Tube pump and doctor chamber coater

Abstract

To provide a tube pump capable of extending a durable time of a tube and reducing a maintenance frequency.SOLUTION: The tube pump 15 includes the rotating body 50, the housing 51 having the U-shaped side surface 511 and disposed on the side of the rotating body 50, and the tube 52 having the folded portion 520 disposed along the U-shaped side surface 511 so as to pass between the outer edge track of the rotating body 50 and the U-shaped side surface 511, and an elongation of 2% or more and 15% or less is applied to the tube 52 in the longitudinal direction of the tube 52.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tube pump for feeding a liquid and a doctor chamber coater using the same. [Background technology]

[0002] An example of this type of conventionally used tube pump and doctor chamber coater is the configuration shown in Patent Document 1 below. Patent Document 1 discloses a doctor chamber coater equipped with a tube pump. The tube pump has a rotor, a housing (movable housing) with a U-shaped side, and a tube (supply path or pipe) with a folded portion arranged along the U-shaped side so as to pass between the outer edge track of the rotor and the U-shaped side. The narrowed portion of the folded portion is moved by the rotation of the rotor, and the coating liquid is sent to the doctor chamber. The coating liquid stored in the doctor chamber is applied to the substrate via a roll body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-157799 Summary of the Invention [Problem to be solved by the invention]

[0004] When the above-mentioned tube pump is used in a doctor chamber coater, cracks often occur in the tube, requiring maintenance of the tube pump. Since the doctor chamber coater must be stopped during maintenance, it is desirable to reduce the frequency of tube pump maintenance.

[0005] The present invention has been made to solve the above-mentioned problems, and one of its objects is to provide a tube pump and doctor chamber coater that can extend the life of the tube and reduce the frequency of maintenance. [Means for solving the problem]

[0006] The inventors conducted various studies on tube cracks and discovered the following new findings. Specifically, tube cracks originated on the outer surface of the tube and developed toward the interior of the tube. The outer surface is a region repeatedly subjected to stress due to constriction and release, and it was believed that the tube cracks developed due to fatigue fracture. Fatigue fracture occurs when repeated stresses much smaller than the rupture strength are concentrated locally on the tube, causing, for example, rupture of vulcanization (crosslink) points initiated by differences in vulcanization (crosslink) density, voids, and / or foreign matter. The inventors came up with the idea that applying tensile stress to the tube in advance could alleviate compressive stress during constriction and prevent fatigue fracture. Based on this idea, the tube was subjected to a longitudinal elongation of 2% to 15%, which extended the tube's service life and reduced the frequency of maintenance. The present invention was made based on these findings.

[0007] In one embodiment, the tube pump of the present invention comprises a rotor, a housing having a U-shaped side surface and arranged to the side of the rotor, and a tube having a folded portion arranged along the U-shaped side surface so as to pass between the outer edge track of the rotor and the U-shaped side surface, and the tube is subjected to an elongation of 2% to 15% in the longitudinal direction of the tube.

[0008] In one embodiment, the doctor chamber coater according to the present invention includes a doctor chamber in which a coating liquid is stored, and the above-mentioned tube pump connected to the doctor chamber and supplying the coating liquid to and / or discharging the coating liquid from the doctor chamber. [Effects of the Invention]

[0009] According to one embodiment of the tube pump and doctor chamber coater of the present invention, the tube is subjected to an elongation of 2% to 15% in the longitudinal direction of the tube, thereby extending the durability of the tube and reducing the frequency of maintenance. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a structural diagram showing a doctor chamber coater according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view of the chamber body of FIG. 1. [Figure 3] FIG. 2 is a front view showing the tube pump of FIG. [Figure 4] FIG. 4 is a cross-sectional view of the anti-slip mechanism of FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view of the folded portion of FIG. 3. [Figure 6] FIG. 4 is an explanatory diagram showing the tube of FIG. 3 when there is no stretch. [Figure 7] FIG. 4 is an explanatory diagram showing the tube of FIG. 3 when stretched. [Figure 8] FIG. 4 is a front view showing a first modified example of the tube pump of FIG. [Figure 9] FIG. 4 is a front view showing a second modified example of the tube pump of FIG. [Figure 10] FIG. 1 is an explanatory diagram showing a tube pump used in the examples. [Figure 11] FIG. 1 is an explanatory diagram showing a tube pump used in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to each embodiment, and the components can be modified and embodied without departing from the spirit of the present invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in each embodiment. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components of different embodiments may be appropriately combined.

