Suction Device Screening Element Aperture Ratio for Plastic Strand Drying
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Solution Overview
Problem
Existing suction devices for drying plastic strands have inefficiencies due to mechanical sensitivity, short dwell time, and uneven air flow, leading to suboptimal drying performance.
Innovation Solution
A suction device with a longer screening element and strategically arranged apertures, combined with a cover element creating a flow channel, enhances air flow velocity and dwell time, improving drying efficiency while maintaining energy efficiency and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the screening element is made with a large number of bars of 2.2 mm width and 1.2 mm gaps, then the drying area is maximized, but the screening element becomes very sensitive to mechanical impact and can be damaged easily during cleaning
Solution Approach 1:
The patent changes the geometric parameters of the screening element by increasing the bar width to 5 mm and the gap width to 3 mm, while reducing the number of bars. This parameter modification maintains the drying area while significantly improving mechanical robustness and resistance to damage during cleaning operations.
2Speed
If the air velocity is increased to up to 50 m/s, then water is effectively removed from the strand surface, but the dwell time of plastic strands on the screening element becomes short, resulting in suboptimal drying performance
Solution Approach 1:
The patent extends the screening element length from the conventional 100 mm to at least 150 mm, adding length in the process direction. This dimensional extension increases the dwell time of plastic strands on the screening element, allowing more effective drying while maintaining high air velocity through the optimized aperture arrangement.
Solution Approach 2:
The patent optimizes the aperture cross-sectional area ratio to between 30% and 45% of the base area, which balances air velocity maintenance with extended dwell time. This parameter optimization ensures thorough drying performance.
3Device complexity
If the screening element length is limited to 100 mm, then the device complexity is reduced, but the drying performance is suboptimal due to short dwell time
Solution Approach 1:
The patent increases the screening element length parameter from the conventional 100 mm maximum to at least 150 mm, which improves drying performance by extending dwell time while maintaining acceptable device complexity through straightforward structural extension.
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 solution achieves improved drying performance with higher air flow velocities and longer dwell times, ensuring thorough water removal from plastic strands with reduced energy consumption and increased robustness for easier cleaning.
Implementation Method 1
a suction device is known which dries the plastic strands by means of a suction process
Implementation Method 2
This creates a flow channel between the cover element and the screening element, and through the screening element
Implementation Method 3
the velocity of the suction air flow acting on the plastic strand will be significantly lower, resulting in a poorer drying performance
Data Source
AI summary
A suction device for drying at least one plastic strand, incorporates a suction housing having a top side, a bottom side and several lateral surfaces, the top side having an inlet opening and one of the other surfaces having an outlet opening for the flow of a drying medium therethrough, and a screening element which has through apertures a base area with a maximum length and a maximum width. Each through aperture has an aperture cross-sectional area, and the sum of the aperture cross-sectional areas of all through apertures together forms a total aperture cross-sectional area. The screening element is on the top side and has its drying area above the inlet opening of the suction housing. The at least one plastic strand is moved in a process direction on the screening element, wherein the process direction is in a longitudinal direction of the screening element. The length of the drying area is at least 150 mm, and a ratio of the total aperture cross-sectional area of the through apertures to the base area of the drying area is between 30% and 45%, in particular 35% and 40%.