Drying Tunnel Plenum for Uniform Fruit Airflow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fruit drying tunnel systems suffer from non-uniform air flow distribution, leading to inefficient drying performance, with hot air tending to accumulate in the upper portion and resulting in uneven drying across the fruit, increased energy consumption, and reduced productivity.
Innovation Solution
A drying tunnel design featuring a plenum with circular or oval holes arranged in a staggered pattern on the lower surface, releasing hot air perpendicularly to the conveyor system, maintaining constant pressure and temperature, and utilizing an aspirator to recirculate and mix air for improved air flow and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hot air is applied from the upper portion of the tunnel, then the air flow favors the outlet of water by gravity, but the hot air accumulates in the upper portion resulting in non-uniform drying
Solution Approach 1:
The patent transitions from upper portion air application to lower portion air ejection, changing the spatial dimension of hot air delivery. The plenum chamber with holes in the lower surface directs air upward from below, fundamentally altering the flow direction and achieving uniform distribution across all fruit surfaces without accumulation in one area.
Solution Approach 2:
The patent extracts the hot air generation and delivery function from the upper portion of the tunnel and relocates it to the lower portion through the plenum chamber. This separation allows independent optimization of air delivery mechanics, enabling uniform distribution while maintaining effective water removal through the conveyor system.
2Productivity
If fans are installed in the upper portion to accelerate air flow, then drying performance increases, but non-uniform flow is generated and energy consumption increases
Solution Approach 1:
The plenum chamber with multiple holes creates a self-distributing air flow system where hot air automatically reaches all areas through the hole array, eliminating the need for additional fans to force uniform distribution. The system serves itself by design geometry rather than active mechanical intervention, reducing energy consumption while maintaining productivity.
Solution Approach 2:
The patent applies hot air locally through numerous small holes distributed across the plenum chamber surface, ensuring each region receives appropriate air flow directly at the point of need. This localized delivery through the hole array achieves uniform drying across different tunnel sections without requiring high-energy fan systems to force air to distant areas.
3Speed
If lateral fans are used to suction air from the lower portion, then turbulent flow is created, but the fans do not reach full tunnel width resulting in center-side drying differences
Solution Approach 1:
The patent segments the air delivery system into multiple small holes distributed across the entire plenum chamber width, replacing the single lateral fan approach. This segmentation allows air to be delivered at multiple points simultaneously across the full tunnel width, ensuring uniform flow speed and drying performance from center to sides without the limitations of centralized fan coverage.
4Speed
If vertical or inclined fans are installed from the middle of the duct, then air speed increases, but the speed and temperature have already decreased causing reduced efficiency
Solution Approach 1:
The patent implements preliminary action by delivering hot air at high temperature and pressure from the plenum chamber at the beginning of the fruit path, before the air has a chance to cool. The holes in the plenum chamber release air immediately onto the fruit surfaces, maximizing the utilization of thermal energy before heat loss occurs, thereby improving overall energy efficiency while maintaining high air speed for effective drying.
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 design achieves a more uniform and efficient air flow distribution, doubling the productivity of the tunnel by ensuring all fruit surfaces receive direct and consistent hot air, reducing energy consumption, and enhancing the mechanical removal of water, thereby improving the drying process.
Implementation Method 1
a plenum (3), with circular or oval holes (10) in a staggered arrangement on its lower surface, for releasing an outgoing hot air current (6) in a distributed way towards a conveyor system
Implementation Method 2
utilizing an aspirator to recirculate and mix air for improved air flow and energy efficiency
Implementation Method 3
The plenum (3), with circular or oval holes (10) in a staggered arrangement on its lower surface, for releasing an outgoing hot air current (6) generated in a turbine
Implementation Method 4
the outgoing hot air current (6) generated in a turbine and in a heat generator
Data Source
AI summary
The present disclosure consists of a drying tunnel for fruits or vegetables which comprises an impulsion and heating chamber and a plenum, configured for receiving an outgoing hot air generated in the impulsion and heating chamber by the generator, so that the plenum comprises openings arranged in a staggered pattern, located on the lower surface thereof, with an opening density between 150 to 300 openings per square meter, wherein said openings are configured for expelling a distributed hot air from inside the plenum in a perpendicular way towards a conveyor system, configured for moving fruits and vegetables to be dried.