Film forming apparatus

Abstract

The present application relates to a film forming device, comprising: a cooling unit (104) for cooling a molding material discharged from a mold (102); and a rectifying unit (105) for rectifying cooling air blown from the cooling unit (104). The rectifying unit (105) includes a suction unit for sucking the cooling air.

Description

TECHNICAL FIELD

[0001] The present application relates to a film molding apparatus. BACKGROUND

[0002] A film molding apparatus is known, which extrudes a molten molding material in a film shape from a discharge port of a mold, and solidifies it by cooling air from a cooling section to mold a film. In the past, a film molding apparatus has been proposed, which controls the film thickness within a target range by adjusting the width of the discharge port, the air speed of the cooling air from the cooling section, and the air temperature.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-177348 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The cooling air blown from the cooling section is a jet flow, and its flow becomes turbulent. If the cooling air is turbulent, the cooling capacity differs depending on the position of the discharge port in the extending direction, and even if it is the same position, the cooling capacity differs depending on the time, as a result, the film thickness of the molded film becomes uneven. Also, the cooling air as a turbulent flow vibrates the molding material extruded in a film shape, as a result, the quality of the molded film is reduced.

[0008] The present application was completed in view of such a situation, and one of the exemplary objects of one embodiment of the present application is to provide a film molding apparatus capable of reducing the flow turbulence of cooling air.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] In order to solve the above problems, a film molding apparatus of one embodiment of the present application includes a cooling section that cools a molding material discharged from a mold, and a flow regulating section that regulates the flow of cooling air blown from the cooling section. The flow regulating section includes a suction section that suctions the cooling air.

[0011] In addition, any combination of the above configuration elements, a mode in which the configuration elements of the present application are replaced with each other between a method, a device, a system, and the like, is also effective as a mode of the present application.

[0012] EFFECT OF THE INVENTION

[0013] According to the present application, it is possible to reduce the flow turbulence of cooling air. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a view showing the basic structure of a film molding apparatus according to a first embodiment.

[0015] Figure 2 is a sectional view of the suction ring of Figure 1 cut with a plane containing the central axis C.

[0016] Figure 3 is a plan view of Figure 2

[0017] Figure 4 is a sectional view of the suction ring of the modification example according to the first embodiment.

[0018] Figure 5 is a sectional view of the flow straightening portion and its periphery of the film forming apparatus according to the second embodiment.

[0019] Figure 6 is a sectional view of the flow straightening portion and its periphery of the film forming apparatus according to the modification example of the second embodiment.

[0020] Figure 7 is a sectional view of the flow straightening portion and its periphery of the film forming apparatus according to the third embodiment.

[0021] Figure 8 (a) and (b) in (1) are plan views showing examples of the communication path.

[0022] Figure 9 is a view showing the discharge port periphery of the mold of the film forming apparatus according to the modification example of the third embodiment.

[0023] Figure 10 is a view showing the discharge port periphery of the mold of the film forming apparatus according to another modification example of the third embodiment. DETAILED DESCRIPTION

[0024] Hereinafter, the present application will be described based on preferred embodiments with reference to the drawings. The embodiments are examples and not intended to limit the present application, and all features described in the embodiments, combinations thereof are not necessarily essential to the present application. Identical or similar constituent elements, members, and processes shown in each drawing are denoted by the same reference numerals, and repeated description will be appropriately omitted.

[0025] (First Embodiment)

[0026] Figure 1 is a view showing the basic structure of the film forming apparatus 100 according to the first embodiment. The film forming apparatus 100 is provided with a mold 102, a cooling portion 104, a flow straightening portion 105, a pair of guide portions 106, a haul-off machine 108, and a winding machine 110.

[0027] ​Further, hereinafter, an arbitrary direction passing through the center axis C on a plane perpendicular to the center axis C will be referred to as a radial direction, a side close to the center axis C in the radial direction will be referred to as an inner peripheral side, a side away from the center axis C will be referred to as an outer peripheral side, and a direction along a circumference of a circle centered on the center axis C on the plane perpendicular to the center axis C will be referred to as a circumferential direction.

[0028] The molten molding material is discharged in a cylindrical shape from the annular discharge port 102a formed in the mold 102. Air is discharged at an appropriate timing from the air discharge port 102b formed in the center portion of the mold 102 on the inner side of the discharged cylindrical molding material to mold a thin-walled film (hereinafter, also referred to as a "bubble") which is expanded in a cylindrical shape.

