Infusion Pump Syringe Barrel Coating for Low-Flow Accuracy

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Solution Overview

Problem

Traditional off-the-shelf syringes used with infusion pumps suffer from performance limitations such as long start-up times, inconsistent flow profiles, delayed occlusion detection, and stick-slip behavior, particularly at low flow rates, leading to inaccuracies and safety issues.

Innovation Solution

The syringe design features a rigid plunger rod with reduced compliance, improved sealing, and a tribofilm coating to minimize deformation and friction, along with a robust plunger seal, enhancing flow constancy and reducing unintended bolus volumes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional off-the-shelf syringes are used with infusion pumps, then ease of operation is improved (off-the-shelf syringes can be used), but flow consistency deteriorates (stick-slip behavior, flow discretization)

Engineering Contradiction:

Improveease of useVSAvoidflow consistency

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The syringe barrel is coated with a low surface energy coating that changes the surface properties to reduce friction between the plunger rod and barrel. This parameter change in surface energy reduces stick-slip behavior and improves flow consistency while maintaining ease of use with off-the-shelf syringes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The coating is applied locally to the inner surface of the syringe barrel where friction occurs, rather than modifying the entire syringe structure. This localized improvement addresses flow consistency issues without affecting the overall ease of operation

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If traditional syringes are used with syringe pumps, then adaptability is improved (wide ranges of syringe brands and sizes can be accommodated), but manufacturing precision deteriorates (inaccurate flow delivery)

Engineering Contradiction:

Improvecompatibility with various syringe brandsVSAvoidflow delivery accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The low surface energy coating is applied to the inner barrel surface to universally reduce friction across different syringe brands and sizes. This universal coating approach maintains adaptability while improving flow delivery accuracy for all compatible syringes

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

By changing the surface energy parameter of the barrel through coating, the system achieves more consistent friction characteristics across different syringe manufacturers, thereby improving manufacturing precision of flow delivery while preserving versatility

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If traditional syringes are used in syringe pumps, then device complexity is reduced (no proprietary syringes needed), but reliability deteriorates (performance limitations at low flow rates)

Engineering Contradiction:

Improvesystem simplicityVSAvoidperformance at low flow rates

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The low surface energy coating changes the friction parameter in the syringe system, enabling traditional off-the-shelf syringes to perform reliably at low flow rates when used with syringe pumps, thereby maintaining system simplicity without sacrificing reliability

Inventive Principle:

Principle #35Parameter changes

4Ease of manufacture

If traditional syringes are used with infusion pumps, then ease of manufacture is improved (off-the-shelf syringes can be used), but loss of time increases (long start-up times)

Engineering Contradiction:

Improveuse of standard syringesVSAvoidstart-up time

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The low surface energy coating reduces friction between the plunger rod and barrel, which decreases the time required for the plunger to reach steady-state motion during start-up. This allows traditional syringes to be used while reducing start-up time losses

Inventive Principle:

Principle #35Parameter changes

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 improved syringe design achieves faster start-up times, reduced occlusion detection times, and minimized stick-slip behavior, ensuring accurate and consistent fluid delivery across varying conditions.

Implementation Method 1

a tribofilm coating to minimize deformation and friction

Methodology Applied

Scientific EffectTribofilm:

Implementation Method 2

rigid plunger rod with reduced compliance

Methodology Applied

Scientific EffectCompliance reduction:

Data Source

PatentUS20260091168A1Syringes for infusion pumps

Publication Date: 2026.04.02 ICU MEDICAL INC

AI summary

Embodiments of syringes and components thereof described herein provide reduced compliance from flexing or deformation, of not only the syringe barrel but also of the syringe plunger rod and plunger seal. Embodiments of syringes and components thereof described herein also provide improved sealing between the barrel and the syringe plunger rod, and improved resistance to pressure. Embodiments of syringes and components thereof described herein are advantageously suited for use with an infusion pump which may subject syringes to many start/stop operations over a period of hours, sometimes at very low flow rates.