Abstract: In an embodiment, a method of sensing a flow comprises performing a measurement cycle for a first period of time, powering off the at least one upstream resistive element and the at least one downstream resistive element for a second period of time, and performing another measurement cycle for a third period of time. Performing the measurement cycle comprises supplying a current to the upstream resistive element and the downstream resistive element arranged in a bridge, resistively heating the upstream resistive element and the downstream resistive element to a temperature above an ambient temperature, and detecting an imbalance in the bridge resulting from a temperature difference between the at least one upstream resistive element and the at least one downstream resistive element in response to the flow of a fluid past the flow sensor.

Abstract: In an embodiment, a method of sensing a flow comprises performing a measurement cycle for a first period of time, powering off the at least one upstream resistive element and the at least one downstream resistive element for a second period of time, and performing another measurement cycle for a third period of time. Performing the measurement cycle comprises supplying a current to the upstream resistive element and the downstream resistive element arranged in a bridge, resistively heating the upstream resistive element and the downstream resistive element to a temperature above an ambient temperature, and detecting an imbalance in the bridge resulting from a temperature difference between the at least one upstream resistive element and the at least one downstream resistive element in response to the flow of a fluid past the flow sensor.

Abstract: Apparatus and associated methods relate to a temperature-compensated drive for a heating element used in a micro-bridge flow sensor. In some embodiments, the heating element may be located substantially between two temperature sensors. The two temperature sensors may be convectively coupled to the heater by a fluid ambient. When the fluid ambient is flowing, one of the temperature sensors may be upstream of the heating element, and one of the temperature sensors may be downstream. The fluid may be heated by the heating unit, and this heated fluid may then flow past the downstream temperature sensor. The two temperature sensors may be used in a Wheatstone bridge configuration. In some embodiments, an output signal of the Wheatstone bridge may be indicative of a measure of fluid flow. The temperature-compensated drive for the heating element may enhance, for example, the flow meter's disturbance rejection of ambient temperature.

Abstract: Flow sensor assemblies having increased flow range capabilities are disclosed. In one illustrative embodiment, a flow sensor assembly includes a housing with an inlet flow port, an outlet flow port, a fluid channel extending between the inlet flow port and the outlet flow port, and a bypass channel having a pair of taps fluidly connected to the fluid channel at separate locations. A flow sensor for sensing a measure related to a flow rate of a fluid flowing through the fluid channel can positioned in the bypass channel. A pressure differential between the two taps of the bypass channel can drive a fraction of a fluid flowing through the fluid channel through the bypass channel. The flow sensor assembly may be configured to achieve, control, and/or balance a desired fraction of fluid flow through the bypass channel and past the flow sensor.

Abstract: Apparatus and associated methods relate to a temperature-compensated drive for a heating element used in a micro-bridge flow sensor. In some embodiments, the heating element may be located substantially between two temperature sensors. The two temperature sensors may be convectively coupled to the heater by a fluid ambient. When the fluid ambient is flowing, one of the temperature sensors may be upstream of the heating element, and one of the temperature sensors may be downstream. The fluid may be heated by the heating unit, and this heated fluid may then flow past the downstream temperature sensor. The two temperature sensors may be used in a Wheatstone bridge configuration. In some embodiments, an output signal of the Wheatstone bridge may be indicative of a measure of fluid flow. The temperature-compensated drive for the heating element may enhance, for example, the flow meter's disturbance rejection of ambient temperature.

Abstract: This disclosure relates generally to flow sensors, and more particularly, to flow sensors that include a pressure related output signal. In one example, a flow sensor assembly may include a housing with an inlet flow port, an outlet flow port and a fluid channel extending therebetween, with a flow sensing element positioned in the housing and exposed to the fluid channel. A filter insert may be situated in the fluid channel, sometimes upstream of the flow sensor. When so configured, the flow sensor assembly may output a pressure or differential pressure based, at least in part, on a value of the flow rate through the fluid channel as sensed by the flow sensor.

Abstract: Flow sensor assemblies having increased flow range capabilities are disclosed. In one illustrative embodiment, a flow sensor assembly includes a housing with an inlet flow port, an outlet flow port, a fluid channel extending between the inlet flow port and the outlet flow port, and a bypass channel having a pair of taps fluidly connected to the fluid channel at separate locations. A flow sensor for sensing a measure related to a flow rate of a fluid flowing through the fluid channel can positioned in the bypass channel. A pressure differential between the two taps of the bypass channel can drive a fraction of a fluid flowing through the fluid channel through the bypass channel. The flow sensor assembly may be configured to achieve, control, and/or balance a desired fraction of fluid flow through the bypass channel and past the flow sensor.

Abstract: Flow sensor assemblies having increased flow range capabilities are disclosed. In one illustrative embodiment, a flow sensor assembly includes a housing with an inlet flow port, an outlet flow port, a fluid channel extending between the inlet flow port and the outlet flow port, and a bypass channel having a pair of taps fluidly connected to the fluid channel at separate locations. A flow sensor for sensing a measure related to a flow rate of a fluid flowing through the fluid channel can positioned in the bypass channel. A pressure differential between the two taps of the bypass channel can drive a fraction of a fluid flowing through the fluid channel through the bypass channel. The flow sensor assembly may be configured to achieve, control, and/or balance a desired fraction of fluid flow through the bypass channel and past the flow sensor.

Abstract: This disclosure relates generally to flow sensors, and more particularly, to flow sensors that include a pressure related output signal. In one example, a flow sensor assembly may include a housing with an inlet flow port, an outlet flow port and a fluid channel extending therebetween, with a flow sensing element positioned in the housing and exposed to the fluid channel. A filter insert may be situated in the fluid channel, sometimes upstream of the flow sensor. When so configured, the flow sensor assembly may output a pressure or differential pressure based, at least in part, on a value of the flow rate through the fluid channel as sensed by the flow sensor.

Abstract: A flow sensor apparatus and method. A seal with a conductive interconnect is provided that includes a mass flow sense element mounted to a housing containing a thick film and/or thin film bridge structure for sensing media (e.g., mass flow) within a flow tube. The seal effectively isolates wirebond pads and electrical connections from the sensed media. The media, whether liquid or gas, can contain ionics that eventually contaminate the top of the mass flow sense element. The use of the seal with the conductive interconnect thus seals off the electrical connections and prevents exposure to the sensed media.

Abstract: A flow sensor apparatus and method. A seal with a conductive interconnect is provided that includes a mass flow sense element mounted to a housing containing a thick film and/or thin film bridge structure for sensing media (e.g., mass flow) within a flow tube. The seal effectively isolates wirebond pads and electrical connections from the sensed media. The media, whether liquid or gas, can contain ionics that eventually contaminate the top of the mass flow sense element. The use of the seal with the conductive interconnect thus seals off the electrical connections and prevents exposure to the sensed media.