[0029] The cooling section 104 is disposed above the mold 102. The cooling section 104 is a hollow annular housing which surrounds the center axis C. The cooling section 104 includes an annular cooling section main body 104a, a supply flow path 104b which extends to the radially inner side from the lower end of the inner peripheral side of the cooling section main body 104a, and a blowout portion 104c which is continuous with the radially inner side of the supply flow path 104b and opens upward. Cooling air is supplied to the cooling section main body 104a from a blower which is not shown. The cooling air supplied to the cooling section main body 104a is blown out from the blowout portion 104c through the supply flow path 104b and is blown to the bubble. Thus, the bubble is cooled. In particular, the blowout portion 104c is formed concentrically with the annular discharge port 102a centered on the center axis C. Thus, the height at which the cooling air contacts the bubble and the amount of air become uniform in the circumferential direction.

[0030] The rectifying section 105 is provided with a suction ring 130 which constitutes a suction section, and at least one (in this example, a plurality of) suction pumps 132. The suction ring 130 is disposed above the cooling section 104. The suction ring 130 and the suction pumps 132 can be suspended from the guide section 106, can be supported by a leg which extends from the cooling section 104, or can be fixed to a frame which is not shown. The rectifying section 105 rectifies the cooling air blown out from the cooling section 104 and reduces flow turbulence of the cooling air.

[0031] A pair of guide sections 106 is disposed above the rectifying section 105 and guides the bubble to a hauler 108. The hauler 108 is disposed above the guide section 106. The hauler 108 includes a pair of nip rollers 118. The pair of nip rollers 118 is driven to rotate by a motor which is not shown and folds the guided bubble into a flat shape while pulling the bubble. A winder 110 winds the folded film to form a film roll 120.

[0032] Figure 2 is a sectional view in which the suction ring 130 is cut by a plane including the center axis C. Figure 3 is Figure 2 is a plan view of Figure 3The image shows the state with the upper wall 134d of the housing 134 of the suction ring 130 removed. (Reference) Figures 1-3 .

[0033] The suction ring 130 has a hollow annular shell 134. The shell 134 has an upper wall 134d, a lower wall 134a, an inner wall 134e, and an outer wall 134f. An annular suction port 134b surrounding a central axis C is formed on the inner circumferential side of the lower wall 134a of the shell 134. The suction port 134b opens downward. A plurality of flexible tube ports 134c are formed on the outer circumferential side of the shell 134. The plurality of flexible tube ports 134c are not particularly limited, but are preferably formed at equal intervals in the circumferential direction as shown in the figure. In the example shown, the plurality of flexible tube ports 134c are formed on the upper wall 134d, but they may also be formed on the lower wall 134a.

[0034] Multiple hose ports 134c are connected to at least one suction pump 132 via hose 136. When the suction pump 132 is activated to draw air from the housing 134 via hose 136, the cooling air rising along the bubbles blown out of the cooling section 104 is drawn into the housing 134 from the suction port 134b. By drawing cooling air from the cooling section 104 downstream, turbulence in the cooling airflow is reduced. Furthermore, the height of the suction ring 130 can be determined based on experiments, simulations, or insights.

[0035] A cylindrical baffle plate 138 is provided inside the housing 134. The baffle plate 138 divides the internal space of the housing 134 into a suction port 134b side and a hose port 134c side. The baffle plate 138 has multiple through holes 138a connecting the suction port 134b side and the hose port 134c side. In this example, the multiple through holes 138a extend radially. Cooling air drawn into the housing 134 from the suction port 134b flows into the hose port 134c side through the through holes 138a.

[0036] Here, consider the case where there is no baffle 138. The hose opening 134c is discontinuous in the circumferential direction. Therefore, the suction force is stronger in the portion of the suction port 134b near the hose opening 134c, i.e., the portion of the suction port 134b located radially inside the hose opening 134c, and weaker in the portion of the suction port 134b away from the hose opening 134c, i.e., the portion of the suction port 134b not located radially inside the hose opening 134c. In other words, the suction force of the suction port 134b becomes uneven in the circumferential direction. In contrast, by providing the baffle 138 between the hose opening 134c and the suction port 134b, the airflow closer to the upstream side (i.e., the inner circumferential side) than the baffle 138 becomes more uniform, and the suction force from the suction port 134b becomes more uniform in the circumferential direction. By drawing cooling air with a more uniform suction force in the circumferential direction, the flow of cooling air rising along the bubbles also becomes more uniform in the circumferential direction.

