Aspiration Probe Pneumatic Stripping Mechanism
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Solution Overview
Problem
Existing automated instruments for aspirating liquids from sealed containers face issues with excessive weight due to high frictional forces between the aspiration probe and the rubber stopper, requiring heavy components to manage stripping, and complex mechanisms that can be prone to misalignment and malfunction.
Innovation Solution
A simplified apparatus using a support frame with dual drive motors and a shared linear drive member for both positioning and aspirating, combined with a tube detector/stripper member that applies a holding force to maintain alignment and reduce friction, allowing the aspiration probe to puncture and withdraw without heavy weights, and incorporating a probe-washing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heavy weighted plate is used to apply stripping force to the tube stopper, then the stripping function operates reliably, but the instrument weight increases considerably
Solution Approach 1:
The patent replaces the mechanical weighted plate system with a pneumatic system. A pneumatic cylinder applies controlled stripping force to the stopper without requiring heavy weights, eliminating friction-related reliability issues while significantly reducing the overall instrument weight.
Solution Approach 2:
The invention introduces pneumatic cylinders to provide the stripping force previously achieved only by heavy mechanical weights. The pneumatic system delivers reliable, controlled force application to separate the probe from the stopper without the drawbacks of mechanical friction and excessive weight.
2Reliability
If a complex mechanism with multiple independent components is used to achieve stripping and positioning, then the stripping function can be achieved, but the device complexity increases and misalignment risk rises
Solution Approach 1:
The patent combines multiple functions into integrated components. The support structure simultaneously provides mechanical support, positioning, and stripping force application. The pneumatic system is integrated with the probe assembly, eliminating the need for separate weighted plates and reducing the number of independent components that could misalign.
Solution Approach 2:
The pneumatic cylinder serves multiple functions: it positions the probe, applies stripping force, and maintains sealing pressure. This multi-functional component replaces several separate mechanisms, reducing overall device complexity while maintaining reliable operation.
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 apparatus is lighter in weight, requires fewer components, and simplifies the mechanism, reducing the risk of misalignment and malfunction while effectively aspirating liquids from sealed containers with reduced frictional forces, enhancing operational efficiency.
Implementation Method 1
apparatus for aspirating a volume of liquid contained in a sealed container
Implementation Method 2
the friction between the external surface of the probe and the rubber stopper can easily exceed 10-12 pounds
Data Source
AI summary
Apparatus for aspirating liquid from a container, e.g., a test tube, having a puncturable stopper includes a pair of stepper motors that share a common linear actuator or drive member. One motor operates to axially advance the linear drive member (preferably a lead screw) to a position in which it serves to position a rigidly connected tube-detector/stripper member in engagement with the top of a stopper on a tube. Thereafter, the second motor operates to move along the surface of the same drive member to advance an aspiration probe through the engaged stopper and into a liquid aspirating position within the tube. Preferably, a linear guide rail, slidably-mounted on a frame that supports the liquid-aspirating apparatus, serves to guide both the movement of the aspiration probe and the linear drive member. As a result of the shared components, the apparatus is highly precise and reliable.