Heating device and film stretching device

Abstract

To improve the energy efficiency of heating devices. [Solution] The heating device 100 for heating the conveyed film F comprises a main body 10 having multiple heating chambers 11 defined inside, provided in the direction of conveyance of the film F; an exhaust passage 30 extending along the conveyance direction for discharging a portion of the high-temperature air in each heating chamber 11; an air supply passage 40 extending along the conveyance direction for supplying outside air into each heating chamber 11; and a heat exchange section 50 extending along the conveyance direction and having a contact surface 51 where the exhaust passage 30 and the air supply passage 40 come into contact, and which heats the outside air in the air supply passage 40 with the high-temperature air in the exhaust passage 30.

Description

Technical Field

[0001] The present invention relates to a heating device and a film stretching device.

Background Art

[0002] Patent Document 1 discloses a film manufacturing transverse stretching machine (film stretching device) that grips both end portions in the width direction of a resin film passing through an oven with clips, heats the film with hot air, and stretches the resin film in the lateral direction by expanding the dimensions between the clips.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a film stretching device is provided with a heating device that reheats the hot air used for stretching the film and circulates it to stretch the film again. In such a heating device, in order to maintain the cleanliness of the circulating air, a part of the hot air is discharged to the outside and replaced with normal-temperature air supplied from the outside. Therefore, energy loss is generated by discharging high-temperature air.

[0005] The present invention has been made in view of the above problems, and an object thereof is to improve the energy efficiency of the heating device.

Means for Solving the Problems

[0006] According to one aspect of the present invention, a heating device for heating a conveyed film comprises: a main body provided in a plurality in the direction of conveyance of the film and having heating chambers defined inside; an exhaust passage extending along the conveyance direction and discharging a portion of the high-temperature air in each of the heating chambers; an air supply passage extending along the conveyance direction and supplying outside air to each of the heating chambers; and a heat exchange section extending along the conveyance direction and having a contact surface in which the exhaust passage and the air supply passage come into contact, and which heats the outside air in the air supply passage with the high-temperature air in the exhaust passage. [Effects of the Invention]

[0007] In this embodiment, a heat exchange section is provided that extends along the film transport direction and has a contact surface where the exhaust passage and the supply passage abut, and heats the outside air in the supply passage with the high-temperature air in the exhaust passage. As a result, heat is transferred from the high-temperature air in the exhaust passage to the low-temperature air in the supply passage via the contact surface. This heats the air in the supply passage and raises its temperature. Therefore, the thermal energy of the discharged high-temperature air can be used to raise the temperature of the supplied air, thereby improving the energy efficiency of the heating device. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a plan view of a film stretching apparatus to which a heating device according to an embodiment of the present invention is applied. [Figure 2] Figure 2 is a front view of the heating device. [Figure 3] Figure 3 is a plan view of Figure 2. [Figure 4] Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. [Figure 5] Figure 5 is a view from the direction of arrow V in Figure 3. [Figure 6] Figure 6 is a cross-sectional view showing a portion of the heat exchange section in the longitudinal direction. [Figure 7A] Figure 7A is a diagram illustrating a first modified example of the heat exchange section. [Figure 7B]Figure 7B is a cross-sectional view of the VIIB-VIIB section in Figure 7A. [Figure 8A] Figure 8A is a diagram illustrating a second modified example of the heat exchange section. [Figure 8B] Figure 8B is a cross-sectional view of the VIIIB-VIIIB section in Figure 8A. [Modes for carrying out the invention]

[0009] Hereinafter, a heating device 100 according to an embodiment of the present invention will be described with reference to the drawings. Note that, for the sake of clarity, the scale of each component in the drawings has been appropriately changed and is not necessarily strictly accurate. Furthermore, for multiple identical components, only some parts may be denoted by reference numerals, while others may be omitted.

[0010] First, with reference to Figure 1, the overall configuration of the film stretching apparatus (hereinafter simply referred to as the "stretching apparatus") 1 to which the heating device 100 is applied will be described. Figure 1 is a diagram of the configuration of the stretching apparatus 1.

