Flexible duct

Abstract

To provide a flexible duct which has a shape holding function, can prevent loosening of duct after installation and increase of duct pressure loss caused by the loosening, and enables simplification of duct installation work and standardization and consolidation of a duct length.SOLUTION: A flexible duct 1 includes: a linear reinforcement material 10 forming a spiral shape; a lining 11 attached to an inner periphery of the linear reinforcement material 10; a heat insulation material 12 attached to an outer periphery of the reinforcement material 10; and an outer cover 13 attached to an outer periphery of the heat insulation material 12. The reinforcement material 10 is a tension spring which biases the flexible duct 1 in a manner that the flexible duct 1 contracts along its longitudinal direction L in a state that a tensile force acting in the longitudinal direction L is applied to the flexible duct 1. The lining 11 is formed by a non-woven cloth having air permeability, and the heat insulation material 12 is formed by glass wool.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a flexible duct for constructing a piping flow path for conditioned air in a building air conditioning facility.

Background Art

[0002] Conventional flexible ducts generally have an inner lining provided on the inner circumference of a spiral reinforcing material, a heat insulating material and an outer skin provided on the outer circumference thereof, and are made non-combustible, and are manufactured for each predetermined length. The reinforcing material has a function of maintaining the duct cross-sectional shape and not impairing the air flow path, and is formed by processing a metal or synthetic resin wire or the like in a spiral shape. The inner lining forms the inner wall surface of the air flow path and is formed of a non-woven fabric or the like. The inner lining is made breathable, and sound is transmitted through the inner lining to the heat insulating material region to achieve sound absorption in the heat insulating material region. The outer skin is a duct outer surface material and is formed of a synthetic resin film having weather resistance.

[0003] Conventional flexible ducts with heat insulating materials are packed in a compressed state from the natural length state in order to reduce the size during transportation and are carried into the construction site, but the flexible duct itself is always in a state of trying to restore to the natural length. Therefore, when the compression force during packing is released, the flexible duct extends until it restores to the natural length and cannot maintain the shrunk state during packing. The natural length of a conventional flexible duct refers to the size in the length direction when the flexible duct is placed in a straight and horizontal state without applying an external force in the length direction. When the conventional flexible duct is in the natural length state, the spiral reinforcing material constituting the flexible duct is in a state of being extended in the length direction.

[0004] When installing a conventional flexible duct, as shown in Fig. 9, a flexible duct 100 is suspended in the space between a building structure 101 and a ceiling 103 by using suspension members 102 such as suspension bolts 102a and bands 102b provided at predetermined intervals in the building structure 101. However, if a duct longer than the required length is used, slack 100a may occur in the flexible duct 100 located between the two bands 102b, 102b. Such slack 100a occurs because the duct length is selected considering the height difference at the time of duct laying and a certain amount of extra length from the floor plan of the building, and thus does not exactly match the actual required length, resulting in a certain error in the duct length.

[0005] When slack 100a occurs in the flexible duct 100 shown in Fig. 9, an extra pressure loss is applied to the duct flow path within the slack 100a. This phenomenon occurs prominently when the length of the flexible duct 100 located between the two bands 102b, 102b is longer than necessary at the location where the flexible duct 100 is installed.

[0006] To solve such problems, techniques for maintaining the flexible duct in a contracted state have been disclosed (see, for example, Patent Documents 1 and 2).

[0007] The flexible duct described in Patent Document 1 includes two restraint points arranged at intervals in the axial direction of the duct body of an air-conditioning flexible duct that can be freely bent and stretched, and a bendable operator such as a string or wire connected to the duct body through these restraint points. The operator is movable in the axial direction of the duct body with respect to at least one of the two restraint points, and the duct body can be expanded and contracted by moving the operator.

[0008] The flexible duct described in Patent Document 2 is a flexible duct comprising a core material formed in a coil shape, a heat insulating material disposed as an intermediate material on the outer periphery of the core material, and an exterior material disposed on the outer periphery of the heat insulating material. A bag body containing a wire is attached longitudinally at a predetermined number of predetermined positions between the outer periphery of the exterior material and / or between the core material and the heat insulating material using an adhesive tape, and is capable of freely maintaining its shape.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] In both of the flexible ducts described in Patent Documents 1 and 2, a member for maintaining the shape is added separately from the duct body, so the structure becomes complicated, and there is a concern about an increase in cost due to an increase in the number of parts.

