JPH0318109B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a plastic film after coating,
This hot air nozzle blows hot air onto a web such as paper or aluminum foil, especially a thin web that requires low tension when passing through the drying chamber, and heats and dries the web while floating the web in the drying chamber.

Figure 1 shows an outline of a typical floating dryer, in which a web is placed in a drying chamber A.
A large number of nozzles 2 are arranged at regular intervals along the web width direction, alternating vertically (in some cases, vertically facing each other) across the web, and the hot air ejected from these nozzles 2 is The hot air is blown onto the web 1 to float the web 1 while drying it with hot air.

As this type of floating drying nozzle 2, as illustrated in FIG. Hot air is blown toward the web 1, and a central zone 2 is surrounded by two jets of hot air from both slits 27 between the web 1 and the upper wall 14 of the nozzle box 3 facing thereto.
A type of apparatus is known in which a positive static pressure is generated at 8 to dry the web 1 while floating and supporting it. For example, Japanese Patent Publication No. 44-11451, No. 45-
This can be found in JP-A No. 36953, JP-A No. 53-551, JP-A No. 54-38525, and JP-A-57-142473.

The present invention is directed to a hot air nozzle of this type, in which improvements have been made particularly in the shape of the opening of the hot air blowing slit 27.

In other words, in order to increase processing efficiency by feeding the web at high speed with this type of nozzle, the distance between the facing surfaces of the nozzle and the web is extremely small, in fact it is 10 mm.
Below, it is generally set to 5 to 7 mm in some cases. However, in the case of wide webs that require low tension,
Originally, the frictional resistance with the air is extremely small and the thickness is thin, so even when subjected to a slight external force, the web tends to meander, especially flapping, and it is impossible to completely suppress this flapping. .
For example, if there is not only a structural defect in the nozzle, but also a slight imbalance in the tension in the width direction of the web during high-speed running, the web will flap significantly. This is because there are a variety of factors that cause webs to flutter.

The problem is how to eliminate the problem of the web flapping and coming into contact with the nozzle side.
If the web comes into contact with a part of the nozzle, a mark will be placed on the web and the product will be rejected, and in the worst case, the web will be damaged and cause serious trouble.

In order to solve this important problem, let us consider once again the conventional nozzle structure. In FIG. 9, the static pressure zone 28 is extremely significant for maintaining the web 1 at a predetermined flying level. The hot air ejected from the pair of slits 27, 27 applies positive static pressure to the zone 28 while lateral to the outer side of the zone 28 (in the direction of arrow a in FIG. 9).
The airflow flowing away is mainly used to dry the web 1. However, the flow of hot air in the direction of arrow a is restricted by the web 1, which is flapping and is traveling at high speed. Therefore, web 1
It has been learned that if there is flapping in the web 1, turbulence occurs in the flow of this hot air, and the flapping of the web 1 cannot be easily calmed down, but rather tends to increase the flapping. Considering that the distance between the opposing surfaces of the nozzle 2 and the web 1 is actually 10 mm or less, it is preferable to restrict the flow of hot air in the direction of the arrow a by a fixed wall surface on the nozzle side.

Therefore, as shown in FIG. 9, guide plates 19, 19 including guide walls 20, 20 are integrally provided on the lateral outer sides of the lateral side walls 16, 16 connected to the top wall 14 of the nozzle box 3, and When forming the slit 27 between each guide wall 20, a lip (not shown) extending outward from the upper end of the guide wall 20 is bent horizontally to prevent flapping occurring in the web 1. To suppress the
It is known in the publication No. However, since the lip in these conventional examples is formed horizontally parallel to the web, when the hot air leaves the web at the extending end of the lip, negative static pressure is applied to the extending end. This causes the web 1 to come into contact with the extended end of the lip and be susceptible to damage. Furthermore, when a new web is passed over the nozzle at the beginning of operation, the web is likely to get caught on the extending end of the lip and be damaged. Such damage to the web can lead to serious problems such as the inability to drive.

Furthermore, in the conventional nozzle structure, nozzle box 3
It is difficult to form a pair of slits 27 on the top surface of the box 3 at appropriate intervals in the longitudinal direction of the box 3, and the manufacturing accuracy is insufficient. The distribution and direction of the wind were uneven, which increased the flapping of the web. In particular, with this type of drying nozzle, the spacing between the slits 27 should be finely adjusted in the longitudinal direction at the time of trial operation, etc., but in the past, the guide wall 20 was formed integrally with the nozzle box 3. Because of this, slit 2
There was also a problem in that it was difficult to adjust the spacing of item 7 on site.

