Abstract: A condensation particle counter includes a saturation section, an aerosol inlet assigned to the saturation section, a condensation section, a measuring section for condensation particles, and an outlet section. The aerosol inlet allows a flow of an aerosol loaded with particles. Each of the condensation section, the measuring section and the outlet section are arranged downstream of the saturation section. A critical nozzle is arranged in the outlet section. The critical nozzle includes a critical nozzle inlet. A pump suctions the aerosol. An outlet line extends from the critical nozzle to the pump. A valve device is arranged in the outlet line between the critical nozzle and the pump. A pressure measuring device is arranged upstream of the critical nozzle inlet. The outlet line is entirely closed or partially closed by the valve device depending on a measurement value of the pressure measuring device.

Abstract: A condensation particle counter includes a saturation section, an aerosol inlet assigned to the saturation section, a condensation section, a measuring section for condensation particles, and an outlet section. The aerosol inlet allows a flow of an aerosol loaded with particles. Each of the condensation section, the measuring section and the outlet section are arranged downstream of the saturation section. A critical nozzle is arranged in the outlet section. The critical nozzle includes a critical nozzle inlet. A pump suctions the aerosol. An outlet line extends from the critical nozzle to the pump. A valve device is arranged in the outlet line between the critical nozzle and the pump. A pressure measuring device is arranged upstream of the critical nozzle inlet. The outlet line is entirely closed or partially closed by the valve device depending on a measurement value of the pressure measuring device.

Abstract: In order to effectively protect a particle measuring device (8) against temperatures that are too high and/or too low, it is provided that the temperature (T) of the sample gas is measured upstream of a first temperature-sensitive sample gas processing or sample gas measuring device (20, 21, 22, 42) in the particle measuring device (8) and that the measured temperature (T) is compared with a first and/or second limit value (To, Tu) and that the particle measuring device (8) is switched into a safe mode if the measured temperature (T) exceeds the first limit value (To) or falls below the second limit value (Tu).