| 摘要 |
<p>1473859 Detecting particles in fluid stream MOBIL OIL CORP 6 Dec 1974 [7 Dec 1973] 52844/74 Addition to 1435971 Heading G1G The parent invention is modified in that the presence of particles in a fluid-flowing through a conduit is detected by arranging a probe on the outside of the conduit to detect acoustic energy generated by impingement of the particles on the conduit wall. Fig. 2 shows the probe mounted on a bend in conduit 10. The probe comprises a Piezo-electric element 20 supported by its leads 21, 23 in a housing 15 attached by epoxy resin or welding to the conduit. The housing is filled with oil via inlet 25 after the attachment, or may be prefilled if a membrane is fixed across the housing end which abuts the conduit. A coil 31 tunes the element 20 to its primary resonant frequency in the thickness mode. The probe signals are amplified, filtered and rectified to feed a recorder and alarm.</p> |
