Granted Patent B2

US 12,656,191 · App. 18/055,548 · Granted Jun 16, 2026

Inventors: Claudio Falco (Cambridge, GB); Syed Zeeshan Ali (Cambridge, GB)

Assignee: FLUSSO LIMITED

G01K13/026G01K7/02G01K7/16G01P5/10G01P13/02

Abstract

Claims (54)

1 . A sensor for sensing direction of fluid-flow, the sensor comprising:

a first resistor acting as a heating element;

a second resistor acting as a first active

temperature sensing element, the first resistor

and the second resistor being identical;

and a processor;

wherein the processor is configured to:

receive a first signal corresponding to a first sensed temperature from the first active temperature sensing element; and

determine a direction of fluid-flow based on the first signal corresponding to the first sensed temperature and a threshold value;

receive a third signal from the heating element;

determine a magnitude of fluid-flow based on a comparison between the third signal from the heating element and a calibration value, and

periodically swap the first resistor and the second resistor so that the first resistor acts as the first active temperature sensing element and the second resistor acts as the heating element.

2 . The sensor according to claim 1 , wherein the processor is configured to determine the direction of fluid-flow based on a difference between the first sensed temperature and the threshold value.

3 . The sensor according to claim 1 , further comprising an ambient temperature sensing element, the ambient temperature sensing element being configured to detect an ambient temperature;

wherein the processor is further configured to determine the threshold value based on the ambient temperature.

4 . The sensor according to claim 3 , wherein the ambient temperature sensing element is thermally decoupled from the heating element.

5 . The sensor according to claim 3 , wherein the processor is configured to determine the threshold value based further on a signal from the heating element.

6 . The sensor according to claim 1 , further comprising: a semiconductor substrate comprising an etched portion; and

a dielectric region located on the semiconductor substrate, wherein the dielectric region comprises a dielectric membrane located over the etched portion of the semiconductor substrate;

wherein the heating element is located within the dielectric membrane.

7 . The sensor according to claim 6 , wherein the first active temperature sensing element is located on or within the dielectric membrane, and wherein the first active temperature sensing element is spatially separated from the heating element.

8 . The sensor according to claim 6 , wherein an ambient temperature sensing element is located outside of the dielectric membrane.

9 . The sensor according to claim 6 , wherein an ambient temperature sensing element is located within the dielectric membrane, and wherein the ambient temperature sensing element is thermally isolated from the heating element.

10 . The sensor according to claim 9 , wherein the ambient temperature sensing element is thermally isolated from the heating element by one or more recessed regions of the dielectric membrane.

11 . The sensor according to claim 1 , further comprising a second active temperature sensing element, wherein the processor is further configured to:

receive a second signal corresponding to a second sensed temperature from the second active temperature sensing element; and

determine the direction of fluid-flow based additionally on the second signal corresponding to the second sensed temperature.

12 . The sensor according to claim 11 , wherein the processor is further configured to determine the direction of fluid-flow based on a difference between the second signal and a second threshold value.

13 . The sensor according to claim 12 , wherein the first active temperature sensing element and the second active temperature sensing element are located at different distances from the heating element.

14 . The sensor according to claim 11 , wherein the first active temperature sensing element and the second active temperature sensing element are located at substantially the same distance from the heating element, and wherein the processor is further configured to:

determine a difference between the first and second sensed temperatures; and

determine the direction of fluid-flow based on a difference between:

the difference between the first and second sensed temperatures; and

the threshold value.

15 . A method for sensing direction of fluid-flow, the method comprising:

operating a heating element in a fluid-flow path;

receiving a first signal corresponding to a first sensed temperature from an active temperature sensing element;

determining a direction of fluid-flow based on the first sensed temperature and a threshold value;

receiving a third signal from the heating element;

determining a magnitude of fluid-flow based on a comparison between the third signal from the heating element and a calibration value, and

periodically swapping the roles of the heating element and of the active temperature sensing element.

16 . The method according to claim 15 , further comprising:

determining an ambient temperature; and

determining the threshold value based on the ambient temperature.

17 . The method according to claim 16 , comprising determining the threshold value based further on a signal from the heating element.

18 . The method according to claim 15 , further comprising:

determining a second sensed temperature; and

determining the direction of fluid-flow based additionally on the second sensed temperature.

19 . A method of manufacturing a sensor for sensing direction of fluid-flow, the method comprising:

providing a first resistor configured to act as heating element;

providing a second resistor configured to act as first active temperature sensing element, the first resistor and the second resistor being identical;

configuring the first active temperature sensing element to sense a first sensed temperature;

providing a processor; and

configuring the processor to receive a first signal corresponding to the first sensed temperature from the first active temperature sensing element to determine a direction of fluid-flow based on the first sensed temperature and a threshold value; to receive a third signal from the heating element; to determine a magnitude of fluid-flow based on a comparison between the third signal from the heating element and a calibration value, and periodically swap the first resistor and the second resistor so that the first resistor is configured to act as the first active temperature sensing element and the second resistor is configured to act as the heating element.

Assignments (1)

Continuity (1)

References Cited (12)