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 employs separate and discrete attachments for linkages connected to the drive and throttle rings, reducing stress on projections and simplifying assembly, while lowering parts costs and increasing durability by minimizing linkage tension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

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

Engineering Contradiction:

Improveattachment structure complexityVSAvoidprojection durability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The attachment structure is segmented into separate drive linkage attachment projections and separate stabilization linkage attachment projections on the throttle ring. This segmentation distributes the stress from different linkages to different projections, preventing overload on any single projection while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If common projections are used for both linkages, then parts costs are reduced, but the stress concentration on projections increases

Engineering Contradiction:

Improveparts costVSAvoidprojection stress

Core Design Contradiction:

Ease of manufactureVSStress or pressure

Solution Approach 1:

The throttle ring is designed with multiple separate attachment projections distributed around its circumference. Each projection handles the stress from a specific linkage independently, preventing stress concentration that would occur if multiple linkages shared common attachment points.

Inventive Principle:

Principle #1Segmentation

3Force

If the torque on the drive ring is high, then the drive linkages can effectively control the throttle ring, but the operation of the capacity control valve becomes less smooth

Engineering Contradiction:

Improvedrive linkage forceVSAvoidvalve operation smoothness

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The drive linkages are configured to apply force dynamically to the drive ring, allowing the system to operate smoothly across different positions. The linkage geometry and attachment points are designed to optimize the mechanical advantage and force distribution during operation, reducing the peak torque required while maintaining effective control.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12504025B1Interstage capacity control valve with separate drive and stabilization linkages

Publication Date: 2025.12.23 TRANE INTERNATIONAL INC

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.