JP6133641B2 - Insulation universal joint - Google Patents

Description

  The present invention relates to an insulating universal joint that connects a plurality of tubes so as to be rotatable about an axis under electrical insulation. More particularly, the present invention relates to an insulating universal joint that connects a gas meter inlet pipe and a gas inlet pipe in a gas meter unit such as city gas.

An example of the gas meter unit will be described with reference to FIGS.
The gas meter unit 100 suspends and supports the gas meter and incorporates a gas stopper integrally (some gas meters are mounted on top). As shown in FIG. 5, the gas meter unit 100 includes a substantially U-shaped inlet pipe (inlet trunk) 103 and outlet pipe (outlet trunk) 105, and a support plate 101 that supports them. The inlet pipe 103 and the outlet pipe 105 are respectively connected to a gas inlet pipe (gas supply pipe) 107 and an outlet pipe 109 that extend upward in a row on the back side of the support plate 101. A gas stopper handle 104 is provided on the front side of the inlet pipe 103.

  The inlet pipe 103 (made of cast iron as an example) and the inlet pipe 107 (made of cast iron as an example) are connected by an insulating universal joint 110. An example of the insulating universal joint 110 will be described with reference to FIG. The insulative universal joint 110 includes a universal nut 111 rotatably connected to the inlet pipe 103 of the gas meter unit 100, and a sleeve nut 113 that is screwed into the inlet side pipe, both of which are screwed to the screw portions 111a and 113a. Connected by. An insulating coating 120 (for example, epoxy-based powder paint) is applied to the screw portion. A collar 123 is interposed between the end surface of the universal nut 111 and the stepped portion of the sleeve nut 113 facing the end surface. In general, when there is a structure in which a member made of a dissimilar metal is in contact with the piping system, the insulating joint 110 insulates the two from each other in order to prevent electrolytic corrosion between dissimilar metals (see Patent Document 1). ).

  The universal nut 111 is rotatably connected to the inlet pipe 103 by a stop ring 137. The universal nut 111 and the inlet pipe 103 are sealed with an airtight O-ring 133 and a watertight O-ring 135. Between the two, a fireproof expansion packing 131 is further interposed. When the inlet pipe 103 becomes high temperature, it expands to seal between the two pipes.

JP 2007-2205050 A

  An object of the present invention is to provide an insulating universal joint that can further improve insulation and reduce the number of parts.

An insulating universal joint serving as a base of the present invention is an insulating universal joint that connects a plurality of pipes so as to be rotatable around an axis under electrical insulation, and has a connecting portion with the pipes, and is an outer cylinder member that fits together. And an inner cylinder member, a seal that seals the fitting portion of both the cylinder members, and a connecting member that rotatably connects the both cylinder members, and an electrically insulating coating is provided on the fitting portion of the both cylinder members. that it has been subjected to.

  According to the present invention, the joint itself can be insulated by electrically insulating coating the fitting portion of the tubular member of the joint. Thereby, the number of parts can be reduced compared with the conventional one. In general, it is economical to electrically insulate one of the outer cylinder member and the inner cylinder member. However, it is not excluded to apply an insulating coating to both cylindrical members.

  In the present invention, the electrical insulating coating is applied to an outer surface of the inner cylinder member, and the connecting member is a stop ring that is locked to an annular groove formed in a fitting portion of the both cylinder members. In addition, a resinous protective ring disposed on the inner diameter side of the stop ring may be further provided.

  A stop ring (also referred to as a retaining ring or a snap ring) is formed by forming a steel wire into a C shape, and is biased in the diameter-enlarging direction and locked in an annular groove of the inner and outer cylinder members. For this reason, when both cylinder members rotate, the end surface of the stop ring may damage the electrically insulating coating located on the outside thereof. In the present invention, since the protective ring made of resin is interposed between the stop ring and the insulating coating located on the inner side of the stop ring or further on the upper and lower sides, the stop ring does not directly contact the coating. Can prevent damage.

  In this invention, the resin-made collar arrange | positioned at the axial direction opposing part of the said both cylinder members can further be provided.

