Non destructive testing of low-temperature storage tanks and ultrasonic phased array technology

1、 Factors in Non destructive Testing of LNG Storage Tanks Non destructive testing is an important measure for the operation of LNG storage tanks, which has high risks and technical requirements. Therefore, some factors are often hidden. Based on actual conditions, it can be roughly summarized as follows: 1. Insufficient qualifications of non-destructive testing personnel Low temperature storage tank inspectors are personnel with corresponding professional qualifications and mastery of LNG storage tank testing technology. They should understand the technical regulations, relevant product standards, technical documents and drawing provisions of LNG storage tank equipment. However, in actual practice, some testing personnel have not undergone specialized training and assessment, do not have the corresponding inspection qualifications, lack technical expertise, have weak awareness and work responsibility, and some testing personnel lack a rigorous work attitude and cannot handle this job with caution.

2、 The environment for non-destructive testing operations is also influenced by many factors. LNG storage tanks are generally placed in poorly lit, poorly lit, poorly ventilated, and tightly sealed spaces. The buildings that hold the containers are not sturdy, have poor hygiene conditions, and have not been ventilated. This can seriously affect the patience and vision of the testing personnel, and can seriously affect their work attitude. If the containers containing materials are not cleaned and replaced, and the concentration of residues is not measured, it can also cause harm to personnel entering the container for testing.

3、 Violation of regulations and failure to take corresponding measures

When entering LNG storage tanks for non-destructive testing, ignoring prohibition or warning signs will bring serious consequences to the testing work.

. For example, not cutting off the power supply of rotating components, not replacing or conducting qualified tests in areas with radiation sources, and leaving no one outside to supervise. Poor protective measures and ineffective protection against radiation sources are often due to inspection personnel violating regulations and failing to take corresponding measures as required.

4、 A good start is half the battle if the non-destructive testing system is not sound or complete. When the testing system is not sound or complete, inspectors cannot receive systematic education, and it may even lead to immature or improper selection of testing personnel, failure to formulate corresponding measures before testing, non-standard testing organization, unclear responsibilities of each person, improper work of on-site command and dispatch personnel, and unauthorized departure of supervisors from their positions. These are all factors that cause personal injury.

II. LNG Storage Tank Ultrasonic Phased Array Technology

Phased Array Ultrasonic Non destructive Testing Technology (referred to as Ultrasonic Phased Array Technology) is a recent development in ultrasonic non-destructive testing. The application of Ultrasonic Phased Array Technology began in the 1960s, and the basic concept of Phased Array Ultrasonic comes from Phased Array Radar Technology.

. Ultrasonic phased array technology can generate the same sound beam and angle as conventional ultrasound, but it differs from conventional ultrasound detection in that it can electronically control the angle and focal size of the sound beam. The development of ultrasonic phased array technology in non-destructive testing is limited due to its complex theory and high instrument and testing costs. However, in recent years, ultrasonic phased array technology has received attention from the non-destructive testing industry for its flexible beam deflection and focusing performance.

The advantages of ultrasonic phased array technology are flexible operation, accurate defect positioning, low operation intensity, no radiation, no dirt. For example, for the detection of circumferential welds in gas storage tanks, only a simple linear scan is needed to complete the detection of the entire weld, and complex or difficult to access parts can be detected. While scanning, the weld can also be analyzed and evaluated. The detection results are also intuitive and can be displayed in real time, and can be printed or saved for long-term preservation of the detection results.

. Its limitations include high requirements for surface roughness of the tested object, relative sensitivity to temperature, expensive equipment, and high requirements for personnel quality.