Abstract: A flow measurement system includes an ultrasonic flowmeter including two or more ultrasonic transducers arranged in flow direction, when the ultrasonic flowmeter is fixed to the channel, and emitting and receiving an ultrasonic pulse in the channel, and a processor connected to the transducers. The processor determines and stores transit times of ultrasonic pulses propagating in and against a flow direction along a path in the channel, and determines a flow of gas using the transit times. The flow measurement system further includes a damper system has a damper blade arranged in the channel downstream of the ultrasonic flowmeter. The ultrasonic transducers receive one or more reflections of an ultrasonic pulse in the channel, and the processor determines and stores transit times of ultrasonic pulses propagating in and against flow direction along one or more reflection paths, and determines the flow of gas using the transit times.

Abstract: An HVAC flow measurement system (1) comprises an ultrasonic flowmeter (10) for measuring a flow of gas through a channel (2). The ultrasonic flowmeter (10) comprises ultrasonic transducers (11, 12) arranged at a distance from each other in flow direction (f). The ultrasonic transducers (11, 12) are configured to emit an ultrasonic pulse into the channel (2) and to receive an ultrasonic pulse in the channel (2). The flow measurement system (1) further comprises a processor (100) connected to the two ultrasonic transducers (11, 11a, 11b, 12, 12a, 12b) and configured to determine and store transit times of ultrasonic pulses propagating in and against flow direction (f) along more than one path (R1, R2) in the channel (2), and to determine the flow of gas using the transit times.

Abstract: An HVAC flow measurement system (1) comprises an ultrasonic flowmeter (2) for measuring a flow of gas through a channel (3). The ultrasonic flowmeter (2) comprises ultrasonic transducers (20, 21) arranged at a distance L from each other in flow direction f. The ultrasonic transducers (20, 21) are configured to emit an ultrasonic pulse into the channel (3) and to receive an ultrasonic pulse in the channel (3). The flowmeter (2) further comprises a processor (200) connected to the two ultrasonic transducers (20, 21) and configured to measure transit times in such a manner that a flow velocity of the fluid and at least one characteristic parameter(s) of the channel (30) are determined by using the transit times.

Abstract: An HVAC flow measurement system (1) comprises an ultrasonic flowmeter (10) for measuring a flow of gas through a channel (2). The ultrasonic flowmeter (10) comprises ultrasonic s transducers (11, 12) arranged at a distance from each other in flow direction (f) and configured to emit an ultrasonic pulse into the channel (2) and to receive an ultrasonic pulse in the channel (2). The flow measurement system (1) further comprises a processor (100) connected to the two ultrasonic transducers (11, 11a, 11b, 12, 12a, 12b) and configured to determine and store transit times of ultrasonic pulses propagating in and against flow direction (f) along one or more than one path (R1, R2) in the channel (2), and to determine the flow of gas using the transit times. A damper system (40) having a damper blade (4) arranged in the channel (2) is provided downstream of the ultrasonic flowmeter (10).

Abstract: A method for self-diagnosing an ultrasonic flowmeter assembly (I) comprising at least one ultrasonic transducer (20, 21) fixed to the conduit section (3) and configured to emit ultrasonic pulses into the conduit (3) and to receive ultrasonic pulses after having travelled along at least one path (R, I) in the conduit section (3) and to output measurement data, further comprising a controller (200) for processing the measurement data, wherein a reference measurement and test measurement each comprises emitting and receiving at least one ultrasonic pulse along at least one same or comparable path (R). The method comprises: (a) providing a reference measurement data; (b) obtaining a test measurement data; (c) comparing the reference and test measurement data, wherein the reference measurement data (A) comprises an ultrasonic reference signal characteristic (51,61), and the test measurement data (B) comprises an ultrasonic test signal characteristic (52, 62).

Abstract: A method for predictive maintenance of an ultrasonic sensor in an HVAC system, the ultrasonic sensor including one or more ultrasonic transducers that measure ultrasonic signals as a function of time during an operation of the HVAC system, and produce raw electronic signals as a function of time, the method including the method elements of extracting a signal parameter from the raw electronic signals; creating a set of data including the signal parameter as a function of time; selecting one or more limit parameters; and estimating a time limit based on the set of data. The time limit is a time when the signal parameter is predicted to reach the limit parameter.

Abstract: An HVAC flow measurement system (1) comprises an ultrasonic flowmeter (2) for measuring a flow of gas through a channel (3). The ultrasonic flowmeter (2) comprises ultrasonic transducers (20, 21) arranged at a distance L from each other in flow direction f. The ultrasonic transducers (20, 21) are configured to emit an ultrasonic pulse into the channel (3) and to receive an ultrasonic pulse in the channel (3). The flowmeter (2) further comprises a processor (200) connected to the two ultrasonic transducers (20, 21) and configured to measure transit times in such a manner that a flow velocity of the fluid and at least one characteristic parameter(s) of the channel (30) are determined by using the transit times.

