Drip Dispensing Head Layout to Prevent Foam at the Membrane
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Solution Overview
Problem
The existing packaging solutions for ophthalmic and cosmetic liquids with surfactant properties face challenges in drop-by-drop distribution due to foam formation at the outlet of the porous pad, disrupting the operation of the hydrophilic/hydrophobic bifunctional membrane, especially when a two-phase liquid/gas mixture comes into contact with it.
Innovation Solution
The dispensing head is designed with a hollow body insert containing a porous pad, where the pad is positioned downstream of the reservoir and upstream of the bifunctional membrane, and the base of the insert has radial air passages and a central pellet to guide air radially towards the bottle periphery, avoiding air retention and foam formation by ensuring air bubbles burst before reaching the membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a porous pad is used to regulate liquid flow in the dispensing head, then liquid flow control is improved, but foam forms at the outlet of the porous pad when liquid contains surfactant properties, disrupting membrane operation
Solution Approach 1:
The dispensing head is segmented into distinct functional zones: a first chamber for liquid entry, a second chamber for foam elimination, and a third chamber for membrane filtration. This segmentation separates the liquid flow regulation function from the foam elimination function, allowing each zone to perform its specific task effectively without interference.
Solution Approach 2:
The second chamber acts as an intermediary zone between the porous pad outlet and the bifunctional membrane. This intermediate chamber provides a transition space where air bubbles can escape and foam can be eliminated before the liquid reaches the membrane, preventing direct contact between foam and the membrane surface.
2Object-generated harmful factors
If air passages are added to guide air radially towards the bottle periphery, then air retention and foam formation are reduced, but the insert structure becomes more complex
Solution Approach 1:
The insert base is designed with localized air passages at specific positions to guide air radially towards the bottle periphery. Rather than redesigning the entire insert structure, air passages are added only where needed at the base level to achieve radial air flow, minimizing structural complexity while effectively reducing air retention.
3Productivity
If the porous pad is positioned upstream of the bifunctional membrane, then liquid flow regulation is improved, but air bubbles trapped in the pad cause foam formation when liquid passes through
Solution Approach 1:
The second chamber is positioned between the porous pad and the bifunctional membrane to perform preliminary foam elimination before liquid reaches the membrane. This preliminary action removes air bubbles and foam formed at the porous pad outlet in advance, ensuring that only air-free liquid contacts the membrane during subsequent filtration.
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 ensures reproducible drop volume and composition, maintaining the purity and accuracy of the dispensed liquid, even with surfactant formulations, by preventing foam formation and ensuring air-free liquid delivery, thus adhering to prescribed administration doses.
Implementation Method 1
a reservoir (2) having a wall with elastically reversible deformation and a liquid dispensing head via a dropper tip
Implementation Method 2
by suction of air towards the inside of the bottle after delivery of a dose of liquid
Implementation Method 3
a bifunctional membrane, partially hydrophilic and partially hydrophobic, of the type that is known to be made, for example, of polymer based on polyether sulfone
Implementation Method 4
according to a pressure differential between the pressure existing on the side of the diaphragm oriented towards the tank and the existing pressure on the opposite side of the diaphragm oriented towards the distribution channel
Implementation Method 5
a hollow-body insert containing a porous pad (more precisely microporous) which acts as a regulator of the flow of liquid
Data Source
Figure 1~1A
Figure 2~3
AI summary
The invention relates to a vial for packaging a liquid to be dispensed as a drip including a vessel having a deforming wall that can be elastically reversed by means of intake of air into the vessel, with a liquid-dispensing head mounted thereon, comprising a dropper tip projecting from the vial and an anti-bacterial filtering membrane, made to be partially hydrophilic and partially hydrophobic, which is placed across the flow of liquid and air, at the base of said dropper tip. The dispensing head comprises a hollow-body insert containing a porous pad regulating the liquid flow placed downstream from the vessel and upstream from a chamber defined downstream by said membrane. At the base of said insert on the inside of the vial, longitudinal arches supporting a central pad arrange a star formation of passages radially guiding the air that enters the vial after having passed through the porous pad.