Abstract: The invention relates to a method and an apparatus for measuring particle concentrations in an aerosol. The apparatus comprises means (103) for driving flow (105) into apparatus (101), means (115) for electrically charging particles (109) to become electrically charged particles (123) by ions (113) produced by a charger, means (117) for removing free ions (113) which are not attached to the electrically charged particles (123), and means (119) for measuring electrical current carried by the electrically charged particles (123). The means (115) for charging the particles and the means (119) for measuring electrical current carried by the electrically charged particles (123) are dimensioned such that the means (119) for measuring electrical current carried by the electrically charged particles (123) only measures a part of a total current carried by the particles.

Abstract: The present invention relates to an apparatus (1) and process for measuring characteristics of a particle flow. The measuring is done with two different cut-off diameters of a particle trap (13) of which one cut-off diameter is adjusted based on the measured particle characteristics.

Abstract: The present invention relates to an apparatus (1) for particle measurement. The apparatus (1) comprising a mixing chamber (16) having a sample inlet (14), an ionized gas outlet (12) for feeding ionized clean gas into the mixing chamber (16), and a mixing chamber outlet (18) for discharging mixed sample aerosol formed in the mixing chamber (16). The apparatus further comprises a sample channel (34) connected to the sample inlet (14) and extending in a first supply direction, a sample supply connection (50) arranged to supply sample aerosol to the sample channel (34) and a sample supply channel (52) connected to the sample supply connection (50) in a second supply direction transverse to the first supply direction. The sample supply connection (50) is arranged to supply the sample aerosol from the sample supply channel (52) to the sample channel (34) as a swirling sample aerosol flow.

Abstract: A new apparatus for monitoring fine particle concentration in an exhaust system of a combustion engine has a part that extends into the exhaust system, and a housing that includes structure that attaches and seals the apparatus to the exhaust system through a single opening in a wall of the exhaust system. A gas inlet in the housing provides a measurement flow into a particle measurement sensor inside the housing. At least a fraction of the particles entering the particle measurement sensor are charged, and at least a fraction of the current carried by the charged particles are detected. A gas outlet in the housing carries the measurement flow away from the particle measurement sensor. The structure that attaches the apparatus to the exhaust system has one electrical connector that provides power to the sensor, and another electrical connector that transmits the electrical signal created by the sensor.

Abstract: The present invention relates to an apparatus (1) for monitoring particles in a channel (11) or a space comprising aerosol and to an ion trap arrangement in the apparatus. The apparatus (1) comprises an ejector (24), gas supply (6, 16, 18, 19) arranged to feed an essentially particle free ionized gas flow (C) to the ejector (24), a sample-inlet arrangement (2) arranged to provide a sample aerosol flow (A) from the channel (11) into the ejector (24) by means of suction provided by the gas supply (6, 16, 18, 19) and the ejector (24) for charging at least a fraction of the particles of the sample aerosol flow (A), and an ion trap (12) extending at least partly into ejector (24) for removing ions not attached to the particles. According to the invention the ion trap (12) is a provided as a metal trap wire.

Abstract: Apparatus (1) for generating acknowledged flow (Q), comprising a first passage (2) with ends (3,4) for acknowledged flow (Q) inlet and outlet, a discharge electrode (5) for generating airborne unipolar ions (8) positioned inside the first passage (2), a counter electrode (6) adapted to attract said airborne ions (8), thereby being adapted to cause a net flow (7) of airborne ions (8) and thereby generating an airflow (Q) in the direction of the net flow of airborne ions (8), sensing element (12, 13), the output of which is a function of the concentration of the airborne electric charge (8, 11), means (17) for switching or modulating a parameter which affects the output of the sensing element (12,13) and means for determining the volumetric flow (Q) on the basis of the time response which switching or modulation creates to the sensing element (12,13) output. 11. Use of apparatus (1) as described in the previous claims for determining ultrafine particle concentration. Process for generating acknowledged flow.

Abstract: A process for measuring particle concentrations in a gas using an ejector for producing an essentially constant sample flow and for efficient mixing of the particle-containing sample and essentially clean, ionized gas. The invention also relates to an apparatus implementing such process. The process and the apparatus can be utilized for example in measuring particle concentrations in an exhaust system of a combustion engine.

Abstract: The present invention relates to an apparatus (1) for monitoring particles in a channel (11) or a space comprising aerosol and to an ion trap arrangement in the apparatus. The apparatus (1) comprises an ejector (24), gas supply (6, 16, 18, 19) arranged to feed an essentially particle free ionized gas flow (C) to the ejector (24), a sample-inlet arrangement (2) arranged to provide a sample aerosol flow (A) from the channel (11) into the ejector (24) by means of suction provided by the gas supply (6, 16, 18, 19) and the ejector (24) for charging at least a fraction of the particles of the sample aerosol flow (A), and an ion trap (12) extending at least partly into ejector (24) for removing ions not attached to the particles. According to the invention the ion trap (12) is a provided as a metal trap wire.

Abstract: A new apparatus for monitoring fine particle concentration in an exhaust system of a combustion engine has a part that extends into the exhaust system, and a housing that includes structure that attaches and seals the apparatus to the exhaust system through a single opening in a wall of the exhaust system. A gas inlet in the housing provides a measurement flow into a particle measurement sensor inside the housing. At least a fraction of the particles entering the particle measurement sensor are charged, and at least a fraction of the current carried by the charged particles are detected. A gas outlet in the housing carries the measurement flow away from the particle measurement sensor. The structure that attaches the apparatus to the exhaust system has one electrical connector that provides power to the sensor, and another electrical connector that transmits the electrical signal created by the sensor.