JPH0648239Y2 - Connection structure of coated stainless steel pipe - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure of a coated stainless steel pipe suitable for connection of a liquid or gas supply pipe used for air conditioning, hot water supply, water supply, gas supply and the like.

[0002]

2. Description of the Related Art Conventionally, an iron pipe or a copper pipe has been used as a supply pipe used in a liquid or gas supply facility. However, the iron pipe has a drawback that rust occurs, and the copper pipe produces patina. There are drawbacks. In addition, iron pipes and copper pipes do not look good,
There is also an aesthetic problem that it is not suitable to be exposed in a general household. Therefore, it has been practiced to use stainless steel pipes instead of iron pipes and copper pipes depending on the pipe location. Then, the connecting direction of the stainless steel pipe is a screw type, and the socket fitted to the ends of the pair of pipes to be connected is tightened with a tightening nut such as a cap nut, or fitted to the ends of the pair of pipes. It is known to crimp the socket with a dedicated tightening tool.

[0003]

By the way, the above-mentioned prior art has the following drawbacks. First, since the surface of the pipe is in direct contact with the outside air, dew condensation is likely to occur on the surface of the pipe which is in contact with the cold air in a cold region, and the pipe is easily frozen. Secondly, since the stainless steel pipe is thinner than the iron pipe and the copper pipe, it is easily bent, and unnecessary force is applied to the connecting portion of the pipe to impair the gas-liquid tightness.
Further, in the above-mentioned pipe connecting method, when the pipe is deformed by expansion due to water pressure or freezing or thermal expansion, a gap is formed between the pipe and the socket, and the gas-liquid tightness is impaired. is there. Further, since the socket and the tightening nut are in a state of protruding from the outer peripheral surface of the pipe, there is a drawback that the appearance is poor. On the other hand, a stainless steel pipe whose outer surface is coated with vinyl chloride is also known, but it has a drawback that the gas-liquid tightness cannot be completely maintained as in the above because the connection of the pipe is a screw type. The present invention has been made in view of the above-mentioned drawbacks of the prior art, and is a coated stainless steel which is capable of preventing dew condensation and freezing of a stainless steel pipe, improving strength, and ensuring gas-liquid tightness at a connecting portion. An object is to provide a connection structure for steel pipes.

[0004]

Means for Solving the Problems The means of the present invention configured to solve the above-mentioned problems is to form a diameter-increasing step portion on the inner side of the pipe end side and to form an inner peripheral surface of the diameter-increasing step portion. An O-ring fitting groove is provided around the O-ring fitting groove, and an O-ring is fitted in the O-ring fitting groove, and an outer peripheral surface of the one-side stainless steel pipe is attached to the one end of the pipe end. A one-sided connecting pipe is composed of a thermoplastic synthetic resin coating layer whose axial end face formed to be flush with the end face is one side heat-welding face, and at least one shaft end side is the one-sided stainless steel pipe. Of the other side stainless steel pipe body which has become the insertion pipe portion that is press-fitted and inserted against the elasticity of the O-ring in the expanded step portion of the body, and the other side stainless steel pipe body except the outer peripheral surface of the insertion pipe portion. Heat applied to the outer peripheral surface and the axial end face facing the heat welding surface becomes the other heat welding surface. The other side connecting pipe is composed of the plastic synthetic resin coating layer, and the one side connecting pipe and the other side connecting pipe are connected by heating the one side and the other side heat-welding surfaces to weld each other. There is something I did. Further, the means of the second invention is to form an enlarged diameter step portion inside the pipe end side, and to provide an O-ring fitting groove around the inner peripheral surface of the enlarged diameter step portion, A one-sided stainless steel pipe body fitted with an O-ring, and a tubular fitting part that is attached to the outer peripheral surface of the one-sided stainless steel pipe body and projects outward in the axial direction with respect to the end face of the pipe end. A one-sided connecting pipe is constituted by a synthetic resin coating layer having an inner peripheral surface and an end surface serving as an adhesive surface, and at least one shaft end side has a resistance to the elasticity of the O-ring inside the expanded step portion of the one-sided stainless steel pipe body. The other side stainless steel pipe body that has become the insertion pipe part that is press-fitted and inserted, and the insertion cover part that has the outer peripheral surface that becomes the adhesive surface and is inserted into the tubular fitting part and the step that becomes the adhesive surface A large-diameter covering portion formed on the other side in the axial direction of the insertion covering portion via a surface, and the outer side surface of the insertion pipe portion is excluded except for the outer peripheral surface. The other side connecting pipe is composed of a synthetic resin coating layer applied to the outer peripheral surface of the stainless steel pipe body, and when the one side stainless steel pipe body and the other side stainless steel pipe body are inserted and fitted, It is configured such that the one side connecting pipe and the other side connecting pipe are connected by adhering the inner peripheral surface and the end surface to the outer peripheral surface and the stepped surface of the insertion covering portion.