[0012] Fig. 1 is a structural diagram showing a doctor chamber coater 1 according to an embodiment of the present invention, and Fig. 2 is a front view of a chamber main body 101 in Fig. 1. In Fig. 2, the first roll 11 and the like in Fig. 1 are omitted from illustration.

[0013] The doctor chamber coater 1 shown in Figures 1 and 2 is equipment for applying a coating liquid 2 to a substrate 3. Examples of the coating liquid 2 include ink, paint, and chemical conversion treatment liquid. The coating liquid 2 may contain insoluble matter. Insoluble matter is, for example, pigments or aggregates that are dispersed in water or a solvent and do not dissolve. Examples of the substrate 3 include strip-shaped members made of materials such as paper, plastic, or metal. Metal strip-shaped members include cold-rolled steel sheets, various plated steel sheets, aluminum alloy sheets, titanium sheets, and stainless steel sheets.

[0014] As shown in FIGS. 1 and 2, the doctor chamber coater 1 has a doctor chamber 10, a first roll 11, a second roll 12, and a third roll 13.

[0015] The doctor chamber 10 is a container having an internal liquid storage space 10a for storing the coating liquid 2. An opening 10b is provided at the front of the doctor chamber 10, which connects the inside and outside of the liquid storage space 10a.

[0016] The first roll 11 is a rotatable cylindrical member. The first roll 11 can be rotated by the driving force of a driving device (not shown). The first roll 11 has a first outer peripheral surface 11a and is disposed so that the coating liquid 2 in the doctor chamber 10 adheres to the first outer peripheral surface 11a. As shown in the figure, the first roll 11 may be disposed outside the liquid reservoir space 10a (doctor chamber 10) so that the first outer peripheral surface 11a faces the interior of the doctor chamber 10 through the opening 10b. Alternatively, the first roll 11 may be disposed inside the liquid reservoir space 10a (doctor chamber 10) so that the first outer peripheral surface 11a faces the exterior of the doctor chamber 10 through the opening 10b.

[0017] The second roll 12 is a rotatably mounted cylindrical member. The second roll 12 can be rotated by the driving force of a driving device (not shown). The second roll 12 has a second outer peripheral surface 12a and is disposed so that the coating liquid 2 adhering to the first outer peripheral surface 11a of the first roll 11 is transferred to the second outer peripheral surface 12a, and the coating liquid 2 on the second outer peripheral surface 12a is transferred to the object 3 to be coated.

[0018] The third roll 13 is a rotatable cylindrical member, and is arranged so as to sandwich the workpiece 3 between it and the second roll 12. In the doctor chamber coater 1 of this embodiment, the third roll 13 is arranged to the side of the second roll 12 in the horizontal direction, and the workpiece 3 is transported from below to above in the vertical direction.

[0019] When the coating liquid 2 is stored in the liquid storage space 10a in the doctor chamber 10, the first roll 11 is rotated, and the coating liquid 2 is gradually deposited on the first outer peripheral surface 11a of the first roll 11. The coating liquid 2 deposited on the first outer peripheral surface 11a of the first roll 11 is transferred to the workpiece 3 via the second outer peripheral surface 12a of the second roll 12. The third roll 13 supports the workpiece 3 when the coating liquid 2 is transferred from the second roll 12 to the workpiece 3. The first roll 11 is sometimes called a gravure roll, the second roll 12 is called an applicator roll, and the third roll 13 is called a backup roll.

