JP2005315055A - Tube with spiral guiding passage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently attenuate the energy of inflow water such as sewerage by producing a stable vortex even in the case of treatment with a small head. <P>SOLUTION: In a tube 1 with a spiral guiding passage having a central tube 4 provided in a straight tube body 2 erected approximately vertically and the spiral guide passage 3 formed between the central tube 4 and the internal circumference of the tube body 2, when the inner diameter of the tube body 2 is represented by D, the outer diameter of the central tube 4 is represented by d and the spiral pitch of inclination of the spiral guiding passage 3 is represented by P, the outer diameter d is D/8 to D/4 and the spiral pitch P is D/2 to 7D/10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pipe with a spiral guide channel suitable for use in a natural flow vertical sewer pipe.

  In places where the surface gradient is steep, manholes are usually installed at appropriate intervals, and stepped sewers are formed in which steps are formed in the pipelines between the manholes. However, such a stepped sewer is not easy to construct and has a problem that construction costs are high because the construction period is long.

  Therefore, in place of the stepped sewage channel, a method of attenuating sewage flowing into the manhole by installing a pipe with a spiral guide channel (drop shaft) in the manhole has been implemented (for example, Patent Documents). 1).

  For example, as shown in FIG. 4 (A), the pipe with the spiral guide path is formed in a straight pipe main body (vertical pipe main body) 202, an upper spiral guide path (upper spiral guide plate) 231 and a lower spiral guide path (lower part). A spiral guide plate) 232 is installed above and below at a predetermined interval, and an intermediate guide passage 233 having no spiral guide plate is provided between the upper and lower spiral guide passages 231 and 232 (a hollow drop shaft). There is. As shown in FIG. 4B, a spiral guide path (spiral guide plate) 303 extending from the upper part of the pipe to the lower part of the pipe at an equal pitch is installed in a straight tubular pipe main body (vertical pipe main body) 302 ( (Equal pitch drop shaft). The pipes 201 and 301 with spiral guide paths are provided with central tubes 204 and 304 for discharging air upward at the centers of the spiral guide paths 231 and 303 (centers of the pipe main bodies).

In such a pipe with a spiral guide path, the sewage flowing into the pipe body from the upper inflow pipe flows down spirally in the pipe body, so that a vortex is generated and the energy of the inflow sewage is attenuated. And the sewage which became the attenuation | damping state flows out outside from the outflow pipe provided in the lower end part of the pipe main body. Therefore, if the pipe with the spiral guide path is installed in the manhole, damage to the manhole bottom can be prevented. It is also possible to reduce the scattering of sewage and the generation of noise and odor.
JP-A-8-41915

  By the way, a pipe with a spiral guideway (spiral guideway type drop shaft) is intended to be installed in a manhole for high drop / mid drop joints. Drop shafts (mid-head type) are generally widely used, but recently, even in low-head manholes, there is a demand for attenuation of sewage energy and suppression of air entrainment.

  The present invention has been made in view of such a situation, and can generate a stable vortex flow even in a low head treatment, and can efficiently attenuate the energy of inflow water such as sewage flowing into a manhole or the like. The purpose is to provide a tube with a spiral guideway.

  The present invention can cope with a low drop in which the distance between the drop and the pipe bottom of the outflow pipe provided at the lower end of the pipe main body is not more than 3.5 times the inner diameter of the pipe main body. The present invention relates to a spiral guide path having a center tube provided in a straight tubular tube body (vertical tube body), and a spiral guide path formed between the center tube and the inner peripheral surface of the tube body. It is a tube, and the distance of one pitch of the outer diameter of the center tube and the spiral pitch of the spiral guide path is made smaller than the conventional spiral guide path type drop shaft (for high head processing) In addition, the outer diameter of the central tube is reduced.

  Specifically, in the conventional spiral guide path type drop shaft, if the diameter (inner diameter) D of the pipe body is 1D, the distance of the pitch of the spiral guide path is 4D / 5 (spiral inclination angle 14.3 °). When the outer diameter of the center tube is D / 3, the inner flow rate is 2,000 mm, the head height is 4 m, the flow velocity in the spiral guideway is 11.65 m / s, and the flow rate is high, and the air entrainment obtained from the experiment tends to be large. It was.

  On the other hand, in the present invention, in order to suppress the air entrainment amount, the present inventors have found that the air entrainment amount is suppressed by reducing the flow velocity by reducing the helical inclination angle. And in order to increase the flow rate which can be flowed in, the diameter of the central tube diameter was reduced while ensuring the air discharge function, and both the low head and the air discharge function could be achieved. Making the spiral inclination angle gentle means that the distance between the pitches of the spiral is made small, processing with a low drop is possible, and the amount of air entrainment can be reduced. In the pipe with a spiral guide path of the present invention, the distance of one pitch of the spiral guide path is D / 2 to 7D / 10, and the outer diameter of the central cylinder is D / 8 to D / 4. If the distance of one pitch of the spiral guide path is less than D / 2, it is difficult to secure the flow rate, and if it exceeds 7D / 10, the air entrainment amount increases. The outer diameter of the central cylinder is set to D / 8 to D / 4 in order to ensure a space for effectively discharging air from the central cylinder and to allow the design flow rate to flow down.