The present invention was proposed in order to eliminate such conventional problems.

The object of the present invention is to provide an outward lip on the nozzle side that allows the hot air blown from the slit to flow smoothly laterally and outwardly, and to prevent the web from coming into contact with the lip while suppressing flapping that occurs in the web. To obtain a floating drying nozzle that can reliably control the drying process.

Another object of the present invention is to obtain a floating drying nozzle that can ensure manufacturing accuracy of the entire nozzle including the slit and facilitate manufacturing.

Still another object of the present invention is to provide a floating drying nozzle that allows delicate and important spacing adjustments in the longitudinal direction of the slits to be easily made on site during test runs or repairs.

In order to achieve the above object, in the present invention, in a floating drying nozzle having the above-mentioned basic configuration, lateral side walls connected to the upper wall are provided on both sides of the upper wall facing the web of the nozzle box in the web feeding direction. having a guide plate attached to each of the opposing long wall plates of the nozzle box on the lateral outer side of the lateral side wall;
Each guide plate includes a guide wall forming a series of slits between the guide plate and the horizontal side wall, an outward lip bent diagonally downward from the upper end of the guide wall, and a mounting wall connected to the lower end of the guide wall. , the mounting wall of each guide plate is slidably attached to each long wall plate of the nozzle box so that the spacing between the slits can be adjusted in the longitudinal direction. More specifically, a collar is provided on the outside of each long wall plate of the nozzle box to receive and support the mounting wall of each guide plate, and the mounting wall and the collar are connected to each other through a long hole provided in at least one of them to adjust the slide. It is designed so that it can be fastened with bolts.

Next, to explain the details based on the drawings, the second
For convenience of explanation, FIGS. 7 to 7 illustrate the nozzle 2 disposed below the web 1, and the nozzle box 3 is formed in the shape of a long box with an open top along the width direction of the web 1. The middle portions of the long wall plates 4, 4 near the upper ends are tapered upward, and the upper end sides of the long wall plates 4, 4 are parallel to each other. The flanges 6, 6 are integrally bent and connected. Hot air ducts (not shown) are installed at two locations in the longitudinal direction of the bottom plate 7 of the nozzle box, that is, on the opposite side from the surface facing the web 1.
A dynamic pressure suppression plate 11 having a large number of holes 10 formed on its entire surface is installed horizontally above each supply port 9 in the nozzle box.

At the upper end opening of the nozzle box 3, a large number of rectifying plates 12 are fixed by welding or the like at regular intervals in the longitudinal direction between both long wall plates 4, 4.
A hollow frame 13 is positioned and fixed on top by welding or the like.

The hollow frame 13 has a flat rectangular cylindrical shape with parallel upper and lower walls 14, 15 and longitudinally running lateral walls 16, 16, with the flat upper wall 14 directly facing the web 1, and the lower wall 14 facing the web 1 directly. 15 closes the opening top surface of the nozzle box 3, both longitudinal ends are opened into the drying chamber A, and a large number of through holes 17 are provided at predetermined intervals in the longitudinal direction at the center of the top wall 14 in the web feeding direction. It is perforated. The top wall 14 and both lateral side walls 16, 16 are formed by continuous bending.
Each side wall 16 has a vertical lower half 16a and a top wall 1
The upper half 16b connected to 4 has a constant inward inclination angle α
It is sloping.

Guide plates 19, 19 are fixed to the lateral outer sides of the lateral side walls 16, 16 of the hollow frame 13, respectively. Each guide plate 19 is connected to the inclined upper half 16 of each side wall 16.
Guide walls 2 facing in parallel with a certain gap between b
0, a lip 21 which is bent outward from the upper end of the guide wall 20 and diagonally downward in the figure.
It is made of a metal plate and has a mounting wall 22 which is bent horizontally outward from the lower end of the guide wall 20 and is connected to the flange 6 of the nozzle box 3 through the mounting wall 22.
Fixed. That is, bolt holes 23 are provided through the collar 6 at appropriate intervals in the longitudinal direction, and the mounting wall 22 of the guide plate 19 is inserted through the bolt holes 24 through the long holes 24 provided in the collar 6. 25 and a nut 26 so that it can be slid laterally and laterally.