[0020] Coating methods include reverse coating and natural coating. Reverse coating is a method in which coating is performed while the second roll 12 is rotated against the conveying direction of the object 3 to be coated. The rotation direction of each roll during reverse coating is shown in Figure 1. That is, in reverse coating, the first roll 11 rotates counterclockwise, the second roll 12 rotates clockwise, and the third roll 13 rotates clockwise. Natural coating is a method in which coating is performed while the second roll 12 rotates in the same direction as the conveying direction of the object 3 to be coated. In natural coating, the first roll 11 rotates clockwise (opposite to the direction in Figure 1), the second roll 12 rotates counterclockwise (opposite to the direction in Figure 1), and the third roll 13 rotates clockwise.

[0021] When the workpiece 3 is a metal material such as a steel plate, deformations such as central elongation at the center of the plate, edge elongation at the edges of the plate, and / or quarter elongation between them may occur in the workpiece 3. When coating a plate (coil) with poor shape (largely deformed), forcibly controlling the nip pressure with the third roll 13 makes it possible to uniformly transfer the coating liquid 2 from the second roll 12 to the workpiece 3. On the other hand, for a plate with good shape, the third roll 13 does not need to nip, and coating can be performed by pressing the tensioned workpiece 3 against the second roll 12 (no-backing coating).

[0022] A receiving pan 4 may be disposed below the first roll 11 and the second roll 12 to receive the coating liquid 2 dropping from the first roll 11 and the second roll 12 .

[0023] The doctor chamber 10 includes a chamber body 101, a pair of side walls 102 (see FIG. 2), an upper doctor blade 103, and a lower doctor blade 104.

[0024] The chamber body 101 is a part having an external shape that is approximately C-shaped in cross section. The chamber body 101 divides the upper and lower parts of the liquid reservoir space 10a. When the chamber body 101 is viewed alone, the sides of the chamber body 101 are open. The side walls 102 are arranged on both sides in the width direction 10w of the doctor chamber 10, and divide the sides of the liquid reservoir space 10a. The chamber body 101 and the side walls 102 can be made of metal members such as aluminum alloy members.

[0025] The upper doctor blade 103 is a longitudinal member extending from the upper part of the chamber body 101 so that its tip abuts against the first outer peripheral surface 11a of the first roll 11. Similarly, the lower doctor blade 104 is a longitudinal member extending from the lower part of the chamber body 101 so that its tip abuts against the first outer peripheral surface 11a of the first roll 11. The opening 10b of the doctor chamber 10 can be defined by the gap between the tips of the upper doctor blade 103 and the lower doctor blade 104.

[0026] As shown in FIG. 1, when the first roll 11 rotates counterclockwise, the lower doctor blade 104 constitutes a downstream blade located downstream of the opening 10b in the direction of rotation of the first roll 11. When the first roll 11 rotates clockwise, opposite to the orientation shown in FIG. 1, the upper doctor blade 103 constitutes a downstream blade. Recesses are formed on the first outer peripheral surface 11a of the first roll 11. The downstream blade (the lower doctor blade 104 or the upper doctor blade 103) scrapes off the coating liquid 2 adhering to the peripheral surface of the first roll 11 so as to leave the coating liquid 2 in the recesses. This allows a certain amount of the coating liquid 2 to remain on the first outer peripheral surface 11a of the first roll 11.

[0027] The doctor chamber 10 is provided with an opening 10c located on a lower side of the liquid reservoir space 10a. The coating liquid 2 is supplied to the liquid reservoir space 10a through the opening 10c at the lower part of one end in the width direction 10w, and the coating liquid 2 is discharged from the liquid reservoir space 10a through the opening 10c at the lower part of the other end in the width direction 10w. The opening 10c at the lower part of one end constitutes a supply port, and the opening 10c at the lower part of the other end constitutes a discharge port. The direction of the coating liquid 2 may be opposite to that shown in FIG. 2. The position of the opening 10c may be changed as desired.

[0028] As shown in FIG. 2, the doctor chamber coater 1 has a tube pump 15 connected to the doctor chamber 10. The tube pump 15 in this embodiment has a first tube pump 151 and a second tube pump 152. The first tube pump 151 supplies the coating liquid 2 to the doctor chamber 10 (liquid storage space 10a). The second tube pump 152 discharges the coating liquid 2 from the doctor chamber 10 (liquid storage space 10a). The first tube pump 151 and the second tube pump 152 are arranged between the doctor chamber 10 and a coating liquid tank 14 in which the coating liquid 2 is stored, and can circulate the coating liquid 2 between the doctor chamber 10 and the coating liquid tank 14.