[0011] As shown in Figure 1, the heating device 100 is used in the stretching device 1, which stretches the film F (see Figure 4) to be stretched while transporting it. In Figure 1, the heating device 100 is simplified and shown with a dashed line.

[0012] The stretching device 1 is a transverse stretching device that stretches the film F in a transverse direction perpendicular to the longitudinal direction (hereinafter also referred to as the "width direction") while transporting the film F in one direction from the inlet side (left side in Figure 1) to the outlet side (right side in Figure 1). In the following description, "right side" refers to the right side when looking from the inlet side to the outlet side (lower side in Figure 1), and "left side" refers to the left side when looking from the inlet side to the outlet side (upper side in Figure 1).

[0013] The stretching device 1 includes a pair of rail devices 7L and 7R that define an endless circulation path and are arranged on both the left and right sides of the film F, a plurality of clip units 3 that travel along the circulation path of the pair of rail devices 7L and 7R and grip the film F, and a heating device 100 that heats the conveyed film F.

[0014] The pair of rail devices 7L and 7R are each constituted by a reference rail 8 that defines a circulation path for circulating the clip unit 3.

[0015] Since it is a known configuration, detailed illustration and description are omitted. The reference rail 8 is formed by a plurality of rail units that are rotatably connected. By rotatably connecting adjacent rail units to each other, the arrangement of the plurality of rail units can be changed to form a desired circulation path.

[0016] Since the configuration of the clip unit 3 can adopt a known configuration, detailed illustration and description are omitted. The clip units 3 adjacent on the circulation path are connected by a link mechanism (not shown). That is, the plurality of clip units 3 are connected in an endless manner by the link mechanism.

[0017] The plurality of clip units 3 are run along the circulation path by a drive mechanism (not shown). Specifically, the plurality of clip units 3 are each guided by the reference rail 8 of the pair of rail devices 7L and 7R and move in a loop. The clip unit 3 moves in a clockwise direction in the right rail device 7R in FIG. 1 and moves counterclockwise in the left rail device 7L. In the pair of rail devices 7L and 7R, the same number of clip units 3 move in a circular motion with respect to each other.

[0018] Since the drive mechanism can adopt a known configuration, a detailed description thereof will be omitted. As an example, the drive mechanism includes a pair of inlet side sprockets 5L and 5R provided on the inlet side for supplying the film F, a pair of outlet side sprockets 6L and 6R provided on the outlet side for sending out the stretched film F, and an electric motor for driving the pair of outlet side sprockets 6L and 6R.

[0019] By repeating the sequential engagement and disengagement of each clip unit 3 with respect to the rotating inlet side sprockets 5L, 5R and outlet side sprockets 6L, 6R, a force for traveling along the circuit path is applied to each clip unit 3.

[0020] The stretching device 1 has a lateral adjustment mechanism (not shown) for adjusting the distance between the left and right rail devices 7L and 7R. The lateral adjustment mechanism is, for example, a linear motion mechanism having a screw mechanism to which an electric motor or a manual handle is connected, and moves the rail unit in the left - right direction. Since the lateral adjustment mechanism can adopt a known configuration, its illustration and detailed description will be omitted.

[0021] The drive device for running the clip unit 3 is controlled in operation by a controller (not shown).

[0022] At the inlet where the film F is taken in, both side edges of the film F are gripped by the clip units 3 traveling along the left and right circuit paths. The film F gripped by the clip unit 3 is conveyed along the conveyance direction as the clip unit 3 moves. The conveyed film F is released from the grip of the clip unit 3 at the outlet side and moves straight ahead. In this way, the film F gripped by the clip unit 3 is conveyed from the inlet side toward the outlet side.

[0023] The film F is transported in one direction along a predetermined plane. The film transport surface is, for example, a virtual plane parallel to the horizontal plane. In the following explanation, terms such as perpendicular or parallel to the film F do not mean perpendicular or parallel to the film F that is actually being transported, but rather perpendicular or parallel to the film transport surface (in other words, perpendicular or parallel to the film F that is ideally transported so as to be parallel to the film transport surface).

