Hollow Needle Assembly With Offset Gas And Liquid Openings
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Solution Overview
Problem
Existing hollow needle assemblies for transfer devices face challenges in ensuring reliable ventilation of storage containers during liquid transfer, leading to potential blockages and unwanted liquid entrainment in the gas channel, which can result in clogged air filters and contamination.
Innovation Solution
The hollow needle assembly features separate and offset liquid and gas channel openings with sharp separating edges, preventing liquid transfer between channels and incorporating an annular space with an axial channel body to direct gas flow and separate liquid droplets, thereby reducing the risk of blockages and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If liquid and gas channels share a common opening area in the hollow needle, then the device structure is simplified, but liquid can enter the gas channel causing blockages and contamination
Solution Approach 1:
The common opening area is segmented into separate liquid channel opening and gas channel opening by introducing a separating edge. This divides the previously unified structure into distinct functional zones, preventing liquid from entering the gas channel while maintaining structural integration in the hollow needle.
Solution Approach 2:
A separating edge is introduced as an intermediary element between the liquid channel opening and gas channel opening. This separating edge acts as a barrier that prevents liquid from crossing into the gas channel, ensuring reliable ventilation while maintaining a compact design.
2Productivity
If the hollow needle has smooth internal surfaces to facilitate liquid flow, then liquid transfer efficiency is improved, but liquid droplets can be entrained in the gas channel
Solution Approach 1:
The separating edge, which initially might seem to create turbulence or flow resistance, actually converts the potential harm of liquid droplet entrainment into a benefit by acting as a flow separator. It allows liquid to flow efficiently through the liquid channel while preventing droplets from being carried into the gas channel.
3Manufacturing precision
If the hollow needle opening is positioned centrally to simplify manufacturing, then manufacturing precision is improved, but stopper components can be punched out during piercing
Solution Approach 1:
The opening structure is made asymmetric by offsetting the liquid channel opening and gas channel opening relative to the central axis. The liquid channel opening is positioned laterally offset while the gas channel opening remains more central, creating an asymmetric configuration that prevents stopper punching while maintaining manufacturing feasibility.
4Speed
If liquid channel openings are positioned closer to the needle tip to improve liquid ejection, then liquid transfer speed is improved, but liquid can overflow into the gas channel due to gravity
Solution Approach 1:
The problem of liquid overflow is solved by adding a circumferential dimension to the separation mechanism. Instead of relying solely on axial positioning, a separating edge extends in the circumferential direction to create a three-dimensional barrier that prevents liquid from crossing into the gas channel opening, even when liquid is ejected at high speed near the needle tip.
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 design effectively prevents liquid from entering the gas channel, reduces the likelihood of ventilation duct clogging, and ensures reliable ventilation of storage containers, maintaining the sterility of the air filter and preventing unwanted liquid escape.
Implementation Method 1
The separating edge can be designed with sharp edges. The result of this is that liquid escaping from the liquid channel opening is released from the hollow needle at the separating edge and thus does not get into the area of the gas channel opening.
Implementation Method 2
Furthermore, a disadvantageous overflow of liquid into the gas channel due to the effect of gravity during injection is reduced.
Data Source
Figure 1
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AI summary
A hollow-needle assembly is part of a transfer apparatus that serves for transferring a liquid between a storage container and a further use container. The hollow-needle assembly has a hollow needle having a pointed needle end. A liquid duct for transporting liquid through the hollow needle and out of the latter leads out via at least one liquid-duct opening in the region of the free needle end. An aeration gas duct that likewise leads out via a gas-duct opening in the region of the free needle end serves for transporting gas through the hollow-needle assembly. Duct paths of the at least one liquid duct and of the at least one aeration gas duct extend separately from one another. The ducts lead out adjacently to one another axially along the hollow needle and in a manner offset from one another in the circumferential direction. A needle separating edge that extends in the longitudinal direction of the hollow needle extends between in each case one liquid-duct opening and an adjacent gas-duct opening in the circumferential direction. This results in reliable ventilation and venting of the storage container via the hollow needle when liquid is transferred.