Stacked Air Impingement Tunnel Oven Venting With Variable Exhaust Speed
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Solution Overview
Problem
Commercial air impingement tunnel ovens with vertically stacked baking cases face operational challenges due to complex controls and excessive air flow, leading to improper ventilation and degraded cooking performance.
Innovation Solution
A vertically stacked air impingement tunnel oven with integrated switching and control systems for blower fan, conveyor motor, and exhaust fan, featuring variable and preset exhaust fan speed control to optimize air flow and reduce Bernoulli effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exhaust fan operates at high speed to properly vent lowermost oven, then ventilation of lowermost oven is improved, but excess air flow creates excessive Bernoulli effects at upper food passage ports, degrading cooking performance of uppermost oven
Solution Approach 1:
The exhaust fan speed is made variable rather than fixed, allowing it to be dynamically adjusted based on which oven(s) are in use. The system transitions from a static high-speed operation to a dynamic speed control system that adapts to different operational scenarios, eliminating excessive air flow when only upper ovens are used while maintaining proper ventilation when lower ovens are active.
Solution Approach 2:
The exhaust fan speed parameter is changed from a single fixed value to multiple variable speeds. By modifying the speed parameter based on which ovens are operational, the system optimizes air flow to prevent harmful Bernoulli effects at food passage ports while maintaining effective ventilation when needed.
2Adaptability or versatility
If multiple switches and controls are provided for burner ignitors, valves, conveyors, and impingement air fans, then control capability is improved, but improper settings and operation occur due to complexity
Solution Approach 1:
Multiple separate controls for burner ignitors, valves, conveyors, and impingement air fans are merged into a single integrated control system. The control panel consolidates these functions so that activating a single switch simultaneously controls all related components, eliminating the complexity of multiple independent controls while maintaining full operational capability.
Solution Approach 2:
The control system is designed with universal switches that perform multiple functions. Each control switch is multi-functional, capable of simultaneously controlling burner ignitors, valves, conveyors, and impingement air fans, thereby reducing the total number of controls needed while maintaining comprehensive control capability.
3Reliability
If exhaust fan speed is fixed for lowermost oven ventilation, then proper ventilation is achieved when all ovens are used, but excessive air flow degrades cooking performance when only upper ovens are utilized
Solution Approach 1:
The exhaust fan operates dynamically with variable speeds rather than a fixed speed. The system adapts the fan speed based on which ovens are currently in use, ensuring optimal ventilation when lower ovens are active while reducing speed to prevent harmful air flow effects when only upper ovens are utilized, thereby protecting cooking performance.
Solution Approach 2:
The control system incorporates feedback regarding which ovens are in use to automatically adjust exhaust fan speed. This feedback mechanism ensures the exhaust fan operates at appropriate speeds based on actual operational conditions, preventing excessive air flow that would degrade cooking performance while maintaining necessary ventilation.
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
Simplifies operation by allowing simultaneous actuation of heating and ventilation components, minimizing excess air flow and improving cooking performance by optimizing exhaust fan speed based on selected oven usage.
Implementation Method 1
Such excess air flow creates undesirable and excessive Bernoulli effects at such upper food passage ports, resulting in increases in aspiration of heated cooking gases
Data Source
AI summary
A vertically stacked air impingement tunnel oven including a plurality of baking cases having vertically aligned food ports; an electronically controlled heater system connected to the baking cases, the heater system being adapted for heating selected groups of baking cases, the heater system including a plurality of on/off switches which are correspondingly electrically connected for actuating the heating of the selected baking cases; an exhaust hood and exhaust fan having an inlet over the food ports; and a first electronic motor drive system connected operatively to the exhaust fan, and being adapted for rotating the exhaust fan a rotation speed among a plurality of preset rotation speeds, the drive system including the plurality of on/off switches which are further electrically connected for simultaneously actuating the exhaust fan at rotation speeds corresponding with the selected baking case group.