Patent Description:
<CIT> describes a thermal type flowmeter that includes a sensor element including a heating resistor formed in a thin film part. Upstream and downstream of the heating resistor, temperature sensors are formed. The flow rate is measured using a temperature difference between the temperatures on the upstream side and the downstream side of the heating resistor by use of these temperature sensors.

<CIT> describes an apparatus for determining fluid flow comprising flow obstruction means and two heat-emitting members which are mounted in a geometrically symmetrical arrangement in a conduit. The heat-emitting members are subject to the same heat losses when there is no fluid flow through the conduit and the flow obstruction means cause the two heat-emitting members to be differentially affected by the fluid flow through the conduit. Means responsive to the ratio of the heat losses from the two heat-emitting members are provided for determining the fluid flow.

According to the invention an apparatus for use in determining one or more fluid properties of a fluid flowing in a conduit comprising the features of claim <NUM> and a method for making an apparatus to determine a flow direction in a fluid comprising the features of claim <NUM> are provided.

Consistent with the disclosed embodiments, an apparatus for use in determining one or more fluid properties of a fluid flowing in a conduit is disclosed. The apparatus comprises a substrate including a barrier having a first barrier surface and a second barrier surface. The apparatus further comprises a first flow sensor to generate a first velocity sensor signal, the first flow sensor located at a first sensor distance from the first barrier surface. And the apparatus further comprises a second flow sensor to generate a second velocity sensor signal, the second flow sensor located at a second sensor distance from the second barrier surface, wherein the first sensor distance and the second sensor distance are selected to disturb the fluid flowing in the conduit in such a way as to enable determination of the one or more fluid flow properties from the first velocity sensor signal and the second velocity sensor signal. According to the invention, the apparatus further comprises a third sensor including a pair of third sensor conductive pins, the pair of third sensor conductive pins embedded in the barrier and the substrate.

Consistent with the present disclosure, a method for determining one or more fluid flow properties of a fluid flowing in a conduit is disclosed. The method comprises providing a barrier, the barrier having a first barrier surface and a second barrier surface, in the fluid to cause a difference between upstream characteristics and downstream characteristics of the fluid flowing in the conduit. The method comprises locating a first flow sensor a first distance from the first barrier surface, the first flow sensor to generate a first sensor signal. The method comprises locating a second flow sensor a second distance from the second barrier surface, the second flow sensor to generate a second sensor signal. And the method comprises processing the first sensor signal and the second sensor signal to determine the one or more fluid flow properties of the fluid flowing in the conduit. In some embodiments, the method further comprises responding to the step function change in the fluid flow direction by generating a third sensor signal from a third sensor located in the fluid, the third sensor signal having a third sensor signal rise time of between about three milliseconds and about five milliseconds and the third sensor signal to provide a fluid flow magnitude signal. In some embodiments, the method further comprises recording a sequential plurality of fluid flow sensor readings and a next fluid flow sensor reading following the sequential plurality of fluid flow sensor readings from the first flow sensor signal. The method further comprises generating a curve from a least squares fit to the sequential plurality of fluid flow sensor readings, generating a predicted next data point from the curve, comparing the next fluid flow sensor reading to the predicted next data point and generating a difference between the next fluid flow sensor reading and the predicted next data point, and invalidating the next fluid flow sensor reading, if the difference is substantially greater than zero.

Consistent with the present disclosure, an apparatus for determining one or more fluid flow properties including velocity, magnitude and direction in a conduit. The apparatus comprises a barrier having a first barrier surface and a second barrier surface. The apparatus further comprises a first sensor located at a first sensor distance from the first barrier surface. And the apparatus further comprises a second sensor located at a second sensor distance from the second barrier surface, the second sensor distance substantially equal to the first sensor distance. The apparatus further comprises an electronic system electrically coupled to the first sensor and the second sensor, the electronic system to provide a signal indicative of at least one of one or more fluid flow properties.

