Abstract: The aerosol diluting apparatus includes a first diluting unit to provide a first modified sample flow by combining an aerosol sample flow with a first diluting gas flow, an ejector unit to draw the first modified sample flow from the first diluting unit to the ejector unit and to provide a second modified sample flow by mixing a second dilution gas flow with the first modified sample flow, a control unit, and a control valve, wherein the control unit and the control valve are arranged to adjust flow rate of the second dilution gas flow according to an inlet pressure of the aerosol sample flow, so as to keep the dilution factor of the diluting apparatus substantially independent of the inlet pressure.

Abstract: An apparatus for measuring aerosol particles includes a charging unit to form charged particles by charging particles of an aerosol sample flow by diffusion charging, and a collecting unit to provide an electric current by collecting charges from the charged particles by diffusion of the charged particles, the electric current being indicative of number density of aerosol particles of the aerosol sample flow. The internal pressure of the collecting unit is maintained at a reduced value in order to provide a flat response of the electric current for detecting nanoparticles of different sizes.

Abstract: The aerosol diluting apparatus includes a first diluting unit to provide a first modified sample flow by combining an aerosol sample flow with a first diluting gas flow, an ejector unit to draw the first modified sample flow from the first diluting unit to the ejector unit and to provide a second modified sample flow by mixing a second dilution gas flow with the first modified sample flow, a control unit, and a control valve, wherein the control unit and the control valve are arranged to adjust flow rate of the second dilution gas flow according to an inlet pressure of the aerosol sample flow, so as to keep the dilution factor of the diluting apparatus substantially independent of the inlet pressure.

Abstract: A particle measuring apparatus includes a charging unit to form charged particles from aerosol particles carried by an input flow, and a particle detector to provide an electric current by collecting the charged particles, wherein the charging unit in turn includes a counter-electrode having a substantially hemispherical inner portion to define a charging space, an inlet channel for guiding aerosol particles into the charging space, a corona electrode to form charged particles from the aerosol particles by generating a corona discharge in the charging space, and an outlet channel for guiding charged particles from the charging space to the detector.

Abstract: A particle measuring apparatus includes a distributor unit arranged to provide a first partial flow and a second partial flow by separating the second partial flow from an input flow, a particle collecting unit to collect particles from the first partial flow by using a first filter, and a particle monitoring unit to form charged particles by charging particles carried by the second partial flow, and to provide an electric current by collecting the charged particles.

Abstract: A particle measuring apparatus includes a distributor unit arranged to provide a first partial flow and a second partial flow by separating the second partial flow from an input flow, a particle collecting unit to collect particles from the first partial flow by using a first filter, and a particle monitoring unit to form charged particles by charging particles carried by the second partial flow, and to provide an electric current by collecting the charged particles.

Abstract: A method and apparatus for increasing the size of small particles for a condensation particle counter, in which method a particle containing aerosol flow is divided into a sample flow and a sheath flow. The sheath flow is filtered, saturated with vapor and formed to a vortex flow in a saturator which vortex-flow continues in a condenser. The sample flow is introduced to the center of the vortex flow of the saturated sheath flow in the condenser for causing the vapor in the saturated sheath flow to condense on the particles in the sample flow thus increasing the size of the particles.

Abstract: A device and a method for diluting a sample are disclosed. A sample is first diluted by a porous tube type diluter configuration. Then the diluted flow is further diluted by a ejector type diluter configuration. Further a heat exchange based on serrature heat exchange elements inside said porous tube type diluter configuration is disclosed.

Abstract: A method and apparatus for increasing the size of small particles for a condensation particle counter, in which method a particle containing aerosol flow is divided into a sample flow and a sheath flow. The sheath flow is filtered, saturated with vapor and formed to a vortex flow in a saturator which vortex-flow continues in a condenser. The sample flow is introduced to the centre of the vortex flow of the saturated sheath flow in the condenser for causing the vapor in the saturated sheath flow to condense on the particles in the sample flow thus increasing the size of the particles.

Abstract: A method and a sensor device for determining particle emissions from exhaust gases of a combustion engine substantially during the use in an exhaust pipe system or a corresponding exhaust gas duct, in which method emitted particles contained in the exhaust gases are charged and the particle emissions are determined by measuring the electric charge carried by the emitted particles in the exhaust gas duct. The emitted particles are charged by varying the way of charging or the charging power with respect to time in such a manner that as a result of the charging, emitted particles brought into at least two different electrical charge states are present, wherein the charge of the emitted particles is further determined as a difference value/values measured from the emitted particles brought into said at least two different electrical charge states.

Abstract: The invention relates to a measuring device for measuring aerosols, which measuring device comprises detection means (13), means (41) for conveying a signal from the detection means (13), a first insulation (43), a second insulation (44), and a supporting means (42). The first insulation (43) insulates the medium (41) from the supporting means (42), and the second insulation (44) insulates the detection means (13) from the supporting means (42). Also, the second insulation (44) is designed in such a way that it positions the detection means (13) in a predetermined location.

Abstract: An impactor, a frame part for an impactor, a part to be used in an impactor, and a method for processing elements belonging to the impactor. Different elements belonging to different stages of the impactor are coupled to each other with a connecting element in such a way that they can be inserted in the frame part of the impactor, removed from it, or processed, as a single unit.

Abstract: The invention relates to a device (30) for determining the size distribution of aerosol particles from a flow (11), the device (30) comprising an electric mobility analyzer (10) and an impactor (20), connected to each other in such a way that the nozzle part (22a) of the first stage of the impactor (20) is simultaneously the bottom plate of said mobility analyzer (10).

Abstract: A method and a device for measuring density properies of a particle distribution, in which method a first parameter relating to the particle distribution is measured at a first measuring point (302), at least part of the flow that passed through the first measuring point is guided to the second measuring point (304), a second parameter relating to the particle distribution is measured at a second measuring point (305), and said first and second parameters relating to the particle distribution are used to determine at least one density property of the particle distribution of the original flow (306).

Abstract: A method and a sensor device for determining particle emissions from exhaust gases of a combustion engine substantially during the use in an exhaust pipe system or a corresponding exhaust gas duct, in which method emitted particles contained in the exhaust gases are charged and the particle emissions are determined by measuring the electric charge carried by the emitted particles in the exhaust gas duct. The emitted particles are charged by varying the way of charging or the charging power with respect to time in such a manner that as a result of the charging, emitted particles brought into at least two different electrical charge states are present, wherein the charge of the emitted particles is further determined as a difference value/values measured from the emitted particles brought into said at least two different electrical charge states.

Abstract: A method and a device for measuring properties of a particle distribution, in which a parameter relating to the mobility of the particles is measured at one measuring point (302) and a parameter relating to the aerodynamic size of the particles is measured at a second measuring point (305). By means of the measured parameters, at least one property of the particle distribution of the original flow is determined (306).

Abstract: The subject of the invention is a method for minimizing Coulombic losses in impactors and an impactor, in which Coulombic losses have been minimized. The method according to the invention is based on restricting the force effect of the charges accumulated in impactor's insulators on the charged particles. This restriction of the force effect can be realized, for example, by placing an electrically conductive surface between the insulator and the flow, or by forming an insulator so that the force effect is minimized.