Liquid Cryogen Delivery Control Using Exhaust Gas Temperature Feedback
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Solution Overview
Problem
Existing methods for controlling liquid cryogen delivery in refrigeration and freezing applications are inefficient due to reliance on temperature probes prone to debris buildup, viscosity sensing requiring phase change, and high-pressure bulk storage tanks, leading to inaccurate delivery and increased costs.
Innovation Solution
A delivery apparatus and method that utilize a weight measurement device and flow controller to regulate liquid cryogen delivery based on exhaust gas temperature, reducing cryogen pressure as the product cools, and incorporating a high-pressure gaseous cryogen tank to maintain efficient cryogen flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature probes are used to control liquid delivery based on product temperature, then delivery control is achieved, but the probes are difficult to keep clear of product build-up and debris, and accurate temperature readings are difficult to obtain
Solution Approach 1:
The patent uses exhaust gas temperature as an intermediary indicator to infer product temperature. Instead of directly measuring product temperature with probes that contaminate, the system measures the temperature of exhaust gas which reflects the thermal state of the chilling process, thereby eliminating the need for direct product contact measurement
2Measurement precision
If viscosity sensing is used to control liquid delivery, then delivery control is achieved, but the products must undergo partial phase change and additional devices are required
Solution Approach 1:
The system uses exhaust gas temperature as an intermediary parameter to control liquid cryogen delivery, replacing complex viscosity sensing systems. This approach eliminates the need for motor power sensors, phase change detection devices, and additional control equipment while maintaining accurate delivery control
Solution Approach 2:
The patent changes the control parameter from product viscosity or temperature to exhaust gas temperature. This parameter change simplifies the measurement system and eliminates the requirement for products to undergo phase change, as exhaust gas temperature can be measured throughout the chilling process
3Speed
If high-pressure bulk storage tanks are used to deliver liquid cryogen quickly, then delivery speed is improved, but the tanks are costly and inefficient to operate
Solution Approach 1:
The patent implements dynamic pressure control where the system maintains high pressure only when rapid delivery is needed and reduces pressure when delivery speed can be reduced. This dynamic adjustment optimizes both delivery speed and energy efficiency, eliminating the need for continuously operating high-pressure bulk storage tanks
Solution Approach 2:
The system dynamically changes the pressure parameter of liquid cryogen delivery based on process needs. By adjusting pressure from high to low levels, the system achieves fast delivery when required while maintaining operational efficiency during normal operation, replacing the need for expensive high-pressure bulk storage infrastructure
4Speed
If high-pressure bulk storage tanks are used to ensure quick delivery, then delivery speed is improved, but the tanks are costly to operate
Solution Approach 1:
The patent implements dynamic pressure control where high pressure is applied only when rapid delivery is needed and reduced when delivery speed can be lowered. This dynamic adjustment optimizes both delivery speed and operating cost, eliminating the need for continuously operating expensive high-pressure bulk storage tanks
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
Improves efficiency and consistency of cryogen delivery, reducing energy consumption and maintaining optimal chilling performance by adjusting cryogen flow according to exhaust gas temperature, avoiding excess cryogen use and ensuring precise heat transfer.
Implementation Method 1
the chilling application uses the liquid cryogen to produce an exhaust gas
Implementation Method 2
a weight measurement device for controlling a weight of the liquid cryogen to be delivered
Data Source
AI summary
A delivery apparatus and method for delivering liquid cryogen to a chilling application includes a liquid cryogen feed tank; a liquid cryogen conduit in fluid communication between the liquid cryogen feed tank and the chilling application, wherein the chilling application uses the liquid cryogen to produce an exhaust gas; a device for measuring a temperature of the exhaust gas, the device in operative communication with a controller; and wherein the controller is in communication with the temperature measuring device and a flow control valve, and is configured to receive a signal corresponding to the temperature of the exhaust gas from the temperature measuring device to vary the speed of delivery of the liquid cryogen through the liquid cryogen conduit to the chilling application in response to the temperature of the exhaust gas.