System for milk flow measurement and analysis

Abstract

Systems that improve the accuracy of measurement using differential pressure measurements, of the flow rate of milk from a nursing mother to an infant, by taking into account the presence of air bubbles, which often accompany the milk flow itself. In addition to the flow rate measurement, the systems are also able to provide a real-time analysis of the viscosity of the mother's supplied milk, the viscosity being a good measure of the fat content of the milk, which reflects the nutrient and calorific content of the milk. In addition, methods and systems are described for maintaining the calibration accuracy of the differential pressure measurements, by comparing their results with those of measurements made using the transit time of air bubbles in the milk flow. Systems for displaying the results on a remote computer or smartphone, and for sending to a database in the cloud, are also described.

Description

[0001] SYSTEM FOR MILK FLOW MEASUREMENT AND ANALYSIS

[0002] FIELD

[0003] The present disclosure describes technology related to the field of the measurement of the flow rate of the supply of milk from a nursing mother to an infant, and of performing specific analyses of that milk, including situations where there may be the presence of air bubbles in the milk flow.

[0004] BACKGROUND

[0005] There exist a large number of different systems and methods for quantitative determination of the flow rate of milk, from a nursing mother to an infant imbibing the milk supply. Some such systems and methods are described in the Background section of International Patent Publication WO 2023 / 194997 for "'System for Electronic Measurement of Milk Imbibed by an Infant”, commonly owned by the present applicant. The novel and inventive systems and methods which are the subject of that application involve a nipple device in which measurements are performed in real time on the milk flow, by conveying the flowing milk to a measurement head attached to a remote rim of the nipple device, the head then measuring the differential pressure generated by the milk flow as it traverses a hydraulic resistor. The compactness of the nipple device is therefore maintained. In the US published Patent Application 2020 / 0060217, for “Milking System” to G. Mostert et al, there is described a system for milking dairy animals, which includes a plurality of optical sensor elements, at least one light source, and a control unit which is configured to process sensor signals into values of at least two parameters of the milk in a measuring chamber. Detection and / or distinguishing between particles, in particular flakes or air bubbles in the milk, is performed by evaluating a wavelength, position and / or time dependency of the sensor signals from the plurality of sensor elements. Flakes may indicate mastitis in the animal, and such milk may need io be separated from milk intended for human consumption. This separation is not necessary if an air bubble is measured.

[0006] The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety. SUMMARY

[0007] The present disclosure attempts to provide novel systems and methods that improve the accuracy and usefulness of prior art systems and methods which use the measurement of the differential pressure generated by the milk flow through a hydraulic resistor, in order to determine the flow rate of the supply of milk from a nursing mother to an infant. The present disclosure describes exemplary systems and methods for a more accurate measurement by taking into account the presence of air bubbles, which almost inevitably accompany the milk flow itself. In addition to the flow rate measurement, the presently described systems are able to provide a real-time analysis of the viscosity of the mother’s supplied milk, the viscosity being a good measure of the fat content of the milk. The fat content is a prime gauge of the nutrient and calorific content of the milk, and therefore of importance not only for its nourishment value, but also for the peace of mind of the nursing mother. In addition, methods and systems are described for maintaining the calibration accuracy of the differential pressure measurements, by comparing their results with those of measurements made using sensors for detecting the presence of air bubbles, as described in this application.

[0008] Air bubbles are almost always present in the flow of milk from the mother to the infant, generally because of the way in which the infant sucks intermittently on the nipple. As the infant stops sucking momentarily, the negative pressure within the space between the inner surface of the nipple device and the mother’s breast, inputs air from the now non-sucking mouth of the infant, and this air can then enter the milk path, and can travel the whole length of the milk path when the infant begins to suck again. This presence of air bubbles in the milk flowing from the mother to the infant, can affect the ability of the system to perform an accurate measurement of the milk flow, which is performed by measuring the differential pressure across the hydraulic resistor through which the milk flows. Such air bubbles would cause a temporary change in the differential pressure measured as they pass through the hydraulic resistor, effectively causing the differential pressure to either drop as the bubble of air passes therethrough, if the air bubble is large and takes up all of the length of the resistor, or to show a sharp spike, if the air bubble is small, as will be explained in the Detailed Description section.. Therefore a method is required in order to determine when such air bubbles are passing through the differential pressure measurement device, so that the measurements in that period of time, are excluded from use in providing a measurement of the flow rate. It is to be understood that the term “air bubble” is used to indicate a section of the flow where the milk has been displaced by air, such that the “bubble” could take a comparatively long period of a number of seconds or even more to pass, during which time, the nursing session is still in progress, but the flow past the measurement components is composed of an air space, between sections of the milk flow. Alternatively, the bubble could be small such that its transit time is short, but with a similar need to be removed from the differential pressure data used by the device.

[0009] In the present disclosure, air bubbles are detected by their effect on the optical transmission of the fluid passing down the passageway, since when air replaces the milk flow, the optical transmission increases, since the absorption by the milk is not present. In examples of the presently described devices, this is achieved using an optical source on one side of the passageway, and a photodetector on the opposite side of the passageway. The photodetector can be any component whose output provides a measure of the light intensity falling on it. Examples of such detector components, could be a photovoltaic cell, or a photoresistor. When an air bubble is detected, the system controller rejects the differential pressure measurement data for the period during which the air bubble is detected, such that the flow rate is determined using only data obtained when milk is passing through the hydraulic resistor.

[0010] Since the differential pressure measurement across the hydraulic resistor is the basis for the measurement of the flow rate of the milk, it would be convenient to be able to use only the pressure measurement in order to detect when air bubbles are passing through the measurement head. This would obviate the need for optical air bubble sensors, and could simplify the devices. Measurements performed to compare the detection of air bubbles optically and a close inspection of the changes in the differential pressure measured, show that a correlation can be obtained between the shape deviations which show the passage of an air bubble in the optical measurement, and similar changes in the differential pressure measured across the hydraulic resistor. This shows that the differential pressure measurement can be used in order to detect passage of air bubbles through the hydraulic resistor, without the need of an optical air bubble sensor.

[0011] A further aspect of the devices of the present disclosure is the ability to measure the viscosity of the milk flowing through the passageways from the mother to the infant. This is achieved by using two hydraulic resistors having different cross sections, such that the velocity of the milk through the two resistors is different. The two resistors are arranged serially along the passageway in the measuring head, such that the milk flow rate through each of them is identical. Since the differential pressure generated by a viscous fluid flowing through a hydraulic resistor is proportional to the viscosity of the fluid and the flow rate of the fluid through the resistor, and decreases as the cross section of the resistor passageway increases, this enables the viscosity to be determined. Since the flow rate cannot be determined conveniently, the use of two serially connected resistors, each having a different cross section, enables the viscosity to be determined without the need to know what the flow rate is. The details of how this is calculated are given in the detailed description section hereinbelow. Since the fat content of the milk is probably the major element affecting its viscosity, a knowledge of the viscosity can provide information about the fat content of the milk.

[0012] Although, as mentioned hereinabove, the differential pressure measurements can be used to detect the passage of air bubbles, which is necessary only in order to preclude from the calculation of the milk flow rate, pressure measurements performed during the passage of air bubbles, there is a further use of the optical air bubble sensors, in performing accuracy checks of the differential pressure measurement of the milk flow rate. This application is based on the assumption that the accuracy of time measurements of the presence of an air bubble passing through the optical air bubble sensor, is maintained to a higher level than the accuracy by which the differential pressure measurements are used to measure the milk flow rate. Components for pressure measurements are more prone to drift than are time measurements .Therefore, the optical detection of the moment in time of the passage of an air bubble in the milk flow can be used in order to check the calibration of the differential pressure measurements to measure the milk flow rate. This can be performed by use of two optical air bubble sensors spaced apart by a predetermined length along one of the milk passageways, which can be used in order to determine the velocity of the milk flow to a good degree of accuracy. If the volume of milk between those two optical sensors is known, either by measurement of the dimensions of the section of passageway between the sensors, or by practical measurement amount of milk delivered in a known time, the flow rate can be determined just from the time data provided by the optical air bubble sensors. Because of the good level of accuracy of time measurements, this measurement of the milk flow rate too has a good level of accuracy, and is not as prone to changes in accuracy, as are the pressure measurements used in calculating the milk flow rate therefrom. Therefore, the use of a pair of optical air bubbles sensors can be used as a regular calibration device in order to correct any drift in the differential pressure flow rate measurement. Although the nipple devices of the present application are described and claimed as being intended for conveying and measuring milk from a mother’s breast to a nursing infant, it is to be understood that the devices are equally useful for conveying and measuring milk from the breast of a woman who is not the mother of the nursing infant. The reference to a mother is only used since that is the most common situation met with in nursing an infant, but it must be understood that the claims are intended to equally well cover situations when the milk provider is not the mother of the nursing infant.

