Flow detector

Abstract

In some examples, a flow detector includes one or more bodies positioned within a flow path for a fluid flow. The one or more bodies define at least one stagnation feature configured to cause movement of the fluid flow as the fluid flows within the flow path. The flow detector includes processing circuitry configured to determine a frequency of the movement of the fluid flow and determine a flow rate of the fluid flow using the frequency. In some examples, the flow detector is configured to determine an amount of fluid delivered to a container configured to hold a medical solution comprising the fluid flow. In some examples, the flow detector is included in a system configured to produce the medical solution.

Description

Docket No : A0009202 PCT01 / 1246-061 WOO 1FLOW DETECTOR

[0001] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 687,018, filed August 26, 2024, which is entitled “FLOW DETECTOR” and is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] The disclosure relates to generation of a medical solution.BACKGROUND

[0003] Dialysis machines may be used to remove waste products from blood of a patient when the kidneys of the patient are no longer able to adequately do so. During dialysis, the dialysis machine may generate or regenerate dialysate using specified concentrations of solute buffers, osmotic agents, cations, and other concentrates for biocompatibility with the patient. The dialysis machine may provide the dialysate to a cycler for delivery to the patient. For example, the cycler may deliver the dialysate through a catheter into a peritoneal cavity of the patient. Toxins and metabolic waste products are exchanged from the blood of the patient to the dialysate. The dialysate including the toxins and waste products may be removed from the patient.SUMMARY

[0004] The present disclosure describes example devices, systems, and methods for the preparation of peritoneal dialysis fluid. In some examples, a system includes one or more containers holding one or more components of the peritoneal dialysis fluid (“PDF components”) in solid or concentrated liquid form. The one or more containers may be configured to receive a fluid (e.g., purified water) to cause dissolution and / or dilution of one or more PDF components, in order to produce a medical solution comprising the peritoneal dialysis fluid within the container. In examples, the system is configured to receive the fluid (e.g., water) from a water source available in a patient’s home, such that the patient or a caregiver may fluidly couple the system to the water source to produce the medical solution. The system includes a flow detector configured to determine a flow rate and / or fluid amount of the fluid provided to produce the medical solution. Hence, the system may allow a patient or caregiver to use the system to produce the medical solution, such that a container holding only the PDF component (e.g., a solid concentrate or a liquid concentrate) may be deliveredDocket No : A0009202 PCT01 / 1246-061 WOO 1 to the patient or caregiver, and the patient or caregiver can prepare the peritoneal dialysis fluid at home. This may reduce handling, storage, and delivery burdens on the patient or caregiver compared to systems which require delivery of fully mixed medical solutions and / or peritoneal dialysis solutions.

[0005] In an example, a system comprises: a conduit including a conduit wall defining a flow path for a fluid flow; a container configured to receive a fluid from the conduit, wherein the container is configured to hold a mixture of the fluid and a material; a flow detector including one or more bodies within the flow path, wherein the conduit is configured to cause the fluid flow to flow around the one or more bodies when the fluid flow flows within the flow path, and wherein the one or more bodies define a stagnation feature configured to cause a first portion of the fluid flow to divert from a second portion of the fluid flow when the fluid flow encounters the stagnation feature; a sensor configured to sense a movement in the fluid caused by vortex shedding of the fluid when the fluid flows around the one or more bodies, wherein the sensor is configured to sense the movement at a location downstream of the stagnation feature; a pump configured to cause the fluid flow to flow through the flow path at a flowrate causing the fluid flow to have a Reynolds number of less than or equal to about 9000 within the flow path; and processing circuitry configured to: receive a signal indicative of the movement from the sensor, determine a frequency of the movement using the signal, determine a flow rate of the fluid flow within the conduit based on the frequency, and determine an amount of the fluid delivered to the container based on the flow rate of the fluid flow.

[0006] In an example, a system comprises: a conduit including a conduit wall defining a flow path for a fluid flow; a container configured to receive a fluid from the conduit, wherein the container is configured to hold a mixture of the fluid and a material; a flow detector including one or more bodies within the flow path, wherein the conduit is configured to cause the fluid flow to flow around the one or more bodies when the fluid flow flows within the flow path, and wherein the one or more bodies define a stagnation feature configured to cause a first portion of the fluid flow to divert from a second portion of the fluid flow when the fluid flow encounters the stagnation feature; a sensor configured to sense a movement in the fluid caused by vortex shedding of the fluid when the fluid flows around the one or more bodies, wherein the sensor is configured to sense the movement at a location downstream of the stagnation feature; a pump configured to cause the fluid flow to flow through the flow path at a flowrate causing the fluid flow to have a Reynolds number of less than or equal to about 9000 within the flow path; and processing circuitry configured to: receive a signalDocket No : A0009202 PCT01 / 1246-061 WOO 1 indicative of the movement from the sensor, determine a frequency of the movement using the signal, determine a flow rate of the fluid flow within the conduit based on the frequency, and determine an amount of the fluid delivered to the container based on the flow rate of the fluid flow.

[0007] In an example, a method comprises: receiving, by processing circuitry, a signal indicative of movement of a fluid flow from a sensor, wherein the movement is caused by vortex shedding of fluid flow when the fluid flows around a first body and around a second body within a flow path defined by a conduit, wherein the fluid flow has a Reynolds number less than or equal to about 9000 within the conduit, and wherein the sensor senses the movement at a location downstream of a stagnation feature of the second body, the stagnation feature configured to cause a stagnation point in the fluid flow when the fluid flows around the second body, and determining, by the processing circuitry, a frequency of the movement; and determining, by the processing circuitry, a flow rate of the fluid flow within the flow path based on the frequency.

[0008] In an example, a system comprises: a conduit including a conduit wall defining a flow path for a fluid flow of a fluid; a flow detector including one or more bodies within the flow path, wherein the conduit is configured to cause the fluid flow to flow around the one or more bodies when the fluid flow flows within the flow path, and wherein the one or more bodies define a stagnation feature; a sensor configured to sense a movement in the fluid when the fluid flows around the one or more bodies, wherein the sensor is configured to sense the movement at a location downstream of the stagnation feature; and processing circuitry configured to: receive a signal indicative of the movement from the sensor, determine a frequency of the movement using the signal, determine a flow rate of the fluid flow within the conduit based on the frequency, and determine an amount of the fluid delivered to a container based on the flow rate of the fluid flow.

[0009] In an example, a flow detector comprises: a conduit including a conduit wall defining a flow path for a fluid flow; a first body defining a first obstacle within the flow path; a second body defining a second obstacle within the flow path, wherein the conduit is configured to cause the fluid flow to flow around the first body and the second body when the fluid flow flows within the flow path, and a sensor configured to sense a movement in the fluid of the fluid flow when the fluid flows around the first body and around the second body, wherein the sensor is configured to sense the movement in the fluid at a location downstream of a stagnation feature defined by the second body, the stagnation feature configured to cause a stagnation point in the fluid flow when the fluid flows around the second body, andDocket No : A0009202 PCT01 / 1246-061 WOO 1 processing circuitry configured to: receive a signal indicative of the movement in the fluid from the sensor, determine a frequency of the movement in the fluid based on the signal, and determine a flow rate of the fluid flow within the flow path based on the frequency.

[0010] In an example, a method comprises: receiving, by processing circuitry, a signal indicative of movement of a fluid flow from a sensor, wherein the movement is caused when the fluid flows around a first body and around a second body within a flow path defined by a conduit, wherein the fluid flow has a Reynolds number less than or equal to about 9000 within the conduit, and wherein the sensor senses the movement at a location downstream of a stagnation feature of the second body, the stagnation feature configured to cause a stagnation point in the fluid flow when the fluid flows around the second body; determining, by the processing circuitry, a frequency of the movement; and determining, by the processing circuitry, a flow rate of the fluid flow within the flow path based on the frequency.

[0011] The features disclosed as being part of the first aspect of the disclosure can be in the first aspect or the second aspect of the disclosure, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements.Similarly, any features disclosed as being part of the second aspect of the disclosure can be in the first aspect or the second aspect, either alone or in combination, or follow any arrangement or permutation of any one or more of the described elements.BRIEF DESCRIPTION OF DRAWINGS

[0012] FIG. 1 is a schematic illustration of an example system configured to produce a medical solution.

[0013] FIG. 2 is a schematic illustration of an example system configured to produce a medical solution.

[0014] FIG. 3A is a schematic plan view of an example flow detector including one or more bodies within a flow path.

[0015] FIG. 3B is a schematic end view of the example flow detector of FIG. 3 A.

[0016] FIG. 4 is a schematic illustration a flow detector including a first body and a second body within a flow path.

[0017] FIG. 5 is a schematic illustration of a first example of a body of the flow detector.

[0018] FIG. 6 is a schematic illustration of a second example of a body of the flow detector.

[0019] FIG. 7 is a schematic illustration of a third example of a body of the flow detector.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0020] FIG. 8 is a schematic illustration of the flow detector including a first combination of a first body and a second body.

[0021] FIG. 9 is a schematic illustration of the flow detector including a second combination of a first body and a second body.

[0022] FIG. 10 is a schematic illustration of the flow detector including a third combination of a first body and a second body.

[0023] FIG. 11 is a schematic illustration of a flow detector including a fourth combination of a first body and a second body.

[0024] FIG. 12 is a schematic illustration of a flow detector including a fifth combination of a first body and a second body.

[0025] FIG. 13 is a schematic illustration of a flow detector including a sixth combination of a first body and a second body.

[0026] FIG. 14 is a schematic illustration of an example of Strouhal numbers versus Reynolds numbers caused by a flow detector.

[0027] FIG. 15 is a schematic illustration of an example of Strouhal numbers versus Reynolds numbers caused by a flow detector.

[0028] FIG. 16 illustrates a flow diagram of an example technique for determining a flow rate of the fluid using the flow detector.DETAILED DESCRIPTION

[0029] The disclosure describes devices and systems configured to provide one or more medical solutions for use in a medical procedure, and related methods. In some examples, the medical solution is a peritoneal dialysis fluid or a fluid component of a peritoneal dialysis fluid. While the disclosure refers to a peritoneal dialysis fluid, the devices, systems, and methods described herein can be used to produce other medical solutions.

[0030] The system may be configured transport a fluid (e.g., purified water) within the system to, for example, produce a medical solution, and / or for other reasons. For example, the system may be configured to produce a medical solution which includes the fluid and one or more concentrates (e.g., one or more solid or liquid concentrates). In examples, the system is configured to transport the fluid to a container holding a concentrate in order to produce the medical solution within the container (e.g., within a container volume defined by the container). Hence, the systems described herein may allow a patient or caregiver to receive supplies for an at-home dialysis process in the form of solid and / or liquid concentrates within a container, rather than a heavier container containing fully formulated peritoneal dialysisDocket No : A0009202 PCT01 / 1246-061 WOO 1 fluid (or other medical solution). The system may allow the patient or caregiver to produce the dialysate by providing the fluid flow (e.g., purified water) to the container from a local source, avoiding a necessity to store and / or manipulate heavier containers that already include the fluid prior to use. Thus, the system may ease the delivery and / or storage of medical solutions (e.g., dialysate) used in a medical procedure (e.g., a dialysis treatment).

[0031] As an example, peritoneal dialysis treatment may generally require 3-4 exchanges of peritoneal dialysis fluid per day totaling 12-15 L, and can be much more in some patients. Using pre-mixed, sterilized peritoneal dialysis fluid that require storage of these solutions may put significant burden on the patient using the fluids. Each patient may typically use a combination of three different peritoneal dialysis fluid formulations, and generally requires all three on-hand in case they are needed. Because supplies are typically delivered monthly, some peritoneal dialysis systems may require storage for upwards of 900-1,000 L of sterile fluid. Further, the patient or caregiver must move and manipulate large and cumbersome dialysate containers multiple times each day. In addition, because the pre-mixed fluids can freeze in cold weather, special accommodations may be required to receive and store the premixed fluids to protect them from freezing in cold climates. This places additional burden on patients that live in cold climates.

[0032] The production of a medical solution may require that a specified amount of a fluid be present relative to a concentrate in order to control one or more parameters of the medical solution (e.g., one or more parameters dependent on the amount of fluid present). For example, production of a medical solution may require a specified amount of a fluid relative to the concentrate to cause the produced medical solution to have a pH within a particular range, to have a concentration of the concentrate within a specified range, and / or to have some other parameter dependent on the amount of the fluid within the produced medical solution to be within a range. Hence, a medical system configured to produce a medical solution (e.g., for an at-home dialysis process) may generally determine and / or monitor an amount of fluid transported (e.g., to a container), such that the prepared medical solution meets applicable specifications. Alternately or in addition, the medical system may determine and / or monitor amounts of fluid transported when a sensor provides an indication of the parameter (e.g., a pH, a concentration, and / or other parameter), and transport of additional fluid is needed to bring the parameter to within a prescribed range for the medical solution.

[0033] In some medical systems configured to transport a fluid, the medical system may be configured to transport the fluid at relatively lower flow rates, such as flow rates less than about 1000 millimeters per min (ml / min), flow rates less than about 500 ml / min, or someDocket No : A0009202 PCT01 / 1246-061 WOO 1 other relatively low flow rate. For example, the flow rate may be constrained by aspects of the medical system such as, for example, diameters of conduits within the medical system, a desired physical footprint and / or weight of the medical system, capacities of a pump within the medical system, and / or other aspects which tend to dictate transport of the fluid at relatively lower flow rates. However, the medical system may transport the fluid at the relatively lower flow rates in some instances and transport the fluid at a higher flow rate in other instances. In some cases, a flow rate accuracy attainable by the medical system at a higher flow rate may be insufficient, or even unobtainable, for flow rates at the lower flow rates. Thus, the accuracy with which the medical system determines an amount of fluid transported may vary depending on a flow rate at which the fluid is transported. This may cause difficulty in accurately determining and / or monitoring an amount of fluid transported (e.g., to a container), and may reduce a confidence that the prepared medical solution meets applicable specifications.

[0034] The system disclosed is configured to effectively determine an amount of fluid transported over a range of flow rates to, for example, produce a medical solution and / or for other reasons. In examples, the system is configured to determine the amount of fluid transported by determining a flow rate of the fluid (e.g., a flow rate of the fluid provided to a container). The system may include a flow detector which substantially maintains at least a given accuracy (e.g., 1%) over a range of flow rates used to produce the medical solution to, for example, ensure that a parameter of the medical solution is within a prescribed range.

[0035] In examples, the system is configured to determine the amount of fluid (“fluid amount”) provided based on a period of time (“time period”) over which a flow rate occurs. For example, the system may be configured to detect and / or monitor the flow rate within and / or over the time period and substantially integrate the flow rate over a time duration of the time period to determine the fluid amount. The system may determine and / or monitor the fluid amount transported (e.g., to a container) in order to cause a parameter of a medical solution to be within a range prescribed for the medical solution. As used herein, the flow rate of the fluid may be a mass flow rate, a volume flow rate, or some other measure indicative of a mass flow rate and / or a volume flow rate. The fluid amount may be a mass of the fluid, a volume of the fluid, and / or some other measure indicative of a mass and / or volume of the fluid.

[0036] The system includes a flow detector comprising one or more bodies (e.g., bluff bodies) configured to be positioned within a flow path of a fluid. In examples, the flow detector includes a first body and a second body, displaced from the first body, in aDocket No : A0009202 PCT01 / 1246-061 WOO 1 downstream direction of the fluid flow. The system may include a conduit defining a flow path for the fluid. The system may be configured such that the one or more bodies are positioned within the flow path. In examples, the flow detector is configured such that a portion of the fluid encounters the first body prior to encountering the second body as the portion of the fluid flow flows in a downstream direction through the flow path.