Consistent with the present disclosure, an apparatus for use in determining one or more fluid flow properties of a fluid in a conduit is disclosed. The apparatus comprises a substrate including a barrier having a first barrier surface and a second barrier surface. The apparatus further comprises a first sensor coupled to the substrate, the first sensor located at a first sensor distance from the first barrier surface. The apparatus further comprises a second sensor coupled to the substrate, the second sensor located at a second sensor distance from the second barrier surface, the second sensor distance substantially equal to the first sensor distance and the first barrier surface substantially parallel to the second barrier surface. The apparatus further comprises a third sensor including a pair of third sensor conductive pins, the pair of third sensor conductive pins embedded in the barrier and the substrate. The term "conductive pins" includes leads and other electrically conductive structures. The apparatus further comprises a Wheatstone bridge coupled to the first sensor to generate a first sensor fluid flow signal. The signal can be further processed by analog and digital circuits.

Consistent with some other embodiments, a method for making an apparatus to determine a flow direction in a fluid is disclosed The method comprises forming a substrate including a barrier having a first barrier surface, a second barrier surface, and a barrier edge surface including a curved surface, the first barrier surface substantially parallel to the second barrier surface. The method comprises locating a first sensor and a second sensor substantially symmetrically with respect to the first barrier surface and the second barrier surface, the first sensor including a pair of first sensor conductive pins and the second sensor including a pair of second sensor conductive pins. The method further comprises embedding the pair of first sensor conductive pins and the pair of second sensor conductive pins in the substrate. The method further comprises aligning a third sensor substantially parallel to the first sensor and the second sensor, the third sensor including a pair of third sensor conductive pins. The method further comprises embedding the pair of third sensor conductive pins in the substrate and the barrier.

Consistent with the present disclosure , a method for determining one or more fluid flow properties of a fluid in a conduit is disclosed. The method comprises responding to a change in a fluid flow direction by generating a first sensor signal having a first sensor signal from a first sensor located in the fluid. The method further comprises responding to the change in the fluid flow direction by generating a second sensor signal having a second senor signal from a second sensor located in the fluid. The method further comprises comparing the first sensor signal to the second sensor signal to determine the flow direction. The method further comprises responding to the change in the fluid flow direction by generating a third sensor signal from a third sensor located in the fluid, the third sensor signal having a third sensor signal rise time of between about three milliseconds and about five milliseconds and the third sensor signal to provide a fluid flow magnitude signal.

Consistent with the present disclosure, a system to monitor a fluid flow direction in a fluid that flows between a patient and a ventilator is disclosed. The system comprises a fluid flow direction sensor including a barrier, the fluid flow direction sensor to detect the fluid flow direction in the fluid. The system further comprises a conduit coupled to the fluid flow direction sensor, the conduit to couple to the patient and the ventilator. The system further comprises a control system to couple to the fluid flow direction sensor to monitor the fluid flow direction.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Reference will now be made in detail to the exemplary embodiments of the present disclosure described below and illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout to refer to same or like parts.

While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, embodiments, and substitution of equivalents, that all fall within the scope of the disclosure. Accordingly, the disclosure is not to be considered as limited by the foregoing or following descriptions.

<FIG> shows an illustration of an apparatus <NUM> for use in determining one or more fluid flow properties of a fluid in a conduit in accordance with some embodiments of the present disclosure. Exemplary fluids include gases and liquids. The apparatus <NUM> includes a substrate <NUM>, a first sensor <NUM> coupled to the substrate <NUM>, and a second sensor <NUM> coupled to the substrate <NUM>. The substrate <NUM> includes a barrier <NUM> having a first barrier surface <NUM> and a second barrier surface <NUM>. The first sensor <NUM> is located at a first sensor distance <NUM> from the first barrier surface <NUM>. The second sensor <NUM> is located at a second sensor distance <NUM> from the second barrier surface <NUM>. In some embodiments, the first sensor distance <NUM> is substantially equal to the second sensor distance <NUM> and the first barrier surface <NUM> is substantially parallel to the second barrier surface <NUM>. In some embodiments, a third sensor <NUM> is coupled to the substrate <NUM>. In some embodiments the first sensor <NUM> and the second sensor <NUM> are fluid flow sensors.