[0024] In the stretching device 1, the area where the left and right rail devices 7L and 7R face each other is configured as the film transport area TA. In the film transport area TA, the preheating zone Za, the stretching zone Zb, and the heat treatment zone Zc are arranged (assigned) in order from the inlet side to the outlet side of the stretching device 1.

[0025] In the preheating zone Za, the distance between the left and right circulation paths is set to correspond to the initial width of the film F, and the left and right circulation paths are arranged parallel to each other throughout the entire area. Therefore, in the preheating zone Za, the film F is not stretched; only the process of preheating the film F to a temperature at which it can be stretched is performed.

[0026] In the stretching zone Zb, the distance between the left and right circulation paths gradually increases as you move from the preheating zone Za towards the heat treatment zone Zc. In other words, in the stretching zone Zb, the left and right circulation paths are arranged in a flared shape, with the distance between them increasing from the inlet side to the outlet side. Therefore, in the stretching zone Zb, the lateral distance between the clip units 3 gradually increases. Consequently, in the stretching zone Zb, the film F undergoes stretching in the width direction (lateral stretching).

[0027] After passing through the stretching zone Zb and being stretched laterally, the film F then enters the heat treatment zone Zc. In the heat treatment zone Zc, the distance between the left and right circulation paths is set to correspond to the width of the stretched film F, and the left and right circulation paths are arranged parallel to each other throughout the entire zone. Therefore, in the heat treatment zone Zc, no lateral stretching of the film F takes place; only heat treatment such as temperature adjustment is performed.

[0028] Next, the configuration of the heating device 100 will be described with reference to Figures 2 to 6. Figure 2 is a front view of the heating device 100. Figure 3 is a plan view of Figure 2. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. Figure 5 is a view taken along arrow V in Figure 3. Figure 6 is a cross-sectional view showing a portion of the heat exchange section 50 in the longitudinal direction.

[0029] As shown in Figures 2 and 3, the heating device 100 heats the film F that is transported by the stretching device 1. The heating device 100 comprises a main body 10, a circulation passage 20, an exhaust passage 30 as an inner circumferential passage, an air supply passage 40 as an outer circumferential passage, a heat exchange section 50, and a heat insulating member 60.

[0030] Multiple main body sections 10 are arranged in a row in the direction of film F transport. As shown in Figure 4, a heating chamber 11 is defined inside the main body section 10. The main body section 10 has a passage opening (not shown) that opens into the heating chamber 11 and allows the film F to pass through.

[0031] The heating chamber 11 is defined within the main body 10 as a space through which the film F passes. Inside the heating chamber 11, the film F is heated by high-temperature air. A branching passage 24, which supplies high-temperature air heated by a heater 22 (described later), is inserted into the heating chamber 11 from the side. The heating chamber 11 houses a pair of spraying units 26 that spray the high-temperature air supplied via the branching passage 24 onto the film F.

[0032] The circulation passage 20 heats most of the high-temperature air heated in the heating chamber 11 over the film F, as well as outside air supplied from the air supply passage 40 (described later), and circulates it back to the heating chamber 11. The circulation passage 20 includes a confluence passage 21, a heater 22 as a heating unit, a circulation fan 23, a branching passage 24, an opening adjustment mechanism 25, and a spraying unit 26.

[0033] The confluence passage 21 is defined at the top of the heating chamber 11. High-temperature air that has risen from the heating chamber 11 by forced convection generated by the circulation fan 23 is guided into the confluence passage 21. Outside air supplied from the supply air passage 40 is also guided into the confluence passage 21. The confluence passage 21 combines the high-temperature air discharged upward from the heating chamber 11 with the outside air supplied from the supply air passage 40. The air that has merged in the confluence passage 21 rises further and is guided to the heater 22.

