Nozzle and working-condition classifications for water jet systems

In this paper, a technique for assessing both the working and healthy conditions of water jet-system nozzles is presented. The proposed classifier is based on the discrete Fourier transform (DFT) of the instantaneous electrical power signal. With this in mind, it will be shown that the electrical power signal supports all necessary information to characterize both the working condition of the system and the nozzle type. Furthermore, the same signal can be analyzed with the aim of predicting the presence of an incoming faulty behavior. The presented technique is also used to build a second type of classifier. While the first one is of general application, the second one can be used when the properties of the orifice are known, and only the working conditions have to be classified. Results show the effectiveness of the proposed approach, which, due to its simplicity, can be embedded in a low-cost realtime diagnostic system. For the sake of clarity, a brief description of a water jet system is also presented.