Patent Description:
Thermal properties and viscosities of fluids (e.g., medication fluids, IV therapy fluids, blood, etc.) vary significantly. The variation in thermal properties and viscosities impacts an accuracy of calorimetric or dual-mode calorimetric / thermal time-of-flight flow sensors. For example, a calorimetric or dual-mode calorimetric / thermal time-of-flight flow sensor is typically calibrated for measurement with a particular fluid, and use of the calorimetric or dual-mode calorimetric / thermal time-of-flight flow sensor for measurement with a different fluid for which the flow sensor is not calibrated impacts an accuracy of a fluid flow velocity and/or a volumetric flow rate measured by the flow sensor. <CIT> describes a prior art flow sensor which measures both the thermal diffusivity of the fluid and its flow rate.

Accordingly, provided are improved systems, devices, products, apparatus, and/or methods for adjusting a fluid flow measurement.

According to a non-limiting embodiment or aspect, provided is a flow sensor comprising: a fluid flow path; a first sensor configured to determine a first measurement of at least one of a thermal diffusivity of a fluid in the fluid flow path and a viscosity of the fluid in the fluid flow path; a second sensor configured to determine a second measurement of at least one of a fluid flow velocity of the fluid in the fluid flow path and a volumetric flow rate of the fluid in the fluid flow path; at least one processor configured to adjust the second measurement based on the first measurement, wherein the second sensor is spaced apart from the first sensor in a fluid flow direction of the fluid flow path wherein the second sensor is configured to determine the second measurement based on at least one of a calorimetric mode and a thermal time-of-flight mode, and wherein the at least one processor is configured to adjust the second measurement by controlling the second sensor to switch, based on the first measurement, between (i) determining the second measurement based on only the calorimetric mode and (ii) determining the second measurement based on only the thermal time-of-flight mode.

In some non-limiting embodiments or aspects, the first sensor includes a resistive heater layer extending in a direction parallel to the fluid flow path between a first resistive temperature detector layer and a second resistive temperature detector layer extending in the direction parallel to the fluid flow path, and the second sensor includes another resistive heater layer extending in a direction perpendicular to the fluid flow path between another first resistive temperature detector layer and another second resistive temperature detector layer extending in the direction perpendicular to the fluid flow path.

In some non-limiting embodiments or aspects, a spacing between the resistive heater layer and the first resistive temperature detector layer and the second resistive temperature detector layer in the first sensor is less than a spacing between the another resistive heater layer and the another first resistive temperature detector layer and the another second resistive temperature detector layer in the second sensor.

In some non-limiting embodiments or aspects, the at least one processor is configured to adjust the second measurement by controlling the second sensor to switch, based on the first measurement, between (i) determining the second measurement based on only one of the calorimetric mode and the thermal time-of-flight mode and (ii) determining the second measurement based on each of the calorimetric mode and the thermal time-of-flight mode.

In some non-limiting embodiments or aspects, the second sensor is calibrated to determine the second measurement for a first type of the fluid, wherein the fluid includes a second type of the fluid different than the first type of the fluid, and wherein the at least one processor is configured to adjust the second measurement based on a ratio of the at least one of the thermal diffusivity of the fluid in the fluid flow path and the viscosity of the fluid in the fluid flow path to at least one of a thermal diffusivity of the first type of the fluid and a viscosity of the first type of the fluid.

In some non-limiting embodiments or aspects, the at least one processor is configured to: receive an identification of a type of the fluid to be received in the fluid flow path, wherein the identification is associated with an adjustment factor; determine, based on the first measurement, a change in the type of the fluid in the fluid flow path; and in response to determining the change in the type of the fluid in the fluid flow path, adjust the second measurement based on the adjustment factor.

In some non-limiting embodiments or aspects, the flow sensor further comprises a third sensor configured to identify the type of the fluid in the fluid flow path and provide the identification of the type of the fluid in the fluid flow path.

According to a non-limiting embodiment or aspect, provided is a method comprising: receiving fluid in a fluid flow path of a flow sensor; determining, with a first sensor of the flow sensor, a first measurement of at least one of a thermal diffusivity of the fluid in the fluid flow path and a viscosity of the fluid in the fluid flow path; determining, with a second sensor of the flow sensor, a second measurement of at least one of a fluid flow velocity of the fluid in the fluid flow path and a volumetric flow rate of the fluid in the fluid flow path; adjusting, with at least one processor, the second measurement based on the first measurement, wherein the second sensor is spaced apart from the first sensor in a fluid flow direction of the fluid flow path wherein determining the second measurement is based on at least one of a calorimetric mode of the second sensor and a thermal time-of-flight mode of the second sensor, wherein adjusting the second measurement includes controlling the second sensor to switch, based on the first measurement, between.

In some non-limiting embodiments or aspects, adjusting the second measurement includes controlling the second sensor to switch, based on the first measurement, between (i) determining the second measurement based on only one of the calorimetric mode and the thermal time-of-flight mode and (ii) determining the second measurement based on each of the calorimetric mode and the thermal time-of-flight mode.

In some non-limiting embodiments or aspects, the second sensor is calibrated to determine the second measurement for a first type of the fluid, wherein the fluid includes a second type of the fluid different than the first type of the fluid, and wherein adjusting the second measurement is based on a ratio of the at least one of the thermal diffusivity of the fluid in the fluid flow path and the viscosity of the fluid in the fluid flow path to at least one of a thermal diffusivity of the first type of the fluid and a viscosity of the first type of the fluid.

