JPH074386Y2 - Electrically insulated pipe fittings for water - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to an electrically insulating pipe joint mainly used for connecting an inner resin lined steel pipe used for water pipes and a copper alloy pipe component.

[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. Sho 63-129785. As shown in FIG. 6, this is a cast iron joint main body 70 having a substantially cylindrical shape and having a female thread 71 for pipe on the inner peripheral surface of one end and a female thread 72 on the inner peripheral surface of the other end, except for the female thread 71 for pipe. A resin coating portion 80 lined on the inner peripheral surface is formed, and a female thread 81 for a pipe formed by the resin coating portion 80 is provided on the inner peripheral surface coated with the female thread 72, and a gap is formed between the female thread 71 for the pipe and the female thread 71 for the pipe. Thus, the cylindrical portion 83 made of the resin coating portion 80 is integrally formed.
Then, the internal thread 81 for the pipe and the internal thread 81 for the pipe are formed by the internal thread 81 for the internal surface resin coating portion 80 provided on the inner surface of the joint body 70.
It is designed to insulate between the pipes connected to.

[Problems to be solved by the device]

However, in the above-mentioned conventional pipe joint, the female thread 81 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 81 was destroyed and could not be connected, or leakage occurred at this connection part. Therefore, the present invention achieves insulation between dissimilar metal pipes such as the inner surface resin-lined steel pipe and copper alloy pipe parts, etc. to prevent corrosion due to contact with dissimilar metals and to block corrosion from internal fluids as well as to prevent pipe connection. An electrically insulating pipe joint for water pipes that can be connected without any problem.

[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 covering portion, and an annular ring of an electrically insulating material sandwiched between the female thread side end surface for assembly of the outer joint body and the side surface of the inner joint body, By screwing and coupling the outer joint body and the inner joint body with an adhesive layer, the annular ring 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. An electrically insulating pipe joint for water, characterized in that the inner surface of the outer joint body is continuously covered and shielded from the internal circulating water by the inner surface resin coating layer, the inner joint body and the adhesive layer.

[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. Further, since the annular ring of the electrically insulating material is sandwiched between the assembly side end surface of the outer joint body and the side surface of the inner joint body and hermetically fixed with the adhesive, the threaded joint portion of the inner and outer joint body is connected to the outside. Shields from corrosive environments and maintains insulation. 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.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of an electrically insulating pipe joint for water showing a first embodiment of the present invention, and FIGS. 3 to 5 show second to fourth embodiments, respectively, which will be described according to the manufacturing procedure. To do. Reference numeral 10 denotes an outer joint body, which is a malleable cast iron screw-in 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 10, a cylindrical portion 23 that covers the inner surface of the lining steel pipe connected to the pipe and the female thread 11 for pipe connection, and this cylindrical portion 23. An inner surface resin coating layer (20) integrally having an inner surface (22) for pipes on both sides and an inner surface covering portion (22) for covering the inner surface of the central part excluding the assembling screw (12) is provided. Reference numeral 30 denotes an inner joint body made of a copper alloy, a smooth portion on the outer surface of the end portion on the assembling side, an assembling male thread 32 to be engaged with the assembling female thread 12 of the outer joint body 10, and subsequently, a direction perpendicular to the axis. Has a side surface 331 and the other end is provided with a pipe screw for connection with a copper alloy pipe fitting. This pipe screw is provided with a pipe male thread 31 in the first, third and fourth embodiments and is provided with a pipe female screw 34 in the second embodiment.
Is provided. The male screw 32 for assembling the inner joint body 30 is provided with an electric insulating layer 40 by resin coating in which an epoxy resin is electrostatically powder coated and baked. An annular ring 6 made of an electrically insulating material is provided on the side surface 331 of the inner joint main body 30 provided with the electrically insulating layer 40 by this coating.
Install 0, apply epoxy resin adhesive to the male thread 32 for assembly, and screw it to the female thread 12 for assembly of the outer joint body 10, and electrically insulate between the outer joint body 10 and the inner joint body 30. Are joined by. The state of this insulating coupling portion is shown in FIG. The joint portion between the inner joint body 30 and the resin coating layer 20 in the outer joint body 10 is a smooth portion that overlaps with the outer peripheral surface of the end portion of the inner joint body 30 and the inner surface of the resin coating layer 20 in the circumferential direction as illustrated. A smooth inner peripheral surface is formed, and when the inner joint body 30 is screwed, the adhesive protruding to the resin coating layer 20 side adheres the smooth portion and the smooth inner peripheral surface, and the resin coating layer 20 and the inner joint. The space between the main body 3 and the main body 3 is continuously filled, sealed, and adhesively fixed. Therefore, the outer joint body 10 is also blocked from the circulating water passing through the inside, and since it does not come into contact with the circulating water, the outer joint body 10 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. Further, when the inner joint body 30 is screwed, the annular ring 60 formed of an electrically insulating material is sandwiched between the end surface of the outer joint body 10 and the side surface 331 of the inner joint body 30 and protrudes toward the annular ring 60 side. The outer joint body 10, the annular ring 60, and the inner joint body 30 are integrally sealed and fixed by the adhesive 50. Therefore, the outer joint body 10 and the inner joint body 30 are coupled in an insulated state, and the insulating joint portion with the inner and outer joint body is shielded from the external environment by sandwiching the annular ring 60, so that external corrosive water, etc. Does not enter the insulation coupling part, and long-term insulation performance is maintained.

[Effect of device]

As described above, in the electrical insulation pipe joint for water of the present invention, the inner surface of the connected lining steel pipe is covered with the cylindrical portion of the inner surface resin coating layer, and the outer joint body includes the inner surface resin coating layer, the adhesive layer and the inner joint body. Since it is continuously covered with, the end surface of the connection lining steel pipe and the inner surface of the outer joint body are also shielded from the circulating water in the interior to be protected from corrosion. Further, since the insulating screw-bonded portion is shielded from the external moisture environment by sandwiching the annular ring, external corrosive water or the like does not enter the insulating joint portion, and long-term insulating performance is maintained. 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]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the electrical insulation pipe joint for water of the present invention. FIG. 2 is an enlarged sectional view of the threaded portion of the male screw 32 and the female screw 12 of FIG. 3, 4, and 5 are longitudinal sectional views showing second, third, and fourth embodiments of the electrically insulating pipe joint for water of the present invention, respectively. FIG. 6 is a vertical cross-sectional view of a water insulating pipe joint showing a conventional technique. Explanation of symbols 10 ... Outer joint body, 11 ... Female thread for connecting pipe with pipe 12 ... Female thread for assembly, 20 ... Inner surface resin coating layer 22 ... Inner surface coating part, 23 ... Cylindrical part 30 ... Inner fitting body, 31 ... Piping Male thread for pipes for connection to equipment 32… Male thread for assembly, 33… Annular protrusion 331… Side surface, 34… Female thread for connection with pipe 40… Electrical insulation layer, 50… Adhesive layer 60… Annular ring

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 annular ring of an electrically insulating material sandwiched between the female thread side end surface for assembly of the outer joint body and the side surface of the inner joint body, By screwing the outer joint body and the inner joint body with an adhesive layer, the annular ring 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, An electrically insulating pipe joint for water, characterized in that the inner surface of the outer joint body is continuously covered and blocked from the internal circulating water by the inner surface resin coating layer, the inner joint body and the adhesive layer.