Flexible synthetic resin pipe

Abstract

To provide a flexible synthetic resin pipe that has excellent fluid flowability compared to conventional flexible synthetic resin pipes having the same outer diameter, and has excellent fluid flowability even when bent.SOLUTION: A flexible synthetic resin pipe P includes: a pipe main body 1 having an inner peripheral surface formed into a substantially flat shape and containing soft synthetic resin, where protrusion pieces 2 formed by folding a plurality of flexible pieces 21 containing the soft synthetic resin in an expandable manner protrude outward in a spiral manner; and a reinforcing body 3 wound spirally between the protrusion pieces on an outer peripheral surface of the pipe main body 1, and containing hard synthetic resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a flexible synthetic resin pipe having a main pipe body made of soft synthetic resin and a reinforcing body wound spirally around the outer peripheral surface thereof. [Background technology]

[0002] Conventionally, flexible synthetic resin pipes have been provided, for example, with a structure as described in Patent Document 1.

[0003] Specifically, Patent Document 1 describes an abrasion-resistant composite hose in which a reinforcing ridge with a circular cross section is spirally wound around the outer peripheral surface of a tubular body made of soft synthetic resin, with part of the ridge embedded in the tubular body, and a rubber layer is layered on the inner peripheral surface of the tubular body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-222183 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned wear-resistant composite hose ensures its flexibility by having the outer peripheral wall portion, which is curved in a convex arc, expand while the inner peripheral wall portion, which is curved in a concave arc, compresses. However, this causes the compressed inner peripheral wall portion to protrude into the composite hose, which creates a problem of resistance to the flow of fluids such as water and air flowing through the composite hose.

[0006] Furthermore, as described above, when the abrasion-resistant composite hose is bent, the outer peripheral wall portion that curves into a convex arc stretches. However, as the degree of bending increases, the stretchable length of the outer peripheral wall portion cannot cover the stretchable length required to bend the composite hose, and the composite hose flattens into an elliptical cross section. As a result, there is a problem in that the fluid flow through the composite hose is reduced.

[0007] Therefore, it is conceivable to reduce the area of the abrasion-resistant composite hose where the reinforcing ridges are attached, thereby improving the extensibility of the peripheral wall, and instead increasing the height of the reinforcing ridges, thereby maintaining the mechanical strength of the entire abrasion-resistant composite hose. However, if the reinforcing ridges are made taller, the outer diameter of the abrasion-resistant composite hose will increase. Therefore, if an attempt is made to maintain the outer diameter of the abrasion-resistant composite hose, the inner diameter of the abrasion-resistant composite hose, i.e., the fluid flow path, will become smaller accordingly, resulting in another problem of reduced fluid flow.

[0008] Furthermore, hoses connecting the indoor and outdoor units of an air conditioner are routed through access holes provided in structures such as buildings, condominiums, and detached homes. In recent years, in order to maintain humidity in rooms where air conditioners are installed, humidification hoses are sometimes bundled and routed through the access holes, in addition to refrigerant conduits connecting the indoor and outdoor units of the air conditioner and drain hoses for discharging drain.

[0009] On the other hand, the installation holes provided in structures are often existing ones, and it is difficult to install new installation holes or enlarge installation holes. Therefore, there is a demand for hoses connecting the indoor and outdoor units of air conditioners that have excellent fluid flow properties while maintaining or reducing their outer diameter.

[0010] Furthermore, since hoses that are routed from the inside of the room through the routing hole to the outside of the room are routed along the exterior wall, the hoses that exit the routing hole are curved, and it is necessary to ensure that fluid can flow through them even in this curved state.

[0011] The present invention provides a flexible synthetic resin pipe that has superior fluid flowability compared to conventional flexible synthetic resin pipes having the same outer diameter, and that maintains excellent fluid flowability even when bent. [Means for solving the problem]

[0012] The flexible synthetic resin pipe of the present invention comprises: a pipe main body having an inner circumferential surface formed into a substantially flat surface and made of a soft synthetic resin, the pipe main body having a protruding piece formed by overlapping a plurality of flexible pieces made of the soft synthetic resin in a freely expandable manner and protruding outward in a spiral shape; The pipe main body further includes a reinforcing member that is spirally wound between the protruding pieces on the outer circumferential surface of the pipe main body and that contains a hard synthetic resin. [Effects of the Invention]

[0013] The flexible synthetic resin pipe of the present invention has a pipe main body containing soft synthetic resin and a substantially flat inner peripheral surface, which reduces the resistance inside the pipe to fluids such as water and air, reduces pressure loss, allows the fluid to flow smoothly, and prevents dust and other particles from accumulating or adhering to the inner peripheral surface.Furthermore, the flexible synthetic resin pipe of the present invention has a reinforcing body containing hard synthetic resin wound helically between the protruding pieces on the outer peripheral surface of the pipe main body, which gives it pressure resistance.

