Mechanical Seal Rotational Coupling Design
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Solution Overview
Problem
Existing mechanical seal designs with pressed components suffer from torsional misalignment, rotational twisting, and sharp edges, leading to ineffective drive mechanisms, assembly errors, and damage to sealing members, which increase costs and reduce performance.
Innovation Solution
A mechanical seal design featuring an elastomeric member, spring biasing, and longitudinally restrained members with radially protruding portions for rotational coupling, eliminating the need for subsequent machining and minimizing components for reduced assembly time and cost, while enhancing the drive surface area beyond material thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pressed components are used to reduce manufacturing cost, then manufacturing cost is reduced, but the drive mechanism becomes ineffective due to torsional misalignment and rotational twisting
Solution Approach 1:
The drive mechanism is segmented into distinct functional elements: a drive member with drive surfaces, a driven member with complementary drive surfaces, and a resilient member. This segmentation allows each component to be optimized for its specific function while maintaining overall reliability through modular assembly.
Solution Approach 2:
The drive mechanism combines pressed metal components with a resilient member (such as a rubber or elastomeric element). This composite approach allows the rigid pressed parts to provide structural integrity and cost-effectiveness, while the resilient member compensates for misalignment and prevents rotational twisting, thereby maintaining drive effectiveness.
2Ease of manufacture
If pressed components are used to eliminate subsequent machining operations, then manufacturing cost is reduced, but sharp edges and corners damage sealing members and operators
Solution Approach 1:
The resilient member is positioned between the pressed components and the sealing members to provide beforehand cushioning. This resilient element absorbs the impact of sharp edges and corners from the pressed components, preventing damage to the sealing members during assembly and operation.
Solution Approach 2:
The resilient member acts as an intermediary element between the pressed metal components and the sealing members. It mediates the interaction by providing a compliant interface that protects the sealing members from direct contact with sharp edges while still allowing effective force transmission.
3Length of moving object
If open ended longitudinal castellations are used for drive mechanism, then component thickness can be reduced, but installation errors occur due to disengagement and longitudinal forces stretch sealing members
Solution Approach 1:
The harmful open ended castellations are extracted from the design and replaced with enclosed drive surfaces. The drive mechanism uses continuous drive surfaces on the drive and driven members that are engaged by the resilient member, eliminating the disengagement problems associated with open ended castellations while maintaining thin component thickness.
4Adaptability or versatility
If multiple separate components are used for mechanical seal, then functionality can be optimized, but assembly time and complexity increase
Solution Approach 1:
The drive mechanism merges the drive member, driven member, and resilient member into a compact integrated assembly. The resilient member connects the drive and driven members in a way that combines their functions while reducing the overall assembly complexity and minimizing the number of separate components that need to be handled during installation.
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 improved rotational coupling, reduced assembly errors, and enhanced sealing performance by preventing misalignment and damage, thus offering a cost-effective and efficient mechanical seal assembly.
Implementation Method 1
The seal face assembly is spring biased towards the stationary seal face by a longitudinal spring force applied to the seal face assembly by a spring member.
Implementation Method 2
The rotary seal face is sealed to the shaft by an elastomeric member radially compressing the seal face to the shaft.
Data Source
AI summary
A mechanical seal includes an elastomeric member, a spring biasing device, a longitudinally floating first member, a longitudinally non-floating second member and a longitudinally floating seal face. The elastomeric member is in a sealing engagement with the seal face. The first and second members and the spring biasing device are longitudinally positioned between the seal face and the second member. The first member and the second member are longitudinally restrained and rotationally coupled by at least one substantially male radially protruding portion in one of the members engaging in at least one substantially female portion in the other member of the two members. The first and second members are arranged for a sealing engagement with the seal face in a single seal utilizing the elastomeric member, or with the seal face and an additional seal face in a double seal utilizing an additional elastomeric member.