A case study: Monitoring heat exchanger based on vibration sensors and nondestructive testing technique
Flow-induced tube vibration could cause serious damage on large-scale circulating-water heat exchanger in factories, e.g., atomic reactors, nuclear power plants, petroleum and chemical industry. Therefore, efficient inspection technology is very important for heat exchanger's blockage and leakage. The existing detection technologies, like temperature test and pressure test, are very easily affected by extraneous factors, e.g., temperature and pressure, while the nondestructive testing technology based on vibration sensors is free from above limits. In this paper, we use vibration sensors to detect blockage and leakage of the circulating-water heat exchanger. According to the experimental results, it is found that when detecting heat exchanger's blockage and leakage with vibration sensors, environmental vibration from the working machines has influence upon the result, while pump vibration and vibration produced by liquid flowing through regulating-valve make little difference. Nevertheless, fault diagnosis of large-scale circulating-water heat exchanger, which uses nondestructive testing technology based on vibration sensors, needs to be further improved.
Rotating Machinery Concurrent Fault Diagnosis Based on Artificial Immune System and Evidence Theory
A model of multi-parameter comprehensive diagnosis system was proposed with respect to the facts that it was difficult to distinguish during the fault diagnosis process of rotating machine.The evidence theory has the advantages of representation of uncertainty,measurement and portfolio.The introduction of artificial immune system to solve the defects of evidence theory,the artificial immune system and fault diagnosis as a method of solving concurrent faults.This method is verified and provides a new way to solving concurrent faults.
Monitoring and Optimization of Internal Grinding Process
Summary The grinding process is influenced by many factors such as grinding wheel characteristics, dressing conditions and, course, grinding conditions. Therefore, it is difficult to perform the grinding operation in an optimum state. In this study, in-process monitoring methods using power and acoustics emission sensors are proposed to detect malfunctions in the internal grinding process. In addition, a new internal grinding cycle featuring rapid indeed is proposed to minimize the grinding cycle time.