In some non-limiting embodiments or aspects, the method further comprises: receiving, with the at least one processor, an identification of a type of the fluid to be received in the fluid flow path, wherein the identification is associated with an adjustment factor; determining, with the at least one processor, based on the first measurement, a change in the type of the fluid in the fluid flow path; and in response to determining the change in the type of the fluid in the fluid flow path, adjusting, with the at least one processor, the second measurement based on the adjustment factor.

In some non-limiting embodiments or aspects, the method further comprises: identifying, with a third sensor, the type of the fluid in the fluid flow path; and providing, with the third sensor, the identification of the type of the fluid in the fluid flow path.

These and other features and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. As used in the specification and the claims, the singular form of "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

Additional advantages and details of the invention are explained in greater detail below with reference to the exemplary embodiments or aspects that are illustrated in the accompanying schematic figures, in which:.

For purposes of the description hereinafter, the terms "end," "upper," "lower," "right," "left," "vertical," "horizontal," "top," "bottom," "lateral," "longitudinal," and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments or aspects of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments or aspects of the embodiments or aspects disclosed herein are not to be considered as limiting unless otherwise indicated.

No aspect, component, element, structure, act, step, function, instruction, and/or the like used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles "a" and "an" are intended to include one or more items, and may be used interchangeably with "one or more" and "at least one. " Furthermore, as used herein, the term "set" is intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, etc.) and may be used interchangeably with "one or more" or "at least one. " Where only one item is intended, the term "one" or similar language is used. Also, as used herein, the terms "has," "have," "having," or the like are intended to be open-ended terms. Further, the phrase "based on" is intended to mean "based at least partially on" unless explicitly stated otherwise.

As used herein, the terms "communication" and "communicate" may refer to the reception, receipt, transmission, transfer, provision, and/or the like of information (e.g., data, signals, messages, instructions, commands, and/or the like). For one unit (e.g., a device, a system, a component of a device or system, combinations thereof, and/or the like) to be in communication with another unit means that the one unit is able to directly or indirectly receive information from and/or transmit information to the other unit. This may refer to a direct or indirect connection that is wired and/or wireless in nature. Additionally, two units may be in communication with each other even though the information transmitted may be modified, processed, relayed, and/or routed between the first and second unit. For example, a first unit may be in communication with a second unit even though the first unit passively receives information and does not actively transmit information to the second unit. As another example, a first unit may be in communication with a second unit if at least one intermediary unit (e.g., a third unit located between the first unit and the second unit) processes information received from the first unit and communicates the processed information to the second unit. In some non-limiting embodiments or aspects, a message may refer to a network packet (e.g., a data packet and/or the like) that includes data. It will be appreciated that numerous other arrangements are possible. It will be appreciated that numerous other arrangements are possible.

As used herein, the term "server" may refer to one or more computing devices, such as processors, storage devices, and/or similar computer components that communicate with client devices and/or other computing devices over a network, such as the Internet or private networks, and, in some examples, facilitate communication among other servers and/or client devices. It will be appreciated that various other arrangements are possible. As used herein, the term "system" may refer to one or more computing devices or combinations of computing devices such as, but not limited to, processors, servers, client devices, software applications, and/or other like components. In addition, reference to "a server" or "a processor," as used herein, may refer to a previously-recited server and/or processor that is recited as performing a previous step or function, a different server and/or processor, and/or a combination of servers and/or processors. For example, as used in the specification and the claims, a first server and/or a first processor that is recited as performing a first step or function may refer to the same or different server and/or a processor recited as performing a second step or function.

Non-limiting embodiments or aspects of the present invention are directed to systems, devices, products, apparatus, and/or methods for adjusting a fluid flow measurement. In some non-limiting embodiments or aspects, a flow sensor may include a fluid flow path; a first sensor configured to determine a first measurement of at least one of a thermal diffusivity of a fluid in the fluid flow path and a viscosity of the fluid in the fluid flow path; a second sensor configured to determine a second measurement of at least one of a fluid flow velocity of the fluid in the fluid flow path and 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. In some non-limiting embodiments or aspects, a method may include receiving fluid in a fluid flow path of a flow sensor; determining, with a first sensor of the flow sensor, a first measurement of at least one of a thermal diffusivity of the fluid in the fluid flow path and a viscosity of the fluid in the fluid flow path; determining, with a second sensor of the flow sensor, a second measurement of at least one of a fluid flow velocity of the fluid in the fluid flow path and a volumetric flow rate of the fluid in the fluid flow path; and adjusting, with at least one processor, the second measurement based on the first measurement.

In this way, a thermal property measurement and/or a viscosity measurement is used to adjust or correct calorimetric and/or thermal time-of-flight flow velocity measurements, which enables a flow sensor to more accurately determine flow velocity and/or volumetric flow rate of fluids with thermal diffusivities and/or viscosities different than that for which the flow sensor is calibrated. Accordingly, embodiments or aspects of the present invention may enable more accurate real-time measurement of dispensed volume of a fluid (e.g., dispensed volume of a medication fluid to a patient, etc.).

Referring now to <FIG> is a diagram of an example environment <NUM> in which devices, systems, and/or methods, described herein, may be implemented. As shown in <FIG>, environment <NUM> includes flow sensor <NUM>, fluid identification system <NUM>, network <NUM>, and remote system <NUM>. Flow sensor <NUM>, fluid identification system <NUM>, and remote system <NUM> may interconnect (e.g., establish a connection to communicate, etc.) via wired connections, wireless connections, or a combination of wired and wireless connections.