  When one of the cylindrical members is lowered by its own weight, the surface pressure of the portion facing the axial direction between both cylindrical members is increased. If the cylindrical members are rotated relative to each other in this state, the insulating coating formed on the same portion may be adversely affected such as peeling. Therefore, by disposing the collar in the facing portion, the facing surface does not come into direct contact, so that the coating can be protected.

  The gas meter suspension unit of the present invention is a gas meter suspension unit comprising an inlet pipe section and an outlet pipe section connected to a gas meter inlet and an outlet, respectively, and a support section that supports both the pipe sections. The insulating universal joint described above is arranged between the pipe portion and the gas supply pipe.

  According to the present invention, electric insulation of a gas meter can be realized without increasing the number of parts.

  As apparent from the above invention, according to the present invention, since the surface of the fitting portion of the joint with the inlet pipe of the gas meter is provided with an electrical insulation coating, the joint itself can be insulated. In addition, the number of parts can be reduced as compared with the conventional one.

It is a longitudinal cross-sectional view of the principal part of the insulated universal joint which concerns on the 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the principal part of the insulated universal joint which concerns on the 2nd Embodiment of this invention. FIG. 3 is a perspective view of a protective ring used in the insulating universal joint of FIG. 2. It is a longitudinal cross-sectional view of the principal part of the insulated universal joint which concerns on the 3rd Embodiment of this invention. It is a perspective view which shows an example of the structure (background art) of a gas meter unit. 6A is a longitudinal sectional view of the inlet pipe of the gas meter unit of FIG. 5, and FIG. 6B is a longitudinal sectional view of the main part of an example of the structure of the insulating universal joint.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
With reference to FIG. 1, the structure of the insulated universal joint which concerns on the 1st Embodiment of this invention is demonstrated.
The upper side of the insulating universal joint 1 is an outer cylinder member (also the inlet pipe 103 of the gas meter unit, see also FIG. 5). The lower side is the inner cylinder member 10 and is connected to a gas inlet pipe 107 (see FIG. 5). The inner cylinder member 10 includes a fire-resistant expansion packing 31, an airtight O-ring 33, a watertight O-ring 35, and a stop ring 37 that rotatably connects the inner cylinder member 10 to the inlet pipe 103. Is provided.

  The inner cylinder member 10 is a cylindrical member in which a gas flow passage 11 is formed in the axial center, and a fitting portion in which about half in the length direction (the upper half in the figure) is rotatably fitted in the inlet pipe 103. 15 and the other half part (the lower half of the figure) is a connection part 45 connected to the inlet side pipe. The inner cylinder member 10 is made of, for example.

  The fitting portion 15 has a shape with a tapered outer peripheral surface. More specifically, the outer peripheral surface of the fitting portion 15 has a small diameter in a stepped manner in three stages, and the first-stage small-diameter portion 16 and the second-stage small-diameter portion 17 are sequentially arranged from the connection portion 45 side toward the front side. And a third-stage small-diameter portion 18. An annular packing groove 21 into which the refractory expansion packing 31 is fitted, an annular O-ring groove 23 into which the airtight O-ring 33 is fitted, and an annular ring in which the stop ring 37 is engaged are sequentially arranged in the third stage small diameter portion 18 from the front side. The stop ring groove 27 and the annular O ring groove 25 into which the watertight O ring 35 is fitted are formed. The packing groove 21 has a shape opened to the outer peripheral surface and the end surface of the fitting portion 15.

An insulating coating 40 is formed on a part of the outer peripheral surface of the connecting portion 45 near the fitting portion 15, the outer peripheral surface of the fitting portion 15, the front end surface, and a part of the inner peripheral surface continuous from the front end surface. . On the outer peripheral surface of the fitting portion 15, insulating coating is also applied to the side surface and the back surface of each groove. The insulating coating 40 preferably has high insulating properties, low friction, and high wear resistance and rust resistance. As such an insulating coating, a fluororesin (PTFE / PTFE + MoS ₂ composite) coating (for example, Obercoat No. 208, 230, 232 (trade name), manufactured by Obercourt Co., Ltd.) can be used. The continuous use temperature range of this coating is 180 to 280 ° C. at maximum, the recommended film thickness is 5 to 20 μm, and the pencil hardness is 2 to 4H.

