JP2000130659A - Pipe connecting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe connecting structure exerting excellent water pressure-resistant performance between a polyolefin resin pipe and a pipe joint having a release preventing function. SOLUTION: A seal rubber ring 4 is fitted in an annular recessed groove provided on the inner peripheral face on the opening end section side of a joint main body 2, and a slant groove expanded in diameter toward a depth section is provided on the inner peripheral face of the joint main body 2 located on the depth side from the rubber ring 4. The bayonet 51 of a resin pipe 5 fitted with a cylindrical reinforcing member 6 is inserted and connected into a socket idly arranged with a pipe fastening split ring having a slant outer peripheral face nearly matched with the inner peripheral face of the slant groove in the slant groove, and the outer diameter of the reinforcing member 6 is set to 97.5-99.8% of the inner diameter of the bayonet 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe connecting structure having a detachment preventing function.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 10-122461 discloses a pipe joint which can be easily connected simply by inserting a spigot of a pipe to be connected into a socket of the pipe joint and has a detachment preventing function. There are things that are. The detachment prevention pipe joint includes a cylindrical joint main body, a substantially C-ring-shaped detachment prevention ring, and a reinforcing member.

[0003]

However, the reinforcing member used in the above-mentioned conventional pipe joint is a member for reinforcing the spigot main body, but has a shape which can obtain a suitable effect for exhibiting the water pressure resistant strength. Was sometimes inadequate.

Further, in the conventional pipe joint, since the outer diameter of the folded portion of the reinforcing member exceeds the outer diameter of the spigot, when inserting the spigot with the reinforcing member into the socket, the pipe is tightened. In some cases, the cutting edge of the locking projection of the split ring may be damaged, and a sufficient detachment prevention effect may not be obtained.

However, in the case of stainless steel, the serrated blade formed on the inner peripheral surface is too hard,
For example, when the pipe to be inserted and connected is a polyolefin resin pipe such as a polyethylene resin pipe, the pipe is severely damaged, for example, by shaving the outer peripheral surface of the resin pipe, and its detachment preventing effect is low. Further, in the case of a separation prevention ring made of stainless steel, the rigidity thereof is too high, so that it is difficult to mount the separation prevention ring in the socket of the pipe joint.

An object of the present invention is to provide a pipe connection structure which exhibits excellent water pressure resistance, particularly as a pipe connection structure between a polyolefin resin pipe and a separation-preventing pipe joint.

[0007]

According to the first aspect of the present invention,
A rubber ring for sealing is mounted in an annular groove provided on the inner peripheral surface on the open end side of the joint body, and the inner peripheral surface of the joint body located on the back side of the rubber ring faces toward the back. It has an inclined groove for expanding the diameter, and in this inclined groove, a receiving ring in which a split ring for pipe tightening having an inclined outer peripheral surface substantially matched with the inner peripheral surface is arranged in a loosely fitted state, and in a spigot. In a pipe connection structure in which an inlet of a resin pipe to which a cylindrical reinforcing member is attached is inserted and connected, an outer diameter of the reinforcing member is 97.5 to 99.8% of an inner diameter of a spigot of the resin pipe. Is what it is.

According to a second aspect of the present invention, in the pipe connection structure of the first aspect, one end of the reinforcing member is folded outward to form a folded portion, and the maximum outer diameter of the folded portion is a resin pipe. 90 to 100% of the outer diameter of the port of No. 1.

In the present invention, the split ring for tightening the pipe is freely expandable and contractible in the radial direction. The material may be made of metal or resin, but from the viewpoint of water resistance, polyacetal or polyamide is preferred. , Polysulfone, polyphenylene sulfide, polyether ether ketone and the like are preferred. In the free state, the inner diameter of the split ring is slightly smaller than the outer diameter of the polyolefin resin pipe to be inserted and connected, and a plurality of locking ridges (for example, sawtooth-shaped Is desirable.

In the present invention, the outer diameter of the cylindrical reinforcing member mounted in the spigot of the resin pipe is 97.5 to 99.8%, particularly preferably 98.0%, of the inner diameter of the spigot of the resin pipe. ~ 9
9.5%. This is because if the outer diameter of the reinforcing member is less than 97.5% of the inner diameter of the spigot of the resin tube, sufficient water pressure resistance of the connection portion cannot be obtained. In other words, this is because the reinforcement as the reinforcing member is insufficient, and when the internal water pressure is applied, there arises a problem that the spout comes off from the receiving port.
Conversely, the outer diameter of the reinforcing member is 9 times the inner diameter of the spout of the resin tube.
If it exceeds 9.8%, it will be difficult to mount it on the outlet.