Thus, on both lateral outer sides of the hollow frame 13, a pair of hot air blowing slits 27 extending in the web width direction are formed between the lateral side walls 16, 16 and the guide walls 20, 20 so that the interval can be adjusted. .
The slits 27 are continuous in the longitudinal direction at regular intervals without interruption.

Incidentally, the guide wall 20 of each guide plate 19 is inclined at the same inward inclination angle α as the inclined upper half portion 16b of each horizontal side wall 16 of the hollow frame 13, approximately 70 degrees in the figure, and each slit 27 is inclined at the nozzle. It has a constriction part 27a that communicates with the inside of the box and a run-up part 27b that continues above the constriction part 27a and is spaced at a constant interval. The length L of this run-up portion 27b is set to 5.3 to 21.6 mm, preferably 11 mm, and the gap between the run-up portion 27b is set to 1.0 to 3.5 mm, preferably about 1.8 mm. Needless to say, the slit 27 may be formed into a tapered shape as it goes upward.

In such a case, the hot air blown into the nozzle box 3 from a duct (not shown) through the supply port 9 is first suppressed by the dynamic pressure suppression plate 11, and is distributed over the entire area including the longitudinal direction inside the nozzle box. The flow is filled with uniform pressure, is narrowed down by the inclined parts 5, 5 of the long wall plates 4, 4, and becomes even more uniform, and the flow is rectified by a large number of rectifier plates 12 finely partitioned in the longitudinal direction, and flows into a pair of slits 27. reach. The hot air that has reached each slit 27 passes through the constriction section 27a and the run-up section 27b, and then blows out toward the web 1 from the upper end opening of the slit 27 in the longitudinal direction with uniform wind speed distribution and wind direction. This is especially true for the dynamic pressure suppression plate 11.
This is achieved by a rectifying means consisting of a rectifying plate 12 and a rectifying plate 12. This current plate 12 is for uniformly filling the entire area of the nozzle box 3 with the hot air from the supply port 9, and has a flat plate shape with which the hot air from the supply port 9 collides at right angles, as shown in the illustrated example. Although this is desirable, the structure is not limited to this, and may be built in an inclined or mountain shape. Also, it is important to make the direction of the hot air from the slits 27 uniform in the longitudinal direction of the slits in order to prevent flapping in the width direction of the web. This has been achieved.

Next, the results of actual measurements of the wind speed distribution and wind direction in the longitudinal direction of the slit 27 are shown in FIG. however,
These actual measurement results were obtained under the condition that no webbing was present in the nozzle, and Fig. 8a shows the case where hot air was supplied into the nozzle box from the hot air supply ports 9, 9 at the front and back in the longitudinal direction, and Fig. 8b is the front supply port 9
When opening the rear supply port 9 and closing the rear supply port 9, Fig. 8c
Conversely, the cases in which the front supply port 9 is closed and the rear supply port 9 is opened are shown. And total length 1250mm
A total of 60 baffle plates 12 were arranged below the slits 27 at equal intervals, the gap at the run-up portion 27b of the slits 27 was set to 1.8 mm, and the speed of hot air to the supply port 9 was set to 25 m/sec. This measurement result also confirms that the wind speed distribution and wind direction in the longitudinal direction of the slit 27 are uniform.

Now, hot air is blown out from the pair of slits 27 toward the web 1 at a constant inward inclination angle α, and the area between the upper wall 14 of the nozzle box 3 and the web is surrounded by jets of hot air from both slits 27. A stable positive static pressure is generated in the central zone 28, which supports the web at a predetermined flying level (5 to 7 mm) during high speed travel. The hot air ejected from the slit 27 maintains the static pressure in the zone 28 constant, and a part of it flows into the hollow frame 13 through the through hole 17 provided in the center of the upper wall 14 . The hot air is discharged into the drying chamber A from the open end in the longitudinal direction of the
The hot air flows away in the direction of the arrow a in the figure), and the web is dried by these two flows of hot air. Although it actually depends on the size of the through hole 17, the flow of hot air in the direction of the arrow a plays a major role in drying the web 1.