  As described above, the outer diameter of the central cylinder is reduced to increase the flow path width (the width of the spiral guide plate), and the distance of one pitch of the spiral guide path is made smaller than that of the conventional spiral guide path type drop shaft. Thus, a stable vortex flow can be formed even in the low head treatment, and the energy of the inflow water such as sewage can be attenuated efficiently.

  In the pipe with a spiral guide path of the present invention, it is preferable that the inner diameter of the outflow pipe provided at the lower end of the pipe main body is 1/2 to 7/10 of the inner diameter of the pipe main body. If it is less than 1/2, there is a problem because it is difficult to secure the flow rate, and if it exceeds 7/10, there is a problem because the air entrainment amount increases. In the pipe with a spiral guide path according to the present invention, the distance H between the heads of the pipe bottom of the inflow pipe provided at the upper end of the pipe main body and the pipe bottom of the outflow pipe provided at the lower end of the pipe main body (see FIG. 1). ) Is preferably 1.5 to 3.5 times (1.5D to 3.5D) the diameter (inner diameter D) of the tube body.

  The present invention relates to a pipe with a spiral guide path in which a rib-shaped spiral guide path is provided on the inner peripheral surface of a straight tubular pipe body (vertical pipe body). Means are provided along the peripheral surface, and if the diameter (inner diameter) of the tube body is D, the width of the rib-shaped spiral guide path is D / 6 to D / 3, and the rib-shaped spiral guide path The helical pitch is 0.5D to 0.8D.

  In the pipe with a spiral guide path of the present invention, the distance H between the heads of the inflow pipe provided at the upper end of the pipe main body and the bottom of the outflow pipe provided at the lower end of the pipe main body is the pipe main body. The diameter (inner diameter D) is preferably 1.5 times to 4.5 times (1.5D to 4.5D).

  Here, it is preferable that the pipe body, the spiral guide path (spiral guide plate), the center tube, and the like constituting the pipe with the spiral guide path of the present invention are manufactured from a thermoplastic resin, a thermosetting resin, or the like. Examples of the thermoplastic resin include polyvinyl chloride resins, olefin resins such as polyethylene (PE) and polypropylene (PP), and methacrylic resins. Examples of the thermosetting resin include unsaturated polyester resins, vinyl ester resins, and epoxy resins. Furthermore, what reinforced these resin with fibers, such as an inorganic fiber, glass fiber, organic fiber, carbon fiber, aramid fiber, vinylon fiber, can also be used. In addition, it is also possible to use a resin, such as SMC (Sheet Molding Compound) or BMC (Bulk Molding Compound), in which a filler such as fiber, calcium carbonate or magnesium carbonate is filled.

  In addition, as a pipe body constituting a pipe with a spiral guide path, a glass fiber reinforced resin composite pipe having a three-layer structure in which glass fiber reinforced resin (FRP) is laminated on the inner peripheral surface and the outer peripheral surface of a mortar pipe, respectively. You may use, and you may shape | mold the spiral guide plate which comprises a spiral guide path with glass fiber reinforced resin. In this case, the tube body (including the center tube) and the spiral guide plate may be integrally formed by a hand layup method or the like.

  According to the present invention, in a tube with a spiral guide path having a center tube provided in a straight tube main body, and a spiral guide path formed between the center tube and the inner peripheral surface of the tube body, Decreasing the outer diameter of the central tube (1/8 to 1/4 of the inner diameter of the tube body) to increase the channel width (width of the spiral guide plate) and reducing the helical pitch of the spiral guide path (inner diameter of the tube body) Therefore, a stable vortex can be formed even in the low head processing, and the energy of the inflow sewage can be attenuated efficiently in the low head manhole. As a result, manhole durability is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an example of a pipe with a spiral guide path of the present invention. 2 is a cross-sectional view taken along the line XX of FIG.

  A pipe 1 with a spiral guide path in this example is a pipe (drop shaft) installed in a manhole for low head processing, and includes a pipe body 2 and a spiral guide path 3 and a central cylinder 4 disposed therein. I have. In this example, a glass fiber reinforced resin composite tube is used for the tube body 2, and the spiral guide path 3 (spiral guide plate 3a) is formed of glass fiber reinforced resin. The center tube 4 is a glass fiber reinforced resin pipe.

