Drain pump
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Solution Overview
Problem
Existing drain pumps in laundry treating apparatuses require separate motors for circulation and drainage, leading to space constraints and inefficiencies, with issues of backflow and cavitation noise due to excessive pressure reduction.
Innovation Solution
A drain pump design utilizing a single motor and impeller that switches rotational direction to perform both circulation and drainage functions, with a housing featuring separate discharge ports and a ribbed structure to prevent backflow and maintain optimal pressure, employing a BLDC motor for controlled speed and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate motors are used for circulation pump and drain pump, then each pump can operate independently, but the installation space is restricted and multiple motors increase cost
Solution Approach 1:
The patent combines the circulation pump and drain pump into a single integrated pump unit with one motor and one impeller. The housing includes a circulation water passage and a drain passage that are spatially separated, allowing the single impeller to perform both circulation and drainage functions by rotating in different directions, thereby reducing installation space and component count while maintaining independent operation capability
Solution Approach 2:
The single impeller is designed to perform multiple functions by switching rotational direction. When rotating in a first direction, it pumps water through the circulation water passage to the upper drum. When rotating in a second direction, it pumps water through the drain passage to the lower drum, making the same component universal for both circulation and drainage operations
2Area of stationary object
If the impeller rotational direction is switched to perform both circulation and drainage, then space is saved, but water flows backward toward undesired flow path
Solution Approach 1:
The housing is segmented into distinct flow paths: a circulation water passage and a drain passage. The circulation water passage includes a circulation water inlet and outlet positioned to receive water from the upper drum, while the drain passage includes a drain inlet and outlet for the lower drum. This spatial segmentation prevents cross-contamination of flow paths
Solution Approach 2:
The patent introduces a flow guide structure within the housing that acts as an intermediary to direct water flow. The flow guide includes a circulation water guide portion and a drain guide portion that separately channel water into the appropriate passages based on impeller rotation direction, preventing backward flow into undesired paths
3Reliability
If water inflow pressure is reduced to prevent backflow, then backflow is prevented, but cavitation occurs increasing noise
Solution Approach 1:
The patent employs dynamic control of the impeller rotation speed according to operating conditions. During drainage operation, the impeller rotates at a higher speed to maintain sufficient inflow pressure and prevent cavitation. During circulation operation, the impeller rotates at a lower speed. This dynamic speed adjustment allows the system to prevent backflow through proper flow path design while avoiding cavitation through adaptive speed control
Solution Approach 2:
The control unit monitors the operating mode (circulation or drainage) and adjusts the impeller rotation speed accordingly. This feedback control ensures that the pump operates at optimal speeds for each function, maintaining sufficient NPSH (Net Positive Suction Head) to prevent cavitation while achieving effective backflow prevention through the segmented flow path design
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
Enables efficient water management with reduced noise and power consumption by preventing backflow and cavitation, while maintaining effective drainage and circulation without space constraints.
Implementation Method 1
an impeller configured to form a flow of the water or wash water and rotate in a first direction or a second direction according to a rotation direction command signal from the controller so as to move the water or wash water toward the drain port or the circulation port
Implementation Method 2
If a water or wash water inflow pressure in the drain pump is excessively reduced to prevent a backflow of the drain pump, a cavitation phenomenon occurs in the drain pump, thereby increasing noise during the operation of the drain pump
Data Source
AI summary
The present disclosure relates to a drain pump for a laundry treating apparatus, including a housing configured to accommodate water; a water flow portion provided with an impeller forming a flow of water or wash water, and formed on an inner circumferential surface of the housing to circulate the accommodated water or wash water to a tub or drain the accommodated water or wash water out of a washing machine; a drain pump chamber formed on an inner circumferential surface of the housing to receive or store the water or wash water before the water or wash water flows into the water flow portion; and an inlet port formed to protrude toward the water flow portion between the water flow portion and the drain pump chamber.