Powered Positive Displacement Pipette With Secure Syringe Ejection

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Solution Overview

Problem

Existing positive displacement pipettes struggle with accurate, non-contact dispensing of very small liquid volumes and have complex syringe installation, retention, and ejection mechanisms.

Innovation Solution

A handheld, powered positive displacement pipette with a motorized drive assembly, dispensing solenoid, syringe retention mechanism, and syringe piston grasping mechanism, allowing for secure syringe attachment, non-contact dispensing, and automatic ejection, with features like fluid viscosity detection and syringe identification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direct contact between piston and liquid is used in positive displacement pipettes, then accuracy is improved, but liquid adheres to pipette tip requiring touch-off contact

Engineering Contradiction:

Improvedispensing accuracyVSAvoidnon-contact dispensing capability

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The piston is extracted from direct contact with the liquid by introducing a syringe as an intermediate component. The syringe barrel contacts the liquid while the piston remains isolated, allowing accurate positive displacement control without liquid adhesion to the pipette tip.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The syringe acts as an intermediary between the piston and the liquid. It transmits the piston's reciprocating motion to the liquid while preventing direct contact, thereby eliminating liquid adhesion issues while maintaining positive displacement accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If disposable syringes are used in positive displacement pipettes, then piston reuse is prevented, but syringe insertion and ejection complexity increases

Engineering Contradiction:

Improvepiston contamination preventionVSAvoidsyringe retention and ejection mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The syringe is segmented into distinct components (barrel, piston, tip) that can be independently manipulated. The retention mechanism segments the ejection process into controlled steps, reducing overall complexity while ensuring reliable disposal of contaminated syringes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The syringe ejection mechanism is designed to automatically perform the ejection function without requiring complex manual operations. The system self-manages the retention and release of disposable syringes, reducing operational complexity while maintaining reliability.

Inventive Principle:

Principle #25Self-service

3Device complexity

If friction-based tip retention is used in air displacement pipettes, then simplicity is maintained, but secure retention of syringes in positive displacement pipettes is insufficient

Engineering Contradiction:

Improveretention mechanism simplicityVSAvoidsyringe retention security

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The retention mechanism merges multiple functions (mechanical retention, alignment, and locking) into a single integrated system. This combines the simplicity of friction-based retention with the security of positive locking, achieving both goals simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The retention mechanism performs preliminary alignment and positioning of the syringe before final engagement. This preliminary action ensures proper orientation and secure retention, reducing the need for complex adjustment mechanisms while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

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

Enables accurate and repeatable dispensing of sub-microliter volumes without user contact, simplifying syringe installation and ejection, and reducing operator error.

Implementation Method 1

a solenoid assembly that is coupled to the piston carrier and is operable to rapidly displace the piston carrier a predetermined distance in the distal direction

Methodology Applied

Scientific EffectSolenoid: Solenoid

Data Source

PatentEP4467239B1Powered positive displacement pipette

Publication Date: 2026.03.11 RAININ INSTRUMENT LLC

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Figure 3~4
Figure 5A~5B

AI summary

Described are exemplary embodiments of a handheld, powered positive displacement pipette assembly, including a plurality of syringes of different volumes and a powered positive displacement pipette having unique mechanisms for the retention, identification and ejection of said syringes. Described are further related syringes, related handheld powered positive displacement pipettes and related mechanisms. In particular, the claimed invention relates to a powered handheld positive displacement pipette (5) comprising a hollow body (10) for housing internal components of the pipette, a motorized drive assembly (40), a piston carriage (100) coupled to the motorized drive assembly, a syringe piston grasping mechanism (200), a syringe retention mechanism (150) including a plurality of syringe latching elements (155), a syringe ejection mechanism, and a dispensing solenoid assembly (250). The dispensing solenoid assembly resides within the piston carriage and is linearly displaceable relative thereto. The dispensing solenoid assembly includes a linearly displaceable armature (260) having a distally extending shaft (265). The syringe piston grasping mechanism is configured to be linearly reciprocatable by the dispensing solenoid assembly relative to the piston carriage and the pipette body (10).