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What are the main methods for detecting finned tubes?
Dec 24, 2018

Embedded detection tube:

1) Double pipe should be buried in the pile diameter of 0.6-0.8m; three pipes should be buried in the pile diameter of 0.8-2.0m; four pipes should be buried in the pile diameter of 2.0m or more. According to the specific conditions of Chifeng Bridge, three pipes can be buried in the pile foundation.

2) The sound wave detecting tube should be made of steel pipe, plastic pipe or steel bellows, and its inner diameter should be 50-60mm. The connection of the test tube should be smooth transition, the nozzle should be higher than the top of the pile by more than 100mm, and the height of each test tube should be the same. The lower end of the tube should be closed, the upper end should be covered, there should be no foreign objects in the tube, and the tube body should not be damaged.

3) The test tube can be welded or bundled on the inside of the steel bar, and the test tubes should be parallel to each other.

On-site inspection of finned tubes

1) Determine the delay time t of the sound wave monitor transmitted to the receiving system before the on-site inspection. And calculate the sound time correction value.

2) When transmitting and receiving, the probe should be lifted at the same elevation or with a fixed height difference.

3) The measuring point distance is 40cm, and then encrypted to 20cm when an abnormality is found.

4) Select the appropriate transmit voltage and amplifier gain and leave it unchanged during the test.

5) Display and record the time history curve of the received signal in real time.

6) Combine multiple finned tubes with two inspection profiles to complete the inspection.

7) After each set of test tube test is completed, the test point should be randomly repeated 10%, and the relative standard deviation of the sound should not exceed 5%; the relative standard deviation of the amplitude should not exceed 10%.