Cartridge Mechanical Seal Recess Positioning
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Solution Overview
Problem
The existing cartridge-mechanical seals require complex and costly machining for the seal cover, which is the largest and most expensive part, and have low rigidity due to thin, axially projecting engagement projections, and suffer from reduced versatility due to variations in axial distances between the fixed and rotary rings.
Innovation Solution
The mechanical seal features a first recess on the seal cover and a second recess on the collar, allowing simplified machining and reduced cost production, with a set plate that positions and fixes the seal cover and collar using a projection and recess system, eliminating the need for complex engagement projections and enhancing versatility by accommodating variations in axial distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hook-shaped engagement projections are provided on the seal cover to temporarily fix the collar, then the seal cover and collar can be positioned and fixed, but the seal cover requires time-consuming cutting and complex machining
Solution Approach 1:
The engagement projection is divided into two separate components: a projection on the set plate and a corresponding recess on the seal cover. This segmentation simplifies the seal cover machining while maintaining the positioning function through the distributed recesses.
Solution Approach 2:
Instead of providing engagement projections on the seal cover as in conventional designs, the invention inverts the approach by providing recesses on the seal cover and corresponding projections on the set plate. This inversion simplifies seal cover manufacturing while achieving the same positioning effect.
2Ease of manufacture
If thin axially projecting engagement projections are used on the seal cover, then positioning is achieved, but the rigidity is low leading to breakage during machining
Solution Approach 1:
The engagement structure is segmented into a robust recess on the seal cover and a corresponding projection on the set plate. The recess, being a cavity in the seal cover, provides high rigidity and resistance to machining forces, while the projection on the set plate carries the loading.
Solution Approach 2:
The invention inverts the conventional engagement structure by placing the recess (instead of projection) on the seal cover. This inversion allows the seal cover to have a simple, rigid structure that resists breakage during machining, while the set plate carries the engagement projection that provides the positioning function.
3Manufacturing precision
If the engagement projection dimension is varied to accommodate variations in axial distance between fixed and rotary rings, then positioning accuracy is maintained, but versatility decreases and cost increases
Solution Approach 1:
The seal cover is designed with universal recesses that can accommodate different types of fixed and rotary rings without requiring changes to the seal cover itself. The recesses are positioned and dimensioned to provide accurate positioning regardless of variations in axial distance between the rings, making the seal cover versatile across different applications.
Solution Approach 2:
The set plate acts as an intermediary that adjusts for variations in axial distance between the fixed and rotary rings. By providing adjustment capabilities on the set plate rather than the seal cover, the seal cover maintains its universal design while still achieving accurate positioning for different ring configurations.
Data Source
Figure 1
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AI summary
A cartridge-mechanical seal can be manufactured by easy machining at reduced cost. A first recess 11 is provided on an end face 10a of a seal cover. A second recess 31 is provided on the outer circumference of a collar 30. A set plate 50 is adapted to be fixed to the end face 10a of the seal cover 10. When the set plate 50 is fixed, a projection 51 is inserted in the first recess 11 and in contact with the rotary shaft's 200 side face 11a of the first recess 11, and an end 50a of the set plate 50 is in contact with the bottom 31a of the second recess 31, whereby positioning of the seal cover 10 and the collar 30 with respect to a radial direction is achieved. Moreover, the face of the set plate 50 that faces the seal cover 10 is in contact with the end face 10a of the seal cover 10 and a side face 31b of the second recess 31, whereby positioning of the seal cover 10 and the collar 30 with respect to the axial direction is achieved.