[0029] The configuration of the first tube pump 151 may be the same as the configuration of the second tube pump 152. When the first tube pump 151 and the second tube pump 152 are not distinguished from each other, they may be collectively referred to as tube pumps 15. Either the first tube pump 151 or the second tube pump 152 may be omitted, and the coating liquid 2 may be supplied and discharged only by the other pump. Furthermore, either the first tube pump 151 or the second tube pump 152 may be replaced with another pump.

[0030] As shown in FIG. 1, the doctor chamber coater 1 has a mixing rod 16 that stirs the coating liquid 2 in the liquid reservoir space 10a. As described above, the coating liquid 2 may contain insoluble matter. Insoluble matter may settle in the liquid reservoir space 10a when the flow of the coating liquid 2 in the liquid reservoir space 10a is small, for example, when the rotation speed of the first roll 11 is slow. If insoluble matter settles in the liquid reservoir space 10a, there is a risk of unintended patterns appearing on the coated surface of the workpiece 3. The mixing rod 16 stirs the coating liquid 2, thereby preventing the settling of insoluble matter.

[0031] Next, Fig. 3 is a front view showing the tube pump 15 of Fig. 1, and Fig. 4 is a cross-sectional view of the anti-slip mechanism 57 of Fig. 3. As shown in Fig. 3, the tube pump 15 has a rotor 50, a housing 51, and a tube 52.

[0032] The rotating body 50 is a rotatable member. The rotating body 50 may have a support member 501 and a pair of rollers 502. The support member 501 may be a member extending in the radial direction of the rotating shaft 503, and may be fixed to the rotating shaft 503. The support member 501 may be rotated together with the rotating shaft 503 by the driving force of a driving device such as a motor (not shown). The rollers 502 are rotatably supported at both ends of the support member 501. The outer edge track of the rotating body 50 may be a track along which the outer surfaces of the rollers 502 pass when the rotating body 50 rotates.

[0033] The housing 51 is a member having a U-shaped side surface 511 and is disposed to the side of the rotating body 50. The housing 51 may be configured to be able to advance and retreat in a direction approaching the rotating body 50 (leftward in FIG. 3 ) and a direction away from the rotating body 50 (rightward in FIG. 3 ). FIG. 3 shows a state in which the housing 51 is brought close to the rotating body 50. An actuator 53 constituted by, for example, a solenoid actuator may be disposed to the side of the housing 51, and the housing 51 may be advanced and retreated by the driving force of the actuator 53. The actuator 53 may have an actuator fixed portion 530 fixed to a base portion 54 and an actuator movable portion 531 configured to be able to advance and retreat relative to the actuator fixed portion 530, and the actuator movable portion 531 may be fixed to the housing 51. The housing 51 may be provided with an elongated hole 512 extending in the advance and retreat direction of the actuator movable portion 531. A pin 540 fixed to the base portion 54 may be disposed inside the elongated hole 512. The elongated hole 512 and the pin 540 may guide the housing 51 in its forward and backward movement.

[0034] The tube 52 is a member having a folded portion 520 disposed along the U-shaped side surface 511 so as to pass between the outer edge track of the rotor 50 and the U-shaped side surface 511. When the housing 51 is brought close to the rotor 50 as shown in FIG. 3 , the rotor 50 (more specifically, the roller 502) can constrict the folded portion 520 between itself and the U-shaped side surface 511 of the housing 51. The rotation of the rotor 50 moves the narrowed portion of the folded portion 520, thereby allowing the coating liquid 2 to move within the tube 52. The folded portion 520 may be a portion constricted by the U-shaped side surface 511 of the housing 51 and the rotor 50.

[0035] The tube 52 may be made of various materials, including a thermoplastic elastomer tube or a silicone rubber tube. From the viewpoint of durability, the tube 52 is preferably a silicone rubber tube. The hardness of the silicone rubber tube may be in the range of 10 to 80°, for example. The hardness refers to a durometer hardness that can be measured in accordance with JIS K6253 (2012) "Method for determining the hardness of vulcanized rubber and thermoplastic rubber."

