Pipetting Valve Bypass Channel Dampens Pump Pulsations

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Solution Overview

Problem

Existing pipetting devices struggle with precise dosing, especially with small-volume pipettes, due to pulsations from pump throttling and limited variability in pressure settings, making it difficult to maintain exact volume and requiring careful operator adjustments.

Innovation Solution

A pipetting device with a valve arrangement that includes a bypass channel connected to the environment, allowing for adjustable flow resistances in both the pipetting and bypass channels, which dampens pressure fluctuations and enables precise control of pipetting pressure independent of container size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the pump output is throttled to achieve precise dosing, then the volume flow is limited, but the pump pulsations continue into the pipette causing intermittent dosing and making exact volume maintenance difficult

Engineering Contradiction:
Improvedosing precisionVSAvoidvolume consistency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A bypass channel is introduced as an intermediary element between the pump chamber and the environment. This bypass channel provides an alternative flow path that absorbs pump pulsations before they reach the pipette, thereby maintaining dosing precision while eliminating volume inconsistency caused by pump throttling.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If throttle elements are added to limit volume flow in pressure lines, then dosing precision can be improved, but the system becomes severely limited in terms of variability and requires careful operator adjustments

Engineering Contradiction:
Improvedosing precisionVSAvoidsetting variability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The bypass channel serves multiple functions simultaneously: it limits volume flow for precise dosing, absorbs pump pulsations to ensure volume consistency, and provides adaptability for different pipetting scenarios without requiring separate throttle adjustments. This multi-functional design eliminates the need for operator adjustments while maintaining dosing precision across various conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Quantity of substance

If the pump power is reduced for small-volume pipettes, then the risk of overflow is reduced, but the pump pulsations have a stronger relative effect making precise metering difficult

Engineering Contradiction:
Improvepipette volumeVSAvoidmetering precision
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The bypass channel acts as a mediator that dampens pump pulsations before they affect the pipette filling process. When pump power is reduced for small-volume pipettes, the bypass channel absorbs the relatively stronger pump pulsations, preventing them from causing metering errors while still allowing precise control of the small volume being transferred.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This solution allows for precise metering of pipetting volume, reducing pump pressure pulsations and enabling accurate filling of small containers, even at low pump power, with adjustable settings for optimal pipetting performance.

Implementation Method 1

allowing for adjustable flow resistances in both the pipetting and bypass channels, which dampens pressure fluctuations

Methodology Applied
Scientific EffectPressure fluctuation damping: Damping

Data Source

PatentEP2633914B2Pipetting device and method for its production
Publication Date: 2020.04.08 EPPENDORF AG
  • EP2633914B2 patent drawingFigure 1
  • EP2633914B2 patent drawingFigure 2a~2c
  • EP2633914B2 patent drawingFigure 2d~2e

AI summary

The pipetting device has valve arrangement (200) with valve device (101") for adjusting a pipetting pressure. The valve device has valve chamber with pump unit which is connected with the valve chamber for producing a chamber pressure in the valve chamber. A pipette and bypass channel (104") which is opened to environment are respectively connected to the valve chamber. The valve device is formed such that it is distributed to produce the desired pipetting pressure in the pipette and the chamber pressure on the pipette and the bypass channel. An independent claim is included for method for manufacturing pipetting device.