Flow sensor <NUM> may include fluid flow path <NUM>, first sensor <NUM>, and second sensor <NUM>. Fluid flow path <NUM> may include a wall defining a flow channel for fluid. For example, fluid flow path <NUM> may include a cylindrical flow path having a radius R, a flow path with a square cross-section, a flow path with a rectangular cross-section, and/or the like. In some non-limiting embodiments or aspects, first sensor <NUM> and/or second sensor <NUM> are located within fluid flow path <NUM>. For example, first sensor <NUM> and/or second sensor <NUM> can be connected to an inside surface of the wall defining the flow channel of fluid flow path <NUM> (e.g., at an edge of the flow channel, etc.). First sensor <NUM> and second sensor <NUM> may interconnect (e.g., establish a connection to communicate, etc.) via a wired connection, a wireless connection, or a combination of a wired and a wireless connection.

According to the invention, second sensor <NUM> is spaced apart from first sensor <NUM> in a fluid flow direction of fluid flow path <NUM>. For example, in an implementation of a non-limiting embodiment or aspect of flow sensor <NUM> in which fluid flows from left to right in fluid flow path <NUM> as shown in <FIG>, second sensor <NUM> may be located to the right of first sensor <NUM>. As an example, fluid in fluid flow path <NUM> may flow over or past first sensor <NUM> before the fluid in fluid flow path <NUM> flows over or past second sensor <NUM>.

First sensor <NUM> may include one or more devices capable of receiving information from and/or communicating information to second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> via network <NUM>. In some non-limiting embodiment or aspects, first sensor <NUM> is configured to determine a first measurement of at least one of a thermal diffusivity of a fluid in fluid flow path <NUM> and a viscosity of the fluid in fluid flow path <NUM>.

In some non-limiting embodiments or aspects, first sensor <NUM> includes a thermal diffusivity measurement sensor or chip configured to measure a thermal diffusivity of a fluid in fluid flow path <NUM>. For example, in an implementation of a non-limiting embodiment or aspect of flow sensor <NUM> as shown in <FIG>, first sensor <NUM> may include a resistive heater (RH) layer extending in a direction parallel to fluid flow path <NUM> between a first resistive temperature detector (RTD) layer or thermopile and a second RTD layer or thermopile extending in the direction parallel to fluid flow path <NUM> (e.g., a RH layer equally spaced from the first RTD layer and the second RTD layer, etc.). As an example, first sensor <NUM> can pulse, modulate, or continuously operate the RH layer and sense or measure a temperature with the RTD layers or thermopiles to determine the first measurement including the thermal diffusivity of a fluid in fluid flow path <NUM> (e.g., to provide a signal which is interpreted to determine the thermal diffusivity, etc.). In such an example, first sensor <NUM> may be located in a substantially no-flow environment within fluid flow path <NUM> due to first sensor <NUM> (e.g., the RH layer and first and second RTD layers of first sensor <NUM>, etc.) being oriented parallel to the flow of the fluid, which enables a heat pulse from the RH layer to transfer to and/or be detected by the first and second RTD layers or thermophiles before the flow of the fluid in fluid flow path <NUM> carries the heat pulse beyond or past the first and second RTD layers or thermopiles of first sensor <NUM>.

In some non-limiting embodiments or aspects, first sensor <NUM> includes an in situ fluid thermal property measurement apparatus configured to measure a thermal diffusivity of a fluid in fluid flow path <NUM>, such as a transient hot wire thermal conductivity measurement sensor, a bridge-based micromachined sensor, a transient hot-strip sensor, and/or the like as described in <NPL>; <NPL>); and<NPL>), each of which is hereby incorporated by reference in its entirety.

In some non-limiting embodiments or aspects, first sensor <NUM> includes a viscosity measurement sensor or chip configured to measure a viscosity of a fluid in fluid flow path <NUM>. For example, first sensor <NUM> may include a MEMs viscosity measurement sensor or chip, such as described in <NPL>, the entire contents of which is hereby incorporated by reference.

Second sensor <NUM> may include one or more devices capable of receiving information from and/or communicating information to first sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> via network <NUM>. In some non-limiting embodiments or aspects, second sensor <NUM> is configured to determine a second measurement of at least one of a fluid flow velocity of the fluid in fluid flow path <NUM> and a volumetric flow rate of the fluid in the fluid flow path <NUM>. In some non-limiting embodiments or aspects, second sensor <NUM> is calibrated to determine the second measurement for a first type of the fluid, and the fluid in fluid flow path <NUM> includes a second type of the fluid different than the first type of the fluid. In some non-limiting embodiments or aspects, second sensor <NUM> is configured to receive the first measurement from first sensor <NUM> and adjust the second measurement based on the first measurement. In some non-limiting embodiments or aspects, first sensor <NUM> is configured to receive the second measurement from second sensor <NUM> and adjust the second measurement based on the first measurement.

