JP4860655B2 - Dissimilar pipe joint - Google Patents

Description

  The present invention relates to a dissimilar pipe joint for joining dissimilar pipe members such as a synthetic resin pipe member (polyethylene resin pipe or the like) and a metal pipe member (metal screw joint or the like) in a relatively rotatable manner.

Conventionally, as a pipe joint, a tubular joint body having a groove with a tapered side wall on the side of the insertion port of the pipe to be connected, a loose fitting in the groove, and a cutting part in a part of the circumferential direction A separation preventing ring formed of a synthetic resin having a diameter smaller than the outer diameter of the tube main body of the tube and having a Rockwell hardness of 78 or more on an M scale, When the pipe is connected so that the protrusion formed on the outer peripheral surface of the pipe body is located on the back side of the separation prevention ring, when the force in the pulling direction of the pipe is applied to the pipe and the pipe joint, the protrusion is detached. A structure is known in which the wall of the prevention ring opposite to the insertion port is locked to press the separation prevention ring against a tapered surface (see, for example, Patent Document 1).
JP-A-10-73189

  However, in the conventional pipe joint, since the joint body and the pipe body are sealed using a tapered surface, if a sealing function for increasing the sealing pressure and suppressing water leakage is secured, There has been a problem that the relative rotation function cannot be secured, and if the seal pressure is lowered and the relative rotation function between the joint body and the pipe body is secured, the seal function for suppressing water leakage cannot be secured.

  In addition, when a force in the direction of pulling out the pipe is applied to the pipe and the pipe joint, the sealing pressure increases. Conversely, when a force in the direction of pulling out the pipe is not applied to the pipe and the pipe joint, the sealing pressure is reduced. There was a problem that the seal pressure fluctuated greatly under the influence of external force.

  Furthermore, since the joint body and the pipe body are sealed using the taper surface, if a large pulling force acts on the pipe during an earthquake, etc., the pipe is easy to come off, and it is not possible to construct an earthquake resistant pipeline. There was a problem.

  Therefore, if the initial seal pressure is increased in advance, the tube joint has only a sealing function, and a rotation mechanism is added separately to achieve the relative rotation function, the structure becomes complicated and the number of parts increases and the cost increases. There was a problem of becoming.

  The present invention has been made by paying attention to the above-mentioned problems. The number of parts is small, the structure is simple and inexpensive, and the balance between the seal function and the relative rotation function by torque management and the suppression of seal pressure fluctuation due to the influence of the axial external force are suppressed. Another object of the present invention is to provide a dissimilar pipe joint that can achieve the construction of a seismic duct.

In order to achieve the above object, the dissimilar pipe joint of the present invention is
A synthetic resin adapter having a cylindrical shape, having a first pipe connecting portion for connecting a synthetic resin pipe member on one side, and a flange on the opposite side;
It has the 2nd pipe connection part which connects a metal pipe member to one side, and is larger than the 1st contact surface which is in surface contact with the collar outer end surface of the synthetic resin adapter on the other side, and the collar outer diameter of the synthetic resin adapter A metal joint body member having a parallel thread portion by an inner diameter;
A cap nut having a second contact surface that is screw-fitted to the parallel screw portion and is in surface contact with the inner end surface of the flange portion of the synthetic resin adapter,
A seal ring mounted on a seal ring groove formed on one surface of the first outer peripheral surface of the flange portion of the synthetic resin adapter and the first contact surface of the metal joint body member;
The cap nut is screw-fitted to the parallel thread portion of the metal joint body member with a tightening torque within a predetermined torque range, and seals the maximum internal water pressure assumed as the predetermined torque range. Is the minimum torque value of the cap nut tightening torque, and the upper limit torque that allows relative rotation with respect to the synthetic resin adapter when human force is applied to the metal pipe member connected to the metal joint body member from the outside. Set to the range of maximum torque value of cap nut tightening torque ,
The cap nut is tightened with a torque within a predetermined torque range with respect to the parallel thread portion of the metal joint body member, and then the radial hole communicating with the through hole formed in the metal joint body member is formed in the bag. A means for forming a nut and incorporating a rotation-preventing member into the through hole and the radial hole is provided .

Therefore, in the dissimilar pipe joint according to the present invention, the first outer contact surface of the synthetic resin adapter and the second inner end surface of the synthetic resin adapter are clamped by the first contact surface of the metal joint body member and the second contact surface of the cap nut, and The seal ring is interposed between the outer end surface of the flange portion of the synthetic resin adapter and the first contact surface of the metal joint body member.
Then, when screwing the cap nut, the torque management is performed so that the tightening torque is within a predetermined torque range, and the tightening torque necessary to seal the assumed maximum internal water pressure is set as the predetermined torque range. The tightening torque at which the synthetic resin adapter and the metal joint body member can rotate relative to each other when the human pipe member connected to the metal joint body member is externally applied is set as the maximum torque value. For this reason, it is possible to achieve both a sealing function for preventing fluid leakage at the assumed maximum internal water pressure and a relative rotating function for adjusting the relative rotational positional relationship between the synthetic resin adapter and the metal joint body member by human power.
Further, even if an external force is applied in the tube axis direction, the movement is restricted by surface contact in both the withdrawal direction and the insertion direction, so that variation in seal pressure due to the influence of the axial direction external force can be suppressed.
Furthermore, since it is not a taper surface fitting structure but a vertical surface fitting structure to the flange of the synthetic resin adapter, even if a large pulling force acts on the pipe during an earthquake, the pipe will not come out, so the earthquake resistant pipe Can be built.
As a result, only a synthetic resin adapter, a metal joint body member, a cap nut, and a seal ring are provided. Compared with the case where a rotation mechanism is added, the number of parts is small and the structure is simple and inexpensive. It is possible to achieve both the rotation function, the suppression of fluctuations in the seal pressure due to the influence of the external force in the axial direction, and the construction of the earthquake-resistant conduit.
Further, after tightening the cap nut with a torque within a predetermined torque range with respect to the parallel thread portion of the metal joint body member, the through hole formed in the metal joint body member serves as a guide, and the radial direction communicates with the through hole. A hole is formed in the cap nut. And a detent | locking member is integrated in the through-hole and radial direction hole which mutually communicate in radial direction.
Therefore, even if vibration or the like is applied to the dissimilar pipe joint joint in the construction state, the screw fitting portion between the metal joint body member and the cap nut is not loosened, and the tightening torque within the predetermined range of the cap nut is maintained. be able to.

