Conical Gap Foaming Device for Adjustable Milk Foam Stability

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Solution Overview

Problem

Existing devices for foaming liquids, such as milk, fail to produce high-quality foam that is stable and maintains volume effectively due to limitations in controlling foam stability based on milk viscosity and temperature, primarily due to inconsistent shear stress and speed variations.

Innovation Solution

A device with a conical cavity and wheel design that allows for adjustable gap width and linear speed control, enabling precise control over foam stability by varying the gap width and rotation speed to match the characteristics of the liquid being foamed, using a Taylor-Couette flow mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the speed of the cylinders rotating with respect to each other is changed, then the foaming level can be adjusted, but the good quality of the milk foam cannot be ensured as a function of the characteristics of the milk being used

Engineering Contradiction:
Improvefoaming levelVSAvoidfoam quality stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by adjusting the gap width between the inner and outer cylinders in addition to rotation speed. This allows optimization of shear stress conditions according to milk characteristics (viscosity, temperature) while maintaining consistent foam quality across different operating conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The device enables dynamic adjustment of both rotation speed and gap width, allowing the foaming process to adapt to different milk types and temperatures. This dynamic control ensures that optimal shear stress conditions can be maintained regardless of milk characteristics

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the gap width between the inner and outer cylinders is fixed, then the device structure is simple, but the foam quality cannot be optimized for different milk characteristics

Engineering Contradiction:
Improvedevice structureVSAvoidadaptability to different milk characteristics
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The gap width is made adjustable rather than fixed, allowing the device to adapt to different milk characteristics such as viscosity and temperature. This dynamic adjustment capability enables optimization of shear stress conditions without significantly complicating the overall device structure

Inventive Principle:
Principle #15Dynamics

3Productivity

If the rotation speed is increased to achieve higher foaming level, then the foam production increases, but the foam quality becomes inconsistent

Engineering Contradiction:
Improvefoam productionVSAvoidfoam stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent changes the approach by adjusting both rotation speed and gap width together to optimize shear stress. This combined parameter adjustment allows achieving high foaming levels while maintaining consistent foam stability, rather than relying solely on increasing rotation speed

Inventive Principle:
Principle #35Parameter changes

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 device achieves stable and high-quality foamed beverages by ensuring consistent shear stress and adjustable foaming levels, suitable for various liquid viscosities and temperatures, resulting in improved foam texture and stability.

Implementation Method 1

the milk-air mixture passes, at least partially, through the device with Taylor-Couette flow

Methodology Applied
Scientific EffectTaylor-Couette flow: Couette Flow

Implementation Method 2

the milk-air mixture in the gap experiences high shear stress. The shear stress, which is achieved by designing the device so that the milk-air mixture passes, at least partially, through the device with Couette flow, leads to an emulsion of air and milk

Methodology Applied
Scientific EffectShear stress: Shear Stress

Data Source

PatentEP3270749B1Foaming device and corresponding method
Publication Date: 2019.11.20 RANCILIO GROUP SPA
  • EP3270749B1 patent drawingFigure 1~2
  • EP3270749B1 patent drawingFigure 3~4
  • EP3270749B1 patent drawingFigure 5~6

AI summary

Device for foaming a liquid comprising a mixing unit (30). The mixing unit (30) comprises a first element (31) having an inner surface (33), a second element (34) having an outer surface (35), a gap (36) between the inner surface (33) of the first element (31) and the outer surface (35) of the second element (34), a first opening (37) and a second opening (38) connected through the gap (36). At least one of the first element (31) or the second element (34) is rotatable about an axis of rotation (AR) with respect to the other one. The inner surface (33) and the outer surface (35) are symmetric with respect to a common axis of symmetry (AH, AW), coincident with the axis of rotation (AR), and have circular sections, perpendicularly to the axis of symmetry, having diameters which increase going in a direction along the axis of symmetry (AH, AW).