Fluid Collection Device for Accurate NPWT Flow Sensing
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Solution Overview
Problem
In negative pressure wound therapy (NPWT), measuring the flow rate of fluid from a wound is challenging due to the mixture of air and liquid, especially when the canister is not oriented correctly, leading to inaccurate readings and assessments of wound healing.
Innovation Solution
A fluid collection device with a housing, reservoir, and channel dividers that separates air from liquid, allowing liquid to accumulate and be released as a measurable slug, which is then detected by sensors, and a sensing system that includes a source of negative pressure and infrared sensors to accurately measure the fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a canister is used to collect fluid in NPWT, then the volume of fluid collected can be sensed, but the canister orientation uncertainty leads to false readings and inaccurate assessment
Solution Approach 1:
The device segments the fluid collection path into distinct functional zones: a reservoir for initial collection, multiple parallel channels with dividers for separation, and a liquid collection region for measurement. This segmentation allows the system to process air-liquid mixtures effectively regardless of orientation by directing liquid through specific pathways while allowing air to bypass.
Solution Approach 2:
The channel dividers act as intermediary structures that mediate between the incoming air-liquid mixture and the measurement system. These dividers create a controlled interface where liquid is separated and directed into the liquid collection region, while air is diverted through alternative paths, enabling accurate measurement independent of canister orientation.
2Productivity
If fluid flow is measured directly at the wound site, then the flow rate can be monitored, but the presence of air-liquid mixture makes measurement challenging
Solution Approach 1:
The device extracts the liquid phase from the air-liquid mixture by utilizing the channel dividers and liquid collection region. Liquid is pulled from the mixture through capillary action and pressure differential into dedicated measurement channels, while air is excluded from the measurement path. This extraction enables accurate liquid flow measurement without the interference of air bubbles.
Solution Approach 2:
Different regions of the device have specialized local properties: the reservoir provides initial collection space, the channel dividers create separation zones with specific surface tensions, and the liquid collection region is designed with dimensions optimized for liquid holding and measurement. This local quality differentiation enables effective air-liquid separation and accurate measurement.
3Reliability
If small quantities of liquid accumulate in the fluid collection device, then air can pass through, but significant volume liquid must be released as a slug for measurement
Solution Approach 1:
The device transitions from a static collection state to a dynamic measurement state. Small quantities of liquid are held in the reservoir and channels where air can bypass, but when liquid accumulates to a significant volume, the system dynamically releases it as a slug through the detection conduit. This dynamic behavior enables reliable measurement while maintaining simple air passage during normal operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively measures the flow rate of fluid by distinguishing between air and liquid, providing accurate data on wound exudate flow, independent of canister orientation, thus enhancing the assessment of wound healing.
Implementation Method 1
a plurality of channel dividers positioned within the housing between the reservoir and the distal end of the housing, the plurality of channel dividers having a proximal end and a distal end; wherein the plurality of channel dividers define a plurality of fluid channels within the housing
Implementation Method 2
a liquid collection region positioned within the housing between the distal end of the plurality of channel dividers and the distal end of the housing
Implementation Method 3
applying a negative pressure from the source of negative pressure to the fluid collection device to draw a fluid mixture of liquid and air through the inlet of the fluid collection device
Implementation Method 4
a sensing device comprising: a casing having an inlet, a source of negative pressure and a plurality of sensors; the inlet of the sensing device casing configured to be in fluid communication with the outlet of the canister
Data Source
AI summary
Devices and methods for collecting and sensing fluid flow are provided.