[0037] A labyrinth 140 is provided on the inner peripheral side of the baffle 138. The labyrinth 140 is a portion having a flow path that is intricately curved. In the present embodiment, the labyrinth 140 has a corrugated flow path 142 in cross section. In the present embodiment, the flow path 142 is formed by alternately arranging, in the radial direction, a cylindrical plate 144 fixed with a gap formed between the upper wall 134d and the cylindrical plate 144 fixed with a gap formed between the lower wall 134a. By providing the labyrinth 140, the flow path from the suction port 134b to the baffle 138 is lengthened, and the air flow in the circumferential direction becomes more uniform, as a result of which the suction force from the suction port 134b becomes more uniform in the circumferential direction.

[0038] A smoothing flow path 146 is provided on the outer peripheral side of the baffle 138. The smoothing flow path 146 is a flow path partitioned by a plurality of partition walls 148 curved in the circumferential direction and extending in the circumferential direction so as to respectively face the plurality of hose ports 134c. By providing the smoothing flow path 146 extending in the circumferential direction, the distance that the air travels after passing through the baffle 138 to reach the hose port 134c becomes longer.

[0039] According to the present embodiment described above, the cooling air that rises along the bubbles blown out from the cooling portion 104 is sucked by the rectifying portion 105. Thereby, the flow disturbance of the cooling air that rises along the bubbles is reduced.

[0040] Also, according to the present embodiment, the baffle 138, the labyrinth 140, and the smoothing flow path 146 are provided inside the suction ring 130. Thereby, the suction force from the suction port 134b becomes more uniform in the circumferential direction, and the flow of the cooling air becomes more uniform in the circumferential direction.

[0041] Next, a modification related to the first embodiment will be described.

[0042] Figure 4 is a cross-sectional view of the suction ring 130 related to the modification of the first embodiment. Figure 3 Corresponding to Figure 2 In the suction ring 130 related to the modification, the annular suction port 134b of the suction ring 130 is formed in the inner wall 134e of the housing 134. Therefore, the suction port 134b is opened to the inner peripheral side. In the illustrated example, the suction port 134b is provided on the upper side of the inner wall 134e, but can be provided on the lower side, or can be provided on the central portion of the upper and lower sides. According to the present modification, the same effects as the first embodiment can be achieved.

[0043] (Second Embodiment)

[0044] In the second embodiment, the membrane forming apparatus is described as having a rectifier plate for rectifying the cooling air from the cooling section. In the second embodiment, the cooling air from the cooling section is drawn into a space defined by the rectifier plate. Hereinafter, the differences from the first embodiment will be described.

[0045] Figure 5 This is an enlarged cross-sectional view showing the rectifier 205 and its surrounding area of ​​the membrane forming apparatus 200 according to the second embodiment.

[0046] The film forming apparatus 200 includes a mold 102, a cooling unit 104, a rectifier 205, a pair of guide units 106, a traction machine 108, and a winding machine 110. The display of the pair of guide units 106, the traction machine 108, and the winding machine 110 is omitted.

[0047] The rectifier section 205 includes at least one (in this example, multiple) rectifier plates 220 for rectifying cooling air, a suction ring 130 constituting the suction section, and a suction pump 132. Furthermore, the shape and configuration of the suction ring 130 are the same as in the first embodiment, therefore description is omitted. The multiple rectifier plates 220 are cylindrical plates with different diameters. The multiple rectifier plates 220 are centered on a central axis C (… Figure 5 (Not shown in the figure) are arranged in concentric circles around a central point. Although not particularly limited, in this example, multiple rectifier plates 220 are mounted and fixed to the upper wall 104d of the supply flow path 104b. The rectifier plates 220 located further out radially are positioned at a higher height at their upper ends.

[0048] The space 250 between the bubble and the cooling section 104 is divided into multiple spaces 250a to 250d by the rectifier plate 220. A connecting hole 220a is formed on the rectifier plate 220 to connect the multiple spaces 250a to 250d.

[0049] The suction ring 130 is configured to block the space 250d between the outermost rectifier plate 220 and the cooling section body 104a in the radial direction. In this embodiment, it is configured to block the upper end of the space 250d between the outermost rectifier plate 220 and the cooling section body 104a in the radial direction. When the suction pump 132 is operated, air in the plurality of spaces 250a to 250d is drawn in through the suction ring 130, and as a result, the cooling air blown out from the cooling section 104 is drawn into the plurality of spaces 250a to 250d.