The maximum outer diameter of the folded portion of the reinforcing member is desirably 90 to 100%, particularly preferably 95 to 100%, of the outer diameter of the spout of the resin tube. This is because when the maximum outer diameter of the folded part exceeds the outer diameter of the spigot of the resin pipe, when inserting the spigot with the reinforcing member into the socket, the locking ridge of the split ring for pipe tightening is used. This is because the edge of the blade is damaged, and a sufficient detachment prevention effect cannot be obtained. In addition, it is necessary to increase the inner peripheral surface of the receiving port by the size of the folded portion, and in that case, the strength of the joint is insufficient.

Conversely, if the maximum outer diameter of the folded portion is less than 90% of the outer diameter of the spigot of the resin pipe, a large step will be generated between the spigot and the folded portion of the reinforcing member, and the reinforcing member will not be connected. This is because when the inserted spigot is inserted into the receptacle, the cutting edge of the pipe-tightening split ring is damaged, and a sufficient detachment prevention effect cannot be obtained.

Also, if the tip of the folded portion is sharp,
Since the cutting edge of the split ring for pipe tightening is damaged, it is desirable to chamfer the tip of the folded portion of the reinforcing member or to provide a parallel portion of about several mm.

In order to prevent the reinforcing member from coming off from the inside of the spigot of the resin pipe, it is desirable to provide a number of projections as slip preventing means on the outer surface of the reinforcing member. The height of this projection depends on the inner diameter of the spigot and the outer diameter of the reinforcing member,
0.3 to 1.5 mm is preferred. This is because when the height of the projection is less than 0.3 mm, the anti-slip effect is small, and
Conversely, if the height of the protrusion exceeds 1.5 mm, the inner surface of the spout will be significantly damaged, or it will be difficult to mount the reinforcing member in the spout of the resin pipe, and the inner diameter of the spout This is because the difference in the outer diameter of the cylindrical portion of the reinforcing member becomes large, and sufficient water pressure resistance at the connection portion cannot be obtained.

The material of the reinforcing member may be made of metal such as cast iron or aluminum, or may be made of FRP reinforced with reinforcing fibers such as glass fiber or carbon fiber.
In consideration of water resistance, stainless steel is preferable. The folded portion has one end portion of the cylindrical portion folded outwardly in an umbrella shape and has an inclined surface, and has an inclination angle of 10 to 50 degrees so that the spigot can be smoothly inserted into the socket. desirable. Further, it is preferable that the turning surface is not turned at an acute angle but is added with R. It is desirable that the length of the reinforcing member is substantially the same as the insertion margin of the socket of the joint body. This is because if the length is too short, there is no effect of suppressing the cold flow of the resin pipe due to the tightening force from the rubber ring.
No further effect can be expected and it is uneconomical.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the pipe connection structure of the present invention will be described below with reference to the drawings. FIG. 1 is a semi-longitudinal sectional view showing a first embodiment of the pipe connection structure of the present invention, FIG. 2 is a semi-longitudinal sectional view showing a part of a pipe joint for preventing separation in FIG. 1, and FIG. 3 is a reinforcing member in FIG. FIG.

In FIG. 1, the resin tubes 5 and 7 are both formed by extrusion molding from a high-density polyethylene resin having a density of 0.940 or more. One end surface of the resin pipe 7 is butt-fused with the end surface on the small diameter side of the pipe joint 1 having a socket, and the two are integrated. The spigot 51 of the resin pipe 5 in which the short cylindrical reinforcing member 6 is inserted on the inner peripheral surface side of the spigot 51
Is inserted and connected into the socket of the pipe joint 1 so that the resin pipe 5
And a connection structure between the resin tube 7 and the resin tube 7.

The pipe joint 1 is of a type having a detachment preventing function, and includes a joint body 2 and a split ring 3 for pipe tightening.
And a sealing rubber ring 4. The joint body 2 is a cylindrical member made of polyethylene resin, and has a large-diameter end having a socket provided with an insertion opening for the resin pipe 5 to be connected, and an inner peripheral surface on the insertion opening side. An annular groove 21 is provided in the annular groove 21, and a sealing rubber ring 4 is mounted in the annular groove 21. The joint body 2 located on the back side of the rubber ring 4
Of the inner peripheral surface 22 is tapered toward the back to form an inclined groove 23.

