A diagnostic tool for the quality control of gear pumps

This work proposes the use of a diagnostic tool based on the triple application of the Fourier Transform to carry out the quality control of gear pumps. The signal analysed is the discharge pressure acquired with a piezoelectric sensor in contact with the fluid near the discharge hole. An analysis was carried out by comparing the behaviour of a set of pumps having the same nominal characteristics but with various types of defects in the gear teeth, which had been made for the purpose of this experiment. A mathematical model of the diagnostic signal for the defective pumps was also developed. This model makes it possible to interpret the diagnostic signal processed with the triple application of the Fourier Transform and detect the presence and position of defects consisting in small scratches in tooth profiles. The tool makes it possible to obtain an acceptance mask for a set of gear pumps of the same series in which the category and size of a defect can be detected.