[0037] The system includes a sensor configured to sense movement of the fluid caused as the fluid flows around the one or more bodies. For example, in some examples, the sensor may be configured to detect (e.g., downstream of the one or more bodies) a pressure fluctuation indicative of the movement of the fluid flow, a velocity fluctuation indicative of the movement of the fluid flow, and / or another fluctuation of a fluid parameter of the fluid flow caused as the fluid flows around the one or more bodies. In some examples, the one or more bodies are configured to cause vortex shedding of the fluid as the fluid flows around the one or more bodies. The movement of the fluid sensed by the sensor may be indicative of the vortex shedding.

[0038] The system includes processing circuitry configured to receive a signal indicative of the movement of the fluid from the sensor. In examples, the processing circuitry is configured to determine a frequency using the signal. The processing circuitry may be configured to determine a flow rate of the fluid through the flow path defined by the conduit using the frequency. In examples, the processing circuitry is configured to determine the flow rate over a time period and determine a fluid amount which has passed through the flow path using the flow rate and / or the time period. The processing circuitry may be configured to use the determined fluid amount to, for example, determine and / or monitor a fluid amount of a fluid transported to a container during production of a medical solution by the system.

[0039] The one or more bodies (e.g., the first body and / or the second body) define at least one stagnation feature configured to cause a first portion of a fluid flow to divert (e.g., tangentially divert) away from a second portion of the fluid flow when the fluid flow encounters the stagnation feature. The stagnation feature may be configured to cause a stagnation point when the fluid flow encounters the stagnation feature. In examples, the stagnation point refers to a point in a velocity field indicative of the fluid flow where a local velocity is zero and / or where the local velocity may be analytically represented to be zero. In examples, the local velocity is a velocity of the velocity field along a flow axis and in a direction toward the stagnation feature. The stagnation point may be a single point in some examples, may be a point comprising a stagnation line in some examples, and / or may be a point comprising a stagnation surface (e.g., a stagnation plane) in some examples.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0040] In examples, a stagnation feature comprises some portion of a comer defined by the one or more bodies. For example, the stagnation feature may comprise a portion of a comer defined when a first surface of the one or more bodies meets a second surface of the one or more bodies. The first surface may be a substantially planar surface or a surface defining a curvature. The second surface may be a substantially planar surface or a surface defining a curvature. In some examples, the stagnation feature comprises some portion of a surface defined by the one of more bodies, such as a portion of a substantially planar surface (e.g., a substantially planar surface substantially facing a direction of the fluid flow) or a portion of a substantially curved surface (e.g., a substantially curved surface substantially facing the direction of the fluid flow). The one or more bodies may define the stagnation feature in any manner sufficient to cause a stagnation point when the fluid flow encounters the stagnation feature.

[0041] In examples, the one or more bodies include the first body defining a first stagnation feature and the second body defining a second stagnation feature. The first stagnation feature may be configured to cause a first stagnation point when the fluid flow encounters the first stagnation feature. The second stagnation feature may be configured to cause a second stagnation point when the fluid flow encounters the second stagnation feature. The sensor may be configured to sense the movement of the fluid downstream of the second stagnation feature when the fluid flows around the first body and the second body. In examples, the sensor is configured to sense the movement of the fluid downstream of the second body when the fluid flows around the first body and the second body.

[0042] The system may include the conduit defining the flow path. The system may include a pump configured to cause the fluid to move through the flow path of the conduit. The system may be configured such that the pump causes the fluid to move through the flow path at a relatively low flow rate, such as a flow rate less than about 1000 ml / min in some examples, and less than about 500 ml / min in some examples. The system (e.g., the first body, the second body, and / or the conduit) may be configured such that the movement of the fluid sensed by the sensor as the fluid flow flows around the one or more bodies is indicative of the relatively low flow rate to within a certain accuracy. For example, the system may be configured such that, at the relatively low flow rate, the frequency determined by the processing circuitry and based on the movement provide a flow rate measure having an accuracy of within 5% of an actual flow rate in some examples, and within 1% of the actual flow rate in some examples. Hence, when a fluid is transported at the relatively low flow rate, the system may increase an accuracy in the determination of a fluid amount transported in theDocket No : A0009202 PCT01 / 1246-061 WOO 1 production of a medical solution, as compared to medical systems which rely on flow rate and / or fluid volume determinations using other types of sensors, such as weight-based sensors, Corolis flow meters, obstruction type flow meters, inferential type flow meters, and / or others.

[0043] In examples, the system (e.g., the pump) is configured to cause the fluid moving through the conduit to have a flow rate such that a Reynolds number (“Re”) of the fluid flow within the conduit is less than about 9000 in some examples, less than about 5000 in some examples, and less than about 2000 in some examples. In examples, the conduit is configured such that, when the flow rate within the flow path of the conduit is less than about 1000 ml / min, and in some examples less than about 500 ml / min, a Reynolds number of the fluid within the flow path is less than about 9000 in some examples, less than about 5000 in some examples, and less than about 2000 in some examples. In examples, the Reynolds number is based on a density of the fluid within the flow path, a velocity of the fluid within the flow path, a viscosity (e.g., a dynamic viscosity) of the fluid within the flow path, and a characteristic length of a body within the conduit (e.g., a cross-sectional dimension, such as a diameter or other length defined by the body). In examples, the Reynolds number is indicative of a ratio of a product of the density, the velocity, and the characteristic length to the viscosity. For example, the Reynolds number may be defined by a product of a density of the fluid, a velocity of the fluid within the conduit, and a characteristic length of the conduit, with the product divided by a viscosity of the fluid. In examples, the fluid is a substantially incompressible liquid, such as liquid water and / or a liquid comprising liquid water.

[0044] In examples, the system (e.g., the pump) is configured to cause the fluid moving through the conduit to have a flow rate such that a Strouhal number (“St”) of the fluid flow within the conduit is somewhat constant and / or has a somewhat linear relationship with the Reynolds number over a range of Reynolds numbers within the conduit . In examples, the conduit, a first body, and / or a second body is configured such that, when the flow rate within the flow path of the conduit is less than about 1000 ml / min, and in some examples less than about 500 ml / min, the resulting Strouhal number of the fluid within the flow path provides a Coefficient of Determination (R2) with the Reynolds number of at least 0.9 in some examples, and at least 0.95 in some examples. The Strouhal number may be based on a velocity of the fluid within the flow path (e.g., the same velocity used to determine a Reynolds number within the conduit), a characteristic length, and a frequency of the movement of the fluid as the fluid flows around the one or more bodies (e.g., a frequency as determined by the processing circuitry). In examples, the Strouhal number is indicative of aDocket No : A0009202 PCT01 / 1246-061 WOO 1 ratio of a product of the frequency and the characteristic length to the velocity. In some examples, the Strouhal number is defined by a product of a frequency and the characteristic length, with the product divided by the velocity.

[0045] The system (e.g., the pump, the conduit, the first body, and / or the second body) may be configured to cause a plurality of Strouhal numbers of the fluid flow within the conduit which are relatively constant and / or linear over a range of Reynolds numbers within the conduit (e.g., such that the plurality of Strouhal numbers provides a Coefficient of Determination (R2) with the Reynolds number of at least 0.9 in some examples, and at least 0.95 in some examples). In examples, the relatively constant Strouhal number may have an proximate value (e.g., estimated as a result of bench testing of the system). Hence, the system may be configured to detect a parameter (e.g., a frequency) indicative of the Strouhal number and determine a flow rate by determining a velocity of the fluid flow which would cause the proximate value of the Strouhal number.

[0046] Configuring the system such that the plurality of Strouhal numbers provide a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples, may assist and / or improve the accuracy of the flow detector at lower flow rates through the conduit. In examples, the system is configured such that, when a range of Reynolds numbers within the conduit is less than about 9000, the plurality of Strouhal numbers provide a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples.

[0047] For example, the plurality of Strouhal numbers may include a first Strouhal number which results when the fluid flow has a first Reynolds number, a second Strouhal number which results when the fluid flow has a second Reynolds number, a third Strouhal number which results when the fluid flow has a third Reynolds number, and so on to an Nth Strouhal number which results when the fluid flow has an Nth Reynolds number. The system may be configured such that a substantially linear function may define (e.g., predict) the first Strouhal number based on the first Reynolds number, define the second Strouhal number based on the second Reynolds number, define the third Strouhal number based on the third Reynolds number, and define the Nth Strouhal number based on the Nth Reynolds number. In examples, the substantially linear function is a continuous function over range of Reynolds numbers which includes at least the first Reynolds number, the second Reynolds number, the third Reynolds number, and the Nth Reynolds number. In examples, the first Strouhal number and the first Reynolds number, the second Strouhal number and the second Reynolds number, the third Strouhal number and the third Reynolds number, and the Nth Strouhal and the NthDocket No : A0009202 PCT01 / 1246-061 WOO 1Reynolds number define a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples.

[0048] In examples, the system includes one or more containers, with at least one container defining a volume (“container volume”) configured to hold a material. The container may be fluidically coupled to the flow path defined by the conduit. The system may be configured such that an introduction of the fluid flow (e.g., water and / or a liquid concentrate) into the container volume via the conduit causes a medical solution comprising the material to be produced within the container volume. This may allow substantially in-situ production of the medical solution in a manner minimizing and / or avoiding a need for the storage and movement of relatively large and heavier containers of the medical solution. In examples, the medical solution is a dialysis fluid (e.g., a peritoneal dialysis fluid) for use in a dialysis procedure. In some examples, the medical solution comprises (e.g., is a component of) a dialysis fluid. The system (e.g., the processing circuitry) may be configured to determine a fluid amount transported to the container volume during the production of the medical solution such that a parameter of the medical solution dependent on the fluid amount (e.g., a pH, a concentration) is within a specified range. In examples, the processing circuitry is configured to control the pump (e.g., to start, stop, and / or allow to run) based on the fluid amount transported to the container volume.

[0049] The system disclosed is configured to prepare a medical solution (e.g., peritoneal dialysis fluid) with reduced storage and handling requirements. The system may include one or more containers holding a material (e.g., a solid concentrate and / or liquid concentrate) which comprise the medical solution. In some examples, such as when the medical solution comprises a first constituent (e.g., a first liquid concentrate) and a second constituent (e.g., a second liquid concentrate), the medical system may include a first container for preparation of the first constituent and a second container for preparation of the second constituent. The system may include a first conduit configured to provide fluid to the first container a second conduit configured to provide fluid to the second container. The system may include one or more flow detectors configured to determine a flow rate of the fluid flowing through the first conduit and determine a flow rate of the fluid flowing through the first conduit. The system may be configured to produce the first constituent in the first container when fluid is provided to the first container and produce the second constituent in the second container when fluid is provided to the second container. This may provide advantage when it is desirable to subject, for example, the first constituent to one or more preparation steps which might be undesired for the second constituent. In examples, a mixing device is secured to at least one of theDocket No : A0009202 PCT01 / 1246-061 WOO 1 containers to promote mixing of the material and the fluid when a fluid flow is provided to the container. In some examples, the mixing device is configured to draw the material into the fluid flow when the fluid flow is provided to the container.

[0050] For example, the first container may include a first solid concentrate configured to mix with fluid provided via the first conduit to produce the first constituent, such as a first liquid concentrate containing dextrose and / or lactate. The second container may include a second solid concentrate configured to mix with fluid provided via the second conduit to produce the second constituent, such as a second liquid concentrate containing calcium, sodium, magnesium, and / or chloride (e.g., as ions). The system may be configured to subject the first constituent to a first process (e.g., a first amount of dilution and / or reconstitution) which might be undesired for the second constituent, and / or subject the second constituent to a second process (e.g., a second amount of dilution and / or reconstitution) which might be undesired for the first constituent. Hence, the system may be configured to maintain to separation between the first constituent and the second constituent until the first process and / or the second process has been performed.

[0051] The system may be configured to mix the first constituent and the second constituent (e.g., as liquids) in a third container subsequent to performing the first process and / or the second process to produce the medical solution (e.g., a dialysate). For example, the system may be configured to provide the first constituent from the first container to the third container. The system may be configured to provide the second constituent from the second container to the third container. In examples, the system includes one or more pumps and / or one or more valves configured to define a flow path for the first constituent from the first container to the third container and / or define a flow path for the second constituent from the second container to the third container. The control circuitry may be configured to control the one or more pumps and / or valves to cause the mixing of the first constituent and the second constituent in the third container. In examples, the system is configured to provide additional fluid (e.g., purified water) to the third container, such that the resulting medical solution within the third container is a mixture of the first constituent (e.g., the first liquid concentrate), the second constituent (e.g., the second liquid concentrate), and the additional fluid.

[0052] The system may include any number of containers and any number of flow detectors. In examples, the system is configured to receive the fluid (e.g., water) from a water source available in a patient’s home, such that the patient or a caregiver may fluidly couple the system to the water source and make use of the system to produce a medical solutionDocket No : A0009202 PCT01 / 1246-061 WOO 1(e.g., a peritoneal dialysis fluid or a medical solution intended to comprise a peritoneal dialysis fluid). Hence, the system may allow a patient or caregiver to cause the production of a medical solution, such that a container holding only a material comprising the medical solution (e.g., the solid concentrate or the liquid concentrate) may be delivered to the patient or caregiver. This may reduce handling, storage, and delivery burdens on the patient or caregiver compared to systems which require delivery of fully mixed medical solutions and / or peritoneal dialysis solutions. The system may thus ease the delivery and / or storage of medical solutions (e.g., dialysate) used in a medical procedure (e.g., a dialysis treatment).

[0053] FIG. 1 schematically illustrates an example system 100 configured to produce a medical solution (e.g., a peritoneal dialysis fluid and / or a medical solution comprising a peritoneal dialysis fluid). System 100 includes one or more containers, such as a container 104. Container 104 defines a container volume 107 configured to hold a fluid. In examples, system 100 is configured to provide the fluid (e.g., water) to container 104 from a fluid source 102. In examples, system 100 includes a fluid line 101 configured to provide the fluid from fluid source 102 to container 104 (e.g., container volume 107). System 100 may include one or more pumps such as a pump 108 configured to pump the fluid. Pump 108 is configured to cause the fluid to flow (e.g., via fluid line 101) from fluid source 102 to container 104 and / or other portions of system 100.

[0054] In examples, system 100 includes one or more purification modules 103 (e.g., water purification modules) configured to purify and / or treat the fluid provided to container 104. System 100 may be configured to transport fluid from a fluid source 102 (e.g., via fluid line 101) and purification module 103 using pump 108. In examples, fluid source 102 is configured to provide potable or non-potable water. For example, fluid source 102 may be a tap water source, such as a home tap or faucet. In examples, fluid source 102 is configured to provide water meeting World Health Organization (WHO), United States Environmental Protection Agency (EP A), and / or European Union (EU) standards for drinking water. Purification module 103 may be configured to remove chemical contaminants from the fluid to, for example, convert the water from fluid source 102 into water meeting applicable pharmacopoeia requirements for peritoneal dialysis fluid.

[0055] Purification module 103 has any suitable configuration. In some examples, purification module 103 is configured to remove and / or replace ionic species from the fluid. In some examples, purification module 103 includes one or more of a sorbent, an exchange material (e.g., an anion exchange material and / or a cation exchange material), and / or other materials configured to remove and / or replace ionic species in a fluid. In some examples,Docket No : A0009202 PCT01 / 1246-061 WOO 1 purification module 103 includes one or more activated carbon layers or blocks. In some examples, purification module 103 includes a softener configured to soften the fluid (e.g., to remove one or more minerals from the fluid).