[0014] Furthermore, the protruding pieces of the main body of the flexible synthetic resin pipe are made up of multiple flexible pieces that can be deployed and are flexible. Therefore, when stress is applied to the flexible synthetic resin pipe, in addition to the mechanical strength provided by the above-mentioned reinforcing body, the protruding pieces can absorb the stress by deforming or by the flexible pieces of the protruding pieces shifting relative to each other, and the flexible synthetic resin pipe has excellent resistance to stresses such as compressive stress.

[0015] The flexible synthetic resin pipe of the present invention has a protruding piece formed by stacking a plurality of flexible pieces containing soft synthetic resin in a freely expandable manner on top of each other, which is spirally protruding outward from the pipe main body. Therefore, by expanding the flexible pieces of the protruding piece apart from each other, the pipe main body can be easily extended in the longitudinal direction.

[0016] Therefore, when the flexible synthetic resin pipe is bent, the outer peripheral wall of the pipe main body, which is curved in a convex arc, expands due to the deployment of the protruding pieces, and the inner peripheral wall of the pipe main body, which is curved in a concave arc, does not need to be compressed. As a result, the inner peripheral wall of the pipe main body, which is curved in a concave arc, is not compressed and protrudes inward, which does not cause fluid resistance, and smooth fluid flow can be maintained.

[0017] Furthermore, the protruding pieces of the main body of the flexible synthetic resin pipe are displaced relative to one another, thereby imparting excellent bendability to the flexible synthetic resin pipe, and the flexible synthetic resin pipe has excellent bendability.

[0018] Furthermore, since the outer peripheral wall portion of the main body of the flexible synthetic resin pipe that curves in a convex arc shape is stretched, the flexible synthetic resin pipe can be easily bent without being deformed into a flattened shape or buckling when bent.

[0019] Furthermore, when the flexible synthetic resin pipe is bent, the protruding pieces of the pipe main body are deployed, separating the flexible pieces, and gaps are formed between the flexible pieces. However, these gaps formed between the flexible pieces are formed on the inner surface of the pipe main body, spiraling in the longitudinal direction of the pipe main body, and the fluid that flows into these spirally formed gaps can flow smoothly within the pipe main body as they spirally rotate without generating fluid resistance.

[0020] Therefore, even if the flexible synthetic resin pipe is greatly curved, the fluid can flow while swirling in a spiral within the gap formed between the flexible pieces of the protruding pieces, thereby providing excellent fluid flowability within the flexible synthetic resin pipe.

[0021] Furthermore, since the protruding pieces of the flexible synthetic resin pipe of the present invention are flexible, they can be bent as needed to conform to the outer circumferential surface of the pipe main body, allowing the outer diameter to be reduced without affecting the fluid flow characteristics within the flexible synthetic resin pipe. Therefore, the flexible synthetic resin pipe of the present invention has superior fluid flow characteristics compared to conventional synthetic resin pipes of the same diameter.

[0022] In the above-mentioned flexible synthetic resin pipe, if the opposing surfaces of the reinforcing body and the protruding pieces are not integrated, the flexible pieces of the protruding pieces can be deployed over their entire length from the base end to the tip, or the flexible pieces can be shifted relative to each other, which allows the degree of elongation of the main body of the flexible synthetic resin pipe to be increased when the flexible synthetic resin pipe is bent, thereby improving the bendability of the flexible synthetic resin pipe.

[0023] In the above-mentioned flexible synthetic resin pipe, if the flexible pieces constituting the protruding piece are configured to be able to move relative to each other in the radial direction of the pipe main body, when stress is applied to the flexible synthetic resin pipe, the flexible pieces of the protruding piece will shift relative to each other in the radial direction of the pipe main body, thereby absorbing the stress, and the flexible synthetic resin pipe will have better resistance to stresses such as compressive stress. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a cross-sectional view showing a flexible synthetic resin pipe. [Figure 2] FIG. 2 is a cross-sectional view showing a main part of a flexible synthetic resin pipe. [Figure 3] FIG. 10 is a cross-sectional view showing a state in which the flexible synthetic resin pipe is bent. [Figure 4] 10 is a cross-sectional schematic view showing a flexible synthetic resin pipe with a protruding piece in a bent state. FIG. [Figure 5] FIG. 10 is a cross-sectional view showing another form of the protruding piece. [Figure 6] FIG. 10 is a cross-sectional view showing another embodiment of the reinforcing body. [Figure 7] 1 is a schematic diagram showing a manufacturing method of a flexible synthetic resin pipe. DETAILED DESCRIPTION OF THE INVENTION

