Sanitary Fitting Seal Geometry to Prevent Binding and Rippling
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Solution Overview
Problem
Conventional seals in pharmaceutical, dairy, and beverage industries face issues such as 'binding', 'rippling up', and 'intrusion' during cleaning, leading to loss of sealing effect and hygienic concerns, especially for agitator couplings with exposed O-rings that can fall out.
Innovation Solution
A hygienic coupling and fitting seal system featuring a tail with annular surfaces and peripheral edges, including annular rings that form a seal with a smooth exterior profile, preventing protrusions and ensuring reliable sealing while being easy to clean, using compression-controlled and self-lubricating materials like TEFLON-based thermoplastics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seals (flat gaskets, O-rings) are used in sanitary applications, then sealing effect is provided, but binding, rippling up, and intrusion occur during cleaning causing loss of sealing effect and hygienic issues
Solution Approach 1:
The seal is designed with a continuously curved exterior surface that transitions smoothly from the first peripheral edge to the second peripheral edge, eliminating any protrusions or sharp edges. This curved geometry prevents binding and rippling during cleaning operations while maintaining effective sealing contact between the seal and the mating surfaces.
Solution Approach 2:
The seal incorporates different functional zones: the exterior surface is optimized for cleanability with continuous curvature, while the interior maintains the necessary sealing geometry with annular rings and tail structure. This local differentiation allows the seal to simultaneously achieve hygienic cleanability and reliable sealing performance.
2Reliability
If exposed O-rings are used for agitator couplings, then sealing is provided, but the O-rings can fall out during operation
Solution Approach 1:
The seal is nested within a recess or groove structure formed by the tail and annular rings, which retains the seal in position during operation. The tail extends into a corresponding recess in the coupling, preventing the seal from falling out while maintaining the sealing effect between the nested components.
3Reliability
If seals with protrusions are used, then sealing contact is improved, but cleanability is reduced creating hygienic issues
Solution Approach 1:
The exterior surface of the seal is designed with continuous curvature and no protrusions, allowing cleaning fluids to flow smoothly over the surface without trapping contaminants in crevices or sharp edges. This curved geometry maintains sealing contact while enabling effective cleaning for hygienic applications.
4Reliability
If compression force is applied to conventional seals, then sealing effect is improved, but shape change and extrusion occur leading to binding and rippling
Solution Approach 1:
The seal is made from compression-controlled and self-lubricating materials that change their physical properties under compression. The material exhibits controlled compressibility that allows it to conform to mating surfaces for effective sealing while resisting excessive shape change and extrusion that would cause binding and rippling during cleaning.
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 seal system maintains a consistent sealing effect, prevents extrusion, and ensures easy cleanability by limiting shape change under compression, reducing the risk of binding and rippling, thus addressing hygienic and operational issues in sanitary applications.
Implementation Method 1
compression-controlled and self-lubricating materials like TEFLON-based thermoplastics
Implementation Method 2
compression-controlled and self-lubricating materials like TEFLON-based thermoplastics
Data Source
AI summary
In one example, a hygienic fitting assembly is disclosed. The hygienic fitting assembly includes a first fitting member defining an exterior opening, an interior opening, and a passage extending therebetween. The hygienic fitting assembly further includes a second fitting member receivable by the first fitting member with the first and second fitting members configured for removable mechanical attachment with one another along an interface region within the passage. The hygienic fitting assembly further includes a seal formed from a compression controlled and self-lubricating material. The seal is configured to receive an annular feature of one of the first or second fitting members and define sanitary fitting connection therebetween. The sanitary fitting connection is operable to prevent fluid escape toward the interface region during flow of a product between the first and second fitting members.