Non-Woven Web Drying System Humidity Control
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Solution Overview
Problem
The existing methods for drying non-woven materials produced using the water jet bonding technique face challenges with high relative humidity in the air currents, leading to rewetting of the web rather than effective drying, especially at lower temperatures, which disrupts the drying process and energy efficiency.
Innovation Solution
A method involving the controlled reheating of humidified air to maintain a relative humidity of less than 100% by adjusting the temperature and air flow, ensuring that the air does not reach saturation and prevent condensation on the web, while also ensuring all air is suctioned to prevent pollution and optimize energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air is reheated to dry the web, then drying efficiency is improved, but relative humidity increases causing rewetting of the web
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the temperature and flow rate of the air current passing through the web. The system modifies these parameters in real-time based on measured humidity levels to maintain optimal drying conditions without causing rewetting. This resolves the contradiction by enabling efficient drying while preventing the relative humidity from reaching saturation levels that would cause web rewetting.
Solution Approach 2:
The patent implements feedback control by measuring the humidity level of the air current after it passes through the web and using this information to adjust the heating and airflow parameters. This closed-loop system ensures that the air remains below saturation levels throughout the drying process, preventing rewetting while maximizing drying efficiency. The feedback mechanism allows continuous optimization of the drying process.
2Reliability
If air temperature is increased to prevent saturation, then rewetting is prevented, but energy consumption increases
Solution Approach 1:
The patent applies dynamics by making the air temperature and flow rate adjustable rather than fixed. The system dynamically adapts these parameters based on real-time humidity measurements, using only the necessary energy to maintain air below saturation levels. This dynamic approach prevents rewetting while minimizing energy consumption compared to maintaining constantly high temperatures.
Solution Approach 2:
The system changes temperature and flow rate parameters based on actual drying needs and measured humidity levels. By adjusting these parameters dynamically rather than maintaining constant high temperatures, the system achieves stable drying process while reducing overall energy consumption. The parameter adjustment is driven by feedback from humidity sensors.
3Productivity
If air flow rate is increased to remove humidity, then drying efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of air flow rate based on real-time humidity measurements. The system increases flow rate only when and where needed to maintain effective drying, then reduces it to minimize energy consumption. This dynamic flow control achieves high drying rates during critical phases while minimizing overall energy usage through intelligent parameter management.
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 effectively prevents rewetting of the non-woven web, minimizes energy consumption, and maintains the quality of the drying process by ensuring the air remains below saturation levels, thereby enhancing the drying efficiency and web quality.
Implementation Method 1
a heat source 4 which heats the air
Implementation Method 2
the water contained in the web is evaporated as the web advances on the drum 2
Implementation Method 3
Pressurised hot air is injected into the hood 3 by means of a fan V16
Implementation Method 4
a probe for the humidity level mounted in the extraction pipe for measuring the level of humidity in the air evacuated from the drying device
Implementation Method 5
the relative humidity of humidified air which leaves the drying device is controlled to a guide level of less than 100%
Data Source
AI summary
An installation for drying a web of non-woven material includes a fan (6), a heating oven (3), an outlet pipe (C2) which puts the outlet of the oven (3) in communication with the intake of the fan (6), a branch pipe (C3) branching from the inlet pipe (C1) upstream of the heat source (4) putting the pipe (C1) in communication with the inlet of a drying device (10, 11), a pipe (C4) for the extraction of air from the drying device (10, 11) and a humidity level probe (13) mounted in the extraction pipe (C4).