[0036] The outer diameter D of the tube 52 (see FIG. 5) may be 15 mm or more and 25 mm or less, and the inner diameter d of the tube 52 (see FIG. 5) may be 7 mm or more and 13 mm or less.

[0037] Joints 55 may be connected to both ends 52a of the tube 52. The tube 52 may be connected to other piping 56 through the joints 55.

[0038] The tube pump 15 may have an anti-slip mechanism 57 that holds both ends of the tube 52. The anti-slip mechanism 57 may fix both ends of the tube 52 to the base 54 so that the positions of the both ends of the tube 52 do not shift in the longitudinal direction of the tube 52. The anti-slip mechanism 57 may fix the tube 52 at a position separated from both ends 52a of the tube 52 in the longitudinal direction of the tube 52. In other words, both ends of the tube 52 may be understood as regions extending in the longitudinal direction of the tube 52 from the exact ends 52a of the tube 52. As shown in FIG. 4 , the anti-slip mechanism 57 may have a restraining body 570 that sandwiches the tube 52 between itself and the base 54, and a fixing member 571 that fixes the restraining body 570 to the base 54. The restraining body 570 and the base 54 may be provided with grooves 570a, 54a into which the tube 52 is fitted. The grooves 570a, 54a may be provided with a plurality of protrusions 570b, 54b arranged side by side in the circumferential direction of the tube 52. The protrusions 570b, 54b may extend in the longitudinal direction of the tube 52. The diameter of a circle inscribed at the tip of the protrusions 570b, 54b is set smaller than the outer diameter D (see FIG. 5) of the tube 52 before it is sandwiched between the restraining body 570 and the base 54, as shown in FIG. 4(b).

[0039] As particularly shown in FIG. 3 , the anti-slip mechanism 57 may have a width in the longitudinal direction of the tube 52. The width of the anti-slip mechanism 57 may be, for example, 15 mm. One end of the anti-slip mechanism 57 in the longitudinal direction of the tube 52, which is located toward the center of the tube 52 (the side away from both ends 52 a of the tube 52), may be referred to as the inner end 57 a of the anti-slip mechanism 57. The portion of the tube 52 from both ends 52 a of the tube 52 to the inner end 57 a of the anti-slip mechanism 57 may be referred to as the fixed portion 521, and the portion of the tube 52 between the fixed portions 521 (in this embodiment, between the inner ends 57 a of the anti-slip mechanism 57) may be referred to as the middle portion 522. The middle portion 522 includes a folded portion 520.

[0040] Next, FIG. 5 is a cross-sectional view of the turning portion 520 in FIG. 3. As described above, the rotation of the rotor 50 moves the narrowed portion of the turning portion 520, which can move the coating liquid 2 within the tube 52. Therefore, each portion of the turning portion 520 is repeatedly narrowed and opened, as shown in FIGS. 5(a) and 5(b). Repeated narrowing and opening causes stresses of narrowing and opening to act repeatedly on the outer surface portion 520a of the turning portion 520, which may cause fatigue failure of the outer surface portion 520a. Therefore, as shown in FIG. 5(c), a crack 520b may form from the outer surface portion 520a toward the inside of the turning portion 520. The crack 520b may cause leakage of the coating liquid 2, and the occurrence of the crack 520b requires maintenance of the tube pump 15. Specifically, the tube 52 needs to be replaced.

[0041] 5(b), when the folded portion 520 is constricted, the outer surface portion 520a may be the outer surface of the folded portion 520 located at both ends in a direction D2 perpendicular to the compression direction D1 of the folded portion 520. When the tube pump 15 is viewed from the front as in FIG. 3, the outer surface portion 520a of the folded portion 520 that appears on the front surface may extend in a U-shape along the neutral line (a portion without bending stress) of the folded portion 520 indicated by the two-dot chain line.

