| 摘要 |
PURPOSE:To accurately measure concentration of oxygen without causing any influence due to variation of heat conductivity of gas to be measured, by detecting leakage flux of magnet by detection means of magnetic flux density and measuring concentration of oxygen of the gas to be measured. CONSTITUTION:A reference system 10 is composed of a core 12, an exciting coil 13 and a power source 14 and is equipped with an electromagnet 11 turning a magnetic pole 122 into N pole and a magnetic pole 121 into S pole by a reference electric current Ir which is allowed to flow to the coil 13 and a case 15 filled with the reference gas. A measuring system 20 is composed of a core 22, an exciting coil 23 and a power source 24 with a variable mechanism 241 and is equipped with an electromagnet 21 turning a magnetic pole 221 into N pole and a magnetic pole 222 into S pole by a control current Ic which is allowed to flow to the coil 23 and a case 25 in which the gas to be measured in allowed to flow. A sensor 30 is a sensor part in measuring apparatus of magnetic flux density. When a leakage flux of the electromagnet 11 is phir and that of the electromagnet 21 is phic, these leakage fluxes are detected by the sensor 30 differentially and the output Eo is proportional to the concentration of oxygen of the gas to be measured. |