In some non-limiting embodiments or aspects, second sensor <NUM> includes a calorimetric or dual-mode calorimetric / thermal time-of-flight sensor or chip. For example, second sensor <NUM> may include a MEMS time-of-flight thermal mass flow meter as described in <CIT>, and/or a MEMs device as described in <NPL>, the entire contents of each of which is hereby incorporated by reference. As an example, referring again to <FIG>, second sensor <NUM> may include a RH layer extending in a direction perpendicular to fluid flow path <NUM> between a first RTD layer or thermopile and a second RTD layer or thermopile extending in the direction perpendicular to fluid flow path <NUM>. In such an example, second sensor <NUM> can pulse, modulate, or continuously operate the RH layer and sense or measure a temperature variation with the RTD layers or thermopiles to determine the second measurement of at least one of a fluid flow velocity of the fluid in fluid flow path <NUM> and a volumetric flow rate of the fluid in the fluid flow path <NUM> (e.g., to provide a signal which is interpreted to determine the fluid flow velocity and/or the volumetric flow rate, etc.) according to the calibration of second sensor <NUM>.

In some non-limiting embodiments or aspects, as shown in <FIG>, a spacing between the RH layer and the first RTD layer and the second RTD layer in first sensor <NUM> is less than a spacing between the RH layer and the first RTD layer and the second RTD layer in second sensor <NUM>. For example, use of calorimetric or dual-mode calorimetric / thermal time-of-flight sensors or chips as described herein for calorimetric mode flow measurement technology functions demonstrates that these calorimetric sensors or chips have a sufficient sensitivity to measure a thermal diffusivity at a substantially zero flow as described herein. As an example, a calorimetric or dual-mode calorimetric / thermal time-of-flight sensor or chip configured or implemented as a thermal diffusivity measurement chip (e.g., as first sensor <NUM>) may have a significantly smaller spacing between the RH layer and the RTD layers or thermopiles than a calorimetric or dual-mode calorimetric / thermal time-of-flight sensor or chip configured or implemented as a flow velocity measurement chip (e.g., as second sensor <NUM>).

Fluid identification system <NUM> may include one or more devices capable of receiving information from and/or communicating information to first sensor <NUM>, second sensor <NUM>, and/or remote system <NUM> via network <NUM>. In some non-limiting embodiments or aspects, fluid identification system <NUM> includes a fluid identification sensor configured to identify a type of a fluid in fluid flow path <NUM> and provide an identification of the type of the fluid in fluid flow path <NUM>. In some non-limiting embodiments or aspects, fluid identification system <NUM> is incorporated or implemented in flow sensor <NUM>. For example, flow sensor <NUM> may include a fluid identification sensor configured to identify a type of fluid in fluid flow path <NUM> and provide an identification of the type of the fluid in fluid flow path <NUM>.

Network <NUM> may include one or more wired and/or wireless networks. For example, network <NUM> may include a cellular network (e.g., a long-term evolution (LTE) network, a third generation (<NUM>) network, a fourth generation (<NUM>) network, a code division multiple access (CDMA) network, etc.), a public land mobile network (PLMN), a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), a telephone network (e.g., the public switched telephone network (PSTN)), a private network, an ad hoc network, an intranet, the Internet, a fiber optic-based network, a cloud computing network, a short range wireless communication network (e.g., a Bluetooth network, a near field communication (NFC) network, etc.) and/or the like, and/or a combination of these or other types of networks.

Remote system <NUM> may include one or more devices capable of receiving information from and/or communicating information to first sensor <NUM>, second sensor <NUM>, and/or fluid identification system <NUM> via network <NUM>. In some non-limiting embodiments or aspects, remote system <NUM> is in communication with a data storage device, which may be local or remote to remote system <NUM>. In some non-limiting embodiments or aspects, remote system <NUM> is capable of receiving information from, storing information in, communicating information to, or searching information stored in the data storage device. In some non-limiting embodiments or aspects, remote system <NUM> is configured to receive the first measurement from first sensor <NUM> and the second measurement from second sensor <NUM> and adjust the second measurement based on the first measurement.

There may be additional devices and/or networks, fewer devices and/or networks, different devices and/or networks, or differently arranged devices and/or networks than those shown in <FIG>.

Referring now to <FIG> is a diagram of example components of a device <NUM>. Device <NUM> may correspond to one or more devices of flow sensor <NUM>, one or more devices of first sensor <NUM>, one or more devices of second sensor <NUM>, one or more devices of fluid identification system <NUM>, and/or one or more devices of remote system <NUM>. In some non-limiting embodiments or aspects, flow sensor <NUM>, first sensor <NUM>, second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> can include at least one device <NUM> and/or at least one component of device <NUM>. As shown in <FIG>, device <NUM> may include a bus <NUM>, a processor <NUM>, memory <NUM>, a storage component <NUM>, an input component <NUM>, an output component <NUM>, and a communication interface <NUM>.

Bus <NUM> may include a component that permits communication among the components of device <NUM>. In some non-limiting embodiments or aspects, processor <NUM> may be implemented in hardware, firmware, or a combination of hardware and software. For example, processor <NUM> may include a processor (e.g., a central processing unit (CPU), a graphics processing unit (GPU), an accelerated processing unit (APU), etc.), a microprocessor, a digital signal processor (DSP), and/or any processing component (e.g., a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), etc.) that can be programmed to perform a function. Memory <NUM> may include random access memory (RAM), read only memory (ROM), and/or another type of dynamic or static storage device (e.g., flash memory, magnetic memory, optical memory, etc.) that stores information and/or instructions for use by processor <NUM>.

Input component <NUM> may include a component that permits device <NUM> to receive information, such as via user input (e.g., a touch screen display, a keyboard, a keypad, a mouse, a button, a switch, a microphone, etc.). Additionally, or alternatively, input component <NUM> may include a sensor for sensing information (e.g., a global positioning system (GPS) component, an accelerometer, a gyroscope, an actuator, etc.). Output component <NUM> may include a component that provides output information from device <NUM> (e.g., a display, a speaker, one or more light-emitting diodes (LEDs), etc.).