In the inclined groove 23, a split ring 3 for pipe tightening is arranged in a loosely fitted state. The split ring 3 has a part of the pipe wall cut out, and has a slanted outer peripheral surface 31 substantially matching the inner circumferential surface 22 of the slanted groove 23. In the free state, the split ring 3 has an inner diameter slightly smaller than an outer diameter of a spigot 51 of the resin tube 5 described later, and a large number of saw-tooth-shaped locking projections 32 are provided on an inner peripheral surface thereof. Is provided. The split ring 3 is formed from a linear polyphenylene sulfide resin by an injection molding method. In this case, the linear polyphenylene sulfide resin has a flexural modulus of 3630 MPa and a notched Izod impact value of 25 J / m. Those having properties were used ["Polytron" (registered trademark) of Polyplastics Co., Ltd .: Grade 0220U9].

The reinforcing member 6 is made of corrosion-resistant stainless steel and has a short cylindrical portion 61 and a folded portion 62 as shown in FIG. 2, and the outer diameter of the short cylindrical portion 61 is a resin pipe. 5 is 97.5 to 99.8% of the inner diameter of the port 51. As shown in FIG. 3, small protrusions 63 serving as non-slip means are cut and raised on the outer peripheral surface of the short cylindrical portion 61 and provided at four positions in the circumferential direction. Folding part 62
Is formed such that one end of the short cylindrical portion 61 is outwardly folded in an umbrella shape to form a tapered surface.

Then, as shown in FIG.
Is formed so as to surround the outer peripheral edge of the end face of the spout 51 of the resin pipe 5. The maximum outer diameter of the folded portion 62 is 90 to 100% of the outer diameter of the spout 51 of the resin pipe 5. It has been.

When the spigot 51 of the resin pipe 5 is inserted from the insertion opening of the pipe joint 1 toward the back, the split ring 3 is pushed out by the tapered surface 64 of the outer peripheral surface of the folded portion 62 of the reinforcing member 6. Therefore, it can be inserted to the back side. In addition, a contact step 24 with which the outer peripheral surface of the folded back portion 62 of the reinforcing member 6 comes into contact is formed on the inner peripheral surface at the back of the socket of the joint body 2.

In this case, since the split ring 3 is made of a linear polyphenylene sulfide resin, it does not cause plastic deformation or cracking due to the expansion, and its elastic restoring force makes it slightly smaller than the outer diameter of the resin pipe 5. The diameter is reduced to the original free state of the inner diameter.

Further, when the end of the folded portion 62 is inserted deeper than the split ring 3, the pipe joint 1
Alternatively, when a force in the detaching direction of the resin pipe 5 is applied to the pipe joint 1, the split ring 3 is also moved toward the insertion port with the movement of the resin pipe 5 by the action of the serrated locking ridge 32 of the split ring 3. The outer peripheral surface 31 is moved and the tapered surface 2 of the inclined groove 23 is moved.
2 and the split ring 3 contracts in diameter. Therefore, the outer peripheral surface of the spigot 51 of the resin tube 5 is firmly gripped by the inner peripheral surface of the split ring 3, and the resin tube 5 is reliably prevented from coming off.

Further, the spigot 51 is reinforced from the inside by press-fitting the short cylindrical portion 61 of the reinforcing member 6 into the spigot 51 of the resin pipe 5, so that the split ring 3 and the seal Even if the tightening force is continuously applied to the resin pipe 5 by the rubber ring 4 for a long time, the spigot 51 of the resin pipe 5 does not undergo dimensional deformation due to cold flow. In addition, since the small protrusions 63 serving as non-slip means are provided on the outer peripheral surface of the short cylindrical portion 61 of the reinforcing member 6 at four places in the circumferential direction, the resin pipe is left in the joint body 2 with the reinforcing member 6 left. The trouble that the spigot 51 of the No. 5 slips through can be surely prevented.