  The pipe body 2 is provided with an inflow pipe 2a and an outflow pipe 2b at the upper end and the lower end, respectively, and the distance between the bottom of the inflow pipe 2a and the bottom of the outflow pipe 2b is the drop shaft. The distance H is the head. A bottom plate 2c made of a material having wear resistance (for example, high molecular weight polyethylene resin) is provided at the bottom of the tube body 2. The central cylinder 4 is for exhausting upward the air contained in the sewage guided by the spiral guide path 3, and is arranged along the center of the pipe body 2.

  The spiral guide path 3 is configured by a spiral guide plate (spiral rotation number = 1 rotation) extending spirally in the vertical direction between the inner peripheral surface of the tube body 2 and the outer peripheral surface of the central tube 4. A guide plate 5 for guiding the sewage flowing into the pipe body 2 from the inflow pipe 2a in the rotation direction of the spiral guide plate is provided at the inlet portion of the spiral guide path 3 (starting end portion of the spiral guide plate). The guide plate 5 extends from the start end of the spiral guide plate to the top of the tube body 2. The spiral guide plate is integrally formed on the inner peripheral surface of the tube body 2 and the outer peripheral surface of the center tube 4 by a hand lay-up method.

  In the pipe 1 with a spiral guide path having the above structure, when the sewage that has entered the manhole (not shown) flows into the pipe body 2 through the inflow pipe 2a, the inflow sewage flows into the inner peripheral surface of the pipe body 2 and the guide plate. 5 and the like, flows in only one direction along the circumferential direction of the tube body 2 and flows into the spiral guide path 3. The sewage that has flowed into the spiral guide path 3 becomes a vortex in the spiral guide plate 3 a and flows down in the pipe body 2 to attenuate the energy. 2b is discharged to a downstream pipe (not shown).

  In this embodiment, if the diameter (inner diameter) of the tube main body 2 is D, the outer diameter d of the central cylinder 4 is D / 6 to D / 8, and the pitch P of the spiral guide path 3 (spiral guide plate 3a). Is 0.5D to 0.8D, and the outer diameter d of the central tube 4 is reduced more than a general spiral guide path type drop shaft (for high head processing) to reduce the channel width (width of the spiral guide plate 3a). It is characterized in that it is enlarged and the pitch P of the spiral guide path 3 is reduced. By adopting such a characteristic configuration, a stable vortex can be formed even in a low head treatment, and the inflow sewage Energy can be efficiently attenuated. Moreover, the distance H between the heads of the drop shaft can be set to 1.5D to 4.5D, and installation in a manhole for low head processing becomes possible. The rotation speed of the rib-shaped spiral guide plate 3a is not limited to one rotation, and may be two to three rotations as long as it is within a specified range of the head distance H.

  Furthermore, according to the pipe with the spiral guide path of this embodiment, there is also an advantage that the air entrainment ratio ([exhaust amount of air flowing out from the outflow pipe] / [inflow water amount]) can be kept low. The air entrainment rate is described below.

<About air entrainment rate>
-Air entrainment measuring device-
First, an air entrainment amount measuring apparatus used for measuring the air entrainment rate will be described with reference to FIG. An air entrainment measuring apparatus 101 shown in FIG. 3 includes a measurement tank 102 having a sealed structure in which an inflow pipe 102a and an outflow pipe 102b are provided at both ends, and a slit plate (movable up and down) provided at a downstream end of the measurement tank 102. Plate) 103, and an air extraction pipe 104 provided between the inflow pipe 102 a and the slit plate 103 and communicating with the upper part of the measurement tank 102. An open / close valve 105 is connected to the air extraction pipe 104, and a measurement rubber bag 106 is attached to the upper end portion.

-Measurement method of air entrainment rate-
When measuring the air entrainment rate of the pipe 1 with a spiral guide path shown in FIG. 1, as shown in FIG. 3, the outflow pipe 102b of the air entrainment amount measuring device 101 is connected to the outflow pipe 2b of the pipe 1 with the spiral guide path. At the same time, in a state where a water supply pipe (both not shown) having a diameter 150 connected to a flow valve and a flow meter is connected to the inflow pipe 2a of the pipe 1 with a spiral guide path, Water is supplied to the water supply pipe and supplied into the pipe 1 with the spiral guide path. The water that has flowed into the pipe 1 with the spiral guide path falls downward along the spiral guide path 3, and then returns to the water tank again from the outflow pipe 2 b at the bottom of the pipe body 2 through the air entrainment measuring device 101. .

