Machine wear measured by isotopes in oil circuit - using oil pipe passing through sodium iodide crystal detector

摘要

A device for measuring the wear of a machine part by measuring of the radioactive isotopes incorporated into the surfac elayer of the part, worn away and transported, e.g. in the lubricating oil, comprises a measuring head with a scintillation crystal. A sodium iodide crystal is used, with a transverse passage through it, through which a straight length of pipe is passed; the oil containing the radioactive worn particles is passed through this pipe. In the preferred arrangement, this pipe is vertical, with its inlet at the top, outlet at the bottom, and pref. also an upper vent pipe leaving upwards above the oil level to atmosphere or alternatively back into the oil circuit. Esp. for wear measurements in which the surface zone of the machine parts have been irradiated by heavy charged particles from an accelerator to produce radio isotopes in the surface. The resultant activity is about 1000 times less than that produced by an earlier method using thermal neutrons. Applicable to automobile engines. A simple tube replaces the earlier arrangement of a complicated measuring chamber. A higher concentration of worn particles and thus higher sensitivity is achieved. Lead shielding around the measurement head can be considerably reduced, thus saving in cost and weight. Contact surface between the medium, which possibly is hot, and the measuring unit is smaller, so that cooling is simplified. Flow resistance is reduced and thus the readings are virtually unaffected by operating conditions. Because the pipe is vertical, worn particles do not accumulate in it.