JP-7856585-B2 - Capillary action-based pressure threshold sensor for liquids, and method and apparatus using the same.

JP7856585B2JP 7856585 B2JP7856585 B2JP 7856585B2JP-7856585-B2

Inventors

スティーブビギン
ジョンアダムズ
ダニエルアブード
モーリスカーティン

Assignees

ベクトン・ディキンソン・アンド・カンパニー

Dates

Publication Date: 20260511
Application Date: 20210525
Priority Date: 20210521

Claims (20)

A method for fabricating a capillary action-based pressure threshold sensor, The selection of a first porous medium having porous properties that allow fluid to leak from a first side of the first porous medium to an opposing second side through the first porous medium, wherein the leakage occurs when the fluid pressure exceeds the fluid breakthrough pressure threshold of the first porous medium. To provide a fluid detection element positioned at least proximal to the second surface of the first porous medium and configured to detect the presence of at least a target fluid on the second surface of the first porous medium, Methods that include...
The fluid detection element is selected from a passive fluid detection element and an active fluid detection element. The method according to claim 1, wherein the passive fluid detection element remains inactive until the target fluid leaks through the first porous medium and reaches the opposing second side of the first porous medium, and the active fluid detection element provides different outputs to distinguish between a first state in which the target fluid has not yet leaked through the first porous medium and a second state in which the target fluid has leaked through the first porous medium, and/or the fluid detection element includes an indicator element configured to change state when the target fluid leaks through the first porous medium to the second side, the changing state being selected from a color indicator and a change in color indicator, and/or the first porous medium is coated with a thermoresponsive material to detect a state selected from a specified temperature and a specified pressure change of the target fluid, and/or the first porous medium is coated with a thermoresponsive material to detect a state selected from a specified temperature and a specified pressure change of the target fluid, the thermoresponsive material being poly-N-isopropylacrylamide (PNIPAM).
The method according to claim 1, wherein the porous properties of the first porous medium are selected from pore size, thickness, material, surface shape, coating, and contact angle with the fluid.
The method according to claim 1, further comprising: forming a seal over a hole in the flow path to expose the first porous medium to the fluid in the flow path and to configure the first side surface to prevent the fluid from leaking out of the capillary action-based pressure threshold sensor.
The fluid detection element includes at least two electrodes, To provide a second porous medium with affinity, positioned between a first porous medium with a non-affinity and the fluid detection element, such that the second porous medium is selected to have different conductivity when dry and when wet with fluid in the flow path, thereby controllingly distributing the fluid leaking through the first porous medium to a sensor, The method according to claim 1, further comprising providing two electrodes that contact the second side surface of a first porous medium, wherein the electrodes are passive and configured not to be activated until a fluid leaking through the first porous medium exceeds a threshold, and/or providing a fluid sensing element, comprising providing electrodes fabricated from contact pads on a printed circuit board (PCB), and/or the method further comprising thermal crimping the PCB via thermal crimping pins configured to maintain proximity to the second porous medium and maintain direct contact with the first porous medium.
The method according to claim 1, further comprising: the fluid detection element including at least two electrodes, and the electrodes acting as passive switches that are open until they come into contact with a fluid and close.
Providing a switch comprises providing an electrode made of contact pads on a printed circuit board (PCB), and/or the method further comprises connecting one electrode to a ground pin of a microcontroller and the other electrode to an input pin of a microcontroller, and/or the method further comprises connecting one electrode to an output pin of a microcontroller and the other electrode to an input pin of a microcontroller, and/or the method further comprises connecting one electrode to the positive rail of a power supply having a common ground with the microcontroller and the other electrode to an input pin of a microcontroller, and/or the method further comprises connecting a pull-up resistor between the positive rail of the power supply or reference voltage of the microcontroller and the input pin, and/or the method further comprises connecting a pull-down resistor between the input pin and the negative rail connected to the negative or ground terminal of the microcontroller, and/or the resistor having a resistance of about 1 k ohm to 100 M ohm, according to claim 6.
The method according to claim 1, wherein the first porous medium is selected from hydrophobic media, superhydrophobic media, oleophobic media, and porous media that are both incompatible.
The method further includes selecting a second porous medium positioned at least proximal to a first side of the first porous medium so as to be in contact with the target fluid before the target fluid leaks through the first porous medium, The second porous medium is The method according to claim 1, wherein the second porous medium has porous properties that allow a fluid to easily penetrate into the second porous medium, and porous properties that prevent a gas from passing through the second porous medium after the target fluid has penetrated into the second porous medium until the gas exceeds the intrusion pressure of the second porous medium, and/or the method further comprises selecting a second porous medium located at least proximal to the opposite side of the first porous medium so as to be in contact with the target fluid before the target fluid leaks through at least the first porous medium, the second porous medium having one or more porous properties that allow a fluid to easily penetrate into the second porous medium and enhance contact between the target fluid and the fluid sensing element.
A method using a capillary action-based pressure threshold sensor, Selecting an overpressure threshold detected by the fluid, Select a capillary action-based pressure threshold sensor comprising a porous medium having at least one porous property and a fluid breakthrough overpressure threshold related to the overpressure threshold, wherein the capillary action-based pressure threshold sensor allows fluid to leak from one side through the porous medium to the other side when the fluid pressure crossing the porous medium exceeds the fluid breakthrough overpressure threshold. The capillary action-based pressure threshold sensor is positioned such that the opposite side of the porous medium is in contact with the fluid where the overpressure event is detected, To provide a fluid detection element positioned at least proximal to the opposite side of a porous medium and configured to detect the presence of at least a target fluid on the opposite side of the porous medium, Methods that include...
