Washer Overflow Switch Circuit for Low-Standby Power Drain Control
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Solution Overview
Problem
Laundry washing machines face inefficiencies in overflow detection systems that consume excessive electric power during standby states, as existing solutions do not effectively manage power usage when no overflow is detected.
Innovation Solution
An overflow control system utilizing a switching unit and detection unit, where the switch configures to a closed state only when the washing liquid level exceeds a threshold, allowing the drain pump to be activated independently of the microcontroller, using a TRIAC driving apparatus and a detection circuit generating distinct signals for open and closed configurations to manage power efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a float switch detection system is continuously monitored, then overflow detection reliability is improved, but electric power consumption increases during standby states
Solution Approach 1:
The microcontroller monitors the float switch in a periodic interrupt-driven manner rather than continuously. The interrupt service routine is triggered only when the float switch state changes, allowing the system to maintain reliable overflow detection while entering low-power sleep modes during normal operation, thus reducing overall power consumption.
Solution Approach 2:
The system uses the existing float switch mechanism to automatically trigger the drain pump when overflow is detected, without requiring continuous microcontroller intervention. The electrical connection between the float switch and drain pump creates an automatic response system that reduces the burden on the microcontroller and allows it to enter power-saving states.
2Speed
If the drain pump is activated automatically upon overflow detection, then response speed is improved, but system complexity increases due to independent pump control
Solution Approach 1:
The control system is segmented into two independent pathways: a fast automatic pathway that directly connects the float switch to the drain pump for immediate overflow response, and a controlled pathway that allows the microcontroller to manage the pump during normal washing operations. This segmentation enables both fast automatic response and controlled operation without requiring complex integration logic.
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
The system efficiently manages power consumption by only activating when an overflow is detected, reducing energy usage during standby states and providing effective overflow management without requiring complex calibration or additional components.
Implementation Method 1
a float located in the portion of the laundry washing machine wherein washing liquid collects in the overflow condition (such as at the bottom of the casing) and provided with a switch adapted to be switched in accordance with the height of the float
Implementation Method 2
The drain pump - and the recirculation pump, if present - are selectively operable by means of proper driving devices, such as TRIACs (Triode for Alternating Current)
Data Source
AI summary
A laundry washing machine (100) is provided. The laundry washing comprises: - a washing tub (107) configured to be supplied with washing liquid for treating laundry; - a rotatable drum (110), in which laundry (112) to be washed can be loaded, mounted in the washing tub (107); - a drain pump (170) operable to selectively cause washing liquid located in the washing tub (107) to be discharged; - an overflow control system (193, 194; 193, 194') for detecting an occurrence of an overflow condition of the laundry washing machine (100) in which a level of washing liquid collected at the bottom of the laundry washing machine (100) is equal to or higher than a predetermined threshold, and for driving the drain pump (170) to discharge washing liquid from the washing tub (107) in case an overflow condition has been detected, the overflow control system (193, 194; 193, 194') comprising a switching unit (193) and a detection unit (194; 194'), wherein: - the switching unit (193) comprises a switch (420) having a first terminal connected to a terminal (TL) of an AC electric power supply and a second terminal connected to the detection unit (194; 194'), the switch (420) being configured to electrically connect the first terminal with the second terminal in a closed configuration and to electrically insulate the first terminal from the second terminal in an open configuration, the switching unit (193) being configured to switch the switch (420) to the closed configuration when the level of washing liquid collected at the bottom of the laundry washing machine (100) is equal to or higher than said predetermined threshold, and - the detection unit (194; 194') is configured to detect an overflow condition occurrence and to drive the drain pump (170) to discharge washing liquid from the washing tub (107) when the switch (420) is in the closed configuration.