Hirth Coupling Seal Assembly for Compressor Rotor Fluid Ingress

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Solution Overview

Problem

Turbomachinery components, particularly Hirth couplings in centrifugal compressors, face durability issues due to exposure to contaminants and high centrifugal forces, leading to corrosion and potential structural damage.

Innovation Solution

A seal assembly is disposed within a circumferentially extending groove in the toothed meshing interface of the Hirth coupling, securely held in place and positioned radially closer to the outer diameter, inhibiting process fluid passage and reducing exposure to centrifugal forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If Hirth coupling is exposed to process fluid, then the coupling can be positioned in the fluid flow path for structural support, but the coupling becomes susceptible to corrosion and contamination from the process fluid

Engineering Contradiction:

Improvestructural support capabilityVSAvoidcorrosion and contamination exposure

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

A seal assembly is introduced as an intermediary component between the Hirth coupling and the process fluid. The seal assembly includes a seal ring positioned in a groove of the Hirth coupling that extends radially outwardly, creating a barrier that prevents direct contact between the process fluid and the Hirth coupling teeth, thereby protecting against corrosion and contamination while maintaining structural support functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If seal assembly is added to protect Hirth coupling, then corrosion resistance improves, but device complexity increases

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The seal assembly is localized to only the specific area where protection is needed - the toothed meshing interface of the Hirth coupling. The seal ring is positioned in a groove that confines the sealing function to the critical interface zone, providing corrosion protection exactly where the process fluid would cause damage without adding complexity to the entire rotor structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The seal ring is nested within a groove of the Hirth coupling, with the groove extending radially outwardly from the toothed meshing interface. This nesting approach allows the seal assembly to be integrated into the existing Hirth coupling structure rather than adding external components, minimizing overall device complexity while maintaining protective functionality

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentEP4185776B1Compressor rotor having seal assembly within hirth coupling

Publication Date: 2025.10.01 SIEMENS ENERGY GLOBAL GMBH & CO KG

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AI summary

A compressor rotor for turbomachinery, such as a centrifugal compressor, is provided. Disclosed embodiments benefit from a seal assembly including one or more seal members positioned within a Hirth coupling to inhibit passage of process fluid being processed by the compressor. A circumferentially extending groove is arranged in a toothed meshing interface of the Hirth coupling to receive and securely hold the one or more seal members within the Hirth coupling. The groove may be configured with features, such as may define a dovetail groove, to facilitate assembly of certain seal members into the groove. Disclosed embodiments can make use of any of various sealing modalities for the seal member within the Hirth coupling based on the needs of a given application.