Dishwasher Passage Switching Valve Timing for Noise Reduction
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Solution Overview
Problem
Dishwashers experience noise issues due to pressure variations generated when rotating the passage switching valve between upper and lower water passages, which existing solutions attempt to mitigate by reducing the rotational speed of the washing motor or pump, but these methods may compromise wash performance.
Innovation Solution
A method that involves reducing the rotational speed of the wash pump before rotating the passage switching valve and returning it to the original speed once the valve has completed its rotation, ensuring the passage switching is synchronized with the reduced pump speed to minimize noise while maintaining wash performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the passage switching valve is rotated to switch the water passage between upper and lower nozzles, then the water supply to different nozzles is controlled, but noise is generated due to pressure variation
Solution Approach 1:
The control unit reduces the rotational speed of the wash pump before the passage switching valve rotates, in advance preparation to minimize pressure variation and noise during the switching operation
Solution Approach 2:
The rotational speed of the wash pump is dynamically adjusted based on the operational state of the passage switching valve, changing the speed parameter from high to low during valve rotation and back to high after switching is complete
2Object-generated harmful factors
If the rotational speed of the wash pump is reduced during passage switching, then noise is minimized, but wash performance may be compromised
Solution Approach 1:
The wash pump operates at reduced speed only during the brief period when the passage switching valve is rotating, then returns to high speed for the majority of the washing cycle, achieving noise reduction without compromising overall wash performance
Solution Approach 2:
The pump speed is reduced in advance of the valve switching operation and restored after switching is complete, ensuring that the high-speed washing function is maintained for the maximum possible duration
3Reliability
If the passage switching valve is rotated while the wash pump operates at high speed, then wash performance is maintained, but noise is generated due to pressure variation
Solution Approach 1:
The control unit monitors the rotational position of the passage switching valve and adjusts the wash pump speed accordingly, creating a feedback control system that coordinates pump speed with valve position to minimize noise
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 effectively reduces noise generated by the passage switching valve while maintaining the original wash pump speed, ensuring consistent wash performance by coordinating the pump speed reduction with the valve's rotation timing.
Implementation Method 1
A passage switching valve, for turning on/off the upper/lower passage by blocking the upper/lower passage selectively, is provided to a diverging portion between the upper and lower passages.
Implementation Method 2
A wash pump for pumping supplied water to the upper and lower nozzles is provided to the sump.
Implementation Method 3
a dishwasher is a device for washing tableware in a manner of spraying high-pressure water into a washtub to separate particles such as leftover food attached to a surface of tableware from the tableware
Data Source
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AI summary
A dishwasher and controlling method thereof are disclosed, by which noise generated from rotation of a passage switching valve can be reduced in a manner of adjusting a rotation timing point of the passage switching valve and a rotation speed of a wash pump. The embodiments describe rotating a passage switching valve for switching a passage to selectively supply water to either an upper nozzle or a lower nozzle and reducing a rotational speed of a wash pump supplying the water to the upper and lower nozzles before the rotation of the passage switching valve.