[0011] Also, during the construction of the flexible ducts described in Patent Documents 1 and 2, new operations other than the original duct laying work, such as the operation of a string and the attachment of a wire, may occur, which may also cause a construction delay.

[0012] Therefore, the problem to be solved by the present invention is to provide a flexible duct that has a shape retention function, can prevent the sagging of the duct after construction and an increase in duct pressure loss caused by the sagging, and can simplify the duct construction work and standardize and streamline the duct length.

Means for Solving the Problems

[0013] The flexible duct according to the present invention is a flexible duct having a structure in which a lining is provided on the inner circumference of a spiral reinforcing member, and the reinforcing member is a tension spring that biases the flexible duct to contract along the longitudinal direction in a state where no longitudinal tensile force is applied to the flexible duct. Here, the "tension spring" is also called a "tensile coil spring", and is a coil spring that generates an elastic restoring force (elastic contraction force) when a tensile force is applied in the longitudinal direction (extension direction) of the spring.

[0014] With such a configuration, in the natural length state where no tensile force is applied to the reinforcing member, the reinforcing member is held in a contracted state. Therefore, the expansion phenomenon (the phenomenon of expanding to return to the natural length state when no compressive force is applied) that occurred when the compressive force during packaging was released in the conventional flexible duct does not occur, and it can be extended and used as much as necessary even during duct construction.

[0015] In addition, the extra portion during duct construction is held in a contracted state by the elastic restoring force of the reinforcing member, so the slack during duct laying is reduced, and an increase in pressure loss can be prevented. Also, since the flexible duct itself has a shape-retaining function without the need for additional members or additional work, the workability is improved. When the position of the air conditioner or the air outlet changes at the construction site, it can be dealt with by stretching or contracting the extra length.

[0016] The natural length of the flexible duct according to the present invention refers to the size in the longitudinal direction when the flexible duct is placed in a straight and horizontal state without applying an external force in the length direction. When the flexible duct according to the present invention is in the natural length state, the spiral reinforcing member constituting the flexible duct is in a contracted state in the longitudinal direction.

[0017] Thus, the flexible duct according to the present invention can be adjusted to the duct length required for construction, so that the types of lengths can be reduced and the duct length can be standardized, facilitating management in the manufacturing process and delivery. For example, currently, the duct lengths of flexible ducts are manufactured in increments of 0.5 m up to about 10 m. However, if the duct length can be expanded, contracted, and maintained within a range of about 1.5 to 2 times the total length from the total length, by manufacturing the duct lengths in increments of 1 m or 2 m, it becomes possible to handle various construction conditions. Since the types of duct lengths can be reduced and the duct length can be standardized, it is also advantageous in terms of manufacturing and management.

[0018] Next, as the reinforcing material constituting the flexible duct, a metal spring material or a synthetic resin spring material can be used.

[0019] When the reinforcing material is a metal spring material, it can be manufactured in the same manner as a conventional flexible duct and can maintain high strength. Next, when the reinforcing material is a synthetic resin spring material, the joining means with the inner lining can be welding or adhesion, so that manufacturing is easy and weight reduction is possible compared to a metal spring material.

[0020] Next, in the flexible duct, a heat insulating material and an outer skin can be attached to the outer periphery of the reinforcing material.

[0021] With such a configuration, heat insulation can be provided to the flexible duct while maintaining the above-described effects.

[0022] Next, in the flexible duct, the inner lining can be formed of a breathable non-woven fabric.

[0023] With such a configuration, sound permeates through the non-woven fabric into the region of the heat insulating material (glass wool) and is silenced in the region of the heat insulating material (glass wool), so that the quietness of the flexible duct can be enhanced.

Effects of the Invention

[0024] According to the present invention, there can be provided a flexible duct having a shape-retaining function, capable of preventing the slack of the duct after construction and the increase in duct pressure loss caused by the slack, and capable of simplifying the duct construction work and standardizing and aggregating the duct lengths.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

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Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0026] Hereinafter, a flexible duct 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8. First, the structure of the flexible duct 1 will be described with reference to FIGS. 1 to 5.

[0027] As shown in FIGS. 1 to 3, the flexible duct 1 includes a linear reinforcing member 10 having a spiral shape, a lining 11 attached to the inner circumference of the linear reinforcing member 10, a heat insulating material 12 attached to the outer circumference of the reinforcing member 10, and a skin 13 attached to the outer circumference of the heat insulating material 12. The reinforcing member 10 is a tension spring that biases the flexible duct 1 to contract along the longitudinal direction L in a state where no tensile force in the longitudinal direction L is applied to the flexible duct 1. The lining 11 is formed of a breathable non-woven fabric, and the heat insulating material 12 is formed of glass wool.