The method according to claim 10, further comprising providing a flow channel and selecting a location where an overpressure event should be detected by a capillary action-based pressure threshold sensor, and/or the method further comprising providing a fluid vessel and selecting a location where an overpressure event should be detected by a capillary action-based pressure threshold sensor, and/or the method further comprising providing a hole at the selected location and sealing the hole by fixing a porous medium over the hole, and/or the method further comprising welding the porous medium to a material forming a flow channel.
A capillary action-based pressure threshold sensor comprises at least two electrodes, further comprising: causing the electrodes to act as passive switches that remain open until they are closed in contact with a fluid; and/or the method further comprises: triggering a notification when the passive switches are closed; and/or the triggering is selected from: providing an input associated with the notification to a microcontroller connected to the electrodes; and generating a notification by inducing a change in an indicator element in response to the fluid coming into contact with at least one side of a porous medium; and/or the method further comprises: connecting one of the electrodes to a ground pin of the microcontroller and the other electrode to an input pin of the microcontroller; and/or the method further comprises: connecting one of the electrodes to an output pin of the microcontroller and the other electrode to an input pin of the microcontroller; and/or the method further comprises: connecting one of the electrodes to the positive rail of a power supply having a common ground with the microcontroller and the other electrode to an input pin of the microcontroller; and/or The method according to claim 10, further comprising connecting a pull-up resistor to the positive rail or reference voltage of a power supply for the microcontroller and the input pins, and/or connecting a pull-down resistor between the input pins and the negative rail connected to the negative or ground terminal of the microcontroller, and/or the resistor having a resistance of about 1 k ohm to 100 M ohms.
The method according to claim 10, wherein the porous medium is selected from hydrophobic, superhydrophobic, oleophobic, and both inaffeminate porous mediums, and/or the porous properties of the porous medium are selected from pore size, thickness, material, surface shape, coating, and contact angle with fluid.
A capillary action-based pressure threshold sensor, A first porous medium having at least one porous property and a fluid breakthrough pressure threshold that allows fluid to leak from its first side to its opposing second side when the fluid pressure exceeds the fluid breakthrough threshold of the first porous medium, A fluid detection element is positioned at least proximal to a second surface of a first porous medium and configured to detect the presence of at least a target fluid on the second surface of the first porous medium. A pressure threshold sensor equipped with the following features.
The pressure threshold sensor according to claim 14, further comprising two electrodes in contact with a second side surface of a first porous medium, and/or the first porous medium is selected from a hydrophobic medium, a superhydrophobic medium, an oleophobic medium, and a porous medium of both aphids, and/or at least one porous property of the first porous medium is selected from pore size, thickness, material, surface shape, coating, and contact angle with fluid.
The pressure threshold sensor according to claim 14, further comprising at least a second porous medium positioned at least proximal to a first side of the first porous medium so as to be in contact with the target fluid before the target fluid leaks through the first porous medium, wherein the second porous medium has one or more porous properties that allow the fluid to easily penetrate the second porous medium and prevent the gas from passing through the second porous medium after it has penetrated with the target fluid until the gas exceeds the intrusion pressure of the second porous medium, and/or further comprising at least a second porous medium positioned at least proximal to the opposite side of the first porous medium so as to be in contact with the target fluid before the target fluid leaks through the first porous medium, wherein the second porous medium has one or more porous properties that allow the fluid to easily penetrate the second porous medium and enhance contact between the target fluid and the fluid sensing element.
The pressure threshold sensor according to claim 16, wherein the second porous medium is selected from hydrophilic, superhydrophilic, lipophilic, and biaffinity porous mediums, and/or the second porous medium is selected from a material that swells upon contact with a fluid in a channel, and the fluid detection element acts as a passive switch activated by the swelling of the second porous medium, and/or the fluid detection element comprises two electrodes in contact with the second porous medium, and/or the second porous medium is selected to have different conductivity when dry and when wet with a fluid in a channel, and/or the fluid detection element comprises two electrodes consisting of contact pads on a printed circuit board (PCB), and/or the PCB is heat-crimped via heat-crimping pins to maintain proximity to the second porous medium and direct contact with the first porous medium.
The fluid sensing element includes at least two electrodes that act as passive switches that are open until they come into contact with a fluid and close, and/or the sensor further comprises an indicator element configured to change state when a target fluid leaks through a first porous medium to a second side of the first porous medium, the changing state being selected from a color indicator and a change in color indicator, and/or the fluid sensing element, when closed, produces a notification that can be processed by a microcontroller connected to the electrodes, and/or one electrode is connected to a ground pin of the microcontroller and the other electrode is connected to an input pin of the microcontroller, and/or one electrode is connected to an output pin of the microcontroller and the other electrode is connected to an input pin of the microcontroller, and/or one electrode is connected to the positive rail of a power supply having a common ground with the microcontroller and the other electrode is connected to an input pin of the microcontroller, and/or the sensor further comprises a pull-down resistor connected between the input pin and a negative rail connected to a negative or ground terminal of the microcontroller, and/or The pressure threshold sensor according to claim 14, further comprising a pull-up resistor connected to the positive rail of a power supply or reference voltage for a microcontroller and an input pin, and/or the pull-up resistor having a resistance of about 1 k ohm to 100 M ohms.
The pressure threshold sensor according to claim 14, wherein the fluid detection element is passive and remains unactivated until the target fluid leaks through the first porous medium and reaches the second side opposite the first porous medium, or the fluid detection element is active and provides different outputs to distinguish between a first state in which the target fluid has not yet leaked through the first porous medium and a second state in which the target fluid has leaked through the first porous medium.
The pressure threshold sensor according to claim 14, further comprising a thermally responsive material coating a first porous medium, for detecting a state selected from a specified temperature and a specified pressure change in a target fluid, and/or the thermally responsive material is poly-N-isopropylacrylamide (PNIPAM).

