Grounded EMI Shielding for Bubble Detection Sensors
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Solution Overview
Problem
Fluid flow and bubble detection apparatuses, such as those used in Heart-Lung Machines, are unreliable during electro-surgery due to interference from high-energy radio frequency signals, leading to false positive bubble detections.
Innovation Solution
Incorporation of a separate electrically conductive EMI shielding between the sensor assembly and the housing, which is grounded, to prevent RF interference from affecting the fluid flow and bubble detection sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electro-surgery is performed in the surgical environment, then tissue cutting and cauterization can be achieved, but high-energy radio frequency signals are generated that interfere with fluid flow and bubble detection sensors
Solution Approach 1:
A grounded conductive shield is introduced as an intermediary component between the electro-surgical environment and the fluid flow/bubble detection sensors. This shield acts as a mediator that intercepts and redirects RF interference signals to ground, preventing them from reaching and affecting the sensor operations.
2Measurement precision
If fluid flow and bubble detection sensors are placed near the tube in the surgical field, then detection accuracy is improved, but the sensors become vulnerable to RF interference from electro-surgical equipment
Solution Approach 1:
The grounded conductive shield serves as a protective intermediary positioned between the electro-surgical RF sources and the detection sensors. It creates an electromagnetic barrier that allows the sensors to maintain their proximity to the tube for accurate detection while being protected from RF interference by the shield's grounding path.
3Reliability
If a grounded conductive shield is added to protect sensors from RF interference, then sensor reliability is improved, but device complexity increases
Solution Approach 1:
The EMI shield is implemented as a thin conductive layer or coating applied to the tube surface or sensor housing, rather than a bulky three-dimensional structure. This thin-film approach provides effective electromagnetic shielding while minimizing additional device complexity and maintaining a compact apparatus design.
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 EMI shielding effectively blocks RF noise induced in the fluid flow, ensuring accurate detection of fluid flow rates and bubbles without false positives during electro-surgery.
Implementation Method 1
an electrically grounded Electro-Magnetic Interference—EMI—shielding arranged between at least a part of the sensor assembly and the cavity such that it protects the sensor assembly from unwanted EMI
Implementation Method 2
an ultrasonic probe comprising an ultrasonic transducer array
Implementation Method 3
Ultrasonic transducers are positioned on both sides of the tube. Metal sound pipes are placed between the transducers and the tube to transport ultrasonic signals
Data Source
AI summary
A fluid flow sensing and bubble detecting apparatus, comprising: —housing provided with a cavity configured to receive a tube through which conductive fluid flows; —a fluid flow sensing and bubble detecting electrical sensor assembly supported by the housing and configured to sense the flow of the fluid flowing through the tube and to detect bubbles in the fluid; and—an electrically grounded Electro-Magnetic Interference (EMI) shielding arranged between at least a part of the sensor assembly and the cavity such that the EMI shielding protects the sensor assembly from unwanted EMI emanating from a tube received within the cavity, which might otherwise cause the fluid flow sensing and bubble detecting apparatus to generate false bubble detection signals.