JP2907375B2 - Dust proof ring for conduit air cable connection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust-proof ring for connecting a cable to a pipe in the air, which is excellent in dust-proof property.

[0002]

2. Description of the Related Art A pipe air cable has an aluminum conductor disposed in the center of a pipe and an insulating gas (SF ₆ ) press-fitted inside the pipe. Since this cable has a high dielectric strength and good heat dissipation, the diameter of the conduit can be reduced and the transmission capacity can be increased. Since this cable is rigid and cannot be wound, the unit length of the factory manufacturing is as short as about 10 to 14 m. Therefore, it is laid by welding on site.

As shown in FIG. 2, in the welding of the conduit air cable, as shown in FIG. 2, the diameter of the end of the pipe A is increased, and the predetermined position of the end of the pipe B is expanded in a convex shape in a longitudinal section over the entire circumference. The end of the tube B is inserted into the end of the expanded tube A. At the same time as the insertion, the aluminum conductors 7 and 17 at the center of the tube are automatically connected via the plug-in contact 8. Next, the contact portion between the distal end surface of the tube A and the convex side surface of the tube B is welded over the entire circumference. Metal pipes such as aluminum and iron are used for the pipes A and B, and the welding dust has conductivity and electrification. If this enters the pipes A and B, it may cause insulation breakdown of the cable in the pipeline air. Become. Therefore, a groove 9 is formed on the outer periphery of the tip of the pipe B, and a dustproof ring 31 is mounted in the groove 9 to prevent welding dust from entering the inside of the pipes A and B.

As the elastic tube constituting the dust-proof ring 31, as shown in FIG. 3, a ring formed by thermally fusing the end of a silicone rubber tube 2 having a high resistance to high-temperature deformation is used. I have. The silicon rubber tube 2 has minute air holes 4 on its front and rear surfaces.
The ventilation hole 4 prevents the inside of the tube from being evacuated by vacuum and the insulating ring is prevented from being deformed due to a pressure difference when the insulating gas is injected.

[0005]

The above-mentioned silicone rubber dust-proof ring has a large coefficient of friction and poor slipperiness. Therefore, when the pipes are inserted into each other, the dust-proof ring is dragged toward the inner surface of the pipe A to be pulled out of the groove. Sometimes popped out. For this reason, a fluororesin tube having a small coefficient of friction and a good sliding property was substituted.
However, the fluororesin dust-proof ring was deformed by welding heat because of its low-temperature deformation resistance, and it took time to recover. In addition, because heat fusion is not possible, as shown in FIG.
Although the string 11 passed through 10 is bound and formed into a ring shape, there is a problem that welding dust enters from a deformed portion due to welding heat and a gap 12 between the bound portions of the string.

[0006]

The present invention has been intensively studied in such a situation, and an object of the present invention is to provide a pipe air passage capable of reliably preventing welding dust from entering. An object of the present invention is to provide a dustproof ring for a cable connection. That is, the present invention is characterized in that, in the dustproof ring of the conduit air cable connecting portion comprising a ring-shaped elastic tube having a ventilation hole, the ring-shaped elastic tube is a ring-shaped silicon rubber tube coated with a fluororesin material. It is assumed that.

[0007] The dustproof ring of the present invention prevents deformation due to welding heat with a silicon rubber tube having a high resistance to deformation at high temperature, and is coated with a highly slippery fluororesin material when the tubes are fitted to each other. This prevents the dust ring from jumping out of the groove. In the present invention, PTFE (tetrafluoroethylene resin), PFA, EPT, FE is used for the fluororesin material coated on the silicone rubber tube.
Tetrafluorinated fluororesin materials such as P and ETFE are mainly used. Among them, PTFE has a particularly small coefficient of friction,
It is preferable because it has excellent heat resistance. Fluororesin composites reinforced with glass fibers or carbon fibers can also be used. By making the coating thickness of the fluororesin material as thin as possible and making the ring-shaped silicone rubber tube of the main body thicker, the high-temperature deformation of the dust-proof ring can be suppressed more reliably.

[0008] The production of the dustproof ring of the present invention is a method of coating the outer periphery of a ring-shaped silicone rubber tube having both ends heat-sealed with Teflon, covering the silicone rubber tube with a fluororesin tube to form a composite tube, A method of heat-sealing both end surfaces of the silicone rubber tube of the composite tube, a method of connecting and connecting a fluororesin-based heat-shrinkable tube to both ends of the composite tube, and the like are used. In the method (1), both end surfaces of the fluororesin tube are precisely cut so that no gap is formed between both end surfaces after the ring is formed. In this case, a step is reduced using a thin heat-shrinkable tube.

