JPS5933449B2 - Pipe joint joining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pipe joint joining method for joining metal pipes using thin joint fittings made of stainless steel or the like.

The method of joining metal pipes used for indoor piping etc. using fittings has been practiced for a long time, and the typical method is to cut female threads on the inner surface of both ends of the fittings, This method involves cutting a male thread on the outer periphery of the tip and screwing the pipe into the fitting to connect it.

However, this method requires the fitting to be thick enough to cut the threads, making it heavy as the fitting is made of cast iron, and also because the fitting and the pipe must be rotated relative to each other. There are problems in construction, and furthermore, there are some cases in which the airtightness, pressure resistance, etc. are not necessarily satisfactory. Therefore, a technique was developed in which the tip of the pipe was inserted into a fitting having an annular bulge containing an O-ring, and then the tip of the fitting was tightened with a bolt-nut type tightening piece to join the two. No. 11367. This method allows the use of thin fitting fittings and has the advantage that there is no need to rotate the fitting and the pipe relative to each other, but on the other hand, the O-ring can be damaged at the tip of the pipe when the tube is inserted into the fitting. This may lead to a decrease in airtightness, and since the pipe is fixed to the fitting only by frictional force, there are also problems in pressure resistance and thrust resistance.
The present invention solves the above-mentioned problems and provides a new pipe that has high airtightness, pressure resistance, and thrust resistance, and can be easily constructed at construction sites even by non-skilled workers. It was completed for the purpose of joint joining method, and the main body part has approximately the same diameter as the pipe to be joined, and an enlarged diameter part is formed through the annular bulge part.
After fitting an airtight material such as a ring, the end of the pipe to be joined is reduced in diameter to a tapered part smaller than that of the airtight material, and then inserted into the enlarged diameter part and the tapered part is inserted into the airtight material. and then partially pressurizing the outer periphery of the enlarged diameter part to form a plurality of recesses extending in the circumferential direction and biting into the front part of the pipe inserted into the enlarged diameter part. This is a characteristic feature.

The fitting used in the present invention can be of any type, such as a socket, elbow, tee, reducer, or cap. To explain the invention in more detail, 1 in the figure is a stainless steel plate with a wall thickness of 0.
It is a socket-shaped fitting with a thin wall of about 6 to 1.5 mwL, and is expanded through an annular bulge 5 having a semicircular cross section at the end of a main body 3 having approximately the same diameter as the pipe 2 to be joined. Diameter 4
The inner diameter of the enlarged diameter portion 4 is slightly larger than the outer diameter of the tube 2, and the tube 2 can be inserted therein. A step is formed at the connecting portion between the main body portion 3 and the enlarged diameter portion 4, and an annular bulging portion 5 is formed in this portion. To join the pipes 2, 2 with the fitting 1, first attach an airtight material 6 such as an O-ring to the enlarged diameter part 4 of the fitting 1.
1 and fit it into the annular bulge 5 as shown in FIG.
Next, the pipe 2 to be joined is inserted into the enlarged diameter part 4 of the fitting, and the tip of this pipe 2 has a tapered part 7 with a slightly smaller diameter than the airtight material 6, as shown in FIG. Make the diameter smaller. When this pipe 2 is inserted into the enlarged diameter part 4 of the fitting 1, the tapered part 7 at the tip of the pipe 2 comes into contact with the airtight material 6 such as an O-ring, and the annular bulging part 5 The tapered part 7 and the airtight material 6 are brought into close contact with each other due to the elasticity of the airtight material 6, and at the same time, the tip of the pipe 2 is pushed into the vicinity of the boundary between the main body 3 of the fitting 1 and the broken bulge 5. They are abutted and positioned. The tip of the tube 2 is reduced in diameter to a tapered part 7 that is smaller in diameter than the airtight material 6, so when inserting it into the enlarged diameter part 4 of the fitting 1, do not touch the side of the airtight material 6 such as an O-ring. There is no risk of damage to the airtight material 6 during insertion. When the pipe 2 is brought into close contact with the airtight material 6 in this way, the enlarged diameter part 4 of the joint fitting 1 into which the pipe 2 is inserted
The outer periphery of is strongly pressed by press tools 8 and 9. In this embodiment, four press tools are arranged around the enlarged diameter portion 4 at 90 degree intervals, but the number of press tools may be plural and is not limited to four. These press tools 8 and 9 are strongly pressed against the surface of the enlarged diameter part 4 by manual or hydraulic force, plastically deforming the contact parts, and inserted into the enlarged diameter part 4 as shown in FIG. pipe 2
Four recesses 10 are formed. These recesses 1
0 extends in the circumferential direction, and its depth can be changed appropriately by adjusting the shape of the press tool, the pressing force, etc. As a result of the plurality of recesses 10 formed in the enlarged diameter part 4 of the fitting fitting 1 biting into the pipe 2 inserted into the enlarged diameter part 4 in this way, the fitting fitting 1 and the tube 2 are separated from each other at the tip of the tube 2. The tapered portion 7 of the portion is firmly fixed in close contact with the airtight material 6. In this way, in the method of the present invention, after fitting the airtight material 6 such as an O-ring to the annular bulge 5 of the fitting 1, the pipe 2 whose tip has been previously reduced in diameter to the tapered portion 7 is inserted into the fitting 1. Since the airtight material 6 such as an O-ring is inserted into the enlarged diameter part 4 of the ring, the airtight material 6 such as an O-ring is smoothly pushed into the annular bulged part 5, and since the tip of the ring 2 has a smaller diameter than this airtight material 6, it is airtight when inserted. The material 6 is not damaged by the tip of the tube 2, and good airtightness can be obtained.