[0028] As shown in FIG. 4, a single reinforcing member 10 constituting the flexible duct 1 is a tension spring formed in a spiral shape using a metal spring material, and is also called a tension coil spring. As shown in FIG. 4(a), when no tensile force P in the longitudinal direction L is applied to the single reinforcing member 10 and it is stationary in a linear and horizontal state, the length S1 in the longitudinal direction (extension direction) L is in the most contracted state. On the other hand, as shown in FIG. 4(b), when a tensile force P in the longitudinal direction (extension direction) L is applied to the reinforcing member 10, it extends to a length S2 corresponding to the magnitude of the tensile force P within the elastic limit range, and is maintained in a state where an elastic restoring force (elastic contraction force) is generated.

[0029] Therefore, as shown in FIG. 5(a), when the flexible duct 1 incorporating the reinforcing member 10 is stationary in a linear and horizontal state without a tensile force P in the longitudinal direction L, it is biased by the reinforcing member 10 to contract along the longitudinal direction L, and the length F1 in the longitudinal direction (extension direction) L of the flexible duct 1 is maintained in a contracted state (natural length state). On the other hand, as shown in FIG. 5(b), when a tensile force P in the longitudinal direction (extension direction) L is applied to the flexible duct 1, it extends to a length F2 corresponding to the magnitude of the tensile force P within the elastic limit range of the reinforcing member 10, and is maintained in a state where an elastic restoring force (elastic contraction force) by the reinforcing member 10 is generated.

[0030] Thus, in the flexible duct 1, when the tensile force P in the longitudinal direction L is not applied, the reinforcing member 10 is held in a contracted state (the natural length state shown in Fig. 5(a)). Therefore, the stretching phenomenon (the phenomenon of stretching back to the natural length state when no compressive force is applied) that occurred when the compressive force in the packaged state was released in the conventional flexible duct does not occur. Therefore, during duct construction, as shown in Fig. 5(b), it can be stretched as required and used.

[0031] In the actual flexible duct 1, as shown in Fig. 5(a), since the lining 11, the heat insulating material 12, and the outer skin 13 are added to the reinforcing member 10, the reinforcing member 10 in the state shown in Fig. 5(a) does not shrink to the contracted state without external force like the single reinforcing member 10 shown in Fig. 4(a), but is in a state slightly stretched from the state of Fig. 4(a) due to the thickness of the heat insulating material 12 and the like. As a result, the reinforcing member 10 biases the lining 11, the heat insulating material 12, and the outer skin 13 to contract along the longitudinal direction L.

[0032] Next, a construction method of the flexible duct 1 will be described with reference to Figs. 6 to 8. Note that the construction method shown in Figs. 6 to 8 is an example and is not limited thereto.

[0033] When constructing the flexible duct 1, as shown in Fig. 6, using hanging members 3 such as hanging bolts 3a and bands 3b provided at predetermined intervals on the building body 2, the flexible duct 1 is suspended into the space between the building body 2 and the ceiling 5. In the case of this embodiment, the base end portion 1b of the flexible duct 1 is connected to the chamber 4, and the vicinity of the center in the longitudinal direction L of the flexible duct 1 is suspended and held by the hanging member 3 on the building body 2.

[0034] In the state shown in Fig. 6, since the tensile force P in the longitudinal direction L is not applied to the flexible duct 1, it is biased by the reinforcing member 10 (see Fig. 5) to contract along the longitudinal direction L, and the length in the longitudinal direction (stretching direction) L remains in a contracted state.

[0035] After that, in order to extend the length of the flexible duct 1 in the state shown in FIG. 6 according to the situation at the construction site, when a tensile force P in the longitudinal direction (extension direction) L is applied to the tip end portion 1a side of the flexible duct 1, as shown in FIGS. 7 and 8, the flexible duct 1 extends to a length corresponding to the magnitude of the tensile force P.

[0036] When the flexible duct 1 has extended to a predetermined length, if a suspension member 3 is attached to the tip end portion side (the side opposite to the base end portion 1b) of the flexible duct 1 and suspended from the building body 2 and the tensile force P in the longitudinal direction (extension direction) L is kept applied, the flexible duct 1 is kept in a state where an elastic restoring force (elastic contraction force) by the reinforcing member 10 is generated.

