JPS6042586A - Nozzle for floating drying - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention is 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 passed through a drying chamber, and dries the web while supporting it at a predetermined floating level in the drying chamber.

FIG. 1 shows an outline of a typical floating drying device, in which a large number of nozzles 2 are arranged in an alternating manner with a web W sandwiched between them in a drying chamber l, and Hot air is blown onto the web W from slits 15 on the nozzle side provided on the left and right sides of the surface, and the web W is dried with hot air while being guided in an approximate sine curve shape.

This type of nozzle 2 is generally provided with a pair of slits 7+, 15, and 15 along the web width direction on the left and right sides of the upper surface of the nozzle body 11 facing the web W, as shown in FIG.・Hot air is blown from 15 towards the web W, and a positive static pressure is created in a zone 40 surrounded by two jets of hot air from each slit 15 between the web W and the upper wall 29 of the nozzle body 11 facing thereto. A type of drying method is known in which the web W is dried while being generated and supported at a predetermined floating level. Soba Web W
In order to increase throughput by sending the web at high speed, the distance between the opposing surfaces of the nozzle top wall 29 and the web W is extremely small, and in reality it is often set to less than lQm+a, generally 5 to 7 fins.

However, the conventional nozzle top wall 29 is simply formed as a flat surface that is continuous with the opening of the slit 15. However, in the case of a web W that is wide and requires low tension, the frictional resistance with the air is extremely small and the thickness is thin, so even if the web W is subjected to a slight external force or other factors, the web W will not move in the feed direction or width direction. butter) and easily come into contact with the nozzle side. According to the inventor's observation, the web W has both slits 15 and
Most often, the nozzle contacts the left and right intermediate portions of the nozzle top wall 29 between the nozzle parts 15 and 15.

Such contact troubles are caused by the fact that the static pressure in the static pressure zone 40 is not uniformly stable in the web feeding direction (left and right) and the web width direction (front and back). I think,
Since the web W is held up by the wind pressure at the locations directly hit by the hot air blowing out from each slit 15, the static pressure distribution in the static pressure zone 40 is high at the left and right ends near both slits 15, and at the center of the left and right. As a result, the web W running at high speed waves at the opposite portion of the nozzle top wall 29 and comes into contact with the middle portion of the top wall 29. Furthermore, it is considered that the web W comes into contact with the opening end portion of the slit 15 located on the downstream side in the web feeding direction.

Therefore, conventionally, a large number of hot air outlets are provided through the nozzle upper wall 29 at regular intervals in the left and right center portions of the nozzle top wall 29, and hot air is ejected from the hot air outlets to reach the left and right center portions of the static pressure zone 40. Attempts have been made to increase the web lifting force, but this makes the static pressure zone 40 unstable as a whole due to the hot air blown directly into it, causing slight flapping in the web W. It's not a fundamental solution. It is difficult to adjust the volume of hot air from the hot air outlet, and it is not practical.

This invention focuses on this fact, and the nozzle top wall 29
The aim is to improve the shape of the top wall 29 so that the extremely thin web W is brought as close as possible to the top wall 29 so that the web W does not come into contact with the nozzle side even when fed at high speed.

Hereinafter, the details will be explained based on the drawings. FIGS. 2 to 6 show the floating drying nozzle according to the present invention, and for convenience of explanation, show the nozzle arranged below the web W. The basic structure of this nozzle 2 is a long box-shaped nozzle body 11 that is hidden at the front and back and is open at the top. A rectifying plate 12 is fixed in the opening at the upper end of the nozzle body 11, and a nozzle body 111J has two open ends. A lid frame 13 having a trapezoidal cross section is fixed in the longitudinal direction, and guide plates 14 are arranged on both left and right sides of the lid frame 13 to form a pair of hot air blowing slits on the left and right sides of the L side facing the web W. The basic structure is that 15.15 are formed in series along the width direction of the web W.

