Coffee Dispensing Spout Geometry for Splash-Free Foam Flow
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Solution Overview
Problem
Existing coffee machines face issues with turbulence and splashing during coffee infusion, leading to overflow and clogging, and struggle to produce fine and persistent coffee foam that flows correctly, often causing foam to stick to the walls and slow down the coffee flow.
Innovation Solution
A coffee machine with a pouring spout featuring an end wall with an open contour passage section, oriented tangentially to the infusion jet, ensuring a laminar flow and preventing foam agglomeration, combined with an oblique zone and smooth transitions to maintain a continuous and regular flow without turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a narrow passage section is used in the outlet spout, then lateral overflows and splashing are prevented, but the spout becomes prone to clogging and scaling requiring repeated cleaning
Solution Approach 1:
The outlet spout incorporates a curved trajectory for the infusion jet, transitioning from a straight narrow passage to a curved path that follows the spout contour. This curvature prevents direct impact against the spout walls, reducing turbulence and splashing while maintaining a larger effective passage area that resists clogging. The curved geometry allows the liquid to flow smoothly along the wall without creating high-velocity jets that cause harmful splashing.
Solution Approach 2:
The outlet spout is divided into multiple functional zones: an upper section with a first curvature radius for initial flow direction control, a lower section with a second curvature radius for final flow redirection, and intermediate transition zones. This segmentation allows each section to be optimized for specific functions - the upper section controls the jet formation while the lower section ensures smooth discharge, preventing both overflow and clogging in different regions.
2Object-affected harmful factors
If cylindrical outlet pipes with narrow closed passage section are used, then lateral overflows are prevented, but foam sticks to the walls and does not descend rapidly, causing accumulation and overflow
Solution Approach 1:
The curved trajectory of the outlet spout creates a flow path that follows the wall contour, allowing foam to descend along the curved surface rather than sticking to a straight cylindrical wall. The curvature generates a centrifugal effect that prevents foam accumulation and promotes rapid descent. The open contour at the lower end further facilitates foam discharge by eliminating the closed cylindrical constraint that causes foam to stick.
Solution Approach 2:
Instead of using a closed cylindrical passage that confines the foam, the invention uses an open contour at the lower end of the spout. This inversion of the closed geometry allows foam to escape more easily. Additionally, the curvature direction is chosen to promote downward flow along the wall, counteracting the natural tendency of foam to stick to vertical surfaces.
3Adaptability or versatility
If a two-way pouring spout with V-shaped bowls is used, then coffee can be distributed to two cups, but turbulence and lateral acceleration cause overflow and droplet projections
Solution Approach 1:
The outlet spout uses a curved trajectory with carefully selected radius ratios to guide the infusion jet smoothly from the central duct to the collection container. The curvature prevents sharp directional changes that would cause turbulence. When distributing to multiple cups, the curved path allows the jet to follow the spout wall contour, maintaining laminar flow and preventing droplet projections even during lateral distribution.
Solution Approach 2:
Different sections of the outlet spout have different curvature radii optimized for their specific functions. The upper section has a larger radius for gentle flow direction control, while the lower section has a smaller radius for precise flow positioning. This local optimization allows the spout to maintain laminar flow throughout the distribution process, preventing turbulence at critical locations.
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 enables a rapid, continuous, and regular flow of coffee and foam into a collecting vessel without splashing or clogging, while being easy to clean and maintaining an aesthetic appearance.
Implementation Method 1
the rear upper part of which is arranged tangentially to the surface of the infusion jet which flows over said end wall... capable of channeling the infusion obtained towards at least one collecting container located below, so as to allow a rapid, but continuous and regular flow, without turbulence
Implementation Method 2
it was observed during the tests carried out that due to the phenomena of good wetting of the coffee infusion in contact with the internal surface of the spout, the coffee infusion flows quickly along the wall end of the spout
Data Source
Figure 1
Figure 2a~2c
Figure 3a~3b
AI summary
The machine has a cold water tank communicating with a thermal block, enclosing a water circuit and an electric heating element, supplying hot water to an infusion chamber containing coffee grounds and to a foaming device. The chamber is in fluid communication with a discharge pipe (11) extended by a spout (10). The spout has an end wall (12) whose rear upper part is arranged tangentially to the surface of the infusion jet which flows on the wall until the wall`s lower part reaches the height of a collecting vessel. The wall has a slit (35) with open outline, oriented rearwards of the machine.