Infusion Pump Magnetic Pressure Sensor Ambient Field Compensation

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Solution Overview

Problem

Magnetic pressure sensors in infusion pumps are susceptible to inaccuracy due to unintended ambient magnetic fields, leading to false occlusion alarms or missed occlusions, which can have serious safety consequences for patients.

Innovation Solution

Incorporating secondary Hall effect sensors to detect ambient magnetic fields and adjust primary sensor output signals to compensate for these influences, ensuring accurate fluid pressure measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnetic pressure sensors are used in infusion pumps, then the pump can detect tubing occlusions, but the sensors become susceptible to inaccuracy from ambient magnetic fields

Engineering Contradiction:

Improveocclusion detection accuracyVSAvoidambient magnetic field interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A ferromagnetic shield acts as an intermediary element positioned between the ambient magnetic field sources and the pressure sensing magnet. This shield redirects and contains the ambient magnetic field lines, preventing them from reaching the Hall effect sensor and causing false readings. The shield effectively mediates the interaction between the harmful external field and the sensitive sensor components.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a magnetically inert environment by enclosing the pressure sensing magnet and Hall effect sensor within a ferromagnetic shield. This shielded enclosure acts as a magnetically inert space that isolates the sensitive components from external magnetic field variations, allowing the sensor to operate accurately regardless of ambient magnetic conditions.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Measurement precision

If magnetic pressure sensors are used to monitor fluid pressure, then occlusions can be detected, but false occlusion alarms occur due to ambient magnetic field influence

Engineering Contradiction:

Improvefluid pressure measurement accuracyVSAvoidalarm accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The ferromagnetic shield serves as a protective intermediary that filters out ambient magnetic field variations before they can affect the pressure measurement. By blocking these external magnetic influences, the shield ensures that the Hall effect sensor only detects changes in magnetic field caused by tubing pressure variations, thereby improving measurement precision and reducing false alarms.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful ambient magnetic field into a beneficial shielding effect. By introducing the ferromagnetic shield, the system utilizes magnetic field redirection principles to protect the sensor. The same magnetic properties that could cause interference are harnessed to create a protective magnetic shield that enhances measurement reliability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If magnetic pressure sensors are incorporated into the infusion pump, then pressure monitoring is enabled, but the device complexity increases due to additional shielding components

Engineering Contradiction:

Improvepressure sensing capabilityVSAvoidsensor system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The ferromagnetic shield is integrated with existing pump housing structures or mounting brackets, combining the shielding function with structural support elements. This merging approach allows the shield to perform its magnetic protection function while also serving as part of the mechanical assembly, thereby minimizing the increase in overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The ferromagnetic shield components are designed to serve multiple functions: providing magnetic field shielding, acting as structural support, and potentially serving as mounting surfaces for other components. This multi-functionality reduces the need for separate dedicated shielding parts, thereby limiting the increase in device complexity while maintaining reliable pressure sensing.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution effectively mitigates the impact of ambient magnetic fields on pressure measurements, reducing false alarms and ensuring accurate detection of occlusions, thereby enhancing patient safety and infusion protocol reliability.

Implementation Method 1

a corresponding Hall effect sensor arranged to generate an output voltage signal proportional to the strength of the magnetic field of the magnet

Methodology Applied

Scientific EffectHall effect: Hall Effect

Implementation Method 2

at least one secondary Hall effect sensor arranged to detect an ambient magnetic field in the vicinity of the infusion pump capable of being detected by the primary Hall effect sensor

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS11077248B2Magnetic pressure sensing system for an infusion pump

Publication Date: 2021.08.03 ZEVEX INC

AI summary

An infusion pump having one or more magnetic pressure sensors for detecting tubing occlusions is provided with at least one corresponding secondary Hall effect sensor arranged to detect an ambient magnetic field influencing pressure measurements so that corrective action may be taken to mitigate the effects of the ambient magnetic field.