Tank Nozzle Seal Structure Without a Combifit Ring
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Solution Overview
Problem
Conventional tank seals for radar level gauges, such as those using the Combifit ®< ring, face challenges in achieving precise metal-to-metal axial and radial positioning and adequate sealing while adhering to health regulations like EHEDG, particularly due to complex tolerance requirements and the need for a metal ring with curved interfaces.
Innovation Solution
A redesigned attachment collar for radar level gauges featuring an annular abutment surface and a surrounding ridge ensures radial alignment and precise axial positioning without a Combifit ®< ring, utilizing a sealing gasket sandwiched between the sealing surface and the tri-clamp flange, allowing for improved tolerance and cost-efficient mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Combifit ® ring is used for tank sealing, then sealing performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the Combifit ® ring from the sealing system entirely. Instead of using a separate Combifit ® ring component, the sealing is achieved through a groove in the tank nozzle that directly receives and retains the sealing gasket, eliminating the need for the complex Combifit ® ring structure while maintaining sealing effectiveness.
Solution Approach 2:
The tank nozzle groove serves multiple functions: it provides the sealing surface for the gasket, acts as a retention mechanism through its geometry, and eliminates the need for separate positioning components. This multi-functional design replaces the specialized Combifit ® ring with a simpler integrated solution.
2Reliability
If a Combifit ® ring is used for tank sealing, then sealing performance is improved, but manufacturing cost increases
Solution Approach 1:
By removing the Combifit ® ring component, the patent eliminates its associated manufacturing cost. The sealing gasket alone, retained by the groove, provides sufficient sealing performance without requiring the expensive Combifit ® ring assembly.
Solution Approach 2:
The patent uses a simple, inexpensive sealing gasket instead of the more expensive Combifit ® ring. The groove design provides adequate retention for the gasket without requiring durable, complex retention mechanisms, achieving cost-effective sealing.
3Reliability
If metal-to-metal axial and radial positioning is required for EHEDG approval, then hygiene compliance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The groove design uses asymmetric geometry with a bottom surface for axial positioning and side surfaces for radial positioning. This asymmetric groove configuration provides the necessary metal-to-metal contact for EHEDG compliance while accommodating normal manufacturing tolerances without requiring ultra-precise positioning.
Solution Approach 2:
The groove provides localized metal-to-metal contact surfaces at specific positions (bottom for axial, sides for radial) that satisfy EHEDG hygiene compliance requirements. Only these local contact areas require high precision, while the overall assembly can tolerate normal manufacturing variations.
4Ease of operation
If a conventional tri-clamp connection with symmetric flanges is used, then ease of assembly is improved, but adaptability to gauging instruments decreases
Solution Approach 1:
The patent separates the sealing function from the clamping function. The groove in the tank nozzle handles sealing and positioning, while the tri-clamp flange handles clamping. This segmentation allows the gauging instrument attachment to use a simple flange design without needing to conform to conventional symmetric double-flange configurations, improving adaptability.
Solution Approach 2:
The groove acts as an intermediary element between the tank nozzle and the sealing gasket, providing a standardized interface that simplifies instrument mounting. This intermediary structure enables versatile attachment of different gauging instruments while maintaining ease of assembly through the familiar tri-clamp mechanism.
Data Source
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AI summary
A gauging instrument adapted for mounting on a nozzle of a tank, the instrument comprising an attachment collar configured to be aligned with the nozzle and to be secured by means of an annular clamping device. The attachment collar includes an annular sealing surface, an annular abutment surface located radially outside the sealing surface, and a ridge located radially outside the abutment surface. The gauging instrument further comprises a sealing gasket fitted radially inside the abutment surface. When the gauging instrument is mounted on a tri-clamp flange of the tank nozzle, the ridge ensures radial alignment, the annular abutment surface ensures a precisely defined axial relation, and the sealing gasket is sandwiched between the sealing surface and the tri-clamp flange. With his design, alignment and sealing are accomplished without the need of a Combifit® ring, leading to a more cost-efficient mounting.