Pressure Vessel with PEG Liquid Phase for CO2 Propellant
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Solution Overview
Problem
Existing pressure containers with separate chambers for propellants and materials face challenges in maintaining efficient pressure distribution and temperature stability, particularly when using carbon dioxide as a propellant, which affects the performance and efficiency of the pressure vessel.
Innovation Solution
A pressure vessel design featuring a gas phase comprising carbon dioxide and a liquid phase with polyethylene glycols and their monoethers or diethers, where the polyethylene glycol's molecular weight is selected based on ambient temperature, ensuring a high carbon dioxide content and optimal pressure regulation, with a separating part that varies the volume ratio between the storage and propellant chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon dioxide is used as a propellant in conventional pressure vessels, then the propellant can effectively pressurize the storage chamber, but the pressure changes significantly with temperature variations
Solution Approach 1:
The patent changes the physical state parameter of carbon dioxide from purely gaseous to a liquid-gas two-phase system by introducing a liquid phase (water or alcohol) that absorbs CO2. This parameter change stabilizes pressure across temperature variations because the liquid phase acts as a buffer, absorbing excess CO2 at higher temperatures and releasing it at lower temperatures, thereby maintaining reliable pressure in the storage chamber.
Solution Approach 2:
The patent introduces an intermediary substance (liquid phase of water or alcohol) between the gaseous CO2 and the stored material. This intermediary absorbs CO2 to form a liquid solution, mediating the pressure transmission to the storage chamber. The intermediary's ability to dissolve and release CO2 based on temperature changes provides stable pressure control, resolving the contradiction between pressure effectiveness and temperature sensitivity.
2Adaptability or versatility
If a two-chamber design with a separating part is used, then the propellant can be separated from the stored material, but the device complexity increases
Solution Approach 1:
The patent employs a flexible separating part (membrane or bladder) that can deform and move within the pressure vessel. This flexible shell separates the propellant chamber from the storage chamber while allowing volume adjustments as material is dispensed. The flexibility enables the separator to adapt to changing pressure and volume conditions without requiring complex mechanical structures, thus achieving spatial orientation dispensing capability with minimal added complexity.
Solution Approach 2:
The separating part is designed to be dynamic rather than static, allowing it to move and change shape as the propellant expands and contracts with temperature variations and as material is dispensed. This dynamic behavior enables the system to maintain proper pressure distribution and separation functionality across different operating conditions, providing adaptability for various dispensing orientations without requiring a complex fixed structure.
3Reliability
If the liquid phase contains polyethylene glycol, then the carbon dioxide solubility is optimized for pressure regulation, but the manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the molecular weight parameter of polyethylene glycol within a specific range (200-600 g/mol) to achieve optimal CO2 solubility and pressure regulation. By specifying this parameter range rather than a single precise value, the patent balances reliable pressure regulation with practical manufacturing considerations, allowing for normal distribution of molecular weights typical of PEG production processes while maintaining effective CO2 absorption and pressure control.
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 provides a pressure vessel with low temperature-dependent pressure changes, ensuring consistent performance and efficient use of carbon dioxide, maintaining the material under pressure effectively across varying temperatures.
Implementation Method 1
a liquid phase which comprises a compound selected from the polyethylene glycols and their (C 1 -C 4 ) monoethers and (C 1 -C 4 ) diethers and carbon dioxide dissolved therein
Implementation Method 2
the propellant presses from below onto a movable piston located in the container. This piston is typically initially located near the bottom of the container; the propellant is located in the cavity between the container base and the piston
Data Source
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AI summary
Disclosed are pressure vessels, especially an aerosol container, which comprise an interior that is subdivided into a storage chamber (3) and a propellant chamber (4) and are operated by means of a two-phase propellant. The gas phase (5) of the propellant encompasses carbon dioxide while the liquid phase (6) encompasses polyethylene glycol and/or a (C1-C4) monoether and/or a (C1-C4) diether of a polyethylene glycol, and carbon dioxide that is dissolved therein.