Medical Adhesive Applicator Pneumatic Control
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Solution Overview
Problem
Current medical adhesive applicators, such as the DERMABOND® system, face issues with glass shard contamination, difficult adhesive flow control, and adhesive polymerization due to permeation in plastic containers, leading to inconsistent dispensing and short shelf life, especially for cyanoacrylate adhesives.
Innovation Solution
A squeeze tube is added to the conventional frangible glass vial applicator design to apply pneumatic pressure for controlled adhesive dispensing, and a dual chamber applicator with fluorinated plastic is used to prevent permeation and extend shelf life, allowing for easy and precise dispensing of medical adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frangible glass vial is used to hold adhesive, then the adhesive can be contained and protected, but glass shards are created that can contaminate the adhesive and impede flow
Solution Approach 1:
The harmful glass shards are extracted and separated from the adhesive containment system. The frangible glass vial is replaced with a plastic enclosure that does not generate contaminating shards when broken, eliminating the source of contamination while maintaining the containment function.
Solution Approach 2:
The frangible glass vial is replaced with a disposable plastic enclosure that is designed to be broken and discarded after single use. This eliminates the need for cleaning and reuse, preventing glass shard contamination while maintaining effective adhesive containment during the product's lifecycle.
2Productivity
If repetitive squeezing of the plastic enclosure is used to push adhesive through the porous plug, then adhesive flow is achieved, but the flow rate is difficult to control and adhesive comes out slowly or in spurts
Solution Approach 1:
Manual repetitive squeezing is replaced with a squeeze bulb pneumatic system that delivers controlled, consistent pressure to the adhesive. The squeeze bulb allows the operator to control adhesive flow rate through smooth, continuous pressure application rather than repetitive mechanical squeezing, eliminating spurts and improving flow consistency.
Solution Approach 2:
The mechanical squeezing action is transformed into pneumatic pressure application. By changing from direct mechanical compression to pneumatic pressure through a squeeze bulb, the system achieves smoother, more controllable adhesive flow with consistent pressure delivery.
3Productivity
If the plastic enclosure is vigorously pressed to increase adhesive flow rate, then faster dispensing is achieved, but bubbles are introduced into the adhesive
Solution Approach 1:
Vigorous pressing is replaced with controlled pneumatic pressure from a squeeze bulb. The pneumatic system delivers increased pressure smoothly and continuously, achieving faster adhesive flow rates without the sudden pressure spikes and air entrapment that cause bubbling during vigorous manual pressing.
Solution Approach 2:
The pressure application method changes from mechanical pressing to pneumatic compression. This parameter change allows for higher pressure delivery that maintains adhesive flow speed while avoiding bubble introduction through smooth, controlled pressure progression.
4Reliability
If conventional plastic enclosures are used to hold cyanoacrylate adhesive, then the adhesive can be contained, but the adhesive polymerizes due to permeation and container wall attack
Solution Approach 1:
The plastic enclosure material is enhanced with fluorinated coating or composite construction that provides barrier properties against cyanoacrylate permeation and chemical attack. This composite approach maintains the containment benefits of plastic while adding protection against polymerization, extending shelf life.
Solution Approach 2:
The plastic enclosure is treated to create an inert barrier environment that prevents cyanoacrylate adhesive from interacting with the container walls. The fluorinated surface or composite structure creates a chemically inert interface that stops polymerization reactions, extending the adhesive's usable shelf life.
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 modified applicators enable easy, controlled, and consistent dispensing of medical adhesives with reduced risk of glass shard contamination and extended shelf life, providing precise control and improved safety for medical use.
Implementation Method 1
presses on the DERMABOND® plastic enclosure with enough strength to break the frangible glass vial 14
Implementation Method 2
adhesive slowly flows out of the cracked vial through capillary action and onto the porous plug 18 of the applicator tip
Implementation Method 3
A squeeze tube is added to the conventional frangible glass vial applicator design to apply pneumatic pressure for controlled adhesive dispensing
Implementation Method 4
a dual chamber applicator with fluorinated plastic is used to prevent permeation and extend shelf life
Data Source
AI summary
Medical adhesive applicators are disclosed which allow medical adhesives to have long storage life and be easily dispensed in a controlled manner. In one embodiment, the applicator has a frangible glass vial with the medical adhesive. The frangible glass vial is held in a plastic enclosure with a dispensing tip. Attached to the plastic enclosure is a squeeze tube capable of imparting air pressure into the enclosure. To dispense medical adhesive quickly and with precision, one simply breaks the frangible glass vial and pushes on the squeeze tube. In another embodiment, the applicator has a proximal chamber containing medical adhesive, a distal chamber for dispensing medical adhesive and one or more rupturable membranes between them. To achieve long shelf life, the applicator chambers and membrane(s) are formed from fluorinated plastic. To dispense medical adhesive, one ruptures the membrane(s) and pushes on the sides of the proximal chamber.