| 摘要 |
1530952 Measuring pressure electrically EXXON NUCLEAR CO Inc 5 March 1976 [13 March 19751 08928/76 Heading GIN The pressure of a pressurized system e.g. a nuclear reactor fuel rod is measured by placing in the system a sensor of a material whose permeability is dependent upon stress and monitoring the changes in permeability by applying a magnetic field to the sensor from outside the system. A cylindrical nuclear reactor fuel rod element, Fig. 3. (not shown) is sealed at one end by end-plug 12 in the shank 13 of which is positioned a cylindrical magnetostrictive ferrite sensor 14 in which is sealed an atmospheric gas by end caps 16, 18. The sensor is held in position by spring 20 acting on retaining cap 22 provided with aperture 24 through which gas from the fuel rod passes and applies stress to the sensor 14. A coil 40, Fig. 4, supplied with constant A.C. from generator I 2 is wrapped around shank 13 and the output thereacross is fed to one input of differential amplifier 42 to the other input of which is fed the output from coil 38 associated with a reference sensor maintained at ambient pressure and temperature. The output of amplifier 42 is then fed via summing amplifier 43 to a phase sensitive discriminator in the form of an A.C. to D.C. converter comprising analog multiplier 56 and filter 58, 60, a reference signal being fed to multiplier 56 from phase shift bridge 48. The output from capacitor 58 is proportional to the changes in reactance of coil 40 and hence pressures. During initial calibration the output from amplifier 43 is nulled by a signal from phase shift bridge 46. |
