Shaft Seal Holding Ring for Hygienic Clamp Attachment
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Solution Overview
Problem
Existing mechanical sealing devices for pumps that transport foodstuffs and medicines require modifications to the shaft surface for attachment, which complicates cleaning and hygiene due to the presence of recesses and unevennesses.
Innovation Solution
A holding device with an annular body featuring an inclined inner surface and clamping elements designed as segments of a ring, allowing for secure attachment without surface modifications, distributing pressure forces evenly to prevent stress concentrations and deformations, and utilizing screw elements and spring elements for reliable clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing element is attached on a shaft by means of an annular body with a radially inwardly projecting portion received in a recess in the shaft surface, then a reliable attachment is obtained, but the shaft surface requires cutting and recess formation which complicates cleaning and hygiene
Solution Approach 1:
The invention extracts the clamping function from the shaft surface itself and relocates it to a separate clamping element. The clamping element with its inclined inner surface and radially inwardly projecting portion provides the attachment mechanism independently, eliminating the need for recesses or cuttings in the shaft surface. This separates the attachment function from the shaft structure, maintaining reliability while preserving surface integrity for hygiene purposes.
Solution Approach 2:
The clamping element acts as an intermediary between the shaft and the sealing element. Instead of directly modifying the shaft surface for attachment, the clamping element mediates the connection by clamping onto the shaft's outer surface and securing the sealing element. This intermediary component enables reliable attachment without compromising the shaft surface.
2Reliability
If pressure force is concentrated on a small area of the shaft surface, then secure clamping is achieved, but stress concentrations and deformations occur
Solution Approach 1:
The clamping element is designed as a segment of a ring rather than a complete ring, allowing optimization of the contact geometry. The inclined inner surface of the clamping element segment distributes the clamping force over a larger axial area of the shaft, reducing stress concentration while maintaining secure attachment. This segmentation approach enables force distribution without requiring a complete circular structure.
Solution Approach 2:
The clamping element features an inclined inner surface that creates a curved contact geometry with the shaft. This curved surface distributes the radial clamping force over a larger area compared to a flat surface, reducing stress concentrations on the shaft while maintaining effective clamping pressure for secure attachment.
3Ease of operation
If a clamping element with inclined inner surface is used, then a relatively small displacement force is required, but the clamping element design becomes more complex
Solution Approach 1:
The inclined inner surface of the clamping element creates a wedge-like geometry that converts axial displacement force into radial clamping force. This inclined curved surface provides mechanical advantage, reducing the axial force required for displacement while generating sufficient radial clamping pressure. The curvature is optimized to balance force reduction with geometric simplicity.
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
Enables a simple, reliable, and hygienic attachment of sealing elements on shafts, maintaining a smooth surface for easy cleaning and ensuring effective sealing without stress concentrations, suitable for high-hygiene industries like food and pharmaceuticals.
Implementation Method 1
the screw element comprises a threaded portion to be engaged with a threaded portion of the clamping element and a head portion which is rotatably arranged in the annular body
Implementation Method 2
the holding device comprises a spring element which acts with a force in an axial direction on the clamping element
Data Source
Figure 1
Figure 2~3
AI summary
The claimed invention concerns a holding device for application of a sealing member (21) on a shaft (23). The holding device (22) includes a connecting mechanism (26, 27) adapted to connect the sealing member (21) on the shaft (23). The connecting mechanism includes an annular body (24) that comprises an inner surface (24a) which, in an axial direction, is arranged at gradually decreasing radial distance from the shaft (23). The connecting mechanism comprises at least a clamping element (26) arranged in a space between the inner surface (24a) of the annular body and the shaft (23), and a displacement mechanism (27) adapted to displace the clamping member in said axial direction relative to the annular body (24) to a position in which the inner surface (24a) of the annular body presses the clamping element to the shaft. The claimed invention also relates to a mechanical sealing device including such a holding device and a hydrodynamic machine having such a mechanical sealing device for applying a sealing member on a shaft.