In addition, since the airtight material 6 is forcefully expanded outward by the tapered portion 7 and pressed against the annular bulging portion 5, its elasticity causes the pipe 2 and the fitting 1 to come into close contact with each other, resulting in airtightness. further improve. Moreover, this fitting 1 has a main body part 3 having approximately the same diameter as the pipe 2, and has a structure in which an annular bulge part 5 is formed at the connection part between the main part 3 and the enlarged diameter part 4. 2 is inserted, its tapered part 7 comes into close contact with the airtight material 6, and it is impossible to insert it beyond the position where its tip contacts the main body part 3, so that a good positioning effect can be obtained. Note that since the tip of the tube 2 is reduced in diameter to the tapered part 7, the flow resistance will increase in this part, but since it is only necessary to reduce the tube diameter by about 5%, the increase in flow resistance will be reduced. The pressure loss due to this is negligible. Furthermore, in the method of the present invention, the enlarged diameter portion 4 of the fitting 1 is pressurized from the outside with a press tool or the like to form a plurality of recesses 10 that bite into the pipe 2 inserted into the enlarged diameter portion. Since the fitting 1 and the pipe 2 can be fixed together, there is no need to apply relative rotation between the fitting and the pipe when joining, unlike when using a conventional screw-in fitting. Since a concave part is formed in the joint, it is possible to confirm that the joint has been completed, and there is no risk of forgetting to tighten the screws as in the case of a screw-in type, so it can be easily installed at the construction site even by non-skilled workers. Moreover, since there is no need to cut threads in the joint fitting 1, the wall can be made thinner and lighter, and the joining cost can be significantly reduced. J can do it. In addition, in the method of the present invention, a recess 1 extending in the circumferential direction in the enlarged diameter portion 4 of the joint fitting 1 is provided.
0, it can withstand the thrust load in the axial direction of the tube well, and since a plurality of recesses 10 are formed,
It appears as if the enlarged diameter portion 4 and the pipe 2 inserted therein were plastically deformed into a polygonal shape, and can effectively resist torsional forces acting on the piping system. As is clear from the description of the embodiments described above, the present invention is superior in that it firmly fixes the pipe and the fitting in a state in which the pipe to be joined is brought into close contact with the airtight material fitted into the fitting. A pipe fitting that achieves airtightness, pressure resistance, and thrust resistance, and also has the advantages of easy construction and reduced joining costs, and solves the problems of conventional pipe fitting joining methods. This is an extremely significant bonding method that can be brought to the industry.

[Brief Description of the Drawings] The drawings are process explanatory diagrams of the method of the present invention. Fig. 1 is a partially cutaway front view showing the state in which the airtight material is fitted into the annular bulge of the fitting, and Fig. 2 is a diagram showing the state in which the airtight material is fitted into the annular bulge of the joint fitting. FIG. 3 is a partially cutaway front view showing a state in which the connector is inserted into the enlarged diameter part of the joint fitting, and FIG. 1: Fitting, 2: Pipe, 3: Main body, 4: Expanded diameter section, 5:
Annular bulging part, 6: Airtight material, 7 Re-tapered part, 10: Recessed part.

Claims (1)

[Claims] 1. After fitting an airtight material such as an O-ring into the annular bulge of a fitting that has an enlarged diameter section formed through an annular bulge in the main body having approximately the same diameter as the pipe to be joined, the pipe is to be joined. A pipe whose tip is reduced in diameter to a tapered part smaller than the airtight material is inserted into the enlarged diameter part to bring the tapered part into close contact with the airtight material, and then the outer periphery of the enlarged diameter part is partially cut. A method for joining a pipe joint, characterized in that a plurality of recesses extending in the circumferential direction are formed by pressurizing the pipe into the front part of the pipe inserted into the enlarged diameter part.