Mechanical Seal Stop Ring Eliminates Spacer Wear

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Solution Overview

Problem

Traditional mechanical seals for rotodynamic pumps require extensive assembly time and specialized personnel, while cartridge seals are costly due to the need for specific components and spacer elements that wear out, making reassembly challenging.

Innovation Solution

A mechanical seal design featuring a supporting body with a through cavity housing pre-assembled sealing rings and elastic means, including a stop ring that lifts during shaft insertion, eliminating the need for a tubular body and spacer elements, allowing for the use of standard components and simplified assembly and reassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional mechanical seal is used, then the sealing function is provided, but the assembly time is considerable and specialized personnel are required

Engineering Contradiction:
Improvesealing functionVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The mechanical seal is divided into a stationary part (supporting body with fixed sealing ring) and a rotating part (rotary ring with elastic means), allowing independent assembly and positioning. The stationary sealing ring is fixed to the supporting body while the rotary sealing ring is mounted on the shaft, enabling streamlined assembly procedures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The elastic means (spring) are pre-loaded during manufacturing to exert a predetermined thrusting action on the sealing rings. This preliminary action ensures correct pre-loading is achieved without requiring specialized personnel during assembly, as the thrusting force is already configured in the rotary ring assembly.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If a cartridge seal is used, then assembly is simplified to a single operation, but the cost increases due to specific components and spacer elements

Engineering Contradiction:
Improveassembly simplicityVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The mechanical seal design uses standard, universally available components rather than specialized cartridge seal parts. The supporting body, sealing rings, and elastic means are conventional elements that can be sourced from standard inventory, eliminating the need for expensive proprietary components and reducing manufacturing costs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The design extracts and eliminates the spacer element that is characteristic of cartridge seals. By using a stop ring positioned against a supporting surface to maintain spacing, the patent removes the need for separate spacer components, thereby reducing part count and manufacturing cost while maintaining assembly simplicity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If spacer elements are used in cartridge seals, then the seal functions correctly, but they wear out and complicate reassembly

Engineering Contradiction:
Improveseal functionVSAvoidreassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The stop ring is designed as a durable, non-wearing component that replaces the consumable spacer element. While the spacer in cartridge seals wears out and must be replaced, the stop ring positioned against the supporting surface maintains its function throughout the seal's service life, facilitating easier repair and reassembly.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

Instead of using a spacer element that maintains distance between components (as in cartridge seals), the invention uses a stop ring that limits the position of the rotary ring assembly by bearing against the supporting surface. This inverted approach eliminates the wearing spacer while achieving the same spacing function through a non-consumable component.

Inventive Principle:
Principle #13The other way round (Inversion)

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

This design reduces installation and reinstallation complexity, lowers costs by using standard components, and eliminates the need for spacer elements, enabling easier and more cost-effective assembly and reuse of the mechanical seal.

Implementation Method 1

Elastic means are provided, which thrust the two rings against each other with a pre-defined pressure

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

said spacer element is configured so that it wears out during the operation of the seal, in such a way as to physically separate the tubular body from the supporting body and eliminate any friction between the two components

Methodology Applied
Scientific EffectWear: Wear

Data Source

PatentEP2674646B1Mechanical seal and sealing system comprising said mechanical seal
Publication Date: 2015.07.29 CALPEDA
  • EP2674646B1 patent drawingFigure 1
  • EP2674646B1 patent drawingFigure 2
  • EP2674646B1 patent drawingFigure 3~4

AI summary

The invention is a mechanical seal (1; 1'; 1") for a fluid, comprising a supporting body (2) that delimits a through cavity (3) extending between two opposing openings (4, 5) that delimit the through cavity (3) according to a longitudinal direction (X), in which the following components are arranged: a first sealing ring (6) associated with a first opening (4); a second sealing ring (7) facing the first sealing ring (6) and revolvingly associated with the supporting body (2); elastic means (10) compressed between the supporting body (2) and a sealing ring (6, 7) so as to thrust the sealing rings (6, 7) against each other. The seal comprises a stop ring (11; 11') interposed between the second sealing ring (7) and a supporting surface (12) that delimits the perimeter of the second opening (5), the stop ring (11, 11') being configured in such a way that it can be thrust by the elastic means (10) in a stop position against the supporting surface (12). The stop ring (11; 11') is furthermore configured so that, in the stop position, it has a portion (11 a) facing the inside of the second opening (5).