[0025] An example of a flexible synthetic resin pipe of the present invention will be described with reference to the drawings. In FIGS. 1 to 4, the flexible synthetic resin pipe P has a pipe main body 1 made of a soft synthetic resin, the inner circumferential surface of which is formed into a substantially flat surface of a constant diameter along its entire length. The term "substantially flat" means that the flat surface may have irregularities that do not affect the fluid flow. Examples of irregularities that do not affect the fluid flow include, for example, irregularities resulting from the thickness of a synthetic resin strip at the overlapping portion between the rear end of a leading synthetic resin strip and the front end of a trailing synthetic resin strip, as described below, when the pipe main body is formed by spirally winding a synthetic resin strip having a predetermined width, and irregularities resulting from a small gap formed between the rear end surface of the leading synthetic resin strip and the front end surface of the trailing synthetic resin strip. Examples of the soft synthetic resin constituting the pipe main body 1 and the protruding piece 2 described below include soft olefin-based resins such as soft polyethylene and soft polypropylene, and soft vinyl chloride resin. The content of the soft synthetic resin in the pipe main body 1 is preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and more preferably 99% by mass or more.

[0026] The pipe main body 1 of the flexible synthetic resin pipe P is formed into a cylindrical shape by spirally winding a soft synthetic resin strip having a certain width, and its interior serves as a fluid flow passage 1a through which liquids and gases flow. Specifically, the pipe main body 1 is formed into a cylindrical shape by spirally winding a soft synthetic resin strip and butting the rear end of the preceding synthetic resin strip and the front end of the succeeding synthetic resin strip together to fuse them together.

[0027] Alternatively, the rear end of the preceding synthetic resin strip and the front end of the following synthetic resin strip may be overlapped and fused together. Alternatively, a small gap may be formed between the rear end surface of the preceding synthetic resin strip and the front end surface of the following synthetic resin strip, and the preceding and following synthetic resin strips may be integrated together by a reinforcing member, which will be described later.

[0028] The flexible synthetic resin pipe P has a main pipe body 1, which is integrally provided with protruding pieces 2 that protrude outward at a constant height and in a spiral pattern at a constant pitch on the outer circumferential surface of the main pipe body 1. That is, the protruding pieces 2 are formed outward in a continuous spiral pattern at a constant pitch in the longitudinal direction on the outer circumferential surface of the main pipe body 1.

[0029] The protruding piece 2 is formed by folding a central portion in the width direction of a soft synthetic resin strip having a fixed width in half in a mountain fold shape, and is composed of a pair of flexible pieces 21, 21 that can be unfolded. The flexible pieces 21, 21 have their tips integrated over their entire lengths, and their base ends connected and integrated to the pipe main body 1 over their entire lengths. The gap 21a formed between the flexible pieces 21, 21 of the protruding piece 2 is open over the entire length of the protruding piece 2. When stress is applied that bends the flexible synthetic resin pipe P and stretches the peripheral wall portion of the pipe main body 1, the protruding piece 2 unfolds the flexible pieces 21, 21 away from each other, widening the gap 21a, and thereby stretching the peripheral wall portion in accordance with the curvature of the pipe main body 1.

[0030] The protruding piece 2 contains the same soft synthetic resin as the pipe main body 1, is flexible, and is configured to be bendable to fit along the outer peripheral surface of the pipe main body 1. Therefore, when the flexible synthetic resin pipe P is to be disposed in a narrow installation hole, for example, the protruding piece 2 can be bent to fit along the outer peripheral surface of the pipe main body 1 as shown in Fig. 4, thereby reducing the outer diameter of the flexible synthetic resin pipe P and making it easy to install the flexible synthetic resin pipe P in the installation hole even when the installation hole is small. The content of the soft synthetic resin in the protruding piece 2 is preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and more preferably 99% by mass or more.

