The Method Of Wavelet Packet On Fault Diagnosis For Reciprocating Compressor Valves

In recent years, machinery fault diagnosis technology has been greatly developed all over the world. It is rather difficult to monitor the state of reciprocating compressor owing to its complex construction and so many stimulation sources. Gas valve fault diagnosis is my study point. Based on traditional fault diagnosis means and classicla signal process, this paper adopts the methods of wavelet analysis and wavelet packet on sinal process, to find valve eigenvector. Using this method, gas valve fault diagnosis is effectively solved for reciprocating compressor.The contents of this dissertation mainly include the following aspects. Primarily, this paper analyses and introduces configuration and dynamic character of reciprocating compressor. It is pointed out that vibration of reciprocating compressor is because of crankshaft, link arm and piston working. Secondly, this paper analyses stress of the valve, gets the estimating formula of the stress of the straight impaction of the valve plate against the lift limiter and the valve seat, and the main reason for the vavle plate failure is great dynamic stress. Thirdly, the paper expounds the theory of wavelet and wavelet packet, and the process of using wavelet packet to get energy characteristic vector. By means of normal and failure valve signal measured, it analyses fault mechnaics. It is pointed out that among all the factors leading to vibration of valve, gas pulsation, operation of the reciprocating compressor and the impaction of the valve plate against the lift limiter and the valve seat is chief factors. Fourthly, a programme for fault diagnosis of reciprocating compressor valve was developed with environment of Visual Basic.NET and MATLAB software, which make it convenient for engineering.