The present disclosure relates to a method for determining a volumetric and/or mass flow rate of a medium flowing in a tube, wherein a density and/or a viscosity of the fluid is/are determined using a MEMS sensor chip, wherein the medium flowing in the tube at least partially flows through a measuring channel of the MEMS sensor chip to determine the density and/or the viscosity of the fluid, and wherein the volumetric and/or mass flow rate of the medium is determined regardless of the medium based on a detected pressure drop over the measuring channel of the MEMS sensor chip and the density and/or viscosity determined by the MEMS sensor.

A sensor support portion supports a physical quantity sensor. A flow path housing portion forms a measurement flow path, which accommodates a support tip end portion of the sensor support portion. The sensor support portion includes a support front surface, which includes a front fixed portion away from the support tip end portion and fixed to an inner surface of the flow path housing portion. The physical quantity sensor includes a sensor exposure surface exposed from the support front surface. A separation distance between an end portion of the front fixed portion and an end portion of the sensor exposure surface is smaller than a separation distance between the end portion of the sensor exposure surface and the support tip end portion.

A sensor support portion supports a physical quantity sensor. A flow path housing portion forms a measurement flow path, which accommodates a support tip end portion of the sensor support portion. The sensor support portion includes a support front surface, which includes a front fixed portion away from the support tip end portion and fixed to an inner surface of the flow path housing portion. The physical quantity sensor includes a sensor exposure surface exposed from the support front surface. A separation distance between an end portion of the front fixed portion and an end portion of the sensor exposure surface is smaller than a separation distance between the end portion of the sensor exposure surface and the support tip end portion.

The invention relates to a thermal type flow meter, comprising a flow tube for a medium whose flow is to be determined, a sensor tube, having an inlet and an outlet connected to the flow tube, the sensor tube comprising a thermal flow sensor for measuring a temperature differential to determine the flow, a pressure sensor provided at the flow tube to measure the pressure of the flow, a temperature sensor provided at the flow tube to measure the temperature of the flow, characterized by a processing unit for determination of the actual medium properties based on the pressure measured by the pressure sensor, the temperature measured by the temperature sensor and intrinsic medium data and a processing unit for determination of the flow by compensating the measurement of the thermal flow sensor with the actual medium properties and calibration data.

The invention relates to a thermal type flow meter, comprising a flow tube for a medium whose flow is to be determined, a sensor tube, having an inlet and an outlet connected to the flow tube, the sensor tube comprising a thermal flow sensor for measuring a temperature differential to determine the flow, a pressure sensor provided at the flow tube to measure the pressure of the flow, a temperature sensor provided at the flow tube to measure the temperature of the flow, characterized by a processing unit for determination of the actual medium properties based on the pressure measured by the pressure sensor, the temperature measured by the temperature sensor and intrinsic medium data and a processing unit for determination of the flow by compensating the measurement of the thermal flow sensor with the actual medium properties and calibration data.

A sensor recess portion is provided on a sensor back surface. A membrane portion provided with a detection element forms a bottom surface of the sensor recess portion. A sensor support portion includes a back support portion, a support recess portion, a support hole, and a support recess inner wall surface. The back support portion covers an opening of the sensor recess portion. The support recess portion is provided on a side opposite from a physical quantity sensor. The support hole penetrates the back support portion and communicates with the opening. The support recess inner wall surface extends from the support recess bottom portion and is inclined with respect to a center line of the support hole.

A flow rate measurement system outputs a measurement value which represents a magnitude of a flow rate and a flow direction of a fluid that flows through a particular main passage. The system includes a bypass passage disposed in the main passage, a detection unit disposed in the bypass passage that outputs a detection value corresponding to a magnitude of a flow rate and a flow direction of the fluid flowing through the bypass passage, and a calculation unit that, by using the detection value, calculates the measurement value by compensating as needed for a delay in the change in flow rate in the bypass passage with respect to the change in flow rate in the main passage. The compensation is based on whether a change of flow direction has occurred in the main passage or the bypass passage.

A flow meter includes: a flat substrate; a housing that houses the substrate and has an open in at least one surface; a cover that covers the substrate and covers an open surface of the housing; a support that supports the substrate and is in contact with the cover and the substrate; and a fixing unit that connects the substrate and the housing, in which, in a first region and a second region formed by dividing the substrate into two parts at a center in a longitudinal direction, the support is disposed in the first region, and the fixing unit is disposed in the second region.

A physical quantity sensing device is installed to a circuit board and is configured to output a signal, which corresponds to a physical quantity of air flowing through a physical quantity measurement passage. A physical quantity measurement passage inlet, which is communicated with the physical quantity measurement passage, includes a first inner surface and a second inner surface. A second distance, which is measured from the physical quantity sensing device to the second inner surface in a plate thickness direction of the circuit board, is larger than a first distance, which is measured from the circuit board to the first inner surface in the plate thickness direction of the circuit board.

A method for the detection of restricted airflow to a smoke sensor in a central detector unit of an aspirating smoke detection system. An aspirator of the detector unit draws air into the central detector unit along a plurality of sampling pipes. A first portion of the air is directed along a sensing conduit via a filter to the smoke sensor, whilst a second portion of the air continues along a primary conduit and is not directed through the smoke sensor. A first flow meter is positioned on the sensing conduit, and a second flow rate meter is positioned on the primary conduit. A ratio of the flow rates measured by the first and second flow meters is calculated, and used to determine that the filter is restricting airflow to the smoke sensor when the ratio exceeds a predetermined threshold.