In some embodiments, the apparatus <NUM> for use in determining one or more fluid properties of a fluid flowing in a conduit includes the substrate <NUM> including the barrier <NUM> having the first barrier surface <NUM> and the second barrier surface <NUM>, a first sensor <NUM>, such as a velocity sensor, flow sensor, or other sensor to detect other fluid properties, to generate a first velocity sensor signal, the first sensor located at a first sensor distance <NUM> from the first barrier surface <NUM>, and the second sensor <NUM>, such as a velocity sensor, flow sensor, or other sensor to detect other fluid properties, to generate a second velocity sensor signal, the second sensor <NUM> located at a second sensor distance <NUM> from the second barrier surface <NUM>, wherein the first sensor distance <NUM> and the second sensor distance <NUM> are selected to disturb the fluid flowing in the conduit in such a way as to enable determination of the one or more fluid flow properties from the first velocity sensor signal and the second velocity sensor signal.

<FIG> shows a flow profile for a computational fluid dynamics model for a barrier inserted into a fluid flowing from left to right in a conduit in accordance with some embodiments of the present disclosure. As can be seen by comparing the flow lines at the barrier, the flow velocity to the left of the barrier (upstream) is greater than the flow velocity to the right of the barrier (downstream). The streamlines in the "shadow" of the barrier form a vortex. The upstream streamlines to the left of the barrier when compared to the downstream streamlines to the right of the barrier indicate that the flow velocity is greater to the left of the barrier than the flow velocity to the right of the barrier.

Referring again to <FIG>, in operation, the apparatus <NUM> is coupled to a conduit such that the first sensor <NUM>, the second sensor <NUM>, and the third sensor <NUM> are in contact with a fluid. As the fluid flows in a direction from the first sensor <NUM> to the second sensor <NUM>, the fluid encounters the first sensor <NUM>, the barrier <NUM>, and the second sensor <NUM>. The barrier <NUM> casts a "shadow" on the second sensor <NUM>. Referring to <FIG>, and as shown in <FIG>, the flow rate at the first sensor <NUM> (upstream from the barrier) is greater than the flow rate at the second sensor <NUM> (downstream from the barrier). Thus, at a particular point in time the first sensor <NUM> generates a first sensor signal, the second sensor <NUM> generates a second sensor signal, and because the flow rate is greater at the first sensor <NUM> than at the second sensor <NUM> the first sensor signal is greater than the second sensor signal. Hence, the direction of flow of the fluid can be determined. The third sensor <NUM> generates a signal indicative of the flow rate or flow magnitude at the third sensor <NUM>. In some embodiments, the third sensor <NUM> in combination with either the first sensor <NUM> or the second sensor <NUM> is used to detect the direction of flow of the fluid. The apparatus <NUM> has a dynamic range of from about. <NUM> liters per minute up to about <NUM> liters per minute.

The substrate <NUM> provides a base for mounting the first sensor <NUM>, the second sensor <NUM>, and the third sensor <NUM>. The first sensor <NUM> includes a pair of first sensor conductive pins <NUM>. In some embodiments, the pair of first sensor conductive pins <NUM> includes a distance <NUM> between the pair of first sensor conductive pins <NUM> of between about. <NUM> inches and. <NUM> inches. The second sensor <NUM> includes a pair of second sensor conductive pins <NUM>. The third sensor <NUM> includes a pair of third sensor conductive pins <NUM>. As shown in <FIG>, the pair of first sensor conductive pins <NUM> is coupled to a first sensor element <NUM> and embedded in the substrate <NUM>. The pair of first sensor conductive pins <NUM> extend through the substrate <NUM> and are available for electrical connection. Also, as shown in <FIG>, the pair of second sensor conductive pins <NUM> is coupled to a second sensor element <NUM> and embedded in the substrate <NUM>. The pair of second sensor conductive pins <NUM> extend through the substrate <NUM> and are available for electrical connection. Also, as shown in <FIG>, the pair of third sensor conductive pins <NUM> is coupled to a third sensor element <NUM> and embedded in the substrate <NUM> and the barrier <NUM>. The pair of third sensor conductive pins <NUM> extend through the substrate <NUM> and are available for electrical connection.

The substrate <NUM> also includes the barrier <NUM>. The barrier <NUM> includes the first barrier surface <NUM> and the second barrier surface <NUM>. In some embodiments, the first barrier surface <NUM> is substantially parallel to the second barrier surface <NUM>. In some embodiments, the first sensor <NUM> and the second sensor <NUM> are located substantially symmetrically with respect to the first barrier surface <NUM> and the second barrier surface <NUM>. The first sensor <NUM> and the second sensor <NUM> are located substantially symmetrically with respect to the first barrier surface <NUM> and the second barrier surface <NUM> when the distance between the first sensor <NUM> and the second barrier surface <NUM> and the distance between the second sensor <NUM> and the first barrier surface <NUM> are substantially equal.

