Control method for laundry drying machine and laundry drying machine
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Solution Overview
Problem
Heat pump cycle type laundry drying machines face challenges in detecting filter plugging due to minimal temperature changes, leading to reduced drying performance, as existing methods relying on temperature sensors are not applicable.
Innovation Solution
A control method that senses the difference between the compressor outlet temperature and the drum outlet temperature to determine filter plugging, with a controller stopping the compressor and outputting a filter cleaning notification when a predetermined temperature difference is exceeded, and allowing selection of dry modes based on frequency and temperature settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are used to detect filter plugging, then filter plugging can be detected in heater type laundry drying machines, but this method cannot be applied to heat pump cycle type laundry drying machines due to minimal temperature changes
Solution Approach 1:
The patent changes the detection parameter from temperature difference to compressor running time. By monitoring how long the compressor has been running and comparing it against expected time ranges, the system can detect filter plugging in heat pump dryers without relying on temperature changes that don't occur in this dryer type.
Solution Approach 2:
Instead of detecting filter plugging through its direct effect (temperature change in heater type), the patent detects it through an indirect effect (compressor running time in heat pump type). This inversion of the detection approach allows the same functionality to work across different dryer types with different operating mechanisms.
2Productivity
If the compressor is driven at high frequency for fast drying, then drying performance is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic compressor frequency adjustment based on detected filter plugging conditions. The compressor frequency is changed from a fixed high value to a variable value that adapts to the actual drying state, allowing the system to maintain high productivity when needed while reducing energy consumption when the filter is plugged and drying efficiency is compromised.
Solution Approach 2:
The system changes the operating parameter of compressor frequency based on detected conditions. When filter plugging is detected, the compressor frequency is adjusted to an appropriate value, transforming the static high-frequency operation into a dynamic parameter that responds to system state, thereby optimizing the balance between productivity and energy consumption.
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
Accurate detection and notification of filter plugging, preventing reduced drying performance and minimizing power consumption by ensuring timely filter cleaning.
Implementation Method 1
a compressor (41) for compressing a refrigerant to a high-temperature and high-pressure vapor refrigerant
Implementation Method 2
a condenser (42) for condensing the refrigerant, compressed by the compressor, to a high-temperature and high-pressure liquid refrigerant
Implementation Method 3
an evaporator (44) for evaporating the refrigerant, expanded by the expansion valve, to a low-temperature and low-pressure vapor refrigerant
Implementation Method 4
sensing a compressor outlet temperature and a drum outlet temperature; and determining plugging of a filter, based on a difference between the compressor outlet temperature and the drum outlet temperature
Data Source
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AI summary
Control method for a laundry drying machine. The control method includes driving a compressor (41) configuring the heat pump cycle (40) for generation of heated air, sensing a compressor (41) outlet temperature (TE) and a drum outlet temperature (TD), and determining plugging of a lint filter, based on a difference between the compressor (41) outlet temperature (TE) and the drum outlet temperature (TD).