two folds 36.1, 36.2. The folds 36.1, 36.2 can be beveled (oblique) sharp folds or also rounded folds. With two folds 36.1, 36.2, the angle of the folds need not be so great. The flat part 32 of the sealing blade 10 can also be divided into two or more regions 35.1, 35.3 by means of one or more roundings 36.3. This is eg the case in Fig. 4b. The folding 36.1 , 36.2 and/or rounding 36.3, more generally, the removal of the initial tension of the sealing blade 10 can eg be carried out at the final stage of manufacture of the sealing blade 10 .

FIG. 4 a shows three different possibilities for arranging the flow openings 34 . 1 - 34 . 3 in the sealing blade 10 . These flow openings can eg be in the same region 35.1 with the contact surface 33, in which case the flow openings are between the fold 36.1 and the contact surface 33. These flow openings may also be in the same area 35 . 3 in which the sealing blade 10 is fastened to the blade holder 17 . Furthermore, these flow openings can also be precisely at the folds 36.1. In the embodiment of Fig. 4b the flow opening 34.3 is in the area 35.3, while in Fig. 4c the flow opening 34.1 is in the area 35.2.

The distance D of the top edge of the flow opening 34 (in other words, the edge closest to the tip 38 of the blade 10 ) from the elongated edge 30 of the sealing blade 10 (which edge 30 is equipped with the tip 38 ) may be, for example, 15mm-50mm. The sealing blade 10 can be, for example, spring steel type 1,4301, and its material thickness can be, for example, 0.254mm-0.381mm, and the overall width W can be, for example, 100mm-130mm.

As already mentioned above, the sealing blade 10 according to the invention is no longer a flat object as known from the prior art. Alternatively, the leading edge 30 of the sealing blade deviates from the planar surface. This deviation can be done, for example, by means of one or more corner folds in the direction of the length L of the blade 10 . The fold may be located 5%-15% of the distance in the direction of the width W of the spatula 10 from the tip 38 of the spatula 10 , which is the edge 30 opposite the edge 31 on the spatula 17 side. Another alternative, presented eg in Fig. 4b, is to round off the tip of the doctor blade 10 in the region 33 in question, so as to be curved in the same direction as the curvature of the roll surface 11'.

It should be understood that the foregoing description and the associated drawings are only intended to illustrate the present invention. Therefore, the present invention is not limited to the above-mentioned embodiments or the embodiments defined by the claims, and various modifications and adjustments of the present invention will be obvious to those skilled in the art. within the scope of the inventive concept defined by the claims.

Claims (9)

1. a seal blades, sealing scraper comprises relative microscler edge (30,31) and instituteState the par (32) between relative microscler edge, and described seal blades is adapted to doctor blade holder(17), described doctor blade holder is arranged in the coating machine (25) of apparatus for coating (21), and and mobile watchFace (11 ') contacts, and it is characterized in that, a contact surface is suitable in described seal blades (10)In, this contact surface (33) can be arranged to against described translational surface (11 '), and described contactSurface is the 5%-15% of the width (W) of described seal blades (10).

2. seal blades according to claim 1, is characterized in that, multiple flow openingsIt is upper that (34,34.1-34.3) are suitable for par (32) in described seal blades, described contact surface (33)Major part be suitable between described microscler edge (30) and described flow openings (34,34.1-34.3).

3. seal blades according to claim 1 and 2, is characterized in that, flow openings (34,34.1-34.3) be suitable on the par (32) in described seal blades, described contact surface (33) is suitableIn in described seal blades (10), make, in the time contacting with described translational surface (11 '), to be suitable forDescribed flow openings in described seal blades (10) (34,34.1-34.3) at least in part with instituteState translational surface (11 ') separately.

4. according to the seal blades described in claim 1-3 any one, it is characterized in that described sealingThe par (32) of scraper (10) is divided into two or more regions (35.1-35.3), described contactSurface (33) is formed at least one region (35.1) in described two or more region.

5. according to the seal blades described in claim 1-4 any one, it is characterized in that described sealingThe par (32) of scraper (10) is divided into two by one or more folding (36.1,36.2)Or multiple regions (35.1-35.3).

6. according to the seal blades described in claim 1-5 any one, it is characterized in that described sealingThe par (32) of scraper (10) is divided into two or more by one or more roundings (36.3)Region (35.1,35.3).

7. according to the seal blades described in claim 2-6 any one, it is characterized in that described flowingThe top edge of opening (34) is to the distance (D) at the microscler edge (30) of described seal blades (10)15mm-50mm.

8. according to the seal blades described in claim 1-7 any one, it is characterized in that described sealingScraper (10) comprising:

-fastening area (37), is suitable in first that side of microscler edge (31), described seal blades (10)Be suitable for being secured to described doctor blade holder (17) from described fastening area (37),

The-the second microscler edge (30), relative with described the first microscler edge (31),

-plane surface (32a, 32b), is positioned at the relative both sides of described seal blades (10), describedBetween microscler edge (30,31), described contact surface (33) is suitable for the side at described plane surface.

9. seal blades according to claim 8, is characterized in that, one is suitable for moving against describedThe tip (38) on moving surface (11 ') is suitable for the microscler edge (30) in described seal blades (10)On.