Development Of A Performance Test System For Filters

Filters are important components for contaminant control of hydraulic system.Its role is to filter out particles contamination, to keep the oil contamination level within the limit that the key hydraulic components can withstand, to ensure the reliability and extend component life.Recently, due to the exposure of the quality of filtration products, especially filter elements, the problem of performance test for filters causes the user and the manufacture's attention.Therefore, there is important practical significance to establish a performance test system for filters.The techniques of oil contamination level analysis and on-line monitoring and oil temperature precision control are studied in detail in this thesis.The development and key technology research of a performance test system for filters, not only provides conditions for carrying out the study of filters, but also promotes the performance of hydraulic systems.The system is capable of evaluating filtration performance of a filter element with multi-pass method and evaluating differential pressure versus flow characteristics and determination resistance to flow fatigue using particulate contaminant.The main contents of each chapter are summarized as follows:In chapter 1, the history and current research status of filter performance testing technology and test-bed are reviewed based on a lot of publications and conference papers. Key technology of performance test system is briefly introduced.Accordingly, the research and the goal of the project are brought forward.In chapter 2, according to the functional requirements, the overall design scheme of the performance test system is put forward, including analysis of technical parameter and evaluation indicators, the design of working principle of hydraulic circuit, and selection and design of key components. Several technical difficulties, such as the deposition of particles in the test circuit and size change problem, computer control system and uniform test benchmark to ensure the comparability of test results, are stated and the principles are explained.In chapter 3, the hardware and software of computer control system are developed, including the selection of upper and lower machine, the software development of the submitted-machine, and the software development of the main-machine.In chapter 4, based on the theoretical model for fluid power system contamination control, the influence factors are considered.The condition of remaining filter upstream particle concentration stable is to maintain the system oil volume to remain stable.Contaminate control experiment is made on the performance test system, the experiment results show that filter upstream particle concentration can quickly reach the steady state. In chapter 5, based on the mathematical model of temperature control object and 3-way proportional valve, the difficulties of oil temperature control are analyzed.A kind of oil temperature control strategy based on parameter self-tuning fuzzy PID control method is put forward.The parameter self-tuning fuzzy PID controller is designed.Oil temperature control experiment is made on the performance test system, the experiment results show oil temperature maintaining in 40±2℃.In chapter 6, some conclusions are given and some new views are put forward in the future.