JP3033270B2 - Exhaust device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for manufacturing a plastic film, in which sublimates and evaporated substances volatilized from a film surface are reliably removed from the system, so that the sublimates are condensed and adhered to a ceiling and then dropped again. The present invention relates to an exhaust device capable of preventing a danger of adhering to a film surface.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory plan view showing an example of an apparatus for producing a plastic film. A molten polymer supplied from an extruder 2 is discharged from a T-die apparatus 3 to form a thick film 1. In the apparatus shown in the figure, it is then fed to a longitudinal stretching machine 4 and stretched at a predetermined magnification in the vertical direction while heating, and then guided to a horizontal stretching machine 5 and stretched at a predetermined magnification in the horizontal direction. The horizontal stretching machine 5 includes a preheating section 5a, a stretching section 5b, and a heat treatment section 5c, and heats the film to a temperature suitable for each process in each section. After passing through the transverse stretching machine 5, the film 1 passes through the cooling unit 6,
It is wound up. It is known that the order of stretching may be changed in various ways other than the illustrated ones.

Unreacted monomers and oligomers or additives for improving transparency and mechanical properties are mixed in the film running in the above-mentioned manufacturing apparatus. Evaporates or sublimates from the high temperature film surface inside. These evaporants or sublimates condense and adhere to the cabin wall surface, especially to the ceiling, not only contaminating the cabin itself or related equipment, but also cause these adherents to move from the ceiling to the film surface running by mechanical vibration. It falls down and causes a problem of deteriorating the quality of the film.

[0004] For example, FIG. 4 is a side sectional view showing a part of a horizontal stretching machine 5. An exhaust duct 11 is formed in a ceiling 5 D, and an exhaust fan 1 provided in an opening 11 a of the duct 11.
2 to evaporate or sublimate in the direction of arrow U,
It is configured to exclude in the direction. However, it is impossible to completely remove the evaporant or the sublimate from the cabin, and it is inevitable that the condensate S adheres to the ceiling 5D or the like. 1
(See arrow D in FIG. 4).

Therefore, a cloth 1 is placed between the film 1 and the ceiling 5D.
3, the condensate S falling as described above is received by the cloth 13 so as not to drop directly on the film 1.

[0006]

However, the cloth 13 is directly exposed to ascending evaporants and the like, and receives a drop of the condensate, so that the cloth 13 is contaminated in a short period of time. It would fall onto the film, and the cloth 13 had to be changed frequently.

The inventors of the present invention have conducted research on the purpose of providing an exhaust device which does not cause the inconvenience of dropping a condensate onto a film without disposing the cloth 13, let alone replacing the cloth 13. Again, the present invention could be completed.

[0008]

According to the present invention which has achieved the above object, a pair of first blast nozzles for forming a vortex air flow having a swirl axis in a substantially horizontal direction above a film surface are provided facing each other, The gist of the invention is that a second blast nozzle for forming an air curtain is provided above the spiral airflow, and a suction port for exhaust is opened on a surface intersecting with the swirl axis of the spiral airflow. .

[0009]

A swirling airflow having a swirl axis in the horizontal direction above the running film is formed by the gas injection from the first blowing nozzle provided facing the surface, and the evaporant and sublimate rising from the film surface are removed. The entrained material is sucked into a suction port provided in a plane that is axially forward of the spiral airflow and intersects with the swirl axis, thereby removing evaporated substances and the like outside the machine.

Further, since an air curtain is formed by the second blast nozzle above the spiral air flow, even if a part of the evaporant etc. jumps upward from the spiral air flow, it is shut off by the air curtain. So that evaporants etc. do not rise through this air curtain,
The air is re-engaged with the spiral airflow formed below and exhausted.

Most of the evaporant and sublimate generated from the film are removed to the outside of the machine through the suction port, and the condensate adheres to the ceiling of the machine room and is surely dropped onto the film surface. Can be prevented.

[0012]

FIG. 1 is a perspective explanatory view showing a typical embodiment of the present invention, and FIG. 2 is a side sectional view of FIG. Film 1
The blowing devices 22, 22 are located above the running direction and on both sides.
Are provided above the film 1 so as to face the first blast nozzles 24, 24... With the film 1 interposed therebetween, and further above the second blast nozzles 23, 23.
Is provided. Above the film 1 is an exhaust duct 2
And an exhaust fan 21 is provided in the exhaust duct 21.
b, and the suction port 21A is formed in a plane perpendicular to the film running direction.