[0013] To summarize the novelty and inventiveness of the devices and methods of the present disclosure, in one exemplary embodiment, the present subject disclosure includes a nipple device provided to measure a milk flow rate from a breast of a mother to a nursing infant. The nipple device includes a first passageway to convey milk from the breast of the mother to a remote location from an inside surface of a domed sucking protrusion of the nipple device. A second passageway is provided to convey the milk back from the remote location to at least one exit orifice in an outer surface of the domed sucking protrusion from which the nursing infant will feed. A hydraulic resistor is provided in a path between the first and second passageways through which the milk flows from the mother to the nursing infant. A first pressure sensor and a second pressure sensor are disposed relative to ends of the hydraulic resistor. A controller detects a differential pressure across the hydraulic resistor to provide a measure of the milk flow rate from the mother to the nursing infant. The novel feature of the presently described device is that an optical sensor is adapted to measure an optical transmission across at least one of the passageways, such that the presence of at least one air bubble passing through the passageway is detected by the optical sensor.

[0014] In another exemplary embodiment, the present subject disclosure includes a nipple device for determining a viscosity of a milk flow from a mother to a nursing infant. The nipple device includes passageways to convey milk from a breast of the mother to the nursing infant. A first hydraulic resistor and a second hydraulic resistor are disposed serially in either order along the passageways, so that the milk flows serially through both of the hydraulic resistors. The first hydraulic resistor has a smaller flow cross sectional area than the second hydraulic resistor. The milk flows at a higher velocity through the first hydraulic resistor that has the smaller flow cross sectional area than the milk flow velocity through the second hydraulic resistor. Pressure sensors are provided to measure the differential pressure of the milk flow across the first hydraulic resistor and across the second hydraulic resistor. A control system is adapted to detect the difference in differential pressures measured across the first hydraulic resistor and across the second hydraulic resistor in order to calculate the viscosity of the milk flowing serially through the hydraulic resistors.

[0015] In another exemplary embodiment, the present subject disclosure includes a self-calibrating nipple device provided to measure a milk flow rate from a mother to a nursing infant. The self-calibrating nipple device includes an arrangement of passageways that convey milk from a breast of the mother to the nursing infant. A hydraulic resistor is disposed along the passageways such that the milk flows through the hydraulic resistor in its path from the mother to the nursing infant. Pressure sensors are provided to measure the differential pressure of the milk flow across ends of the hydraulic resistor to determine the milk flow rate. A pair of optical air bubble sensors are disposed at a predetermined distance apart along the passageways. A control system is adapted to determine the milk flow rate from the transit time of an air bubble presence between the pair of optical air bubble sensors. Based on the detected milk flow rate, the control system can correct a measurement of the milk flow rate determined by the differential pressure measurement according to the milk flow rate determined by the transit time of an air bubble presence between the pair of optical air bubble sensors.

[0016] There is thus provided in accordance with an exemplary implementation of the devices described in this disclosure, a nipple device to measure a milk flow from a breast of a mother to a nursing infant, the nipple device comprising:

[0017] (i) a first passageway, opening onto an inside surface of a domed sucking protrusion of the nipple device, to convey milk from the breast of the mother to a location remote from the domed sucking protrusion, and a second passageway to convey the milk back from the remote location to at least one exit orifice in an outer surface of the domed sucking protrusion, from which the nursing infant feeds;

[0018] (ii) a hydraulic resistor in a path between the first and second passageways, through which the milk from the mother to the nursing infant flows;

[0019] (iii) a first pressure sensor and a second pressure sensor disposed relative to ends of the hydraulic resistor, such that a controller detects a differential pressure across the hydraulic resistor to provide a measure of the milk flow rate from the mother to the nursing infant, and an optical sensor adapted to measure an optical transmission across at least one of the passageways, such that the presence of at least one air bubble passing through the at least one passageway is detected by the optical sensor, wherein the controller may be adapted to reject from the differential pressure data used to determine the milk flow rate, that data which is obtained during the duration of the presence of air bubbles in the milk flow.

[0020] The optical sensor may comprise a light source on one side of a passageway, and a light detector on an opposite side, and the light detector can be either a photovoltaic detector or a photoresistor.

[0021] In any of these nipple devices, the controller may identify the presence of an air bubble by detecting a change of more than a predetermined level occurring during less than a predetermined time, in the optical transmission measured by the optical sensor. Additionally, the detection of air bubbles in the milk flow enables the accuracy of the milk flow rate to be improved over that of devices which do not take into account the presence of air bubbles in the milk flow.

[0022] There is further provided, according to another exemplary implementation of the devices of the present application, a nipple device to determine the viscosity of a milk flow from a mother to a nursing infant, the nipple device comprising:

[0023] (i) passageways to convey milk from a breast of the mother to the nursing infant;

[0024] (ii) a first hydraulic resistor and a second hydraulic resistor disposed serially in either order along the passageways, such that the milk flows serially through both of the hydraulic resistors, the first hydraulic resistor having a smaller cross sectional area than the second hydraulic resistor, such that the milk flows at a higher velocity through the first hydraulic resistor having the smaller flow cross sectional area than the milk velocity through the second hydraulic resistor having a larger cross sectional area;

[0025] (iii) pressure sensors to measure the differential pressure of the milk flow across the first hydraulic resistor and across the second hydraulic resistor; and

[0026] (iv) a control system adapted to determine the difference in differential pressures measured across the first hydraulic resistor and across the second hydraulic resistor, in order to calculate the viscosity of the milk flowing serially through the hydraulic resistors.

[0027] In such a nipple device, the first hydraulic resistor having the smaller flow cross sectional area may be a tube or an orifice having a smaller cross sectional area than that of the second hydraulic resistor. In any of these nipple device, the hydraulic resistors may be tubular in shape, and the control system is adapted to base the calculation of the viscosity of the milk on the relationship that the flow rate of the milk through a tubular hydraulic resistor is given by the expression: where:

[0028] Q is the flow rate of the milk,

[0029] ΔP is the pressure differential across the ends of the tubular hydraulic resistor, r is the effective radius of the tubular hydraulic resistor, p is the viscosity of the milk, and

[0030] L is the effective length of the tubular hydraulic resistor, and wherein use of an equal flow rate of the milk through the first and the second hydraulic resistors enables the viscosity of the milk to be determined.

[0031] In such a case, the control system may determine the viscosity of the milk without prior knowledge of the effective radius and effective length of the two resistors, by use of previously performed calibration measurements made at a number of different flow rates.

[0032] An even further exemplary implementation of the devices of the present application, describes a self-calibrating nipple device to measure milk flow rate from a mother to a nursing infant, the self-calibrating nipple device comprising:

[0033] (i) an arrangement of passageways to convey milk from a breast of the mother to the nursing infant;

[0034] (ii) a hydraulic resistor disposed along the passageways such that the milk flows through the hydraulic resistor in its path from the mother to the nursing infant;

[0035] (iii) pressure sensors to measure the differential pressure of the milk flow across ends of the hydraulic resistor to determine the milk flow rate;

[0036] (iv) a pair of optical air bubble sensors disposed at a predetermined distance apart along the passageways; and

[0037] (v) a control system adapted to determine the milk flow rate from the transit time of an air bubble feature between the pair of optical air bubble sensors, and to correct a measurement of the milk flow rate determined by the differential pressure measurement according to the milk flow rate determined by the transit time of an air bubble feature between the pair of optical air bubble sensors. In such a self-calibrating nipple device, the air bubble feature enables a point in time of the passage of the air bubble to be determined, for an air bubble having a passage time longer than a predetermined minimum. The control system is then adapted to perform a calibration by:

[0038] (i) measuring the transit time of an air bubble feature between the pair of optical air bubble sensors disposed at a predetermined distance apart,

[0039] (ii) determining the velocity of the milk flow, and

[0040] (iii) further calculating the milk flow rate from a knowledge of the effective cross-section of the passageway between the pair of optical air bubble sensors, such that the calculated milk flow rate can be used to determine the accuracy of the milk flow rate obtained from the differential pressure measurement of the milk flow.