  Hereinafter, the best mode for realizing a dissimilar pipe joint according to the present invention will be described based on Example 1 shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall view showing an example of a seismic resistant pipeline in which the dissimilar pipe joint J of Example 1 is applied as a polyethylene resin pipe joint to a gate valve.

  As shown in FIG. 1, the seismic conduit to which the heterogeneous pipe joint J of Example 1 is applied includes a gate valve box 1, a gate valve 2 (metal pipe member), an EF socket 3, and a polyethylene resin pipe 4 ( Synthetic resin pipe member).

  As shown in FIG. 1, one end side of the dissimilar pipe joints J is connected to a pair of metal screw joints 22 and 22 provided at the lower part of the gate valve 2 having a handle 21 at the upper part by screwing. Is done. As shown in FIG. 1, polyethylene resin pipes 4 and 4 having EF (electrical fusion) sockets 3 and 3 are connected to the other end sides of the dissimilar pipe joints J and J, respectively, by fusion bonding.

  FIG. 2 is an overall cross-sectional view showing the dissimilar pipe joint J of Example 1. 3 is a cross-sectional view showing a polyethylene adapter in the dissimilar pipe joint J of Example 1. FIG. 4A and 4B show a metal joint body member in the dissimilar pipe joint J of Example 1, where FIG. 4A is a cross-sectional view and FIG. 4B is a right side view. 5 shows a cap nut in the dissimilar pipe joint J of Example 1, wherein (a) shows a left side view and (b) shows a cross-sectional view. FIG. 6 is a cross-sectional view of a main part showing a screwed state of a rotation preventing pin in the dissimilar pipe joint J according to the first embodiment. The structure of the dissimilar pipe joint J of Example 1 is demonstrated based on FIGS.

  As shown in FIG. 2, the dissimilar pipe joint J of Example 1 includes a polyethylene adapter 5 (synthetic resin adapter), a metal joint body member 6, a cap nut 7, an O-ring 8 (seal ring), A stop pin 9 (non-rotating member) and a bottomed pin hole 10 (radial direction hole) are provided.

  As shown in FIG. 3, the polyethylene adapter 5 has a cylindrical short tube structure, and has a cylindrical outer peripheral surface 51 (first tube connecting portion) for connecting a polyethylene resin tube 4 (synthetic resin tube member) on one side. And it has the collar part 52 on the opposite side. The cylindrical outer peripheral surface 51 is set to a length that can be fused twice (for example, around 150 mm). The flange 52 includes a flange outer end surface 53 that is in surface contact with the first contact surface 62 of the metal joint body member 6, and a flange inner end surface 54 that is in surface contact with the second contact surface 72 of the cap nut 7. The polyethylene adapter 5 can be manufactured by injection molding or by cutting a polyethylene resin tube.

  As shown in FIG. 4A, the metal joint body member 6 has a male screw port 61 (second pipe connection) that is screwed into a metal screw joint 22 (metal pipe member) of the gate valve 2 on one side. A first contact surface 62 that is in surface contact with the flange outer end surface 53 of the polyethylene adapter 5 and a parallel screw portion 63 having an inner diameter larger than the outer diameter of the flange 52 of the polyethylene adapter 5 on the opposite side. Have. As shown in FIG. 4A, an O-ring groove 64 (seal ring groove) for mounting the O-ring 8 in an embedded state is formed in the first contact surface 62 in an annular shape. On the outer peripheral surface of the parallel screw portion 63, as shown in FIG. 4 (b), a polygonal surface 65 (12-sided surface) is sandwiched and rotated at a diagonal position by a pipe wrench. Further, the polygonal surface 65 is formed with a through hole 66 having a female thread on the inner surface. The metal joint body 6 is a gun metal, and can be manufactured by cutting a continuous cast bar or by casting. In place of the male screw opening 61, a female screw opening may be used.

  As shown in FIG. 5 (b), the cap nut 7 has a male screw portion 71 that is screw-fitted with the parallel screw portion 63, and a second contact surface 72 that is in surface contact with the inner end surface 54 of the flange portion of the polyethylene adapter 5 at the end surface. Have As shown in FIG. 5A, the outer peripheral surface on the opposite side of the male screw portion 71 has a polygonal surface 73 (octagonal surface) for sandwiching and rotating at a diagonal position by a pipe wrench. Further, the nut inner diameter D ′ of the cap nut 7 is slightly larger than the adapter outer diameter D ″ by an interval that includes the variation and the minimum gap when the adapter outer diameter of the polyethylene adapter 5 is D ″. (For example, nut inner diameter D ′ = 64.2 mm, pipe outer diameter D ″ = 63.2 mm), a minimum clearance C (see FIG. 6) is set at the time of assembling. L (for example, L = 29 mm) is set to a length that is about half of the adapter inner diameter of the polyethylene adapter 5. The cap nut 7 is a gun metal like the metal joint body 6 and cuts a continuous cast bar. It can be manufactured by processing or by casting.