Description

This disclosure broadly relates to a detection system capable of detecting excessive pressure events in a fluid line or flow path. This disclosure also relates to a capillary action-based pressure threshold sensor for liquids that utilizes the properties of a porous membrane to detect when a fluid passes through the membrane when the pressure crossing the membrane rises above the fluid's breakthrough pressure. Fluid delivery devices such as infusion pumps and infusion sets are known for delivering drugs or medications to patients over extended periods. Examples of infusion pumps include portable pumps (e.g., portable pumps), wearable or patch pumps, and larger, non-portable infusion pumps used in medical settings. An example of an infusion set includes a catheter assembly connected by a tubing set to a pump (e.g., Medtronic's MiniMedParadigm® insulin pump). These fluid delivery devices typically include one or more flow paths, such as tubing connected to an infusion set, or flow paths within an infusion set, including a catheter. Infusion pumps may have internal flow paths that move fluids, such as medications, from a container to a catheter. Obstructions can occur in these flow paths. Obstructions can be caused by biological, pharmacological, and/or mechanical blockages, for example, mechanical problems with the infusion device or by the fluid itself. Identifying partial or complete blockages is crucial in drug delivery applications, as failure to detect them can prevent patients from receiving the prescribed amount of medication. One potential failure mode that can occur due to an obstructed flow path is a pressure increase that can cause leakage in the flow path, preventing subsequent medication administration (one or more doses). Increased pressure in a fluid delivery system can also cause other problems, such as pump mechanism immobilization, pump mechanism deceleration and resulting increase in overall delivery time, pump mechanism damage due to increased force required to overcome the increased pressure, pump mechanism stall, and increased power consumption due to the pump mechanism operating at higher pressures. Therefore, an element is needed to detect blockage or pressure in the flow path. Considerations for integrating pressure sensing elements into wearable or disposable medical devices include reliability, stability, component size, and ability to integrate into the device, cost, power consumption, the need for (re)calibration, and the required computing power. Existing pressure sensors may be too expensive to add to injection devices while maintaining the device's target cost, and/or too unreliable to detect overpressure conditions, and/or may require specially sized hardware to read the values measured by the sensor, and/or may require excessive computing power to analyze the data provided by the pressure sensor. U.S. Patent Application Publication No. 2008/0129475U.S. Patent No. 10398852U.S. Patent No. 9,782,536International Publication No. 2016048878 The aforementioned problems and other issues are overcome by the exemplary embodiment, and further advantages are realized. Exemplary embodiments of this disclosure provide pressure detectors that can be miniaturized to achieve a small mounting area, use off-the-shelf or specially developed materials to meet specific requirements, achieve very low-cost products, represent fail-safe elements in flow paths when configured to be the weakest point in a fluid delivery system, have low power consumption (e.g., zero power consumption in some embodiments), require low computational power (e.g., zero computational power in some embodiments), are idle, and do not require calibration. An exemplary embodiment provides a method for fabricating a capillary action-based pressure threshold sensor, comprising: selecting a first porous medium having porous properties that allow fluid to leak from a first side of the porous medium to an opposing second side through the porous medium, wherein the leakage occurs when the fluid pressure exceeds a fluid breakthrough pressure threshold of the porous medium; and providing a fluid detection element positioned at least proximal to the second side of the porous medium and configured to detect the presence of at least a target fluid on the second side of the porous medium. According to an exemplary embodiment, the fluid detection element is selected from a passive fluid detection element and an active fluid detection element. The passive fluid detection element remains inactive until the target fluid leaks through the porous medium and reaches a second opposing side of the porous medium, while the active fluid detection element provides different outputs to distinguish between a first state in which the target fluid has not yet leaked through the porous medium and a second state in which the target fluid has leaked through the porous medium. According to an exemplary embodiment, the fluid detection element includes an indi