Tunnel Rotary Drum Airflow Layout for Efficient Clothes Drying
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Solution Overview
Problem
Existing tunnel-type rotary drum tumble dryers face inefficiencies in hot air circulation due to small perforation passages, leading to reduced drying efficiency and clothing movement towards lower-level perforations blocking air flow.
Innovation Solution
The design features an air circulation system with an air inlet above and an air outlet below the drum's geometric axis, creating a direct axial flow of drying air through the drum, and incorporates an inclined drum or frustoconical wall to prevent clothing from moving towards the unloading door during drying, with optional oblique blades for automatic unloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot air circulation is introduced through perforations in the cylindrical wall, then drying of clothing is achieved, but the passage area of the perforations is relatively small compared with the area of the cylindrical wall resulting in inefficient hot air circulation and a large part of the flow circulating around the drum without penetrating therein
Solution Approach 1:
The cylindrical wall is divided into multiple zones with different perforation characteristics. The lower portion has perforations with larger passage area to improve air penetration efficiency, while the upper portion has perforations with smaller passage area to control air flow and prevent short-circuiting. This segmentation allows each zone to optimize its function for overall drying efficiency.
Solution Approach 2:
Different regions of the cylindrical wall are given different local qualities in terms of perforation density and passage area. The lower portion features larger passage area perforations to maximize air intake and penetration into the clothing, while the upper portion has smaller passage area perforations to regulate air flow and ensure thorough drying. This local differentiation resolves the contradiction between air flow volume and drying effectiveness.
2Productivity
If the drum rotates with clothing tumbling therein, then drying is facilitated, but the items to be dried have the tendency to block the perforations of the wall of the drum in areas located at a lower level forcing the hot air to enter and exit the drum through the perforations of the areas at a higher level
Solution Approach 1:
The cylindrical wall is segmented vertically into a lower portion and an upper portion with distinct perforation characteristics. The lower portion has perforations specifically designed with larger passage area to prevent blocking by tumbling clothing, while the upper portion has perforations with smaller passage area for controlled air discharge. This vertical segmentation ensures continuous air flow regardless of clothing position during drum rotation.
Solution Approach 2:
The problem of perforation blocking is solved by transitioning from a uniform perforation distribution to a vertically stratified distribution. By differentiating the perforation characteristics along the vertical dimension of the cylindrical wall, the system ensures that air can always enter through the lower portion (less prone to blocking) and exit through the upper portion, maintaining air flow efficiency throughout the drying cycle.
3Device complexity
If the drum has a horizontal or inclined geometric axis, then the structure is simplified, but the clothing has a tendency to move towards the unloading door due to gravity
Solution Approach 1:
The cylindrical wall is designed with asymmetric perforation distribution relative to the drum's geometric axis. The perforations are concentrated in the lower portion of the drum, creating an asymmetric air flow pattern that generates a counterbalancing force against gravity. This asymmetric configuration prevents clothing from sliding towards the unloading door while maintaining the simplicity of the horizontal or inclined drum axis structure.
Solution Approach 2:
The system uses pneumatic forces generated by the air circulation through the asymmetrically positioned perforations to counteract gravitational forces on the clothing. The air flow entering through the lower perforations creates pressure and flow patterns that push the clothing away from the unloading door, compensating for the gravitational tendency without requiring additional mechanical components or changing the drum's geometric axis orientation.
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 configuration enhances drying efficiency with reduced energy expenditure and facilitates automatic unloading by counteracting clothing movement, ensuring effective air penetration and efficient drying.
Implementation Method 1
air circulation means for introducing and extracting drying air into/from the drum while the latter rotates with clothing tumbling therein
Implementation Method 2
creating a flow of drying air inside the drum and in the axial direction thereof substantially from one end to another through the clothing tumbling inside the drum
Implementation Method 3
the items to be dried, which, as a result of the rotation of the drum tumble on the areas of the drum which are at a lower level, have the tendency to block the perforations of the wall of the drum in these areas located at a lower level
Data Source
AI summary
A tunnel-type rotary drum tumble dryer includes a cabinet (1) with a loading door (2) and an unloading door (3) on opposite sides, and a drum (4) arranged inside the cabinet (1) for rotating with respect to a horizontal or inclined geometric axis (E). The drum (4) has a revolution wall (5) around the axis (E), and end openings (5a, 5b) at opposite ends facing said loading and unloading doors (2, 3). The tumble dryer also includes an air circulator that includes an air inlet (8) facing one of the end openings (5a, 5b) of the drum (4) and an air outlet (9) adjacent to the other end opening (5a, 5b) of the drum (4) for creating an axial flow of drying air inside and from one end to another of the drum (4) through the clothing tumbling inside the drum (4).