  As shown in FIG. 6, the O-ring 8 is mounted in an O-ring groove 64 formed in the first contact surface 62 of the metal joint body member 6. After this O-ring 8 is mounted in the O-ring groove 64, a silicone-based lubricant is applied, and then the cap nut 7 is tightened to integrate the polyethylene adapter 5 and the metal joint body member 6. . EPDM (abbreviation for “ethylene propylene diene rubber”) with excellent aging resistance, weather resistance, ozone resistance, and oil resistance (alcohol, ketone (MEK), ethyl acetate), etc. is used as the material of this O-ring 8 It is done.

As shown in FIG. 6, the locking pin 9 includes a screwed head 91 that is screwed in a through hole 66 in which the female thread of the metal joint body member 6 is cut, and a bottomed pin hole 10 of the cap nut 7. And a pin portion 92 to be inserted. The bottomed pin hole 10 into which the detent pin 9 is incorporated is not formed in the cap nut 7 in advance, but at a torque within a predetermined torque range with respect to the parallel threaded portion 63 of the metal joint body member 6. After tightening the cap nut 7, the through hole 66 formed in the metal joint body 6 is used as a guide, and the bottomed pin hole 10 in the radial direction reaching the middle position of the cap nut 7 is formed by a drilling machine or the like. And the detent | locking pin 9 is integrated in the through-hole 66 and the bottomed pin hole 10 which mutually communicate with radial direction. This locking pin 9 assumes the pin diameter d of the pin portion 92 and the pin portion when the site operator assumes a tightening operation in which the polygonal surface 73 of the cap nut 7 is rotated with a pipe wrench and the tightening operation is performed. The torque acting on 92 is assumed to be a virtual torque (= assumed construction torque T), and is set to a diameter that does not break even if a tightening operation is performed based on this virtual torque.
The calculation formula of the pin diameter d is, for example,
Pin diameter d = (Assumed construction torque T / Pin radius R / Pin material allowable stress × 4 / π) ^0.5
= (1500 (kgf · cm) / 4 (cm) / 2000 (kgf / cm ² ) × 4 / π) ^0.5
= 0.49cm
It becomes. Therefore, even if there is a torque input exceeding the assumed construction torque T, the safety factor is estimated with respect to the calculated value so that the fracture can be prevented, for example, the pin diameter d = φ6 mm.

Further, the cap nut 7 is screw-fitted with a tightening torque within a predetermined torque range in which the polyethylene adapter 5 and the metal joint main body member 6 are relatively rotatable without leaking with respect to the internal water pressure. .
The torque range defined in advance will be described in more detail. The lower limit torque necessary for sealing the assumed maximum internal water pressure is set as the minimum torque value of the cap nut tightening torque T, and the handle 21 of the gate valve 2 is manually operated from the outside. The upper limit torque that can perform relative rotation is set in a range that is the maximum torque value of the cap nut tightening torque T.
When this is replaced with a specific value, when the cap nut tightening torque is T (kgf · cm) and the outer diameter of the polyethylene resin pipe is D (cm),
0.5D ³ ≦ T ≦ 1000
It is the range represented by the formula of Further, within this range, 1.5D ³ −100 ≦ T ≦ 1.5D ³ +100 is set as the optimum torque range.

Next, the operation will be described.
First, the “development process of dissimilar pipe joints” will be described, and then the effects of the dissimilar pipe joints J of Example 1 will be referred to as “torque range setting action of cap nut tightening torque”, “joint assembly action”, The explanation will be divided into “Construction of seismic ducts using joints”.

[Background of development of dissimilar pipe joints]
FIG. 7 is a cross-sectional view showing an example of a conventional dissimilar pipe joint. FIG. 8 is a view showing a state in which a short pipe portion is joined with an EF socket when a seismic duct is constructed using a conventional dissimilar pipe joint. FIG. 9 is a view showing a state in which the handle of the gate valve is tilted to the inner surface of the gate valve box due to twisting of the pipe due to backfilling. FIG. 10 is a cross-sectional view showing an example of a joint with a rotation mechanism in which a rotation mechanism is added to a conventional dissimilar pipe joint.

A male adapter as shown in FIG. 7 is known as a joint for joining a polyethylene resin pipe and a metal joint such as a gate valve and a threaded joint.
In this joint, the cap nut is passed through the pipe, the pipe is inserted into the joint body, and the cap nut is tightened to expand the diameter of the pipe with the insert core. It is a joint that has a structure that prevents the outer diameter of the pipe expanded by the lock ring from falling out.

  With this joint, a hard seal is secured when the cap nut has a small tightening force, but the tube pull-out prevention force is insufficient, and even if there is no water leakage in a water pressure test, etc., the tensile force of the tube during an earthquake, etc. May cause the tube to come off.

  Therefore, in order to reduce the quality variation, it is possible to manage the tightening force of the short pipe and the joint in advance and join them at the factory. In this case, in the case of a polyethylene resin pipe, on-site construction is to construct an earthquake resistant pipe line by joining the polyethylene resin short pipe portion with an EF socket or the like as shown in FIG.

  However, after piping as shown in Fig. 8, if the metal joint or gate valve is not tightened (screw joint) sufficiently and water leaks from the screw part in the water pressure test, the screw joint part should be If it is forcibly tightened, water may leak from the polyethylene resin short tube part and the joint tightening part tightened at the factory.

  When the screw type gate valve is fastened to the joint so that the handle is turned up and then backfilled, as shown in FIG. 9, the pipe is twisted and the handle of the gate valve is tilted so that the handle is It may contact the inner surface of the gate valve box and hinder the valve operation. Even at this time, if the handle of the gate valve is set straight up, there is a possibility that water leaks from the polyethylene resin short pipe part tightened at the factory and the joint tightening part.