In some embodiments, the substrate <NUM> and the barrier <NUM> are formed by molding a non-conductive moldable plastic, such as a polycarbonate, to form a unitary structure including the first sensor <NUM>, the second sensor <NUM>, and the third sensor <NUM>. The pair of first sensor conductive pins <NUM>, the pair of second sensor conductive pins <NUM>, and the pair of third sensor conductive pins <NUM> are also embedded in the substrate <NUM>. The molding process enables fabrication of the apparatus <NUM> with tight tolerances on the positioning of the first sensor <NUM> with respect to the first barrier surface <NUM>, the second sensor <NUM> with respect to the second barrier surface <NUM>, and the third sensor <NUM> with respect to a barrier edge surface <NUM>, which in some embodiments includes a curved surface. The molding process also enables the fabrication of the apparatus <NUM> with the first barrier surface <NUM> substantially parallel to the second barrier surface <NUM>.

The first sensor <NUM> is located at the first sensor distance <NUM> from the first barrier surface <NUM>. In some embodiments, the first sensor distance <NUM> is between about. <NUM> inches and about. <NUM> inches. In some embodiments, the first sensor distance <NUM> is between about. <NUM> inches and about. <NUM> inches. In some embodiments the first sensor distance is between about. <NUM> inches and about. <NUM> inches. In some embodiments, the first sensor distance <NUM> is about. <NUM> inches. In some embodiments, the first sensor <NUM> and the second sensor <NUM> are each located in a vortex created by the barrier <NUM>.

The second sensor <NUM> is located at the second sensor distance <NUM> from the second barrier surface <NUM>. In some embodiments, the second sensor distance <NUM> is between about. <NUM> inches and about. <NUM> inches. In some embodiments, the second sensor distance <NUM> is between about. <NUM> inches and about. <NUM> inches. In some embodiments, the second sensor distance <NUM> is between about. <NUM> inches and about. <NUM> inches. In some embodiments, the second sensor distance <NUM> is about. <NUM> inches.

The first sensor distance <NUM> and the second sensor distance <NUM>, in some embodiments, are selected to maximize the difference between the first sensor signal generated at the first sensor <NUM> and the second sensor signal generated at the second sensor <NUM> in response to a step function change in fluid flow direction.

The third sensor <NUM> is located at a third sensor distance <NUM> from the barrier edge surface <NUM>. In some embodiments, the third sensor distance <NUM> is up to about. <NUM> inches. In some embodiments, the third sensor distance <NUM> is about. <NUM> inches.

The first sensor <NUM>, the second sensor <NUM>, and the third sensor <NUM> are fluid flow sensors. A fluid flow sensor is capable of detecting the magnitude of a fluid flow. The first sensor <NUM>, the second sensor <NUM>, and the third sensor <NUM> are not limited to a particular type of fluid flow sensor. Fast response, high sensitivity, and wide dynamic range are desirable characteristics in a fluid flow sensor. A wide dynamic range enhances the measurable flow resolution and is particularly useful in low flow applications. A small form factor is also desirable, particularly in respiratory applications.

In some embodiments, the first sensor <NUM>, the second sensor <NUM>, and the third sensor <NUM> are thermal dispersion flow sensors. A thermal dispersion flow sensor works by placing a heated sensor inside a flow tube and electronically measuring the amount of heat removed from the sensor by a flowing fluid. At low flow rates the heat removed from the sensor is low. At higher flow rates the heat removed from the sensor is higher.

<FIG> shows an illustration of a thin-film flow sensor <NUM> in accordance with some embodiments of the present disclosure. In some embodiments, the first sensor <NUM>, the second sensor <NUM>, and the third sensor <NUM> (all shown in <FIG>) are thin-film flow sensors. The thin-film flow sensor <NUM> includes a pair of conductive pins <NUM> coupled to a thin-film sensor element <NUM>. The pair of conductive pins <NUM> is electrically coupled to the thin-film sensor element <NUM>. Exemplary materials suitable for use in the fabrication of the pair of conductive pins <NUM> include phosphor bronze and gold. In some embodiments, the pair of conductive pins <NUM> include a phosphor bronze base with gold plating. The pair of conductive pins <NUM> include a pin spacing <NUM>. In some embodiments, the pin spacing <NUM> is between about. <NUM> inches and about. <NUM> inches. In some embodiments, the pin spacing is about. <NUM> inches.

