Milk Foam Shear Gap Control for Continuous In-Line Foaming
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Solution Overview
Problem
Existing devices for producing milk foam are limited by batch processes, lack of in-line functionality, and unreliable foaming due to difficult-to-control factors such as geometry and steam temperature, resulting in inconsistent foam quality.
Innovation Solution
A device utilizing Couette flow between rotating cylinders to apply high shear energy to a milk-air mixture, allowing for continuous in-line foaming with controlled parameters like gap width, rotation speed, and exposure time to achieve consistent foam properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch process foaming devices are used, then foaming can be performed with simple structure, but productivity is limited and continuous in-line operation is not possible
Solution Approach 1:
The patent implements continuous in-line foaming by integrating the foaming device into a fluid flow path, allowing milk to be continuously pumped through the system. The device maintains continuous operation without batch emptying and refilling, with the pump continuously supplying milk through the foaming chamber and into the beverage preparation system.
2Adaptability or versatility
If steam injection method is used, then foaming can be achieved, but the device cannot be implemented in-line of fluid flow path
Solution Approach 1:
The patent extracts the foaming function from a separate batch process and integrates it directly into the fluid flow path. The foaming chamber is positioned within the continuous flow system, allowing foaming to occur in-line without requiring separate steam injection equipment or batch processing vessels.
3Reliability
If simple foaming device geometry is used, then device is easy to manufacture, but foaming properties are unreliable and inconsistent
Solution Approach 1:
The patent controls foaming reliability by precisely defining geometric parameters of the foaming chamber, including the gap width between rotating elements (0.1-1.0 mm), rotation speeds (1000-15000 rpm), and chamber dimensions. These controlled parameters ensure consistent shear stress application and reproducible foam quality across continuous operation.
4Ease of operation
If factors like whisk geometry and steam temperature are used to control foaming, then foaming can be achieved, but control is difficult and device becomes complicated
Solution Approach 1:
The patent employs dynamic control through variable rotation speeds of the rotating elements within the foaming chamber. The rotation speed can be adjusted (1000-15000 rpm) to control the degree of aeration and foam density, providing easy operational control without complex mechanical adjustments or temperature regulation systems.
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 produces milk foam with optimal volume, stability, and foaming level by controlling shear stress and expansion, enabling reliable and efficient continuous production.
Implementation Method 1
The basic principle of Couette flow is shown in FIG. 2. In FIG. 2 a movable two-dimensional boundary plate moves with a certain velocity u in respect to a stationary two-dimensional boundary plate. In between the two boundary plates is present a fluid. The movement of the movable boundary plate causes the fluid to move.
Implementation Method 2
Two boundary conditions define the movement of the fluid. Directly at the stationary boundary plate, the fluid does not move at all, due to friction forces at the stationary boundary plate. Therefore, the velocity u is zero. Directly at the movable boundary plate, friction causes the fluid to move with the velocity u of the movable boundary plate.
Data Source
AI summary
The present invention provides a device 1 for producing milk foam, which makes use of Couette flow and a high shear stress that is accordingly applied to a milk-air mixture between two concentrically arranged cylinders 2, 3. The cylinders are rotated relatively to another. The high shear stress leads to an emulsion of the milk and the air, which is the basis for a foaming effect, once the emulsion flows out of a gap 6 between the two cylinders 2, 3 and expands. The parameters of the device 1 that mainly influence the foaming effect are the width of the gap 6 and the relative rotation speed of the cylinders.