[0041] The velocity of the milk flow is known from a knowledge of the effective distance apart of the pair of optical air bubble sensors, and of the measured transit time of an air bubble feature between the pair of optical air bubble sensors. The effective distance apart of the pair of optical air bubble sensors may be determined either by measurement along the passageway, or by using a calibration procedure by measuring the amount of milk or alternative fluid passed in a predetermined time period.

[0042] In any of these self-calibrating nipple devices, the control system may be adapted to monitor the optical air bubble sensors at predetermined intervals, and to perform calibrations of the differential pressure measurement of the milk flow rate, from the milk flow rate determined by the air bubble feature transit time between the optical air bubble sensors.

[0043] In any of the nipple devices described hereinabove, the pressure data from the pressure sensors may be transmitted by a wired connection or wirelessly to a remote computing device, where calculations are performed in order to provide at least one of the milk flow rate or the milk viscosity. The milk flow rate or the milk viscosity can then be displayed on a screen of the remote computing device. They can further be sent wirelessly to a remote database for storage. The data regarding at least one of the milk flow rate, or the milk viscosity can be sent to a remote computing device for at least one of display or storage or transmitting to a remote database. The remote computing device may be a smartphone. Finally, there is further provided according to yet another implementation of the devices of the present application, a nipple device to measure a milk flow from a breast of a mother to a nursing infant, the nipple device comprising:

[0044] (i) a first passageway, opening onto an inside surface of a domed sucking protrusion of the nipple device, to convey milk from the breast of the mother to a location remote from the domed sucking protrusion, and a second passageway to convey the milk back from the remote location to at least one exit orifice in an outer surface of the domed sucking protrusion, from which the nursing infant feeds;

[0045] (ii) a hydraulic resistor in a path between the first and second passageways, through which the milk from the mother to the nursing infant flows; and

[0046] (iii) a first pressure sensor and a second pressure sensor disposed relative to ends of the hydraulic resistor, such that a controller detects a differential pressure across the hydraulic resistor to provide a measure of the milk flow rate from the mother to the nursing infant, wherein the presence of an air bubble in the milk flow can be identified by detecting a change of more than a predetermined level in the differential pressure measured across the hydraulic resistor, the change occurring during less than a predetermined time.

[0047] In such a nipple device, the controller may be adapted to reject from differential pressure data used to determine the milk flow rate, that data which is obtained during the duration of the presence of an air bubble in the milk flow.

[0048] BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

[0050] Fig. 1 A is an exploded view of a nipple device for measuring a milk flow from a mother to a nursing infant;

[0051] Fig. IB is a assembled perspective view of the nipple device of Fig. 1A;

[0052] Fig. 1C shows a plan schematic view of internal parts of the nipple device of Figs. ! 1A and IB, for measurement of the milk imbibed by an infant;

[0053] Fig. 2 illustrates schematically how the implementations shown in Fig. 1C can be adapted to show the passage of air bubbles, by use of an optical sensor system;

[0054] Fig. 3 shows an exemplary isometric view of how the optical air sensor module can be advantageously incorporated into the device of the present application; Fig. 4 is a graph of the transmitted light level of the optical sensor as milk passes it, showing an exemplary plot of air bubbles intermittent to the milk flow;

[0055] Fig. 5 shows three graphs illustrating the presence of air bubbles in the milk flow of a nursing session, the graphs being used to illustrate methods according to the present and how to handle and how to utilize such air bubbles in measurement of the milk flow;

[0056] Fig. 6A provides information relating to the variation of the flow rate as a function of the differential pressure, according to the viscosity of various fluids being measured, thereby explaining the methods enabling the determination of fat content analysis of the milk;

[0057] Figs. 6B provides information relating to the variation of the flow rate as a function of the differential pressure across different types of hydraulic resistors, as a function of flow rate through the resistors;

[0058] Fig. 7A illustrates a first hydraulic resistor arrangement having a long tubular structure;

[0059] Fig. 7B depicts a hydraulic resistor arrangement of the nipple device, having a short and narrow passageway with a higher flow velocity than that illustrated in Fig. 7A;

[0060] Fig. 7C depicts a hydraulic resistor arrangement in which three pressure measurements are taken in order to enable measurement of the viscosity of the milk;

[0061] Fig. 8 illustrates an example adaption to the device of Fig. 2, to enable the measurement of the viscosity of the milk to be determined, from which the fat content of the milk can be obtained;

[0062] Fig. 9 illustrates an exemplary system and method of how a calibration procedure can be provided for the devices of the present application, using additional optical air bubble sensors;

[0063] Fig. 10A shows a first location for a pair of optical air bubble sensors along a milk channel;

[0064] Fig. 10B illustrates a second location for a pair of optical air bubble sensors disposed along a milk channel relative to a hydraulic resistor;

[0065] Fig. IOC depicts another configuration for a hydraulic resistor relative to a pair of pressure sensors; and

[0066] Fig. 11 illustrates schematically how the nipple devices described in the previous drawings can be used with a remote computer device or a smartphone, on which the calculations of the milk flow rate or the milk viscosity to provide its fat content, can be performed and displayed, or enabling sending of the measurements to a database in the cloud. DETAILED DESCRIPTION

[0067] Reference is now made to Figs. 1A, IB and 1C, which illustrate schematically different views of a milk flow rate measurement device, such as that described in International Patent Publication WO 2023 / 194997 for “System for Electronic Measurement of Milk Imbibed by an Infant”, commonly owned by the present applicant the entirety of which is incorporated by reference. Fig. 1.A shows an isometric view of an example of such a system in a disassembled situation, showing the main parts, while Fig. IB shows the device completely assembled. Fig. IC illustrates a schematic view of the internal milk flow passageways, and the location of the hydraulic resistor and of the pressure sensors in die electronic measurement unit, which controls the entire measurement. The device 100 comprises three separate parts, firstly the nipple part 10 for positioning on the mother’s breast and on which the infant sucks to imbibe the mother’s milk, secondly, a hydraulic or fluid resistor 11 unit inserted into the base 12 of the nipple part, and lastly, an electronic measurement head 13 including a controller 14 (shown in Fig. IC) for calculating the milk flow rate from a measurement of the pressure drop of die milk flowing through die hydraulic resistor.

[0068] That differential pressure measurement is performed by two pressure sensors 15 located in die electronic measurement head at opposite ends of die hydraulic resistor 11. The flow of milk itself is channeled by means of a pair of passageways, one passageway 16 flowing from the inside surface of the nipple unit, from where it conveys die mother’s milk to one end of the hydraulic resistor 11, and the other passageway 17 leading back from the other end of die hydraulic resistor, to openings on die outer surface of the nipple, from which the infant sucks the milk. The pressure drop across the hydraulic resistor is therefore directly proportional to the rate of flow of the milk. 'Fhe controller 14 then converts the differential pressure measurement into a measure of the flow of the milk to the infant. As an alternative to calculation of die milk flow rate by die device controller 14, die pressure measurement data can be transmitted by a short range wireless communication link 18 to a nearby computer or smart phone, which can process the data on a dedicated application, or send it to a remote database for processing or adding to the database. Further details of the hydraulic resistor and of the nipple device structure, and of the electronic measurement configuration are given in die above -mentioned WO 2023 / 194997, herewith incorporated by reference. As explained in the Summary Section above, the presence of air bubbles in the milk flowing from the mother to the infant, can affect the accuracy, or even the ability, to perform an accurate measurement of the milk flow, using the differential pressure across the hydraulic resistor. Such air bubbles would cause a change in the differential pressure measured as they pass through the hydraulic resistor, effectively causing the differential pressure to drop momentarily if the air bubble is large, since a resistor tube containing at least partly air, will not support such a large pressure drop as a milk-filled tube. As will be explained further in connection with Fig. 5 below, if the air bubble is small, the differential pressure shows a sharp spike-shaped increase, before settling back to its trending level. Both of these types of air bubbles are therefore detrimental to the measurement of the differential pressure. Therefore a method is required in order to determine when such air bubbles are passing through the measurement device, so that the pressures measured in that period of time, are excluded from the measurement of the flow rate. Otherwise, the controller will consider the air bubble passage as a milk flow, which will lead to an error in the milk flow calculation.

