JP2007152816A - Apparatus and method for processing sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for processing a sheet in an apparatus heating, cooling and drying the sheet by air coming from air blowing openings which are not continuous along the direction of a sheet width, which is capable of obtaining the sheet having even properties along the direction of the sheet width by effectively decreasing the unevenness of heat transfer along the direction of the sheet width. <P>SOLUTION: In the apparatus heating, cooling and drying the sheet being unidirectionally transferred by air coming from the air blowing openings which are not continuous along the direction of the sheet width, the positions of the air blowing openings of each nozzle are shifted in the direction of the sheet width. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a processing apparatus and a sheet processing method for heating or cooling and drying a sheet such as a thermoplastic resin film.

  An apparatus for performing stretching or heat treatment when producing a thermoplastic film is called a tenter oven. This tenter oven will be described as an example. Generally, a plurality of zones are connected in the longitudinal direction of the film, and the film is preheated, stretched and heated while maintaining the predetermined temperature in each zone. Processing such as setting and cooling is performed. The zone is divided into one or a plurality of chambers in the longitudinal direction of the film, and the temperature can be set in each chamber.

  An example of a general tenter oven is shown in FIG. The film traveling direction is from left to right in the figure. The nozzle 4 is provided with an air jet port toward the film 3. In the case where the air outlet is a slit-like shape that is continuously opened in the film width direction, called a slit nozzle, ideally air is blown onto the film in the film width direction. Does not happen. However, in actuality, a slit nozzle is likely to generate an MD (abbreviation of machine direction) flow in which air flows in the longitudinal direction of the film beyond the partition of the chamber, and the nozzle flow (the flow of air blown from the air outlet) also Since it is unstable, uneven heat transfer and uneven temperature occur. Therefore, a hole nozzle that is excellent in terms of MD flow reduction, nozzle flow stability, and high heat transfer is employed. With a hole nozzle, the air ejection port provided at the tip of the nozzle is a perforated plate.

  An example of a general hole nozzle is shown in FIG. This figure is a schematic view of the hole nozzle as seen from the film. In the drawing, the air outlets are positioned in two rows with respect to one nozzle, and the positions of the air outlets are alternately arranged in each row. This is called a two-row staggered arrangement. The shape of the air outlet is a round hole. In addition, the shape and position of the air outlet are the same for each nozzle.

  Here, it can be seen from FIG. 4 that when the hole nozzle is employed, the air outlet is discontinuous in the film width direction. Therefore, unevenness of the heat transfer coefficient occurs in the film width direction on the film surface, and as a result, the characteristics in the film width direction become non-uniform.

In order to solve this problem, in FIG. 4, the positions of the air ejection ports are already arranged in two rows in a staggered arrangement so that the heat transfer unevenness is made smaller than in the case of one row. In addition, as shown in FIG. 5, a method of gradually shifting the position of the air ejection port (for example, see Patent Document 1) or changing the amount of air ejection depending on the location (for example, see Patent Document 2) has been proposed.
JP 7-329153 A Japanese Patent Laid-Open No. 5-96619

  However, even if the air outlets are arranged in a staggered manner, the unevenness of the heat transfer coefficient in the film width direction is reduced, but it is not eliminated, and the method of gradually shifting the position of the air outlets as in Patent Document 1 Then, depending on the location, there is a problem that the position of the air jet port is deviated and the unevenness of the heat transfer coefficient may increase. Further, in the method of changing the air ejection amount from a part of the air ejection ports as in Patent Document 2 to reduce the heat transfer unevenness on the film surface, if the adjustment is wrong, the heat transfer unevenness is conversely large. There is a problem of becoming.

  An object of the present invention is to improve the drawbacks of the conventional technology and to effectively reduce the unevenness of the heat transfer coefficient in the sheet width direction, thereby enabling uniform sheet width direction characteristics and a sheet processing apparatus and sheet. It is in providing the processing method of.

In order to solve this problem, the following means are adopted. That is, the sheet processing apparatus of the present invention is a sheet processing apparatus that heats, cools, or dries a sheet conveyed in a certain direction by air from a plurality of nozzles provided in the conveyance direction. Having a plurality of air outlets,
Sheet width of the air outlet provided to the nth nozzle from the upstream in the sheet conveying direction (n is an integer not less than a + 1 and not more than the number of nozzles, a is an arbitrary integer not less than 1 and not more than the number of nozzles) This is a sheet processing apparatus whose position in the direction is determined by the following procedure. The sheet processing method of the present invention is a sheet processing method using the sheet processing apparatus.
(1) With the nozzles in the a-th to n-th range, the average value in the sheet conveyance direction of the heat transfer coefficient of the sheet surface,
(2) In order to minimize the unevenness in the sheet width direction of the average value,
(3) The position in the sheet width direction of the air outlet provided to the nth nozzle is obtained,
(4) The position in the sheet width direction of the air outlet of the nth nozzle is determined within a range of ± 10 mm in the sheet width direction from that position.

