JPH01221679A - Resistance measuring method for insulation coupling - Google Patents
Resistance measuring method for insulation couplingInfo
- Publication number
- JPH01221679A JPH01221679A JP4799888A JP4799888A JPH01221679A JP H01221679 A JPH01221679 A JP H01221679A JP 4799888 A JP4799888 A JP 4799888A JP 4799888 A JP4799888 A JP 4799888A JP H01221679 A JPH01221679 A JP H01221679A
- Authority
- JP
- Japan
- Prior art keywords
- resistance
- pipe
- joint
- insulation
- piping
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 12
- 238000009413 insulation Methods 0.000 title abstract description 22
- 230000008878 coupling Effects 0.000 title abstract 9
- 238000010168 coupling process Methods 0.000 title abstract 9
- 238000005859 coupling reaction Methods 0.000 title abstract 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 8
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000010276 construction Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005536 corrosion prevention Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 239000012784 inorganic fiber Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 210000002445 nipple Anatomy 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
- Flanged Joints, Insulating Joints, And Other Joints (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、配管系において絶縁継手の抵抗を測定する
方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a method for measuring the resistance of an insulating joint in a piping system.
ガス配管や水用配管等を施工する場合、迷走電流等によ
る配管の腐蝕を防止するためにはその配管系の途中の個
所を絶縁しておくことが有効であり、その絶縁個所には
鋼管同士の接続個所が選定されることが多い。そこで従
来より、継手自体が絶縁部を具備している絶縁継手を用
いて鋼管同士を接続し、所定の配管系を施工することが
ある。When constructing gas piping, water piping, etc., it is effective to insulate the middle of the piping system in order to prevent corrosion of the piping due to stray current, etc. Connection points are often selected. Therefore, conventionally, steel pipes are connected to each other using an insulating joint in which the joint itself has an insulating part, and a predetermined piping system is constructed.
このような配管系に介在される絶縁継手としては実開昭
６０−６１５８４号公報に開示されたものがある。An example of an insulating joint interposed in such a piping system is disclosed in Japanese Utility Model Application Publication No. 60-61584.
このものは第５図に示すように筒状の継手本体が二つの
筒体１１０．１２０に分割され、一方の筒体１１０に突
設したボス１１１の外面を絶縁層１１２で覆わせ、この
絶縁層１１２を介してボス１１１を他方の筒体１２０に
ねじ込んで双方の筒体１１０．１２０を一体に連結した
ものである。このような絶縁継手を用いた配管系では、
一方の筒体１１０の接続口１１３にねじ込まれる鋼管と
他方の筒体１２０の接続口１２３にねじ込まれる鋼管と
が双方の筒体１１０，１２０の接続個所である一僧所で
絶縁層１１２により電気的に絶縁された状態で接続され
る。As shown in FIG. 5, the cylindrical joint body is divided into two cylindrical bodies 110 and 120, and the outer surface of a boss 111 protruding from one cylindrical body 110 is covered with an insulating layer 112. The boss 111 is screwed into the other cylindrical body 120 via the layer 112 to connect both cylindrical bodies 110 and 120 together. In piping systems using such insulated joints,
The steel pipe screwed into the connection port 113 of one cylindrical body 110 and the steel pipe screwed into the connection port 123 of the other cylindrical body 120 are electrically connected to each other by an insulating layer 112 at the connection point of both cylindrical bodies 110 and 120. connected in an isolated state.
ところで、鋼管及び絶縁継手を用いたガス配管や水用配
管等の配管系にあっては、配管の電蝕防止効果を確認す
ることなどを主眼として、絶縁継手とその片側の管体と
に抵抗測定器の電極を接続して絶縁継手の抵抗を測定す
ることがある。By the way, in piping systems such as gas piping and water piping that use steel pipes and insulated joints, resistance is applied to the insulated joint and the pipe on one side, mainly to check the effectiveness of preventing galvanic corrosion of the piping. The resistance of an insulated joint may be measured by connecting the electrodes of a measuring device.