Communication interface <NUM> may include a transceiver-like component (e.g., a transceiver, a separate receiver and transmitter, etc.) that enables device <NUM> to communicate with other devices, such as via a wired connection, a wireless connection, or a combination of wired and wireless connections. Communication interface <NUM> may permit device <NUM> to receive information from another device and/or provide information to another device. For example, communication interface <NUM> may include an Ethernet interface, an optical interface, a coaxial interface, an infrared interface, a radio frequency (RF) interface, a universal serial bus (USB) interface, a Wi-Fi® interface, a cellular network interface, and/or the like.

Device <NUM> may perform one or more processes described herein. Device <NUM> may perform these processes based on processor <NUM> executing software instructions stored by a computer-readable medium, such as memory <NUM> and/or storage component <NUM>. A computer-readable medium (e.g., a non-transitory computer-readable medium) is defined herein as a non-transitory memory device. A memory device includes memory space located inside of a single physical storage device or memory space spread across multiple physical storage devices.

Thus, embodiments or aspects described herein are not limited to any specific combination of hardware circuitry and software.

Referring now to <FIG> is a flowchart of a non-limiting embodiment or aspect of a process <NUM> for adjusting a fluid flow measurement. In some non-limiting embodiments or aspects, one or more of the steps of process <NUM> may be performed (e.g., completely, partially, etc.) by flow sensor <NUM> (e.g., one or more devices of flow sensor <NUM>, such as first sensor <NUM>, second sensor <NUM>, and/or the like). In some non-limiting embodiments or aspects, one or more of the steps of process <NUM> may be performed (e.g., completely, partially, etc.) by another device or a group of devices separate from or including flow sensor <NUM>, such as fluid identification system <NUM> (e.g., one or more devices of fluid identification system <NUM>) and/or remote system <NUM> (e.g., one or more devices of remote system <NUM>).

As shown in <FIG>, at step <NUM>, process <NUM> includes receiving fluid in a fluid flow path of a flow sensor. For example, flow sensor <NUM> receives fluid in fluid flow path <NUM>. As an example, the fluid in the fluid flow path may include a medication fluid, an IV therapy fluid, blood, and/or the like.

As further shown in <FIG>, at step <NUM>, process <NUM> includes determining a first measurement of at least one of a thermal diffusivity of the fluid in the fluid flow path and a viscosity of the fluid in the fluid flow path. For example, first sensor <NUM> determines a first measurement of at least one of a thermal diffusivity of the fluid in fluid flow path <NUM> and a viscosity of the fluid in fluid flow path <NUM>. As an example, first sensor <NUM> senses or measures at least one of a thermal diffusivity of the fluid in fluid flow path <NUM> and a viscosity of the fluid in fluid flow path <NUM>.

In some non-limiting embodiments or aspects, first sensor <NUM> measures a thermal diffusivity of the fluid in fluid flow path <NUM>, which is a relevant parameter for calibration of a calorimetric or dual-mode calorimetric / thermal time-of-flight sensor or chip. Thermal diffusivity α of a fluid may be defined according to the following Equation (<NUM>): <MAT> where k = thermal conductivity (e.g., W/m K) , ρ = density (e.g., kg/m<NUM>), and Cp = specific heat capacity (e.g., J/kg K). For example, a model of an impact of a variation in thermal diffusivity on an accuracy of thermal flow sensors is described in Steven Bindels, "Dependency of the Thermal Fluid Properties on Fluid Flow Sensor", report on Masters Internship at Philips Research, BMTE <NUM> Eindhoven University of Technology and Philips-Eindhoven. Eindhoven, The Netherlands. Nov <NUM> (hereinafter "Bindels"), the entire contents of which is hereby incorporated by reference.

In some non-limiting embodiments or aspects, first sensor measures a viscosity of the fluid in fluid flow path <NUM>, which is a relevant parameter for calibration of a calorimetric or dual-mode calorimetric / thermal time-of-flight sensor or chip. Viscosity of a fluid may be defined as described herein below in more detail with respect to <FIG>. For example, a model of an impact of a variation in viscosity on an accuracy of thermal flow sensors is described Bindels.

In some non-limiting embodiments or aspects, first sensor <NUM> provides the first measurement to second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM>, and second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> receives the first measurement from first sensor <NUM>.

As further shown in <FIG>, at step <NUM>, process <NUM> includes determining a second measurement of at least one of a fluid flow velocity of the fluid in the fluid flow path and a volumetric flow rate of the fluid in the fluid flow path. For example, second sensor <NUM> determines a second measurement of at least one of a fluid flow velocity of the fluid in fluid flow path <NUM> and a volumetric flow rate of the fluid in fluid flow path <NUM>. As an example, second sensor <NUM> senses or measures at least one of a fluid flow velocity of the fluid in fluid flow path <NUM> and a volumetric flow rate of the fluid in fluid flow path <NUM>.

According to the invention, determining the second measurement is based on at least one of a calorimetric mode of second sensor <NUM> and a thermal time-of-flight mode of second sensor <NUM>. For example, second sensor <NUM> measures at least one of a fluid flow velocity of the fluid in fluid flow path <NUM> and a volumetric flow rate of the fluid in fluid flow path <NUM> in at least one of a calorimetric mode (e.g., using calorimetric measurements and/or properties, etc.) and a thermal time-of-flight mode (e.g., using thermal time-of-flight measurements and/or properties, etc.).