[0042] Fatigue failure occurs when repeated stress much smaller than the breaking strength is concentrated locally, for example, when differences in vulcanization (crosslink) density, voids and / or foreign matter cause the vulcanization (crosslink) points to break. Applying tensile stress to the tube 52 in advance can alleviate the compressive stress during constriction, thereby suppressing fatigue failure. In the tube pump 15 of this embodiment, the tube 52 is stretched by 2% to 15% in the longitudinal direction. Applying such stretch to the tube 52 can extend the service life of the tube 52 and reduce the frequency of maintenance of the tube pump 15.

[0043] It is preferable that the tube 52 be stretched by 5% to 12% in the longitudinal direction of the tube 52. This can more reliably extend the durability of the tube 52 and more reliably reduce the frequency of maintenance of the tube pump 15.

[0044] Next, the stretching of the tube 52 will be described in more detail with reference to Figures 6 and 7 in addition to Figure 3. Figure 6 is an explanatory diagram showing the tube 52 of Figure 3 when it is not stretched, and Figure 7 is an explanatory diagram showing the tube 52 of Figure 3 when it is stretched. The upper parts of Figures 6 and 7 show the tube 52 before it is attached to the tube pump 15, and the lower parts of Figures 6 and 7 show the tube 52 attached to the tube pump 15. Note that when attached to the tube pump 15, the tube 52 extends in a U-shape, but in the lower parts of Figures 6 and 7 it is shown schematically developed into a straight line.

[0045] 6, when the tube 52 is not stretched, the total length of the tube 52 when attached to the tube pump 15 is the same as the total length of the tube 52 before being attached to the tube pump 15. In contrast, when the tube 52 is stretched, as shown in FIG. 7, when the tube 52 is stretched, the total length of the tube 52 when attached to the tube pump 15 is longer than the total length of the tube 52 before being attached to the tube pump 15.

[0046] The total length of the tube 52 when attached to the tube pump 15 is a predetermined length determined by the structure of the tube pump 15, regardless of whether the tube 52 stretches. This predetermined length is sometimes referred to as the structural length. When the total length of the tube 52 before attachment to the tube pump 15 is equal to this structural length, no stretch occurs in the tube pump 15. On the other hand, when the total length of the tube 52 before attachment to the tube pump 15 is shorter than this structural length, the tube pump 15 stretches.

[0047] 3, when the tube pump 15 has the anti-slip mechanism 57, it is believed that no elongation occurs in the fixing portion 521 of the tube 52 (the portion from each end 52a of the tube 52 to the inner end 57a of the anti-slip mechanism 57). In other words, as shown in FIGS. 6 and 7, when the length of the fixing portion 521 is Lf (mm), it is believed that Lf does not change before and after attachment to the tube pump 15.

[0048] The elongation of the tube 52 is considered to occur in the middle portion 522 of the tube 52 (the portion between the inner ends 57a of the anti-slip mechanisms 57). When the elongation of the tube 52 is E (%), the length (initial length) of the middle portion 522 before being attached to the tube pump 15 is L0 (mm), and the length (attached length) of the middle portion 522 when attached to the tube pump 15 is L1 (mm), the elongation of the tube 52 can be expressed as follows: E = {(L0-L1) / L0} × 100

[0049] When attached to the tube pump 15, the length of the tube 52 varies between the inside and outside of the U-shaped bend. The length (particularly L1) of the tube 52 when attached to the tube pump 15 is defined as the length along the neutral line of the tube 52.

[0050] Next, Fig. 8 is a front view showing a first modified example of the tube pump 15 of Fig. 3. In the embodiment shown in Fig. 3, the anti-slip mechanisms 57 fixed both ends of the tube 52 to the base 54. However, as shown in Fig. 8, the anti-slip mechanisms 57 may fix both ends of the tube 52 to the joints 55. The anti-slip mechanisms 57 may be tube bands wrapped around the outer peripheries of the portions of both ends of the tube 52 into which the joints 55 are inserted. Even in this case, the portions from both ends 52a of the tube 52 to the inner ends 57a of the anti-slip mechanisms 57 may be understood as the fixed portions 521.

[0051] Next, Fig. 9 is a front view showing a second modified example of the tube pump 15 of Fig. 3. As shown in Fig. 9, there is also a case where the anti-slip mechanism 57 is omitted and the joint 55 is simply inserted into the tube 52. In such a case, the area from both ends 52a of the tube 52 to the tip 55a of the joint 55 may be understood as the fixed portion 521.

