Flow sensor system and method of use thereof

Abstract

A flow sensor system for detecting the presence or absence of flow of a liquid nutritional formulation through a conduit of an enteral feeding system. The flow sensor system includes a flow path configured to hold the conduit therein, a heat source disposed at a first location in a first portion of the conduit, and a heat detector disposed at a second location in a second portion of the conduit. The heat source can include an IR LED and the heat detector can include a thermopile sensor. A method for using the flow sensor system to detect the presence or absence of flow of a liquid nutritional formulation through a conduit of an enteral feeding system is also disclosed.

Description

[Technical field]

[0001] <Related Applications> This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 332,595, filed April 19, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates generally to a flow sensor system for use with an enteral feeding system and methods for using the same. [Background technology]

[0003] Generally, enteral feeding pump systems are used to provide liquid nutrition to patients who are unable to eat by mouth. The pump mechanism typically includes a pump 10 and a disposable tubing set (see FIG. 4). An exemplary enteral feeding pump is shown in FIG. 4 and is used with a disposable fluid delivery set having two separate source containers connected by tubing to a tubing adapter that combines the flows from the two separate tubes into a single fluid stream. Enteral feeding pumps may be used to separately pump only liquid nutrition formulas or nutrition formulas and water. Blockages in the tubing cause problems with reduced or stopped flow of liquid nutrition to the patient.

[0004] Therefore, there is a need for a flow sensor system that can reliably detect reduced flow and blockages in the conduits / tubing and that facilitates improving flow in the tubing of enteral feeding pumps. Summary of the Invention

[0005] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not intended to present an extensive overview of the invention. It does not identify or precisely outline key elements of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

[0006] According to one embodiment of the present invention, a flow sensor system for detecting the presence or absence of flow through a conduit of an enteral feeding system includes a flow path configured to hold the conduit therein, a heat source disposed at a first location in a first portion of the conduit, and a heat detector disposed at a second location in a second portion of the conduit.

[0007] In another embodiment, the heat source includes an IR LED.

[0008] In another embodiment, the heat detector includes a thermopile sensor.

[0009] In accordance with another embodiment of the present invention, a flow sensor system for detecting the presence or absence of flow through a conduit of an enteral feeding system includes: a flow path configured to hold the conduit therein; a heat source disposed at a first location in a first portion of the conduit, the heat source including an IR LED; a photodiode IR sensor at a location proximate to the IR LED, the photodiode IR sensor configured to be illuminated by the IR LED whereby the photodiode IR sensor is used to detect the presence of the conduit in the flow path; and a thermal detector disposed at a second location in a second portion of the conduit, the thermal detector including a thermopile sensor.

[0010] In accordance with another embodiment of the present invention, a method of detecting the presence or absence of flow of a liquid nutritional formulation through a conduit of an enteral feeding system comprises: providing a flow sensor system for detecting the presence or absence of flow through the conduit, the flow sensor system including a heat source disposed in a first portion of the conduit and a heat detector disposed in a second portion of the conduit; stopping the flow of the liquid nutritional formulation through the conduit; activating the heat source for a programmed interval to heat at least a portion of the liquid nutritional formulation in the conduit; resuming the flow of the liquid nutritional formulation through the conduit; monitoring a relative temperature of the liquid nutritional formulation passing through using the heat detector at the second portion, the second portion being downstream of the first location; and processing the relative temperature signal between the first location and the second location to determine the presence of a partial or complete blockage in the conduit.

[0011] According to another embodiment, a method of detecting the presence or absence of flow of a liquid nutritional formulation through a conduit of an enteral nutrition system comprises: providing a flow sensor system for detecting the presence or absence of flow through the conduit, the flow sensor system including a heat source disposed in a first portion of the conduit and a heat detector disposed in a second portion of the conduit; activating the heat source; determining a reference temperature T1 of the liquid nutritional formulation at a second location; measuring a second temperature T2 of the liquid nutritional formulation at the second location; calculating the difference between the reference temperature and the second temperature; and determining whether there is low or complete absence of flow of the liquid nutritional formulation from the difference between the reference temperature and the second temperature, thereby indicating a partial or complete blockage in the conduit, respectively.