As shown in FIG. 2, gas such as air is blown obliquely downward from the first blast nozzles 24, 24,..., And a vortex air flow having a swivel axis parallel to the film running direction above the film 1. Yr and Yl are formed. The spiral airflows Yr and Yl move so as to be sucked toward the suction port 21A, and are finally continuously discharged into the suction duct 21.

In forming the swirling airflows Yr and Yl, the first blowing nozzles 24 and 24 are provided to face each other, so that the blowing airflows collide with each other to form a swirling airflow. The front side wall 22A of the blowing device 22 preferably has a curved surface and guides the air flow to form a swirling air flow.
A swirling airflow may be formed by utilizing the swirling suction flow.

On the other hand, similarly, a gas such as air is blown obliquely downward from the second flammable nozzles 23, 23,..., And the gas forms an air curtain at the upper part of the spiral airflow Yr, Yl. Become. Therefore, the evaporant or the like rising from the upper surface of the film 1 in the direction of the arrow U is caught in the spiral airflow and transported forward. The curtain prevents the rise and falls again, and is again caught in the spiral airflows Yr and Yl and removed through the suction port 21A. That is, even if there are evaporants and the like that rise through the spiral airflows Yr and Yl, they are generated by the second blast nozzles 23 and 23.
The air curtain formed by... Prevents further upward movement and acts so as to be drawn into the swirling airflows Yr and Yl. As a result, evaporants and the like are led into the suction duct 21. Therefore, since the evaporant and the like do not adhere to the ceiling or the like in the cabin, the contamination of the film by these substances is prevented. Even if some of the evaporant adheres to the ceiling or the like and falls, it is prevented from falling onto the film surface by the action of the air curtain.

The preferred air volume, wind speed and injection angle at the first and second blast nozzles 24 and 23 are such that the width of one blast device 22 is 1.5 to 2.5 m and the first The interval between the nozzles 24, 24 is 200 to 50
0 mm, and the exhaust air volume from the suction duct is 60 to 70 m ³
/ Min / unit is as follows.

(First eruption nozzle 24) Ejection air volume: 2-3 m ³ / min. Table Ejection wind speed: 7-10 m / sec Ejection angle (b): 15-20 degrees (Second eruption nozzle 23) Ejection air volume: 15 ２０20m ³ /min./unit Jetting wind speed: 3-4m / sec Jetting angle (a): 5-10 degrees

That is, air or the like is jetted at a high wind speed from the first blast nozzle 24 that generates a swirling airflow, so that a swirling airflow can be reliably formed, and a large air volume is generated from the second blast gas nozzle that forms an air curtain. The air is blown out to prevent the rise of vapors and the like.

The opening shapes (round holes, slits, etc.) and the number of the first and second blast nozzles are arbitrary, and the orientations of the nozzles and the suction ports with respect to the film running direction are as shown in FIG. The present invention is not limited to this. For example, a suction port may be provided in a plane parallel to the film running direction.

[0020]

According to the present invention, as described above, it is possible to reliably remove the evaporant and sublimate generated from the film, and these condensates fall on the film surface to form the film. It is now possible to prevent contamination.

[Brief description of the drawings]

FIG. 1 is a perspective explanatory view showing an embodiment of the present invention.

FIG. 2 is a schematic side sectional view of FIG. 1;

FIG. 3 is an explanatory plan view showing an example of a film manufacturing apparatus.

FIG. 4 is a side sectional view of a conventional transverse stretching machine.

[Explanation of symbols]

 11, 21 Exhaust duct 21A Suction port 23 Second fume nozzle 24 First fume nozzle

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-3-42634 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B29C 55/02-55/28 B29C 47 / 78-47/90 F24F 7/06

Claims (1)

(57) [Claims] 1. An exhaust system for removing sublimates or evaporates generated from a film surface in a process of producing a plastic film to an outside of a system, wherein a spiral airflow having a swirling axis in a substantially horizontal direction above the film surface is formed. A pair of first blast nozzles are provided facing each other, a second blast nozzle for forming an air curtain is provided above the vortex airflow, and an exhaust gas is provided on a surface intersecting the swirl axis of the vortex airflow. An exhaust device characterized by having a suction port opened.