New view on debris equilibrium concentration and oil sampling in machine system

In order to seek the deep reason of poor result reappearance and poor precision in ferrograph, this paper analyses the numerical characteristic of distribution function of debris concentration in machine lubricant cycling system by solving the stochastic differential equation, then revised the concept of debris equilibrium concentration and put forward a new concept which is that debris concentration in a machine trends towards a wide stationary processes from a non-stationary processes on the conditions where the running parameters are not changed and the white noise is introduced as a random component and some test results are given. Eventually a new oil sampling concept is advanced in oil condition monitoring and ferrographic technology, which is the method of oil sampling should be on-line sampling or larger volume (>100 mL) off-line sampling in order to get the time average or the space average.