  According to the present invention, it is possible to obtain a sheet having excellent physical property uniformity in the sheet width direction.

  The sheet referred to in the present invention refers to a thin plate such as a thermoplastic resin film or cloth. The feature of the sheet processing apparatus of this embodiment is that the position of an air outlet of a nozzle is determined so that the heat transfer unevenness in the sheet width direction is reduced based on the heat transfer distribution on the sheet surface upstream of the position. There is.

  Hereinafter, an example in which the best embodiment of the present invention is applied to a tenter oven will be described with reference to the drawings. In the tenter oven, means for preheating, stretching, heat treatment, and cooling are generally provided, but the presence of these means is arbitrary as a processing apparatus in this embodiment. FIG. 1 is a schematic view of a nozzle as viewed from a sheet in the processing apparatus of this embodiment. The nozzle according to the present invention is a nozzle including a perforated plate having a large number of air ejection ports, and is generally called a hole nozzle. In the drawing, the sheet conveying direction is from left to right. The conveyance direction in this embodiment refers to the direction from the inlet to the outlet of the processing apparatus. Further, the sheet width direction represents a direction in which the distance between both ends of the sheet is the shortest. In FIG. 1, with respect to each nozzle, the position of the air outlet is shifted in the sheet width direction in units of nozzles. Here, the position of the air outlet may be shifted in the sheet width direction by any nozzle, or a single nozzle or a plurality of nozzles. In addition, the air outlets 5 are round and have a staggered arrangement of two rows per nozzle, but the shape and position of the air outlets are not limited to this.

  The principle of reducing the heat transfer unevenness in the sheet width direction by the sheet processing apparatus of the present invention will be described with reference to FIGS. In FIG. 2, the position of the air ejection port is the same for every nozzle. In each figure, the leftmost nozzle is the first, and the second, right, second, third,. The heat transfer coefficient of the sheet surface is the highest immediately below the air outlet, and the value decreases as the distance from the position increases. Therefore, when the sheet passes through the locations indicated by arrows A and B in FIG. 2, the average value of the heat transfer coefficient on the sheet surface is different. However, as shown in FIG. 1, when the sheet passes through the locations indicated by the arrows A and B by shifting the position of the air ejection port, the average value of the heat transfer coefficient of the sheet surface in the sheet conveyance direction is the same in the sheet width direction. Or close.

  This will be described in more detail as follows.

  First, consider the a-th and subsequent nozzles. Here, the a-th nozzle is any one of the first nozzle to the (nozzle number-1) -th nozzle. In determining the position in the sheet width direction of the air outlet of a certain nozzle (hereinafter referred to as the nth nozzle) after the (a + 1) th, it is determined by the following procedure.

First, an average value in the sheet conveying direction of the heat transfer coefficient of the sheet surface is obtained in the range of the a-th to n-th nozzles. Then, the unevenness in the sheet width direction of the average value is obtained. Here, the unevenness in the sheet width direction is one of the following values (1) to (5), and can be appropriately selected depending on what kind of unevenness is desired to be eliminated.
(1) The standard deviation in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction.
(2) The maximum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction—the minimum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction.
(3) (Maximum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction−Minimum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet width direction) / Sheet in the sheet conveyance direction average value of the heat transfer coefficient Maximum value in the width direction.
(4) (Maximum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet width direction−Minimum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet width direction) / Sheet in the sheet transport direction average value of the heat transfer coefficient Minimum value in the width direction.
(5) (Maximum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction−Minimum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet width direction) / Sheet in the sheet conveyance direction average value of the heat transfer coefficient Average value in the width direction.

  Next, the position of the air outlet of the nth nozzle is shifted in the sheet width direction. Then, the average value in the sheet conveyance direction of the heat transfer coefficient of the sheet surface is obtained again with the nozzles in the a-th to n-th range, and the unevenness in the sheet width direction of the average value is further obtained.

  The above procedure is repeated, and the position in the sheet width direction of the air outlet where the unevenness of the average value of the heat transfer coefficient in the sheet conveyance direction is minimized is determined as the position of the air outlet at the nth nozzle. By doing so, it is possible to minimize the unevenness in the sheet width direction of the heat transfer coefficient of the sheet surface for the sheet passing through the nth nozzle.