<FIG> shows an illustration of the thin-film sensor element <NUM>, shown in <FIG>, in accordance with some embodiments of the present disclosure. The thin-film sensor element <NUM> includes a non-conductive substrate <NUM>. Exemplary materials suitable for use in connection with the fabrication of the non-conductive substrate <NUM> include glasses, glass-polymers, and polymers. The non-conductive substrate <NUM> is not limited to having a particular shape. Cylinders, cylindrical fibers, and square fibers are exemplary shapes suitable for use in the fabrication of the non-conductive substrate <NUM>. In some embodiments, the non-conductive substrate <NUM> is substantially cylindrical having a diameter <NUM>, a metallic coating <NUM>, and a cylindrical axis <NUM>. The substantially cylindrical non-conductive substrate has straight parallel sides and a circular cross-section. In some embodiments, the diameter <NUM> is about. <NUM> inches. In some embodiments, the metallic coating <NUM> includes a conductive metal such as gold, copper, or platinum. In some embodiments, the metallic coating <NUM> is platinum.

<FIG> shows an illustration of a cross-sectional view <NUM> of the thin-film sensor element <NUM>, shown in <FIG> and Fig. 2B, in accordance with some embodiments of the present disclosure. In some embodiments, the thin film sensor element <NUM> is a platinum coated glass filament. The cross-sectional view <NUM> shows the diameter <NUM> and the metallic coating <NUM>. In some embodiments, the diameter <NUM> is between about. <NUM> and about. <NUM> inches. In some embodiments, the diameter <NUM> is between about. <NUM> and about. <NUM> inches. In some embodiments, the diameter <NUM> is between about. <NUM> and about. <NUM> inches. In some embodiments, the diameter <NUM> is about. <NUM> inches.

<FIG> shows a flow diagram of a method <NUM> for making an apparatus to determine a flow direction in a fluid in accordance with some embodiments of the present disclosure. The method <NUM> includes forming a substrate including a barrier having a first barrier surface, a second barrier surface, and a barrier edge surface including a curved surface, the first barrier surface substantially parallel to the second barrier surface (block <NUM>), locating a first sensor and a second sensor substantially symmetrically with respect to the first barrier surface and the second barrier surface, the first sensor including a pair of first sensor conductive pins and the second sensor including a pair of second sensor conductive pins (block <NUM>), and embedding the pair first sensor conductive pins and the pair of second sensor conductive pins in the substrate (block <NUM>). In some embodiments, the method <NUM> further includes aligning a third sensor substantially parallel to the first sensor and the second sensor, the third sensor including a pair of third sensor conductive pins, and embedding the pair of third sensor conductive pins in the substrate and the barrier. In some embodiments, in the method <NUM>, forming the substrate includes molding the substrate from a non-conductive moldable plastic, such as a polycarbonate, to form a unitary structure.

<FIG> shows a flow diagram of a method <NUM> for determining one or more fluid flow properties of a fluid in a conduit in accordance with some embodiments of the present disclosure. The method <NUM> includes responding to a change in a fluid flow direction by generating a first sensor signal from a first sensor located in the fluid (block <NUM>), responding to the change in the fluid flow direction by generating a second sensor signal from a second sensor located in the fluid (block <NUM>), and comparing the first sensor signal to the second sensor signal to determine the flow direction (block <NUM>).

In some embodiments, responding to a step function change in a fluid flow direction by generating a first sensor signal from a first sensor located in the fluid and generating a second sensor signal from a second sensor located in the fluid includes generating the first sensor signal having a rise time of between about three milliseconds and about five milliseconds and generating the second sensor signal having a rise time of between about three milliseconds and about five milliseconds. In some embodiments, in the method <NUM>, responding to a step function change in a fluid flow direction by generating a first sensor signal from a first sensor located in the fluid and generating a second sensor signal from a second sensor located in the fluid comprises generating the first sensor signal having a rise time of about four milliseconds and generating the second sensor signal having a rise time of about four milliseconds.