[0056] The exchange material (e.g., an anionic exchange material) may be configured to remove anionic species from the fluid, such as nitrate, phosphate, and / or fluoride molecules. In examples, the exchange material is configured to replace the anionic species with acetate or hydroxide ions. The exchange material may be any material capable of removing anionic species from the fluid. In some examples, the exchange material (e.g., a cation exchange material, such as a sorbent) is configured to remove cationic species from the fluid, such as potassium, calcium, magnesium, iron, or other cations. The exchange material may be configured to replace the cationic species with hydrogen and / or sodium. The exchange material may be any material capable of removing cations from the fluid.

[0057] Purification module 103 may include both an anion exchange material and a cation exchange material. In examples, purification module 103 includes at least one ion exchange layer which contains a mixed bed having both a cation exchange material and an anion exchange material. The mixed bed may be configured to generate hydrogen ions and hydroxyl ions as byproducts that form water (e.g., as the mixed bed removes and / or replaces anionic species and / or cationic species from the fluid).

[0058] In examples, purification module 103 includes a carbon material (e.g., an activated carbon material). The carbon material may be configured to adsorb or absorb nonionic molecules, organic molecules, chlorine, chloramine, and other ions from the fluid. In examples, the carbon material may be configured to absorb or absorb endotoxins and / or bacterial contaminants. The carbon material may be present in the form of a carbon block, or as a free-flowing, granular or powder layer. In some examples, purification module 103 includes an oxide (e.g., a metal oxide such as aluminum oxide) to, for example, remove fluoride and heavy metals from the fluid.

[0059] Purification module 103 may include a sorbent and / or resin containing the anion exchange material, the cation exchange material, the carbon material, and / or the metal oxide. In some examples, purification module 103 may include a cartridge holding the sorbent and / or resin. The cartridge can be sized depending on the needs of the user, ranging from a disposable unit that is replaced daily to a larger sized cartridge allowing for production of more medical fluids before the cartridge must be replaced. In some examples, purification module 103 is configured to hold the sorbent and / or resin in another type of container or conduit. In some examples, purification module 103 may include a reverse osmosis module,Docket No : A0009202 PCT01 / 1246-061 WOO 1 electrodeionization module, one or more nanofilters, or any other system capable of removing chemical contaminants from the fluid (e.g., water). Purification module 103 may include a microbial filter (e.g., for removal of endotoxins or bacterial contaminants) and / or a particulate filter (e.g., for removal of particulate matter). In examples, purification module103 is configured to receive the fluid from fluid source 102 and provide a substantially sterile fluid that meets pharmacopoeia requirements related to peritoneal dialysis and / or another medical procedure.

[0060] In some examples, system 100 includes a heater 109 configured to heat the fluid. In examples, heater 109 is configured to heat the fluid subsequent to the fluid passing through purification module 103. The fluid may be optionally heated using heater 109 and pumped (e.g., using pump 108 or another pump) to container 104.

[0061] Container 104 may include components for use in carrying out peritoneal dialysis. For example, container 104 may initially contain solid material and / or a concentrated liquid solution. Fluid (e.g., purified water) may be pumped into container 104 to dissolve the solid material and / or dilute the concentrated liquid solution. As an example, container 104 may contain sodium chloride, calcium chloride, magnesium chloride, sodium lactate, sodium bicarbonate, and / or a polar and / or an osmotic agent. In certain examples, the osmotic agent can be dextrose or glucose. In some examples, the osmotic agent can be icodextrin and / or another material configured for use as an osmotic agent in peritoneal dialysis therapy. In any example, the components used to produce a medical solution (e.g., a peritoneal dialysis fluid) may be stored in separated containers and then mixed together in container 104.

[0062] In examples, system 100 includes a pump 105 configured to cause and / or control a movement of the fluid into and / or out of container volume 107 of container 104.Alternatively, or additionally, system 100 may include one or more valves such as a valve 113 configured to control the movement of fluid through system 100. In examples, container104 is configured to receive the fluid via fluid line 119 fluidically coupled to fluid line 101.

[0063] The system includes a flow detector 118 configured to determine a flow rate of a fluid flow within a flow path defined by fluid line 119. Flow detector 118 comprises one or more bodies positioned within the flow path defined by fluid line 119. In examples, flow detector 118 includes a first body (e.g., first body 166 (FIG. 4)) and a second body (e.g., second body 168 (FIG. 4)) displaced from the first body in a downstream direction of the fluid flow. The one or more bodies (e.g., the first body and / or the second body) define at least one stagnation feature configured to cause movement of the fluid (e.g., pressure and / or velocity fluctuations) as the fluid flows around the one or more bodies. Flow detector 118 isDocket No : A0009202 PCT01 / 1246-061 WOO 1 configured to detect the movement of the fluid using a sensor (e.g., sensor 162 (FIG. 4)) and provide a signal indicative of the movement of the fluid to processing circuitry 120. In examples, flow detector 118 is configured to provide the signal and / or processing circuitry 120 is configured to receive the signal using a communication link 117.

[0064] Processing circuitry 120 may be configured to determine a flow rate of the fluid flow within fluid line 119 by determining a frequency using the signal and determining the flow rate using the frequency. In examples, processing circuitry 120 is configured to determine the flow rate of the fluid flow within fluid line 119 over a time period and determine a fluid amount which has passed through fluid line 119 using the flow rate and / or the time period. Processing circuitry 120 may be configured to use the fluid amount which has passed through fluid line 119 to, for example, determine and / or monitor an amount of fluid transported to container volume 107 (e.g., during production of a medical solution using container 104) by the system

[0065] In examples, processing circuitry 120 is configured to control the one or more pumps (e.g., pump 105, 108) and the one or more valves (e.g., valve 113) of system 100 to produce the medical solution (e.g., a peritoneal dialysis fluid). For example, processing circuitry 120 may be configured to cause pump 105, 108 to transport fluid (e.g., water) into container volume 107 of container 104 via fluid line 119 to produce the medical solution. Processing circuitry 120 may track and / or monitor the amount of fluid transported to container volume 107 by determining a flow rate of the fluid flow within fluid line 119 during a time period (e.g., based on signals from flow detector 118). In examples, processing circuitry 120 is configured to cause pump 105, 108 to cease transporting the fluid to container volume 107 when the amount of fluid transported to container volume 107 meets an particular amount desired for a medical solution within container volume 107.

[0066] Processing circuitry 120 may be configured to communicate and / or control pump 105, 108, valve 113, flow detector 118, and / or other components of system 100 using one or more communication links. For example, processing circuitry 120 may be configured to communicate with and / or control pump 105 using communication link 121. Processing circuitry 120 may be configured to communicate with and / or control pump 108 using communication link 123. Processing circuitry 120 may be configured to communicate with and / or control valve 113 using communication link 125. System 100 may include additional communication links configured to communicate with and / or control other components in other examples.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0067] In examples, system 100 is configured to cause a fluid flow provided via fluid line 119 to have a flow rate such that a Reynolds number of the fluid flow flowing through flow detector 118 is less than about 9000 in some examples, less than about 5000 in some examples, and less than about 2000 in some examples. For example, pump 105 may be configured to cause the fluid to flow at one or more flow rates through and / or into fluid line 119, flow detector 118, container volume 107, and / or other components of system 100 (e.g., mixing device 116) such that the fluid flow through flow detector 118 has the Reynolds number less than about 9000 in some examples, less than about 5000 in some examples, and less than about 2000 in some examples. In some examples, system 100 is configured such that the fluid flow through flow detector 118 has the Reynolds number less than about 9000 in some examples, less than about 5000 in some examples, and less than about 2000 in some examples when pump 105, 108 causes the flow rate through flow detector 118 to be less than about 1000 ml / min, and in some examples less than about 500 ml / min.

[0068] In some examples, system 100 includes one or mixing devices such as a mixing device 116. Mixing device 116 may be configured to promote and / or cause a mixing of the fluid provided to container 104 and at least one component of a medical solution (e.g., a solid concentrate and / or a liquid concentrate). In some examples, mixing device 116 is configured to draw the component into the fluid flow such that the fluid flow and the component at least partially mix within and / or downstream of mixing device 116. Mixing device 116 may be configured to discharge a mixture of the fluid flow and the component into container 104 (e.g., container volume 107). In some examples, mixing device 116 may be configured to draw in the component from container volume 107 (e.g., container volume 107 may initially hold the component). In some examples, mixing device 116 may be configured to draw in the component from another container (not shown).

[0069] System 100 may include one or more detectors such as detector 111 configured to sense and / or determine a concentration and / or other parameter of the medical solution within container 104 (e.g., container volume 107). Processing circuitry 120 may be configured to communicate with and / or control detector 111 using communication link 127. Detector 111 may be used to provide assurance that the concentration and / or other parameter of the medical solution is within a predetermined range. For example, detector 111 may be a conductivity sensor configured to determine a concentration of ionic components in the medical solution. Alternatively, or additionally, detector 111 may include a refractive index sensor, polarimetric sensor, or other sensor configured to determine an osmotic agent concentration in the medical fluid.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0070] In examples, system 100 (e.g., processing circuitry 120) is configured to assess when dissolution of a solid material and / or dilution of a liquid concentrate is complete. For example, processing circuitry 120 may be configured to determine when detector 111 provides a reading within an acceptable range and assess that the dissolution and / or dilution may be assessed as completed based on the reading. Processing circuitry 120 may be configured to determine a variability of readings from the detector 111 and assess that dissolution and / or dilution is complete when the reading does not fluctuate greater than a predetermined amount.

[0071] In some examples, system 100 includes a recirculation line 110 configured to recirculate a medical solution within container volume 107. System 100 (e.g., under the control of processing circuitry 120) may be configured to recirculate the medical solution to assist in establishing a homogeneity of the medical solution (e.g., subsequent to production of the medical solution using fluid provided by fluid line 101). In some examples, for example following the addition of a predetermined amount of fluid to container volume 107 to produce a medical solution, system 100 may be configured to recirculate the medical solution using recirculation line 110 to assist in establishing a relatively homogenous concentration of the component within the medical solution.

[0072] In some examples, processing circuitry 120 is configured to assess the concentration of the component to assess a homogeneity of the medical solution. For example, processing circuitry 120 may be configured to compare the concentration of the component to a predetermined tolerance range (e.g., stored in a memory of system 100 or another system). If the concentration is outside of the tolerance range, then processing circuitry 120 may cause system 100 to recirculate the medical solution using recirculation line 110. Subsequent to the recirculation, processing circuitry 120 may be configured to cause system 100 to again determine the concentration of the component and compare concentration to the tolerance range. Processing circuitry 120 may be configured to cause system 100 to recirculate the medical solution using recirculation line 110 until the concentration is within the tolerance range.

[0073] In some examples, system 100 (e.g., under the control of processing circuitry 120) is configured to recirculate the medical solution to assist in establishing a homogeneity of a first component relative to a second component in a medical solution. For example, system 100 may be configured to add fluid (e.g., a predetermined amount of fluid determined using, for example, flow detector 118) from fluid line 101 to container volume 107 to produce a medical solution comprising the first component, the second component, and the fluid.Docket No : A0009202 PCT01 / 1246-061 WOO 1Processing circuitry 120 may be configured to determine when the predetermined amount has been added using flow detector 118. System 100 (e.g., processing circuitry 120) may be configured to determine a first concentration of the first component and a second concentration of the second component in the medical solution (e.g., subsequent to adding the predetermined amount of fluid). For example, processing circuitry 120 may include a first sensor configured to determine the first concentration and a second sensor configured to determine the second concentration. Processing circuitry 120 may be configured to cause system 100 to recirculate the medical solution using recirculation line 110 until the first concentration is within a first tolerance range and the second concentration is within a second tolerance range.

[0074] In some examples, processing circuitry 120 is configured to determine whether the first component and the second component are incorrectly mixed within the medical solution. For example, if, following a predetermined number of recirculations, the first concentration remains outside of the first tolerance range or the second concentration remains outside of the second tolerance range, or if both the first concentration and the second concentration remain outside their respective tolerance ranges, then processing circuitry 120 may determine that the first component and / or the second component are mixed improperly (e.g., in improper respective amounts) in the medical solution. In examples, processing circuitry 120 is configured to issue an alert in response to assessing the improper mixing, and / or prevent use of the medical solution in subsequent operations of system 100 (e.g., using valve 113 and / or pump 105, 108). For example, processing circuitry 120 may cause the disposal of the medical solution stored in container 104.

[0075] Although shown in recirculation line 110, detector 111 and / or additional sensors of system 100 can be placed in fluid line 101 or another portion of system 100.

[0076] The amount (e.g., volume or mass) of fluid pumped into container 104 may depend on the amount of a component initially contained within container 104. In certain examples, container 104 contains one or more components required to produce a peritoneal dialysis fluid. The components can be mixed, dissolved, or reconstituted to produce a peritoneal dialysis fluid. In other examples, the components can be separate concentrates added in specific amounts to container 104. The addition of fluid to container 104 to produce a peritoneal dialysis fluid may minimize and / or eliminate a need for pre-mixed fluids, which may ease existing burdens on patients and caregivers. For example, when a 6 liter (L) dialysate container is used, the total weight of the components (e.g., the constituent parts minus the fluid) may be about 325 grams (g) or less, compared to about 6 kilograms (kg) orDocket No : A0009202 PCT01 / 1246-061 WOO 1 more for the pre-mixed fluid bag. The volume of storage for a flexible 6L container containing only the components can be about 300-500 cubic centimeters, whereas the premixed fluid bag may be about 6000 cubic centimeters. The smaller size and weights may significantly reduce the space and / or efforts required to store supplies for a peritoneal dialysis treatment.

[0077] In some examples, system 100 includes a sterilization module 106. Sterilization module 106 can be any component or set of components capable of substantially sterilizing a medical solution, such as a peritoneal dialysis solution of a liquid component of a peritoneal dialysis solution. System 100 may be configured to pump the medical solution from container 104 (e.g., container volume 107) and through sterilization module 106. In some examples, sterilization module 106 includes one or more ultrafilters. Additionally, or alternatively, sterilization module 106 can include an ultraviolet (UV) light source and / or a microbial filter. Any of the components used in sterilization module 106 may be configured to be replaced as necessary. Alternatively, or additionally, sterilization module 106 can include a flash pasteurization module to sterilize the medical solution. In examples, sterilization module 106 is configured such that a user may adjusting the mode of sterilization based on a mode of use of system 100. For example, a first type of sterilization can be used when the medical solution (e.g., a liquid component of a peritoneal dialysis solution) is produced for later use. A second type of sterilization can be used when the medical solution (e.g., a peritoneal dialysis solution) is produced for immediate use.

[0078] System 100 may be configured to pump the medical solution to a container 114 for storage until ready for use by a patient. In some examples, system 100 can be connected to a cycler (not shown) for immediate or later infusion of a peritoneal dialysis fluid comprising the medical solution into a patient. The peritoneal dialysis fluid can be directly infused into the patient after sterilization by connecting fluid line 101 to a catheter. Alternatively, the fluid can be stored in container 114 and subsequently pumped from container 114 and infused into the patient. Although shown in FIG. 1 as fluidically coupled to fluid line 101 by fluid line 119 and / or pump 105, in certain examples, container 104 can be placed substantially in-line with fluid line 101. For example, in some examples, container 104 may be directed connected to fluid line 101.

