Milk Foam Device Using Couette Flow Shear for Continuous Foaming
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Solution Overview
Problem
Existing devices for producing milk foam are limited by batch processes, inability to be integrated in-line with fluid flow paths, and unreliable foaming due to difficult control of influencing factors such as geometry and steam temperature.
Innovation Solution
A device utilizing Couette flow to apply high shear energy to a milk-air mixture within a gap between rotating cylinders, allowing for continuous foaming and precise control of foaming parameters like gap width, rotation speed, and exposure time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch process foaming devices are used, then foaming can be achieved with simple structure, but productivity is limited and continuous operation is not possible
Solution Approach 1:
The patent implements continuous foaming operation by replacing the batch process with a continuous flow system. Milk flows continuously through the device while the rotor-stator system operates continuously to generate foam, eliminating the need to empty and refill the reservoir between batches. This allows the device to produce foam continuously as long as milk is supplied.
2Adaptability or versatility
If steam injection is used for foaming, then foaming effect can be achieved, but the device cannot be integrated in-line with fluid flow paths
Solution Approach 1:
The patent replaces the thermal field approach (steam injection) with a mechanical field approach (rotor-stator shear mixing). The mechanical rotation of the rotor within the stator creates intense shear forces that mechanically incorporate air into the milk, producing foam without requiring steam injection. This mechanical method is more suitable for in-line integration.
3Reliability
If simple foaming devices are used, then device complexity is low, but foaming reliability is poor due to difficult control of influencing factors
Solution Approach 1:
The patent achieves reliable and consistent foaming by precisely controlling key parameters of the rotor-stator system. The gap width between rotor and stator, rotation speed, and milk flow rate are all controllable parameters that directly influence foam quality. By maintaining consistent parameter values during operation, the device produces reliable foam with consistent properties.
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
Enables reliable and continuous production of milk foam with optimal properties, such as volume and stability, by easily controllable parameters, and can be integrated into beverage production systems.
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
A device for producing milk foam uses Couette flow and a high shear stress that is accordingly applied to a milk-air mixture between two concentrically arranged cylinders. 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 between the two cylinders and expands. The parameters of the device that mainly influence the foaming effect are the width of the gap and the relative rotation speed of the cylinders.