In FIG. 3, the nozzle body 11 has left and right side walls 16R and 1.
The upper half of 6L is inclined inward, and this inclined constriction part 17
The upper side is folded vertically to open it, and the overall cross-sectional shape is tapered at the top.

The front and rear ends are closed with end walls 18. A flange 1 for fixing the guide plate 14 by extending the left and right side walls 16R and 161 horizontally outward at the upper end opening of the nozzle body 11.
9 is formed. Front and rear 2 of the bottom wall of the nozzle body 11
An air supply port 20 for supplying hot air connected to a duct (not shown) is formed in an oval shape at the location, and this air supply port 20
A porous buffer plate 21 is installed directly above the main body to remove the directivity of the hot air and to equalize the wind pressure inside the main body.

At the upper end opening of the nozzle body 11, the current plate 12 is located at the sixth
As shown in the figure, they are arranged vertically at regular intervals in the front and rear, and thereby partition the upper end of the inclined constriction part 17 of the nozzle body 11 and the open end 1] in the front and back, and from inside the nozzle body 11. Directivity is imparted to the hot air directed toward each slit 15, and the direction of the hot air blown out from each slit 15 is stabilized.

In order to equalize the wind pressure within the nozzle body 11, the rectifier plate 12 and the air supply port 20 are partitioned by a partition wall 23, and a first
A pressure regulation chamber 24 and a second pressure regulation chamber 25 are partitioned. The left and right ends of the partition wall 23 are bent upward to form standing walls 26, 26, and slits 15, 1 are formed between the standing walls 26, 26 and the left and right side walls 16R, 16L of the nozzle body 11, respectively.
Parallel pressure regulating passages 27 and 27 are formed in front and rear of the pressure regulating chamber 5, and the first and second pressure regulating chambers 24 and 25 are communicated with each other through the pressure regulating passages 27. The gap between the pressure regulating passages 27 is the same as or slightly larger than the gap between the slits 15, and during steady operation, hot air flows into the left and right side walls 16R of the nozzle body 11 in the upper second pressure chamber 25.
・Flows along 16L. Note that the 1 section wall 23 has bolts 2
8 to the inner bottom wall of the nozzle body 11.

In FIGS. 3 and 4, the lid frame 13 has a trapezoidal cross section, and has a flat upper wall 29 facing the web W and left and right side walls 30 whose upper ends are connected to the left and right ends of the upper wall 29. In FIG. 1, the bottom wall 31 having a U-shaped cross section is fixed and formed hollow.

The hollow lid frame 13 is connected to the rectifying plate 12 via the bottom wall 31.
It is placed and fixed on the group and closes the top surface of the opening of the nozzle body 11. The left and right width of the lid frame 13 is narrower than the opening width of the nozzle body 11, and as shown in FIG. , an upper half 30 connected to the upper wall 29
b are each slanted inward by about 1.

Guide plates 14, 14 are arranged on the lateral outer sides of the left and right side walls 30, 30 of the hollow frame 13, respectively.

Each guide plate 14 has an inclined guide wall 32 facing parallel to the inclined upper half 30b of each side wall 3o of the 1M frame 13 at a constant interval, and an inclined angle of about 30 degrees from the upper α111 of the guide wall 32. A lip 33 bent diagonally downward and a mounting wall 34 extending horizontally from the lower end of the guide wall 32 are formed in series. This mounting wall 34 has long holes 34a transparently provided at appropriate intervals in the front and back direction, and the bolts 35 inserted through these holes are passed through the bolt holes provided transparently in the flange 19 on the nozzle body II side, and then inserted into the nuts 36. By screwing in, the entire guide plate 14 is fastened to the lid frame 13 so that it can be slid outwardly.