[0079] FIG. 2 schematically illustrates an example of another example system 200 configured to produce a medical solution (e.g., a peritoneal dialysis fluid and / or a medical solution comprising a peritoneal dialysis fluid) using container 104, container 114, and a container 122. System 200 is an example of system 100. System 200 includes valve 113Docket No : A0009202 PCT01 / 1246-061 WOO 1 configured to control a flow of fluid through a fluid line 132 fluidically coupling fluid line 101 and container volume 107. System 200 further includes a valve 124 configured to control a flow of fluid through a fluid line 134 fluidically coupling fluid line 101 and a container volume 123 defined by container 122, and a valve 126 configured to control a flow of fluid through a fluid line 136 fluidically coupling fluid line 101 and a container volume 115 defined by container 114. Fluid lines 132, 134, 136 may be an example of fluid line 119 (FIG. 1).

[0080] System 200 includes detector 111 configured to determine a concentration and / or other parameter of a first solution within container 104. In examples, system 200 includes a detector 128 configured to determine a concentration and / or other parameter of a second solution within container 122. System 200 may include a detector 130 configured to determine a concentration and / or other parameter of a medical solution (e.g., a peritoneal dialysis fluid) within container 122. Although detector 111 is shown as configured to determine a concentration and / or other parameter within container 104 and / or container volume 107 in FIG. 2, detector 128 is shown as configured to determine a concentration and / or other parameter within container 122 and / or container volume 123 in FIG. 2, and detector 130 is shown as configured to determine a concentration and / or other parameter within container 114 and / or container volume 115 in FIG. 2, detector 111, detector 128, detector 130, and / or other sensors of system 200 may be placed in other portions of system 200 in other examples. For example, instead of or in addition to detector 111, detector 128, and / or detector 130, system 200 may include a detector 137 configured to determine a concentration and / or other parameter of a fluid within a discharge line 139 in fluidic communication with container volume 115.

[0081] Container 104 is configured to hold a first component of the medical solution. For example, container 104 may be configured to hold a first concentrate (e.g., a first solid concentrate and / or a first liquid concentrate) comprising a first constituent of the medical solution. System 200 may be configured to produce the first constituent within container volume 107 when a first amount of fluid (e.g., purified water) is provided to container volume 107 (e.g., via fluid line 132 and / or valve 113). System 200 (e.g., processing circuitry 120) may be configured to determine the first amount using flow detector 118. In some examples, mixing device 116 may be configured to mix the first amount and the first concentrate and discharge a mixture comprising the first amount and the first constituent into container volume 107. For example, when the first concentrate is a first solid concentrate, mixing device 116 and / or other portions of system 200 may be configured to mix the firstDocket No : A0009202 PCT01 / 1246-061 WOO 1 amount and the first solid concentrate to produce a first liquid comprising the first amount and the first constituent.

[0082] Container 122 is configured to hold a second component of the medical solution. For example, container 122 may be configured to hold a second concentrate (e.g., a second solid concentrate and / or a second liquid concentrate) comprising a second constituent of the medical solution. System 200 may be configured to produce the second constituent within container volume 123 when a second amount of fluid is provided to container volume 123 (e.g., via fluid line 134 and / or valve 124). System 200 (e.g., processing circuitry 120) may be configured to determine the second amount using a flow detector 141. Flow detector 141 may be configured similarly to flow detector 118. In examples, a mixing device 138 is configured to mix the second amount and the second concentrate and discharge a mixture comprising the second amount and the second constituent into container volume 123. For example, when the second concentrate is a second solid concentrate, mixing device 138 and / or other portions of system 200 may be configured to mix the second amount and the second solid concentrate to produce a second liquid comprising the second amount and the second constituent. In examples, flow detector 141 is configured to provide a signal indicative of a flow rate of the fluid through fluid line 134 to processing circuitry 120 using a communication link 145. Processing circuitry 120 may be configured to determine the second amount using the signal provided via communication link 145.

[0083] In some examples, processing circuitry 120 is configured to control valves 113, 124, 126 and / or pump 105 such that the first portion of fluid enters container 104. In examples, processing circuitry 120 is configured to control valves 113, 124, 126 and / or pump 105 such that the first portion is substantially prevented from entering container 122 and container 114 when the first portion enters container 104. For example, processing circuitry 120 may be configured to establish a configuration of system 200 wherein valve 113 is open, valve 124 is shut, and valve 126 is shut when container 104 receives the first portion. In examples, processing circuitry 120 is configured to control valves 113, 124, 126 and / or pump 105 such that the second portion of fluid enters container 122. In examples, processing circuitry 120 is configured to control valves 113, 124, 126 and / or pump 105 such that the second portion is substantially prevented from entering container 104 and container 114 when the second portion enters container 122. For example, processing circuitry 120 may be configured to establish a configuration of system 200 wherein valve 113 is shut, valve 124 is open, and valve 126 is shut when container 122 receives the second portion.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0084] In some examples, the first constituent includes dextrose and / or lactate and the second constituent includes ions (e.g., calcium ions, sodium ions, magnesium ions, and / or chloride ions). In some examples, the first constituent includes ions (e.g., calcium ions, sodium ions, magnesium ions, and / or chloride ions) and the second constituent includes dextrose and / or lactate.

[0085] System 200 may be configured to mix the first liquid containing the first constituent and the second liquid containing the second constituent in container 114 (e.g., in container volume 115) to produce the medical solution. For example, system 200 may be configured to deliver the first liquid from container 104 to container 114 (e.g., via fluid line 132, fluid line 101, and fluid line 136 in some examples). System 200 may be configured to deliver the second liquid from container 122 to container 114 (e.g., via fluid line 134, fluid line 101, and fluid line 136 in some examples). In examples, system 200 is configured to deliver the first liquid to container 114 either subsequent to or preceding the delivery of the second liquid to container 114. In some examples, for example when container 104 is configured to receive fluid from fluid line 101 (e.g., via fluid line 132) at a location upstream of where container 122 receives fluid from fluid line 101 (e.g., via fluid line 134), system 200 is configured to deliver the first liquid from container 104 subsequent to the delivery of the second liquid from container 122 to, or example, substantially flush any of the second liquid which may be remaining in fluid line 101 and / or fluid line 136 into container 114.

[0086] Processing circuitry 120 may be configured to control valves 113, 124, 126 and / or pump 105 to deliver the first liquid to container 114 (e.g., container volume 115). In examples, processing circuitry 120 is configured to control valves 113, 124, 126 and / or pump 105 such that the first liquid is substantially prevented from entering container 122 when the first liquid enters container 114. For example, processing circuitry 120 may be configured to establish a configuration of system 200 wherein valve 113 is open, valve 124 is shut, and valve 126 is open when container 114 receives the first liquid. In examples, processing circuitry 120 is configured to control valves 113, 124, 126 and / or pump 105 to deliver the second liquid to container 114 (e.g., container volume 115). In examples, processing circuitry 120 is configured to control valves 113, 124, 126 and / or pump 105 such that the second liquid is substantially prevented from entering container 104 when the second liquid enters container 114. For example, processing circuitry 120 may be configured to establish a configuration of system 200 wherein valve 113 is shut, valve 124 is open, and valve 126 is open when container 114 receives the second liquid.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0087] In examples, system 200 is configured to produce a medical solution in container 114 comprising a particular amount of the first liquid and a particular amount of the second liquid. In some examples, the medical solution may comprise a particular amount of the fluid. Processing circuitry 120 may be configured to cause system 200 to deliver the particular amount of the first liquid from container 104 to container 114, deliver the particular amount of the second liquid from container 122 to container 114, and / or deliver the particular amount of fluid from fluid source 102 to container 114. In examples, system 200 (e.g., processing circuitry 120) is configured to determine the particular amount of the first liquid, the particular amount of the second liquid, and / or the particular amount of fluid from fluid source 102, using a flow detector 143. System 200 may be configured to cause a mixing of the first liquid and the second liquid within container volume 115. In examples, system 200 includes a mixing device 140 configured to cause mixing of the first liquid and the second liquid. In examples, flow detector 143 is configured to provide a signal indicative of a flow rate through fluid line 136 to processing circuitry 120 using a communication link 147. Flow detector 143 may be configured similarly to flow detector 118, 141. Processing circuitry 120 may be configured to determine the particular amount of the first liquid and / or the particular amount of the second liquid using the signal provided via communication link 147.

[0088] In examples, instead of or in addition to flow detector 118, 141, 143, system 200 may include a flow detector configured to provide a signal indicative of a flow rate through fluid line 136 to processing circuitry 120. For example, system 200 may include a flow detector 171 (shown in dashed lines), a flow detector 173 (shown in dashed lines), and / or a flow detector 175 (shown in dashed lines) configured to provide a signal indicative of a flow rate through fluid line 136. System 200 (e.g., processing circuitry 120) may be configured to determine an amount of fluid provided to and / or from container 107, container 122, and / or container 114 using flow detector 171 and / or flow detector 173.

[0089] In some examples, processing circuitry 120 is configured to assess a mixing of the first liquid, the second liquid, and / or a fluid within container volume 115 based on a signal received from detector 130, which may be indicative of a composition of a medical solution in volume 115. For example, processing circuitry 120 may be configured to determine when detector 130 provides a reading within an acceptable range and determine that mixing of the first liquid, the second liquid, and / or the fluid is sufficiently complete based on the reading. In some examples, processing circuitry 120 is configured to determine a variability of readings from the detector 130 and assess that the mixing of the first liquid, the second liquid, and / or the fluid is sufficiently complete when the reading does not fluctuate greater than aDocket No : A0009202 PCT01 / 1246-061 WOO 1 predetermined amount. In some examples, processing circuitry 120 may cause system 200 to adjust the mixture in container 114 based on the reading from detector 130, such as by causing further amounts of the first liquid, the second liquid, and / or the fluid to be added to container volume 115 of container 114 based on the reading from detector 130.

[0090] In some examples, container 114 and / or container 122 includes a dedicated recirculation line configured to recirculate a mixture within container volume 115 or container volume 123. The dedicated recirculation line may be configured within respect to container 114 and / or container 122 in the same manner as the configuration of recirculation line 110 with respect to container 104. System 200 (e.g., processing circuitry 120) may be configured to recirculate a medical solution within container volume 115 and / or container volume 123 to assist in establishing a homogeneity of the medical solution. In examples, system 200 (e.g., processing circuitry 120) is configured to recirculate the medical solution using the dedicated recirculation line based on a reading from detector 130 and / or a reading from detector 128. System 200 (e.g., processing circuitry 120) may be configured to recirculate a medical solution using the dedicated recirculation line and based on the reading from detector 130, 128 in a similar manner and / or using similar criteria as the recirculation of a medical solution using recirculation line 110 based on a reading from detector 111.

[0091] Containers 104, 114, 122 can each have any suitable configuration. In some examples, one or more of container 104, 114 or 122 is a reusable sterilized container or bag. The reusable container or bag can be cleaned and sterilized daily, or at set time periods. System 200 and / or container 104, 114, 122 may include one or more connectors (not shown) configured to allow removal of container 104, 114, 122 from system 200. The connectors may be any type of connector configured to allow removal of container 104, 114, 122 from system 200. In certain examples, one or more of the containers 104, 114, 122 may be a rigid container of fixed volume, such as a stainless-steel or rigid plastic container. If a rigid container is used, a vent (not shown) can be added to let air exit container 104, 114, 122 as a fluid enters container 104, 114, 122. The vent may include a sterile filter to avoid contaminations from the external environment.

[0092] System 200 may optionally contain a level sensor and / or a weight sensor (not shown) configured to indicate when the rigid container may be filled. Processing circuitry 120 may be configured to detect when a proper volume of fluid has been added to the rigid container based on a signal from the level sensor (e.g., a signal indicative of the level within a container volume defined by the rigid container). In some examples, container 104, 114, 122 may be a flexible and semi-compliant design that minimizes the volume required for storageDocket No : A0009202 PCT01 / 1246-061 WOO 1 prior to use. In some examples, container 104, 114, 122 may include one or more components to increase a rate of dissolution of a solid material and / or rate of dilution of a liquid material. For example, container 104, 114, 122 may include stir bars or other components to increase the rate of dissolution and / or the rate of dilution (e.g., when container 104, 114, 122 is placed on an external mixing apparatus).

[0093] FIG. 3 A is a schematic plan view of flow detector 118, illustrated in accordance with the X-Y-Z axes shown. Flow detector 141, flow detector 143, and / or other flow detectors of system 100, 200 may be examples of flow detector 118. Flow detector 118 includes a conduit 144 defining a flow path FP for a fluid flow F. Conduit 144 defines a longitudinal axis L extending through flow path FP. In FIG. 3A, conduit 144 is illustrated as a cross-section with a cutting plane taken parallel to longitudinal axis L and / or the X-axis. FIG. 3B is an end view of flow detector 118, illustrated in accordance with the X-Y-Z axes shown, and with conduit 144 illustrated as a cross-section with a cutting plane taken perpendicular to longitudinal axis L and / or parallel to the Z-axis. Conduit 144 may be a portion of fluid line 101, 132, 134, 136.

[0094] Conduit 144 includes a conduit wall 146 defining an inner surface 148 (“conduit inner surface 148”) and an outer surface 150 (“conduit outer surface 150”) opposite conduit inner surface 148. In examples, conduit inner surface 148 defines at least a portion of a boundary of flow path FP. In some examples, conduit inner surface 148 surrounds longitudinal axis L. Conduit 144 (e.g., conduit wall 146”) may include an inlet portion 152 (“conduit inlet portion 152”) and an outlet portion 154 (“conduit outlet portion 154”). In examples, conduit 144 is configured such that fluid flow F flows in a downstream direction D from conduit inlet portion 152 to conduit outlet portion 154 when fluid flow F flows through flow path FP. As used herein, when a first portion of system 100 and / or fluid flow F is downstream of a second portion of system 100 and / or fluid flow F, this may mean the second portion is displaced from the first portion in the downstream direction D. When a first portion of system 100 and / or fluid flow F is upstream of the second portion of system 100 and / or fluid flow F, this may mean the second portion is displaced from the first portion in a direction opposite the downstream direction D.

[0095] Flow detector 118 includes one or more bodies 156 (“bodies 156”) positioned within flow path FP. Flow detector 118 is configured to cause fluid flow F to flow around bodies 156 when fluid flow F flows through flow path FP (e.g., in the downstream direction D). Although represented with a single dashed border in FIG. 3 A and FIG. 3B, bodies 156 may have, include, and / or define any of the characteristics discussed herein for one or moreDocket No : A0009202 PCT01 / 1246-061 WOO 1 bodies positioned within flow path FP. For example, in some examples, bodies 156 may include a first body (e.g., first body 166 (FIG. 4) and a second body (e.g., second body 168 (FIG. 4)).

[0096] Bodies 156 define one or more stagnation features such as stagnation feature 158. Stagnation feature 158 is configured to cause movement of fluid flow F as the fluid flow F flows through flow path FP (e.g., as fluid flow F flows around bodies 156). In examples, the movement is caused by pressure and / or velocity fluctuations within fluid flow F caused by the movement of fluid flow F. Stagnation feature 158 may be configured to cause fluid flow F to divert as fluid flow F encounters stagnation feature 158. For example, stagnation feature 158 may be configured to cause a first portion of fluid flow F to divert (e.g., tangentially divert) away from a second portion of fluid flow F when fluid flow F encounters stagnation feature 158. In examples, stagnation feature 158 is configured such that the movement of fluid flow F causes fluid flow F to form vortices 160.