[0050] In addition, by the pressure in the spaces 250b to 250d being reduced by suction by the suction ring 130, sometimes a bubble is drawn toward the spaces 250b to 250d. If the drawn bubble contacts the rectifier plate 220, the bubble can be damaged. In relation to this, by forming the communication hole 220a also on the innermost rectifier plate 220, when the bubble is about to contact the rectifier plate 220, external gas flows from the communication hole 220a of the innermost rectifier plate 220, the pressure in the spaces 250b to 250d rises, and the bubble is prevented from contacting the rectifier plate 220.

[0051] According to the present embodiment described above, cooling air that rises along a bubble blown out from the cooling section 104 is sucked by the rectification section 205. By providing the rectifier plate 220, the flow of the cooling air is rectified to some extent, that is, the flow turbulence of the cooling air is reduced, but by sucking the cooling air on the downstream side thereof, the flow turbulence of the cooling air is further reduced.

[0052] Next, a modification related to the second embodiment will be described.

[0053] Figure 6 is a cross-sectional view that enlarges and illustrates the rectification section 205 of the film forming apparatus 200 related to the modification of the second embodiment and its periphery. Figure 6 Corresponding to Figure 5 In the present modification, the suction ring 130 is arranged in the space 250d between the rectifier plate located radially on the outermost side and the cooling section main body 104a. The suction ring 130 of the present modification is configured such that the labyrinth section 140, the baffle 138, and the smoothing flow path 146 are arranged in this order from below in the housing 134. The annular suction port 134b is formed in the inner wall 134e of the housing 134 and directly connects to the communication hole 220a formed in the rectifier plate 220 located radially on the outermost side. According to the present modification, the same effects as the second embodiment can be achieved.

[0054] (Third Embodiment)

[0055] In the third embodiment, as in the second embodiment, a case where the film forming apparatus is provided with a rectifier plate will be described. Hereinafter, the description will be centered on the points of difference from the second embodiment.

[0056] Figure 7 is a cross-sectional view that enlarges and illustrates the rectification section 305 of the film forming apparatus 300 related to the third embodiment and its periphery. Hereinafter, the description will be centered on the points of difference from the film forming apparatus 200 related to the second embodiment.

[0057] The film forming apparatus 300 is provided with the mold 102, the cooling section 104, the rectifying section 305, the pair of guide sections 106, the traction machine 108, and the winding machine 110. The pair of guide sections 106, the traction machine 108, and the winding machine 110 are omitted from illustration.

[0058] The rectifying section 305 includes at least one (in this example, a plurality of) rectifying plates 220 and at least one (in this example, a plurality of) communication passages 104e that constitute a suction section. The plurality of communication passages 104e each extend through the upper wall 104d of the supply flow path 104b in the vertical direction, and each of the plurality of spaces 250b to 250d partitioned by the rectifying plates 220 is in communication with the supply flow path 104b of the cooling section 104. In this example, the plurality of communication passages 104e extend linearly in the vertical direction. In other words, the plurality of communication passages 104e extend linearly, and the direction of extension of the communication passage 104e is orthogonal to the direction of extension of the supply flow path 104b.

[0059] Figure 8 (a) of (b) in FIG. 10, Figure 8 (b) is a plan view showing an example of the communication passage 104e. In Figure 8 In the example of (a) in FIG. 10, the communication passage 104e is formed in a groove shape extending in the circumferential direction when viewed from above. In the example of (a) in FIG. 11, Figure 8 In the example of (a) in FIG. 10, the communication passage 104e is a circular hole when viewed from above.

[0060] The plurality of spaces 250b to 250d can each be in communication via one communication passage 104e as shown in (a) in FIG. 10, or can be in communication via a plurality of communication passages 104e as shown in (b) in FIG. 11. Figure 8 Figure 8

[0061] If the flow rate of the cooling air flowing through the supply flow path 104b becomes high, the pressure of the supply flow path 104b decreases, and a pressure difference is generated between the one end side of the communication passage 104e, that is, the supply flow path 104b, and the other end side, that is, the spaces 250b to 250d. As a result, the air in the plurality of spaces 250b to 250d is sucked to the supply flow path 104b side via the communication passage 104e, and the plurality of spaces 250b to 250d become under pressure, and the cooling air blown out from the cooling section 104 is sucked into the plurality of spaces 250b to 250d.