[0012] These and other features and advantages will become apparent from a reading of the following detailed description and a review of the associated drawings. Also, it is to be understood that the foregoing general description and the following detailed description are merely explanatory and are not restrictive of the aspects claimed. [Brief description of the drawings]

[0013] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to explain the objects, advantages, and principles of the present invention. The embodiments of the present invention are in no way limited by the following drawings:

[0014] [Figure 1] 1 illustrates components of an exemplary flow sensor system according to the present invention, showing unobstructed flow of a liquid (e.g., a formulation);

[0015] [Diagram 2] 2 illustrates the exemplary flow sensor system of FIG. 1 showing an obstructed flow;

[0016] [Diagram 3] FIG. 1 shows components of a flow sensor system;

[0017] [Figure 4] 1 illustrates an exemplary enteral feeding pump for use with the flow sensor system of the present invention;

[0018] [Diagram 5] 1 is a graph of fluid temperature in an enteral feeding pump used with the flow sensor system of the present invention;

[0019] [Figure 6] 1 is a top perspective view of an embodiment of an enteral feeding pump system having a flow sensor system in accordance with the present invention;

[0020] [Figure 7] FIG. 7 is an exploded front view of the flow sensor system of FIG. 6 showing a channel for receiving a flexible tube therein;

[0021] [Figure 8] 7 is an assembled front view of the flow sensor system of FIG. 6 showing the flexible tube inserted into the flow path;

[0022] [Figure 9] FIG. 7 is a rear view of the flow sensor system of FIG. 6 showing its various components;

[0023] [Figure 10] 1 is a block diagram of an embodiment of an enteral feeding pump with flow sensor system and control in accordance with the present invention;

[0024] [Figure 11] FIG. 1 is a block diagram of an embodiment of an enteral feeding pump in accordance with the present invention, including a schematic diagram of an empty tube detected by a photodiode illuminated by an IR LED operating at low power;

[0025] [Figure 12] FIG. 1 is a block diagram of an embodiment of an enteral feeding pump in accordance with the present invention, including a schematic diagram of fluid-filled tubing attenuated photodiode illumination that allows for determination and control of flow function;

[0026] [Figure 13] FIG. 1 is a block diagram of an embodiment of an enteral feeding pump in accordance with the present invention, including a schematic diagram of a fluid-filled tube in a no-flow state with an IR high power LED radiating sufficient energy to increase the fluid temperature;

[0027] [Figure 14] FIG. 1 is a block diagram of an embodiment of an enteral feeding pump system in accordance with the present invention, including a schematic diagram of a fluid-filled tube in a no-flow state with the fluid temperature elevated by an IR LED;

[0028] [Figure 15] FIG. 1 is a block diagram of an embodiment of an enteral feeding pump system in accordance with the present invention, including a schematic diagram of a fluid-filled tube with flowing fluid and a high temperature region moving downstream;

[0029] [Figure 16]FIG. 2 is a block diagram of an embodiment of an enteral feeding pump system according to the present invention, including a schematic diagram of a fluid-filled tube having a flowing fluid, where a high temperature region passing through a thermopile causes a voltage output versus time that is compared to various responses stored in a controller memory, such that the absence of fluid flow can be determined by comparison;

[0030] [Figure 17] 11 is a graph showing example voltage variations for occlusion and normal flow compared to reference limits stored in the controller memory in one embodiment of an enteral feeding pump system according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] For clarity and convenience, the meanings of some terms and phrases used in the specification, examples, and appended claims are provided below. Unless otherwise specified or implied from the context, the following terms and phrases include the meanings provided below. The definitions are provided to help explain certain embodiments and are not intended to limit the claimed invention, since the scope of the invention is limited only by the claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs. If there is an apparent discrepancy between the use of a term in the art and its definition provided herein, the definition provided herein shall prevail.

[0032] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless they clearly dictate otherwise.