In some non-limiting embodiments or aspects, second sensor <NUM> provides the second measurement to first sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM>, and first sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> receives the second measurement from second sensor <NUM>.

As further shown in <FIG>, at step <NUM>, process <NUM> includes adjusting the second measurement based on the first measurement. For example, first sensor <NUM>, second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> adjusts the second measurement based on the first measurement. As an example, first sensor <NUM>, second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> adjusts the second measurement based on the first measurement in real-time (e.g., during the flow of the fluid in fluid flow path <NUM> from which the first measurement and the second measurement are determined, etc.).

In some non-limiting embodiments or aspects, a calibration accuracy of second sensor <NUM> (e.g., an accuracy of flow rate measurements by second sensor <NUM>, etc.) is impacted to varying degrees by differences in thermal diffusivity and viscosity between the fluid in fluid flow path <NUM> (e.g., a fluid under test, etc.) and a particular fluid with which second sensor <NUM> is calibrated. As an example, if second sensor <NUM> is calibrated for flow measurement with a particular fluid (e.g. water, a first type of medication fluid, etc.) and flow measurement of a different fluid (e.g., a medication fluid, a different type of medication fluid, etc.) is desired or performed, the flow measurement calibration of second sensor <NUM> can be adjusted or corrected by using the thermal diffusivity measurement and/or the viscosity measurement of the fluid in fluid flow path <NUM> measured by first sensor <NUM> to adjust or correct a fluid flow velocity measurement and/or a volumetric flow rate measurement of the fluid in the fluid flow path <NUM> measured by second sensor <NUM>. In such an example, the second measurement by second sensor <NUM> can be adjusted based on a ratio of the at least one of the thermal diffusivity of the fluid in fluid flow path <NUM> (e.g., the fluid under test, etc.) and the viscosity of the fluid in fluid flow path <NUM> (e.g., the fluid under test, etc.) to at least one of a thermal diffusivity of the particular calibration fluid and a viscosity of the particular calibration fluid.

In some non-limiting embodiments or aspects, a fluid flow velocity of the fluid in fluid flow path <NUM> and/or a volumetric flow rate of the fluid in the fluid flow path <NUM> measured by second sensor <NUM> is adjusted or corrected based on one or more theoretical models of an impact of thermal properties of fluids on flow rate measurements by calorimetric or dual-mode calorimetric / thermal time-of-flight flow sensors as described in <NPL>;<NPL>; and <CIT>, each of which is hereby incorporated by reference in its entirety. For example, one or more of these described models of the impact of thermal properties of fluids on flow rate measurements can be applied to implement an adjustment or correction in the second measurement from second sensor <NUM> (e.g., an adjustment or correction to a volumetric flow rate measurement received from second sensor <NUM>, an adjustment or correction in flow sensor firmware/software of second sensor <NUM> used to determine and/or process the second measurement, etc.) based upon a ratio of the thermal diffusivity (and/or thermal conductivity) of the fluid in fluid flow path <NUM> (e.g., the fluid under test) to the thermal diffusivity (and/or thermal conductivity) of the particular fluid for which the second sensor <NUM> is calibrated. In such an example, an impact of physical properties of a fluid on the flow measurement process of calorimetric and thermal time-of-flight flow sensors, which can be applied to adjust a fluid flow velocity of the fluid in fluid flow path <NUM> and/or a volumetric flow rate of the fluid in the fluid flow path <NUM> measured by second sensor <NUM>, is described in sections <NUM>. <NUM> and <NUM>. <NUM> of<NPL>) (hereinafter "Kuo"), the entire contents of which is hereby incorporated by reference. In some non-limiting embodiments, an impact of a boundary layer thickness, which is a function of viscosity, for a calorimetric flow sensor, which is described in in section <NUM>. <NUM> of Kuo, can be applied to adjust a fluid flow velocity of the fluid in fluid flow path <NUM> and/or a volumetric flow rate of the fluid in the fluid flow path <NUM> measured by second sensor <NUM>.

In some non-limiting embodiment or aspects, a fluid flow velocity of the fluid in fluid flow path <NUM> and/or a volumetric flow rate of the fluid in the fluid flow path <NUM> measured by second sensor <NUM> is adjusted or corrected based on one or more fluid mechanics principles applied to implement an adjustment or correction in the second measurement by second sensor <NUM> (e.g., an adjustment or correction to a volumetric flow rate measurement received from second sensor <NUM>, an adjustment or correction in flow sensor firmware/software of second sensor <NUM>, etc.) based on a viscosity of the fluid in fluid flow path <NUM> (e.g., the fluid under test) measured by first sensor <NUM>. For example, second sensor <NUM>, such as a thermal flow sensor (e.g., a calorimetric and/or thermal time-of-flight flow sensor, etc.) may measure flow velocity at a point relatively far from a center of a flow channel (which may be cylindrical or of square, rectangular or other cross section) and provide a volumetric flow rate via a calibration which is performed for a particular calibration fluid. As an example, in a more simple case of fully developed laminar flow in a cylindrical flow path, as shown in <FIG> and discussed in more detail herein below, the laminar flow velocity profile is a parabolic function of radial position from the center of the flow channel or "pipe" (e.g., the cylindrical flow sensor's region of flow sensing, etc.) and the flow velocity at the position of the flow sensor MEMS chip surface, the mean and maximum flow velocity, and the volumetric flow rate are linearly related by the viscosity of the fluid. Thus, when a volumetric flow rate of a fluid other than that for which the sensor is calibrated is desired or measured, the measured viscosity from the MEMS viscosity sensor (e.g., first sensor <NUM>, etc.) can be used to linearly adjust the volumetric flow rate measurement by the flow sensor (e.g., second sensor <NUM>, etc.) via a viscosity ratio of the fluid being measured and the calibration fluid according to equations defined below with respect to <FIG>.

