Application of improved EMD algorithm for the fault diagnosis of reciprocating pump valves with spring failure

This paper presents an improved EMD algorithm for the fault diagnosis of reciprocating pump valves with spring failure. The vibration signal of reciprocating pumps is of typical nonstationarity. Although the EMD algorithm adopting the cubic spline interpolation is an effective tool processing non-stationary signal, it couldnpsilat accurately extract fault characteristics from the highly nonstationary signals. So the paper presents a new improved EMD algorithm which adopts Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) as envelope of extrema. Through the simulation and application, it can be shown that the PCHIP can extract fault characteristic of valves more exactly than the spline.