Dryer Air Mixing Control for Stable Process Temperature
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Solution Overview
Problem
Commercial tumble dryers face high energy consumption due to heat loss when exhaust air is discharged, and existing air recycling technologies have limitations in maintaining optimal process temperatures, leading to potential heating interruptions and reduced service life of heating components.
Innovation Solution
A control element that dynamically adjusts the ratio of circulating air to exhaust air within the tumble dryer's air duct system based on a setpoint temperature, using a mixed air element and a controller to regulate the proportion of recirculated air and supply air, ensuring optimal process air temperature and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a rigid air separation with constant proportions of exhaust air and circulating air is used, then the air paths are clearly separated and the structure is simple, but the process air temperature cannot be maintained optimally leading to heating interruptions
Solution Approach 1:
The patent applies dynamics by replacing the rigid, fixed-position air separation plates with a controllable air separation device that can dynamically adjust the separation ratio between exhaust air and circulating air. This allows the system to adapt the process air temperature in real-time, preventing heating interruptions while maintaining clear air path separation through active control mechanisms.
2Loss of energy
If a high proportion of circulating air is used to reduce energy consumption, then heating efficiency improves, but the process air temperature may become too high causing heating interruptions
Solution Approach 1:
The patent implements feedback control by continuously monitoring the process air temperature and using this information to dynamically adjust the air separation ratio. When the temperature approaches the heating element's maximum capacity, the system automatically increases the exhaust air proportion to prevent overheating and heating interruptions, thereby maintaining optimal energy efficiency while ensuring continuous reliable operation.
3Device complexity
If the air separation ratio is fixed, then the device structure is simple and cost-effective, but the service life of heating components is reduced due to temperature fluctuations
Solution Approach 1:
The patent extends heating component service life by implementing a dynamic air separation system that continuously adapts the circulating air to exhaust air ratio based on real-time temperature conditions. This prevents excessive temperature fluctuations and thermal stress on heating components, reducing wear and extending their operational lifespan while maintaining relatively simple device architecture through controlled adjustment mechanisms.
4Reliability
If dynamic adjustment of air flow ratios is implemented, then process air temperature can be maintained optimally, but the device complexity increases
Solution Approach 1:
The patent balances improved temperature control against increased complexity by implementing feedback control through controllable air separation devices that adjust the circulating air to exhaust air ratio based on monitored temperature conditions. This ensures optimal and reliable process air temperature maintenance while managing device complexity through targeted, condition-based adjustment mechanisms rather than overly complex control systems.
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 solution maintains a constant optimal process air temperature, reduces energy consumption, and extends the service life of heating components by dynamically adjusting the air flow ratios, thereby shortening drying time and improving overall energy efficiency.
Implementation Method 1
a fan (4) which is designed to generate a process air flow (A) within an air duct (1)
Implementation Method 2
a heating element (2) which is designed and arranged to heat the process air flow (A)
Implementation Method 3
the process air is then routed away from the laundry drum via an air return duct... a blower, i.e. a process air blower, through an air supply duct
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a clothes dryer (0) with a blower (4) configured to generate a process airflow (A) within an air duct (1), and with a mixing air element (5) configured to receive the process airflow (A) from the blower (4) and divide it into a recirculated airflow and an exhaust airflow (B), to discharge the exhaust airflow (B) to the environment via an exhaust air path (6), and to supply the recirculated airflow with a supply airflow (C) from the environment via a supply air path (7), wherein the mixing air element (5) is further configured to vary the ratio of recirculated airflow to exhaust airflow (B). The clothes dryer (0) is characterized by a control element (8) configured to regulate the ratio of recirculated airflow to exhaust airflow (B) by means of the mixing air element (5), preferably exclusively, depending on a setpoint temperature of the process airflow (A).