Beverage preparation device with disk valve and operating method
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Solution Overview
Problem
Ceramic disk valves in beverage preparation devices, such as coffee machines, face sealing issues due to constant contact pressure that decreases over the device's lifespan, leading to unreliable sealing performance.
Innovation Solution
A pressure chamber is formed outside the fluid opening, using an elastomer seal to exert hydraulic pressure on the cover disk, ensuring a dynamic sealing force that adapts to operating conditions by varying fluid pressure, with the pressure chamber's cross-sectional area being significantly larger than the fluid opening to maintain adequate sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant contact pressure is applied by spring to ensure sealing, then sealing force is initially sufficient, but sealing reliability deteriorates over service life due to decreasing spring forces
Solution Approach 1:
The patent transforms the static spring pressure system into a dynamic hydraulic pressure system. The contact pressure on the cover disk is no longer constant but varies dynamically with fluid pressure in the pressure chamber. This allows the sealing force to automatically adapt to operating conditions and maintain effectiveness throughout the device's service life without degradation from spring fatigue.
Solution Approach 2:
The patent introduces a pressure chamber filled with fluid (water or steam) that communicates with the fluid flow paths. The hydraulic pressure of this fluid acts on the cover disk to generate contact pressure, replacing the mechanical spring system. This hydraulic approach provides sustained pressure capability and automatic adaptation to system pressure variations.
2Reliability
If pressure chamber cross-sectional area is increased to at least 20% of cover disk area to ensure adequate sealing force, then sealing effectiveness is improved, but device complexity increases
Solution Approach 1:
The pressure chamber serves multiple functions simultaneously: it acts as a sealing pressure source, a fluid distribution chamber, and an integral part of the valve body structure. By making the pressure chamber an inherent feature of the valve housing rather than a separate component, the design achieves adequate sealing force without proportionally increasing overall device complexity.
Solution Approach 2:
The patent merges the pressure chamber with the valve housing structure, eliminating the need for separate pressure containment components. The elastomer seal integrates the pressure chamber boundary with the sealing function, combining structural support and sealing roles into a unified design that minimizes additional complexity.
3Reliability
If elastomer seal is used to delimit pressure chamber and support on cover disk, then dynamic sealing force is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The elastomer seal provides flexible, compliant sealing that can accommodate minor variations in manufacturing tolerances and assembly conditions. The elastic material deforms to maintain sealing contact, compensating for small dimensional deviations without requiring extremely tight manufacturing precision, while still achieving reliable dynamic sealing.
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 solution ensures reliable sealing over the device's lifespan by automatically adjusting contact pressure based on fluid pressure, maintaining a strong sealing force even as the device ages, thus preventing leakage and ensuring consistent performance.
Implementation Method 1
a pressure chamber is formed outside the fluid opening, within which, by means of the fluid flowing through it, in particular in all switching circuits of the disk valve, a contact pressure can be exerted along the axis of rotation on the outer end face of the cover disk
Implementation Method 2
an elastomer seal, preferably designed as a circumferentially closed directional seal, which is supported in the axial direction on the cover disk
Data Source
Figure 1
AI summary
The invention relates to a beverage preparation device (1) with a disk valve (6), comprising a valve housing (12) and a stack of disks (7) arranged therein, the disk valve having a preferably ceramic cover disk (8) comprising at least one fluid opening for fluid (5), especially water and/or steam, preferably embodied as a fluid inlet, and at least one control disk (10) arranged on a side of the cover disk (8) facing away from an outer front side of the cover disk (8), the control disk (10) being rotatable, manually and/or by means of a drive, about a rotational axis (R) in relation to the cover disk (8), between different operating positions. A pressure chamber (15) is formed outside the fluid opening (11), inside which a bearing pressure (P) can be exerted, by means of the fluid (5) flowing therethrough, along the rotational axis (R) on the outer front side (14) of the cover disk (9) in the direction of the control disk (10), and the pressure chamber (15) is delimited, in the radial direction in relation to the rotational axis (R), by an elastomer seal (13) preferably embodied as a peripherally closed ring seal, said seal being supported on the cover disk (8) in the axial direction. A cross-sectional surface of the pressure chamber, surrounded by the elastomer seal (13), and/or the pressure surface section (17) of the outer cover disk (8) adjacent to the fluid opening (11), which can be subjected to hydraulic pressure, corresponds to at least 20% of the axial projection surface of the cover disk (8) and/or the cross-sectional surface of the pressure chamber and/or the pressure surface section (17) of the outer cover disk (8) adjacent to the fluid opening (11), which can be subjected to hydraulic pressure, is larger than a cross-sectional surface of the fluid opening (11).