例えば第６図に示した配管系モデルのように地中に埋設
された主管又は支管（以下、支管という。For example, as shown in the piping system model shown in Fig. 6, a main pipe or a branch pipe (hereinafter referred to as a branch pipe) is buried underground.
）１３０から分岐された引込み管１３１の始端部１３２
と中間部１３３が地中に埋設され、上記引込み管１３１
に絶縁継手Ａを介して屋内配管１３４が接続されている
配管系において絶縁継手Ａの抵抗を測定する場合には、
絶縁継手Ａと引込み管１３１又は屋内配管１３４とに抵
抗測定器の電極を接続する。) 130 and the starting end 132 of the lead-in pipe 131
and an intermediate portion 133 are buried underground, and the above-mentioned lead-in pipe 131
When measuring the resistance of the insulated joint A in a piping system in which the indoor piping 134 is connected to the insulated joint A through the insulated joint A,
Connect the electrode of the resistance measuring device to the insulated joint A and the lead-in pipe 131 or the indoor piping 134.
ところが、従来の抵抗測定方法によると、上述したよう
に絶縁継手Ａの一個所でのみ引込み管１３１と屋内配管
１３４が絶縁されているに過ぎないため、例えば第６図
のように地中に埋設された水道管１４０の立上り部１４
１が屋内配管１３４に接触しているような場合（接触個
所をイで示す。However, according to the conventional resistance measurement method, as mentioned above, the service pipe 131 and the indoor pipe 134 are insulated only at one location of the insulating joint A. Rising part 14 of water pipe 140
1 is in contact with indoor piping 134 (the contact point is indicated by A).
）には、実測抵抗値Ｒが引込み管１３１の接地抵抗Ｒ３
や支管１３０の接地抵抗Ｒ４や水道管１４０の接地抵抗
Ｒ２の影響を受けた合成抵抗になる。そのため、従来の
測定方法では、配管施工後の電蝕防止効果の確認検査等
において絶縁継手の真の抵抗Ｐ、を正確に測定すること
ができないという問題があった。), the measured resistance value R is the grounding resistance R3 of the lead-in pipe 131.
It becomes a composite resistance influenced by the grounding resistance R4 of the branch pipe 130 and the grounding resistance R2 of the water pipe 140. Therefore, with the conventional measuring method, there was a problem in that the true resistance P of the insulating joint could not be accurately measured in tests to confirm the galvanic corrosion prevention effect after piping construction.
さらに、抵抗測定回路を形成する場合には、絶縁継手Ａ
の絶縁層１１２を挾む状態で絶縁継手Ａと引込み管１３
１又は屋内配管１３４とに抵抗測定器の電極を接続する
ことが必要であるため、絶縁継手Ａの特定の個所でしか
抵抗を測定することができないという問題もあった。Furthermore, when forming a resistance measurement circuit, insulated joint A
The insulating joint A and the lead-in pipe 13 are sandwiched between the insulating layer 112 of
Since it is necessary to connect the electrode of the resistance measuring device to 1 or the indoor piping 134, there is also a problem that the resistance can only be measured at a specific location of the insulated joint A.
この発明は以上の問題に鑑みてなされたもので、絶縁継
手の二個所を絶縁した状態で抵抗を測定することによっ
て、配管系の管体が接地されていたりその配管系に別の
配管系や鉄筋等が接触していたりしていても、配管施工
後に絶縁継手の真の抵抗を正確に測定することが可能で
あり、しかも絶縁継手に対する結線個所が特定の個所に
限定されない絶縁継手の抵抗測定方法を提供することを
目的とする。This invention was made in view of the above problem, and by measuring the resistance with the two parts of the insulated joint insulated, it is possible to detect whether the pipe body of the piping system is grounded or if the piping system is connected to another piping system. It is possible to accurately measure the true resistance of insulated joints after piping construction, even if they are in contact with reinforcing bars, etc., and the resistance measurement of insulated joints does not limit the connection points to specific points. The purpose is to provide a method.