Here, the flow of hot air in the direction of arrow a, that is, in the lateral outward direction of the static pressure zone 28, is regulated by the surface of the web 1 which is in close proximity and the wall surface 30 of the lip 21 on the nozzle side. Now, if the web 1 flutters for some reason, the flow of hot air is partially regulated by the web, so temporary turbulence may occur, but the flow is rectified and guided by the wall 30. Therefore, the flow of hot air is rectified as much as possible to quickly suppress the flapping of the web and allow the web to run stably at a predetermined floating level. The hot air flows as a wall flow between the web 1 and the wall surface 30, and the presence of the wall surface 30 increases the contact area of the hot air with the web 1, which also contributes to improving the drying processing capacity of the web. . Here, if the lip 21 is formed horizontally parallel to the web 1, negative static pressure will be generated at the extending end of the wall surface 30 of the lip 21 when the hot air leaves the web, causing the web 1 to 21 and tends to come into contact with it. Also, when stopping the operation and passing a new web 1 over the nozzle,
The web is caught on the extending end of the lip 21,
In either case, the web will tear and cause serious trouble, such as making it impossible to drive. Therefore, in the illustrated example, the wall surface 30 is moved diagonally downward from the upper end of the guide wall 20 with respect to the virtual horizontal P along the web 1.
It was tilted at a tilt angle β of 30 degrees. When this is done, there is no possibility that the web 1 will come into contact with the wall surface 30, that is, the extending end of the lip 21.

In addition, since a part of the hot air flowing into the static pressure zone 28 flows into the hollow frame 13 through the through hole 17, the flow of this hot air increases the drying efficiency of the web 1, and also increases the drying efficiency of the web 1 in the static pressure zone 28. Coating liquid mist emitted from the top wall 14 accumulates and adheres to the top surface of the top wall 14.
At the same time, a situation in which the particles re-adhere to the web 1 is also prevented. Incidentally, in the illustrated example, the upper wall 14 is formed as a flat surface facing parallel to the web in order to stabilize the static pressure in the central zone 28, but the upper wall 14 has a convex curved shape with a central convex shape, On the contrary, it may be formed into a concave curved shape, etc., and the point is that the static pressure in the zone 28 is stabilized and there is no sharp part that may come into contact with the web 1. Further, the through holes 17 formed in the top wall 14 may be formed in two rows in the center of the top wall 14 in the web feeding direction, or if they are spaced at regular intervals in the longitudinal direction, the shape and size of the holes 17 may be changed. If the shape and size are constant, the drilling intervals can be changed between the center and both ends in the longitudinal direction, etc., depending on the purpose and use.

Finally, regarding the opening of the slit 27, the upper end of the guide wall 20 is naturally rounded due to the bending process of the lip 21.
The height is set to be flush with the upper surface of the guide wall 20 or lower, so that the web 1 will not come into contact with the upper end of the guide wall 20 and be damaged. This is particularly problematic when the web is passed between the upper and lower nozzles 2 in the drying chamber A prior to drying.

Although the entire structure of the illustrated nozzle is as described above, the present invention is not limited to this.
Various design changes are possible.

In addition, in the illustrated example, from the duct to the nozzle box 3
Although a dynamic pressure suppression plate 11 and a rectifying plate 12 are installed in the nozzle box as means for rectifying the hot air supplied through the supply port 9, these rectifying means are not essential to the implementation of the present invention. Even if it is implemented, only one of the dynamic pressure suppressing plate 11 and the rectifying plate 12 may be installed.

Further, in the illustrated example, the hollow frame 13 is arranged and fixed on the upper part of the nozzle box 3, but this hollow frame 13 is not necessarily necessary, and what is important here is that the upper wall 14 for forming the static pressure zone 28 and the pair of It is a horizontal side wall 16 for forming a slit 27,
The lower wall 15 is not essential. two slits 2
7 need not have the same shape. Also hollow frame 13
When adopting this, the hot air flowing into the drying chamber A may be actively sucked by a suction fan, and it is also conceivable to discharge the flowing hot air to the outside of the drying chamber A.

As explained above, according to the present invention, the outward lip 21 is bent obliquely downward from the upper end of the guide wall 20 constituting the outer wall of each slit 27, and the hot air from each slit 27 is directed toward the movable side web. 1, the wall surface 30 of the lip 21 on the nozzle side
It was decided that the flow would be regulated so that it would flow away laterally and laterally. Therefore, even if flapping occurs in the web 1, the lip 21 can quickly suppress the flapping and stabilize high-speed running of the web. Since the lip 21 actively promotes contact of hot air to the surface of the web, it increases the drying efficiency of the web and also contributes to preventing uneven drying.