Therefore, as shown in FIG. 10, a joint is conceivable in which a metal part of the joint is provided with a rotation mechanism and a short pipe is incorporated at a factory.
This joint has a structure in which the joint body and the rotating socket are separated, and the cover is embedded by embedding the rotating ring therein, but the structure is complicated, the number of parts is high, and the strength of the rotating ring is high. There is a weak point that is insufficient and weak against the axial pull-out force.
Further, the cap nut and the joint body are tightened with parallel screws, and this screw portion may be loosened due to vibration caused by a vehicle load at the time of embedment and the tube may come off.

  As described above, any of the conventional dissimilar pipe joints has a problem to be solved. Considering these issues as a whole, the structure of the joint is simple and inexpensive, and the joint is strong against the axial pull-out force, while the polyethylene resin tube part and the metal screw part can rotate while ensuring the sealing performance. Development is sought after. The present inventor attempted to review the joint structure in the environment surrounding such joints, and aimed to achieve all the required performance while simplifying the structure to the maximum while aiming for development. A heterogeneous pipe joint was proposed.

[Torque range setting action of cap nut tightening torque]
FIG. 11 is a torque relationship characteristic diagram showing the relationship between the cap nut tightening torque and the metal joint main body rotation torque for explaining the range of the necessary cap nut tightening torque.

In Example 1, when the outer diameter of the polyethylene resin pipe is D (cm) as described above as a pre-defined torque range of the cap nut tightening torque T (kgf · cm), 0.5D ³ ≦ T ≦ 1000 The range represented by the equation was set, and within this range, T = 1.5D ³ ± α was set as the optimum torque range. The reason why this equation is obtained and the critical significance will be explained.

In order to seal, the surface pressure (Ps) between the polyethylene adapter 5 and the metal joint body member 6 is preferably higher than the internal water pressure of the internal fluid.
The tightening torque (T) and the tightening force (F) of the cap nut 7 are generally obtained from the following equations.
F = T / (EC) ... Formula (1)
Where T: Tightening torque (kgf · cm)
E: Cap nut screw diameter (8.1534cm (G2 3/4))
C: Friction coefficient of screw (0.2)
Further, the surface pressure (Ps) is obtained from the following equation.
Ps = F / A (2)
Where A: area of the contact surface of the polyethylene adapter and the metal joint body (cm ² )
If the outer diameter of the flange 52 of the polyethylene adapter 5 is 78 mm, the inner diameter is 51.8 mm, the outer diameter of the O-ring groove 64 of the metal joint body member 6 is 72 mm, and the inner diameter is 57 mm, the polyethylene adapter and the metal joint body contact surface The area A of
A = (π / 4) × (78 ² -51.8 ^2- (72 ² -57 ² )) = 11.51 cm ²
It becomes.

Therefore, the surface pressure (Ps) is expressed by the formulas (1) and (2) as follows:
Ps = T / 18.77kgf / cm ² (3)
Thus, if the surface pressure (Ps) is known, the tightening torque T can be calculated by the equation (3).
Here, assuming that the internal water pressure (= required surface pressure) is 10 kgf / cm ² , the initial required tightening torque is 185 kgf · cm according to Equation (3).

  On the other hand, after tightening the cap nut 7 and applying the non-rotating pin 9, the polyethylene adapter 5 is fixed, and the relationship of the initial torque at which the metal joint body member 6 rotates is measured for each cap nut tightening torque. 11 shows.

The height H to the handle 21 of the gate valve 2 having a nominal diameter of 50 mm is about 23 cm (see FIG. 1). Considering that the human force that can rotate the handle 21 with the gate valve box 1 in the vicinity is 30 kgf at most, the screw of the gate valve 2 is located at two places on the left and right.
23cm × 30kgf / 2 = 345kgf · cm
That is, it must be 345 kgf · cm or less. In other words, if it exceeds 345 kgf · cm, it is difficult to manually rotate the handle 21.

  These relationships are shown together in FIG. 11, and the torque tightened at the factory needs to be in the range of 185 kgf · cm to 1000 kgf · cm.

The smaller the rotational force of the handle 21 of the gate valve 2, the better. Also, from experiments, the stress relaxation characteristics of the polyethylene adapter 5 may be 1/3 of the initial surface pressure in the long term assuming 50 years of use. Therefore, the optimum tightening torque is
185 × 3 = 555kgf · cm
become.

The generalization of these relationships is that, when the outer diameter of the polyethylene resin pipe is D (cm), in the polyethylene resin pipe for water distribution, from SDR11,
Pipe inner diameter = DD / 11 x 2
It becomes.鍔 Outer diameter is almost twice the tube thickness,
鍔 Outer diameter = D + D / 11 × 2
It becomes. The area A of the O-ring groove 64 is about half of the contact surface,
A = π / 4 (Tsubagai径² - tube inner diameter ²⁾ × 1/2
It becomes. The relationship between torque T and axial force F is F = T / 鍔 outer diameter, and the initial surface pressure is 10 kgf / cm ² .
The initial tightening torque T required for the seal is
T ≧ 0.5D ³ kgf · cm
It becomes.
On the other hand, as is apparent from FIG. 11, the initial tightening torque T that allows the handle 21 of the gate valve 2 to rotate is 1000 kgf · cm. Therefore,
0.5D ³ ≦ T ≦ 1000
After tightening the cap nut 7 with a tightening torque T (kgf · cm) within the range, the detent pin 9 is hit. The critical significance of this torque lower limit value and torque upper limit value means that when the initial tightening torque T is less than 0.5D ³ kgf · cm, water leakage is likely to occur when the internal water pressure in the maximum pressure range is applied. If the initial tightening torque T exceeds 1000 kgf · cm, it means that it is difficult to manually rotate the handle 21 of the gate valve 2 after fixing the pipe.

