Syringe Flow Disruptor for Foam Quality
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Solution Overview
Problem
Syringes used for dispensing injectable foams face issues such as air contamination, 'mushrooming' of foam, turbulent mixing, and pressure-induced plunger ejection, leading to inaccurate dosing and waste, especially in smaller syringes for treating superficial veins.
Innovation Solution
A syringe design featuring a flow disruptor within the injectate chamber to control foam flow, a vented waste chamber to purge air, and a pre-cracked configuration to minimize air contamination and ensure accurate dosing, with features like a duct with one-way valves and a frusto-conical plunger to aid smooth foam flow and retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If foam is produced from a pressurised canister and enters the syringe chamber, then the foam fills the chamber, but air becomes trapped and foam quality deteriorates due to turbulent mixing and mushrooming
Solution Approach 1:
A flow disruptor element is introduced as an intermediary component between the canister outlet and the syringe chamber. This flow disruptor breaks up the turbulent foam flow, preventing mushrooming and reducing air entrapment, thereby maintaining foam quality consistency during chamber filling
Solution Approach 2:
The system changes the flow parameters of the foam by using the flow disruptor to convert high-velocity turbulent flow into lower-velocity laminar flow. This parameter change prevents foam breakdown and maintains consistent foam quality while still allowing complete chamber filling
2Measurement precision
If the syringe plunger is pulled back to pre-fill the chamber with foam, then dosing accuracy improves, but air contamination increases requiring additional purging
Solution Approach 1:
The flow disruptor is positioned to act on foam flow during the preliminary filling stage, ensuring that even when the chamber is pre-filled by pulling back the plunger, the foam enters in a controlled manner that minimizes air entrapment, reducing subsequent purging requirements
3Productivity
If high pressure foam is used to fill the syringe quickly, then productivity increases, but the plunger may be ejected from the barrel causing waste
Solution Approach 1:
The flow disruptor serves as a pressure-regulating intermediary that dissipates the high pressure of the incoming foam through turbulence and flow redistribution. This allows rapid filling to maintain productivity while preventing plunger ejection by reducing peak pressure forces
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 syringe effectively minimizes air contamination and ensures consistent, high-quality foam delivery, reducing waste and improving dosing accuracy, even in smaller volumes, by controlling foam flow and purging air efficiently.
Implementation Method 1
Turbulent mixing of the foam is also observed as the chamber fills, such that foam can break down
Implementation Method 2
a vented waste chamber to purge air
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
Syringes which are suitable for dispensing and injecting medical foams for sclerotherapy are described and claimed. The syringes of the invention comprise a syringe barrel having a nozzle and a bore to receive a syringe plunger; a syringe plunger defined by a front end and a rear end connected by a tubular walls and having an internal hollow duct between the front end and the rear end, and through which foam can flow; and an injectate chamber formed by insertion of the front end of the plunger into the barrel. The syringes comprise a flow-disruptor arranged to modify the flow of foam as it enters the injectate chamber. In certain embodiments the syringes comprise waste chambers which capture and retain poor quality foam. The syringes are particularly useful for dispensing foams made with little or no nitrogen content and are configured to reduce the risk of air contamination during dispensing the foam. Kits comprising the syringes together with a suitable source of foam and methods of dispensing foam form further aspects of the invention.