JPH0214593B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for preventing gas _leakage at a threaded joint of a gas pipe. Gas leak prevention for repairing small amounts of gas leaks from threaded joints in elbows or sleeves of gas pipes (the amount of leakage that is found to be similar to crab bubbles by applying soapy water to the leakage point). It is about the method.

[Prior art] When a small amount of gas leaks from the threaded joint P of the sleeve 01 in a low-pressure city gas supply conduit as shown in Fig. 1A, the gas supply is temporarily stopped and the exposed pipe is replaced with a pipe with a diameter of 50 mm or less. In this case, as shown in Fig.
The repair method is to fill the pipe 02 with a sealant, and in the case of a pipe with a diameter of 80 mm or more, the method is to unroll the pipe and join it with the flange 03, as shown in Figure 1C. ing.

[Problems with the prior art] The conventional method for repairing gas leaks from threaded joints is as described above, so it is relatively easy for small-diameter gas pipes, but it is relatively easy to repair gas leaks from exposed pipes with a diameter of 80 mmφ or more. In this case, there are restrictions on the joints that can be connected. In addition, the only way to repair existing piping, especially in high places, is to join it with flanges, and as mentioned above, it is often difficult to connect it with other piping when unrolling and joining the gas pipe. In addition, as mentioned above, when performing the repairs shown in Figures 1 and 2, regardless of whether the pipe is a small diameter pipe or a large diameter pipe, it is necessary to first shut off the gas, so negotiations with the customer and subsequent ignition tests, etc. Another problem is that it requires a lot of time and effort.

An object of the present invention is to propose a method for preventing gas leakage that can reliably prevent gas leakage from a threaded joint by an extremely simple method, regardless of the diameter.

[Means for Solving the Problems] In order to achieve the above object, the present invention uses a sealant with extremely high sealing properties in a double manner. Wrap the hot melt agent processed to By blowing hot air from the outside of the agent using a hot gun, each hot melt is melted, and in particular, the string-shaped hot melt agent is used to plug the gas leakage point, and the sheet-shaped hot melt agent is widely covered, and the hot melt agent is covered with insulation cloth or The net is used to block the molten hot melt and seal the entire area uniformly.

In addition, as the string-like hot melt agent and the sheet-like hot melt agent in the present invention, thermoplastic polymers, thermoplastic rubbers, tackifying resins, waxes, filler plasticizers, mixtures of antioxidants, etc. with strong adhesive strength are used, for example. be done. Further, it is a condition that the reinforcing material made of insulation gauze or mesh used in the sheet-like hot melt agent is not easily melted by heat.

[Example] First, when performing repairs, first inspect the amount of leakage in advance. For example, check for bubbles with soapy water and find that the amount of leakage is about the same level as crab bubbles and that there is sufficient ventilation. The invention is practiced only in locations such as exposed piping. The string-like hot melt agent 1 used in the practice of the present invention has a long structure as shown in FIG. On the other hand, the sheet-like hot-melt agent 3 has a structure in which a reinforcing agent 4 made of a net or diaphragm is laminated together, as shown in FIG.

Next, an example of repair work will be explained based on FIG. First, use a wire brush and cloth to thoroughly clean the area around the threaded joint P between the gas pipe 5 and the joint pipe (joint pipe) 6, where the gas is leaking, to remove oil, rust, dust, etc., and then apply the 100V , preheat the area around the seal using an 800W hot air gun 7, and then apply the string-shaped hot melt agent 1.
is wrapped around the gas leak point (threaded joint P), and the hot-melt agent 1 is heated and melted using the hot air gun 7 again. 1.0mm reinforced
The hot melt agent 2 in the form of a thick sheet is wrapped tightly around the gas pipe 5 and the joint tube 6 so as to cover the string hot melt agent 1, and the hot melt agent 7 is again used to uniformly heat the entire body to melt the hot melt. After waiting for the hot melt to solidify, use a gas leak alarm and check for air bubbles using soap and water to confirm that there are no leaks from the sealed area and complete the work.

In addition, as shown in FIG.
If the internal space is large when wrapped, it is necessary to wrap another sheet-like hot melt agent 8 around the gas pipe 5 side, increase the outer diameter of the gas pipe 5 side, and reduce the level difference.