In some embodiments, the method <NUM> further includes responding to the step function change in the fluid flow direction by generating a third sensor signal from a third sensor located in the fluid, the third sensor signal having a third sensor signal rise time of between about three milliseconds and about five milliseconds and the third sensor signal to provide a fluid flow magnitude signal.

In some embodiments, generating a first sensor signal having a fast first sensor signal rise time and generating a second sensor signal having a fast second sensor signal rise time includes generating the fast first sensor signal rise time approximately equal to the fast second sensor signal rise time where the step function change in the fluid flow is applied to the first sensor and the second sensor.

<FIG> shows a block diagram of a system <NUM> to monitor a fluid flow direction in a fluid that flows between a patient <NUM> and a ventilator <NUM>. The system <NUM> includes a fluid flow direction sensor <NUM> having a barrier, such as the barrier <NUM> shown in <FIG>. The fluid flow direction sensor <NUM> is coupled to a conduit <NUM>. In operation, the conduit <NUM> is fluidically coupled to a patient <NUM> and a ventilator <NUM>. In some embodiments, the system <NUM> includes a control system <NUM>, such as an electronic control system, to couple to the fluid flow direction sensor <NUM> to monitor the flow direction. Exemplary sensors suitable for use in connection with the system <NUM> include the sensor shown in <FIG> and described above. In some embodiments, the conduit <NUM> has an hour glass shape with the fluid flow direction sensor <NUM> is located at the narrowest point of the conduit <NUM>.

<FIG> shows a flow diagram of a method <NUM> for determining one or more fluid flow properties of a fluid flowing in a conduit in accordance with some embodiments of the present disclosure. The method <NUM> includes providing a barrier, the barrier having a first barrier surface and a second barrier surface, in the fluid to cause a difference between upstream characteristics and downstream characteristics of the fluid flowing in the conduit (block <NUM>), locating a first sensor a first distance from the first barrier surface, the first sensor to generate a first sensor signal (block <NUM>), locating a second sensor a second distance from the second barrier surface, the second sensor to generate a second sensor signal (block <NUM>), and processing the first sensor signal and the second sensor signal to determine the one or more fluid flow properties of the fluid flowing in the conduit (block <NUM>).

<FIG> shows a flow diagram of a method <NUM> for making an apparatus to determine a flow direction in a fluid in accordance with some embodiments of the present disclosure. The method <NUM> includes forming a substrate including a barrier having a first barrier surface and a second barrier surface (block <NUM>), locating a first sensor a first distance from the first barrier surface, the first sensor to generate a first sensor signal (block <NUM>), locating a second sensor a second distance from the second barrier surface, the second sensor to generate a second sensor signal (block <NUM>), and coupling the first sensor and the second sensor to the substrate, the first sensor signal and the second sensor signal to be processed to determine the flow direction in the fluid (block <NUM>).

Reference throughout this specification to "an embodiment," "some embodiments," or "one embodiment. " means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases such as "in some embodiments," "in one embodiment," or "in an embodiment," in various places throughout this specification are not necessarily referring to the same embodiment of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

Claim 1:
An apparatus (<NUM>) for use in determining one or more fluid properties of a fluid flowing in a conduit, the apparatus comprising:
a substrate (<NUM>) including a barrier (<NUM>) having a first barrier surface (<NUM>) and a second barrier surface (<NUM>);
a first flow sensor (<NUM>) to generate a first velocity sensor signal, the first flow sensor located at a first sensor distance (<NUM>) from the first barrier surface (<NUM>);
a second flow sensor (<NUM>) to generate a second velocity sensor signal, the second flow sensor (<NUM>) located at a second sensor distance (<NUM>) from the second barrier surface (<NUM>), wherein the first sensor distance (<NUM>) and the second sensor distance (<NUM>) are selected to disturb the fluid flowing in the conduit in such a way as to enable determination of the one or more fluid flow properties from the first velocity sensor signal and the second velocity sensor signal; and
a third sensor (<NUM>) for generating a signal indicative of the flow rate or flow magnitude at the third sensor (<NUM>) including a pair of third sensor conductive pins (<NUM>), the pair of third sensor conductive pins (<NUM>) embedded in the barrier (<NUM>) and the substrate (<NUM>).