| 摘要 |
The present invention lengthens the life of a sensor unit that, using a corona discharge, detects the amount of microparticles in a gas containing microparticles. The sensor unit (300) contains: ion-generating units (611, 361, 322) that generate ions; a charging unit (612) that, using the ions (PI), charges at least a portion of the microparticles (S) in the gas containing microparticles (S); capturing units (616, 617, 316, 326, 362) that capture at least a portion of the ions (PI) not used to charge the microparticles (S); and sensor ground units (340, 310v, 330v3) connected to the capturing units and having a first floating potential that is in accordance with the amount of ions (PI) not used to charge the microparticles (S). The sensor unit (300) can detect the amount of microparticles (S) in the gas in accordance with the potential of the sensor ground units. The sensor ground units are covered by an insulating ceramic at the sections that contact the gas and are at the outside of the sensor unit (300) |
