38 Acoustic Emission Testing for the Large Vacuum System …
431
According to NB/T 47013.9-2012 “Nondestructive Testing of Pressure Equipment
Part 9: Acoustic Emission Testing”, GB/T 18182-2012 “Acoustic Emission Testing
and Results Evaluation Methods for Metal Pressure Vessel”, JB/T 1076 4-2007
“Acoustic Emission Testing and Evaluation Methods of Nondestructive Testing for
Normal-pressure Metal Storage Tanks” and other standards, the existing mature
acoustic emission testing technology of pressure vessels is very difficult to be directly
applied to the acoustic emission testing of the large vacuum system under the vacuum
test state.
In order to carry out acoustic emission monitoring on key parts or typical defect
parts, explore the real-time monitoring and prediction methods for the evaluation
of defect activity, hazard degree and structural integrity. In order to improve the
pertinence of safety state monitoring and regular maintenance after the large vacuum
system is put into use, so as to effectively prevent the occurrence of various failure
and damage accidents, this paper aims at. Acoustic emission monitoring has been
carried out for the large vacuum system under the condition of vacuum pumping in
this paper.
38.2 Equipment Setup
This test is mainly aimed at the acoustic emission testing of the large vacuum system
in the vacuum test state. Before the vacuum test, the stress analysis and calculation
have been carried out by the Chinese Academy of special inspection, relevant design
and scientific research personnel, and the high stress distribution area of the whole
system has been determined. Under the vacuum test state, the inspection and detection
items carried out synchronously include the acoustic emission monitoring for the
stress concentration parts. Measurement, stress testing and strain monitoring.
The main location of acoustic emission monitoring is a high stress distribution
area, which is fillet weld connection of the pipe and the two billiard tanks. The process
adopts the characteristic parameter method. The pipeline part uses the triangle surface
positioning to arrange the sensor, and the ball tank part uses the area positioning
due to the complex structure with the internal existence of reinforcing ribs. There
are 12 sensors arranged around the fillet weld connection of the V-06 vacuum ball
tank and the pipeline. It is divided into two regions. Two sensors are symmetrically
arranged at 2700 mm away from the fillet weld on the pipeline, and the first region
is formed by arranging five sensors equidistant from the edge of the fillet weld. Five
sensors are arranged equidistant on the circumference of 2800 mm with the center
of the pipeline as the circle point, and the second region is formed by arranging five
sensors equidistant from the edge of the fillet weld. Similarly, the third and fourth
region are arranged around the fillet weld of the V-05 vacuum ball tank and pipeline.
The arrangement of sensors in Region II is shown in Fig. 38.2.
431
According to NB/T 47013.9-2012 “Nondestructive Testing of Pressure Equipment
Part 9: Acoustic Emission Testing”, GB/T 18182-2012 “Acoustic Emission Testing
and Results Evaluation Methods for Metal Pressure Vessel”, JB/T 1076 4-2007
“Acoustic Emission Testing and Evaluation Methods of Nondestructive Testing for
Normal-pressure Metal Storage Tanks” and other standards, the existing mature
acoustic emission testing technology of pressure vessels is very difficult to be directly
applied to the acoustic emission testing of the large vacuum system under the vacuum
test state.
In order to carry out acoustic emission monitoring on key parts or typical defect
parts, explore the real-time monitoring and prediction methods for the evaluation
of defect activity, hazard degree and structural integrity. In order to improve the
pertinence of safety state monitoring and regular maintenance after the large vacuum
system is put into use, so as to effectively prevent the occurrence of various failure
and damage accidents, this paper aims at. Acoustic emission monitoring has been
carried out for the large vacuum system under the condition of vacuum pumping in
this paper.
38.2 Equipment Setup
This test is mainly aimed at the acoustic emission testing of the large vacuum system
in the vacuum test state. Before the vacuum test, the stress analysis and calculation
have been carried out by the Chinese Academy of special inspection, relevant design
and scientific research personnel, and the high stress distribution area of the whole
system has been determined. Under the vacuum test state, the inspection and detection
items carried out synchronously include the acoustic emission monitoring for the
stress concentration parts. Measurement, stress testing and strain monitoring.
The main location of acoustic emission monitoring is a high stress distribution
area, which is fillet weld connection of the pipe and the two billiard tanks. The process
adopts the characteristic parameter method. The pipeline part uses the triangle surface
positioning to arrange the sensor, and the ball tank part uses the area positioning
due to the complex structure with the internal existence of reinforcing ribs. There
are 12 sensors arranged around the fillet weld connection of the V-06 vacuum ball
tank and the pipeline. It is divided into two regions. Two sensors are symmetrically
arranged at 2700 mm away from the fillet weld on the pipeline, and the first region
is formed by arranging five sensors equidistant from the edge of the fillet weld. Five
sensors are arranged equidistant on the circumference of 2800 mm with the center
of the pipeline as the circle point, and the second region is formed by arranging five
sensors equidistant from the edge of the fillet weld. Similarly, the third and fourth
region are arranged around the fillet weld of the V-05 vacuum ball tank and pipeline.
The arrangement of sensors in Region II is shown in Fig. 38.2.