A pair of slits 15 and 1 extending in the web width direction are provided between each guide plate 14 and the left and right side walls 3° and 30 of the lid frame 13.
5 are formed in a continuous series. Each slit 15 is formed between the lower half 30a of the side wall of the lid frame 13 and the guide plate 14.
a tapered constriction portion 15a sandwiched between the guide walls 32;
It consists of a run-up portion 15b sandwiched between the side wall upper half portion 30b of the lid frame 13 and the guide wall 32 of the guide plate 14 with a constant gap. The length of the run-up portion 15b is set to 5.3 to 21.6++++, preferably around 1III11, and the gap C is 1.0
It is set at ~2.5 degrees, or more specifically, around 1.8 crimes. The run-up portion 15b of this pickpocket 1.15 may also be formed in a tapered shape. The inclination angle of the hot air blown out from the slit 15, that is, the inclination angle α of the run-up portion 15b, is set to about 70 degrees.

What should be noted here is the upper surface 29a of the upper wall 29 of the lid frame 13.
is formed into a step-like flat surface by removing the inner downwardly inclined wall portion 39 which is continuous with the upper end of the side wall upper half portion 30b. The reason why the upper wall 29 is formed in a step-like manner than the opening light of the single slits 15 is to prevent the web W from coming into contact with the upper wall 29. therefore,
This level difference, that is, each of the left and right side walls 30 - the upper end and the upper wall 2
If the vertical height E with respect to 9 is too shallow, it will not be effective, and if it is too deep, the web will become loose, so it should be 1.0 to 3.0.

More preferably, it is within the range of 1.0 to 1.5 m+i.

In such a case, as shown in Fig. 3, hot air supplied from a duct (not shown) into the nozzle body 11 through two air supply ports 20 at the front and back collides with the loose IH plate 21 and is divided by its many holes. 5 directivity is removed, and moves to the first pressure regulating chamber 24 in the lower stage. Next, the second full pressure chamber 25 in the upper stage is
Move to. Since the gap in the pressure regulating path 27 is small when
Variations in pressure in the first pressure regulating chamber 24 are almost eliminated.

The main stream of hot air that has flowed into the second pressure regulating chamber 25 flows through the nozzle body 11
Flows along the left and right side walls 16R and 16L.

As the cross-sectional area decreases at the inclined aperture portion 17, the flow increases in speed and is directed vertically by the 5 rectifying plates 12, reaching the left and right slits 15. Inside the slit 15, the hot air is accelerated according to the cross-sectional change of the constricted part 15a, and
b while being guided inward and obliquely, and collides with the web W obliquely.

In this slit 15, as in the case of the pressure regulating path 27,
The bottom plate 29 of the hollow frame 13 is connected to the sulin 1~ from the second pressure regulating chamber 25.
Because it acts to block the hot air moving to 15,
Variations in the wind pressure in the front and rear directions in the pressure regulating chamber 25 can be sufficiently eliminated, and the direction and pressure of the hot air blown out from the slit 15 are made uniform over the entire length in the direction. Therefore, it is possible to reliably prevent the web W from coming into contact with the next nozzle O due to not only the fluttering of the web W but also waving in one width direction, and the web W from being wrinkled. Moreover, since the hot air blown out is uniform, the web W is dried uniformly over its entire length in the width direction.

Now, hot air is blown out from the left and right sulins) 15 and I5 at a constant inward inclination angle α toward the web W, and the lid frame 1
Both slits 1 are formed between the upper wall 29 of 3 and the web W.
A stable positive static pressure is created in zone 40 surrounded by jets of hot air from 5.

This allows the web W running at high speed to be set at a predetermined float-F level (5
~7mm). While maintaining the static pressure in the static pressure zone 40 constant, most of the hot air ejected from both slits 15 flows away laterally to the left and right, and the web is dried by these two flows of hot air. In reality, the flow of hot air laterally outward of the static pressure zone 40 is largely involved in drying the web W.

Here, the flow of hot air in the lateral outward direction of the static pressure zone 40 is regulated by the surface of the web W in the close state and the upper wall surface 33a of the lip 33 on the nozzle side.