[0005]

In the first aspect, the polyethylene coating layer of the one-side connecting pipe and the polyethylene coating layer of the other-side connecting pipe are welded to form an integral coating layer. In the second invention, the synthetic resin coating layer of the one-sided connecting pipe and the synthetic resin coating layer of the other-sided connecting pipe are bonded to form an integral coating layer.

[0006]

Embodiments of the present invention will be described in detail below with reference to the drawings. 1 to 3 show a first embodiment. In FIG. 1, reference numeral 1 denotes a T-shaped pipe joint as one side connecting pipe. 2 shows a T-shaped stainless steel pipe body that constitutes the T-shaped pipe joint 1,
The T-shaped stainless steel pipe body 2 is located on the pipe ends 2A, 2A (only one of which is shown) side extending in the horizontal direction in the figure, and an enlarged diameter step portion 3 is formed on the inner periphery thereof. Reference numeral 4 denotes an O-ring fitting groove circumferentially provided in the middle of the expanded diameter step portion 3, and an O-ring 5 made of, for example, fluororubber is fitted in the O-ring fitting groove 4.

Reference numeral 6 denotes a polyethylene coating layer which covers the entire outer peripheral surface of the T-shaped stainless steel tubular body 2 to a thickness of about 3 to 4 mm, and the polyethylene coating layer has a density of, for example, 0.9 g / cm ³ or more. A heat-welding surface 6 which is formed of a foamed polyethylene layer and whose axial end surface is flush with the tube end 2A of the T-shaped stainless steel tube body 2.
It is A.

On the other hand, 7 shows the other side connecting pipe. Reference numeral 8 denotes a straight tubular stainless steel tube body that constitutes the other-side connecting tube 7, and the shaft end side of the stainless steel tube body 8 has an enlarged diameter step portion 3 of the one-side connecting tube 1.
Inserted tube portion 8A that is press-fitted against the elasticity of the O-ring 5
It has become. Reference numeral 9 denotes a polyethylene coating layer adhered to the outer peripheral surface of the stainless steel pipe body 8 except the outer peripheral surface of the insertion pipe portion 8A. The polyethylene coating layer 9 is a one-sided connecting pipe 1
Made of the same type as the polyethylene coating layer 6 of
It is formed to a thickness of 4 mm and its shaft end surface is a heat-welded surface 9A.
It has become.

FIG. 2 shows a socket 10 connected to the other side connecting pipe 7 in the same manner as the T-shaped pipe joint 1. Reference numeral 11 denotes a stainless steel tube body that constitutes the socket 10, and the shaft ends 11A and 11A of the stainless steel tube body 11 have enlarged diameter step portions 12 and 12, respectively.
It has become. Reference numerals 13 and 13 denote O-ring fitting grooves circumferentially provided in the middle of the enlarged diameter step portions 12 and 12, respectively.
An O-ring 5 is fitted in the ring fitting groove 13. 1
Reference numeral 4 denotes a polyethylene coating layer applied to the outer peripheral surface of the stainless steel pipe body 11 over the entire length. The end face in the axial direction of the polyethylene coating layer 14 is the same as the shaft ends 11A, 11A of the stainless steel pipe body 11, and the heat welding surface 14 is formed.
A and 14A.

