Cartridge Well Step Portion Prevents Overflow

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Solution Overview

Problem

Conventional cartridges for measuring fluids in immunoreaction experiments face challenges in preventing overflow and ensuring accurate sample quantity, as users may misidentify scale marks, leading to biohazard exposure and sample adherence issues.

Innovation Solution

A cartridge design featuring a recessed well with a step portion on its inner wall surface, including a planar portion and a rising wall surface, which serves as visual markers for the required fluid amount, preventing overflow and allowing easy production without undercuts, thus ensuring accurate sample measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If highly visible scale marks are formed on the inner wall surface of a well, then visual identification of the required sample amount is improved, but undercuts must be made during injection molding which makes it difficult to produce wells

Engineering Contradiction:
Improvevisual identification of sample amountVSAvoidproduction of wells
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of forming protruding scale marks that require undercut removal during molding, the patent forms recessed step portions on the inner wall surface of the well. This inverted approach eliminates the need for complex undercut removal processes while providing clear visual indicators for the required sample amount. The step portions are formed directly during injection molding without requiring additional machining or post-processing steps.

Inventive Principle:
Principle #13The other way round (Inversion)

2Measurement precision

If highly visible scale marks are formed on the inner wall surface of a well, then visual identification of the required sample amount is improved, but an injected sample may adhere to the scale marks with the result that a sample in an amount required for measurement cannot be taken

Engineering Contradiction:
Improvevisual identification of sample amountVSAvoidsample amount available for measurement
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent inverts the conventional approach by forming recessed step portions instead of protruding scale marks. This ensures that the sample fluid flows over the step portions without adhering to them, as the recessed structure allows gravity to pull the sample downward continuously. The step portions serve as visual indicators while preventing sample retention, ensuring the full required amount of sample is available for measurement.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The step portions are designed with specific local characteristics: they have a predetermined width and height, and are positioned at specific locations on the inner wall surface. The local geometry of the step portions (with smooth transitions and appropriate dimensions) ensures they provide visual indication without creating surfaces that would cause sample adhesion. This localized structural modification achieves both visual guidance and sample flow maintenance.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If scale marks are disposed on the inner wall surface of a well, then the user can visually recognize the amount of an injected sample, but the user may misidentify the scale marks leading to overflow and biohazard exposure

Engineering Contradiction:
Improvevisual recognition of sample amountVSAvoidprevention of overflow
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

By inverting the scale mark design from protruding to recessed step portions, the patent creates unambiguous visual indicators that are difficult to misinterpret. The recessed steps create clear meniscus formation and visible fluid level changes that are easily distinguishable, reducing the risk of misidentification. Additionally, the step portions physically guide the sample flow, providing both visual and tactile feedback to prevent overflow.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3722814B1cartridge
Publication Date: 2024.03.20 OTSUKA PHARM CO LTD
  • EP3722814B1 patent drawingFigure 1
  • EP3722814B1 patent drawingFigure 2
  • EP3722814B1 patent drawingFigure 3~3(c)

AI summary

[Problem] To ensure that a fluid is prevented from overflowing from a well and exposing the user to a biohazard. [Solution] A cartridge for use in measuring a component to be measured contained in a fluid includes a recessed well, formed for storing the fluid, the well including: a lower barrel portion that defines a lower space having a closed bottom; and an upper barrel portion that is formed above the lower barrel portion and defines an upper space having an opening on the top end, wherein a step portion is formed between the lower barrel portion and the upper barrel portion, the step portion being formed on an inner wall surface of the well and defining a step that continuously connects the inner wall surface of the lower barrel portion and the inner wall surface of the upper barrel portion.