Bulk Freeze Drying with Spray Freezing and Vibratory Shelves
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Solution Overview
Problem
Conventional freeze drying systems for bulk products face challenges in handling large masses, leading to agglomeration, irregular heat transfer, longer cycle times, and difficulty in maintaining aseptic conditions due to metal-to-metal contact, which complicates sterilization and results in product handling losses.
Innovation Solution
A nozzle system for a freeze drying system that generates uniform fluid product drops using a setpoint pressure, combined with a freezing vessel that forms frozen particles in a controlled freezing zone, and a drying chamber with sloped shelves and vibration elements to promote sublimation and prevent agglomeration, ensuring aseptic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bulk product is placed in trays for freeze drying, then the product can be processed in aseptic conditions, but heat transfer becomes irregular and cycle times increase
Solution Approach 1:
The bulk product is divided into individual particles through spray freezing, where each particle is frozen separately as it falls through the freezing zone. This segmentation eliminates the heat transfer problems associated with large mass blocks while maintaining aseptic processing, as each particle is independently treated and then collected in the drying chamber.
2Productivity
If bulk product is processed in large masses, then productivity increases, but agglomeration occurs and heat transfer becomes irregular
Solution Approach 1:
The system processes bulk product by segmenting it into individual droplets that are frozen separately. The spray nozzle breaks the bulk liquid into many small droplets that fall through the freezing zone independently, preventing agglomeration during freezing while maintaining high productivity through continuous processing.
Solution Approach 2:
The invention transitions from horizontal tray-based processing to vertical spray freezing. Bulk liquid is sprayed vertically downward through the freezing zone, allowing particles to freeze in free fall and then be conveyed vertically through the drying chamber, eliminating the heat transfer irregularities of horizontal tray processing.
3Strength
If metal-to-metal contact is used in the drying chamber, then structural integrity is maintained, but sterilization becomes difficult and aseptic conditions are compromised
Solution Approach 1:
The invention replaces mechanical metal-to-metal contact with a vibratory conveying system. Frozen particles are moved through the drying chamber by vibration of the chamber walls or internal surfaces, eliminating the need for metal rollers or belts that are difficult to sterilize. This maintains structural integrity while enabling effective sterilization.
4Ease of operation
If manual handling of trays is used, then product loading and unloading is simple, but handling losses occur and productivity decreases
Solution Approach 1:
The system eliminates manual tray handling by implementing automated spray freezing and vibratory conveying. Product is automatically sprayed, frozen, conveyed through drying, and collected without manual intervention, eliminating handling losses while maintaining ease of operation through automated batch processing.
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 system efficiently produces freeze-dried product in powder form while maintaining aseptic quality, reducing handling losses and cycle times, and ensuring uniform particle size and heat transfer efficiency.
Implementation Method 1
The nozzle is operated at a setpoint nozzle pressure to generate fluid product drops having a size suitable for freeze drying
Implementation Method 2
a cooling fluid flows through the cavity inlet, cavity and cavity outlet to form a freezing zone
Implementation Method 3
a cooling fluid flows through the cavity inlet, cavity and cavity outlet to form a freezing zone
Implementation Method 4
a heating element is associated with each shelf that heats the frozen particles to promote sublimation
Implementation Method 5
a plurality of vibration elements located outside the drying chamber vibrate the shelves in a horizontal direction to cause the frozen particles to advance relative to an associated shelf and move from shelf to shelf
Implementation Method 6
Both the freeze drying chamber and the condensing chamber are maintained under vacuum during the process by a vacuum pump
Data Source
AI summary
A freeze drying system having a nozzle operated at a setpoint pressure to generate fluid product drops for freezing in a freezing chamber of a freezing vessel. The freezing chamber includes an inner wall that defines a cavity and an outer wall having an inlet that extends from a location on the outer wall that is lower than an outlet. A cooling fluid flows through the inlet, cavity and outlet to form a freezing zone. A drying chamber having sloped shelves receives frozen particles from the freezing chamber. A heating element is associated with each shelf that heats the frozen particles to promote sublimation. Vibration elements located outside the drying chamber vibrate the shelves causing the frozen particles to move from shelf to shelf to form freeze dried product.