[0052] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention. [Example]

[0053] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0054] The inventors prepared silicone rubber tubes 52 (silicone rubber tubes) of various lengths and attached them to a tube pump 15 having the dimensions shown in Figures 10 and 11. The initial durometer hardness of the silicone rubber tubes 52 was 55±5°. The rotor 50 of the tube pump 15 was rotated at 180 rpm, and the tube pump 15 continued to pump an organic solvent-based paint as the coating liquid 2. The point at which leakage of the coating liquid 2 occurred from the tube 52 was defined as the fatigue limit of the tube 52, and the durability time of the tube 52 up to that fatigue limit was investigated. The results are shown in Table 1 below.

[0055] [Table 1]

[0056] In Table 1, Test Examples 1 to 10 are examples in which tubes 52, with the same outer diameter and other conditions except for the initial length of the intermediate portion 522, were attached to the tube pump 15 shown in FIG. 10. The tube pump 15 in FIG. 10 has a 50 mm length for the fixed portion 521 and a 400 mm length L1 for the attached intermediate portion 522. When the elongation was less than 2%, as in Test Examples 1 and 2, the durability was approximately 80 hours. In contrast, when the elongation was 2% or more and 15% or less, as in Test Examples 3 to 8, the durability was extended to approximately 100 to 520 hours. In particular, when the elongation was 5% or more and 12% or less, as in Test Examples 4 to 7, the durability was significantly extended to approximately 460 to 522 hours. On the other hand, when the elongation was more than 15%, as in Test Examples 9 and 10, the durability was not extended, remaining approximately 60 to 80 hours. Furthermore, when the elongation was more than 15%, a decrease in the flow rate of the coating liquid 2 was observed. These results confirmed that applying an elongation of 2% to 15% to the tube 52 in the longitudinal direction of the tube 52 can extend the durability of the tube 52 and reduce the frequency of maintenance. In particular, it was confirmed that an elongation of 5% to 12% is preferable. It was also confirmed that an elongation of 2% to 15% can suppress a decrease in the flow rate of the coating liquid 2.

[0057] In Table 1, Test Examples Nos. 11 to 18 are examples in which tubes 52, with the same outer diameter and other conditions except for the initial length of the intermediate portion 522, are attached to the tube pump 15 shown in FIG. 11. The tube pump 15 of FIG. 11 is smaller than the tube pump 15 of FIG. 10, with the fixed portion 521 having a length of 50 mm and the length L1 of the intermediate portion 522 in the attached state being 300 mm. In Test Examples Nos. 11 to 18, an extension of the durability time was confirmed when the elongation was 2% or more and 15% or less. Furthermore, in Test Examples Nos. 11 to 18, a significant extension of the durability time was confirmed when the elongation was 5% or more and 12% or less. [Explanation of symbols]

[0058] 1: Doctor chamber coater 2: Coating liquid 10: Doctor Chamber 15: Tube pump 50: Rotating body 51: Housing 511:U-shaped side 52: Tube 520: Turning part 52a: Both ends 57: Anti-slip mechanism

Claims

1. A rotating body; a housing having a U-shaped side surface and disposed to the side of the rotating body; a tube having a folded portion disposed along the U-shaped side surface so as to pass between the outer edge track of the rotating body and the U-shaped side surface; Equipped with The tube is subjected to an elongation of 2% to 15% in the longitudinal direction of the tube. Tube pump.

2. The tube is subjected to an elongation of 5% to 12% in the longitudinal direction of the tube. The tube pump according to claim 1 .

3. The tube further includes a non-slip mechanism for holding both ends of the tube. The tube pump according to claim 1 .

4. The tube is a silicone rubber tube. The tube pump according to claim 1 .

5. A doctor chamber that stores coating fluid inside, a tube pump according to any one of claims 1 to 4, which is connected to the doctor chamber and supplies the coating liquid to the doctor chamber and / or discharges the coating liquid from the doctor chamber; A doctor chamber coater equipped with a

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