Vertical Food Cabinet Shelves Using Pressurized Heat-Transfer Fluid
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Solution Overview
Problem
Existing vertical food cabinets struggle to maintain food at temperatures above 93.3°C (200°F) without causing overcooking, as they often rely on heating methods that either fail to maintain precise temperature control or lead to additional cooking of the food.
Innovation Solution
A vertical food cabinet design featuring a heat transfer arrangement with a pump, supply and return manifolds, fluid conduits, a primary tank with a pressure release valve, and an auxiliary tank, which operates at increased pressure and temperature, allowing for efficient heat transfer and flexibility in cooking and holding temperatures, while preventing overcooking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electrically heated air or steam is used to maintain food at temperatures above 60°C, then the food temperature can be maintained, but considerable undesired additional cooking or overcooking of the food occurs
Solution Approach 1:
The patent introduces a heat transfer medium (water or aqueous solution) as an intermediary between the heating source and the food. This medium circulates through conduits in the shelf support structure, providing indirect heat transfer that is more controllable and less likely to cause overcooking compared to direct heating methods like electrically heated air or steam.
Solution Approach 2:
The system employs a hydraulic circulation system where a pump moves the heat transfer medium through a closed loop of conduits integrated into the shelf supports. This hydraulic approach allows precise control of heat delivery to different zones, enabling maintenance of food at temperatures above 60°C without the uncontrolled heating that causes overcooking.
2Measurement precision
If a heat transfer medium is circulated through conduits in shelf supports, then precise temperature control is achieved, but the device complexity increases due to pump, manifolds, and fluid level monitoring systems
Solution Approach 1:
The patent combines multiple functions into the shelf support structure itself. The shelf supports serve both as structural elements and as heat distribution components by incorporating internal conduits. This integration reduces the need for separate heating elements and simplifies the overall system architecture despite the added temperature control capabilities.
Solution Approach 2:
The system includes automatic fluid level monitoring and control mechanisms that operate without constant manual intervention. The fluid level sensors and pump control systems automatically maintain proper heat transfer medium levels, reducing operational complexity and enabling precise temperature control through self-regulating mechanisms.
3Productivity
If the heat transfer medium temperature is increased above 93.3°C to improve cooking efficiency, then cooking speed increases, but the risk of overcooking increases
Solution Approach 1:
The system dynamically adjusts the temperature of the heat transfer medium and the circulation flow rate based on the specific cooking requirements and food load conditions. The pump speed and heating element output can be varied to optimize cooking efficiency while preventing overcooking, allowing operation at temperatures above 93.3°C when appropriate while maintaining safety margins.
Solution Approach 2:
Different zones within the cabinet can have different heat transfer medium temperatures and flow rates, allowing high-temperature rapid cooking in specific areas when needed while maintaining lower temperatures in other zones to prevent overcooking. This localized control enables improved cooking efficiency in priority areas without compromising food safety elsewhere.
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 effectively maintains food at elevated temperatures above 93.3°C (200°F) without overcooking, providing increased efficiency and flexibility, and includes sensors for fluid level monitoring to prevent heater burnout and ensure continuous operation.
Implementation Method 1
forcing a heated liquid heat-transferring medium through a manifold located adjacent to each shelf
Implementation Method 2
circulated therethrough
Implementation Method 3
When the heat transfer medium heats up, it expands, causing the pressure to build up
Implementation Method 4
the pressure pushes the valve open, allowing the heat transfer medium to flow from primary tank 24 to auxiliary tank 26
Implementation Method 5
Fluid conduits 22 are coupled in parallel with pump 20, thereby maintaining a substantially constant temperature from one shelf to another
Data Source
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AI summary
A food cabinet is provided that includes an enclosure with an access door, shelves carried by and vertically arranged within the enclosure, and a heat transfer arrangement. The heat transfer arrangement includes a pump, fluid conduits coupled with the pump and associated with the shelves of the enclosure, a primary tank, and an auxiliary tank. The primary tank is fluidly connected to the pump and contains a heat transfer medium. The auxiliary tank is coupled with the primary tank and provides make-up heat transfer medium to the primary tank. Also provided is a method of warming food using such a food cabinet that includes the steps of placing a food item on one of the shelves, heating the heat transfer medium to a temperature between 200°F and 250°F, and pumping the heat transfer medium through the shelf.