この発明による絶縁継手の抵抗測定方法は、絶８！継手
の二つの接続口のそれぞれに絶縁層を具備させてこの絶
縁継手とそれぞれの接続口に接続された管体とを絶縁し
ておき、抵抗測定器の一方の電極を絶縁継手の表面に、
他方の電極を絶縁継手の片側の管体の表面に接続するも
のである。The method for measuring the resistance of insulated joints according to this invention is absolutely 8! An insulating layer is provided on each of the two connection ports of the joint to insulate the pipe body connected to each connection port, and one electrode of the resistance measuring device is placed on the surface of the insulated joint.
The other electrode is connected to the surface of the tube on one side of the insulated joint.
この発明による絶縁継手の抵抗測定方法によれば、絶縁
継手の二つの接続口のそれぞれに具備された絶縁層のう
ち、抵抗測定回路に含まれない側の絶縁層によって配管
系の管体の接地抵抗や別の配管系の接地抵抗や土壌間抵
抗の影響が断ち切られるため、測定された絶縁継手の抵
抗値にはそれらの影響が及ばない。According to the method for measuring the resistance of an insulated joint according to the present invention, of the insulating layers provided at each of the two connection ports of the insulated joint, the insulating layer on the side that is not included in the resistance measurement circuit is used to ground the pipe body of the piping system. Since the influence of the resistance, the ground resistance of another piping system, and the soil resistance is cut off, the measured resistance value of the insulated joint is not influenced by them.
第１図はこの発明による絶縁継手の抵抗測定方法が実施
される配管系モデルの一例を示す配管図で、絶縁継手Ａ
の構成を除く他の構成は第６図で説明した配管系モデル
と同様である。従って同一部分には同一符号を付して詳
細な説明を省略する。FIG. 1 is a piping diagram showing an example of a piping system model in which the method for measuring the resistance of an insulated joint according to the present invention is implemented.
The other configurations except for the configuration are the same as the piping system model explained in FIG. Therefore, the same parts are given the same reference numerals and detailed explanations will be omitted.
この発明の詳細な説明する前に上記配管系モデルに使用
される絶縁継手Ａの具体的構成例を説明する。第３図は
ソケット型の絶縁継手Ａを例示したものである。１は管
継手本体で、その両端に具備されたそれぞれの接続口２
．３の内面にはテーパ状のめねじよりなる管螺合用ねじ
部４，５が形成されており、これらの管螺合用ねじ部４
．５がそれぞれ別々の絶縁層６．７によって覆われてい
る。管螺合用ねじ部４の内径及び谷径はそれぞれ管螺合
に適する標準ねじの内径及び谷径よりもや−大きくなっ
ており、その大きめの内径及び谷径がそれぞれ絶縁層６
の厚みによって標準ねじの内径及び谷径と同等になるよ
うに補正されている。Before explaining the present invention in detail, a specific example of the configuration of the insulating joint A used in the piping system model will be explained. FIG. 3 shows an example of a socket-type insulating joint A. 1 is a pipe joint body, and each connection port 2 is provided at both ends of the pipe joint body.
．． Pipe threaded parts 4 and 5 made of tapered internal threads are formed on the inner surface of 3.
．． 5 are each covered by a separate insulating layer 6.7. The inner diameter and root diameter of the pipe threaded portion 4 are respectively slightly larger than the inner diameter and root diameter of a standard screw suitable for pipe screwing, and the larger inner diameter and root diameter are the same as those of the insulating layer 6.
The thickness has been corrected to be equivalent to the inner diameter and root diameter of a standard screw.
