To obtain a physical quantity detection device capable of reducing an intake amount of air accompanied by foreign matter. A physical quantity detection device (20) of the invention includes a housing arranged in a main passage through which a measurement target gas (2) flows. The housing is provided with a second sub-passage (B) that takes in a part of the measurement target gas (2) flowing in the main passage, a circuit chamber (135) that accommodates a pressure sensor (320) that detects a pressure of the measurement target gas (2), and a pressure introduction passage (170) having one end opened in the middle of the second sub-passage (B) and the other end opened in the circuit chamber (135) and capable of introducing the pressure of the measurement target gas (2) from the second sub-passage (B) into the circuit chamber (135). In the pressure introduction passage (170), an introduction port (171) is arranged at a position offset outward from a side wall surface (152b) of the second sub-passage (B).

A flow rate detector includes: a housing; and a substrate assembly disposed in the housing. The substrate assembly has a flow rate detection element, a temperature detection element, and a circuit board on which the flow rate detection element and the temperature detection element are mounted. The circuit board includes a body portion fixed to the housing, and a protrusion extended to protrude from the body portion. The protrusion has an element fix portion to which the temperature detection element is fixed. The protrusion has a supported portion within a supported range including a position of the element fix portion. The supported range is defined from the element fix portion to a tip end of the protrusion along an extension direction of the protrusion. The supported portion is supported by the housing to suppress a displacement of the element fix portion in a thickness direction of the circuit board.

A flow measurement apparatus can include a main flow passage, a variable flow restrictor, a bypass flow passage having an inlet connected with the main flow passage upstream of the variable flow restrictor and an outlet connected with the main flow passage downstream of the variable flow restrictor, and a mass flowmeter connected in the bypass flow passage between the inlet and the outlet. A method can include connecting a flow measurement apparatus, so that a fluid flow in a well also flows through the flow measurement apparatus, and varying a restriction to the fluid flow through the variable flow restrictor in response to a change in a flow rate of the fluid flow.

A system includes a flow tube configured to receive a flow measured by an ultrasonic flow measurement, wherein a center region of the flow tube is configured to have a drop in pressure. The system also includes a heat source/hot wire and temperature sensors configured to enable a flow measured by a thermal massflow measurement. In the system, a controller is configured to compare the flow measured by the ultrasonic flow measurement to the flow measured by the thermal massflow measurement. The controller determines a ratio of the flow measured by an ultrasonic flow measurement to the flow measured on by the flow measurement based on thermal massflow. The controller also calculates a density, a thermal conductivity and an energy and/or gas content of the gas.

A device for the measurement of a flow rate of a gas in a main gas piping includes: a first branch configured for the diversion of a portion of a gas flow in transit in the main piping towards a measuring component; the measuring component including an inlet mouth, connected to the first branch, and an outlet mouth, the measuring component being configured for the direct measurement of the flow rate of the portion of gas flow, diverted by the main piping, which crosses the same measuring component; and a second branch connected to the outlet mouth and configured for the re-introduction into the main piping of the diverted portion of gas flow crossing the measuring component.

A device for the measurement of a flow rate of a gas in a main gas piping includes: a first branch configured for the diversion of a portion of a gas flow in transit in the main piping towards a measuring component; the measuring component including an inlet mouth, connected to the first branch, and an outlet mouth, the measuring component being configured for the direct measurement of the flow rate of the portion of gas flow, diverted by the main piping, which crosses the same measuring component; and a second branch connected to the outlet mouth and configured for the re-introduction into the main piping of the diverted portion of gas flow crossing the measuring component.

A fluid sensing apparatus is provided having a fluid flow channel having a flow restriction. A fluid sensor is in fluid communication with first and second fluid ports, and a laminar flow element. The laminar flow element includes a flow stabilisation rod which defines a fluid sensing portion of the fluid flow channel. The flow restriction comprises a reduction in the hydraulic diameter of the fluid sensing portion of the fluid flow channel which is caused by a decrease in diameter of the fluid flow channel, or by an increase in the diameter of the flow stabilisation rod, or by both a decrease in diameter of the fluid flow channel and an increase in the diameter of the flow stabilisation rod. Also provided is a mass flow controller including such a fluid sensing apparatus.

A physical quantity measurement device includes a housing forming a measurement flow path in which a sensor support supports a physical quantity sensor. The measurement flow path includes a sensor path in which the physical quantity sensor is disposed, an upstream curved path between the sensor path and an inlet, and a downstream curved path between the sensor path and an outlet. The housing includes a measurement narrowed portion that gradually narrows the measurement flow path in a direction from the inlet toward the physical quantity sensor. An upstream end of the sensor support is provided upstream of the measurement narrowed portion in an arrangement cross section along an imaginary straight line passing through the physical quantity sensor and extending in an arrangement direction in which the upstream curved path and the downstream curved path are arranged.

A physical quantity measurement device includes a housing forming a measurement flow path in which a sensor support supports a physical quantity sensor. The measurement flow path includes a sensor path in which the physical quantity sensor is disposed, an upstream curved path between the sensor path and an inlet, and a downstream curved path between the sensor path and an outlet. The housing includes a measurement narrowed portion that gradually narrows the measurement flow path in a direction from the inlet toward the physical quantity sensor. An upstream end of the sensor support is provided upstream of the measurement narrowed portion in an arrangement cross section along an imaginary straight line passing through the physical quantity sensor and extending in an arrangement direction in which the upstream curved path and the downstream curved path are arranged.

A physical quantity measurement device includes a housing forming a measurement flow path including a measurement inlet and a measurement outlet. The measurement flow path includes a sensor path in which a physical quantity sensor is disposed, an upstream curved path curved to extend from the sensor path toward the measurement inlet, and a downstream curved path curved to extend from the sensor path toward the measurement outlet. An inner surface of the housing includes an upstream outer curved surface that defines an outer outline of a curved part of the upstream curved path, and a downstream outer curved surface that defines an outer outline of a curve part of the downstream curved path. A degree of recess of the downstream outer curved surface is larger than a degree of recess of the upstream outer curved surface.