[0062] In addition, if the diameter of the communication passage 104e becomes too large, the cooling air can flow from the supply flow path 104b into the cooling section 104. Therefore, the communication passage 104e can be formed to be a size such that the cooling air does not flow from the supply flow path 104b into the communication passage 104e, based on experiments, simulations, or the like.

[0063] ​​Also, it can be considered that if the flow rate of the cooling air in the supply flow path 104b is increased, the cooling air becomes difficult to flow from the supply flow path 104b into the communication path 104e. Also, in order to obtain a desired pressure difference, the flow rate of the cooling air flowing through the supply flow path 104b needs to be a certain degree or more. Therefore, as long as the supply flow path 104b is formed to have a flow path area (i.e., height) that enables the desired flow rate, it is acceptable.

[0064] According to the present embodiment described above, the same effects as the second embodiment can be exerted.

[0065] Next, a modification related to the third embodiment will be described.

[0066] Figure 9 is a cross-sectional view that enlarges and illustrates the straightening portion 305 of the film forming apparatus 300 and the vicinity thereof according to the modification of the third embodiment. Figure 9 Corresponding to Figure 7 In the present modification, the plurality of communication paths 104e extend in a straight line, and the angle a formed by the extension direction D1 of the supply flow path 104b and the extension direction D2 of the communication path 104e is greater than 90°. According to the present modification, it is possible to suppress the cooling air flowing through the supply flow path 104b toward the radial inner side of the blow-out portion 104c from flowing into the communication path 104e.

[0067] Figure 10 is a view that illustrates the vicinity of the discharge port 102a of the mold 102 of the film forming apparatus 300 according to another modification of the third embodiment. Figure 10 Corresponding to Figure 7 In the present modification, the plurality of communication paths 104e are formed in a straight line in the vertical direction, and the communication paths 104e are formed to be wider toward the upper side. According to the present modification, the cooling air becomes difficult to flow from the supply flow path 104b into the communication path 104e, and becomes easy to flow from the spaces 250b to 250d into the communication path 104e.

[0068] In addition, it is also possible to combine the modification of Figure 9 and the modification of Figure 10 . That is, the communication path 104e can be formed to be wider toward the upper side, and the angle a formed by the extension direction of the communication path 104e and the extension direction of the supply flow path 104b is greater than 90°.

[0069] Next, a modification common to the first to third embodiments will be described.

[0070] In the embodiments, a so-called round mold in which the discharge port 102a of the mold 102 is circular has been described, but it is not limited thereto. At least a part of the technical idea of the embodiments can also be applied to a so-called T-shaped mold in which the discharge port is straight.

[0071] According to the embodiments, the present application is described using specific words, but the embodiments only show one side of the principles and applications of the present application, and the embodiments can have various modifications and changes in configuration within the scope of the idea of the present application defined by the scope of the claims.

[0072] Industrial applicability

[0073] The present application relates to a film molding apparatus.

[0074] Symbol explanation

[0075] 100, 200, 300 - film molding apparatus, 102 - mold, 102a - discharge port, 104 - cooling section, 104a - cooling section main body, 104b - supply flow path, 104c - blow-out section, 104e - communication path, 105 - rectifying section, 220 - rectifying plate.

Claims

1. A film molding apparatus comprising: a cooling section that cools a molding material discharged from a mold; and a rectifying section that rectifies cooling air blown from the cooling section, wherein the rectifying section includes a suction section that suctions the cooling air, the cooling section cools the molding material discharged from the mold in a cylindrical shape, the rectifying section has a plurality of rectifying plates arranged on a radial outer side of the molding material along the molding material, and the suction section suctions the cooling air rising along the molding material to spaces divided by the plurality of rectifying plates along the rectifying plates.

2. The film molding apparatus according to claim 1, wherein the rectifying plates are arranged in a concentric circular shape, and each space divided by the plurality of rectifying plates is communicated.

3. The film molding apparatus according to claim 1, wherein the cooling section includes a blowing section that blows the cooling air to the molding material and a supply flow path that supplies the cooling air to the blowing section, and the suction section includes a communication path that communicates the spaces divided by the rectifying plates with the supply flow path.

4. The film molding apparatus according to claim 3, wherein the communication path is configured such that the cooling air in the spaces divided by the rectifying plates flows into the communication path.

5. The film molding apparatus according to any one of claims 1 to 4, wherein the rectifying section includes a suction ring that configures the suction section and at least one suction pump, and the suction ring is arranged above the cooling section. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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