Dishwasher and relevant operating cycle
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Solution Overview
Problem
Existing dishwashers face challenges in efficiently cleaning the hydraulic circuit without cooling the wash tank and dishes during an intermediate rinse, leading to increased energy consumption and water usage, while prior solutions either risk contamination or require complex and costly valve systems.
Innovation Solution
A dishwasher with a recirculation duct and a shut-off valve between the delivery duct of the wash pump and the sump allows for an intermediate rinse focused on critical areas, preventing backflow and reducing water consumption by circulating water only within the hydraulic circuit for cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intermediate rinse with cold water is performed to clean the hydraulic circuit, then the cleanliness of the hydraulic circuit is improved, but the wash tank and dishes are cooled requiring additional heating energy
Solution Approach 1:
The hydraulic circuit is segmented into two zones: the wash tank containing dishes (kept hot) and the hydraulic circuit components (cooled during intermediate rinse). The recirculation system enables selective cooling of only the hydraulic circuit by circulating cold rinse water through pumps and pipes while excluding the wash tank, thus maintaining dish temperature without compromising circuit cleanliness.
Solution Approach 2:
Different temperature zones are created within the system: the wash tank maintains high temperature for dish washing, while the hydraulic circuit undergoes localized cooling during intermediate rinse. This local quality differentiation allows the intermediate rinse to clean the circuit without necessarily cooling the entire system including the dishes.
2Reliability
If a two-way valve is used to prevent backflow of wash liquid into the mains water line, then contamination is prevented, but the device complexity and cost increase
Solution Approach 1:
Instead of using a complex two-way valve to prevent backflow, the invention inverts the approach by using the wash pump itself as a one-way barrier. The pump's operational direction creates natural pressure differential that prevents backflow into the mains water line, eliminating the need for additional valve mechanisms while maintaining contamination prevention.
Solution Approach 2:
The wash pump performs dual functions: it circulates water during washing and simultaneously acts as a backflow prevention device during intermediate rinse. The pump's own operational characteristics (directional flow, pressure generation) provide the protection against contamination without requiring external protective devices.
3Reliability
If water is immediately discharged by the drain pump after entering the sump, then the hydraulic circuit is cleaned efficiently, but water consumption increases
Solution Approach 1:
The recirculation system maintains continuous useful action by circulating the same volume of rinse water multiple times through the hydraulic circuit components. Instead of single-pass discharge, the water is pumped through pipes and pumps repeatedly, ensuring thorough cleaning of all critical areas while minimizing water consumption through repeated use of the same water volume.
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 enables a more efficient and cost-effective intermediate rinse that maintains cleanliness without cooling the wash tank and dishes, reducing energy consumption and water usage, while simplifying the hydraulic circuit and reducing component costs.
Implementation Method 1
due to the pressure of the wash pump during normal operation, the wash liquid can flow back into the mains water line
Implementation Method 2
a recirculation duct extending between the delivery duct of the wash pump and the sump
Implementation Method 3
DE 102017129052A1 describes a dishwasher equipped with a mains water supply line controlled by a two-way valve
Data Source
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AI summary
A dishwasher includes a load valve (1) that controls the inflow of water from the mains through a load duct to load water into a bottom sump (4) through an inlet (5), a wash pump (7) that draws water from the bottom sump (4) through a suction duct (9) and sends it to a plurality of sprayers (10, 11) through a delivery duct (12) and a diverter valve (18), a drain pump (13) connected to a drain duct (14) so as to discharge water from the bottom sump (4), and a recirculation duct (15), provided with a shut-off valve (16), extending between the delivery duct (12) and an additional inlet (17) of the bottom sump (4).