  The connection portion 45 is a cylindrical portion having an outer peripheral surface of the same diameter, and a screw 47 that is screwed into the inlet side pipe is formed on the inner peripheral surface.

The fireproof expansion packing 31, the airtight O-ring 33, and the watertight O-ring 35 are fitted in the packing groove 21 and the O-ring grooves 23 and 25, respectively, and the fitting portion 15 of the inner cylinder member 10 and the inlet pipe 103 of the meter unit The space between the inside is sealed.
The stop ring 37 is locked to the stop ring groove 27 and an annular groove formed in a portion of the inner surface of the inlet pipe 103 facing the groove 27, so that the inner cylinder member 10 and the inlet pipe 103 are rotatably connected. doing.

In the present invention, the conventional nut 111, sleeve nut 113, and collar 123 described in FIG. 6 are used as one component (inner cylinder member 10), and the inner cylinder member 10 is connected to the inlet pipe 103 of the gas meter unit. Since the contact portion (fitting portion 15) is insulated, the number of parts can be reduced.
Insulating coating of the inner surface of the inlet pipe 103 of the gas meter unit with the fitting portion 15 of the inner cylinder member 10 is not preferable because the end surface of the stop ring 37 is easily rubbed with the coating. The stop ring 37 is formed by forming a steel wire into a C-shape, and is biased in the diameter-expanding direction. For this reason, the end surface of the stop ring 37 may rub against the coating on the outer diameter side due to the rotation of the fitting portion 15, and the coating may be damaged. Therefore, it is preferable to apply an insulating coating to the inner diameter side fitting portion 15 where the stop ring 37 does not contact. Moreover, it is preferable to apply to the surface of a member also from the point of coating workability | operativity.

  With reference to FIG. 2, the structure of the insulated universal joint which concerns on the 2nd Embodiment of this invention is demonstrated. In this example, a protective ring 50 for protecting the stop ring 37 is added to the joint of the first embodiment described in FIG. Members / parts having the same configuration / action as the joint of FIG. 1 are denoted by the same reference numerals as those in FIG.

  The joint 1A of this example includes a protective ring 50 into which the stop ring 37 is fitted. As shown in FIG. 3, the protective ring 50 is C-shaped in plan as in the case of the stop ring 37, and a C-shaped groove 50a whose cross-sectional shape opens outward is formed on the entire circumference of the outer peripheral surface. ing. A stop ring 37 is fitted into the C-shaped groove 50a. In this state, as shown in FIG. 2, the protection ring 50 covers the outer peripheral surface on the inner diameter side and the upper and lower sides of the stop ring 37, and only the outer diameter side surface is exposed from the protection ring 50. The protective ring 50 is made of an insulating resin (for example, made of polyester). When mounting on the inner cylinder member 10, first, the stop ring 37 is fitted into the groove 50 a of the protective ring 50, and then mounted on the stop ring groove 27 of the fitting portion 15.

  As described above, the stop ring 37 is a C-shaped member, and is biased in the diameter increasing direction, so that the end surface comes into contact with a surface located on the outer diameter side or the upper and lower sides of the stop ring 37. For this reason, there is a possibility that the end surface of the stop ring 37 is rubbed with the coating located on the outer diameter side or the upper and lower sides due to the rotation of the fitting portion 15 and the coating is damaged. Therefore, when the protective ring 50 as shown in FIG. 3 is provided, the protective ring 50 is interposed between the upper and lower surfaces of the groove 27 in which the stop ring 37 and the insulating coating 40 are formed. . Therefore, these coatings 40 can be protected.

  With reference to FIG. 4, the structure of the insulated universal joint which concerns on the 3rd Embodiment of this invention is demonstrated. In this example, a collar is added to the joint of the first embodiment described in FIG. Members / parts having the same configuration / action as the joint of FIG. 2 are assigned the same reference numerals as in FIG.

