JPH0221224Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a bellows tube made of synthetic resin, and particularly to a bellows tube suitable for passing fluids such as drainage.

(Prior Art) A synthetic resin bellows tube having a corrugated cross-sectional shape in the tube axis direction is well known. Since this bellows tube has alternating peaks and valleys, it can be easily bent due to the deformation of these peaks and valleys, making it highly flexible, and the peaks and valleys are annularly reinforced. Because it functions as a rib, it has the excellent property of being difficult to deform even when subjected to external force in the radial direction, and is widely used in a variety of applications.

(Problem that the invention aims to solve) However, the inner surface of this bellows tube naturally has unevenness formed in the tube axis direction, so when a fluid containing solids is passed through, the solids become uneven. There are problems such as the tube getting caught and stopping the flow, solid matter accumulating and solidifying, and even when it does not contain solid matter, the flow resistance is large, so its use as a pipe for passing fluid has been limited.

For this purpose, a tube body such as a synthetic resin tube with smooth inner and outer circumferential surfaces is inserted into the inner circumferential surface of the bellows tube, and the outer circumferential surface of this tube body is integrated with the inner surface of the trough of the bellows tube. However, in such a structure, even though the tube body with a smooth inner surface allows for good fluid flow, the flexibility of the bellows tube is not good enough for the tube body. The advantages of the bellows tube cannot be fully utilized.

The object of the present invention is to provide a bellows tube that solves these problems.

(Means for Solving the Problems) In order to achieve the above object, the bellows tube of the present invention has a corrugated cross-sectional shape in the direction of the tube axis, and is a synthetic material in which annular peaks and valleys are alternately formed. A synthetic resin belt-like sheet having an arc-shaped cross section and having a width slightly larger than half of the inner circumference of the trough of the tube is integrated over the entire length only in the lower half of the inner periphery of the trough of the resin tube. This belt-like sheet forms a fluid passageway with no irregularities in the tube axis direction.

(Function) According to the bellows tube configured in this way, the lower half of the inner circumferential surface is formed into a smooth fluid passage by the belt-shaped sheet having an arcuate cross section. Like a tube, it becomes a passageway with low flow resistance and enables smooth circulation.

Furthermore, since the belt-like sheet is integrated only in the lower half of the bellows tube, when the bellows tube is bent upward, a tensile force acts on the upper half, and the lower half of the bellows tube is bent upward. Compressive force acts on the upper half, but since the belt-like sheet is not provided in the upper half, the wavy surface that forms this part stretches freely, while on the lower half, the wavy surface expands due to the compressive force. As the sheet contracts, the belt-like sheet portion between the adjacent troughs deforms inwardly and contracts, and is easily bent.

Furthermore, when the bellows tube is bent downward, the corrugated surface of the upper half where the band sheet is not provided contracts, making the bending easier. While having a certain free bending function, it is possible to enable the smooth flow of fluid as described above.

(Example) Next, an example of the present invention will be described based on FIGS. 1 to 6. In Figures 1 to 3,
1 is a bellows tube according to the present invention, which includes a tube body 2 similar to a conventional bellows tube, which has a corrugated cross-sectional shape in the tube axis direction and has annular peaks 3 and troughs 4 alternately formed; It consists of a band-shaped sheet 5 extending in the tube axis direction and integrated only in the lower half of the inner circumferential surface of each valley portion 4 of the tube body 2. The belt-shaped sheet 5 has a width slightly larger than half of the inner circumference length of the trough 4 of the tube body 2, and is located in a space surrounded by a horizontal plane connecting the belt-shaped sheet 5, which has an arcuate cross section, and its side edges. Thus, a fluid passage 6 with no unevenness in the tube axis direction is formed within the tube body 2.

