Two-Stage Air Heating System for Uniform Drying
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Solution Overview
Problem
Current drying systems in the textile and paper industries face challenges in maintaining a uniform temperature profile across the web, leading to inefficient energy use and potential damage to lightweight materials due to non-homogenous heating profiles, which requires larger systems and increased energy expenditure.
Innovation Solution
A two-stage air heating system that divides system air into separate conduits for sequential mixing with combustion products and external heated air, using injection chambers and mixing chambers to ensure uniform temperature distribution, allowing for compact and energy-efficient dryer designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If system air is combined with combustion products in a single stream, then heating efficiency is improved, but temperature profile uniformity deteriorates
Solution Approach 1:
The air stream is divided into multiple separate streams that are heated independently through different conduits. System air is split into first and second portions, each traveling through separate heating paths before being recombined, allowing independent temperature control to maintain uniformity while achieving efficient heating.
Solution Approach 2:
Multiple intermediate heating zones are introduced between the combustion source and the final mixed air stream. Each zone processes a separate air portion through its own conduit system with dedicated heating elements, acting as intermediaries that prevent direct thermal contamination from combustion products while maintaining overall heating efficiency.
2Stability of the object's composition
If a static mixer is used to mix air streams, then mixing effectiveness is improved, but system complexity increases
Solution Approach 1:
The system replaces static mixing structures with dynamic flow management. Air streams are actively directed through multiple conduits and recombined through controlled flow paths rather than passive static mixers, allowing the mixing process to be integrated into the existing dynamic air circulation system of the dryer.
Solution Approach 2:
The mixing function is merged with the existing air circulation system. The separate air streams are recombined through the natural flow paths and pressure differentials already present in the dryer's air handling system, eliminating the need for separate mixing devices and reducing overall system complexity.
3Manufacturing precision
If recirculation distance is increased to ensure uniform temperature, then temperature uniformity is improved, but system size increases
Solution Approach 1:
The system transitions from relying on longitudinal distance for mixing to using a multi-dimensional conduit network. Air streams are separated and recombined through vertical and lateral conduit arrangements rather than simply extending the recirculation path horizontally, achieving uniformity without increasing the overall system footprint.
Solution Approach 2:
Multiple conduit systems are nested within the existing dryer structure. The separate heating conduits are integrated into the available space within the dryer housing, allowing complex multi-stream processing to occur within the same physical envelope rather than requiring additional external space.
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 two-stage heating process enhances drying efficiency, reduces system size, and minimizes energy consumption while maintaining uniform temperature profiles, addressing the need for compact, energy-efficient, and cost-effective drying solutions.
Implementation Method 1
combustion products from a burner (38)
Implementation Method 2
mixed air stream (44) that is uniformly heated
Implementation Method 3
inducing turbulence and mixing into the mixed air 134 stream
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Novel dryer systems incorporate two-stage processes for heating air for drying a traveling web. The dryer operates within a drying system having a drying hood containing a dryer. The drying hood receives heated air through an intake and expels system air through an exhaust, a portion of which is directed into the atmosphere. The portion of system air that is maintained in the system is divided into two portions and directed into separate parallel conduits for two-stage heating that results in greater temperature uniformity and efficiency within the system. One loop initially mixes system air with the combustion products of a burner. A second loop receives the initially mixed air and injects it into the other portion of the system air, resulting in greater temperature uniformity within the drying hood and increased operating efficiency for the entire system. The dryer efficiently uses supplemental heat.