Thermogeling Capsule Drying Temperature Control
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Solution Overview
Problem
Existing apparatus for manufacturing hard shell capsules from gelatin faces challenges when adapted to use thermogeling materials like HPMC, as rapid cooling causes phase transition back to a liquid state, resulting in poor quality or incomplete capsule components.
Innovation Solution
Preheating molds above the gelation temperature of thermogeling materials and maintaining a drying station at 50-90°C with 20-90% relative humidity to prevent cooling and ensure proper gelation, with optional wet bulb temperatures of 35°C or more, and adjusting temperature and humidity in multiple sections to control drying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If molds are cooled quickly to remove capsule material, then productivity increases, but the capsule material undergoes phase transition from gel state back to liquid state causing poor quality or incomplete components
Solution Approach 1:
The invention changes the temperature parameter from cooling to heating/maintaining in the drying station. The drying station maintains temperatures above the gelation temperature (typically 40-60°C) to keep the thermogeling material in gel state during drying, preventing phase transition to liquid state while still achieving adequate drying rates through controlled humidity and temperature parameters.
Solution Approach 2:
The invention exploits the phase transition properties of thermogeling materials by maintaining them above their gelation temperature during the drying process. This ensures the material remains in the desired gel phase rather than transitioning to liquid phase, which would occur with rapid cooling. The controlled thermal environment manages the phase state throughout the drying process.
2Manufacturing precision
If high temperature is maintained to prevent cooling below gelation temperature, then capsule component quality is maintained, but the molded components dry too quickly causing high stresses and strains leading to cracks or splits
Solution Approach 1:
The invention uses multiple drying parameters (temperature, relative humidity, air flow) in combination rather than relying solely on high temperature. The drying station employs controlled relative humidity (typically 20-70%) and moderate temperatures (40-60°C) to achieve balanced drying that prevents both overheating and rapid surface drying, thereby avoiding cracks and splits while maintaining component quality.
Solution Approach 2:
The invention introduces humidity control as an intermediary parameter between temperature and drying rate. By controlling the relative humidity in the drying station, the invention mediates the drying process to prevent too-rapid moisture removal that would cause surface cracking, while still maintaining temperatures sufficient to prevent gel-to-liquid phase transition.
3Device complexity
If conventional gelatin molding apparatus is used without modification, then device complexity is minimized, but it cannot properly process thermogeling materials due to incompatible temperature requirements
Solution Approach 1:
The invention changes the fundamental temperature parameter paradigm from gelatin-based cooling gelation to thermogeling-based heating gelation. The molding apparatus is adapted to heat molds above the gelation temperature of thermogeling materials during the molding process, then maintains appropriate temperature and humidity conditions during drying. This parameter change enables the use of thermogeling materials while requiring modifications to temperature control systems.
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 process ensures the production of high-quality hard shell capsule components by maintaining the thermogeling materials in a gelled state during drying, reducing the risk of cracking and splitting, and achieving uniform dimensions.
Implementation Method 1
the capsule components are formed from a material which undergoes gelation upon heating
Implementation Method 2
The molds are then transported through a series of drying ovens or kilns to remove the solvent (typically water or a water/alcohol mixture) and form the hardened capsule components on the molds
Data Source
AI summary
A method and apparatus for forming hard shell capsule components, wherein the capsule components are formed from a material which undergoes gelation upon heating, such as HPMC. A heat station is provided to heat a plurality of molds prior to dipping into a solution of the thermogeling material. The drying conditions following dipping are carefully controlled to control the rate of drying.