JPH074385Y2 - Inner and outer surface resin coated joints - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to an electrically insulating pipe joint having an inner and outer surface coated with a resin, which is mainly used for connecting an inner surface resin-lined steel pipe used for a water pipe to a copper alloy pipe part or the like.

[Prior art]

In piping for water, when connecting a copper alloy water tap and a cast iron pipe fitting, different metals of the copper alloy and cast iron come into contact at the connection portion, so electrolytic corrosion caused by the battery action during use may occur. Occur. Therefore, as a pipe joint for electrically insulating this connecting portion, there is a pipe joint disclosed in Japanese Utility Model Laid-Open No. 63-129785. As shown in FIG. 6, this is a cast iron joint body 10 having a substantially cylindrical shape and having a female thread 11 for pipe on one inner peripheral surface of one end and a female thread 12 on the inner peripheral surface of the other end, except for the female thread 11 for pipe. A resin coating portion (20) is formed on the inner peripheral surface, and a female thread (21) for pipe is formed by the resin coating portion (20) on the inner peripheral surface coated with the female thread (12) and a female thread for pipe (11) is provided.
A cylindrical portion 22 made of a resin coating portion 20 is integrally formed with a pipe internal thread 11 and a gap provided on the side. And the fitting body
Female thread for pipe 21 by inner resin coating 20 provided on the inner surface of 10
Thus, the pipes connected to the female pipe thread 11 and the female pipe thread 21 are connected.

[Problems to be solved by the device]

However, in the above conventional pipe joint, the female thread 21 for pipes connected to the copper alloy piping parts, etc. is a resin thread, so the strength of the thread is weak, and when the male thread made of copper alloy is strongly screwed in, the female thread made of resin is There was a problem that 21 was destroyed and could not be connected, or leakage occurred at this connection part. Also, since the outer surface of the cast iron joint body 10 is exposed, the joint body will not be exposed if it is piped in a place exposed to rainwater or in buried soil.
There is a problem that the outer surface of 10 corrodes. In addition, since the outer surface of the fitting body 10 is exposed and is connected in close proximity to the copper alloy piping parts that are piped to it, there is a problem that the fitting is externally conducted due to the influence of the humidity environment outside the fitting. It was In view of this, the present invention provides insulation between dissimilar metal pipes such as steel pipes and copper alloy pipe parts, etc. to prevent corrosion from internal and external corrosive environments, and to connect to both sides of joints, forcibly, due to external moisture environment. Provided is an electrically insulating joint for water pipes in which continuity between pipes is prevented.

[Means for Solving the Problems]

The gist of the present invention is a substantially cylindrical shape, an outer joint body made of cast iron having a female thread for a pipe connected to a resin-lined steel pipe at one end and an assembling female thread at the other end, and a substantially cylindrical shape, The outer peripheral surface of one end has a smooth portion, an external thread for assembling into the internal thread for assembling the outer joint body, and an external thread for assembly followed by a side surface in the direction perpendicular to the axis. The inner joint body made of a copper alloy of a dissimilar metal and the outer joint body having a pipe thread to be connected to the inner joint surface of the outer joint body excluding the pipe female thread and the female thread for assembly are covered with a resin. An inner surface covering portion having a smooth inner peripheral surface that circumferentially overlaps with a smooth portion of the inner joint body, and a cylindrical portion extending from the inner surface covering portion to the female thread side for the pipe and covering the inner peripheral surface of the connecting lining steel pipe. A resin coating layer having an inner surface, and an internal thread for assembling the outer joint body An electrical insulating layer coated with resin on at least one surface of the male thread for assembling the inner joint body, a screw coated with the electrical insulating layer, and a screw threaded to the screw, and an inner joint member An adhesive layer for adhering the inner surface and the inner surface coating portion, and an outer surface resin coating layer coated with a resin that covers the outer surface of the outer joint body and a resin for an annular ring that covers the assembly side end surface of the outer joint body, By screwing the outer joint body and the inner joint body with an adhesive layer, the annular ring of the outer resin coating layer is sandwiched between the end surface of the outer joint body and the side surface of the inner joint body and sealed and fixed by the adhesive layer. In addition, the inner / outer surface resin-coated joint is characterized in that the inner surface of the outer joint body is continuously covered with the inner surface resin coating layer, the inner joint body, and the adhesive layer from the internally flowing water to be blocked.