そして火災等で絶縁層６が消失しても管端が容易に引き
抜かれないように絶縁層の厚みが設計されている。他端
側の管螺合用ねじ部５についても同様の構成である。絶
縁層６．７にはガラス繊維等の無機質繊維をエポキシ系
、フェノール系、ポリエステル系等の合成樹脂と混ぜた
ＦＲＰやプリプレグ処理クロス等を好適に用いることが
でき、これらを絶縁層６，７とした絶縁性管継手Ａにあ
っては、火災時において絶縁層６．７の燃焼により生成
する炭化物等によってガス漏れが未然に防止される利点
がある。The thickness of the insulating layer is designed so that even if the insulating layer 6 is lost due to a fire or the like, the tube end will not be easily pulled out. The pipe threaded portion 5 on the other end side has a similar configuration. For the insulating layers 6.7, FRP or prepreg treated cloth, which is a mixture of inorganic fibers such as glass fibers with synthetic resins such as epoxy, phenol, and polyester, can be suitably used. The insulating pipe joint A has the advantage that gas leakage can be prevented by carbide, etc. generated by combustion of the insulating layer 6, 7 in the event of a fire.
第４図はニップル型の絶Ｉ！継手Ａを例示している。同
図の絶縁継手Ａの管継手本体１は鍔部８を備え、この鍔
部８の両側に接続口２．３が突設されており、これらの
接続口２．３の外面にテーパ状のおねじよりなる管螺合
用ねじ部４，５が具備され、これらの管螺合用ねじ部４
，５が絶縁層６゜７によって覆われてなる。管螺合用ね
じ部６，７のねじ径（内径及び谷径）が絶縁層６．７に
よって管螺合に適する標準ねじ径に補正されている点は
第３図の絶縁継手Ａと同様である。Figure 4 is the perfect nipple type! Joint A is illustrated. The pipe joint body 1 of the insulating joint A in the same figure is equipped with a flange 8, and connection ports 2.3 are protruded from both sides of the flange 8, and tapered grooves are formed on the outer surface of these connection ports 2.3. Pipe threaded parts 4 and 5 made of external threads are provided, and these threaded parts 4 for pipe threaded threading are provided.
, 5 are covered with an insulating layer 6.7. It is similar to the insulated joint A in Fig. 3 in that the thread diameter (inner diameter and root diameter) of the threaded parts 6 and 7 for pipe threading is corrected to a standard thread diameter suitable for pipe threading by the insulating layer 6.7. .
以上説明した二種類の絶縁継手Ａにおいて、管１０．２
０を接続した場合には、絶縁継手Ａと管１０．２０のそ
れぞれが絶縁層６，７によって電気的に絶縁された状態
となる。In the two types of insulation joints A explained above, the pipe 10.2
0 is connected, the insulating joint A and the tube 10.20 are electrically insulated by the insulating layers 6 and 7, respectively.
絶縁継手Ａの抵抗を測定するには、図示していない抵抗
測定器の一方の電極を絶！！継手Ａの表面に接続し、他
方の電極を絶８！継手Ａの片側の管体例えば引込み管１
３１の表面に接続して所定の電圧を印加する。こうして
測定される実測抵抗Ｒは、絶縁継手Ａの絶縁Ｎ５ （第
３・４図参照）が具備している真の抵抗Ｒ５である。即
ち、支管１３０の接地抵抗Ｒ４や引込み管１３１の接地
抵抗Ｒ３や屋内配管１３４に接触している水道管１４１
の接地抵抗Ｒ２の影響が絶縁層４（第３・４図参照）に
よって断ち切られ、それらの影響が実測抵抗Ｒに及ばな
いからである。同様に、絶縁継手Ａの表面と屋内配管１
３４の表面とに電圧を印加して測定した実測抵抗Ｒ°は
、絶縁継手Ａの絶縁層４（第３・４図参照）が具備して
いる真の抵抗し°である。To measure the resistance of insulated joint A, disconnect one electrode of the resistance measuring device (not shown)! ! Connect to the surface of joint A and disconnect the other electrode! Pipe body on one side of joint A, for example, lead-in pipe 1
31 and apply a predetermined voltage. The measured resistance R thus measured is the true resistance R5 of the insulation N5 of the insulating joint A (see Figures 3 and 4). That is, the ground resistance R4 of the branch pipe 130, the ground resistance R3 of the lead-in pipe 131, and the water pipe 141 in contact with the indoor pipe 134.
