Elastomer-Coated Spring Shaft Seal for Medical Sterilization
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Solution Overview
Problem
Existing shaft seals are not easily cleanable and fail to provide reliable sealing, especially in medical applications where they must withstand chemical and thermal stresses during sterilization, and have issues with mechanical properties and tolerance adjustments.
Innovation Solution
A shaft seal with a U-shaped or V-shaped annular spring coated with elastomer, where the spring's limbs are supported on the flange area and sealing lip, allowing for reliable sealing and easy cleaning, and the elastomer coating maintains mechanical properties while enhancing cleanability and sealing under pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the spring is embedded in the seal material (potting with silicone), then the seal structure is simplified, but the mechanical properties of the spring are altered and the seal becomes very stiff
Solution Approach 1:
The invention separates the spring from the elastomer body, making the spring a distinct, removable component rather than embedding it in the material. This segmentation preserves the spring's mechanical properties while simplifying the overall seal structure and enabling easy replacement and cleaning.
2Reliability
If the sealing lip and spring are protected by a low-friction plastic ring, then the radial force is maintained in aggressive media, but the cleanability is reduced
Solution Approach 1:
The invention uses homogeneous elastomer material for both the sealing lip and the protective coating on the spring, eliminating the need for separate low-friction plastic rings. This provides the sealing stability of elastomer while maintaining cleanability, as the elastomer surface can be easily cleaned and sterilized.
3Reliability
If the shaft seal is designed for reliable sealing with tolerance compensation, then the sealing performance is improved, but the cleanability and sterilization resistance are compromised
Solution Approach 1:
The invention employs a dynamic spring mechanism that can be easily removed and replaced, allowing the seal to adapt to different shaft tolerances while maintaining cleanability. The spring provides continuous contact pressure compensation for tolerance variations, and its removable nature enables easy cleaning and sterilization without compromising sealing performance.
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 solution provides a reliable, easy-to-clean shaft seal that maintains sealing integrity under varying pressures and temperatures, ensuring safety and longevity in medical applications by compensating for tolerances and resisting contamination and steam ingress during sterilization.
Implementation Method 1
The coating with the elastomer material is sufficiently thin, or the elastomer material is sufficiently flexible, to ensure that the mechanical properties of the spring are not appreciably altered
Implementation Method 2
a radially inner sealing lip, i.e. a sealing lip arranged to the inside of the flange area
Implementation Method 3
A substantially annular spring is arranged on a radially outer face of the sealing lip and presses the sealing lip or the sealing edge onto the surface of the shaft
Data Source
AI summary
A shaft seal includes a radially outward flange area and a radially inward sealing lip connected to the flange area. An annular spring with a U-shaped or V-shaped cross section is arranged on a radial outer face of the sealing lip, wherein an outer limb bears on the flange area and an inner limb bears on the sealing lip, and wherein a surface of the spring exposed to an exterior of the shaft seal is coated with an elastomer. The invention also relates to a method for producing a shaft seal.