Referring now to <FIG> is a diagram of a non-limiting embodiment or aspect of an ideal parabolic laminar flow velocity profile in a fluid flow path of a flow sensor of <FIG>. As shown in <FIG>, an ideal parabolic laminar flow velocity profile may exist in well-developed laminar flow in a pipe or tubing (e.g., in a cylindrical flow path) of radius R. Second sensor <NUM> may be configured to measure a flow velocity at a surface of second sensor <NUM> at radial position r = Rsensor. Due to a no-slip velocity condition, second sensor <NUM> may not be flush with the wall of fluid flow path <NUM>. A flow velocity V(Rsensor) measured at second sensor <NUM> at radial position r = Rsensor can be correlated to a maximum flow velocity Vmax = V(<NUM>) observed at r = <NUM> and to a volumetric flow rate through the pipe or tubing. A flow velocity profile for fully developed laminar flow in the pipe of radius R can be defined according to the following Equation (<NUM>): <MAT> where Vmax = <NUM> * Vavg, Vavg = an average flow velocity of the laminar flow, Vmax = [(a pressure drop along a length L of the pipe) * R<NUM> / <NUM> * (viscosity) * (L) and is a centerline velocity of the laminar flow, and a volumetric flow rate Q for the fully developed laminar flow in the pipe of radius R can be defined according to the following Equation (<NUM>): <MAT>.

In some non-limiting embodiments or aspects, if second sensor <NUM> (e.g., a MEMS thermal flow sensor chip, etc.) is located in an area or zone of fluid flow path <NUM> at which laminar flow is not fully developed (e.g., within a entrance length region where a velocity boundary layer exists, etc.) mathematics of the relationship between the measured fluid viscosity, the measured fluid velocity at the surface of the MEMS thermal flow sensor chip, and an adjustment or correction to the volumetric flow rate relative to the volumetric flow rate the flow sensor calculates based upon its calibration with a fluid of a different viscosity than the fluid flowing through fluid flow path <NUM> are more complicated than in the ideal laminar flow case described herein with respect to <FIG>, but the concept of an adjustment or correction mechanism based on a viscosity measurement is similar and not described herein in detail in the interest of brevity.

In some non-limiting embodiments or aspects, a fluid flow velocity of the fluid in fluid flow path <NUM> and/or a volumetric flow rate of the fluid in the fluid flow path <NUM> measured by second sensor <NUM> is adjusted or corrected based a combination of a thermal property measurement by first sensor <NUM> and a viscosity measurement by first sensor <NUM>. For example, first sensor <NUM> may include a thermal property MEMs chip and a viscosity measurement MEMs chip. As an example, a fluid flow velocity of the fluid in fluid flow path <NUM> and/or a volumetric flow rate of the fluid in the fluid flow path <NUM> measured by second sensor <NUM> can be adjusted or corrected based on the thermal diffusivity ratios and the viscosity ratios between the fluid under test and the calibration fluid as described herein and/or one or more models of an impact of physical properties of a fluid on a flow measurement process of calorimetric and/or thermal time-of-flight sensors as described in Kuo.

According to the invention, adjusting the second measurement includes controlling second sensor <NUM> to switch, based on the first measurement, between (i) determining the second measurement based on only the calorimetric mode and (ii) determining the second measurement based on only the thermal time-of-flight mode. In some non-limiting embodiment or aspects, adjusting the second measurement includes controlling second sensor <NUM> to switch, based on the first measurement, between (i) determining the second measurement based on only one of the calorimetric mode and the thermal time-of-flight mode and (ii) determining the second measurement based on each of the calorimetric mode and the thermal time-of-flight mode. For example, measured thermal properties of the fluid and/or measured viscosity of the fluid can be used to determine an appropriate point in time to switch from utilization of a calorimetric mode to utilization of a thermal time-of-flight mode for a dual mode sensor if only one of these modes is used to determine a flow rate measurement at a time, or to combine information from these two modes in a fashion which calculates a more accurate flow velocity and volumetric flow rate passing through flow sensor <NUM>. The determination of the switch point and/or volumetric flow rate adjustment or correction can be based upon empirical data/measurements of impact of differences between the thermal diffusivity (and/or thermal conductivity) of the fluid under test relative to the thermal diffusivity (and/or thermal conductivity) of the flow sensor calibration fluid and/or viscosity of the fluid under test relative to the viscosity of the flow sensor calibration fluid on volumetric flow rate measurement (of either a calorimetric only mode flow sensor or a dual mode calorimetric/thermal time-of-flight thermal flow sensor), and an optimal switch point between the calorimetric and thermal-time-of-flight modes for a dual mode thermal flow sensor.

In some non-limiting embodiments or aspects, flow sensor <NUM> and/or remote system <NUM> provides adjusted data as output via output component <NUM>, (e.g., via a display of the adjusted second measurement, etc.), wherein the adjusted data is based on the adjusted second measurement. In some non-limiting embodiments or aspects, first sensor <NUM>, second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> controls delivery of the fluid to and/or from flow sensor <NUM> (and/or to and/or from another fluid delivery device through which the fluid flows, to and/or from a patient, etc.) based on the adjusted second measurement. For example, first sensor <NUM>, second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> controls one or more valves and/or one or more fluid delivery pumps to modify the flow of the fluid in fluid flow path <NUM> based on the adjusted second measurement.

