Abstract: A process dilutes an aerosol by feeding an input aerosol through an inlet pipe surrounded by an annular space to a first mixing stage. An output aerosol leaves purified via an outlet as a particle-free clean gas. The particle-free clean gas is fed to the annular space upstream of the outlet and is mixed with the aerosol. A mixing stage includes an inlet pipe feeding aerosol as inlet aerosol. A downstream purification device purifies outlet aerosol leaving the mixing stage via an outlet pipe to form the particle-free clean gas. A mass flow controller and a pump suction off the outlet aerosol from the outlet pipe. A return line, for the clean gas, leads upstream into the annular space.

Abstract: A device for condensing vapor on condensation nuclei, especially for a particle counter, includes an inlet, via which a gas stream carrying particles as condensation nuclei enters into a feed channel; with a saturation channel. An evaporation unit extends over at least a part of the saturation channel. In the evaporation unit a working liquid can be evaporated in the saturation channel. An outlet leads to a measuring unit. At least one flow passage is provided from the feed channel towards the saturation channel. The at least one flow channel is directed at an angle greater than 90° in relation to a direction in which the feed channel extends.

Abstract: A device dilutes an aerosol without distortion due to loss of particles, especially liquid particles, on wall surfaces. An inlet pipe feeds aerosol as inlet aerosol and an outlet pipe has an inlet opening arranged at a finite distance from an outlet end of the inlet pipe. An annular space surrounds an end area of the inlet pipe. A clean gas line opens, via an outlet opening, into the annular space. A process is provided including feeding the aerosol as inlet aerosol through the inlet pipe, with particle-free clean gas fed to an end area of the inlet pipe and mixed with the fed inlet aerosol into a diluted outlet aerosol. The diluted outlet aerosol is sent to a measuring device. The mass flow of the aerosol sent to the measuring device and that of the added clean gas are maintained at a fixed ratio.

Abstract: A process dilutes an aerosol by feeding an input aerosol through an inlet pipe surrounded by an annular space to a first mixing stage. An output aerosol leaves purified via an outlet as a particle-free clean gas. The particle-free clean gas is fed to the annular space upstream of the outlet and is mixed with the aerosol. A mixing stage includes an inlet pipe feeding aerosol as inlet aerosol. A downstream purification device purifies outlet aerosol leaving the mixing stage via an outlet pipe to form the particle-free clean gas. A mass flow controller and a pump suction off the outlet aerosol from the outlet pipe. A return line, for the clean gas, leads upstream into the annular space.

Abstract: A device for condensing vapor on condensation nuclei, especially for a particle counter, includes an inlet, via which a gas stream carrying particles as condensation nuclei enters into a feed channel; with a saturation channel. An evaporation unit extends over at least a part of the saturation channel. In the evaporation unit a working liquid can be evaporated in the saturation channel. An outlet leads to a measuring unit. At least one flow passage is provided from the feed channel towards the saturation channel. The at least one flow channel is directed at an angle greater than 90° in relation to a direction in which the feed channel extends.

Abstract: A method for detecting decalibration of a device for analyzing particles, including irradiating particles with light, detecting light scattered from the particles, amplifying, digitizing and detecting the electric signal obtained in a plurality of digital channels corresponding to the intensity representing the particle size and monitoring the appearance of the Mie peak in the measured size-dependent frequency distribution and sending a report if the Mie peak deviates in a digital channel other than the digital standard channel belonging to it based on measurement settings. The electronic analyzing unit detecting a Mie peak in the measured particle size distribution and assigning it to a digital detection channel in a device for detecting the concentration of small particles in gas, with a sample tube, a light source, a detector detecting scattered light scattered on the particles, an analog amplifier, an analog-digital converter, an electronic analyzing unit and a display and operating unit.

Abstract: A method for detecting decalibration of a device for analyzing particles, including irradiating particles with light, detecting light scattered from the particles, amplifying, digitizing and detecting the electric signal obtained in a plurality of digital channels corresponding to the intensity representing the particle size and monitoring the appearance of the Mie peak in the measured size-dependent frequency distribution and sending a report if the Mie peak deviates in a digital channel other than the digital standard channel belonging to it based on measurement settings. The electronic analyzing unit detecting a Mie peak in the measured particle size distribution and assigning it to a digital detection channel in a device for detecting the concentration of small particles in gas, with a sample tube, a light source, a detector detecting scattered light scattered on the particles, an analog amplifier, an analog-digital converter, an electronic analyzing unit and a display and operating unit.

Abstract: For the reliable condensation of steam on condensation nuclei in an aerosol flow and therefore for enlarging the particles in the aerosol, the invention provides a method which is characterized in that condensation nuclei are passed through an inner area of an evaporating zone forming a flow area, the liquid to be evaporated is contacted with the flow area and evaporated therein and the thus produced steam is condensed on the condensation nuclei. the invention also provides an apparatus for condensing steam on condensation nuclei with an inlet for condensation nuclei and an evaporating zone constructed in such a way that a flow area for the condensation nuclei has a heated liquid duct open thereto and that a condensation flue is connected to the flow area. The invention also provides methods and apparatuses for counting particles, for producing monodisperse aerosols using the aforementioned method or the aforementioned apparatus.

Abstract: For the reliable condensation of steam on condensation nuclei in an aerosol flow and therefore for enlarging the particles in the aerosol, the invention provides a method which is characterized in that condensation nuclei are passed through an inner area of an evaporating zone forming a flow area, the liquid to be evaporated is contacted with the flow area and evaporated therein and the thus produced steam is condensed on the condensation nuclei. The invention also provides an apparatus for condensing steam on condensation nuclei with an inlet for condensation nuclei and an evaporating zone constructed in such a way that a flow area for the condensation nuclei has a heated liquid duct open thereto and that a condensation flue is connected to the flow area. The invention also provides methods and apparatuses for counting particles, for producing monodisperse aerosols using the aforementioned method or the aforementioned apparatus.

Abstract: For the reliable condensation of steam on condensation nuclei in an aerosol flow and therefore for enlarging the particles in the aerosol, the invention provides a method which is characterized in that condensation nuclei are passed through an inner area of an evaporating zone forming a flow area, the liquid to be evaporated is contacted with the flow area and evaporated therein and the thus produced steam is condensed on the condensation nuclei. the invention also provides an apparatus for condensing steam on condensation nuclei with an inlet for condensation nuclei and an evaporating zone constructed in such a way that a flow area for the condensation nuclei has a heated liquid duct open thereto and that a condensation flue is connected to the flow area. The invention also provides methods and apparatuses for counting particles, for producing monodisperse aerosols using the aforementioned method or the aforementioned apparatus.

Abstract: A method for measuring the characteristics of particles in a fluid by detecting electromagnetic radiation scattered on individual particles and an apparatus for performing the method are characterized in that the measurement takes place in structurally separated manner using at least one irradiating device and at least one receiver device in at least one sensor arrangement through which flows a fluid flow containing the particles to be measured, that in the at least one sensor arrangement signal formation takes place of a signal to be received in the receiver device using exclusively optomechanical elements and that signals are transmitted between the at least one sensor arrangement and the at least one irradiating device or the at least one receiver device by means of optical signal transmitters. This makes the apparatus particularly suitable for use in explosion-endangered environments and at difficultly accessible measurement locations, e.g. on chimneys.