Mechanical Seal with Floating Members and Elastomeric Convolutions
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Solution Overview
Problem
Traditional mechanical seals fail to prevent contaminants from becoming entrenched between moving components, leading to premature failure, especially when using rubber bellows which can create uneven face pressures or detach, allowing contaminants to enter the sealed area.
Innovation Solution
A mechanical seal design featuring an elastomeric member with convolutions, a spring biasing mechanism, and multiple floating members, including a separate seal face component, with a groove on the outer surface to secure the elastomeric member and angled surfaces to enhance fluid flow, preventing detachment and improving sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubber bellows are used to seal between moving components, then contaminants are prevented from entering, but the bellows can become detached allowing contaminants to enter the sealed area
Solution Approach 1:
The elastomeric member is divided into multiple convolutions or bellows sections, each capable of independent movement while maintaining sealing. This segmentation allows the bellows to accommodate axial movement without detaching, as each convolution can expand and contract independently within the confined space between the first and second members.
Solution Approach 2:
The elastomeric member is designed as a flexible bellows structure that can deform axially to accommodate movement between components. The flexible nature of the elastomeric material allows it to maintain sealing contact while expanding and contracting, preventing detachment while blocking contaminants.
2Reliability
If rubber bellows are used to create a seal between moving components, then contaminants are prevented from entering, but uneven face pressures are created
Solution Approach 1:
The elastomeric member is designed with varying convolution densities and wall thicknesses at different locations. The convolutions are more densely packed in regions requiring greater flexibility and less densely packed in regions requiring structural support. This local variation in geometry allows the bellows to maintain more uniform face pressures while still accommodating axial movement.
3Reliability
If a groove is provided on the outer surface of the second member to secure the elastomeric member, then detachment is prevented, but the groove may interfere with fluid flow
Solution Approach 1:
The groove is designed as a shallow circumferential feature rather than a deep radial cavity. By positioning the groove near the outer surface and making it shallow, the seal retention function is maintained while the interference with fluid flow in the central sealing region is minimized. The groove captures the elastomeric member without creating a significant obstacle to fluid passage.
4Adaptability or versatility
If the profile of the elastomeric member comprises convolutions that extend outwardly, then axial movement is allowed, but the overall size of the seal increases
Solution Approach 1:
The convolutions of the elastomeric member are nested within the annular space between the first and second members. The bellows structure folds axially like a nested doll, allowing significant axial compression and extension within a minimal radial envelope. This nesting arrangement enables axial movement capability while keeping the overall seal volume compact and confined to the available annular space.
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 design provides a reliable fluid-tight seal by preventing contaminants from entering the sealed area, reducing the risk of premature failure and enhancing sealing performance through secure engagement and optimized fluid flow around the sealing faces.
Implementation Method 1
The floating component is urged towards the static component to close the seal faces together to form a sliding face seal, usually by means of one or more spring members.
Implementation Method 2
the profile of the elastomeric member comprising one or more convolutions which extend outwardly to allow the floating members to move in an axial direction
Data Source
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AI summary
A mechanical seal comprising an elastomeric member, a spring biasing means, a longitudinally floating first member comprising a seal face, a longitudinally non-floating second member and a longitudinally floating third member. The elastomeric member is in sealing engagement with the first member, second member and third members and the spring biasing means are longitudinally positioned between the first member and the second member. One of the first member and the second member is provided with at least one protruding male portion and the other of the first member and the second member is provided with corresponding female portion into which the male portion locates.