[0097] Vortices 160 may be a portion of fluid flow F wherein the movement of fluid flow F causes the portion of fluid flow F to generally revolve (e.g., flow around) an axis extending through fluid flow F (e.g., a straight axis or a curved axis). In examples, fluid flow F defines a vorticity indicative or a rotary motion of a point within fluid flow F when fluid flow F forms vortices 160. In examples, the vorticity is indicative of a curl of a velocity field defined by fluid flow F (e.g., a velocity field defined within vortices 160). In examples, the movement of fluid flow F and / or vortices 160 are caused by or result from pressure and / or velocity fluctuations within fluid flow F. Bodies 156 (e.g., stagnation feature 158) may be configured such that fluid flow F forms vortices 160 as a result of fluid flow F encountering stagnation feature 158 and / or bodies 156. In examples, bodies 156 are configured to cause fluid flow F to form vortices 160 downstream of stagnation feature 158 and / or bodies 156.

[0098] Stagnation feature 158 may be configured to cause a stagnation point within a velocity field defined by fluid flow F. In examples, stagnation feature 158 is configured to cause the stagnation point when fluid flow F encounters stagnation feature 158. The stagnation point may be a point in the velocity field where a local velocity of fluid flow F is zero and / or where the local velocity of fluid flow F is analytically represented to be zero. In examples, the local velocity is a velocity of the velocity field (e.g., a velocity profile of the velocity field) along a flow axis and in a direction from conduit inlet portion 152 towards stagnation feature 158 (e.g., in downstream direction D). The stagnation point may be a single point within the velocity field of fluid flow F in some examples, may be a point comprising a stagnation line within the velocity field of fluid flow F in some examples,Docket No : A0009202 PCT01 / 1246-061 WOO 1 and / or may be a point comprising a stagnation surface within the velocity field of fluid flow F (e.g., a stagnation plane) in some examples.

[0099] In some examples, bodies 156 and / or stagnation feature 158 are configured to cause fluid flow F to exhibit a von Karmen effect. Bodies 156 may be configured such that fluid flow F (e.g., vortices 160) produce a substantially repeating pattern of swirling vortices. In examples, bodies 156 and / or stagnation feature 158 are configured to cause fluid flow F to undergo vortex shedding. Bodies 156 and / or stagnation feature 158 may be configured such that fluid flow F forms vortices 160 downstream of stagnation feature 158 and / or a trailing edge 159 of bodies 156. In examples, bodies 156 at least from extend from stagnation feature 158 to trailing edge 159. In some examples, trailing edge 159 is a portion of bodies 156 wherein all other portions of bodies 156 are upstream of trailing edge 159. In some examples, bodies 156 and / or stagnation feature 158 are configured such that fluid flow F generates vortices 160 in the vicinity of (e.g., slightly upstream of, slightly downstream of, or slightly even with) trailing edge 159 as portions of fluid flow F flow over and periodically detach from bodies 156.

[0100] In some examples, as will be discussed, bodies 156 include a first body and a second body downstream of the first body. Bodies 156 may be configured such that fluid flow F produces vortices 160 as fluid flow F flows over the first body and the second body. In some examples, the second body defines trailing edge 159. In examples, bodies 156 may be configured such that the first body causes fluid flow F to form first vortices (e.g., first vortices 178 (FIG. 4)) and the second body causes fluid flow F to form second vortices (e.g., second vortices 180 (FIG. 4)) when fluid flow F flows over the first body and the second body.

[0101] Flow detector 118 is configured to detect the movement of fluid flow F (e.g., within vortices 160) to determine a flow rate of fluid flow F within flow path FP. In examples, flow detector 118 (e.g., bodies 156, conduit 144) is configured such the movement of fluid flow F defines a frequency (e.g., a vortex shedding frequency) indicative of a flow rate of fluid flow F through flow path FP. In examples, flow detector 118 is configured such that vortices 160 define the frequency indicative of the flow rate. In some examples, flow detector 118 is configured such that the frequency has a positive correlation with the flow rate of fluid flow F through flow path FP. For example, flow detector 118 may be configured such that movement of fluid flow F defines a lower frequency when fluid flow F has a lower flow rate through flow path FP and defines a higher frequency greater than the lower frequency when fluid flow F has a higher flow rate through flow path FP greater than theDocket No : A0009202 PCT01 / 1246-061 WOO 1 lower flow rate. Hence, flow detector 118 may be configured to detect the movement of fluid flow F (e.g., within vortices 160) and determine a flow rate of fluid flow FP through conduit flow path FP based on a frequency defined by the movement of fluid flow F.

[0102] Flow detector 118 may include a sensor 162 configured to detect the movement. In examples, sensor 162 is configured to detect the pressure and / or velocity fluctuations of fluid flow F (e.g., within vortices 160). In examples, sensor 162 is configured to detect the pressure and / or velocity fluctuations of fluid flow F at a location within flow path FP downstream of stagnation feature 158 and / or trailing edge 159. Sensor 162 is configured to produce a signal indicative of the movement of fluid flow F (e.g., indicative of the pressure and / or velocity fluctuations of fluid flow F).

[0103] In examples, sensor 162 is a substantially remote sensor, such that a physical footprint of sensor 162 within flow path FP is limited or even absent. For example, sensor 162 may be an acoustic sensor (e.g., an ultrasound sensor) configured to emit a sound wave into fluid flow F (e.g., into vortices 160). In examples, sensor 162 includes an emitter 161 configured to emit the sound wave into fluid flow F. Sensor 162 may include a receiver 163 configured to receive the sound wave emitted by sensor 162 (e.g., emitted by emitter 161). In examples, sensor 162 is configured such that a phase shift of the sound wave is indicative of the movement of fluid flow F (e.g., indicative of velocity fluctuations and / or pressure fluctuations of fluid flow F). Sensor 162 (e.g., emitter 161 and / or receiver 163) may be configured to emit a plurality of sound waves into vortices 160 over some time interval and produce a signal over the time interval, such that the signal is indicative of the movement of fluid flow F over the time interval.

[0104] In some examples, sensor 162 is configured to detect movement of fluid flow F using mechanical vibrations caused by the movement of fluid flow F (e.g., mechanical vibrations caused by pressure fluctuations of fluid flow F). For example, sensor 162 may include a piezoelectric or capacitance based sensor configured to detect mechanical vibrations of a body within fluid flow F (e.g., bodies 156 or another body). Flow detector 118 may be configured such that the body experiences the mechanical vibrations when (e.g., as a result of) fluid flow F forms vortices 160. The mechanical vibrations of the body may be indicative of the movement of fluid flow F. In examples, sensor 162 is configured to generate an electrical signal (e.g., a voltage signal) indicative of the mechanical vibrations of the body. Sensor 162 may be configured to detect the mechanical vibrations over the time interval and produce the signal over the time interval based on the mechanical vibrations, such that the signal is indicative of the movement of fluid flow F over the time interval.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0105] In some examples, sensor 162 may include a thermal-based sensor configured to detect movement of fluid flow F based on a transfer of heat from or to fluid flow F. Sensor 162 may be configured to detect the heat transfer over the time interval and produce the signal over the time interval based on the heat transfer, such that the signal is indicative of the movement of fluid flow F over the time interval. Sensor 162 may include any type of sensor configured to detect the movement of fluid flow F (e.g., within vortices 160) and provide a signal (e.g., over the time interval) indicative of the movement of fluid flow F. Further, sensor 162 may be located at other positions in addition to that shown in FIG. 4. Sensor 162 may be positioned in any location allowing for the detection of the movement of fluid flow F (e.g., within vortices 160) and the provision of a signal indicative of the movement of fluid flow F.

[0106] In some examples, sensor 162 may include an optical-based sensor configured to detect movement of fluid flow F based on an emission of light through fluid flow F. For example, emitter 161 may be configured to emit a light into fluid flow F (e.g., into vortices 160). Receiver 163 may be configured to receive the light emitted by emitter 161. In examples, sensor 162 is configured such that an amount of light reaching receiver 163 relative to an amount of light emitted by emitter 163 is indicative of the movement of fluid flow F (e.g., indicative of velocity fluctuations and / or pressure fluctuations of fluid flow F). Sensor 162 (e.g., emitter 161 and / or receiver 163) may be configured to emit a plurality of light waves into vortices 160 over some time interval and produce a signal over the time interval, such that the signal is indicative of the movement of fluid flow F over the time interval.

[0107] Sensor 162 is configured to provide a signal indicative of the movement of fluid flow F to processing circuitry 120. Flow detector 118 (e.g., processing circuitry 120) is configured to determine a volume or mass flow rate of fluid flow F through flow path FP using the signal. In examples, processing circuitry 120 is configured to determine a frequency of the signal. The frequency may be indicative of the movement of fluid flow F. In examples, the frequency is indicative of a number of repeating events of the signal (e.g., an amplitude) per unit of time (e.g., a temporal frequency). In examples, the repeating event is indicative of a repeating aspect of fluid flow F caused by the movement of fluid flow F (e.g., indicative of a particular pressure of fluid flow F during pressure fluctuations of fluid flow F, indicative of a particular velocity of fluid flow F during velocity fluctuations of fluid flow F, and / or indicative of another repeating aspect of fluid flow F caused by the movement of fluid flow F). Processing circuitry 120 may be configured to determine the frequency in any manner.Docket No : A0009202 PCT01 / 1246-061 WOO 1For example, processing circuitry 120 may be configured to determine the frequency by using one or more types of a Fourier transform, a Lomb periodogram, a wavelet, a cosine / sine transform, aZ transform, aHankel transform, and / or other methodologies.

[0108] Processing circuitry 120 may be configured to determine a fluid amount of fluid flow F which passes through flow path FP using the flow rate. For example, processing circuitry 120 may be configured to determine and / or monitor the flow rate within and / or over a time period using the signal provided by sensor 162. Processing circuitry 120 may substantially integrate the flow rate over a time duration of the time period to determine the fluid amount. Hence, when conduit 144 is configured to provide fluid flow F to a container 104, 114, 122 of system 200, processing circuitry 120 may substantially determine the fluid amount provided to container 104, 114, 122 (FIG. 2) using the signal provided by sensor 162. Processing circuitry 120 may determine and / or monitor the fluid amount transported to container 104, 114, 122 to cause a parameter of a medical solution produced within container 104, 114, 122 to be within a range prescribed for the medical solution.

[0109] In examples, pump 105 is configured to cause fluid flow F to flow through flow path FP. Processing circuitry 120 may be configured to control pump 105 (e.g., via communication link 121). For example, processing circuitry 120 may be configured to communicate with pump 105 to cause pump 105 to commence causing fluid flow F to flow through flow path FP (e.g., to commence pumping), to cause pump 105 to cease causing fluid flow F to flow through flow path FP (e.g., to cease pumping), and / or to alter a flow rate of fluid flow FP flowing through flow path FP (e.g., by changing a speed of pump 105). In examples, processing circuitry 120 is configured to control pump 105 based on the fluid amount determined using the signal received from sensor 162. For example, processing circuitry 120 may be configured to cause pump 105 to commence pumping fluid flow F.Processing circuitry 120 may be configured to cause pump 105 to cease pumping fluid flow F when processing circuitry 120 determines that the fluid amount (e.g., subsequent to pump 105 commencing) has passed through flow path FP.

[0110] Alternately or in addition, processing circuitry 120 may be configured to control pump 105 based on a flow rate through flow path FP determined using the signal received from sensor 162. For example, processing circuitry 120 may be configured to a pump speed of control pump 105 based on the flow rate through flow path FP. In examples, processing circuitry 120 is configured to cause pump 105 to increase the pump speed to increase the flow rate through flow path FP and / or cause pump 105 to decrease the pump speed to decrease the flow rate through flow path FP.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0111] Conduit 144, bodies 156, processing circuitry 120, and / or pump 105 may be configured to cause fluid flow F to have a flow rate within flow path FP such that a Reynolds number of fluid flow F within flow path FP is less than about 9000 in some examples, less than about 5000 in some examples, and less than about 2000 in some examples. In some examples, conduit 144, bodies 156, processing circuitry 120, and / or pump 105 are configured such that, when a range of Reynolds numbers within the conduit is less than about 9000, the plurality of Strouhal numbers provide a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples . In examples, conduit 144, bodies 156, processing circuitry 120, and / or pump 105 are configured such that, when the flow rate of fluid flow F through flow path FP is less than about 1000 ml / min, and in some examples less than about 500 ml / min, the Reynolds number is less than about 9000 in some examples, less than about 5000 in some examples, and less than about 2000 in some examples.

[0112] In some examples, conduit 144, bodies 156, processing circuitry 120, and / or pump 105 are configured such that a first Strouhal number of fluid flow F, a second Strouhal number of fluid flow F, and a third Strouhal number of fluid flow F define a substantially linear function with respect to a range of Reynolds numbers of fluid flow F. In some examples, the first Strouhal number, the second Strouhal number, and the third Strouhal number are substantially equal (e.g., within about 30% of each other in some examples, within about 15% of each other in some examples, and / or within about 5% of each other in some examples). For example, the first Strouhal number may result when fluid flow F has a first Reynolds number, the second Strouhal number may result when fluid flow F has a second Reynolds number, and the third Strouhal number may result when the fluid flow has a third Reynolds number. Conduit 144, bodies 156, processing circuitry 120, and / or pump 105 may be configured such that the first Strouhal number and the first Reynolds number, the second Strouhal number and the second Reynolds number, and the third Strouhal number and the third Reynolds number define a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples.

[0113] In some examples, processing circuitry 120 is be configured to determine a flow rate using a proximate Strouhal number. For example, conduit 144, bodies 156, processing circuitry 120, pump 105, and / or other components of system 200 may be configured such that a Strouhal number within conduit 144 is relatively constant (e.g., substantially equal) over a range of fluid velocities through conduit 144 provided by pump 105. In examples, the relatively constant Strouhal number may define the proximate value of the Strouhal number (e.g., estimated and / or characterized as a result of bench testing of the system). ProcessingDocket No : A0009202 PCT01 / 1246-061 WOO 1 circuitry 120 may be configured to use the frequency of vortices detachment detected by sensor 162 and determine a flow rate by determining a velocity of the fluid flow F

[0114] In examples, for example as shown in FIG. 3B, conduit wall 146 (e.g., conduit inner surface 148) defines a cross-sectional dimension DC of flow path FP defined in a particular direction (e.g., substantially perpendicular to longitudinal axis L). Bodies 156 (e.g., a first body and / or a second body) may define a cross-sectional dimension DB of bodies 156 in the particular direction. Conduit 144 and / or bodies 156 may be configured such that cross- sectional dimension DB is at least 20% of cross-sectional dimension DC. Flow detector 118 may be configured to position and / or support bodies 156 within flow path FP such that cross- sectional dimension DB is at least 20% of cross-sectional dimension DC. In some examples, bodies 156 extends from a first portion 149 of conduit inner surface 148 (“inner surface first portion 149”) to a second portion 151 of conduit inner surface 148 (“inner surface second portion 151”). Conduit 144 and / or bodies 156 may be configured such that inner surface first portion 149 faces inner surface second portion 151 such that, for example, bodies 156 extend substantially completely across some portion of flow path FP. In some examples, a traverse axis (not shown) perpendicular to and intersecting longitudinal axis L extends through inner surface first portion 149 and inner surface second portion 151. In examples, cross-sectional dimension DC and cross-sectional dimension DB are configured to cause a plurality of Strouhal numbers of fluid flow F and a plurality of Reynolds numbers of fluid flow F to define a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples, when a Reynolds number of fluid flow F is less than about 9000 in some examples, less than about 5000 in some examples, and less than about 2500 in some examples.

[0115] FIG. 4 is a plan view of an example flow detector 164 including a first body 166 and a second body 168, illustrated in accordance with the X-Y-Z axes shown. In FIG. 4A, conduit 144 is illustrated as a cross-section with a cutting plane taken parallel to longitudinal axis L and / or the X-axis. Flow detector 164 is an example of flow detector 118. Bodies 156 include first body 166 and second body 168. Although first body 166 is represented with a first dashed border in FIG. 4 and second body 168 is represented with a second dashed border in FIG. 4, first body 166 may have, include, and / or define any of the characteristics of a first body discussed herein and second body 168 may have, include, and / or define any of the characteristics of a second body discussed herein.