Next, in the above embodiment, preheating is performed before wrapping the string-like hot melt agent 1, but this is not necessarily necessary. In addition, in the example, after the string-like hot-melt agent 1 was wrapped around the string-like hot-melt agent 1, the string-like hot-melt agent 1 was heated and melted using a hot air gun.
When the string-like hot-melt agent 1 is melted together with the sheet-like hot-melt agent 2 by wrapping the sheet-like hot-melt agent 2 around it and applying hot air from above, it is not necessary to heat and melt the string-like hot-melt agent 1 in advance. do not have.

[Effects of the Present Invention] As described above, the present invention is designed to perform double sealing using the string-like hot-melt agent 1 and the sheet-like hot-melt agent 2 when a gas leak occurs at the threaded joint of a gas pipe. Therefore, the following effects can be expected from the combined effect of both.

a Hot melt agent 1 processed into a string shape at the corner of the step between the gas pipe 5 and the joint pipe 6, which is the gas leak point
Since the hot melt is wrapped around the screw and heated and melted, the molten hot melt penetrates into the screw thread and solidifies, thereby closing the minute leakage gap.

b Since the sheet-like hot-melt agent 2 is wrapped around the outside of the string-like hot-melt agent 1, there is no fear that the string-like hot-melt agent 1 will flow out or drip when it melts, and therefore the gas leakage area can be evenly distributed. It is possible to seal it.

c. Since the sheet-like hot-melt agent 2 has a reinforcing agent 4 such as a cold gauze or a net attached to the outside thereof, when the hot-melt 3 of this sheet-like hot-melt agent 2 melts, due to the damming action of this reinforcing material 4, There is no need to worry about it flowing out or dripping, and even if holes are formed in the sheet-like hot melt agent 2 due to excessive local heating with the hot air gun 7, the molten hot melt of the reinforcing material 4 will solidify when the heating is stopped. It has the effect of clogging and re-obstructing.

d Due to the effects of a, b, and c above, the gas leak location can be completely sealed, so there is no need to use a P pipe or a flange as in the past. Repair work is therefore very simple.

e Since the repair method involves wrapping string-like hot-melt agent 1 and sheet-like hot-melt agent 2 around the gas leak and heating and melting them, it is recommended to use this method when repairing city gas pipes in exposed pipes or in areas with sufficient ventilation. , there is no need to stop the gas supply every time, and therefore no pre- and post-measures are required when stopping the gas. Furthermore, there is no need to inconvenience customers by shutting off the gas supply.

[Brief explanation of drawings]

Figure 1 A, B, and C are explanatory diagrams of a conventional gas leak repair method. Figure 2 is a perspective view showing a part of a string-shaped hot melt agent. Figure 3 is a perspective view showing a part of a sheet-shaped hot melt agent. , FIG. 4 is a sectional view of a screw joint where gas leakage was repaired according to the present invention, and FIG.
The figure is a cross-sectional view showing a state in which when the difference in level between the joint pipe and the gas pipe is large, repair is performed after wrapping a sheet-like hot melt agent around the gas pipe to reduce the difference in level. 1... String-like hot melt agent, 2... Sheet-like hot melt agent, 3... Hot melt, 4... Reinforcement material.

Claims (1)

[Claims] 1. In repairing a leak from a threaded joint of a gas pipe that is supplied at low pressure and has a small amount of leakage, a string-like hot melt agent is applied to the outside of the threaded joint between the gas pipe and the joint pipe. a first step of wrapping the string-like hot-melt agent; a second step of wrapping a sheet-like hot-melt agent reinforced with cold gauze or netting so as to cover the string-like hot-melt agent, the gas pipe, and the joint pipe on the outside of the string-like hot-melt agent; A method for preventing gas leakage at a threaded joint of a gas conduit, comprising: a third step of heating the sheet-like hot-melt agent from the outside using hot air to melt the string-like hot-melt agent and the sheet-like hot-melt agent. 2. A method for preventing gas leakage at a threaded joint of a gas conduit according to claim 1, wherein the wound portion is preheated before the string-like hot-melt agent and the sheet-like hot-melt agent are wound. 3. A method for preventing gas leakage at a threaded joint of a gas conduit according to claim 1, in which a sheet hot melt agent having the same structure as the sheet hot melt agent is wrapped in advance on the side of the gas conduit around which the sheet hot melt agent is wound. . 4. A method for preventing gas leakage at a threaded joint of a gas conduit as claimed in claim 1, which comprises wrapping a string-like hot-melt agent around the wound, heating and melting the string-like hot-melt agent, and then wrapping a sheet-like hot-melt agent around the string-like hot-melt agent.