In consideration of the fact that the tightening torque becomes about 1/3 after long-term use, about three times the initial tightening torque T required for sealing is the tightening torque that can ensure the sealing performance even after long-term use. Therefore, the optimal value is
0.5D ³ × ³ = 1.5D ³
It becomes. As shown in FIG. 11, ± α (for example, α = 100 kgf · cm), which is an allowable amount around 1.5D ³ , is set to an optimum torque range (1.5D ³ −100 ≦ T ≦ 1.5D ³ +100).
In the first embodiment, the example of the metal joint main body member 6 having the male screw is shown, but the same can be said for the metal joint main body member having the female screw.

[Fitting assembly action]
FIG. 12 is a cross-sectional view of a principal part showing a state in which the dissimilar pipe joint J of Example 1 is assembled at the factory.

The joint assembling action for assembling the dissimilar pipe joint F of Example 1 at the factory will be described.
First, the O-ring 8 is mounted in the O-ring groove 64 formed in the first contact surface 62 of the metal joint body member 6, and after mounting the O-ring 8, a silicone-based lubricant is applied, and then the flange 52 The polyethylene adapter 5 is inserted into the metal joint body member 6 so that the outer end surface 53 of the heel is pressed against the O-ring 8. Then, the male screw portion 71 of the cap nut 7 is screwed into the parallel screw portion 63 of the metal joint main body member 6, and the polyethylene nut 5 and the metal joint main body member 6 are tightened by turning the cap nut 7 with a pipe wrench. Is integrated. Here, the tightening torque of the cap nut 7 does not leak with respect to the internal water pressure as described above, and is within a predetermined torque range in which the polyethylene adapter 5 and the metal joint main body member 6 are relatively rotatable. Controlled by tightening torque.

  Thus, after tightening the cap nut 7 with a torque within a predetermined torque range with respect to the parallel threaded portion 63 of the metal joint body member 6, the inner diameter of the through hole 66 formed in the metal joint body 6 is increased. As a guide, a bottomed pin hole 10 (φ6 mm) in the radial direction reaching the middle position of the cap nut 7 is formed by a drilling machine or the like. Then, the non-rotating pin 9 is screwed into the through hole 66 and the bottomed pin hole 10 communicating with each other in the radial direction so as to be embedded.

  As shown in FIG. 12, the dissimilar pipe joint J of Example 1 assembled in the factory through the above steps is in contact with the first contact surface 62 of the metal joint body member 6 and the second contact of the cap nut 7. The surface 72 clamps the flange outer end surface 53 and the flange inner end surface 54 of the polyethylene adapter 5, and elastically deforms between the flange outer end surface 53 of the polyethylene adapter 5 and the first contact surface 62 of the metal joint body member 6. The O-ring 8 is interposed.

And in the dissimilar pipe joint J of Example 1, as mentioned above, when screwing the cap nut 7, it does not leak with respect to internal water pressure, but the polyethylene adapter 5 and the metal joint main body member 6 are relative to each other. Torque management is performed at the time of assembly at the factory, so that the tightening torque is within a predetermined torque range that can rotate. For this reason, it is possible to achieve both a sealing function that prevents leakage of fluid flowing through the pipe system and a relative rotation function that allows relative rotation of the polyethylene adapter 5 and the metal joint body member 6.
Regarding the “seal function”, according to a water pressure test using a prototype, it was confirmed that the test standard of “no abnormality such as leakage in 3 minutes at 2.5 MPa” was cleared. According to the pulsating water pressure test on the prototype, it was confirmed that the test standard of “no abnormality when repeating pulsating water pressure of 0MPa-3.0MPa 100,000 times” was cleared. According to the hot internal pressure creep test on the prototype, it was confirmed that the test standard of “no abnormality for 165 hours when water pressure of 1.1 MPa was applied at 80 ° C water” was cleared.
As for the “relative rotation function”, according to a scrape property test on a prototype, it was confirmed that the test standard “can be scraped by holding the metal part by hand” is cleared without rotating together.

  Further, since the first contact surface 62 and the second contact surface 72 sandwich the flange outer end surface 53 and the flange inner end surface 54 of the polyethylene adapter 5, even if an external force is applied in the tube axis direction, the pulling direction is reduced. In addition, since movement in the insertion direction is restricted by surface contact, there is no fluctuation in the sealing pressure due to the influence of the axial external force as in the case of the tapered face seal, and the fluctuation in the sealing pressure due to the influence of the axial external force can be suppressed. Therefore, when the dissimilar pipe joint J of Example 1 is in the construction state, both the “seal function” and the “relative rotation function” can be maintained even if an external force is applied in the pipe axis direction due to various factors. .

[Construction of seismic ducts using joints]
FIG. 13 is an explanatory view of the returning action of returning the gate valve tilted by twisting of the pipe by backfilling to the original vertical state only by applying human power to the handle. FIG. 14 is an explanatory view showing a bending water pressure resistance test of a pipe using the dissimilar pipe joint J of Example 1.

  When constructing a seismic resistant pipe using the dissimilar pipe joint J of Example 1, a pair of metal screw joints 22 and 22 of the gate valve 2 are connected to the dissimilar pipe joints J and J using a pipe wrench. Screw the male screw openings 61 and 61 of the metal joint body member 6 on one end side. As shown in FIG. 1, the EF sockets 3 and 3 are fused to the polyethylene adapters 5 and 5 of the dissimilar pipe joints J and J, and the polyethylene resin tubes 4 and 4 are fused to the EF sockets 3 and 3. To wear. Then, the earth dug for the piping is backfilled to construct the earthquake resistant pipeline. The EF socket 3 may be fused to the polyethylene adapter 5 at a factory in advance.

  When the seismic duct is constructed in this way, the force due to backfilling acts on the polyethylene resin pipe 4, and the right and left polyethylene resin pipes 4, 4 are twisted, so that the gate valve 2 as shown by the phantom line in FIG. May tilt. In this case, since the dissimilar pipe joints J and J have a relative rotation function, the inclined gate valve 2 can be returned to the original vertical state as shown by the solid line in FIG. it can. By the way, according to the experiment of the rotational performance after tightening the valve in the prototype, it cleared the test standard that “the valve can be rotated by hand with the polyethylene resin fixed after attaching the valve”, and the handle 21 has a load of 17 kgf. By adding, it was possible to return the tilted gate valve 2 to the original vertical state.

