Electromagnetic Cartridge Seal Load Control for Dry Pump Modes

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Solution Overview

Problem

Legacy mechanical seals, relying on springs or permanent magnets, fail to adapt to varying operational modes of pumps, leading to premature wear and increased maintenance due to lack of lubrication during dry modes, and require frequent replacements.

Innovation Solution

An electromagnetic cartridge seal system using an electromagnet as a force-applying mechanism, coupled to a carbon seal and elastomeric secondary seals, dynamically adjusts its load based on operational signals from inlet shut-off valves to maintain a tight seal in both wet and dry modes, reducing wear and maintenance needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring or permanent magnet is used to apply force on the seal, then the seal maintains contact between sealing faces, but the seal cannot adapt to varying operational modes leading to premature wear

Engineering Contradiction:
Improveseal reliabilityVSAvoidadaptability to operational modes
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs an electromagnet instead of a static spring or permanent magnet to apply force on the seal. The electromagnet can dynamically adjust its magnetic field strength in response to operational mode changes (wet vs. dry mode), allowing the seal to adapt its loading conditions and prevent premature wear during dry operation while maintaining effective sealing during wet operation.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the seal operates in dry mode without lubrication, then the pump can run without fluid, but the seal experiences increased wear and requires frequent replacement

Engineering Contradiction:
Improvepump operational flexibilityVSAvoidseal service life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The electromagnet dynamically reduces or eliminates force application to the seal during dry mode operation, preventing excessive wear that would occur with constant spring or magnet pressure. This extends seal life while allowing the pump to operate flexibly in both wet and dry conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the seal by adjusting the electromagnet's field strength based on lubrication availability. During dry mode, the parameter (magnetic force) is reduced to minimize wear, while during wet mode, full sealing force is restored, optimizing both productivity and durability.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a static mechanical seal configuration is used, then the structure is simple, but the seal cannot respond to changing operational conditions

Engineering Contradiction:
Improveseal structure complexityVSAvoidresponse to operational conditions
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the purely mechanical spring-based force application system with an electromagnet-driven system. This substitution introduces electrical control capability, allowing the seal to respond dynamically to operational conditions through electromagnetic field adjustment while maintaining relatively simple mechanical structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 electromagnetic cartridge seal extends the life of seals, reduces maintenance, and provides uniform load distribution, ensuring reliable operation and reduced costs by leveraging existing system components and signals for mode control.

Implementation Method 1

Other types of legacy seals use permanent magnets within the mechanical seal to maintain the contact of the sealing faces during operation

Methodology Applied
Scientific EffectElectromagnet: Electromagnet

Implementation Method 2

controlling a magnitude of the magnetic force with the signal

Methodology Applied
Scientific EffectElectromagnetic force control: Electromagnet

Data Source

PatentEP3457008B1Electromagnetic cartridge seal
Publication Date: 2023.03.22 HAMILTON SUNDSTRAND CORP
  • EP3457008B1 patent drawingFigure 1
  • EP3457008B1 patent drawingFigure 2
  • EP3457008B1 patent drawingFigure 3

AI summary

Embodiments include an apparatus and techniques for operating an electromagnetic cartridge seal. Embodiments include operating a cartridge seal in one of a plurality of modes, and receiving (304) a signal at a force applying mechanism of the cartridge seal, the force applying mechanism being coupled to a primary sealing component of the cartridge seal. Embodiments also include controlling (306) the force applying mechanism based at least in part on the received signal.