  Here, if the amount of shifting the air ejection port is set so that the unevenness of the heat transfer coefficient is minimized, when there are many nozzles, the pattern of the amount of displacement becomes too large, making it difficult to create the nozzles. Therefore, for example, if the amount of deviation is set to 10 mm units such as 10 mm, 20 mm, 30 mm,..., The number of nozzle patterns to be created can be reduced. However, if the amount of deviation is in units of 10 mm, it will deviate from the optimum amount of deviation within a range of ± 5 mm. Considering the labor and accuracy of nozzle creation, the amount deviating from the optimum shift amount is preferably about ± 10 mm.

It is preferable to perform the above operation for a plurality of nozzles after the (a + 1) th, since it is possible to further reduce unevenness in the sheet width direction of the heat transfer coefficient of the sheet surface after the ath nozzle. Specifically, a description will be given of the case where it is applied to the n _1st , n _2nd ,..., Mn _m nozzles after the (a + 1) th nozzle (where m is 1 or more, (the number of nozzles−a). the following arbitrary _{integer. n 1, n 2, ···} , n m are both a + 1 or more, with an integer number of _nozzles, n ₁ <n 2 <··· satisfy _{<n m} any integer.) . First, the above operation is performed for the n _1st nozzle, and then the above operation is performed for the n _2nd nozzle. This sequence, n ₃ th nozzle, n ₄ th nozzle ..., for n _m-th nozzle may do by carrying out the above-described operation.

  More preferably, when the above operation is performed for all the nozzles after the (a + 1) th, unevenness in the sheet width direction of the heat transfer coefficient of the sheet surface after the ath nozzle can be further reduced.

  Most preferably, when the above operation is performed for all the second and subsequent nozzles, unevenness in the sheet width direction of the heat transfer coefficient of the sheet surface can be reduced throughout the tenter oven.

  Moreover, it is preferable that the arrangement | positioning (relative position) of the air jet nozzle in a nozzle is the same arrangement | positioning about all the nozzles in a tenter oven. If the arrangement of the air jets of all the nozzles is the same, it is not necessary to change the arrangement of the air jets individually for each nozzle, which is preferable because the labor for nozzle processing is reduced.

  The present invention will be described based on examples.

  As shown in FIG. 6, in the tenter oven of the tenter oven in the upper half of the sheet, there are six nozzles and a large opening is provided outside the tenter oven. The heat transfer distribution on the sheet surface was calculated by performing fluid analysis using “STAR-CD” manufactured by D-Adapco Japan.

  The above software analyzes the Navier-Stokes equation, which is the equation of motion of fluid, by the finite volume method. Of course, any thermal fluid analysis software other than the above software may be used as long as the same analysis can be performed.

  The distance between the air outlet and the sheet is 180 mm, the pitch between the nozzles is 340 mm, and the air outlet of each nozzle is a round hole with a diameter of 25 mm. Further, as shown in FIG. 7, the relative positions of the air outlets at the respective nozzles are 80 mm in the sheet traveling direction and 100 mm in the sheet width direction. Moreover, the speed of air at the air outlet is 15 m / s.

  In this configuration, with the nozzles from the second row to the sixth row, the position of the air outlet of each nozzle was shifted in the sheet width direction based on the present invention.

  For example, when determining the amount of deviation in the sheet width direction at the second nozzle, first determine the position of the air outlet of the first nozzle in the sheet width direction as a reference, and then In the second nozzle, the position of the air outlet is gradually shifted in the sheet width direction in units of 5 mm or 10 mm from the reference position, and within the range where the first and second nozzles are combined for each deviation amount, Obtain the heat transfer coefficient of the sheet surface. Then, the average value in the sheet conveying direction was obtained, and the position at the deviation amount where the standard deviation in the sheet width direction was the smallest was taken as the position of the air nozzle of the second nozzle. For the third nozzle, the optimal position of the air outlet of the third nozzle was determined in the same manner without changing the position of the air outlet of the second nozzle determined previously. Similarly, the positions of the air outlets were determined for the fourth to sixth nozzles.

