JP2006177513A - Multi-stage bend for piping, and connecting method for resin pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-stage bend for piping, which can form a coupling member having a plurality of bending angles from one kind of a member. <P>SOLUTION: The multi-stage bend 1 for piping has a plurality of straight pipe sections 12a to 12e, and a plurality of bent sections 11a, 11b, 11c, and 11d. The adjacent straight pipe sections 12 are bent pipe-shaped joint members connected so that their center axes are crossed via the bent sections 11. In an other multi-stage bend 4, an electrically fusion-welded joint 5, in which a socket 51 inserted with a resin pipe 3 is provided and an electric heat wire 52 is buried in an inner surface of the socket, can be firmly fixed into the straight pipe section at one end. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin member for connecting a thermoplastic resin pipe used for buried pipes such as city gas and waterworks, and more specifically, a pipe for connecting a pipe having a bent portion of a predetermined angle. The present invention relates to a multistage bend for use and a resin pipe connecting method using the same.

  Pipes such as gas pipes and water pipes through which city gas flows, etc. are buried in the ground, so they are lightweight, have excellent workability, have great elongation, and have excellent earthquake resistance, such as polyethylene. A pipe made of (hereinafter referred to as a resin pipe) is used. As a method of connecting the resin pipe, use an electric fusion joint having a receiving port with a heating wire embedded on the inner peripheral surface side, and insert the end of the resin tube into the receiving port and then energize the heating wire. Generally, the joint inner peripheral surface and the outer peripheral surface of the resin pipe are fused and joined by generating heat.

  When connecting resin pipes embedded in the ground with a step, an electric fusion joint (for example, 45 ° elbow or 90 ° elbow) having a predetermined bending angle is used. In addition to this, in order to be able to form several types of joints from one type of member, the length of the straight pipe part on both sides of the bent part is made different, and the longer straight pipe part is connected to, for example, an electric A thermoplastic resin member has been proposed in which another member is butt-fused to a shorter straight pipe portion as a pipe insertion hole to be inserted into a fusion joint (see Patent Document 1).

  When burying pipes, prepare joints that match the bend angle of the pipe line described in the piping diagram, and start construction after preparing the required number. However, when there are other buried objects that are not shown in the piping diagram, there is a case where the piping needs to be bypassed. Accordingly, other buried objects are assumed in advance, and a plurality of bending joints with different bending angles are carried to the piping site to cope with them. In this method, even in the case of an elbow, for example, the bending angle is limited to several types (for example, 11.25 °, 22.5 °, 45 °, 90 °) in consideration of the manufacturing cost and storage space. Even if a bent joint is used, piping corresponding to all the bending angles cannot be performed. In addition, in order to connect the buried pipe at an arbitrary bending angle, a joint 6 (elbow) is formed between the resin pipes 3a, 3c and 3c, 3b buried in the ground as shown in FIG. ) Are joined to form a crank-shaped pipe line.

Japanese Unexamined Patent Publication No. 2003-247687 (pages 2 and 3, FIG. 1)

  However, even when extra bending joints can be carried and handled, extra bending joints are required, leading to an increase in the cost of piping members, and the connection structure shown in FIG. Since the short pipe 7 is used, there is a problem in that the piping cost increases due to the increase in the number of parts and the number of connecting steps. Furthermore, in order to form a crank-shaped pipe line, it is necessary to excavate deeply between the resin pipes 3a and 3b, and there is a problem that the piping cost further increases.

  Therefore, the objective of this invention is providing the multistage bend for piping which can form the joint member which has a some bending angle from one type of joint member.

  Another object of the present invention is to provide a resin pipe connection method capable of forming bent pipes having different bend angles at a low cost.

  In order to achieve the above object, the multistage bend for piping according to the present invention has a plurality of straight pipe portions made of thermoplastic resin and a plurality of bent portions, and the adjacent straight pipe portions are interposed via the bent portions. It is a bent joint member connected so that the central axes intersect.

  Moreover, in the multistage bend for piping according to the present invention, an electrofusion joint having a receiving port into which a resin pipe is inserted at one end of the cylindrical member and a heating wire embedded in the inner surface of the receiving port is fixed. May be.

  Moreover, in the multistage bend for piping of the present invention, it is preferable that a marking portion capable of visually recognizing the bending angle is formed on the outer peripheral surface of each straight pipe portion.

