JPH08216262A - Connecting method for synthetic resin tube to tube joint - Google Patents

Abstract

PURPOSE: To provide a method for-connecting a synthetic resin tube to a tube joint without decreasing the durability of the joint due to the damage by hydraulic pressure or the operation of chemicals by reducing shrinkage stress due to heat and improving the hydraulic pressure resistance and the chemical resistance. CONSTITUTION: A method for connecting a hard vinyl chloride resin tube 3 to a tube joint 2 comprises the steps of heating to melt the inserting part 31 of the tube 3 and the tube socket 21 of the joint 2, inserting the tube 3 into the joint 2, and fusion bonding them, wherein the heating time of the tube socket of the joint 2 is lengthened 1.5 to 3 times as long as that of the inserting part of the tube 3, and the heating of the socket 21 is finished while the part 32 of the tube 3 is in a thermally molten state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of joining a synthetic resin pipe and a pipe joint by heat-sealing the synthetic resin pipe and the pipe joint.

[0002]

2. Description of the Related Art As a method of joining a synthetic resin pipe and a synthetic resin pipe joint, a pipe joint insertion portion of the synthetic resin pipe and a pipe receiving port of the pipe joint into which the synthetic resin pipe is inserted are heated and melted. A method of inserting and joining while in a molten state is used.

Generally, the same kind of synthetic resin is used for the synthetic resin pipe and the pipe joint. For this reason, since the melting temperature by heat is the same, the start and end of heating are almost simultaneously performed. This heating time is set so that if the synthetic resin pipe is overheated, it will be significantly softened and the synthetic resin pipe will buckle when it is inserted into the pipe joint.Therefore, it is necessary to heat the synthetic resin pipe within the range that does not cause buckling. Therefore, the pipe socket of the pipe joint was heated according to this heating time.

[0004]

Since the synthetic resin pipe and the pipe joint are thicker in the pipe joint,
When the insert portion of the synthetic resin pipe is heated and melted within the range where the buckling does not occur, the insert portion is sufficiently heated over the entire wall thickness. However, in a pipe joint having a thickness larger than that of a synthetic resin pipe, even if the inner surface of the pipe receiving hole is melted by heat, the entire wall thickness is not sufficiently heated.

Further, since the outer surface of the synthetic resin pipe is heated, the shrinkage stress after cooling is small, but since the inner surface of the pipe joint is heated, the shrinkage stress near the inner surface after cooling is large, and the inner diameter of the pipe joint is large. Causes a residual strain such that Therefore, the contraction stress concentrates on the pipe joint part that is the tip of the inserted synthetic resin pipe, and the strength against water pressure decreases, causing destruction, and in chemical liquid piping, the chemical action concentrates on the pipe joint part and cracks occur. However, there is a problem in that the life of the pipe joint is shortened.

The present invention solves the above-mentioned conventional problems, reduces shrinkage stress due to heating, improves water pressure resistance and chemical liquid resistance, and does not cause damage due to water pressure or decrease in durability of pipe joints due to the action of chemical liquid. An object is to provide a method for joining a synthetic resin pipe and a pipe joint.

[0007]

A method for joining a synthetic resin pipe and a pipe joint according to the present invention is to insert a synthetic resin pipe into a pipe joint by heating and melting an insertion portion of the synthetic resin pipe and a pipe receiving port of the pipe joint. In a method of joining a synthetic resin pipe and a pipe joint for fusion bonding, the heating time of the pipe socket of the pipe joint is made 1.5 to 3 times longer than the heating time of the insertion part of the synthetic resin pipe, and the insertion is performed. It is characterized in that the heating and melting of the pipe receiving port of the pipe joint is finished while the portion is in the heat melting state.

Examples of the synthetic resin pipes and pipe fittings used in the present invention include those made of thermoplastic resins such as vinyl chloride resin, chlorinated vinyl chloride resin, polyvinylidene fluoride, polyethylene and polypropylene.

The heating temperature of the synthetic resin pipe and the pipe joint is
The molding temperature of the resin is preferably (+10 to 60) ° C. The time for heating the pipe receiving port of the pipe joint is set to be 1.5 to 3 times as long as the time for heating the insertion portion of the synthetic resin pipe. The reason for this is that if the heating time is shorter than 1.5 times, the entire wall thickness of the pipe receiving port is not sufficiently heated, and after cooling, the shrinkage stress strongly acts on the inner surface of the pipe receiving port. Also, if the heating time exceeds three times, the pipe joint is likely to cause thermal decomposition.

The heating time of the pipe receiving port of the synthetic resin pipe and the insertion portion of the pipe joint is set as described above, and the pipe receiving port of the pipe joint is closed while the surface of the insertion portion of the synthetic resin pipe is in a molten state. It is necessary to finish the heating and melting and insert the synthetic resin pipe into the pipe joint. For this purpose, the heating time of the pipe joint of the pipe joint is set to the above set time, and the heating of the pipe joint is performed by adjusting the heating time of the insertion portion of the synthetic resin pipe and the heating end of the pipe joint. The heating may be started before the heating of the tube, and the heating of the synthetic resin tube may be started with a delay. However, the heating is not necessarily finished at the same time, and if the heating of the pipe joint is finished while the surface of the insertion portion of the synthetic resin pipe is in a molten state, the insertion portion of the synthetic resin pipe and the pipe receiving port of the pipe joint are It can be joined as a molten state.

