Pipeline failure and maintenance -11

Release time:

2024-04-29

How about the new technology of plugging pipeline under pressure?

(5) Plugging process

1) Preparation work: A. first determine the material and size of components at the leakage position, understand the pressure, temperature and other parameters of the system medium, carefully check whether there are cracks and serious corrosion on the connection parts at the leakage position, if necessary, measure the thickness, and formulate the leakage stoppage plan; B. design and make appropriate clamps for sealing according to the actual situation on site, and select the corresponding sealant; C. install the scaffold required for construction; D. wear Good special work clothes, full hats, gloves and protective glasses, etc.

2) Plugging construction: A. align the fixture with the leakage position and fasten it. B. Install the cylindrical sealant into the syringe, and connect the hydraulic cylinder, plunger push rod and the syringe with the connecting nut. C. Connect the hydraulic pump, high-pressure hose, injection gun and pressure gauge together with the connecting joint, and close the unloading valve of the hydraulic pump. D. Connect the injection hole on the joint fixture of the injection gun, and shake the pressure rod of the hydraulic pump to pressurize. When a certain pressure is reached, the pressure gauge pointer will rise and fall, swing back and forth, indicating that the sealant is flowing. When the pointer of the pressure gauge rises straight again without falling, it means that the sealant injection is completed. E. Slowly open the hydraulic pump unloading valve to return the plunger to its original position. F. Inject from the injection hole farthest from the leakage point in sequence, and then gradually to the point near the leakage point until it is completely blocked and stabilized for several minutes.

(6) Precautions

1) It is extremely toxic to the medium, and the pressure parts of the pipeline leak because of cracks. In the original design, the leakage point of the lens gasket seal and the pipeline erosion thinning is unknown, so it is not easy to use this method.

2) Plugging under pressure shall be approved by the competent department. For the plugging of high-pressure, toxic, harmful, flammable and explosive medium pipelines, the approval of the leader in charge shall also be obtained.

3) Before construction, relevant technical personnel and safety personnel shall go to the site for investigation, make specific construction scheme, formulate effective operation requirements and safety protection measures, and report to the leader in charge for approval.

4) Operators who apply pressure plugging must be specially trained by relevant departments and can only operate after passing the examination.

5) In order to ensure the safety of operation, the plug of injection joint must be closed before connecting, removing the injection gun and taking out the dense sealing agent of push rod. When continuing to inject sealant, it is necessary to apply certain pressure to the sealant in the injection gun before opening the cock of the injection joint.

6) Plugging under pressure is a temporary measure, which shall be removed when the system stops, and the leaking part shall be completely repaired.