This embodiment is constructed as described above. For example, when the socket 10 and the other side connecting pipe 7 are connected, the socket 10 is heated by using an electrothermal tool A for heating and melting as shown in FIG. After melting the heat-welded surface 14A and the heat-welded surface 9A of the other side connecting pipe 7, both the stainless steel pipe bodies 11 and 8 are promptly press-fitted to bring the heat-welded surfaces 14A and 9A into contact with each other. Then, when the heat-welded surfaces 14A and 9A are hardened, the socket 10 and the polyethylene coating layers 14 and 9 of the other-side connecting pipe 7 are integrally connected.

Next, FIG. 4 shows a second embodiment. In addition,
The same components as those of the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted. In the figure, 2
Reference numeral 1 denotes a socket, and the socket 21 is composed of a one-sided stainless steel tube body 11 and a synthetic resin coating layer 22 such as vinyl chloride adhered to the outer peripheral surface of the one-sided stainless steel tube body 11. Here, the synthetic resin coating layer 22 has a tubular fitting portion 23 that protrudes outward in the axial direction from the pipe end 11A of the one-sided stainless steel pipe body 11, and the inner peripheral surface 23A and the end surface 23B have an adhesive surface. It has become.

On the other hand, reference numeral 24 indicates a connecting pipe on the other side. The connecting pipe on the other side 24 is a vinyl chloride attached to the outer surface of the stainless steel pipe body 8 and the stainless steel pipe body 8 except the insertion pipe portion 8A. And a synthetic resin coating layer 25. Here, in the synthetic resin coating layer 25, the outer peripheral surface 26A serves as an adhesive surface, and the insertion coating portion 26 is inserted into the tubular fitting portion 22A.
And the insertion covering portion 26 through the stepped surface 27 serving as an adhesive surface.
Is integrally formed with the large-diameter coating portion 28 formed on the other side in the axial direction.

In the present embodiment having the above configuration,
When connecting the socket 21 and the other side connecting pipe 24, an adhesive is applied in advance to the inner peripheral surface 23A and the end surface 23B of the tubular fitting portion 23, the outer peripheral surface 26A of the insertion covering portion 26 and the stepped surface 27. , Both of the stainless steel pipe bodies 11 and 8 are press-fitted and the both synthetic resin coating layers 22 and 25 are adhered.

The thicknesses of the polyethylene coating layers 6, 9, 14 in the first embodiment and the synthetic resin coating layers 22, 25 in the second embodiment are the same as those of the stainless steel pipes 2, 8, 11 respectively.
It can be appropriately set according to the diameter, length, and purpose of use.

[0015]

Since the present invention is constructed as described in detail above, it has the following effects. Condensation and freezing can be prevented because the stainless steel tube does not come into direct contact with the outside air. Both the thermoplastic synthetic resin coating layers of the one-side connecting pipe and the other-side connecting pipe are heat-welded, and both synthetic resin coating layers can be integrally connected by bonding,
Even if the tube expands, the gas-liquid tightness can be completely maintained. For the same reason as above, the bending load of the tubular body can be received by the entire coating layer, and as a result, the amount of flexing of the tubular body can be reduced and deterioration of the O-ring can be prevented. The connecting portion of the one-side connecting pipe and the other-side connecting pipe can be made straight without recesses, and the appearance can be finished aesthetically. Since it is not necessary to thread the pipe, workability is excellent and it is possible to prevent the pipe from being contaminated by cutting oil and from having an offensive odor.
Since the coated stainless steel pipe according to the connection structure of the present invention has excellent impact resistance as compared with the vinyl chloride pipe, it can be used as a buried pipe. Conventionally, vinyl chloride pipes and polyethylene pipes used as buried pipes were not able to be detected by metal detectors, leading to pipe cutting accidents during excavation work.The connection structure of the present invention covered stainless steel pipes. By using as a buried pipe, it is possible to detect and prevent pipe cutting accidents.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a one-side connecting pipe and another-side connecting pipe according to a first embodiment of the present invention with a main part broken away.

