Laundry treatment device and method for operating same
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Solution Overview
Problem
Conventional laundry treatment appliances face inaccuracies in moisture detection during drying processes, especially in high humidity environments, due to the limitations of moisture sensors.
Innovation Solution
A laundry treatment appliance with a process air circuit equipped with temperature and humidity sensors, where the drying process is controlled based on the deviation of the instantaneous water loading from a determined maximum, independent of the absolute humidity measurement, allowing for precise moisture level detection and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If moisture sensors are used to detect the moisture level of laundry during drying, then the drying process can be monitored, but the measurement accuracy deteriorates in high humidity areas
Solution Approach 1:
The patent introduces process air as an intermediary medium to transfer moisture information from the laundry to the sensors. Instead of placing sensors directly in contact with laundry or in high-humidity zones, the system circulates process air through the laundry load and measures its moisture content upstream of the condensation device, where humidity levels are more manageable and measurement accuracy is maintained.
Solution Approach 2:
The patent replaces direct contact moisture sensors with indirect measurement using temperature and humidity sensors that detect the state of process air. This substitution allows measurement of moisture content through air parameters (temperature and relative humidity) rather than direct electrical resistance measurement, improving reliability in high humidity conditions.
2Measurement precision
If moisture sensors operate in high humidity areas, then they can detect laundry moisture directly, but sensor durability and measurement consistency deteriorate over time
Solution Approach 1:
The system uses process air as a mediator to carry moisture information from the laundry to the measurement zone. The temperature and humidity sensors measure the air's moisture content upstream of the condensation device, avoiding direct exposure to extreme humidity conditions that would compromise sensor reliability and measurement consistency.
Solution Approach 2:
The system performs preliminary measurement of process air parameters (temperature and relative humidity) upstream of the condensation device, where conditions are more stable. This preliminary action allows determination of water loading before the air enters the high-humidity condensation zone, ensuring consistent and reliable measurements throughout the drying process.
3Extent of automation
If the drying process is controlled based on absolute humidity measurement, then the control system can regulate drying, but the control accuracy deteriorates due to sensor measurement deviations
Solution Approach 1:
The system implements feedback control by continuously measuring temperature and relative humidity of the process air upstream of the condensation device, determining the water loading, calculating the deviation from maximum water loading, and using this information to control the drying process. This feedback loop maintains control accuracy despite variations in absolute humidity measurements.
Solution Approach 2:
The patent changes the control parameter from absolute humidity to the deviation of water loading from its maximum value. By controlling based on this deviation parameter rather than absolute humidity, the system achieves more accurate and reliable drying control that is independent of sensor measurement deviations and drift over time.
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 enables more accurate and reliable drying process control, independent of sensor measurement accuracy and drift over time, ensuring consistent dryness of laundry.
Implementation Method 1
at least one temperature sensor arranged on the process air circuit for detecting a temperature of the process air
Implementation Method 2
at least one humidity sensor arranged on the process air circuit for detecting a relative humidity of the process air
Data Source
Figure 1
AI summary
The invention relates to a laundry treatment appliance (1), having at least one process air circuit (2) in which process air can be circulated during a drying process for drying laundry in the process air circuit (2), at least one temperature sensor (6 ) for detecting a temperature of the process air, at least one humidity sensor (7) arranged on the process air circuit (2) for detecting a relative humidity of the process air and at least one electronic unit (8) connected to the temperature sensor (6) and the humidity sensor (7). In order to create a laundry treatment appliance (1) with which, in order to improve a drying process that can be carried out with the laundry treatment appliance (1), a more precise detection of the moisture level of laundry to be dried is possible, it is proposed that the electronic unit (8) be set up to switch off during the drying process the measured temperature and the measured relative humidity to determine a water loading of the process air, to determine a maximum of the water loading of the process air, to determine a value of a deviation of the instantaneous water loading from the maximum of the water loading and to generate a switch-off signal to end the drying process if the Value of the deviation reaches a predetermined limit.