Fläktgroup Sweden Ab

Jari Mikkonen

Teuvo Sillanpää

Erkki Seppäläinen

Jari Hokkanen

Timo Lagerstam

Timo Kaasalainen

An apparatus for measuring air flow in a duct includes a sensor fittable into connection with the duct. The sensor includes an ultrasound transmitter, at least two ultrasound receivers, and a control unit to which the ultrasound transmitter and ultrasound receivers are connectable. The apparatus further includes means for measuring temperature. In a method, with the apparatus, the temperature of the air and/or of a sensor in a duct is measured with means for measuring temperature. A sensor calibration measurement at the temperature in question is performed with the apparatus if a calibration of the sensor at the measured temperature and/or within a certain predefined temperature range has not been performed earlier from the environs of the measured temperature, and temperature compensation data for the measurement result of air flow, the data being formed on the basis of calibration measurement, is determined and/or recorded in memory with the apparatus.

Apparatus and method for measuring air flow

In an apparatus and method for measuring air flow in a duct, e.g. in a ventilation duct, the apparatus includes a sensor fittable into connection with the duct at a certain distance from an interference source, the sensor including an ultrasound transmitter and at least two ultrasound receivers, and a control unit to which the ultrasound transmitter and ultrasound receivers are connectable. The control unit is adapted to measure the phase difference of the ultrasound signal received at the same moment in time by at least two ultrasound receivers fitted into connection with the duct and, based on the measured phase difference, to determine the flow velocity and/or flow direction of the air. The control unit is adapted to compensate the determined flow velocity and/or flow direction of the air with a coefficient that is formed on the basis of the diameter of the duct, the type of interference source and the distance between the sensor and the interference source.

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Nokia, Finland

Jari Mikkonen