Implantable Infusion Pump Propellant Mixtures for Stable Flow
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Solution Overview
Problem
Existing implantable infusion pumps using fluorocarbons face issues with non-therapeutic function at extreme temperatures and potential toxicity to the ozone layer, leading to flow rate inconsistencies and regulatory restrictions.
Innovation Solution
Implementing a fluorocarbon mixture or non-fluorocarbon substitutes with uniform expansion rates to maintain consistent flow rates across varying body temperatures and reduce environmental toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fluorocarbon propellant is used in the implantable infusion pump, then the device can operate with a simple structure, but the flow rate becomes non-therapeutic at temperatures outside normal patient ranges (fever or severe cold)
Solution Approach 1:
The patent applies composite materials by using a mixture of fluorocarbons with different boiling points and expansion characteristics. This composite propellant system maintains uniform expansion rate (+/- 3%) across a broader temperature range (85°F to 105°F) compared to single fluorocarbon, ensuring consistent flow rate during fever or cold exposure without requiring additional control mechanisms.
2Duration of action of stationary object
If fluorocarbon chemical power source is used to provide perpetual power, then battery replacement is eliminated, but the fluorocarbon releases toxic substances detrimental to the ozone layer when released into the atmosphere
Solution Approach 1:
The patent applies parameter changes by carefully selecting fluorocarbon mixtures with specific vapor pressure characteristics that match physiological conditions. The mixture is formulated to provide adequate expansion force for perpetual operation while having lower atmospheric persistence and reduced ozone depletion potential compared to traditional single fluorocarbons, thus reducing environmental harm while maintaining power duration.
3Device complexity
If the pump operates at fixed expansion rate, then the mechanical structure remains simple, but the flow rate varies significantly with body temperature changes (fever or chilling)
Solution Approach 1:
The patent applies phase transitions by utilizing the vaporization and expansion characteristics of a multi-component fluorocarbon mixture. As body temperature changes, different fluorocarbon components transition between liquid and vapor phases at different rates, compensating for temperature variations and maintaining uniform overall expansion rate. This natural phase behavior provides flow rate stability without requiring active control mechanisms.
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
Ensures therapeutic operation across a broad temperature range and minimizes environmental impact by stabilizing flow rates and reducing toxic emissions.
Implementation Method 1
a fluorocarbon mixture with an uniform rate of expansion (+/-3%) over a temperature range of from 85° F.-105° F.
Implementation Method 2
it is only temperature dependent. As the propellant expands to vapor it exerts ever-increasing pressure
Implementation Method 3
via the action of the reverse bellows mechanism, restricts the sealed outer/inferior chamber volume, thereby, reconstituting the fluorocarbon in the sealed chamber back into the smaller volume liquid phase from the vapor phase
Data Source
AI summary
The invention is an improved implantable infusion pump of the type having a sealed outer/inferior chamber holding a fluorocarbon, wherein the improvement(s) are replacing the fluorocarbon with a fluorocarbon mixture with an uniform rate of expansion (+/−3%) over a temperature range of from 85° F. to 105° F., or replacing the fluorocarbon with a different chemical exhibiting comparable vapor/liquid and expansion capability with a uniform rate of expansion (+/−3%), over a temperature range of from 85° F. to 105° F. One example of such a mixture for the first improvement is a binary n-decafluorobutane (Halocarbon 610 or refrigerant R 610) and n-perfluorohexane (Fluorinert FC-72) with a weight/weight ratio falling between 25/75 and 35/65. Three such examples of the second improvement are 2-methylbutane, 1-pentane, and a 50:50 mixture of the two.