[0116] Flow detector 164 is configured such that first body 166 defines a first flow obstacle within flow path FP defined by conduit 144 and second body 168 defines a secondDocket No : A0009202 PCT01 / 1246-061 WOO 1 flow obstacle within flow path FP. In examples, flow detector 164 is configured to support and / or position first body 166 and / or second body 168 within flow path FP, such that fluid flow F flows around first body 166 and / or second body 168 when fluid flow F flows in downstream direction D. Flow detector 164 is configured to cause fluid flow F to form vortices 160 when fluid flow F flows around first body 166 and second body 168.

[0117] In examples, first body 166 defines a first stagnation feature 170 and a first trailing edge 172. Second body 168 may define a second stagnation feature 174 and a second trailing edge 176. First stagnation feature 170 and / or second stagnation feature 174 may be examples of stagnation feature 158. First trailing edge 172 and / or second trailing edge 176 may be examples of trailing edge 159. For example, first stagnation feature 170 may be configured to cause a first stagnation point in fluid flow F when fluid flow F encounters first stagnation feature 170 (e.g., as fluid flow F flows substantially in downstream direction D). Second stagnation feature 174 may be configured to cause a second stagnation point in fluid flow F when fluid flow F encounters second stagnation feature 174 (e.g., as fluid flow F flows substantially in downstream direction D). In examples, flow detector 164 is configured to support and / or position second body 168 (e.g., second stagnation point 174) downstream of first body 166 (e.g., first trailing edge 172). In examples, second body 168 (e.g., second stagnation point 174) and first body 166 (e.g., first trailing edge 176) are displaced at least by a displacement P substantially parallel to longitudinal axis L.

[0118] First body 166 and second body 168 are configured to cause vortices 160. In examples, first body 166 and second body 168 are configured such that vortices 160 include first vortices 178 and second vortices 180. Each of first vortices 178 and second vortices 180 may exhibit the vorticity, curl, pressure fluctuations, velocity fluctuations, and other fluid dynamics behaviors and / or descriptions attributed to vortices 160. In examples, first body 166 is configured to cause fluid flow F to form first vortices 178 when fluid flow F flows around first body 166 from first stagnation feature 170 to first trailing edge 172. Second body 168 may be configured to cause fluid flow F to form second vortices 180 when fluid flow F flows around second body 168 from second stagnation feature 174 to second trailing edge 176.

[0119] First body 166 may be configured to cause fluid flow F to form first vortices 178 substantially in the vicinity of and / or downstream of first trailing edge 172. Second body 168 may be configured to cause fluid flow F to form second vortices 180 substantially in the vicinity of and / or downstream of second trailing edge 176. Sensor 162 may be configured to sense the movement of fluid flow F caused by first vortices 178 and / or second vortices 180 when fluid flow F flows around first body 166 and second body 168. In examples, sensor 162Docket No : A0009202 PCT01 / 1246-061 WOO 1 is configured to sense the movement of fluid F within second vortices 180 (e.g., substantially in the vicinity of and / or downstream of second trailing edge 176) when fluid flow F flows around first body 166 and second body 168.

[0120] In examples, first body 166 and / or second body 168 define the cross-sectional dimension DB (FIG. 3B). In some examples, first body 166 and / or second body 168 extends from inner surface first portion 149 to inner surface second portion 151. For example, first body 166 may extend from a first section of inner surface first portion 149 to a first section of inner surface second portion 151. Second body 168 may extend from a second section of inner surface first portion 149 to a second section of inner surface second portion 151. In examples, the second section of inner surface first portion 149 is downstream of the first section of inner surface first portion 149. The second section of inner surface second portion 151 may be downstream of the first section of inner surface second portion 151.

[0121] In some examples, bodies 156 (e.g., a first body of bodies 156 and / or a second body of bodies 156) define a cross-sectional area defining a straight edge. In examples, the straight edge defines a characteristic length for a Reynolds number and / or a Strouhal number of fluid flow F. In examples, bodies 156 (e.g., a first body of bodies 156 and / or a second body of bodies 156) are configured such that the straight edge is substantially perpendicular to a direction of fluid flow F. In some examples, the cross-sectional area defines a polygon, such as a triangle or other polygon. For example, FIG. 5 illustrates a body 182 defining a cross-sectional area Al. Body 182 may be configured such that cross-sectional area Al is substantially parallel to longitudinal axis L when flow detector 118, 164 positions and / or supports body 182 within flow path FP. In examples, cross-sectional area Al is bounded by a boundary Bl which includes a straight edge 184 (e.g., a linear portion of boundary Bl). In examples, straight edge 184 is a portion of an area of body 182 (e.g., a planar or curved area) which extends in the Z direction of the X-Y-Z axes shown (e.g., extends into and / or out of the page). Body 182 may be an example of bodies 156 and / or body 166, 168.

[0122] Flow detector 118, 164 may position and / or support body 182 within flow path FP such that straight edge 184 substantially faces fluid flow F when fluid flow F flows through flow path FP. In examples, flow detector 118, 164 positions and / or supports body 182 within flow path FP such that straight edge 184 is substantially perpendicular to and / or intersected by longitudinal axis L. Body 182 may define one or more stagnation features such as stagnation feature 186 defined on straight edge 184 and / or stagnation feature 188 defined by a comer where straight edge 184 meets a second edge 190 (e.g., a second straight edge) of boundary Bl. Although body 182 is depicted in FIG. 4 as positioned and / or supported byDocket No : A0009202 PCT01 / 1246-061 WOO 1 flow detector 118, 164 such that straight edge 184 substantially faces fluid flow F and / or such that straight edge 184 is substantially perpendicular to longitudinal axis L, body 182 may be positioned and / or supported by flow detector 118, 164 such that straight edge 184 has other orientations relative to fluid flow F and / or longitudinal axis L in other examples. Body 182 may define a trailing edge 185, which may be an example of trailing edge 159, 172, 174.

[0123] In some examples, bodies 156 (e.g., the first body of bodies 156 and / or the second body of bodies 156) define a cross-sectional area defining a curved edge. In examples, the cross-sectional area is oval-shaped, substantially circular, or another shape defining a curved edge. For example, FIG. 6 illustrates a body 192 defining a cross-sectional area A2. Body 192 may be configured such that cross-sectional area A2 is substantially parallel to longitudinal axis L when flow detector 118, 164 positions and / or supports body 192 within flow path FP. In examples, cross-sectional area A2 is bounded by a boundary B2 which includes a curved edge 194 (e.g., a curved portion of boundary B2). In examples, curved edge 194 is a portion of an area of body 192 (e.g., a curved or planar area) which extends in the Z direction of the X-Y-Z axes shown (e.g., extends into and / or out of the page). Body 192 may be an example of bodies 156 and / or body 166, 168.

[0124] Flow detector 118, 164 may position and / or support body 192 within flow path FP such that curved edge 194 substantially faces fluid flow F when fluid flow F flows through flow path FP. In examples, flow detector 118, 164 positions and / or supports body 194 within flow path FP such that longitudinal axis L intersects curved edge 194. Body 192 may define one or more stagnation features such as stagnation feature 196 and / or stagnation feature 198 defined by curved edge 194. Although body 192 is depicted in FIG. 6 as positioned and / or supported by flow detector 118, 164 such that curved edge 194 substantially faces fluid flow F and / or such that longitudinal axis L intersects curved edge 194, body 192 may be positioned and / or supported by flow detector 118, 164 such that curved edge 194 has other orientations relative to fluid flow F and / or longitudinal axis L in other examples. Body 192 may define a trailing edge 195, which may be an example of trailing edge 159, 172, 174.

[0125] In some examples, bodies 156 (e.g., the first body of bodies 156 and / or the second body of bodies 156) define a cross-sectional area defining a curved edge and a straight edge. In examples, the cross-sectional area defines a cylindric shape. For example, FIG. 7 illustrates a body 204 defining a cross-sectional area A3. In examples, body 204 is a cylindric section defining cross-sectional area A3. Body 204 may be configured such that cross- sectional area A3 is substantially parallel to longitudinal axis L when flow detector 118, 164 positions and / or supports body 204 within flow path FP. In examples, cross-sectional area A3Docket No : A0009202 PCT01 / 1246-061 WOO 1 is bounded by a boundary B3 which includes a curved edge 206 and a straight edge 208. Curved edge 206 may be an example of curved edge 194 (FIG. 6). Straight edge 208 may be an example of straight edge 184 (FIG. 5). Body 204 may define first stagnation feature 170. In examples, first stagnation feature 170 is defined by a comer where straight edge 208 meets curved edge 206. Body 204 may define trailing edge 172 (e.g., where straight edge 208 meets curved edge 206). Body 204 may be an example of bodies 156 and / or body 166, 168.

[0126] In some examples, bodies 156 include body 204 (e.g., as a first body) and a body 212 (e.g., as a second body). Body 212 may be an example of bodies 156 and / or body 166, 168. In examples, body 212 defines a cross-sectional area A4 bounded by a boundary B4 which includes a curved edge 214 and a straight edge 216. In examples, body 212 is a cylindric section defining cross-sectional area A4. Body 212 may be configured such that cross-sectional area A4 is substantially parallel to longitudinal axis L when flow detector 118, 164 positions and / or supports body 212 within flow path FP. Curved edge 214 may be an example of curved edge 194 (FIG. 6). Straight edge 216 may be an example of straight edge 184 (FIG. 5). In examples, body 212 defines one or more stagnation features such as stagnation feature 218 defined by a comer where straight edge 216 meets curved edge 214.

[0127] In examples, body 212 is displaced from body 204 by a displacement DP. For example, straight edge 208 may be defined by a first surface 220 (e.g., a first planar surface) of body 204 extending in the Z direction of the X-Y-Z axes shown (e.g., extending into and / or out of the page). Straight edge 216 may be defined by a second surface 222 (e.g., a second planar surface) of body 204 extending in the Z direction of the X-Y-Z axes shown (e.g., extending into and / or out of the page). Body 204 and body 212 may be configured such that second surface 222 is displaced from first surface 220 by a displacement DP when body 204 and body 212 are positioned and / or supported by flow detector 118, 164.

[0128] In examples, body 204 and body 212 are configured such that fluid flow F flows between first surface 220 and second surface when flow detector 118, 164 positions and / or supports body 204 and body 212 within flow path FP. In some examples, longitudinal axis L extends between first surface 220 and second surface when flow detector 118, 164 positions and / or supports body 204 and body 212 within flow path FP. In some examples, the displacement DP is substantially perpendicular to longitudinal axis L. In examples, the displacement DP defines a gap G between first surface 220 and second surface 222. In examples, gap G, first surface 220, and / or second surface 222 extends substantially across flow path FP (e.g., in a direction substantially parallel to the Z axis). For example, gap G, first surface 220, and / or second surface 222 may extend from a primary portion of conduitDocket No : A0009202 PCT01 / 1246-061 WOO 1 inner surface 148 (FIG. 4) to a secondary portion of conduit inner surface 148 which faces the primary portion.

[0129] Bodies 156 (e.g., first body 166 and / or second body 168 (FIG. 4)) may include body 182 (FIG. 5), body 192 (FIG. 6), body 204 (FIG. 7), and / or body 212 (FIG. 7), singly or in any combination. In examples, bodies 156 include first body 166 (e.g., one of body 182, body 192, body 204, and / or body 212) and second body 168 (another of body 182, body 192, body 204, and / or body 212). In examples, first body 166 and second body 168 are configured such that longitudinal axis L extends through first body 166 and second body 168 when flow detector 118, 164 positions and / or supports first body 166 and second body 168 within flow path FP.

[0130] As an example, FIG 8. schematically illustrates a flow detector 224 wherein bodies 156 include a first body 226 configured similarly to body 182 (FIG. 5) and a second body 228 configured similarly to body 182. Conduit 144 defines cross-sectional dimension DC of flow path FP. First body 226 defines first stagnation feature 170 and first trailing edge 172. Second body 228 defines second stagnation feature 174 and second trailing edge 176. Flow detector 224 is an example of flow detector 118, 164.

[0131] First body 226 may define a first cross-sectional dimension DA. In examples, first body 226 defines a cross-sectional area similar to cross-sectional area Al of body 182. A straight edge similar to straight edge 184 (FIG. 5) may define first cross-sectional dimension DA. Second body 228 may define a second cross-sectional dimension DB. In examples, second body 228 defines another cross-sectional area similar to cross-sectional area Al of body 182. Another straight edge similar to straight edge 184 may define second cross- sectional dimension DB. In some examples, first cross-sectional dimension DA and / or second cross-sectional dimension DB is greater than or equal to 20% of cross-sectional dimension DC. In examples, first cross-sectional dimension DA is substantially equal to second cross- sectional dimension DB. In other examples, first cross-sectional dimension DA may be different than second cross-sectional dimension DB

[0132] In some examples, first body 226 and / or second body 228 define a length LB substantially parallel to longitudinal axis L. For example, first body 226 may define length LB from first stagnation feature 170 to first trailing edge 172. Second body 228 may define a length from second stagnation feature 174 to second trailing edge 176. In some examples, the length from second stagnation feature 174 to second trailing edge 176 may be substantially equal to length LB. In other examples, the length from second stagnation feature 174 to second trailing edge 176 may different than length LB. In examples, first body 226Docket No : A0009202 PCT01 / 1246-061 WOO 1 and / or second body 228 are configured such that a ratio of length LB to one of first cross- sectional dimension DA or second cross-sectional dimension DB is greater than or equal to about 2.5 and less than or equal to about 5.5. In some examples, first stagnation feature 170 is displaced from second stagnation feature by a distance H (e.g., a distance substantially parallel to longitudinal axis L). First body 226 and / or second body 228 may be configured such that a ratio of the distance H to one of first cross-sectional dimension DA or second cross-sectional dimension DB is greater than or equal to about 0.8 and less than or equal to about 1.6.

[0133] FIG 9. schematically illustrates a flow detector 230 wherein bodies 156 include body 204 (e.g., as a first body) (FIG. 7) and body 212 (e.g., as a second body) (FIG. 7). Conduit 144 defines cross-sectional dimension DC of flow path FP. Body 204 is displaced from body 212 by the displacement DP. Longitudinal axis L extends through flow path FP and may extend through gap G defined by displacement DP. Body 204 defines first stagnation feature 170 and first trailing edge 172. Body 212 defines second stagnation feature 174 and second trailing edge 176. Flow detector 230 is an example of flow detector 118, 164.

[0134] In examples, body 204 (e.g., cross-sectional area A3 (FIG. 7)) defines a first cross-sectional dimension DI. Body 212 (e.g., cross-sectional area A4 (FIG. 7)) may define a second cross-sectional dimension D2. In examples, first cross-sectional dimension DI and / or second cross-sectional dimension D2 are substantially parallel to the displacement DP. For example, body 204 may define first cross-sectional dimension DI in a first direction (e.g., a first direction substantially perpendicular to longitudinal axis L), body 212 may define second cross-sectional dimension D2 in the first direction, and body 204 and body 212 may define the displacement DP in the first direction. In examples, first cross-sectional dimension DI, displacement DP, and second cross-sectional dimension D2 define the linear dimension LD (e.g., a linear dimension substantially perpendicular to longitudinal axis L). In examples, linear dimension LD is greater than or equal to at least 20% of cross-sectional dimension DC. In some examples, displacement DP is greater than or equal to at least 30% of linear dimension LD.