[0033] As used herein, the term "approximately" or "about" in reference to a value or parameter is generally interpreted as including numbers within 5%, 10%, 15%, or 20% in either direction (greater or less) of that number, unless otherwise stated or clear from the context (unless the number is less than 0% or more than 100% of the possible values). As used herein, when a value or parameter is "approximately" or "about", it includes (and is so described as) embodiments that are directed to that value or parameter. For example, a description that refers to "about X" includes a description of "X".

[0034] As used herein, the term "or" means "and / or." When used herein in phrases such as "A and / or B," it is intended to include both A and B; A or B; A (alone); and B (alone). Similarly, the term "and / or" when used in phrases such as "A, B, and / or C" is intended to encompass each of the following embodiments: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); C (alone).

[0035] As used herein, the term "comprising" means that other elements may be present in addition to the defined elements presented. The use of "comprising" indicates inclusion rather than limitation.

[0036] The term "consisting of" refers to compositions, methods, and their respective components described herein, which exclude any element not recited in that description of an embodiment.

[0037] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent that the present invention may be practiced without such specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the present invention.

[0038] Reference will now be made in detail to the presently disclosed embodiments of the invention, examples of which include like reference numerals referring to like elements throughout.

[0039] An embodiment of the flow sensor system of the present invention uses thermal drift to measure the presence or absence of fluid flow (rather than the flow rate / flow rate) of a liquid nutritional formula in an enteral feeding pump (i.e., designated by reference numeral 10 in FIG. 4). The liquid is heated at a first location and the arrival of the liquid is sensed at a second downstream location. This approach can determine the presence or absence of flow (i.e., blockage). The flow sensor system is housed within the flow detector module of the enteral feeding pump in some embodiments.

[0040] 3, in various embodiments, the flow sensor system 20 includes an IR LED 30 as a heat source at a first location on one side / end of a conduit 40 (e.g., a PVC tube or other medical grade material tube). In various embodiments, the flow sensor system 20 further includes a thermopile sensor 50 as a heat detector at a second location on the opposite side / other end of the conduit 40.

[0041] The operation of the flow sensor system 20 according to one embodiment of the present invention will now be described. The liquid flow of the liquid nutritional formulation is stopped and the heat source 30 at a first location (e.g., IR LED) is activated for a programmed length of time to heat at least a portion of the liquid nutritional formulation in the conduit 40. The liquid flow is then resumed. The relative temperature of the passing liquid nutritional formulation is monitored by a thermal sensor at a downstream location (e.g., thermopile sensor 50). Processing of the relative temperature signal reveals low or complete absence of flow of the liquid nutritional formulation, which indicates partial or complete blockage in the conduit 40, respectively. The temperature change measured by the thermopile sensor 50 thus provides a meaningful signal for assessing flow and blockage in the conduit.

[0042] FIG. 5 is a graph of fluid temperature in an enteral feeding pump used with the flow sensor system of the present invention. The X-axis is time (seconds) and the Y-axis is relative temperature (dimensionless raw data, output temperature compared to a reference temperature). The darker lines indicate the relative temperature of the fluid passing through the thermopile sensor. The temperature rises from a base level and returns to the base level as cooler fluid displaces hotter fluid. This is indicative of normal flow through the enteral feeding pump tubing / conduit. The lighter lines indicate the fluid temperature rising as heat spreads from the heat source (IR LED). After a period of time, the temperature stabilizes at a relatively high level as the fluid stagnates and there is no cooler fluid entering the tubing in close proximity to the thermopile. This indicates abnormal (occluded / blocked) flow through the enteral feeding pump tubing / conduit.

[0043] 6-9 are now described which illustrate an embodiment of a flow sensor system 120 for use with enteral feeding pump 100 (shown in FIG. 6). Unless otherwise indicated, the operation and components of flow sensor system 120 are the same as or generally similar to flow sensor system 20 described above and shown in FIGS. 1-4.

[0044] As shown in FIGS. 7 and 8, the front portion 122 of the flow sensor system 120 defines a flow passage 124 configured to receive a conduit 140 (eg, PVC tubing) therein.

