Spray arm for a dishwasher
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Solution Overview
Problem
Conventional dishwasher spray arms with conical nozzles face issues such as residual spraying during manufacturing, which affects the intended water jet configuration, and require increased installation space for inclined nozzle orientations, leading to higher water and energy consumption.
Innovation Solution
The design incorporates a through-flow space connected to the nozzle chamber, with a through-flow opening that defines the tear-off edge, allowing for an undisturbed fluid jet formation and enabling inclined nozzle configurations without additional space or components, by separating the nozzle outlet and through-flow openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conical nozzle is used in the spray arm, then the nozzle has reduced clogging tendency due to constricted water jet, but residual spraying occurs during manufacturing that interferes with the intended water jet configuration
Solution Approach 1:
The patent extracts the harmful tear-off edge from the nozzle outlet by introducing a through-flow chamber. The through-flow opening is positioned downstream of the nozzle outlet opening, effectively removing the problematic edge that causes residual spraying during injection molding. This allows the nozzle to maintain its conical shape for clogging resistance while eliminating the manufacturing defect that interferes with water jet configuration.
Solution Approach 2:
The through-flow chamber acts as an intermediary element between the nozzle chamber and the external environment. It provides a controlled flow path that separates the nozzle outlet opening from the tear-off edge, allowing the water jet to form correctly without interference from manufacturing residues. The through-flow opening serves as a mediator that guides the flow while preventing direct contact with the problematic edge.
2Manufacturing precision
If the nozzle is oriented inclined to achieve optimized jet formation, then the water jet configuration is improved, but increased installation space is required which reduces the total number of spray nozzles per spray arm
Solution Approach 1:
The patent resolves the space conflict by transitioning from a two-dimensional nozzle outlet to a three-dimensional through-flow chamber. The through-flow opening is positioned downstream in the flow direction, allowing the nozzle outlet opening to be inclined for optimized jet formation while the tear-off edge remains at a different spatial location. This dimensional separation enables inclined nozzle orientation without proportionally increasing the installation footprint.
Solution Approach 2:
The through-flow chamber is nested within the existing nozzle structure, utilizing the available space efficiently. By placing the through-flow opening downstream within the same general nozzle volume, the design achieves inclined jet formation without requiring additional external space that would reduce the number of nozzles per spray arm.
3Device complexity
If the nozzle outlet opening and tear-off edge are positioned at the same location, then the structure is simplified, but residual spraying occurs that cannot be avoided due to the demolding direction of the injection molding tool
Solution Approach 1:
The patent segments the nozzle structure into distinct functional zones: the nozzle outlet opening for water jet formation and the through-flow opening for defining the tear-off edge. This segmentation separates the functions of water discharge and manufacturing ejection, allowing the tear-off edge to be positioned downstream where it cannot interfere with the water jet configuration, while maintaining a relatively simple overall structure.
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 configuration achieves optimized jet formation and allows for inclined nozzle orientations without increased space requirements, reducing clogging tendencies and energy consumption, while maintaining a clean, planar outer surface.
Implementation Method 1
the conical shape of the nozzle leads to a constriction of the water jet formed by the nozzle when used as intended. This in turn means that the hydraulic diameter of the water jet is smaller than the geometric diameter of the nozzle outlet opening
Implementation Method 2
A fluid flowing through the nozzle when used as intended therefore first reaches the nozzle chamber on the inlet side, from where it reaches the through-flow chamber adjoining the nozzle chamber. This provides an outlet opening on the nozzle outlet side, through which the fluid leaves the nozzle.
Data Source
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AI summary
The invention relates to a spray arm for a dishwasher, comprising a base body (21) made at least partially of plastic and a nozzle (27) which is integrally formed with the base body (21), wherein the nozzle (27) has a nozzle chamber (30) and a flow chamber (40) downstream of the nozzle chamber (30) in the direction of flow through the nozzle (39), which is directly connected to the nozzle chamber (30) by means of a flow opening (41).