  In the resin pipe connecting method of the present invention, n (n: an integer of 3 or more) straight pipe portions made of a thermoplastic resin are connected via (n-1) bent portions made of a thermoplastic resin. A bent tubular joint member is prepared, a joint member including 2 to n straight pipe portions is cut off from the joint member, and a resin pipe is fusion bonded to both ends of the joint member. It is.

  In the resin pipe connecting method of the present invention, it is preferable that the resin pipe is fusion-bonded to both end portions of the joint member via an electric fusion joint.

  According to this invention, since it is set as the curved tubular joint member in which the curved part was provided between the straight pipe parts, the joint member which has a some bending angle can be taken out from one type of joint member.

  In addition, by providing an electrofusion joint at one end of the curved tubular joint member connected in the axial direction, it becomes possible to perform the scraping operation of the resin pipe only at one end, thereby reducing the man-hour of the fusion operation. be able to.

  Furthermore, by providing a marking portion that displays the bending angle on the outer peripheral surface of each straight pipe portion, the connection work can be quickly performed.

  According to the present invention, if one type of joint member is prepared, bent pipes having different bending angles can be formed at low cost by cutting out a member having a predetermined bending angle therefrom.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a half sectional view of a multistage bend for piping according to an embodiment of the present invention, FIG. 2 is a front view showing a connection state at a maximum bending angle, and FIG. 3 is a front view showing a connection state at a minimum bending angle. FIG.

  As shown in FIG. 1, a multistage bend 1 for piping (hereinafter referred to as multistage bend) is formed between a plurality of straight pipe portions 12 (12a... 12e) made of thermoplastic resin having the same overall length L and outer diameter D. The adjacent straight pipe portions 12 are spigot type joint members that are continuously connected via the bent portions 11 (11a... 11d). The straight pipe portion 12 and the bent portion 11 are integrally formed, and it is preferable to use a polyolefin-based resin such as polyethylene or polybutene as the thermoplastic resin.

The multi-stage bend 1 is integrally formed by softening a straight pipe made of a thermoplastic resin close to the melting point, pushing it into a mold in which a product-shaped space is formed, and then cooling and solidifying it. The The multi-stage bend 1 of FIG. 1 includes n-1 bent portions 11 (11a... 11d) between n straight pipe portions 12 (12a... 12e). the angle between the central axis _{X 2} of the center axis _{X 1} and the straight pipe portion 12e (hereinafter referred to as the skew angle beta) is represented by (n-1) × α. (Α indicates the bending angle of the adjacent straight pipe portions 12) Further, the bending angle (0 of each straight pipe portion with respect to the straight pipe portion 12a on one end side (left side) is provided on the outer peripheral surface of the straight pipe portions 12b. Marking portions 13 (13a... 13e) indicating 11.25 (α) °, 22.5 (2α) °, 33.75 (3α) °, 45 (4α) °) are provided. It is desirable that the marking unit 13 be printed by a marking type printing means such as hot stamp type printing. Further, in order to allow the end of the multistage bend 1 to be inserted into the receptacle of the electric fusion joint 2, the length L of each straight pipe portion 12 is not less than the insertion depth into the electric fusion joint 2. Is set to In the present embodiment, the same value is set for the bend angle α of the adjacent straight pipe sections 12, but according to the present invention, the bend angles α are α ₁ , α ₂ , α ₃ ... Α _(n− Different values can be set as in ₁₎ .

  By using the multistage bend 1 described above, a bent pipe having a bent angle β = 4α shown in FIG. 2 can be connected by the following procedure. Since the end portion 31a of the resin tube 3a, the end portion 31b of the resin tube 3b, and both end portions 14 and 15 of the multistage bend 1 are inserted into the receiving ports 21a and 21b of the electric fusion joints 2a and 2b, In order to clean, a scraping operation is performed using, for example, a canna type tool. Thereafter, by inserting the one end portion 14 of the multistage bend 1 and the end portion 31a of the resin tube 3a into the socket-type electric fusion joint 2a and energizing the heating wire 22a embedded in the inner peripheral surface of the receiving port 21a, The inner peripheral surface of the electric fusion joint 2a, the one end portion 14 of the multistage bend 1, and the end portion 31a of the resin pipe 3a are fusion bonded. The other end 15 of the multistage bend 1 and the end 31b of the resin tube 3b are also inserted into the socket-type electric fusion joint 2b in the same manner as described above, and the heating wire 22b embedded in the inner peripheral surface of the receiving port 21b is energized. By doing so, fusion bonding can be performed.