[0045] 9, in various embodiments, the flow sensor system 120 includes a rear portion 126 incorporating an IR LED 130 (e.g., an IR high power LED) as a heat source at a first location on one side / end of the conduit 140. In various embodiments, the flow sensor system 120 further includes a thermopile sensor 150 as a heat detector at a second location on the opposite side / other end of the conduit 140. In various embodiments, the flow sensor system 120 further includes a photodiode IR sensor 160 located proximate to the IR LED 130 configured to be illuminated by the IR LED 130. The photodiode IR sensor 160 is used to detect the presence of the conduit 140 (tube) within the flow path 124. This information is used to prevent false alarms when the conduit 140 is not in the proper location (i.e., within the flow path 124).

[0046] 10-16, a series of block diagrams of an enteral feeding pump 200 and an embodiment of a flow sensor system 220 (also referred to as a thermal drift flow sensor) for use with an enteral feeding pump are described. Unless otherwise indicated, the operation and components of flow sensor system 220 are the same as or generally similar to flow sensor systems 20 and 120 discussed above and shown in FIGS. 1-4 and 6-9.

[0047] 10 shows an enteral feeding pump 200 including a flow sensor system 220 having a dual mode IR LED 230, a thermopile heat sensor 250, and a photodiode IR sensor 260. The IR LED 230, the thermopile heat sensor 250, and the photodiode IR sensor 260 are all operatively connected to a controller (with memory) 270 of the enteral feeding pump 200. In various embodiments, the controller 270 also operatively connects to other components of the enteral feeding pump 200 including a touch screen display 280, a pump motor 290, a keypad 300 with AC / battery LEDs, and a piezo alarm 310.

[0048] The block diagram of Figure 11 includes a schematic diagram of an enteral feeding pump 200 having an empty tube (i.e., conduit) 240 that is detected by a photodiode IR sensor 260 that is illuminated by an IR LED 230 operating at low power. The photodiode IR sensor 260 is used to detect the presence of tubing / conduit 240, i.e., in the flow path (not shown). This information is used to prevent false alarms when the conduit 240 is not in the proper position.

[0049] The block diagram of FIG. 12 includes a schematic diagram of an enteral feeding pump 200 having fluid-filled tubing 240 and attenuated photodiode illumination (i.e., from IR LED 230) that illuminates a photodiode IR sensor 260 to indicate the status of the tubing / conduit 240, thereby facilitating determination and control of the flow function of the enteral feeding pump 200.

[0050] The block diagram of FIG. 13 includes a schematic diagram of an enteral feeding pump 200 with a tube 240 filled with fluid and in a no-flow state, with an IR LED 230 emitting enough energy E to raise the fluid temperature of the fluid in the tube 240. For purposes of this disclosure, "sufficient energy" is defined as the minimum amount of energy required to resolve a distinct signal. This is a function of the resolution of the electronics and thermopile heat sensor 250. Too much energy can cause the system to overheat.

[0051] The block diagram of Figure 14 includes a schematic of an enteral feeding pump 200 with tubing 240 filled with fluid and in a no-flow state, where a portion of the fluid T has its temperature increased by IR LEDs 230. In one embodiment, the temperature is increased by approximately 3.5°C. The block diagram of Figure 15 includes a schematic of an enteral feeding pump 200 with tubing 240 filled with flowing fluid, where the portion of the fluid T having the higher fluid temperature moves downstream with the fluid flow.

[0052] 16 is a block diagram including a schematic diagram of an enteral feeding pump 200 having a tube 240 filled with flowing fluid at fluid portion T having a high fluid temperature passing through a thermopile 250. Such passage causes a voltage output versus time as shown in the inset graph of FIG.

[0053] FIG. 17 is a graph of voltage output versus time for response curves for high and low normal flows (solid lines), high and low occluded flows (dotted lines), and high and low reference flows (dashed lines) stored in controller memory 270. Comparison between the curves allows the user to determine the presence or absence of fluid flow. The time may range from 10 seconds to 240 seconds. Values ​​that cross the high or low dashed curves of the reference flow value represent occluded flows (i.e., dotted curves).

