JP2005147171A - Antinoise double pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antinoise double pipe with a sleeve having a smaller outer diameter, preventing noises due to a water hammer phenomenon. <P>SOLUTION: The double pipe having a liquid feed pipe 2 inserted into the sleeve 1 comprises a cushioning material 4 formed of a flexible band or string body creased in the direction of reducing the width and laid between the sleeve 1 and the liquid feed pipe 2 in the state that the width is a half of length of the outer periphery of the liquid feed pipe 2 or smaller. The cushioning material 4 suppresses the movement of the liquid feed pipe 2 in the sleeve 1. The inner diameter of the sleeve 1 is smaller enough to prohibit the insertion of the flexible cushioning material in the state of being wound on the outer periphery of the liquid feed pipe 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a noise prevention type double pipe.

  In recent years, a so-called sheath pipe header construction method has been widely adopted as a construction method for laying pipes for water supply and hot water supply in buildings. In the sheath pipe header construction method, a double pipe is used in which a plastic liquid feeding pipe is inserted inside a plastic sheath pipe (usually a flexible corrugated pipe). In such a double pipe, when the faucet is suddenly closed and the water hammer (water hammer) phenomenon occurs, the liquid feed pipe is exposed in the sheath pipe, and the liquid feed pipe collides with the inner surface of the sheath pipe. There may be noise.

As means for preventing such noise due to the water hammer phenomenon, as shown in FIGS. 3 and 4, an elastic cushioning material 3 is provided between the sheath tube 1 and the liquid feeding tube 2, as shown in FIG. It is known to use a double pipe interposed so as to cover almost the entire circumference (see, for example, Patent Document 1). If such a double pipe is used, even if the water hammer phenomenon occurs, the liquid feed pipe 2 does not collide with the inner surface of the sheath pipe 1, so that the generation of noise can be prevented. This type of noise-preventing double pipe has already been put into practical use, and as the cushioning material 3, for example, a foamed plastic sheet is used.
Japanese Patent No. 2934722

  The conventional noise prevention type double pipe as described above is assembled by inserting the liquid feeding pipe into the sheath pipe while winding the buffer material around the outer circumference of the liquid feeding pipe. The buffer material has a thickness of at least about 1 to 2 mm in order to have a practical buffer action. Therefore, the inner diameter of the sheath tube needs to be sufficiently larger than the outer diameter of the liquid feeding tube so that the buffer material can be inserted without difficulty while being wound around the liquid feeding tube. As a result, the outer diameter of the sheath pipe must be large for the nominal diameter of the double pipe (the inner diameter of the liquid feed pipe). Specifically, for example, in the case of a double pipe having a nominal diameter of 10 mm, the outer diameter of the liquid feed pipe is 13 mm, and the difference between the outer diameter of the liquid feed pipe and the inner diameter of the sheath pipe is secured to 9 mm, Is 22 mm, and the outer diameter of the sheath tube is 27.5 mm. Thus, it is difficult to reduce the diameter of the double pipe.

  In recent years, the construction space has become narrower in order to make the living space as large as possible, and in order to cope with such a narrow piping space, double pipes with as small a sheath diameter as possible are required. Desired.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a noise-preventing double pipe having a sheath outer diameter smaller than a nominal diameter.

  In order to achieve the above-mentioned object, the noise prevention type double pipe of the present invention has flexibility between the sheath pipe and the liquid feed pipe in the double pipe in which the liquid feed pipe is inserted into the sheath pipe. The movement of the liquid feeding pipe in the sheath pipe is made by interposing a cushioning material formed by brazing the band-like body or string-like body in the reduced width direction in a state where the width is half or less of the outer peripheral length of the liquid feeding pipe. It is characterized by suppressing.