  In the joint 1 </ b> B, a collar is disposed between the portions where the fitting portion 15 of the inner cylinder member 10 and the inlet pipe 103 of the gas meter unit face each other in the axial direction. For example, the collar 61 can be disposed between the upper end surface of the fitting portion 15 and the inner end surface of the inlet pipe 103. Alternatively, the collar 63 can be disposed between the end surface of the first-stage small-diameter portion 16 of the fitting portion 15 and the second-stage inner end surface of the inlet pipe 103. Alternatively, the collar 65 can be disposed between the end surface between the first-stage small-diameter portion 16 and the connection portion 45 and the outer end surface of the inlet pipe 103. The color is made of resin (for example, made of polyester).

  When the inlet pipe 103 of the gas meter unit is lowered by its own weight, the surface pressure of the portion of the inner cylinder member 10 facing the inlet pipe 103 in the axial direction increases. Thereby, there exists a possibility that the insulating coating 40 may receive bad influences, such as peeling. Therefore, when a collar is disposed in any part of the inner cylinder member 10 facing the inlet pipe 103 in the axial direction, the clearance between the inlet pipe 103 and the fitting portion 15 in the axial direction is increased by the thickness of the collar. Therefore, since the end surface of the inlet pipe 103 does not directly contact the insulating coating 40, the coating 40 can be protected.

  The insulated universal joint of the present invention can be used to connect the inlet pipe 103 and the inlet pipe 107 of the gas meter unit shown in FIG. In this case, both can be insulated and connected without increasing the number of parts compared to a conventional joint.

DESCRIPTION OF SYMBOLS 1 Insulation universal joint 10 Inner cylinder member 11 Gas flow path 15 Fitting part 16 First stage small diameter part 17 Second stage small diameter part 18 Third stage small diameter part 21 Packing groove 23, 25 O-ring groove 27 Stop ring groove 31 Fireproof expansion packing 33 Airtight O-ring 35 Watertight O-ring 37 Stop ring 40 Electrical insulation coating 45 Connection 47 Screw 50 Protective ring 61, 63, 65 Color 103 Inlet

Claims (5)

An insulative universal joint that connects a plurality of tubes so as to be rotatable about an axis under electrical insulation,
An outer cylinder member and an inner cylinder member that have a connecting portion with the pipe and fit to each other;
A seal that seals the fitting portion of both cylindrical members;
A connecting member for rotatably connecting both cylindrical members,
Electrical insulation coating is applied to the fitting part of both the cylindrical members ,
The electrical insulation coating is applied to the outer surface of the inner cylinder member;
The connecting member is a stop ring that is locked to an annular groove formed on the outer surface of the inner cylinder member,
Further comprising a protective ring made of resin disposed on the inner diameter side of the stop ring,
In the protective ring, a groove having a cross-sectional shape opened to the outside and into which the stop ring is fitted is formed on the outer peripheral surface,
The protective ring covers the inner diameter side and upper and lower surfaces of the stop ring to prevent direct contact between the stop ring and the upper and lower surfaces of the annular groove on which the insulating coating is formed. Characteristic insulation universal joint. The inner cylinder member is formed with a groove into which the seal is fitted and a groove into which the connecting member is fitted,
The insulating universal joint according to claim 1, wherein the electrically insulating coating is applied to an outer surface of the inner cylinder member including a side surface and a back surface of the groove. 3. The insulating universal joint according to claim 1, wherein the electrically insulating coating is made of a low friction resin. A plurality of axially opposed portions consisting of end faces or step portions facing in the axial direction are formed in the fitting portions of both the cylindrical members,
  A resin collar is disposed at one of the plurality of axially opposed portions,
  A gap is opened in the axially facing portion other than the one axially facing portion,
  The direct contact of the said end surface or step part of the said both cylindrical members is prevented by this, and the coating applied to the said end surface or step part is protected, The Claim 1, 2, or 3 characterized by the above-mentioned. Insulation universal joint. A gas meter suspension unit comprising an inlet pipe part and an outlet pipe part connected to the gas meter inlet and outlet, respectively, and a support part for supporting both the pipe parts,
A gas meter suspension unit, wherein the insulating universal joint according to any one of claims 1 to 4 is disposed between the inlet pipe portion and the gas supply pipe.

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