Dishwasher Drain Pump Vanes That Retract During Wash Cycles
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Solution Overview
Problem
Conventional dishwasher appliances using a single motor and common drive shaft for both wash and drain pumps face issues with the drain pump impeller pumping fluid during wash cycles due to reverse rotation, necessitating complex valve systems or increased motor load.
Innovation Solution
A drain pump assembly with a hub-mounted vane system that rotates between extended and retracted positions, utilizing a biasing member to counteract centrifugal force, ensuring no fluid pumping during wash cycles while allowing drainage during drain cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single motor and common drive shaft are used to rotate both wash pump and drain pump impellers, then cost and complexity are reduced, but the drain pump impeller pumps fluid during wash cycles when rotated in reverse direction
Solution Approach 1:
The drain pump impeller is designed with movable vanes that can change their orientation dynamically based on rotation direction. During wash cycles (reverse rotation), the vanes fold back against the rotation to prevent fluid pumping. During drain cycles (forward rotation), the vanes extend to enable fluid pumping. This dynamic adaptation resolves the contradiction by allowing the single motor system to perform both functions without unwanted fluid discharge.
Solution Approach 2:
The impeller vane configuration changes its geometric parameters based on operational mode. The vanes transition between extended and retracted positions, altering the impeller's effective shape and pumping characteristics. This parameter change enables the same physical component to exhibit different functional behaviors for washing and draining operations.
2Object-generated harmful factors
If complicated valve systems are used to prevent drain pump impeller from pumping fluid during wash cycles, then unwanted fluid discharge is prevented, but device complexity and cost increase
Solution Approach 1:
The invention extracts and eliminates the need for separate valve systems by integrating the fluid control function directly into the impeller structure itself. The movable vanes perform the function that would otherwise require external valves, simplifying the overall system while preventing unwanted fluid discharge during wash cycles.
Solution Approach 2:
The impeller becomes self-regulating through its movable vane mechanism. The vanes automatically adjust their position based on rotation direction and fluid pressure, controlling fluid flow without requiring external valve systems or additional control mechanisms. The impeller serves its own fluid control needs through its adaptive geometry.
3Object-generated harmful factors
If one-way clutches are used to prevent drain pump impeller from pumping fluid during wash cycles, then unwanted fluid discharge is prevented, but motor load increases
Solution Approach 1:
The invention converts the harmful effect of reverse rotation into a beneficial mechanism. The fluid pressure and centrifugal forces that would normally cause unwanted pumping are instead used to drive the vane movement and control fluid flow in the desired direction. The movable vanes utilize the rotational dynamics themselves to prevent harmful pumping during reverse rotation.
4Reliability
If two separate motors are used to operate wash pump and drain pump, then reliability is improved by having independent control, but device complexity, cost, and space requirements increase
Solution Approach 1:
The single motor and drive shaft system is designed to perform multiple functions - driving both the wash pump impeller and drain pump impeller. The movable vane mechanism enables the drain pump impeller to adapt its function based on rotation direction, allowing one motor system to reliably perform both washing and draining operations that would traditionally require separate motors.
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 solution prevents unwanted fluid discharge during wash cycles, reduces the need for complex valve systems, and decreases motor load, enhancing the reliability and efficiency of dishwasher operations.
Implementation Method 1
A biasing member is mounted to each vane for urging the vanes to the retracted position to counteract the centrifugal force exerted on the vanes during operation.
Data Source
AI summary
A dishwasher appliance is provided having a drain pump assembly including a hub mounted to a drive shaft that is driven in a first direction during a drain cycle and in a second direction during a wash/rinse cycle. One or more vanes are mounted to the hub and are rotatable between a retracted position during the drain cycle and an extended position during the wash/rinse cycle. A biasing member is mounted to each vane for urging the vanes to the retracted position to counteract the centrifugal force exerted on the vanes during operation. In this manner, the drain pump assembly pumps wash fluid during a drain cycle but does not pump wash fluid during a wash cycle.