Modular Cryogenic Tunnel Freezer Without Internal Fans
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Solution Overview
Problem
Conventional cryogenic tunnel freezers are not cost-effective for small and mid-sized food processing operations due to high purchase and operating costs, as well as the need for large on-site liquid nitrogen storage and equipment, making them unsuitable for intermittent use.
Innovation Solution
A cryogenic freezer design featuring an upper and lower section with insulated members, a pervious belt for cryogenic fluid passage, and a drive assembly that allows the lower section to be lowered and raised, eliminating the need for internal air-moving devices and reducing insulation gaps, thus enhancing efficiency and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional cryogenic tunnel freezers with internal fans are used, then freezing speed is improved, but purchase and operating costs increase significantly
Solution Approach 1:
The patent removes the internal fan system from the tunnel freezer, extracting the air-moving function entirely. The freezer relies on natural convection and the belt movement to circulate cryogenic fluid, eliminating complex mechanical components while maintaining freezing effectiveness.
Solution Approach 2:
The system uses the product belt itself to facilitate fluid circulation rather than requiring separate air-moving devices. The belt movement through the tunnel creates natural convection currents that distribute the cryogenic fluid, making the system self-sufficient without additional active components.
2Stability of the object's composition
If conventional tunnel freezers with fixed sections are used, then structural stability is improved, but ease of maintenance and cleaning deteriorates
Solution Approach 1:
The tunnel freezer is divided into separate upper and lower sections that can be independently moved. The lower section can be lowered away from the upper section, allowing easy access to the belt and internal components for maintenance and cleaning while maintaining structural integrity during operation.
Solution Approach 2:
The lower section is made movable rather than fixed, allowing it to be lowered and raised as needed. This dynamic design enables easy access to internal components for maintenance while maintaining structural stability during the freezing operation when sections are connected.
3Strength
If conventional freezers with solid belts are used, then belt strength is improved, but thermal transfer efficiency deteriorates
Solution Approach 1:
The belt is designed with permeable or porous characteristics that allow cryogenic fluid to pass through it. This enables direct thermal contact between the fluid and products on both sides of the belt, significantly improving heat transfer efficiency while the belt maintains sufficient mechanical strength through its structural design.
4Reliability
If large on-site liquid nitrogen storage tanks are used, then cryogen supply reliability is improved, but investment cost and space requirements increase
Solution Approach 1:
The system is designed to operate efficiently with smaller amounts of cryogen by optimizing the freezing process. The permeable belt and improved fluid circulation allow effective freezing with reduced cryogen consumption, eliminating the need for large storage tanks while maintaining reliable operation for small to mid-sized operations.
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 design reduces operational costs, simplifies assembly and maintenance, and provides efficient cryogenic freezing without the need for internal fans, improving thermal transfer and reducing refrigeration losses, making it suitable for small and mid-sized food processing operations.
Implementation Method 1
exposing the food product to the cryogen within the tunnel
Implementation Method 2
the cryogen, such as liquid nitrogen (LIN), to cool and freeze food products
Implementation Method 3
the belt being pervious to liquid and vapor
Data Source
AI summary
A cryogenic tunnel freezer (10) having modular design and construction including a lower section (16) that can be raised and lowered relative to an upper section (14), the upper and lower sections (14, 16) defining a tunnel (12) when the lower section (16) is in a closed (raised) position. Product is moved through the tunnel (12) via a belt (22) formed of arrays of plastic modules (76) that are reinforced by metal chains (140) and rods (150). The lower run (23) of the belt (22) rides on the floor (48) of the lower section (16) and the upper run (21) rides on the lower run (23) when the belt (22) is operated. The flow of cryogenic fluid through the tunnel (12) is aided by vaporization of a cryogenic fluid and baffles (98), but no air-moving devices located within the tunnel (12).