This is because the influence of the ground resistance R2 is cut off by the insulating layer 4 (see FIGS. 3 and 4), and these influences do not affect the actually measured resistance R. Similarly, the surface of insulation joint A and indoor piping 1
The actual resistance R° measured by applying a voltage to the surface of the insulating joint A is the true resistance of the insulating layer 4 of the insulating joint A (see FIGS. 3 and 4).
支管１３０の接地抵抗Ｒ４や引込み管１３１の接地抵抗
Ｒ１や水道管１４１の接地抵抗Ｒ２の影響が絶縁層５（
第３・４図参照）によって断ち切られ、それらの影響が
実測抵抗Ｒ°に及ばないからである。The influence of the grounding resistance R4 of the branch pipe 130, the grounding resistance R1 of the lead-in pipe 131, and the grounding resistance R2 of the water pipe 141 affects the insulation layer 5 (
(see Figures 3 and 4), and their influence does not affect the actually measured resistance R°.
このように絶縁継手Ａの真の抵抗Ｒ１＋ Ｒ１′が実測
されることを利用すれば、施工後の配管系が別の配管系
に接触しているか否かを判別することも容易に可能であ
る。次に、その判別手段を説明する。第２図は上記判別
を行う場合の抵抗測定回路を表したものである。By utilizing the fact that the true resistance R1 + R1' of the insulated joint A is actually measured in this way, it is also possible to easily determine whether or not the piping system after construction is in contact with another piping system. . Next, the determining means will be explained. FIG. 2 shows a resistance measuring circuit for performing the above discrimination.
この場合には例えば絶縁継手Ａの両側の引込み管１３１
と屋内配管１３４のそれぞれの表面に電圧を印加するこ
とにより抵抗を実測（実測抵抗Ｒ″）することと、絶縁
継手Ａの表面と引込み管１３１の表面とに電圧を印加し
て抵抗を実測（実測抵抗Ｒ）することと、絶縁継手Ａの
表面と屋内配管１３４の表面とに電圧を印加して抵抗を
実測すること（実測抵抗Ｒ’）とを行う。なお、同図の
抵抗測定回路において、Ｒ３が上述したＲＺ、 Ｒ３＋
Ｒ４による全体の抵抗を表している。即ち、である。In this case, for example, the lead-in pipes 131 on both sides of the insulating joint A
The resistance is actually measured (actually measured resistance R'') by applying a voltage to each surface of the and indoor piping 134, and the resistance is actually measured by applying a voltage to the surface of the insulated joint A and the surface of the lead-in pipe 131 ( Actual resistance R) is applied to the surface of the insulating joint A and the surface of the indoor piping 134 to measure the resistance (actual resistance R'). , R3 is RZ mentioned above, R3+
It represents the overall resistance due to R4. That is,.
上述した三種類の抵抗を測定した結果、ＲＩｔとＲ（又
はＲ’）との値が異なる場合には、配管系同士が接触し
ていることなどが原因で抵抗値が低下していることが判
る。As a result of measuring the three types of resistance mentioned above, if the values of RIt and R (or R') are different, it is likely that the resistance value has decreased due to reasons such as contact between the piping systems. I understand.
数表に実際の測定結果を例示する。The actual measurement results are illustrated in the numerical table.
この発明による絶縁継手の抵抗測定方法によれば、配管
施工後において、配管系に別の配管系や鉄筋等が接触し
ている場合であっても別の配管系等の接地抵抗や双方の
配管系等の相互間に生じる土壌間抵抗の影響を受けない
絶縁継手の真の抵抗を測定することが可能になるという
効果がある。According to the method for measuring the resistance of an insulated joint according to the present invention, even if the piping system is in contact with another piping system, reinforcing bars, etc. after piping construction, the ground resistance of the other piping system, etc. This method has the effect of making it possible to measure the true resistance of an insulated joint that is not affected by soil resistance that occurs between systems.