[0034] The heater 22 reheats the air introduced from the confluence passage 21. In the confluence passage 21, the outside air supplied from the air supply passage 40 merges with the high-temperature air discharged from the heating chamber 11, causing the air temperature to decrease. Therefore, the heater 22 reheats the air in order to spray high-temperature air again from the spraying section 26 in the heating chamber 11 towards the film F.

[0035] The circulation fan 23 generates a flow that guides the high-temperature air, reheated by the heater 22, back into the heating chamber 11.

[0036] The branching passage 24 splits the high-temperature air guided by the circulation fan 23 into two, each leading to a pair of spray nozzles 26. The high-temperature air guided into each branching passage 24 is then led to the spray nozzles 26 connected to each of them.

[0037] The opening degree adjustment mechanism 25 is provided upstream of each of the pair of branch passages 24. The opening degree adjustment mechanism 25 adjusts the opening degree (flow path area) of the communication section to each of the branch passages 24 so that the high-temperature air introduced by the circulation fan 23 is branched and introduced into the pair of branch passages 24. The opening degree of the opening degree adjustment mechanism 25 is adjusted manually.

[0038] The spraying units 26 are positioned above and below the film F within the heating chamber 11. That is, the space between the pair of spraying units 26 is the space through which the film F, being transported in the transport direction, passes. The spraying units 26 spray high-temperature air onto the film F from above and below.

[0039] As shown in Figures 2 and 3, the exhaust passage 30 extends along the conveying direction. The exhaust passage 30 discharges a portion of the high-temperature air generated by heating the film F in the heating chamber 11 to the outside. Specifically, the exhaust passage 30 discharges the remaining air after deducting the portion that is guided from the heating chamber 11 to the circulation passage 20. The exhaust passage 30 includes a main passage 31, a branch passage 32, an exhaust fan 33, and a spiral projection 34 as a first projection (see Figure 6).

[0040] The main passage 31 guides the high-temperature air discharged from the heating chamber 11 via each of the branch passages 32 along the transport direction in order to discharge it to the outside. The main passage 31 constitutes the inner circumferential passage of the double-pipe structure heat exchange section 50, which will be described later. The main passage 31 is provided on the inner circumference of the main passage 41 of the supply air passage 40.

[0041] As shown in Figure 4, the branch passage 32 is connected to the upper surface of the heating chamber 11. The branch passage 32 directs a portion of the high-temperature air in the heating chamber 11 directly to the main passage 31.

[0042] As shown in Figures 2 and 3, the exhaust fan 33 is provided at the downstream end of the main passage 31 in the conveying direction. The exhaust fan 33 may also be provided at the upstream end of the main passage 31 in the conveying direction, or in the middle section. The exhaust fan 33 generates a flow that discharges the high-temperature air introduced through the main passage 31 to the outside.

[0043] As shown in Figure 6, the spiral projection 34 protrudes outward from the outer wall portion 30a of the exhaust passage 30 along the conveying direction, increasing the heat exchange area. The spiral projection 34 is provided along the extending direction of the exhaust passage 30 and the supply air passage 40. The spiral projection 34 is provided along the direction of airflow within the exhaust passage 30 and the supply air passage 40. Specifically, the spiral projection 34 protrudes spirally from the outer wall portion 30a of the exhaust passage 30 outward.

[0044] As shown in Figures 2 and 3, the air supply passage 40 extends along the conveying direction. The air supply passage 40 supplies outside air into each heating chamber 11. The air supply passage 40 has a main passage 41, a plurality of branch passages 42, and an air supply fan 43.

[0045] The main passage 41 guides outside air to be supplied to the heating chamber 11 via each of the branch passages 42. The main passage 41 constitutes the outer periphery passage of the double-pipe heat exchange section 50, which will be described later. The main passage 41 is provided on the outer periphery of the main passage 31 of the exhaust passage 30. The air in the main passage 41 flows in opposition to the airflow in the main passage 31 of the exhaust passage 30.

[0046] As shown in Figure 4, the branch passage 42 is connected to the side of the merging passage 21. The branch passage 42 guides the air supplied from the main passage 41 into the merging passage 21.

