Nested Piston Syringe Structure for Sequential Mixing Reliability

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Solution Overview

Problem

Existing multi-chamber syringes face issues with gas leakage, unreliable valve operation, and inefficient fluid mixing due to the use of single molded parts, which affect their reliability and effectiveness in sequential delivery and mixing applications.

Innovation Solution

The invention employs nested pistons, where two free pistons are coupled within a syringe barrel to form a fluid-tight apparatus with specific valve configurations, allowing for selective actuation and separation of chambers, including sterilizing filters, to achieve sequential delivery and mixing without gas contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single molded part is used for the valve piston, then manufacturing complexity is reduced, but gas leakage occurs and valve operation reliability deteriorates

Engineering Contradiction:

Improvevalve piston manufacturingVSAvoidvalve operation reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The valve piston is divided into multiple separate components: a piston body and a valve element. This segmentation allows each component to be optimized independently for its specific function, improving sealing performance and preventing gas leakage while maintaining manufacturing feasibility through modular assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The valve element is nested within the piston body structure, with the valve element positioned inside a cavity of the piston body. This nested configuration allows the valve to be integrated into the piston assembly while maintaining distinct functional zones, thereby improving reliability without significantly increasing overall complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Device complexity

If conventional single-chamber syringes are used, then device simplicity is maintained, but sequential delivery and mixing functionality cannot be achieved

Engineering Contradiction:

Improvesyringe structureVSAvoidsequential delivery and mixing capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The syringe is divided into multiple functional chambers separated by valve pistons. Each chamber can hold different substances and be controlled independently, enabling sequential delivery and mixing functions while maintaining a relatively simple overall syringe structure based on conventional designs.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The valve pistons incorporate dynamic valve elements that can transition between open and closed states based on pressure differentials and operational requirements. This dynamic behavior enables the syringe to switch between different delivery modes (sequential delivery, mixing, flushing) without requiring complex mechanical actuation systems.

Inventive Principle:

Principle #15Dynamics

3Productivity

If a one-way slit valve is used for mixing, then mixing functionality is achieved, but premature mixing occurs due to inadvertent forward displacement

Engineering Contradiction:

Improvemixing efficiencyVSAvoidpremature mixing prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The valve element design incorporates pressure feedback mechanisms where the valve responds to pressure differentials across the piston. The valve remains closed unless a sufficient pressure gradient is established in the correct direction, providing inherent protection against premature mixing while enabling efficient mixing when properly actuated.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The valve element has asymmetric geometry with different sealing characteristics for forward and reverse flow directions. This local quality differentiation ensures that the valve is more resistant to opening in the forward direction (preventing premature mixing) while allowing controlled opening when reverse pressure is applied for intentional mixing.

Inventive Principle:

Principle #3Local quality

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 nested piston design ensures reliable, sequential dispensing and mixing of fluids, maintaining chamber separation until actuated, and provides a conventional syringe with enhanced functionality for sequential delivery, mixing, and sterilization.

Implementation Method 1

When the nested piston apparatus is disposed in the barrel, with the first valve open and the second valve closed, a pressure differential can be applied across the nested piston apparatus to open the first valve and to close the second valve

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

a dome-shaped slit valve which is activated to an open state by an increased pressure gradient across the valve

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS20260000838A1Multi-chamber mixing syringe

Publication Date: 2026.01.01 THORNE INTELLECTUAL PROPERTY HOLDINGS LLC

AI summary

Nested piston apparatus is disclosed for making free pistons used to provide multi-chamber mixing and sequential delivery syringes within conventional syringe barrels. Each such syringe comprising one or more free pistons made according to the instant invention whereby syringe contents are selectively kept disparate until acted upon by forced displacement of an associated plunger rod. As well, nested piston apparatus is disclosed for using nested piston apparatus as multiple free pistons for making triple chamber syringes.