[Action]

Since the present invention has the above-mentioned configuration, the lining steel pipe connected to the female thread for pipe of the outer joint body and the copper alloy pipe part connected to the inner joint body are connected to either of the inner and outer joint body assembly screws. It is electrically insulated by the coated electrically insulating layer. The outer surface of the outer joint body is covered with an outer surface resin coating layer, and the end face of the outer joint body on the assembly side is also covered with an annular ring of the outer surface resin coating layer. Sealed and fixed with an adhesive, the outer joint body is shielded from the external corrosive environment. For this reason, conduction between the outer joint body and the inner joint body due to the external moisture environment is prevented, so it is isolated from the influence of the external environment between the pipes connected to both the inner and outer joint bodies, and the influence of the external moisture environment etc. Conduction between the connecting pipes is also prevented. Further, the inner surface of the lining steel pipe is covered with the cylindrical portion of the inner surface resin coating layer, and the smooth portion of the inner joint main body and the smooth inner peripheral surface of the inner surface coating portion that overlaps the inner surface of the inner joint body are sealed with an adhesive layer to form an inner resin coating layer. Since the inner joint body and the inner joint body are continuously covered, the end surface of the connected lining steel pipe and the outer joint body are also shielded from the circulating water in the interior to prevent corrosion. In addition, the material of the pipe thread of the outer joint body and the inner joint body that is connected to the pipe is the same type of metal screw as the pipe, both connection screws have sufficient strength, and the pipe connection can be done without any problems in screwing connection. I can.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a resin-coated joint for inner and outer surfaces showing a first embodiment of the present invention, and FIGS. 2 to 4 show second to fourth embodiments, respectively, which will be described according to the manufacturing procedure. To do. Reference numeral 1 denotes an outer joint body, which is a malleable cast iron screw-type socket joint in the first and second embodiments, an elbow joint in the third embodiment, and a cheese joint in the fourth embodiment. Synthetic resin, for example vinyl chloride resin, is injection-molded on the inner surface of the outer joint body 1 to cover the inner surface of the lining steel pipe connected to the female pipe thread 1a for connection with the pipe, and the cylindrical portion 2c. An inner surface resin coating layer 2 having an inner surface coating portion 2b integrally covering the inner surface of the central portion excluding the female threads for pipe 1a on both sides and the female thread for assembly 1b is provided. In this way, the joint body 1 provided with the inner surface resin coating layer 2
Then, a synthetic resin such as vinyl chloride resin is injection-molded with another mold to provide the outer surface resin coating layer 7. The outer surface resin coating layer 7 covers the outer peripheral surface of the joint body 1 and projects to the end portion on the connection side with the pipe to form a cylindrical body that covers the outer surface of the connection steel pipe. An annular ring 6 is formed to cover it. Reference numeral 3 denotes an inner joint body made of a copper alloy, a smooth portion on the outer surface of the end portion on the assembly side, an assembling male screw 3b screwed into the assembling female screw 1b of the outer joint body 1, and subsequently a direction perpendicular to the axis. Has a side surface 3d, and the other end is provided with a pipe screw for connection with a copper alloy pipe fitting. This pipe thread is provided with a male pipe thread 3a in the first, third and fourth embodiments, and is provided with a female pipe thread 3e in the second embodiment. The male screw 3b for assembling the inner joint body 3 is provided with an electric insulating layer 4 formed by resin coating of electrostatic powder coating of epoxy resin and heating and baking. Male thread 3b provided with an electrically insulating layer 4 by this coating
Epoxy resin adhesive 5 is applied to the inner joint body 3, and the inner joint body 3 is screwed to the assembling female screw 1b of the outer joint body 1, and the electrical insulating layer 4 and the adhesive are provided between the outer joint body 1 and the inner joint body 3. Layer 5
Therefore, it is electrically insulated. FIG. 5 shows the state of insulation coupling between the male screw 3b and the female screw 1b. Inner joint body 3 and inner resin coating layer 2 in outer joint body 1
As shown in the figure, the connecting portion with and is formed with a smooth portion and a smooth inner peripheral surface which overlap each other in the circumferential direction on the outer peripheral surface of the end portion of the inner joint main body 3 and the inner surface of the inner surface resin coating layer 2. At the time of screwing, the adhesive protruding to the side of the inner surface resin coating layer 2 adheres the smooth portion and the smooth inner peripheral surface and continuously fills and seals between the inner surface resin coating layer 2 and the inner joint body 3. Adhere and fix. For this reason, the outer joint body 1 is also shielded from the circulating water passing through it, and since it does not come into contact with the circulating water, the outer joint body does not corrode and red water does not occur. Since the inner joint body 3 is made of a copper alloy, the problem of red water does not occur even if it comes into contact with circulating water. When the inner joint body 3 is screwed, the annular ring 6 formed by the outer resin coating layer 7 is sandwiched between the end surface of the outer joint body 1 and the side surface 3d of the inner joint body 3 and protrudes toward the annular ring 6 side. The outer joint body 1, the annular ring 6, and the inner joint body 3 are integrally sealed and fixed by the adhesive 5.
Therefore, the outer joint body 1 is shielded from the external environment by the outer resin coating layer 7 that covers the entire outer surface, and is connected to the inner joint body 3 in an insulated state. Conduction between the three is also prevented. In addition, external corrosive water does not enter into the threaded joint with the outer joint body 1 and the inner joint body, and the outer joint body 1 is protected from corrosion.