[0031] In the above, the protruding piece 2 has been described as being formed from a pair of flexible pieces 21, 21, but as shown in Fig. 5, each of the pair of flexible pieces 21, 21 may be folded from the center in its protruding direction (inward / outward direction) toward the space between the flexible pieces 21, 21 to form an M-shaped cross section. That is, each of the pair of flexible pieces 21 may be folded in half to form a first flexible piece portion 21b and a second flexible piece portion 21c, and the first flexible piece portions 21b, 21b of the flexible pieces 21, 21 may be inserted and disposed between the second flexible piece portions 21c, 21c to form the pair of flexible pieces 21, 21 in an M-shaped cross section. When the flexible synthetic resin pipe P is bent, the flexible pieces 21, 21 of the protruding piece 2, each having an M-shaped cross section, unfold at the outer peripheral wall of the pipe main body 1, which is curved in a convex arc, and adjacent flexible piece portions move away from each other, widening the gap 21a, thereby allowing the peripheral wall to expand in accordance with the curvature of the pipe main body 1. Folding the flexible pieces 21, 21 of the protruding piece 2 in this manner is preferable because it reduces the dimensions of the protruding piece in the inward and outward directions and reduces the outer diameter of the flexible synthetic resin pipe while maintaining the degree of extension of the flexible pieces 21, 21 of the protruding piece 2 when unfolded. While Fig. 5 shows the flexible pieces 21, 21 of the protruding piece 2 folded in half, the folding is not limited to folding in half, and the remaining flexible piece may be folded multiple times (three or more times) and inserted and disposed between the flexible piece portions located at both ends of the pair of flexible pieces 21, 21 in a folded state.

[0032] A reinforcing body 3 containing a hard synthetic resin is wound around the entire length of the helical circumferential surface 11 formed between the helical protruding pieces 2, 2 on the outer circumferential surface of the pipe main body 1 of the flexible synthetic resin pipe P, i.e., the helical circumferential surface 11 formed on the opposing surface between the leading protruding piece 2 and the trailing protruding piece 2. Examples of the hard synthetic resin constituting the pipe main body 1 include hard olefin-based resins such as hard polyethylene and hard polypropylene, and hard vinyl chloride resin. The content of the hard synthetic resin in the reinforcing body 3 is preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and more preferably 99% by mass or more.

[0033] The reinforcing member 3 is formed by spirally winding a flat strip made of hard synthetic resin having substantially the same width as the spiral circumferential surface 11 around the spiral circumferential surface 11 of the pipe main body 1 and fusing and integrating it with the pipe main body 1. The reinforcing member 3 imparts mechanical strength to the flexible synthetic resin pipe P and provides durability against stresses such as compressive stress. As shown in Fig. 6, the outer circumferential surface of the reinforcing member 3 may be formed with ridges 31 extending in the longitudinal direction thereof to improve the mechanical strength of the reinforcing member 3.

[0034] It is preferable that both end faces 3a, 3a in the width direction of the reinforcing member 3 are not integrated with the opposing base end faces of the flexible pieces 21 of the protruding pieces 2. The entire length of the protruding pieces 2 from the base end to the tip can be used to fully exert the stretching action of the pipe main body 1 due to the expansion of the protruding pieces 2, and the protruding pieces 2 can be bent from the base end along the outer peripheral surface of the pipe main body 1, thereby making it possible to further reduce the outer diameter of the flexible synthetic resin pipe P.

[0035] Next, a method for manufacturing the flexible synthetic resin pipe P will be described. The soft synthetic resin strip S1 that constitutes the pipe main body 1 is extruded from an extruder, and the softened soft synthetic resin strip is bent at its widthwise central portion into a V-shaped cross section to form a bent portion S11 that becomes the protruding piece 2. The softened soft synthetic resin strip is then spirally wound around a rotating mandrel to continuously manufacture the pipe main body 1. At this time, the rear end face of the preceding soft synthetic resin strip and the front end face of the subsequent soft synthetic resin strip are adjusted so as to abut against each other and be heat-sealed together. Alternatively, the rear end of the preceding soft synthetic resin strip and the front end of the subsequent soft synthetic resin strip may be overlapped and heat-sealed together.

[0036] Next, a hard synthetic resin strip S2 constituting the reinforcing member 3 is extruded from another extruder, and the semi-molten hard synthetic resin strip S2 is continuously spirally supplied between the protruding pieces 2, 2 on the outer circumferential surface of the pipe main body 1, and the hard synthetic resin strip S2 is heat-sealed and integrated with the spiral circumferential surface between the bent portions S11, S11 that will become the protruding pieces of the pipe main body. In this state, both end faces in the width direction of the hard synthetic resin strip S2 and the opposing base end of the bent portion S11 with a V-shaped cross section of the soft synthetic resin strip S1 are spaced apart so as not to be heat-sealed to each other.