According to the bellows pipe 1 having such a configuration, the fluid passage 6 without irregularities is formed in the bellows-shaped pipe body 2, so if the fluid passage 6 is placed at the lower level and the piping is done,
Even when fluid containing solids such as wastewater flows, it flows smoothly, and the solids do not get caught in the valleys 4 on the inner circumference of the pipe body 2 and remain or accumulate, so that the flow is smooth. It has low distribution resistance and is also hygienic.

Next, an example of the method and apparatus for manufacturing the bellows tube 1 will be explained with reference to FIGS. 4 to 6. In FIG. 4, reference numeral 11 denotes a nozzle of the extruder main body, from the tip of which uncured synthetic resin is extruded in a cylindrical shape. In front of the nozzle 11, a molding section 12 is arranged, which is constituted by an upper mold 13 and a lower mold 14, which are formed by endlessly connecting a large number of unit division molds. The upper mold 13 and the lower mold 14 are configured to rotate on a moving path along the axial extension of the nozzle 11, and to move in close contact with each other on this moving path. A mold surface 15 corresponding to the outer shape of the bellows-shaped tube body 2 to be formed is formed on the surface. The nozzle 11 is configured to supply pressurized gas into the interior of an extruded cylindrical synthetic resin, and a string-like body 16 extends from the tip of the nozzle 11 to prevent the pressurized gas from escaping. , a plurality of plugs 1 which are slidably fitted to the inner periphery of the bellows tube 1 at one end thereof.
7 is installed. In this way, the cylindrical uncured resin extruded from the nozzle 11 is pressed against the mold surfaces 15 of the upper mold 13 and the lower mold 14 by the pressure gas and hardened, thereby forming the tube body 2. At the same time, a strip sheet 5 is fed out from the nozzle 11 (see FIG. 6), and this strip sheet 5 is fed to the mold surface 1.
The bullet-shaped pressing member 18 attached to the string-like body 16 presses against the inner periphery of the trough of the tube body 2 which is pressed against the tube body 5 and is not completely hardened, and the two are fixed together. be.

To explain in more detail a specific example of the configuration of the nozzle 11, in FIGS. 5 and 6, 21 is a hollow nozzle body attached to the extruder body 19 at a flange 21a at the base end thereof, Once upon a time, the diameter gradually became narrower. 20 is a screw of the extruder main body. Inside the nozzle body 21 is a core 22.
A cylindrical synthetic resin passage 23 whose cross-sectional area and diameter gradually decrease is formed between the inner surface of the nozzle body 21 and the outer surface of the core 22, and the synthetic resin passes through this synthetic resin passage 23 to the nozzle. 11 is extruded into a cylindrical shape from the tip. A large-diameter support portion 24 is formed at the base end of the core 22, and this support portion 2
The core 22 is supported by tightly fitting the cylindrical portion 4 into the cylindrical portion 25 near the base end of the nozzle body 21 .
Reference numeral 26 represents a resin passage hole that passes through the support portion 24 . Reference numeral 27 denotes a shaft hole that passes through the axis of the core 22 and opens at the tip, and the base end thereof has a pressurized gas supply hole 28 and a string-like body drawer that penetrates the support portion 24 and the cylindrical portion 25 of the nozzle body 21 in the radial direction. It communicates with hole 29. 30 is a synthetic resin channel having an arcuate cross section for forming the strip sheet 5, and the core 22 is connected to its support portion 24.
It is formed penetrating from the tip to the tip, and its cross-sectional area gradually decreases toward the tip.

In such a nozzle 11, the extruder main body 1
When the synthetic resin is continuously extruded in step 9, the synthetic resin is extruded in a cylindrical shape from the nozzle tip through the cylindrical synthetic resin passage 23, and at the same time, the synthetic resin is extruded in a band shape inside through the synthetic resin passage 30. being pushed out. The extruded cylindrical synthetic resin is inserted into the shaft hole 2.
The synthetic resin is pressed against the mold surface 15 by the pressurized gas supplied through the tube 7 to form a tube body 2 having a corrugated cross section in the tube axis direction, and the synthetic resin extruded into a band shape is completely removed by the pressing member 18. It is pressed against the inner circumferential surface of the valley portion of the unhardened tube body 2 and is fixed integrally therewith.

