A physical quantity measurement device that measures a physical quantity of a fluid has an inflow port and an outflow port, and includes a passage flow channel, a branch flow channel, and a physical quantity detector. An inner peripheral surface of the passage flow channel extends over a pair of facing surfaces, which face each other across the flow passage boundary portion and the inflow port on an upstream side of the flow channel boundary portion. The inner peripheral surface further includes an inflow step surface which forms a step facing the inflow port side.

A heating system includes at least one electric heater disposed within a fluid flow system and a control device that is configured to determine a temperature of the at least one electric heater based on a model, at least one fluid flow system input, and at least one heater input. The at least one heater input includes at least one physical characteristic of the heating system, the at least one physical characteristic includes at least one of a resistance wire diameter, a heater insulation thickness, a heater sheath thickness, a conductivity, a specific heat and density of the material of the heater, an emissivity of the heater and the fluid flow pathway, and combinations thereof. The control device is configured to provide power to the at least one electric heater based on the temperature of the at least one electric heater.

A heating system includes at least one electric heater disposed within a fluid flow system and a control device that is configured to determine a temperature of the at least one electric heater based on a model, at least one fluid flow system input, and at least one heater input. The at least one heater input includes at least one physical characteristic of the heating system, the at least one physical characteristic includes at least one of a resistance wire diameter, a heater insulation thickness, a heater sheath thickness, a conductivity, a specific heat and density of the material of the heater, an emissivity of the heater and the fluid flow pathway, and combinations thereof. The control device is configured to provide power to the at least one electric heater based on the temperature of the at least one electric heater.

A method is provided for measuring different flow properties of a fluid. The method includes (a) providing a nanowire, the resistance of the nanowire varying based on temperature changes of the nanowire that reflect values of the different flow properties of the fluid when the nanowire is operated in different modes of operation respectively, such that the nanowire measures different flow properties when operated in different modes of operation respectively, and (b) alternating the nanowire between different modes of operation, measuring different flow properties of the fluid during the different modes of operation, respectively, and using the measurements of one of the flow properties to correct the measurements of another flow property. Other applications are also described.

A method is provided for measuring different flow properties of a fluid. The method includes (a) providing a nanowire, the resistance of the nanowire varying based on temperature changes of the nanowire that reflect values of the different flow properties of the fluid when the nanowire is operated in different modes of operation respectively, such that the nanowire measures different flow properties when operated in different modes of operation respectively, and (b) alternating the nanowire between different modes of operation, measuring different flow properties of the fluid during the different modes of operation, respectively, and using the measurements of one of the flow properties to correct the measurements of another flow property. Other applications are also described.

The invention relates to a spirometer (1) comprising a MEMS-based thermal fluid flow sensor (13, 13.1, 13.2) for generating a signal in response to a fluid flow generated during inhalation or exhalation; and a microcontroller (14) for calculating the fluid flow from the signal generated by the flow sensor (13, 13.1, 13.2). The spirometer (1) may be connected to other devices, such as a smartphone or a personal computer or any other computing unit which is adapted to collect, store, analyse, exchange and/or display data. The invention further describes the use of the spirometer (1) in measuring a user's lung performance and/or monitoring it over time. Furthermore, the spirometer (1) may be provided in a system together with an air quality measurement device for determining the air quality at a location of interest; and a computing unit for collecting, analysing and correlating the user's lung performance data obtained from the spirometer (1) with the air quality data, and optionally geolocalisation data of said location.

A gas separator for separating a multiphase medium containing a gas and a liquid includes a tubular basic unit having a longitudinal axis, an intake for a gaseous medium, a liquid outlet and a gas outlet. The tubular basic unit has an intake region and a discharge region. The gas separator includes, between the intake region and the discharge region, a weir having a guiding surface, over which the medium can flow to form a shallow water region. The gas contained in the medium can escape from the medium in the shallow water region and be led away from the gas separator through the gas outlet. The disclosure is also directed to an apparatus for registering flow of at least one component of a multiphase medium.

A gas separator for separating a multiphase medium containing a gas and a liquid includes a tubular basic unit having a longitudinal axis, an intake for a gaseous medium, a liquid outlet and a gas outlet. The tubular basic unit has an intake region and a discharge region. The gas separator includes, between the intake region and the discharge region, a weir having a guiding surface, over which the medium can flow to form a shallow water region. The gas contained in the medium can escape from the medium in the shallow water region and be led away from the gas separator through the gas outlet. The disclosure is also directed to an apparatus for registering flow of at least one component of a multiphase medium.

Methods for determining phase fractions of a downhole fluid via thermal properties of the fluids are provided. In one embodiment, a method includes measuring a temperature of a fluid flowing through a completion string downhole in a well and heating a resistive element of a thermal detector at a position along the completion string downhole in the well by applying power to the resistive element such that heat from the resistive element is transmitted to the fluid flowing by the position. The method also includes determining, via the thermal detector, a flow velocity of the fluid through the completion string and multiple thermal properties of the fluid, and using the determined flow velocity and the multiple thermal properties to determine phase fractions of the fluid. Additional systems, devices, and methods are also disclosed.

Methods for determining phase fractions of a downhole fluid via thermal properties of the fluids are provided. In one embodiment, a method includes measuring a temperature of a fluid flowing through a completion string downhole in a well and heating a resistive element of a thermal detector at a position along the completion string downhole in the well by applying power to the resistive element such that heat from the resistive element is transmitted to the fluid flowing by the position. The method also includes determining, via the thermal detector, a flow velocity of the fluid through the completion string and multiple thermal properties of the fluid, and using the determined flow velocity and the multiple thermal properties to determine phase fractions of the fluid. Additional systems, devices, and methods are also disclosed.