[0011]

[Function] By making the heating time of the pipe receiving port of the pipe joint 1.5 to 3 times longer than the heating time of the insertion portion of the synthetic resin pipe,
Since the pipe receiving port of the pipe joint is sufficiently heated over the entire wall thickness, residual strain acting on the inner surface of the pipe receiving port after cooling is reduced and the water pressure resistance is improved. Further, since the heating of the pipe receiving port of the pipe joint is finished while the insertion portion of the synthetic resin pipe is in a heat-melted state, the insertion portion of the synthetic resin pipe and the pipe receiving port of the pipe joint are completely joined in a molten state. can do.

[0012]

Embodiments of the method of the present invention will now be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a method for joining a synthetic resin pipe and a pipe joint of the present invention, and 1 is a heater,
A tube heater 12 having a concave cross section is provided on one side of the main body 11, and a joint heater 13 is provided on the other side. The joint heater 13 is inserted into the pipe socket 21 of the pipe joint 2 and heated, and then the hard vinyl chloride resin pipe 3 is inserted into the pipe heater 12 to heat the surface of the insertion portion 31.

(Example 1) The heater 13 for joints and the heater 12 for tubes of the heater 1 were energized and heated to 245 ° C. Pipe fitting made of hard vinyl chloride resin (T for VP100
The above-mentioned joint heater 13 was inserted into one pipe receiving port 21 of the S socket 2 and heated for 60 seconds to melt the inner surface thereof. 40 seconds after the heating of the pipe joint 2 is started, a hard vinyl chloride resin pipe (VP100, inner diameter 100) is attached to the pipe heater 12.
mm, thickness 7 mm) 3 was inserted and the surface was heated and melted for 20 seconds. After that, pipe fitting 2 and hard vinyl chloride resin pipe 3
And were simultaneously extracted from the heater 1, and immediately, the hard vinyl chloride resin pipe 3 was inserted into the pipe joint 2 and cooled. Similarly, a hard vinyl chloride resin pipe was joined to the other pipe receiving port (not shown) of the pipe joint 2.

Example 2 Heating of the pipe joint 2 was started 3
After 0 seconds, the hard vinyl chloride resin tube 3 was inserted into the tube heater 12, and the resin tube 3 was joined to the pipe joint 2 in the same manner as in Example 1 except that the resin tube 3 was heated and melted for 30 seconds.

(Example 3) VP150 (inner diameter 150 mm, wall thickness 9.6 mm) as the hard vinyl chloride resin pipe 3,
The resin pipe 3 and the pipe joint 2 were joined in the same manner as in Example 2 except that a TS socket for VP150 was used as the pipe joint 2.

(Example 4) Heat-resistant vinyl chloride resin pipe (HT
100, inner diameter 100 mm, wall thickness 7 mm) and heat resistant pipe joint (TS socket for HT100, wall thickness 7 mm) were used and the heating temperature was set to 255 ° C. in the same manner as in Example 2 to obtain the resin pipe and pipe. Joined with the joint.

(Comparative Example 1) The resin pipe 3 and the pipe joint 2 were joined in the same manner as in Example 1 except that both the hard vinyl chloride resin pipe 3 and the pipe joint 2 were heated and melted for 20 seconds.

(Comparative Example 2) The hard vinyl chloride resin pipe 3 and the pipe joint 2 were joined in the same manner as in Comparative Example 1 except that the heating time was 30 seconds.

(Comparative Example 3) The resin pipe 3 and the pipe joint 2 were joined in the same manner as in Comparative Example 1 except that the heating time was 45 seconds.

Comparative Example 4 The resin pipe 3 and the pipe joint 2 were joined in the same manner as in Comparative Example 1 except that the heating time was 60 seconds.

In the above Examples 1 to 4 and Comparative Examples 1 to 4, a hydraulic fracture test was conducted by closing the ends of the pipes joined to both sides of the pipe joint. Table 1 shows the results.

[0022]

[Table 1]

In each of Examples 1 to 4, the pipes expanded and failed, but the pipe joints did not. However, Comparative Example 1
The pipes of Nos. 4 to 4 did not break, and the pipe joints all failed.
Further, as is clear from Table 1, it can be seen that the pipes of Examples 1 to 4 can maintain the excellent water pressure resistance of the pipe joint and the joint as compared with those of the comparative example.

[0024]

Since the method of joining the synthetic resin pipe and the pipe joint of the present invention has the above constitution, the shrinkage stress due to heating is reduced to improve the water pressure resistance and the chemical resistance, and the destruction by the water pressure and the action of the chemical Does not cause deterioration of durability of the pipe joint. Further, the insertion portion of the synthetic resin pipe and the pipe receiving port of the pipe joint can be completely joined in a molten state.

[0025]

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1: Heater 2: Pipe joint 3: Hard vinyl chloride resin pipe 11: Main body 12: Pipe heater 13: Joint heater 21: Pipe socket 31: Insertion part

Claims (1)

[Claims] 1. A method of joining a synthetic resin pipe and a pipe joint, wherein an insertion portion of the synthetic resin pipe and a pipe receiving port of the pipe joint are heated and melted, the synthetic resin pipe is inserted into the pipe joint and fusion-bonded, The heating time of the pipe receiving port of the pipe joint is set to be 1.5 to 3 times longer than the heating time of the inserting portion of the synthetic resin pipe, and the pipe receiving pipe of the pipe joint is held while the inserting portion of the synthetic resin pipe is in a heat-melted state. A method for joining a synthetic resin pipe and a pipe joint, characterized by terminating the heating and melting of the mouth.