[0135] In some examples, flow detector 118, 164 comprises a third body either upstream of the first body and the second body or downstream of the first body and the second body. For example, FIG 10. schematically illustrates a flow detector 232 with bodies 156 comprising a third body 234 upstream of a first body 236 and a second body 238. FIG 11 schematically illustrates a flow detector 233 with bodies 156 comprising third body 234 downstream of first body 236 and second body 238. Third body 234 defines a stagnationDocket No : A0009202 PCT01 / 1246-061 WOO 1 feature 240, first body 236 defines a stagnation feature 242, and second body 238 defines a stagnation feature 244.

[0136] In examples, third body 234 defines first cross-sectional dimension DA. First body 236 and second body 238 may define displacement LD. In some examples, stagnation feature 240 is displaced from stagnation feature 242 and / or stagnation feature 244 by a distance HL (e.g., a distance substantially parallel to longitudinal axis L). Third body 234, first body 236, and / or second body 238 may be configured such that a ratio of the distance HL to one of first cross-sectional dimension DA or displacement LD is greater than or equal to about 0.8 and less than or equal to about 1.6.

[0137] As a further example, FIG 12. schematically illustrates a flow detector 234 with bodies 156 comprising a third body 246 upstream of first body 236 and second body 238. FIG 13 schematically illustrates a flow detector 235 with bodies 156 comprising third body 246 downstream of first body 236 and second body 238. Third body 246 defines a stagnation feature 248. In examples, third body 246 defines a cross-sectional dimension D3. In examples, third body 246 defines a cross-sectional area similar to cross-sectional area A2 of body 192 (FIG. 6). The cross-sectional area similar to cross-sectional area A2 may define cross-sectional dimension D3. In examples, cross-sectional dimension D3 is substantially equal to displacement LD. In examples, cross-sectional area D3 is substantially perpendicular to longitudinal axis L. A curved edge similar to curved edge 194 may define stagnation feature 248. In some examples, stagnation feature 248 is displaced from stagnation feature 242 and / or stagnation feature 244 by the distance HL. Third body 246, first body 236, and / or second body 238 may be configured such that a ratio of the distance HL to one of cross- sectional dimension D3 or displacement DL is greater than or equal to about 0.8 and less than or equal to about 1.6.

[0138] In the examples of FIG. 10, FIG. 11, FIG. 12, and FIG. 13, first body 236 is configured similarly to body 204, second body 238 is configured similarly to body 212, third body 234 is configured similarly to body 182, and third body 246 is configured to similarly to body 192, although this is not required. A first body of flow detector 232, 233, 234, 236 may be configured similarly to any of body 182, body 192, body 204, or another body defining a stagnation feature, a second body of flow detector 232, 233, 234, 235 may be configured similarly to any of body 182, body 192, body 204, body 212, or another body defining a stagnation feature, and a third body of flow detector 232, 233, 234, 235 may be configured similarly to any of body 182, body 192, body 204, or another body defining a stagnationDocket No : A0009202 PCT01 / 1246-061 WOO 1 feature. Stagnation feature 240, stagnation feature 242, stagnation feature 244, and / or stagnation feature 248 may be examples of stagnation feature 158.

[0139] FIG. 14 illustrates an example plurality of Strouhal numbers 252 of fluid flow F versus Reynolds numbers of fluid flow F which may result when flow detector 118, 141, 143, 164, 224, 230, 232, 233, 234, 235 (“flow detector 118-235”) causes fluid flow F to flow through flow path FP, and illustrates a second example plurality of Strouhal numbers 254 of fluid flow F versus Reynolds numbers of fluid flow F which may result when flow detector 118-235 causes fluid flow F to flow through flow path FP. FIG. 15 illustrates a third example plurality of Strouhal numbers 256 of fluid flow F versus Reynolds numbers of fluid flow F which may result when flow detector 118-235 causes fluid flow F to flow through flow path FP, a fourth example plurality of Strouhal numbers 258 of fluid flow F versus Reynolds numbers of fluid flow F which may result when flow detector 118-235 causes fluid flow F to flow through flow path FP, and a fifth example plurality of Strouhal numbers 260 of fluid flow F versus Reynolds numbers of fluid flow F which may result when flow detector 118— 235 causes fluid flow F to flow through flow path FP. In examples, the plurality of Strouhal numbers 252 is caused by a flow detector 118-235 having a first example of bodies 156, the second plurality of Strouhal numbers 254 is caused by a flow detector 118-235 having a second example of bodies 156 different from the first example, the third plurality of Strouhal numbers 256 is caused by a flow detector 118-235 having a third example of bodies 156 different from the first example and the second example, the fourth plurality of Strouhal numbers 258 is caused by a flow detector 118-235 having a fourth example of bodies 156 different from the first example, the second example, and the third example, and / or the fifth plurality of Strouhal numbers 260 is caused by a flow detector 118-235 having a fifth example of bodies 156 different from the first example, the second example, the third example, and the fourth example.

[0140] Referring to FIG. 14, flow detector 118-235 may be configured to cause the plurality of Strouhal numbers 252 or a second plurality of Strouhal numbers 254 as fluid flow F flows within conduit 144 and over bodies 156, first body 166, 204, 226, 234 (“first body 166-234”), second body 168, 212, 228, 238 (“second body 168-238”), and / or third body 234, 246.

[0141] System 100, 200 may be configured to cause the plurality of Strouhal numbers 252 to substantially define a correlation (e.g., a function) with respect to a Reynolds number of fluid flow F. In examples, system 100, 200 (e.g., processing circuitry 120) is configured to detect the movement of fluid flow F (e.g., by detecting a frequency indicative of the StrouhalDocket No : A0009202 PCT01 / 1246-061 WOO 1 number) and determine a velocity (e.g., a flow rate) of fluid flow F which causes the frequency (e.g., causes the Strouhal number). In examples, system 100, 200 determines the velocity using a proximate Strouhal number indicative of the plurality of Strouhal numbers 252. In examples, the proximate Strouhal number is a statistical parameter (e.g., an average or other statistical parameter) describing the plurality of Strouhal numbers 252.

[0142] For example, flow detector 118-235 may be configured such that fluid flow F has a Strouhal number SI when fluid flow F has a Reynolds number of Rl, has a Strouhal number S2 when fluid flow F has a Reynolds number of R2, has a Strouhal number S3 when fluid flow F has a Reynolds number of R3, has a Strouhal number S4 when fluid flow F has a Reynolds number of R4, and has a Strouhal number SN when fluid flow F has a Reynolds number of RN. Flow detector 118-235 may be configured such that Strouhal numbers SI, S2, S3, S4, . . . , SN are described by a correlation Cl relating a specific Strouhal number of fluid flow F to a specific Reynolds number of fluid flow F. In some examples, the correlation Cl is continuous, such that correlation Cl describes a specific parameter indicative of a Reynolds number (e.g., a flow rate of fluid flow F) for any specific parameter indicative of a Strouhal number (e.g., a frequency of fluid movement) in a range between and including SI and SN. Flow detector 118-235 may be configured to cause Strouhal numbers SI, S2, S3, S4, . . . , SN and Reynolds numbers Rl, R2, R3, R4, . . . , RN to define a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples.

[0143] In some examples, the correlation Cl is may be defined by a plurality of separate correlations defined over one or more intervals, such as an interval between SI and S2, an interval between S2 and S3, an interval between S3 and S4, and / or another interval. In examples, the correlation Cl may be a linear function over one or more intervals. Hence, flow detector 118-235 (e.g., the individual dimensions of and / or relative dimensions among conduit 144, bodies 156, first body 166-234, second body 168-238, third body 234, 246, and / or other portions of system 100, 200) may be configured such that correlation Cl relates a specific Strouhal number of fluid flow F to a specific Reynolds number of fluid flow F Flow detector 118-235 (e.g., processing circuitry 120) may be configured to detect the movement of fluid flow F (e.g., by detecting a frequency indicative of the flow velocity according to the associated Strouhal number) and determine a velocity (e.g., a flow rate) of fluid flow F using the frequency and the proximate value of the Strouhal number indicative of the plurality of Strouhal numbers 252.

[0144] Flow detector 118-235 may be configured to define any correlation relating a specific Strouhal number of fluid flow F to a specific Reynolds number of fluid flow F ForDocket No : A0009202 PCT01 / 1246-061 WOO 1 example, a first flow detector 118-235 may be configured such that the correlation Cl relates the second plurality of Strouhal numbers 254 including Strouhal numbers SI, S2, S3, S4, . . . , SN to Reynolds numbers Rl, R2, R3, R4, . . . , RN when bodies 156 include a specific first body and a specific second body. A second flow detector 118-235 may be configured such that a correlation C2 relates a plurality of Strouhal numbers S5, S6, S7, S8, . . . , SM to Reynolds numbers Rl, R2, R3, R4, . . . , RN when bodies 156 include a particular first body different from the specific first body and a particular second body different from the specific second body. Flow detector 118-235 (e.g., processing circuitry 120) may be configured to detect the movement of fluid flow F and determine a flow rate of fluid flow F based on the correlation Cl when the first flow detector 118-235 detects the movement of fluid flow F, and / or configured to detect the movement of fluid flow F and determine a flow rate of fluid flow F based on the correlation C2 when the second flow detector 118-235 detects the movement of fluid flow F.

[0145] In examples, system 100, 200 is configured to cause fluid flow F to have a flow rate such that a Strouhal number of fluid flow F is relatively constant over a range of Reynolds numbers of fluid flow F. For example, FIG. 15 illustrates a third example plurality of Strouhal numbers 256 of fluid flow F versus Reynolds numbers of fluid flow F which may result when flow detector 118-235 causes fluid flow F to flow through flow path FP, illustrates a fourth example plurality of Strouhal numbers 258 of fluid flow F versus Reynolds numbers of fluid flow F which may result when flow detector flow detector 118— 235 causes fluid flow F to flow through flow path FP, and illustrates a fifth example plurality of Strouhal numbers 260 of fluid flow F versus Reynolds numbers of fluid flow F which may result when flow detector flow detector 118-235 causes fluid flow F to flow through flow path FP. The third plurality of Strouhal numbers 256 includes Strouhal numbers S 10, SI 1, S12, S13, . . . , SM which result for Reynolds numbers R5, R6, R7, R8, . . . , RM respectively. The fourth plurality of Strouhal numbers 258 includes Strouhal numbers S14, S15, S16, S17, . . . , SP which result for Reynolds numbers R5, R6, R7, R8, . . . , RM respectively. The fifth plurality of Strouhal numbers 260 includes Strouhal numbers SI 8, S19, S20, S21, . . . , SR which result for Reynolds numbers R5, R6, R7, R8, . . . , RM respectively.

[0146] Flow detector 118-235 may be configured to cause Strouhal numbers S10, SI 1, S12, S13, . . . , SL and Reynolds numbers Rl, R2, R3, R4, . . . , RN to define a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples. Flow detector 118-235 may be configured to cause Strouhal numbers S14, S15, S16, S17, . . .Docket No : A0009202 PCT01 / 1246-061 WOO 1, SP and Reynolds numbers Rl, R2, R3, R4, . . . , RN to define a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples. Flow detector 118-235 may be configured to cause Strouhal numbers S18, S19, S20, S21, . . . , SR and Reynolds numbers Rl, R2, R3, R4, . . . , RN to define a Coefficient of Determination (R2) of at least 0.9 in some examples, and at least 0.95 in some examples. The relatively constant Strouhal numbers of the third plurality of Strouhal numbers 256, the fourth plurality of Strouhal numbers 258, and / or the fifth plurality of Strouhal numbers 260 over the range of Reynolds numbers including Reynolds numbers Rl, R2, R3, R4, . . . , RN, may improve an accuracy of a proximate Strouhal number expected to occur over the range of Reynolds numbers, and may improve an accuracy of a flow rate determined using processing circuitry 120 and / or sensor 162. In some examples, the proximate Strouhal number is an average of a plurality of Strouhal numbers (e.g., an average of one of the plurality of Strouhal numbers 252, the second plurality of Strouhal numbers 254, the third plurality of Strouhal numbers 256, the fourth plurality of Strouhal numbers 258, or the fifth plurality of Strouhal numbers 260).

[0147] Depending on flow rates, solute composition, and other parameters, the geometrical configuration (e.g., dimensions) of flow detector 118-235 may be designed to meet the specific application requirements of its intended application. For example, the provided dimensions can be suitable for a flow rate of less than or equal to about 1000 ml / min, such as about 400 mL / min. However, the specific dimensions can vary according to the flow rate and the physical properties of materials within system 100, 200, such as solid concentrates, liquid concentrates, and / or other materials, according to the maximum allowable operating pressure. In some examples, bodies 156, first body 166-234, second body 168-238, and / or third body 234, 246 may be of a single injection-molded piece of material. Each of the noted features of bodies 156, first body 166-234, second body 168-238, and / or third body 234, 246 may be made integrally from the single injection molded piece.

[0148] Processing circuitry 120 may include fixed function circuitry and / or programmable operating circuitry. In examples, processing circuitry 120 includes circuitry configured to perform one or more functions of operating circuitry, such as sensing circuitry, processing circuitry, switching circuitry, communication circuitry, and / or other circuitries. Processing circuitry 120, as well as other processors, operating circuitry, controllers, control circuitry, processing circuitry, and the like, described herein, may include any combination of integrated circuitry, discrete logic circuity, analog circuitry, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuitsDocket No : A0009202 PCT01 / 1246-061 WOO 1(ASICs), or field-programmable gate arrays (FPGAs). In some examples, processing circuitry 120 includes multiple components, such as any combination of one or more microprocessors, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuitry, and / or analog circuitry.

[0149] Functions attributed to processing circuitry 120 may be embodied as software, firmware, hardware or any combination thereof. Processing circuitry 120 may include, for instance, a variety of capacitors, transformers, switches, and the like configured to perform the functions of processing circuitry 120. In examples, processing circuitry 120 may be configured to communicate with another device, such as pump 105, 108, valve 113, 124, 126, detector 111, 128, 130, purification module 103, sterilization module 106, heater 109, and / or other system and / or components of system 100, 200. Processing circuitry 120 may include any suitable hardware, firmware, software or any combination thereof for communicating with another device. In addition, processing circuitry 120 may communicate with a networked computing device and a computer network.

[0150] System 100, 200 (e.g., processing circuitry 120) can also include memory configured to store program instructions, such as software, which may include one or more program modules, which are executable by processing circuitry 120. The program instructions may be embodied in software and / or firmware. The memory can include any volatile, non-volatile, magnetic, optical, or electrical media, such as a random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), ferroelectric RAM (FRAM), flash memory, or any other digital media. In some examples, the memory includes computer-readable instructions that, when executed by processing circuitry 120 cause processing circuitry 120 to perform various functions described herein and / or other functions of processing circuitry 120.

[0151] Communication links 117, 121, 123, 125, 127, 145, 147 (“communication links 117-147”) and / or other communication links of system 100, 200 may be hard-line and / or wireless communications links. In some examples, communication links 117-147 and / or other communication links may comprise some portion of processing circuitry 120. In some examples, communication links 117-147 and / or other communication links comprise a wired connection, a wireless Internet connection, a direct wireless connection such as wireless LAN, Bluetooth™, Wi-Fi™, and / or an infrared connection. Communication links 117-147 and / or other communication links may utilize any wireless or remote communication protocol.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0152] As used here, when a first portion of a system (e.g., system 100, 200) is substantially parallel to a second portion of or an axis defined by the system, this may mean the first portion is parallel or nearly parallel to the second portion or the axis to the extent permitted by manufacturing tolerances. In some examples, when the first portion is substantially parallel to the second portion or the axis, this may mean a first vector defined by the first component of the system defines an angle of less than 10 degrees, in some examples less than 5 degrees, and in some examples less than 1 degree, with a second vector defined by the second component or the axis. When a first portion is substantially perpendicular to the second portion of or the axis defined by the system, this may mean the first portion is perpendicular or nearly perpendicular to the second portion or the axis to the extent permitted by manufacturing tolerances. In some examples, when the first portion is substantially perpendicular to the second portion or the axis, this may mean the first vector defined by the first component defines an angle of less than 80 degrees, in some examples less than 85 degrees, and in some examples less than 89 degrees, with the second vector defined by the second component or the axis.