[0054] In another embodiment of the present invention, a method for detecting the presence or absence of flow of a liquid nutritional formulation through a conduit of an enteral nutritional system comprises the steps of: (1) providing a flow sensor system for detecting the presence or absence of flow through the conduit, the flow sensor system including a heat source disposed at a first location in a first portion of the conduit and a heat detector disposed at a second location in a second portion of the conduit; (2) activating the heat source; determining a reference temperature T1 of the liquid nutritional formulation at the second location; measuring a second temperature T2 of the liquid nutritional formulation at the second location; (3) calculating the difference between the reference temperature and the second temperature; and (4) determining from the difference between the reference temperature and the second temperature whether there is low or complete absence of flow of the liquid nutritional formulation, thereby indicating a partial or complete blockage, respectively, in the conduit.

[0055] Modifications, additions, or omissions may be made to the systems, devices, and methods described herein without departing from the scope of the disclosure. For example, system and device components may be integrated or separated. Furthermore, the operations of the systems and devices disclosed herein may be implemented with more, fewer, or other components, and the methods described may include more, fewer, or other steps. Furthermore, steps may be performed in any suitable order. As used herein, "each" refers to each member of a set or each member of a subset of a set.

[0056] Other aspects of the invention will be apparent to those skilled in the art from the specification and practice of the invention disclosed herein. While certain advantages have been enumerated above, various embodiments may include some, none, or all of the enumerated advantages. It is intended that the above-described embodiments be considered as exemplary only, with the true scope and spirit of the invention being indicated by the appended claims. Moreover, any feature disclosed herein should not be construed as an essential element, and thus, a disclosed feature should not be construed as part of the claimed invention unless that feature is specifically recited in the claims. In addition, it should be understood that any feature disclosed in any particular embodiment may be incorporated in whole or in part into any of the other disclosed embodiments.

[0057] In interpreting any of the claims appended hereto, it should be noted that, unless the words "means for" or "step for" are expressly used in a particular claim, no claim or claim element is intended to be governed by or construed in accordance with 35 U.S.C. 112(f).

[0058] In general, any combination of the disclosed features, components, and methods described herein is possible. The steps of the method can be executed in any order that is physically possible.

[0059] All cited references are incorporated herein by reference.

[0060] Although embodiments have been disclosed, it is not desired to be limited thereby, but rather the scope should be determined only by the appended claims.

[0061] While various embodiments of the present disclosure have been described in detail, it will be apparent that modifications and variations of these embodiments will occur to those skilled in the art, but it is to be clearly understood that such modifications and variations are within the scope and spirit of the present disclosure, as set forth in the following claims.

[0062] The foregoing discussion of the present disclosure has been presented for purposes of illustration and description. The foregoing is not intended to limit the present disclosure to the form disclosed herein. For example, in the foregoing detailed description, various features of the present disclosure are grouped together in one or more embodiments for the purpose of simplifying the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, no inventive element resides in every feature of a single preceding disclosed embodiment. Thus, the following claims are hereby incorporated into this detailed description, with each claim standing on its own as a separate preferred embodiment of the present disclosure.

[0063] Furthermore, although the present disclosure includes one or more embodiments and a description of certain modifications and variations, other modifications and variations are within the scope of the present disclosure, for example, as would be within the skill and knowledge of one of ordinary skill in the art after understanding the present disclosure. It is intended to be entitled to include alternative embodiments to the extent permitted, including alternative, interchangeable, and / or equivalent structures, functions, ranges, or steps to those claimed. The above is regardless of whether such alternative, interchangeable, and / or equivalent structures, functions, ranges, or steps are disclosed in the present application. Also, there is no intention to make any patentable subject matter publicly available.

[0064] In general, any combination of the disclosed features, components, and methods described herein is possible. The method steps can be executed in any order that is physically possible.

