Dishwasher Discharge Pump Impeller for Solid Passage and Efficiency
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Solution Overview
Problem
Centrifugal discharge pumps in dishwashers face a trade-off between preventing blockages from contaminants and maintaining hydraulic efficiency, as existing designs with recessed impellers to avoid blockages result in low hydraulic efficiency, necessitating large and costly electric motors.
Innovation Solution
A centrifugal discharge pump with a rotatable impeller featuring a support element and blades that allow a free space along the main axis for solid removal, enabling close clearance with the chamber walls and using curved blades for improved hydraulic efficiency, combined with a synchronous electric motor for electronic control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a recessed impeller with straight blades is used to prevent blockages, then the pump can remove foreign solids easily, but the hydraulic efficiency becomes low
Solution Approach 1:
The patent applies curved blades instead of straight blades in the impeller design. The curved geometry of the blades optimizes fluid flow dynamics, thereby improving hydraulic efficiency while the recessed structure maintains blockage prevention capabilities
Solution Approach 2:
The patent creates different geometric characteristics in different parts of the impeller: the blades are curved to improve hydraulic efficiency, while the overall impeller structure remains recessed to prevent blockages. This local differentiation allows simultaneous optimization of both efficiency and reliability
2Reliability
If a recessed impeller is used to allow solid passage, then foreign solids can be removed without blockage, but larger and more powerful electric motors are required
Solution Approach 1:
The curved blade geometry improves hydraulic efficiency, which directly reduces the power requirements of the motor. This allows the pump to maintain solid removal capability while using a smaller, less powerful motor compared to recessed impeller designs with straight blades
3Ease of manufacture
If a recessed impeller with straight blades is used, then the structure is simple and easy to manufacture, but copper wear increases due to larger motor size
Solution Approach 1:
The curved blade design improves hydraulic efficiency, reducing the motor size and operational power requirements. This reduction in power and operational stress decreases copper wear in the motor, while the impeller remains relatively simple in structure with the recessed configuration
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 solution achieves high hydraulic efficiency while preventing blockages, reducing manufacturing costs and wear on active materials by allowing easy passage of solids and optimizing fluid direction with curved blades and electronic motor control.
Implementation Method 1
an impeller arranged inside the working chamber and rotatable about the aforementioned main axis so as to move a discharge stream of the electric household appliance
Data Source
AI summary
A centrifugal discharge pump (1) for electric household appliances, of unusual efficiency, having: a working chamber which has an intake opening and a delivery opening; an open impeller (10) arranged inside the working chamber and rotatable about a main axis (x) and a motor (5) designed to drive the impeller (10) by means of a transmission shaft (6). The impeller (10) has a planar support element (11) integral with the transmission shaft (6), and a plurality of blades (12) projecting from the support element (11); a free space (13) is provided between the blades (12) in order to allow the removal of foreign solids present in the discharge stream.