An object is to provide a flow sensor element is non-directional and has an excellent sensor sensitivity. A flow sensor element includes a base body having a spherical shape, and a temperature-sensitive film pattern that is disposed over the entirety of a surface of the base body, and changes in an electrical resistance value due to a change in temperature. It is preferable that the temperature-sensitive film pattern be formed by trimming a temperature-sensitive film that has been formed on the surface of the base body. In the flow sensor element, the temperature-sensitive film pattern can be disposed over the entirety of the surface of the base body having a spherical shape. This enables a constant sensor sensitivity to be obtained regardless of a direction of a fluid, and the accuracy of detection of a flow rate can be improved.

An object is to provide a flow sensor element is non-directional and has an excellent sensor sensitivity. A flow sensor element includes a base body having a spherical shape, and a temperature-sensitive film pattern that is disposed over the entirety of a surface of the base body, and changes in an electrical resistance value due to a change in temperature. It is preferable that the temperature-sensitive film pattern be formed by trimming a temperature-sensitive film that has been formed on the surface of the base body. In the flow sensor element, the temperature-sensitive film pattern can be disposed over the entirety of the surface of the base body having a spherical shape. This enables a constant sensor sensitivity to be obtained regardless of a direction of a fluid, and the accuracy of detection of a flow rate can be improved.

The sensor of a fluid sensor system includes an outer peripheral sensor unit including three or more sensor pairs to surround and sandwich the heating element. The computing device of the system includes a first identification unit identifies a sensor pair in which an output difference between an output value corresponding to a temperature detected by one temperature sensor of the sensor pair and an output value corresponding to a temperature detected by the other temperature sensor of the sensor pair is largest, a second identification unit identifies other sensor pairs adjacent to the identified sensor pair in the circumferential direction, and a flow direction estimation unit estimates the flow direction of the fluid on the basis of the output difference in the sensor pair having the largest output difference and output differences in the other sensor pairs adjacent to the sensor pair in the circumferential direction.

A Wheatstone bridge flowmeter is formed on a base substrate with a fluid passageway formed over or through a top surface of the base substrate. Resistors forming the Wheatstone bridge and a heater are arranged in a linear physical arrangement along the passageway, such that two resistors on one side of the Wheatstone bridge are sequentially upstream of the heater and two resistors on the other side of the Wheatstone bridge are sequentially downstream of the heater, establishing a sequential arrangement along the fluid passageway of two of the resistors, the heater and the other two resistors. Heating of the fluid by the heater creates a differential in the temperatures of the resistors, thereby changing the output sensing voltages across the Wheatstone bridge.

A Wheatstone bridge flowmeter is formed on a base substrate with a fluid passageway formed over or through a top surface of the base substrate. Resistors forming the Wheatstone bridge and a heater are arranged in a linear physical arrangement along the passageway, such that two resistors on one side of the Wheatstone bridge are sequentially upstream of the heater and two resistors on the other side of the Wheatstone bridge are sequentially downstream of the heater, establishing a sequential arrangement along the fluid passageway of two of the resistors, the heater and the other two resistors. Heating of the fluid by the heater creates a differential in the temperatures of the resistors, thereby changing the output sensing voltages across the Wheatstone bridge.

A physical quantity measurement device includes a housing forming a measurement flow path through which the fluid flows and a container space that houses a part of a detection unit. An inner surface of the housing includes a housing intersecting surface that intersects an arrangement direction in which the measurement flow path and the container space are arranged, a housing flow path surface extending from the housing intersecting surface toward the measurement flow path, and a housing container surface extending from the housing intersecting surface toward the container space. The housing includes a housing partition that protrudes from the inner surface toward the detection unit and contacts the detection unit between the housing and the detection unit such that the housing partition separates the measurement flow path and the container space from each other.

An improved flow sensor (104) is provided to enable accurate dose measurements to be made with little or no sensor calibration due to highly accurate flow channel cross section. The flow channel is formed as a metal tube (1301). A sensor window (1304) is formed in the side wall of the metal tube (1301), and the flow sensor (1200) is mounted in the sensor window. A flow manifold is formed around the metal flow channel.

An improved flow sensor (104) is provided to enable accurate dose measurements to be made with little or no sensor calibration due to highly accurate flow channel cross section. The flow channel is formed as a metal tube (1301). A sensor window (1304) is formed in the side wall of the metal tube (1301), and the flow sensor (1200) is mounted in the sensor window. A flow manifold is formed around the metal flow channel.

Provided is a thermal flow rate meter capable of individually correcting different pulsation errors generated in an upstream side temperature sensor and a downstream side temperature sensor. A thermal flow rate meter 1 which measures a flow rate of a gas based on a temperature difference between an upstream side temperature sensor 12 and a downstream side temperature sensor 13, which are arranged on the upstream side and the downstream side of a heating element 11. The thermal flow rate meter includes: a detection element 10 that individually outputs an output signal of the upstream side temperature sensor 12 and an output signal of the downstream side temperature sensor 13; and compensator 20 that individually performs response compensation of the output signal of the upstream side temperature sensor 12 and the output signal of the downstream side temperature sensor 13.

Provided is a thermal flow rate meter capable of individually correcting different pulsation errors generated in an upstream side temperature sensor and a downstream side temperature sensor. A thermal flow rate meter 1 which measures a flow rate of a gas based on a temperature difference between an upstream side temperature sensor 12 and a downstream side temperature sensor 13, which are arranged on the upstream side and the downstream side of a heating element 11. The thermal flow rate meter includes: a detection element 10 that individually outputs an output signal of the upstream side temperature sensor 12 and an output signal of the downstream side temperature sensor 13; and compensator 20 that individually performs response compensation of the output signal of the upstream side temperature sensor 12 and the output signal of the downstream side temperature sensor 13.