[Effect of device]

As described above, in the inner and outer surface resin-coated joints of the present invention, since the outer joint body is shielded from the influence of the external moisture environment, conduction between both connecting pipes due to the influence of the external environment is prevented. Furthermore, the inner surface of the lining steel pipe is covered with the cylindrical portion of the inner surface resin coating layer, and the outer joint body is continuously covered with the inner surface resin coating layer, the adhesive layer, and the inner joint body. The joint body is also shielded from the circulating water inside to prevent corrosion. In addition, the pipe threads of the outer joint body and inner joint body that are connected to the pipe are metal screws made of the same type of material as the pipe, so the connection screw has sufficient strength, and there is no problem with the screwed connection strength. it can.

[Brief description of drawings]

FIGS. 1, 2, 3, and 4 show first, second, third, and fourth embodiments of the inner and outer surface resin-coated pipe joints of the present invention, respectively.
It is a longitudinal section showing an example. FIG. 5 is an enlarged partial cross-sectional view showing an insulating coupling state between the male screw 3b and the female screw 1b. FIG. 6 is a vertical cross-sectional view of a water insulating pipe joint showing a conventional technique. Explanation of symbols 1 ... Outer joint body, 1a ... Female thread for connecting pipe with piping 1b ... Female thread for assembly, 2 ... Inner resin coating layer 2b ... Inner surface coating part, 2c ... Cylindrical part 3 ... Inner joint body, 3a ... Piping Male thread for connecting pipe with equipment 3b… Male thread for assembly, 3c… Annular protrusion 3d… Side surface, 3e… Female thread for connecting pipe with piping 4… Electrical insulating layer, 5… Adhesive layer 6… Annular ring, 7 ... External resin coating layer

Claims (1)

[Scope of utility model registration request] 1. An outer joint body made of cast iron, which has a substantially cylindrical shape and has a female thread for a pipe connected to a resin-lined steel pipe at one end and an female thread for assembly at the other end; Has a smooth portion on the outer peripheral surface, a male thread for assembly that is screwed into the female thread for assembly of the outer joint body, and a side surface in the direction perpendicular to the axis following the male thread for assembly, and a piping device at the other end. The inner joint body made of a copper alloy of a dissimilar metal and the outer joint body having a pipe thread to be connected, the inner joint surface of the outer joint body excluding the female thread for pipe and the female thread for assembly is covered with resin and the inner side. An inner surface coating portion having a smooth inner circumferential surface that overlaps the smooth portion of the joint body in the circumferential direction, and a cylindrical portion that extends from the inner surface coating portion to the female thread side for pipe and covers the inner circumferential surface of the connecting lining steel pipe. An inner surface resin coating layer having a female thread for assembling the outer joint body and a front An electrical insulation layer having a resin coated on at least one surface of the male thread for assembling the inner joint body, a screw having the electrical insulation layer coated thereon, and a screw screwed to the screw, and an inner joint member. An adhesive layer for adhering the inner surface coating portion, and an outer surface resin coating layer coated with a resin that covers the outer surface of the outer joint body and a resin of an annular ring that covers the end surface of the outer joint body on the assembly side, wherein the outer side By screwing the joint body and the inner joint body with an adhesive layer, the annular ring of the outer resin coating layer is sandwiched between the end surface of the outer joint body and the side surface of the inner joint body and hermetically fixed by the adhesive layer. At the same time, the inner and outer surface resin-coated joints are characterized in that the inner surface of the outer joint body is continuously covered with the inner surface resin coating layer, the inner joint body, and the adhesive layer from the internal circulating water to block the inner surface.