Now, if Web W is disrupted for some reason.

The flow of hot air is partially regulated by the web.

It is thought that temporary turbulence may occur, but since it is guided by the wall surface 33a, if this hot air flows, it will be rectified as much as possible, quickly suppressing the fluttering of the web W, and keeping the web at a predetermined floating level. It runs stable. The hot air flows as a wall flow between the web W and the wall surface 33a, and the existence of the wall surface 33a increases the contact area of the hot air with the web. The wall surface 33a may be formed horizontally parallel to the web W, but in this case, the extension 1'l of the wall surface 33a
In step 1, when the hot air is released from the web, a small static pressure is generated, and there is a fear that the web W may come into contact with the extending end of the wall surface 33a. Therefore, in the illustrated example, the wall surface 33a is inclined downward at an oblique angle of approximately 30 degrees from the upper end of the wall 32 to a virtual horizontal line along the web W. With this, there is no possibility that the web W will come into contact with the wall surface 33a, that is, the extending end of the lip 33.

According to the invention, in particular, the upper surface 29a of the -L surface wall 29 of the lid frame 13 facing the web W is connected to the air outlet θ of each left and right slit 15 via the inclined wall portion 39 to a flat surface lower than 1. Since 1 web W is formed on the upper surface wall 29
Never come into contact with. Also.

Since the presence of the inclined wall portion 39 greatly contributes to stabilizing the static pressure in the static pressure zone 40, the web W is always supported at a constant floating level on the upper surface wall 29 in a stable state. Therefore, even if the web W is brought as close as possible to the two-sided wall 29 of the nozzle and is run at high speed, the web W does not come into contact with the nozzle side including the top wall 29, thereby improving drying efficiency. In addition, it is possible to reliably prevent the web W from being soiled by the coating liquid mist adhering to the two-sided wall 29 and from being scratched by contact.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing a float ink drying apparatus to which the present invention is directed. Figures 2 to 5 show the nozzle according to the present invention, in which Figure 2 is an external perspective view, Figure 3 is a longitudinal sectional front view, and Figure 4 is
The figure is an enlarged cross-sectional view of the main part of the peripheral structure of Figure 3, and Figure 5 is a cross-sectional view taken along the line A-A in Figure 3.
FIG. 6 is a sectional view taken along the line BB in FIG. 3. 11... Nosuru body. 12... Rectifier plate. 13... Lid frame. I 4... Guide plate. 15... Slit. 20...Air supply port. 29...Top wall of the lid frame. 29a...Top surface of the top wall of the lid frame. 30...Left and right side walls of the lid frame. 32... Guide wall. 39... Slanted wall part. 40... Static pressure. W...Web. Figure 3 Figure 4

Claims (1)

[Claims] (1) An upwardly open type that is long along the width direction of the web W.
On the left and right sides of the upper surface of the nozzle body 11 facing the web W, there are a series of slotted throats 15 extending in the width direction of the web W.
5, the hot air is supplied to the nozzle body 11 through both Surino I and
15.Blowout from 15 to Web W, Web W
In a floating drying nostle that dries with hot air while supporting it at a constant floating level from the nozzle body 11,
Opening of the nozzle body 11 A lid frame 13 having an upper wall 29 facing the web W and left and right side walls 30 whose upper ends are connected to the left and right ends of the two-sided wall 29 is fixed in the longitudinal direction. The left and right side walls 30, 30 of the lid frame 13 and the guys l"lf arranged on the lateral and outer sides of the left and right side walls 30, 30.
The slits 15 are formed between the slits f114 and f14, respectively, and the E surface 2 of the top wall 29 of the lid frame 13 is
9a or the left and right side walls 30 that constitute the slits 15 and 15.
Inner downward inclined wall portions 39, 39 continuous to the upper end of 30
A floating drying nozzle, characterized in that it is formed on a stepped flat surface through.