Since the lip 21 is bent diagonally downward from the upper end of the guide wall 20, the lip 21
Unlike the conventional configuration in which the lip 1 is formed horizontally parallel to the lip 1, the web does not come into contact with the extending end of the lip 21 when the web is passed over the nozzle prior to operation or while the web is running. It will not cause serious problems such as tearing or damage. Further, since the upper end of the guide wall 20 does not have an edge due to the bending of the lip 21, even if the web 1 comes into contact with the upper end, damage to the web can be well prevented.

Separate guide plates 19, 1 are provided on the lateral outer side of the lateral side walls 16, 16 connected to the top wall 14 of the nozzle box 3.
9 by attaching each lateral side wall 1
6 and the guide wall 20 of each guide plate 19 a series of slits 27 can be formed. At this time, the upper end of the guide wall 20, which determines the important opening of the slit 27, is reinforced by bending the lip 21 and is finished in a straight line, making it easy to adjust the slit gap. Moreover, since the mounting wall 22 of each guide plate 19 can be slidably attached to each long wall plate 4 of the nozzle box 3 so that the spacing between the slits 27 can be adjusted in the longitudinal direction, it is possible to adjust the distance between the slits 27 in the longitudinal direction. When necessary, the slits 27 can be easily fine-tuned to a series of appropriate spacings in the longitudinal direction on site. Together, these have the advantage of ensuring that the velocity distribution and direction of the hot air in the longitudinal direction of the slit 27 are made uniform.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view showing an outline of a floating drying apparatus to which the present invention is directed. 2 to 7 show a nozzle according to the present invention,
Fig. 2 is an external perspective view, Fig. 3 is a plan view, Fig. 4 is a sectional view taken along the - line in Fig. 3, Fig. 5 is an enlarged front view of main parts, Fig. 6 is a side view, and Fig. 7 is a It is a bottom view. FIGS. 8a, b, and c are charts showing the measurement results of the wind speed distribution and wind direction from the slit using the nozzle according to the present invention. FIG. 9 is a longitudinal sectional front view of a conventional nozzle. 1... web, 2... nozzle, 3... nozzle box, 4... long wall plate of nozzle box, 6...
...Brim, 7... Bottom plate of nozzle box, 9... Hot air supply port, 11... Dynamic pressure suppression plate, 12... Rectifier plate, 13... Hollow frame, 14... Top wall, 16...
Lateral wall connected to the top wall, 17...Through hole, 19...
Guide plate, 20... Guide wall, 21... Lip,
22... Mounting wall, 27... Slit, 28... Static pressure zone, 30... Wall surface.

Claims (1)

[Scope of Claims] 1. A long box-shaped nozzle box 3 along the width direction of the web 1 has a pair of slits 27 extending in the width direction of the web 1 on the upper surface side facing the web 1. Hot air is blown out from each slit 27 toward the web 1, and static pressure is generated in a zone 28 between the nozzle box 3 and the web 1 surrounded by two jets of hot air from the pair of slits 27. In a floating drying nozzle that dries the web 1 with hot air while supporting the web 1 from the nozzle box 3 at a constant floating level, an upper wall 14 of the nozzle box 3 facing the web 1 is provided on both sides of the upper wall 14 in the web feeding direction.
4, and has guide plates 19, 19 attached to the opposing long wall plates 4, 4 of the nozzle box 3, respectively, on the lateral outer sides of the lateral side walls 16, 16, and each guide The plate 19 has a guide wall 20 forming a series of slits 27 between the plate 19 and the lateral side wall 16.
, an outward lip 21 formed by bending diagonally downward from the upper end of the guide wall 20 ;
and a mounting wall 22 connected to the lower end of the nozzle box 3, and the mounting wall 22 of each guide plate 19 is slidably attached to each long wall plate 4 of the nozzle box 3 so that the spacing between the slits 27 can be adjusted longitudinally. A floating drying nozzle characterized by: 2 A collar 6 is provided on the outside of each long wall plate 4 of the nozzle box 3 to receive and support the mounting wall 22 of each guide plate 19, and the mounting wall 22 and the collar 6 are connected to the long wall plate 4 provided on at least one of them. The floating drying nozzle according to claim 1, which is bolted through the hole 24.