Coandă-Effect Nozzle Rotary Dryer for Vegetable Clump Prevention
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Solution Overview
Problem
Conventional rotary dryers face issues with clumping of vegetable material, which prevents uniform drying as the interior of clumps remains undried due to the 'skin' formed by air flow on the exterior, leading to inefficiencies and potential hazards from flammable dust.
Innovation Solution
A rotary dryer utilizing a Coandă-Effect nozzle body with a tear-shaped housing and opposed Coandă surfaces to create a laminar air flow that adheres to the surface, breaking up clumps and ensuring thorough drying, while a closed-loop air system with a squirrel-cage blower controls dust and maintains optimal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional rotary dryers use direct air contact with vegetable material, then drying efficiency is improved, but clumping occurs preventing uniform drying
Solution Approach 1:
The patent replaces the conventional mechanical cascading action with a Coandă-effect air flow system. A nozzle directs high-velocity air along the drum surface, creating a boundary layer that lifts and disperses material particles, preventing clump formation while maintaining high drying efficiency through sustained air-material contact.
Solution Approach 2:
The invention uses pneumatic principles by directing a controlled jet of heated air through a nozzle to create the Coandă effect. The air flow adheres to the curved drum surface, generating suction that lifts material particles and prevents them from settling into clumps, thereby achieving uniform drying throughout the material mass.
2Speed
If material is continuously tumbled in rotary dryer, then drying speed is improved, but interior moisture remains trapped in clumps
Solution Approach 1:
The patent replaces mechanical tumbling with pneumatic particle suspension. The Coandă-effect air flow continuously suspends and redistributes material particles along the drum surface, ensuring that interior portions of clumps are exposed to drying air without requiring aggressive mechanical breaking apart.
Solution Approach 2:
The Coandă-effect air flow acts as an intermediary between the heated air source and the material particles. It creates a controlled boundary layer that penetrates into clump structures, delivering heat and moisture removal capability to interior regions while the material remains in continuous gentle motion.
3Use of energy by moving object
If combustion chamber is integrated into dryer, then heating efficiency is improved, but dust explosion hazard increases
Solution Approach 1:
The patent extracts the combustion chamber from the dryer system, separating the heating function from the drying chamber. An external heat source heats air that is then supplied to the dryer through controlled openings, eliminating the dust explosion hazard while maintaining heating efficiency through controlled air-to-material contact.
Solution Approach 2:
The invention applies preliminary anti-action by controlling the timing and location where heated air contacts material particles. Air is heated separately and only contacts material at controlled points in the drying chamber, preventing the formation of explosive dust-air mixtures while still achieving efficient moisture removal.
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 35% reduction in moisture content and effectively prevents clumping, ensuring uniform drying and minimizing dust-related hazards through efficient air flow management.
Implementation Method 1
A plenum feeds air through a nozzle opening in a rectangular slot extending in its longest dimension substantially the length of the drum. The plenum and nozzle being housed to form a Coandă-effect nozzle body having a tear-shaped housing. Two Coandă surfaces are situated in opposed relation and terminating at the nozzle.
Implementation Method 2
a closed-loop air system with a squirrel-cage blower controls dust and maintains optimal pressure
Implementation Method 3
The exhaust blower is connected to blow the exhaust volume of heated air and dust into a cyclone separator. The cyclone separator allows the heated air to escape to the ambient and to drop dust into the infeed hopper
Implementation Method 4
The removal of water from a mass of vegetable material by evaporation is often necessary to stabilize the material
Data Source
AI summary
A cylindrical drum having a plurality of vanes which extend radially into the drum and extend axially substantially the length of the drum rotates about its axis such that the plurality of vanes convey vegetable material from a lowest point in the interior of the drum to a highest point in the interior of the drum, there, to drop the vegetable matter downward within the interior of the drum. A plenum feeds air through a nozzle opening in a rectangular slot extending in its longest dimension substantially the length of the drum. The plenum and nozzle being housed to form a Coand{hacek over (a)}-effect nozzle body having a tear-shaped housing. Two Coand{hacek over (a)} surfaces are situated in opposed relation terminating at the nozzle. The Coand{hacek over (a)} surfaces to guide air into a combined flow. A hopper plate cooperates with the housing to form a hopper directing vegetable matter to collide with the combined flow.