Example systems, apparatuses, and methods are disclosed sensing a flow of fluid using a thermopile-based flow sensing device. An example apparatus includes a flow sensing device comprising a heating structure having a centerline. The flow sensing device may further comprise a thermopile. At least a portion of the thermopile may be disposed over the heating structure. The thermopile may comprise a first thermocouple having a first thermocouple junction disposed upstream of the centerline of the heating structure. The thermopile may further comprise a second thermocouple having a second thermocouple junction disposed downstream of the centerline of the heating structure.

There is disclosed herein a flow sensor comprising: a first substrate comprising an etched portion; a dielectric layer located on the first substrate, where the dielectric layer comprises at least one dielectric membrane located over the etched portion of the first substrate; a first heating element and a second heating element located on or within the dielectric membrane; and a controller coupled with the first heating element and the second heating element. The first heating element and the second heating element are arranged to intersect one another within or over an area of the dielectric membrane. The controller is configured to: take a measurement from the second heating element; determine a calibration parameter using the measurement from the second heating element; take a measurement from the first heating element; and determine a flow rate through the flow sensor using the determined calibration parameter and the measurement from the first heating element.

Example systems, apparatuses, and methods are disclosed sensing a flow of fluid using a thermopile-based flow sensing device. An example apparatus includes a flow sensing device comprising a heating structure having a centerline. The flow sensing device may further comprise a thermopile. At least a portion of the thermopile may be disposed over the heating structure. The thermopile may comprise a first thermocouple having a first thermocouple junction disposed upstream of the centerline of the heating structure. The thermopile may further comprise a second thermocouple having a second thermocouple junction disposed downstream of the centerline of the heating structure.

A non-invasive thermal dispersion flow meter with chronometric monitor for fluid leak detection includes a heater, an ambient temperature sensor and a flow rate sensor which are configured to sense the temperature of a fluid in a conduit, and then monitor the flow of that fluid through the conduit. Based upon the ambient temperature sensor readings, the flow rate sensor and heater may be adjusted to optimize the operation of the system to detect leaks. Based on the sensor readings, the flow may be adjusted to prevent damage and leaks by relieving the system of excess pressure. Geographic location, occupancy sensors and occupant identifiers are used to control the system to facilitate operation and minimize leak damage when occupants are away.

The packaged flow sensor is a packaged flow sensor for use by being fixed to an external substrate and includes a flow sensor chip including a sensor unit configured to detect a flow rate of a fluid, a case member including an opening toward the external substrate and configured to house the sensor unit in a state in which the sensor unit faces the opening, and a fixing member protruding from the case member toward the external substrate and configured to fix the packaged flow sensor to the external substrate.

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 flow sensor including a fluid flow path, a first sensor configured to determine a first measurement of a thermal diffusivity and/or a viscosity of a fluid in the fluid flow path, a second sensor configured to determine a second measurement of a fluid flow velocity and/or a volumetric flow rate of the fluid in the fluid flow path, and at least one processor configured to adjust the second measurement based on the first measurement. A method including receiving fluid in a fluid flow path of a flow sensor, determining a first measurement of a thermal diffusivity and/or a viscosity of the fluid in the fluid flow path, determining a second measurement of a fluid flow velocity and/or a volumetric flow rate of the fluid in the fluid flow path, and adjusting the second measurement based on the first measurement.

We disclose herein a flow and thermal conductivity sensor comprising a semiconductor substrate comprising an etched portion, a dielectric region located on the semiconductor substrate, wherein the dielectric region comprises at least one dielectric membrane located over the etched portion of the semiconductor substrate and a heating element located within the dielectric membrane. The dielectric membrane comprises one or more discontinuities located between the heating element and an edge of the dielectric membrane.

A flow sensor chip capable of preventing power from being wasted during the electrification of a heater is provided. The flow sensor chip includes a first lead portion connected to an end of a heater portion, a second lead portion connected to the other end of the heater portion, a first electrode pad connected, directly or through a connection portion formed of a material having an electrical conductivity equal to or greater than the heater conductivity, to an end of the first lead portion on a side which is not connected to the heater portion, and a second electrode pad connected, directly or through a connection portion formed of a material having an electrical conductivity equal to or greater than the heater conductivity, to an end of the second lead portion on a side which is not connected to the heater portion.

A flow sensor including a fluid flow path, a first sensor configured to determine a first measurement of a thermal diffusivity and/or a viscosity of a fluid in the fluid flow path, a second sensor configured to determine a second measurement of a fluid flow velocity and/or a volumetric flow rate of the fluid in the fluid flow path, and at least one processor configured to adjust the second measurement based on the first measurement. A method including receiving fluid in a fluid flow path of a flow sensor, determining a first measurement of a thermal diffusivity and/or a viscosity of the fluid in the fluid flow path, determining a second measurement of a fluid flow velocity and/or a volumetric flow rate of the fluid in the fluid flow path, and adjusting the second measurement based on the first measurement.