[0153] As used here, when a first quantity described for a system (e.g., system 100, 200) is substantially equal to a second quantity described for the system or another system, this may mean the first quantity is equal to or nearly equal to the second quantity to the extent permitted by manufacturing tolerances. In some examples, when the first quantity is substantially equal to the second quantity, this may mean a difference between the first quantity and the second quantity is less than 10% of, in some examples less than 5% of, and in some examples less than 1% of, the first quantity or the second quantity.

[0154] As used here, when a first portion of a system (e.g., system 100, 200) supports a second portion of the system, this means that when the second portion causes a first force to be exerted on the first portion, the first portion causes a second force to be exerted on the second portion in response to the first force. The first force and / or second force may be a contact force and / or an action-at-a-distance force. For example, first force and / or second force may be mechanical force, a magnetic force, a gravitational force, or some other type of force. The first portion of the system may be a portion of the system or a portion of a component of the system. The second portion of the system may be another portion of the system or another portion of the same component or a different component. In some examples, when the first portion of the system supports the second portion of the system, this may mean the second portion is mechanically supported by and / or mechanically connected to the first portion.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0155] FIG. 16 is a flow diagram illustrating an example technique for determining a flow rate of a fluid. While the technique is described with reference to system 100, 200 and flow detector mixing flow detector 118-235 described herein, the technique may be used with other components and / or systems in other examples.

[0156] The technique includes receiving, by processing circuitry 120 of flow detector 118-235, a signal indicative of movement of a fluid flow F (1602). In examples, the signal is indicative of pressure fluctuations of fluid flow F and / or velocity fluctuations of fluid flow F caused by and / or indicative of the movement of fluid flow F. In examples, the movement of fluid flow F is caused by vortex shedding of fluid flow F. In examples, fluid flow F flows through a flow path FP defined by a conduit 144.

[0157] Fluid flow F may flow around bodies 156 positioned within and / or supported by conduit 144 when fluid flow F flows within flow path FP. In examples, fluid flow F flows around one or more of first body 166-234, second body 168-238, and / or third body 234, 246. In examples, first body 166-234, second body 168-238, and / or third body 234, 246 causes the movement of fluid flow F (e.g., the vortex shedding) as fluid flow F flows around first body 166-234, second body 168-238, and / or third body 234, 246. For example, first body 166-234, second body 168-238, and / or third body 234, 246 may cause fluid flow F to form vortices 160 as fluid flow F flows around first body 166-234, second body 168-238, and / or third body 234, 246. In some examples, fluid flow F flows around first body 166-234 and second body 168-238 when fluid flow F flows within flow path FP. In examples, first body 166-234, second body 168-238, and / or third body 234, 246 may cause fluid flow F to form first vortices 178 and second vortices 180.

[0158] Processing circuity 120 may receive the signal from a sensor 162. In examples, sensor 162 detects the movement of fluid flow F downstream of a stagnation features 158, 170, 174, 186, 188, 196, 198, 242, 244, 248 (“stagnation feature 158-248”). In examples, sensor 162 detects the movement of fluid flow F downstream of a trailing edge 159, 172, 176, 185, 195 (“trailing edge 159-195”). Flow detector 118-235 may cause the movement of fluid flow F as fluid flow F flows from stagnation feature 158-248 to trailing edge 159-195. In examples, sensor 162 detects movement of fluid flow F in the vicinity of and / or downstream of trailing edge 159-195. In examples, sensor 162 detects a pressure fluctuation and / or a velocity fluctuation of fluid flow F within, for example, vortices 160, 178, 180.

[0159] The technique includes determining, by processing circuitry 120, a flow rate of fluid flow F using a frequency indicative of the movement of fluid flow F (1604). In examples, processing circuitry 120 determines the frequency using the signal provided byDocket No : A0009202 PCT01 / 1246-061 WOO 1 sensor 162. In some examples, processing circuitry 120 determines a frequency indicative of a Strouhal number of fluid flow F and determines a flow rate of fluid flow F which causes the frequency based on a correlation Cl, C2 between the Strouhal number of fluid flow F and a Reynolds number of fluid flow F.

[0160] The following examples are illustrative of the techniques described herein. The following examples may be combined with any of other examples disclosed herein.

[0161] Example 1. A system comprising: a conduit including a conduit wall defining a flow path for a fluid flow of a fluid; a flow detector including one or more bodies within the flow path, wherein the conduit is configured to cause the fluid flow to flow around the one or more bodies when the fluid flow flows within the flow path, and wherein the one or more bodies define a stagnation feature; a sensor configured to sense a movement in the fluid when the fluid flows around the one or more bodies, wherein the sensor is configured to sense the movement at a location downstream of the stagnation feature; and processing circuitry configured to: receive a signal indicative of the movement from the sensor, determine a frequency of the movement using the signal, determine a flow rate of the fluid flow within the conduit based on the frequency, and determine an amount of the fluid delivered to a container based on the flow rate of the fluid flow.

[0162] Example 2. A flow detector comprising: a conduit including a conduit wall defining a flow path for a fluid flow; a first body defining a first obstacle within the flow path; a second body defining a second obstacle within the flow path, wherein the conduit is configured to cause the fluid flow to flow around the first body and the second body when the fluid flow flows within the flow path, and a sensor configured to sense a movement in the fluid of the fluid flow when the fluid flows around the first body and around the second body, wherein the sensor is configured to sense the movement in the fluid at a location downstream of a stagnation feature defined by the second body, the stagnation feature configured to cause a stagnation point in the fluid flow when the fluid flows around the second body, and processing circuitry configured to: receive a signal indicative of the movement in the fluid from the sensor, determine a frequency of the movement in the fluid based on the signal, and determine a flow rate of the fluid flow within the flow path based on the frequency.

[0163] Example 3. The flow detector of claim 2, wherein: the conduit wall defines a conduit cross-sectional dimension of the flow path, the conduit cross-sectional dimension being measured in a direction, the first body defines a first cross-sectional dimension measured in the direction, the second body defines a second cross-sectional dimension measured in the direction, and the conduit cross-sectional dimension, the first cross-sectionalDocket No : A0009202 PCT01 / 1246-061 WOO 1 dimension, and the second cross-sectional dimension are configured to cause the fluid flow to have the Reynolds number less than or equal to about 9000.

[0164] Example 4. The flow detector of claim 2 or claim 3, wherein the movement in the fluid is caused by vortex shedding of the fluid flow, and wherein the processing circuitry is configured to determine the flow rate based on the frequency and a proximate Strouhal number of the fluid flow within the conduit.

[0165] Example 5. The flow detector of any of claims 2-4, wherein the first body extends from a first portion of an inner surface of the conduit wall to a second portion of the inner surface facing the first portion, and wherein the second body extends from a third portion of the inner surface to a fourth portion of the inner surface facing the third portion.

[0166] Example 6. The flow detector of any of claims 2-5, wherein the conduit defines an inlet portion of the flow path configured to receive the fluid flow and an outlet portion of the flow path configured to discharge the fluid flow, wherein the conduit defines a longitudinal axis extending through the inlet portion and the outlet portion, and wherein the longitudinal axis intersects the first body and the second body.

[0167] Example 7. The flow detector of claim 6, wherein the first body defines a first cross-sectional dimension measured in a direction, the second body defines a second cross- sectional dimension measured in the direction, and at least one of the first cross-sectional dimension or the second cross-sectional dimension is at least 20% of the conduit cross- sectional dimension.

[0168] Example 8. The flow detector of any of claims 2-7, wherein the first body comprises a first cylindric section, wherein the second body comprises a second cylindric section, and wherein the first body, the second body, and the conduit wall are configured to cause the fluid flow to flow between the first cylindric section and the second cylindric section when the fluid flows through the flow path.

[0169] Example 9. The flow detector of claim 8, wherein the first cylindric section defines a first planar surface and the second cylindric surface defines a second surface substantially parallel to the first surface, and wherein the first body, the second body, and the conduit wall are configured to cause the fluid flow to flow between the first surface and the second surface when the fluid flows through the flow path.

[0170] Example 10. The flow detector of claim 8 or claim 9, wherein the first cylindric section is a first section of a particular cylinder and the second cylindric section is a second section of the particular cylinder.Docket No : A0009202 PCT01 / 1246-061 WOO 1

[0171] Example 11. The flow detector of any of claims 8-10, wherein the first cylindric section defines the first cross-sectional dimension in a first direction and the second cylindric section defines the second cross-sectional dimension in the first direction, and the first cross- sectional dimension, the second cross-sectional dimension, and a displacement between the first body and the second body define a linear dimension LD measured in the first direction.

[0172] Example 12. The flow detector of claim 11, wherein the displacement between the first body and the second body is at least 20% of the conduit cross-sectional dimension.

[0173] Example 13. The flow detector of claim 11 or claim 12, wherein the displacement between the first body and the second body is at least 30% of the linear dimension LD.

[0174] Example 14. A method comprising: receiving, by processing circuitry, a signal indicative of movement of a fluid flow from a sensor, wherein the movement is caused when the fluid flows around a first body and around a second body within a flow path defined by a conduit, wherein the fluid flow has a Reynolds number less than or equal to about 9000 within the conduit, and wherein the sensor senses the movement at a location downstream of a stagnation feature of the second body, the stagnation feature configured to cause a stagnation point in the fluid flow when the fluid flows around the second body, and determining, by the processing circuitry, a frequency of the movement; and determining, by the processing circuitry, a flow rate of the fluid flow within the flow path based on the frequency.

[0175] Example 15. The method of claim 14, wherein the fluid flow has a Strouhal number less than or equal to about 0.3 within the conduit.

[0176] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

Docket No : A0009202 PCTO 1 / 1246-061 WOO 1WHAT IS CLAIMED IS:

1. A system comprising: a conduit including a conduit wall defining a flow path for a fluid flow of a fluid; a flow detector including one or more bodies within the flow path, wherein the conduit is configured to cause the fluid flow to flow around the one or more bodies when the fluid flow flows within the flow path, and wherein the one or more bodies define a stagnation feature; a sensor configured to sense a movement in the fluid when the fluid flows around the one or more bodies, wherein the sensor is configured to sense the movement at a location downstream of the stagnation feature; and processing circuitry configured to: receive a signal indicative of the movement from the sensor, determine a frequency of the movement using the signal, determine a flow rate of the fluid flow within the conduit based on the frequency, and determine an amount of the fluid delivered to a container based on the flow rate of the fluid flow.

2. A flow detector comprising: a conduit including a conduit wall defining a flow path for a fluid flow; a first body defining a first obstacle within the flow path; a second body defining a second obstacle within the flow path, wherein the conduit is configured to cause the fluid flow to flow around the first body and the second body when the fluid flow flows within the flow path; a sensor configured to sense a movement in the fluid of the fluid flow when the fluid flows around the first body and around the second body, wherein the sensor is configured to sense the movement in the fluid at a location downstream of a stagnation feature defined by the second body, the stagnation feature configured to cause a stagnation point in the fluid flow when the fluid flows around the second body; and processing circuitry configured to: receive a signal indicative of the movement in the fluid from the sensor, determine a frequency of the movement in the fluid based on the signal, and determine a flow rate of the fluid flow within the flow path based onDocket No : A0009202 PCTO 1 / 1246-061 WOO 1 the frequency.

3. The flow detector of claim 2, wherein: the conduit wall defines a conduit cross-sectional dimension of the flow path, the conduit cross-sectional dimension being measured in a direction, the first body defines a first cross-sectional dimension measured in the direction, the second body defines a second cross-sectional dimension measured in the direction, and the conduit cross-sectional dimension, the first cross-sectional dimension, and the second cross-sectional dimension are configured to cause the fluid flow to have the Reynolds number less than or equal to about 9000.

4. The flow detector of claim 2 or claim 3, wherein the movement in the fluid is caused by vortex shedding of the fluid flow, and wherein the processing circuitry is configured to determine the flow rate based on the frequency and a proximate Strouhal number of the fluid flow within the conduit.

5. The flow detector of any of claims 2-4, wherein the first body extends from a first portion of an inner surface of the conduit wall to a second portion of the inner surface facing the first portion, and wherein the second body extends from a third portion of the inner surface to a fourth portion of the inner surface facing the third portion.

6. The flow detector of any of claims 2-5, wherein the conduit defines an inlet portion of the flow path configured to receive the fluid flow and an outlet portion of the flow path configured to discharge the fluid flow, wherein the conduit defines a longitudinal axis extending through the inlet portion and the outlet portion, and wherein the longitudinal axis intersects the first body and the second body.

7. The flow detector of claim 6, wherein the first body defines a first cross-sectional dimension measured in a direction, the second body defines a second cross-sectional dimension measured in the direction, and at least one of the first cross-sectional dimension orDocket No : A0009202 PCT01 / 1246-061 WOO 1 the second cross-sectional dimension is at least 20% of the conduit cross-sectional dimension.

8. The flow detector of any of claims 2-7, wherein the first body comprises a first cylindric section, wherein the second body comprises a second cylindric section, and wherein the first body, the second body, and the conduit wall are configured to cause the fluid flow to flow between the first cylindric section and the second cylindric section when the fluid flows through the flow path.

9. The flow detector of claim 8, wherein the first cylindric section defines a first planar surface and the second cylindric surface defines a second surface substantially parallel to the first surface, and wherein the first body, the second body, and the conduit wall are configured to cause the fluid flow to flow between the first surface and the second surface when the fluid flows through the flow path.

10. The flow detector of claim 8 or claim 9, wherein the first cylindric section is a first section of a particular cylinder and the second cylindric section is a second section of the particular cylinder.

11. The flow detector of any of claims 8-10, wherein the first cylindric section defines the first cross-sectional dimension in a first direction and the second cylindric section defines the second cross-sectional dimension in the first direction, and the first cross-sectional dimension, the second cross-sectional dimension, and a displacement between the first body and the second body define a linear dimension LD measured in the first direction.

12. The flow detector of claim 11, wherein the displacement between the first body and the second body is at least 20% of the conduit cross-sectional dimension.

13. The flow detector of claim 11 or claim 12, wherein the displacement between the first body and the second body is at least 30% of the linear dimension LD.

14. A method comprising: receiving, by processing circuitry, a signal indicative of movement of a fluidDocket No : A0009202 PCTO 1 / 1246-061 WOO 1 flow from a sensor, wherein the movement is caused when the fluid flows around a first body and around a second body within a flow path defined by a conduit, wherein the fluid flow has a Reynolds number less than or equal to about 9000 within the conduit, and wherein the sensor senses the movement at a location downstream of a stagnation feature of the second body, the stagnation feature configured to cause a stagnation point in the fluid flow when the fluid flows around the second body; determining, by the processing circuitry, a frequency of the movement; and determining, by the processing circuitry, a flow rate of the fluid flow within the flow path based on the frequency.

15. The method of claim 14, wherein the fluid flow has a Strouhal number less than or equal to about 0.3 within the conduit.

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