[0069] Reference is now made to Fig. 2, which illustrates schematically how the implementations shown in Fig. 1C can be adapted to show the passage of air bubbles, in order to avoid such air bubbles from interfering with an accurate measurement of the milk flow rate. In Fig. 2, the parts of the milk flow measurement device 100 are labelled sequentially- (i) base nipple 10, (ii) hydraulic resistor 11, (iii) pressure sensors 15 and (iv) controller 14, the controller 14 being capable of sending via the communication link 18, the measured pressure data to a remote smartphone or computer, as shown hereinbelow in Fig. 11, where an application can process the data, store it or send it to a database in the cloud. The system shown in Fig. 2 differs from the previously shown measurement device of Figs. 1C, in that immediately before or after the hydraulic resistor 11, an optical sensor 20 is fitted across the flow path, the sensor 20 being capable of detecting when an air bubble passes, by the increase in optical transmission across the flow path. The optical air bubble sensor 20 measures the optical transmission of light across the passageway flow path, using an optical emitter 21 on one side of the passageway and a light detector 22 on the opposite side. Because of the schematic nature of Fig. 2, although the light emitter 21 and the light detector 22 are shown, for simplicity, in the plane of the nipple device base, i.e. in the plane of the drawing, it is to be understood that in practice, it may be more practical to position the light emitter and detector perpendicular to the plane of the nipple device base. The level of light detected by the detector 22 indicates when air is passing the milk passageway at the position of the optical sensor 20, since when air is present in the passageway, the optical transmission is substantially higher than when milk is present in the passageway. The output of the detector 22 can be input to the device controller 14, providing information as to the periods in time when an air bubble is passing. Instructions can thus be input to the milk flow calculation algorithm running on the controller 14, to exclude from the data used for determining the milk flow rate, those periods of time when an air bubble is passing, and to thereby calculate the milk flow with better and more reliable accuracy. The light source 21 can be conveniently implemented by the use of a light emitting diode (LED), which can be powered from a source in the controller 14, and the light detector 22 can be conveniently implemented by the use of a photodiode or a photoresistor. However, it is to be understood that these options are merely convenient components to use, and are not intended to be limiting. As an alternative to calculation of the milk flow rate by the device controller 14, the pressure measurement data can be transmitted by a short range wireless communication link 18 to a nearby computer or smart phone, which can process the data on a dedicated application, in order to subtract any periods of time when air bubbles are passing. The milk flow information thereby obtained can also be transmitted to a database in the cloud, where it can be used to track the mother’s milk production, or the infant’s milk intake, or to compare with previous feeding session, or with stored more universal data.

[0070] Reference is now made to Fig. 3, which is an isometric view of a complete measurement device 100 (slightly separated for clarity), with the optical air sensor unit 20 incorporated into the device as a measurement unit disposed between flow connection ports of the base nipple 10 and the hydraulic resistor unit 11, the control and communication unit 13 being attached distally to the hydraulic resistor unit. All of the electronic measurement parts are thus remotely located from the nipple protrusion 30, from where the infant sucks the milk. However, it is to be understood that the positions and forms of the component parts of the complete measurement device may be different from those shown in Figs. 1A, IB and 3, without detracting from the inventive nature of the device and its functionality. Thus, for instance, while in the devices shown in those drawings, the hydraulic resistor is mounted in the base section 10 of the nipple, it could also be designed to be mounted in the electronic differential pressure measurement head 13, or even as a part of the electronic measurement head, in which case, its sterilization will need to be performed by flowing the sterilizing solution through the device. Reference is now made to Fig. 4, which illustrates a sample graph of the transmitted light level of the optical sensor, over a period of time (slightly more than 15 minutes in the example shown) to show the typical, but not limiting, extent and frequency of periods of air bubble passage during the milk flow. The abscissa of the graph shows the elapsed time in seconds, while the ordinate shows a measure of the inverse of the level of transmitted light detected at the optical sensor. The optical detector used in this exemplary device, from which the data of the graph was taken, is a photoresistor, and the ordinate scale shows the resistance of the photoresistor. The characteristics of the photoresistor are such that the resistance moves inversely to the light intensity falling thereon, i.e. the higher the light intensity, the lower the resistance, and vice versa. Consequently, as the level of light detected decreases, the resistance increases. Therefore, in the graph of Fig. 4, the higher positions on the ordinate scale, i.e. the higher measured resistance, represent lower levels of detected light. When an air bubble passes the optical sensor unit, the transmitted light is higher than when milk is passing the sensor unit, so that the resistance measured is lower than when milk is passing, as indicated by the lower bounds of the light level plot. When milk is passing through the sensor unit, the transmitted light level is lower than for air passage because of the absorption of the light by the milk, and the resistance measured is consequently higher, as indicated by the higher bounds of the resistance plot.

[0071] As is observed in Fig. 4, the nursing sequence shown commenced with a period 40 of only air passing the optical sensor, since even after the infant has begun sucking, the milk may reach the optical sensor location only after a number of seconds, both because of the time taken for the leading part of the milk flow to physically reach the sensor, but also because of physiological effects which may occur in the mother’ s breast when the infant begins to suck. Once the milk began flowing, it could contain air bubbles at any point of time, depending on the infant’s breathing and sucking actions, and on the latching efficiency, i.e. air tightness, of the nipple to the mother’s breast. There may also be periods of a number of seconds in which the infant takes a pause from his / her sucking, at which a long bubble of air might be detected, such as is shown in the trace of Fig. 4, stretching from approximately 237 secs, to 253 secs, on the time axis, and marked 41 on the graph. As the nursing session proceeded, it is seen from the example trace of Fig. 4, that the occurrence of air bubbles became lower as the milk flow became steadier, until the flow was almost entirely of milk, from approximately the 900 sec. mark, until the end of the session at approximately 1025 secs., marked 42 on the graph. As stated hereinabove, those periods of time when an air bubble is passing, are excluded by the flow determination algorithm, from the data used for determining the milk flow rate, in order to ensure a more accurate milk flow rate measurement, as determined in the control unit 14 from the differential pressure measurement performed across the hydraulic resistor 11. Since the measurement method used for milk flow rate determination is based on the differential pressure measurements performed across the hydraulic resistor, it would be useful, both from the point of view of the manufacturing cost of the device, and from its complexity and compactness, to determine whether it is possible to detect the presence of air bubbles directly from the differential pressure measurements, without the need for the optical sensor unit 20.