[0047] As shown in Figures 2 and 3, the supply air fan 43 is installed near the downstream end in the transport direction of the main passage 41. The supply air fan 43 draws outside air into the main passage 41 and generates an airflow that supplies it to the confluence passage 21 via the branch passage 42.

[0048] The heat exchange section 50 extends along the conveying direction. The heat exchange section 50 heats the outside air in the supply air passage 40 with the high-temperature air in the exhaust passage 30. The heat exchange section 50 has a double-pipe structure in which the exhaust passage 30 is provided on the inner circumference side and the supply air passage 40 is provided on the outer circumference of the exhaust passage 30. The heat exchange section 50 has a contact surface 51 in which the exhaust passage 30 and the supply air passage 40 come into contact.

[0049] As shown in Figure 6, in the double-pipe heat exchange section 50, the contact surface 51 is formed by the outer wall portion 30a of the exhaust passage 30 provided on the inner circumference side. The contact surface 51 transfers heat from the high-temperature air in the exhaust passage 30 to the outside air in the supply passage 40.

[0050] As described above, the heating device 100 comprises a main body 10 provided in multiple locations in the direction of film F transport, with heating chambers 11 defined inside; an exhaust passage 30 extending along the transport direction and discharging a portion of the high-temperature air in each heating chamber 11; an air supply passage 40 extending along the transport direction and supplying outside air into each heating chamber 11; and a heat exchange section 50 extending along the transport direction and having a contact surface 51 where the exhaust passage 30 and the air supply passage 40 come into contact, and which heats the outside air in the air supply passage 40 with the high-temperature air in the exhaust passage 30.

[0051] Thus, a heat exchange section 50 is provided that extends along the transport direction of the film F and has a contact surface 51 that comes into contact with the exhaust passage 30 and the supply passage 40, and heats the outside air in the supply passage 40 with the high-temperature air in the exhaust passage 30. As a result, heat is transferred from the high-temperature air in the exhaust passage 30 to the low-temperature air in the supply passage 40 via the contact surface 51. This heats the air in the supply passage 40 and raises its temperature.

[0052] Therefore, by utilizing the thermal energy of the discharged high-temperature air, the temperature of the supplied air can be increased, thus reducing the energy required to heat the air with the heater 22. Consequently, the energy efficiency of the heating device 100 can be improved.

[0053] Furthermore, since the heat exchange section 50 is provided along the transport direction of the film F, a contact surface 51 can be formed over a long section spanning the entire length of the stretching device 1. Therefore, the heat exchange area can be increased, and more thermal energy can be recovered from the discharged high-temperature air into the supplied outside air.

[0054] Furthermore, since the heat exchange section 50 has a double-pipe structure with an exhaust passage 30 on the inner circumference and an air supply passage 40 on the outer circumference of the exhaust passage 30, there is no need to separately provide a complex heat exchanger such as a heat pipe type, and the heat exchange section 50 can be constructed with a simple structure.

[0055] Furthermore, since spiral projections 34 are provided that protrude from the outer wall portion 30a of the exhaust passage 30 toward the outer periphery into the supply air passage 40 along the conveying direction, the heat exchange area at the contact surface 51 can be increased. In addition, the provision of spiral projections 34 disrupts the airflow within the supply air passage 40, thereby improving the heat exchange efficiency.

[0056] The heat insulating member 60 covers the outer perimeter of the exhaust passage 30, suppressing heat exchange with the outside. By providing the heat insulating member 60 on the outer perimeter of the supply air passage 40, it is possible to suppress the discharge of heat energy recovered from the high-temperature air in the exhaust passage 30 into the outside air in the supply air passage 40.

[0057] Next, the first and second modified examples of the heat exchange section 50 will be described with reference to Figures 7A to 8B. Figure 7A is a configuration diagram illustrating the first modified example of the heat exchange section 50. Figure 7B is a cross-sectional view taken along the line VIIB-VIIB in Figure 7A. Figure 8A is a configuration diagram illustrating the second modified example of the heat exchange section 50. Figure 8B is a cross-sectional view taken along the line VIIIB-VIIIB in Figure 8A.