[0037] Thereafter, the speed at which the soft synthetic resin strip S1 and the hard synthetic resin strip S2 are advanced on the mandrel is made slower than the speed at which the soft synthetic resin strip S1 and the hard synthetic resin strip S2 were advanced when they were supplied onto the mandrel, and the soft synthetic resin strip S1 is cooled and solidified while being shaped so that the V-shaped cross-sectional bent portion S11 is formed in the soft synthetic resin strip S1 and the portions that will become the flexible pieces are in close contact with each other, thereby continuously producing flexible synthetic resin pipes P.

[0038] At the time when the speed of travel of the soft synthetic resin strip S2 and the hard synthetic resin strip S1 on the mandrel is slowed down, the soft synthetic resin strip S1 and the hard synthetic resin strip S2 are cooled and adjusted so that the strips do not become heat-fused together, while the soft synthetic resin strip S1 is at a temperature that allows it to be shaped, and the parts that become the flexible pieces of the protruding piece 2 are shaped so that they are in close contact with each other.

[0039] Next, we will explain how to use the flexible synthetic resin pipe P. The flexible synthetic resin pipe P is used by circulating a fluid through a fluid flow passage 1a formed inside the pipe main body 1. The flexible synthetic resin pipe P has a substantially flat inner surface, which reduces the internal resistance of the fluid flowing inside the flexible synthetic resin pipe P and reduces pressure loss, ensuring the necessary amount of fluid flow.

[0040] Furthermore, the protruding pieces of the flexible synthetic resin pipe P are flexible and can be bent to fit the outer surface of the pipe main body 1 as needed, so that the outer diameter can be reduced without affecting the flow of fluid through the fluid flow passage 1a, and the pipe can be easily installed in narrow installation locations.

[0041] The flexible synthetic resin pipe P can be bent as needed, but when bent, the protruding pieces 2 expand by separating the flexible pieces 21, 21, and the outer circumferential wall portion curved in a convex arc is stretched, so there is no need to compress the inner circumferential wall portion curved in a concave arc. Therefore, even when bent, the flexible synthetic resin pipe P can generally prevent unevenness from being formed inside the pipe main body 1 due to compression, reducing the resistance of the fluid inside the pipe and reducing pressure loss, thereby ensuring the necessary flow rate of fluid.

[0042] In this way, even when the flexible synthetic resin pipe P is bent, it is possible to reduce the internal resistance of the fluid flowing through the fluid flow passage 1a of the pipe main body 1, thereby reducing pressure loss, and since the flexible protruding pieces can be bent to reduce the outer diameter, it is possible to ensure the necessary amount of fluid flow even while reducing the outer diameter.

[0043] Furthermore, even when flexible synthetic resin pipes P are used as hoses connecting the indoor and outdoor units of an air conditioner, for example, as drain hoses, the flexible synthetic resin pipes P can be easily inserted into installation holes in the structure while bundled together with the refrigerant conduits and humidifier hoses connecting the indoor and outdoor units of the air conditioner, and the indoor and outdoor units of the air conditioner can be easily connected using hoses.

[0044] Furthermore, as described above, the flexible synthetic resin pipe P can be bent while ensuring the flow rate of liquid within the fluid flow passage 1a of the pipe main body 1, so it is easy to bend it after it has exited the installation hole of the structure and then install it along the outer wall surface, allowing for smooth piping work. [Explanation of symbols]

[0045] 1 Main body 1a Fluid flow path 2 protruding piece 21 Flexible piece 21a Gap 3 Reinforcement 11 Peripheral surface P Flexible synthetic resin pipe

Claims

1. a pipe main body having an inner circumferential surface formed into a substantially flat surface and made of a soft synthetic resin, the pipe main body having a protruding piece formed by overlapping a plurality of flexible pieces made of the soft synthetic resin in a freely expandable manner and protruding outward in a spiral shape; a reinforcing member spirally wound between the protruding pieces on the outer circumferential surface of the pipe main body, the reinforcing member comprising a hard synthetic resin.

2. 2. The flexible synthetic resin pipe according to claim 1, wherein the opposite end surfaces of the reinforcing member and the opposing surfaces of the protruding pieces are not integrated.

3. 3. The flexible synthetic resin pipe according to claim 1, wherein the flexible pieces constituting the protruding piece are configured to be capable of relative displacement with respect to each other in the radial direction of the pipe main body.

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