[0072] Reference is now made to Fig. 5, which shows three graphs of a nursing session, the top graph, marked 5A, being a section of the graph of Fig. 4, showing one region 50 in which the flow was essentially of milk only, without any significant air bubbles, and a second region 51 in which the milk flow contained a large number of small air bubbles. The limiting bounds of the milk-only passage, and of air-only passage are marked accordingly. Graphs 5B and 5C, are magnified time scale plots, this time of the measured differential pressure AP across the hydraulic resistor, corresponding respectively to the two above-mentioned regions of graph 5A, which shows, as in Fig. 4, the light transmission through the optical sensor. The timescale of graphs 5B and 5C are such that individual sucking actions of the infant, occurring at a rate of slightly less than a second per sucking action, can be seen with high temporal resolution in the graphs. Graph 5B shows a reasonably smooth profile of the differential pressure change during each sucking action, as expected from a clear flow of milk without a significant level of air bubbles. This is typical of the infant sucking efficiently on the nipple, with a steady sucking action, and a steady flow of milk. Graph 5C on the other hand, plotted during a period of time on the graph 5A, when there was a significant concentration of air bubbles, shows a very different profile to that of graph 5B, with small sharp spikes in the differential pressure plots occurring at random temporal positions of the plot. These spikes are interpreted as being rapid incremental changes in the measured differential pressure at the moments in time when small air bubbles pass through the hydraulic resistor. Such small air bubbles arise typically when the infant is tiring or has less inclination or strength to suck strongly. This situation can also occur during normal breastfeeding, when milk moves back and forth in the nipple due to changes in pressure during a normal breastfeeding cycle. As is seen Fig. 5C, for instance at the points where “air bubbles” is marked on the graph plot of the measured differential pressure, these spikes show a small but sharp rise followed by a sharp fall, before the differential pressure curve reverts to its trending path. It is believed that the shape of these spikes may be due to the passage of small bubbles whose size is of a similar order as the length of the hydraulic resistor. The shape of these spikes is thought to be an outcome of the physical surface tension properties of the milk / air interface at the bubble surface. The mechanism is based on the understanding that the surface tension of an air bubble causes resistance to a change in the shape of the surface of the bubble, generating the same effect as a partial blockage. Thus when the air bubble passing through the system reaches the hydraulic resistor, and is forced to enter the narrower bore of the hydraulic resistor by the flow of milk behind it, the additional resistance of the bubble surface to enter the narrower bore of the hydraulic resistor, causes the differential pressure measured across the resistor to rise sharply. Then, once at least the front surface of the air bubble has entered the narrower bore of the hydraulic resistor and begins to advance within the resistor, the differential pressure falls sharply back to its original position in the curve, with an overshoot. Likewise, when the small bubble reaches the outer end of the resistor and its trailing surface leaves the resistor bore, the differential pressure may again show a sharp rise and fall back to its original position, with an overshoot. This behavior of the differential pressure as a bubble is passing through the resistor is counterintuitive to what would be expected by a longer air bubble. In that case, both pressure sensors are located in the air pocket of the longer air bubble, and since the air cannot support essentially any pressure, the differential pressure reading falls almost to zero. This is what is shown in the graph of Fig. 4 in the region marked 41, where a long bubble of air might be detected.

[0073] A characterization of the shape, height and duration of these differential pressure spikes, enables the system algorithm to determine which shape deviations of the plot represent real air bubbles, and their duration, and which shape deviations are merely small and random noise, similar to those shown in graph 5B, where essentially no air bubbles were passed. Thus, a change in the differential pressure reading of more than a predetermined level occurring over less than a predetermined time period, can thus be determined as being likely due to an air bubble, and the control system is then able to exclude such time segments containing such bubbles from the calculation of the milk flow rate obtained from other regions of the graphs, which are assumed to have a minimal level of air bubbles, insufficient to disturb an accurate reading of the milk flow rate. Typical results, displayed in Fig. 5, thus show that it should be possible to detect air bubbles using only the differential pressure measurements across the hydraulic resistor 11, thereby obviating the need for optical air bubble sensors, at least for the purpose of ensuring that air bubbles do not interfere with the accuracy of the milk flow rate measurement.

[0074] However, it is to be emphasized that whether related to an optical sensor based comparison measurement, or to a flow measurement based solely on the differential pressure measurement, since there are so many variables which affect the nature of the passage of air bubbles down the hydraulic resistor, it is difficult to give specific quantitative values to the extent of change in differential pressure measured, and the time duration of the passage of the air bubble through the resistor. Thus, for instance, an important factor which affects the AP and passage time levels is the physical dimensions and the form of the hydraulic resistor, the higher the resistance, the larger the AP change. Other factors affecting the anomaly levels and time duration of the bubble passage are the size of the bubble itself, the viscosity of the milk, the temperature of the milk, which of course has an effect on the viscosity, the milk flow rate, and the overall pressure difference measured, which itself too depends on the hydraulic resistor. However, once the hydraulic flow system design for the nipple device has been finalized, all of these factors can be characterized, even if only to a large range, and the person of skill in the art can determine what predetermined change in AP is to be anticipated for the range of bubbles expected, and the approximate predetermined time duration of the AP change, such that the limits to be used for determining when the differential pressure measurement may be unreliable, and hence not used, can be entered into the controller algorithm for obtaining reliable flow rate measurements.

[0075] For the example shown in graph 5C of Fig. 5, passage of a small air bubble through the hydraulic resistor used, results in a jump and dip from the mean differential pressure measured, of the order of 50mm. of mercury in each direction, and the sharp rise and fall anomaly lasts for a time of the order of 50 msec. However, it is to be emphasized that these numerical values may be only order-of-magnitude values, which could vary by 100% or even more in both directions, and therefore should not be taken as limiting.

[0076] Besides the above described use of the optical air bubble sensors to ensure accurate milk flow measurements, the optical transmission determination of the presently described devices also provides support for the determination of important parameters in the analysis of the milk provided by the mother, the most important parameter being the fat content of the milk. As is noted in the example graph of Fig. 4, as the feeding session proceeds, the measured resistance of the photoresistor shows a gradual rise, starting for the milk-only level at approximately 650Q, and finishing at 770 Ω. This means that the level of optical transmission through the milk was decreasing, which itself means that the milk was becoming less transmissive or more turbid. This increase in turbidity of the milk during the course of a nursing session may possibly be ascribed to an increase in the fat content of the milk. However, because of the complex nature of the optical transmissivity property of the milk, there being many possible components of the milk that could affect its light opacity, it is necessary to base a fat content determination on a property of the milk more specifically related to the fat content than just optical absorption.

[0077] In the presently described devices, it is proposed that the viscosity of the milk is a more specifically directed property indicating the fat content of the milk, the higher the fat content, the more viscous is the milk. The milk flow detection devices of the present disclosure are able to determine the viscosity of the milk, and thereby, provide an indication, in real time, of the fat content of the milk being provided by the mother to the infant.

[0078] Reference is now made to Figs. 6 A and 6B which provide background information for the milk viscosity measurement methods of the present disclosure, ultimately enabling a fat content analysis of the milk. In Fig. 6A, there is shown how the flow rate Q of different fluids through a hydraulic resistor are dependent on the viscosity of the fluid. As the differential pressure DP across the hydraulic resistor increases, the flow rate also increases, but that relationship is also a function of the viscosity of the liquid. These relationships are shown for cow’s milk with two different levels of fat content, 1% and 3%, and for water. As is observed, as the viscosity increases from that of water to that of the 3% milk, the differential pressure DP required to achieve a certain flow rate Q, also increases, as expected. The problem to be solved is therefore how to determine the viscosity from the three- dimensional relationship between viscosity, differential pressure and the milk flow rate.

[0079] Reference is now made to Fig. 6B, which shows, as in Fig. 6A, the relationship between the differential pressure across a hydraulic resistor as a function of the flow rate through the resistor, but this time for a fluid having a predefined viscosity, but passing through differently characterized hydraulic resistors. The exemplary fluid used in this graph is cow’s milk having a 3% fat content. Hydraulic resistor A has a larger cross section than that of hydraulic resistor B. For instance, resistor A could be in the form of a certain tubular passageway, while resistor B could be in the form of a tube, narrower than that of resistor A, or even a hole in a sheet of material, interposed in the milk flow passageway. Consequently, for the same milk flow rate, in order to pass the same quantity of milk per unit of time, the milk flow velocity through hydraulic resistor B must be higher than that for hydraulic resistor A. The milk flow velocity is an important characteristic in the presently described implementation of a milk analysis device, since flow velocity through a given hydraulic resistor can be used as a measure which allows comparison between fluids having different viscosities. By comparing the differential pressure resulting from the milk flow through passages having different restrictive effects on the milk flow, and hence generating different flow velocities and different levels of the laminarity of the milk flow, it is possible to determine the viscosity of the milk. Since the milk viscosity is directly related to the fat content of the milk, if the viscosity can be estimated, a measure of the fat content of milk can also be obtained. A method and component arrangement must therefore be devised in order to determine the viscosity of the milk.

