Dual-Gasket Brewing Piston for Coffee Machine Leak Control
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Solution Overview
Problem
Super-automatic coffee machines experience leaks due to degradation of sealing elements under thermal and mechanical stress, leading to frequent replacements and ineffective prevention of liquid and coffee powder passage through the piston gaskets.
Innovation Solution
A brewing piston and cylinder design featuring two gaskets and two conduits, where the second conduit injects liquid between the gaskets to reduce pressure differences and prevent leaks, with the second gasket being positioned outside the cylinder during resting to avoid thermal stress, and the first gasket being designed to handle ground coffee effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single gasket is used in the brewing piston, then the device complexity is reduced, but the reliability of sealing deteriorates due to degradation under thermal and mechanical stress
Solution Approach 1:
The brewing piston is divided into two separate gaskets (first gasket and second gasket) positioned at different locations. The first gasket is located at the lower end of the piston head, while the second gasket is positioned at the upper end. This segmentation allows each gasket to handle different sealing requirements, with the first gasket dealing with coffee powder and the second gasket handling liquid sealing, thereby improving overall sealing reliability without requiring a single complex sealing structure
Solution Approach 2:
A second conduit is introduced as an intermediary element that injects liquid between the first and second gaskets. This liquid injection serves as a mediator that lubricates the gasket interfaces, reduces friction and thermal stress, and prevents direct contact between the gaskets and the hot coffee infusion, thereby protecting the gaskets from degradation while maintaining sealing effectiveness
2Reliability
If the second gasket remains inside the cylinder during resting position, then the sealing continuity is maintained, but the thermal stress on the gasket increases leading to faster degradation
Solution Approach 1:
The second gasket is designed to be dynamically positioned - it moves between being inside the cylinder during brewing operations and outside the cylinder during resting positions. This dynamic positioning allows the gasket to be exposed to thermal stress only when necessary for sealing during brewing, while being removed from the hot environment during resting periods to allow cooling and reduce cumulative thermal degradation
Solution Approach 2:
The second gasket undergoes periodic movement between inside and outside positions of the cylinder, corresponding to the brewing cycle. During the brewing phase, the gasket is positioned inside to maintain sealing continuity. During the resting phase, the gasket moves outside to reduce thermal exposure. This periodic action balances the need for continuous sealing during operation with the need to minimize thermal stress accumulation over time
3Productivity
If high pressure is applied in the infusion chamber for brewing, then the coffee extraction efficiency is improved, but the pressure causes coffee powder to adhere to the cylinder wall and degrade the sealing element
Solution Approach 1:
The second conduit introduces liquid as an intermediary substance between the high-pressure coffee infusion and the gaskets. This injected liquid creates a protective layer that prevents the abrasive coffee powder mixture from directly contacting and degrading the sealing elements, while still allowing the high pressure needed for effective coffee extraction to be maintained in the brewing chamber
Solution Approach 2:
The high pressure that initially causes harmful abrasive effects is converted into a beneficial force by redirecting it through the second conduit to inject liquid between the gaskets. The same pressure that could degrade the sealing elements is now used to force lubricating liquid onto the gasket surfaces, transforming the harmful high-pressure contact into a protective high-pressure lubrication system
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 design significantly extends the lifespan of sealing elements by reducing pressure on the gaskets, minimizing leaks, and maintaining the gaskets' integrity through reduced thermal exposure and effective lubrication, ensuring the coffee machine operates efficiently with reduced contamination risks.
Implementation Method 1
at least one second conduit for injecting the liquid between the first gasket and the second gasket during infusion preparation
Implementation Method 2
The injection of water into the space 25c between the gaskets 31 and 32, respectively, provides the following effects: the second gasket 32 protects against water leaks... the water injected through the second hole 85b acts as a lubricant or glide and cleans the brewing cylinder 21
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
The present invention relates to a brewing piston (23) for infusion preparation, comprising a head (25) associated with a filtering element (25a), and a lateral surface (25b) having at least one first gasket (31) located in proximity of the head (25) and at least one second gasket (32) located at a predetermined distance from the at least one first gasket. The brewing piston further comprises at least one first conduit (81a) connected to the head (25) and arranged to inject a liquid for infusion preparation, and at least one second conduit (81b) connected to the lateral surface (25b) between the gaskets (31, 32) and arranged to inject the liquid between the at least one first gasket (31) and the at least one second gasket (32) during infusion preparation. The piston as disclosed is arranged to limit or avoid leaks in a machine for infusion preparation. The invention also relates to a machine using the piston according to the invention and to a method of limiting or avoiding leaks in a machine for infusion preparation.