Condensation Dryer Time-Based Moisture Detection Without Drum Sensors
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Solution Overview
Problem
Current condensation dryers lack precise control over the transition from the stationary to the transient phase in the drying process, which affects moisture level determination and energy efficiency, and fail to accurately determine the load of laundry early in the drying process.
Innovation Solution
A method using a condensation dryer with a process air duct, drum, heat exchanger, liquid sensor, and time measuring device to evaluate the time required for condensation of a predetermined amount of water, forming a quotient from subsequent time periods to determine the transition between phases and adjust the drying process accordingly, without the need for moisture or temperature sensors in the drum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If condensation dryers use traditional temperature and humidity sensors in the drum to determine moisture levels, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the measurement function from the drum interior to the condensate collection system. Instead of placing sensors inside the drum to measure laundry moisture directly, the system measures the condensation rate of water vapor extracted from the laundry indirectly. This removes complex sensors from the drum while achieving the same measurement objective through a different location and method.
Solution Approach 2:
The patent introduces condensation water as an intermediary medium between the laundry and the measurement system. Rather than measuring laundry moisture directly with sensors in the drum, the system measures the rate at which water vapor from the laundry condenses into liquid water in the heat exchanger and condensate pan. This intermediary measurement approach simplifies the sensor requirements while maintaining measurement accuracy.
2Measurement precision
If condensation dryers use multiple sensors to monitor the drying process, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the liquid level sensor in the condensate pan perform multiple functions: it measures both the amount of condensation produced (indicating moisture removal rate) and indirectly determines the transition between stationary and transient phases. This multi-functional use of a single simple sensor replaces what would traditionally require multiple specialized sensors distributed throughout the drying system.
Solution Approach 2:
The system uses the condensation water itself as the measurement medium. The liquid level sensor detects the accumulation of condensation water, and the control unit calculates condensation rate from this data. The system essentially measures itself through the natural condensation process, eliminating the need for separate measurement devices in the drum and air flow paths.
3Productivity
If the drying process uses a simple timer-based control, then device complexity is reduced, but productivity and energy efficiency deteriorate
Solution Approach 1:
The patent implements feedback control by continuously monitoring the condensation rate through the liquid level sensor and using this information to dynamically adjust the drying process. The control unit detects when the system transitions from stationary to transient phase based on changes in condensation rate, and automatically adjusts heating power and airflow accordingly. This feedback mechanism replaces simple timer-based control, improving energy efficiency and productivity despite increased control complexity.
Solution Approach 2:
The patent makes the drying process dynamic by adjusting operational parameters in real-time based on measured condensation rates. Rather than using fixed timer schedules, the system continuously adapts heating power, airflow rate, and cycle duration based on the actual moisture removal rate. This dynamic control optimizes energy consumption and drying speed according to the specific load conditions.
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
Enables precise determination of laundry moisture levels and load, allowing for gentle and energy-efficient drying, with the ability to adjust the drying process based on the measured condensation rates, improving the accuracy of the drying process and reducing energy consumption.
Implementation Method 1
a heat exchanger for condensing water from warm, humid process air
Implementation Method 2
The cool process air is generally conducted through a fan over a heater. The warm, dry process air then enters the drum
Implementation Method 3
The cool process air is generally conducted through a fan over a heater
Implementation Method 4
Drying processes using the condensation method are based on the evaporation of moisture from items of laundry using warm process air
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for operating a condensation dryer (1) comprising a process air channel (2), a drum (3) with items of laundry placed therein, a heat exchanger (15) for condensing water from moist warm process air, a liquid sensor (11) in a condensate tub (17), a time measuring device (5) and a control device (10), wherein the time measuring device (5) measures at least one time period (Δtn), where n is ≥ 1, which is required for condensing a prespecified quantity m=mset1 of water from the moist warm process air, and is said time period is evaluated in order to determine at least one property of the items of laundry, wherein, for evaluation purposes, a relationship, which is stored in the control device (10), between Δtn and the at least one property is used, and wherein a quotient (Q) is formed from the ratio of a time period (Δtn) and a subsequent time period (Δtn+1), so that Q=(Δtn+1/Δtn), and the method is carried out until Q is > 1, as a result of which a transition between a stationary phase and a non-stationary phase is indicated. The invention also relates to a condensation dryer which is suitable for performing said method.