  Whereas a conventional noise-preventing double pipe wraps a buffer material around the entire circumference of the liquid feed pipe, the present invention provides a narrow band or string-like body between the sheath pipe and the liquid feed pipe. It is intended to suppress the liquid feeding tube from violating in the sheath tube. According to the present invention, it is impossible to prevent a part of the outer periphery of the liquid feeding tube from coming into contact with the inner surface of the sheath tube, but the space for inserting the cushioning material can be small, so the inner diameter of the sheath tube and the liquid feeding tube can be reduced. By making the difference from the outer diameter of the pipe much smaller than before, a noise suppression effect equivalent to or higher than that of the conventional one can be obtained. And even if the nominal diameter of the same liquid feeding pipe is the same, the outer diameter of a sheath pipe | tube can be made small and the adaptability to a narrow piping space improves.

  In particular, a brazed plastic tape can be suitably used as the cushioning material. A thin plastic tape stretched in the longitudinal direction is commercially available, for example, as a packing string tape, and has high strength, good slipperiness, and is inexpensive. Some of these plastic tapes are brazed in advance in the direction of width and formed into a string shape, and there are no band-like ones. When it is inserted, the width is naturally reduced and brazed, and a suitable buffering property is exhibited.

  In the present invention, in order to suppress the noise caused by contact between the sheath tube and the liquid feed tube when the water hammer phenomenon occurs, to the extent that most people do not care, the inner diameter of the sheath tube and the outer diameter of the liquid feed tube It is preferable to make the difference between and 2 mm or less. More preferably, the difference between the inner diameter of the sheath pipe and the outer diameter of the liquid feeding pipe should be 1 mm or less. In this way, generation of noise can be substantially prevented. However, if the difference between the inner diameter of the sheath tube and the outer diameter of the liquid feeding tube is made too small, it becomes difficult to insert the liquid feeding tube and the buffer material together in the sheath tube. It is practical to do.

  According to the noise-preventing double pipe of the present invention configured as described above, a flexible belt-like body or string-like body is brazed in the width reducing direction between the sheath pipe and the liquid feeding pipe. The gap between the inner diameter of the sheath pipe and the outer diameter of the liquid feed pipe is markedly greater than before by interposing the cushioning material formed and making the width of the cushioning material less than half of the outer circumference of the liquid feed pipe Can be small. Thereby, the movement of the liquid feed pipe in the sheath pipe is suppressed, and the noise caused by the contact between the sheath pipe and the liquid feed pipe when the water hammer phenomenon occurs can be suppressed sufficiently small. In addition, since the outer diameter of the sheath tube can be made smaller than the conventional diameter for the liquid pipe with the same nominal diameter, the cost of the sheath tube can be reduced and the compatibility with a narrow piping space is also improved. To do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 show an embodiment of the present invention. This noise prevention type double pipe includes a sheath pipe 1 made of a corrugated plastic pipe, a liquid feed pipe 2 made of a cross-linked polyethylene straight plastic pipe inserted inside, a sheath pipe 1 and a liquid feed pipe 2 And a cushioning material 4 made of brazed plastic tape interposed in the tube length direction.

  The nominal diameter of the noise prevention type double pipe is determined by the inner diameter of the liquid feed pipe 2, but when the liquid feed pipe 2 is used as a reference, in the noise prevention type double pipe of the present invention, the inner diameter of the sheath pipe 1 corresponds to the sheath. The liquid feed tube 2 cannot be inserted into the tube 1 in a state where the elastic buffer material 3 is wound around the outer periphery as in the conventional case (FIGS. 3 to 4), but with the thin buffer material 4 having flexibility. It is set to be small enough to be inserted. Thus, when the difference between the inner diameter of the sheath tube 1 and the outer diameter of the liquid feeding tube 2 is reduced, the range in which the liquid feeding tube 2 can move within the sheath tube 2 is reduced.

  The cushioning material 4 is obtained by brazing a thin plastic tape stretched in the longitudinal direction in the reduced width direction. As shown in FIG. 1, the width of the buffer material 4 is not more than half of the outer peripheral length of the liquid feeding tube 2. This type of plastic tape is commercially available, for example, as a packing string tape made of polypropylene, which has high strength, good slipperiness, and is inexpensive. In addition, a polyester tape or polyethylene tape having a thickness of about 10 μm to 100 μm can be used as the buffer material 4. The plastic tape as described above includes a string-like shape that has been brazed in the width direction in advance and a belt-like shape that does not have a wrinkle. When it is inserted into the sheath tube 1 together with the liquid feeding tube 2 by bonding or the like, it is pulled in the tube length direction, the width is naturally reduced, and it is properly brazed.