  In the present invention, a joint member having a plurality of bending angles β can be obtained from the multistage bend 1 described above. For example, in the case of forming a joint member having a bending angle β = α, the multi-stage bend 1 shown in FIG. 1 is cut at a boundary portion between the straight pipe portion 12b and the bending portion 11b, so that a pair of pairs as shown in FIG. What is necessary is just to produce the 1 step | paragraph bend which has the bending part 11a between the straight pipe parts 12a and 12b. Even when this one-stage bend is used, the resin pipes 3a and 3b can be connected to both ends of the first-stage bend through the electric fusion joints 2a and 2b in the same procedure as in the case of the bending angle 4α described above. it can.

  When a joint member having a bending angle β = (n−1) × α (n = 4 or 3) is produced from the multistage bend 1, the nth straight pipe from the left end of the multistage bend 1 shown in FIG. What is necessary is just to cut | disconnect the boundary part of the part 12 and the bending part 11, and cut | disconnect the joint member which has the n-1 bending part 11 between the n pieces of straight pipe parts 12. FIG. According to this joint member, the resin pipe can be connected in the same procedure as described above.

  FIG. 4 is a half sectional view showing a bent pipe using a multistage bend according to another embodiment of the present invention, and the same functional parts as those of the multistage bend shown in FIG. 1 are denoted by the same reference numerals. The multistage bend 4 has a receiving port 51 into which the pipe end portion 31a of the resin pipe 3a is inserted instead of the straight pipe portion 12a on the one end side portion 14 of the multistage bend 1 shown in FIG. This is a multi-stage bend of a single receiving type in which the electric fusion joint 5 in which the heating wire 52 is embedded is connected at the connection portion 16. The other parts are the same as those in FIG.

  According to the multistage bend 4 shown in FIG. 4, since the electric fusion joint 5 is provided on one end side in advance, the multistage bend 1 shown in FIG. 15) The scraping operation performed in 15) can be performed only at one place (end 15), and therefore the number of man-hours required for fusion bonding can be reduced.

  In the multistage bend according to the above-described embodiment, a plurality of straight pipe portions and bent portions are integrally formed, but the plurality of straight pipes are butted together so that the central axes intersect, and joined by, for example, butt fusion By doing so, a bent portion may be formed. Thus, the multistage bend of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

It is a half sectional view of a multistage bend concerning an embodiment of the invention. FIG. 2 is a half cross-sectional view illustrating an example of a bent pipe using the multistage bend of FIG. 1. FIG. 6 is a half sectional view showing another example of a bent pipe using the multistage bend of FIG. 1. It is a half sectional view showing bent piping using a multistage bend according to another embodiment of the present invention. It is a front view which shows the conventional bending piping.

Explanation of symbols

1, 4: Multistage bends 11a, 11b, 11c, 11d for piping: Bent portions 12a, 12b, 12c, 12d, 12e: Straight pipe portions 13a, 13b, 13c, 13d, 13e: Marking portions 14, 15: End portions 16 : Connection part 2 (2a, 2b), 5: electrofusion joint 21a, 21b, 51: receiving port 22a, 22b, 52: heating wire 3a, 3b, 3c: resin pipe 31a, 31b: pipe end part 6 (6a) 6b, 6c, 6d): Joint 7 (7a, 7b, 7c): Short pipe

Claims (5)

It has a plurality of straight pipe portions made of thermoplastic resin and a plurality of bent portions, and the adjacent straight pipe portions are bent tubular joint members that are connected so that the central axes intersect with each other via the bent portions. A multi-stage bend for piping. 2. The electric fusion joint having a receiving port into which a resin pipe is inserted and having an electric heating wire embedded in the inner surface of the receiving port is fixed to the straight pipe portion on one end side. Multistage bend for piping as described. The multistage bend for piping according to claim 1 or 2, wherein a marking portion for displaying a bending angle is formed on an outer peripheral surface of each straight pipe portion. Preparing a bent tubular joint member in which n (n: an integer of 3 or more) straight pipe portions made of a thermoplastic resin are connected via (n-1) bent portions made of a thermoplastic resin, A method for connecting resin pipes, comprising: cutting off a joint member including 2 to n straight pipe parts from the joint member, and fusing and joining the resin pipes to both ends of the joint member. The resin pipe connection method according to claim 4, wherein the resin pipe is fusion bonded to both ends of the joint member via an electric fusion joint.

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