[0080] In the devices of the present application, this determination of the viscosity is achieved by flowing the milk through two serially connected hydraulic resistors having different cross sections. Consequently, the two hydraulic resistors have different effects on the flow characteristics of the milk through each of the resistors, and particularly the flow velocity through each of the resistors. It should be noted in passing, that the different flow velocities generated by the two resistors does not imply that the resistors need to have different resistance values.

[0081] One of the resistors, which will be termed the first resistor A, as in Fig. 6B, has a larger cross-section than the other resistor, B, the cross-sectional area being such that for the flow rates used in the device, the flow maintains a good, low turbulent, laminar nature, as defined by the flow having a Reynolds number below a predetermined level, generally well below 2000. Such laminar flow has a lower velocity and lower turbulence than a flow less laminar in nature. The other resistor, which will be termed the second resistor B, has a smaller cross section than the first resistor, such that the flow velocity is higher, and the laminar nature of the flow is reduced compared with the flow in the first resistor. This difference in the nature of the flow between the first and second resistors, can be used to determine the milk viscosity. The same flow rate of the milk through hydraulic resistors A and B generates different differential pressures across each resistor, as is clear from the graphs of Figs. 6A and 6B. Therefore, the viscosity of the milk can be determined from the differences in differential pressure across the two different hydraulic resistors, A and B.

[0082] One way of illustrating how the viscosity of the milk could be measured, makes use of the physical law known as Poiseuille's law, which governs the rate of flow of a fluid through a passage. Poiseuille’s law can be applied to two differently characterized and dimensioned tubular resistors, which are also called A and B in this explanation. Poiseuille’s law states that: where:

[0083] Q is the flow rate of the fluid,

[0084] AP is the pressure differential across the ends of the tube, r is the effective radius of the tube, p is the viscosity of the fluid, and

[0085] L is the length of the tube.

[0086] Using the suffixes A and B for defining the variables related to the fluid resistor called A and the fluid resistor called B, the quantities QA and QB flowing through the resistors A and B respectively, are given by the expressions: and

[0087] If equations (2) and (3) can be solved, the viscosity p of the fluid flow can be determined. In equations (2) and (3), all of the elements are known, except for p which is the viscosity coefficient to be determined, and QA and QB, which cannot be readily measured in a device such as the milk flow nipple of the present disclosure. Therefore, the solution for p involves 3 unknowns, but only 2 equations, and it is impossible to analytically solve for three unknowns from only 2 equations.

[0088] This problem is solved in the presently described devices, by the novel notion of arranging the two resistors, A and B, in series, such that the milk flows from one through the other, providing equal flow through both of the resistors. Consequently: and by equating the right hand sides of equations (2) and (3), there is obtained that:

[0089] Since all of the elements in equation (5) other than p, are either known from the physical dimensions of the two resistors (rA, rB, LA, LB), or, in the case of ΔPA and ΔPB, are measured using pressure sensors, solution of equation (5) enables the viscosity coefficient p to be readily obtained.

[0090] Poisueille’s law is only strictly valid for laminar flow of the fluid through the passageway, and since the milk flow through the narrower fluid resistor B has a higher velocity, it therefore is less laminar and may even have a certain level of turbulence. Consequently, Poiseuille’s law is not accurately applicable, and the above described method of determining the viscosity coefficient of the milk should only be considered as providing an estimate of the viscosity, and not an exact measurement. The accuracy can be improved if preliminary calibration runs are performed, and the measurement algorithm applies a correction accordingly, for the possible lack of laminar flow. Alternatively and advantageously, if the hydraulic resistor cross sections are chosen such that even for the narrow cross section resistor B, the flow is still regarded as being in the laminar region, as determined for instance by being less than a predetermined Reynolds number, then Poisueille’s law can be considered to be obeyed sufficiency closely that the viscosity measurement may be considered to be sufficiently accurate.

[0091] In practice, the values of r and L do not need to be measured physically, but can be determined by performing calibration runs on the device, using different known flow rates and fluids having different known viscosities, and the results stored in the system memory for use by the controller algorithm for calculating the value of the viscosity coefficient jl. Once the viscosity coefficient is known, the controller can also provide an indication of the fat content of the milk.

[0092] Reference is now made to Figs. 7A to 7C, which illustrate schematically in three stages, how the hydraulic resistor arrangement of the above described devices, as shown in Figs. 2 and 3, can be further developed to enable the devices to measure the viscosity of the milk

[0093] In Fig, 7A, there is shown a single hydraulic resistor, as used in the previously described implementations, the resistor comprising a comparatively long tube 70 with good flow characteristics, and wherein the pressure drop through the tube is measured by pressure sensors P2 and P3. This hydraulic resistor is an implementation of what has been called hereinabove, resistor A.

[0094] In Fig. 7B, there is shown a second hydraulic resistor, equivalent to what has been called hereinabove resistor B, comprising a short and, more importantly, narrow passageway 71 generally having a higher flow constraint than that of the resistor of Fig. 7A, though flow constraint is not a main factor in the operation of this method of determining the viscosity of the milk. The important factor is that for the same flow rate of fluid through this resistor B as that of resistor A in Fig. 7 A, the flow speed in resistor B will be significantly higher, because of its smaller flow cross-section. This resistor could even be in the form of an orifice rather than a narrow tube. Nevertheless, in spite of the higher flow speed through resistor B, the flow cross-section is chosen, such that the flow through it is still in a range where the laminar flow is such that Poiseuille's law is still generally applicable. The pressure drop through this resistor is measured by pressure sensors Pl and P2.

[0095] Finally, in Fig. 7C, there is shown a schematic arrangement of the two resistors of Fig. 7A and Fig. 7B in series, such that the milk flows through both of them sequentially. This is the novel arrangement of the presently described device that ensures that the flow rate through both resistors is equal, even though the flow speed through resistor B is higher than that of resistor A. In this case, three pressure measurements have to be made, the measurement between Pl and P2 being the differential pressure APB across the higher velocity flow narrower resistor B, while the differential pressure APA across the lower velocity, higher laminar flow resistor A, is measured by pressure sensors P2 and P3. The entry passageway of the milk through this double resistor arrangement, is shown optionally with a significantly wider passage, in order to supply the milk to the double resistor array without any significant flow resistance.

[0096] As shown in the previously mentioned in International Patent Application WO 2022 / 175833, the provision of the hydraulic resistors on the outer surface of the resistor body, has advantages in that the resistor passageways are easier to clean than prior art internal bores, and that efficient cleaning can be done simply using a brush and soapy water, and can even include sterilization in a microwave oven.

[0097] Reference is now made to Fig. 8, which illustrate an example adaption to the device of Fig. 2, to enable the measurement of the viscosity of the milk to be determined, from which the fat content of the milk can be obtained. The device shown in Fig. 8 uses three pressure sensors Pl, P2 and P3, applied at the appropriate ends of the two hydraulic resistors, 71 and 70 respectively, as shown schematically in Fig. 7C above. A schematic representation of the resistors 70, 71, and their respective pressure sensors Pl, P2, P3, is shown in the enlarged insert of the combination resistor arrangement of Fig. 8. The outputs of the pressure sensors are input to the controller, 14 where the pressure measurements are used to determine the viscosity of the milk in real time. Referring back to equation (5), since APA and APB are the differential pressures measured in the arrangement of Fig. 8, and the flow rates through the two serial resistors are equal, and all of the other terms TA, I'B. LA, LB, are fixed properties of the resistors of the differential pressure flow measurement module of the device, the algorithm running on the controller can readily determine the value of p, the milk viscosity from the measured values of PA and APB.

[0098] As is advisable with all electronic measurement devices, some form of calibration and compensation for the drift of component values should be provided in the above described devices. Reference is now made to Fig. 9 and Figs. 10A to 10C, which illustrate an exemplary system and method of how such a calibration procedure can be provided for the devices of the present application. The system uses the optical bubble sensor system to check on the accuracy of the differential pressure system measurements. This procedure is realizable because the temporal accuracy of the optical measurements is higher and more definitive than the differential pressure measurements.

