The present invention provides methods for determining a parameter associated with a flow of a fluid located within a fluid conduit, based on measuring the difference between electrical signals of at least two second sensing elements contacting different positions on am exterior of the fluid conduit. The sensing elements comprise an assembly of nanoparticles being in electric contact with conductive electrodes; wherein the electrical signals of the sensing elements are responsive to at least one of pressure and temperature. Further provided is a clamping device configured to reduce a cross-sectional diameter of a portion of the fluid conduit, in order to determine said parameter.

A method for determining a flow rate and/or a flow velocity of a medium interacting with at least a first and a second temperature sensor element and a heating element, wherein the method comprises the following method steps: heating the medium by means of the heating element for a predetermined heating duration, wherein the medium before the heating is largely in thermal equilibrium with at least the first and second temperature sensor elements; registering at least a first and a second measured value with the assistance of the first temperature sensor element and at least a third and a fourth measured value with the assistance of the second temperature sensor element for characterizing first and second temperature rises of the medium; and ascertaining the flow rate and/or flow velocity of the medium based on the at least two temperature rises.

A thermal flowmeter comprises a heating element thermally coupled to a flowing medium, a first temperature sensor and second temperature sensor. The first temperature sensor detects a flowing medium temperature in a region not affected by the heating element. The second temperature sensor detects a temperature of the heating element and also serves as a heating element. A control unit controls heating power of the heating element based on the difference between the detected temperatures at a predetermined time. The control unit provides a square wave signal to the second temperature sensor so that in a high phase it acts as heating element and in a low phase as a temperature sensor.

Methods and apparatus for non-intrusively measuring fluid flow in a conduit, such as a pipe or tubing. The apparatus includes an insulator having self-adhesive inner surface attachable to the conduit, a temperature sensor on the inner surface of the insulator that senses the conduit surface temperature, a heat source on the inner surface of the insulator that imparts heat into the conduit, and a microcontroller connected to the heat source activator and the sensor assembly. In one embodiment, a baseline conduit temperature is measured, and the heat source raises the temperature of the conduit by a predetermined amount. When the conduit reaches target temperature, the heat source is deactivated and the cooling time for the conduit to return to its baseline temperature is measured. Fluid flow rate is determined from the cooling time, the temperature rise within a predetermined time, a temperature drop within a predetermined time, and/or a temperature gradient over time.

A thermal type flow meter includes a first resistor (R1) which is disposed along a flow path through which a fluid flows, generates heat when a current is applied, and outputs a first output signal indicating a heat generation temperature, a second resistor (R2) which is disposed at a position different from that of the first resistor along the flow path and outputs a second output signal indicating a temperature of the fluid, and a current application unit configured to apply a current to the first resistor so that the first output signal indicates a predetermined temperature. A parameter for converting the difference between the first output signal and the second output signal when a predetermined input is received if the current is applied into a target value is determined. The flow rate is acquired using the parameter, the difference detected after the parameter is determined, and a predetermined function.

A device for detecting air flows includes an air line channeling an air flow. The line (for example a tube) includes at least one first temperature sensor and one second temperature sensor (inside the tube). At least one of the sensors is subjected to periodic temperature fluctuations controlled by at least one heating device, such as a variable-current power source dedicated to the sensor.

Various methods, apparatuses, and systems for sensing a flow of fluid are provided. The apparatus includes, but not limited to: a membrane structure defining a heated area; a heating structure disposed over the membrane structure and configured to heat the heated area, where the heating structure has a centerline; a first thermopile including a plurality of first thermocouples disposed upstream of the centerline, where at least a portion of the plurality of first thermocouples are disposed over the membrane structure and at least one junction of the plurality of first thermocouples has rounded corners; and a second thermopile including a plurality of second thermocouples disposed downstream of the centerline, where at least a portion of the plurality of second thermocouples are disposed over the membrane structure and at least one junction of the plurality of second thermocouples has rounded corners.

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.

An apparatus includes a microfluidic channel and a flow sensor along the microfluidic channel. The flow sensor includes a heat emitting resistor for connection to an electric current source, analytical parameter sensor and electronics. The heat emitting resistor has a resistance that varies in response to temperature. The electrical parameter sensor is to sense an electrical parameter of the heat emitting resistor that is based on the resistance of the heat emitting resistor. The electronics determine a flow based on the sensed electrical parameter.

The invention is an apparatus and method for measuring the flow rate of a liquid through a conduit. The apparatus is based on a flow rate meter which is adapted to accurately measure the volumetric flow rate of a liquid using a simple, cost and energy effective, and accurate method using only one temperature sensor. The method is based on applying a pulse of thermal energy to the flowing liquid and measuring the temperature increase as a function of time and energy input. By comparing these measurements to a calibration table made by performing similar measurements for known flow rates, the rate of flow can be determined. One application, which will be described to illustrate the features of the method and apparatus of the invention, is measurement of the flow rate of urine excreted by a catheterized patient.