FIG. 2 is a vertical cross-sectional view of a socket that serves as a one-sided connection pipe.

FIG. 3 is an explanatory diagram showing a method of connecting the one-side connecting pipe and the other-side connecting pipe.

FIG. 4 is an explanatory view showing a one-side connecting pipe and another-side connecting pipe according to a second embodiment with a main part broken away.

[Explanation of Codes] 1, 10, 21 One-sided connecting pipe 2, 11 One-sided stainless steel pipe body 3, 12 Expanded diameter stepped portion 6, 9 Polyethylene coating layer 6A, 9A, 14A Heat-welding surface 7, 24 Other-sided connecting pipe 8 Other Side Stainless Steel Tubing 8A Inserted Pipe Part 22, 25 Synthetic Resin Covering Layer 23 Cylindrical Fitting Part 23A, 23B, 26A, 27 Bonding Surface 26 Insertion Covered Part

Claims (2)

[Scope of utility model registration request] 1. An enlarged diameter step portion is formed on the inner side of the pipe end side, an O-ring fitting groove is provided around an inner peripheral surface of the enlarged diameter step portion, and an O-ring is fitted in the O ring fitting groove. And a one-sided stainless steel pipe body mounted on the outer peripheral surface of the one-sided stainless steel pipe body, and the axial end face formed to be flush with the end face of the pipe end is the one-side heat welded surface. The one-side connecting pipe is composed of the thermoplastic synthetic resin coating layer, and at least one shaft end side of the one-side stainless steel pipe body is press-fitted into the expanded-diameter step portion against the elasticity of the O-ring. The other side stainless steel pipe body that has become the insertion pipe part and the outer peripheral surface of the other side stainless steel pipe body except the outer peripheral surface of the insertion pipe part, and the axial end surface facing the heat welding surface is the other side heating The other side connecting pipe is composed of the thermoplastic synthetic resin coating layer which is the welding surface, and the one side and the other side are heat welded. A connection structure for a coated stainless steel pipe, wherein the one side connecting pipe and the other side connecting pipe are connected by heating the surfaces and welding each other. 2. An enlarged-diameter step portion is formed on the inner side of the pipe end side, an O-ring fitting groove is provided around the inner peripheral surface of the enlarged-diameter step portion, and an O-ring is fitted in the O-ring fitting groove. Mounted one side stainless steel tube body, and the inner peripheral surface and the end surface of the tubular fitting portion that is attached to the outer peripheral surface of the one side stainless steel tube body and projects outward in the axial direction with respect to the end surface of the pipe end. Forming a one-side connecting pipe from a synthetic resin coating layer having an adhesive surface, and at least one shaft end side of the one-side stainless steel pipe body is press-fitted against the elasticity of the O-ring against the elasticity of the O-ring. The other side stainless steel pipe body that has become the insertion pipe portion, the outer peripheral surface that serves as the bonding surface, and the insertion covering portion that is inserted into the tubular fitting portion and the stepped surface that serves as the bonding surface. A large-diameter coating portion formed on the other side in the axial direction of the insertion coating portion, and the stainless steel pipe body on the other side except the outer peripheral surface of the insertion pipe portion. The other side connecting pipe is composed of a synthetic resin coating layer adhered to the outer peripheral surface of, and when the one side stainless steel pipe body and the other side stainless steel pipe body are inserted and fitted, the inner peripheral surface of the tubular fitting portion And a connection structure of a coated stainless steel pipe configured to connect the one-side connection pipe and the other-side connection pipe by adhering the end face to the outer peripheral surface and the stepped surface of the insertion covering portion.