Plastic Material Drying With Bin-Specific Airflow Control
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Solution Overview
Problem
Existing plastic material drying systems waste energy by supplying excessive drying air to all drying bins, regardless of their size or material requirements, leading to the risk of overdrying.
Innovation Solution
A method and system that regulate the actual air quantity in each drying bin and the total air quantity generated by a drying air generator based on flow measurement, using orifice plate flow meters and differential pressure, with control valves and controllers to optimize air distribution according to bin size and material needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drying air generator supplies maximum air quantity to all drying bins based on 100% air quantity design, then all drying bins receive sufficient air for drying, but smaller drying bins receive more air than needed leading to energy waste and risk of overdrying
Solution Approach 1:
The patent divides the total air quantity from the drying air generator into individual portions for each drying bin using separate control valves (7a, 7b, 7c). Each drying bin receives a segmented air supply that can be independently regulated according to its specific needs, rather than receiving a uniform maximum air supply. This segmentation allows smaller bins to receive appropriate air quantities without waste while larger bins continue to receive sufficient air for effective drying.
Solution Approach 2:
The patent implements dynamic air quantity regulation for each drying bin through control valves that can adjust the air supply in real-time. The air quantity to each bin is no longer fixed at maximum capacity but can be dynamically adapted based on the bin size, material type, and drying requirements. This dynamic adjustment eliminates the static 100% air quantity design that caused energy waste.
2Productivity
If the drying air generator supplies maximum air quantity to all drying bins, then drying process can be performed simultaneously in multiple bins, but the quantity of drying air allocated to each individual drying bin is not optimal
Solution Approach 1:
The patent implements feedback control for each drying bin by measuring the actual air quantity with flow meters (8a, 8b, 8c) and comparing it to the desired air quantity. The control unit (12) receives feedback signals from the flow meters and adjusts the control valves accordingly to maintain the optimal air quantity for each bin. This closed-loop feedback system ensures precise air quantity control while maintaining high productivity across multiple drying bins.
Solution Approach 2:
The patent uses a single drying air generator (17) that serves multiple drying bins (1a, 1b, 1c) simultaneously, demonstrating multi-functionality. The generator produces a total air quantity that is then universally distributed to various bins with different requirements through individual control valves. This universal air supply system maintains productivity while the individual control mechanisms ensure each bin receives the precise air quantity it needs.
3Loss of energy
If flow measurement and regulation systems are installed in each drying bin, then precise air quantity control is achieved, but device complexity increases
Solution Approach 1:
The patent merges the control functions for multiple drying bins into a single centralized control unit (12) that manages all control valves (7a, 7b, 7c) and receives feedback from all flow meters (8a, 8b, 8c). This consolidation reduces the complexity that would arise from having completely independent control systems for each bin. The merged control approach maintains precise energy-efficient air quantity regulation while simplifying the overall system architecture through centralization.
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 approach ensures efficient energy use by supplying only the necessary air quantity, preventing overdrying and reducing energy waste, while allowing precise control of the drying process.
Implementation Method 1
The air quantity to be supplied to the drying bin can be adapted optimally to the size of the drying bins and/or the plastic material to be dried and/or the throughput of the drying bin. A differential pressure is advantageously measured at the orifice plate flow meter. For this, the pressure is detected upstream and downstream of the orifice plate flow meter and the differential pressure is determined in this way.
Implementation Method 2
The orifice plate flow meter causes a back-pressure to be generated, which can be advantageously adjusted with regard to optimising the drying process. For this purpose, a control valve is advantageously provided, which can be adjusted according to requirements, preferably using an appropriate motor.
Data Source
AI summary
In a method for drying plastic material in the form of granules, powder and the like, at least one drying air generator generates drying air which is conducted through plastic material situated in a drying bin. The drying air absorbs the moisture in the plastic material and exits from the drying bin as return air. An actual air quantity of the drying air supplied to the drying bin is detected by a flow measurement and regulated to a setpoint air quantity. An actual total air quantity of the drying air exiting from the drying air generator is regulated to a setpoint total air quantity. At least two drying bins are connected to the drying air generator by means of a drying air duct and a return air duct. In the drying air duct, there is an orifice plate flow meter, which is connected upstream of a motor-adjustable control valve.