In addition, in the above embodiment, the belt-shaped sheet 5 was formed at the same time as the tubular body 2 was formed, but
Nozzle 11 using a belt-shaped sheet manufactured separately.
Alternatively, the liquid may be supplied into the tube body 2 from outside through the core 22.

Further, in the above embodiments, the bellows tube 1 having a circular cross-sectional shape is illustrated, but the present invention is not limited to a circular cross-section, and can be applied to a bellows tube having any cross-sectional shape. For example, as shown in FIG. As shown, a bellows tube 31 having an oval cross section can also be configured. This bellows tube 3
1 is a tube body 3 having an oval cross section and a corrugated cross section in the tube axis direction.
A band-shaped sheet 5 is integrated with the inner periphery of the trough portion on the small diameter side of 2 to form a fluid passage 36 having a nearly V-shape. According to this bellows tube 31, the flow resistance can be reduced even when the fluid flow rate is small.

According to the bellows tube of the present invention, as is clear from the above description, the cross-sectional shape in the tube axis direction is waveform, and the troughs of the synthetic resin tube have alternating annular peaks and troughs. Only in the lower half of the circumference, a synthetic resin band sheet with an arcuate cross section and a width slightly larger than half of the inner circumference of the trough of the tube body is integrated over the entire length, and this band sheet allows the tube to be Since it forms a fluid passage with no irregularities in the axial direction, even though it is a bellows tube, the band-shaped sheet with an arcuate cross section provided in the lower half of the inner peripheral surface provides the same flow resistance as a normal tube. A small flow path can be obtained, and even when solid matter is mixed in the fluid, it can be made to flow smoothly, and it can be effectively applied to drain pipes and the like.

Furthermore, since the belt-like sheet is integrated only in the lower half of the bellows tube, when the bellows tube is bent upward, a tensile force acts on the upper half, and the lower half of the bellows tube is bent upward. Compressive force acts on the upper half, but since the belt-like sheet is not provided in the upper half, the wavy surface that forms this part stretches freely, while on the lower half, the wavy surface expands due to the compressive force. As the sheet contracts, the belt-like sheet portion between the adjacent troughs deforms inwardly in accordance with the contraction and contracts integrally, making it possible to easily bend the bellows tube downward. In this case, the wavy surface of the upper half on which the belt-like sheet is not provided contracts and can be easily curved.

Therefore, in addition to providing the free bending function that is an inherent characteristic of the bellows pipe, smooth fluid circulation as described above is enabled, and piping is facilitated.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
Fig. 1 is a cross-sectional view, Fig. 2 is a sectional view taken along line A-A in Fig. 1, Fig. 3 is a partially omitted exterior front view, Fig. 4 is a schematic configuration diagram of the manufacturing equipment, and Fig. 5 is a nozzle configuration. Partial cross-sectional view, Figure 6 is an enlarged cross-sectional view of main parts of the manufacturing process, Figure 7 is a partial cross-sectional view.
The figure is a cross-sectional view of another embodiment. 1, 31... Bellows tube, 2, 32... Tube body, 3...
... Mountain part, 4 ... Valley part, 5 ... Band-shaped sheet, 6, 3
6...Fluid passage.

Claims (1)

[Scope of utility model registration request] Only in the lower half of the inner periphery of the trough of a synthetic resin tube whose cross-sectional shape in the tube axis direction is waveform and in which annular peaks and troughs are formed alternately, the length of the inner periphery of the trough of the tube is determined. A bellows tube, characterized in that a belt-like sheet made of synthetic resin having an arc-shaped cross section and having a width slightly larger than half of the width of the pipe is integrated over the entire length, and this belt-like sheet forms a fluid passageway with no irregularities in the direction of the pipe axis. .