[0026]

Examples 1 to 3 The resin pipes 5 and 7 made of high-density polyethylene resin having a nominal diameter of 75 mm were used, and the connection portions were subjected to water pressure resistance. Specifically, the open ends of both resin tubes 5 and 7 are closed with plugs, and both closed resin tubes 5 and 7 are placed and supported on a predetermined receiving stand. The plug on the resin tube 7 side is connected to a pressure pump so that a predetermined internal water pressure can be applied to the test object. Then, the outer diameter (d3) of the reinforcing member 6 and the inner diameter (d1) of the port 51 of the resin pipe 5
And the dimensional ratio (d4 / d2) between the outer diameter (d4) of the folded portion of the reinforcing member 6 and the outer diameter (d2) of the spout 51 of the resin pipe 5 is changed. Regarding the connection structure, an internal water pressure of up to 2.5 MPa is applied by a pressurizing pump and maintained for 2 minutes.
The internal water pressure was applied until about a, and the presence or absence of leakage and abnormalities from the connection part was confirmed. In addition, d3 / d1 ratio is 0.96.
7 to 0.972 for Comparative Examples 1 to 3, d4 / d2 ratio of 0.893, and 1.008 to 1.012 for Comparative Example 4.
-6 and evaluated similarly. Table 1 and Table 2 show the results.
Shown in In the column of water pressure resistance test, ○ indicates that even when the internal water pressure was applied up to the maximum burst pressure of the pipe of 5.0 MPa, there was no abnormality in the connection such as water leakage or disconnection of the pipe, and × indicates the connection. Indicates that there was an abnormality. As shown in Table 1, d3
/ D1 ratio is in the range of 0.975 to 0.998, and
When the d4 / d2 ratio is 0.900 to 1.000, it is clear that water can be sufficiently stopped. The nominal diameter is 10
The performance of the resin tubes 5 and 7 of 0 mm and 150 mm was evaluated in the same manner as described above, and as a result, the performance as shown in Table 1 could be obtained.

[0027]

[Table 1]

[0028]

[Table 2]

The present invention is not limited to the above embodiment. For example, in the above embodiment, the resin pipe 5 is connected to only one side of the joint main body 2, but a structure in which the resin pipe 5 can be connected to both sides of the joint main body 2 may be adopted.

[0030]

According to the pipe connection structure of the present invention, the outer diameter of the reinforcing member is 9 times the inner diameter of the inlet of the resin pipe.
By setting the ratio to 7.5 to 99.8%, the spigot of the resin pipe inserted and connected into the receptacle is suitably reinforced by the reinforcing member, and as a result, the spigot of the resin pipe from the receptacle is formed. The detachment can be prevented by the split ring for pipe tightening, and it has excellent water pressure resistance.

According to the second aspect of the present invention, the reinforcing member has a folded portion, and the maximum outer diameter of the folded portion is 90 to 100% of the outer diameter of the spigot. When inserting the spout, the tip of the folded part of the reinforcing member does not damage the cutting edge of the locking ridge of the split ring for pipe tightening, and maintains a sufficient separation prevention effect and water pressure resistance performance for a long time Can be.

[Brief description of the drawings]

FIG. 1 is a half longitudinal sectional view showing a first embodiment of a pipe connection structure of the present invention.

FIG. 2 is a semi-longitudinal sectional view showing the pipe joint before connection in FIG.

FIG. 3 is a semi-longitudinal sectional view showing a reinforcing member in FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pipe joint 2 joint main body 21 annular concave groove 22 inner peripheral surface 23 inclined groove 3 split ring for pipe tightening 31 inclined outer peripheral surface 32 serrated locking ridge 4 rubber ring for sealing 5, 7 resin pipe 51 spout 6 Reinforcement member 61 Short cylindrical part 62 Folded part 63 Small protrusion

Claims (2)

[Claims] A rubber ring for sealing is mounted in an annular groove provided on an inner peripheral surface on an opening end side of a joint body, and an inner peripheral surface of the joint body located deeper than the rubber ring is provided. A receiving groove in which a split ring for tightening a pipe having an inclined groove having an inclined outer surface whose inner diameter is substantially matched with an inclined groove having an inclined groove whose diameter is increased toward a deep portion is disposed in the inclined groove; In a pipe connection structure in which a spigot of a resin pipe in which a cylindrical reinforcing member is mounted is inserted and connected in the spigot, an outer diameter of the reinforcing member is 97.5 to an inner diameter of the spigot of the resin pipe.
A pipe connection structure characterized by being 99.8%. 2. A method according to claim 1, wherein one end of the reinforcing member is bent outward to form a folded portion, and the maximum outer diameter of the folded portion is 90 to 100% of the outer diameter of the spout of the resin pipe. Item 1
The described pipe connection structure.