Further details regarding step <NUM> of process <NUM> are provided below with regard to <FIG>.

As shown in <FIG>, at step <NUM>, process <NUM> includes receiving an identification of a type of the fluid to be received in the fluid flow path. For example, first sensor <NUM>, second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> receives an identification of a type of fluid to be received in fluid flow path <NUM>. In some non-limiting embodiments or aspects, the identification is associated with an adjustment factor. For example, an adjustment factor may include a predetermined adjustment or correction to be applied to a fluid flow velocity of the fluid in fluid flow path <NUM> and/or a volumetric flow rate of the fluid in the fluid flow path <NUM> measured by second sensor <NUM> for the type of the identified fluid. As an example, the adjustment factor may be based on previous empirically based or theoretical calculation/modeling based determinations for measurement of the identified type of fluid in flow sensor <NUM>.

In some non-limiting embodiments or aspects, fluid identification system <NUM> identifies the type of fluid to be received and/or currently in fluid flow path <NUM> and provides the identification of the type of fluid to first sensor <NUM>, second sensor <NUM>, and/or remote system <NUM>.

As further shown in <FIG>, at step <NUM>, process <NUM> includes determining, based on the first measurement, a change in the type of the fluid in the fluid flow path. For example, first sensor <NUM>, second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM> determines, based on the first measurement, a change in the type of fluid in fluid flow path <NUM>. As an example, flow sensor <NUM> can be used in a dynamic manner with multiple different types of fluid passing through flow sensor <NUM> and a thermal diffusivity measurement and/or a viscosity measurement by first sensor <NUM> (e.g., a change in the thermal diffusivity measurement and/or the viscosity measurement that satisfies one or more thresholds, etc.) can be used to determine that a different or new fluid is entering fluid flow path <NUM> (e.g., a flow sensing area or region of fluid flow path <NUM> including second sensor <NUM>, etc.). In such an example, the identification associated with the adjustment factor for the different or new fluid can be used to alert flow sensor <NUM> that a change in the type of the fluid in the fluid flow path is about to occur, and the measured thermal diffusivity change (and/or thermal conductivity change) and/or the measured viscosity change from first sensor <NUM> can be used by flow sensor <NUM> to identify the particular point in time at which the fluid front of the different or new fluid has entered fluid flow path <NUM> (e.g., the flow sensing area or region, etc.).

As further shown in <FIG>, at step <NUM>, process <NUM> includes, in response to determining the change in the type of the fluid in the fluid flow path, adjusting the second measurement based on the adjustment factor. For example, first sensor <NUM>, second sensor <NUM>, fluid identification system <NUM>, and/or remote system <NUM>, in response to determining the change in the type of the fluid in fluid flow path <NUM>, adjusts the second measurement based on the adjustment factor. As an example, in response to the measured thermal diffusivity change (and/or thermal conductivity change) and/or the measured viscosity change from first sensor <NUM>, second sensor <NUM> can apply an appropriate empirical and/or theoretical volumetric flow rate measurement adjustment or correction for the new or different fluid that has entered fluid flow path <NUM> based on the adjustment factor associated with the new or different fluid. In such an example, second sensor <NUM> (e.g., a dual-mode calorimetric / thermal time-of-flight flow sensor, etc.) may have different optimal switch points between calorimetric and thermal time-of-flight operation modes for fluids of different thermal diffusivities and/or different viscosities to maximize or optimize volumetric flow rate measurement performance (e.g., an accuracy of flow measurements, a response time of flow measurements, etc.) As an example, the thermal diffusivity measurement and/or the viscosity measurement can be combined with the adjustment factor to determine a calorimetric/time-of-flight mode switch point for second sensor <NUM> for the new or different fluid from previous empirically based or theoretical calculation/modeling based determinations of what that thermal optimum flow sensor measurement mode switch point would be for that particular fluid (e.g., if exact fluid identity is known) or for a fluid of that particular thermal diffusivity (and/or thermal conductivity) and/or viscosity.

Claim 1:
A flow sensor (<NUM>) comprising:
a fluid flow path (<NUM>);
a first sensor (<NUM>) configured to determine a first measurement of at least one of a thermal diffusivity of a fluid in the fluid flow path (<NUM>) and a viscosity of the fluid in the fluid flow path (<NUM>);
a second sensor (<NUM>) configured to determine a second measurement of at least one of a fluid flow velocity of the fluid in the fluid flow path (<NUM>) and a volumetric flow rate of the fluid in the fluid flow path (<NUM>); and
at least one processor (<NUM>) configured to adjust the second measurement based on the first measurement,
wherein the second sensor (<NUM>) is spaced apart from the first sensor (<NUM>)
in a fluid
flow direction of the fluid flow path (<NUM>),
wherein the second sensor (<NUM>) is configured to determine the second measurement based on at least one of a calorimetric mode and a thermal time-of-flight mode,
characterized in that
the at least one processor (<NUM>) is configured to adjust the second measurement by controlling the second sensor (<NUM>) to switch, based on the first measurement, between (i) determining the second measurement based on only the calorimetric mode and (ii) determining the second measurement based on only the thermal time-of-flight mode.