Abstract: The object of this invention is a ventilation duct unit (1), which comprises an inlet (2), an outlet (3), a flow channel (4), which extends from the inlet to the outlet, and which is delimited by a wall (5) between the inlet and the outlet, a closing part (6), which is arranged into the flow channel, and which in open position enables flow in the flow channel, and in closed position prevents flow in the flow channel, closing member (12), which as a response to detecting fire, sets the closing part (6) to a predetermined position, and an actuator (8), which moves the closing part (6) between open and closed state in order to achieve flow defined for the actuator (8) in the flow channel.

Abstract: The object of this invention is a ventilation duct unit (1), which comprises an inlet (2), an outlet (3), a flow channel (4), which extends from the inlet to the outlet, and which is delimited by a wall (5) between the inlet and the outlet, a closing part (6), which is arranged into the flow channel, and which in open position enables flow in the flow channel (4), and in closed position prevents flow in the flow channel, and a closing member (12), which as a response to detecting fire, sets the closing part (6) to a predetermined position.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An apparatus and method for measuring air flow in a duct, e.g. in a ventilation duct, includes a sensor fittable into connection with the duct, 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, during the measuring of air flow, the phase difference of an 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 apparatus is adapted to perform a calibration of the apparatus by transmitting with an ultrasound transmitter at least one calibration signal and by receiving the calibration signal with at least two ultrasound receivers.