Claims

1. 1. A flow sensor system for detecting the presence or absence of flow through a conduit of an enteral feeding system, comprising: a flow channel configured to hold the conduit therein; a heat source disposed at a first location in a first portion of the conduit; a heat detector disposed at a second location in the second portion of the conduit; A flow sensor system comprising:

2. The flow sensor system of claim 1 , wherein the heat source comprises an IR LED.

3. 3. The flow sensor system of claim 2, further comprising a photodiode IR sensor positioned adjacent to the IR LED, the photodiode IR sensor configured to be illuminated by the IR LED, whereby the photodiode IR sensor is used to detect the presence of the conduit within the flow path.

4. The flow sensor system of claim 2 , wherein the IR LED is configured to increase a temperature of a portion of the fluid within the conduit.

5. 5. The flow sensor system of claim 4, wherein the temperature increase is approximately 3.5 degrees Celsius.

6. The flow sensor system of claim 4 , wherein the fluid portion having the elevated fluid temperature moves downstream through the conduit with the fluid flow.

7. 7. The flow sensor system of claim 6, wherein the fluid portion having the elevated fluid temperature passes through the thermal detector, the passage causing a voltage output versus time.

8. The flow sensor system of claim 7, wherein the time period is in the range of 10 seconds to 240 seconds.

9. 8. The flow sensor system of claim 7, further comprising a controller memory, and wherein the voltage output versus time is compared to a response curve stored in the controller memory, whereby the comparison enables a user to determine whether or not there is fluid flow in the conduit.

10. The flow sensor system of claim 9 , wherein the response curves stored in the controller memory include a response curve to a reference flow.

11. The flow sensor system of claim 1 , wherein the thermal detector comprises a thermopile sensor.

12. 1. A flow sensor system for detecting the presence or absence of flow through a conduit of an enteral feeding system, comprising: a flow channel configured to hold the conduit therein; a heat source disposed at a first location in the first portion of the conduit, the heat source including an IR LED; a photodiode IR sensor located proximate to the IR LED, the photodiode IR sensor configured to be illuminated by the IR LED, whereby the photodiode IR sensor is used to detect the presence of the conduit within the flow path; a heat detector disposed at a second location in the second portion of the conduit, the heat detector including a thermopile sensor; A flow sensor system comprising:

13. The flow sensor system of claim 12 , wherein the IR LED is configured to increase a temperature of a portion of the fluid within the conduit.

14. The flow sensor system of claim 13 , wherein the temperature increase is approximately 3.5° C.

15. The flow sensor system of claim 13 , wherein the fluid portion having the elevated fluid temperature moves downstream through the conduit with a fluid flow.

16. 16. The flow sensor system of claim 15, wherein the fluid portion having the elevated fluid temperature passes through the thermal detector, the passage causing a voltage output versus time.

17. 17. The flow sensor system of claim 16, wherein the time period is in the range of 10 seconds to 240 seconds.

18. 17. The flow sensor system of claim 16, further comprising a controller memory, wherein the voltage output versus time is compared to a response curve stored in the controller memory, whereby the comparison allows a user to determine the presence or absence of fluid flow in the conduit.

19. The flow sensor system of claim 18 , wherein the response curves stored in the controller memory include a response curve to a reference flow.

20. 1. A method for detecting the presence or absence of flow of a liquid nutritional formula through a conduit of an enteral feeding system, comprising: providing a flow sensor system for detecting the presence or absence of flow through a conduit, the flow sensor system having a heat source disposed at a first location in a first portion of the conduit and a heat detector disposed at a second location in a second portion of the conduit; stopping the flow of the liquid nutritional formulation through the conduit; activating a heat source for a programmed length of time to heat at least a portion of the liquid nutritional formulation within the conduit; resuming flow of the liquid nutritional formulation through the conduit; monitoring the relative temperature of the liquid nutritional formula passing therethrough using the heat detector at the second location, the second location being downstream of the first location; processing a relative temperature signal between the first location and the second location to determine the presence of a partial or complete blockage in the conduit; The method according to claim 1,

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