Methods and apparatuses associated with flow sensing devices are provided. An example flow sensing device includes a flow cap component and a sensor component. The flow cap component or sensor component may include a heating element. The flow cap component can at least partially define a flow channel configured for a media to flow therethrough. The heater element may be orthogonal or perpendicular to the flow channel. The sensor component may include at least one thermal sensing element disposed upstream of the heater element and at least one thermal sensing element disposed downstream of the heater element. The sensor component may include two or more thermal sensing elements disposed in either the upstream direction or downstream direction of the heater element. Thermal sensing elements may be spaced different distances from the heater element to increase the accuracy and precision of flow rate measurement at low flow rates.

Methods and apparatuses associated with an example flow sensing device are provided. In some examples, the flow sensing device may include a flow cap component and a sensor component. In some examples, the flow cap component may include a heating element disposed in a first layer of the flow cap component. In some examples, the sensor component may include at least one thermal sensing element disposed in a second layer of the sensor component. In some examples, the first layer and the second layer are noncoplanar. In some examples, the flow cap component may be bonded to a first surface of the sensor component to form a flow channel. In some examples, the first layer and the second layer may be noncoplanar and separated by the flow channel.

Methods and apparatuses associated with an example flow sensing device are provided. In some examples, the flow sensing device may include a flow cap component and a sensor component. In some examples, the flow cap component may include a heating element disposed in a first layer of the flow cap component. In some examples, the sensor component may include at least one thermal sensing element disposed in a second layer of the sensor component. In some examples, the first layer and the second layer are noncoplanar. In some examples, the flow cap component may be bonded to a first surface of the sensor component to form a flow channel. In some examples, the first layer and the second layer may be noncoplanar and separated by the flow channel.

A flow velocity sensor includes a substrate, a resistor, and a signal processing section. The substrate has first and second substrate surfaces outwardly opposite to each other. The first substrate surface is exposed to a fluid. The resistor is mounted on the second substrate surface. The resistor has a heat generating portion facing the second substrate surface. The signal processing section is configured to receive a signal from the resister. The signal from the resistor represents heat dissipation of the resistor. A fluid velocity is detected based on the signal from the resistor.

A thin film is formed on a substrate on which an opening having two opposite sides are formed, and forms a membrane. The thin film has an upstream temperature sensor and a downstream temperature sensor on both sides of a heater. A heat conductive member covers the two sides and is arranged on both sides of the heater, the upstream temperature sensor, and the downstream temperature sensor so as to promote heat conduction from the heater to the substrate. When an end of the opening on the membrane side is defined as an upper end and an end on the side away from the membrane is defined as a lower end, the heat conductive member covers from the upper end to the lower end of the opening in a normal direction of the membrane.

A thin film is formed on a substrate on which an opening having two opposite sides are formed, and forms a membrane. The thin film has an upstream temperature sensor and a downstream temperature sensor on both sides of a heater. A heat conductive member covers the two sides and is arranged on both sides of the heater, the upstream temperature sensor, and the downstream temperature sensor so as to promote heat conduction from the heater to the substrate. When an end of the opening on the membrane side is defined as an upper end and an end on the side away from the membrane is defined as a lower end, the heat conductive member covers from the upper end to the lower end of the opening in a normal direction of the membrane.

Methods and apparatuses associated with an example flow sensing device are provided. In some examples, the flow sensing device may include a flow cap component and a sensor component. In some examples, the flow cap component may include a heating element disposed in a first layer of the flow cap component. In some examples, the sensor component may include at least one thermal sensing element disposed in a second layer of the sensor component. In some examples, the first layer and the second layer are noncoplanar. In some examples, the flow cap component may be bonded to a first surface of the sensor component to form a flow channel. In some examples, the first layer and the second layer may be noncoplanar and separated by the flow channel.

Methods and apparatuses associated with an example flow sensing device are provided. In some examples, the flow sensing device may include a flow cap component and a sensor component. In some examples, the flow cap component may include a heating element disposed in a first layer of the flow cap component. In some examples, the sensor component may include at least one thermal sensing element disposed in a second layer of the sensor component. In some examples, the first layer and the second layer are noncoplanar. In some examples, the flow cap component may be bonded to a first surface of the sensor component to form a flow channel. In some examples, the first layer and the second layer may be noncoplanar and separated by the flow channel.

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 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.