Search

This paper analysises and evaluates vibration situation and gives the general procedure for vibration analysis of pumps units, which contain determination of each evaluation matter-element and comprehensive evaluation method based on matter-element. Evaluation matter-element is established by evaluation system of pumps vibration, aimed at a particular example. The factors affecting the vibration of the pump unit has three major factors of the mechanical, hydraulic, electrical, sub-factors of the three factors. According to the characteristics of the pump unit vibration and the current technical condition, the vibration is divided into five levels: most serious, more serious, normal, minor, and slight. The evaluation weight matter-element are established by using AHP, weight are determined by using the combination of AHP and entropy, finally comprehensive evaluation of pumps vibration performance is practiced. Thus, this evaluation is feasible and useful.

A technique of feature extraction based on vibration phase diagram for roller of rolling mill was discussed. Basic theory of roller fault diagnosis based on vibration phase diagram was presented, causes for phase diagram under different conditions was analyzed and a method of computing the eigenvalue for distribution density matrix was provided. To same one roller vibration under identical environment, the cooperation of phase point probability distribution is only relelation to the density of probability distribution, and unconcerned with noise. It is also different to phase point distribution density of different states. A experiment was conducted on ψ500×2 shrewd roller of rolling mill, the feature of roller signal was extracted based on vibration phase diagram and chose Hidden Markov Model (HMM) to build and identify mould. The experiment shows that this system has better identification rate, and proves that this technique is effective.

This paper studies on the design methods and key technologies of the system of rolling mill equipments management based on Web, in accordance with the the practical needs. This system adopted B/S as its structure, while developing software for rolling mill equipments management on the platform of Microsoft Visual Studio.NET. The system uses a three-tier hierarchical structure: User layer, Web Server layer and Database server layer. User layer refers to the user through the browser to complete the system remote services and information sharing. Web server layer is the link to contact the browser and the database, and used to store system function modular and application program. Database server layer is mainly used to store various data required for the system after being put into practice for a period, the efficiency of maintenance and management of rolling mill equipments has been increased obviously, thus the method can be used in the maintenance of rolling mill equipments.

A kind of signal build mould and identification tool for roller of rolling mill was discussed. Basic algorithm of Hidden Markov model (HMM) theory was presented. For ψ500×2 shrewd roller of rolling mill, the paper led Short-time Fourier transform (STFT) into draw the feature of roller signal and chose Continues Gaussian Hidden Markov Model (CGHMM) to build and identify mould. The experiment installation major included: ψ500×2 shrewd rollers and roller performance test control work of rolling mill control machine as well as a set of online state inspection system. The experiment data was collected by two kinds: roller rotational speed from low to high and from high to low. The experiment shows that this system has better identification rate, and proves that this system is effective.

The profile of cycloid-arc screw compressor rotors is not a smooth profile, and it has a tip on it. When designing the hob cutter is used for machining this kind of rotors, the profile of hob edge will appear separation. In this paper, the design theory of hob cutter for hobbing the no-symmetric cycloid-arc rotor with tip profile is researched, and the best way for design this kind of hob cutter with a separate edge is attained according to practical design, manufacture and test. Its results are shown that it is good practice to design the hob cutter and hob the cycloid-arc rotor. Thus, the machining method for hobbing screw compressor can enhance high productivity and machining accuracy.