  After the pipe is fixed, if the male screw outlet 61, 61 of the metal joint body member 6 is not sufficiently tightened into the metal screw joint 22 of the gate valve 2, and the water pressure test leaks the pipe, the pipe is fixed. Retightening of the screws is required while remaining in the state. In this case, since the dissimilar pipe joints J and J have a relative rotation function, the male screw outlet of the metal joint body member 6 on one end side of the dissimilar pipe joints J and J using a pipe wrench while the pipe is fixed. By turning 61, 61, the screw can be tightened. In this point, in the trial experiment of screw tightening workability in the prototype, it clears the test standard that “the polyethylene resin part can be fixed and the male screw port can be rotated with a pipe wrench”, and the screw can be tightened. It was confirmed that there was.

  In order to construct an earthquake-resistant pipeline, durability performance is required so that the components of the joint will not come off and be damaged even if a large tensile force is applied in the tube axis direction due to an earthquake. On the other hand, since the dissimilar pipe joint J is not a tapered surface fitting structure but a vertical surface fitting structure to the flange 52 of the polyethylene adapter 5, even if a large tensile force is applied in the pipe axis direction, the polyethylene resin The pipe 4 is broken, and there is no weak point in the joint part, so that an earthquake resistant pipe line can be constructed. By the way, according to the original pipe tensile test with the prototype, the test standard of “The pipe breaks” was cleared, and when the tensile force was applied and the tensile force became 3.24kN, the pipe was confirmed to be broken.

  In the dissimilar pipe joint J of Example 1, the clearance C between the nut inner diameter D ′ of the cap nut 7 and the adapter outer diameter D ″ of the polyethylene adapter 5 is minimized, and the nut length L is about half of the adapter inner diameter. For this reason, even if the pipe system having the joint is greatly bent, the opening of the seal surface can be suppressed and water leakage can be prevented.By the way, using a prototype, a bending water pressure resistance test of the pipe line as shown in FIG. As a result, it cleared the test standard of “bending one side 22.5 degrees and adding water pressure 1.0MPa”, and even if bending one side 33 ° and applying water pressure 1.0MPa, the seal surface did not open. This means that the sealing performance can be maintained in the event of an earthquake in which a large bending force acts, and the earthquake resistance is excellent.

  In the first embodiment, after the cap nut 7 is tightened with a torque within a predetermined torque range with respect to the parallel threaded portion 63 of the metal joint body member 6, the bottomed pin hole 10 is formed in the cap nut 7 and penetrated. The locking pin 9 is incorporated in the hole 66 and the bottomed pin hole 10. Thus, after screwing the cap nut 7 into the parallel threaded portion 63 of the metal joint main body member 6, in order to hit the non-rotating pin 9 that prevents the metal joint main body member 6 and the cap nut 7 from rotating, Even if vibration or the like is applied to the dissimilar pipe joint J, the screw fitting portion between the metal joint body member 6 and the cap nut 7 does not loosen.

  In addition, the non-rotating pin 9 uses the pin diameter d of the pin portion 92 as a virtual torque that is applied to the pin portion 92 when the pinning operation is performed, and the tightening operation is performed based on the virtual torque. Is set to a diameter that does not break. For this reason, even if a site worker mistakenly performs a tightening operation to rotate the polygonal surface 73 of the cap nut 7 with a pipe wrench, the rotation prevention pin 9 does not break, and the metal joint body member 6 and the cap nut 7 The loosening prevention of the screw fitting part is ensured.

Next, the effect of the present invention will be described.
In the dissimilar pipe joint J of Example 1, the effects listed below can be obtained.

  (1) Cylindrical shape, having a first pipe connecting part for connecting a synthetic resin pipe member on one side and a polyethylene adapter 5 having a flange 52 on the opposite side, and a second pipe for connecting a metal pipe member on one side A metal having a connecting portion and having a first contact surface 62 in surface contact with a flange outer end surface 53 of the polyethylene adapter 5 on the opposite side, and a parallel threaded portion 63 having an inner diameter larger than the flange outer diameter of the polyethylene adapter 5 The joint body member 6, the cap nut of the polyethylene adapter 5 having a second contact surface 72 that is screw-fitted to the parallel threaded portion 63 and is in surface contact with the flange inner end surface 54 of the polyethylene adapter 5. A seal ring (O-ring 8) mounted on a seal-ring groove (O-ring groove 64) formed on one of the first outer surface 53 and the first contact surface 62 of the metal joint body member 6; The cap nut 7 is screw-fitted to the parallel threaded portion 63 of the metal joint body member 6 with a tightening torque within a predetermined torque range, and the maximum torque range that is assumed as the predetermined torque range. The lower limit torque required for sealing the water pressure is the minimum torque value of the cap nut tightening torque, and relative to the polyethylene adapter 5 when human power is applied to the metal pipe member connected to the metal joint body member 6 from the outside. The upper limit torque capable of rotation was set within the range of the maximum torque value of the cap nut tightening torque. For this reason, while the number of parts is small and the number of parts is small and the structure is simple and inexpensive, both the seal function by torque management and the relative rotation function are compatible, the fluctuation of the seal pressure due to the influence of external force in the axial direction, and the construction of an earthquake resistant pipe Can be achieved together. With this sealing function, fluid leakage can be prevented even when the assumed maximum internal water pressure is applied. In addition, the polyethylene adapter 5 and the metal joint main body member 6 can be returned to the normal positional relationship only by applying human power by the relative rotation function.

