Polyethylene tape coating quality standards to judge and inspection method

coating quality standards include the following aspects:

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1) Apparent:

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apparent quality determines the quality of winding, therefore, the surface should be smooth, uniform lap, without buckling, no bumps, are not allowed to have a rupture point. If the tangle play tool operation earnestly, the defect can be avoided. But sometimes have bubbles in the process of winding, this situation occurs when the weather is hot, sunny when wrapping tape. Since the tape itself has certain elasticity and repair ability, the bubbles can disappear by oneself, to this kind of bubble is not a quality problem; If the permanent bubble, like buckling, repair should be removed.

2) Thickness:

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thick aromatic index of anticorrosion has very big effect to the quality, especially the rubber thickness increase can enhance the anti-corrosion ability. When the tape to determine, the structure is determined, its thickness is determined, therefore, the determination of the thickness of the tape in advance the total thickness can be determined. But in order to prevent the use of different batches of tape thickness, the analyst can use the thickness gauge after the determination of the construction of pipelines. Can determine the electric spark leak detection voltage.

3) Bond ( Peel strength)

bond refers to the rapping anticorrosive coating on steel pipe, it is directly related to the quality of the coating, its size directly affect the penetration of water. So make sure have enough cohesive force. Field test to imitate DIN 30670 standard, which USES a knife along the ring to open 10 mm wide belt, and then with spring balance and wall into 90 ° Angle slowly pulled open, open speed should not be greater than 10 mm/min, cohesive force should be greater than 8. 0 n/cm, the tests shall be carried out after the cover tape 2 h, anticorrosion pipeline should be test 3 per kilometer. Each project, each batch of tape measure three sets of data.

4) Electric spark leak detection:

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in the main control of the defect in the construction or some defects existing in the belt, must all pipe inspection. The same leakage voltage and petroleum pitch leakage formula. Leak detector movement speed less than 0. 3 m/s, the place should be marked on all discharge, then tape repair. Content of test results shall be recorded, including defect shape, nature and position, the repairing process, etc. , as a pipe completion data.