Shaft Seal Clamping Ring for Hygienic Attachment Without Recesses
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Solution Overview
Problem
Existing mechanical sealing devices for pumps used in the food and pharmaceutical industries face challenges in attaching sealing elements to shafts without creating uneven surfaces that can harbor contaminants, as traditional attachment methods require cutting or recesses on the shaft, which are difficult to clean and maintain hygienic standards.
Innovation Solution
A holding device with an annular body featuring an inclined inner surface and a clamping element designed as a segment of a ring, allowing for secure attachment without modifying the shaft surface, distributing pressure forces evenly to prevent stress concentrations and deformations, and incorporating multiple clamping elements and a screw mechanism for reliable attachment.
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 or recesses which create unevennesses where contaminants can get stuck
Solution Approach 1:
A clamping element is introduced as an intermediary component between the annular body and the shaft. The clamping element has an inner surface that contacts the shaft and an outer surface with a corresponding shape to the inner surface of the annular body, distributing pressure forces evenly and eliminating the need for recesses in the shaft surface while maintaining reliable attachment
Solution Approach 2:
The invention changes the attachment mechanism from mechanical interlocking (requiring recesses) to friction-based clamping. By applying axial force through the displacement mechanism, the clamping element generates sufficient friction force against the shaft surface to maintain reliable attachment without creating unevennesses
2Object-affected harmful factors
If a clamping element is used to attach the sealing element without cutting the shaft surface, then a smooth and clean surface is maintained, but sufficient clamping force must be applied to prevent loosening during rotation
Solution Approach 1:
The clamping element is designed with a curved inner surface that corresponds to the curvature of the shaft, and the annular body has an inclined inner surface. This curved geometry distributes the clamping force evenly around the shaft circumference, preventing stress concentrations and maintaining surface smoothness while providing sufficient total clamping force
Solution Approach 2:
The clamping element is designed as a segment of a ring rather than a complete ring, allowing it to be positioned and adjusted optimally on the shaft. This segmentation enables precise positioning and even distribution of clamping force across the contact area
3Reliability
If multiple clamping elements are arranged at constant intervals around the shaft, then pressure forces are distributed optimally and attachment reliability is improved, but device complexity increases
Solution Approach 1:
While the invention can accommodate multiple clamping elements arranged symmetrically at constant intervals for optimal pressure distribution, the design allows for asymmetric arrangement as well. This flexibility enables adaptation to different shaft sizes and application requirements without strictly increasing complexity, as the same basic clamping element design can be used in different quantities and positions
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 enables a simple, reliable, and hygienic attachment of sealing elements to shafts, ensuring a smooth, leak-proof rotation while maintaining a clean and even surface, suitable for high-hygiene applications like food and pharmaceutical processing.
Implementation Method 1
The pressure force transmitted from the clamping element to the shaft may thus be distributed over the entire contact area which reduces the risk for stress concentrations and deformations of said surfaces
Data Source
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.