[0099] In Fig. 9, which is a development of the milk flow measurement device of Fig. 2, and using the same nomenclature as Fig. 2, there are shown three optical air bubble sensors in the optical measurement unit. Only a pair of those sensors are required for implementing this calibration method, and that pair could be sensors A and B, as shown in Fig. 10A, or sensors A and C, as shown in Fig. 10B, or sensors B and C, as is implied from Fig. 9. The pair of optical sensors are arranged along the milk channels at a known distance from each other. The system controller continuously monitors the optical transmission at each sensor of a pair, and attempts to detect signals arising from an air bubble passing, having a shape or magnitude or other characteristic feature, which is identified in both sensors of the pair as representing the same incident. The time T elapsed between equivalent temporal positions of the two events is recorded. Since the distance between the two sensors of the pair, and the cross section of the channel between them are both known, the volume of milk in the channel between the pair of sensors is known, and it is thus possible to calculate the amount of milk that has passed during the time T between the recording of the two events in the two sensors of the pair. Because of the well-defined point in time with which it is possible to detect a perturbation to the milk flow, such a milk flow measurement is accurate and reliable. Since air bubbles can have any length, a specific feature of each air bubble should be used, both in order to identify that the air bubble passing though the two sensors of the pair being used, is the same air bubble, and also to define a fixed point in time that is to be measured on both of the sensors so that the passage time is correctly measured.

[0100] The disadvantage of this optical sensor method is that it is dependent on waiting for a suitable air bubble which can be recorded on both sensors. Thus, the optical method of flow detection is less useful than the pressure sensor method, since the pressure sensor method can be performed continuously. However, the optical transit time method can serve as a calibration method for the accuracy of the differential pressure measurement system. This can be done by comparing the amount of milk obtained in the prescribed period of time between recording an air bubble event in the two optical sensors of the pair, as described in the previous paragraph, with the amount of milk calculated using the conventional differential pressure measurements performed using the pressure sensors 15 across the hydraulic resistor 11, as shown in Fig. IOC. Because of the higher reliability or accuracy of an air bubble transit time measurement, it can be assumed that any deviation between the two results is more likely to have arisen from change in the calibration of the differential pressure system, and the controller system can then correct the calibration of the pressure sensor system against the optical sensor system

[0101] This calibration procedure can be repeated whenever a new air bubble is detected, having characteristics enabling the accurate time determination mentioned above to be performed, thus providing regular accuracy updating for the flow measurement of the devices. Alternatively, this calibration procedure can be performed at predetermined intervals, as deemed necessary from a knowledge of the likelihood of drift in the differential pressure measurement system.

[0102] Reference is now made to Fig. 11, which illustrates schematically and in more detail, an alternative implementation of the previously briefly described embodiments of the milk flow measurement device 100, that previously described device having the calculation of the milk flow rate or the milk viscosity performed in the device itself by the device controller 14 in the electronic measurement head 13. In the alternative implementation of Fig. 11, the pressure measurement data can be transmitted by a short range wireless communication link 18, such as Bluetooth®, to a nearby computer or smart phone 110, which can perform such tasks as processing the data to provide the information important to the mother for display on a remote monitor screen such as the smartphone 110 itself. Information collected and transmitted, may include but is not limited to, the milk flow rate, the milk viscosity, or its fat content. This information can be transmitted or sent to a remote database located in the cloud 111. In this respect, the ability to display the required information on the remote monitor screen is especially advantageous, since it removes the information location screen away from the nipple device 100 itself, where it may be difficult for the mother to read the display information in real time. The displayed information may be moved to a convenient position, from where the mother can readily and more comfortably read the desired data without interrupting the infant’s feeding. As a less comprehensive alternative, the remote computer or smartphone 110 can be used merely as a monitor screen, while the processing of the data is performed on the electronic measurement head 13 of the device 100.

[0103] The description of these embodiments is now continued using the smartphone 110 as the exemplary remote device, since that is likely to be the prominent use. However, it is to be understood that the smartphone example described herein is not intended to limit this invention to only a smartphone, but is intended to include any remote computing device.

[0104] In Fig. 11, the nipple device 100 is shown with its associated electronic measurement head 13 in contact or communication with a smartphone 110, such as could be held by the nursing mother. The communication between the measurement head 13 and the smartphone 110 could be wirelessly, such as, but not limited to, using a Bluetooth® connection, or another wireless protocol capable of transmitting data information according to this subject disclosure. Alternatively, the measurement head 13 of the nipple device 100 could be wire- connected to the smartphone 110, such as by using a USB connection cord or other suitable wired connection.

[0105] The smartphone 110 may be used to receive inputs, such as the pressure data, and thus the smartphone’s processor to take over the computing operational functions of the electronic measurement head 13 of the nipple device 100. The smartphone’s processor may incorporate algorithms and routines running thereon. An advantage of this arrangement is that the electronic measurement head 13 can be made simpler and less costly. The smartphone 110 can also be used to send the data to a database in the cloud 111, most conveniently by means of a Wi-Fi connection, where previous data from the same mother and infant may be stored and maintained to demonstrate a chronological review of the development of the infant’s feeding pattern.

[0106] Referring now back to Fig. 11, the right-hand side of Fig. 11 illustrates a schematic block diagram of the main computing algorithms or flow measurement routines, which may be run and / or processed by a processor on the smartphone 110, to generate the desired output of information.

[0107] In step 112, the pressure readings, as obtained from the pressure sensors 15 in the electronic head of the device, are input into the flow measurement routine, and the routine then proceeds to step 113.

[0108] In step 113, the flow measurement routine calculates the milk flow rate in real time from the pressure readings detected by the pressure sensors 15, and the routine proceeds to step 119, and if relevant, also to step 114..

[0109] In step 119, the result of the calculated milk flow rate is displayed to the mother on a remote device, such as a display on a smartphone device that is visible to the mother in real time. Displaying the result on a remote device is an advantage to a mother who is currently breast feeding, and who can thus conveniently determine if her infant is ingesting enough milk at that particular time.

[0110] In step 114, for those milk flow nipple devices that include a serial pair of hydraulic resistors 70, 71, such as is shown in Fig. 8 hereinabove, the viscosity of the milk flow may be determined from the differential pressures obtained from the two serial hydraulic resistors and the known parameters of the milk flow passageways, such as by using the calculated solution of equation (5) hereinabove. The routine then proceeds to step 120.

[0111] In step 120, the measurement routine displays on the display device of the smartphone or computer, the milk viscosity obtained from step 114.

[0112] In step 115, simultaneously with step 112, the flow measurement routine processed on the smartphone may also determine and account for discrepancies from air bubbles in the milk flow path. The smartphone computing routine records the input points in time of the detection of air bubbles passing an optical sensor 20, as shown in Fig. 2 of the disclosure, The routine then proceeds to step 116.

[0113] In step 116, the routine prevents the algorithm of step 113 from using pressure measurement data received in the time period during which the air bubbles are detected by the optical sensor 20, since such air bubbles cause a perturbation in the measured pressure as they pass the pressure sensors. Furthermore, although there may be only a short time difference between the time of detection of an air bubble by the optical sensor 20, and the subsequent time when its effect is felt by a reduction in the pressures measured by the pressure sensor 15, the routine may be programmed to take any such delay into account, and to prevent the use of pressure data sensed, not only during the time of detection of the air bubble, but also for a predetermined short time period after detection of the air bubble, until it has cleared the pressure measurement sensors. The flow measurement routine may then proceed to step 113 and 114 as described above.

[0114] Finally, in steps 117 and 118, the routine performs a method of calibration of those milk flow measurement devices, by using a serial pair of optical air bubble sensors, as shown in Fig. 9 and Figs. 10A to 10C. Steps 117 and 118 can be timed by the system to be performed at any interval determined as likely to be necessary to maintain the accuracy of the pressurebased flow measurement of steps 112 and 113, or even, if deemed necessary, at every passage of a suitable air bubble.

[0115] In step 117, the transit time is measured for passage of an air bubble between the two optical sensors, and the milk flow is calculated by this alternate method. The routine then proceeds to step 118.