  FIG. 8 shows the distribution of the average value in the sheet conveying direction of the heat transfer coefficient of the sheet surface in the range from the first to sixth nozzle rows in this configuration. Here, the result of what performed the unit of the deviation | shift amount of the position of an air jet nozzle by 10 mm and 5 mm is shown. In addition, as a comparative example, a result obtained by gradually shifting the position of the air jet port as shown in Patent Document 1 and a case where the positions of the air ejection ports are not shifted by all nozzles are also shown. Thus, the heat transfer unevenness in the sheet width direction is more gradually shifted (“gradually 5 mm shifted” in FIG. 8) than the one that does not shift the position of the air outlet (“no shift” in FIG. 8). Although reduced, it can be seen that in the present invention, heat transfer unevenness in the sheet width direction is further reduced. Here, when the unit of the deviation amount is 10 mm ("10 mm unit deviation optimization" in FIG. 8) and the one with 5 mm ("5 mm unit deviation optimization" in FIG. 8) are compared, The heat transfer unevenness in the sheet width direction is smaller.

  The present invention can be applied not only to a tenter oven but also to a drying device or the like, but the application range is not limited thereto.

It is a figure for demonstrating the air jet nozzle of this invention. It is a figure which shows the air jet nozzle when not shifting a position. It is a schematic block diagram of the sheet | seat and nozzle which comprise the tenter oven which concerns on one Embodiment of this invention. It is a figure for demonstrating a hole nozzle. It is a figure for demonstrating the position of the air discharge port which shifted the air ejection port gradually. It is a schematic block diagram of an Example. It is a figure which shows the relative position of air jet nozzles. It is a figure which shows the influence which shifting an air jet nozzle has on heat transfer distribution.

Explanation of symbols

1 room 1
2 Room 2
3 Film 4 Nozzle 5 Air outlet

Claims (8)

In a sheet processing apparatus that heats, cools, or dries a sheet conveyed in a certain direction by air from a plurality of nozzles provided in the conveyance direction, each nozzle has a plurality of air jets,
Air jet applied to the nth nozzle (n is an integer greater than or equal to a + 1 and less than the number of nozzles, a is an integer greater than or equal to 1 and the number of nozzles minus 1) counted from the upstream in the sheet conveying direction A sheet processing apparatus in which the position of the outlet in the sheet width direction is determined by the following procedure.
(1) With the nozzles in the a-th to n-th range, the average value in the sheet conveying direction of the heat transfer coefficient of the sheet surface is as follows:
(2) The unevenness in the sheet width direction of the average value is minimized.
(3) The position in the sheet width direction of the air outlet provided to the nth nozzle is obtained,
(4) The position in the sheet width direction of the air outlet of the nth nozzle is determined within a range of ± 10 mm in the sheet width direction from that position.   2. The sheet processing apparatus according to claim 1, wherein a position of the air outlet of the n-th nozzle in the sheet width direction is a position where unevenness in the sheet width direction of the average value of the heat transfer coefficients in the sheet width direction is minimized. The sheet processing apparatus according to claim 1, wherein the unevenness in the sheet width direction is any of the following (1) to (5).
(1) The standard deviation in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction.
(2) The maximum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction—the minimum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction.
(3) (Maximum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction−Minimum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet width direction) / Sheet in the sheet conveyance direction average value of the heat transfer coefficient Maximum value in the width direction.
(4) (Maximum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet width direction−Minimum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet width direction) / Sheet in the sheet transport direction average value of the heat transfer coefficient Minimum value in the width direction.
(5) (Maximum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet conveyance direction−Minimum value in the sheet width direction of the average value of the heat transfer coefficient in the sheet width direction) / Sheet in the sheet conveyance direction average value of the heat transfer coefficient Average value in the width direction. The n, determines the position of the air ejection port of the _{n 1-th} nozzle is first substituted for _{n 1,} then by substituting _{n 2,} in order further _{n 3, n 4, ···,} and _{n m} n The sheet processing apparatus according to any one of claims 1 to 3, wherein a value is substituted into, and a position of an air outlet of m nozzles is determined.
(However,
m is an arbitrary integer of 1 or more and (nozzle number−a) or less.
_{n 1, n 2, ···,} n m are both a + 1 or more, with an integer number of _{nozzles, n 1 <n 2 <···} < arbitrary integer satisfying _{n m.} )   The m is a value of (number of nozzles−a), and the positions of the air outlets of all the nozzles in the (a + 1) -th and subsequent rows are determined from the upstream in the sheet conveying direction. The sheet processing apparatus according to any one of the above.   The sheet processing apparatus according to claim 1, wherein a is 1.   The sheet processing apparatus according to claim 1, wherein the relative positions of the air ejection ports in each nozzle are the same for all nozzles.   A sheet processing method comprising processing a sheet using the sheet processing apparatus according to claim 1.

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