In such a water supply system, water and air flowing out from the spiral guide passage-equipped pipe 1 are both swirled and flow into the air entrainment measuring apparatus 101, but the slit plate 103 at the end of the measuring tank 102 is placed below the water surface. By operating in this manner, air can be trapped in the measurement tank 102. The trapped air is collected in the measurement rubber bag 106 by opening the open / close valve 105 of the air extraction pipe 104 for a predetermined time, and the amount of exhaust air (L / s) per fixed time is measured. And the air entrainment rate is calculated | required by the following formula from the amount (L / s) of the inflow (L / s) of the water (air included) to the pipe | tube 1 with a spiral guideway with the amount of exhaust air.
Air entrainment rate = 100 × [exhaust air volume (L / s) / inflow volume (L / s)]

<About flow conditions>
・: Stable vortex flow is formed and there is little turbulence in the outflow area.
・: Swirl at the top is formed to some extent, but some turbulence is seen near the bottom.
×: Situation where the full water level is exceeded when the design flow is applied.

Example 1
In the pipe 1 with a spiral guide path having the structure shown in FIG.
Inner diameter D of pipe body 2 = 150 mm Outer diameter d of central cylinder 4 = 21 mm (D / 7)
Spiral pitch P = 90 mm (0.6 D) = tilt angle 10.8 °
Helix rotation speed (number of turns of the spiral guide plate 3a) = 1 rotation Head distance H = 300mm (2.0D)
Outflow pipe O = 75mm (0.5D)
The air entrainment ratio of the manufactured model was measured by the measuring method shown in FIG. However, the flow rate (inflow water amount) was 6.7 L / s.

(Example 2)
Example 1 was the same as Example 1 except that the outer diameter d of the central tube 4 was 18 mm (D / 8).
Example 3
Example 1 was the same as Example 1 except that the outer diameter d of the central tube 4 was 37 mm (D / 4).
Example 4
Example 1 was the same as Example 1 except that the helical pitch P = 75 mm (0.5 D) = tilt angle 9.05 °.
(Example 5)
Example 1 was the same as Example 1 except that the helical pitch P = 105 mm (0.7 D) = tilt angle 12.55 °.
(Example 6)
The same as Example 1 except that the outlet pipe was set to 60 mm (0.4 D).
(Example 7)
The same as Example 1 except that the outflow pipe was set to 120 mm (0.8 D).

(Comparative Example 1)
Example 1 was the same as Example 1 except that the outer diameter d of the central tube 4 was 50 mm (D / 3).
(Comparative Example 2)
Example 1 was the same as Example 1 except that the outer diameter d of the central tube 4 was 16 mm (D / 9).
(Comparative Example 3)
Example 1 was the same as Example 1 except that the helical pitch P = 60 mm (0.4D) = inclination angle 7.0 °.
(Comparative Example 4)
Example 1 was the same as Example 1 except that the helical pitch P = 150 mm (1.0 D) = inclination angle 17.8 °.
The measurement results are shown in Table 1 below.

以上の表１に示す結果から、螺旋案内路式ドロップシャフト（高落差処理用）において一般に使用されている設計資料に基づいて中心筒の外径及び螺旋ピッチ等を設定したモデル（比較例）では、空気連行率が４．５％を超えているのに対し、本発明の要件を満足するモデル（本発明の螺旋案内路付き管）では、空気連行率が４．５％以下に抑えることが可能であることがわかる。

From the results shown in Table 1 above, in the model (comparative example) in which the outer diameter of the central tube, the helical pitch, etc. are set based on the design materials generally used in the spiral guide type drop shaft (for high head processing) In the model satisfying the requirements of the present invention (pipe with spiral guideway of the present invention), while the air entrainment ratio exceeds 4.5%, the air entrainment ratio can be suppressed to 4.5% or less. It turns out that it is possible.

  The pipe with a spiral guide path of the present invention can be effectively used for attenuating the energy of inflow water such as sewage flowing into a low head type manhole.

It is a longitudinal section showing an example of a pipe with a spiral guide way of the present invention. It is XX sectional drawing of FIG. It is explanatory drawing of the measuring method of an air entrainment rate. It is a figure which shows typically the example of a pipe (with a spiral guideway) installed in the manhole of a high drop and a medium drop junction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe with spiral guide 2 Pipe body 2a Inflow pipe 2b Outflow pipe 2c Bottom plate 3 Spiral guide path 3a Spiral guide plate 4 Center tube 5 Guide plate

Claims (2)

An upper end of the tube body, wherein the tube body has a center tube provided in the straight tube body and a spiral guide path formed between the center tube and the inner peripheral surface of the tube body. The distance between the heads of the inflow pipe provided at the bottom and the bottom of the outflow pipe provided at the lower end of the pipe body is a low head of 3.5 times or less the inner diameter of the pipe body. The outer diameter of the central tube is 1/8 to 1/4 of the inner diameter of the tube body, and the inclination of the spiral guide path is 1/2 to 7 times the inner diameter of the tube body. A pipe with a spiral guideway, characterized in that it is / 10. The pipe with a spiral guide path according to claim 1, wherein an inner diameter of an outflow pipe provided at a lower end portion of the pipe main body is 1/2 to 7/10 of an inner diameter of the pipe main body.

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