(2) The cap nut 7 has a predetermined torque range, the cap nut tightening torque is T (kgf · cm), and the polyethylene resin pipe outer diameter is D (cm).
0.5D ³ ≦ T ≦ 1000
The range represented by the formula of For this reason, the torque range of the initial tightening torque of the cap nut 7 that satisfies both the sealing function and the relative rotation function can be defined based on the polyethylene resin pipe outer diameter D.

(3) The cap nut 7 has a predetermined torque range, when the cap nut tightening torque is T (kgf · cm) and the polyethylene resin pipe outer diameter is D (cm),
1.5D ³ −100 ≦ T ≦ 1.5D ³ +100
The optimum torque range expressed by the formula For this reason, the torque range of the tightening torque of the cap nut 7 that maintains both the sealing function and the relative rotation function over a long period of time can be defined based on the polyethylene resin pipe outer diameter D.

  (4) The cap nut 7 is tightened with a torque within a predetermined torque range with respect to the parallel threaded portion 63 of the metal joint body member 6, and then a through hole 66 formed in the metal joint body member 6 A communicating radial hole (bottomed pin hole 10) is formed in the cap nut 7, and an anti-rotation member (non-rotating pin 9) is incorporated in the through hole 66 and the radial hole (bottomed pin hole 10). . Therefore, even if vibration or the like is applied to the dissimilar pipe joint joint J in the construction state, the screw fitting portion between the metal joint body member 6 and the cap nut 7 is not loosened, and the cap nut 7 is tightened within a predetermined range. Torque can be maintained.

  (5) The polyethylene adapter 5 is a member for connecting the polyethylene resin pipe 4 as a synthetic resin pipe member to the first pipe connecting portion by the cylindrical outer peripheral surface 51, and the metal joint body member 6 is partitioned as a metal pipe member. It is a member for connecting the metal screw joints 22 and 22 of the valve 2 to a second pipe connecting portion (male screw outlet 61) having a screw structure, and the cap nut 7 is connected to the handle 21 of the gate valve 2 from the outside. The upper limit torque that allows relative rotation when human power is applied is the maximum torque value of the cap nut tightening torque. Therefore, when the pipe diameter is twisted due to backfilling or the like and the gate valve 2 is tilted, the joint is rotated relative to the handle 21 of the gate valve 2 simply by applying a manual force to return the gate valve 2 to the normal position. be able to.

  (6) The cap nut 7 has a clearance C between the nut inner diameter D ′ and the adapter outer diameter D ″ that is set to an interval that combines the variation absorption amount and the minimum gap amount, and the nut axial length L is set. The length is set to about half the adapter inner diameter of the polyethylene adapter 5. Therefore, even if the pipe system having the joint is bent greatly, the seal surface can be prevented from opening, water leakage can be prevented, and the earthquake resistance is excellent. .

  (7) The seal ring is an O-ring 8 attached to an O-ring groove 64 formed in the first contact surface 62 of the metal joint body member 6, and after the O-ring 8 is attached to the O-ring groove 64, the seal ring The polyethylene adapter 5 and the metal joint body member 6 are integrated by applying a material and then tightening the cap nut 7. For this reason, the relative rotation of the polyethylene adapter 5 and the metal joint main body member 6 can be made smooth while the O-ring 8 exhibiting high sealing performance by crushing and deforming the seal ring.

  (8) The anti-rotation member is inserted into the screw-in head 91 that is screwed in the through hole 66 having the thread groove of the metal joint body member 6 and the bottomed pin hole 10 of the cap nut 7. A non-rotating pin 9 having a pin portion 92, and the non-rotating pin 9 is configured to tighten the pin diameter d of the pin portion 92 by a site builder rotating the polygonal surface 73 of the cap nut 7 with a pipe wrench. Assuming the operation, the torque acting on the pin portion 92 when the tightening operation is performed is set as a virtual torque, and the diameter is set so as not to break even if the tightening operation is performed based on the virtual torque. For this reason, even if a site operator mistakenly performs the tightening operation of rotating the polygonal surface 73 of the cap nut 7 with a pipe wrench, the breakage of the locking pin 9 that prevents the screw nut 7 from loosening the screw is avoided. be able to.

  As mentioned above, although the dissimilar pipe joint of this invention has been demonstrated based on Example 1, it is not restricted to this Example 1 about a concrete structure, The invention which concerns on each claim of a claim Design changes and additions are allowed without departing from the gist.

  In Example 1, the example which uses the non-rotating pin 9 as a non-rotating member was shown. However, any anti-rotation member other than the anti-rotation pin 9 may be used as long as the metal joint body member 6 and the cap nut 7 are integrated after the cap nut 7 is tightened.

  In Example 1, the example which uses O-ring 8 as a seal ring was shown. However, a mechanical seal having another structure may be used as long as the sealability of the synthetic resin adapter and the metal joint main body member 6 is ensured and relative rotation is allowed. Moreover, the surface which sets a seal ring is good also as a synthetic resin adapter side instead of the metal joint main body member 6 side. Moreover, you may set the sliding sheet | seat etc. which improve the sliding of a seal ring in the opposing surface of the surface with which the seal ring was mounted | worn.

  In Example 1, although the example which applies the dissimilar pipe joint J of Example 1 as a joint of the polyethylene resin pipe to the gate valve which constructs an earthquake-resistant pipe line was shown, as a joint of a normal pipe which has a dissimilar pipe Of course, it can be applied.