[0116] In step 118, the routine compares the value obtained in step 117, with that calculated in step 113 using the pressure sensor(s). Any difference is then used to adjust the calculation of the pressure sensor based flow measurements, in order to recalibrate that measurement channel from any changes that may have occurred therein.

[0117] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. Furthermore, it is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and sub-combinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.

Claims

CLAIMSWe claim:

1. A nipple device to measure a milk flow from a breast of a mother to a nursing infant, the nipple device comprising: a first passageway, opening onto an inside surface of a domed sucking protrusion of the nipple device, to convey milk from the breast of the mother to a location remote from the domed sucking protrusion, and a second passageway to convey the milk back from the remote location to at least one exit orifice in an outer surface of the domed sucking protrusion, from which the nursing infant feeds; a hydraulic resistor in a path between the first and second passageways, through which the milk from the mother to the nursing infant flows; a first pressure sensor and a second pressure sensor disposed relative to ends of the hydraulic resistor, such that a controller detects a differential pressure across the hydraulic resistor to provide a measure of the milk flow rate from the mother to the nursing infant; and an optical sensor adapted to measure an optical transmission across at least one of the passageways, such that the presence of at least one air bubble passing through the at least one passageway is detected by the optical sensor, wherein the controller is adapted to reject from the differential pressure data used to determine the milk flow rate, that data obtained during the duration of the presence of air bubbles in the milk flow.

2. The nipple device according to either one of the previous claims, wherein the optical sensor comprises a light source on one side of a passageway, and a light detector on an opposite side.

3. The nipple device according to claim 2, wherein the light detector can be either a photovoltaic detector or a photoresistor.

4. The nipple device according to any one of the previous claims, wherein the controller identifies the presence of an air bubble by detecting a change of more than a predetermined level occurring during less than a predetermined time, in the optical transmission measured by the optical sensor.

5. The nipple device according to any one of the previous claims, wherein the detection of air bubbles in the milk flow enables the accuracy of the milk flow rate to be improved over that of devices which do not take into account the presence of air bubbles in the milk flow.

6. A nipple device to determine a viscosity of a milk flow from a mother to a nursing infant, the nipple device comprising: passageways to convey milk from a breast of the mother to the nursing infant; a first hydraulic resistor and a second hydraulic resistor disposed serially in either order along the passageways, such that the milk flows serially through both of the hydraulic resistors, the first hydraulic resistor having a smaller cross sectional area than the second hydraulic resistor, such that the milk flows at a higher velocity through the first hydraulic resistor having the smaller flow cross sectional area than the milk velocity through the second hydraulic resistor having a larger cross sectional area; pressure sensors to measure the differential pressure of the milk flow across the first hydraulic resistor and across the second hydraulic resistor; and a control system adapted to determine the difference in differential pressures measured across the first hydraulic resistor and across the second hydraulic resistor, in order to calculate the viscosity of the milk flowing serially through the hydraulic resistors.

7. A nipple device according to claim 6, wherein the first hydraulic resistor having the smaller flow cross sectional area is a tube having a smaller cross sectional area than that of the second hydraulic resistor.

8. A nipple device according to claim 6, wherein the first hydraulic resistor having the smaller flow cross sectional area is an orifice having a smaller cross sectional area than that of the second hydraulic resistor.

9. A nipple device according to either one of claims 6 and 7, wherein the hydraulic resistors are tubular in shape, and the control system is adapted to base the calculation of the viscosity of the milk, on the relationship that the flow rate of the milk through a tubular hydraulic resistor is given by the expression:Q = AP nr4 / 8ptLwhere:Q is the flow rate of the milk,AP is the pressure differential across the ends of the tubular hydraulic resistor, r is the effective radius of the tubular hydraulic resistor, p is the viscosity of the milk, andL is the effective length of the tubular hydraulic resistor, and wherein use of an equal flow rate of the milk through the first and the second hydraulic resistors enables the viscosity of the milk to be determined.

10. A nipple device according to claim 9, wherein the control system is adapted to determine the viscosity of the milk without prior knowledge of the effective radius and effective length of the two resistors, by use of previously performed calibration measurements made at a number of different flow rates.

11. A self-calibrating nipple device to measure milk flow rate from a mother to a nursing infant, the self-calibrating nipple device comprising: an arrangement of passageways to convey milk from a breast of the mother to the nursing infant; a hydraulic resistor disposed along the passageways such that the milk flows through the hydraulic resistor in its path from the mother to the nursing infant; pressure sensors to measure the differential pressure of the milk flow across ends of the hydraulic resistor to determine the milk flow rate; a pair of optical air bubble sensors disposed at a predetermined distance apart along the passageways; and a control system adapted to determine the milk flow rate from the transit time of an air bubble feature between the pair of optical air bubble sensors, and to correct a measurement of the milk flow rate determined by the differential pressure measurement according to the milk flow rate determined by the transit time of an air bubble feature between the pair of optical air bubble sensors.

12. A self calibrating nipple device according to claim 11 wherein the air bubble feature enables a point in time of the passage of the air bubble to be determined, for an air bubble having a passage time longer than a predetermined minimum.

13. A self calibrating nipple device according to either one of claims 11 and 12, wherein the control system is adapted to perform a calibration by:(i) measuring the transit time of an air bubble feature between the pair of optical air bubble sensors disposed at a predetermined distance apart,(ii) determining the velocity of the milk flow, and(iii) further calculating the milk flow rate from a knowledge of the effective cross-section of the passageway between the pair of optical air bubble sensors, such that the calculated milk flow rate can be used to determine the accuracy of the milk flow rate obtained from the differential pressure measurement of the milk flow.

14. A self calibrating nipple device according to claim 13, wherein the velocity of the milk flow is known from a knowledge of the effective distance apart of the pair of optical air bubble sensors, and of the measured transit time of an air bubble feature between the pair of optical air bubble sensors.

15. A self calibrating nipple device according to claim 13, wherein the effective distance apart of the pair of optical air bubble sensors is determined either by measurement along the passageway, or by using a calibration procedure by measuring the amount of milk or alternative fluid passed in a predetermined time period.

16. A self calibrating nipple device according to any one of claim 11 to 15, wherein the control system is adapted to monitor the optical air bubble sensors at predetermined intervals, and to perform calibrations of the differential pressure measurement of the milk flow rate, from the milk flow rate determined by the air bubble feature transit time between the optical air bubble sensors.

17. A nipple device according to any one of claims 1 to 10, wherein the pressure data from the pressure sensors is sent to a remote computing device, where calculations are performed in order to provide at least one of the milk flow rate, or the milk viscosity.

18. A nipple device according to claim 17, wherein the measurements or at least one of the milk flow rate or the milk viscosity can be displayed on a screen of the remote computing device19. A nipple device according to either one of claims 17 or 18, wherein the measurements, or at least one of the calculated milk flow rate or the calculated milk viscosity can be sent wirelessly to a remote database for storage.

20. A nipple device according to any of claims 17 to 19, wherein the remote computing device is a smartphone.

21. A nipple device according to any of claims 1 to 12, wherein data regarding at least one of the milk flow rate, or the milk viscosity are sent to a remote computing device for at least one of display or storage or transmitting to a remote database.

22. A nipple device to measure a milk flow from a breast of a mother to a nursing infant, the nipple device comprising: a first passageway, opening onto an inside surface of a domed sucking protrusion of the nipple device, to convey milk from the breast of the mother to a location remote from the domed sucking protrusion, and a second passageway to convey the milk back from the remote location to at least one exit orifice in an outer surface of the domed sucking protrusion, from which the nursing infant feeds; a hydraulic resistor in a path between the first and second passageways, through which the milk from the mother to the nursing infant flows; and a first pressure sensor and a second pressure sensor disposed relative to ends of the hydraulic resistor, such that a controller detects a differential pressure across the hydraulic resistor to provide a measure of the milk flow rate from the mother to the nursing infant, wherein the presence of an air bubble in the milk flow can be identified by detecting a change of more than a predetermined level in the differential pressure measured across the hydraulic resistor, the change occurring during less than a predetermined time.

23. A nipple device according to claim 22, wherein the controller is adapted to reject from differential pressure data used to determine the milk flow rate, that data obtained during the duration of the presence of an air bubble in the milk flow.

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