[0009]

The dustproof ring according to the present invention is obtained by coating a silicone rubber tube having high resistance to deformation at high temperatures with a fluoroplastic material having good slipperiness. Therefore, thermal deformation during welding is prevented by the silicone rubber tube having a high resistance to high-temperature deformation. In addition, the coating of the fluororesin material having good slipperiness prevents the dust-proof ring from jumping out of the groove when the tubes are inserted into each other. Since the silicone rubber tube can be heat-sealed, there is no gap at the joint and the ring can be easily formed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The dustproof ring of the present invention will be specifically described below with reference to embodiments. 1A to 1C are a front view and a cross-sectional view, respectively, showing an embodiment of a dustproof ring of the present invention. (Embodiment 1) The dustproof ring 1 shown in FIG. 1A is made of a ring-shaped silicone rubber tube 2 whose outer periphery is coated with a fluororesin material 3, and has vent holes 4 on the front and rear surfaces. The four vent holes 4 are provided on the front and rear surfaces, respectively, and the positions of the vent holes 4 on the front and rear surfaces are shifted from each other by 45 degrees so that the welding dust does not easily pass. The dustproof ring 1 is formed by fusing the end of a silicone rubber tube 2 into a ring shape by heat-sealing, applying a plastisol of fluororesin in a layered form, heating, cooling and curing to coat the fluororesin. Then, a heating needle was passed through the front and rear surfaces to form ventilation holes. The dustproof ring 1 has an advantage that the entire surface of the silicone rubber tube 2 can be thinly and uniformly coated with the fluororesin.

(Embodiment 2) The dustproof ring 11 shown in FIG.
Is a ring-shaped silicone rubber tube 2 covered with a thin fluororesin tube 5, and the end surfaces of the fluororesin tube 5 are in close contact with each other. The dustproof ring was manufactured by covering a silicone rubber tube with a Teflon tube and heat-sealing the end surface of the silicone rubber tube. Teflon 6C-J is used for the fluororesin tube 5
Tube (trade name, manufactured by Mitsui Dupont Fluorochemicals)
Was used.

(Embodiment 3) The dustproof ring 21 shown in FIG.
Is a composite tube in which a fluororesin tube 5 is covered on a silicon rubber tube 2 and the butted ends of the composite tube are connected by a fluororesin heat-shrinkable tube 6. TM-3028 Teflon TT
A joint (trade name, product sold by Tokyo Materials Co., Ltd.) was used.

Using the dust-proof ring of the present invention shown in FIGS. 1A to 1C and the conventional dust-proof ring shown in FIGS. 3 and 4, a cable having a total length of 310 m was laid in the air. The unit length of the conduit was 10 m, and six dustproof rings were used each. In the laying work, the end of the tube B to which the dustproof ring was attached was inserted into the enlarged diameter end portion of the tube A, and the aluminum conductors were simultaneously connected.
After welding the contact portions of the pipes A and B, the inside of the pipe was evacuated to a vacuum, and immediately after the deaeration, SF ₆ gas was sealed at a pressure of 5 kg / cm ² G (see FIG. 2).

After laying, the number of projecting points from the groove of the dust-proof ring and the presence or absence of welding dust were examined for all the welding points. The investigation was performed with a portable X-ray transmission tester.
Table 1 shows the results.

[0015]

[Table 1]

As is clear from Table 1, the sample of the present invention (N
In all of o.1 to 3), the dust-proof ring did not fly out of the groove, and in addition, the silicone rubber tube did not thermally deform, so there was no penetration of welding dust into the tube.
On the other hand, in No. 4 of the comparative example, the dustproof ring protruded from the groove at two of the six locations. This is because the silicone rubber has a large coefficient of friction, and the dust-proof ring was pulled toward the tubes when fitting the tubes together. Intrusion of welding dust was observed in the pipe at the location where this protrusion occurred. In No. 5, welding dust penetrated from the gap between the straps and the deformed portion of the dust-proof ring due to welding heat.

[0017]

As described above, the dust-proof ring of the present invention has good sliding properties of the Teflon of the coating layer, so that the dust-proof ring does not slide out of the groove when the pipes are inserted into each other. In addition, since the main body is made of a silicon rubber tube having a high resistance to high-temperature deformation, no gap is generated due to thermal deformation, and a ring is formed by heat fusion, so that no gap is formed at the joint. Therefore, by using the dustproof ring of the present invention, the inside of the pipeline is kept clean, and the power transmission in the pipeline air is stably performed for a long period of time.

[Brief description of the drawings]

FIG. 1 is a front view and a cross-sectional view showing an embodiment of a dustproof ring of the present invention.

FIG. 2 is an explanatory view of a connecting portion of a conduit air cable.

FIG. 3 is a front view and a cross-sectional view of a conventional dustproof ring.

FIG. 4 is a front view of a conventional dustproof ring.

[Explanation of symbols]

 1,11,21,31 Dustproof ring 2 Silicon rubber tube 3 Fluororesin material 4 Ventilation hole 5 Thin fluorine Resin tube 6 Heat shrink tube 7, 17 Aluminum conductor 8 Plug-in contact 9 Groove 10 Fluoro resin Tube 11 ……… String 12 …………… Gap between the ties of the strings A, B ……… Tube

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-14375 (JP, A) JP-A 58-3724 (JP, U) JP-A 59-97531 (JP, U) JP-A 60-60 177625 (JP, U) JP-A 6-21330 (JP, U) JP 7-23939 (JP, U) JP-B 45-11593 (JP, B1) JP-B 49-20297 (JP, Y1) (58) Field surveyed (Int.Cl. ⁶ , DB name) F16L 13/00-13/16 H01B 9/00-9/06 H01B 13/00 H02G 5/00-5/10 H02G 15/20-15 / 34

Claims (1)

(57) [Claims] 1. A dustproof ring of a conduit air cable connecting portion comprising a ring-shaped elastic tube having a ventilation hole,
A dustproof ring at a pipe air cable connection portion, wherein the ring-shaped elastic tube is a ring-shaped silicon rubber tube coated with a fluororesin material.