Abstract: An air treatment device is disclosed. The air treatment device includes an air duct configured to deliver an air flow. A first filter stage is included and comprises at least one air filter arranged in the air duct for filtering the air flow. At least a second filter stage is also included and comprises at least one further air filter and is arranged downstream of the first filter stage (for filtering the air flow after having passed the first filter stage. The second filter stage is controllable between at least two states with different filtration efficiencies, whereby, with respect to a filtration efficiency in the first state, a filtration efficiency in the second state is lower, in particular the filtration efficiency in the second state is essentially zero. An air quality sensor is also present, the sensor allowing for measuring the air quality of the air flow in between the first and the second air filter stages.

Abstract: A method of detecting an operating condition of a controllable flow regulator in a fluid flow channel of an HVAC system, comprising transmitting a sonic signal, from a sonic transmitter, directly or indirectly to the flow regulator, the sonic signal being distinguished from background noise by being at least one of: (i) modulated according to a modulation schema, (ii) an ultrasonic signal, (iii) a frequency selected to be away from background noise, receiving a signal from a sonic receiver for detecting the transmitted signal after interacting with the flow regulator; and determining, in an electronic signal processor, the operating condition of the flow regulator on the basis of the signal received.

Abstract: An air treatment device is disclosed. The air treatment device includes an air duct configured to deliver an air flow. A first filter stage is included and comprises at least one air filter arranged in the air duct for filtering the air flow. At least a second filter stage is also included and comprises at least one further air filter and is arranged downstream of the first filter stage (for filtering the air flow after having passed the first filter stage. The second filter stage is controllable between at least two states with different filtration efficiencies, whereby, with respect to a filtration efficiency in the first state, a filtration efficiency in the second state is lower, in particular the filtration efficiency in the second state is essentially zero. An air quality sensor is also present, the sensor allowing for measuring the air quality of the air flow in between the first and the second air filter stages.

Abstract: The invention relates to a method and a system for producing a hydrocarbon- and hydrogen-containing gas mixture from plastics, and the use of the system for producing this gas mixture and the use of this gas mixture as a starting material in chemical syntheses or for gas supply.

Abstract: An HVAC flow measurement system (a) comprises an ultrasonic flowmeter (2) for measuring a flow of gas through a channel (3). The ultrasonic flowmeter (2) comprises ultrasonic transducers (20, 21) arranged at a distance L from each other in flow direction f. The ultrasonic transducers (20, 21) are configured to emit an ultrasonic pulse into the channel (3) and to receive an ultrasonic pulse in the channel (3). The flowmeter (2) further comprises a processor (200) connected to the two ultrasonic transducers (20, 21) and configured to measure transit times in such a manner that a flow velocity of the fluid and at least one characteristic parameter(s) of the channel (30) are determined by using the transit times.

Abstract: An HVAC flow measurement system (1) comprises an ultrasonic flowmeter (10) for measuring a flow of gas through a channel (2). The ultrasonic flowmeter (10) comprises ultrasonic s transducers (11, 12) arranged at a distance from each other in flow direction (f) and configured to emit an ultrasonic pulse into the channel (2) and to receive an ultrasonic pulse in the channel (2). The flow measurement system (1) further comprises a processor (100) connected to the two ultrasonic transducers (11, 11a, 11b, 12, 12a, 12b) and configured to determine and store transit times of ultrasonic pulses propagating in and against flow direction (f) along one or more than one path (R1, R2) in the channel (2), and to determine the flow of gas using the transit times. A damper system (40) having a damper blade (4) arranged in the channel (2) is provided downstream of the ultrasonic flowmeter (10).

Abstract: An HVAC flow measurement system (1) comprises an ultrasonic flowmeter (10) for measuring a flow of gas through a channel (2). The ultrasonic flowmeter (10) comprises ultrasonic transducers (11, 12) arranged at a distance from each other in flow direction (f). The ultrasonic transducers (11, 12) are configured to emit an ultrasonic pulse into the channel (2) and to receive an ultrasonic pulse in the channel (2). The flow measurement system (1) further comprises a processor (100) connected to the two ultrasonic transducers (11, 11a, 11b, 12, 12a, 12b) and configured to determine and store transit times of ultrasonic pulses propagating in and against flow direction (f) along more than one path (R1, R2) in the channel (2), and to determine the flow of gas using the transit times.