Ceramic Disc Valve Spring Loading for Stable Sealing Pressure
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Solution Overview
Problem
Ceramic disc valves in hot beverage preparation devices, such as espresso machines, face significant wear due to exposure to boiling water and steam, leading to limescale deposits and reduced service life, as existing seals are burdened with both sealing and contact pressure responsibilities, resulting in inconsistent performance over time.
Innovation Solution
The introduction of spring elements, specifically designed to maintain a constant contact pressure between valve discs, separates the sealing and contact pressure functions, using materials like metal for resistance to thermal influences and flat spring characteristics to ensure quasi-constant pressure resistance, while a seal carrier supports the spring elements and seals, allowing for reliable sealing and pressure relief mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If seals are designed to provide both sealing and contact pressure, then the valve can be constructed with fewer components, but the service life is reduced due to plastic deformation of rubber seals caused by aging
Solution Approach 1:
The invention separates the dual function of seals into two distinct components: seals for sealing and spring elements for contact pressure. This segmentation allows each component to be optimized for its specific function, preventing plastic deformation of seals and extending service life.
Solution Approach 2:
Spring elements act as an intermediary component between the housing and valve disks, providing the necessary contact pressure without requiring the seals to perform this function. This intermediary element protects the seals from excessive stress and aging.
2Reliability
If contact pressure is set higher as a precaution when the disk valve is new, then sealing reliability is improved initially, but lubricant is squeezed out between the valve disks making the valve disks difficult to move
Solution Approach 1:
The spring elements provide a dynamic contact pressure that maintains sealing reliability without excessively high initial pressure. The spring characteristic is designed to be as flat as possible, providing consistent pressure that prevents lubricant squeeze-out while ensuring proper sealing.
3Device complexity
If rubber seals are used for both sealing and contact pressure, then the valve construction is simpler, but the contact pressure becomes inconsistent over time due to compression set
Solution Approach 1:
The invention uses metal spring elements with a flat spring characteristic that maintain consistent contact pressure over time. These spring elements replace the need for rubber seals to provide contact pressure, as metal springs do not suffer from compression set and aging issues.
4Temperature
If spring elements made of metal are used, then resistance to thermal influences is improved, but the device complexity increases
Solution Approach 1:
The invention changes the material parameter of the contact pressure element from rubber to metal, specifically selecting metal spring elements with a flat spring characteristic. This parameter change provides resistance to thermal influences while maintaining consistent contact pressure over the service life.
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
This design enhances the service life of ceramic disc valves by maintaining consistent contact pressure and preventing premature seal degradation, reducing the risk of lubricant loss and ensuring reliable operation over the valve's lifespan, with the added benefit of potentially eliminating the need for a separate pressure relief valve.
Implementation Method 1
spring elements for applying a defined contact pressure between the housing and the valve disks... they have a spring characteristic that is as flat as possible, at least flatter than that of rubber. As a result, they provide a largely constant contact pressure even if the seals deteriorate due to aging.
Data Source
AI summary
A ceramic disc valve for hot beverage preparation devices for household purposes, in particular for fully automatic coffee machines, with a pressure supply line, with at least one pressure outlet (16; 18) and with a housing (10, 12) as a holding device for ceramic valve discs (20; 22; 24) arranged therein, which are closely adjacent to each other and adjustable relative to each other, namely at least one fixed distributor disc (20; 24) and at least one adjustable control disc (22), and with a seal (28; 30) in each case for sealing the valve discs (20; 22; 24) against the housing (10, 12), is further developed by spring elements (46) for applying a contact pressure between the housing (10, 12) and the valve discs (20; 22; 24).