High-precision control system and method for shipborne cryogenic flash freezing of aquatic product using liquid nitrogen
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Solution Overview
Problem
Conventional methods for preserving seafood on fishing ships, such as using ice with added preservatives like sodium metabisulfite, pose health risks and do not effectively maintain the quality and value of the catch, especially in open-sea operations where resources are dwindling.
Innovation Solution
A high-precision control system and method for shipborne cryogenic flash freezing using liquid nitrogen, which includes a main control system, display unit, liquid nitrogen supply system, valve control unit, and power unit, allowing for precise temperature control and preservative-free preservation of aquatic products through a four-stage freezing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If ice with preservatives is used for preservation, then preservation duration is extended, but food safety and product quality deteriorate due to carcinogenic substances
Solution Approach 1:
The patent changes the temperature parameter from conventional freezing (above -18°C) to ultra-low temperature cryogenic freezing (-30°C to -196°C using liquid nitrogen). This parameter change enables preservation without preservatives, as the extreme cold instantly freezes and preserves seafood, eliminating the need for harmful chemical additives while extending preservation duration
Solution Approach 2:
The patent utilizes the phase transition of liquid nitrogen from liquid to gas state during evaporation. This phase transition absorbs large amounts of heat, creating ultra-low temperature conditions that instantly freeze seafood and preserve it without requiring preservatives, thus resolving the contradiction between preservation duration and food safety
2Use of energy by moving object
If conventional freezing methods are used, then energy consumption is reduced, but protein denaturation and quality loss increase
Solution Approach 1:
The patent applies rapid flash freezing that skips the dangerous temperature zone where ice crystals form and damage muscle fibers. By instantly freezing seafood from -30°C to -196°C, the process rushes through the critical phase where conventional slow freezing causes protein denaturation and quality loss, achieving superior quality despite higher energy input
3Manufacturing precision
If liquid nitrogen flash freezing is implemented, then product quality and preservation level are improved, but system complexity and control difficulty increase
Solution Approach 1:
The patent segments the freezing process into distinct stages (pre-cooling, flash freezing, and holding phases) with dedicated control for each stage. This segmentation allows complex cryogenic freezing to be managed through simplified stage-specific control parameters, reducing overall system complexity while maintaining high product quality
Solution Approach 2:
The patent implements feedback control mechanisms that monitor temperature and adjust liquid nitrogen flow rates in real-time. This feedback system automatically maintains optimal freezing conditions without requiring complex manual control, simplifying operation while ensuring consistent high-quality results
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 method effectively suppresses protein denaturation, minimizes weight loss, and maintains the quality of frozen seafood, eliminating the need for preservatives and enhancing the preservation level and added value of the product while reducing liquid nitrogen consumption.
Implementation Method 1
an extremely high freezing strength instantly released by liquid nitrogen is used
Implementation Method 2
Using an ultra-low temperature, i.e., cryogenic, flash freezing technology using liquid nitrogen
Implementation Method 3
a temperature sensor A is configured to measure an internal ambient temperature of a flash freezing device, and a temperature sensor B is configured to measure a core temperature of a flash-frozen aquatic product
Data Source
AI summary
A high-precision control system and method for shipborne cryogenic flash freezing of an aquatic product using liquid nitrogen is described. The system may include a main control system, a display unit, a liquid nitrogen supply system, a valve control unit, an acquisition unit, and a power unit. A flash freezing process is divided into four stages: a precooling stage, a flash freezing stage, a deep freezing stage, and a thermal insulation stage. Different cooling rates and flash freezing times are used for different stages, where a cooling rate is used in the flash freezing stage is the highest, a cooling rate used in the deep freezing stage is next, a cooling rate used in the precooling stage is the lowest, and an ambient temperature in a device is kept stable in the thermal insulation stage.