さらにこの発明によると結線個所が絶縁継手の特定の個
所に限定されないという効果もある。Further, according to the present invention, there is an effect that the connection point is not limited to a specific point of the insulating joint.
第１図はこの発明による絶縁継手の抵抗測定方法を実施
するための配管系モデルの一例を示す配管図、第２図は
第１図の配管系モデルに対応する回路を表した回路図、
第３図は上記配管系モデルに使用されている絶縁継手の
一例を示す断面図、第４図は上記配管系モデルに使用さ
れている絶縁継手の他の例を示す断面図、第５図は従来
の配管系に使用されていた絶縁継手の一例を示す部分断
面図、第６図は従来の絶縁継手の抵抗測定方法を実施す
るための配管系モデルの一桝を示す配管図である。
Ａ・・・絶縁継手、２．３・・・接続口、６，７・・・
絶縁層、１０．２０・・・管体、１３１・・・引込み管
、１３４・・・屋内配管。FIG. 1 is a piping diagram showing an example of a piping system model for carrying out the method for measuring resistance of an insulated joint according to the present invention, and FIG. 2 is a circuit diagram showing a circuit corresponding to the piping system model of FIG. 1.
Figure 3 is a sectional view showing an example of the insulation joint used in the piping system model, Figure 4 is a sectional view showing another example of the insulation joint used in the piping system model, and Figure 5 is a sectional view showing another example of the insulation joint used in the piping system model. FIG. 6 is a partial cross-sectional view showing an example of an insulated joint used in a conventional piping system, and FIG. 6 is a piping diagram showing one section of a piping system model for carrying out the conventional method for measuring the resistance of an insulated joint. A...Insulation joint, 2.3...Connection port, 6,7...
Insulating layer, 10.20... Pipe body, 131... Leading pipe, 134... Indoor piping.
Claims (1)
に各別の管体が接続されている配管系において上記絶縁
継手の抵抗を測定する方法であって、 上記絶縁継手の二つの接続口のそれぞれに絶縁層を具備
させてこの絶縁継手とそれぞれの接続口に接続された管
体とを絶縁しておき、抵抗検出器の一方の電極を上記絶
縁継手の表面に、他方の電極を上記絶縁継手の片側の管
体の表面に接続することを特徴とする絶縁継手の抵抗測
定方法。[Claims] 1. A method for measuring the resistance of the insulating joint in a piping system in which separate pipe bodies are connected to each of two connection ports provided in the insulating joint, comprising: An insulating layer is provided on each of the two connection ports of the joint to insulate the pipe body connected to each connection port, and one electrode of the resistance detector is placed on the surface of the insulated joint. . A method for measuring resistance of an insulated joint, characterized in that the other electrode is connected to the surface of a tube on one side of the insulated joint.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4799888A JPH01221679A (en) | 1988-02-29 | 1988-02-29 | Resistance measuring method for insulation coupling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4799888A JPH01221679A (en) | 1988-02-29 | 1988-02-29 | Resistance measuring method for insulation coupling |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01221679A true JPH01221679A (en) | 1989-09-05 |
Family
ID=12790988
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4799888A Pending JPH01221679A (en) | 1988-02-29 | 1988-02-29 | Resistance measuring method for insulation coupling |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01221679A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7235268B1 (en) * | 2023-01-17 | 2023-03-08 | 日本リニューアル株式会社 | How to rehabilitate water supply pipes |
| JP7244891B1 (en) * | 2023-01-17 | 2023-03-23 | 日本リニューアル株式会社 | insulated threaded pipe fittings |
-
1988
- 1988-02-29 JP JP4799888A patent/JPH01221679A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7235268B1 (en) * | 2023-01-17 | 2023-03-08 | 日本リニューアル株式会社 | How to rehabilitate water supply pipes |
| JP7244891B1 (en) * | 2023-01-17 | 2023-03-23 | 日本リニューアル株式会社 | insulated threaded pipe fittings |
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