It is a general view which shows an example of the earthquake-resistant pipe line which applied the dissimilar pipe joint F of Example 1 as a coupling of the polyethylene resin pipe to a gate valve. 1 is an overall cross-sectional view showing a dissimilar pipe joint J of Example 1. FIG. 2 is a cross-sectional view showing a polyethylene adapter in the dissimilar pipe joint J of Example 1. FIG. The metal joint main body member in the dissimilar pipe joint J of Example 1 is shown, (a) shows sectional drawing, (b) shows a right view. The cap nut in the dissimilar pipe joint J of Example 1 is shown, (a) shows a left view, (b) shows sectional drawing. FIG. 4 is a cross-sectional view of a main part showing a screwed state of a detent pin in the dissimilar pipe joint J of Example 1. It is sectional drawing which shows an example of the conventional dissimilar pipe joint. It is a figure which shows the state which joined the short pipe part with the EF socket, when constructing | assembling an earthquake-resistant pipe line using the conventional dissimilar pipe joint. It is a figure which shows the state in which the handle of the gate valve inclined to the inner surface of the gate valve box by the twist of the pipe | tube by backfilling. It is sectional drawing which shows an example of the coupling with a rotation mechanism which added the rotation mechanism to the conventional different type pipe joint. It is a torque relationship characteristic figure which shows the relationship between the cap nut fastening torque for demonstrating the range of a required cap nut fastening torque, and a metal joint main body rotational torque. It is principal part sectional drawing which shows the state which completed the assembly of the dissimilar pipe joint F of Example 1 in a factory. It is explanatory drawing of the return effect | action which returns the gate valve inclined by the twist of the pipe | tube by backfilling to the original perpendicular state only by applying a human power to a handle. It is explanatory drawing which shows the bending water pressure test of the pipe line using the dissimilar pipe joint F of Example 1.

Explanation of symbols

J Heterogeneous pipe joint 1 Gate valve box 2 Gate valve (metal pipe member)
21 Handle 22 Metal screw joint 3 EF socket 4 Polyethylene resin pipe (synthetic resin pipe member)
5 Polyethylene adapter (synthetic resin adapter)
51 Cylindrical outer peripheral surface (first pipe connection part)
52 collar part 53 collar outer end face 54 collar inner end face 6 metal joint body member 61 male screw outlet (second pipe connection part)
62 1st contact surface 63 Parallel thread part 64 O ring groove (seal ring groove)
65 Polygonal surface 66 Through hole 7 Cap nut 71 Male thread portion 72 Second contact surface 73 Polygonal surface 8 O-ring (seal ring)
9 Non-rotating pin (non-rotating member)
91 Screwed head 92 Pin 10 Bottomed pin hole (Diameter hole)

Claims (6)

A synthetic resin adapter having a cylindrical shape, having a first pipe connecting portion for connecting a synthetic resin pipe member on one side, and a flange on the opposite side;
It has the 2nd pipe connection part which connects a metal pipe member to one side, and is larger than the 1st contact surface which is in surface contact with the collar outer end surface of the synthetic resin adapter on the other side, and the collar outer diameter of the synthetic resin adapter A metal joint body member having a parallel thread portion by an inner diameter;
A cap nut having a second contact surface that is screw-fitted to the parallel screw portion and is in surface contact with the inner end surface of the flange portion of the synthetic resin adapter,
A seal ring mounted on a seal ring groove formed on one surface of the first outer peripheral surface of the flange portion of the synthetic resin adapter and the first contact surface of the metal joint body member;
The cap nut is screw-fitted to the parallel thread portion of the metal joint body member with a tightening torque within a predetermined torque range, and seals the maximum internal water pressure assumed as the predetermined torque range. Is the minimum torque value of the cap nut tightening torque, and the upper limit torque that allows relative rotation with respect to the synthetic resin adapter when human force is applied to the metal pipe member connected to the metal joint body member from the outside. Set to the range of maximum torque value of cap nut tightening torque ,
The cap nut is tightened with a torque within a predetermined torque range with respect to the parallel thread portion of the metal joint body member, and then the radial hole communicating with the through hole formed in the metal joint body member is formed in the bag. A heterogeneous pipe joint , which is formed on a nut and has a detent member incorporated in the through hole and the radial hole . In the dissimilar pipe joint described in claim 1,
The cap nut has a predetermined torque range, when the cap nut tightening torque is T (kgf · cm) and the outer diameter of the synthetic resin pipe connected to the synthetic resin adapter is D (cm),
0.5D ³ ≦ T ≦ 1000
A dissimilar pipe joint, characterized in that it is set within the range represented by the formula: In the dissimilar pipe joint described in claim 2,
The cap nut has a predetermined torque range, when the cap nut tightening torque is T (kgf · cm) and the outer diameter of the synthetic resin pipe connected to the synthetic resin adapter is D (cm),
1.5D ³ −100 ≦ T ≦ 1.5D ³ +100
The dissimilar pipe joint, characterized in that it is set within the optimum torque range represented by the formula The dissimilar pipe joint joint according to any one of claims 1 to 3,
The synthetic resin adapter is a member that connects a polyethylene resin pipe as a synthetic resin pipe member to a first pipe connection portion by a cylindrical outer peripheral surface,
The metal joint body member is a member that connects a metal screw joint portion of a gate valve as a metal tube member to a second pipe connection portion by a screw structure,
The heterogeneous pipe joint is characterized in that the cap nut has a maximum torque value of cap nut tightening torque as an upper limit torque capable of relative rotation when external force is applied to the handle of the gate valve from the outside. The dissimilar pipe joint joint according to any one of claims 1 to 4,
For the cap nut, the clearance between the nut inner diameter and the adapter outer diameter is set to an interval that combines the variation absorption and the minimum gap, and the nut axial length is about half of the adapter inner diameter of the synthetic resin adapter. A heterogeneous pipe joint that is set to a length of The dissimilar pipe joint joint according to any one of claims 1 to 5,
The seal ring is an O-ring attached to an O-ring groove formed on the first contact surface of the metal joint body member,
A heterogeneous pipe characterized in that the synthetic resin adapter and the metal joint body member are integrated by applying a lubricant after attaching an O-ring to the O-ring groove and then tightening the cap nut. Joint joint.

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