[0058] As shown in the first modified example in Figures 7A and 7B, a linear projection 35, which is provided in a straight line along the conveying direction rather than in a spiral shape, may be provided as the first projection. This first modified example also produces the same effects as the above embodiment.

[0059] Furthermore, as shown in the second modified example in Figures 8A and 8B, an annular plate 45 may be provided in the air supply passage 40 as a second projection that protrudes inward from the outer wall portion 40a of the air supply passage 40, partially reducing the flow area within the air supply passage 40. The annular plate 45 is formed around the entire circumference of the air supply passage 40. By providing the annular plate 45 in this way, the flow area of ​​the air supply passage 40 at the location where the annular plate 45 is provided can be partially reduced. As a result, the airflow velocity within the air supply passage 40 at the location where the annular plate 45 is provided increases, thereby improving the heat exchange efficiency.

[0060] The effects and advantages of this embodiment will be explained below.

[0061] The heating device 100 for heating the conveyed film F comprises a main body 10 having multiple heating chambers 11 defined inside, provided in the direction of conveyance of the film F; an exhaust passage 30 extending along the conveyance direction for discharging a portion of the high-temperature air in each heating chamber 11; an air supply passage 40 extending along the conveyance direction for supplying outside air into each heating chamber 11; and a heat exchange section 50 extending along the conveyance direction and having a contact surface 51 where the exhaust passage 30 and the air supply passage 40 come into contact, which heats the outside air in the air supply passage 40 with the high-temperature air in the exhaust passage 30.

[0062] Furthermore, the stretching device 1 is equipped with a heating device 100, which heats the conveyed film F while stretching it in at least one of the conveying direction and the width direction.

[0063] According to these configurations, a heat exchange unit 50 is provided that extends along the transport direction of the film F and has a contact surface 51 that comes into contact with the exhaust passage 30 and the supply passage 40, and heats the outside air in the supply passage 40 with the high-temperature air in the exhaust passage 30. As a result, heat is transferred from the high-temperature air in the exhaust passage 30 to the low-temperature air in the supply passage 40 via the contact surface 51. This heats the air in the supply passage 40 and raises its temperature. Therefore, the energy efficiency of the heating device 100 can be improved by utilizing the thermal energy of the discharged high-temperature air to raise the temperature of the supplied air.

[0064] Furthermore, since the heat exchange section 50 is provided along the transport direction of the film F, a contact surface 51 can be formed over a long section spanning the entire length of the stretching device 1. Therefore, the heat exchange area can be increased, and more thermal energy can be recovered from the discharged high-temperature air into the supplied outside air.

[0065] The heat exchange section 50 has a double-pipe structure, comprising an inner circumferential passage provided on the inner circumference and constituting one of the exhaust passage 30 and the supply passage 40, and an outer circumferential passage provided on the outer circumference of the inner circumferential passage and constituting the other of the exhaust passage 30 and the supply passage 40. The inner circumferential passage is the exhaust passage 30, and the outer circumferential passage is the supply passage 40.

[0066] With these configurations, the heat exchange section 50 has a double-pipe structure in which an exhaust passage 30 is provided on the inner circumference and an air supply passage 40 is provided on the outer circumference of the exhaust passage 30. Therefore, there is no need to separately provide a complex heat exchanger such as a heat pipe type, and the heat exchange section 50 can be constructed with a simple structure.

[0067] The heating device 100 further includes an insulating member 60 that covers the outer periphery of the air supply passage 40 to suppress heat exchange with the outside.

[0068] With this configuration, by providing an insulating member 60 on the outer periphery of the air supply passage 40, it is possible to suppress the discharge of heat energy recovered from the high-temperature air in the exhaust passage 30 into the outside air in the air supply passage 40.

[0069] The air supply passage 40 is provided with a first projection that protrudes outward from the outer wall portion 30a of the exhaust passage 30 along the conveying direction, thereby increasing the heat exchange area. The first projection is a spiral projection 34 that protrudes spirally from the outer wall portion 30a of the exhaust passage 30 outward.

