Dryer Air Duct Blockage Detection Using Motor Power Drop
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Solution Overview
Problem
Existing dryers fail to detect partial blockages in the process air duct early and efficiently, leading to reduced drying effectiveness, extended cycle times, and potential overheating, as current methods rely on expensive pressure sensors, temperature monitoring, or additional sensors that alert users too late in the cycle.
Innovation Solution
An evaluation circuit determines the power consumption of the motor and detects a partial blockage by identifying a drop in power, with the option to set a predetermined limit value that accounts for temperature-dependent air density and fan efficiency, allowing for early detection of air throttling and prompting users to clean filters during the program.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature monitoring is used to detect blockages, then blockage detection is achieved, but detection occurs too late in the program cycle
Solution Approach 1:
The patent applies preliminary action by evaluating motor power consumption early in the drying program, before temperature-based methods would detect blockages. The control device continuously monitors motor power from the start of the program, enabling early blockage detection when the filter is first becoming clogged, rather than waiting for temperature changes to indicate severe blockage later in the cycle.
2Reliability
If pressure sensors are used for differential pressure measurement, then blockage detection is achieved, but production cost increases
Solution Approach 1:
The patent applies self-service by using the motor's own power consumption data to detect blockages. The control device utilizes existing motor current and voltage measurements that are already available for motor control, eliminating the need for additional pressure sensors. The motor essentially monitors itself through its electrical characteristics, reducing system complexity and production costs.
3Reliability
If additional sensors are added for speed or temperature monitoring, then blockage detection capability is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by making the motor serve multiple functions: it drives the process air fan for air circulation and simultaneously acts as a sensor through its power consumption measurements. The existing motor control circuitry that measures current and voltage for speed control is also used for blockage detection, eliminating the need for separate sensors and reducing device complexity.
4Loss of time
If motor power evaluation is used for blockage detection, then early detection is achieved with simple means, but power measurement accuracy must be sufficient
Solution Approach 1:
The patent applies feedback by continuously monitoring motor power consumption and comparing it against reference values or thresholds. The control device uses the measured motor current and voltage to calculate real-time power consumption, providing continuous feedback on air duct conditions. This enables dynamic detection of blockages as they develop, with the system responding to gradual changes in power consumption patterns.
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 method allows for early detection of air duct blockages, independent of laundry quantity and temperature evaluation, enabling timely filter cleaning and preventing overheating, thus improving dryer efficiency and user awareness.
Implementation Method 1
an evaluation circuit determines the power consumed or output by the motor and recognizes an at least partial blockage of the process air duct due to a drop in power
Implementation Method 2
process air is supplied and/or discharged to and/or from a drum rotatably mounted as a drying chamber by means of a process air fan through the process air duct
Implementation Method 3
a motor for Drive of the process air fan is at least switched on and off by a control device and/or is influenced with regard to its speed
Data Source
Figure 1
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Figure 4~5
AI summary
The invention concerns a procedure for recognizing a partial constipation of a process air channel (7) in a dryer (1), in which zu and/or from a drying chamber (2) by means of a process air blade (8) by the process air channel (7) process air (6)) to be derived and/or derived and in which an engine (4) to drive the process air blade (8) by a control device (12) is at least switched on and off, possibly also influenced with regard to its speed.In order to indicate at least partially constipation of the process air channel, in particular a due cleaning of the sieves, it is suggested that an evaluation circuit (14) determines the performance recorded or cast from the engine (14) and at least partially blocked due to a performance dropof the process air channel (7) recognizes.