[0037] After that, when it is necessary to further extend the flexible duct 1 and connect it to equipment (not shown) such as an air conditioner or an air outlet, as described above, by increasing the tensile force P in the longitudinal direction (extension direction) L at a portion near the tip end portion 1a (see FIG. 6) of the flexible duct 1, it can be extended to a required length within the elastic limit range of the reinforcing member 10, and the flexible duct 1 can be connected to equipment such as an air conditioner or an air outlet.

[0038] As described above, in the flexible duct 1, in the natural length state where no tensile force P is applied in the longitudinal direction, the reinforcing member 10 is held in a contracted state (the state shown in FIG. 5(a)). Therefore, the extension phenomenon (the phenomenon of trying to return to the natural length (the length when no compressive force is applied) and extending) that occurred when the compressive force during packaging was released in a conventional flexible duct does not occur, and during duct construction, as shown in FIGS. 7 and 8, it can be extended by the required amount and used.

[0039] In addition, when installing the flexible duct 1, the extra portion is held in a contracted state by the elastic restoring force of the reinforcing material 10, so that the slack during duct laying is reduced, and an increase in pressure loss can be prevented. Furthermore, since the flexible duct 1 itself has a shape-retaining function (shrinking function), the workability is good. Therefore, when the position of the air conditioner or the air outlet changes at the construction site, it is possible to cope by stretching or shrinking the extra length of the flexible duct 1.

[0040] In this way, since the flexible duct 1 can be adjusted to the duct length required for construction and used, the types of lengths can be reduced, the duct length can be standardized, and the management of the manufacturing process and delivery of the flexible duct 1 becomes easy. For example, currently, the duct lengths of flexible ducts are manufactured in 0.5 m increments up to about 10 m, but if the length of the flexible duct 1 can be stretched and held within a range of about 1.5 to 2 times its total length, the types of lengths of the flexible duct 1 can be manufactured in 1 m increments or 2 m increments to cope with construction conditions. Therefore, the types of lengths can be reduced, and the length of the flexible duct 1 can be standardized. Accordingly, it becomes possible to select a flexible duct 1 with an appropriate length based on the building design drawings from the standardized flexible duct 1.

[0041] In the present embodiment, since the reinforcing material 10 constituting the flexible duct 1 is a metal spring material, it can be manufactured in the same manner as a conventional flexible duct and can maintain high strength. On the other hand, when the reinforcing material 10 is a synthetic resin spring material, the joining means with the lining 11 (see FIG. 3) can be welding or adhesion, so that the manufacturing is easy and the weight can be reduced compared to a metal spring material.

[0042] As shown in FIG. 3, in the flexible duct 1, since the heat insulating material 12 and the outer skin 13 are attached to the outer periphery of the reinforcing material 10, the flexible duct 1 can be provided with heat insulating properties while maintaining the above-described effects.

[0043] Also, as shown in FIG. 3, in the flexible duct 1, if the inner lining 11 is formed of a breathable nonwoven fabric and the heat insulating material 12 is formed of glass wool, sound will permeate through the nonwoven fabric into the region of the heat insulating material 12 (glass wool) and be silenced in the region of the heat insulating material 12 (glass wool), so that the quietness of the flexible duct 1 can be enhanced.

[0044] The flexible duct 1 described with reference to FIGS. 1 to 8 shows an example of the flexible duct according to the present invention, and the flexible duct according to the present invention is not limited to the above-described flexible duct 1.

Industrial Applicability

[0045] The flexible duct according to the present invention can be widely used in industrial fields such as the construction industry and the building industry as part of air conditioning equipment installed in various buildings.

Explanation of Reference Numerals

[0046] 1 Flexible duct 1a Tip 1b Base end 2 Building body 3 Hanging member 3a Hanging bolt 3b Band 4 Chamber 5 Ceiling 10 Reinforcing material 11 Inner lining 12 Heat insulating material 13 Outer skin F1,F2,S1,S2 Length L Longitudinal direction P Tensile force

Claims

1. A flexible duct having a structure in which a lining is provided on the inner circumference of a spiral reinforcing material, wherein the reinforcing material is a tension spring that biases the flexible duct to contract along the longitudinal direction in a state where no longitudinal tensile force is applied to the flexible duct, and a heat insulating material and an outer skin are provided on the outer circumference of the reinforcing material.

2. The flexible duct according to Claim 1, wherein the reinforcing material is a metal spring material or a synthetic resin spring material.

3. The flexible duct according to Claim 1 or 2, wherein the lining is formed of a breathable non-woven fabric.

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