  When such a buffer material 4 is interposed between the sheath tube 1 and the liquid feed tube 2, the liquid feed tube 2 is eccentric in the sheath tube 1, and the range of movement in the sheath tube 1 is further reduced. As a result, even if the water hammer phenomenon occurs and the liquid feed tube 2 is about to be violated in the sheath tube 1, the liquid feed tube 2 is almost undisturbed. It becomes small and generation | occurrence | production of noise can be prevented substantially.

  According to the experiment, when the difference between the inner diameter of the sheath tube 1 and the outer diameter of the liquid feeding tube 2 is 2 mm and the cushioning material 4 made of brazed plastic tape as described above is interposed, a water hammer phenomenon has occurred. Occasionally, a slight contact sound was generated between the sheath tube 1 and the liquid feed tube 2, but it was suppressed to the extent that it was hardly felt as noise. Also, if the difference between the inner diameter of the sheath tube 1 and the outer diameter of the liquid feeding tube 2 is 1.5 mm and the buffer material 4 is interposed, the contact sound when the water hammer phenomenon occurs is heard unless it is carefully heard. It was so small. Further, if the difference between the inner diameter of the sheath tube 1 and the outer diameter of the liquid feeding tube 2 is set to 1 mm and the buffer material 4 is interposed, the contact sound when the water hammer phenomenon occurs is hardly audible to human ears. It was confirmed that noise can be substantially prevented.

  Table 1 shows the pipe diameters of the sheaths 1 that are preferable for each nominal diameter. The plastic tape used for the buffer material 4 is made of polyethylene and has a width of about 50 mm and a thickness of 10 μm without wrinkles. For comparison, the pipe diameter of a conventional noise prevention type double pipe (type of FIGS. 3 to 4) is also shown.

表１に示した本発明の騒音防止型二重配管は、いずれのサイズにおいても、ウォーターハンマー現象が起きたときの接触音が、従来の騒音防止型二重配管と同様に、人間の耳では殆ど聞き取れない程度に抑制された。そして、表１から明らかなように、本発明によると、さや管１の外径を従来のものよりも格段に小さくすることができた。

The noise-preventing double pipe of the present invention shown in Table 1 shows that the contact noise when the water hammer phenomenon occurs in any size is similar to the conventional noise-preventing double pipe in the human ear. Suppressed to an almost inaudible level. As can be seen from Table 1, according to the present invention, the outer diameter of the sheath tube 1 could be made much smaller than the conventional one.

It is sectional drawing of the pipe diameter direction which shows embodiment of the noise prevention type | mold double piping which concerns on this invention. It is sectional drawing of the pipe length direction which shows embodiment of the noise prevention type | mold double piping which concerns on this invention. It is sectional drawing of the pipe diameter direction which shows the conventional noise prevention type | mold double piping. It is sectional drawing of the pipe length direction which shows the conventional noise prevention type | mold double piping.

Explanation of symbols

1 sheath tube 2 liquid feeding tube 4 cushioning material

Claims (3)

  In a double pipe that inserts a liquid feeding pipe into a sheath pipe, a cushioning material is formed by brazing a flexible band-like body or string-like body in the reduced width direction between the sheath pipe and the liquid feeding pipe. A noise-preventing double pipe characterized in that the movement of the liquid feed pipe in the sheath pipe is suppressed by interposing it in a state where the width is not more than half of the outer peripheral length of the liquid feed pipe.   The noise-preventing double pipe according to claim 1, wherein the cushioning material is brazed plastic tape.   The noise-preventing double pipe according to claim 1, wherein the difference between the inner diameter of the sheath pipe and the outer diameter of the liquid feeding pipe is 2 mm or less.

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