Study On Online Monitoring And Analysis System For Liquid Ring Pump Working And Safety Performance

Liquid ring vacuum pump plays an important role in many fields, such as electric power, petroleum, coal, metallurgy, chemical industry, light industry, paper making, fire protection, municipal water supply and drainage etc.. It is a vital element in vacuum system, and its operating conditions directly affect the performance of the units stability. Thereby, there are lots of advantages for investigating on fault diagnosis methods. It is of great significance to make liquid ring vacuum pump work normally though monitoring its operating conditions and fault diagnosing.Fault diagnosis of liquid ring vacuum pump is a comprehensive multidisciplinary cross technology, which identifies and evaluates operating states quantitatively, and predictes remaining useful life through analyzing operating parameters. These signals consists of temperature, pressure, flow, shaft power, speed and vibration,additionally some contain potential information, especially the valuable vibration signals for fault diagnosis. In this paper, feature extraction of liquid ring vacuum pump’s observation signals and fault alert were studied deeply based on the theories of testing and virtual instrument techniques in real world, and a condition monitoring facility was proposed, which was helpful to improve fault diagnosis levels of liquid ring vacuum pump. The content is mainly as follows:(1)Based on the fault mechanism of liquid ring pump, analysis on its failure mode was performed. And a fault tree with “liquid ring pump can not operating normally ” was established as the top event. Then, minimum cut was set and structure importance were calculated by fault trees qualitative analyzing. Results show that “the fracture of the valve”, ”water shortage”, “the impeller and splitter eccentric wear” are the main factor leading to performance degradation of the liquid ring pump. "Hydraulic shock", "impeller damage", "bearing abnormal operation" are the main sources of vibration and noise of liquid ring pump.(2)The hardware design framework contained hardware selection, configuration of cable connections, and layout of observation points, was determined.(3)Software design of performance parameters real-time monitoring system of liquid ring vacuum pump was conducted based on virtual instrument technology by Lab VIEW code. The software run under WINDOWS platform, and Access database was used for data management. This software contained some modules, such as, data acquisition, data filtering, signal analysis, real-time display, fault alert and performance curve printing.(4)An experimental test facility was performed for measuring temperature, pressure, flow, shaft power, speed and vibration of liquid ring vacuum pump, which was successful to carry out for the experimental operation and performance test. Moreover, data was collected under different operating conditions. It helped to provide data support for studied feature extraction and fault diagnosis of liquid ring vacuum pump.