Sensor for inpinging particles in a fluid,having a high pass filter for discriminating bubbles

摘要

An up tp 100 micro m thick ceramic plate (14) with an up to 100 micro m thick piezoelelectric film (20) is arranged as an axial flow particle sensor element. Primary resonance frequency is 300 kHz. Metal particles up to 50 micro m in size are distinguished from bubbles by using a high-pass filter with a higher cut-off frequency of 320 kHz to 1.8 MHz. Frequency upper limit is 10 MHz. <IMAGE>