Interstage capacity control valve with separate drive and stabilization linkages

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Solution Overview

Problem

Multi-stage compressors experience instability and reduced efficiency due to low-momentum zones and adverse pressure gradients caused by return vanes at partial load conditions, leading to narrower operating ranges.

Innovation Solution

The interstage capacity control valve uses separate and discrete attachments for linkages connected to the drive and throttle rings, reducing stress on projections and simplifying assembly, thereby lowering parts costs and increasing durability while smoothing operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If common projections are used for attaching both drive linkages and stabilization linkages to the throttle ring, then the device complexity is reduced, but the stress on the projections increases and durability decreases

Engineering Contradiction:
Improvestructure complexityVSAvoiddurability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The attachment projections are segmented into two distinct sets: drive linkage attachment projections and stabilization linkage attachment projections. This segmentation separates the functional loads, preventing stress concentration on single projections and improving durability without significantly increasing overall structural complexity.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If common projections are used for both linkages, then assembly is simplified, but the torque required to operate the valve increases

Engineering Contradiction:
Improveassembly simplicityVSAvoidtorque requirement
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

By segmenting the attachment projections into separate drive and stabilization sets, the torque loads are distributed across different projection groups. This reduces the cumulative torque requirement on any single projection set, making operation smoother while maintaining assembly simplicity.

Inventive Principle:
Principle #1Segmentation

3Reliability

If separate attachments are used for drive and stabilization linkages, then stress on projections is reduced and durability increases, but device complexity increases

Engineering Contradiction:
ImprovedurabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The throttle ring exhibits local quality differentiation with distinct attachment projection zones optimized for specific functions. Drive linkage projections are positioned and dimensioned for drive function, while stabilization projections are positioned and dimensioned for stabilization function, reducing stress concentrations locally without requiring complete redesign of the entire structure.

Inventive Principle:
Principle #3Local quality

4Ease of operation

If separate attachments are used for drive and stabilization linkages, then operation smoothness improves, but parts cost increases

Engineering Contradiction:
Improveoperation smoothnessVSAvoidparts cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The separate attachment projections are implemented as localized features on the throttle ring rather than completely separate components. This approach improves operation smoothness by distributing loads more evenly while minimizing the increase in parts cost, as the projections are integrated into the existing throttle ring structure.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4717925A1Interstage capacity control valve with separate drive and stabilization linkages
Publication Date: 2026.04.01 TRANE INTERNATIONAL INC
  • EP4717925A1 patent drawingFigure 1
  • EP4717925A1 patent drawingFigure 2A
  • EP4717925A1 patent drawingFigure 2B

AI summary

Stabilization and drive linkages of a compressor capacity control valve are separated, for example physically and/or entirely, such that the respective linkages use separate and discrete attachment projections provided on the drive and throttle rings of the capacity control valve. The use of discrete attachment projections places lower stress on each attachment projection compared to linkages including paired stabilization and drive linkages sharing some attachment projections. The stabilization linkages can connect to an interstage casing. The linkage assemblies allow the throttle ring to be driven in an axial direction so as to open or close the compressor capacity control valve.