Pipette Calibration via Adjustable Lower Stop Body

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Solution Overview

Problem

Existing pipettes require complex factory calibration and have accuracy issues due to manufacturing tolerances and wear, making user calibration difficult and costly.

Innovation Solution

A simplified pipette design with a displaceable screw element and overtravel spring allows for independent user calibration, reducing components and production costs while improving calibration accuracy by adjusting the lower stop body's position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If factory calibration is performed under standard conditions, then initial pipetting accuracy is achieved, but the pipette cannot be easily recalibrated for different liquid properties or environmental conditions

Engineering Contradiction:
Improvepipetting accuracyVSAvoidadaptability to different conditions
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The lower stop body is made adjustable rather than fixed, allowing the pipette to adapt to different liquid properties and environmental conditions. The user can modify the stroke volume by repositioning the lower stop body along the lifting rod, transforming a static calibration system into a dynamic one that responds to varying operational requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pipette enables users to perform their own calibration without requiring factory service or specialized equipment. The simple adjustment mechanism allows end-users to recalibrate the device themselves for different liquids or conditions, making the system self-sufficient and reducing dependency on external calibration services.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If the lower stop body is made adjustable for user calibration, then calibration accuracy for different conditions is improved, but the device complexity increases

Engineering Contradiction:
Improvecalibration accuracyVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The calibration adjustment function is segmented into a simple, isolated mechanism: the lower stop body can be independently repositioned along the lifting rod. This segmentation allows the adjustment feature to be added without complicating the overall pipette structure, as the modification is localized to a specific component rather than requiring system-wide changes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the physical parameter of the lower stop body's position along the lifting rod to achieve calibration adjustment. By varying this single parameter (position), the system adapts to different conditions without introducing complex mechanical, electronic, or control systems, thereby maintaining structural simplicity while improving calibration accuracy.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple components are used for calibration adjustment, then calibration functionality is achieved, but production costs increase

Engineering Contradiction:
Improvecalibration capabilityVSAvoidproduction cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The calibration adjustment function is merged into the existing lower stop body component rather than being implemented as a separate adjustment mechanism. The lower stop body itself serves dual purposes: limiting the lifting rod's stroke and providing the calibration adjustment point. This merging eliminates the need for additional adjustment components, reducing part count and production costs while maintaining calibration capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The lower stop body is designed with multi-functionality: it acts as both the stroke limit for the lifting rod and the adjustable calibration point for different conditions. This universal design allows a single component to fulfill multiple roles, reducing the total number of parts needed and simplifying the manufacturing process while providing comprehensive calibration functionality.

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

Enables accurate user calibration without factory settings, reducing production costs and improving pipette precision by allowing for adjustments based on liquid properties and environmental conditions.

Implementation Method 1

a lower stop body (27) which is adjustable for user calibration, an overtravel spring (31), via which the lower stop body (27) is supported on an overtravel spring bearing (32) against displacement downwards

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2633915B1Pipette with calibration system
Publication Date: 2016.09.21 EPPENDORF AG
  • EP2633915B1 patent drawingFigure 1
  • EP2633915B1 patent drawingFigure 2
  • EP2633915B1 patent drawingFigure 3

AI summary

The pipette (1) has a rod-shaped housing and a seat (50) for detachable holding of a pipette tip (51) at lower end of the housing, where a displacement unit is provided with a discharge chamber (57) with a movable boundary (58). A connecting channel (56) is provided to connect the displacement chamber with an opening in the seat. A drive unit is provided for displacing the displaceable boundary of the displacement chamber. The drive unit has an axially displaceable lifting rod (6) and is coupled with the displaceable boundary.