Double-Seat Valve Diaphragm Layout for Leakage Space Drainage
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Solution Overview
Problem
Double-seat valves used as tank-bottom valves face challenges in emptying the leakage space without pressure build-up, especially when the design requires a large flow cross-section for the hollow rod, which can lead to excessive pressure during cleaning and reduced hygiene due to potential backflow.
Innovation Solution
The double-seat valve incorporates a diaphragm with a leakage channel that connects the leakage space to a housing part, allowing drainage through the hollow rod, and features choke gaps to manage pressure and enhance cleaning efficiency, along with a guiding means to center the valve disks and reduce mechanical stress on the diaphragm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hollow rod is designed with large flow cross sections to enable emptying of the leakage space while preventing backflow, then the cleanability and hygiene are improved, but the outer diameter of the hollow rod increases
Solution Approach 1:
The hollow rod is segmented into multiple sections with different functions: an upper section with a large flow cross-section for draining the leakage space, and a lower section with a smaller diameter for passing through the diaphragm seal. This segmentation allows the rod to provide both large drainage capacity and maintain a compact size at the critical diaphragm penetration point.
Solution Approach 2:
The hollow rod transitions from a uniform cylindrical shape to a stepped configuration with varying diameters along its length. This dimensional change allows the rod to optimize flow cross-section in different axial positions, achieving both large drainage area and small penetration diameter through the diaphragm.
2Stress or pressure
If the leakage channel in the hollow rod has a large channel cross section to prevent pressure build-up, then the pressure compensation is improved, but the hollow rod requires larger dimensions
Solution Approach 1:
The hollow rod's leakage channel is segmented into different sections with optimized cross-sections. The upper portion has a larger channel cross-section to effectively drain the leakage space and prevent pressure build-up, while the lower portion maintains smaller dimensions for compact installation through the diaphragm.
Solution Approach 2:
Different sections of the hollow rod are designed with different local qualities - the upper section has larger flow cross-sections for pressure relief, while the lower section has smaller dimensions. This local differentiation allows the rod to provide pressure compensation where needed without requiring large dimensions throughout its entire length.
Data Source
AI summary
A double-seat valve includes a housing having a passage between first and second connections. First and second valve disks are arranged in a housing internal space. A leakage space formed in the passage in the valve closed position is sealed off by the second valve disk. A hollow rod connected to the first valve disk has a leakage channel connecting the leakage space and a housing part. A cleaning gap is formed between the second valve disk and a passage wall. A housing opening is sealed with a diaphragm that separates the housing part from the internal space. A section of the first valve disk is received in an opening contour in the passage in the valve closed position, and delimits a cut-out in the first valve disk, in which the second valve disk is received in the valve open position.