Tumble Dryer Ambient Temperature Sensing for Lint Filter Detection
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Solution Overview
Problem
Existing tumble dryers face challenges in reliably determining the degree of soiling of the lint filter, as methods based on drying time and heat pump compressor cycles can be influenced by ambient temperature, leading to inaccurate assessments.
Innovation Solution
Incorporating an ambient temperature sensor to control the drying process and display, allowing for differentiated operation of the heat pump and cooling fan, and using this temperature data to refine the determination of lint filter soiling by considering process duration, temperature parameters, and overheating cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drying time is used to determine lint filter soiling, then the method is simple to implement, but the determination becomes inaccurate when ambient temperature varies
Solution Approach 1:
The patent replaces the simple time-based mechanical determination method with a temperature-compensated electronic control system. The controller uses temperature sensor data to adjust the evaluation of drying time, substituting the purely mechanical time measurement with an electronic system that incorporates environmental compensation to achieve accurate soiling determination.
Solution Approach 2:
The patent changes the evaluation parameter from fixed time duration to temperature-compensated time duration. By introducing ambient temperature as a variable parameter, the system adjusts the expected drying time based on environmental conditions, allowing accurate lint filter soiling determination that accounts for temperature variations.
2Measurement precision
If heat pump compressor overheating cycles are used to determine lint filter soiling, then the method provides operational data, but the indication becomes unreliable due to ambient temperature influence
Solution Approach 1:
The patent replaces the direct observation of compressor overheating cycles with a temperature-compensated evaluation system. Instead of simply counting overheating events, the controller uses temperature sensor data to contextualize these events, distinguishing between overheating caused by ambient temperature versus overheating caused by lint filter blockage.
Solution Approach 2:
The patent introduces ambient temperature data as an intermediary parameter between the compressor operation and the soiling determination. This intermediary information allows the controller to interpret compressor overheating cycles in context, filtering out false indications caused by environmental temperature variations.
3Reliability
If process time is extended to ensure thorough drying, then drying completeness is improved, but energy consumption increases
Solution Approach 1:
The patent makes the drying process duration dynamic rather than fixed. The controller continuously monitors ambient temperature and adjusts the drying time accordingly, extending the process only when temperature conditions require it to ensure complete drying, rather than using a conservative fixed duration for all conditions.
Solution Approach 2:
The patent changes the process time parameter from a fixed value to a temperature-dependent variable. By adjusting the drying duration based on ambient temperature measurements, the system optimizes energy consumption while maintaining drying completeness, avoiding unnecessary extended operation in favorable temperature 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
This approach provides a more accurate assessment of lint filter soiling and improves the estimation of drying process time, energy consumption, and optimal process temperatures, enhancing the overall efficiency and user information in tumble dryers.
Implementation Method 1
the controller (8) is designed to determine the ambient temperature using a temperature sensor
Implementation Method 2
a heat pump being provided for drying and heating the process air
Implementation Method 3
a cooling fan to cool part of the heat pump with ambient air and thus extract excess heat from the device
Implementation Method 4
The evaporator (6) is used to cool the process air and to remove water from it
Data Source
Figure 1
AI summary
A temperature sensor (20) is provided in a tumble dryer, with which the ambient temperature can be determined. The ambient temperature can be used, for example, to cool the heat pump (2, 3, 5, 6) of the device as required, to estimate the expected process time more precisely, to more reliably detect soiling of the lint filter (12) or to define various parameters of the drying process.