35 Acoustic Emission Testing of Energy Field Objects
405
35.3 AE Valve Leak Detection
In addition to pipelines there are a lot of valves units on TPP. One of the main
operation parameters of valve is tightness. In the result, detection of valve tightness
and leakage value of valve is relevant task. As it is known AE method has high
sensitivity for detection of gas and liquid leak [1].
Automatic leak detection function, realized in portable 2 channel device UNISCOPE can be used for leakage detection of valve (Fig. 35.2) [1, 2].
This function consists of 3 stages (Fig. 35.3). The first stage consists of setting
valves characteristics and parameters of their operation (Fig. 35.3a). At the second
stage, data are collected in accordance with the measurement scheme (Fig. 35.3b).
The data are collected by change the sensor position to the points indicated in the
schematic drawing, which is located on the device screen. At the same time, automatic
noise filtering, identification of the leakage signals and calculation of the leakage
value on the basis of the empirical equation are carried out. And at the last, third
stage, a report is generated (Fig. 35.3c), with a conclusion about the tightness/non
tightness of the valves, and the leakage value (if the valves are non-tight).
At that, testing time of valve unit depends from flow diameter and takes from 1 to
15 min. Minimal value of leakage which can be detected is about 1 l/min for gases
and 0.2 l/min for liquids. The relative error is about 20%.
Fig. 35.2 UNISCOPE
device
a
b
c
Fig. 35.3 a–c Examples of UNISCOPE software in leak detection mode
405
35.3 AE Valve Leak Detection
In addition to pipelines there are a lot of valves units on TPP. One of the main
operation parameters of valve is tightness. In the result, detection of valve tightness
and leakage value of valve is relevant task. As it is known AE method has high
sensitivity for detection of gas and liquid leak [1].
Automatic leak detection function, realized in portable 2 channel device UNISCOPE can be used for leakage detection of valve (Fig. 35.2) [1, 2].
This function consists of 3 stages (Fig. 35.3). The first stage consists of setting
valves characteristics and parameters of their operation (Fig. 35.3a). At the second
stage, data are collected in accordance with the measurement scheme (Fig. 35.3b).
The data are collected by change the sensor position to the points indicated in the
schematic drawing, which is located on the device screen. At the same time, automatic
noise filtering, identification of the leakage signals and calculation of the leakage
value on the basis of the empirical equation are carried out. And at the last, third
stage, a report is generated (Fig. 35.3c), with a conclusion about the tightness/non
tightness of the valves, and the leakage value (if the valves are non-tight).
At that, testing time of valve unit depends from flow diameter and takes from 1 to
15 min. Minimal value of leakage which can be detected is about 1 l/min for gases
and 0.2 l/min for liquids. The relative error is about 20%.
Fig. 35.2 UNISCOPE
device
a
b
c
Fig. 35.3 a–c Examples of UNISCOPE software in leak detection mode