Cryogen Control for Food Product Viscosity via Enthalpy Calculation
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Solution Overview
Problem
Current methods for metering and controlling the delivery of liquid cryogens in refrigeration and freezing systems are inaccurate due to two-phase flow issues, leading to excessive cryogen use and inefficiencies in achieving desired temperatures and viscosities for food processing, resulting in high operational costs and processing difficulties.
Innovation Solution
A method that uses product enthalpy and weight-based injection to calculate the precise amount of liquid cryogen needed to achieve the desired viscosity and temperature of food products, eliminating operator discretion and providing a recordable delivery history for optimized cryogen usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid cryogen is delivered through a conduit to cool food products, then the food product temperature is reduced to desired levels, but the cryogen undergoes phase change to gas making accurate metering difficult
Solution Approach 1:
The patent replaces mechanical flow measurement devices (volumetric flow meters, Coriolis mass flow meters, turbine flow meters) with an enthalpy-based calculation system. The system calculates the required cryogen amount based on thermodynamic principles (enthalpy change of the food product) rather than measuring the actual cryogen flow, thereby avoiding the two-phase flow measurement problem entirely.
Solution Approach 2:
The patent changes the control parameter from cryogen flow rate (which is difficult to measure accurately in two-phase flow) to food product enthalpy change (which can be calculated from temperature and mass measurements). This parameter transformation allows accurate determination of cryogen requirements without directly measuring the problematic two-phase flow.
2Quantity of substance
If conventional flow meters are used to measure cryogen delivery, then volume or mass flow can be monitored, but the gaseous portion occupies excessive space causing up to 50% metering error
Solution Approach 1:
The patent eliminates mechanical flow measurement systems that are susceptible to two-phase flow errors. Instead, it uses a computational approach based on enthalpy balance calculations, where the cryogen quantity is determined by the thermal energy required to cool the food product, not by direct flow measurement.
Solution Approach 2:
The patent introduces enthalpy calculation as an intermediary between the cryogen delivery system and the control system. Rather than directly measuring cryogen flow (which is inaccurate), the system calculates the required cryogen amount through thermodynamic relationships, using food product temperature and mass data as intermediaries.
3Temperature
If temperature probes are used to monitor food product cooling, then temperature readings can be obtained, but product build-up on mixer walls and voids in product prevent accurate readings
Solution Approach 1:
The patent replaces physical temperature probes that contact the food product with a non-contact enthalpy calculation system. The system calculates the average food product temperature based on energy balance principles, using measurements of food product mass, initial temperature, and added cryogen quantity, thereby avoiding probe contamination issues.
4Ease of operation
If operator discretion is used to determine cryogen amount, then flexibility in processing is maintained, but excessive cryogen usage occurs due to inability to precisely control delivery
Solution Approach 1:
The patent implements a feedback control system where the required cryogen amount is calculated based on the actual food product characteristics (mass, initial temperature) and the desired final temperature. The system automatically adjusts the cryogen delivery to match the precise requirement, eliminating both operator discretion errors and cryogen waste.
Solution Approach 2:
The system enables self-regulating cryogen delivery by automatically calculating and controlling the cryogen amount based on process parameters. The control system serves itself by using process data to determine the exact cryogen requirement, eliminating the need for operator judgment and preventing over-delivery.
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
Enables accurate and efficient delivery of cryogen, reducing waste and ensuring consistent product viscosity for seamless processing, with automatic predictive cryogen delivery and reduced operator errors, while maintaining a historical record of cryogen usage.
Implementation Method 1
introducing an amount of cryogen into the batch based upon enthalpy of the batch for arriving at the processing temperature
Implementation Method 2
it is extremely difficult if not impossible to sufficiently insulate a conduit conveying the liquid cryogen to keep some of the liquid cryogen from evolving or changing phase into gas
Implementation Method 3
a certain percentage of the volume flowing through the conduit consists of the gaseous form of the cryogen (resulting in two-phase flow)
Implementation Method 4
it is extremely difficult if not impossible to sufficiently insulate a conduit conveying the liquid cryogen
Data Source
AI summary
A method for adjusting a viscosity of a food product for processing in a mixer includes measuring a weight and introductory temperature of a batch of the food product; determining a viscosity of the batch of the food product necessary for subsequent processing; determining a processing temperature of the batch necessary to arrive at the viscosity; and introducing an amount of cryogen into the batch based upon enthalpy of the batch for arriving at the processing temperature.