[0070] With these configurations, spiral projections 34 are provided that protrude from the outer wall portion 30a of the exhaust passage 30 toward the outer periphery into the supply passage 40, thereby increasing the heat exchange area at the contact surface 51. Furthermore, the presence of the spiral projections 34 disrupts the airflow within the supply passage 40, thereby improving the heat exchange efficiency.

[0071] The air supply passage 40 is provided with a second projection that extends in an annular shape from the outer wall portion 40a of the air supply passage 40 toward the inner circumference along the entire circumference of the air supply passage 40, thereby partially reducing the flow area within the air supply passage 40.

[0072] With this configuration, an annular plate 45 is provided that protrudes in an annular shape from the outer wall portion 40a of the air supply passage 40 toward the inner circumference, so that the flow area of ​​the air supply passage 40 can be partially reduced at the location where the annular plate 45 is provided. As a result, the airflow velocity in the air supply passage 40 increases at the location where the annular plate 45 is provided, and thus the heat exchange efficiency can be improved.

[0073] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0074] For example, in the above embodiment, the stretching device 1 stretches the film F in the transverse direction, but it may also stretch the film F in the longitudinal direction, or it may simultaneously stretch it biaxially in both the longitudinal and transverse directions. That is, the heating device 100 is applied to the stretching device 1 which heats the conveyed film F and stretches it in at least one of the conveying direction and the width direction.

[0075] Furthermore, the above embodiment described a case where the inner circumferential passage is an exhaust passage 30 and the outer circumferential passage is an air supply passage 40. However, the inner circumferential passage may be an air supply passage 40 and the outer circumferential passage may be an exhaust passage 30. [Explanation of Symbols]

[0076] 100 Heating device 1. Stretching device (film stretching device) 10 Main body 11 Heating chamber 30 Exhaust passage (inner circumferential passage) 34 Spiral projection (first projection) 35 Linear protrusion (first protrusion) 40. Air supply passage (perimeter passage) 45 Annular plate (second projection) 50 Heat exchange section 51 Contact surface 60 Insulation material F Film

Claims

1. A heating device for heating a film being transported, Multiple main body sections are provided in the direction of transport of the film, and a heating chamber is defined inside each section. An exhaust passage extending along the transport direction and for discharging a portion of the high-temperature air in each of the heating chambers, An air supply passage extending along the transport direction and supplying outside air to each of the heating chambers, A heat exchange unit extending along the transport direction and having a contact surface in which the exhaust passage and the supply passage come into contact, which heats the outside air in the supply passage with the high-temperature air in the exhaust passage, Equipped with, heating device.

2. A heating device according to claim 1, The heat exchange section has a double-pipe structure comprising an inner circumferential passage provided on the inner circumference and constituting one of the exhaust passage and the supply passage, and an outer circumferential passage provided on the outer circumference of the inner circumferential passage and constituting the other of the exhaust passage and the supply passage. heating device.

3. A heating device according to claim 2, The inner circumferential passage is the exhaust passage, and the outer circumferential passage is the supply passage. heating device.

4. A heating device according to claim 3, The outer perimeter passage is further provided with an insulating member that covers the outer perimeter to suppress heat exchange with the outside. heating device.

5. A heating device according to claim 4, The outer peripheral passage is provided with a first projection that extends outward from the outer wall of the inner peripheral passage along the conveying direction, thereby increasing the heat exchange area. heating device.

6. A heating device according to claim 5, The first projection is a spiral projection that protrudes spirally from the outer wall toward the outer circumference. heating device.

7. A heating device according to claim 4, The outer perimeter passage is provided with a second projection that extends in an annular shape from the outer wall of the outer perimeter passage toward the inner circumference, extending along the entire circumference of the outer perimeter passage, thereby partially reducing the flow area within the outer perimeter passage. heating device.

8. A heating device according to any one of claims 1 to 7, wherein the conveyed film is heated and stretched in at least one of the conveying direction and the width direction, Film stretching machine.

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